Afterglow eliminating circuit

Abstract

The invention relates to the technical field of driving power supplies, and discloses an afterglow elimination circuit which comprises an afterglow turn-off circuit, the output end of the afterglow turn-off circuit is connected with an output circuit, the input end of the afterglow turn-off circuit is connected with a step-down circuit and a power supply circuit, the power supply circuit is connected with a control circuit, and the step-down circuit is connected with a dimming circuit and a booster circuit. According to the technical scheme, the control circuit is connected with the afterglow turn-off circuit to control turn-off of afterglow, during normal work, after the control circuit provides a high level, the LED lamp panel is normally lightened, and the dimming control circuit sends out a dimming turn-off instruction, the control circuit provides a low level, so that the circuit is turned off, and leakage current cannot flow through the circuit; meanwhile, through the two diodes and the MOS tube which are connected with the step-down circuit, full blocking of leakage current is achieved, cost is low, reliability is achieved, and the LED dimming circuit is suitable for I-type lamps.

Description

Technical Field

[0001] The invention relates to the technical field of driving power supplies, and in particular to an afterglow elimination circuit. Background Art

[0002] In recent years, the application of smart lighting fixtures in the lighting market has become more and more extensive, and its market share is constantly increasing. In the application of non-isolated dimming drivers, for the sake of safety voltage, floating output solutions are often used to prevent the LED light board from having excessive voltage. The application of smart dimmers allows the switch of the light to be controlled through the control circuit. Usually in this case, the live wire is connected, and the high voltage of the live wire will be transmitted to the LED light board through the distributed capacitor, causing micro-ampere leakage current to flow through the LED light board. In this case, the lamp will be slightly bright, especially in the dark, with afterglow, which is also what we often call the ghost fire phenomenon. In response to this phenomenon, the elimination of ghost fire can greatly improve the user experience. At present, the afterglow elimination function is gradually integrated into the LED driver power supply.

[0003] The Chinese patent document with the publication number CN117641660A discloses a "afterglow removal circuit, PCB board and driving power supply". The afterglow removal circuit includes an input boost unit, an output buck unit, a dimming unit, an auxiliary power supply unit and a switch unit. The input boost unit is connected to the input end of the output buck unit through the switch unit, and the output end of the input boost unit is respectively connected to the light supply end of the dimming unit, the input end of the auxiliary power supply unit and the power supply end of the switch unit; the output end of the dimming unit is connected to the sensing end of the auxiliary power supply unit, and the output end of the auxiliary power supply unit is respectively connected to the power supply end of the input boost unit and the power supply end of the output buck unit, and the trigger end of the auxiliary power supply unit is connected to the sensing end of the switch unit. The above technical solution cannot achieve full blocking of the corresponding leakage current. Summary of the invention

[0004] The present invention mainly solves the technical problem that the original technical solution cannot achieve full blocking of the corresponding leakage current, and provides an afterglow elimination circuit, which is connected to the afterglow shutdown circuit through a control circuit to control the shutdown of the afterglow. During normal operation, the control circuit provides a high level, and the LED lamp panel is normally lit. After the dimming control circuit sends a dimming off instruction, the control circuit provides a low level to achieve circuit shutdown, and the leakage current cannot flow through this circuit. The afterglow is effectively eliminated when the dimming is turned off. At the same time, through two diodes and a MOS tube connected to the step-down circuit, the leakage current is fully blocked. The circuit is low-cost and reliable, and is suitable for Class I lamps.

[0005] The above technical problems of the present invention are mainly solved by the following technical solutions: the present invention includes an afterglow shutdown circuit, the output end of the afterglow shutdown circuit is connected to the output circuit, the input end is respectively connected to the step-down circuit and the power supply circuit, the power supply circuit is connected to the control circuit, the step-down circuit is respectively connected to the dimming circuit and the boost circuit, the afterglow shutdown circuit includes a MOS tube Q1 connected to the output end of the step-down circuit, a transistor Q2 connected to the output end of the power supply circuit, and a transistor Q3 connected to the output end of the control circuit.

[0006] Preferably, the source of the MOS transistor Q1 is connected to the output end of the step-down circuit, the drain is connected to the output circuit via the cathode of the diode D2, and the gate is connected to the emitter of the transistor Q2.

[0007] Preferably, the collector of the transistor Q2 is connected to the output end of the power supply circuit, and the output end of the power supply circuit is connected to the power supply end. At the same time, the output end of the power supply circuit is connected to the base of the transistor Q2 through the resistor R2.

[0008] Preferably, the base of the transistor Q2 is connected to the emitter of the transistor Q3 via a resistor R3, the collector of the transistor Q3 is grounded, the base of the transistor Q3 is connected to the control circuit via a resistor R4, and the base of the transistor Q3 is grounded via a resistor R5.

[0009] Preferably, one end of the output end of the step-down circuit is connected to the output circuit via the positive electrode of the diode D1, and the other end of the output end of the step-down circuit is grounded via the capacitor CY1.

[0010] Preferably, a chip US2 is further included, the model of chip US2 is BP2879D, the pin 1 of the chip US2 is connected to the source of the MOS tube QS3 through the capacitor CS13, the gate of the MOS tube QS3 is connected to the emitter of the triode US6A, the collector of the triode US6A is connected to the power supply end through the resistor RS45 and the resistor RS44 in sequence, and the drain of the MOS tube QS3 is connected to the power supply end through the resistor RS42.

[0011] Preferably, pin 2 of the chip US2 is grounded through resistor RS58 and connected to one end of inductor T3B. The other end of inductor T3B is connected to the power supply end through diode DS14 and resistor RS51 in sequence. At the same time, pin 2 is connected to the source of MOS tube QS3 through resistor RS58.

[0012] Preferably, pin 4 of the chip US2 is connected to the source of MOS tube QS3 through a parallel resistor RS50 and a capacitor CS9, pin 7 is connected to MOS tube Q2 through a resistor RS28 and a cathode of a diode DS10, and pin 7 is connected to MOS tube Q2 through a resistor RS29.

[0013] Preferably, pin 6 of the chip US2 is connected to the source of the MOS tube QS3 through capacitor CS14, pin 6 is connected to the gate of the MOS tube Q2 through resistor RS30, the source of the MOS tube Q2 is grounded through parallel resistors RS32, RS33, RS34 and RS40, and the drain of the OS tube Q2 is connected to the power supply terminal.

[0014] Preferably, the pin 8 of the chip US2 is connected to the source of the MOS tube QS3 through the capacitor EC3 and the capacitor CS16 connected in parallel, and the pin 8 is connected to the power supply terminal and to the pin 2 through the resistor RS57.

[0015] The beneficial effects of the present invention are as follows: by connecting the control circuit with the afterglow shutdown circuit to control the shutdown of the afterglow, during normal operation, the control circuit provides a high level, and the LED lamp panel lights up normally. After the dimming control circuit sends a dimming off instruction, the control circuit provides a low level to realize circuit shutdown, and the leakage current cannot flow through this circuit. The afterglow is effectively eliminated when the dimming is turned off. At the same time, through two diodes and a MOS tube connected to the step-down circuit, the leakage current is fully blocked. It is low-cost and reliable, and is suitable for Class I lamps. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a circuit principle connection structure diagram of the present invention.

[0017] Figure 2 The invention discloses an afterglow shutdown circuit diagram.

[0018] Figure 3 The invention discloses an afterglow shutdown control circuit diagram.

[0019] Figure 4 The invention discloses an afterglow shutdown auxiliary circuit diagram.

[0020] Figure 5 It is another afterglow shutdown auxiliary circuit diagram of the present invention. DETAILED DESCRIPTION

[0021] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the technical solutions of the present application are further described in detail below through embodiments and in combination with the accompanying drawings. It should be understood that the specific implementation method described here is only an optimal embodiment of the present application, which is only used to explain the present application and does not limit the protection scope of the present application. All other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0022] The technical solution of the present invention is further specifically described below through embodiments and in conjunction with the accompanying drawings.

[0023] Embodiment: A afterglow elimination circuit of this embodiment, such as Figure 1 As shown, it includes an afterglow shutdown circuit, the output end of the afterglow shutdown circuit is connected to the output circuit, the input end is respectively connected to the step-down circuit and the power supply circuit, the power supply circuit is connected to the control circuit, the step-down circuit is respectively connected to the dimming circuit and the boost circuit, and the afterglow shutdown circuit includes a MOS tube Q1 connected to the output end of the step-down circuit, a transistor Q2 connected to the output end of the power supply circuit, and a transistor Q3 connected to the output end of the control circuit. The source of the MOS tube Q1 is connected to the output end of the step-down circuit, the drain is connected to the output circuit through the negative electrode of the diode D2, and the gate is connected to the emitter of the transistor Q2. The collector of the transistor Q2 is connected to the output end of the power supply circuit, and the output end of the power supply circuit is connected to the power supply end, and the output end of the power supply circuit is connected to the base of the transistor Q2 through the resistor R2. The base of transistor Q2 is connected to the emitter of transistor Q3 through resistor R3, the collector of transistor Q3 is grounded, the base of transistor Q3 is connected to the control circuit through resistor R4, and the base of transistor Q3 is grounded through resistor R5. One end of the output end of the step-down circuit is connected to the output circuit through the positive electrode of diode D1, and the other end of the output end of the step-down circuit is grounded through capacitor CY1.

[0024] like Figure 2 , Figure 3 , Figure 4 , Figure 5As shown, the afterglow elimination circuit also includes a chip US2, the model of the chip US2 is BP2879D, the pin 1 of the chip US2 is connected to the source of the MOS tube QS3 through the capacitor CS13, the gate of the MOS tube QS3 is connected to the emitter of the three-stage tube US6A, the collector of the three-stage tube US6A is connected to the power supply end through the resistor RS45 and the resistor RS44 in turn, and the drain of the MOS tube QS3 is connected to the power supply end through the resistor RS42. The pin 2 of the chip US2 is connected to one end of the inductor T3B while being grounded through the resistor RS58, and the other end of the inductor T3B is connected to the power supply end through the diode DS14 and the resistor RS51 in turn, and the pin 2 is connected to the source of the MOS tube QS3 through the resistor RS58. The pin 3 of the chip US2 is connected to the FB end. The pin 4 of the chip US2 is connected to the source of the MOS tube QS3 through the parallel resistor RS50 and the capacitor CS9. The pin 5 of the chip US2 is connected to the GND end. Pin 6 of chip US2 is connected to the source of MOS tube QS3 through capacitor CS14, and pin 6 is connected to the gate of MOS tube Q2 through resistor RS30. The source of MOS tube Q2 is grounded through resistor RS32, resistor RS33, resistor RS34, and resistor RS40 connected in parallel, and the drain of OS tube Q2 is connected to the power supply end. Pin 7 is connected to MOS tube Q2 through resistor RS28 and the cathode of diode DS10, and pin 7 is connected to MOS tube Q2 through resistor RS29. Pin 8 of chip US2 is connected to the source of MOS tube QS3 through capacitor EC3 and capacitor CS16 connected in parallel, and pin 8 is connected to the power supply end and pin 2 through resistor RS57.

[0025] Embodiment 2: like Figure 1 As shown, the afterglow elimination circuit of this embodiment includes a boost circuit, a buck circuit, a dimming control circuit, a power supply circuit and an afterglow shutoff circuit. The boost circuit, the buck circuit connected to the output end of the boost circuit, the dimming control circuit and the power supply circuit connected to the two ends of the buck circuit, the power supply circuit and the control circuit connected, the buck circuit, the power supply circuit, the control circuit connected to the afterglow shutoff circuit, and the afterglow shutoff circuit connected to the output circuit-LED load. The input end of the boost circuit receives the input voltage Vin, and the output end outputs the boosted voltage Vout. The input end of the buck circuit is connected to the output end of the boost circuit, and the output end outputs the stepped-down voltage Vled, which is used to drive the output circuit LED load 7. The input end of the dimming control circuit receives the dimming signal Dim, and the output end is connected to the control end of the boost circuit, which is used to adjust the output voltage of the boost circuit according to the dimming signal. The power supply circuit provides a stable power supply Vcc for the entire circuit. The input end of the afterglow shutoff circuit is connected to the output end of the step-down circuit, and the output end is connected to the output circuit, so as to quickly eliminate the afterglow after the output circuit is turned off.

[0026] Specifically, the afterglow shutdown circuit includes a diode D1, a MOS tube Q1, a resistor R1, a Y1 capacitor CY1 and a diode D2. The anode of the diode D1 is connected to the first end of the step-down circuit (i.e., the positive output end), and the cathode is connected to the output circuit (i.e., the input end of the LED load). The drain of the MOS tube Q1 is connected to the first end of the resistor R1, and the source is connected to the cathode of the diode D2. The second end of the resistor R1 is connected to the gate of the MOS tube Q1 and the collector of the transistor Q2. The first end of the Y1 capacitor CY1 is connected to the first end of the resistor R1, and the second end is connected to the ground signal GND. The anode of the diode D2 is connected to the output circuit, and the cathode is connected to the source of the MOS tube Q1. The power supply circuit includes a transistor Q2, a resistor R2 and a resistor R3. The first end of the resistor R2 and the first end of the resistor R3 are respectively connected to the base of the transistor Q2. The emitter of the transistor Q2 is respectively connected to the second end of the resistor R2 and the power supply circuit (i.e., Vcc). The second end of the resistor R3 is connected to the emitter of the transistor Q3.

[0027] The boost circuit is the basic part of the afterglow elimination circuit, which is used to boost the input voltage to meet the working requirements of the subsequent circuit. The specific implementation method of the boost circuit can be selected according to actual needs, such as using a DC-DC boost module. The boost circuit receives the input voltage and boosts it to provide a stable voltage output. The specific structure and parameters of the boost circuit can be designed according to actual needs. The buck circuit is connected to the output end of the boost circuit to reduce the boosted voltage to a voltage range suitable for the operation of the LED load. The specific parameters and component selection of the buck circuit also need to be determined according to the characteristics and requirements of the LED load.

[0028] The dimming control circuit is used to receive the dimming signal and adjust the brightness of the LED load according to the dimming signal. The dimming control circuit may include components such as a potentiometer and a PWM signal generator to achieve accurate brightness adjustment. The power supply circuit is connected to the control circuit to provide the required power supply for the control circuit. In this embodiment, the power supply circuit includes a transistor Q2, a resistor R2 and a resistor R3. The first ends of the resistor R2 and the resistor R3 are respectively connected to the base of the transistor Q2, and the emitter of the transistor Q2 is connected to the second end of the resistor R2 and the power supply circuit to provide a stable power supply for the control circuit.

[0029] The control circuit includes a transistor Q3, a resistor R4 and a resistor R5. The first end of the resistor R4 is connected to the control circuit (i.e., the external control signal input end). The second end of the resistor R4 and the first end of the resistor R5 are respectively connected to the base of the transistor Q3. The collector of the transistor Q3 is connected to the second end of the resistor R5 and the signal ground GND. When the afterglow of the LED load needs to be turned off, the control circuit sends a shutdown signal to the MOS tube Q1. The external control signal turns off the transistor Q3 through the control circuit, thereby disconnecting the gate control signal of the MOS tube Q1. After receiving the shutdown signal, the MOS tube Q1 is quickly turned off, thereby cutting off the power supply circuit of the LED load and realizing the rapid elimination of the afterglow. At the same time, the Y1 capacitor CY1 plays the role of filtering and stabilizing the voltage in the circuit, which helps to reduce the impact of voltage fluctuations on the LED load. Diodes D1 and D2 play the role of protecting the circuit to prevent the reverse flow of current from damaging the circuit.

[0030] Embodiment 3: like Figure 1 As shown, the afterglow elimination circuit of this embodiment includes a boost circuit, a buck circuit, a dimming control circuit, a power supply circuit and an afterglow shutoff circuit. The boost circuit, the buck circuit connected to the output end of the boost circuit, the dimming control circuit and the power supply circuit connected to the two ends of the buck circuit, the power supply circuit and the control circuit connected, the buck circuit, the power supply circuit, the control circuit and the afterglow shutoff circuit connected, and the afterglow shutoff circuit connected to the output circuit. The input end of the boost circuit receives the input voltage Vin, and the output end outputs the boosted voltage Vout. The input end of the buck circuit is connected to the output end of the boost circuit, and the output end outputs the stepped-down voltage Vled, which is used to drive the output circuit LED load 7. The input end of the dimming control circuit receives the dimming signal Dim, and the output end is connected to the control end of the boost circuit, which is used to adjust the output voltage of the boost circuit according to the dimming signal. The power supply circuit provides a stable power supply Vcc for the entire circuit. The input end of the afterglow shutoff circuit is connected to the output end of the step-down circuit, and the output end is connected to the output circuit LED load 7, so as to quickly eliminate the afterglow after the LED load 6 is turned off.

[0031] The boost circuit is the basic part of the afterglow elimination circuit, which is used to boost the input voltage to meet the working requirements of the subsequent circuit. The specific implementation method of the boost circuit can be selected according to actual needs, such as using a DC-DC boost module. The boost circuit receives the input voltage and boosts it to provide a stable voltage output. The specific structure and parameters of the boost circuit can be designed according to actual needs. The buck circuit is connected to the output end of the boost circuit to reduce the boosted voltage to a voltage range suitable for the LED load. The specific parameters and component selection of the buck circuit also need to be determined according to the characteristics and requirements of the LED load.

[0032] The dimming control circuit is used to receive the dimming signal and adjust the brightness of the LED load according to the dimming signal. The dimming control circuit may include components such as a potentiometer and a PWM signal generator to achieve accurate brightness adjustment. The power supply circuit is connected to the control circuit to provide the required power supply for the control circuit. In this embodiment, the power supply circuit includes a transistor Q2, a resistor R2 and a resistor R3. The first ends of the resistor R2 and the resistor R3 are respectively connected to the base of the transistor Q2, and the emitter of the transistor Q2 is connected to the second end of the resistor R2 and the power supply circuit to provide a stable power supply for the control circuit.

[0033] The control circuit is connected to the step-down circuit, the power supply circuit and the afterglow shut-off circuit, and is used to control the shut-off of the afterglow. In the present embodiment, the control circuit includes a transistor Q3, a resistor R4 and a resistor R5. The emitter of the transistor Q3 is connected to the second end of the resistor R3, and the collector is connected to the second end of the resistor R5 and the signal ground. The base of the transistor Q3 is connected to the control circuit through the resistor R5 and the resistor R4, and receives a control signal to control the shut-off of the afterglow. The power supply circuit includes a transistor Q2', a resistor R2', a resistor R3' and a voltage regulator diode D3. The first end of the resistor R2' and the first end of the resistor R3' are respectively connected to the base of the transistor Q2'. The emitter of the transistor Q2' is respectively connected to the second end of the resistor R2' and the power supply circuit (i.e., Vcc'). The second end of the resistor R3' is connected to the cathode of the voltage regulator diode D3, and the anode of the voltage regulator diode D3 is connected to the signal ground GND. The voltage regulator diode D3 is used to provide a stable power supply voltage Vcc' for the power supply circuit. The structure of the control circuit is the same as that of the first embodiment, but the source of the control signal may be different. In this embodiment, the control signal may come from an external controller (such as MCU) or other signal sources.

[0034] The afterglow shutdown circuit is used to quickly eliminate the afterglow phenomenon after the LED load is turned off. The afterglow shutdown circuit includes a diode D1, a MOS tube Q1, a resistor R1, a Y1 capacitor CY1 and a diode D2. The anode of the diode D1 is connected to the first end of the step-down circuit, and the cathode is connected to the output circuit. The anode of the diode D2 is connected to the output circuit, and the cathode is connected to the source of the MOS tube Q1. The gate of the MOS tube Q1 is connected to the second end of the resistor R1 and the collector of the transistor Q2, and is used to receive a control signal to control the switching state of the MOS tube. The first end of the resistor R1 is connected to the drain of the MOS tube Q1 and the first end of the Y1 capacitor CY1, and the second end of the Y1 capacitor CY1 is connected to the ground signal, which is used to stabilize the circuit operation.

[0035] When the afterglow of the LED load needs to be eliminated, the control circuit sends a control signal to control the switch state of the MOS tube Q1 through components such as the triode Q3. When the MOS tube Q1 is turned off, the power supply circuit of the LED load is cut off, thereby quickly eliminating the afterglow phenomenon. At the same time, components such as the Y1 capacitor CY1 can absorb and release charges, further stabilizing the circuit operation and improving the effect of eliminating the afterglow.

[0036] Embodiment 4: like Figure 1 As shown, the afterglow elimination circuit of this embodiment includes a boost circuit, a buck circuit, a dimming control circuit, a power supply circuit and an afterglow shutoff circuit. The boost circuit, the buck circuit connected to the output end of the boost circuit, the dimming control circuit and the power supply circuit connected to the two ends of the buck circuit, the power supply circuit and the control circuit connected, the buck circuit, the power supply circuit, the control circuit connected to the afterglow shutoff circuit, and the afterglow shutoff circuit connected to the output circuit LED load 7. The input end of the boost circuit receives the input voltage Vin, and the output end outputs the boosted voltage Vout. The input end of the buck circuit is connected to the output end of the boost circuit, and the output end outputs the stepped-down voltage Vled, which is used to drive the output circuit LED load 7. The input end of the dimming control circuit receives the dimming signal Dim, and the output end is connected to the control end of the boost circuit, which is used to adjust the output voltage of the boost circuit according to the dimming signal. The power supply circuit provides a stable power supply Vcc for the entire circuit. The input end of the afterglow shutoff circuit is connected to the output end of the step-down circuit, and the output end is connected to the output circuit LED load 7, so as to quickly eliminate the afterglow after the LED load 6 is turned off.

[0037] Specifically, the afterglow shutdown circuit includes a diode D1 connected to the first end of the step-down circuit, a MOS tube Q1, a resistor R1 and a Y1 capacitor CY1 connected to the second end of the step-down circuit, and a diode D2 connected to the MOS tube Q1. The anode of the diode D1 is connected to the first end of the step-down circuit, the cathode of the diode D1 is connected to the output circuit, and the anode of the diode D2 is connected to the output circuit; the cathode of the diode D2 is connected to the source of the MOS tube Q1, the gate of the MOS tube Q1 is connected to the second end of the resistor R1 and the collector of the transistor Q2, and the first end of the resistor R1 is connected to the drain of the MOS tube Q1 and the first end of the Y1 capacitor CY1 respectively. The signals of the first end of the resistor R1 and the MOS tube Q1 are transmitted to the MCU, and the second end of the Y1 capacitor CY1 is connected to the ground signal. The power supply circuit includes a transistor Q2 connected to the second end of the resistor R1, a resistor R2 and a resistor R3 connected to the transistor Q2; wherein the first end of the resistor R2 and the first end of the resistor R3 are respectively connected to the base of the transistor Q2, and the emitter of the transistor Q2 is respectively connected to the second end of R2 and the power supply circuit. The emitter of the transistor Q2 provides a power supply circuit for the switch of the MOS transistor Q1, and the control circuit includes a transistor Q3 connected to the resistor R3, a resistor R4 connected to the control circuit and the transistor Q3 respectively, and a resistor R5 connected to the resistor R4 and the transistor Q3. The emitter of the transistor Q3 is connected to the second end of the resistor R3, the collector of the transistor Q3 is respectively connected to the second end of the resistor R5 and the signal ground, the base of the transistor Q3 is respectively connected to the first end of the resistor R5 and the second end of the resistor R4, and the first end of the resistor R4 is connected to the control circuit. The input end of the dimming control circuit is used to obtain a dimming signal, and the boost circuit is used to boost the input voltage. The boost circuit receives the input voltage and performs a boost process on it to provide a stable voltage output. The specific structure and parameters of the boost circuit can be designed according to actual needs. The buck circuit is connected to the output end of the boost circuit and is used to reduce the boosted voltage to a voltage range suitable for the operation of the LED load. The specific parameters and component selection of the buck circuit also need to be determined according to the characteristics and requirements of the LED load.

[0038] The boost circuit is the basic part of the afterglow elimination circuit, which is used to boost the input voltage to meet the working requirements of the subsequent circuit. The specific implementation of the boost circuit can be selected according to actual needs, such as using a DC-DC boost module, etc. The buck circuit is connected to the output end of the boost circuit to reduce the boosted voltage to a voltage range suitable for the operation of the LED load. The specific implementation of the buck circuit can also be selected according to actual needs, such as using a linear buck circuit or a switch buck circuit. The input end of the dimming control circuit is used to obtain a dimming signal, which can be an analog signal or a digital signal from an external controller. The dimming control circuit adjusts the output voltage of the buck circuit according to the received dimming signal, thereby realizing the adjustment of the brightness of the LED load. The dimming control circuit may include components such as a potentiometer and a PWM signal generator to achieve accurate brightness adjustment. The power supply circuit is connected to the control circuit to provide the required power supply for the control circuit. In this embodiment, the power supply circuit includes a transistor Q2, a resistor R2 and a resistor R3. The first ends of resistors R2 and R3 are respectively connected to the base of transistor Q2, and the emitter of transistor Q2 is connected to the second end of resistor R2 and the power supply circuit to provide a stable power supply for the control circuit. The power supply circuit provides the required power supply for other parts of the afterglow elimination circuit.

[0039] In this embodiment, the power supply circuit includes a transistor Q2 connected to the second end of the resistor R1, and a resistor R2 and a resistor R3 connected to the transistor Q2. The stability and reliability of the power supply circuit are ensured by reasonable resistance value selection and circuit connection. The afterglow shutoff circuit is the core part of the afterglow elimination circuit, which is used to quickly shut off the afterglow of the LED load when needed. The afterglow shutoff circuit includes a diode D1 connected to the first end of the buck circuit, a MOS tube Q1 connected to the second end of the buck circuit, a resistor R1 and a Y1 capacitor CY1, and a diode D2 connected to the MOS tube Q1. By controlling the switching state of the MOS tube Q1, the afterglow of the LED load is turned off. When the input voltage is applied to the boost circuit, the boost circuit boosts it to a suitable voltage range and outputs it to the buck circuit. The buck circuit reduces the boosted voltage to a voltage range suitable for the operation of the LED load according to actual needs. The power supply circuit provides a stable power supply for other parts in the afterglow elimination circuit. When the afterglow of the LED load needs to be turned off, the control circuit sends a shutdown signal to the MOS tube Q1. After receiving the shutdown signal, MOS tube Q1 is quickly turned off, thereby cutting off the power supply circuit of the LED load and achieving rapid elimination of afterglow. At the same time, Y1 capacitor CY1 plays a role in filtering and stabilizing the voltage in the circuit, which helps to reduce the impact of voltage fluctuations on the LED load. Diodes D1 and D2 play a role in protecting the circuit to prevent the reverse flow of current from damaging the circuit. The dimming control circuit is used to receive the dimming signal and adjust the brightness of the LED load according to the dimming signal.

[0040] The control circuit controls the shut-off of the afterglow. When the afterglow of the LED load needs to be eliminated, the control circuit sends a control signal to control the switch state of the MOS tube Q1 through components such as the triode Q3. When the MOS tube Q1 is turned off, the power supply circuit of the LED load is cut off, thereby quickly eliminating the afterglow phenomenon. At the same time, components such as the Y1 capacitor CY1 can absorb and release charges, further stabilize the circuit operation, and improve the effect of eliminating the afterglow.

[0041] The afterglow elimination circuit provided in this embodiment has the characteristics of simple structure, precise control, and good afterglow elimination effect. The stability and reliability of the circuit are ensured through reasonable circuit design and component selection. In practical applications, the circuit can effectively eliminate the afterglow phenomenon of the LED load and improve the overall performance of the lighting system and user experience.

[0042] The specific embodiments described herein are merely examples of the spirit of the present invention. The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the present application. It should be noted that a technician in the technical field to which the present application belongs may make various modifications or supplements to the described specific embodiments or replace them in a similar manner, but will not deviate from the spirit of the present application or exceed the scope defined in the attached claims. For a person of ordinary skill in the art, multiple variations and improvements may also be made without departing from the concept of the present application. Therefore, the scope of protection of the present application shall be subject to the attached claims.

Claims

1. An afterglow elimination circuit, characterized in that: The afterglow shutdown circuit comprises an afterglow shutdown circuit, wherein the output end of the afterglow shutdown circuit is connected to the output circuit, the input end is respectively connected to the step-down circuit and the power supply circuit, the power supply circuit is connected to the control circuit, the step-down circuit is respectively connected to the dimming circuit and the boost circuit, and the afterglow shutdown circuit comprises a MOS tube Q1 connected to the output end of the step-down circuit, a transistor Q2 connected to the output end of the power supply circuit, and a transistor Q3 connected to the output end of the control circuit.

2. The afterglow elimination circuit according to claim 1, characterized in that: The source of the MOS tube Q1 is connected to the output end of the step-down circuit, the drain is connected to the output circuit through the cathode of the diode D2, and the gate is connected to the emitter of the transistor Q2.

3. An afterglow elimination circuit according to claim 1 or 2, characterized in that: The collector of the transistor Q2 is connected to the output end of the power supply circuit. The output end of the power supply circuit is connected to the power supply end. At the same time, the output end of the power supply circuit is connected to the base of the transistor Q2 through the resistor R2.

4. An afterglow elimination circuit according to claim 1 or 2, characterized in that: The base of the transistor Q2 is connected to the emitter of the transistor Q3 via the resistor R3, the collector of the transistor Q3 is grounded, the base of the transistor Q3 is connected to the control circuit via the resistor R4, and the base of the transistor Q3 is grounded via the resistor R5.

5. The afterglow elimination circuit according to claim 2, characterized in that: One end of the output end of the step-down circuit is connected to the output circuit through the anode of the diode D1, and the other end of the output end of the step-down circuit is grounded through the capacitor CY1.

6. The afterglow elimination circuit according to claim 1, characterized in that: It also includes a chip US2, the model of which is BP2879D. Pin 1 of the chip US2 is connected to the source of the MOS tube QS3 through a capacitor CS13, the gate of the MOS tube QS3 is connected to the emitter of the triode US6A, the collector of the triode US6A is connected to the power supply end through resistors RS45 and RS44 in sequence, and the drain of the MOS tube QS3 is connected to the power supply end through a resistor RS42.

7. The afterglow elimination circuit according to claim 6, characterized in that: Pin 2 of the chip US2 is grounded through resistor RS58 and connected to one end of inductor T3B. The other end of inductor T3B is connected to the power supply end through diode DS14 and resistor RS51 in sequence. Pin 2 is connected to the source of MOS tube QS3 through resistor RS58.

8. The afterglow elimination circuit according to claim 6, characterized in that: Pin 4 of the chip US2 is connected to the source of MOS tube QS3 through a parallel resistor RS50 and a capacitor CS9, and pin 7 is connected to MOS tube Q2 through a resistor RS28 and a cathode of a diode DS10, and pin 7 is connected to MOS tube Q2 through a resistor RS29.

9. The afterglow elimination circuit according to claim 6 or 8, characterized in that: Pin 6 of the chip US2 is connected to the source of the MOS tube QS3 through the capacitor CS14, and the pin 6 is connected to the gate of the MOS tube Q2 through the resistor RS30. The source of the MOS tube Q2 is grounded through the parallel resistors RS32, RS33, RS34 and RS40, and the drain of the MOS tube Q2 is connected to the power supply terminal.

10. The afterglow elimination circuit according to claim 6 or 7, characterized in that: The pin 8 of the chip US2 is connected to the source of the MOS tube QS3 through the capacitor EC3 and the capacitor CS16 connected in parallel. The pin 8 is connected to the power supply terminal and is connected to the pin 2 through the resistor RS57.

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