Overvoltage and overcurrent protection circuit and integrated circuit chip

By designing an overvoltage and overcurrent protection circuit with integrated multiple backup functions, the problem of difficulty in integrating efficient protection circuits in low-cost products in the prior art is solved, and effective protection of output power and improved circuit safety and reliability.

CN222547178UActive Publication Date: 2025-02-28SHENZHEN GROWATT NEW ENERGY TECH CO LTD
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Patent Information

Application Number
CN202420421896.X
Authority / Receiving Office
CN · China
Patent Type
Utility models(China)
Current Assignee / Owner
Filing Date
2024-03-05
Publication Date
2025-02-28
Estimated Expiration
2034-03-05

AI Technical Summary

Technical Problem

It is difficult to design an overvoltage and overcurrent protection circuit with a simple structure and easy to integrate into chip circuits. Especially in low-cost products, it is unreasonable to design an IC with a high degree of integration.

Method used

An overvoltage and overcurrent protection circuit is designed including a positive and negative connection terminal of the input power supply, a positive and negative connection terminal of the output power supply, an overvoltage monitoring circuit, an overvoltage response circuit, an overcurrent monitoring circuit and an automatic shutdown circuit. The protection circuit realizes multiple backups through multiple independent overvoltage monitoring units, ensuring that the circuit connection can be effectively cut off in overvoltage or overcurrent situations and prevent damage.

Benefits of technology

It realizes effective overvoltage and overcurrent protection of the output power supply, improves the safety and reliability of the circuit, and reduces design complexity and cost, and is suitable for various low-cost products.

✦ Generated by Eureka AI based on patent content.

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Abstract

The utility model discloses an overvoltage and overcurrent protection circuit and an integrated circuit chip. The overvoltage and overcurrent protection circuit comprises an overvoltage monitoring circuit, an overvoltage response circuit, an overcurrent monitoring circuit and an automatic cut-off circuit. The overvoltage monitoring circuit comprises at least two overvoltage monitoring units, each overvoltage monitoring unit is used for outputting a first overvoltage electric signal when an input voltage value of an input power supply exceeds a threshold value, and the overvoltage response circuit responds to the first overvoltage electric signal and sends a cut-off electric signal to the automatic cut-off circuit. The overcurrent monitoring circuit is used for sending a cut-off electric signal when the current of the input power supply exceeds a threshold value, the automatic cut-off circuit is used for outputting the input power supply when the cut-off electric signal is not received, and otherwise, the output power supply is stopped. The overvoltage monitoring circuit comprises at least two independent overvoltage monitoring units to realize multiple backups, so that overvoltage monitoring failure caused by failure of one or more overvoltage monitoring units is prevented, and the overvoltage and overcurrent protection circuit is safer and more reliable.
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Description

Technical Field

[0001] The present invention relates to the technical field of electrical device protection, and in particular to an overvoltage and overcurrent protection circuit and an integrated circuit chip. Background Art

[0002] At present, overvoltage and overcurrent protection circuits have been integrated into strong and weak current such as IC, fuses, contactors and relays. They have the characteristics of high stability, low power consumption and small package. They are widely used in embedded fields, such as household appliances, batteries and various industry products in life. In order to make the products run more efficiently while ensuring safe operation, it is necessary to design overvoltage and overcurrent protection circuits with simple structure and easy integration into chip circuits. Summary of the invention

[0003] The main purpose of this application is to simplify the overvoltage and overcurrent protection circuits integrated in chip circuits.

[0004] According to the first aspect, an embodiment provides an overvoltage and overcurrent protection circuit, including an input power positive connection terminal, an input power negative connection terminal, an output power positive connection terminal, an output power negative connection terminal, an overvoltage monitoring circuit, an overvoltage response circuit, an overcurrent monitoring circuit and an automatic cut-off circuit;

[0005] The input power positive connection terminal is used for inputting the positive electrode of the input power Vin;

[0006] The input power negative connection terminal is used for inputting the negative electrode of the input power Vin;

[0007] The output power positive connection terminal is used for outputting the positive electrode of the output power Vout;

[0008] The output power negative connection terminal is used for outputting the negative electrode of the output power Vout;

[0009] The overvoltage monitoring circuit includes at least two overvoltage monitoring units, each of which is connected between the positive connection terminal of the input power supply and the negative connection terminal of the output power supply, and the overvoltage monitoring unit is used to send a first overvoltage electrical signal to the overvoltage response circuit when the input voltage value of the input power supply Vin is greater than a first preset threshold value; at least two of the overvoltage monitoring units are used to achieve multiple backups to prevent the failure of one or more of the overvoltage monitoring units from causing the failure of the overvoltage monitoring;

[0010] The overvoltage response circuit is connected to the automatic cut-off circuit, and the overvoltage response circuit is used to send a cut-off electrical signal to the automatic cut-off circuit in response to the first overvoltage electrical signal;

[0011] The automatic cut-off circuit is connected between the input power positive connection terminal and the output power positive connection terminal, and is used to connect the input power positive connection terminal and the output power positive connection terminal when the automatic cut-off circuit does not receive the cut-off electrical signal, and disconnect the input power positive connection terminal and the output power positive connection terminal when the automatic cut-off circuit receives the cut-off electrical signal;

[0012] The overcurrent monitoring circuit is connected between the negative connection terminal of the input power supply and the negative connection terminal of the output power supply, and is used to send the cut-off electrical signal to the automatic cut-off circuit when the potential difference between the negative connection terminal of the input power supply and the negative connection terminal of the output power supply is greater than a second preset threshold.

[0013] In one embodiment, the overvoltage monitoring unit includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4 and a first MOS tube Q1; one end of the first resistor R1 is connected to the gate of the first MOS tube Q1, and the other end is used for inputting a preset working voltage source; one end of the second resistor R2 is connected to the gate of the first MOS tube Q1, and the other end is connected to the negative connection end of the output power supply; one end of the third resistor R3 is connected to the source of the first MOS tube Q1, and the other end is connected to the negative connection end of the output power supply; one end of the fourth resistor R4 is connected to the drain of the first MOS tube Q1, and the other end is connected to the positive connection end of the input power supply; the source of the first MOS tube Q1 is electrically connected to the overvoltage response circuit.

[0014] In one embodiment, the overvoltage monitoring unit further includes a first diode D1 , and the first diode D1 is connected between the source of the first MOS transistor Q1 and the overvoltage response circuit.

[0015] In one embodiment, the overvoltage response circuit includes a fifth resistor R5, a sixth resistor R6 and a first transistor Q2; one end of the fifth resistor R5 is connected to each of the overvoltage monitoring units, and the other end is connected to the control electrode of the first transistor Q2; one end of the sixth resistor R6 is connected to the control electrode of the first transistor Q2, and the other end is connected to the second electrode of the first transistor Q2; the first electrode of the first transistor Q2 is connected to the automatic cut-off circuit, and the second electrode of the first transistor Q2 is connected to the negative connection end of the output power supply.

[0016] In one embodiment, the overvoltage response circuit further includes a first capacitor C1 , one end of the first capacitor C1 is connected to the control electrode of the first transistor Q2 , and the other end of the first capacitor C1 is connected to the second electrode of the first transistor Q2 .

[0017] In one embodiment, the automatic cut-off circuit includes a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a three-terminal fuse FUSE and a second MOS tube Q3; the three-terminal fuse FUSE is respectively connected to the input power positive connection end, the output power positive connection end and one end of the ninth resistor R9, and the other end of the ninth resistor R9 is connected to the drain of the second MOS tube Q3; one end of the seventh resistor R7 is connected to the gate of the second MOS tube Q3, and the other end is used for inputting the preset working voltage source; one end of the eighth resistor R8 is connected to the gate of the second MOS tube Q3, and the other end is connected to the source of the second MOS tube Q3; the source of the second MOS tube Q3 is connected to the overvoltage response circuit and the overcurrent monitoring circuit.

[0018] In one embodiment, the overcurrent monitoring circuit includes a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13 and a second transistor Q4; one end of the tenth resistor R10 is connected to the negative connection end of the input power supply, and the other end is connected to the negative connection end of the output power supply; one end of the eleventh resistor R11 is connected to the negative connection end of the output power supply, and the other end is connected to the control electrode of the second transistor Q4; one end of the twelfth resistor R12 is connected to the control electrode of the second transistor Q4, and the other end is connected to the second electrode of the second transistor Q4; one end of the thirteenth resistor R13 is connected to the first electrode of the second transistor Q4, and the other end is used for the input of the preset working voltage source; the second electrode of the second transistor Q4 is connected to the negative connection end of the input power supply, and the first electrode of the second transistor Q4 is connected to the automatic cut-off circuit.

[0019] In one embodiment, the overcurrent monitoring circuit further includes a second capacitor C2, one end of the second capacitor C2 is connected to the control electrode of the second transistor Q4, and the other end of the second capacitor C2 is connected to the second electrode of the second transistor Q4.

[0020] In one embodiment, the first transistor Q2 and the second transistor Q4 are NPN transistors, and the first MOS transistor Q1 and the second MOS transistor Q3 are NMOS transistors; and / or the resistance value of the tenth resistor R10 is proportional to the current limiting value of the overvoltage and overcurrent protection circuit.

[0021] According to the second aspect, an embodiment provides an integrated circuit chip integrating the overvoltage and overcurrent protection circuit as described above.

[0022] According to the overvoltage and overcurrent protection circuit of the above embodiment, since the overvoltage monitoring circuit realizes multiple backups through multiple independent overvoltage monitoring units, it prevents the failure of one or more overvoltage monitoring units from causing overvoltage monitoring failure, thereby making the overvoltage and overcurrent protection circuit safer and more reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1A schematic diagram of the structure of an overvoltage and overcurrent protection circuit in an embodiment;

[0024] Figure 2 A schematic diagram of the structure of an overvoltage monitoring circuit in an embodiment;

[0025] Figure 3 A schematic diagram of circuit connections of an overvoltage monitoring unit in an embodiment;

[0026] Figure 4 A schematic diagram of circuit connections of an overvoltage response circuit in an embodiment;

[0027] Figure 5 A schematic diagram of a circuit connection for automatically cutting off a circuit in an embodiment;

[0028] Figure 6 Schematic diagram of circuit connection of an overcurrent monitoring circuit in an embodiment. DETAILED DESCRIPTION

[0029] The present invention is further described in detail below by specific embodiments in conjunction with the accompanying drawings. Wherein similar elements in different embodiments adopt associated similar element numbers. In the following embodiments, many detailed descriptions are for making the present application better understood. However, those skilled in the art can easily recognize that some features can be omitted in different situations, or can be replaced by other elements, materials, methods. In some cases, some operations related to the present application are not shown or described in the specification, this is to avoid the core part of the present application being overwhelmed by too much description, and for those skilled in the art, it is not necessary to describe these related operations in detail, and they can fully understand the related operations according to the description in the specification and the general technical knowledge in the art.

[0030] In addition, the features, operations or characteristics described in the specification can be combined in any appropriate manner to form various implementations. At the same time, the steps or actions in the method description can also be interchanged or adjusted in a manner that is obvious to those skilled in the art. Therefore, the various sequences in the specification and the drawings are only for the purpose of clearly describing a certain embodiment and are not meant to be a required sequence, unless otherwise specified that a certain sequence must be followed.

[0031] The serial numbers assigned to the components herein, such as "first", "second", etc., are only used to distinguish the objects described and do not have any order or technical meaning. The "connection" and "coupling" mentioned in this application, unless otherwise specified, include direct and indirect connections (couplings).

[0032] In the prior art, since the cost requirements of low-end products are relatively high, it is unreasonable to select ICs with a higher degree of integration. Therefore, for low-priced products, this application selects a circuit structure with cheap components and capable of double protection, which not only reduces the complexity of the overall design, but also can be applied to various products.

[0033] Embodiment 1

[0034] Please refer to Figure 1 , is a schematic diagram of the structure of an overvoltage and overcurrent protection circuit in an embodiment, the overvoltage and overcurrent protection circuit includes an input power positive connection terminal VI+, an input power negative connection terminal VI-, an output power positive connection terminal VO+, an output power negative connection terminal VO-, an overvoltage monitoring circuit 1, an overvoltage response circuit 2, an overcurrent monitoring circuit 3 and an automatic cut-off circuit 4. Among them, the connection node A1 is connected between the overvoltage monitoring circuit 1 and the overvoltage response circuit 2, and the connection node B1 is connected between the overvoltage response circuit 2, the overcurrent monitoring circuit 3 and the automatic cut-off circuit 4. The input power positive connection terminal VI+ is used for the positive input of the input power Vin, the input power negative connection terminal VI- is used for the negative input of the input power Vin, the output power positive connection terminal VO+ is used for the positive output of the output power Vout, and the output power negative connection terminal VO- is used for the negative output of the output power Vout.

[0035] Please refer to Figure 2, is a schematic diagram of the structure of an overvoltage monitoring circuit in an embodiment, the overvoltage monitoring circuit 1 includes at least two overvoltage monitoring units 10, each of which is connected between the positive connection terminal VI+ of the input power supply and the negative connection terminal VO- of the output power supply, and the overvoltage monitoring unit 10 is used to send a first overvoltage electrical signal to the overvoltage response circuit 2 when the input voltage value of the input power supply Vin is greater than a first preset threshold. At least two overvoltage monitoring units 10 are used to achieve multiple backups to prevent the failure of overvoltage monitoring caused by the failure of one or more overvoltage monitoring units 10. The overvoltage response circuit 2 is connected to the automatic cut-off circuit 4, and the overvoltage response circuit 2 is used to send a cut-off electrical signal to the automatic cut-off circuit 4 in response to the first overvoltage electrical signal. The automatic cut-off circuit 4 is connected between the input power positive connection terminal VI+ and the output power positive connection terminal VO+. The automatic cut-off circuit 4 is used to connect the input power positive connection terminal VI+ and the output power positive connection terminal VO+ when the automatic cut-off circuit does not receive the cut-off electrical signal, and disconnect the input power positive connection terminal VI+ and the output power positive connection terminal VO+ when the cut-off electrical signal is received, so as to realize overvoltage protection of the output power Vout. The overcurrent monitoring circuit 3 is connected between the input power negative connection terminal VI- and the output power negative connection terminal VO-, and is used to send a cut-off electrical signal to the automatic cut-off circuit 4 when the potential difference between the input power negative connection terminal VI- and the output power negative connection terminal VO- is greater than a second preset threshold, so as to realize overcurrent protection of the output power Vout through the automatic cut-off circuit 4.

[0036] Please refer to Figure 3 , is a circuit connection diagram of an overvoltage monitoring unit in an embodiment, the overvoltage monitoring unit 10 includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4 and a first MOS tube Q1. One end of the first resistor R1 is connected to the gate of the first MOS tube Q1, and the other end is used for inputting a preset working voltage source Vcc. One end of the second resistor R2 is connected to the gate of the first MOS tube Q1, and the other end is connected to the negative connection terminal VO- of the output power supply. One end of the third resistor R3 is connected to the source of the first MOS tube Q1, and the other end is connected to the negative connection terminal VO- of the output power supply. One end of the fourth resistor R4 is connected to the drain of the first MOS tube Q1, and the other end is connected to the positive connection terminal VI+ of the input power supply. The source of the first MOS tube Q1 is connected to the overvoltage response circuit 2. In one embodiment, the overvoltage monitoring unit 10 also includes a first diode D1, and the first diode D1 is connected between the source of the first MOS tube Q1 and the overvoltage response circuit 2.

[0037] Please refer to Figure 4, is a circuit connection diagram of an overvoltage response circuit in an embodiment, the overvoltage response circuit 2 includes a fifth resistor R5, a sixth resistor R6 and a first transistor Q2. One end of the fifth resistor R5 is connected to each overvoltage monitoring unit 10, and the other end is connected to the control electrode of the first transistor Q2. One end of the sixth resistor R6 is connected to the control electrode of the first transistor Q2, and the other end is connected to the second electrode of the first transistor Q2. The first electrode of the first transistor Q2 is connected to the automatic cut-off circuit 4, and the second electrode of the first transistor Q2 is connected to the negative connection terminal VO- of the output power supply. In one embodiment, the overvoltage response circuit 2 also includes a first capacitor C1, one end of the first capacitor C1 is connected to the control electrode of the first transistor Q2, and the other end is connected to the second electrode of the first transistor Q2.

[0038] Please refer to Figure 5 , is a circuit connection diagram of an automatic cut-off circuit in an embodiment, wherein the automatic cut-off circuit 3 includes a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a three-terminal fuse FUSE and a second MOS tube Q3. The three connection ends of the three-terminal fuse FUSE are respectively connected to the input power positive connection end VI+, the output power positive connection end VO+ and one end of the ninth resistor R9, and the other end of the ninth resistor R9 is connected to the drain of the second MOS tube Q3. One end of the seventh resistor R7 is connected to the gate of the second MOS tube Q3, and the other end is used for inputting a preset working voltage source Vcc. One end of the eighth resistor R8 is connected to the gate of the second MOS tube Q3, and the other end is connected to the source of the second MOS tube Q3. The source of the second MOS tube Q3 is connected to the overvoltage response circuit 2 and the overcurrent monitoring circuit 4.

[0039] Please refer to Figure 6 , is a circuit connection diagram of an overcurrent monitoring circuit in an embodiment, the overcurrent monitoring circuit 4 includes a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13 and a second transistor Q4. One end of the tenth resistor R10 is connected to the negative connection terminal VI- of the input power supply, and the other end is connected to the negative connection terminal VO- of the output power supply. One end of the eleventh resistor R11 is connected to the negative connection terminal VO- of the output power supply, and the other end is connected to the control electrode of the second transistor Q4. One end of the twelfth resistor R12 is connected to the control electrode of the second transistor Q4, and the other end is connected to the second electrode of the second transistor Q4. One end of the thirteenth resistor R13 is connected to the first electrode of the second transistor Q4, and the other end is used for the input of the preset working voltage source Vcc. The second electrode of the second transistor Q4 is connected to the negative connection terminal VI- of the input power supply, and the first electrode of the second transistor Q4 is connected to the automatic cut-off circuit 3. In one embodiment, the overcurrent monitoring circuit further includes a second capacitor C2, one end of the second capacitor C2 is connected to the control electrode of the second transistor Q4, and the other end of the second capacitor C2 is connected to the second electrode of the second transistor Q4.

[0040] In one embodiment, the first transistor Q2 and the second transistor Q4 are NPN transistors, and the first MOS transistor Q1 and the second MOS transistor Q3 are NMOS transistors. In one embodiment, the resistance value of the tenth resistor R10 is proportional to the current limiting value of the overvoltage and overcurrent protection circuit.

[0041] An integrated circuit chip is also disclosed in one embodiment of the present application, integrating the overvoltage and overcurrent protection circuit as described above.

[0042] In one embodiment of the present application, the overvoltage and overcurrent protection circuit includes three NMOS tubes, two NPN transistors, a three-terminal fuse (which can be replaced by a MOS tube control circuit), fifteen resistors, two capacitors, two ordinary diodes, a preset working voltage source Vcc and an input power supply Vin, to achieve overvoltage and overcurrent protection for the output power supply Vout. When the voltage of the front-stage power supply (input power supply Vin) is continuously too high, two-way monitoring (two overvoltage monitoring units) are provided, and the time to shut down the rear-stage output is controlled by the capacitance size of the first capacitor C1. When the current of the rear-stage power supply (output power supply Vout) is continuously too large, the time to shut down the rear-stage output is controlled by the capacitance size of the second capacitor C2, thereby reducing the overall manufacturing cost.

[0043] The protection process of the overvoltage and overcurrent protection circuit disclosed in the present application is described below through a specific embodiment, and the voltage value of the preset working voltage source Vcc is set to 12V.

[0044] Application scenario 1: When the voltage of the input power supply Vin is greater than 20v, the output power supply Vout has no output. The implementation process is:

[0045] When the voltage of the input power supply Vin is greater than 20V, due to the presence of the 12V preset working voltage source Vcc, the first resistor R1 and the second resistor R2 divide the voltage, resulting in the first MOS tube Q1 (low conduction voltage V DS ≤0.1V), then the third resistor R3 and the fourth resistor R4 divide the voltage, and the overvoltage monitoring unit outputs a voltage signal greater than 0.7V (the first overvoltage electrical signal) to the overvoltage response circuit through the connection node A1. After the overvoltage response circuit obtains the first overvoltage electrical signal, the first transistor Q2 is turned on, and the fifth resistor R5 and the sixth resistor R6 divide the voltage, and then the seventh resistor R7 and the eighth resistor R8 of the circuit are automatically cut off, causing the second MOS tube Q3 to be turned on, and the current flowing through the ninth resistor R9 is the time to pull the three-terminal fuse FUSE to melt, thereby achieving no output of the output power supply Vout.

[0046] Application scenario 2: When the voltage of the input power supply Vin is less than 20V, the input power supply positive connection terminal VI+ and the output power supply positive connection terminal VO+ are directly electrically connected, and the output power supply Vout is output normally. The implementation process is:

[0047] When the voltage of the input power supply Vin is less than 20V, due to the presence of the 12V preset working voltage source Vcc, the first resistor R1 and the second resistor R2 divide the voltage, resulting in the first MOS tube Q1 (low conduction voltage V DS ≤0.1V), then the third resistor R3 and the fourth resistor R4 cannot divide the voltage, and the overvoltage monitoring unit cannot output the first overvoltage electrical signal (there is no voltage difference greater than 0.7V at the connection node A1), resulting in the first transistor Q2 being turned off, and then the fifth resistor R5 and the sixth resistor R6 cannot divide the voltage, resulting in the second MOS tube Q3 being turned off, the three-terminal fuse has no action and is in the on state, and the input power positive connection terminal VI+ and the output power positive connection terminal VO+ are directly electrically connected.

[0048] Application scenario three, when the output current (the current between the negative connection terminal VI- of the input power supply to the negative connection terminal VO- of the output power supply) is greater than the set 116A, the voltage of the tenth resistor R10 of the overcurrent monitoring circuit exceeds 0.7V, so that the voltage on the twelfth resistor R12 causes the second transistor Q4 to turn on, and then automatically cuts off the seventh resistor R7 and the eighth resistor R8 of the circuit to divide the voltage, causing the second MOS tube Q3 to turn on, and the current flowing through the ninth resistor R9 is the time to pull the three-terminal fuse FUSE to melt, thereby achieving no output of the output power Vout.

[0049] In an overvoltage and overcurrent protection circuit disclosed in one embodiment of the present application, the resistance value of the third resistor R3 can set the trigger voltage of the overvoltage monitoring unit, the first diode D1 is used to prevent multiple overvoltage monitoring units from influencing each other, and the direction between the negative connection terminal VI- of the input power supply to the negative connection terminal of the output power supply can be adjusted by switching the position to select the protection of the input current and the output current. The first capacitor C1 and the second capacitor C2 are used to prevent false triggering, and the protection time can be controlled by changing the size of the capacitance. The current trigger condition of the overcurrent monitoring circuit can be adjusted by adjusting the resistance value of the tenth resistor R10.

[0050] The overvoltage and overcurrent protection circuit disclosed in the present application includes an overvoltage monitoring circuit, an overvoltage response circuit, an overcurrent monitoring circuit and an automatic cut-off circuit. The overvoltage monitoring circuit includes at least two overvoltage monitoring units, each of which is used to output a first overvoltage electrical signal when the input voltage value of the input power source exceeds a threshold value, the overvoltage response circuit sends a cut-off electrical signal to the automatic cut-off circuit in response to the first overvoltage electrical signal, the overcurrent monitoring circuit is used to send a cut-off electrical signal when the current of the input power source exceeds a threshold value, and the automatic cut-off circuit is used to output the input power source when the cut-off electrical signal is not received, and stop outputting the power source otherwise. Since the overvoltage monitoring circuit includes at least two independent overvoltage monitoring units, multiple backups are realized to prevent the failure of one or more overvoltage monitoring units from causing the failure of the overvoltage monitoring, thereby making the overvoltage and overcurrent protection circuit safer and more reliable.

[0051] The above specific examples are used to illustrate the present invention, which is only used to help understand the present invention and is not intended to limit the present invention. For those skilled in the art, according to the concept of the present invention, some simple deductions, modifications or substitutions can be made.

Claims

1. An overvoltage and overcurrent protection circuit, characterized in that: It includes an input power positive connection terminal, an input power negative connection terminal, an output power positive connection terminal, an output power negative connection terminal, an overvoltage monitoring circuit, an overvoltage response circuit, an overcurrent monitoring circuit and an automatic cut-off circuit; The input power positive connection terminal is used for inputting the positive electrode of the input power Vin; The input power negative connection terminal is used for inputting the negative electrode of the input power Vin; The output power positive connection terminal is used for outputting the positive electrode of the output power Vout; The output power negative connection terminal is used for outputting the negative electrode of the output power Vout; The overvoltage monitoring circuit includes at least two overvoltage monitoring units, each of which is connected between the positive connection terminal of the input power supply and the negative connection terminal of the output power supply, and the overvoltage monitoring unit is used to send a first overvoltage electrical signal to the overvoltage response circuit when the input voltage value of the input power supply Vin is greater than a first preset threshold value; at least two of the overvoltage monitoring units are used to achieve multiple backups to prevent the failure of one or more of the overvoltage monitoring units from causing the failure of the overvoltage monitoring; The overvoltage response circuit is connected to the automatic cut-off circuit, and the overvoltage response circuit is used to send a cut-off electrical signal to the automatic cut-off circuit in response to the first overvoltage electrical signal; The automatic cut-off circuit is connected between the input power positive connection terminal and the output power positive connection terminal, and is used to connect the input power positive connection terminal and the output power positive connection terminal when the automatic cut-off circuit does not receive the cut-off electrical signal, and disconnect the input power positive connection terminal and the output power positive connection terminal when the automatic cut-off circuit receives the cut-off electrical signal; The overcurrent monitoring circuit is connected between the negative connection terminal of the input power supply and the negative connection terminal of the output power supply, and is used to send the cut-off electrical signal to the automatic cut-off circuit when the potential difference between the negative connection terminal of the input power supply and the negative connection terminal of the output power supply is greater than a second preset threshold.

2. The overvoltage and overcurrent protection circuit according to claim 1, characterized in that: The overvoltage monitoring unit includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4 and a first MOS tube Q1; One end of the first resistor R1 is connected to the gate of the first MOS transistor Q1, and the other end is used for inputting a preset working voltage source; One end of the second resistor R2 is connected to the gate of the first MOS transistor Q1, and the other end is connected to the negative connection end of the output power supply; One end of the third resistor R3 is connected to the source of the first MOS transistor Q1, and the other end is connected to the negative connection end of the output power supply; One end of the fourth resistor R4 is connected to the drain of the first MOS transistor Q1, and the other end is connected to the positive connection end of the input power supply; The source of the first MOS transistor Q1 is electrically connected to the overvoltage response circuit.

3. The overvoltage and overcurrent protection circuit according to claim 2, characterized in that: The overvoltage monitoring unit further includes a first diode D1 , which is connected between the source of the first MOS transistor Q1 and the overvoltage response circuit.

4. The overvoltage and overcurrent protection circuit according to claim 2, characterized in that: The overvoltage response circuit includes a fifth resistor R5, a sixth resistor R6 and a first transistor Q2; One end of the fifth resistor R5 is connected to each of the overvoltage monitoring units, and the other end is connected to the control electrode of the first transistor Q2; One end of the sixth resistor R6 is connected to the control electrode of the first transistor Q2, and the other end is connected to the second electrode of the first transistor Q2; The first electrode of the first transistor Q2 is connected to the automatic cut-off circuit, and the second electrode of the first transistor Q2 is connected to the negative connection end of the output power supply.

5. The overvoltage and overcurrent protection circuit according to claim 4, characterized in that: The overvoltage response circuit further includes a first capacitor C1 , one end of which is connected to the control electrode of the first transistor Q2 , and the other end of which is connected to the second electrode of the first transistor Q2 .

6. The overvoltage and overcurrent protection circuit according to claim 4, characterized in that: The automatic cut-off circuit includes a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a three-terminal fuse FUSE and a second MOS tube Q3; A three-terminal fuse FUSE is respectively connected to the input power positive connection terminal, the output power positive connection terminal and one end of a ninth resistor R9, and the other end of the ninth resistor R9 is connected to the drain of the second MOS tube Q3; One end of the seventh resistor R7 is connected to the gate of the second MOS transistor Q3, and the other end is used for inputting the preset working voltage source; One end of the eighth resistor R8 is connected to the gate of the second MOS transistor Q3, and the other end is connected to the source of the second MOS transistor Q3; The source of the second MOS transistor Q3 is connected to the overvoltage response circuit and the overcurrent monitoring circuit.

7. The overvoltage and overcurrent protection circuit according to claim 6, characterized in that: The overcurrent monitoring circuit includes a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13 and a second transistor Q4; One end of the tenth resistor R10 is connected to the negative connection end of the input power supply, and the other end is connected to the negative connection end of the output power supply; One end of the eleventh resistor R11 is connected to the negative connection end of the output power supply, and the other end is connected to the control electrode of the second transistor Q4; One end of the twelfth resistor R12 is connected to the control electrode of the second transistor Q4, and the other end is connected to the second electrode of the second transistor Q4; One end of the thirteenth resistor R13 is connected to the first electrode of the second transistor Q4, and the other end is used for inputting the preset working voltage source; The second electrode of the second transistor Q4 is connected to the negative connection terminal of the input power supply, and the first electrode of the second transistor Q4 is connected to the automatic cut-off circuit.

8. The overvoltage and overcurrent protection circuit according to claim 7, characterized in that: The overcurrent monitoring circuit further includes a second capacitor C2, one end of the second capacitor C2 is connected to the control electrode of the second transistor Q4, and the other end of the second capacitor C2 is connected to the second electrode of the second transistor Q4.

9. The overvoltage and overcurrent protection circuit according to claim 7, characterized in that: The first transistor Q2 and the second transistor Q4 are NPN transistors, and the first MOS transistor Q1 and the second MOS transistor Q3 are NMOS transistors.

10. An integrated circuit chip, characterized in that: The overvoltage and overcurrent protection circuit as claimed in any one of claims 1 to 9 is integrated.