CN110072314B

CN110072314B - LED lighting device

Info

Publication number: CN110072314B
Application number: CN201910044236.8A
Authority: CN
Inventors: 郑暎都; 陈成昊; 韩相昱; 郑蕙万
Original assignee: Seoul Semiconductor Co Ltd
Current assignee: Seoul Semiconductor Co Ltd
Priority date: 2014-12-12
Filing date: 2015-12-14
Publication date: 2021-06-22
Anticipated expiration: 2035-12-14
Also published as: CN105704854A; CN110072314A; CN109951920B; CN109951920A; CN205336575U; WO2016093534A1; CN105704854B

Abstract

The invention discloses an LED lighting device. The LED lighting device includes: a rectifying unit configured to rectify an alternating-current voltage and output the rectified voltage as a first drive voltage; a loopback compensation section for charging the second drive voltage using the rectified voltage; an LED light emitting part including a first LED group and a second LED group, at least one of the LED groups emitting light when receiving a first driving voltage in a non-compensation section in which the LED light emitting part is driven by a rectified voltage and emitting light when receiving a second driving voltage in a compensation section in which the LED light emitting part is driven by a second driving voltage looped back to the compensation section; and an LED driving controller including a first constant current switch and a second constant current switch, and controlling driving of the first LED group and the second LED group based on a level of the rectified voltage, output light of the LED light emitting section being substantially constant between a non-compensation section and a compensation section.

Description

LED lighting device

The present application is a divisional application of an invention patent application having an application date of 2015, 12/14/h, an application number of 201510973236.8, and an invention name of "LED driving circuit with improved flicker performance and LED lighting device including the same".

Technical Field

The present invention relates to an LED driving circuit with improved flicker performance and an LED lighting device including the same. More particularly, the present invention relates to an LED driving circuit and an LED lighting device including the same, which can reduce flicker performance of light output deviation of the LED lighting device occurring in an operating section by eliminating an LED turn-off section in an LED lighting device in an alternating sequential driving manner.

Background

A general LED driving method is a dc driving method. When the DC driving method is used, an AC-DC converter such as an SMPS is required, and such a power converter has the following problems: the manufacturing unit price of the lighting fixture is improved; making miniaturization of the lighting fixture difficult; reducing the energy efficiency of the lighting fixture; the shorter lifetime results in a shortened lifetime of the lighting fixture.

To solve the above-mentioned problems of the dc driving method, an ac driving method of the LED has been proposed. However, when the circuit based on the above-described technique is used, there is a problem that not only is the power factor lowered due to the inconsistency between the input voltage and the current output from the LED, but also a flicker phenomenon occurs in which the user can perceive the flicker of the illumination.

Fig. 1 is a conceptual diagram for explaining Flicker (Flicker) performance. Recently, Energy Star (Energy Star) SPEC has given the following definitions and specifications for scintillation as a standard for scintillation performance.

(1) Definition of flicker

The flicker is a phenomenon in which the illumination brightness is changed for a predetermined time, and in a serious case, the user may perceive the shaking or flickering of the light. This flicker is mostly a phenomenon caused by the difference between the maximum light output and the minimum light output within a predetermined time.

(2) Class of indicators representing flicker performance

a) Flicker Index (Flicker Index): as shown in fig. 1, the flicker index is a value obtained by dividing an Area (Area1) equal to or greater than the average light output by the entire light output Area (Area1+ Area2) on the light output waveform diagram of the first cycle. Therefore, the flicker index is a value that indicates data-wise how much light is above the average light output occurring in one cycle, and the lower the flicker index is, the better the flicker level is.

Percent Flicker (Percent Flicker) or Modulation Depth (Modulation Depth): the flicker percentage refers to an index for digitizing the minimum light amount and the maximum light amount in a predetermined time. Such a flicker percentage can be calculated by 100 × (maximum light amount-minimum light amount)/(maximum light amount + minimum light amount).

(3) Flicker index specification for energy stars

Light output waveform (Light output waveform) of 120Hz or more

Flicker index ≦ frequency × 0.001 (except at Max. Dimmer, above 800 Hz) (thus, flicker index at 120Hz ≦ 0.12)

(4) Results of the study conducted on the percent scintillation

According to the paper on which the study of the percentage of flicker was carried out,

the interval in which the flicker percentage is less than 0.033 x 2 x the frequency or less is defined as an interval having no influence,

the interval in which the flicker percentage is less than 0.033 × 2 × frequency or less is defined as a low risk interval.

As mentioned above, the flicker level is increasingly being regarded as an important criterion for the performance of LED lighting devices.

In addition, fig. 2 is a schematic structural block diagram of a four-step sequentially driven LED lighting device according to the related art, and fig. 3 is a waveform diagram illustrating a relationship between a driving voltage and an LED driving current of the four-step sequentially driven LED lighting device according to the related art as shown in fig. 2. The following will discuss problems of the LED lighting device according to the related art with reference to fig. 2 and 3.

First, as shown in fig. 2, the LED lighting device 100 according to the related art may include: an LED rectifying unit 10, an LED light emitting unit 20, and an LED drive control unit 30.

Rectifying part 10 of LED lighting device 100 according to the related art is coupled to an external power supplyReceived alternating voltage V_ACRectifies the voltage to generate a rectified voltage Vrec, and outputs the generated rectified voltage Vrec to the LED light emitting unit 20 and the LED drive control unit 30. As such a rectifying unit 10, one of various known rectifying circuits such as a full-wave rectifying circuit and a half-wave rectifying circuit may be used, and fig. 2 illustrates a bridge full-wave rectifying circuit including four diodes D1, D2, D3, and D4. Further, the LED light emitting unit 20 according to the related art is configured by four LED groups of the first to 4 th LED groups 21 to 24, and is configured to be capable of being sequentially turned on and sequentially turned off according to the control of the LED driving control unit 30. In addition, the LED drive control section 30 according to the related art performs a control function capable of sequentially turning on and sequentially turning off the first to fourth LED groups 21 to 24 according to the voltage level of the rectified voltage Vrec.

In particular, the LED driving control section 30 according to the related art constitutes a form that can perform a constant current control function in sequential driving intervals by increasing or decreasing the LED driving current according to the voltage level of the input voltage (i.e., the rectified voltage Vrec), and has an object to: for improving Power Factor (PF) and Total Harmonic Distortion (THD) by making LED driving current show a step wave form similar to a sine wave, thereby improving power quality of the LED lighting device.

Hereinafter, the operation of the LED lighting device 100 according to the above-described conventional art will be discussed in more detail with reference to fig. 3. As shown in fig. 3, the LED driving control part 30 according to the related art may include a first constant current switch SW1, a second constant current switch SW2, a third constant current switch SW3, and a fourth constant current switch SW4 in order to control sequential driving of the LED groups. Specifically, the LED drive control section 30 according to the related art realizes by constant current control: in a section (first step operation section) where the rectified voltage Vrec is equal to or higher than the first forward voltage level Vf1 and lower than the second forward voltage level Vf2, only the first LED group 21 is turned on, and the LED driving current I is set to be equal to or higher than the second forward voltage level Vf2_LEDBecomes the first LED drive current. Similarly, the LED drive control section 30 according to the related art realizes by control: when the rectified voltage Vrec is higher than the second forward voltage level Vf2In the interval less than the third forward voltage level Vf3, the first constant current switch SW1 is turned off and the second constant current switch SW2 is turned on, so that only the first LED group 21 and the second LED group 22 are turned on and the LED driving current I is driven_LEDTo a second LED drive current I_LED2. In addition, the LED drive control section 30 according to the related art realizes by constant current control: in a section (third step operation section) where the rectified voltage Vrec is equal to or higher than the third forward voltage level Vf3 and smaller than the fourth forward voltage level Vf4, the second rectifying switch SW2 is opened and the third rectifying switch SW3 is closed, so that the first to third LED groups 21 to 23 are lit, and the LED driving current I is caused to flow_LEDInto a third LED drive current I_LED3. Finally, the LED drive control section 30 according to the related art realizes by constant current control: in a section (fourth step operation section) in which the rectified voltage Vrec is equal to or higher than the fourth forward voltage level Vf4, the third constant current switch SW3 is opened, and the fourth constant current switch SW4 is closed, so that all of the first to fourth LED groups 21 to 24 are turned on, and the LED driving current I is set to be equal to or higher than the fourth forward voltage level Vf4_LEDTo a fourth LED drive current I_LED4. As shown in fig. 3, the LED driving current in the second step operation section (i.e., the second LED driving current I) is controlled to be the same_LED2) Is larger than the LED drive current in the first step operation interval (i.e. the first LED drive current I)_LED1) Also, the LED driving current in the third step operation section (i.e., the third LED driving current I) is controlled to be the third LED driving current I_LED3) Is greater than the LED drive current in the second-step operating region (i.e., the second LED drive current I)_LED2) And the fourth LED is driven by the current I through control_LED4And max. Accordingly, the entire light output of the LED illumination device 100 according to the related art may have a step wave shape as shown in fig. 3. Accordingly, in the case of using the LED lighting device 100 according to the related art as described above, since the total number of LEDs emitting light and the driving current are different from each other according to the operation sections, the light outputs are different from each other for each operation section, and thus there is a problem in that the user may feel inconvenience due to the difference in the light outputs for each operation section and the flickering performance as described above is deteriorated. Namely, with respect to the conventional techniques as described aboveIn the case of the sequential driving LED lighting device, the flicker percentage is 100%, so that it is required to be improved.

In addition, the LED lighting device 100 according to the related art as described above is configured as follows: the sequential driving is controlled based on a voltage level of a rectified voltage Vrec which is a driving voltage supplied to the LED light emitting section 20. However, the voltage detection method described above has a problem that it cannot accurately reflect the current/voltage characteristics according to the temperature. That is, although the forward voltages of the LED groups are different from each other according to the "operating temperature of the LEDs", the voltage detection method cannot accurately reflect the I/V characteristics according to the temperature of the LEDs, and therefore, a phenomenon occurs in which the LED driving current (LED light output) is instantaneously reduced or overlapped (overlapshot) at a time point when the operating interval is changed (for example, a time point when the operating interval is changed from the first-step operating interval to the second-step operating interval), and there is a problem in that the light output of the LED lighting device is unstable.

Disclosure of Invention

The present invention aims to solve the problems of the prior art as described above.

The present invention provides an LED driving circuit with improved flicker performance and an LED lighting device including the same, wherein the LED lighting device in an alternating sequential driving mode reduces light output deviation by eliminating non-light emitting intervals, thereby providing light with natural feeling to a user.

Another object of the present invention is to provide an LED driving circuit with improved flicker performance and an LED lighting device including the same, which controls the magnitude of an LED driving current supplied to LEDs based on the number of LEDs lit per operation interval in an alternating sequential driving manner, thereby reducing light output deviation of the LED lighting device occurring between operation intervals.

Another object of the present invention is to provide an LED driving circuit with improved flicker performance, which controls sequential driving between LED groups based on an LED driving current detection method, thereby providing a constant light output, and an LED lighting device including the same.

Another object of the present invention is to provide an LED driving circuit with improved flicker performance and an LED lighting device including the same, in which the LED lighting device in an alternate sequential driving method improves circuit efficiency by using a loopback compensation part that can discharge through a dual discharge path, and can increase the amount of light.

The features of the present invention for achieving the above-described object of the present invention and achieving the following specific effects of the present invention are configured as follows.

According to one aspect of the present invention, there is disclosed an LED illumination device comprising: a rectifying unit that full-wave rectifies an alternating-current voltage applied by being connected to an alternating-current power supply and supplies the full-wave rectified voltage to an LED light-emitting unit as a first drive voltage; an LED light emitting unit including first to nth LED groups, wherein n is a positive integer of 2 or more, and configured to receive the rectified voltage from the rectifying unit as the first driving voltage in a non-compensation interval and to emit light, and to receive a second driving voltage from a loopback compensating unit in a compensation interval; a loop-back (loop-back) compensation part having one end connected to a negative end of one of the first to n-1 th LED groups through a charging path, the one end additionally connected to a positive end of the one of the first to n-1 th LED groups through a discharging path, and the other end connected to an LED driving control part, and charging energy using the rectified voltage in a charging interval and supplying the second driving voltage to the LED light emitting part in the compensation interval; an LED drive control part for detecting LED drive currents flowing through constant current switches respectively connected to the first to nth LED groups and controlling sequential driving of the first to nth LED groups according to the detected LED drive currents.

Preferably, the loop-back compensation part may be connected to a positive terminal of the first LED group to provide a second driving voltage to the first LED group in the compensation interval.

Preferably, the LED driving control part may set an LED driving current value for each operation section based on a total number of LEDs emitting light for each operation section, and perform constant current control on the LED driving currents in the relevant operation section according to the set LED driving current value for each operation section, and the first to nth LED driving currents are set to be sequentially reduced, wherein the LED driving currents for each operation section are the first to nth LED driving currents.

Preferably, the LED driving control part may set the LED driving current value for each operation section to be inversely proportional to the total number of LEDs emitting light for each operation section, and perform constant current control on the LED driving currents in the relevant operation section according to the set LED driving current value for each operation section, where the LED driving currents for each operation section are the first to nth LED driving currents.

Preferably, the LED light emitting unit may include a first LED group and a second LED group, and a difference between a light output of the first LED group during a first operation interval and a light output of the first LED group and the second LED group during a second operation interval may be equal to or less than a predetermined light output deviation.

Preferably, the LED light emitting unit may include a first LED group and a second LED group, and the second driving voltage may be equal to or higher than a forward voltage level of the first LED group.

Preferably, the LED light emitting unit may include a first LED group and a second LED group, and the peak value of the rectified voltage may be 2 times or more a forward voltage level of the first LED group.

Preferably, the LED driving control part may further include: the first to nth LED driving current setting portions are capable of setting corresponding LED driving current values among the first to nth LED driving current values, respectively.

Preferably, the first to nth LED driving current setting portions may be respectively configured by variable resistors.

Preferably, the LED driving control part may include: and the first constant current switch to the nth constant current switch are respectively connected to the respective negative ends of the first LED group to the nth LED group, are connected or separated from the first current path to the nth current path according to the operation intervals, and are used for carrying out constant current control on the LED driving current in each operation interval.

Preferably, the LED driving control part may further include: and the (n + 1) th constant current switch is positioned between the loopback compensation part and the LED drive control part, is connected with or separated from an (n + 1) th current path between the loopback compensation part and the LED drive control part, and performs constant current control on the (n + 1) th LED drive current in the charging interval.

Preferably, the LED driving control part may detect a charging current flowing through the (n + 1) th constant current switch connected to the loop back compensation part to determine whether a charging section enters and leaves, and open the nth constant current switch at a time point of entering the charging section and close the nth constant current switch at a time point of leaving the charging section.

Preferably, the LED driving control unit may close the (n + 1) th constant current switch connected to the loop back compensation unit at a time point when the (n-1) th operation section enters the (n) th operation section in accordance with a rise in the rectified voltage, detect a charging current flowing therethrough, turn off the (n) th LED group and enter the charging section by turning off the (n) th constant current switch when the detected charging current rises to a predetermined value or more, and turn on the (n) th constant current switch to turn on the (n) th LED group again and enter the (n) th operation section when the detected charging current falls to a predetermined value or less after entering the charging section.

Preferably, the n +1 th LED driving current value may be set to be the same as the n-1 th driving current value.

Preferably, the LED light emitting part may include a first LED group and a second LED group, and a forward voltage level of the first LED group may be greater than a forward voltage level of the second LED group.

Preferably, the LED lighting device may further include: and an n +2 th switch located between the n-1 th LED group and a node between the n-th LED group and the loopback compensation part, and turned on or off according to control of the LED driving control part, wherein the LED driving control part turns on the n +2 th switch at a time point when an n-th operation interval enters, and turns off the n +2 th switch at a time point when the n-th operation interval enters.

Preferably, the LED lighting device may further include: and a second compensation unit connected in parallel to the nth LED group, and configured to be charged during an nth operation interval and supply a driving voltage to the nth LED group during a non-emission interval in which the nth LED group does not emit light.

Preferably, the loopback compensation part may be connected in parallel to the nth LED group, and the other end of the loopback compensation part and the negative electrode end of the nth LED group are connected to the driving control part through the nth constant current switch in common.

Preferably, the LED light emitting part may include a first LED group and a second LED group, and a forward voltage level of the first LED group may be less than or equal to a forward voltage level of the second LED group.

Preferably, the LED light emitting part may include a first LED group, a second LED group, and a third LED group, the loopback compensation part may be connected in parallel to the second LED group and the third LED group, and one end of the loopback compensation part is connected to a positive terminal of the first LED group, so as to perform charging during a second operation interval and a third operation interval, and provide the second driving voltage to the first LED group during the compensation interval.

Preferably, the LED light emitting part may include a dummy load (dummy load) instead of the third LED group.

Preferably, the LED lighting device may further include: and a second compensation unit connected in parallel to the nth LED group, and configured to be charged during the nth operation interval and supply a driving voltage to the nth LED group during a non-emission interval in which the nth LED group does not emit light.

Preferably, the LED lighting device may further include: and a second compensation unit which is connected in series to the nth LED group, charges the n-th LED group in a section in which a voltage level of the rectified voltage is equal to or higher than an nth forward voltage level, and supplies a driving voltage to the nth LED group through a discharge path connected in parallel to the nth LED group during a non-emission section in which the nth LED group does not emit light.

Preferably, the LED light emitting part may include a first LED group, a second LED group, and a third LED group, a node between the second LED group and the third LED group is connected to a negative terminal of the rectifying part, the loopback compensating part is connected in parallel with the second LED group and the third LED group, one terminal of the loopback compensating part is connected to the negative terminal of the first LED group and is charged during a second operation interval and a third operation interval, and the second driving voltage is supplied to the first LED group and the third LED group during the discharge interval.

According to another aspect of the present invention, there is disclosed an LED driving circuit for controlling driving of an LED light emitting section including first to nth LED groups and receiving a full-wave rectified voltage as a first driving voltage from a rectifying section, n being a positive integer of 2 or more, wherein the LED driving circuit includes: a loop compensation part, one end of which is connected to the negative terminal of any one of the first to n-1 th LED groups through a charging path, the other end of which is connected to the positive terminal of any one of the first to n-1 th LED groups through a discharging path, and the other end of which is connected to the LED driving control part, and which charges energy by using the rectified voltage in a charging interval and provides a second driving voltage to the LED light emitting part in a compensation interval; and an LED drive control unit which detects LED drive currents flowing through the constant current switches connected to the first to nth LED groups, respectively, and controls sequential driving of the first to nth LED groups according to the detected LED drive currents.

Preferably, the loop-back compensation part may be connected to a positive terminal of the first LED group so as to provide a second driving voltage to the first LED group in the compensation interval.

Preferably, the LED light emitting unit may include a first LED group and a second LED group, and the peak value of the rectified voltage may be 2 times or more the forward voltage level of the first LED group.

Preferably, the LED driving circuit may further include: and an n +2 th switch located between the n-1 th LED group and a node between the n-th LED group and the loopback compensation part, and turned on or off according to control of the LED driving control part, wherein the LED driving control part turns on the n +2 th switch at a time point when an n-th operation interval enters, and turns off the n +2 th switch at a time point when the n-th operation interval enters.

Preferably, the LED driving circuit may further include: and a second compensation unit connected in parallel to the nth LED group, and configured to be charged during an nth operation interval and supply a driving voltage to the nth LED group during a non-emission interval in which the nth LED group does not emit light.

Preferably, the LED light emitting part may include a dummy load instead of the third LED group.

Preferably, the LED driving circuit may further include: and a second compensation unit connected in parallel to the nth LED group, and configured to be charged during the nth operation interval and supply a driving voltage to the nth LED group during a non-emission interval in which the nth LED group does not emit light.

Preferably, the LED driving circuit may further include: and a second compensation unit which is connected in series to the nth LED group, charges the n-th LED group in a section in which a voltage level of the rectified voltage is equal to or higher than an nth forward voltage level, and supplies a driving voltage to the nth LED group through a discharge path connected in parallel to the nth LED group during a non-emission section in which the nth LED group does not emit light.

According to still another aspect of the present invention, there is disclosed an LED illumination device, comprising: a rectifying unit that full-wave rectifies an alternating-current voltage applied by being connected to an alternating-current power supply and supplies the full-wave rectified voltage to an LED light-emitting unit as a first drive voltage; an LED light emitting unit configured to include a first LED group and a second LED group, and to emit light by receiving the rectified voltage from the rectifying unit as the first drive voltage in a non-compensation interval and to emit light by receiving a second drive voltage from a loopback compensating unit in a compensation interval; a loop compensation unit between a node between the first LED group and the second LED group and the LED driving control unit, for charging energy by using the rectified voltage in a charging interval, and for providing the second driving voltage to the first LED group and the second LED group in the compensation interval, wherein the charging interval is a first operating interval; and an LED driving control part detecting LED driving currents flowing through constant current switches respectively connected to the first LED group and the second LED group, and controlling deformation of the first LED group and the second LED group to be sequentially driven according to the detected LED driving currents, wherein the LED driving control part detects a charging current flowing through the constant current switch connected to the loopback compensation part, thereby determining whether a charging interval enters and departs, and opens the constant current switch connected to the second LED group at a time point of entering the charging interval, and closes the constant current switch connected to the second LED group at a time point of departing from the charging interval.

According to still another aspect of the present invention, there is disclosed an LED driving circuit for controlling driving of an LED light emitting section including a first LED and a second LED group and receiving a full-wave rectified voltage as a first driving voltage from a rectifying section, wherein the LED driving circuit includes: a loop compensation unit between a node between the first LED group and the second LED group and the LED driving control unit, for charging energy by using the rectified voltage in a charging interval, and for providing a second driving voltage to the first LED group and the second LED group in a compensation interval, wherein the charging interval is a first operating interval; and an LED driving control part detecting LED driving currents flowing through constant current switches respectively connected to the first LED group and the second LED group, and controlling deformation of the first LED group and the second LED group to be sequentially driven according to the detected LED driving currents, wherein the LED driving control part detects a charging current flowing through the constant current switch connected to the loopback compensation part, thereby determining whether a charging interval enters and departs, and opens the constant current switch connected to the second LED group at a time point of entering the charging interval, and closes the constant current switch connected to the second LED group at a time point of departing from the charging interval.

According to still another aspect of the present invention, there is disclosed an LED illumination device, including: a rectifying unit that full-wave rectifies an alternating-current voltage applied by being connected to an alternating-current power supply and supplies the full-wave rectified voltage to an LED light-emitting unit as a first drive voltage; an LED light emitting unit including first to nth LED groups, the LED light emitting unit receiving the rectified voltage from the rectifying unit as the first driving voltage in a non-compensation interval and emitting light, and receiving a second driving voltage from a loopback compensating unit in a compensation interval and emitting light, wherein n is a positive integer of 2 or more; a loop-back compensation unit between a node between the m-th LED group and the m + 1-th LED group and the LED driving control unit, for charging energy by using the rectified voltage in a charging interval, and supplying the second driving voltage to the second group of LED groups during a first compensation interval of the compensation interval, and supplying the second driving voltage to the second group of LED groups and the first group of LED groups during a second compensation interval of the compensation interval, respectively, wherein m is a positive integer smaller than n, the second group of LED groups are the m + 1-th LED groups, and the first group of LED groups are the first to the m-th LED groups; and an LED drive control unit that controls driving of the first to nth LED groups in accordance with a voltage level of the rectified voltage.

Preferably, the loopback compensation part may be connected to the positive terminal of the (m + 1) th LED group through a first discharge path and connected to the positive terminal of the first LED group through a second discharge path.

Preferably, the first group of LED groups is drivable by the first driving voltage during the first compensation interval.

Preferably, the LED groups of the first group and the LED groups of the second group may be driven independently of each other during the first compensation interval and the second compensation interval.

Preferably, the forward voltage level of the LED group of the first group may be less than or equal to the forward voltage level of the LED group of the second group.

Preferably, the LED driving control part may further include: and first to nth LED drive current setting sections for setting corresponding LED drive current values among the first to nth LED drive current values, respectively.

According to still another aspect of the present invention, there is disclosed an LED driving circuit for controlling driving of an LED light emitting section including first to nth LED groups and receiving a full-wave rectified voltage as a first driving voltage from a rectifying section, n being a positive integer of 2 or more, the LED driving circuit including: a loop-back compensation unit located between a node between the mth LED group and the m +1 th LED group and the LED driving control unit, for charging energy by using the rectified voltage in a charging interval, providing a second driving voltage to the second group of LED groups during a first compensation interval of the compensation interval, and providing the second driving voltage to the second group of LED groups and the first group of LED groups during a second compensation interval of the compensation interval, respectively, wherein m is an integer less than n, the second group of LED groups are the m +1 th LED group to the nth LED group, and the first group of LED groups are the first LED group to the mth LED group; and an LED drive control unit that controls driving of the first to nth LED groups in accordance with a voltage level of the rectified voltage.

According to a preferred embodiment of the present invention, the non-light-emitting section is eliminated by using a loop-back (loop-back) compensation section, thereby providing an effect of reducing light output deviation and providing a user with light rich in natural feeling.

Further, according to the present invention, the LED lighting device of the alternating sequential driving method according to the present invention can provide the following effects: the magnitude of the LED driving current supplied to the LEDs is controlled based on the number of LEDs lit per operation interval, thereby reducing light output deviation of the LED lighting device occurring in the operation interval.

In addition, according to the present invention, the following effects can be brought about: the sequential driving between the respective LED groups is controlled based on the LED driving current detection manner, thereby providing a further improved constant light output compared to the related art LED lighting device in which the sequential driving between the respective LED groups is controlled based on the LED driving voltage detection manner.

In addition, according to the present invention, the following effects can be brought about: by using the loop-back compensation section which can be double-discharged through the double discharge path, the circuit efficiency can be improved and the light amount can be increased.

Drawings

Fig. 1 is a conceptual diagram for explaining flicker performance.

Fig. 2 is a schematic block diagram of a four-step sequential driving LED lighting device according to the related art.

Fig. 3 is a waveform diagram showing a relationship between a driving voltage and an LED driving current of the LED lighting device according to the related art illustrated in fig. 2.

Fig. 4 is a schematic block diagram of an LED lighting device according to an embodiment of the present invention.

Fig. 5a to 5d are block diagrams showing the switching control states and the LED driving currents for the respective operation sections of the LED lighting device according to embodiment 1 of the present invention shown in fig. 4.

Fig. 6 is a waveform diagram illustrating a relationship of a rectified voltage by time, an LED driving current, an input current, and a light output of an LED light emitting portion of the LED lighting device according to embodiment 1 of the present invention shown in fig. 4.

Fig. 7 is a schematic block diagram of the LED lighting device according to embodiment 2 of the present invention.

Fig. 8a to 8e are block diagrams showing the switching control state and the LED driving current for each operation section of the LED lighting device according to embodiment 2 of the present invention shown in fig. 7.

Fig. 9 is a schematic block diagram of the LED lighting device according to embodiment 3 of the present invention.

Fig. 10 is a schematic block diagram of the LED lighting device according to embodiment 4 of the present invention.

Fig. 11 is a schematic block diagram of the LED lighting device according to embodiment 5 of the present invention.

Fig. 12a to 12c are block diagrams illustrating a switching control state per operation section and an LED driving current of the LED lighting device according to embodiment 5 of the present invention shown in fig. 11.

Fig. 13 is a waveform diagram illustrating a relationship among a rectified voltage by time, an LED driving current, an input current, and a light output of an LED light emitting portion according to the LED lighting device of embodiment 5 shown in fig. 11.

Fig. 14 is a schematic block diagram of the LED lighting device according to embodiment 6 of the present invention.

Fig. 15a to 15c are block diagrams showing the switching control state and the LED driving current for each operation section of the LED lighting device according to embodiment 6 of the present invention shown in fig. 14.

Fig. 16 is a waveform diagram illustrating a relationship of a rectified voltage by time, an LED driving current, an input current, and a light output of an LED light emitting portion of the LED lighting device according to embodiment 6 of the present invention illustrated in fig. 14.

Fig. 17 is a schematic block diagram of the LED lighting device according to embodiment 7 of the present invention.

Fig. 18 is a schematic block diagram of the LED lighting device according to embodiment 8 of the present invention.

Fig. 19 is a schematic block diagram of the LED lighting device according to embodiment 9 of the present invention.

Fig. 20 is a schematic block diagram of the LED lighting device according to embodiment 10 of the present invention.

Fig. 21 is a schematic block diagram of the LED lighting device according to embodiment 11 of the present invention.

Fig. 22 is a schematic block diagram of the LED lighting device according to embodiment 12 of the present invention.

Fig. 23 is a schematic block diagram of the LED lighting device according to embodiment 13 of the present invention.

Fig. 24a to 24d are block diagrams showing the configuration of the switching control state for each operation section, the driving current for each LED group, and the charging/discharging current of the Loop-back compensation unit in the LED lighting device according to the 13 th embodiment of the present invention shown in fig. 23.

Fig. 25 is a waveform diagram showing a time-wise rectified voltage, a first LED group driving current, a second LED group driving current, and a loopback compensator charging and discharging current of the LED lighting device according to embodiment 13 of the present invention shown in fig. 23.

Fig. 26 is a schematic block diagram of the LED lighting device according to embodiment 14 of the present invention.

Fig. 27 is a schematic block diagram of the LED lighting device according to embodiment 15 of the present invention.

Fig. 28 is a schematic block diagram of the LED lighting device according to embodiment 16 of the present invention.

Detailed Description

The following detailed description of the invention refers to the accompanying drawings that illustrate specific embodiments in which the invention may be practiced, by way of example. These embodiments are provided so that those skilled in the art will be fully able to practice the invention without undue experimentation. It is to be understood that the various embodiments of the invention, although different from each other, are not necessarily mutually exclusive. For example, the specific shapes, structures and characteristics described herein may be implemented according to one embodiment without departing from the technical spirit and scope of the present invention. In addition, it is to be understood that the position or arrangement of individual constituent elements within each disclosed embodiment may be modified without departing from the technical spirit and scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims, along with the full scope of equivalents to which such claims are entitled, if such description is appropriately made. Like reference symbols in the various drawings indicate like or similar functionality throughout the several views.

Hereinafter, the present invention will be described in detail with reference to preferred embodiments thereof and with reference to the accompanying drawings so that those having ordinary knowledge in the art to which the present invention pertains can easily carry out the present invention.

[ preferred embodiments of the invention ]

In the embodiment of the present invention, the term "LED group" refers to a set of LEDs in which a plurality of LEDs (or a plurality of light emitting units) are connected in series/parallel/series-parallel, and which can be controlled as one unit (i.e., lit/extinguished together) according to the control of the LED driving module.

In addition, the term "first forward voltage level V_f1"refers to a threshold voltage level capable of driving the first LED group, and the term" second forward voltage level V_f2"refers to a critical voltage level (i.e., a voltage level obtained by adding a forward voltage level of the first LED group and a forward voltage level of the second LED group) capable of driving the first LED group and the second LED group connected in series, and the term" 3 rd forward voltage level V_f3"refers to a threshold voltage level capable of driving the first to third LED groups connected through the series connection. I.e. "nth forward voltage level V_fn"refers to a threshold voltage level (i.e., a voltage level obtained by adding all of the forward voltage levels of the 1 st LED group to the forward voltage level of the nth LED group) capable of driving the first to nth LED groups connected in series.

In addition, the term "sequential driving manner based on detection of driving voltage" or "multi-step driving manner based on detection of driving voltage" refers to a driving manner in which, for an LED driving module that drives LEDs by receiving an input voltage whose magnitude varies with time, a plurality of LED groups are sequentially lighted as the received input voltage increases, and are sequentially turned off according to a decrease in the received input voltage. In addition, the term "sequential driving manner based on detection of driving voltage" or "multi-step driving manner based on detection of driving voltage" refers to a driving manner in which, for an LED driving module that drives LEDs by receiving an input voltage whose magnitude changes with time, a plurality of LED groups constituting the LED light emitting portion are sequentially turned on and off according to increase and decrease of LED driving current of the LED light emitting portion or a rectifying switch connected to the LED light emitting portion. In addition, regardless of the sensing of the driving voltage detection method or the driving current detection method, for the sequential driving method or the multi-step driving method, the first-stage operation interval refers to an operation interval in which only the first LED group emits light, the second-stage operation interval refers to an operation interval in which only the first LED group and the second LED group emit light, and the nth-stage operation interval refers to an operation interval in which all of the first LED group to the nth LED group emit light.

In addition, the term "first driving voltage" refers to a driving voltage that is supplied to the LED group at a time by the input voltage itself or by the input voltage being subjected to a predetermined process (for example, a process by a process of rectifying a current or the like). In addition, the term "second driving voltage" refers to a driving voltage secondarily supplied to the LED group by the energy storage element after the input voltage is stored to the energy storage element. Such a second drive voltage may exemplarily be: after the input voltage is stored in the capacitor, the charged capacitor supplies a driving voltage to the LED group. Accordingly, the term "driving voltage" means to include the first driving voltage and/or the second driving voltage supplied to the LED group except for the case where it is specially distinguished and referred to as "first driving voltage" or "second driving voltage".

In addition, the term "LED group driving current" refers to an LED driving current flowing through a specific LED group regardless of an operation section. For example, the first LED group driving current refers to an LED driving current flowing through the first LED group, and similarly, the nth LED group driving current refers to an LED driving current flowing through the nth LED group. The LED group drive current may vary over time.

Conversely, the term "LED drive current" refers to the drive current flowing through the LED group(s) during a particular operating interval. For example, the first LED driving current refers to an LED driving current flowing during a first operation interval, and the second LED driving current refers to an LED driving current flowing during a second operation interval. Similarly, the nth LED driving current refers to an LED driving current flowing during the nth operation interval. The LED driving current may not vary with time and be constant-current controlled to a predetermined value using a constant-current switch.

In addition, the term "first driving voltage" refers to the input voltage itself or the driving voltage that is supplied to the LED group at a time when the input voltage is subjected to a certain process (for example, a process by a constant current or the like). In addition, the "second driving voltage" refers to a driving voltage secondarily supplied to the LED group by the energy storage unit after the input voltage is stored to the energy storage unit (e.g., the loopback compensation section). Such a second driving voltage may be, for example, a driving voltage supplied to the LED group by the charged capacitor after the input voltage is stored to the capacitor. Therefore, the term "driving voltage" is intended to include the first driving voltage and/or the second driving voltage supplied to the LED group, except for the case of being particularly distinguished and referred to as "first driving voltage" or "second driving voltage".

In addition, the term "compensation section" refers to a section in which the voltage level of the input voltage (constant current voltage) is less than the preset forward voltage level, i.e., a section in which the driving current cannot be supplied to the LED group, in the sequential driving manner. For example, a first forward voltage level V_f1The compensation interval refers to the voltage level of the constant current voltage being less than V_f1The interval of (2). In this case, the compensation interval is a non-emission interval. In addition, a second forward voltage level V_f2The compensation interval indicates that the voltage level is less than V_f2The interval of (2). Accordingly, the nth forward voltage level V_fnVoltage level of less than V representing rectified voltage_fnThe interval of (2). In addition, the term first forward voltage level V_f1The compensation interval means a driving current supplied to the LED group by supplying a second driving voltage to the LED group within the compensation interval of the first forward voltage level Vf1, and the term second forward voltage level V_f2By compensated is meant at a second forward voltage level V_f2And supplying a second driving voltage to the LED group in the compensation interval. Thus, the nth forward voltage level Vfn compensation refers to the nth forward voltage level V_fnAnd supplying a second driving voltage to the LED group in the compensation interval.

In addition, the term "first compensation region" refers to a region in which the energy storage unit supplies the second driving voltage to the LED group(s) at a time, and "second compensation regionThe interval "refers to an interval in which the energy storage unit secondarily supplies the second driving voltage to the LED group(s). For example, for the present invention, the loopback compensation section may supply the second to nth LED groups with the second driving voltage once in the second forward voltage level compensation section, and supply the second driving voltage once at the first forward voltage level V_f1The second driving voltage may be secondarily supplied to the first to nth LED groups within the compensation interval. In this case, the first compensation interval refers to a voltage level of the rectified voltage being less than V_f2The second compensation interval refers to a voltage level of the rectified voltage being less than V_f1The interval of (2). The first compensation interval and the second compensation interval may be variously modified according to the design of the LED driving circuit, and thus should not be interpreted as an absolute meaning.

In addition, the term "one LED group" refers to the LED group(s) that obtain the second driving voltage through the same amplification path (circuit) within a specific compensation interval.

In addition, the term "non-compensation section (normal operation section)" refers to a section in which the process of supplying the second driving voltage by the loop-back compensation section is not performed, and the term "charging section" refers to a section in which the loop-back compensation section performs charging. The non-compensation interval and the charging interval may be the same, or the charging interval may be a part of the non-compensation interval.

In the present specification, V used to indicate a specific voltage, a specific time point, and a specific temperature₁、V₂、V₃、……、t₁、t₂、……、T₁、T₂、T₃The terms are not used to represent absolute values but relative values used to distinguish them from each other.

Configuration and function of embodiment 1 of LED lighting device 1000

Fig. 4 is a schematic block diagram of an LED lighting device (hereinafter, referred to as "LED lighting device") having improved flicker performance according to embodiment 1 of the present invention. The structure and function of the LED lighting device 1000 according to the present invention will be briefly examined below with reference to fig. 4.

First, a general technical idea of the LED lighting device 1000 according to the present invention will be considered. As described above, in the ac LED lighting device of the sequential driving system according to the related art, the LED groups are sequentially turned on and off according to the voltage level of the driving voltage supplied to the LED light emitting unit 20, and thus the voltage level of the driving voltage is less than the first forward voltage level V_f1A non-emission interval occurs in which none of the LED groups emits light. In addition, in the ac LED lighting device of the sequential driving method according to the related art, the number of LEDs to be lit increases as the voltage level of the driving voltage supplied to the LED light emitting unit 20 increases, and the number of LEDs to be lit decreases as the voltage level of the driving voltage supplied to the LED light emitting unit 400 decreases. Due to the above-mentioned characteristics of the ac LED lighting device of the sequential driving system, there is a problem that the flicker performance is very poor.

Therefore, the most basic technical idea according to the present invention is: the flickering performance of the LED lighting device 1000 is improved by eliminating a non-emission section, which is a section where the LED light emitting section 400 of the LED lighting device 1000 does not emit light during the operation of the LED lighting device 1000. In order to perform the above functions, the present invention proposes a compensation part in a loop back (loop back) mode, and the loop back compensation part 300 supplies a second driving voltage to the LED light emitting part 400 in a non-light emitting interval, thereby eliminating the non-light emitting interval.

In addition, in relation to the flicker performance as described above, the reason why the flicker performance is poor in the ac LED lighting device of the sequential driving system is that the LED driving current is controlled in proportion to the number of LEDs to be lit for each operation section. In order to solve the above-described problems, the present invention proposes an LED lighting device configured to control an LED driving current for each operation section in inverse proportion to the number of LEDs to be lit for each operation section. Therefore, according to the present invention, the LED driving current control method described above is adopted, and in the case where the number of LEDs to be lit up according to the operation section is relatively small, it is possible to make the LED driving current during the operation section relatively larger by the control, and in the case where the number of LEDs to be lit up is relatively larger, it is possible to make the LED driving current during the operation section relatively smaller by the control, so that it is possible to provide almost uniform light output per operation section. The LED driving current control method according to the present invention will be described below with reference to fig. 5a to 5d and fig. 6.

First, as shown in fig. 4, the LED lighting device 1000 according to the present invention may include a rectifying part 200, a loopback compensating part 300, an LED light emitting part 400, and an LED driving control part 500. In addition, in the above-described configuration elements, the loopback compensating section 300 and the LED driving control section 500 may constitute a driving circuit.

First, the light emitting unit 400 may be configured by a plurality of LED groups, and the plurality of LED groups included in the LED light emitting unit 400 may sequentially emit light and sequentially turn off according to the control of the LED driving control unit 500. Although fig. 4 discloses one LED light emitting unit 400 including the first LED group 410 and the second LED group 420, those skilled in the art will appreciate that the number of LED groups included in the LED light emitting unit 400 can be variously changed as needed. Hereinafter, for convenience of explanation and understanding, an example in which the light emitting part 400 of the LED is configured by two LED groups will be explained as a standard, but the present invention is not limited thereto. For example, the LED lighting unit 400 may be configured by four LED groups from the first LED group 410 to the fourth LED group (not shown), or may be configured by n LED groups from the first LED group 410 to the nth LED group (not shown), but those skilled in the art can understand that the LED lighting unit falls within the scope of the claims of the present invention as long as the technical spirit of the present invention is fully included.

In addition, according to the configuration of the embodiment, the first LED group 410 and the second LED group 420 may have different forward voltage levels from each other. For example, in the case where the first LED group 410 and the second LED group 420 respectively include LED elements of mutually different numbers, or in the case where the first LED group 410 and the second LED group 420 have series or parallel or series-parallel connection relationships in mutually different manners, the first LED group 410 and the second LED group 420 may have mutually different forward voltage levels. However, it is to the inventionFor the preferred embodiment, the design of the first LED group 410 needs to satisfy: has a forward voltage level that can be driven by the second driving voltage supplied from the loopback compensation section 300 within the compensation interval. According to an exemplary embodiment, the first LED group 410 may be configured such that: enabling the peak value V of the rectified voltage_{rec_peak}More than twice the forward voltage level of the first LED group 410. In addition, according to an exemplary embodiment, the first LED group 410 and the second LED group 420 may be configured such that: the forward voltage level of the first LED group 410 can be made equal to or less than the forward voltage level of the second LED group 420. Designed by the above design, the first LED group 410 is at the ac voltage V_ACMay remain lit throughout the entire cycle.

In addition, for other exemplary embodiments, in order to improve the flicker performance as described above, it is preferable to realize by design: AC voltage V_ACThe number of the first LED group 410 configuration LEDs which are kept in a lit state throughout the entire interval is larger than the number of the second LED group 420 configuration LEDs which emit light only during the second operation interval. Accordingly, in this case, it is possible to satisfy by design: the forward voltage level of the first LED group 410 is significantly greater than the forward voltage level of the second LED group 420.

The rectifying portion 200 according to the present invention as shown in fig. 4 is configured in the following manner: for AC voltage V received from external power supply_ACRectifies the voltage to generate and output a rectified voltage V_rec. As the rectifying unit 200, one of various known rectifying circuits such as a full-wave rectifying circuit and a half-wave rectifying circuit can be used. The rectifying unit 200 is configured as follows: will generate a rectified voltage V_recThe feedback signal is supplied to the loop-back compensation unit 300, the LED light emitting unit 400, and the LED drive control unit 500. In FIG. 4, a diode D consisting of 4 diodes is shown₁、D₂、D₃、D₄The bridge full-wave rectifying circuit is formed.

In addition, the loopback compensation part 300 according to the present invention is configured in the following manner: the energy is charged by using the rectified voltage Vrec in the charging interval, and the LED light emitting unit 400 can be supplied with the energy in the compensation intervalA second driving voltage. In FIG. 4, the first capacitor C is shown₁The loopback compensation part 300 according to the present invention is illustrated. However, the present invention is not limited thereto, and one of various known compensation circuits (e.g., valley fill) may be used as needed.

In addition, as shown in fig. 5, one end of the loop-back compensation part 300 is connected to the positive terminal of the first LED group 410, and the other end of the loop-back compensation part 300 passes through the third constant current switch SW₃And is connected to the LED driving control part 500. Of course, according to the configuration of the embodiment, one end of the loopback compensating part 300 may also be connected to the positive terminal of other LED group. For example, in the embodiment in which the LED light emitting unit 400 is constituted by 4LED groups, the configuration can satisfy: one end of the loopback compensating part 300 can be connected to the positive terminal of the second LED group. In this case, the loop-back compensation section 300 may be configured to satisfy: the second driving voltage can be supplied to the second LED group (or the second to third LED groups, etc.) within the compensation interval. Hereinafter, an embodiment in which one end of the loop-back compensation unit 300 is connected to the positive terminal of the first LED group 410 and the second driving voltage can be supplied to the first LED group 410 in the compensation interval will be described.

In addition, for the embodiment shown in fig. 4, the loopback compensation section 300 according to the present invention is constructed in the following manner: in the second operating interval (i.e. the rectified voltage V)_recIs a second forward voltage level V_f2The above interval) and in the non-emission interval (i.e., the rectified voltage V)_recIs less than a first forward voltage level V_f1During the period) to supply the second driving voltage to the first LED group 410. However, the present invention is not limited to the embodiment, and in the case that the LED illumination device 1000 according to the present invention includes 4LED groups of the first to fourth LED groups 410 to (not shown), the loopback compensation part 300 may also be in the fourth operation interval (i.e., the rectified voltage V)_recIs a fourth forward voltage level V_f4The above interval) is charged. Further, similarly, the LED lighting device 1000 according to the present invention includes the first to nth LED groups 410 to (not shown)Illustrated) of n LED groups, it should be noted that the loopback compensation section 300 may also be in the nth operation interval (i.e., the rectified voltage V)_recIs the nth forward voltage level V_fnThe above interval) is charged.

In addition, the forward voltage level compensated by the loopback compensation part 300 according to the present invention may be according to an energy charging and discharging unit (e.g., the first capacitor C of fig. 4) constituting the loopback compensation part 300₁Etc.) are designed in various forms. For one embodiment, the loop-back compensation part 300 according to the present invention may be configured to satisfy: a voltage level of one-half (1/2) of the total forward voltage level (voltage level resulting from adding the forward voltage levels of all LED groups) can be compensated. Therefore, for the embodiment in which the forward voltage level of the first LED group 410 is designed to be the following to the forward voltage level of the second LED group 420, the configuration of the loopback compensation part 300 according to the present invention may satisfy: capable of supplying a first forward voltage level V within a compensation interval_f1The voltage of (c). In this case, as described above, the first LED group 410 may be always maintained in the closed state regardless of the period of the ac power.

In addition, contrary to the configuration according to the related art as shown in fig. 2 that may satisfy the LED driving control part 500 capable of controlling sequential driving between a plurality of LED groups by the driving voltage detection method, the configuration of the LED driving control part 500 according to the present invention may satisfy: LED drive current I capable of detecting LED light emitting section 400_LEDOr constant current switch(s) SW connected to the LED light emitting section 400₁～SW₃LED drive current I_LEDAnd based on the detected LED drive current I_LEDTo control the sequential driving of the first LED set 410 and the second LED set 420. However, it should be noted that the present invention is also applicable to an LED lighting device capable of controlling sequential driving between a plurality of LED groups using a driving voltage detection method.

More specifically, for the LED lighting device according to the present invention, the LED driving control part 500 according to the present invention may include the first constant current switch S for the control of sequential driving by the driving current detection method as described aboveW₁A second constant current switch SW₂And a third constant current switch SW₃. The first constant current switch SW is shown in fig. 4₁To a third constant current switch SW₃The embodiment is embodied outside the LED driving control part 500 as an independent switch, but the first constant current switch SW may be clearly understood by those skilled in the art₁To a third constant current switch SW₃May be included in the LED driving control part 500.

In addition, the first constant current switch SW according to the present invention₁To a third constant current switch SW₃Each of the configurations can satisfy the following functions: the LED driving control unit 500 closes the current path by controlling the LED driving control unit to connect the current path or opens the current path to separate the current path, and detects the LED driving current I flowing through the connected current path_LEDThereby driving the LED with a current I_LEDThe constant current control is a preset value. More specifically, as shown in fig. 4, the first constant current switch SW₁Between a node between the first and

second LED groups

410 and 420 and the LED driving control part 500, so that connection of the first current path P according to control of the LED driving control part 500 can be performed₁Or to separate the first current path P₁The function of (c). Similarly, a second constant current switch SW₂Between the second LED group 420 and the LED driving control part 500, thereby performing control of the second current path P according to the LED driving control part 500₂Performing a connecting or disconnecting function. In addition, a third constant current switch SW₃Between the loop-back compensation part 300 and the LED driving control part 500, thereby performing connection or separation of the third current path P according to the control of the LED driving control part 500₃The function of (c). For the present invention, the first constant current switch SW according to the present invention as described above₁To a third constant current switch SW₃And may be implemented using a variety of well-known techniques. For example, in association with the constant current control function as described above, the first constant current switch SW according to the present invention₁To a third constant current switch SW₃Respectively controlling: the detection resistor is used for detecting current; an automatic amplifier for comparing the standard current value with the current detected current value; a switch unit according toThe output of the automatic amplifier controls the connection of the path, and when the path is connected, the LED driving current value passing through the path can be controlled to be constant current. In addition, as an example, the first constant current switch SW is constituted according to the present invention₁To a third constant current switch SW₃The switching unit of (a) may be implemented with one of the following units: a Metal Oxide Semiconductor Field Effect Transistor (MOSFET); an Insulated Gate Bipolar Transistor (IGBT); a Bipolar Junction Transistor (BJT); a Junction Field Effect Transistor (JFET); a thyristor (Silicon controlled recifier); a Triac (Triac).

The LED driving control section 500 of the present invention shown in fig. 4 is configured as follows: detecting LED drive current I_LEDAccording to the detected LED drive current I_LEDTo control the first constant current switch SW as described above₁To a third constant current switch SW₃Thereby controlling sequential driving of the first LED group 410 and the second LED group 420. The detailed functions of such an LED driving control unit 500 will be specifically discussed below with reference to fig. 5 to 6.

Fig. 5a to 5d are block diagrams illustrating the switching control state and the LED driving current for each operation section of the LED lighting device according to embodiment 1 of the present invention shown in fig. 4. Hereinafter, the operation of the LED lighting device 1000 according to embodiment 1 of the present invention shown in fig. 4 will be discussed in detail with reference to fig. 5a to 5 d.

First, fig. 5a illustrates the first constant current switch SW during the first operation section₁To a third constant current switch SW₃Control state of and LED driving current I_LEDThe relationship between them. As shown in fig. 5, during the first operation interval, the first constant current switch SW₁And a second constant current switch SW₂Is in a closed state, and the third constant current switch SW₃Is in an off state. With the LED lighting device according to the present invention, the driving voltage supplied to the LED light emitting section (the first driving voltage (rectified voltage V) supplied by the rectifying section in the non-compensation section_rec) The second driving voltage provided by the loop-back compensation part 300 in the compensation interval) is the first LED group410, i.e., a point of time above the first forward voltage level, starts to flow the LED driving current I within the first LED group 410_LEDAccordingly, the first LED group 410 is lit. At this time, the LED driving current I flowing through the first LED group 410_LEDIs switched by the first constant current₁The constant current is controlled to be a preset first LED driving current I_LED1The value of (c).

Next, fig. 5b illustrates the first constant current switch SW during the second operation interval₁To a third constant current switch SW₃Control state of and LED driving current I_LEDThe relationship (2) of (c). In the state illustrated in fig. 5a, the driving voltage supplied from the LED light emitting part 400 continuously rises to a voltage level obtained by adding the forward voltage level of the first LED group 410 and the forward voltage level of the second LED group 420, that is, a second forward voltage level V_f2At the above time point, the second LED set 420 also starts to be powered on, and the second LED set 420 is also turned on. As described above, during the first operation interval, the second current path P is used to pass the second LED set 420₂And a second constant current switch SW connected to the LED driving control part 500₂Is in a closed state, and accordingly can detect the passage of the second constant current switch SW₂While the flowing LED drives the current I_LED. The LED driving control part 500 detects the passing of the second constant current switch SW₂While the flowing LED drives the current I_LEDAnd is judged to pass through the second constant current switch SW₂While the flowing LED drives the current I_LEDWhether or not an excessive state (a state of current rise and/or fall) is experienced while normally maintaining a constant current state. Through the second constant current switch SW₂While the flowing LED drives the current I_LEDIn the case of maintaining a normal constant current state, i.e. at a predetermined second LED drive current I_LED2When the value is stably maintained, the LED driving control unit 500 determines that the driving voltage supplied to the LED light emitting unit 400 is sufficient to drive the first LED group 410 and the second LED group 420 (i.e., determines that the voltage level of the driving voltage is equal to or higher than the second forward voltage level), and turns off the first constant current switch SW₁And entering a second operation interval. At the same time, LED drive controlThe control part 500 closes the third constant current switch SW₃And is connected to the third current path P₃And starts to detect through the third constant current switch SW₃And the flowing loop-back compensation part charging current I_c. First constant current switch SW at a point of time of entering a second operation section₁And a second constant current switch SW₂Control state of and LED driving current I_LEDIs shown in fig. 5 b.

In addition, the second LED group 420 emits light together with the first LED group 410 during the second operation interval described above, and thus the number of LEDs emitting light during the second operation interval is increased compared to the first operation interval. Therefore, in order to be able to keep the light output of the LED light emitting unit 400 substantially constant during the first and second operation intervals, the second LED driving current I_LED2Can be set lower than the first LED drive current I_LED1The value of (c). More preferably, the second LED drive current I_LED2And a first LED drive current I_LED1The relationship therebetween may be set to satisfy: the light output per operation interval can be almost the same by establishing an inverse relationship with the number of LEDs emitting light per operation interval.

Next, FIG. 5c illustrates the first constant current switch SW₁To a third constant current switch SW₃Control state of and LED driving current I_LEDThe relationship between them. As shown in fig. 5b, the LED driving control part 500 detects the charging current I during the second operation interval_cThen, the LED driving control unit 500 gradually increases the rectified voltage to the charging current I_cThe second constant current switch SW is turned off at a point of time when a predetermined value set in advance is reached₂Thereby entering a charging interval. The block diagram of the above state is shown in fig. 5 c. As shown in fig. 5c, the second constant current switch SW in the charging interval₂Is in an off state, and therefore, the third LED drives a current I_LED3Through a third current path P₃And flows through the first LED set 410 and the loopback compensating part 300. Therefore, during the charging interval, only the first LED set emits light, and the second LED set 420 is turned off. The LED driving control part 500 sequentially detects the passing of the third current path P in the charging interval₃While the flowing third LED drives the current I_LED3。

In addition, at the rectified voltage V_recAfter reaching the maximum voltage level, gradually decreases to pass through the third current path P₃Third LED drive current I_LED3When the current level drops below the predetermined value, the LED driving control unit 500 controls the first constant current switch SW in the state shown in fig. 5b₁To a third constant current switch SW₃Thereby resuming the second operation interval. That is, the LED driving control part 500 turns off the third constant current switch SW₃And closing the second constant current switch SW₂. Therefore, as described above, during the second operation interval, the first LED set 410 and the second LED set emit light, and the LED driving current I is applied at the same time_LEDIs controlled by constant current to be a second LED driving current I_LED2The value is obtained.

When the constant current voltage is continuously reduced to be less than a second forward voltage level V_f2At this time, the LED driving control part 400 controls the first constant current switch SW in the state illustrated in fig. 5b₁To a third constant current switch SW₃Thereby restoring to the first operating interval. As described above, only the first LED group 410 is illuminated during the first operation interval, while the second LED group 420 is extinguished. In addition, at this time, the LED drives the current I_LEDIs controlled by constant current to be a first LED driving current I_LED1The value is obtained.

Then, at the rectified voltage V_recReduced to less than a first forward voltage level V_f1At this time, the LED driving control part 500 controls the first to third constant current switches SW1 to SW3 in the state shown in fig. 5d, thereby entering the compensation section. As can be seen from comparing fig. 5a and 5d, the control state of the constant current switch of fig. 5a is the same as the control state of the constant current switch of fig. 5 d. Therefore, basically, the control of the constant current switch may not occur, which naturally supplies the second driving voltage from the loop-back compensation section 300 to the first LED light emitting section 400 only due to the potential difference. Accordingly, during the compensation interval, the second driving voltage may be provided from the loopback compensation part 300 to the first LED group 410, and accordingly, the fourth LED driving current I may flow through the first current path_LED4And the lighting state of the first LED group 410 is maintained. At this timeFourth LE D drive current I_LED4Can be substantially equal to the first LED drive current I_LED1The same is true.

As described above, the rectified voltage V_recSequentially performing control of the first operation interval, the second operation interval, the charging interval, the second operation interval, the first operation interval, and the compensation interval in one period to obtain a rectified voltage V_recPeriodically repeating the above-described control for each cycle.

Fig. 6 is a waveform diagram illustrating a relationship of a rectified voltage by time, an LED driving current, an input current, and a light output of an LED light emitting portion of the LED lighting device according to embodiment 1 of the present invention as illustrated in fig. 4. FIG. 6 (a) shows the rectified voltage V as a function of time_recFig. 6 (b) shows the LED drive current I varying with time_LEDAnd (c) of fig. 6 shows a time-varying slave ac power supply V_acInput current I to LED lighting device_inFig. 6 (d) shows a waveform of light output of the LED light emitting unit 400 varying with time.

Referring to fig. 6, if the LED lighting device 1000 starts to be started first, the LED light emitting section 400 cannot emit light because the loopback compensating section 300 is not charged. The first LED group 410 is at the rectified voltage V_recReaches a first forward voltage level V with the passage of time_f1Is lit up at the time point (2). And the state diagram at this time is shown in fig. 5 a.

At rectified voltage V_recContinues to rise to a second forward voltage level V_f2When (t)₂) The LED driving control part 500 turns on the second constant current switch SW₂And a third constant current switch SW₃And turns off the first constant current switch SW₁Thereby entering a second operation interval. This state is illustrated in fig. 5 b. In the second operation interval, the first LED group and the second LED group 420 are both lit, and as described above, the second LED driving current I during the second operation interval_LED2Is preferably set lower than the first LED driving current I_LED1Is controlled by a constant current. Of course, the first LED driving circuit is clearly understood by those skilled in the artStream I_LED1And a second LED drive current I_LED2May be set to the same value as required. Also according to an embodiment, the second LED drive current I_LED2Can be set higher than the first LED drive current I_LED1The value of (c). Therefore, as shown in fig. 6 (d), the light output of the LED light emitting unit 400 during the second operation interval can be almost the same as the light output of the LED light emitting unit 400 during the first operation interval. In addition, as described above, during the second operation interval, the LED driving control part 500 is in the state of continuously detecting whether to pass through the third constant current switch SW₃While a charging current I flows_cThe state of (1).

At rectified voltage V_recContinues to rise to stably supply the charging current I to the loopback compensating part 300_cTime point of (t)₃) The LED driving control part 500 turns off the second constant current switch SW₂And enters the charging interval. As shown in fig. 5c, only the first LED group 410 emits light in the above-mentioned charging interval, and the loopback compensation part 300 is charged. At this time, the LED driving current I passes through the first LED group 410 and the loopback compensating part 300_LEDCan be controlled by constant current as controlled by a third constant current switch SW₃To a preset third LED driving current value I_LED3Also according to an embodiment, the first LED drive current I_LED1Value and third LED drive current I_LED3The values of (b) may be set to the same values. The purpose is to reduce the light output deviation per operation interval.

At the arrival of the rectified voltage V_recIs lowered by the highest point and reaches a time point (t) at which the charging current cannot be stably supplied to the loopback compensating part 300₄) The LED driving control part 500 closes the second constant current switch SW as shown in fig. 5b₂Thereby entering a second operation interval.

Then, at the rectified voltage V_recTo less than a second forward voltage level V_f2When (t)₅) The LED driving control part 500 closes the first constant current switch SW as shown in fig. 5a₁And turns off the third constant current switch SW₃Thereby entering the first operation interval. At this time, the LED is drivenThe control part 500 detects the second LED driving current I_LED2To determine the rectified voltage V_recIs less than a second forward voltage level V_f2. Namely, the constitution can satisfy: at the detected second LED drive current I_LED2When the voltage drops below a predetermined value, it can be judged as the rectified voltage V_recIs less than the second forward voltage level.

At rectified voltage V_recContinues to drop below the first forward voltage level V_f1When (t)₆) The second driving voltage may be supplied from the loopback compensation part 300 to the first LED group 410 as shown in fig. 5d, so that the first LED group 410 may emit light. As described above, the control may not be performed on the constant current switch individually at the above-described time point, but the process of discharging from the loopback compensation part 300 to the first LED group 410 may be naturally performed by the potential difference.

At rectified voltage V_recIs re-raised to the first forward voltage level V_f1Above (t)₈) The first LED set 410 may be re-operated according to the rectified voltage V as shown in fig. 5a_recSo that the process of emitting light is performed. The sequential control process as described above is at the rectified voltage V_recEach cycle of (a) is repeated periodically.

In addition, as can be seen from fig. 6 (d), the LED light emitting unit 400 is operated at the rectified voltage V_recMaintaining a constant light output throughout the interval. This is achieved by driving the second LED with a second LED drive current I during a second interval of operation_LED2Controlled to be lower than a first LED drive current I_LED1The value of (a) to (b).

Although the embodiment in which the LED light emitting unit 400 is composed of two LED groups, i.e., the first LED group 410 and the second LED group 420, has been described above for convenience of description and illustration, it will be apparent to those skilled in the art that the same method can be applied to the embodiment in which the LED light emitting unit 400 is composed of 3 or 4 or more LED groups, and the embodiment described above is within the scope of the claims of the present invention.

LED lighting device 100Configuration and function of embodiment 2 of 0

Fig. 7 is a schematic block diagram of the LED lighting device according to embodiment 2 of the present invention, and fig. 8a to 8e are block diagrams showing the switching control state and the LED driving current for each operation section of the LED lighting device according to embodiment 2 of the present invention shown in fig. 7. The structure and function of the LED lighting device 1000 according to embodiment 2 of the present invention will be discussed in detail below with reference to fig. 7 and 8a to 8 e.

The LED lighting device 1000 according to embodiment 2 of the present invention as shown in fig. 7 is provided with a fourth switch SW between the loop-back compensation part 300 and the node between the first LED group 410 and the second LED group 420₄Except for the points, the configuration is similar to that of the LED illumination device 1000 according to embodiment 1 shown in fig. 4. Therefore, the repeated configuration and functions can be referred to the description of fig. 4, and the following discusses the LED lighting device 1000 according to embodiment 2 of the present invention mainly based on the differences from embodiment 1.

First, the fourth switch SW shown in FIG. 7₄It is possible to finely control the charge and discharge process of the loopback compensator 300 according to the control of the drive controller 500.

Specifically, within the first operation interval, the fourth switch SW₄The off state is maintained as shown in fig. 8 a. Therefore, the current does not flow to the loopback compensation section 300 within the first operation interval.

Next, as shown in FIG. 8b, a fourth switch SW₄Is closed at a point of time of entering the second operation section, thereby connecting the current path between the rectifying section 200 and the loopback compensating section 300, and the charging current I_cMay flow to the loopback compensation part 300 through the above-described current path.

Next, as shown in FIG. 8c, a fourth switch SW₄The closed state may be maintained at a time point of entering the charging interval, so that the loopback compensating part 300 may pass the charging current I_cAnd (6) charging.

Further, a fourth switch SW₄At the time of entering the second operation interval from the charging intervalThe closed state is also maintained as shown in fig. 8 b. Then, at a point of time when the first operation section is entered from the second operation section, the fourth switch SW₄Broken as shown in fig. 8 a.

In addition, at the rectified voltage V_recTo a voltage level less than a first forward voltage level V_f1At this time, the LED lighting device 1000 according to embodiment 2 enters the compensation interval. Within the compensation interval, the fourth switch SW₄The off state is also maintained. Fig. 8d and 8e illustrate the first constant current switch SW in the LED lighting device 1000 during the compensation interval₁To a fourth switch SW₄The control state of (2).

It is to be noted that the loopback compensation section 300 according to embodiment 2 of the present invention can compensate for both the second operation interval and the first operation interval differently from embodiment 1. More specifically, at V of the rectified voltage_recTo a first forward voltage level V_f1At this time, the second driving voltage is supplied from the loopback compensating part 300 to the first LED group 410 and the second LED group 420 due to the potential difference. Therefore, at this time, as shown in fig. 8d, the first constant current switch SW₁Off and the second constant current switch SW₂The closed state is maintained. At this time, a fourth LED driving current I flows_LED4And the fourth LED drives a current I_LED4Is constant-current controlled to a predetermined value by the second constant-current switch SW 2. Fourth LED drive current I_LED4Can be set to the second LED drive current I_LED2The same value.

In addition, as time passes, the second driving voltage supplied by the loopback compensating section 300 drops to be less than the second forward voltage level V_f2While, the fourth LED drives the current I_LED4May fall below a predetermined value, and at the above-mentioned time point, the LED driving control part 500 closes the first constant current switch SW₁. Therefore, during the above-mentioned interval, only the first LED set 410 emits light, and the fifth LED driving current I flows at this time_LED5By a first constant current switch SW₁The constant current is controlled to a predetermined value. Fifth LED drive Current I_LED5Can be set to drive with the first LEDCurrent I_LED1The same value.

When the rectified voltage V is reached again_recRises to a first forward voltage level V_f1At time (2), the LED lighting device 1000 is in the state of fig. 8 a. As described above, the control state of the constant current switch in the last compensation interval is the same as the control state of the constant current switch in the first driving interval, and thus it is not necessary to separately control the constant current switch.

Configuration and function of embodiment 3 of LED lighting device 1000

Fig. 9 is a schematic block diagram of the LED lighting device according to embodiment 3 of the present invention. The structure and function of the LED lighting device according to embodiment 3 of the present invention will be discussed in detail with reference to fig. 9.

The LED illumination device 1000 according to embodiment 3 of the present invention shown in fig. 9 is similar in configuration to the LED illumination device 1000 according to embodiment 1 shown in fig. 4, except for the point that the second compensation part 310 is provided in parallel with the second LED group 420. Therefore, the repeated configuration and functions can be referred to the description of fig. 4, and the following discusses the LED lighting device 1000 according to embodiment 3 of the present invention mainly based on the differences from embodiment 1.

As shown in fig. 9, the second compensation part 310 according to the present invention may be formed of a second capacitor C₂However, the present invention is not limited thereto, and various electrical charging and discharging units and/or electrical charging and discharging circuits may be used. The second compensation part 310 performs charging during the second operation interval as described above, and can perform a function of supplying the second driving voltage to the second LED group 420 during an operation interval other than the second operation interval (i.e., an operation interval in which the second LED group 420 is turned off). Accordingly, in the case of embodiment 3 shown in fig. 9, the penetration rectification voltage V_recThe first LED group 410 and the second LED group 420 may be kept in the lighting state all the time.

Configuration and function of embodiment 4 of LED lighting device 1000

Fig. 10 is a schematic block diagram of the LED lighting device according to embodiment 4 of the present invention. The structure and function of the LED lighting device according to embodiment 4 of the present invention will be discussed in detail with reference to fig. 10.

The LED illumination device according to embodiment 4 of the present invention as shown in fig. 10 may further include: a first LED drive current setting unit 610 for setting the first LED drive current I_LED1Setting the value as required; a second LED drive current setting unit 620 for setting the second LED drive current I_LED2Setting the value as required; a third LED drive current setting unit 630 for setting the third LED drive current I_LED3Set to the desired value. Except for these points, it is similar in construction to the LED illumination device according to embodiment 1 illustrated in fig. 4. Therefore, the repeated configuration and functions can be referred to the description of fig. 4, and the following discusses the LED lighting device 1000 according to embodiment 4 of the present invention mainly based on the differences from embodiment 1.

In the lighting device 1000 according to the related art described with reference to fig. 2 and 3, there is a case where the first LED driving current I cannot be set individually_LED1A second LED drive current I_LED2A third LED drive current I_LED3Fourth LED drive current I_LED4The problem of (2). That is, the LED lighting device 1000 according to the conventional art has a step-wave form, and can control the LED driving current I for each operation section_LEDThus, in general, it is possible to set an LED drive current (e.g., a fourth LED drive current I)_LED4) And controlling other LED driving intervals according to the set ratio of the LED driving current. For example, by driving a third LED with a current I_LED3Set as the fourth LED drive current I_LED480-90%, drive the second LED with a current I_LED2Set as the fourth LED drive current I_LED465-80% of the first LED and driving the first LED with a current I_LED1Set as the fourth LED drive current I_LED430 to 65% of the above. However, such an LED illumination device 100 according to the related art has a problem that each cannot be set only individuallyIndividual LED drive current I_LEDThe difficulty of (2) is, in particular, that the LED driving current is arbitrarily set for each operation interval, instead of being adjusted in proportion as described above, in order to improve flicker performance. Therefore, the LED lighting device 1000 according to embodiment 4 of the present invention is provided with the first LED driving current setting unit 610, the second LED driving current setting unit 620, and the third LED driving current setting unit independently from each other, so that the respective LED driving currents can be set as required. Fig. 10 illustrates an embodiment in which the first LED driving current setting part 610, the second LED driving current setting part 620, and the third LED driving current setting part 630 are respectively implemented by using variable resistors, but those skilled in the art can clearly understand that the driving current setting part may be implemented by other suitable units (e.g., capacitors, etc.) or other suitable circuits.

Structure and function of embodiment 5 of LED lighting device 1000

Fig. 11 is a schematic block diagram of the LED lighting device according to embodiment 5 of the present invention, and fig. 12a to 12c are block diagrams of the switching control state and the LED driving current for each operation section of the LED lighting device according to embodiment 5 of the present invention shown in fig. 11. Fig. 13 is a waveform diagram showing a relationship among the time-dependent rectified voltage, the LED driving current, the input current, and the light output of the LED light emitting unit in the LED lighting device according to embodiment 5 of the present invention shown in fig. 11. The structure and function of the LED lighting device 1000 according to embodiment 5 of the present invention will be discussed in detail below with reference to fig. 11 to 13.

First, the LED illumination device 100 according to the 5 th embodiment of the present invention has a similar aspect in the point of performing the 2-step operation as the LED illumination device 1000 of the 1 st to 4 th embodiments as described above, however, it has a difference in the point of performing the modified sequential driving without performing the sequential driving. In general, "sequentially driven" means at a rectified voltage V_recIs based on the rectified voltage V_recAccording to the voltage level of "The driving method of the operation section is changed in the order of 1-step operation section (discharge section) → 1-step operation section (non-compensation section) → 2-step operation section (charge section) → 1-step operation section (non-compensation section) → 1-step operation section (discharge section) ". In contrast, the LED illumination device 1000 according to embodiment 5 of the present invention rectifies the voltage V_recThe period of (2) is a standard, and the operation interval is changed in the order of "2-step operation interval (discharge interval) → 2-step operation interval (non-compensation interval) → 1-step operation interval (charge interval) → 2-step operation interval (non-compensation interval) → 2-unit operation interval (discharge interval)" according to the voltage level of the rectified voltage, and this is referred to as a deformed sequential driving method. That is, more LED groups emit light in a relatively low voltage level interval, and less LED groups emit light in a relatively high voltage level interval, while the loopback compensation part 300 performs charging. In addition, with the embodiment described above, the charging interval entry voltage level V, which is the standard of the entry and exit from the charging interval, is set to be the voltage level V_chargeHigher than the second forward voltage level V_f2. For the above-described embodiment, the loopback compensation section 300 may be selected to perform compensation for the second forward voltage level. That is, the capacity of the loopback compensating part 300 may be determined to supply the second driving voltage to the first LED group 410 and the second LED group 420 within the compensation interval.

For the LED lighting device according to the 5 th embodiment of the present invention, in order to perform the functions as described above, the loopback compensation part 300 may be located between the node between the first LED group 410 and the second LED group 420 and the first constant current switch SW as shown in fig. 11₁Thereby being charged during the 1-step operation interval and supplying the third LED driving current I to the first LED group 410 and the second LED group 420 through the discharge path in the non-compensation interval_LED3。

In addition, in order to perform the functions as described above, the LED driving control part 500 according to embodiment 5 of the present invention according to the rectified voltage V_recTo control the first constant current switch SW₁And a second constant current switch SW₂Thereby, the sequential driving of the first LED group 410 and the second LED group 420 can be controlled. On the upper partThe pair of first constant current switches SW₁And a second constant current switch SW₂The control of (b) may be performed based on one of the driving voltage detection manner or the driving current detection manner as described above. Hereinafter, a driving control process of the LED lighting device 1000 according to embodiment 5 of the present invention will be specifically discussed with reference to fig. 12a to 12c and fig. 13.

First, at the time point when the LED illumination device 100 according to embodiment 5 of the present invention is activated, as shown in fig. 12a, the second constant current switch SW₂In a closed state, a first constant current switch SW₁Is in an off state. When the LED lighting device 1000 is started, as shown in fig. 13, the rectified voltage V is applied_recReaches a second forward voltage level V_f2Without the LED drive current flowing before, from the rectified voltage V_recAt the point in time t when the voltage level of (2) reaches the second forward voltage level₁Starts to pass through the second current path P₂While a second LED drive current I flows_LED2. The above state diagram is shown in fig. 12 a. At this time, the LED driving current I flowing through the first LED group 410 and the second LED group 420_LEDCan be switched by a second constant current switch SW₂The constant current is controlled to be a preset second LED driving current I_LED2The value of (c).

As shown in fig. 13, when the voltage level rises with the elapse of time and reaches the charging section, the voltage level V is entered_chargeWhen (t)₂) The LED driving control part 500 turns off the second constant current switch SW₂And closing the first constant current switch SW₁Thereby entering a charging interval. In this case, a voltage level V is applied between the charging zones_chargeMeans that the charging current I starts to flow in a state where the first LED group 410 and the loopback compensation part 300 are connected in series with each other_cThe threshold voltage level of (c). The block diagram of the above state is shown in fig. 12 b. As shown in fig. 12b, in the charging interval, the second constant current switch SW₂Is in an off state, so that the first LED drives a current I_LED1Can pass through the first current path P₁But flows through the first LED set 410 and the loopback compensating part 300. Therefore, during the charging interval described above,only the first LED set 410 is illuminated and the second LED set is extinguished. The LED drive control unit 500 continuously detects the first LED drive current I flowing through the first current path P1 in the charging interval_LED1So as to control the constant current of the LED to be the preset first LED driving current I_LED1。

In addition, since only the first LED group 410 is emitting light during the first operation interval, the number of LEDs emitting light during the first operation interval is reduced compared to the number of LEDs emitting light during the second operation interval. Therefore, in order to be able to keep the light output of the LED light emitting section 400 almost constant during the first and second operation sections, the second LED driving current I_LED2Can be set lower than the first LED drive current I_LED1The value of (c). More preferably, the first LED may be driven with a current I_LED1And a second LED drive current I_LED2The relationship between them is set as: the light output per operation interval can be made almost the same by making an inverse proportional relationship with the number of LEDs emitting light per operation interval. Therefore, as can be confirmed from fig. 13 (e), the light output of the LED lighting device 1000 can be kept constant throughout the entire interval.

As shown in fig. 13, at the rectified voltage V_recGradually decreases to be less than the charging interval entering voltage level V after reaching the maximum voltage level with the passage of time_chargeWhen (t)₃) The LED driving control unit 500 determines that it is out of the charging interval (i.e., the first operation interval), and may control the 1 st constant current switch SW again in the state illustrated in fig. 12a₁And a second constant current switch SW₂And thus back to the second operation interval. That is, the LED driving control part 500 turns off the first constant current switch SW₁And closing the second constant current switch SW₂。

As shown in fig. 13, at the rectified voltage V_recContinuously decreases to less than the second forward voltage level V with the passage of time_f2When (t)₄) The LED driving control part 500 controls the first constant current switch SW in the state as shown in fig. 12c₁And a second constant current switch SW₂And thus enters the compensation interval. By comparing FIG. 12a and FIG. 12cIt is noted that the control state of the constant current switch of fig. 12a is the same as the control state of the constant current switch of fig. 12 c. Therefore, basically, the control of the constant current switch may not occur, but only the second driving voltage is naturally supplied to the second LED group 420 through the discharge path by the loopback compensation part 300 due to the potential difference. Accordingly, during the compensation interval, the second driving voltage is provided from the loopback compensation part 300 to the first LED group 410 and the second LED group 420, and accordingly, the third LED driving current I flows through the second current path_LED3And the lighting states of the first LED group 410 and the second LED group 420 are maintained. At this time, the third LED drives the current I_LED3Substantially equal to the second LED drive current I_LED2The same is true.

As discussed above, with the LED lighting device 1000 according to embodiment 5 of the present invention, the rectified voltage V after the initial start-up_recIn the period (A), control is sequentially performed for a period of "2-step operation interval (discharge interval) → 2-step operation interval (non-compensation interval) → 1-step operation interval (charge interval) → 2-step operation interval (non-compensation interval) → 2-step operation interval (discharge interval)", and the rectified voltage V is applied_recPeriodically, the above-described control is repeatedly executed.

In the case of using the LED illumination device 1000 according to embodiment 5 of the present invention as described above, the following effects can be brought about as compared with the above-described embodiments 1 to 4: (i) all the LED groups can emit light during the compensation interval, thereby improving light uniformity, (ii) electrical characteristics (power factor, total harmonic distortion, etc.) are improved, and (iii) the number of constant current switches is reduced, thereby facilitating circuit design and reducing manufacturing cost.

Configuration and function of the sixth embodiment of the LED illumination device 1000

Fig. 14 is a schematic block diagram of an LED lighting device (hereinafter, referred to as an "LED lighting device") having improved flicker performance according to a sixth embodiment of the present invention. The structure and function of the LED lighting device according to the present invention will be briefly discussed below with reference to fig. 14.

According to the figureThe LED lighting device 1000 according to the sixth embodiment of the present invention shown in fig. 14 differs from the LED lighting device in the 1 st embodiment shown in fig. 4 in that: it is not the other end of the loop back compensation part 300 that passes through a separate constant current switch (e.g., the third constant current switch SW in fig. 3)₃) And is connected to the LED driving control section, but is connected to the LED driving control section 500 through an nth constant current switch (e.g., a second constant current switch SW2 shown in fig. 14) in common with the negative terminal of an nth LED group (e.g., a2 nd LED group 420 shown in fig. 14), except for being basically similar to the configuration of the LED lighting device 1000 according to embodiment 1 shown in fig. 4. Therefore, the repeated configuration and functions can be referred to the description of fig. 4, and the following discusses the LED lighting device 1000 according to embodiment 6 of the present invention mainly based on the differences from embodiment 1.

As shown in fig. 14, the LED lighting device according to the present invention may include a rectifying part 200, a loopback compensating part 300, an LED light emitting part 400, and an LED driving control part 500. In addition, among the above-described components, the loop back compensation unit 300 and the LED driving control unit 500 may constitute an LED driving circuit.

First, similarly to the first embodiment, fig. 14 discloses the LED light emitting unit including the first LED group 410 and the second LED group 420, but it is clearly understood by those skilled in the art that the number of LED groups included in the LED light emitting unit 400 may be variously changed as needed. However, the following description will be made for the purpose of convenience of description and understanding, with reference to an embodiment in which the LED light emitting unit 400 is configured by two LED groups, but the present invention is not limited thereto. In addition, for the preferred embodiment of the present invention, the design of the first LED group 410 needs to satisfy: has a forward voltage level that can be driven by the second driving voltage supplied by the loopback compensation part 300 in the compensation interval. For an exemplary embodiment, the first LED group 410 may be configured such that: peak value V of rectified voltage_{rec_peak}More than twice the forward voltage level of the first LED group 410. Designed as described above, the first LED group 410 is at an ac voltage V_ACIs always kept in a closed state in the whole period.

In addition, the loopback compensation part 300 according to the present invention is configured in the following manner: using rectified voltage V during charging interval_recAnd charges energy and provides a second driving voltage to the LED light emitting part 400 in the compensation interval. In the example shown in fig. 14, the loopback compensation part according to the present invention is connected in parallel to the second LED group 420 for charging in the second operation interval. More specifically, as shown in fig. 14, one end of the loopback compensation part 300 is connected to a node between the first LED group 410 and the second LED group 420 (i.e., the negative terminal of the first LED group) through a charging path, and is additionally connected to the positive terminal of the first LED group 410 through a discharging path. The other end of the loop-back compensation part 300 and the negative end of the second LED group 420 are commonly connected to the second constant current switch SW₂. Of course, according to the configuration of the embodiment, one end of the loopback compensating part 300 may also be connected to the positive terminal of other LED group. For example, in the embodiment in which the LED light emitting unit 400 is configured by 4LED groups, one end of the loopback compensation unit 300 may be connected to the positive terminal of the second LED group. In this case, the loopback compensation part 300 may supply the second driving voltage to the second LED group (or the second to third LED groups, etc.) within the compensation interval. Hereinafter, an embodiment in which one end of the loop-back compensation unit 300 is connected to the positive terminal of the first LED group 410 and the second driving voltage can be supplied to the first LED group 410 in the compensation interval will be described as a reference.

In addition, the loop-back compensation part 300 is connected to the negative terminal of the first LED group 410 through the charging path at one terminal thereof, and thus is in the second operation interval (i.e., the rectified voltage V)_recIs a second forward voltage level V_f2The above interval) and one end thereof is connected to the positive electrode terminal of the first LED group 410 through the discharge path, and thus, it is configured as follows: in the non-light-emitting interval (i.e. rectified voltage V)_recIs less than the first forward voltage level) to supply the second driving voltage to the first LED group 410. That is, with the sixth embodiment according to the present invention, the loopback compensation part 300 is charged during an operation interval in which the loopback compensation part 300 forms the LED group(s) connected in parallel, and the second LED group may be charged between the compensation intervalsThe driving voltage is supplied to the LED group(s) that become the compensation target. Accordingly, it is preferably constituted in the following manner: the forward voltage level of the LED group(s) connected in parallel by the loopback compensation section 300 is equal to or higher than the forward voltage level of the LED group(s) receiving the second driving voltage.

In addition, the loop-back compensation part 300 is connected to the negative terminal of the first LED group 410 through the charging path at one terminal thereof, and thus is in the second operation interval (i.e., the rectified voltage V)_recIs a second forward voltage level V_f2The above interval) and one end thereof is connected to the positive electrode terminal of the first LED group 410 through the discharge path, and thus, it is configured as follows: in the non-light-emitting interval (i.e. rectified voltage V)_recIs less than the first forward voltage level) to supply the second driving voltage to the first LED group 410. That is, with the sixth embodiment according to the present invention, the loopback compensation part 300 charges during an operation interval in which the loopback compensation part 300 forms the LED group(s) connected in parallel, and the second driving voltage may be supplied to the LED group(s) that become the compensation target during the compensation interval. Therefore, it is preferably constituted in the following manner: the forward voltage level of the LED group(s) connected in parallel by the loopback compensation section 300 is equal to or higher than the forward voltage level of the LED group(s) receiving the second driving voltage. That is, with the 6 th embodiment as shown in fig. 14, the forward voltage level of the first LED group 410 preferably satisfies the constitution that is the same as or less than the forward voltage level of the second LED group 420. However, the present invention is not limited to the above-described embodiment, and in the case that the LED lighting device 1000 according to the present invention includes 4LED groups of the first to fourth LED groups 410 to (not shown), the loopback compensating part 300 may be connected in parallel to the fourth LED group in the fourth operating interval (i.e., the rectified voltage V)_recIs a fourth forward voltage level V_f4The above interval) is charged. In addition, similarly, in the case where the LED illumination device 1000 according to the present invention includes n LED groups of the first to nth LED groups 410 to (not shown), it should be noted that the loop-back compensation part 300 may also be connected in parallel to the nth LED group in the nth operation section(i.e., rectified voltage V)_recIs the nth forward voltage level V_fnThe above interval) is charged.

In addition, the forward voltage level compensated by the loopback compensation part 300 according to the present invention may be designed in various forms according to the capacity of an energy charging and discharging unit (e.g., the first capacitor C1 of fig. 14, etc.) constituting the loopback compensation part 300. For one embodiment, the loop-back compensation part 300 according to the present invention may be configured to satisfy: a voltage level of one-half of the total forward voltage level (a voltage level obtained by adding all the forward voltage levels of the LED groups) can be compensated. Therefore, for the embodiment in which the forward voltage level of the first LED group 410 is designed to be the following to the forward voltage level of the second LED group 420, the configuration of the loopback compensation part 300 according to the present invention may satisfy: can supply a first forward voltage level V_f1The voltage of (c). In this case, as described above, the first LED group 410 may be always maintained in the closed state regardless of the period of the ac power.

In addition, the first constant current switch SW according to the present invention₁And a second constant current switch SW₂The following functions may be performed: is closed to connect the current path or is opened to separate the current path according to the control of the LED driving control part 500, and detects the LED driving current I flowing through the current path_LED-Thereby driving the LED with a current I_LEDThe constant current control is a value set in advance.

The LED drive control section 500 of the present invention shown in fig. 14 is configured as follows: detecting the LED drive current, based on the detected LED drive current I_LEDTo control the first constant current switch SW as described above₁And a second constant current switch SW₂Thereby controlling sequential driving of the first LED group 410 and the second LED group 420. The detailed functions of the LED driving control unit 500 will be specifically discussed below with reference to fig. 15 to 16.

Fig. 15a to 15c are block diagrams showing the switching control state and the LED driving current for each operation section of the LED lighting device according to embodiment 6 of the present invention shown in fig. 14. Hereinafter, an operation process of the LED lighting device according to the sixth embodiment of the present invention as shown in fig. 14 will be discussed in detail with reference to fig. 15a to 15 c.

First, fig. 15a shows the first constant current switch SW during the first operation interval₁And a second constant current power supply SW₂Control state of and LED driving current I_LEDThe relationship between them. As shown in fig. 15a, during the first operation interval, the first constant current switch SW₁And a second constant current switch SW₂In the closed state. In the LED lighting device 1000 according to the present invention, the driving voltage supplied from the LED light emitting unit 400 (the first driving voltage (the rectified voltage V) supplied from the rectifying unit 200 in the non-compensation section) is used_rec) The second driving voltage supplied from the loopback compensation part 300 during the compensation interval) to the voltage level of the first LED group 410, i.e., the first forward voltage level V_f1The above time point may flow the LED driving current I at the first LED group 410_LEDAccordingly, the first LED group 410 is turned on. At this time, the LED driving current I flowing through the first LED group 410_LEDMay be a predetermined first LED driving current I_LED1Can be controlled by a first constant current switch SW₁To constant current control.

Next, fig. 15b shows the first constant current switch SW during the second operation interval₁And the relationship between the control state of the second constant current switch and the LED driving current. Under the control state shown in fig. 15a, the driving voltage supplied to the LED light emitting unit 400 continuously rises to a voltage level equal to or higher than the sum of the forward voltage level of the first LED group 410 and the forward voltage level of the second LED group 420, that is, to the second forward voltage level V_f2At the above time point, the LED driving current I also flows in the second LED group 420_LEDAccordingly, the second LED group 420 is also turned on. At the above-mentioned point of time, for passing through the second current path P₂And a second constant current switch SW connecting the second LED group 420 to the LED driving control part 500₂In a closed state, whereby the passage of the second constant current switch SW can be detected₂While the flowing LED drives the current I_LED. The LED driving control part 500 detects the passing of the second constant current switch SW₂While the flowing LED drives the current I_LEDAnd judging the LED driving current I flowing through the second constant current switch_LEDWhether or not an excessive state (a state where the current rises and/or falls) is experienced while normally maintaining the constant current state. Through the second constant current switch SW₂While the flowing LED drives the current I_LEDIn the case of maintaining a normal constant current state, i.e., stably maintaining the predetermined second LED driving current I_LED2In this case, the LED driving control part 500 may determine that the driving voltage supplied to the LED light emitting part 400 may sufficiently drive the first LED group 410 and the second LED group 420, thereby closing the first constant current switch SW₁And entering a second operation interval. First constant current switch SW at a point of time of entering a second operation section₁And a second constant current switch SW₂Control state of and LED driving current I_LEDFIG. 15b is a graph of the relationship of (A) to (B).

In the state of fig. 15b, that is, in the second operation interval, both the first LED group 410 and the second LED group 420 emit light, but the LED driving current flowing through the first LED group 410 and the LED driving current flowing through the second LED group 420 are different from each other. First, during the second operation interval, the input current I supplied from the rectifying part 200 to the LED light emitting part 400_inFlows through the first LED set 410. However, as shown in FIG. 15b, the current I is input_inAfter passing through the first LED group 410, is divided into a charging current I_cAnd a second LED drive current I_LED2. Charging current I_cThe loop-back compensation part 300 can be charged by supplying the second LED driving current I to the loop-back compensation part 300_LED2To the second LED set 420, thereby causing the second LED set 420 to emit light. I.e. a second LED drive current I supplied to the second LED group_LED2May be the input current I_inMinus the charging current I_cAnd the resulting current. As a result, with the LED lighting device 1000 according to the present invention, during the second operation interval, the loopback compensation part 300 charges while both the first LED group 410 and the second LED group 420 emit light. In addition, during a second operating interval, firstThe light output of the two LED groups 420 becomes lower than that of the first LED group 410, so that an effect of improving the deviation of the light output may be brought about.

In addition, during the second operation interval, the second constant current switch SW₂The controlled current may be constant-current controlled to "second LED drive current I_LED2+ charging current I_c", i.e. the input current I_inIs controlled by the constant current to a value set in advance by the second constant current switch.

In addition, during the second operation interval described above, the second LED group 420 emits light together with the first LED group 410, and thus, the number of LEDs emitting light during the second operation interval is increased compared to the first operation interval. Therefore, in order to be able to keep the light output of the LED light emitting unit 400 almost constant between the first operation interval and the second operation interval, the second LED driving current I_LED2Can be set lower than the first LED drive current I_LED1The value of (c). More preferably, the second LED drive current I_LED2And a first LED drive current I_LED1The relationship therebetween may be set to satisfy: the number of LEDs emitting light in the operation interval is inversely proportional to the number of LEDs emitting light in the operation interval, so that the light output in the operation interval is almost the same.

In addition, at the rectified voltage V_recAfter reaching the maximum voltage level, gradually decreases so as to pass through the second current path P₂While the second LED drive current I flows_LED2When the current level drops below the predetermined value, the LED driving control unit 500 controls the first constant current switch SW in the state shown in fig. 15a₁And a second constant current switch SW₂And thus back to the first operating interval. That is, the LED driving control part 500 closes the first constant current switch SW₁. Therefore, as described above, only the first LED set 410 emits light during the first operation interval, and the LED driving current I is applied at the same time_LEDCan be controlled by constant current to obtain second LED drive current I_LED2The value is obtained.

At rectified voltage V_recContinuously reducing to less than the first forward voltage level V_f1At this time, the LED driving control unit 500 operates the first constant current switch SW in the state shown in fig. 15c₁And the second constantFlow switch SW₂Control is performed to enter the compensation interval. As can be seen by comparing fig. 15a and 15c, the control state of the constant current switch of fig. 15a is the same as that of fig. 15 c. Therefore, basically, the control of the constant current switch may not occur, and the second driving voltage is supplied from the loop-back compensation section 300 to the first LED light emitting section 400 only due to the potential difference. Accordingly, during the compensation interval, the second driving voltage may be provided from the loopback compensation part 300 to the first LED group 410, and accordingly, the third LED driving current I may flow through the first current path_LED3And the lighting state of the first LED group 410 is maintained. At this time, the third LED drives the current I_LED3Substantially equal to the first LED driving current I_LED1The same is true.

As described above, at the rectified voltage V_recSequentially performing control of the first operation interval, the second operation interval, the charging interval, the first operation interval, and the compensation interval in one period, and controlling the rectified voltage V_recThe above-described control process is repeatedly performed periodically in each period.

Fig. 16 is a waveform diagram showing a relationship among a time-dependent rectified voltage, an LED driving current, an input current, and a light output of an LED light emitting unit in the LED lighting device according to embodiment 6 of the present invention shown in fig. 14. Fig. 16 (a) shows the rectified voltage V varying with time_recFIG. 16 (b) shows the LED drive current I varying with time_LEDFig. 16 (c) shows the charging current I of the loop-back compensation unit 300 varying with time_cAnd a discharge current (i.e., a third LED drive current I)_LED3) And (d) of fig. 16 shows a time-varying waveform of the slave ac power supply V_acInput current I to LED lighting device_inAnd (e) of fig. 16 shows a waveform of light output of the LED light emitting unit 400 varying with time.

Referring to fig. 16, if the LED lighting device 1000 is first started, the loop-back compensation unit 300 is not charged, and therefore the LED light emitting unit 400 does not emit light. The first LED group 410 is at the rectified voltage V with the passage of time_recTo a first forward voltage level V_f1Time point (t) of₁) The upper part is lighted. The state diagram at this time is shown in fig. 15 a.

At rectified voltage V_recContinues to rise to reach a second forward voltage level V_f2When (t)₂) The LED driving control part 500 turns off the first constant current switch SW₁Thereby entering a second operation interval. The above state diagram is shown in fig. 15 b. In the second operation interval, the first LED group 410 and the second LED group 420 are both turned on, and at the same time, the charging current is supplied to the loopback compensation section 300 as described above, thereby charging the loopback compensation section 300. In addition, as described above, the second LED driving current I during the second operation interval_LED2Is preferably set lower than the first LED driving current I_LED1Is controlled by a constant current. The above-described relationship can be confirmed by fig. 16 (b) to 16 (d). More specifically, in fig. 16 (b), the second operation section (i.e., the time point t)₂To a time point t₃Interval in between) of the first LED driving current I_LED2Is set to be lower than the first operation section (i.e., the time point t)₁To a time point t₂Interval in between) of the first LED drive current I_LED1Is controlled by a constant current. In addition, during the second operation interval, the charging current Ic is supplied to the loopback compensation section 300, thereby charging the loopback compensation section 300. Accordingly, as shown in fig. 16 (e), the light output of the LED light emitting unit 400 during the second operation interval may be almost the same as the light output of the LED light emitting unit 400 during the first operation interval.

At rectified voltage V_recThrough the highest point and the voltage level is reduced to be less than a second forward voltage level V_f2When (t)₃) The LED driving control part 500 closes the first constant current switch SW as shown in fig. 15a₁Thereby entering the first operation interval. At this time, the LED driving control part 500 may detect the second LED driving current I_LED2To determine the rectified voltage V_recWhether the voltage level of (b) falls below a second forward voltage level V_f2The value of (c). Namely, the constitution can satisfy: at the detected second LED drive current I_LED2When it falls below a predetermined valueThe LED driving control unit 500 may determine that the voltage level of the rectified voltage is lower than the second forward voltage level V_f2。

At rectified voltage V_recContinues to drop below the first forward voltage level V_f1When (t)₄) As shown in fig. 15c, the second driving voltage is supplied from the loopback compensation part 300 to the first LED group 410, so that the first LED group 410 will emit light. As described above, instead of separately performing the control of the constant current switch at the above-described point of time, the discharge from the loopback compensating section 300 to the first LED group 410 may be naturally performed according to the potential difference.

Rectified voltage V_recIs again raised to the first forward voltage level V_f1Above (t)₆) The first LED group 410 is again according to the rectified voltage V as shown in fig. 15a_recAnd emits light. At rectified voltage V_recPeriodically, the sequential control process as described above is repeatedly performed in each cycle.

In addition, as can be confirmed from fig. 16 (e), the LED light emitting unit 400 passes through the rectified voltage V_recMaintains an almost constant light output throughout the interval. This is because, during the second operation interval, the loopback compensation unit 300 is charged while the first LED group 410 and the second LED group 420 are caused to emit light, and therefore, the entire input current I is supplied_inAre not transmitted to the LED light emitting part 400. Of course, the current I can also be driven by the second LED_LED2Set lower than the first LED drive current I_LED1The effect is achieved by performing constant current control.

Although the embodiment in which the LED light emitting unit 400 is composed of two LED groups, i.e., the first LED group 410 and the second LED group 420, has been described above for convenience of description and illustration, those skilled in the art will clearly understand that the same method can also be applied to the embodiment in which the LED light emitting unit 400 is composed of 3 or 4 or more LED groups, and that the above-described embodiment is within the scope of the claims of the present invention.

Configuration and function of embodiment 7 of LED lighting device 1000

Fig. 17 is a schematic block diagram of the LED lighting device according to embodiment 7 of the present invention. The structure and function of the LED lighting device 1000 according to embodiment 7 of the present invention will be discussed in detail below with reference to fig. 17.

The LED lighting device 1000 according to embodiment 7 of the present invention as shown in fig. 17 includes a third LED group 430 and a third constant current switch SW in addition to₃Except for the points, it is similar to the configuration of the LED illumination device 1000 according to embodiment 6 shown in fig. 14. Therefore, the repeated configuration and functions can be referred to the description of fig. 14, and the following discusses the LED lighting device 1000 according to embodiment 7 of the present invention mainly based on the differences from embodiment 6.

As shown in fig. 17, an LED lighting device 1000 according to embodiment 7 of the present invention includes a first LED group 410, a second LED group 420, and a third LED group 430. That is, the LED lighting device 1000 according to embodiment 7 of the present invention is an ac LED lighting device in a 3-step driving method.

For the LED illumination device 1000 according to embodiment 7, the loopback compensation section 300 is configured as follows: the charging is performed during the second and third operation intervals, and the second driving voltage is provided to the first LED group 410 during the compensation interval.

As will be described in more detail, when the LED lighting device 1000 is initially started, the loopback compensating part 300 is not charged, and thus all of the first LED group 410 to the third LED group 430 do not emit light.

At rectified voltage V_recRises with time and reaches a first forward voltage level V_f1At this time, the LED driving current I flows through the first LED group 410_LEDAnd thus the first LED group is lit. At this time, the first constant current switch SW₁Drive the LED with a current I_LED1Constant current control is the first LED drive current I_LED1The value is obtained.

Continues to rise at the voltage level of the rectified voltage Vrec to reach a second forward voltage level V_f2Then, the first LED group 410 and the second LED group can be usedTwo LED groups 420 flowing LED driving current I_LEDSo that the first LED group 410 and the second LED group 420 can be lit. At the above time point, the LED driving control part 500 turns off the first constant current switch SW₁Enters a second operation interval and the second constant current switch SW₂Drive the LED with a current I_LEDConstant current control is the second LED drive current I_LED2. In addition, a simultaneous charging current I_cWill be supplied to the loopback compensation section 300 so that the loopback compensation section 300 starts charging.

At rectified voltage V_recContinues to rise to reach a third forward voltage level V_f3Time, LED drive current I_LEDFlows through the first to third LED groups 410 to 430, so that the first to third LED groups 410 to 430 start to be lighted. At the above time point, the LED driving control part 500 turns off the second constant current switch SW₂And enters a third operation interval, and the third constant current switch SW₃Drive the LED with a current I_LEDConstant current control is the third LED drive current I_LED3The value is obtained. Charging current I same as the second operation interval_cIs also supplied to the loopback compensating section 300 during the third operating interval so that the loopback compensating section 300 can continue charging.

At rectified voltage V_recThrough the highest point and drops to less than a third forward voltage level V_f3When the LED driving control part 500 turns on the second constant current switch SW₂Thereby re-entering the second operation interval. When the rectified voltage passes through the highest point and drops to less than the third forward voltage level V_f3At the time point of (3), through the third constant current switch SW₃While the flowing third LED drives the current I_LED3Accordingly, the LED driving control part 500 can satisfy the following configuration: at a third LED drive current I_LED3In the case where the value falls below the preset value, it can enter the second operation interval. Similarly, the loopback compensator 300 may continue charging during the second operation interval described above.

At rectified voltage V_recContinues to drop below the second forward voltage level V_f2When the LED driving control part 500 closes the firstConstant current switch SW₁Thereby re-entering the first operation interval. At this point in time, the charging process of the loopback compensation section 300 may be ended.

At rectified voltage V_recContinues to drop below the first forward voltage level V_f1At this time, the second driving voltage is naturally supplied from the loopback compensating part 300 to the first LED group 410 according to the potential difference, so that the first LED group 410 emits light in the compensation interval.

Structure and function of embodiment 8 of LED lighting device 1000

Fig. 18 is a schematic block diagram of the LED lighting device according to embodiment 8 of the present invention. The structure and function of the LED lighting device 1000 according to embodiment 8 of the present invention will be discussed in detail with reference to fig. 18.

The LED illumination device 1000 according to the 8 th embodiment of the present invention shown in fig. 18 has a configuration similar to that of the LED illumination device 1000 according to the 6 th embodiment shown in fig. 14, except for the point that the second compensation part 310 is provided in parallel with the second LED group 420. Therefore, the repeated configuration and functions can be referred to the description of fig. 14, and the following discusses the LED lighting device 1000 according to embodiment 8 of the present invention mainly based on the differences from the sixth embodiment.

As shown in fig. 18, the second compensation part 310 according to the present invention may be formed of a second capacitor C₂However, the present invention is not limited thereto, and various electrical charging and discharging units and/or electrical charging and discharging circuits may be used. The second compensation part 310 performs charging during the second operation interval as described above, and can perform a function of supplying the second driving voltage to the second LED group 420 in an operation interval other than the second operation interval (i.e., an operation interval in which the second LED group 420 is turned off). Accordingly, for the 8 th embodiment as shown in fig. 19, the penetration rectified voltage V_recThe first LED group 410 and the second LED group 420 may be kept in the lighting state all the time.

Structure and function of embodiment 9 of LED lighting device 1000

Fig. 19 is a schematic block diagram of the LED lighting device according to embodiment 9 of the present invention. The structure and function of the LED lighting device 1000 according to embodiment 9 of the present invention will be discussed in detail with reference to fig. 19.

The LED illumination device according to embodiment 9 of the present invention as shown in fig. 19 may further include: a first LED driving current setting section 610 for setting a first LED driving current to a desired value; a second LED driving current setting unit 620 for setting the second LED driving current to a desired value; and a third LED driving current setting unit 630 for setting the third LED driving current to a desired value. Except for these points, it is similar in construction to the LED illumination device according to embodiment 6 illustrated in fig. 14. Therefore, the repeated configuration and functions can be referred to the description of fig. 14, and the following discusses the LED lighting device 1000 according to embodiment 9 of the present invention mainly based on the differences from embodiment 6.

In the lighting device 1000 according to the related art described with reference to fig. 2 and 3, there is a case where the first LED driving current I cannot be set individually_LED1A second LED drive current I_LED2A third LED drive current I_LED3Fourth LED drive current I_LED4The problem of (2). That is, the LED lighting device 1000 according to the related art is configured as follows: controlling LED drive current I according to each operation interval in a step wave form_LEDThus, in general, it is possible to set an LED drive current (e.g., a fourth LED drive current I)_LED4) And controlling other LED driving intervals according to the set ratio of the LED driving current. For example, drive a third LED with a current I_LED3Set as the fourth LED drive current I_LED480-90%, drive the second LED with a current I_LED2Set as the fourth LED drive current I_LED465-80% of the first LED and driving the first LED with a current I_LED1Set as the fourth LED drive current I_LED430 to 65% of the above. However, such an LED lighting device 100 according to the related art has a problem that the LED drive current I cannot be set only individually_LEDA problem of (1), whichThe difficulty is particularly that, in order to improve the flicker performance, the LED driving current is not adjusted as described above, but is arbitrarily set for each operation interval. Therefore, the LED lighting device 1000 according to embodiment 9 of the present invention is provided with the first LED driving current setting unit 610 and the second LED driving current setting unit 620 separately, so that the respective LED driving currents can be set as required. Fig. 19 illustrates an embodiment in which the first LED driving current setting part 610 and the second LED driving current setting part 620 described above are respectively implemented by using variable resistors, but those skilled in the art can clearly understand that the driving current setting part may be implemented by other suitable units (e.g., capacitors, etc.) or other suitable circuits.

Configuration and function of embodiment 10 of LED lighting device 1000

Fig. 20 is a schematic block diagram of the LED lighting device according to embodiment 10 of the present invention. The structure and function of the LED lighting device 1000 according to embodiment 10 of the present invention will be discussed in detail below with reference to fig. 20.

The 10 th embodiment illustrated in fig. 20 is similar to the 7 th embodiment described above with reference to fig. 17. Specifically, the 10 th embodiment of fig. 20 is different from the 7 th embodiment of fig. 17 only in the point that a dummy load (dummy load)710 is included instead of the third LED group 430.

For the embodiment shown in FIG. 17, the dummy load 710 is embodied as a first resistor R₁. By including dummy load 710 it is possible to: at rectified voltage V_recIs a second forward voltage level V_f2In the above-described interval, the loop-back compensation unit 300 increases the amount of charge charged by the current flowing through the dummy load 710 by as much as the voltage applied to the dummy load 710. Accordingly, there is an advantage in that the forward voltage level of the first LED group 410 (i.e., the first forward voltage level) can be set to a large value as the amount of charge charged to the loopback compensation part 300 increases. In other words, the increase in unity by including dummy load 710 can be made assuming other conditions are the sameCurrent voltage V_recThe number of LEDs included in the first LED group 410 in a light emitting state is maintained throughout, whereby the flickering performance can be improved.

Structure and function of embodiment 11 of LED lighting device 1000

Fig. 21 is a schematic block diagram of the LED lighting device according to embodiment 11 of the present invention. The LED lighting device and the function according to embodiment 11 of the present invention will be discussed in detail below with reference to fig. 21.

The 11 th embodiment shown in fig. 21 differs from the 7 th embodiment shown in fig. 17 in the following points: the second compensation part 720 is connected in series to the second LED group 420 instead of the third LED group 430, and a discharge path P is additionally formed between the second compensation part 720 and the second LED group 420₅. The second compensation portion 720 shown in fig. 21 is configured as follows: at rectified voltage V_recIs charged in a section of the rectified voltage level being higher than or equal to the second forward voltage level, and is passed through a discharge path P in a section of the rectified voltage level being lower than the second forward voltage level₅And discharges and supplies a second driving voltage to the second LED group 420. Accordingly, in the case of using the 11 th embodiment as shown in fig. 21, at the rectified voltage V_recThe first LED set 410 and the second LED set 420 may be continuously maintained in the lighting state throughout. In addition, since the second compensation part 720 is connected in series to the second LED group 420, an effect of increasing the amount of charge of the loopback compensation part 300 connected in parallel thereto can be obtained.

Structure and function of embodiment 12 of LED lighting device 1000

Fig. 22 is a schematic block diagram of the LED lighting device according to embodiment 12 of the present invention. The structure and function of the LED lighting device 1000 according to embodiment 12 of the present invention will be discussed in detail below with reference to fig. 22.

The 12 th embodiment shown in fig. 22 is different from the 7 th embodiment of fig. 17 in the following points: the node between the second LED group 420 and the third LED group 430 does not pass through the second constant current switch SW₂And is connected to the LED driverThe motion control unit 500 is connected to the negative terminal of the rectifying unit 200. That is, in the 12 th embodiment of fig. 22, the second constant current switch SW₂Are omitted. The above-described 12 th embodiment is an embodiment for achieving the following effects: by reducing the forward voltage level of the first LED group 410 (i.e., the first forward voltage level V)_f1) And supply of the second driving voltage by means of the loopback compensation section 300 becomes easy; increasing the current efficiency by the second LED group 420 and the third LED group 430; the first LED group 410 and the third LED group 430 are enabled to be driven by means of the second driving voltage supplied from the compensation part 300 within the compensation interval. For the 12 th embodiment, it should be noted that the forward voltage level of the first LED group 410 is lower than that of the second LED group 420.

As shown in fig. 22, during the compensation interval (i.e., the rectified voltage V)_recIs less than the first forward voltage level) forms the discharge path P₆And thus the third LED set 430 and the first LED set 410 are lit.

Structure and function of embodiment 13 of LED lighting device 1000

Fig. 23 is a schematic block diagram of an LED lighting device (hereinafter, referred to as "LED lighting device") having improved flickering performance according to embodiment 13 of the present invention. The structure and function of the LED lighting device 1000 according to embodiment 13 of the present invention will be briefly discussed below with reference to fig. 23.

The LED lighting device according to embodiment 13 of the present invention shown in fig. 13 is different from embodiment 6 described above with reference to fig. 14 in the following points: the loopback compensation part 300 secondarily supplies the second driving voltage to the LED light emitting part 400. However, since other configurations are similar to those of embodiment 6, the same configurations and functions will be described using the above description, and the specific configurations and functions of embodiment 13 will be described with emphasis on the description.

Referring to fig. 23, the LED illumination device 1000 according to embodiment 13 of the present invention may include: a rectifying unit 200, a loop-back compensating unit 300, an LED light emitting unit 400, and an LED drive control unit 500. In addition, among the above-described components, the loop back compensation unit 300 and the LED driving control unit 500 may constitute an LED driving circuit.

First, similarly to embodiment 6, the LED light emitting section 400 according to embodiment 13 may be configured by a plurality of LED groups, and the plurality of LED groups included in the LED light emitting section 400 may sequentially emit light according to the control of the LED driving control section 500 and may be sequentially turned off. Fig. 23 discloses the LED light emitting unit 400 including the first LED group 410 and the second LED group 420, but those skilled in the art will appreciate that the number of LED groups included in the LED light emitting unit 400 may be variously changed as needed. Hereinafter, for convenience of explanation and understanding, the 13 th embodiment of the present invention will be described by taking the LED light emitting unit 400 including the first LED group 410 and the second LED group 420 as an example.

In addition, one of the most important features of the loopback compensation part 300 according to the 13 th embodiment is: the loop-back compensation part 300 according to the present invention is configured in such a manner that the second driving voltage can be secondarily supplied to the LED light emitting part. More specifically, the loopback compensation section 300 according to the present invention is configured in the following manner: is connected in parallel with the second LED group 420 at a rectified voltage V_recIs a second forward voltage level V_f2Charging in the above interval and at the rectified voltage V_recIs a first forward voltage level V_f1The second LED group 420 is supplied with the second driving voltage during the above, less than the second forward voltage level Vf2 (hereinafter, referred to as "first compensation interval"), and at the rectified voltage V_recIs a first forward voltage level V_f1The second driving voltage is supplied to the second LED group 420 during the above, less than second forward voltage level interval (hereinafter, referred to as "first compensation interval"), and the rectified voltage V is supplied_recIs less than a first forward voltage level V_f1Can supply the second driving voltage to the first LED group 410 and the second LED group 420 in parallel during the interval (hereinafter, referred to as a "second compensation interval"). In addition, it is more preferable that the first LE during the first compensation interval and the second compensation intervalThe D-group 410 and the second LED group may be configured independently of each other. That is, during the first compensation interval, it is possible to satisfy: first LED group 410 is rectified with respect to voltage V_recAnd independently driven, the second LED group 420 may be independently driven by a second driving voltage; also during the second compensation interval, the first LED group 410 is independently driven by means of the second driving voltage provided by the first discharge circuit, and the second LED group 420 may be relatively independently driven by means of the second driving voltage provided by the second discharge circuit. Hereinafter, a more specific discussion will be made with reference to the drawings.

To perform the functions as described above, as shown in fig. 23, one end of the loopback compensating part 300 according to the present invention may pass through the charging path P₃Connected to a node between the first and

second LED groups

410 and 420 and passing through the first discharge path P₄Connected to the positive terminal of the second LED group 420 and passes through the second discharge path P₅And is connected to the positive terminal of the first LED group 410. In addition, the other end of the loop back compensation part 300 according to the present invention passes through the second constant current switch SW₂And is connected to the LED driving control part 500 without passing through the second constant current switch SW₂Independent current path P₆And is additionally connected to the LED driving control part. Accordingly, for the embodiment of fig. 23, the first LED group 410 is a first group of LEDs and the second LED group 420 is a second group of LEDs. Of course, according to the configurations of the respective embodiments, one end of the loopback compensation part 300 may be connected to the positive terminals of other LED groups, and the second driving voltage may be supplied to the LED group(s) different from the embodiment illustrated in fig. 23 during the first compensation interval and the second compensation interval. The other embodiments described above will be described below with reference to fig. 26.

In addition, for the embodiment illustrated in fig. 23, the loopback compensation section 300 according to the present invention is constructed in the following manner: through a charging path P₃And is connected to a node between the first LED group 10 and the second LED group 420 so as to be capable of operating in the second operation region (i.e., the rectified voltage V)_recIs a second forward voltage level V_f2The above interval) is charged. I.e. in accordance with the inventionIn the 13 th embodiment, the loopback compensation part 300 charges during an operation interval in which the loopback compensation part 300 forms the LED group(s) connected in parallel, and during the first compensation interval, the loopback compensation part 300 supplies the second driving voltage to the LED group(s) connected in parallel, i.e., the LED group of the second group, and may supply the second driving voltage to the LED group of the second group and the LED group of the first group during the second compensation interval. Therefore, it is preferably constituted in the following manner: the loopback compensation unit 300 forms the forward voltage level of the LED group(s) (i.e., the LED group of the second group) connected in parallel to be equal to or higher than the forward voltage level of the LED group(s) (the LED group of the first group) configured to receive the second driving voltage only during the second compensation interval. That is, for the 13 th embodiment as described in fig. 23, the forward voltage level of the first LED group 410 is preferably the same as or less than the forward voltage level of the second LED group 420. However, the present invention is not limited to the above-described embodiment, and in the case where the LED illumination device 1000 according to the present invention includes 4LED groups of the first to 4 th LED groups 410 to (not shown), the loopback compensating part 300 is connected in parallel with the 4 th LED group to operate in the fourth operating interval (i.e., the rectified voltage V)_recIs a fourth forward voltage level V_f4The above section) (in this case, the loopback compensating section 300 passes through the charging path P)₃And to a node between a third LED group (not shown) and a fourth LED group). In addition, it is to be noted that, similarly to this, in the case where the LED illumination device 1000 according to the present invention includes n LED groups of the first to nth LED groups 410 to (not shown), the loopback compensating part 300 is connected in parallel with the nth LED group in the nth operation section (i.e., the rectified voltage V)_recIs the nth forward voltage level V_fnThe above interval) is charged.

That is, it is to be noted that the charging section, the first compensation section, and the second compensation section of the loop-back compensation section 300 according to the present invention may be designed in various forms according to the requirements as described above.

In addition, the forward voltage level compensated by the loopback compensation part 300 according to the present invention may be used to constitute a loopback compensation partEnergy charging and discharging unit of the compensation part 300 (for example, as the first capacitor C of fig. 23)₁Etc.) are designed in various forms.

The LED driving control part 500 according to the present invention as shown in fig. 23 is configured in the following manner: according to the rectified voltage V_recVoltage level of the constant current switch SW connected to the LED light emitting unit 400₁And SW₂The driving of the first LED group 410 and the second LED group 420 is controlled.

As described above, the LED driving control part 500 according to the present invention can determine the rectified voltage V in roughly two ways_recThe voltage level of (c). In one embodiment, the LED driving control part 500 according to the present invention may be configured to satisfy: capable of directly detecting rectified voltage V_recAnd controls the driving of the first LED group 410 and the second LED group 420 based thereon. In another embodiment, the LED driving control part 500 according to the present invention may be configured to satisfy: capable of detecting LED drive current I flowing through LED light emitting unit 400_LEDOr constant current switch(s) SW connected to the LED light emitting section 400₁And SW₂And the first LED group 410 flowing, and drives the current I based on the detected LED_LEDTo control the driving of the first LED group 410 and the second LED group 420. The LED lighting device 1000 according to the present invention is described below with reference to an embodiment configured to directly detect a driving voltage for convenience of description and understanding, but it should be noted that the present invention is also applicable to an LED lighting device configured to be capable of controlling driving between a plurality of LED groups by a driving current detection method.

In addition, the first constant current switch SW according to the present invention₁And a second constant current switch SW₂Is composed in the following way: the current path is connected by closing or separated by opening according to the control of the LED drive control part 500, and the LED drive current I flowing through the connected current path is detected_LEDAnd the current I is driven by a preset value_LEDAnd performing a function of rectification control.

The LED drive control section 500 of the present invention shown in fig. 23 is configured as follows: detecting rectified voltage V_recAnd based on the detected rectified voltage V_recTo the first constant current switch SW₁And a second constant current switch SW₂The driving of the first LED group 410 and the second LED group 420 is controlled. The detailed functions of the LED driving control unit 500 will be specifically discussed below with reference to fig. 24 to 25.

Fig. 24a to 24d are block diagrams illustrating the switching control state for each operation section, the driving current for each LED group, and the charging/discharging current for the loopback compensator of the LED lighting device according to embodiment 13 of the present invention shown in fig. 23. Fig. 25 is a waveform diagram illustrating a time-dependent rectified voltage, a first LED group drive current, a second group LED drive current, and a loopback compensator charge/discharge current of the LED lighting device according to embodiment 13 of the present invention shown in fig. 23.

Hereinafter, the operation of the LED lighting device 1000 according to the 13 th embodiment of the present invention shown in fig. 23 will be discussed in detail with reference to fig. 24a to 24d and fig. 25.

First, as shown in fig. 25, when the LED lighting device 1000 is initially started, the loopback compensator 300 is in an uncharged state. Accordingly, at the rectified voltage V_recReaches a first forward voltage level V_f1Previously, the LED driving current did not flow through the first LED group 410 or the second LED group 420. In this state, the first constant current switch SW₁Is in a closed state, and the second constant current switch SW₂Is in an off state. The rectified voltage V supplied to the LED light-emitting unit 400 with the passage of time_recFrom the forward voltage level of the first LED group 410, i.e., the first forward voltage level V_f1The above time point (time point t in fig. 25)₁) Begin flowing a first current I to the first LED set 410₁And thus the first LED set 410 lights up and enters the first operation section. Fig. 24a illustrates the first operation interval period (time point t of fig. 25) described above₁To a time point t₂) First constant current inSwitch SW₁And a second constant current switch SW₂And LED group drive current I_{LED_G}As shown in FIG. 24a, during the first operation interval, the first current I₁Flows through the first LED set 410, according to which a first current I₁For a first LED drive current I_LED1While driving a current I for the first LED group_{LED_G1}. In addition, during the first operation interval, the first LED driving current I flowing through the first LED group 410_LED1For a preset first LED driving current value, it can be controlled by a first constant current switch SW₁To be controlled by a constant current. In addition, as shown in fig. 24b and 25, during the second operation interval, the first LED group driving current I flowing through the first LED group 410_{LED_G1}Is "2 nd current I₂+ third current I₃"; a second LED group drive current I flowing through the second LED group_{LED_G2}Is a second current I₂(ii) a By a second constant current switch SW₂Controlled second LED drive current I_LED2Is "second current I₂+ third current I₃". Accordingly, during the second operation interval, the second LED drives the current I_LED2(i.e., the second current I₂+ third current I₃) A second constant current SW at a preset second LED driving current value₂To constant current control. It can be confirmed from fig. 25 that, in addition to the initial start-up time of the LED lighting device 1000, since the first LED group 410 and the second LED group 420 continue to be kept in the lighting state (that is, since the number of LEDs emitting light is the same), the predetermined first LED driving current value and the predetermined second LED driving current value for constant current control of the LED driving current can be freely set. As shown in fig. 25, the preset first LED drive current value and the preset second LED drive current value for the constant current control of the LED drive current are set to almost the same current value. On the contrary, a part of the LED groups are at the rectified voltage V_recIn another embodiment of the present invention, the extinguishing unit may be configured to extinguish during a part of a cycle of the vehicle, wherein: the LED drive current value for constant current control of the LED drive current is inversely proportional or substantially equal to the number of LEDs litThe upper is inversely proportional. The other embodiments described above will be described below with reference to fig. 26.

In addition, as time passes, the voltage is rectified at V_recGradually decreases to less than a second forward voltage level V after reaching the maximum voltage level_f2Time point (time point t of fig. 25)₃) On top, the LED driving control part 500 turns off the second constant current switch SW₂So that the second current path P₂Separate and close the first constant current switch SW₁To connect the first current path P₁Thereby entering a first compensation interval. Illustrated in fig. 24: the first compensation interval (rectified voltage V)_recIs a first forward voltage level V_f1Above and below the second forward voltage level V_f2The interval of (1); time point t of fig. 25₃Time point t₄Time t₆Time point t₇Time t₈Time point t₉) First constant current switch SW in the period₁And a second constant current switch SW₂Control state of and LED group drive current I_{LED_G}. As shown in fig. 24c and 25, during the first compensation interval, the rectified voltage V_recIs a first forward voltage level V_f1Above, therefore, the first LED set 410 is driven by the rectified voltage 300, and the second LED set 420 is driven by the first discharge path P₄And a second driving voltage supplied from the loopback compensation part 300.

As shown in fig. 24, during the first compensation interval, the first current I flows through the first LED set 410 during the first operation interval as described above₁. Accordingly, the first LED group drives the current I during the first compensation interval_{LED_G1}Is a first current I₁And a first current I₁By means of a first constant current switch SW₁And is controlled by a constant current to a preset first LED driving current value. In contrast, as shown in fig. 24c, during the first compensation interval described above, the second constant current switch SW₂In the off state, the first discharge circuit connected in the order of the loopback compensation part 300 → the first discharge path P4 → the second LED group 420 → the loopback compensation part 300 is thus constructed, and accordinglyThrough the first discharge circuit, the fourth current I₄Flows through the second LED set 420 so that the second LED set 420 can maintain a lighting state. At this time, in order to reduce or eliminate the light output deviation per operation interval, the fourth current I flowing through the second LED group 420 during the first compensation interval₄May be configured to correspond to the second current I flowing through the second LED group during the second operation interval₂The same is true.

In addition, as time passes, the voltage is rectified at V_recGradually decreases to less than a first forward voltage level V_f1Time point (time point t of fig. 25)₄) In the above, the LED driving control part 500 may enter the second compensation interval. Illustrated in fig. 24 d: less than the second compensation interval (rectified voltage V)_recIs less than a first forward voltage level V_f1The interval of (1); time point t of fig. 25₄Time point t₆Time t₈Time point t₁₀) First constant current switch SW in the period₁And a second constant current switch SW₂Control state of and LED group drive current I_{LED_G}. As shown in fig. 24d, the first constant current switch SW during the second compensation interval₁And a second constant current switch SW₂And the first constant current switch SW during the first compensation interval₁And a second constant current switch SW₂And can be controlled by the voltage level of the loopback compensating part 300 and the rectified voltage V_recThe potential difference between the voltage levels of (a) and (b) inherently forms a first discharge circuit and a second discharge circuit. That is, as shown in fig. 24d, during the second compensation interval described above, the first LED group 410 and the second LED group 420 may be respectively connected in parallel with the loopback compensation part 300 to obtain the supply of the second driving voltage. More specifically, during the second compensation interval, the second LED group 420 is connected to the loopback compensation part through the first discharge circuit as described above, and thus is driven by the fourth current I4. In contrast, the first LED group 410 passes through the loop-back compensation part 300 → the second discharge path P₅→ the first LED group 410 → the first constant current switch SW₁→ the LED drive control part 500 → the second loop back compensation part 300 for connectionThe discharge current is connected to the loopback compensation section 300. During the second compensation interval, the fifth current I is passed through the second discharge circuit₅May flow through the first LED set 410 so that the first LED set 410 may maintain an illuminated state. Accordingly, during the second compensation interval, the first LED group driving current I flowing through the first LED group 410_{LEDG_1}Is a fifth current I₅And, in order to reduce or eliminate the deviation of the light output by the operation section, the fifth current I5 flowing through the first LED group 410 during the second compensation section may be controlled by the first constant current switch SW₁Is controlled to be a first current I flowing through the first LED group in a first compensation interval₁The same value. The results are graphically shown in fig. 25.

As described above, the rectified voltage V at the initial start of the LED lighting device 1000_recDuring a period of time of the first constant current switch SW₁And a second constant current switch SW₂Control state of and LED group drive current I_{LED_G}The description is given. After initial startup, the LED lighting device 1000 is at the rectified voltage V_recDuring a period of time of the first period, according to the rectified voltage V_recThe control of "the second compensation section of fig. 24d → the first compensation section of fig. 24c → the second operation section (charging section) of fig. 24b → the first compensation section of fig. 24c → the second compensation section of fig. 24 d" is sequentially performed while increasing or decreasing, and the rectified voltage V is applied_recThe above-described control process is repeatedly performed periodically in each cycle. In addition, with the above configuration, in the LED lighting device 1000 according to embodiment 13, the first LED group 410 and the second LED group 420 can pass through the rectified voltage V after the initial start of the LED lighting device 1000_recThe lighting state is maintained.

Structure and function of embodiment 14 of LED lighting device 1000

Fig. 26 is a schematic block diagram of the LED lighting device according to embodiment 14 of the present invention. The LED lighting device 1000 according to the 14 th embodiment of the present invention shown in fig. 26 is similar to the LED lighting device according to the 13 th embodiment shown in fig. 23 except for the following pointsThe construction of the lighting device 1000 is similar: also comprises a third LED group 430 and a third constant current switch SW₃And a third current path P₇And one end of the loop back compensation part 300 passes through the third constant current switch SW₃And is connected to the LED driving control part 500. Therefore, the repeated configuration and functions can be referred to the description of fig. 23, and the following discusses the LED lighting device 1000 according to embodiment 14, mainly based on the differences from embodiment 13.

As for the 14 th embodiment illustrated in fig. 26, the loopback compensating section 300 according to the present invention is different from the third embodiment in that: during the 2 nd and third operation intervals, the LED drive control part 500 performs charging according to the rectified voltage V_recControls the sequential driving of the second LED group 420 and the third LED group 430. In addition, the loop-back compensation section 300 according to the present invention may be configured to satisfy: can be at rectified voltage V_recIs a first forward voltage level V_f1Above and below the second forward voltage level V_f2Supplies the second LED group 420 and the third LED group 430 with the second driving voltage during the interval (first compensation interval) and at the rectified voltage V_recIs less than a first forward voltage level V_f1During the interval (second compensation interval), the second driving voltage is supplied to the LED group of the first group (the first LED group 410 in fig. 26) and the LED group of the second group (the second LED group 420 and the third LED group 430 which are connected in series with each other in fig. 26), respectively.

Specifically, the first constant current switch SW is turned on at the initial start of the LED lighting device 1000₁Is in a closed state, and the second constant current switch SW₂And a third constant current switch SW₃Is in an off state. In the above state, the voltage level rises to reach the first forward voltage level V_f1Starts to flow the first LED drive current I at the time point_LED1And thus the first LED group 410 emits light.

At rectified voltage V_recContinues to reach the second forward voltage level V with the passage of time_f2At the time point of (1), LEThe D-drive control part 500 turns off the first constant current switch SW₁And closing the second constant current switch SW₂And a third constant current switch SW₃Thereby entering a second operation interval. During the second operation interval, the first LED set 410 and the second LED set 420 are turned on, and the charging current passes through the charging path P₃And supplied to the loopback compensating section 300. In addition, similarly to embodiment 13, during the above-described second operation interval of embodiment 14, "charging current + second LED driving current I_LED2"flows through the first LED group 410, and the second LED drives the current I_LED2The second LED group 420 flows, and the charging current flows through the loopback compensation part 300. However, unlike the 13 th embodiment, the second constant current switch SW is operated during the second operation section of the 14 th embodiment₂Is composed in the following way: the current I is driven only for the second LED by a preset value_LED2And performing constant current control.

At rectified voltage V_recContinues to rise with time and reaches a third forward voltage level V_f3At the time point (c), the LED driving control part 500 turns off the second constant current switch SW₂And thus enters a third operation interval. During the third operation interval, the first to third LED sets 410 to 430 are turned on, and the charging current flows through the charging path P₃And supplied to the loopback compensating section 300. During the above-described third operating interval of embodiment 14, the "third LED drive current I_LED3"flows through the first LED group 410, and the third LED drives a current I_LED3The charging current flows through the second LED group 420 and the third LED group 430, and the charging current flows through the loopback compensation part 300. Third constant current switch SW₃Will "charging current + third LED drive current I_LED3"constant current control is a preset value.

In addition, as time passes, the voltage is rectified at V_recAfter reaching the peak, the voltage level of the first positive voltage starts to fall and reaches the second positive voltage level V again_f2At the time point of (a), the LED driving control part 500 closes the second constant current switch SW₂Thereby re-entering the second operation interval.

The voltage level of the rectified voltage Vrec continues to drop with the passage of time and reaches the first forward voltage level V again_f1At the time point (c), the LED driving control part 500 turns off the second constant current switch SW₂And a third constant current switch SW₃And closing the first constant current switch SW₁Thereby entering a first compensation interval. During the first compensation interval mentioned above, the rectified voltage V_recIs a first forward voltage level V_f1Above, therefore, the first LED set 410 is rectified by the rectified voltage V_recThe second LED group 420 and the third LED group 430 are controlled by the loop-back compensation unit 300 through the first discharge path P₄And the second driving voltage supplied. That is, during the first compensation interval described above, the second constant current switch SW₂And a third constant current switch SW₃In the off state, the loop back compensation part 300 → the first discharge path P is formed₄→ the second LED group 420 → the third LED group 430 → the loopback compensating part 300. Accordingly, a first discharge current (e.g., the fourth current I of FIG. 24 c) passes through the first discharge circuit₄) The second LED group 420 and the third LED group 430 flow, and thus the second LED group 420 and the third LED group 430 maintain the lighting state.

In addition, at the rectified voltage V_recGradually decreases to less than a first forward voltage level V with the passage of time_f1The LED driving control part 500 may enter the second compensation interval at the time point (e). The first constant current switch SW during the second compensation interval₁To a third constant current switch SW₃And the first constant current switch SW during the first compensation interval₁To a third constant current switch SW₃And may be based on the voltage level of the loopback compensation part 300 and the rectified voltage V_recThe first discharge circuit and the second discharge circuit are naturally formed by the potential difference between the voltage levels of (a) and (b). That is, during the second compensation interval, the LED group of the first group (the first LED group 410) and the LED group of the second group (the second LED group 420 and the third LED group 430 connected in parallel to each other) are connected in parallel to the loopback compensation part 300, respectivelyAnd receives a second driving voltage. More specifically, during the second compensation interval, the second LED group 420 and the third LED group 430 are connected to the loopback compensation part through the first discharge circuit as described above, and are driven by the first discharge current. In contrast, the first LED set 410 is connected as the loop back compensation part 300 → the second discharge path P₅→ the first LED group 410 → the first constant current switch SW₁→ the LED driving control unit 500 → the loopback compensating unit 300, and is connected to the loopback compensating unit 300. During the second compensation interval, a second discharge current (e.g., the fifth current I of FIG. 24 d) is passed through the second discharge circuit₅) Flows through the first LED set 410 so that the first LED set 410 can maintain a lighting state.

After initial startup, the LED lighting device 1000 is at the rectified voltage V_recAccording to the rectified voltage V within one period_recThe control of "second compensation interval → first compensation interval → second operation interval (charging interval) → third operation interval (charging interval) → second operation interval → first compensation interval → second compensation interval" is performed in sequence while increasing or decreasing, and the rectified voltage V is applied_recThe above-described control is repeatedly executed periodically in each cycle. Further, with the above configuration, the rectified voltage V after the initial start of the LED lighting device 1000_recThe first LED group 410 and the second LED group 420 of the LED lighting device 1000 according to the embodiment 13 can be kept in the lighting state, and the third LED group 430 can be driven by the rectified voltage V_recIs selectively turned on/off.

As discussed above, in the LED lighting device 1000 according to embodiment 14, the third LED group 430 is selectively turned on/off according to the operation section, and thus, the number of LEDs emitting light varies according to the operation section. Therefore, in order to eliminate or minimize the light output deviation per operation section, the magnitudes of the LED driving currents flowing through the LED groups per operation section may be controlled to be different from each other. For example, the magnitude of the LED driving current during the operation interval (first compensation interval, second compensation interval, third operation interval) in which all of the first to third LED groups 410 to 430 are turned on may be controlled to be smaller than the magnitude of the LED driving current during the operation interval (second operation interval) in which only the first and

second LED groups

410 and 420 are turned on. At this time, the magnitude of the LED driving current may be determined to be a magnitude that may be in an inverse relationship or an approximately inverse relationship with the number of LEDs emitting light.

In addition, since the third LED group 430 is selectively turned on/off, a configuration may be preferably adopted in which the number of the plurality of LEDs used to configure the third LED group 430 can be made smaller than the number of LEDs of the second LED group 420. In addition, since the third LED group 430 is selectively turned on/off, it may be preferable to adopt a configuration in which the forward voltage level of the third LED group 430 is less than the forward voltage level of the first LED group 410 and/or the forward voltage level of the second LED group 420.

The operation of the LED illumination device 1000 according to the 14 th embodiment of the present invention including the first to third LED groups 410 to 430 is described above. However, it may also be applied to the LED lighting device of other embodiments including the first to nth LED groups 410 to (not shown) according to the same principle. For example, in the other embodiments described above, it is assumed that one end of the loopback compensating unit 300 is connected to the LED driving control unit 500 through an n-th constant current switch (not shown), and the other end of the loopback compensating unit 300 is connected to a node between the first LED group 410 and the second LED group 420 through a charging path, is connected to the positive terminal of the second LED group 420 through a first discharging path P4, and is connected to the positive terminal of the second LED group 420 through a second discharging path P₅But to the positive terminal of the first LED group 410. For the above embodiment, the charging interval of the loopback compensation part 300 is from the second operating interval to the nth operating interval, and during the charging interval, the second LED group 420 to the nth LED group are sequentially driven. In the compensation section, the first LED group and the second LED group are connected in parallel to each other in the loopback compensation unit 300. Therefore, in the first compensation interval (rectified voltage V)_recIs a first forward voltage level V_f1Above and below the second forward voltageLevel V_f2Interval) of the loop-back compensation part 300, the second to nth LED groups are supplied with the second driving voltage, and may be in the second compensation interval (rectified voltage V)_recIs less than a first forward voltage level V_f1) Meanwhile, the loopback compensation part 300 supplies a second driving voltage to the first group of LED groups and the second group of LED groups, respectively.

In addition, assume an embodiment: including first through fourth LED groups 410 through 410 (not shown); one end of the loop-back compensation unit 300 is connected to the LED drive control unit 500 through a fourth constant current switch (not shown); the other end of the loop back compensation part 300 passes through a charging path P₃And is connected to a node between the second LED group 420 and the third LED group 430; is connected to the positive terminal of the third LED group 430 through the first discharge path; is connected to the positive terminal of the first LED group 410 through the second discharge path. In the other embodiment, the first LED group is the first LED group 410 and the second LED group 420 connected in series, and the second LED group is the third LED group 430 and the fourth LED group connected in series. In addition, for the above embodiment, the charging interval is the third operating interval and the fourth operating interval, and the first compensation interval is the rectified voltage V_recIs a first forward voltage level V_f1Above and below the third forward voltage level V_f3And the second compensation interval is the rectified voltage V_recIs less than a first forward voltage level V_f1The interval of (2).

Therefore, during the charging interval, the third LED group 430 and the fourth LED group are based on the rectified voltage V_recAre sequentially driven, and during a first compensation interval, the first LED group 410 and the second LED group 420 are driven according to the rectified voltage V_recAre sequentially driven. In addition, during the first compensation interval, the loopback compensation part 300 supplies the second driving voltage to the third LED group 430 and the fourth LED group (i.e., the LED group of the second group), and during the second compensation interval, the loopback compensation part 300 may supply the LED group of the first group (the first LED group 410 and the second LED group 420 connected in parallel with each other) and the LED group of the second groupThe second driving voltage is supplied to (the third LED group 430 and the fourth LED group forming a series connection with each other), respectively.

As discussed above, note that: the loopback compensation part 300 according to the present invention can be applied to various configurations of LED groups and is not limited to the specific embodiment described in the present invention.

Structure and function of embodiment 15 of LED lighting device 1000

Fig. 27 is a schematic block diagram of the LED lighting device according to embodiment 15 of the present invention. The structure and function of the LED lighting device 1000 according to embodiment 15 of the present invention will be discussed in detail below with reference to fig. 27.

The LED illumination device 1000 according to the 15 th embodiment of the present invention as shown in fig. 27 may further include: a first LED drive current setting unit 610 for setting the first LED drive current I_LED1Setting the value as required; and a second LED drive current setting section 620 for setting the second LED drive current I_LED2Set to the desired value. Except for the above points, it is similar in configuration to the LED illumination device 1000 according to embodiment 13 shown in fig. 23. Therefore, the repetitive structure and functions of the LED lighting device 1000 according to embodiment 15 can be described with reference to fig. 23 to 25.

The LED lighting device 1000 according to the related art described with reference to fig. 2 and 3 has a problem in that the first LED driving current I cannot be set individually_LED1A second LED drive current I_LED2A third LED drive current I_LED3And a fourth LED drive current I_LED4. That is, the LED lighting device according to the related art is configured as follows: since the LED driving current for each operation section is controlled in a step wave form, it is generally configured as follows: can set an LED drive current (e.g., a fourth LED drive current I)_LED4) And the other LED drive currents are controlled according to the set proportion of the LED drive currents. For example, drive a third LED with a current I_LED3Set as the fourth LED drive current I_LED480-90%, drive the second LED with a current I_LED2Set as the fourth LED drive current I_LED465-80% of the first LED and driving the first LED with a current I_LED1Set as the fourth LED drive current I_LED430 to 65% of the above. However, such an LED lighting device 100 according to the related art has a problem that the LED drive current I cannot be set only individually_LEDThe problem of (2) is that, in order to improve the flicker performance, the LED driving current is not adjusted as described above, but is arbitrarily set for each operation interval. Therefore, the LED lighting device 1000 according to embodiment 16 of the present invention is provided with the first LED driving current setting unit 610 and the second LED driving current setting unit 620 independently from each other, so that the respective LED driving currents can be set as required. Fig. 27 illustrates an embodiment in which the first LED driving current setting part 610, the second LED driving current setting part 620, and the third LED driving current setting part 630 are respectively implemented by using variable resistors, but those skilled in the art can clearly understand that the driving current setting part may be implemented by other suitable units (e.g., capacitors, etc.) or other suitable circuits.

Structure and function of embodiment 16 of LED lighting device 1000

Fig. 28 is a schematic block diagram of an LED lighting device according to embodiment 16 of the present invention. The structure and function of the LED lighting device according to embodiment 16 of the present invention will be discussed in detail below with reference to fig. 28.

The LED lighting device 1000 according to the 16 th embodiment of the present invention shown in fig. 28 is similar to the LED lighting device 1000 according to the 14 th embodiment described with reference to fig. 26, except that a dummy load (dummy load)630 is included instead of the third LED group 430.

For the embodiment shown in fig. 17, the dummy load 630 is implemented by a first resistor R1. By including dummy load 630: at rectified voltage V_recIs a second forward voltage level V_f2In the above interval, the current is passed through the dummy load 630Flows so that the amount of charge charged by the loopback compensating part 300 increases by as much as the voltage applied to the dummy load 630. Accordingly, there is an advantage in that the forward voltage level of the first LED group 410 (i.e., the first forward voltage level) can be set to a large value due to an increase in the amount of charge charged to the loop compensation part 300. In other words, the rectified voltage V can be increased by including dummy load 630, assuming other conditions are the same_recThe number of LEDs included in the first LED group 410 in a light emitting state is maintained throughout, whereby the flickering performance can be improved.

Claims

1. An LED lighting device comprising:

a rectifying section configured to rectify an alternating-current AC voltage and output the rectified voltage as a first driving voltage;

a loopback compensation section configured to charge the second driving voltage using the rectified voltage;

an LED light emitting part including a first LED group and a second LED group connected in series, wherein at least one of the first LED group and the second LED group is configured to emit light when receiving a first driving voltage in a non-compensation section in which the LED light emitting part is driven by a rectified voltage and to emit light when receiving a second driving voltage in a compensation section in which the LED light emitting part is driven by the second driving voltage from a loopback compensation part;

an LED driving controller including a first constant current switch and a second constant current switch, and configured to control driving of the first LED group and the second LED group based on a level of the rectified voltage,

the output light of the LED light emitting section is substantially constant between the non-compensated interval and the compensated interval,

wherein one end of the loopback compensation part is connected to the cathode of the first LED group and the anode of the second LED group via a charging path and the one end is connected to the anode of the first LED group via a discharging path,

the other end of the loop-back compensation part is connected to the first constant current switch, the cathode of the second LED group is connected to the second constant current switch,

wherein the non-compensation interval corresponds to a period in which a level of the rectified voltage is higher than a threshold voltage capable of driving the first LED group and the second LED group,

wherein the compensation interval corresponds to a period in which a level of the rectified voltage is lower than a critical voltage capable of driving the first and second LED groups.

2. The LED lighting device of claim 1,

the first LED group is configured to emit light, and the loopback compensation portion is located on a current path of a first LED driving current corresponding to the light emission of the first LED group.

3. The LED lighting device of claim 1, wherein the loopback compensation component comprises a capacitor.

4. The LED lighting device of claim 1, wherein the loopback compensation component is configured to charge the second drive voltage during a charging interval, the charging interval being a predetermined time period in a non-compensation interval.

5. The LED lighting device of claim 4, wherein a level of the rectified voltage during the charging interval is higher than a level of the rectified voltage during a non-compensation interval other than the charging interval.

6. The LED lighting device of claim 4, wherein the first LED group is configured to emit light and a first LED drive current flows through the first LED group during the charging interval, the first LED drive current corresponding to the emission of light by the first LED group.

7. The LED lighting apparatus of claim 6, wherein each of the first and second LED groups is configured to emit light and a second LED driving current flows through each of the first and second LED groups during a non-compensation interval other than the charging interval, the second LED driving current corresponding to the light emission of the first and second LED groups.