CN214228504U - LED lighting circuit and lighting circuit - Google Patents

Abstract

The present application relates to an LED lighting circuit and a lighting circuit. An LED lighting circuit comprising: the light-emitting circuit comprises a light-emitting unit or at least two light-emitting units which are sequentially connected in series; a drive circuit, the drive circuit comprising: the power input end is electrically connected with the first end of the light-emitting circuit; the power supply input end is used for being electrically connected with the output end of the last LED lighting circuit or a power supply; one or at least two first switch units, each first switch unit being connected in parallel with a corresponding one of the light emitting units; and the current limiting circuit is used for limiting the current flowing through the light emitting circuit to be a first preset value, and the first preset value is less than or equal to the rated current of the light emitting unit. The lighting circuit comprises at least two LED lighting circuits which are sequentially connected in series.

Description

LED lighting circuit and lighting circuit

Technical Field

The present application relates to the field of electronic circuit technology, and in particular, to an LED lighting circuit and lighting circuit.

Background

As a new industry that is rapidly developing, the LED (Light Emitting Diode) industry has become an important way of information dissemination, and has been widely applied in the fields of advertising, stage background, traffic guidance, and the like. As the social demand for LED displays increases, LED circuits are also constantly being updated. When the LED emits light, the on-off state of part of the LED needs to be changed, and in some scenes, the whole current of the LED lighting circuit needs to be unchanged.

When the existing circuit is used, if the LED emits light and stops emitting light, the current of the whole circuit is changed, and the stability of the current is low.

SUMMERY OF THE UTILITY MODEL

The present application aims to solve at least one of the above-mentioned technical drawbacks, and proposes the following technical solutions.

In order to solve the above technical problem, in a first aspect, the present application provides an LED lighting circuit, including:

the light-emitting circuit comprises a light-emitting unit or at least two light-emitting units which are sequentially connected in series;

a drive circuit, the drive circuit comprising:

a power input end electrically connected with a first end of the light emitting circuit; the power supply input end is used for being electrically connected with the output end of the last LED lighting circuit or a power supply;

one or at least two first switch units, each of which is connected in parallel with a corresponding one of the light emitting units;

the current limiting circuit is used for limiting the current flowing through the light emitting circuit to be a first preset value, and the first preset value is smaller than or equal to the rated current of the light emitting unit.

Optionally, the current limiting circuit comprises:

the current limiting unit is used for controlling the electrical conduction between the first end and the second end of the current limiting unit according to a first control signal of the first control circuit, when the first end and the second end of the current limiting unit are electrically conducted, the current allowed between the first end and the second end of each current limiting unit is a second preset value, and the sum of the second preset values of the at least one current limiting unit is the first preset value.

Optionally, the current limiting unit is a current limiting switch unit, and a first end of the current limiting unit is a first end of the current limiting switch unit; the second end of the current limiting unit is the second end of the current limiting switch unit, and the third end of the current limiting unit is the control end of the current limiting switch unit.

Optionally, the light emitting circuit comprises three light emitting units connected in series in sequence; the LED lighting circuit comprises three first switch units, each first switch unit is connected with one corresponding light-emitting unit in parallel, and the colors of light emitted by the three light-emitting units are respectively a first color, a second color and a third color.

Optionally, each first switch unit has a first end electrically connected to the first end of the corresponding light-emitting unit, a second end electrically connected to the second end of the corresponding light-emitting unit, and a third end electrically connected to an external second control circuit, and is configured to control an electrical on-off state between the first end and the second end of the first switch unit according to a second control signal of the second control circuit, where the electrical on-off state of any one first switch unit is the same as or different from the electrical on-off states of other first switch units.

Optionally, the first switch unit is a field effect transistor, a triode, or an insulated gate bipolar transistor.

Optionally, the LED lighting circuit further comprises a clamping circuit, a first end of the clamping circuit is electrically connected to the power input end, and a second end of the clamping circuit is electrically connected to the output end.

Optionally, the clamp circuit comprises: the voltage divider unit, the second switch unit, the comparison unit and the first node;

the first end, the second end and the third end of the voltage division unit are respectively and electrically connected with the power input end, the output end and the first node;

the first end and the second end of the second switch unit are respectively and electrically connected with the power supply input end and the output end;

and the comparison unit is used for controlling the electrical conduction between the first end and the second end of the second switch unit when the voltage of the first input end is greater than the voltage of the second input end.

Optionally, the voltage dividing unit includes: a first voltage dividing unit and a second voltage dividing unit;

the first end of the first voltage division unit is electrically connected with the power supply input end;

the second end of the second voltage division unit is electrically connected with the output end;

the second end of the first voltage division unit and the first end of the second voltage division unit are jointly used as the third end of the voltage division unit and are electrically connected with the first node.

In a second aspect, the present application also provides a lighting circuit comprising: at least two LED lighting circuits of the first aspect connected in series in sequence.

According to the technical scheme, each first switch unit is connected with one corresponding light-emitting unit in parallel, each first switch unit can independently control the light-emitting unit corresponding to the first switch unit to be turned on or turned off, the current limiting circuit is used for limiting the current flowing through the light-emitting circuit to be a first preset value, the first preset value is smaller than or equal to the rated current of the light-emitting unit, when the light-emitting units are connected in series, even if only part of the light-emitting units work, the current output by the LED light-emitting circuit is limited to be the first preset value by the current limiting circuit, therefore, the light-emitting units connected in series are supported, under the condition that any number of the light-emitting units emit light, the current is prevented from exceeding the limit, the reliability and the safety can be guaranteed, the light-emitting units are prevented from being burnt, and the service life of the LED lighting circuit is prolonged.

Drawings

Fig. 1 is a schematic structural diagram of an LED lighting circuit according to an embodiment of the present application.

Fig. 2 is a schematic structural diagram of another LED lighting circuit provided in the embodiment of the present application.

Fig. 3 is a schematic structural diagram of an illumination circuit according to an embodiment of the present application.

Reference numerals:

10-an LED lighting circuit;

11-a drive circuit; 111-power input; 112-an output terminal; q1-first switching unit; 113-a current limiting circuit; q2-current limiting unit;

12-a light emitting circuit; l1-light emitting unit;

13-a clamp circuit; 131-a voltage dividing unit; 132-a comparison unit; 133-a first node; q3-second switching unit; r1 — first partial pressure unit; r2-second voltage dividing unit.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

Referring to fig. 1, an embodiment of the present application provides an LED (Light Emitting Diode) lighting circuit, where the LED lighting circuit 10 is used for lighting, and the LED lighting circuit 10 may be specifically applied in the fields of advertising, stage background, traffic guidance, and the like. The LED lighting circuits 10 may be used individually or in series or parallel with each other. The LED circuit has the advantage of constant current of output current.

The embodiment of the present application provides an LED lighting circuit 10, which includes: a light emitting circuit 12 and a driving circuit 11.

The light emitting circuit 12 includes one light emitting cell L1 or a plurality of at least two light emitting cells L1 connected in series in sequence.

The drive circuit 11 includes: a power input 111, one or at least two first switching units Q1, and a current limiting circuit 113.

The power input terminal 111 is electrically connected to a first terminal of the light emitting circuit 12; the power input end 111 is used for being electrically connected with the output end 112 of the previous LED lighting circuit 10 or a power supply;

the number of the first switch units Q1 is the same as that of the light emitting units L1, the first switch units Q1 are in one-to-one correspondence with the light emitting units L1, each first switch unit Q1 is connected in parallel with a corresponding light emitting unit L1, and the first switch unit Q1 is used for controlling the electrical on-off state of the first switch unit Q1 according to an external control signal.

The first end of the current limiting circuit 113 is electrically connected to the second end of the light emitting circuit 12, the second end of the current limiting circuit 113 serves as the output end 112 of the LED lighting circuit 10, the output end 112 is electrically connected to the power input end 111 of the next LED lighting circuit 10 or grounded, and the current limiting circuit 113 is configured to limit the current flowing through the light emitting circuit 12 to a first preset value, where the first preset value of the current is smaller than or equal to the rated current of the light emitting unit L1.

In the present application, the number of the light emitting units L1 included in the light emitting circuit 12 is not limited, and may be 1, 2, 3, or the like. In the present application, the light-emitting circuit 12 is described as including three light-emitting cells L1 connected in series in sequence. The power rating, voltage rating, and current rating of each light emitting cell L1 may be the same or different. In the embodiment of the present application, the rated power, the rated voltage, and the rated current of the light emitting unit L1 are the same. The colors of the light emitted by the different light-emitting units L1 may be the same or different, and in the present application, the colors of the three light-emitting units L1 may be a first color, a second color, and a third color, respectively, and specifically, the first color may be red, the second color may be green, and the third color may be blue. In this application, light-emitting unit L1 can be LED, lamp pearl etc. can give out light can.

In this application, if the light emitting circuit 12 includes a light emitting unit L1, the first terminal of the light emitting unit L1 is used as the first terminal of the light emitting circuit 12, and the second terminal of the light emitting unit L1 is used as the second terminal of the light emitting circuit 12.

If the light emitting cells L1 include two or more, the light emitting cells L1 are sequentially connected in series. Specifically, the first terminal of the first light emitting cell L1 serves as the first terminal of the light emitting circuit 12, the first terminal of the subsequent light emitting cell L1 is electrically connected to the second terminal of the previous light emitting cell L1, and the second terminal of the last light emitting cell L1 serves as the second terminal of the light emitting circuit 12. The light emitting cells L1 are sequentially connected in series, so that the current flowing through each light emitting cell L1 is uniform, and the luminance of each light emitting cell L1 is also the same.

The driving circuit 11 may be an LED driving chip, and the driving circuit 11 may control one or more lighting units to emit light.

Optionally, the power input 111 is used as an input for power. The power input 111 may be a node, and an external power source supplies power to other circuits or components of the LED lighting circuit 10 through the power input 111. If a plurality of LED lighting circuits 10 are connected in series, the power input 111 of one LED lighting circuit 10 may be electrically connected to the output 112 of the previous LED lighting circuit 10, and the power input 111 of the first LED lighting circuit 10 may be electrically connected to an external power source.

The number of the first switching units Q1 is the same as the number of the light emitting units L1. When the light emitting circuit 12 includes three light emitting cells L1, the driving circuit 11 also includes three first switching cells Q1, and each first switching cell Q1 is connected in parallel with a corresponding light emitting cell L1.

Optionally, a first end of each first switch unit Q1 is electrically connected to a first end of the corresponding light emitting unit L1, a second end of each first switch unit Q1 is electrically connected to a second end of the corresponding light emitting unit L1, a third end of each first switch unit Q1 is electrically connected to an external second control circuit, and is configured to control an electrical on-off state between the first end and the second end of the first switch unit Q1 according to a second control signal of the second control circuit, and an electrical on-off state of any one first switch unit Q1 is the same as or different from an electrical on-off state of the other first switch units Q1.

When a first switch unit Q1 is electrically turned on, the light emitting unit L1 corresponding to the first switch unit Q1 stops working and does not emit light; when a first switch Q1 is turned off, the light emitting unit L1 corresponding to the first switch Q1 will emit light. Specifically, if the LED lighting circuit 10 includes three first switch units Q1 and three light emitting units L1, one of the three first switch units Q1 is electrically opened, and the other two first switch units Q1 are electrically closed, the light emitting unit L1 corresponding to the electrically opened first switch unit Q1 will operate to emit light, and the two light emitting units L1 corresponding to the two electrically closed first switch units Q1 respectively stop operating and do not emit light. When all the three first switches are electrically turned off, all the three light emitting units L1 will emit light.

Alternatively, the first switching unit Q1 may be a switching element, such as a mos Transistor (Metal-Oxide-Semiconductor Field-Effect Transistor, MOSFET, Metal-Oxide-Semiconductor Field-Effect Transistor, Field-Effect Transistor), a triode, an IGBT (insulated-Gate Bipolar Transistor), or the like. The polarity of the switching element is not limited, for example, the mos tube may be an N-type mos tube or a P-type mos tube. In the embodiment of the present application, the first switch unit Q1 is a mos transistor, the first end of the first switch unit Q1 is the first end of the first mos transistor, the second end of the first switch unit Q1 is the second end of the first mos transistor, and the third end of the first switch unit Q1 is the control end of the first mos transistor.

Optionally, the current limiting circuit 113 includes one current limiting unit Q2 or at least two parallel current limiting units Q2. The first end of each current limiting unit Q2 is electrically connected to the second end of the light emitting circuit 12, the second end of each current limiting unit Q2 is used as the output end 112, the third end of the current limiting unit Q2 is electrically connected to an external first control circuit, the current limiting unit Q2 is used for controlling the electrical conduction between the first end and the second end of the current limiting unit Q2 according to a first control signal of the first control circuit, when the first end and the second end of the current limiting unit Q2 are electrically conducted, the current allowed to pass between the first end and the second end of each current limiting unit Q2 is a second preset value, and the sum of the second preset values of at least one current limiting unit Q2 is the first preset value. The switching states of all the current limiting units Q2 are the same. When the LED lighting circuit 10 is in operation, all the current limiting circuits 113 are in an electrically conductive state.

When the current limiting circuit 113 includes at least two current limiting units Q2 connected in parallel, the first terminal of each current limiting unit Q2 is electrically connected to the second terminal of the lighting circuit 12, and the second terminals of all the current limiting units Q2 are commonly used as the output terminal 112 of the LED lighting circuit 12.

If the current limiting circuit 113 includes a current limiting unit Q2, the second preset value is the same as the first preset value. If the current limiting circuit 113 includes at least two current limiting units Q2, the sum of all the second preset values is the first preset value. Alternatively, when the current limiting circuit 113 includes at least two current limiting units Q2, the second preset values of the different current limiting units Q2 may be the same or different. Optionally, the second preset values of the different current limiting units Q2 are the same. Specifically, if the rated current of the light emitting unit L1 is 1A, the first preset value is 1A, and if the current limiting circuit 113 includes two current limiting units Q2, the second preset value of each current limiting unit Q2 may be 0.5A, and the sum of the second preset values of the two current limiting units Q2 is 0.5+0.5 — 1A.

Optionally, the current limiting unit Q2 is a current limiting switching unit, and the first end of the current limiting unit Q2 is a first end of the current limiting switching unit; the second terminal of the current limiting unit Q2 is the second terminal of the current limiting switch unit, and the third terminal of the current limiting unit Q2 is the control terminal of the current limiting switch unit.

Referring to fig. 2, the LED lighting circuit 10 further includes a clamping circuit 13, a first end of the clamping circuit 13 is electrically connected to the power input end 111, and a second end of the clamping circuit 13 is electrically connected to the output end 112.

The clamp circuit 13 is used to discharge when the voltage at the power input terminal 111 is too large, so that the current output from the LED lighting circuit 10 is substantially constant. If a light emitting unit L1 is damaged and the first switch unit Q1 corresponding to the damaged light emitting unit L1 is electrically disconnected, so that the damaged light emitting unit L1 needs to operate, the damaged light emitting unit L1 may cause the voltage at the power input end 111 to be too high, the clamp circuit 13 discharges, and if a plurality of LED lighting circuits 10 are connected in series, the clamp circuit 13 may enable other LED lighting circuits 10 to operate normally.

The clamp circuit 13 includes a voltage dividing unit 131, a second switching unit Q3, a comparing unit 132, and a first node 133.

A first terminal of the voltage dividing unit 131 is electrically connected to the power input terminal 111, a second terminal of the voltage dividing unit 131 is electrically connected to the output terminal 112, and a third terminal of the voltage dividing unit 131 is electrically connected to the first node 133.

A first terminal of the second switching unit Q3 is electrically connected to the power input terminal 111, and a second terminal of the second switching unit Q3 is electrically connected to the output terminal 112.

A first input terminal of the comparing unit 132 is electrically connected to the first node 133, an output terminal 112 of the comparing unit 132 is electrically connected to a third terminal of the second switching unit Q3, and a second input terminal of the comparing unit 132 is electrically connected to an external third control circuit. The comparing unit 132 is configured to control the first terminal and the second terminal of the second switching unit Q3 to be electrically connected when the voltage of the first input terminal is greater than the voltage of the second input terminal.

Alternatively, the positive power terminal of the comparing unit 132 is electrically connected to the power input terminal 111, and the negative power terminal of the comparing unit 132 is electrically connected to the output terminal 112.

The second switching unit Q3 may be a switching element, such as a mos transistor, a triode, an IGBT, or the like. The polarity of the switching element is not limited, for example, the mos tube may be an N-type mos tube or a P-type mos tube. In the embodiment of the present application, the second switch unit Q3 is a mos transistor, the first end of the second switch unit Q3 is the first end of the mos transistor, the second end of the second switch unit Q3 is the second end of the mos transistor, and the third end of the second switch unit Q3 is the control end of the mos transistor. Optionally, in this embodiment of the application, the larger the difference between the voltage of the first input terminal and the voltage of the second input terminal is, the larger the current that can pass between the first terminal and the second terminal of the second switching unit Q3 is.

The voltage dividing unit 131 includes: a first pressure-dividing unit R1 and a second pressure-dividing unit R2. A first end of the first voltage division unit R1 is electrically connected to the power input terminal 111; a second end of the second voltage division unit R2 is electrically connected to the output terminal 112; the second terminal of the first voltage dividing unit R1 and the first terminal of the second voltage dividing unit R2 are electrically connected to the first node 133 as the third terminal of the voltage dividing unit 131 in common.

Referring to fig. 3, the present application further provides a lighting circuit 20, which includes at least two LED lighting circuits 10 connected in series in sequence. The power input end of the first LED lighting circuit 10 is connected to an external power supply, the power input end of the subsequent LED lighting circuit 10 is electrically connected to the output end of the previous LED lighting circuit 10, and the output end of the last LED lighting circuit 10 is grounded. The appropriate number of LED lighting circuits 10 are connected in series such that the voltage shared by each LED lighting circuit 10 can be the rated voltage of the LED lighting circuit 10, such that the LED lighting circuit 10 can operate normally, and it is not necessary to adjust the voltage of the input power source in order to match the voltage of the LED lighting circuit 10.

Optionally, if more than 3 LED lighting circuits 10 are connected in series, the power input terminal of the first LED lighting circuit 10 is electrically connected to an external power supply; the output end of the last LED lighting circuit 10 is grounded; in any two adjacent LED lighting circuits 10, the output terminal of the previous LED lighting circuit 10 is electrically connected to the power input terminal of the next LED lighting circuit 10.

The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above examples only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present application. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application.

Claims (10)

1. An LED lighting circuit, comprising:

the light-emitting circuit comprises a light-emitting unit or at least two light-emitting units which are sequentially connected in series;

a drive circuit, the drive circuit comprising:

a power input end electrically connected with a first end of the light emitting circuit; the power supply input end is used for being electrically connected with the output end of the last LED lighting circuit or a power supply;

one or at least two first switch units, each of which is connected in parallel with a corresponding one of the light emitting units;

the current limiting circuit is used for limiting the current flowing through the light emitting circuit to be a first preset value, and the first preset value is smaller than or equal to the rated current of the light emitting unit.

2. The LED lighting circuit of claim 1, wherein: the current limiting circuit includes:

the current limiting unit is used for controlling the electrical conduction between the first end and the second end of the current limiting unit according to a first control signal of the first control circuit, when the first end and the second end of the current limiting unit are electrically conducted, the current allowed between the first end and the second end of each current limiting unit is a second preset value, and the sum of the second preset values of the at least one current limiting unit is the first preset value.

3. The LED lighting circuit of claim 2, wherein the current limiting unit is a current limiting switch unit, and the first end of the current limiting unit is a first end of the current limiting switch unit; the second end of the current limiting unit is the second end of the current limiting switch unit, and the third end of the current limiting unit is the control end of the current limiting switch unit.

4. The LED lighting circuit of claim 1, wherein the lighting circuit comprises three lighting units connected in series in sequence; the LED lighting circuit comprises three first switch units, each first switch unit is connected with one corresponding light-emitting unit in parallel, and the colors of light emitted by the three light-emitting units are respectively a first color, a second color and a third color.

5. The LED lighting circuit according to claim 1, wherein each of the first switch units has a first end electrically connected to the first end of the corresponding light-emitting unit, a second end electrically connected to the second end of the corresponding light-emitting unit, and a third end electrically connected to an external second control circuit, and is configured to control an electrical on-off state between the first end and the second end of the first switch unit according to a second control signal of the second control circuit, where the electrical on-off state of any one of the first switch units is the same as or different from the electrical on-off states of the other first switch units.

6. The LED lighting circuit of claim 1, wherein the first switching unit is a field effect transistor, a triode, or an insulated gate bipolar transistor.

7. The LED lighting circuit of claim 1, further comprising a clamping circuit, a first end of the clamping circuit being electrically connected to the power input, a second end of the clamping circuit being electrically connected to the output.

8. The LED lighting circuit of claim 7, wherein the clamping circuit comprises: the voltage divider unit, the second switch unit, the comparison unit and the first node;

the first end, the second end and the third end of the voltage division unit are respectively and electrically connected with the power input end, the output end and the first node;

the first end and the second end of the second switch unit are respectively and electrically connected with the power supply input end and the output end;

and the comparison unit is used for controlling the electrical conduction between the first end and the second end of the second switch unit when the voltage of the first input end is greater than the voltage of the second input end.

9. The LED lighting circuit according to claim 8, wherein the voltage dividing unit includes: a first voltage dividing unit and a second voltage dividing unit;

the first end of the first voltage division unit is electrically connected with the power supply input end;

the second end of the second voltage division unit is electrically connected with the output end;

the second end of the first voltage division unit and the first end of the second voltage division unit are jointly used as the third end of the voltage division unit and are electrically connected with the first node.

10. A lighting circuit, comprising: at least two LED lighting circuits according to any of claims 1-9 connected in series.

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