Overvoltage protection circuit, method and power supply system

Abstract

The application discloses an overvoltage protection circuit, an overvoltage protection method and a power supply system. The overvoltage protection circuit comprises a voltage monitoring circuit, which is used for outputting a thyristor gate signal to a thyristor when an overvoltage of a voltage detection point is detected, and the thyristor gate signal is used for controlling the thyristor to be turned on. A first resistor and a second resistor are connected in series between a direct current power supply end and a power supply control chip power supply end. The direct current power supply end is used for providing a holding current for the thyristor when the thyristor is turned on, so as to ensure that the thyristor can be reliably turned on. A cathode of the thyristor is grounded, and an anode of the thyristor is connected to a midpoint of the first resistor and the second resistor. A first end of an energy storage module is grounded, and a second end of the energy storage module is connected to the midpoint of the first resistor and the second resistor. The energy storage module is used for discharging through the thyristor when the thyristor is reliably turned on, and cutting off the power supply output of the power supply control chip. The technical scheme can reliably cut off the power supply output of the circuit system when an overvoltage occurs, so as to prolong the service life of internal components of the circuit system.

Description

Technical Field

[0001] This application relates to the field of circuit safety technology, and in particular to an overvoltage protection circuit, method and power supply system. Background Technology

[0002] Currently, when an overvoltage condition occurs in a circuit system, the overvoltage protection circuit is usually used to bring the system to a safe state. Commonly used overvoltage protection circuits typically employ a comparator and a MOSFET to monitor the safety-related voltages of the system. When the system experiences an overvoltage, the comparator activates, triggering the MOSFET and other safety monitoring links to cut off the system power supply and maintain the system voltage within a safe range. However, most switching power supplies are flyback power supplies. After the overvoltage protection circuit activates, it usually cuts off the power supply to the flyback power supply control chip. At this time, the power supply system will enter a hiccup state. The hiccup state will cause the circuit system to be repeatedly powered on and off, repeatedly impacting the internal components of the circuit system and affecting their lifespan. Summary of the Invention

[0003] The main purpose of this application is to provide an overvoltage protection circuit that reliably cuts off the power supply output of the circuit system in the event of overvoltage, thereby improving the service life of the internal components of the circuit system.

[0004] To achieve the above objectives, this application proposes an overvoltage protection circuit, which includes:

[0005] A voltage monitoring circuit is used to output a thyristor gating signal to the thyristor when an overvoltage is detected at the voltage detection point. The thyristor gating signal is used to control the thyristor to turn on.

[0006] The first resistor and the second resistor are connected in series between the DC power supply terminal and the power supply terminal of the power control chip. The DC power supply terminal is used to provide a sustaining current to the thyristor when the thyristor is turned on, so as to ensure that the thyristor is reliably turned on.

[0007] A thyristor, wherein the cathode of the thyristor is grounded and the anode of the thyristor is connected to the midpoint between the first resistor and the second resistor;

[0008] An energy storage module, wherein the first terminal of the energy storage module is grounded and the second terminal of the energy storage module is connected to the midpoint of the first resistor and the second resistor, and the energy storage module is used to discharge through the thyristor when the thyristor is turned on, so as to cut off the power supply output of the power supply terminal of the power control chip.

[0009] Optionally, the energy storage module includes a diode and an energy storage unit.

[0010] The first end of the energy storage unit is grounded, and the second end of the energy storage unit is connected to the positive terminal of the diode and the power supply terminal of the power control chip.

[0011] The negative terminal of the diode is connected to the midpoint between the first resistor and the second resistor.

[0012] Optionally, when the thyristor is reliably turned on, the energy storage unit is used to discharge through the thyristor and the diode; when the thyristor is not reliably turned on, the energy storage unit is used to store energy based on the power supply output of the power supply terminal of the power control chip.

[0013] Optionally, the voltage monitoring circuit includes an overvoltage detection circuit and an optocoupler.

[0014] The overvoltage detection circuit is used to output an optocoupler control signal to the optocoupler when an overvoltage is detected at the voltage detection point, wherein the optocoupler control signal is a low-level signal;

[0015] The optocoupler is used to turn on when it receives the optocoupler control signal and output the thyristor gate signal to the thyristor, wherein the thyristor gate signal is a high-level signal.

[0016] Optionally, the overvoltage detection circuit includes a comparator and a reference power supply.

[0017] The overvoltage detection circuit includes a comparator and a reference power supply.

[0018] The reference power supply is used to output a reference voltage signal to the comparator;

[0019] The negative input terminal of the comparator is connected to the voltage detection point, the positive input terminal of the comparator is connected to the output terminal of the reference power supply, and the output terminal of the comparator is connected to the optocoupler. The comparator is used to compare the voltage signal at the voltage detection point with the reference voltage signal, and generates the optocoupler control signal when it is determined that the voltage detection point is overvoltage.

[0020] To achieve the above objectives, this application also provides an overvoltage protection circuit method applied to the aforementioned overvoltage protection circuit, the overvoltage protection method comprising:

[0021] When an overvoltage is detected at the voltage detection point, a thyristor gating signal is output to the thyristor, wherein the thyristor gating signal is used to control the thyristor to conduct.

[0022] A sustaining current is provided to the thyristor through a DC power supply terminal, wherein the sustaining current is used to maintain the reliable conduction of the thyristor;

[0023] When the thyristor is reliably turned on, the power supply output of the power supply terminal of the power control chip is cut off.

[0024] Optionally, the energy storage module includes a diode and an energy storage unit, and the overvoltage protection method further includes:

[0025] When the thyristor is reliably turned on, the energy storage unit is controlled to discharge through the diode and the thyristor, thereby cutting off the power supply output of the power supply terminal of the power control chip;

[0026] When the thyristor is not reliably turned on, the energy storage unit is charged by the power supply output of the power supply terminal of the power control chip.

[0027] Optionally, the voltage monitoring circuit includes an overvoltage detection circuit and an optocoupler. The step of outputting a thyristor gating signal to the thyristor when an overvoltage is detected at the voltage detection point includes:

[0028] If an overvoltage is detected at the voltage detection point by the overvoltage detection circuit, an optocoupler control signal is output to the optocoupler through the overvoltage detection circuit, wherein the optocoupler control signal is a low-level signal;

[0029] The optocoupler is turned on according to the optocoupler control signal to generate the thyristor gate signal, wherein the thyristor gate signal is a high-level signal.

[0030] Optionally, the overvoltage detection circuit includes a comparator and a reference power supply. If an overvoltage is detected at the voltage detection point by the overvoltage detection circuit, a control signal for the optocoupler is output through the overvoltage detection circuit, including:

[0031] Acquire the voltage signal generated by the voltage detection point and the reference voltage signal output by the reference power supply;

[0032] When an overvoltage is detected at the voltage detection point, the comparator compares the voltage signal with the reference voltage signal to generate the optocoupler control signal.

[0033] The comparator outputs an optocoupler control signal to the optocoupler.

[0034] To achieve the above objectives, this application also proposes a power supply system in which the stepper motor driver includes the overvoltage protection circuit described above, and will not be repeated here.

[0035] The technical solution of this application comprises an overvoltage protection circuit consisting of a voltage monitoring circuit, a first resistor, a second resistor, a thyristor, and an energy storage module. In this overvoltage protection circuit, the first resistor and the second resistor are connected in series between the DC power supply terminal and the power supply terminal of the power control chip. The cathode of the thyristor is grounded, and the anode of the thyristor is connected to the midpoint of the first and second resistors. The first terminal of the energy storage module is grounded, and the second terminal of the energy storage module is connected to the midpoint of the first and second resistors. Therefore, when the voltage monitoring circuit detects an overvoltage at the detection point, it outputs a thyristor gating signal to the thyristor, controlling the thyristor to conduct. Subsequently, the energy storage module discharges through the thyristor, rapidly lowering the potential at the midpoint between the first resistor and the second resistor, thereby cutting off the power output of the power supply terminal of the power control chip. The DC power supply terminal provides a sustaining current to the thyristor, ensuring its reliable and continuous conduction. Therefore, the power supply terminal of the power control chip will reliably remain in the off state, and the circuit system will reliably enter a safe state. There is no hiccup oscillation in the power supply, which avoids the repeated power-on of the circuit system caused by hiccups, thus preventing repeated impacts on the internal components of the circuit system and extending the service life of the internal components. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0037] Figure 1 This is a circuit functional block diagram of one embodiment of the overvoltage protection circuit in this application;

[0038] Figure 2 This is a circuit functional block diagram of an embodiment of the overvoltage protection circuit when the energy storage module in this application is composed of diodes and energy storage units;

[0039] Figure 3 This is a circuit functional block diagram of an embodiment of the overvoltage protection circuit when the voltage monitoring circuit in this application consists of an overvoltage detection circuit and an optocoupler;

[0040] Figure 4 This is a schematic diagram of the voltage monitoring circuit in one embodiment of the overvoltage protection circuit of this application;

[0041] Figure 5 This is a schematic diagram of the circuit structure of the overvoltage cutoff circuit in one embodiment of the overvoltage protection circuit of this application;

[0042] Figure 6 This is a flowchart of an embodiment of the overvoltage protection method in this application.

[0043] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings.

[0044] Explanation of icon numbers:

[0045] Detailed Implementation

[0046] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0047] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0048] Furthermore, the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed in this application.

[0049] This application proposes an overvoltage protection circuit. In one embodiment of this application, the overvoltage protection circuit includes a voltage monitoring circuit 100, a first resistor R1 and a second resistor R2, a thyristor T1, and an energy storage module 200.

[0050] Reference Figure 1In this embodiment, the overvoltage protection circuit consists of two parts: a voltage monitoring circuit 100 and an overvoltage cutoff circuit. The overvoltage cutoff circuit includes a first resistor R1, a second resistor R2, a thyristor T1, and an energy storage module 200. The input terminal of the voltage monitoring circuit 100 is connected to a voltage detection point, and the output terminal of the voltage monitoring circuit 100 is connected to the gate of the thyristor T1. The first resistor R1 and the second resistor R2 are connected in series. One end of the first resistor R1 is connected to the DC power supply terminal, and the other end of the first resistor R1 is connected to the second resistor R2. One end of the second resistor R2 is connected to the power supply terminal of the power control chip, and the other end of the second resistor R2 is connected to the first resistor R1. The cathode of the thyristor T1 is grounded, and the anode of the thyristor T1 is connected to the midpoint between the first resistor R1 and the second resistor R2. The first terminal of the energy storage module 200 is grounded, and the second terminal of the energy storage module 200 is connected to the midpoint between the first resistor R1 and the second resistor R2.

[0051] When the voltage monitoring circuit 100 detects an overvoltage at the voltage detection point, it generates a thyristor gating signal based on the voltage signal generated at the voltage detection point and outputs the thyristor gating signal to the gate of the thyristor T1 to control the anode and cathode of the thyristor T1 to conduct. This thyristor gating signal is used to control the conduction of the thyristor T1. When the thyristor T1 is conducting, the energy storage module 200 discharges through the thyristor T1, thereby quickly pulling down the potential at the midpoint of the first resistor R1 and the second resistor R2, i.e., pulling it down from a high level. The power supply terminal of the power control chip is pulled low to cut off the power output of the power supply terminal. At the same time, the DC power supply terminal provides a sustaining current to the thyristor T1 through the first resistor R1. This sustaining current keeps the thyristor T1 in a continuous conducting state, thus ensuring that the thyristor T1 is reliably turned on. Since the thyristor T1 is reliably turned on, the power supply terminal of the power control chip will remain stable at a low level, ensuring that the power system will not enter a hiccup state. This power system can be a servo power system.

[0052] As an example, before the thyristor T1 is turned on, the power supply terminal of the power control chip supplies power to the energy storage module 200, and the energy storage module 200 stores energy under the power supply output of the power supply terminal of the power control chip.

[0053] As an example, refer to Figure 2The energy storage module 200 includes a diode D1 and an energy storage unit 201. The first end of the energy storage unit 201 is grounded, and the second end of the energy storage unit 201 is connected to the positive terminal of the diode D1 and the power supply terminal of the power control chip. The negative terminal of the diode D1 is connected to the midpoint between the first resistor R1 and the second resistor R2. The diode D1 is used to ensure that no path is formed between the DC power supply terminal and the energy storage unit 201. When the thyristor T1 is reliably turned on, the energy storage unit 201 and the thyristor T1 are unidirectionally connected. The energy storage unit 201 will discharge through the diode D1 and the thyristor T1, thereby quickly pulling down the potential at the midpoint of the first resistor R1 and the second resistor R2, that is, from a high level to a low level, thereby pulling down the power supply terminal of the power control chip to a low potential. Before the thyristor T1 is reliably turned on, a path is formed between the power supply terminal of the power control chip and the energy storage unit 201, and the energy storage unit 201 will store energy under the power output of the power supply terminal of the power control chip.

[0054] As an example, refer to Figure 3 The voltage monitoring circuit 100 includes an overvoltage detection circuit 101 and an optocoupler U2. The overvoltage detection circuit 101, upon detecting an overvoltage at a voltage detection point, generates a corresponding optocoupler control signal based on the voltage signal at the detection point and outputs the optocoupler control signal to the optocoupler U2. The optocoupler U2, upon receiving the optocoupler control signal, outputs a thyristor gate signal to the thyristor T1, wherein the optocoupler control signal controls the optocoupler U2 to conduct. The optocoupler control signal can be a low-level signal, and the thyristor gate signal can be a high-level signal.

[0055] As an example, the optocoupler control signal can be a low-level signal, and the overvoltage detection circuit 101 includes a comparator U1 and a reference power supply VREF. Figure 4 , Figure 4This is a schematic diagram of the circuit structure of the voltage monitoring circuit 100. The reference power supply VREF is used to output a reference voltage signal to the comparator U1. The negative input terminal of the comparator U1 is connected to the voltage detection point, the positive input terminal of the comparator U1 is connected to the output terminal of the reference power supply VREF, the output terminal of the comparator U1 is connected to the negative terminal of the diode D2, and the positive terminal of the diode D2 is connected to the input terminal of the optocoupler U2. When the voltage detection point is determined to be overvoltage, the comparator U1 compares the voltage signal generated at the voltage detection point with the reference voltage signal, which will generate a high-level signal. At this time, the diode D2 will not conduct, and the high-level signal will not be transmitted to the optocoupler U2. When the voltage detection point is overvoltage, the comparator U1 compares the voltage signal generated at the voltage detection point with the reference voltage signal, which will generate a low-level signal. At this time, the diode D2 will conduct, and the low-level signal will be transmitted to the optocoupler U2 as an optocoupler control signal. After receiving the low-level signal, the optocoupler U2 will conduct and output a thyristor gate signal Ug to the thyristor T1.

[0056] As an example, the voltage at the voltage detection point fluctuates between 0 and 5V, and the reference power supply voltage VREF is 1.2V. If the voltage exceeds 5V, comparator U1 compares the voltage signal generated at the voltage detection point with the reference voltage signal. Since the voltage signal is greater than 5V, comparator U1 will output a low-level signal at point A. This low-level signal will be transmitted to optocoupler U2 through diode D2, controlling optocoupler U2 to conduct and generating a thyristor gate signal Ug. If the voltage does not exceed 5V, comparator U1 compares the voltage signal generated at the voltage detection point with the reference voltage signal. Since the normal voltage signal is not greater than 5V, comparator U1 will output a high-level signal at point A. This high-level signal will be blocked by diode D2 and will not control optocoupler U2 to conduct.

[0057] As an example, refer to Figure 4 as well as Figure 5 , Figure 5The diagram below shows the structure of the overvoltage cutoff circuit in this embodiment. The energy storage unit 201 is composed of an energy storage capacitor C1, a diode D3, a resistor R5, and a heat sink connected in series. One end of the energy storage capacitor C1 is grounded, and the other end of the energy storage capacitor C1 is connected to the positive terminal of the diode D1 and the power supply terminal VCC of the power control chip U43. The negative terminal of the diode D1 is connected to the midpoint B of the first resistor R1 and the second resistor R2. The anode of the thyristor T1 is connected to the midpoint B of the first resistor R1 and the second resistor R2. The cathode of the thyristor T1 is grounded. The gate of the thyristor T1 is connected to the output terminal of the optocoupler U2. When there is an overvoltage, the voltage monitoring circuit 100 outputs a thyristor gate signal Ug to the gate of the thyristor T1. One end of the first resistor R1 is connected to the DC power supply terminal VIN (310VDC / 540V DC), and the other end of the first resistor R1 is connected to one end of the second resistor R2. The other end of the second resistor R2 is connected to the power supply terminal VCC of the power control chip U43. Therefore, when the thyristor T1 is turned on, the energy storage capacitor C1 changes from a charging state to a discharging state. The energy storage capacitor C1 will discharge through the diode D1 and the thyristor T1, thereby quickly pulling down the potential of point B, that is, quickly pulling point B from a high level to a low level. As a result, the power supply terminal VCC of the power control chip U43 will be at a low level, thus cutting off the power supply output of the power supply terminal VCC of the power control chip U43. At the same time, when the thyristor T1 is turned on, the DC power supply terminal VIN (310VDC / 540V DC)... DC provides a sustaining current to thyristor T1 through the first resistor R1. This sustaining current keeps thyristor T1 in a continuous conducting state, ensuring reliable conduction of thyristor T1. As a result, the power supply terminal VCC of power control chip U43 remains in a low level, thus reliably cutting off the power supply output of power supply terminal VCC of power control chip U43.

[0058] The technical solution of this application embodiment comprises an overvoltage protection circuit consisting of a voltage monitoring circuit, a first resistor, a second resistor, a thyristor, and an energy storage module. In this overvoltage protection circuit, the first resistor and the second resistor are connected in series between the DC power supply terminal and the power supply terminal of the power control chip. The cathode of the thyristor is grounded, and the anode of the thyristor is connected to the midpoint of the first and second resistors. The first terminal of the energy storage module is grounded, and the second terminal of the energy storage module is connected to the midpoint of the first and second resistors. Therefore, when the voltage monitoring circuit detects an overvoltage at the voltage detection point, it outputs a thyristor gating signal to the thyristor, controlling the thyristor to conduct. After the circuit is turned on, the energy storage module will discharge through the thyristor, quickly lowering the potential at the midpoint between the first resistor and the second resistor, thereby cutting off the power output of the power supply terminal of the power control chip. The DC power supply terminal will provide a sustaining current to the thyristor to keep it reliably and continuously conducting. Therefore, the power supply terminal of the power control chip will be reliably and continuously kept off, and the circuit system will reliably enter a safe state. There is no hiccup oscillation state in the power supply, which can avoid the situation where the circuit system is repeatedly powered on due to hiccups, causing repeated impacts on the internal components of the circuit system. Therefore, the service life of the internal components of the circuit system is improved.

[0059] This application also provides an overvoltage protection circuit method, applied to the above-mentioned overvoltage protection circuit, with reference to... Figure 6 , and combined Figures 1 to 5 The overvoltage protection method includes:

[0060] Step S10: When an overvoltage is detected at the voltage detection point, a thyristor gating signal is output to the thyristor, wherein the thyristor gating signal is used to control the thyristor to conduct.

[0061] Step S20: Provide a sustaining current to the thyristor through the DC power supply terminal, wherein the sustaining current is used to maintain the reliable conduction of the thyristor;

[0062] Step S30: When the thyristor is reliably turned on, cut off the power supply output of the power supply terminal of the power control chip.

[0063] The energy storage module includes a diode and an energy storage unit, and the overvoltage protection method further includes:

[0064] Step A10: When the thyristor is reliably turned on, control the energy storage unit to discharge through the diode and the thyristor, thereby cutting off the power supply output of the power supply terminal of the power control chip;

[0065] Step A20: When the thyristor is not reliably turned on, the energy storage unit is charged by the power supply output of the power supply terminal of the power control chip.

[0066] The voltage monitoring circuit includes an overvoltage detection circuit and an optocoupler. When an overvoltage is detected at the voltage detection point, the step of outputting a thyristor gating signal to the thyristor includes:

[0067] Step S11: If an overvoltage is detected at the voltage detection point by the overvoltage detection circuit, an optocoupler control signal is output to the optocoupler by the overvoltage detection circuit, wherein the optocoupler control signal is a low-level signal;

[0068] Step S12: Control the optocoupler to turn on according to the optocoupler control signal to generate the thyristor gate signal, wherein the thyristor gate signal is a high-level signal.

[0069] The overvoltage detection circuit includes a comparator and a reference power supply. If an overvoltage is detected at the voltage detection point by the overvoltage detection circuit, a control signal for the optocoupler is output to the optocoupler through the overvoltage detection circuit, including:

[0070] Step S111: Obtain the voltage signal generated by the voltage detection point and the reference voltage signal output by the reference power supply;

[0071] Step S112: When it is determined that the voltage detection point is overvoltage, the voltage signal and the reference voltage signal are compared by the comparator to generate the optocoupler control signal;

[0072] Step S113: Output an optocoupler control signal to the optocoupler through the comparator.

[0073] It is understood that, since the overvoltage protection circuit described above is used in the overvoltage protection method, the embodiments of the overvoltage protection method include all the technical solutions of all embodiments of the overvoltage protection circuit described above, and the technical effects achieved are exactly the same, so they will not be repeated here.

[0074] In addition, this application also provides a power supply system, which includes a switching power supply and the overvoltage protection circuit described above. It is understood that since the overvoltage protection circuit described above is used in the power supply system, the embodiments of the power supply system include all the technical solutions of all embodiments of the overvoltage protection circuit described above, and the technical effects achieved are exactly the same, so they will not be repeated here.

[0075] The above description is merely a preferred embodiment of this application and does not limit the patent scope of this application. Any equivalent structural transformations made based on the content of this application's specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.

Claims

1. An overvoltage protection circuit, characterized in that, The overvoltage protection circuit includes: A voltage monitoring circuit is used to output a thyristor gating signal to the thyristor when an overvoltage is detected at the voltage detection point. The thyristor gating signal is used to control the thyristor to turn on. The first resistor and the second resistor are connected in series between the DC power supply terminal and the power supply terminal of the power control chip. The DC power supply terminal is used to provide a sustaining current to the thyristor when the thyristor is turned on, so as to ensure that the thyristor is reliably turned on. A thyristor, wherein the cathode of the thyristor is grounded and the anode of the thyristor is connected to the midpoint between the first resistor and the second resistor; An energy storage module, wherein the first terminal of the energy storage module is grounded and the second terminal of the energy storage module is connected to the midpoint of the first resistor and the second resistor, and the energy storage module is used to discharge through the thyristor when the thyristor is turned on, so as to cut off the power supply output of the power supply terminal of the power control chip; The energy storage module includes a diode and an energy storage unit. The first terminal of the energy storage unit is grounded, and the second terminal of the energy storage unit is connected to the positive terminal of the diode and the power supply terminal of the power control chip. The negative terminal of the diode is connected to the midpoint of the first resistor and the second resistor. When the thyristor is reliably turned on, the energy storage unit is used to discharge through the thyristor and the diode. When the thyristor is not reliably turned on, the energy storage unit is used to store energy based on the power supply output of the power supply terminal of the power control chip.

2. The overvoltage protection circuit as described in claim 1, characterized in that, The energy storage unit consists of an energy storage capacitor, a third diode, a resistor, and a heat sink connected in series. One end of the energy storage capacitor is grounded, and the other end of the energy storage capacitor is connected to the positive terminal of the diode and the power supply terminal of the power control chip.

3. The overvoltage protection circuit as described in claim 1, characterized in that, The voltage monitoring circuit includes an overvoltage detection circuit and an optocoupler. The overvoltage detection circuit is used to output an optocoupler control signal to the optocoupler when an overvoltage is detected at the voltage detection point, wherein the optocoupler control signal is a low-level signal; The optocoupler is used to turn on when it receives the optocoupler control signal and output the thyristor gate signal to the thyristor, wherein the thyristor gate signal is a high-level signal.

4. The overvoltage protection circuit as described in claim 3, characterized in that, The overvoltage detection circuit includes a comparator and a reference power supply. The reference power supply is used to output a reference voltage signal to the comparator; The negative input terminal of the comparator is connected to the voltage detection point, the positive input terminal of the comparator is connected to the output terminal of the reference power supply, and the output terminal of the comparator is connected to the optocoupler. The comparator is used to compare the voltage signal at the voltage detection point with the reference voltage signal, and generates the optocoupler control signal when it is determined that the voltage detection point is overvoltage.

5. An overvoltage protection method, characterized in that, The overvoltage protection method, applied to any one of claims 1-3, comprises: When an overvoltage is detected at the voltage detection point, a thyristor gating signal is output to the thyristor, wherein the thyristor gating signal is used to control the thyristor to conduct. A sustaining current is provided to the thyristor through a DC power supply terminal, wherein the sustaining current is used to maintain the reliable conduction of the thyristor; When the thyristor is reliably turned on, the power supply output of the power supply terminal of the power control chip is cut off.

6. The overvoltage protection method as described in claim 5, characterized in that, The energy storage module includes a diode and an energy storage unit, and the overvoltage protection method further includes: When the thyristor is reliably turned on, the energy storage unit is controlled to discharge through the diode and the thyristor, thereby cutting off the power supply output of the power supply terminal of the power control chip; When the thyristor is not reliably turned on, the energy storage unit is charged by the power supply output of the power supply terminal of the power control chip.

7. The overvoltage protection method as described in claim 5, characterized in that, The voltage monitoring circuit includes an overvoltage detection circuit and an optocoupler. When an overvoltage is detected at the voltage detection point, the step of outputting a thyristor gating signal to the thyristor includes: If an overvoltage is detected at the voltage detection point by the overvoltage detection circuit, an optocoupler control signal is output to the optocoupler through the overvoltage detection circuit, wherein the optocoupler control signal is a low-level signal; The optocoupler is turned on according to the optocoupler control signal to generate the thyristor gate signal, wherein the thyristor gate signal is a high-level signal.

8. The overvoltage protection method as described in claim 7, characterized in that, The overvoltage detection circuit includes a comparator and a reference power supply. If an overvoltage is detected at the voltage detection point by the overvoltage detection circuit, a control signal for the optocoupler is output to the optocoupler through the overvoltage detection circuit, including: Acquire the voltage signal generated by the voltage detection point and the reference voltage signal output by the reference power supply; When an overvoltage is detected at the voltage detection point, the comparator compares the voltage signal with the reference voltage signal to generate the optocoupler control signal. The comparator outputs an optocoupler control signal to the optocoupler.

9. A power supply system, characterized in that, The power supply system includes: a switching power supply and an overvoltage protection circuit as described in any one of claims 1-4.

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