CN220123102U

CN220123102U - Power-down holding circuit and LED driving circuit

Info

Publication number: CN220123102U
Application number: CN202321689875.8U
Authority: CN
Inventors: 刁显江
Original assignee: Opple Lighting Co Ltd; Suzhou Op Lighting Co Ltd
Current assignee: Opple Lighting Co Ltd; Suzhou Op Lighting Co Ltd
Priority date: 2023-06-29
Filing date: 2023-06-29
Publication date: 2023-12-01
Anticipated expiration: 2033-06-29

Abstract

The utility model provides a power-down holding circuit and an LED driving circuit, wherein the power-down holding circuit comprises: the driving module converts the voltage of the AC end; the input end of the voltage reducing module is connected with the driving module and is configured to convert the voltage of the driving module; a communication module configured to communicate with the outside; the control module is connected with the driving module and is configured to control the operation of the driving module; the output end of the voltage reducing module is respectively connected with the input end of the communication module and the input end of the control module, and the voltage reducing module is configured to provide voltage for the control module and the communication module; the step-down module comprises a MOS line, and the control module controls the step-down module to start/stop supplying power to the communication module by controlling the on/off of the MOS line. After the control module of the power-down maintaining circuit detects that the AC end is powered down, the voltage reduction module is controlled to stop supplying power to the communication module, the consumption of residual voltage in the driving module is reduced, and the working time of the control module after the AC end is powered down is prolonged.

Description

Power-down holding circuit and LED driving circuit

Technical Field

The utility model relates to the field of illumination, in particular to a power-down holding circuit and an LED driving circuit.

Background

With the improvement of living standard, the LED illumination is increasingly applied to a plurality of scenes, wherein the intelligent illumination is also increasingly widely used in the actual life of people, and people meet more use demands by controlling the LED lamp.

The intelligent illumination can conveniently adjust the color temperature, the current and the like of the LED lamp through various control modes such as Bluetooth, WIFI, PLC, DALI,0-10V and the like, and the application scene and the requirement of people on diversity are met. In intelligent illumination, communication is generally performed with the outside in a mode of a communication module (Bluetooth, WIFI, PLC, DALI,0-10V and the like), external control information is transmitted to an MCU, and the MCU converts the transmitted control information into PWM signals to control the working state of the drive. The MCU driven by the power supply can keep working for a period of time (generally more than 3S) after the power supply is powered off, so that the MCU can conveniently process part of information. The MCU and the control module are generally integrally powered, the power consumption of the MCU is small, the power consumption of the control module is high, and after the mains supply is cut off, the power consumption of the control module can influence the power supply of the MCU to cause insufficient power failure holding time (the power failure holding time is defined as the continuous working time of the MCU after the AC is powered off). The common practice is to enlarge the input/output capacitance of the power supply circuit to meet the power failure holding time, so that the added capacitance capacity is larger, and the driving volume and cost are increased.

In view of the foregoing, it is necessary to provide a power-down holding circuit and an LED driving circuit to solve the above-mentioned problems.

Disclosure of Invention

The utility model aims to provide a power-down holding circuit and an LED driving circuit.

To achieve the above object, the present utility model provides a power-down holding circuit comprising:

the driving module is connected with the AC end and used for converting the voltage of the AC end;

the input end of the voltage reduction module is connected with the driving module and is configured to convert the voltage of the driving module;

a communication module configured to communicate with the outside;

the control module is connected with the driving module and is configured to control the operation of the driving module;

the output end of the voltage reduction module is respectively connected with the input end of the communication module and the input end of the control module, and the voltage reduction module is configured to provide voltage for the control module and the communication module; the output end of the control module is connected with the voltage reducing module, the voltage reducing module comprises a MOS line, and the control module controls the voltage reducing module to start/stop supplying power to the communication module by controlling the on/off of the MOS line.

As a further improvement of the utility model, the voltage reducing module comprises a high-voltage reducing module and a secondary voltage reducing module, wherein the input end of the high-voltage reducing module is connected with the driving module, and the output end of the high-voltage reducing module is respectively connected with the input end of the stage voltage reducing module.

As a further improvement of the present utility model, the output ends of the secondary voltage reduction module are respectively connected with the input ends of the control module and the communication module, and are configured to provide working voltages for the control module and the communication module.

As a further improvement of the present utility model, the secondary step-down module includes the MOS line, and an output end of the control module is connected to the secondary step-down module, and the control module outputs a high/low level to realize on/off of the MOS line.

As a further improvement of the utility model, the secondary voltage reduction module comprises a voltage stabilizing chip, a third capacitor, a second capacitor, a ninth resistor, a tenth resistor, an eleventh resistor, a MOS tube and a triode, wherein the voltage stabilizing chip, the third capacitor and the second capacitor form a linear voltage stabilizing circuit for supplying power to the control module; and the ninth resistor, the tenth resistor, the eleventh resistor, the MOS tube and the triode form a controlled MOS circuit to control the secondary voltage dropping module to supply power for the communication module.

As a further improvement of the utility model, the power-down holding circuit further comprises a power-down detection module, wherein the input end of the power-down detection module is connected with the AC end, and the output end of the power-down detection module is connected with the input end of the control module; when the control module detects that the power failure detection module generates voltage, the control module controls the voltage reduction module to start providing working voltage to the communication module; when the control module detects that the voltage of the power failure detection module is zero, the control module controls the voltage reduction module to stop providing working voltage to the communication module.

As a further improvement of the utility model, the power-down holding circuit further comprises a power-down detection module, and the input end of the power-down detection module can be connected with any one or two of the L line or the N line of the AC end.

As a further improvement of the present utility model, the driving module includes a driving capacitor for maintaining the control module in operation after the AC terminal is powered down.

Another object of the present utility model is to provide an LED driving circuit including the above power-down holding circuit.

In order to achieve the above object, the present utility model provides an LED driving circuit, including the power-down holding circuit described above.

As a further improvement of the utility model, the LED driving circuit comprises a driving module, the driving module comprises two paths of output ends, one output end of the driving module is connected with the warm-color LED lamp beads, the other output end of the driving module is connected with the cold-color LED lamp beads, the warm-color LED lamp beads and the cold-color LED lamp beads can be independently output under the control of the driving module, and mixed colors can also be simultaneously output.

The beneficial effects of the utility model are as follows: compared with the prior art, the power-down maintaining circuit has the advantages that after the control module detects that the AC end is powered down, the voltage reduction module is controlled to stop supplying power to the communication module, so that the consumption of residual voltage in the driving module is reduced, only the control module continuously consumes energy, the working time of the control module after the AC end is powered down is greatly prolonged under the condition that the driving capacitance in the driving module is not increased through logic control, and the power-down maintaining circuit has good practicability and economy.

Drawings

Fig. 1 is a functional block diagram of a power down holding circuit in accordance with a preferred embodiment of the present utility model.

Fig. 2 is a circuit diagram of a driving module in the power-down holding circuit of the present utility model.

Fig. 3 is a circuit diagram of the step-down module, the control module, and the communication module in the power-down holding circuit in a preferred embodiment of the present utility model.

Fig. 4 is a functional block diagram of a power down holding circuit in accordance with another preferred embodiment of the present utility model.

Fig. 5 is a circuit diagram of a step-down module, a control module, and a communication module in a power-down holding circuit according to another preferred embodiment of the present utility model.

100-a power-down holding circuit;

10-a driving module; 20-a step-down module, 21-a high-voltage step-down module, 22-a first secondary step-down module, 23-a second secondary step-down module, 24-a secondary step-down module; 30-a control module; 40-a communication module; 50-a power-down detection module.

Detailed Description

In order to make the objects, technical solutions and advantages of the present utility model more apparent, the present utility model will be described in detail with reference to the accompanying drawings and specific embodiments.

In this case, in order to avoid obscuring the present utility model due to unnecessary details, only the structures and/or processing steps closely related to the aspects of the present utility model are shown in the drawings, and other details not greatly related to the present utility model are omitted.

In addition, it should be further noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

Referring to fig. 1-2, a power-down holding circuit 100 according to the present utility model is shown, the power-down holding circuit 100 includes:

the driving module 10 is connected with the AC end and converts the voltage of the AC end;

the input end of the voltage reducing module 20 is connected with the driving module 10 and is configured to convert the voltage of the driving module 10;

a communication module 40 configured to communicate with the outside;

a control module 30, coupled to the drive module 10, configured to control operation of the drive module 10;

the output end of the voltage reducing module 20 is respectively connected with the input end of the communication module 40 and the input end of the control module 30, and the voltage reducing module 20 is configured to provide voltage to the control module 30 and the communication module 40; an output terminal of the control module 30 is connected to the voltage reducing module 20, and the control module 30 controls the voltage reducing module 20 to start/stop supplying power to the communication module 40.

The driving module 10 is used for converting the commercial power into voltage and current which can be used by the LED lamp, and the driving module 10 can output in a single way or in multiple ways; the control module 30 functions as communication, signal sampling, logic control and PWM signal conversion; the communication module 40 is used for converting the requirements of users through various control modes such as Bluetooth, WIFI, PLC, DALI,0-10V and the like and then communicating with the control module 30. The driving module 10, the control module 30 and the communication module 40 are all not limited by topology architecture, scheme, manufacturer, chip model and working mode.

When the AC is powered on, the driving module 10 converts the commercial power at the AC end into a voltage that can be used by the LED lamp, the step-down module 20 takes power from the driving module 10 and converts the power into a low voltage, the low voltage is converted into a working voltage, the working voltage is respectively provided for the control module 30 and the communication module 40, the communication module 40 and the control module 30 normally start to work, the communication module 40 receives an external control demand and sends the external control demand to the control module 30 after converting, and the control module 30 outputs a PWM signal to control the driving module 10 to work.

When the AC end is powered down, the driving module 10 stops working, no power input is provided from the outside, the residual voltage in the driving module 10 is continuously supplied to the voltage reduction module 20 to get power, at this time, after the control module 30 detects that the AC end is powered down, the control module 30 controls the voltage reduction module 20 to stop supplying power to the communication module 40, the communication module 40 stops working and does not continuously consume energy, the residual voltage loss in the driving module 10 is reduced, only the control module 30 continuously consumes energy, and the control module 30 can continuously work for a longer time after the AC end is powered down.

In some embodiments, buck module 20 further includes an EN pin, and an output of control module 30 is connected to EN pin of buck module 20, and control module 30 controls buck module 20 to start/stop supplying power to communication module 40 via EN pin of buck module 20.

The output terminal of the control module 30 is connected to the EN pin of the voltage reducing module 20, when the control module 30 outputs a high level to the EN pin, the EN pin is activated, the voltage reducing module 20 starts to supply power to the communication module 40, and when the control module 30 outputs a low level, the EN pin is not activated, the voltage reducing module 20 stops supplying power to the communication module 40.

The power-down holding circuit 100 further comprises a power-down detection module 50, wherein an input end of the power-down detection module 50 is connected with the AC end, and an output end of the power-down detection module 50 is connected with an input end of the control module 30; when the control module 30 detects that the power failure detection module 50 generates voltage, the control module 30 controls the voltage reduction module 20 to start providing working voltage to the communication module 40, that is, the control module 30 outputs a high level to the EN pin of the voltage reduction module 20; when the control module 30 detects that the voltage of the power failure detection module 50 is zero, the control module 30 controls the voltage step-down module 20 to stop supplying the operating voltage to the communication module 40, that is, the control module 30 outputs a low level to the EN pin of the voltage step-down module 20.

The buck module 20 includes a high-voltage buck module 21, a first secondary buck module 22 and a second secondary buck module 23, wherein an input end of the high-voltage buck module 21 is connected with the driving module 10, and an output end of the high-voltage buck module 21 is respectively connected with an input end of the first secondary buck module 22 and an input end of the second secondary buck module 23.

The high voltage step-down module 21 is connected into the driving module 10 to convert the higher voltage in the driving module 10 into a low voltage. This buck module 20 may be of any suitable power topology, not limited to a switching power architecture or a linear architecture, nor to a model number. The first secondary step-down module 22 and the second secondary step-down module 23 are linear voltage stabilizing modules, and are used for converting the voltage provided by the high-voltage step-down module 21 into the voltage which can be used by the control module 30 and the signal module, and the voltage is not limited by the manufacturer and the model of the chip used.

The output end of the first secondary step-down module 22 is connected with the control module 30, the output end of the control module 30 is connected with the EN pin of the first secondary step-down module 22, and the control module 30 controls the first secondary step-down module 22 to start/stop providing voltage to the control module 30 through the EN pin. The first secondary buck module 22 includes a linear LDO chip with an EN pin function, the control module 30 can control on and off of the first secondary buck module 22 through the EN pin, the EN pin is activated when the control module 30 inputs a high level to the EN pin of the first secondary buck module 22, the first secondary buck module 22 starts to supply power to the communication module 40, and the first secondary buck module 22 stops supplying power to the communication module 40 when the control module 30 inputs a low level to the EN pin of the first secondary buck module 22.

An output of the second secondary buck module 23 is connected to an input of the control module 30 and is configured to provide an operating voltage to the control module 30.

As shown in fig. 4, in some embodiments, the output of the control module 30 is connected to the buck module 20, the buck module 20 includes a MOS line, and the control module 30 controls the buck module 20 to start/stop supplying power to the communication module 40 by controlling on/off of the MOS line.

The step-down module 20 includes a high-voltage step-down module 21 and a secondary step-down module 24, wherein an input end of the high-voltage step-down module 21 is connected with the driving module 10, and an output end of the high-voltage step-down module 21 is respectively connected with an input end of the step-down module 20.

The high voltage step-down module 21 is connected into the driving module 10 to convert the higher voltage in the driving module 10 into a low voltage. This buck module 20 may be any suitable power topology, not limited to a switching power architecture or a linear architecture, nor to a model number; the secondary voltage step-down module 24 is used to convert the voltage provided by the high voltage step-down module 21 into a voltage usable by the control module 30 and the signal module, and is not limited to the manufacturer and model of the chip used.

The output ends of the secondary step-down module 24 are respectively connected with the input ends of the control module 30 and the communication module 40, and are configured to provide working voltages for the control module 30 and the communication module 40.

The secondary step-down module 24 includes a MOS line, and an output terminal of the control module 30 is connected to the secondary step-down module 24, and the control module 30 outputs a high/low level to turn on/off the MOS line.

When the control module 30 detects that the voltage input by the power failure detection module 50 is greater than zero, the control module 30 outputs a high level to the secondary step-down module 24, at this time, the MOS line is turned on, and the secondary step-down module 24 starts to supply power to the communication module 40; when the control module 30 detects that the voltage input from the power-down detection module 50 is zero, the control module 30 outputs a low level to the secondary step-down module 24, at which time the MOS line is disconnected, and the secondary step-down module 24 stops supplying power to the communication module 40.

The secondary step-down module 24 includes a voltage stabilizing chip U1, a third capacitor C3, a second capacitor C2, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a MOS transistor Q1, and a triode Q2, where the voltage stabilizing chip U1, the third capacitor C3, and the second capacitor C2 form a linear voltage stabilizing circuit to supply power to the control module 30; the ninth resistor R9, the tenth resistor R10, the eleventh resistor R11, the MOS transistor Q1, and the triode Q2 form a controlled MOS line to control the secondary step-down module 24 to supply power to the communication module 40.

The input of the power down detection module 50 may be connected to either or both of the L or N lines of the AC terminal.

The power failure detection module 50 is connected to the AC end of the mains supply, and may be connected to each of the single lines L and N, or may be connected to the double lines, and is used for detecting the power failure state of the AC end, and when the AC end is turned off and no voltage is applied, the signal is transmitted to the control module 30 for processing.

The drive module 10 includes a drive capacitor for maintaining the control module 30 in operation after the AC terminal is powered down. After the AC terminal is powered down, the driving module 10 stops working, no power is input from the outside, and a part of voltage remains in the driving capacitor of the driving module 10 to maintain the control module 30 to continue working.

In this embodiment, the control module 30 is an MCU controller, and in other embodiments, other control devices may be used, which is not limited in this aspect of the utility model.

The utility model also provides an LED driving circuit, which comprises the power-down maintaining circuit 100.

This LED drive circuit includes drive module 10, and drive module 10 includes two way output, and one of them output termination warm color LED lamp pearl, another output termination cold color LED lamp pearl, warm color LED lamp pearl and cold color LED lamp pearl receive drive module 10's control ability independent output, also can output the colour mixture simultaneously, can satisfy the user demand of different application scenes.

Fig. 1 to 3 show an LED driving circuit according to an embodiment of the present utility model.

Intelligent LEDs controlled by WIFI drive two paths of outputs, and the LEDs with warm colors and cold colors are connected. The device comprises a driving module 10, a power failure detection module 50, an MCU, a communication module 40, a first secondary voltage reduction module 22, a second secondary voltage reduction module 23 and a high voltage reduction module 21. The input end of the drive is L, N is connected with AC commercial power, the output end of the drive is LED+, LEDW-is connected with the LED lamp bead of warm color, and LED+ and LEDCC-are connected with the LED lamp bead of cool color. The two paths of warm colors and the cold color LED lamp beads can be independently output under the control of the driving module 10, can also simultaneously output mixed colors, and can change the output current to change the output brightness. The whole LED driving circuit has the functions of dimming and toning, and meets the requirements of different application scenes.

The driving module 10 is used for converting the input commercial power into voltage and current suitable for driving the LEDs, and the PWM pins of the driving chips U4 and U7 are connected through external PWM signals, so that the output current can be adjusted, and in this embodiment, the driving of PWM dimming of the single-stage low-PF BUCK architecture can be implemented by a two-stage architecture (boost+buck), a single-stage high-PF BUCK architecture, or any other suitable constant current architecture. As long as the architecture can drive the LED with constant current output, and the output current of the drive can be regulated by PWM.

The communication module 40 is used for converting external requirements such as dimming and color mixing and then communicating with the MCU, and in this embodiment, the communication module is WIFI controlled, in other embodiments, other control schemes (bluetooth, DALI,0-10v, plc, etc.) may be used, and the control scheme is not limited, so long as the communication scheme CAN be used to communicate with the MCU, in this embodiment, the communication mode with the MCU is I2C, in other embodiments, the communication modes may also be various, and the utility model is not limited thereto.

The MCU is operative to communicate with the communication module 40, output PWM control drives, AC side detection, control operation of the first secondary buck module 22, and other logic detection and control. In this embodiment, the singlechip has 2 paths of PWM, respectively PWMW and PWMC, corresponding to PWM ports of two paths of chips of the driving module 10. The PIN14 of the MCU is connected with a CP signal to detect the working condition of an AC end. MCU PIN2 can output high or low level, connects first secondary step-down module 22 chip U3's EN foot, and U3 works when PIN2 output is high, and U3 stops working when PIN2 output low level, and MCU's PIN still is responsible for other logic control functions.

The high-voltage step-down module 21 functions to output 5V voltage and then supply the output to the first secondary step-down module 22 and the second secondary step-down module 23. In this embodiment, the high voltage step-down module 21 is connected to the VBUS of the rectifier bridge of the driving module 10, and can convert the high voltage signal into 5V. In this embodiment, the BUCK architecture may be any of various architectures, a switching power supply scheme, or a linear scheme, so long as the BUCK power supply can convert high voltage into low voltage, and the vendor and model are not limited. The power-taking position of the high-voltage step-down module 21 is various, and the power-taking position can be taken from the VBUS after the rectifier bridge, or other suitable places, according to the topological structure of the module.

The first secondary step-down module 22 is connected to the end of the high-voltage step-down module 21 and outputs 3.3V voltage to the communication module 40; the first secondary voltage reduction module 22 has a linear voltage stabilizing structure, and the chip U3 of the first secondary voltage reduction module 22 is not limited by manufacturers and models. U3 PIN3 is the EN PIN, and when EN PIN voltage was high level, the circuit work was converted 5V to 3.3V, and when EN PIN voltage was low level, the circuit was not worked, output 0V.

The second secondary step-down module 23 is connected to the high-voltage step-down module 21 end and outputs 3.3V voltage to the MCU. The voltage stabilizing chip U1 of the second secondary voltage reducing module 23 is not limited to a manufacturer and is not limited to a model number.

The power failure detection module 50 is composed of a seventh resistor R7 and an eighth resistor R8, and the voltage of the AC end can be reduced to Pin14 of the MCU U6 in an equal proportion through reasonable voltage division. In this embodiment, the seventh resistor R7 is connected to the N line of the AC end, or may be connected to the L line, or may be connected to the L and N double lines, but when the double lines are connected, a diode needs to be connected in series to the upper end of the electron to prevent short circuit.

The working process of the LED driving circuit is as follows:

when the AC terminal is powered on, the high-voltage step-down module 21 works to generate 5V, the second secondary step-down module 23 takes power from the high-voltage step-down module 21 and converts the power into 3.3V of MCU working voltage, the MCU normally starts working, 2 paths of PWM signals are output to control the driving module 10 to work, the MCU PIN2 outputs high level to the chip U3 PIN3 of the first secondary step-down module 22, the U3 generates 3.3V to the communication module 40U5, the chip U5 of the communication module 40 starts communicating with the outside, the outside requirement is converted to the MCU, and the MCU and the communication module 40 communicate with the conversion requirement to control the driving module 10. The MCU detects the state of the voltage divided by the seventh resistor R7 and the eighth resistor R8 of the power failure detection module 50 in real time.

After the power of the AC end is lost, the driving module 10 stops working, no power is input from the outside, but the third electrolytic capacitor EC3, the second electrolytic capacitor EC2, the third capacitor C3, the fourth capacitor C4 and the second capacitor C2 in the voltage reducing module 20 have residual voltages, and the MCU can be continuously maintained to work, and the voltage after the voltage division of the seventh resistor R7 and the eighth resistor R8 of the power failure detection module 50 is 0V. The U5 of the MCU outputs low level control through the PIN2 PIN to stop the chip U3 of the first secondary step-down module 22, so that the communication module 40 stops working and consumes no energy. The consumption of the residual voltage of the capacitor becomes low, the overall loss is only the loss of the MUC module, and the consumption of the MCU is usually much smaller than that of the communication module 40, so that the MCU can last longer. If such logic switching is not performed, the MCU and the control module 30 work simultaneously after power failure, and the residual voltage in the driving capacitor can be consumed quickly, so that the requirement of power failure holding time can not be met.

Fig. 2 and fig. 4 to 5 show an LED driving circuit according to another embodiment of the utility model.

The driving module 10 is used for converting the input AC mains supply into a voltage and a current suitable for driving the LED, and the output current can be regulated by connecting an external PWM signal to the PWM pins of the driving chip U4 and the chip U7, which is the PWM dimming driving of the single-stage low PF BUCK architecture in this embodiment, and may be a two-stage architecture (boost+buck) in other embodiments, or a single-stage high PF BUCK architecture, or any other suitable constant current architecture. As long as the architecture can drive the LED with constant current output, and the output current of the drive can be regulated by PWM.

The MCU is operative to communicate with the communication module 40, output PWM control drives, AC side detection, control operation of the secondary buck module 24, and other logic detection and control. In this embodiment, the singlechip has 2 paths of PWM, respectively PWMW and PWMC, corresponding to PWM ports of two paths of chips of the driving module 10. The PIN14 of the MCU is connected to the CP signal to detect the AC operating condition of the input. MCU PIN2 can output high or low level, receive NPN triode Q2's B pole through tenth resistance R10, when MCU PIN2 output high level, triode Q2 switches on, pulls the G pole of MOS pipe Q1 to 0V, Q1 switches on, 3.3V provides communication module 40, when PIN2 output low level, triode Q2B pole voltage is 0V, triode Q2 does not switch on, Q1G is extremely high level, Q1 does not switch on, 3.3V can not provide communication module 40.

The high-voltage step-down module 21 functions to output 5V voltage to the secondary step-down module 24. In this embodiment, the high voltage step-down module 21 is connected to the VBUS of the rectifier bridge of the driving module 10, and can convert the high voltage signal into 5V. In this embodiment, the BUCK architecture may be any of a variety of architectures, and may be a switching power supply scheme or a linear scheme. The manufacturer and model are not limited as long as the high voltage can be converted into the low voltage. The power taking position is various, and the power can be taken from the VBUS after the rectifier bridge, or other suitable places, according to the topological structure of the module.

The secondary step-down module 24 includes an LDO voltage stabilizing chip U1, a third capacitor C3, a second capacitor C2, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a MOS transistor Q1, and a PNP triode Q2. The voltage stabilizing chip U1, the third capacitor C3 and the second capacitor C2 form a linear voltage stabilizing circuit to convert 5V into 3.3V. The 3.3V is directly supplied to the MCU for power supply, and is connected to the MOS tube Q1, the ninth resistor R9, the tenth resistor R10, the eleventh resistor R11 and the triode Q2 to form a controlled MOS on-off line, and then connected to the communication module 40. When the MCU PIN2 output is high, the line work provides 3.3V power to the communication module 40. When the MCU PIN2 output is low level, the circuit is not operated, 0V is output, and the communication module 40 is powered off to stop operation.

The power failure detection module 50 is composed of a seventh resistor R7 and an eighth resistor R8, and the voltage of the AC end can be reduced to Pin14 of the MCU U6 in an equal proportion through reasonable voltage division. In this embodiment, the seventh resistor R7 is connected to the N line or the L and N double lines, but when the double lines are connected, a diode needs to be connected in series to the upper end of the electron to prevent short circuit.

The working process of the LED driving circuit is as follows:

when the AC is electrified, the high-voltage step-down module 21 works to generate 5V, the secondary step-down module 24 takes electricity from the high-voltage step-down module 21 and converts the electricity into MCU working voltage of 3.3V, the MCU normally starts working, 2 paths of PWM signals are output to control the driving module 10 to work, MCU PIN2 outputs high level to the pole Q2B of the triode, the pole Q2 is conducted to pull the pole Q1G of the MOS tube low, the MOS tube Q1 is conducted, 3.3V is supplied to the communication module 40 to start working, the communication module 40U5 starts communicating with the outside, the outside requirement is converted to the MCU, and the MCU and the communication module 40 communicate the conversion requirement to control the driving module 10. The MCU detects the state of the voltage divided by the seventh resistor R7 and the eighth resistor R8 of the power failure detection module 50 in real time.

After the AC end is powered down, the driving module 10 stops working, no power is input from the outside, but the third electrolytic capacitor E C, the second electrolytic capacitor EC2, the third capacitor C3, the fourth capacitor C4 and the second capacitor C2 in the voltage reducing module 20 still have residual voltages, and the MCU can be continuously maintained to work, and the voltage after the voltage division of the seventh resistor R7 and the eighth resistor R8 of the power failure detection module 50 is 0V. MCU outputs low level through PIN2 foot for triode Q2B extremely, and triode Q2 does not switch on, and MOS pipe Q1G extremely high level, and MOS pipe Q1 does not switch on, and communication module 40 loses the power, then communication module 40 stop work, does not consume the energy. The consumption of the residual voltage of the capacitor becomes low, the overall loss is only the loss of the MUC module, and the consumption of the MCU is usually much smaller than that of the communication module 40, so that the MCU can continuously work for a long time, and the requirement of power-down holding time is met.

In summary, in the power-down holding circuit 100 of the present utility model, after the control module 30 detects that the AC terminal is powered down, the voltage-reducing module 20 is controlled to stop supplying power to the communication module 40, so that the consumption of the residual voltage in the driving module 10 is reduced, only the control module 30 continues to consume energy, and through logic control, the working time of the control module 30 after the AC terminal is powered down is greatly prolonged without increasing the driving capacitance in the driving module 10, so that the power-down holding circuit has better practicability and economy.

The above embodiments are only for illustrating the technical solution of the present utility model and not for limiting the same, and it should be understood by those skilled in the art that the technical solution of the present utility model may be modified or substituted without departing from the spirit and scope of the technical solution of the present utility model.

Claims

1. A power down holding circuit, comprising:

the driving module (10) is connected with the AC end and used for converting the voltage of the AC end;

the input end of the voltage reduction module (20) is connected with the driving module (10) and is configured to convert the voltage of the driving module (10);

a communication module (40) configured to communicate with the outside;

a control module (30), coupled to the drive module (10), configured to control operation of the drive module (10);

the output end of the voltage reducing module (20) is respectively connected with the input end of the communication module (40) and the input end of the control module (30), and the voltage reducing module (20) is configured to provide voltages for the control module (30) and the communication module (40); the output end of the control module (30) is connected with the voltage reducing module (20), the voltage reducing module (20) comprises a MOS line, and the control module (30) controls the voltage reducing module (20) to start/stop supplying power to the communication module (40) by controlling the on/off of the MOS line.

2. The power failure holding circuit according to claim 1, wherein the voltage step-down module (20) includes a high-voltage step-down module (20) and a secondary voltage step-down module (24), an input end of the high-voltage step-down module (20) is connected to the driving module (10), and an output end of the high-voltage step-down module (20) is connected to an input end of the stage step-down module (20), respectively.

3. The power down holding circuit according to claim 2, wherein the output of the secondary voltage step-down module (24) is connected to the input of the control module (30) and the communication module (40), respectively, and is configured to provide an operating voltage to the control module (30) and the communication module (40).

4. The power down holding circuit according to claim 2, wherein the secondary step-down module (24) includes the MOS line, an output terminal of the control module (30) is connected to the secondary step-down module (24), and the control module (30) realizes on/off of the MOS line by outputting a high/low level.

5. The power failure holding circuit according to claim 2, wherein the secondary voltage reduction module (24) comprises a voltage stabilizing chip (U1), a third capacitor (C3), a second capacitor (C2), a ninth resistor (R9), a tenth resistor (R10), an eleventh resistor (R11), a MOS transistor (Q1), and a triode (Q2), wherein the voltage stabilizing chip (U1), the third capacitor (C3), and the second capacitor (C2) form a linear voltage stabilizing circuit to supply power to the control module (30); the ninth resistor (R9), the tenth resistor (R10) and the eleventh resistor (R11), the MOS tube (Q1) and the triode (Q2) form the controlled MOS circuit to control the secondary voltage dropping module (24) to supply power for the communication module (40).

6. The power down holding circuit according to claim 1, further comprising a power down detection module (50), an input of the power down detection module (50) being connected to an AC terminal, an output of the power down detection module (50) being connected to an input of the control module (30); when the control module (30) detects that the power failure detection module (50) generates voltage, the control module (30) controls the voltage reduction module (20) to start providing working voltage to the communication module (40); when the control module (30) detects that the voltage of the power failure detection module (50) is zero, the control module (30) controls the voltage reduction module (20) to stop supplying the working voltage to the communication module (40).

7. The power down holding circuit according to claim 1, further comprising a power down detection module (50), an input of the power down detection module (50) being connectable to either or both of the L-line or N-line of the AC-terminal.

8. The power down holding circuit according to claim 1, wherein the drive module (10) comprises a drive capacitor for maintaining the control module (30) in operation after the AC terminal is powered down.

9. An LED driving circuit comprising the power-down holding circuit according to any one of claims 1 to 8.

10. The LED driving circuit according to claim 9, characterized in that the LED driving circuit comprises a driving module (10), the driving module (10) comprises two output ends, one output end is connected with a warm color LED lamp bead, the other output end is connected with a cold color LED lamp bead, the warm color LED lamp bead and the cold color LED lamp bead can be independently output under the control of the driving module (10), and mixed colors can be simultaneously output.