DC power supply surge protection circuit and device

Abstract

The invention provides a DC power supply surge protection circuit and device, and is applied to the technical field of circuits, the DC power supply surge protection circuit is arranged between a DC power supply input interface and a post-stage circuit, and the DC power supply surge protection circuit comprises an inductor, a voltage difference trigger unit and a switch unit; a first end of the inductor is connected with the DC power supply input interface, and a second end of the inductor is connected with a post-stage circuit through the switch unit; the first end of the switch unit is connected with the second end of the inductor, the second end of the switch unit is connected with a post-stage circuit, and the third end of the switch unit is connected with the third end of the differential pressure trigger unit; the first end of the voltage difference trigger unit is connected with the DC power supply input interface, and the second end of the voltage difference trigger unit is connected with the first end of the switch unit. The invention aims to realize high-power DCIN negative voltage surge protection with low cost.

Description

Technical Field

[0001] The present application relates to the field of circuit technologies, and particularly to a DC power surge protection circuit and device. Background Art

[0002] In a DC power supply system, a negative voltage surge can cause a sudden drop in the voltage of the DCIN (Direct Current Input, DC power input interface), which in turn can cause problems such as shutdown / restart of the products connected to the subsequent stage.

[0003] There are two types of traditional negative voltage surge protection means: connecting a diode in series on the DCIN and adding a surge protection chip to the DCIN circuit. However, in practical applications, the method of connecting a diode in series will cause obvious power loss, especially in high-power application scenarios, this loss is particularly significant, and the method of adding a surge protection chip has the problem that the cost is too high to be popularized.

[0004] In summary, how to achieve high-power DCIN negative voltage surge protection at a low cost has become an urgent technical problem in this field. Summary of the Invention

[0005] The present application proposes a DC power surge protection circuit, aiming to achieve high-power DCIN negative voltage surge protection at a low cost.

[0006] To achieve the above object, the present application proposes a DC power surge protection circuit, which is arranged between the DC power input interface and the subsequent circuit. The DC power surge protection circuit includes an inductor, a voltage difference trigger unit, and a switch unit; The first end of the inductor is connected to the DC power input interface, and the second end of the inductor is connected to the subsequent circuit through the switch unit; The first end of the switch unit is connected to the second end of the inductor, the second end of the switch unit is connected to the subsequent circuit, and the third end of the switch unit is connected to the third end of the voltage difference trigger unit; The first end of the voltage difference trigger unit is connected to the DC power input interface, and the second end of the voltage difference trigger unit is connected to the first end of the switch unit.

[0007] In one embodiment, the voltage difference trigger unit includes a first resistor and a triode. The first end of the voltage difference trigger unit is the first end of the first resistor, the second end of the voltage difference trigger unit is the emitter of the triode, and the third end of the voltage difference trigger unit is the collector of the triode; The second end of the first resistor is connected to the base of the triode.

[0008] In one embodiment, the switching unit includes a PMOS transistor (positive Metal-Oxide-Semiconductor Field-Effect Transistor) and a voltage dividing circuit. The first end of the switching unit is the drain of the PMOS transistor, the second end of the switching unit is the source of the PMOS transistor, and the third end of the switching unit is the gate of the PMOS transistor; The first end of the voltage dividing circuit is connected to the source of the PMOS transistor, the second end of the voltage dividing circuit is connected to the gate of the PMOS transistor, and the third end of the voltage dividing circuit is grounded.

[0009] In one embodiment, the voltage dividing circuit includes a second resistor and a third resistor. The first end of the voltage dividing circuit is the first end of the second resistor, the second end of the second resistor is connected to the first end of the third resistor, the second end of the voltage dividing circuit is the voltage dividing point between the second resistor and the third resistor, and the third end of the voltage dividing circuit is the second end of the third resistor.

[0010] In one embodiment, the DC power supply surge protection circuit further includes a first capacitor; The first end of the first capacitor is connected to the DC power supply input interface, and the second end of the first capacitor is grounded.

[0011] In one embodiment, the DC power supply surge protection circuit further includes a second capacitor; The first end of the second capacitor is connected to the first end of the switching unit, and the second end of the second capacitor is grounded.

[0012] In one embodiment, the inductance value of the inductor is lower than a first preset threshold, the volume of the inductor is smaller than a second preset threshold, and the cost of the inductor is smaller than a third preset threshold.

[0013] In one embodiment, the inductor is used to generate a pressure difference when a surge occurs to trigger the conduction of the pressure difference trigger unit.

[0014] In one embodiment, when the pressure difference trigger unit conducts, it triggers the switching unit to turn off to cut off the power supply path between the DC power supply input interface and the subsequent circuit.

[0015] In addition, to achieve the above object, the present application provides a DC power supply surge protection device, and the DC power supply surge protection device includes the DC power supply surge protection circuit as described in any one of the above.

[0016] The DC power supply surge protection circuit proposed in this application is arranged between the DC power supply input interface and the subsequent circuit. The DC power supply surge protection circuit includes an inductor, a differential pressure trigger unit, and a switch unit. The first end of the inductor is connected to the DC power supply input interface, and the second end of the inductor is connected to the subsequent circuit through the switch unit. The first end of the switch unit is connected to the second end of the inductor, the second end of the switch unit is connected to the subsequent circuit, and the third end of the switch unit is connected to the third end of the differential pressure trigger unit. The first end of the differential pressure trigger unit is connected to the DC power supply input interface, and the second end of the differential pressure trigger unit is connected to the first end of the switch unit.

[0017] The DC power supply surge protection circuit proposed in this application, through the collaborative work of the inductor, the differential pressure trigger unit, and the switch unit, when facing the problem of sudden drop in the DCIN voltage caused by a negative pressure surge, the inductor can hinder the sudden change of current. Thus, when the positive voltage of DCIN drops suddenly, the voltage after the inductor still maintains at the normal voltage. At this time, an obvious pressure difference is generated instantaneously across the inductor, triggering the differential pressure trigger unit to conduct, and then triggering the switch unit to turn off, so that the subsequent circuit connected to the switch unit is not affected, avoiding the shutdown or restart phenomenon of the subsequent connected products due to the voltage drop. Thus, the efficient suppression of the surge voltage is achieved, and at the same time, the cost is reduced compared with using a surge protection chip, achieving the effect of protecting against large-power DCIN negative pressure surges at a lower cost. Description of the Drawings

[0018] The drawings here are incorporated into the specification and form a part of this specification, showing embodiments consistent with this application, and are used together with the specification to explain the principles of this application.

[0019] In order to more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0020] Figure 1 It is a schematic diagram of the circuit connection of the embodiment of the DC power supply surge protection circuit of this application; Figure 2 It is another circuit schematic diagram of the embodiment of the DC power supply surge protection circuit of this application.

[0021] Figures 1 to 2 Explanation of the reference numerals in the drawings:

[0022] The realization of the purpose, functional features, and advantages of this application will be further described in combination with the embodiments with reference to the drawings. Detailed implementation manners

[0023] It should be understood that the specific embodiments described herein are only used to explain the technical solutions of the present application and are not used to limit the present application.

[0024] In a DC power supply system, a negative voltage surge will cause a sudden drop in the DCIN voltage, which in turn will cause problems such as shutdown / restart of the products connected to the subsequent stage.

[0025] There are two types of traditional negative voltage surge protection means: connecting a diode in series on the DCIN and adding a surge protection chip to the DCIN circuit. However, in actual applications, the method of connecting a diode in series will cause obvious power loss and is not suitable for high-power scenarios, while the method of adding a surge protection chip has the problem of high cost and difficulty in popularization.

[0026] In summary, how to achieve high-power DCIN negative voltage surge protection at a low cost has become an urgent technical problem in this field.

[0027] An embodiment of the present application provides a solution, and proposes a DC power supply surge protection circuit. The DC power supply surge protection circuit is arranged between the DC power input interface DCIN+ and the subsequent stage circuit VCCIN. The DC power supply surge protection circuit includes an inductor L1, a differential pressure trigger unit 10, and a switch unit 20; the first end of the inductor L1 is connected to the DC power input interface DCIN+, and the second end of the inductor L1 is connected to the subsequent stage circuit VCCIN through the switch unit 20; the first end of the switch unit 20 is connected to the second end of the inductor L1, the second end of the switch unit 20 is connected to the subsequent stage circuit VCCIN, and the third end of the switch unit 20 is connected to the third end of the differential pressure trigger unit 10; the first end of the differential pressure trigger unit 10 is connected to the DC power input interface DCIN+, and the second end of the differential pressure trigger unit 10 is connected to the first end of the switch unit 20.

[0028] In summary, it can be seen that the DC power supply surge protection circuit proposed in the embodiment of the present application, through the coordinated operation of the inductor L1, the differential pressure trigger unit 10, and the switch unit 20, when facing the problem of sudden drop in the DCIN voltage caused by a negative voltage surge, the inductor L1 can prevent the sudden change of current. Therefore, when the positive voltage of the DCIN drops suddenly, the voltage after the inductor L1 still maintains the normal voltage. At this time, an obvious differential pressure is generated across the inductor L1 instantaneously, triggering the differential pressure trigger unit 10 to conduct, and then triggering the switch unit 20 to close, so that the subsequent stage circuit VCCIN connected to the switch unit 20 is not affected, avoiding the shutdown or restart phenomenon of the products connected to the subsequent stage due to voltage reduction. Thus, the efficient suppression of the surge voltage is achieved, and at the same time, the cost is reduced compared with using a surge protection chip, achieving the effect of realizing high-power DCIN negative voltage surge protection at a low cost.

[0029] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. If there are descriptions such as "first", "second", etc. in the embodiments of the present application, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features.

[0030] This embodiment proposes a DC power supply surge protection circuit, aiming to achieve high-power DCIN negative voltage surge protection at a relatively low cost.

[0031] Please refer to Figure 1 , Figure 1 which is a schematic circuit diagram of the first embodiment of the DC power supply surge protection circuit of the present application.

[0032] In this embodiment, the DC power supply surge protection circuit is arranged between the DC power supply input interface DCIN+ and the subsequent circuit VCCIN. The DC power supply surge protection circuit includes an inductor L1, a differential pressure trigger unit 10, and a switch unit 20; The first end of the inductor L1 is connected to the DC power supply input interface DCIN+, and the second end of the inductor L1 is connected to the subsequent circuit VCCIN through the switch unit 20; In this embodiment, the first end of the inductor L1 is connected to the DC power supply input interface DCIN+, and the second end of the inductor L1 is connected to the subsequent circuit VCCIN through the switch unit 20, forming a current transmission path.

[0033] The first end of the switch unit 20 is connected to the second end of the inductor L1, the second end of the switch unit 20 is connected to the subsequent circuit VCCIN, and the third end of the switch unit 20 is connected to the third end of the differential pressure trigger unit 10; In this embodiment, the first end of the switch unit 20 is connected to the second end of the inductor L1 to receive the current signal from the inductor L1. The second end of the switch unit 20 is connected to the subsequent circuit VCCIN to transmit the current to the load of the subsequent circuit. The third end of the switch unit 20 is connected to the third end of the differential pressure trigger unit 10 to form an interaction path for the control signal, ensuring that the circuit can respond quickly and cut off under specific conditions.

[0034] It is worth mentioning that under normal circumstances, the switch unit 20 remains in the conducting state to ensure the smooth transmission of current to the subsequent circuit VCCIN. When there is a problem of sudden voltage drop caused by a negative voltage surge, the switch unit 20 quickly cuts off the circuit to protect the subsequent circuit VCCIN from damage.

[0035] The first end of the differential pressure trigger unit 10 is connected to the DC power input interface DCIN+, and the second end of the differential pressure trigger unit 10 is connected to the first end of the switch unit 20.

[0036] In this embodiment, the differential pressure trigger unit 10 is responsible for monitoring the voltage change across the inductor L1. Its first end is connected to the DC power input interface DCIN+ to sense the fluctuation of the input voltage in real time. Its second end is connected to the first end of the switch unit 20. By comparing the difference between the input voltage and the voltage at the switch unit 20, it determines whether a protection action needs to be triggered. When an abnormal voltage difference is detected, the differential pressure trigger unit 10 will quickly send a control signal to the switch unit 20 to prompt it to cut off the circuit, thereby protecting the subsequent circuit VCCIN from surge voltage damage.

[0037] In a feasible embodiment, as Figure 2 shown, the differential pressure trigger unit 10 includes a first resistor R1 and a triode Q1. The first end of the differential pressure trigger unit 10 is the first end of the first resistor R1, the second end of the differential pressure trigger unit 10 is the emitter of the triode Q1, and the third end of the differential pressure trigger unit 10 is the collector of the triode Q1; The second end of the first resistor R1 is connected to the base of the triode Q1.

[0038] In this embodiment, the differential pressure trigger unit 10 includes a first resistor R1 and a triode Q1. It should be noted that the triode Q1 in this embodiment is specifically a PNP triode. On this basis, the first end of the first resistor R1 is connected to the DC power input interface DCIN+; the second end of the first resistor R1 is connected to the base of the triode Q1 (i.e., Figure 2 B in Figure 2 ); the emitter of the triode Q1 (i.e., Figure 2 E in

[0039] is connected to the first end of the switch unit 20; the collector of the triode (i.e., Figure 2 C in

[0039] is connected to the third end of the switching power supply.

[0039] Among them, the first resistor R1 plays a role of voltage division and current limiting in the differential pressure trigger unit 10. It is connected between the positive pole of DCIN and the base of the triode Q1. Through the voltage division effect, a part of the input voltage is introduced to the base of the triode Q1, thereby controlling the conduction state of the triode Q1. At the same time, the first resistor R1 also limits the current flowing into the base of the triode Q1 to prevent the triode Q1 from being damaged due to excessive current.

[0040] The first resistor R1 and the triode Q1 together constitute the differential pressure trigger unit 10. By monitoring the voltage difference between DCIN and the first end of the switch unit 20 in real time, that is, the voltage difference across the inductor L1, and controlling the conduction state of the triode Q1 according to the change of the voltage difference, a corresponding control signal is sent to the switch unit 20 to effectively protect the subsequent circuit VCCIN.

[0041] In a feasible embodiment, the switching unit 20 includes a PMOS transistor Q2 and a voltage dividing circuit. The first terminal of the switching unit 20 is the drain of the PMOS transistor Q2, the second terminal of the switching unit 20 is the source of the PMOS transistor Q2, and the third terminal of the switching unit 20 is the gate of the PMOS transistor Q2; The first terminal of the voltage dividing circuit is connected to the source of the PMOS transistor Q2 (i.e., Figure 2 S in Figure 2 ), the second terminal of the voltage dividing circuit is connected to the gate of the PMOS transistor Q2 (i.e.,

[0042] G in Figure 2 ), and the third terminal of the voltage dividing circuit is grounded.

[0043] In this embodiment, the switching unit 20 includes a PMOS transistor Q2 and a voltage dividing circuit. On this basis, the drain of the PMOS transistor Q2 (i.e.,

[0044] D in

[0045]

[0046] In a feasible embodiment, the voltage dividing circuit includes a second resistor R2 and a third resistor R3. The first terminal of the voltage dividing circuit is the first terminal of the second resistor R2, the second terminal of the second resistor R2 is connected to the first terminal of the third resistor R3, the second terminal of the voltage dividing circuit is the voltage dividing point VG1 between the second resistor R2 and the third resistor R3, and the third terminal of the voltage dividing circuit is the second terminal of the third resistor R3.

[0047] In this embodiment, the voltage dividing circuit includes a second resistor R2 and a third resistor R3. On this basis, the first end of the second resistor R2 is connected to the source electrode of the PMOS transistor Q2, the second end of the second resistor R2 is connected to the first end of the third resistor R3, the second end of the third resistor R3 is grounded, and the voltage dividing point VG1 between the second end of the second resistor R2 and the first end of the third resistor R3 is connected to the gate of the PMOS transistor Q2.

[0048] Among them, the resistance values of the second resistor R2 and the third resistor R3 directly affect the voltage level of the voltage dividing point VG1. By adjusting the resistance value of the second resistor R2 and / or the third resistor R3, the proportional relationship between the voltage of the voltage dividing point VG1 and the source voltage can be changed, providing a stable voltage division voltage for the gate of the PMOS transistor Q2, ensuring that the PMOS transistor Q2 can work accurately and reliably, and realizing effective protection for the subsequent stage circuit VCCIN.

[0049] In a feasible embodiment, the DC power supply surge protection circuit further includes a first capacitor C1; The first end of the first capacitor C1 is connected to the DC power supply input interface DCIN+, and the second end of the first capacitor C1 is grounded.

[0050] In this embodiment, the first capacitor C1 is connected between the DC power supply input interface DCIN+ and the ground, playing a role in filtering and stabilizing the voltage. It can absorb the transient voltage fluctuations and high-frequency noises at the power supply input end, reduce the influence of these interferences on the subsequent stage circuit VCCIN. At the same time, the first capacitor C1 can also provide short-term energy storage at the power supply input end to cope with sudden current demands and ensure the stable operation of the circuit.

[0051] In a feasible embodiment, the DC power supply surge protection circuit further includes a second capacitor C2; The first end of the second capacitor C2 is connected to the first end of the switch unit 20, and the second end of the second capacitor C2 is grounded.

[0052] In this embodiment, the second capacitor C2 is connected between the first end of the switch unit 20 (i.e., the drain of the PMOS transistor Q2) and the ground, playing a role in filtering and energy storage. The second capacitor C2 can absorb the voltage fluctuations and noises at the input end of the switch unit 20, ensuring that the PMOS transistor Q2 can work smoothly during the on and off processes. In addition, the second capacitor C2 can also provide additional current support when the switch unit 20 switches between connection and disconnection, reducing voltage dips and spikes, and protecting the subsequent stage circuit VCCIN from surge voltages.

[0053] The addition of the first capacitor C1 and the second capacitor C2 further enhances the performance and stability of the DC power supply surge protection circuit. Through filtering, energy storage, and voltage stabilization, they effectively reduce the interference and fluctuations at the power input terminal and the input terminal of the switching unit 20, ensuring that the circuit can operate reliably under various working conditions and providing a more stable and safe power supply environment for the subsequent-stage circuit VCCIN.

[0054] In a feasible embodiment, the inductance value of the inductor L1 is lower than the first preset threshold, and the volume of the inductor is smaller than the second preset threshold, and the cost of the inductor is less than the third preset threshold.

[0055] In this embodiment, the inductor L1 is an inductor with an inductance value lower than the first preset threshold, a volume smaller than the second preset threshold, and a cost less than the third preset threshold. Among them, the magnitudes of the first preset threshold, the second preset threshold, and the third preset threshold can be set based on the actual application scenario, and no specific limitation is made in this embodiment.

[0056] In high-power scenarios, the device often has a large current transient, and the inductor L1 will impede the current change. If the inductance value is too large, it will cause DCIN to be unable to supply sufficient transient current to the subsequent-stage circuit VCCIN, affecting the normal operation of the device. In this embodiment, because the DCIN surge voltage changes very quickly, a sufficient voltage drop for the PNP transistor Q1 to conduct can be generated on the inductor L1 with a very small inductance value; the inductor L1 with a small inductance value has a weak current suppression ability and has almost no impact when the subsequent stage requires a large transient current. Moreover, in the case of the same current-carrying capacity, the inductor L1 with a small inductance value has the advantages of small size, low impedance, and low cost.

[0057] In a feasible embodiment, the inductor L1 is used to generate a pressure difference during a surge to trigger the pressure-difference trigger unit 10 to conduct.

[0058] In this embodiment, when the surge voltage appears, the inductor L1 will generate a pressure difference across its two ends due to its own characteristics. The magnitude of this pressure difference depends on the amplitude of the surge voltage and the inductance value of the inductor L1. By reasonably setting the inductance value, it can be ensured that the pressure difference generated during a surge is sufficient to trigger the pressure-difference trigger unit 10 to conduct.

[0059] In a feasible embodiment, when the pressure-difference trigger unit 10 conducts, the trigger switch unit 20 is turned off to cut off the power supply path between the DC power input interface DCIN+ and the subsequent-stage circuit VCCIN.

[0060] In this embodiment, after the differential pressure trigger unit 10 receives the differential pressure signal generated by the inductor L1, it will conduct rapidly, that is, the emitter and collector of the triode Q1 conduct. Under the condition that the differential pressure trigger unit 10 conducts, there is no differential pressure between the gate and source of the PMOS transistor Q2, so the switch unit 20 will close rapidly, cutting off the power supply path between the DC power input interface DCIN+ and the subsequent circuit VCCIN, thus effectively isolating the influence of the surge voltage on the subsequent circuit VCCIN and preventing the subsequent circuit VCCIN from being damaged by the surge voltage.

[0061] In summary, in this embodiment, the setting of the inductance value of the inductor L1, the generation of differential pressure during surge occurrence, the conduction of the differential pressure trigger unit 10, and the closing of the switch unit 20 and other links together constitute the core protection mechanism of the DC power supply surge protection circuit. Through the collaborative work of each unit, it ensures that the circuit can respond quickly and effectively when facing the surge voltage and protects the subsequent circuit VCCIN from damage.

[0062] In addition, this embodiment also provides a DC power supply surge protection device, and the DC power supply surge protection device includes the DC power supply surge protection circuit as described in any one of the above.

[0063] The above are only optional embodiments of the present application, and do not limit the patent scope of the present application. Any equivalent structural transformation made by using the content of the specification and drawings of the present application under the application concept of the present application, or direct / indirect application in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A DC power surge protection circuit, characterized in that, The DC power supply surge protection circuit is arranged between the DC power supply input interface and the subsequent stage circuit. The DC power supply surge protection circuit includes an inductor, a voltage difference trigger unit, and a switch unit; The first end of the inductor is connected to the DC power supply input interface, and the second end of the inductor is connected to the subsequent stage circuit through the switch unit; The first end of the switch unit is connected to the second end of the inductor, the second end of the switch unit is connected to the subsequent stage circuit, and the third end of the switch unit is connected to the third end of the voltage difference trigger unit; The first end of the voltage difference trigger unit is connected to the DC power supply input interface, and the second end of the voltage difference trigger unit is connected to the first end of the switch unit.

2. The DC power supply surge protection circuit according to claim 1, wherein, The voltage difference trigger unit includes a first resistor and a triode. The first end of the voltage difference trigger unit is the first end of the first resistor, the second end of the voltage difference trigger unit is the emitter of the triode, and the third end of the voltage difference trigger unit is the collector of the triode; The second end of the first resistor is connected to the base of the triode.

3. The DC power surge protection circuit according to claim 1, characterized in that, The switch unit includes a PMOS transistor and a voltage dividing circuit. The first end of the switch unit is the drain of the PMOS transistor, the second end of the switch unit is the source of the PMOS transistor, and the third end of the switch unit is the gate of the PMOS transistor; The first end of the voltage dividing circuit is connected to the source of the PMOS transistor, the second end of the voltage dividing circuit is connected to the gate of the PMOS transistor, and the third end of the voltage dividing circuit is grounded.

4. The DC power surge protection circuit according to claim 3, wherein The voltage dividing circuit includes a second resistor and a third resistor. The first end of the voltage dividing circuit is the first end of the second resistor, the second end of the second resistor is connected to the first end of the third resistor, the second end of the voltage dividing circuit is the voltage dividing point between the second resistor and the third resistor, and the third end of the voltage dividing circuit is the second end of the third resistor.

5. The DC power surge protection circuit according to claim 1, characterized in that, The DC power supply surge protection circuit further includes a first capacitor; The first end of the first capacitor is connected to the DC power supply input interface, and the second end of the first capacitor is grounded.

6. The DC power surge protection circuit according to claim 1, characterized in that, The DC power supply surge protection circuit further includes a second capacitor; The first end of the second capacitor is connected to the first end of the switch unit, and the second end of the second capacitor is grounded.

7. The DC power supply surge protection circuit according to claim 1, wherein, The inductance value of the inductor is lower than a first preset threshold, and the volume of the inductor is smaller than a second preset threshold, and the cost of the inductor is less than a third preset threshold.

8. The DC power supply surge protection circuit according to claim 1, wherein, The inductor is used to generate a voltage difference during a surge to trigger the conduction of the voltage difference trigger unit.

9. The DC power surge protection circuit according to claim 8, wherein When the voltage difference trigger unit conducts, it triggers the switch unit to turn off to cut off the power supply path between the DC power supply input interface and the subsequent stage circuit.

10. A DC power supply surge protection device, characterized in that, The DC power supply surge protection device includes the DC power supply surge protection circuit according to any one of claims 1 to 9.

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