Circuit for realizing no afterglow of non-isolated driving power supply during lamp turning-off

Abstract

The utility model relates to the field of lighting power supplies, and provides a non-isolated driving power supply light-off non-afterglow circuit comprising a driving power supply, the positive electrode of the driving power supply is electrically connected with the first input end of a DC-DC step-down output circuit, and the negative electrode of the driving power supply is electrically connected with one end of a non-afterglow circuit; the other end of the afterglow-free circuit is electrically connected with the second output end of the DC-DC voltage reduction output circuit; the non-afterglow circuit comprises a silicon controlled rectifier, and the anode of the silicon controlled rectifier is electrically connected with the second output end of the DC-DC voltage reduction output circuit. The first output end of the DC-DC voltage reduction output circuit is electrically connected with the positive electrode of the LED lamp panel, and the negative electrode of the LED lamp panel is electrically connected with the second output end of the DC-DC voltage reduction output circuit. And the afterglow-free circuit and the DC-DC voltage reduction output circuit are respectively connected with an external dimming turn-off control circuit.

Description

Technical Field

[0001] This application relates to the field of lighting power supplies, and in particular to a circuit for realizing a non-isolated drive power supply with no afterglow when the light is turned off. Background Technology

[0002] Currently, LED drivers for industrial and mining lamps, stadium lights, and plant lighting applications often use non-isolated power supplies, which offer advantages such as low cost and high energy efficiency. However, non-isolated solutions, which do not require additional circuitry, have an inherent drawback: after dimming and turning off the lights, the LEDs continue to glow faintly, exhibiting a "afterglow" phenomenon.

[0003] To achieve zero-afterglow requirements in specific applications, either a double-pole relay is added to physically disconnect the output terminals of the BUCK circuit, or a switching element (such as a MOSFET) is added to the other path of the BUCK circuit that does not have a switching element to control the output and input isolation. Using a relay is costly and space-consuming; using a MOSFET requires increasing the MOSFET's voltage rating for higher input voltages, which also increases cost. Utility Model Content

[0004] This application proposes a circuit for achieving afterglow-free operation when a non-isolated driver power supply turns off an LED. It utilizes a cost-effective high-voltage thyristor connected in series in the output ground loop. After dimming, the thyristor disconnects the input and output grounds, effectively cutting off the LED's connection to the input. The package size is similar to a MOSFET, requiring minimal space.

[0005] This application proposes a circuit for achieving afterglow-free operation when turning off lights using a non-isolated drive power supply, comprising:

[0006] The positive terminal of the drive power supply is electrically connected to the first input terminal of the DC-DC step-down output circuit, and the negative terminal of the drive power supply is electrically connected to one end of the non-persistent circuit.

[0007] The other end of the non-persistent circuit is electrically connected to the second output terminal of the DC-DC step-down output circuit; wherein, the non-persistent circuit includes a thyristor, and the anode of the thyristor is electrically connected to the second output terminal of the DC-DC step-down output circuit;

[0008] The first output terminal of the DC-DC step-down output circuit is electrically connected to the positive terminal of the LED board, and the negative terminal of the LED board is electrically connected to the second output terminal of the DC-DC step-down output circuit.

[0009] The afterglow-free circuit and the DC-DC step-down output circuit are also connected to an external dimming shutdown control circuit.

[0010] Furthermore, the afterglow-free circuit further includes: a first MOSFET, a third transistor, a fourth transistor, a first resistor, a second resistor, and a third resistor; wherein,

[0011] One end of the first resistor is connected to an external dimming and shutdown control circuit, and the other end of the first resistor is electrically connected to the base of the fourth transistor.

[0012] The collector of the fourth transistor is electrically connected to the gate of the first MOSFET, one end of the second resistor, and one end of the third resistor. The emitter of the fourth transistor is connected to the thyristor cathode and the source of the first MOSFET.

[0013] The drain of the first MOSFET is connected to the control electrode of the thyristor and the collector of the third transistor, respectively.

[0014] The base of the third transistor is electrically connected to the other end of the second resistor, and the emitter of the third transistor is electrically connected to the second power supply port.

[0015] The other end of the third resistor is electrically connected to the first power supply port.

[0016] Furthermore, the driving power supply is a DC power supply.

[0017] Furthermore, the DC-DC step-down circuit includes: a first MOSFET, a first diode, a fourth resistor, a transformer, a first polarized capacitor, and a second polarized capacitor;

[0018] The drain of the first MOSFET is connected to the positive terminal of the power supply and to the negative terminal of the power supply through the first polarized capacitor. The source of the first MOSFET is connected to one end of the transformer through the fourth resistor, and the other end of the transformer is electrically connected to the positive terminal of the LED board.

[0019] The positive terminal of the first diode is connected to the positive terminal of the thyristor and the negative terminal of the LED board, and the negative terminal of the first diode is connected to the source of the first MOSFET.

[0020] A second polarity resistor is connected in parallel between the positive and negative terminals of the LED light board.

[0021] Furthermore, the LED light panel includes a monochrome LED light panel, a dual-color LED light panel, and a full-color LED light panel.

[0022] Furthermore, the external dimming shutdown control circuit is an LED photosensitive control circuit, a damping circuit, an anti-interference circuit, or a detection circuit;

[0023] Among them, the LED photosensitive control circuit adjusts the brightness of the LED light panel by controlling the real-time current of the DC-DC step-down output circuit;

[0024] The damping circuit connects different numbers of RC damping circuits in series through a DC-DC step-down output circuit to consume the residual power of the LED board in the afterglow circuit.

[0025] The anti-interference circuit controls the stability of the LED board by filtering and conditioning the DC-DC step-down output circuit;

[0026] The detection circuit is used to determine whether there is a circuit risk by detecting the remaining power of the LED board in the afterglow circuit when the LED board receives a light-off signal.

[0027] Furthermore, the LED photosensitive control circuit includes: a phototransistor, a color-sensitive optoelectronic device, a photosensitive processing chip, a voltage acquisition unit, and a DSP processor; wherein,

[0028] The base of the phototransistor is connected to the driving power supply through the fourth resistor, the emitter of the phototransistor is grounded, and the collector of the phototransistor is connected to the input terminal of the photosensitive processing chip through the fifth resistor.

[0029] The output terminal of the color-sensitive optoelectronic device is connected to the signal input terminal of the photosensitive processing chip;

[0030] The output of the photosensitive processing chip is connected to the input of the DSP processor;

[0031] The positive input terminal of the voltage acquisition unit is connected to the positive terminal of the LED board through a voltage divider resistor network, the negative input terminal of the voltage acquisition unit is connected to the negative terminal of the LED board, and the output terminal of the voltage acquisition unit is connected to the ADC input or analog input of the DSP processor.

[0032] The PWM output or DAC output of the DSP processor is connected to the control input of the DC-DC buck circuit.

[0033] Furthermore, the damping circuit includes multiple RC damping circuits and a digital controller;

[0034] Each RC damping circuit consists of a resistor R and a capacitor C connected in series.

[0035] Each control port in the digital controller controls a series switch of an RC damping circuit.

[0036] An indicator, connected to the input terminal of the digital controller and in parallel with the LED panel, is used to determine the remaining power. The indicator is also used to send an encoded signal to the digital controller based on the remaining power, and the encoded signal is used to control the number of series switches that are turned on.

[0037] Furthermore, the anti-interference circuit includes: a power supply filter, a decoupling circuit, a bypass capacitor, an opto-isolator, a TVS diode, a main filter and a main amplifier, a temperature sensor, and a microcontroller;

[0038] The microcontroller is used to connect the input terminals of the temperature sensor, power filter, and decoupling circuit.

[0039] The input terminal of the power filter is connected to the output terminal of the DC-DC step-down output circuit;

[0040] The input terminal of the decoupling circuit is connected to the output terminal of the power supply filter, and a critical bypass capacitor is connected between the power supply pin and the ground pin of the decoupling circuit; the bypass capacitor is a ceramic capacitor.

[0041] The optical isolator is connected between the output of the decoupling circuit and the drive power supply;

[0042] TVS diodes are connected in parallel at the input terminals of the optical isolator and the decoupling circuit;

[0043] The input terminal of the main filter is used to connect to the output terminal of the decoupling circuit;

[0044] The main amplifier is connected to the output of the main filter.

[0045] Furthermore, the detection circuit includes, specifically, a trigger circuit, a selection circuit, and an output circuit.

[0046] The output of the trigger circuit is electrically connected to the input of the afterglow removal circuit.

[0047] Trigger circuit: Used to extend the width of the initial command signal. It generates the first command signal by using N cascaded flip-flops, each of which is triggered on the rising edge of the target clock signal.

[0048] Selection circuit: Based on the encoded signal of the mode register, it generates a first selection signal and a second selection signal, which are used to control the effective level length of the target command signal generated by the output circuit;

[0049] Output circuit: including a first output circuit and a second output circuit, used to generate target command signals, the effective level length of which corresponds to the burst length mode.

[0050] Other features and advantages of this application will be set forth in the following description and will be apparent in part from the description or may be learned by practicing the application. The objectives and other advantages of this application may be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings.

[0051] The technical solution of this application will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0052] The accompanying drawings are provided to further illustrate the present application and form part of the specification. They are used together with the embodiments of the present application to explain the application and do not constitute a limitation thereof. In the drawings:

[0053] Figure 1This is a structural diagram of a circuit that enables a non-isolated drive power supply to turn off lights without afterglow, as described in an embodiment of this application.

[0054] Figure 2 This is a circuit diagram illustrating a non-isolated drive power supply circuit that eliminates afterglow when turning off lights, as described in an embodiment of this application.

[0055] Figure 3 This is a circuit diagram of the DC-DC step-down circuit in the embodiments of this application;

[0056] Figure 4 This is a diagram showing the composition of the external dimming off control circuit in an embodiment of this application;

[0057] Figure 5 This is a circuit diagram of the LED photosensitive control circuit in an embodiment of this application.

[0058] Figure 6 This is a circuit diagram of the damping circuit in an embodiment of this application.

[0059] Figure 7 This is a schematic diagram of the anti-interference circuit in the embodiments of this application. Detailed Implementation

[0060] The preferred embodiments of this application are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit this application.

[0061] Example 1:

[0062] This application proposes a circuit for achieving afterglow-free operation when turning off lights using a non-isolated drive power supply, comprising:

[0063] The positive terminal of the drive power supply is electrically connected to the first input terminal of the DC-DC step-down output circuit, and the negative terminal of the drive power supply is electrically connected to one end of the non-persistent circuit.

[0064] The other end of the non-persistent circuit is connected to the second output terminal of the DC-DC step-down output circuit; wherein, the non-persistent circuit includes a thyristor Q5, and the anode of the thyristor Q5 is electrically connected to the second output terminal of the DC-DC step-down output circuit;

[0065] The first output terminal of the DC-DC step-down output circuit is electrically connected to the positive terminal of the LED board, and the negative terminal of the LED board is electrically connected to the second output terminal of the DC-DC step-down output circuit.

[0066] The principle of the above technical solution is as follows: This solution includes the following parts: output DC / DC step-down circuit, LED light board, afterglow control circuit, and dimming shutdown control.

[0067] The afterglow-free circuit and the DC-DC step-down output circuit are also connected to an external dimming shutdown control circuit.

[0068] Example 2:

[0069] As one embodiment of this application, the persistence-free circuit further includes: a first MOSFET Q2, a third transistor Q3, a fourth transistor Q4, a first resistor R1, a second resistor R2, and a third resistor R3; wherein,

[0070] One end of the first resistor R1 is connected to an external dimming and shutdown control circuit, and the other end of the first resistor R1 is electrically connected to the base of the fourth transistor Q4.

[0071] The collector of the fourth transistor Q4 is electrically connected to the gate of the first MOSFET Q2, one end of the second resistor R2, and one end of the third resistor R3. The emitter of the fourth transistor Q4 is connected to the cathode of the thyristor Q5 and the source of the first MOSFET Q2.

[0072] The drain of the first MOSFET Q2 is connected to the control electrode of the thyristor Q5 and the collector of the third transistor Q3, respectively.

[0073] The base of the second transistor Q3 is electrically connected to the other end of the second resistor R2, and the emitter of the third transistor Q3 is electrically connected to the second power supply port VCC2.

[0074] The other end of the third resistor R3 is electrically connected to the first power supply port VCC1.

[0075] In actual implementation, when the drive is normally supplying power to the LED, DIM-CONTROL is at a high level, Q4 (NPN transistor) is turned on, which drives Q3 (PNP transistor) to turn on, while Q2 (MOSFET) is turned off. When Q3 is turned on, VCC1 and VCC2 provide a stable voltage. VCC2 turns on Q5 (SCR) through Q3. When Q5 is turned on, it provides a loop connecting the output LED board to the negative input terminal, maintaining normal output.

[0076] When the driver power supply enters the dimming shutdown stage, the dimming control circuit keeps DIM-CONTROL and VCC2 in a floating state. At this time, Q3 and Q4 are not conducting, while Q2 conducts, pulling the control terminal level of Q5 below 0.2V, completely turning off Q5. Therefore, during the dimming shutdown stage, the non-conducting Q5 disconnects the electrical connection between the output LED- and the input DC-, and simultaneously, the switch between the output LED+ and the input DC+ of the DC / DC step-down circuit is also off. Both the positive and negative terminals of the output are completely disconnected, thus achieving the afterglow-free function.

[0077] Example 3:

[0078] In one embodiment of this application, the driving power supply is a DC power supply.

[0079] Example 4:

[0080] As one embodiment of this application, the DC-DC step-down circuit includes: a first MOSFET Q1, a first diode D1, a fourth resistor R4, a transformer terminal T1-D, a first polarized capacitor CE1, and a second polarized capacitor CE2.

[0081] The drain of the first MOSFET Q1 is connected to the positive terminal DC+ of the power supply and to the negative terminal DC- through the first polarized capacitor CE1. The source of the first MOSFET Q1 is connected to one end of the transformer terminal T1-D through the fourth resistor R4. The other end of the transformer terminal T1-D is electrically connected to the positive terminal of the LED light board.

[0082] The positive terminal of the first diode D1 is connected to the positive terminal of the thyristor Q5 and the negative terminal of the LED board, and the negative terminal of the first diode D1 is connected to the source of the first MOSFET Q1.

[0083] A second polarity resistor CE2 is connected in parallel between the positive and negative terminals of the LED light board.

[0084] Example 5:

[0085] As one embodiment of this application, the LED light panel includes a monochrome LED light panel, a dual-color LED light panel, and a full-color LED light panel.

[0086] In actual implementation, the input voltage is transformed by transformer T1-D to provide appropriate voltage output for various types of LED light boards. Furthermore, all components in the circuit are carefully designed to effectively control current flow, ensuring the circuit's safety and stability.

[0087] Specifically, the DC-DC step-down circuit of this application includes the following main components: a first MOSFET Q1, a first diode D1, a fourth resistor R4, a transformer terminal T1-D, a first polarized capacitor CE1, and a second polarized capacitor CE2. These components together constitute a complete circuit that can meet the voltage requirements of various LED light boards while ensuring safe operation of the circuit.

[0088] First, let's look at the first MOSFET, Q1. Its drain is connected to the positive power supply (DC+), and simultaneously connected to the negative power supply (DC-) through the first polarized capacitor, CE1. This design aims to quickly switch Q1 to a high-impedance state during switching, preventing the power supply voltage from affecting Q1. Furthermore, the source of Q1 is connected to one end of the transformer terminal T1-D through a fourth resistor, R4. This design takes into account the need to ensure voltage stability when the load current changes; therefore, resistor R4 is added to achieve this purpose.

[0089] Next is the first diode, D1, whose anode is connected to the anode of the SCR Q5 and also to the cathode of the LED board. This design allows control of Q5, thereby controlling the switching state of Q1. The cathode of D1 is directly connected to the source of Q1, ensuring circuit continuity.

[0090] Finally, a second polarity resistor CE2 is connected in parallel between the positive and negative terminals of the LED light board. This design makes the LED light board work more stably and also improves the lifespan of the circuit.

[0091] Example 6:

[0092] As one embodiment of this application, such as Figure 4 As shown, the external dimming shutdown control circuit comprises an LED photosensitive control circuit, a damping circuit, an anti-interference circuit, and a detection circuit.

[0093] Among them, the LED photosensitive control circuit adjusts the brightness of the LED light panel by controlling the real-time current of the DC-DC step-down output circuit;

[0094] The damping circuit connects different numbers of RC damping circuits in series through a DC-DC step-down output circuit to consume the residual power of the LED board in the afterglow circuit.

[0095] The anti-interference circuit controls the stability of the LED board by filtering and conditioning the DC-DC step-down output circuit;

[0096] The detection circuit is used to determine whether there is a circuit risk by detecting the remaining power of the LED board in the afterglow circuit when the LED board receives a light-off signal.

[0097] In practical implementation, the external dimming and shutdown control circuit can be connected to various different circuits. Specifically, when connected to the LED photosensitive control circuit, its main task is to precisely adjust the brightness of the LED panel by controlling the circuit current in real time. When connected to the damping circuit, its function is to dissipate the remaining power of the LED panel during the shutdown process by connecting different RC damping circuits in series, thus preventing afterglow. When connected to the anti-interference circuit, it is responsible for filtering the circuit, which can effectively control the stability of the LED panel and prevent brightness instability caused by power supply voltage or frequency fluctuations. When connected to the detection circuit, when the LED panel receives the shutdown signal, it detects the remaining power of the LED panel inside the circuit to determine whether there is a circuit risk, thus ensuring circuit safety.

[0098] Example 7:

[0099] As one embodiment of this application, the LED photosensitive control circuit includes: a phototransistor, a color-sensitive optoelectronic device, a photosensitive processing chip, a voltage acquisition unit, and a DSP processor; wherein,

[0100] The base of the phototransistor is connected to the driving power supply through the fourth resistor R4, the emitter of the phototransistor is grounded, and the collector of the phototransistor is connected to the input terminal of the photosensitive processing chip through the fifth resistor R5.

[0101] The output terminal of the color-sensitive optoelectronic device is connected to the signal input terminal of the photosensitive processing chip;

[0102] The output of the photosensitive processing chip is connected to the input of the DSP processor;

[0103] The positive input terminal of the voltage acquisition unit is connected to the positive terminal of the LED board through a voltage divider resistor network, the negative input terminal of the voltage acquisition unit is connected to the negative terminal of the LED board, and the output terminal of the voltage acquisition unit is connected to the ADC input or analog input of the DSP processor.

[0104] The PWM output or DAC output of the DSP processor is connected to the control input of the DC-DC buck circuit.

[0105] like Figure 5 As shown, in actual implementation, the LED photosensitive control circuit is the core of the entire circuit. Through components such as phototransistors, color-sensitive optoelectronic devices, and photosensitive processing chips, it achieves precise control of the current in the circuit, thereby accurately adjusting the brightness of the LED light panel.

[0106] The base of the phototransistor is connected to the driving power supply, the emitter is grounded, and the collector is connected to the input terminal of the photosensitive processing chip. This ensures the stability of the circuit.

[0107] The output of the color-sensitive optoelectronic device is connected to the signal input of the photosensitive processing chip, and the output of the photosensitive processing chip is connected to the input of the DSP processor. This enables signal processing and analysis.

[0108] The positive input terminal of the voltage acquisition unit is connected to the positive terminal of the LED panel, and the negative input terminal is connected to the negative terminal of the LED panel, thus obtaining accurate voltage information. The output terminal of the voltage acquisition unit is connected to the ADC input or analog input of the DSP processor, allowing for more precise voltage control.

[0109] Finally, the PWM output or DAC output of the DSP processor is connected to the control input of the DC-DC buck circuit. This allows for precise voltage control via the DSP processor, achieving the goal of eliminating afterglow when the non-isolated drive power supply is turned off.

[0110] Example 8:

[0111] As one embodiment of this application, see [link to relevant documentation]. Figure 6 The damping circuit includes multiple RC damping circuits and a digital controller;

[0112] Each RC damping circuit consists of a resistor R and a capacitor C connected in series.

[0113] Each control port in the digital controller controls a series switch of an RC damping circuit.

[0114] An indicator, connected to the input terminal of the digital controller and in parallel with the LED panel, is used to determine the remaining power. The indicator is also used to send an encoded signal to the digital controller based on the remaining power, and the encoded signal is used to control the number of series switches that are turned on.

[0115] like Figure 5 As shown, in actual implementation, the damping circuit's function is to reduce voltage fluctuations caused by battery self-discharge, ensuring the stability of the LED light board's operation. By connecting multiple RC damping circuits in series, voltage fluctuations can be effectively eliminated, improving power utilization. The digital controller can then precisely control the circuit's operating state by controlling the number of series switches that are on. Each control port corresponds to one RC damping circuit, enabling refined management of the entire circuit. Furthermore, the indicator plays a crucial role. It displays the remaining battery power in real time, allowing operators to understand the battery's status promptly and avoid equipment damage due to misoperation. Simultaneously, the indicator can also send corresponding coded signals to the digital controller based on the remaining battery power to control the number of series switches on, further optimizing the circuit's operating state.

[0116] Example 8:

[0117] As one embodiment of this application, see [link to relevant documentation]. Figure 7 The anti-interference circuit includes: a power supply filter, a decoupling circuit, a bypass capacitor, an opto-isolator, a TVS diode, a main filter and a main amplifier, a temperature sensor, and a microcontroller;

[0118] The microcontroller is used to connect the input terminals of the temperature sensor, power filter, and decoupling circuit.

[0119] The input terminal of the power filter is connected to the output terminal of the DC-DC step-down output circuit;

[0120] The input terminal of the decoupling circuit is connected to the output terminal of the power supply filter. The power supply pin and the ground pin of the decoupling circuit are critical bypass capacitors; the bypass capacitor is a ceramic capacitor.

[0121] The optical isolator is connected between the output of the decoupling circuit and the drive power supply;

[0122] TVS diodes are connected in parallel at the input terminals of the optical isolator and the decoupling circuit;

[0123] The input terminal of the main filter is used to connect to the output terminal of the decoupling circuit;

[0124] The main amplifier is connected to the output of the main filter.

[0125] like Figure 7 As shown in the actual implementation, the advantages of various electronic components, such as opto-isolators, TVS diodes, main filters, and main amplifiers, are fully utilized to achieve functions such as power filtering, decoupling, and protection. The opto-isolator disconnects the DC power supply between the input and output terminals, providing excellent anti-interference and protecting the drive power supply from external electromagnetic fields. TVS diodes are mainly used to protect the circuit from overvoltage damage, capable of rapid response and carrying large amounts of energy, preventing damage to other components due to overvoltage. The main filter and main amplifier are responsible for converting the output of the decoupling circuit into a waveform suitable for the drive power supply, ensuring normal circuit operation. Additionally, temperature sensors help monitor the operating temperature of the power filter and main filter, allowing for timely heat dissipation measures or component replacement to ensure the circuit operates in an optimal environment. Finally, the microcontroller, as the central controller of the entire system, coordinates and controls all functional modules, enabling the entire power system to work collaboratively and achieve maximum efficiency.

[0126] Example 9:

[0127] As one embodiment of this application, the detection circuit includes: a trigger circuit, a selection circuit, and an output circuit.

[0128] The output of the trigger circuit is electrically connected to the input of the afterglow removal circuit.

[0129] Trigger circuit: Used to extend the width of the initial command signal. It generates the first command signal by using N cascaded flip-flops, each of which is triggered on the rising edge of the target clock signal.

[0130] Selection circuit: Based on the encoded signal of the mode register, it generates a first selection signal and a second selection signal, which are used to control the effective level length of the target command signal generated by the output circuit;

[0131] Output circuit: including a first output circuit and a second output circuit, used to generate target command signals, the effective level length of which corresponds to the burst length mode.

[0132] In practical implementation, the solution for achieving a non-isolated driver power supply-based LED shut-off circuit with no afterglow also incorporates a flexible and precise detection circuit. This detection circuit mainly consists of three parts: a trigger circuit, a selection circuit, and an output circuit. The trigger circuit's task is to extend the width of the initial command signal to more accurately control the LED's state. It achieves this through N cascaded flip-flops, each triggered on the rising edge of the target clock signal, thus generating a series of command signals. This allows for finer control of the LED's state, resulting in a better shut-off effect. The selection circuit generates two sets of selection signals based on the encoding signal in the mode register: a first selection signal and a second selection signal. These two sets of signals are used to control the effective level length of the target command signal generated by the output circuit. This allows us to adjust the command signal length according to different modes to achieve the optimal shut-off effect. The output circuit mainly consists of two parts: a first output circuit and a second output circuit. The main task of these two parts is to generate the target command signal, whose effective level length matches the burst length mode. Thus, by controlling the operation of these two circuits, a target command signal that meets expectations and achieves a good shut-off effect can be generated. In summary, this implementation scheme, by introducing a detection circuit, enables us to control the state of the LEDs more precisely and meticulously, thereby achieving the desired light-off effect and improving the overall circuit performance.

[0133] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A circuit for achieving afterglow-free operation when turning off lights using a non-isolated drive power supply, characterized in that, include: The positive terminal of the drive power supply is electrically connected to the first input terminal of the DC-DC step-down output circuit, and the negative terminal of the drive power supply is electrically connected to one end of the non-persistent circuit. The other end of the non-persistent circuit is electrically connected to the second output terminal of the DC-DC step-down output circuit; wherein, the non-persistent circuit includes a thyristor Q5, and the anode of the thyristor Q5 is electrically connected to the second output terminal of the DC-DC step-down output circuit; The first output terminal of the DC-DC step-down output circuit is electrically connected to the positive terminal of the LED board, and the negative terminal of the LED board is electrically connected to the second output terminal of the DC-DC step-down output circuit. The afterglow-free circuit and the DC-DC step-down output circuit are also connected to an external dimming shutdown control circuit.

2. The circuit for achieving afterglow-free operation when turning off lights using a non-isolated drive power supply as described in claim 1, characterized in that, The afterglow-free circuit further includes: a second MOSFET Q2, a third transistor Q3, a fourth transistor Q4, a first resistor R1, a second resistor R2, and a third resistor R3; wherein, One end of the first resistor R1 is connected to an external dimming and shutdown control circuit, and the other end of the first resistor R1 is electrically connected to the base of the fourth transistor Q4. The collector of the fourth transistor Q4 is electrically connected to the gate of the second MOSFET Q2, one end of the second resistor R2, and one end of the third resistor R3. The emitter of the fourth transistor Q4 is connected to the cathode of the thyristor Q5 and the source of the second MOSFET Q2. The drain of the second MOSFET Q2 is connected to the control electrode of the thyristor Q5 and the collector of the third transistor Q3, respectively. The base of the third transistor Q3 is electrically connected to the other end of the second resistor R2, and the emitter of the third transistor Q3 is electrically connected to the second power supply port VCC2. The other end of the third resistor R3 is electrically connected to the first power supply port VCC1.

3. The circuit for achieving afterglow-free operation when turning off lights using a non-isolated drive power supply as described in claim 1, characterized in that, The driving power supply is a DC power supply.

4. The circuit for achieving afterglow-free operation when turning off lights using a non-isolated drive power supply as described in claim 1, characterized in that, The DC-DC step-down circuit includes: a first MOSFET Q1, a first diode D1, a fourth resistor R4, a transformer terminal T1-D, a first polarized capacitor CE1, and a second polarized capacitor CE2. The drain of the first MOSFET Q1 is connected to the positive terminal DC+ of the power supply and to the negative terminal DC- through the first polarized capacitor CE1. The source of the first MOSFET Q1 is connected to one end of the transformer terminal T1-D through the fourth resistor R4. The other end of the transformer terminal T1-D is electrically connected to the positive terminal of the LED light board. The positive terminal of the first diode D1 is connected to the positive terminal of the thyristor Q5 and the negative terminal of the LED board, and the negative terminal of the first diode D1 is connected to the source of the first MOSFET Q1. A second polarity resistor CE2 is connected in parallel between the positive and negative terminals of the LED light board.

5. A circuit for achieving afterglow-free operation when turning off lights using a non-isolated drive power supply as described in claim 1, characterized in that, The LED light panels include monochrome LED light panels, dual-color LED light panels, and full-color LED light panels.

6. A circuit for achieving afterglow-free operation when turning off lights using a non-isolated drive power supply as described in claim 1, characterized in that, The external dimming shutdown control circuit consists of an LED photosensitive control circuit, a damping circuit, an anti-interference circuit, and a detection circuit. The LED photosensitive control circuit is electrically connected to the control terminal of the DC-DC step-down output circuit. The damping circuit is electrically connected to the output terminal of the DC-DC step-down output circuit and the input terminal of the LED light board; The anti-interference circuit is electrically connected to the output terminal of the DC-DC step-down output circuit and to the output terminal of the damping circuit. The detection circuit is electrically connected to the LED light board.

7. A circuit for achieving afterglow-free operation when turning off lights using a non-isolated drive power supply as described in claim 6, characterized in that, The LED photosensitive control circuit includes: a phototransistor, a color-sensitive optoelectronic device, a photosensitive processing chip, a voltage acquisition unit, and a DSP processor; wherein... The base of the phototransistor is connected to the driving power supply through the fourth resistor R4, the emitter of the phototransistor is grounded, and the collector of the phototransistor is connected to the input terminal of the photosensitive processing chip through the fifth resistor R5. The output terminal of the color-sensitive optoelectronic device is connected to the signal input terminal of the photosensitive processing chip; The output of the photosensitive processing chip is connected to the input of the DSP processor; The positive input terminal of the voltage acquisition unit is connected to the positive terminal of the LED board through a voltage divider resistor network, the negative input terminal of the voltage acquisition unit is connected to the negative terminal of the LED board, and the output terminal of the voltage acquisition unit is connected to the ADC input or analog input of the DSP processor. The PWM output or DAC output of the DSP processor is connected to the control input of the DC-DC buck circuit.

8. A circuit for achieving afterglow-free operation when turning off lights using a non-isolated drive power supply as described in claim 6, characterized in that, The damping circuit includes multiple RC damping circuits and a digital controller; Each RC damping circuit consists of a resistor R and a capacitor C connected in series. Each control port in the digital controller controls a series switch of an RC damping circuit. An indicator is connected to the input of the digital controller and in parallel with the LED light panel.

9. A circuit for achieving afterglow-free operation when turning off lights using a non-isolated drive power supply as described in claim 6, characterized in that, The anti-interference circuit includes: a power supply filter, a decoupling circuit, a bypass capacitor, an opto-isolator, a TVS diode, a main filter and a main amplifier, a temperature sensor, and a microcontroller; The microcontroller is used to connect the input terminals of the temperature sensor, power filter, and decoupling circuit. The input terminal of the power filter is connected to the output terminal of the DC-DC step-down output circuit; The input terminal of the decoupling circuit is connected to the output terminal of the power supply filter. The power supply pin and the ground pin of the decoupling circuit are adjacent bypass capacitors; the bypass capacitors are ceramic capacitors. The optical isolator is connected between the output of the decoupling circuit and the drive power supply; TVS diodes are connected in parallel at the input terminals of the optical isolator and the decoupling circuit; The input terminal of the main filter is used to connect to the output terminal of the decoupling circuit; The main amplifier is connected to the output of the main filter.

10. A circuit for achieving afterglow-free operation when turning off lights using a non-isolated drive power supply as described in claim 6, characterized in that, The output terminal of the detection circuit is electrically connected to the input terminal of the afterglow removal circuit.

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