Protection circuit and electronic equipment

Abstract

The utility model discloses a protection circuit and electronic equipment, and belongs to the technical field of power supply protection. A current detection circuit detects the current of direct current to output a detection signal; the current-limiting protection circuit outputs a first control voltage when the voltage of the detection signal is greater than a first preset voltage; the turn-off circuit outputs a turn-off signal in response to the fact that the voltage of the first node is larger than a second preset voltage, and the voltage of the first node is the difference between the voltage of the direct current and the voltage drop of the load; the switching circuit responds to the turn-off signal to stop transmitting the direct current, and responds to the stop of the turn-off signal to control the constant current output of the direct current according to the first control voltage; a circuit is built only through low-cost discrete devices, and direct current can be output in a constant-current mode when the voltage of a detection signal is larger than a first preset voltage and the voltage of a first node is smaller than a second preset voltage. And when the voltage of the first node is greater than the second preset voltage, direct current transmission is stopped, so that the safety of the circuit is ensured at low cost, and the applicability of the circuit is improved.

Description

Technical Field

[0001] The present application belongs to the technical field of power supply protection, and in particular, relates to a protection circuit and an electronic device. Background Art

[0002] Generally, when designing a power supply circuit, it is necessary to set a protection function. The total output current limit point can be set through the power supply chip, but the cost of the power supply chip is usually high, which has a greater impact on the circuit cost.

[0003] In addition, existing power supply circuits are usually equipped with a short-circuit shutdown protection function, but the output current limit point and the shutdown point are the same value, which limits its applicable scenarios. For example, when the load is a motor, the current at the moment of startup may briefly and slightly exceed the limit value, but in this scenario, it is not desirable for the motor to be powered off directly, but the motor needs to be able to obtain a certain amount of power to maintain its operation. Only when the load far exceeds the output capacity of the power supply, such as a short circuit fault, is it necessary to completely shut down the output to protect the power supply.

[0004] Therefore, the existing power supply protection circuit has high cost and low applicability. Utility Model Content

[0005] The purpose of the present application is to provide a protection circuit and an electronic device, aiming to solve the problem of high cost and low applicability of existing power protection circuits.

[0006] An embodiment of the present application provides a protection circuit connected to a load at a first node, the protection circuit comprising:

[0007] A current detection circuit configured to detect the current of the direct current to output a detection signal;

[0008] a current limiting protection circuit connected to the current detection circuit and configured to output a first control voltage in response to the voltage of the detection signal being greater than a first preset voltage;

[0009] a shutdown circuit connected to the first node and the current limiting protection circuit, and configured to output a shutdown signal in response to a voltage at the first node being greater than a second preset voltage, wherein the voltage at the first node is a difference between a voltage of the direct current and a voltage drop of the load;

[0010] The switching circuit is connected to the first node, the current detection circuit, the current limiting protection circuit and the shutdown circuit, and is configured to stop transmitting the direct current in response to the shutdown signal, and to control the direct current constant current output according to the first control voltage in response to the stopping of the shutdown signal.

[0011] In one embodiment, the current limiting protection circuit includes:

[0012] A reference circuit configured to output the first preset voltage;

[0013] A comparison circuit is connected to the current detection circuit, the switch circuit, the shutdown circuit and the reference circuit, and is configured to output the first control voltage according to the detection signal and the first preset voltage.

[0014] In one of the embodiments, the current detection circuit includes a first resistor;

[0015] The first end of the first resistor serves as the DC current input end of the current detection circuit and the detection signal output end of the current detection circuit, and is connected to the current limiting protection circuit and the switching circuit to input the DC current and output the detection signal; the second end of the first resistor is connected to the power ground.

[0016] In one embodiment, the reference circuit includes a voltage regulator, a third resistor, a fourth resistor, and a fifth resistor;

[0017] The first end of the third resistor and the first end of the fourth resistor serve together as the first preset voltage output end of the reference circuit, and are connected to the comparison circuit to output the first preset voltage; the second end of the third resistor is connected to the negative electrode of the regulator, the control end of the regulator and the first end of the fifth resistor, the second end of the fifth resistor is connected to the first power supply, and the positive electrode of the regulator and the second end of the fourth resistor are commonly connected to the power ground.

[0018] In one of the embodiments, the comparison circuit includes an operational amplifier and a second resistor;

[0019] The non-inverting input terminal of the operational amplifier serves as the first preset voltage input terminal of the comparison circuit, and is connected to the reference circuit to input the first preset voltage; the inverting input terminal of the operational amplifier serves as the detection signal input terminal of the comparison circuit, and is connected to the current detection circuit and the switch circuit to input the detection signal; the output terminal of the operational amplifier is connected to the first end of the second resistor, and the second end of the second resistor serves as the first control voltage output terminal of the comparison circuit, and is connected to the switch circuit and the shutdown circuit to output the first control voltage.

[0020] In one embodiment, the protection circuit further includes:

[0021] a recovery circuit connected to the first node and configured to connect the direct current to a power ground and sample the current of the direct current to output a sampling signal when the switch circuit stops transmitting the direct current;

[0022] The shutdown circuit is further configured to stop outputting the shutdown signal when the voltage of the sampling signal is less than a second preset voltage.

[0023] In one embodiment, the recovery circuit includes a sixth resistor;

[0024] The first end of the sixth resistor serves as the DC current input end of the recovery circuit and the sampling signal output end of the recovery circuit, and is connected to the first node to input the DC current and output the sampling signal; the second end of the sixth resistor is connected to the power ground.

[0025] In one of the embodiments, the shutdown circuit includes a voltage stabilizing diode and a second switch tube;

[0026] The cathode of the voltage-stabilizing diode serves as the voltage input terminal of the first node of the shutdown circuit and the sampling signal input terminal of the shutdown circuit, and is connected to the first node and the recovery circuit to input the voltage and sampling signal of the first node; the anode of the voltage-stabilizing diode is connected to the control terminal of the second switch tube, and the first terminal of the second switch tube serves as the shutdown signal output terminal of the shutdown circuit, and is connected to the switch circuit and the current limiting protection circuit to output the shutdown signal; the second terminal of the second switch tube is connected to the power ground.

[0027] In one embodiment, the switch circuit includes a first switch tube;

[0028] The first end of the first switch tube serves as a DC input end of the switch circuit and is connected to the first node to receive the DC power; the second end of the first switch tube serves as a DC output end of the switch circuit and is connected to the current detection circuit and the current limiting protection circuit to output the DC power; the control end of the first switch tube serves as a shutdown signal input end of the switch circuit and a first control voltage input end of the switch circuit to input the shutdown signal and the first control voltage.

[0029] An embodiment of the present application further provides an electronic device, which includes the above-mentioned protection circuit.

[0030] Compared with the prior art, the embodiments of the present application have the following beneficial effects: the current detection circuit detects the current of the direct current to output a detection signal; the current limiting protection circuit outputs a first control voltage in response to the voltage of the detection signal being greater than a first preset voltage; the shutdown circuit outputs a shutdown signal in response to the voltage of the first node being greater than a second preset voltage, wherein the voltage of the first node is the difference between the voltage of the direct current and the voltage drop of the load; the switch circuit stops transmitting the direct current in response to the shutdown signal, and controls the direct current constant current output according to the first control voltage in response to the stopping of the shutdown signal, thereby eliminating the need for a power chip, and only requiring the circuit to be built using low-cost discrete devices, so that when the load increases, that is, when the voltage of the detection signal is greater than the first preset voltage and the voltage of the first node is less than the second preset voltage, the direct current is output at a constant current, which not only protects the circuit, but also prevents the load from being immediately powered off, so that the circuit can be applied to scenarios with large current spikes; when the load increases further, that is, when the voltage of the first node is greater than the second preset voltage, the direct current is stopped from being transmitted, thereby avoiding damage to the circuit, thereby ensuring the safety of the circuit at a low cost and improving the applicability of the circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical application in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1 A schematic diagram of a protection circuit provided in one embodiment of the present application;

[0033] Figure 2 Another structural schematic diagram of a protection circuit provided in an embodiment of the present application;

[0034] Figure 3 Another structural schematic diagram of a protection circuit provided in an embodiment of the present application;

[0035] Figure 4 A partial exemplary circuit schematic diagram of a protection circuit provided in one embodiment of the present application. DETAILED DESCRIPTION

[0036] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0037] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0038] It should be understood that the orientation or position relationship indicated by terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0039] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0040] Figure 1 A schematic diagram of the structure of a protection circuit provided by an embodiment of the present application is shown. For the sake of convenience, only the parts related to the present embodiment are shown, which are described in detail as follows:

[0041] The protection circuit and the load 500 are connected to a first node A. The protection circuit includes a current detection circuit 100 , a current limiting protection circuit 200 , a shutdown circuit 300 and a switch circuit 400 .

[0042] The current detection circuit 100 is configured to detect the current of the direct current to output a detection signal.

[0043] The current limiting protection circuit 200 is connected to the current detection circuit 100 and is configured to output a first control voltage in response to a voltage of a detection signal being greater than a first preset voltage.

[0044] The shutdown circuit 300 is connected to the first node A and the current limiting protection circuit 200, and is configured to output a shutdown signal in response to the voltage of the first node A being greater than a second preset voltage, wherein the voltage of the first node A is the difference between the voltage of the DC power and the voltage drop of the load 500.

[0045] The switching circuit 400 is connected to the first node A, the current detection circuit 100, the current limiting protection circuit 200 and the shutdown circuit 300, and is configured to stop transmitting direct current in response to a shutdown signal, and to control the direct current constant current output according to the first control voltage in response to the cessation of the shutdown signal.

[0046] It should be noted that when the resistance value of the load 500 is the first resistance value, the switch circuit 400 outputs direct current according to the first control voltage constant current, the direct current voltage received by the load 500 decreases, and the current consumed by the load 500 also decreases, and finally maintains the current size set by the current limiting protection circuit 200; when the resistance value of the load 500 is the second resistance value, the shutdown circuit 300 determines that the load 500 is short-circuited and outputs a shutdown signal, and the switch circuit 400 stops transmitting direct current in response to the shutdown signal, and the short-circuited load 500 will no longer receive any energy; wherein, the first resistance value is greater than the second resistance value, and the first preset voltage is less than the second preset voltage.

[0047] Therefore, there is no need for a power chip. Only by building a circuit with low-cost discrete devices can it be achieved that when the load increases, that is, when the voltage of the detection signal is greater than the first preset voltage and the voltage of the first node A is less than the second preset voltage, constant current output of direct current can be achieved. This not only protects the circuit, but also prevents the load 500 from being immediately powered off, so that the circuit can be applied to scenarios with large current spikes. When the load increases further, that is, when the voltage of the first node A is greater than the second preset voltage, direct current transmission is stopped, avoiding damage to the circuit, thereby ensuring the safety of the circuit at a low cost and improving the applicability of the circuit.

[0048] By way of example and not limitation, Figure 2 As shown, the current limiting protection circuit 200 includes a reference circuit 210 and a comparison circuit 220 .

[0049] The reference circuit 210 is configured to output a first preset voltage.

[0050] The comparison circuit 220 is connected to the current detection circuit 100 , the switch circuit 400 , the shutdown circuit 300 and the reference circuit 210 , and is configured to output a first control voltage according to the detection signal and the first preset voltage.

[0051] It should be noted that when the voltage of the detection signal is lower than the first preset voltage, the comparison circuit 220 outputs a second control voltage, so that the switch circuit 400 is in a low-impedance conduction state, and all the energy of the direct current is normally transmitted to the load 500; when the voltage of the detection signal is higher than the first preset voltage, the comparison circuit 220 outputs an adjustable first control voltage, the switch circuit 400 is in a semi-conduction state and controls the conduction degree of the switch circuit 400 according to the adjustable first control voltage, and outputs direct current at a constant current, wherein the second control voltage is higher than the first control voltage.

[0052] The comparison circuit 220 is used to achieve current limiting and conduction of the switch circuit 400, thereby improving the safety of the circuit.

[0053] By way of example and not limitation, Figure 3 As shown, the protection circuit further includes a recovery circuit 600 .

[0054] The recovery circuit 600 is connected to the first node A, and is configured to connect the DC power to the power ground when the switch circuit 400 stops transmitting the DC power, and to sample the current of the DC power to output a sampling signal.

[0055] The shutdown circuit 300 is further configured to stop outputting the shutdown signal when the voltage of the sampling signal is less than the second preset voltage.

[0056] The traditional hiccup protection circuit controls the switch to open briefly periodically to detect whether the resistance of the load 500 is less than the second resistance, so as to reopen the switch circuit 400. The recovery circuit 600 is used to directly turn on the switch circuit 400 after troubleshooting is completed, thereby reducing energy loss and the risk of equipment damage and improving circuit safety.

[0057] Figure 4 A partial exemplary circuit structure of a protection circuit provided by an embodiment of the present application is shown. For the sake of convenience, only the part related to the embodiment of the present application is shown, which is described in detail as follows:

[0058] The current detection circuit 100 includes a first resistor R1 .

[0059] The first end of the first resistor R1 serves as the DC current input end of the current detection circuit 100 and the detection signal output end of the current detection circuit 100, and is connected to the current limiting protection circuit 200 and the switch circuit 400 to input the DC current and output the detection signal; the second end of the first resistor R1 is connected to the power ground.

[0060] The circuit is simple and reliable.

[0061] The reference circuit 210 includes a regulator D1 , a third resistor R3 , a fourth resistor R4 , and a fifth resistor R5 .

[0062] The first end of the third resistor R3 and the first end of the fourth resistor R4 are commonly used as the first preset voltage output end of the reference circuit 210, and are connected to the comparison circuit 220 to output the first preset voltage; the second end of the third resistor R3 is connected to the negative electrode of the regulator D1, the control end of the regulator D1 and the first end of the fifth resistor R5, the second end of the fifth resistor R5 is connected to the first power supply, and the positive electrode of the regulator D1 and the second end of the fourth resistor R4 are commonly connected to the power ground.

[0063] The voltage regulator D1 can be replaced by a voltage regulator diode.

[0064] The circuit is only composed of the voltage regulator D1 and resistors, and the components are easily available and low in cost.

[0065] The comparison circuit 220 includes an operational amplifier U1 and a second resistor R2 .

[0066] The non-inverting input terminal of the operational amplifier U1 serves as the first preset voltage input terminal of the comparison circuit 220, and is connected to the reference circuit 210 to input the first preset voltage; the inverting input terminal of the operational amplifier U1 serves as the detection signal input terminal of the comparison circuit 220, and is connected to the current detection circuit 100 and the switch circuit 400 to input the detection signal; the output terminal of the operational amplifier U1 is connected to the first end of the second resistor R2, and the second end of the second resistor R2 serves as the first control voltage output terminal of the comparison circuit 220, and is connected to the switch circuit 400 and the shutdown circuit 300 to output the first control voltage.

[0067] The recovery circuit 600 includes a sixth resistor R6.

[0068] The first end of the sixth resistor R6 serves as the DC current input end of the recovery circuit 600 and the sampling signal output end of the recovery circuit 600, and is connected to the first node A to input the DC current and output the sampling signal; the second end of the sixth resistor R6 is connected to the power ground.

[0069] The sixth resistor R6 forms a recovery circuit 600, which enables the circuit to automatically recover to a normal output state after troubleshooting is completed, thereby enriching the function of the circuit.

[0070] The shutdown circuit 300 includes a voltage stabilizing diode ZD1 and a second switch tube Q2.

[0071] The cathode of the Zener diode ZD1 serves as the voltage input terminal of the first node A of the shutdown circuit 300 and the sampling signal input terminal of the shutdown circuit 300, and is connected to the first node A and the recovery circuit 600 to input the voltage of the first node A and the sampling signal; the anode of the Zener diode ZD1 is connected to the control terminal of the second switch tube Q2, and the first terminal of the second switch tube Q2 serves as the shutdown signal output terminal of the shutdown circuit 300, and is connected to the switch circuit 400 and the current limiting protection circuit 200 to output the shutdown signal; the second terminal of the second switch tube Q2 is connected to the power ground.

[0072] It should be noted that the second preset voltage is the breakdown voltage of the Zener diode ZD1 .

[0073] The second switch tube Q2 may be an N-type metal oxide semiconductor (negative channel metal oxide semiconductor, NMOS) or an NPN-type transistor.

[0074] Using a switch tube as the shut-off circuit 300 reduces energy loss and has a fast response speed.

[0075] The switch circuit 400 includes a first switch tube Q1 .

[0076] The first end of the first switch tube Q1 serves as a DC input end of the switch circuit 400 and is connected to the first node A to receive DC power; the second end of the first switch tube Q1 serves as a DC output end of the switch circuit 400 and is connected to the current detection circuit 100 and the current limiting protection circuit 200 to output DC power; the control end of the first switch tube Q1 serves as a shutdown signal input end of the switch circuit 400 and a first control voltage input end of the switch circuit 400 to input a shutdown signal and a first control voltage.

[0077] The first switch tube Q1 may be an N-type metal oxide semiconductor (negative channel metal oxide semiconductor, NMOS) or an NPN-type transistor.

[0078] A switch tube is used as the switch circuit 400, and the current limiting of the direct current is achieved by virtue of its semi-conducting state characteristic. The circuit is simple, reliable and low in cost.

[0079] The following is a combination of working principles Figure 4 As shown for further explanation:

[0080] The first end of the first switch tube Q1 is connected to direct current, and direct current is output from the second end of the first switch tube Q1. The first end of the first resistor R1 is connected to direct current, the first resistor R1 samples the current of the direct current, and outputs a detection signal from the first end of the first resistor R1 to the inverting input end of the operational amplifier U1; the voltage between the positive electrode of the regulator D1 and the negative electrode of the regulator D1 is divided by the third resistor R3 and the fourth resistor R4 as the first preset voltage, and is output from the first end of the third resistor R3 and the first end of the fourth resistor R4 to the non-inverting input end of the operational amplifier U1.

[0081] When the voltage of the detection signal is less than the first preset voltage, the operational amplifier U1 outputs the second control voltage, and the first switch tube Q1 operates in the saturation region, maintains a low-impedance conduction state, and transmits direct current normally.

[0082] When the load increases, the voltage of the detection signal is greater than the first preset voltage and the voltage of the first node A is less than the second preset voltage, the second end of the second resistor R2 outputs the first control voltage to the control end of the first switch tube Q1, the first switch tube Q1 operates in the amplification area, the on-resistance increases, and the constant current outputs direct current.

[0083] When the load increases further and the voltage at the first node A is greater than the second preset voltage, the Zener diode ZD1 breaks down. At this time, the voltage at the control end of the second switch tube Q2 is the difference between the voltage at the first node A and the breakdown voltage of the Zener diode ZD1. The second switch tube Q2 is turned on, so that the control end of the first switch tube Q1 is grounded and becomes a low level. The first switch tube Q1 is turned off and stops transmitting DC power.

[0084] After the first switch tube Q1 is turned off, the sixth resistor R6 transmits direct current to the power ground and samples the current of the direct current, and outputs a sampling signal from the first end of the sixth resistor R6 to the cathode of the voltage-stabilizing diode ZD1. When the voltage of the sampling signal is less than the second preset voltage, the voltage-stabilizing diode ZD1 is restored, the second switch tube Q2 is turned off, the control end of the first switch tube Q1 is restored to a high level, the first switch tube Q1 is turned on again, direct current is transmitted, and the circuit resumes normal operation.

[0085] An embodiment of the present application further provides an electronic device, which includes the above-mentioned protection circuit.

[0086] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0087] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A protection circuit connected to a load at a first node, characterized in that: The protection circuit comprises: A current detection circuit configured to detect the current of the direct current to output a detection signal; a current limiting protection circuit connected to the current detection circuit and configured to output a first control voltage in response to the voltage of the detection signal being greater than a first preset voltage; a shutdown circuit connected to the first node and the current limiting protection circuit, and configured to output a shutdown signal in response to a voltage of the first node being greater than a second preset voltage, wherein the voltage of the first node is a difference between a voltage of the direct current and a voltage drop of the load; The switching circuit is connected to the first node, the current detection circuit, the current limiting protection circuit and the shutdown circuit, and is configured to stop transmitting the direct current in response to the shutdown signal, and to control the direct current constant current output according to the first control voltage in response to the stopping of the shutdown signal.

2. The protection circuit according to claim 1, characterized in that: The current limiting protection circuit comprises: A reference circuit configured to output the first preset voltage; A comparison circuit is connected to the current detection circuit, the switch circuit, the shutdown circuit and the reference circuit, and is configured to output the first control voltage according to the detection signal and the first preset voltage.

3. The protection circuit according to claim 1, characterized in that: The current detection circuit includes a first resistor; The first end of the first resistor serves as the DC current input end of the current detection circuit and the detection signal output end of the current detection circuit, and is connected to the current limiting protection circuit and the switching circuit to input the DC current and output the detection signal; the second end of the first resistor is connected to the power ground.

4. The protection circuit according to claim 2, characterized in that: The reference circuit includes a voltage stabilizer, a third resistor, a fourth resistor and a fifth resistor; The first end of the third resistor and the first end of the fourth resistor serve together as the first preset voltage output end of the reference circuit, and are connected to the comparison circuit to output the first preset voltage; the second end of the third resistor is connected to the negative electrode of the regulator, the control end of the regulator and the first end of the fifth resistor, the second end of the fifth resistor is connected to the first power supply, and the positive electrode of the regulator and the second end of the fourth resistor are commonly connected to the power ground.

5. The protection circuit according to claim 2, characterized in that: The comparison circuit includes an operational amplifier and a second resistor; The non-inverting input terminal of the operational amplifier serves as the first preset voltage input terminal of the comparison circuit, and is connected to the reference circuit to input the first preset voltage; the inverting input terminal of the operational amplifier serves as the detection signal input terminal of the comparison circuit, and is connected to the current detection circuit and the switch circuit to input the detection signal; the output terminal of the operational amplifier is connected to the first end of the second resistor, and the second end of the second resistor serves as the first control voltage output terminal of the comparison circuit, and is connected to the switch circuit and the shutdown circuit to output the first control voltage.

6. The protection circuit according to claim 1, characterized in that: The protection circuit further comprises: a recovery circuit connected to the first node and configured to connect the direct current to a power ground and sample the current of the direct current to output a sampling signal when the switch circuit stops transmitting the direct current; The shutdown circuit is further configured to stop outputting the shutdown signal when the voltage of the sampling signal is less than a second preset voltage.

7. The protection circuit according to claim 6, characterized in that: The recovery circuit includes a sixth resistor; The first end of the sixth resistor serves as the DC current input end of the recovery circuit and the sampling signal output end of the recovery circuit, and is connected to the first node to input the DC current and output the sampling signal; the second end of the sixth resistor is connected to the power ground.

8. The protection circuit according to claim 6, characterized in that: The shutdown circuit includes a voltage stabilizing diode and a second switch tube; The cathode of the voltage-stabilizing diode serves as the voltage input terminal of the first node of the shutdown circuit and the sampling signal input terminal of the shutdown circuit, and is connected to the first node and the recovery circuit to input the voltage and sampling signal of the first node; the anode of the voltage-stabilizing diode is connected to the control terminal of the second switch tube, and the first terminal of the second switch tube serves as the shutdown signal output terminal of the shutdown circuit, and is connected to the switch circuit and the current limiting protection circuit to output the shutdown signal; the second terminal of the second switch tube is connected to the power ground.

9. The protection circuit according to claim 1, characterized in that: The switch circuit comprises a first switch tube; The first end of the first switch tube serves as a DC input end of the switch circuit and is connected to the first node to receive the DC power; the second end of the first switch tube serves as a DC output end of the switch circuit and is connected to the current detection circuit and the current limiting protection circuit to output the DC power; the control end of the first switch tube serves as a shutdown signal input end of the switch circuit and a first control voltage input end of the switch circuit to input the shutdown signal and the first control voltage.

10. An electronic device, characterized in that: The invention comprises a protection circuit as claimed in any one of claims 1 to 9.

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