Non-isolated afterglow shutdown circuit and LED driving circuit

Abstract

The utility model relates to the field of LED drive power supply, concretely is a kind of non-isolation afterglow shutdown circuit and LED drive circuit, including relay RY1, relay RY2, VCC circuit and control circuit;The conducting end of relay RY1 is connected in series on the first line between input filter module and input rectifier module, and the conducting end of relay RY2 is connected in series on the second line between input filter module and input rectifier module;VCC circuit is parallel with input filter module, and is configured to be used to provide operating voltage for the coil end of relay RY1, the coil end of relay RY2 and control circuit;Control circuit is connected with the coil end of relay RY1 and the coil end of relay RY2, and is used to control the on-off of the coil end of relay RY1 and the coil end of relay RY2;Avoid the problem that LED load afterglow does not go off light and will be slightly bright after power off, with better safety protection effect.

Description

Technical Field

[0001] This utility model relates to the field of LED driver power supply, specifically to a non-isolated afterglow shutdown circuit and an LED driver circuit. Background Technology

[0002] In power supply systems for loads such as LEDs, afterglow (i.e., the load remains dimly lit after power failure) is a critical issue affecting user experience and system reliability. Currently, mainstream afterglow mitigation solutions have significant technical limitations: 1. Semiconductor device shutdown scheme This solution eliminates afterglow by cutting off the DC positive and negative terminals of the output terminal using semiconductor devices (such as MOSFETs and transistors). However, since semiconductor devices have inter-electrode junction capacitance, the residual charge in the capacitor will still provide a weak current to the load after power is cut off, resulting in incomplete afterglow elimination. In scenarios with high brightness sensitivity (such as bedroom lighting and indicator lights for precision equipment), the problem of persistent afterglow light is particularly prominent. 2. Traditional relay shutdown scheme This solution eliminates afterglow by cutting off the circuit with a single relay, but it has two major drawbacks: First, the relay selection is limited by its withstand voltage and current parameters. If the load power or input voltage exceeds the relay's rated value, it is prone to shutdown failure or device damage. Second, due to user installation habits, when the customer's AC power switch only turns off the neutral wire (N line) instead of the live wire (L line), there is still residual voltage on the live wire side in the circuit. The relay cannot completely cut off the power supply circuit, resulting in the load still being dimly lit after the lights are turned off, and the afterglow problem cannot be solved. In summary, the existing solutions have problems, and there is an urgent need for a solution that can solve the afterglow problem in switching scenarios and ensure reliable shutdown. Summary of the Invention

[0003] The purpose of this invention is to overcome the above-mentioned shortcomings and provide a non-isolated afterglow shutdown circuit and an LED driver circuit.

[0004] To achieve the above objectives, the specific solution of this utility model is as follows: A non-isolated persistence shutdown circuit is provided, located between an input filter module and an input rectifier module. It includes relays RY1 and RY2, a VCC circuit, and a control circuit. The conducting terminal of relay RY1 is connected in series in a first line between the input filter module and the input rectifier module, and the conducting terminal of relay RY2 is connected in series in a second line between the input filter module and the input rectifier module. The VCC circuit is connected in parallel with the input filter module and configured to provide operating voltage to the coil terminals of relays RY1 and RY2, as well as the control circuit. The control circuit is connected to the coil terminals of relays RY1 and RY2 and is used to control the on / off state of the coil terminals of relays RY1 and RY2.

[0005] Furthermore, the control circuit of this invention includes a control module and a transistor Q100; the collector of transistor Q100 is connected to the coil terminals of relay RY1 and relay RY2; the emitter of transistor Q100 is grounded; the base of transistor Q100 is connected to the control module; the control module is used to output a control signal to the base of transistor Q100 to control the conduction of transistor Q100.

[0006] Furthermore, the control module of this invention includes resistors R143, R144, and R145, and capacitor C204; the two ends of resistor R145 are respectively connected to the emitter and base of transistor Q100; the two ends of resistor R143 and capacitor C204 connected in parallel are respectively connected to the two ends of resistor R145; one end of resistor R144 is connected to one end of resistor R145; the other end of resistor R144 is connected to the control signal.

[0007] Furthermore, the control module of this invention also includes transistors Q207, Q203, Q204, and Q208, a voltage regulator U2, and a comparator U3; the collector of transistor Q207, the Vin pin of voltage regulator U2, and the VCC pin of comparator U3 are connected to the VCC circuit; the collector of transistor Q203 is connected to the VCC circuit through resistor R208; the emitter of transistor Q207 is used to output control signals and is connected to the other end of resistor R144 through diode D203; the base of transistor Q207 is connected to the emitter of transistor Q203 and then grounded through Zener diode ZD201; The base of transistor Q203 is connected to the VCC circuit through resistor R210 and grounded through resistor R211; the emitter of transistor Q204 is grounded, the collector is connected to the base of transistor Q203, and the base is grounded through resistor R213; the base of transistor Q208 is connected to the PWM signal, the collector is connected to the VCC circuit through resistor R315 and grounded through Zener diode ZD204, the emitter is grounded through resistor R501 and connected to the -IN pin of comparator U3 through resistor R316; the GND pin of voltage regulator U2 is grounded, and the Vout pin is connected to the +IN pin of comparator U3 through resistor R502; the +IN pin of comparator U3 is connected to the OUT pin through resistor R504 and grounded through resistor R503, the OUT pin is connected to the base of transistor Q204 through resistor R212, and the GND pin is grounded.

[0008] Furthermore, in this invention, a capacitor C503 is connected between the +IN pin and the GND pin of comparator U3; the VCC pin of comparator U3 is also grounded through a capacitor C504.

[0009] Furthermore, in this invention, the -IN pin of comparator U3 is grounded through capacitors C501 and C502 connected in parallel.

[0010] Furthermore, this utility model also includes a dimming conversion circuit, and the VCC circuit is also used to provide operating voltage for the dimming conversion circuit; The dimming conversion circuit includes a dimming conversion module and an optocoupler U302; the anode of the optocoupler U302 is connected to the VCC circuit through resistor R320 and diode D303; the cathode of the optocoupler U302 is connected to the output terminal of the dimming conversion module; the collector of the optocoupler U302 is connected to the VCC circuit through resistor R308, grounded through resistor R307, and also connected to the base of transistor Q208; the emitter of the optocoupler U302 is grounded; the output terminal of the dimming conversion module outputs a dimming PWM signal.

[0011] Furthermore, in this invention, a diode D111 is provided between the two ends of the coil of relay RY1; and a diode D112 is provided between the two ends of the coil of relay RY2.

[0012] Furthermore, the VCC circuit of this invention includes a first interface ACL, a second interface ACN, an auxiliary rectification and filtering module, an auxiliary power management chip U1, a first transformer T2A, a second transformer T3B, a first voltage module, and a second voltage module. The first interface ACL is connected to a first line, and the second interface ACN is connected to a second line. The input terminal of the auxiliary rectification and filtering module is connected to the first interface ACL and the second interface ACN. The output terminal of the auxiliary rectification and filtering module is connected to the auxiliary power management chip U1 and the primary winding of the second transformer T3B. The secondary winding of the second transformer T3B is connected to a dimming conversion circuit. The primary winding of the first transformer T2A is connected to the auxiliary power management chip U1. The secondary winding of the first transformer T2A is connected to the input terminal of the first voltage module. The output terminal of the first voltage module is connected to the input terminal of the second voltage module, the dimming conversion circuit, and the control circuit. The output terminal of the second voltage module is connected to the coil terminal of relay RY1 and the coil terminal of relay RY2.

[0013] This invention also provides an LED driving circuit, including the non-isolated afterglow shutdown circuit as described above.

[0014] The beneficial effects of this utility model are as follows: 1. Completely Eliminate Afterglow and Improve Load User Experience: This utility model's non-isolated afterglow shutdown circuit uses relays RY1 and RY2 connected in series on the L and N lines between the input filter module and the input rectifier module, respectively, forming a dual-path disconnection structure for the L and N lines. Compared to afterglow removal solutions using semiconductor devices, this completely avoids the problem of incomplete afterglow shutdown caused by the junction capacitance between semiconductor devices. Furthermore, regardless of whether the user's AC power switch turns off the L or N line, the control circuit will cut off the power supply to the two relay coils after the VCC circuit is de-energized, causing the L and N lines to disconnect synchronously. This achieves the effect of completely extinguishing the LED load's afterglow, avoiding the problem of the LED load remaining dimly lit after power is turned off. It ensures that the load can be instantly extinguished after power failure, meeting the needs of various application scenarios requiring afterglow control. 2. Enhanced safety performance and improved electrical safety: This utility model's non-isolated afterglow shutdown circuit places a relay between the input filter module and the input rectifier module, achieving the disconnection of the AC input main power supply. The dual-relay collaborative operation, compared to the traditional single-relay shutdown scheme, better handles different voltage and current conditions, reducing safety risks caused by relays failing to meet voltage or current requirements. Furthermore, after the AC input main power supply is disconnected, the subsequent LED load and related circuits are completely disconnected from the power grid. During circuit inspection, maintenance, or in case of abnormalities, personnel can avoid contact with live parts, providing better safety protection. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the circuit principle of the non-isolated afterglow shutdown circuit provided in this embodiment of the utility model; Figure 2 This is a schematic diagram of the circuit principle of relays RY1 and RY2 connected to the control circuit according to an embodiment of the present invention; Figure 3 This is a circuit diagram of a control circuit provided in an embodiment of the present invention; Figure 4 This is a circuit diagram of a dimming conversion circuit provided in an embodiment of the present invention; Figure 5 This is a circuit schematic diagram of a VCC circuit provided in an embodiment of the present invention; Explanation of reference numerals in the attached diagram: 100, VCC circuit; 200, control circuit; 201, control module; 300, dimming conversion circuit. Detailed Implementation

[0016] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but this is not to limit the scope of the present invention.

[0017] like Figures 1 to 5 As shown in this embodiment, a non-isolated persistence shutdown circuit is located between the input filtering module and the input rectifier module. It includes relays RY1 and RY2, a VCC circuit 100, and a control circuit 200. The conducting terminal of relay RY1 is connected in series on a first line between the input filtering module and the input rectifier module, and the conducting terminal of relay RY2 is connected in series on a second line between the input filtering module and the input rectifier module. The VCC circuit 100 is connected in parallel with the input filtering module and is configured to provide operating voltage to the coil terminals of relays RY1 and RY2, as well as the control circuit 200. The control circuit 200 is connected to the coil terminals of relays RY1 and RY2 and is used to control the on / off state of the coil terminals of relays RY1 and RY2.

[0018] Specifically, the input filtering module is an AC input filtering module, the input rectifier module is an AC input rectifier module, the first line is the L line, and the second line is the N line. The VCC circuit 100 is connected in parallel on the L line and the N line. In practical application, the non-isolated afterglow shutdown circuit of this embodiment connects the L line and the N line. The VCC circuit 100 supplies power to the coil terminals of relays RY1 and RY2, as well as the control circuit 200. The control circuit 200 controls the coil terminals of relays RY1 and RY2 to be energized and conduct, thereby making the conducting terminals of relays RY1 and RY2 conduct, connecting the line between the input filtering module and the input rectifier module, thus providing voltage for the subsequent LED load. When the L or N line is turned off, i.e., the power is turned off, the VCC circuit 100 is de-energized, causing the control circuit 200 to disconnect the coil terminals of relays RY1 and RY2. This disconnects the conducting terminals of both relays RY1 and RY2, thus disconnecting the line between the input filter module and the input rectifier module. This achieves a double disconnection of the L and N lines, completely extinguishing the afterglow of the LED load and avoiding the problem of the LED load remaining dimly lit after the power is turned off.

[0019] Because both the L and N lines are disconnected, the AC input main power supply to the drive is cut off, thus providing better safety protection.

[0020] like Figure 2 As shown, in the non-isolated afterglow shutdown circuit of this embodiment, a diode D111 is disposed between the two ends of the coil terminal of relay RY1; a diode D112 is disposed between the two ends of the coil terminal of relay RY2. This embodiment uses... like Figures 1 to 3 As shown, in this embodiment, the non-isolated persistence shutdown circuit includes a control circuit 200 comprising a control module 201 and a transistor Q100. The collector of transistor Q100 is connected to the coil terminals of relays RY1 and RY2. The emitter of transistor Q100 is grounded. The base of transistor Q100 is connected to the control module 201. The control module 201 outputs a control signal to the base of transistor Q100 to control the conduction of transistor Q100.

[0021] Specifically, when the L and N lines are connected, the control module 201 outputs a high-level control signal to the base of transistor Q100, causing transistor Q100 to conduct. This connects the coil terminals of relays RY1 and RY2, energizing their respective conducting terminals and thus connecting the circuit between the input filter module and the input rectifier module. When the L or N line is turned off, the control module 201 outputs a low-level control signal to the base of transistor Q100, turning off transistor Q100. This disconnects the energizing circuit between the coil terminals of relays RY1 and RY2, rendering them inactive. The conducting terminals of both relays are also disconnected, thus disconnecting the circuit between the input filter module and the input rectifier module. This achieves the complete elimination of afterglow by disconnecting both the L and N lines.

[0022] like Figure 3 As shown, in this embodiment of the non-isolated afterglow shutdown circuit, the control module 201 includes resistors R143, R144, and R145, and capacitor C204. The two ends of resistor R145 are connected to the emitter and base of transistor Q100, respectively. The two ends of resistor R143 and capacitor C204 connected in parallel are connected to the two ends of resistor R145, respectively. One end of resistor R144 is connected to one end of resistor R145. The other end of resistor R144 is connected to the control signal. This embodiment uses the above configuration to more stably control the switching of transistor Q100, thereby controlling relays RY1 and RY2.

[0023] like Figure 3 As shown, in this embodiment of the non-isolated persistence shutdown circuit, the control module 201 further includes transistors Q207, Q203, Q204, and Q208, a voltage regulator U2, and a comparator U3. The collector of transistor Q207, the Vin pin of voltage regulator U2, and the VCC pin of comparator U3 are connected to the VCC circuit 100. The collector of transistor Q203 is connected to the VCC circuit 100 through resistor R208. The emitter of transistor Q207 is used to output a control signal and is connected to the other end of resistor R144 through diode D203. The base of transistor Q207 is connected to the emitter of transistor Q203 and then grounded through Zener diode ZD201. The base of transistor Q203 is connected to VCC circuit 100 through resistor R210 and grounded through resistor R211; the emitter of transistor Q204 is grounded, the collector is connected to the base of transistor Q203, and the base is grounded through resistor R213; the base of transistor Q208 is connected to the PWM signal, the collector is connected to VCC circuit 100 through resistor R315 and grounded through Zener diode ZD204, and the emitter is grounded through resistor R501 and connected to the -IN pin of comparator U3 through resistor R316; the GND pin of voltage regulator U2 is grounded, and the Vout pin is connected to the +IN pin of comparator U3 through resistor R502; the +IN pin of comparator U3 is connected to the OUT pin through resistor R504 and grounded through resistor R503, the OUT pin is connected to the base of transistor Q204 through resistor R212, and the GND pin is grounded. Voltage regulator U2 provides a stable reference voltage to the +IN pin of comparator U3. The PWM signal is a control signal adapted to the dimming PWM signal. Transistor Q208 controls the input voltage at the -IN pin of the comparator based on the duty cycle of the PWM signal, thereby controlling the output level at the OUT pin of comparator U3. A higher duty cycle in the dimming PWM signal results in higher brightness for the LED load, and vice versa.

[0024] Specifically, when the L and N lines are connected, if the duty cycle of the PWM signal is less than the first threshold, a low voltage is input to the -IN pin of comparator U3, and a high level is output through the OUT pin of comparator U3, causing transistor Q204 to conduct. At this time, the base voltage of transistor Q203 is pulled low, transistor Q203 is cut off, and transistor Q207 is also cut off. At this time, a low-level control signal is input to the base of transistor Q100, transistor Q100 is cut off, thereby disconnecting the power supply lines of the coil terminals of relays RY1 and RY2. The coil terminals of relays RY1 and RY2 do not work, and the conducting terminals of RY1 and RY2 are both disconnected, thereby disconnecting the line between the input filter module and the input rectifier module, achieving the dimming and shutdown effect, and turning off the afterglow. If the duty cycle of the PWM signal is greater than the first threshold, a high voltage is input to the -IN pin of comparator U3, and a low level is output from the OUT pin of comparator U3. Transistor Q204 is cut off, and transistor Q203 is turned on, which in turn turns on transistor Q207. This inputs a high-level control signal to the base of transistor Q100, thereby connecting the energizing circuits of the coil terminals of relays RY1 and RY2 to maintain the operation of the LED load.

[0025] like Figure 3As shown, in the non-isolated persistence shutdown circuit of this embodiment, a capacitor C503 is connected between the +IN pin and the GND pin of comparator U3 to provide a reference voltage for the +IN pin of comparator U3; the VCC pin of comparator U3 is also grounded through capacitor C504 to provide a stable operating voltage for the VCC pin of comparator U3.

[0026] like Figure 3 As shown, in the non-isolated persistence shutdown circuit of this embodiment, the -IN pin of comparator U3 is also grounded through capacitors C501 and C502 connected in parallel. This embodiment uses the above configuration to provide a stable voltage signal to the -IN pin of comparator U3.

[0027] like Figure 1 and Figure 4 As shown, the non-isolated afterglow shutdown circuit of this embodiment also includes a dimming conversion circuit 300. The VCC circuit 100 is also used to provide operating voltage for the dimming conversion circuit 300. The dimming conversion circuit 300 includes a dimming conversion module and an optocoupler U302. The anode of the optocoupler U302 is connected to the VCC circuit 100 through a resistor R320 and a diode D303. The cathode of the optocoupler U302 is connected to the output terminal of the dimming conversion module. The collector of the optocoupler U302 is connected to the VCC circuit 100 through a resistor R308, grounded through a resistor R307, and connected to the base of a transistor Q208. The emitter of the optocoupler U302 is grounded. The output terminal of the dimming conversion module outputs a dimming PWM signal. The dimming conversion module can adopt the existing dimming conversion circuit 300 structure that outputs a dimming PWM signal.

[0028] Specifically, the dimming conversion circuit 300 is connected to an external dimmer. The dimming conversion module converts the external dimming signal into a dimming PWM signal. The dimming PWM signal is coupled to the receiving end of the optocoupler U302 through the transmitting end, thereby generating a PWM signal that matches the dimming PWM at the receiving end and inputting it to the base of the transistor Q208. This enables the relays RY1 and RY2 to be controlled according to the external dimming signal, achieving the dimming and turning-off effect and effectively avoiding the influence of afterglow.

[0029] like Figure 1 and Figure 5As shown, the non-isolated persistence shutdown circuit of this embodiment includes a VCC circuit 100 comprising a first interface ACL, a second interface ACN, an auxiliary rectifier and filter module, an auxiliary power management chip U1, a first transformer T2A, a second transformer T3B, a first voltage module, and a second voltage module. The first interface ACL is connected to a first line, and the second interface ACN is connected to a second line. The input terminal of the auxiliary rectifier and filter module is connected to the first interface ACL and the second interface ACN. The output terminal of the auxiliary rectifier and filter module is connected to the auxiliary power management chip U1 and the primary winding of the second transformer T3B. The secondary winding of the second transformer T3B is connected to the dimming conversion circuit 300. The primary winding of the first transformer T2A is connected to the auxiliary power management chip U1. The secondary winding of the first transformer T2A is connected to the input terminal of the first voltage module. The output terminal of the first voltage module is connected to the input terminal of the second voltage module, the dimming conversion circuit 300, and the control circuit 200. The output terminal of the second voltage module is connected to the coil terminal of relay RY1 and the coil terminal of relay RY2.

[0030] Specifically, the first interface ACL is connected to the L line, the second interface ACN is connected to the N line, the auxiliary rectification and filtering module can adopt existing rectification and filtering modules, such as a full-wave rectification circuit structure, and the auxiliary power management chip U1 can also adopt an existing power management circuit structure to output +12Vaux voltage on the secondary winding of the second transformer T3B and output ZDS+ voltage on the secondary winding of the second transformer T3B. For example, the first voltage module may include diode D202, electrolytic capacitor CE03, transistor Q206, Zener diode ZD202, capacitor C203, and resistor R201; the anode of diode D202 is connected to the ZDS+ voltage, and the cathode is connected to the anode of electrolytic capacitor CE03 and the collector of transistor Q206, and references the VDD1 voltage node; the base of transistor Q206 is connected to its collector through resistor R201, and grounded through Zener diode ZD202; the cathode of electrolytic capacitor CE03 is grounded; the emitter of transistor Q206 is grounded through capacitor C203, and leads out the VCCAUX voltage node. The collector of transistor Q207, the Vin pin of voltage regulator U2, and the VCC pin of comparator U3 are connected to the VCCAUX voltage node. The collector of transistor Q203 is connected to the VCCAUX voltage node through resistor R208. The base of transistor Q203 is connected to the VCCAUX voltage node through resistor R210. The collector of transistor Q208 is connected to the VCCAUX voltage node through resistor R315. The anode of optocoupler U302 is connected to the +12Vaux voltage through resistor R320 and diode D303. The collector of optocoupler U302 is connected to the VCCAUX voltage node through resistor R308.

[0031] For example, the second voltage module may include a transistor Q205, a resistor R202, a Zener diode ZD203, and a capacitor C205; the collector of transistor Q205 is connected to the VDD1 voltage node, the base of transistor Q205 is connected to its collector through resistor R202, and is also grounded through the Zener diode ZD203; the emitter of transistor Q205 is grounded through capacitor C205, and the VCCRY voltage node is led out; the coil terminals of relays RY1 and RY2 are both connected to the VCCRY voltage node, thereby providing operating voltage for relays RY1 and RY2.

[0032] like Figures 1 to 5 As shown, this embodiment also provides an LED driving circuit, including the non-isolated persistence shutdown circuit as described above. This embodiment, by employing the non-isolated persistence shutdown circuit of the above embodiment, possesses all the beneficial effects of the non-isolated persistence shutdown circuit of this embodiment, which will not be elaborated further here.

[0033] The above description is only a preferred embodiment of the present utility model. Therefore, any equivalent changes or modifications made to the structure, features and principles described in the claims of the present utility model patent application are included within the protection scope of the present utility model patent application.

Claims

1. A non-isolated afterglow shutdown circuit, characterized in that, The non-isolated afterglow shutdown circuit is located between the input filter module and the input rectifier module, and includes relays RY1 and RY2, a VCC circuit, and a control circuit. The conducting terminal of relay RY1 is connected in series in the first line between the input filter module and the input rectifier module, and the conducting terminal of relay RY2 is connected in series in the second line between the input filter module and the input rectifier module. The VCC circuit is connected in parallel with the input filter module and is configured to provide operating voltage to the coil terminals of relays RY1 and RY2, as well as the control circuit. The control circuit is connected to the coil terminals of relays RY1 and RY2 and is used to control the on / off state of the coil terminals of relays RY1 and RY2.

2. The non-isolated persistence shutdown circuit according to claim 1, characterized in that, The control circuit includes a control module and a transistor Q100; the collector of transistor Q100 is connected to the coil terminals of relay RY1 and relay RY2; the emitter of transistor Q100 is grounded; the base of transistor Q100 is connected to the control module; the control module is used to output a control signal to the base of transistor Q100 to control the conduction of transistor Q100.

3. The non-isolated afterglow shutdown circuit according to claim 2, characterized in that, The control module includes resistors R143, R144, and R145, and capacitor C204. The two ends of resistor R145 are connected to the emitter and base of transistor Q100, respectively. The two ends of resistor R143 and capacitor C204 connected in parallel are connected to the two ends of resistor R145, respectively. One end of resistor R144 is connected to one end of resistor R145. The other end of resistor R144 is connected to the control signal.

4. The non-isolated afterglow shutdown circuit according to claim 3, characterized in that, The control module also includes transistors Q207, Q203, Q204, and Q208, voltage regulator U2, and comparator U3. The collector of transistor Q207, the Vin pin of voltage regulator U2, and the VCC pin of comparator U3 are connected to the VCC circuit. The collector of transistor Q203 is connected to the VCC circuit through resistor R208. The emitter of transistor Q207 is used to output the control signal and is connected to the other end of resistor R144 through diode D203. The base of transistor Q207 is connected to the emitter of transistor Q203 and then grounded through Zener diode ZD201. The base of transistor Q203 is connected to the VCC circuit through resistor R210 and grounded through resistor R211; the emitter of transistor Q204 is grounded, the collector is connected to the base of transistor Q203, and the base is grounded through resistor R213; the base of transistor Q208 is connected to the PWM signal, the collector is connected to the VCC circuit through resistor R315 and grounded through Zener diode ZD204, the emitter is grounded through resistor R501 and connected to the -IN pin of comparator U3 through resistor R316; the GND pin of voltage regulator U2 is grounded, and the Vout pin is connected to the +IN pin of comparator U3 through resistor R502; the +IN pin of comparator U3 is connected to the OUT pin through resistor R504 and grounded through resistor R503, the OUT pin is connected to the base of transistor Q204 through resistor R212, and the GND pin is grounded.

5. The non-isolated afterglow shutdown circuit according to claim 4, characterized in that, A capacitor C503 is connected between the +IN pin and the GND pin of comparator U3; the VCC pin of comparator U3 is also grounded through capacitor C504.

6. The non-isolated afterglow shutdown circuit according to claim 4, characterized in that, The -IN pin of comparator U3 is also grounded through capacitors C501 and C502 connected in parallel.

7. The non-isolated afterglow shutdown circuit according to claim 4, characterized in that, It also includes a dimming conversion circuit, and the VCC circuit is also used to provide the operating voltage for the dimming conversion circuit; The dimming conversion circuit includes a dimming conversion module and an optocoupler U302; the anode of the optocoupler U302 is connected to the VCC circuit through resistor R320 and diode D303; the cathode of the optocoupler U302 is connected to the output terminal of the dimming conversion module; the collector of the optocoupler U302 is connected to the VCC circuit through resistor R308, grounded through resistor R307, and also connected to the base of transistor Q208; the emitter of the optocoupler U302 is grounded; the output terminal of the dimming conversion module outputs a dimming PWM signal.

8. The non-isolated afterglow shutdown circuit according to claim 1, characterized in that, A diode D111 is installed between the two ends of the coil of relay RY1; a diode D112 is installed between the two ends of the coil of relay RY2.

9. The non-isolated afterglow shutdown circuit according to claim 7, characterized in that, The VCC circuit includes a first interface ACL, a second interface ACN, an auxiliary rectification and filtering module, an auxiliary power management chip U1, a first transformer T2A, a second transformer T3B, a first voltage module, and a second voltage module. The first interface ACL is connected to the first line, and the second interface ACN is connected to the second line; The input of the auxiliary rectifier and filter module is connected to the first interface ACL and the second interface ACN; The output of the auxiliary rectifier and filter module is connected to the auxiliary power management chip U1 and the primary winding of the second transformer T3B; The secondary winding of the second transformer T3B is connected to the dimming conversion circuit; the primary winding of the first transformer T2A is connected to the auxiliary power management chip U1; the secondary winding of the first transformer T2A is connected to the input terminal of the first voltage module; the output terminal of the first voltage module is connected to the input terminal of the second voltage module, the dimming conversion circuit, and the control circuit; the output terminal of the second voltage module is connected to the coil terminal of relay RY1 and the coil terminal of relay RY2.

10. An LED driving circuit, characterized in that, Includes the non-isolated afterglow shutdown circuit as described in any one of claims 1 to 9.

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