Power supply protection circuit and power supply module

Abstract

The utility model discloses a power supply protection circuit and a power supply module, an overcurrent protection circuit is used to detect the current of a power supply, a switch circuit is controlled to disconnect the conduction relation between the power supply and a power supply output interface according to the detection result, and a voltage detection circuit is used to detect the voltage of the power supply output interface. And the controller disconnects the conduction relation between the power supply and the power supply output interface through the switching circuit according to the detection result of the voltage detection circuit, so that overcurrent protection and overvoltage protection of the power supply output are realized, the reliability and safety of the power supply output are improved, and the service life of the power supply output is prolonged.

Description

Technical Field

[0001] The utility model relates to a power supply, in particular to a power supply protection circuit and a power supply module. Background Art

[0002] The existing power output circuit usually controls the conduction state of the switch element through a controller, thereby conducting the power supply circuit between the power supply and the external device through the switch element to realize the power supply output of the external device.

[0003] However, a large current may easily occur in the above power output circuit, causing the switch element or the power supply to burn out, and the safety is low. Utility Model Content

[0004] The purpose of the utility model is to overcome the shortcomings and deficiencies of the prior art and to provide a power protection circuit and a power module with high safety and high reliability.

[0005] In the first aspect, the utility model provides a power supply protection circuit, including a controller, a voltage detection circuit, an overcurrent protection circuit and a switching circuit; the voltage detection circuit is used to detect the voltage of the power supply output interface, the voltage detection circuit is connected to the controller, and the overcurrent protection circuit is connected to the power supply; the first end of the switching circuit is connected to the power supply, and the second end of the switching circuit is connected to the power supply output interface; the control end of the switching circuit is respectively connected to the overcurrent protection circuit and the controller.

[0006] Optionally, the voltage detection circuit includes a first voltage-dividing resistor and a second voltage-dividing resistor, the first end of the first voltage-dividing resistor is connected to the power supply output interface, the second end of the first voltage-dividing resistor is respectively connected to the first end of the second voltage-dividing resistor and the controller, and the second end of the second voltage-dividing resistor is grounded.

[0007] In the embodiment of the present application, a voltage-dividing circuit is formed by utilizing a first voltage-dividing resistor and a second voltage-dividing resistor. The controller realizes real-time detection of the power supply output voltage by detecting the voltage after voltage division by the voltage-dividing circuit, and promptly disconnects the loop between the power supply and the power supply output interface by controlling the switching circuit when the output voltage exceeds the target voltage threshold, thereby realizing overvoltage protection for the power supply output, avoiding excessive power supply output voltage from damaging the controller, and improving the reliability of the circuit.

[0008] Optionally, the overcurrent protection circuit includes a first resistor, a second resistor, a third resistor and a first transistor.

[0009] The base of the first transistor is connected to the first end of the second resistor, the second end of the second resistor is connected to the second end of the first resistor, the first end of the first resistor is connected to a power supply, the emitter of the transistor is connected to the ground and the first end of the third resistor respectively, and the collector of the transistor is connected to the switching circuit and the second end of the third resistor respectively.

[0010] By using the first resistor, the second resistor and the third resistor to adjust the voltage output to the emitter and the base of the first transistor, the on and off control of the switch circuit is achieved by controlling the on and off of the first transistor, thereby turning on or off the loop between the power supply and the power supply output interface to achieve overcurrent protection of the power supply output. Compared with the prior art, the circuit structure of the present application is simple, does not involve multi-stage circuits, can quickly realize current detection and overcurrent protection, and improves the efficiency of overcurrent protection and the reliability of power supply output.

[0011] Optionally, the overcurrent protection circuit further includes a fourth resistor connected in parallel with the first resistor.

[0012] By arranging a fourth resistor in parallel at both ends of the first resistor, under the condition of the same input voltage, the resistance value is reduced by the fourth resistor, thereby increasing the power of the overcurrent protection circuit and further improving the reliability of the circuit.

[0013] Optionally, the switch circuit includes a fifth resistor, a sixth resistor, a second transistor and a third transistor;

[0014] The base of the second transistor is connected to the controller through a fifth resistor, the emitter of the second transistor is grounded, the collector of the second transistor is connected to the base of the third transistor through a sixth resistor, the emitter of the third transistor is connected to the power supply, and the collector of the third transistor is connected to the power supply output interface.

[0015] In the embodiment of the present application, the loop between the power supply and the power supply output interface is disconnected in time by controlling the on and off of the second transistor and the third transistor. The second transistor and the third transistor can achieve nanosecond response, and the switching circuit has a fast response speed. At the same time, the switching circuit of the present application has a simple structure and low cost.

[0016] Optionally, the switch circuit further includes a first filter capacitor, a first end of the first filter capacitor is connected to the base of the second transistor, and a second end of the first filter capacitor is grounded.

[0017] The first filter capacitor is used to filter the signal output to the base of the second transistor, thereby improving the stability of the signal output from the controller to the base of the second transistor.

[0018] Optionally, the switch circuit further includes a pull-down resistor, and the base of the second transistor is grounded through the pull-down resistor.

[0019] The present application improves the stability and reliability of triggering the second transistor by setting a pull-down resistor at the base of the second transistor.

[0020] Optionally, a second filter capacitor is further included, and the power supply is grounded through the second filter capacitor.

[0021] The present application utilizes a second filter capacitor to filter the power signal of the power input, thereby reducing the interference of the power signal on the circuit elements and improving the stability of the circuit.

[0022] Optionally, a third filter capacitor is further included, and the power supply output interface is grounded through the third filter capacitor.

[0023] The present application improves the stability and reliability of the output power signal by using a third filter capacitor to filter the power signal output by the power supply output interface.

[0024] In the second aspect, the utility model provides a power supply module, comprising a power supply, a power supply output interface and a power supply protection circuit as described in any of the above items; the power supply is respectively connected to the first end of the overcurrent protection circuit and the switching circuit, and the power supply output interface is respectively connected to the second end of the voltage detection circuit and the switching circuit.

[0025] In an embodiment of the present application, an overcurrent protection circuit is used to detect the current of the power supply, and the switch circuit is controlled to disconnect the conduction relationship between the power supply and the power supply output interface according to the detection result. The voltage of the power supply output interface is detected by a voltage detection circuit. The controller disconnects the conduction relationship between the power supply and the power supply output interface through a switch circuit according to the detection result of the voltage detection circuit, thereby realizing overcurrent protection and overvoltage protection for the power supply output, and improving the reliability, safety and service life of the power supply output.

[0026] In order to better understand and implement the present invention, the present invention is described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of an existing power protection circuit;

[0028] Figure 2 It is a schematic diagram of the structure of a power protection circuit in one embodiment of the utility model;

[0029] Figure 3 is a circuit diagram of a voltage detection circuit in one embodiment of the utility model;

[0030] Figure 4is a circuit diagram of a power protection circuit in another embodiment of the utility model;

[0031] Figure 5 It is a structural schematic diagram of a power module in one embodiment of the utility model. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the present application clearer, the present invention will be further described in detail below with reference to the accompanying drawings.

[0033] It should be clear that the described embodiments are only part of the embodiments of the utility model, not all of them. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0034] The terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The singular forms "a", "the" and "the" used in the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0035] When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the attached claims. In the description of the present application, it should be understood that the terms "first", "second", "third", etc. are only used to distinguish similar objects, and do not have to be used to describe a specific order or sequence, nor can they be understood as indicating or implying relative importance. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0036] In addition, in the description of this application, unless otherwise specified, "several" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the associated objects are in an "or" relationship.

[0037] The power output circuit is used to output a power signal to an external device, thereby providing power to the external device.

[0038] See also Figure 1, which is a circuit diagram of a power output circuit in an existing embodiment. Figure 1 As shown, the power output circuit is directly controlled by the controller to control the conduction of the transistor Q1 to output the 5V power signal to the external device through the output interface.

[0039] However, in the above circuit, when the output interface is short-circuited to the ground, 5V voltage is directly applied to both ends of the transistor Q1, and the transistor Q1 cannot withstand the large current and burns out directly; after the transistor Q1 burns out, it may present three states: open circuit, short circuit and short circuit between base and collector.

[0040] When transistor Q1 is open, there is no power signal output from the output interface;

[0041] When transistor Q1 is short-circuited, the power supply is short-circuited to ground, causing the power supply to burn out and affecting the safety of the circuit;

[0042] When the base and collector of transistor Q1 are short-circuited, the power supply is directly connected to the controller, which may easily cause the controller to break down and burn out.

[0043] When the output interface is short-circuited to an external power supply or other high-voltage input, the reverse high voltage is directly applied to both ends of the transistor Q1, which may easily cause the transistor Q1 to burn out; after the transistor Q1 burns out, it may present three states: open circuit, short circuit, base and collector short circuit, or base and emitter short circuit.

[0044] When transistor Q1 is open, there is no power signal output from the output interface;

[0045] When transistor Q1 is short-circuited, the 5V power supply is connected to an external power supply or other high-voltage input, which can easily cause the power supply or circuit to burn out, affecting circuit safety;

[0046] When the base and collector of transistor Q1 are short-circuited, the power supply is directly connected to the controller, which may easily cause the controller to break down and burn out.

[0047] When the base and emitter of transistor Q1 are short-circuited, the external power supply or other high-voltage input is directly connected to the controller, which can easily cause the controller to break down and burn out.

[0048] It can be seen that the existing power output circuit is prone to damage to the transistor, power supply and current when the output interface is abnormal, affecting the safety of the power output circuit.

[0049] Therefore, in response to the above problems, an embodiment of the present application proposes a power supply protection circuit, which utilizes an overcurrent protection circuit to detect the current of the power supply, controls the switch circuit to disconnect the conduction relationship between the power supply and the power supply output interface according to the detection result, utilizes the voltage detection circuit to detect the voltage of the power supply output interface, and the controller disconnects the conduction relationship between the power supply and the power supply output interface through the switch circuit according to the detection result of the voltage detection circuit, thereby realizing overcurrent protection and overvoltage protection for the power supply output, and improving the reliability, safety and service life of the power supply output.

[0050] like Figure 2 As shown, the utility model provides a power protection circuit, including a controller 110, a voltage detection circuit 120, an overcurrent protection circuit 130 and a switch circuit 140;

[0051] The voltage detection circuit 120 is connected to the controller 110;

[0052] The controller 110 is used to control the on and off of the switch circuit 140, thereby controlling the conduction relationship between the power supply and the power supply output interface. Specifically, when the controller 110 detects that the voltage exceeds the target voltage threshold, the switch circuit 140 is controlled to disconnect the conduction relationship between the power supply and the power supply output interface, thereby realizing overvoltage protection for the power supply output.

[0053] The voltage detection circuit 120 is connected to the power supply output interface and is used to detect the voltage of the power supply output interface.

[0054] The overcurrent protection circuit 130 is used to detect the current of the power supply, and control the on and off of the switch circuit 140 according to the detection result, thereby controlling the conduction relationship between the power supply and the power supply output interface. Specifically, when the overcurrent protection circuit 130 detects that the current exceeds the target current threshold, the switch circuit 140 is controlled to disconnect the conduction relationship between the power supply and the power supply output interface, thereby realizing overcurrent protection of the power supply output.

[0055] The first end of the switch circuit 140 is connected to the power supply, and the second end of the switch circuit 140 is connected to the power supply output interface; the control end of the switch circuit 140 is connected to the overcurrent protection circuit 130 and the controller 110 respectively.

[0056] The switch circuit 140 is used to control the conduction relationship between the power supply and the power output interface, thereby controlling the power supply to output a power signal to the power output interface. The switch circuit 140 can use common switch elements such as transistors, switches, and relays to control the conduction relationship between the power supply and the power output interface.

[0057] Specifically, the switch circuit 140 may be a circuit that is turned on at a low level. When the control end of the switch circuit 140 receives a low-level enable signal, the switch circuit 140 is turned on, the loop between the power supply and the power output interface is turned on, and the power supply output interface outputs a power signal. When the control end of the switch circuit 140 receives a high-level enable signal, the switch circuit 140 is turned off, the loop between the power supply and the power output interface is interrupted, and the power output interface does not output a power signal.

[0058] In an embodiment of the present application, an overcurrent protection circuit is used to detect the current of the power supply, and the switch circuit is controlled to disconnect the conduction relationship between the power supply and the power supply output interface according to the detection result. The voltage of the power supply output interface is detected by a voltage detection circuit. The controller disconnects the conduction relationship between the power supply and the power supply output interface through a switch circuit according to the detection result of the voltage detection circuit, thereby realizing overcurrent protection and overvoltage protection for the power supply output, and improving the reliability, safety and service life of the power supply output.

[0059] See also Figure 3 , which is a circuit diagram of a voltage detection circuit in one embodiment; Figure 3 As shown, the voltage detection circuit includes a first voltage-dividing resistor R9 and a second voltage-dividing resistor R10, the first end of the first voltage-dividing resistor R9 is connected to the power supply output interface, the second end of the first voltage-dividing resistor R9 is respectively connected to the first end of the second voltage-dividing resistor R10 and the controller 110, and the second end of the second voltage-dividing resistor R10 is grounded.

[0060] The first voltage-dividing resistor R9 and the second voltage-dividing resistor R10 are used to divide the output voltage. The resistance values ​​of the first voltage-dividing resistor R9 and the second voltage-dividing resistor R10 can be determined according to the output voltage of the power supply, the voltage limit value of the circuit and / or the input voltage range of the controller IO port. For example, in an embodiment of the present application, when the power supply is a 5V DC power supply, the first voltage-dividing resistor R9 can be 39KΩ and the second voltage-dividing resistor R10 can be 10KΩ.

[0061] Optionally, the voltage detection circuit may further include a filter capacitor C4, a first end of the filter capacitor C4 is connected to the controller 110, and a second end of the filter capacitor C4 is grounded. The filter capacitor C4 is used to filter the detection signal of the voltage detection circuit 120, thereby reducing noise interference during signal transmission and improving the accuracy of voltage detection.

[0062] The controller 110 controls the switch circuit and the conduction relationship between the power supply and the power output interface by detecting the divided voltage. Specifically, when the controller 110 detects that the voltage value exceeds 3.2V, the switch circuit 140 is controlled to disconnect the conduction relationship between the power supply and the power output interface.

[0063] In the embodiment of the present application, a voltage-dividing circuit is formed by utilizing a first voltage-dividing resistor and a second voltage-dividing resistor. The controller realizes real-time detection of the power supply output voltage by detecting the voltage after voltage division by the voltage-dividing circuit, and promptly disconnects the loop between the power supply and the power supply output interface by controlling the switching circuit when the output voltage exceeds the target voltage threshold, thereby realizing overvoltage protection for the power supply output, avoiding excessive power supply output voltage from damaging the controller, and improving the reliability of the circuit.

[0064] The existing overcurrent protection circuit usually realizes the current overcurrent protection by setting a current detection circuit and an amplifier circuit, using the amplifier circuit to amplify the current detected by the current detection circuit, and then the controller controls the on-off of the circuit according to the amplified current value. However, the above circuit detection requires the current detection circuit to detect and the amplifier circuit to amplify before the controller performs calculation and detection. The detection time increases with the increase of the circuit levels, and the detection speed is slow.

[0065] Therefore, in response to the above problems, Figure 4 As shown, in one embodiment, the overcurrent protection circuit includes a first resistor R1, a second resistor R3, a third resistor R5 and a first transistor Q2.

[0066] The base of the first transistor Q2 is connected to the first end of the second resistor R3, the second end of the second resistor R3 is connected to the second end of the first resistor R1, the first end of the first resistor R1 is connected to the power supply, the emitter of the first transistor Q2 is connected to the ground and the first end of the third resistor R5 respectively, the collector of the first transistor Q2 is connected to the switch circuit 140 and the second end of the third resistor R5 respectively,

[0067] The second resistor R3 is a current limiting resistor, which is used to limit the current input to the first transistor Q2, so as to protect the first transistor Q2.

[0068] The target current threshold can be determined according to a specific circuit, for example, in the present application, the target current threshold can be 130 mA. The resistance values ​​of the first resistor R1, the second resistor R3, and the third resistor R5 can be determined according to the target current threshold.

[0069] In the present application, the control end of the switch circuit 140 can be turned on at a low level, that is, the control end of the switch circuit 140 is turned on when it receives a low level signal. When the current of the power supply is greater than the target current threshold, the voltage difference between the emitter and the base of the first transistor Q2 reaches the turn-on voltage of the first transistor Q2, and the first transistor Q2 is turned on. The control end of the switch circuit 140 is connected to the power supply, that is, the control end of the switch circuit 140 receives a high level enable signal. At this time, the switch circuit 140 is cut off, the loop between the power supply and the power supply output interface is interrupted, and the power supply output interface does not output a power signal. Fortunately, overcurrent protection of the power supply output is achieved.

[0070] In the embodiment of the present application, the voltage output to the emitter and base of the first transistor is adjusted by utilizing the first resistor, the second resistor and the third resistor, thereby controlling the on and off of the switching circuit by controlling the on and off of the first transistor, thereby turning on or off the loop between the power supply and the power supply output interface to achieve overcurrent protection of the power supply output. Compared with the prior art, the circuit structure of the present application is simple, does not involve multi-stage circuits, can quickly realize current detection and overcurrent protection, and improves the efficiency of overcurrent protection and the reliability of power supply output.

[0071] like Figure 4 As shown, preferably, the overcurrent protection circuit further includes a fourth resistor R2 connected in parallel with the first resistor R1.

[0072] By providing a fourth resistor R2 in parallel at both ends of the first resistor R1, under the condition of the same input voltage, the resistance value is reduced by the fourth resistor R2, thereby increasing the power of the overcurrent protection circuit and further improving the reliability of the circuit.

[0073] like Figure 4 As shown, in one embodiment, the switch circuit 140 includes a fifth resistor R6, a sixth resistor R4, a second transistor Q3 and a third transistor Q1;

[0074] The base of the second transistor Q3 is connected to the controller through the fifth resistor R6, the emitter of the second transistor Q3 is grounded, the collector of the second transistor Q3 is connected to the base of the third transistor Q1 through the sixth resistor R4, the emitter of the third transistor Q1 is connected to the power supply, and the collector of the third transistor Q1 is connected to the power supply output interface.

[0075] In the present application, the second transistor Q3 is an NPN transistor, and the third transistor Q1 is a PNP transistor. The controller 110 can output high and low level enable signals to the second transistor Q3, thereby controlling the on and off of the third transistor Q1 by controlling the on and off of the second transistor Q3.

[0076] Specifically, when the controller 110 outputs a high-level enable signal to the second transistor Q3, the second transistor Q3 is turned on, the base of the third transistor Q1 is at a low level, the third transistor Q1 is turned on, the loop between the power supply and the power supply output interface is turned on, and the power supply outputs a power signal to the power supply output interface; when the controller 110 outputs a low-level enable signal to the second transistor Q3, the second transistor Q3 is turned off, the base of the third transistor Q1 is at a high level, the third transistor Q1 is turned off, the loop between the power supply and the power supply output interface is interrupted, and the power supply output interface does not output a power signal.

[0077] In the embodiment of the present application, the loop between the power supply and the power supply output interface is disconnected in time by controlling the on and off of the second transistor Q3 and the third transistor Q1. The second transistor Q3 and the third transistor Q1 can achieve nanosecond response, and the switching circuit has a fast response speed. At the same time, the switching circuit of the present application has a simple structure and low cost.

[0078] like Figure 4 As shown, in one embodiment, the switch circuit further includes a first filter capacitor C3, a first end of the first filter capacitor C3 is connected to the base of the second transistor Q3, and a second end of the first filter capacitor C3 is grounded.

[0079] The first filter capacitor C3 is used to filter the signal output to the base of the second transistor Q3, thereby improving the stability of the signal output by the controller 110 to the base of the second transistor Q3 and improving the reliability of the second transistor Q3.

[0080] like Figure 4 As shown, in one embodiment, the switch circuit further includes a pull-down resistor R7, and the base of the second transistor Q3 is grounded through the pull-down resistor R7.

[0081] The pull-down resistor R7 is used to clamp the base of the second transistor Q3 at a low level to prevent the second transistor Q3 from mistakenly identifying the noise during the circuit operation as a high level, thereby causing the second transistor Q3 to be falsely triggered.

[0082] The present application improves the stability and reliability of triggering the second transistor by setting a pull-down resistor at the base of the second transistor Q3.

[0083] like Figure 4 As shown, in one embodiment, the power protection circuit further includes a second filter capacitor C1, and the power supply is grounded through the second filter capacitor C1.

[0084] The second filter capacitor C1 is used to filter the power signal in the input circuit, reduce the interference of the power signal on the circuit elements, and improve the stability of the circuit.

[0085] The present application utilizes a second filter capacitor to filter the power signal of the power input, thereby reducing the interference of the power signal on the circuit elements and improving the stability of the circuit.

[0086] like Figure 4 As shown, in one embodiment, the power protection circuit further includes a third filter capacitor C2, and the power output interface is grounded through the third filter capacitor C2.

[0087] The third filter capacitor C2 is used to filter the power signal output to the power output interface to improve the stability and reliability of the output power signal.

[0088] The present application improves the stability and reliability of the output power signal by using a third filter capacitor to filter the power signal output by the power supply output interface.

[0089] like Figure 5 As shown, the utility model also provides a power supply module 200, including a power supply 210, a power supply output interface 220 and a power supply protection circuit 230 as described in any one of the above items; the power supply 210 is respectively connected to the first end of the overcurrent protection circuit and the switching circuit, and the power supply output interface 220 is respectively connected to the second end of the voltage detection circuit and the switching circuit.

[0090] The present invention is not limited to the above-mentioned embodiments. If various changes or modifications to the present invention do not depart from the spirit and scope of the present invention, and if these changes and modifications fall within the claims of the present invention and the scope of equivalent technologies, the present invention is also intended to include these changes and modifications.

Claims

1. A power protection circuit, characterized in that: It includes a controller, a voltage detection circuit, an overcurrent protection circuit and a switch circuit; the voltage detection circuit is used to detect the voltage of the power supply output interface, the voltage detection circuit is connected to the controller, and the overcurrent protection circuit is connected to the power supply; the first end of the switch circuit is connected to the power supply, and the second end of the switch circuit is connected to the power supply output interface; the control end of the switch circuit is connected to the overcurrent protection circuit and the controller respectively; The voltage detection circuit includes a first voltage-dividing resistor and a second voltage-dividing resistor, wherein a first end of the first voltage-dividing resistor is connected to the power supply output interface, a second end of the first voltage-dividing resistor is respectively connected to a first end of the second voltage-dividing resistor and the controller, and a second end of the second voltage-dividing resistor is grounded; The overcurrent protection circuit comprises a first resistor, a second resistor, a third resistor and a first transistor; The base of the first transistor is connected to the first end of the second resistor, the second end of the second resistor is connected to the second end of the first resistor, the first end of the first resistor is connected to a power supply, the emitter of the transistor is connected to the ground and the first end of the third resistor respectively, and the collector of the transistor is connected to the switch circuit and the second end of the third resistor respectively; The switch circuit includes a fifth resistor, a sixth resistor, a second transistor and a third transistor; The base of the second transistor is connected to the controller through a fifth resistor, the emitter of the second transistor is grounded, the collector of the second transistor is connected to the base of the third transistor through a sixth resistor, the emitter of the third transistor is connected to the power supply, and the collector of the third transistor is connected to the power supply output interface.

2. The power protection circuit according to claim 1, characterized in that: The overcurrent protection circuit further includes a fourth resistor connected in parallel with the first resistor.

3. The power protection circuit according to claim 1, characterized in that: The switch circuit further includes a first filter capacitor, a first end of the first filter capacitor is connected to the base of the second transistor, and a second end of the first filter capacitor is grounded.

4. The power protection circuit according to claim 1, characterized in that: The switch circuit further includes a pull-down resistor, and the base of the second transistor is grounded through the pull-down resistor.

5. The power protection circuit according to claim 1, characterized in that: It also includes a second filter capacitor, and the power supply is grounded through the second filter capacitor.

6. The power protection circuit according to claim 1, characterized in that: It also includes a third filter capacitor, and the power supply output interface is grounded through the third filter capacitor.

7. A power module, characterized in that: It includes a power supply, a power supply output interface and a power supply protection circuit as described in any one of claims 1 to 6; the power supply is respectively connected to the first end of the overcurrent protection circuit and the switching circuit, and the power supply output interface is respectively connected to the second end of the voltage detection circuit and the switching circuit.

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