MOS tube overcurrent protection circuit and power electronic equipment

Abstract

The utility model discloses an MOS tube over-current protection circuit and power electronic equipment, relates to the technical field of H-bridge circuits, and solves the technical problem that an over-current protection circuit cannot provide enough protection performance for the H-bridge circuit. The circuit comprises an enabling circuit, a first driving circuit, a second driving circuit and a current detection circuit, the enabling circuit is connected with a power supply VCC and controls power supply of the H-bridge circuit through level signal change; the first driving circuit and the second driving circuit are connected with the H-bridge circuit and enable the H-bridge circuit to be switched on or switched off through PWM pulse signals. And the current detection circuit is used for detecting the magnitude of the current output to the load by the H-bridge circuit, and cutting off the power supply of the enabling circuit for overcurrent protection if overcurrent occurs. According to the utility model, the current detection circuit is adopted to realize real-time monitoring of load current, an overcurrent phenomenon can be detected, power supply can be cut off immediately, the accuracy and sensitivity of overcurrent detection are ensured, and sufficient protection performance is provided.

Description

TECHNICAL FIELD

[0001] The utility model relates to H bridge circuit technical field especially relates to a MOS pipe overcurrent protection circuit and power electronic device. BACKGROUND

[0002] MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) is widely used in various power electronic devices such as motor drive, switching power supply, inverter, etc. due to its high efficiency, fast switching speed and easy to drive. However, in practical applications, due to load mutation, short circuit or other abnormal conditions, overcurrent phenomenon may occur, which poses a threat to the safety of MOSFET and the entire circuit.

[0003] Existing overcurrent protection methods are usually implemented through external current detection circuits or overcurrent protection mechanisms integrated in MOSFET. However, these methods often have slow response speed, low accuracy, poor reliability and other problems, which cannot effectively protect MOSFET from damage. Especially in high-frequency switching applications, the delay of these protection methods may cause MOSFET to withstand excessively high current in a short time, ultimately leading to device failure.

[0004] H-bridge circuit is a common power conversion topology, widely used in DC motor drive, inverter and other bidirectional power conversion applications. H-bridge is composed of four MOSFETs, by alternatingly turning on different MOSFET combinations, it can realize forward and reverse control of the load. However, MOSFETs in H-bridge circuit are susceptible to overcurrent, especially when half-bridge signals share a common drive signal, once overcurrent occurs in a certain MOSFET, it may affect the normal operation of the entire system. In addition, H-bridge circuit usually needs to handle large current and power, therefore the requirement for overcurrent protection is more stringent. Traditional overcurrent protection schemes are difficult to meet the high reliability and fast response requirements of H-bridge circuit. Existing overcurrent protection technologies have deficiencies in response speed, accuracy and reliability, especially in H-bridge circuit, they cannot provide sufficient protection performance. Therefore, it is particularly important to develop an efficient and reliable MOSFET overcurrent protection circuit.

[0005] In the process of implementing the utility model, the applicant found that there are at least the following problems in the prior art:

[0006] The overcurrent protection circuit has deficiencies in response speed, accuracy and reliability, and cannot provide sufficient protection performance for H-bridge circuit. UTILITY MODEL CONTENTS

[0007] The utility model discloses a MOS tube overcurrent protection circuit and power electronic equipment to solve the overcurrent protection circuit in prior art in response speed, precision and reliability exist the technical problem of insufficient, unable to provide sufficient protection performance for H bridge circuit.

[0008] To achieve the above object, the utility model provides the following technical scheme:

[0009] The utility model provides a MOS tube overcurrent protection circuit, including enable circuit, first drive circuit, second drive circuit and current detection circuit, the enable circuit is connected with power VCC, and the power supply of H bridge circuit is controlled through level signal change, first drive circuit, second drive circuit all are connected with H bridge circuit, and all through PWM pulse signal makes the conduction or cut -off of different MOS tube in H bridge circuit, current detection circuit is connected with first drive circuit, second drive circuit, H bridge circuit, enable circuit, is used for detecting the current size of load output of H bridge circuit, if the current overcurrent appears, cut off enable circuit and carry out overcurrent protection.

[0010] Preferably, the overcurrent protection circuit further comprises an inverter, the inverter reverses the polarity of the input level signal, the input end of the inverter is connected with the first drive circuit, the second drive circuit and the current detection circuit, and the output end is connected with the enable circuit.

[0011] Preferably, the enable circuit comprises a P-type MOS transistor Q1 and an NPN-type triode Q2, the source of the MOS transistor Q1 is connected with the power VCC, the drain is connected with the H bridge circuit, and the gate is connected with the collector of the triode Q2; the emitter of the triode Q2 is connected with the ground, and the base is connected with the inverter.

[0012] Preferably, the enable circuit further comprises a resistor R1, a resistor R2, a resistor R3, a resistor R4 and a stabilizing diode D1, the stabilizing diode D1 is used for stabilizing the source-gate voltage of the MOS transistor Q1; one end of the resistor R2 is connected with the power VCC and the source of the MOS transistor Q1, and the other end is connected with the resistor R4 and the gate of the MOS transistor Q1; one end of the resistor R4 is connected with the resistor R2 and the gate of the MOS transistor Q1, and the other end is connected with the collector of the triode Q2; one end of the resistor R1 is connected with the inverter, and the other end is connected with the resistor R3 and the base of the triode Q2; one end of the resistor R3 is connected with the resistor R1 and the base of the triode Q2, and the other end is connected with the ground.

[0013] Preferably, the PWM pulse signal comprises a first PWM pulse signal and a second PWM pulse signal, the first PWM pulse signal and the second PWM pulse signal are signal inverses, the first driving circuit corresponds to the first PWM pulse signal, and the second driving circuit corresponds to the second PWM pulse signal.

[0014] Preferably, the first driving circuit comprises NPN transistors Q3, Q4 and Q5, the base of the transistor Q3 is connected with the current detection circuit and the input end of the inverter, the emitter is grounded, and the collector is connected with the base of the MOS transistor Q4 and the first PWM pulse signal; the base of the transistor Q4 is connected with the collector of the MOS transistor Q3 and the first PWM pulse signal, the emitter is grounded, and the collector is connected with the H-bridge circuit and the power supply VCC; and the base of the transistor Q5 is connected with the first PWM pulse signal, the emitter is grounded, and the collector is connected with the enabling circuit and the H-bridge circuit.

[0015] Preferably, the second driving circuit comprises NPN transistors Q10, Q11 and Q12, the base of the transistor Q10 is connected with the second PWM pulse signal, the emitter is grounded, and the collector is connected with the H-bridge circuit; the base of the transistor Q11 is connected with the second PWM pulse signal, the emitter is grounded, and the collector is connected with the power supply VCC and the H-bridge circuit; and the base of the transistor Q12 is connected with the current detection circuit, the emitter is grounded, and the collector is connected with the second PWM pulse signal.

[0016] Preferably, the current detection circuit comprises a comparator U2 and a current detection resistor R16, one end of the current detection resistor R16 is connected with the comparator U2 and the H-bridge circuit, and the other end is grounded; the positive electrode of the comparator U2 is connected with the current detection resistor R16 and the H-bridge circuit, the negative electrode is connected with a reference voltage VREF, and the output end is connected with the input ends of the first driving circuit, the second driving circuit and the inverter.

[0017] Preferably, the overcurrent detection circuit further comprises a capacitor C1 and a pull-up resistor R15, one end of the capacitor C1 is connected with the current detection resistor R16, and the other end is grounded, so as to keep the sampling voltage of the current detection resistor R16 stable; one end of the pull-up resistor R15 is connected with the positive power supply end of the comparator U2, and the other end is connected with the output end of the comparator U2.

[0018] A power electronic device, comprising the MOS transistor overcurrent protection circuit according to any one of the above.

[0019] The above technical solutions have the following advantages or beneficial effects:

[0020] This invention employs a current detection circuit to achieve real-time monitoring of the load current. It can detect overcurrent phenomena within microseconds and immediately cut off the power supply, thoroughly preventing any potential damage and ensuring the accuracy and sensitivity of overcurrent detection, thus providing sufficient protection for the H-bridge circuit. The H-bridge circuit is controlled by a first drive circuit, a second drive circuit, and a PWM pulse signal, simplifying the control logic. Furthermore, the enable circuit controls the power supply to and from the entire H-bridge circuit, simplifying the circuit design. Simultaneously, the current detection and protection logic are tightly integrated into the H-bridge circuit, reducing the number of external components and improving the circuit's compactness and maintainability. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings:

[0022] Figure 1 This is a circuit diagram of a MOS transistor overcurrent protection circuit according to Embodiment 1 of this utility model;

[0023] Figure 2 This is a current diagram showing the output levels of the first PWM pulse signal and the second PWM pulse signal when they are both low, according to Embodiment 1 of this utility model.

[0024] Figure 3 This is a current diagram showing the output levels of the first PWM pulse signal and the second PWM pulse signal when they are low, according to Embodiment 1 of this utility model.

[0025] Figure 4 This is a current diagram of the load when an overcurrent occurs in Embodiment 1 of this utility model. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this utility model clearer, various exemplary embodiments described below will be referenced to the accompanying drawings, which form part of the exemplary embodiments, illustrating various exemplary embodiments that may be adopted to implement this utility model. 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 this disclosure. It should be understood that they are merely examples of processes, methods, and apparatuses consistent with some aspects of this utility model disclosed as detailed in the appended claims, and other embodiments may be used, or structural and functional modifications may be made to the embodiments listed herein without departing from the scope and spirit of this utility model.

[0027] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," etc., indicate the orientation or positional relationship based on the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the referred element must have a specific orientation, or be constructed and operated in a specific orientation. The terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. The term "multiple" means two or more. The terms "connected" and "linked" should be interpreted broadly, for example, they can be fixed connections, detachable connections, integral connections, mechanical connections, electrical connections, communication connections, direct connections, indirect connections through an intermediate medium, and can be the internal connection of two elements or the interaction relationship between two elements. The term "and / or" includes any and all combinations of one or more of the related listed items. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0028] To illustrate the technical solution described in this utility model, specific embodiments are described below, showing only the parts related to the embodiments of this utility model.

[0029] Example 1:

[0030] like Figure 1 As shown, this utility model provides a MOSFET overcurrent protection circuit, including an enable circuit, a first drive circuit, a second drive circuit, and a current detection circuit. The enable circuit is connected to the power supply VCC and controls the power supply of the H-bridge circuit through level signal changes. The first and second drive circuits are both connected to the H-bridge circuit and use PWM pulse signals to turn different MOSFETs in the H-bridge circuit on or off, thereby facilitating the control of the load current direction. The current detection circuit is connected to the first drive circuit, the second drive circuit, the H-bridge circuit, and the enable circuit. It is used to detect the current output from the H-bridge circuit to the load (in this embodiment, the load motor U3). If an overcurrent occurs, i.e., the load current exceeds the normal value, the enable circuit is disconnected for overcurrent protection. After the enable circuit is disconnected, the H-bridge circuit is not powered. In this embodiment, the current detection circuit is used to achieve real-time monitoring of the load current. It can detect overcurrent phenomena within a few microseconds and immediately disconnect the power supply to completely prevent any potential damage, ensuring the accuracy and sensitivity of overcurrent detection and providing sufficient protection for the H-bridge circuit. The H-bridge circuit simplifies control logic through the first and second drive circuits and PWM pulse signals. Furthermore, the enable circuit controls the power supply to and from the entire H-bridge circuit, simplifying circuit design. Simultaneously, the current detection and protection logic are tightly integrated into the H-bridge circuit, reducing the number of external components and improving circuit compactness and maintainability.

[0031] As an optional embodiment, the overcurrent protection circuit further comprises an inverter U1, which reverses the polarity of the input level signal, i.e. input high level output low level and input low level output high level, the input end of the inverter is connected with the first driving circuit, the second driving circuit and the current detection circuit, and the output end is connected with the enable circuit, so as to realize the feedback of the output level signal of the current detection circuit and control the access or disconnection of the power supply VCC through the enable circuit.

[0032] As an optional embodiment, the enable circuit comprises a P-type MOS tube Q1 and an NPN type triode Q2; the source of the MOS tube Q1 is connected with the power supply VCC, the drain is connected with the H-bridge circuit, and the gate is connected with the collector of the triode Q2; the emitter of the triode Q2 is connected with the ground, and the base is connected with the inverter. The enable circuit further comprises a resistor R1, a resistor R2, a resistor R3, a resistor R4 and a stabilizing diode D1; the resistor R1 is the base current limiting resistor of the triode Q2, and the resistor R3 is used to prevent the base and emitter of the triode Q2 from being misdirected. The resistor R2 is the voltage dividing resistor between the gate and the source of the MOS tube Q1, the stabilizing diode D1 stabilizes the voltage between the gate and the source of the MOS tube Q1, the resistor R2 and the resistor R4 constitute a voltage dividing network, and the ratio of the resistor R2 and the resistor R4 is adjusted. Since the driving voltage formula of the MOS tube Q1 is: and the maximum VGE breakdown voltage of the MOS tube Q1 is about 20V, it is necessary to ensure that the VGE is within 20V, so that the ratio of the resistor R2 and the resistor R4 depends on the size of the power supply VCC, and the voltage dividing of the resistor R2 can be about 10V under different power supply VCC, so as to ensure the normal work of the MOS tube Q1. The stabilizing diode D1 is used to stabilize the voltage between the source and the gate of the MOS tube Q1; one end of the resistor R2 is connected with the power supply VCC and the source of the MOS tube Q1, and the other end is connected with the resistor R4 and the gate of the MOS tube Q1; one end of the resistor R4 is connected with the resistor R2 and the gate of the MOS tube Q1, and the other end is connected with the collector of the triode Q2; one end of the resistor R1 is connected with the inverter, and the other end is connected with the resistor R3 and the base of the triode Q2; one end of the resistor R3 is connected with the resistor R1 and the base of the triode Q2, and the other end is connected with the ground.

[0033] As an optional embodiment, as shown in Figure 1 the P-type MOS tube Q6, the N-type MOS tube Q7, the P-type MOS tube Q8 and the N-type MOS tube Q9 constitute an H-bridge circuit, and the first driving circuit and the second driving circuit are symmetrical and consistent in structure. The resistor R13 and the resistor R11 constitute a voltage dividing network to ensure that the voltage difference between the gate and the source of the MOS tube Q6 is about 10V, and the stabilizing diode D2 stabilizes the voltage between the gate and the source of the MOS tube Q6.

[0034] As an optional embodiment, the PWM pulse signal includes a first PWM pulse signal and a second PWM pulse signal, the first PWM pulse signal and the second PWM pulse signal are signal-inverted, the first driving circuit corresponds to the first PWM pulse signal, and the second driving circuit corresponds to the second PWM pulse signal, so that the H-bridge circuit can share one PWM pulse signal for driving control of the first driving circuit and the second driving circuit. The first driving circuit includes NPN transistors Q3, Q4 and Q5. The base of the transistor Q3 is connected with the input end of the current detection circuit and the inverter, the emitter is grounded, and the collector is connected with the base of the MOS transistor Q4 and the first PWM pulse signal. The base of the transistor Q4 is connected with the collector of the MOS transistor Q3 and the first PWM pulse signal, the emitter is grounded, and the collector is connected with the H-bridge circuit and the power supply VCC. The base of the transistor Q5 is connected with the first PWM pulse signal, the emitter is grounded, and the collector is connected with the enable circuit and the H-bridge circuit. The second driving circuit includes NPN transistors Q10, Q11 and Q12. The base of the transistor Q10 is connected with the second PWM pulse signal, the emitter is grounded, and the collector is connected with the H-bridge circuit. The base of the transistor Q11 is connected with the second PWM pulse signal, the emitter is grounded, and the collector is connected with the power supply VCC and the H-bridge circuit. The base of the transistor Q12 is connected with the current detection circuit, the emitter is grounded, and the collector is connected with the second PWM pulse signal. The resistor R9 is a current-limiting resistor of the transistor Q5, and the resistor R10 prevents the base and the emitter of the transistor Q5 from being turned on. The resistor R5 is a current-limiting resistor of the base of the transistor Q3, the resistor R6 is a current-limiting resistor between the first PWM pulse signal PWM1 and GND, the resistor R7 is a current-limiting resistor of the base of the transistor Q4, the resistor R8 is a current-limiting resistor between the power supply VCC and GND, the resistor R12 is a driving resistor of the MOS transistor Q7, and the resistor R14 prevents the gate and the source of the Q7 from being mis-conducted. Similarly, the functions of the elements of the right driving circuit are the same as those of the left driving circuit.

[0035] As an optional implementation, the current detection circuit includes a comparator U2 and a current detection resistor R16 (with a resistance value in the milliohm range). One end of the current detection resistor R16 is connected to the comparator U2 and the H-bridge circuit, and the other end is grounded. The positive terminal of the comparator U2 is connected to the current detection resistor R16 and the H-bridge circuit, thus the positive terminal receives the voltage corresponding to the current detection resistor R16, and the negative terminal is connected to the reference voltage VREF. The reference voltage VREF is determined by the current flowing through the load and the resistance value of the current sampling resistor. The output terminal is connected to the input terminals of the first drive circuit, the second drive circuit, and the inverter. The overcurrent detection circuit also includes a capacitor C1 and a pull-up resistor R15. One end of the capacitor C1 is connected to the current detection resistor R16, and the other end is grounded to keep the sampling voltage of the current detection resistor R16 stable. One end of the pull-up resistor R15 is connected to the positive power supply terminal of the comparator U2, and the other end is connected to the output terminal of the comparator U2. When the circuit is working normally, when current flows through the load U3, a voltage drop will be generated across the current sensing resistor R16. If it is less than the reference voltage VREF, the comparator U2 will output a low level; if it is greater than the reference voltage VREF, the comparator U2 will output a high level.

[0036] The working process of this embodiment is as follows: ① Normal working state: During normal operation, current flows through R16. The positive input voltage collected by comparator U2 is less than the preset reference voltage, and the signal at pin 5 of the comparator output is low. Transistors Q3 and Q12 are not conducting. At this time, the first PWM pulse signal PWM1 and the second PWM pulse signal PWM2 are normally input to the first drive circuit and the second drive circuit. The output of comparator U2 becomes high after passing through inverter U1, and transistor Q2 conducts. The gate of MOSFET Q1 is grounded, forming a gate-source voltage difference, so transistor Q1 conducts, and the circuit is powered normally. Figure 2 As shown, when the first PWM pulse signal PWM1 outputs a low level and the second PWM pulse signal PWM2 outputs a high level, the first PWM pulse signal PWM1 is low, transistor Q5 is not turned on, the gate of MOSFET Q6 is floating, and the voltage is the same as the source, so MOSFET Q6 is not turned on; at the same time, transistor Q4 is not turned on, and the power supply VCC supplies power to the base of MOSFET Q7 after voltage division, so MOSFET Q7 is turned on. The second PWM pulse signal PWM2 is high, Q10 is turned on, the gate of MOSFET Q8 is grounded, forming a gate-source voltage difference, so MOSFET Q8 is turned on; at the same time, transistor Q11 is turned on, the power supply VCC is grounded through resistor R23, and the base of MOSFET Q9 has no driving voltage, so MOSFET Q9 is not turned on. Therefore, the current flow in the H-bridge circuit is from pin 2 of the load motor U3 to pin 1. Similarly, as Figure 3As shown, when the first PWM pulse signal PWM1 outputs high level and the second PWM pulse signal PWM2 outputs low level, the current flowing through the motor is from the pin 1 to the pin 2 of the load motor U3. Figure 4 As shown, the current flowing through the resistor R16 increases, the positive input voltage collected by the comparator U2 becomes larger, and when the set overcurrent protection value is reached, the positive input voltage of the comparator U2 is greater than the negative preset reference value, at this time, the comparator outputs high level, the triode Q3 and the triode Q12 are turned on, the first PWM pulse signal PWM1 is grounded through the resistor R6, the second PWM pulse signal PWM2 is grounded through the resistor R25, and the driving signal is pulled low. The triode Q5 is not conductive, so the MOS tube Q6 is not conductive; the triode Q10 is not conductive, so the MOS tube Q8 is not conductive; the triode Q4 is not conductive, so the MOS tube Q7 is conductive; the triode Q11 is not conductive, so the MOS tube Q9 is conductive; the MOS tube Q7 and the MOS tube Q9 form a loop with GND to consume the remaining energy in the circuit. The high level output by the comparator U2 becomes low level after the inverter U1, the triode Q2 is not conductive, the MOS tube Q1 base is suspended, the MOS tube Q1 is not conductive, the circuit power is cut off, the driving signal is turned off, and the overcurrent protection is performed. Until the current returns to the normal value, the comparator U2 outputs low level, the MOS tube Q1 is powered on, the driving signal is turned on, and the circuit resumes work.

[0037] The embodiment is only a specific example, and does not indicate that the utility model is in this way.

[0038] Embodiment two:

[0039] A power electronic device includes a MOS tube overcurrent protection circuit in embodiment one. After the power electronic device adopts the MOS tube overcurrent protection circuit in embodiment one, the accuracy and sensitivity of overcurrent detection are ensured, sufficient protection performance is provided for the H-bridge circuit and the power electronic device, the number of elements of the power electronic device is reduced, and the compactness and maintainability of the circuit are improved.

[0040] The above is only a preferred embodiment of the utility model, and those skilled in the art know that various changes or equivalent replacements can be made to the features and embodiments without departing from the spirit and scope of the utility model. In addition, the features and embodiments can be modified to adapt to specific conditions and materials under the guidance of the utility model without departing from the spirit and scope of the utility model. Therefore, the utility model is not limited by the specific embodiments disclosed here, and all embodiments falling within the scope of the claims of the application belong to the protection scope of the utility model.

Claims

1. A MOSFET overcurrent protection circuit, characterized in that, The overcurrent protection circuit comprises an enabling circuit, a first driving circuit, a second driving circuit and a current detection circuit; the enabling circuit is connected with a power supply VCC and controls power supply of an H-bridge circuit through level signal change; the first driving circuit and the second driving circuit are both connected with the H-bridge circuit and make different MOS transistors in the H-bridge circuit conduct or cut off through PWM pulse signals; the current detection circuit is connected with the first driving circuit, the second driving circuit, the H-bridge circuit and the enabling circuit and is used for detecting current size output by the H-bridge circuit to a load; if overcurrent occurs, the enabling circuit is cut off to perform overcurrent protection.

2. The MOSFET overcurrent protection circuit of claim 1, wherein, The overcurrent protection circuit further comprises an inverter, the inverter reverses polarity of an input level signal, an input end of the inverter is connected with the first driving circuit, the second driving circuit and the current detection circuit, and an output end is connected with the enabling circuit.

3. The MOSFET overcurrent protection circuit of claim 2, wherein: The enabling circuit comprises a P-type MOS transistor Q1 and an NPN-type triode Q2; a source of the MOS transistor Q1 is connected with the power supply VCC, a drain is connected with the H-bridge circuit, and a gate is connected with a collector of the triode Q2; an emitter of the triode Q2 is connected with ground, and a base is connected with the inverter.

4. The MOSFET overcurrent protection circuit of claim 3, wherein: The enabling circuit further comprises a resistor R1, a resistor R2, a resistor R3, a resistor R4 and a voltage stabilizing diode D1; the voltage stabilizing diode D1 is used for voltage stabilizing of source-gate voltage of the MOS transistor Q1; one end of the resistor R2 is connected with the power supply VCC and the source of the MOS transistor Q1, and the other end is connected with the resistor R4 and the gate of the MOS transistor Q1; one end of the resistor R4 is connected with the resistor R2 and the gate of the MOS transistor Q1, and the other end is connected with the collector of the triode Q2; one end of the resistor R1 is connected with the inverter, and the other end is connected with the resistor R3 and the base of the triode Q2; one end of the resistor R3 is connected with the resistor R1 and the base of the triode Q2, and the other end is connected with ground.

5. The MOSFET overcurrent protection circuit of claim 2, wherein: The PWM pulse signal comprises a first PWM pulse signal and a second PWM pulse signal, the first PWM pulse signal and the second PWM pulse signal are signal inverses, the first driving circuit corresponds to the first PWM pulse signal, and the second driving circuit corresponds to the second PWM pulse signal.

6. The MOSFET overcurrent protection circuit of claim 5, wherein, The first driving circuit comprises an NPN-type triode Q3, an NPN-type triode Q4 and an NPN-type triode Q5; a base of the triode Q3 is connected with an input end of the current detection circuit and the inverter, an emitter is connected with ground, and a collector is connected with a base of the MOS transistor Q4 and the first PWM pulse signal; a base of the triode Q4 is connected with a collector of the MOS transistor Q3 and the first PWM pulse signal, an emitter is connected with ground, and a collector is connected with the H-bridge circuit and the power supply VCC; a base of the triode Q5 is connected with the first PWM pulse signal, an emitter is connected with ground, and a collector is connected with the enabling circuit and the H-bridge circuit.

7. The MOSFET overcurrent protection circuit of claim 5, wherein: The second drive circuit comprises NPN type triode Q10, NPN type triode Q11, NPN type triode Q12; the base of the triode Q10 is connected with the second PWM pulse signal, the emitter is grounded, and the collector is connected with the H bridge circuit; the base of the triode Q11 is connected with the second PWM pulse signal, the emitter is grounded, and the collector is connected with the power supply VCC and the H bridge circuit; the base of the triode Q12 is connected with the current detection circuit, the emitter is grounded, and the collector is connected with the second PWM pulse signal.

8. The MOSFET overcurrent protection circuit of any one of claims 2-7, wherein, The current detection circuit comprises a comparator U2 and a current detection resistor R16; one end of the current detection resistor R16 is connected with the comparator U2 and the H bridge circuit, and the other end is grounded; the positive electrode of the comparator U2 is connected with the current detection resistor R16 and the H bridge circuit, the negative electrode is connected with a reference voltage VREF, and the output end is connected with the input end of the first drive circuit, the second drive circuit and the inverter.

9. The MOSFET overcurrent protection circuit of claim 8, wherein, The overcurrent detection circuit further comprises a capacitor C1 and a pull-up resistor R15; one end of the capacitor C1 is connected with the current detection resistor R16, and the other end is grounded, for keeping the sampling voltage of the current detection resistor R16 stable; one end of the pull-up resistor R15 is connected with the positive power supply end of the comparator U2, and the other end is connected with the output end of the comparator U2.

10. A power electronic device, characterized by The power electronic device comprises the MOS tube overcurrent protection circuit according to any one of claims 1-9.

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