A protection circuit for a power supply module

Abstract

The present invention relates to the technical field of power supply protection, and proposes a protection circuit for a power supply module, including a surge protection circuit, an APFC circuit, an LLC circuit, a synchronous rectification circuit, and an overvoltage protection circuit. The surge protection circuit, the APFC circuit, the LLC circuit, and the synchronous rectification circuit are connected in sequence, and the overvoltage protection circuit is connected to the LLC circuit. When a fault occurs inside the power supply or an overvoltage phenomenon occurs at the output due to improper user operation, the power supply protection circuit proposed by the present invention protects the power supply to prevent damage to the subsequent power-consuming equipment.

Description

Technical Field

[0001] The present invention relates to the technical field of power protection, and particularly relates to a protection circuit for a power supply module. Background Art

[0002] In a power supply system, the most likely faults are short circuit, overload, grounding, and lightning strike, etc. In order to ensure the safe and reliable operation of the power supply system, a protection circuit must be installed to prevent damage to the subsequent connected devices when a fault occurs. Among them, there are many reasons for overvoltage in the circuit, such as the turn-off of switching devices, the closing and opening of power switches, etc. Due to the existence of parasitic inductance in the circuit, voltage spikes will be generated by current mutations caused by various reasons, resulting in overvoltage. When the terminal voltage exceeds a certain value, the resistance will decrease sharply, thereby suppressing the transient overvoltage. Summary of the Invention

[0003] The purpose of the present invention is to provide a protection circuit for a power supply module, which can effectively avoid damage to subsequent devices caused by faults in the power circuit.

[0004] In order to achieve the above-mentioned invention purpose, the embodiments of the present invention provide the following technical solutions:

[0005] A protection circuit for a power supply module includes a surge protection circuit, an APFC circuit, an LLC circuit, a synchronous rectification circuit, and an overvoltage protection circuit. The surge protection circuit, APFC circuit, LLC circuit, and synchronous rectification circuit are connected in sequence, and the overvoltage protection circuit is connected to the LLC circuit.

[0006] Furthermore, the surge protection circuit includes a primary lightning protection circuit, a secondary lightning protection circuit, a MEI circuit, and a discharge tube. The primary lightning protection circuit, secondary lightning protection circuit, and MEI circuit are connected in sequence, and the discharge tube is connected between the primary lightning protection circuit and the MEI circuit; the primary lightning protection circuit is connected to the alternating current.

[0007] Furthermore, the APFC circuit includes a boost circuit, a power supply chip, and an integration circuit connected to the power supply chip. The boost circuit is connected to the surge protection circuit, and the power supply chip and the integration circuit are respectively connected to the boost circuit.

[0008] Furthermore, the model of the power supply chip is L6561.

[0009] Furthermore, the LLC circuit includes a primary input circuit, a power resonance circuit, and a dual transformer circuit connected in sequence. The primary input circuit is connected to the APFC circuit; the dual transformer circuit includes a transformer T3, and the secondary side of the transformer T3 includes a first secondary side and a second secondary side, and the first secondary side and the second secondary side are connected in parallel.

[0010] Further, the power resonance circuit includes a power resonance chip, and the model of the power resonance chip is MCZ5211ST.

[0011] Further, the synchronous rectification circuit includes a first rectification circuit and a second rectification circuit which are connected to each other, and the first rectification circuit and the second rectification circuit are respectively connected to the LLC circuit.

[0012] Further, the first rectification circuit includes a first synchronous rectification chip, and the model of the first synchronous rectification chip is TEA1792TS; the second rectification circuit includes a second synchronous rectification chip, and the model of the second synchronous rectification chip is TEA1792TS.

[0013] Further, the overvoltage protection circuit includes a drive protection circuit and a power drive circuit connected to the drive protection circuit, and the drive protection circuit is connected to the LLC circuit.

[0014] Further, the power drive circuit includes a power drive chip, and the model of the power drive chip is TSM1014.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0016] (1) When a fault occurs inside the power supply or an overvoltage phenomenon occurs at the output due to improper user operation, the power protection circuit proposed by the present invention protects the power supply to prevent damage to the subsequent power-consuming equipment.

[0017] (2) The surge protection circuit of the present invention can provide safety protection for various electronic devices, instruments, and communication lines. When a spike current or voltage suddenly occurs in the loop of the device or instrument or the communication line due to external interference, the surge protection circuit can conduct and shunt in a very short time, thereby avoiding damage to the device caused by the surge. Among them, the MEI circuit is an electromagnetic compatibility circuit for anti-electromagnetic interference, which can absorb electromagnetic interference and convert it into heat for consumption.

[0018] (3) In the synchronous rectification circuit of the present invention, dedicated power transistors M4 and M5 with extremely low on-resistance are used to replace traditional diodes to reduce rectification losses, greatly improve the efficiency of the synchronous rectification chip, and there is no four-region voltage caused by the Schottky barrier voltage. Description of the Drawings

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as a limitation of the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0020] Figure 1 This is the block diagram of the present invention module;

[0021] Figure 2 This is the schematic diagram of the surge protection circuit of the present invention;

[0022] Figure 3 This is the schematic diagram of the APFC circuit of the present invention;

[0023] Figure 4 This is the schematic diagram of the LLC circuit of the present invention;

[0024] Figure 5 This is the schematic diagram of the synchronous rectification circuit of the present invention;

[0025] Figure 6 This is the schematic diagram of the overvoltage protection circuit of the present invention. Specific embodiments

[0026] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Usually, the components of the embodiments of the present invention described and shown in the accompanying drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed present invention, but only represents the selected embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0027] It should be noted that: similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. At the same time, in the description of the present invention, terms such as "first", "second", etc. are only used for distinguishing descriptions, and cannot be understood as indicating or implying relative importance, or implying any such actual relationship or order between these entities or operations.

[0028] Embodiment 1:

[0029] The present invention is realized through the following technical solutions. As Figure 1 shown, a protection circuit for a power supply module includes a surge protection circuit, an APFC circuit, an LLC circuit, a synchronous rectification circuit, and an overvoltage protection circuit. The surge protection circuit, the APFC circuit, the LLC circuit, and the synchronous rectification circuit are connected in sequence, and the overvoltage protection circuit is connected to the LLC circuit. When a fault occurs inside the power supply or an overvoltage phenomenon occurs at the output due to improper user operation, the power supply protection circuit proposed by the present invention protects the power supply to prevent damage to the subsequent power-consuming equipment.

[0030] Further, as Figure 2 shown, the surge protection circuit includes a primary lightning protection circuit, a secondary lightning protection circuit, an MEI circuit, and a discharge tube. The primary lightning protection circuit, the secondary lightning protection circuit, and the MEI circuit are connected in sequence. The discharge tube is connected between the primary lightning protection circuit and the MEI circuit. The primary lightning protection circuit is connected to the alternating current. When the input voltage exceeds the normal operating voltage instantaneously, a surge occurs. A surge is a severe pulse that occurs within only a few millionths of a second. Possible causes of surges include heavy equipment, short circuits, power switching, or large engines. The surge protection circuit in this embodiment can effectively absorb the sudden huge energy to protect the devices connected to the subsequent stage from being damaged. On the other hand, the surge protection circuit can also provide safety protection for various electronic devices, instruments, and communication lines. When a spike current or voltage suddenly occurs in the loop of the device or instrument or the communication line due to external interference, the surge protection circuit can conduct and shunt in an extremely short time, thereby avoiding damage to the device caused by the surge. The MEI circuit is an electromagnetic compatibility circuit for anti-electromagnetic interference. It can absorb electromagnetic interference and convert it into heat for consumption.

[0031] As Figure 2 shown, the surge protection circuit includes resistors R1 to R3, capacitors C1 to C3, sliding resistors RL1 to RL3, a fuse F1, current transformers HL1 and HL2, an AC chip, an inductor L1, and a discharge tube GDT. One end of the fuse F1 is connected to 220V alternating current. The other end of the fuse F1 is respectively connected to one end of the sliding resistor RL1, one end of the sliding resistor RL2, one end of the resistor R1, and the current transformer HL1. The other end of the resistor R1 is connected in series with the resistors R2 and R3. The other end of the sliding resistor RL1 is respectively connected to the other end of the resistor R3 and the current transformer HL1. The capacitors C2 and C3 are connected in series and then connected in parallel with the current transformer HL1, the capacitor C1, and the current transformer HL2. The current transformer HL2 is connected to the input end of the AC chip. The input end of the AC chip is connected to the inductor L1 and then used as the output end of the surge protection circuit. One end of the discharge tube GDT is connected to the primary lightning protection circuit, and the other end is connected to the MEI circuit.

[0032] It should be noted that the discharge tube GDT is a ceramic gas discharge tube and is connected in parallel in the surge protection circuit. When the circuit is operating normally, the discharge tube GDT is in a high-resistance state. When there is an overvoltage, the inert gas inside is broken down, so that most of the energy is dissipated, and the discharge tube GDT returns to normal, thus playing a role in protecting the circuit.

[0033] Further, as Figure 3As shown, the APFC circuit includes a boost circuit, a power supply chip, and an integration circuit connected to the power supply chip. The boost circuit is connected to a surge protection circuit, and the power supply chip and the integration circuit are respectively connected to the boost circuit. The model of the power supply chip is L6561.

[0034] As Figure 3 shown, the APFC circuit includes resistors R4 to R19, capacitors C4 to C10, a sliding resistor RL4, diodes D1 to D3, a boost inductor HL3, a transistor M1, and a power supply chip. The output terminals of the surge protection circuit are respectively connected to one end of resistor R4, the anode of diode D1, and the boost inductor HL3. Resistor R4 is successively connected in series with resistor R5 and resistor R6. The other end of resistor R6 is respectively connected to resistor R16, capacitor C9, and the MULT pin of the power supply chip. The other ends of resistor R16 and capacitor C9 are both grounded. The boost inductor HL3 is also connected to the anode of diode D2, one end of resistor R7, and the drain of transistor M1. The cathode of diode D1 is connected to the sliding resistor RL4. The cathode of diode D2 is connected to one end of the sliding resistor RL4. The other end of the sliding resistor RL4 is respectively connected to one end of capacitor C5 and one end of resistor R8, and serves as the output terminal of the APFC circuit. The COMP pin of the power supply chip is respectively connected to one end of resistor R9 and one end of capacitor C8. The other end of resistor R9 is connected to one end of capacitor C7. Resistor R8 is successively connected in series with resistor R10 and resistor R11. The INV pin of the power supply chip is respectively connected to the other end of capacitor C7, the other end of capacitor C8, the other end of resistor R11, one end of resistor R12, and one end of resistor R13. The other ends of resistor R12 and resistor R13 are both grounded. The GD pin of the power supply chip is respectively connected to one end of resistor R14 and one end of resistor R15. The other end of resistor R15 is connected to the cathode of diode D3. The other end of resistor R14 is respectively connected to the anode of diode D3, one end of resistor R17, and the gate of transistor M1. The CS pin of the power supply chip is respectively connected to one end of capacitor C10 and one end of resistor R18. The other end of capacitor C10 is grounded. The source of transistor M1 is respectively connected to the other end of resistor R17, the other end of resistor R18, and one end of resistor R19. The other end of resistor R19 is grounded.

[0035] It should be noted that after normal operation, the input voltage of the APFC circuit is greater than the output voltage of the AC chip, and the diode D1 remains in the cut-off state after startup. Therefore, a slow recovery diode can be selected for D1. However, the diode D2 is in a high-frequency switching state, so a fast recovery diode should be selected for D2. Generally speaking, the reverse recovery speed of a diode and the peak forward conduction current are mutually restrictive. The slow recovery diode can withstand a much larger forward conduction current. Therefore, a large surge current will pass through the diode D1, thereby protecting the diode D5 from being burned out by overcurrent and preventing too much current from flowing through the diode D5.

[0036] The MULT pin of the power supply chip L6561 is the input terminal of the internal multiplier. In this APFC circuit, the input voltage is divided by resistors R4, R5, and R6 and then input from this pin. The GD pin of the power supply chip L6561 is the gate drive output terminal, which is the output terminal of the gate drive pulse for the transistor M1, and controls the conduction and cutoff of the transistor M1 by outputting a pulse voltage. The ZCD pin of the power supply chip L6561 is the zero-current detection input terminal, which is the current detection output terminal on the boost inductor HL3. When the boost circuit operates in the critical conduction mode, it detects the current of the boost inductor HL3. Once the current drops to zero, the transistor M1 is turned on to enter the next pulse cycle.

[0037] Furthermore, as Figure 4 shown, the LLC circuit includes a primary input circuit, a power resonance circuit, and a dual-transformer circuit connected in sequence. The primary input circuit is connected to the APFC circuit. The dual-transformer circuit includes a transformer T3. The secondary side of the transformer T3 includes a first secondary side and a second secondary side, and the first secondary side and the second secondary side are connected in parallel. The power resonance circuit includes a power resonance chip, and the model of the power resonance chip is MCZ5211ST. The LLC circuit adjusts the frequency through the power resonance chip to achieve a constant output voltage.

[0038] As Figure 4As shown, the LLC circuit includes resistors R20 to R40, capacitors C10 to C11 to C19, diodes D4 to D11, a slide resistor RL5, a power resonance chip, transistors M2 and M3, and a dual transformer T3; the HVG pin of the power resonance chip is connected to one end of resistor R34, and the other end of resistor R34 is respectively connected to one end of resistor R35 and the cathode of diode D8. The other end of resistor R35 is respectively connected to the anode of diode D8, one end of resistor R36, and the gate of transistor M2. The drain of transistor M2 is respectively connected to the output end of the APFC circuit and the cathode of diode D10; the OUT pin of the power resonance chip is respectively connected to one end of capacitor C18 and one end of resistor R37. The other end of capacitor C18 is connected to the VBOOT pin of the power resonance chip; the source of transistor M2 is respectively connected to one end of resistor R36, the other end of resistor R37, the drain of transistor M3, and the primary side 1 pin of the dual transformer T3; the LVG pin of the power resonance chip is connected to one end of resistor R40, and the other end of resistor R40 is respectively connected to one end of resistor R39 and the cathode of diode D9. The other end of resistor R39 is respectively connected to the other end of diode D9, one end of resistor R38, and the gate of transistor M3. The source of transistor M3 is respectively connected to the other end of resistor R38, the anode of diode D11, and the primary side 2 pin of the dual transformer; the secondary sides of the dual transformer are connected in parallel and used as the output end of the LLC circuit.

[0039] Furthermore, as Figure 5 shown, the synchronous rectification circuit includes a first rectification circuit and a second rectification circuit that are connected to each other. The first rectification circuit and the second rectification circuit are respectively connected to the LLC circuit; the first rectification circuit includes a first synchronous rectification chip, and the model of the first synchronous rectification chip is TEA1792TS; the second rectification circuit includes a second synchronous rectification chip, and the model of the second synchronous rectification chip is TEA1792TS. In this synchronous rectification circuit, dedicated power transistors M4 and M5 with extremely low on-resistance are used to replace traditional diodes to reduce rectification losses, greatly improving the efficiency of the synchronous rectification chip, and there is no four-region voltage caused by the Schottky barrier voltage.

[0040] As Figure 5As shown, the synchronous rectification circuit includes resistor R41 to resistor R46, resistor R65, resistor R66, capacitor C20 to capacitor C23, diode D12, diode D13, transistor M4, transistor M5, the first synchronous rectification chip, and the second synchronous rectification chip; the 3rd pin of the secondary side of the dual transformer T3 is respectively connected to one end of resistor R65, one end of capacitor C22, and the drain of transistor M4, the other end of capacitor C22 is connected to one end of resistor R66, the other end of resistor R65 is connected to the SRSENCE pin of the first synchronous rectification chip, the gate of transistor M4 is respectively connected to one end of resistor R41, one end of resistor R42, and the anode of diode D12, the source of transistor M4 is respectively connected to the other end of resistor R66 and the other end of resistor R41, the cathode of diode D12 and the other end of resistor R42 are respectively connected to the DRIVER pin of the first synchronous rectification chip; the 6th pin of the secondary side of the dual transformer T3 is respectively connected to one end of resistor R45, one end of capacitor C23, and the drain of transistor M5, the other end of resistor R45 is connected to the SRSENCE pin of the second synchronous rectification chip, the other end of capacitor C23 is connected to one end of resistor R46, the other end of resistor R46 is respectively connected to the source of transistor M5 and one end of resistor R44, the other end of resistor R44 is respectively connected to the gate of transistor M5, one end of resistor R43, and the anode of diode D13, the other end of resistor R43 and the cathode of diode D13 are respectively connected to the DRIVER pin of the second synchronous rectification chip.

[0041] Furthermore, as Figure 6 shown, the overvoltage protection circuit includes a drive protection circuit and a power drive circuit connected to the drive protection circuit, and the drive protection circuit is connected to the LLC circuit; the power drive circuit includes a power drive chip, and the model of the power drive chip is TSM1014. The output end of the drive protection circuit outputs a voltage of 30 - 36V.

[0042] As Figure 6As shown, the overvoltage protection circuit includes resistors R49 to R64, capacitors C24 to C33, diodes D14 to D18, potentiometers RL6, potentiometer RL7, current transformer HL4, power driver chip, and optocoupler; the output end of the LLC circuit is respectively connected to the cathode of diode D12 and capacitor C24, and capacitors C24, C25, C26, resistor R49, resistor R50, resistor R51, capacitor C27, current transformer HL4, resistor R54, and capacitor C28 are connected in parallel in sequence. Resistor R52 is connected between resistor R51 and capacitor C27, and resistor R53 is in parallel with resistor R52; the anode of diode D14 is connected to the cathode of diode D15, the anode of diode D15 is connected to one end of resistor R48, and the other end of resistor R48 is respectively connected to resistor R47 and the optocoupler. The optocoupler is also respectively connected to one end of resistor R55, the anode of diode D16, the anode of diode D17, and one end of capacitor C31. The other end of resistor R55 is connected to the VCC pin of the power driver chip. The cathode of diode D16 is respectively connected to the Ccout pin of the power driver chip and one end of capacitor C34. The other end of capacitor C34 is respectively connected to the Cc- pin of the power driver chip and one end of resistor R61; the cathode of diode D17 is respectively connected to the Cvout pin of the power driver chip and one end of resistor R60. The other end of resistor R60 is connected to one end of capacitor C33. The other end of capacitor C33 is respectively connected to the Cv- pin of the power driver chip, one end of resistor R63, and one end of resistor R56. The other end of resistor R56 is connected to current transformer HL4, and capacitor C32 is in parallel with resistor R56; the other end of resistor R63 is respectively connected to potentiometer RL7 and resistor R64; the other end of resistor R61 is connected to the anode of diode D18, and the cathode of diode D18 is respectively connected to the Cc+ pin of the power driver chip. The Cc+ pin of the power driver chip is also respectively connected to one end of resistor R59, one end of potentiometer RL6, and one end of resistor R58. The other end of resistor R59 is grounded. The other end of potentiometer RL6 is respectively connected to the other end of resistor R58 and one end of resistor R57. The other end of resistor R57 is respectively connected to capacitor C29 and the Verf pin of the power driver chip.

[0043] As described above, the above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A protection circuit for a power supply module, characterized in that: It includes a surge protection circuit, an APFC circuit, an LLC circuit, a synchronous rectification circuit, and an overvoltage protection circuit. The surge protection circuit, APFC circuit, LLC circuit, and synchronous rectification circuit are connected in sequence, and the overvoltage protection circuit is connected to the LLC circuit; The surge protection circuit includes a primary lightning protection circuit, a secondary lightning protection circuit, an MEI circuit, and a discharge tube. The primary lightning protection circuit, secondary lightning protection circuit, and MEI circuit are connected in sequence, and the discharge tube is connected between the primary lightning protection circuit and the MEI circuit; the primary lightning protection circuit is connected to the alternating current; The surge protection circuit includes resistors R1 to R3, capacitors C1 to C3, sliding resistors RL1 to RL3, a fuse F1, current transformers HL1 and HL2, an AC chip, an inductor L1, and a discharge tube GDT. One end of the fuse F1 is connected to 220V alternating current, and the other end of the fuse F1 is respectively connected to one end of the sliding resistor RL1, one end of the sliding resistor RL2, one end of the resistor R1, and the current transformer HL1. The other end of the resistor R1 is connected in series with the resistors R2 and R3, and the other end of the sliding resistor RL1 is respectively connected to the other end of the resistor R3 and the current transformer HL1; the capacitors C2 and C3 are connected in series and then connected in parallel with the current transformer HL1, the capacitor C1, and the current transformer HL2. The current transformer HL2 is connected to the input end of the AC chip, and the input end of the AC chip is connected to the inductor L1 and then used as the output end of the surge protection circuit; one end of the discharge tube GDT is connected to the primary lightning protection circuit, and the other end is connected to the MEI circuit; The APFC circuit includes a boost circuit, a power supply chip, and an integration circuit connected to the power supply chip. The boost circuit is connected to the surge protection circuit, and the power supply chip and the integration circuit are respectively connected to the boost circuit; The APFC circuit includes resistors R4 to R19, capacitors C4 to C10, a sliding resistor RL4, diodes D1 to D3, a boost inductor HL3, a transistor M1, and a power supply chip; the output terminals of the surge protection circuit are respectively connected to one end of resistor R4, the anode of diode D1, and the boost inductor HL3. Resistor R4 is successively connected in series with resistor R5 and resistor R6. The other end of resistor R6 is respectively connected to resistor R16, capacitor C9, and the MULT pin of the power supply chip. The other ends of resistor R16 and capacitor C9 are both grounded; the boost inductor HL3 is also connected to the anode of diode D2, one end of resistor R7, and the drain of transistor M1. The cathode of diode D1 is connected to the sliding resistor RL4. The cathode of diode D2 is connected to one end of the sliding resistor RL4. The other end of the sliding resistor RL4 is respectively connected to one end of capacitor C5 and one end of resistor R8, and serves as the output terminal of the APFC circuit; the COMP pin of the power supply chip is respectively connected to one end of resistor R9 and one end of capacitor C8. The other end of resistor R9 is connected to one end of capacitor C7. Resistor R8 is successively connected in series with resistor R10 and resistor R11. The INV pin of the power supply chip is respectively connected to the other end of capacitor C7, the other end of capacitor C8, the other end of resistor R11, one end of resistor R12, and one end of resistor R13. The other ends of resistor R12 and resistor R13 are both grounded; the GD pin of the power supply chip is respectively connected to one end of resistor R14 and one end of resistor R15. The other end of resistor R15 is connected to the cathode of diode D3. The other end of resistor R14 is respectively connected to the anode of diode D3, one end of resistor R17, and the gate of transistor M1. The CS pin of the power supply chip is respectively connected to one end of capacitor C10 and one end of resistor R18. The other end of capacitor C10 is grounded. The source of transistor M1 is respectively connected to the other end of resistor R17, the other end of resistor R18, and one end of resistor R19. The other end of resistor R19 is grounded; The LLC circuit includes a primary input circuit, a power supply resonance circuit, and a dual transformer circuit connected in sequence. The primary input circuit is connected to the APFC circuit; the dual transformer circuit includes a transformer T3. The secondary side of the transformer T3 includes a first secondary side and a second secondary side, and the first secondary side and the second secondary side are connected in parallel; The LLC circuit includes resistors R20 to R40, capacitors C10 to C11 to C19, diodes D4 to D11, a sliding resistor RL5, a power resonance chip, transistors M2, M3, and a dual transformer T3. The HVG pin of the power resonance chip is connected to one end of resistor R34, and the other end of resistor R34 is respectively connected to one end of resistor R35 and the cathode of diode D8. The other end of resistor R35 is respectively connected to the anode of diode D8, one end of resistor R36, and the gate of transistor M2. The drain of transistor M2 is respectively connected to the output terminal of the APFC circuit and the cathode of diode D10. The OUT pin of the power resonance chip is respectively connected to one end of capacitor C18 and one end of resistor R37, and the other end of capacitor C18 is connected to the VBOOT pin of the power resonance chip. The source of transistor M2 is respectively connected to one end of resistor R36, the other end of resistor R37, the drain of transistor M3, and the primary side pin 1 of the dual transformer T3. The LVG pin of the power resonance chip is connected to one end of resistor R40, and the other end of resistor R40 is respectively connected to one end of resistor R39 and the cathode of diode D9. The other end of resistor R39 is respectively connected to the other end of diode D9, one end of resistor R38, and the gate of transistor M3. The source of transistor M3 is respectively connected to the other end of resistor R38, the anode of diode D11, and the primary side pin 2 of the dual transformer. The secondary sides of the dual transformer are connected in parallel to serve as the output terminal of the LLC circuit. The synchronous rectification circuit includes a first rectification circuit and a second rectification circuit that are connected to each other. The first rectification circuit and the second rectification circuit are respectively connected to the LLC circuit. The synchronous rectification circuit includes resistors R41 to R46, resistor R65, resistor R66, capacitors C20 to C23, diodes D12, D13, transistors M4, M5, a first synchronous rectification chip, and a second synchronous rectification chip; the secondary side pin 3 of the dual transformer T3 is respectively connected to one end of resistor R65, one end of capacitor C22, and the drain of transistor M4. The other end of capacitor C22 is connected to one end of resistor R66. The other end of resistor R65 is connected to the SRSENCE pin of the first synchronous rectification chip. The gate of transistor M4 is respectively connected to one end of resistor R41, one end of resistor R42, and the anode of diode D12. The source of transistor M4 is respectively connected to the other end of resistor R66 and the other end of resistor R41. The cathode of diode D12 and the other end of resistor R42 are respectively connected to the DRIVER pin of the first synchronous rectification chip; the secondary side pin 6 of the dual transformer T3 is respectively connected to one end of resistor R45, one end of capacitor C23, and the drain of transistor M5. The other end of resistor R45 is connected to the SRSENCE pin of the second synchronous rectification chip. The other end of capacitor C23 is connected to one end of resistor R46. The other end of resistor R46 is respectively connected to the source of transistor M5 and one end of resistor R44. The other end of resistor R44 is respectively connected to the gate of transistor M5, one end of resistor R43, and the anode of diode D13. The other end of resistor R43 and the cathode of diode D13 are respectively connected to the DRIVER pin of the second synchronous rectification chip; The overvoltage protection circuit includes a drive protection circuit and a power supply drive circuit connected to the drive protection circuit, and the drive protection circuit is connected to the LLC circuit; The overvoltage protection circuit includes resistors R49 to R64, capacitors C24 to C33, diodes D14 to D18, potentiometers RL6, potentiometer RL7, current transformer HL4, a power supply driver chip, and an optocoupler; the output terminal of the LLC circuit is respectively connected to the cathode of diode D12 and capacitor C24, and capacitors C24, C25, C26, resistor R49, resistor R50, resistor R51, capacitor C27, current transformer HL4, resistor R54, and capacitor C28 are connected in parallel in sequence. Resistor R52 is connected between resistor R51 and capacitor C27, and resistor R53 is in parallel with resistor R52; the anode of diode D14 is connected to the cathode of diode D15, the anode of diode D15 is connected to one end of resistor R48, the other end of resistor R48 is respectively connected to resistor R47 and the optocoupler, and the optocoupler is also respectively connected to one end of resistor R55, the anode of diode D16, the anode of diode D17, and one end of capacitor C31. The other end of resistor R55 is connected to the VCC pin of the power supply driver chip, the cathode of diode D16 is respectively connected to the Ccout pin of the power supply driver chip and one end of capacitor C34, and the other end of capacitor C34 is respectively connected to the Cc- pin of the power supply driver chip and one end of resistor R61; the cathode of diode D17 is respectively connected to the Cvout pin of the power supply driver chip and one end of resistor R60, the other end of resistor R60 is connected to one end of capacitor C33, and the other end of capacitor C33 is respectively connected to the Cv- pin of the power supply driver chip, one end of resistor R63, and one end of resistor R56. The other end of resistor R56 is connected to current transformer HL4, and capacitor C32 is in parallel with resistor R56; the other end of resistor R63 is respectively connected to potentiometer RL7 and resistor R64; the other end of resistor R61 is connected to the anode of diode D18, the cathode of diode D18 is respectively connected to the Cc+ pin of the power supply driver chip, and the Cc+ pin of the power supply driver chip is also respectively connected to one end of resistor R59, one end of potentiometer RL6, and one end of resistor R58. The other end of resistor R59 is grounded, the other end of potentiometer RL6 is respectively connected to the other end of resistor R58 and one end of resistor R57, and the other end of resistor R57 is respectively connected to capacitor C29 and the Verf pin of the power supply driver chip.

2. The protection circuit for a power supply module according to claim 1, characterized in that: The model of the power supply chip is L6561.

3. The protection circuit for a power supply module according to claim 1, characterized in that: The power supply driver circuit includes a power supply driver chip, and the model of the power supply driver chip is TSM1014.

4. The protection circuit for a power supply module according to claim 1, characterized in that: The first rectification circuit includes a first synchronous rectification chip, and the model of the first synchronous rectification chip is TEA1792TS; the second rectification circuit includes a second synchronous rectification chip, and the model of the second synchronous rectification chip is TEA1792TS.

5. The protection circuit for a power supply module according to claim 1, characterized in that: The power supply driver circuit includes a power supply driver chip, and the model of the power supply driver chip is TSM1014.

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