Protection circuit applied to MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor), MOSFET circuit and chip
Through the integrated overcurrent and overvoltage protection circuit, the rapid response and collaborative protection of the MOSFET protection circuit are achieved, which solves the problems of slow response speed and lack of coordination of independent modules in the prior art, and improves the reliability and stability of the system.
Patent Information
- Application Number
- CN202510573345.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-06
- Publication Date
- 2025-08-01
AI Technical Summary
The existing MOSFET protection circuit has slow response speed, the independent and lack of coordination of protection modules, lack of gradient protection and pre-protection, and high power consumption, resulting in insufficient system reliability and stability.
The integrated overcurrent overvoltage protection circuit is adopted, and the overvoltage protection unit is adjusted in parallel with the overcurrent protection unit to form a dual closed-loop dynamic adjustment mechanism, combining the transient overvoltage acceleration protection circuit and adaptive charge pump power supply, gradient response and pre-protection are achieved, and the threshold is dynamically adjusted to adapt to different load conditions.
It improves the response speed and coordination of the MOSFET protection circuit, reduces power consumption, enhances the adaptability and reliability of the system, avoids sudden current changes caused by hard shutdown, and ensures the continuous working ability of the circuit.
Smart Images
Figure CN120415092A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of circuit design, and particularly to a protection circuit for MOSFET, a MOSFET circuit and a chip. Background Art
[0002] With the continuous progress of power electronics technology, various power conversion and control systems are widely used in industrial, commercial and household environments. For example, direct current based on a battery pack drives a motor to rotate through a power switch, an H-bridge or an inverter circuit. The MOS transistor is a core device for constructing a power switch and an H-bridge circuit, and it faces the risk of failure or damage caused by overvoltage and overcurrent impacts. For example, during high-voltage and high-frequency switching processes, the inductive load of the motor, the parasitic inductance / stray inductance of the circuit, etc. will cause the problem of turn-off overvoltage, and the damage of the MOS transistor will lead to the malfunction of the entire system. Therefore, designing a reliable overcurrent and overvoltage protection circuit is crucial for improving the reliability and safety of the system.
[0003] Traditional overvoltage and overcurrent protection methods have problems such as slow response speed, independent protection modules, lack of coordination, gradient protection, pre-protection and high power consumption. Taking a motor control circuit as an example, since the instantaneous current is large when the motor starts, false protection is likely to occur when setting the threshold according to the general long-term working safety current. Overcurrent protection measures, such as thermistors and current limiters, also face problems such as long response time and difficult to accurately set the protection threshold, seriously affecting the continuity and stability of system operation. With the development of electronic products towards miniaturization and lightweight, it is necessary to develop an overcurrent and overvoltage protection scheme with high reliability, certain adaptability and flexibility in a limited space. Summary of the Invention
[0004] Aiming at the deficiencies in the prior art, the present invention provides a protection circuit for MOSFET, which improves the problems of slow response speed of the overcurrent and overvoltage protection circuit in the prior art, independent protection modules, lack of coordination and gradient protection, lack of pre-protection, high power consumption, etc. At the same time, the present invention provides a MOSFET circuit and a chip with high-efficiency protection and low cost.
[0005] An embodiment of the present invention provides a circuit for integrated overcurrent and overvoltage protection for MOS, including an overvoltage protection unit and an overcurrent protection unit; the overvoltage protection unit includes an overvoltage monitoring circuit and a triode overvoltage regulation circuit; the overcurrent protection unit includes an overcurrent detection circuit and a triode overcurrent regulation circuit; the regulation action ends of the triode overvoltage regulation circuit and the triode overcurrent regulation circuit are connected in parallel between the gate and the source of the MOSFET to be protected;
[0006] The overvoltage monitoring circuit is used to monitor the source voltage of the MOSFET to be protected. When the monitored voltage exceeds the set threshold, it triggers the triode overvoltage regulation circuit to reduce the voltage at the regulation action end, so as to limit the conduction of the MOSFET to be protected.
[0007] The overcurrent monitoring circuit is used to monitor the magnitude of the current in the source-drain circuit of the MOSFET to be protected. When the monitored current exceeds the set threshold, it triggers the triode overcurrent regulation circuit to reduce the voltage at the regulation action end, so as to limit the conduction of the MOSFET to be protected.
[0008] Furthermore, the overvoltage monitoring circuit includes a first voltage-dividing resistor network and a zener diode D1; the stable operating voltage of the zener diode D1 is greater than the voltage-divided output voltage of the first voltage-dividing resistor network for the source voltage of the MOSFET to be protected, and not greater than the set overvoltage protection threshold voltage.
[0009] Furthermore, the triode overvoltage regulation circuit includes a PNP triode, a resistor R2 and a resistor R5; wherein, the resistor R2 and the resistor R5 are connected in series to form a second resistor voltage-dividing network, and the second resistor voltage-dividing network is integrally connected between the source of the MOSFET to be protected and the reference power ground terminal; the connection terminal of the resistor R2 and the resistor R5 is connected to the gate of the MOSFET to be protected and the collector of the PNP triode; the emitter of the PNP triode is connected to the source of the MOSFET to be protected.
[0010] Furthermore, it also includes a transient overvoltage acceleration protection circuit, and the transient overvoltage acceleration protection circuit is connected in parallel with the resistor R2; the transient overvoltage acceleration protection circuit is composed of one of a capacitor, or a series circuit of a capacitor and a resistor, or a transient suppression diode D2; wherein, the cathode of the transient suppression diode D2 is connected to the source of the MOSFET to be protected, and the anode is connected to the gate of the MOSFET to be protected.
[0011] Furthermore, the overcurrent monitoring circuit includes a comparator and a MOSFET current feedback circuit; one input of the comparator is connected to a reference voltage, and the other input of the comparator is connected to the output of the MOSFET current feedback circuit; the MOSFET current feedback circuit includes a resistor sampling circuit or a Hall current sensing circuit.
[0012] Furthermore, it also includes a series capacitor circuit and a charge pump circuit; the series capacitor circuit includes at least 3 series capacitors, and the series capacitor circuit is integrally connected between the source of the MOSFET to be protected and the reference power ground terminal; the connection points of the 3 series capacitors respectively correspond to the input terminal and the enable terminal of the charge pump circuit, and the output of the charge pump circuit is used to provide power supply for the comparator.
[0013] Further, it further includes a conversion circuit, which obtains the magnitude of the current of the source and drain circuits of the MOSFET to be protected and converts and outputs it as the enable voltage of the charge pump circuit; the threshold voltage at which the conversion circuit triggers the charge pump circuit to enable operation is not higher than the overcurrent threshold voltage of the MOSFET to be protected and is greater than the normal voltage division value of the source voltage of the MOSFET corresponding to the connection ends of the two series capacitors on the low side in the series capacitor circuit.
[0014] Further, the output of the conversion circuit is also used to clamp the overvoltage protection threshold of the overvoltage monitoring circuit. Correspondingly, the output voltage of the conversion circuit is less than the protection threshold of the overvoltage monitoring circuit to achieve pre-protection of the voltage overshoot during the switching operation of the MOSFET to be protected in the overcurrent state.
[0015] The present invention also provides a MOSFET circuit, which includes a switching MOSFET and a protection circuit for MOSFET as described above, or further includes an H-bridge circuit; the protection circuit for MOSFET is used for overvoltage and overcurrent protection of the switching MOSFET; the switching MOSFET is used to achieve controllable conduction of the main circuit.
[0016] The present invention also provides a chip, which integrates a protection circuit for MOSFET or a MOSFET circuit as described above.
[0017] Aiming at the technical defects existing in the existing MOSFET protection technologies, such as slow response speed, lack of coordination in the independent operation of protection modules, and insufficient dynamic threshold adjustment ability, the present invention proposes an integrated overcurrent and overvoltage coordinated protection circuit. This solution realizes the gradient response and pre-protection of voltage / current abnormal states within a single circuit framework by constructing a multi-level linkage protection architecture. The main improvements include:
[0018] 1. Double-closed-loop dynamic regulation mechanism:
[0019] Through the parallel adjustment structure of the overvoltage protection unit and the overcurrent protection unit, a two-way voltage adjustment path is formed between the gate and source of the MOSFET. When an abnormality in the source voltage or drain current is detected, the triode adjustment circuit realizes dynamic adjustment of the conduction impedance by changing the gate drive voltage, rather than the direct turn-off operation in the traditional solution, effectively suppressing the transient impact while maintaining the continuous operation ability of the circuit.
[0020] 2. Transient overvoltage acceleration protection circuit:
[0021] A transient response branch composed of a transient voltage suppression diode (TVS) and an RC network is connected in parallel to the conventional voltage-dividing resistor network. The response time of this branch to nanosecond-level voltage spikes is faster than that of the traditional voltage regulator diode scheme. At the moment when the MOSFET is turned off, the gate charge is quickly discharged through the avalanche breakdown characteristic of the TVS, and the gate-source voltage is clamped within the safety threshold. The transient overvoltage acceleration protection circuit can effectively compensate for the reaction speed of the triode overvoltage regulation circuit and is applicable to a wider range of scenarios.
[0022] S3. Have an adaptive charge pump power supply:
[0023] A new power supply architecture that combines a series capacitor voltage-dividing network and a conversion circuit to work together. Under normal operating conditions, a stable operating voltage is provided for the comparator through the charge distribution effect of the series capacitor; when an overcurrent omen is detected, the conversion circuit activates the charge pump in advance to establish an isolated power supply to ensure that the protection circuit can still work reliably when the supply voltage drops.
[0024] S4. Threshold coupling regulation:
[0025] The overvoltage protection unit and the overcurrent protection unit achieve threshold parameter coupling through the conversion circuit. When the overcurrent protection is triggered, the conversion circuit synchronously adjusts the overvoltage protection threshold to form a dynamic protection range, providing pre-protection for the voltage overshoot during the switching operation under large current and effectively suppressing the voltage overshoot caused by the switching operation. When the current does not reach the overcurrent threshold, the charge pump circuit has no enabled output and the comparator has no power supply, which is more energy-efficient than the traditional scheme. By automatically adjusting the overvoltage protection threshold and the overcurrent protection level according to the load current, the adaptability of the system is improved. Description of the Drawings
[0026] Figure 1 It is a circuit schematic diagram of a protection circuit applied to a MOSFET provided in Embodiment 1 of the present invention;
[0027] Figure 2 It is a circuit schematic diagram provided in Embodiment 2 of the present invention;
[0028] Figure 3 It is a circuit schematic diagram provided in Embodiment 3 of the present invention. Detailed Embodiments
[0029] Next, the technical solutions in the embodiments of the present application will be described with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments.
[0030] Hereinafter, terms such as "second", "first", etc. are only used for convenience of description and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "second", "first", etc. may explicitly or implicitly include one or more of such features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.
[0031] In the embodiments of the present application, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. For example, "connection" may be a fixed connection, a detachable connection, or integrated; it may be directly connected or indirectly connected through an intermediate medium. In addition, the term "coupled" may be a direct electrical connection or an indirect electrical connection through an intermediate medium. The term "contact" may be direct contact or indirect contact through an intermediate medium.
[0032] In the embodiments of the present application, "and / or" describes the association relationship of associated objects and indicates that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone, where A and B may be singular or plural. The character " / " generally represents an "or" relationship between the front and rear associated objects.
[0033] Embodiment 1
[0034] This embodiment combines one specific application of a MOSFET and proposes an over-current and over-voltage protection circuit applied to a MOSFET. The circuit structure of this embodiment is as Figure 1As shown, where Q2 is the P-type MOSFET to be protected, the overcurrent and overvoltage protection circuit includes an overvoltage protection unit and an overcurrent protection unit. The overvoltage protection unit includes an overvoltage monitoring circuit and a triode overvoltage regulation circuit; the overcurrent protection unit includes an overcurrent detection circuit and a triode overcurrent regulation circuit; the overvoltage monitoring circuit includes a first voltage-dividing resistor network composed of resistor R1 and resistor R4, and a zener diode D1; the stable operating voltage of the zener diode D1 is greater than the voltage-divided output voltage of the first voltage-dividing resistor network for the source voltage of the MOSFET to be protected, and not greater than the set overvoltage protection threshold voltage. Resistor R1 is used to limit the base current and prevent excessive base current from damaging triode Q3. The resistance value of resistor R1 needs to satisfy: R1 = (VCC - VZ) / IB to ensure the normal operation of the circuit, where VZ is the breakdown voltage of the zener diode D1 and IB is the base current of the triode required for the overvoltage regulation circuit. Resistor R4 divides the voltage to ensure that the zener diode D1 reliably breaks down when VCC connected to the source of the MOSFET reaches the set threshold. When the zener diode D1 is operating normally, it is in a reverse-biased state and hardly conducts. When VCC is low, the voltage across the zener diode D1 is not enough to cause it to break down, so it does not conduct at this time. The overall voltage division of VCC by resistor R1 and resistor R4 is output to the triode overvoltage regulation circuit; the triode overvoltage regulation circuit includes a PNP triode Q3, resistor R2, and resistor R5; among them, resistor R2 and resistor R5 are connected in series to form a second voltage-dividing resistor network, and the second voltage-dividing resistor network is integrally connected between the source of the MOSFET Q2 to be protected and the reference power ground terminal; the connection end of resistor R2 and resistor R5 is connected to the gate of the MOSFET Q2 to be protected and the collector of the PNP triode Q3; the emitter of the PNP triode Q3 is connected to the source of the MOSFET Q2 to be protected. The two ends of the emitter and collector of the PNP triode Q3 serve as the adjustment action end of the triode regulation circuit. When the monitored voltage exceeds the set threshold, the triode overvoltage regulation circuit is triggered to reduce the voltage at the adjustment action end to limit the conduction of the MOSFET Q2 to be protected. As an embodiment, to improve the protection of the overvoltage protection circuit against transient overshoot voltage, a transient suppression diode D2 is connected in parallel with resistor R2; as an embodiment, a capacitor (not shown in the figure) is connected in parallel with resistor R2. Specifically, when in use, the transient suppression diode D2 and the capacitor can be selected to be used simultaneously.
[0035] The overcurrent monitoring circuit includes a comparator U1 and a MOSFET current feedback circuit; one input of the comparator U1 is connected to a reference voltage VREF, and the other input of the comparator U1 is connected to the output of the MOSFET current feedback circuit; the output of the comparator U1 triggers the triode overcurrent regulation circuit to change the voltage between the gate and source of the MOSFET to be protected. The MOSFET current feedback circuit includes a resistor sampling circuit or a Hall current sensing circuit. In this embodiment, a low-resistance resistor R9 is used as the sampling resistor. The triode current regulation circuit includes a resistor R6, a resistor R3, and an NPN triode Q1. The advantage of the resistor sampling circuit is good real-time performance and low power consumption under the condition of a generally small working current. However, its disadvantage is that it is easily damaged by instantaneous overload. In contrast, the Hall current sensing circuit scheme has better overload capacity. If the Hall current sensing circuit scheme is used, the input connected to the comparator can be selected according to the sensor type, including being connected after driving by a linear amplifier circuit or directly connecting the Hall current sensing circuit to the comparator U1. When an overcurrent occurs due to an abnormal circuit, the current flowing through the resistor R9 increases, and the positive input voltage collected by the comparator U1 becomes larger. When the set overcurrent protection value is reached, the positive input voltage of U1 is greater than the negative preset reference value. At this time, the comparator outputs a high level. The triode Q1 conducts, and the source and gate of the MOS transistor Q2 are connected, and the MOS is turned off. The VCC voltage cannot be supplied to the H bridge, and overcurrent protection is performed in a timely manner. Thus, through the double closed-loop control of the overvoltage protection unit and the overcurrent protection unit, and by dynamically adjusting the voltage between the gate and source, soft turn-off is achieved, and the on-resistance is gradually reduced instead of hard cutting. This progressive turn-off can avoid secondary overcurrent caused by current mutation (di / dt), and the MOSFET is effectively protected. Additionally, as an embodiment, the reference voltage connected to the comparator input is implemented by an adjustable reference source to construct a dynamic overcurrent threshold reference. The adjustable reference source can be TL431 or a DAC to achieve dynamic threshold adjustment.
[0036] Embodiment 2
[0037] The difference between this embodiment and Embodiment 1 is that it further includes a series capacitor circuit and a charge pump circuit; the series capacitor circuit includes at least 3 series capacitors, such as Figure 2As shown, the series capacitor circuit of this embodiment includes a resistor R7, capacitors C1 - C3, and a resistor R8 connected in series in sequence. Among them, the series capacitor circuit is integrally connected between the source of the MOSFET to be protected and the reference power ground terminal. Resistors R7 and R8 limit the charging current of capacitors C1 - C3, avoiding excessive current caused by instantaneous voltage changes that may burn out the capacitors. In addition, their symmetrical design helps to set the potential between capacitors C1 - C3. The connection point between capacitor C1 and capacitor C2 is connected to the input terminal of the charge pump circuit, and the connection point between capacitor C2 and capacitor C3 is connected to the enable terminal of the charge pump circuit shown. The output of the charge pump circuit is used to provide power supply for the comparator. The charge pump circuit of this embodiment uses a low-noise, constant-frequency (1.2 MHz) switched-capacitor voltage multiplier TX4310B, which can generate a stable output voltage from an input of 1.8V to 5V. The series capacitor circuit has an overall effect of filtering the VCC power supply in the Figure 2 structure, has a certain anti-interference effect. And due to the presence of resistors R7 and R8 and the influence of capacitor voltage division in the power supply filtering, when the MOSFET Q2 turns on faster than the charge pump circuit can establish a power supply for the comparator U1, the current monitoring under the large current impact brought by the subsequent reactive load during the switching of the MOSFET Q2 is thus ignored. Another difference between this embodiment and Embodiment 1 is that the overvoltage protection priority of this embodiment is higher than the overcurrent protection, and because the current monitoring circuit is not in a continuous working state, there is a certain power consumption saving. For the working voltage of the charge pump circuit, it can be less than the threshold voltage of the current protection to facilitate the timely construction of an effective current monitoring environment.
[0038] Embodiment 3
[0039] The difference between this embodiment and Embodiment 2 is that it further includes a conversion circuit. The conversion circuit obtains the magnitude of the current flowing through the source-drain circuit of the MOSFET Q2 to be protected and converts it into an enable voltage for the charge pump circuit; the threshold voltage at which the conversion circuit triggers the charge pump circuit to enable operation is not higher than the overcurrent threshold voltage of the MOSFET to be protected and is greater than the normal voltage division value of the source voltage of the MOSFET corresponding to the connection end of the two series capacitors on the low side in the series capacitor circuit. Specifically, the conversion circuit can be an amplification circuit, that is, an electrical signal or a voltage signal corresponding to the electrical signal is amplified into a voltage signal matching the charge pump circuit, specifically not limited to isolation amplification or non-isolation amplification, linear amplification or non-linear amplification. For example, non-linear amplification can be a piecewise amplification circuit. In this embodiment, an optocoupler isolation circuit U3 is used, in which the optocoupler diode is connected in parallel with the sampling resistor. Because the resistance value of the sampling resistor is relatively low, under normal circumstances, the voltage on the sampling resistor is small and the optocoupler diode does not work. When the current flowing through the sampling resistor is large and the voltage drop generated is greater than the voltage drop of the optocoupler diode, the optocoupler diode conducts, a part of the current flows through the optocoupler diode, the optocoupler triode conducts, and the resistor R11 is connected to the power supply voltage VCC through the optocoupler triode and the resistor R12. Through resistance value selection and parameter matching, the conversion of the current threshold can be realized, and the upper-end voltage of the resistor R11 is used for the enable trigger operation of the charge pump circuit.
[0040] Among them, both the diode D3 and the diode D4 use Schottky diodes, and the low-voltage-drop diodes contribute to achieving voltage isolation and parameter matching.
[0041] As an embodiment, the output of the conversion circuit is also used to clamp the overvoltage protection threshold of the overvoltage monitoring circuit, that is, the cathode of D4 is connected to the cathode of D2 (not shown in the figure). Correspondingly, the output voltage of the conversion circuit is less than the protection threshold of the overvoltage monitoring circuit to achieve pre-protection of voltage overshoot during the switching action of the MOSFET to be protected in the overcurrent state. This embodiment realizes the threshold coupling of overcurrent protection and overvoltage protection through the conversion circuit and has four technical advantages:
[0042] 1. Dynamic threshold adjustment: The conversion circuit dynamically adjusts the overvoltage protection threshold according to the real-time current value, reduces the overvoltage protection sensitivity in advance during the overcurrent omen period, and effectively suppresses the voltage overshoot caused by the switching action (such as the Vds spike caused by di / dt);
[0043] 2. Energy optimization management: The charge pump is only started when the current is close to the threshold, reducing the static power consumption compared with the traditional continuous power supply scheme.
[0044] 3. Enhanced fault isolation: The optocoupler isolation design electrically isolates the main power loop from the protection control loop, avoiding interference to the control circuit caused by large current impacts.
[0045] 4. Overcurrent protection and overvoltage protection coordination: Enable the independent protection circuits to cooperate when approaching the protection threshold, improve the protection efficiency, avoid hard turn-off, and make the circuit operate more smoothly and reliably.
[0046] Embodiment 4
[0047] This embodiment provides a MOSFET circuit, which includes a switching MOSFET and a protection circuit for MOSFET corresponding to Embodiments 1-3. The protection circuit for MOSFET is used for overvoltage and overcurrent protection of the switching MOSFET. Among them, the switching MOSFET is the Figures 1-3 P-type MOSFET Q2 in. As an embodiment, Figures 1-3 The H-bridge circuit in is used as a load driving circuit, which is connected to an external load. The external load is connected in series with the switching MOSFET through the driving end of the H-bridge. The external load includes Figures 1-3 Resistor R10 and inductor L1 in, and can also be other load circuits. The switching MOSFET is used to achieve controllable conduction of the main circuit.
[0048] This embodiment has the ability to adapt to the load: Through dynamic threshold adjustment, it can automatically adapt to a wide range of load currents, avoid false triggering or protection blind spots caused by fixed thresholds, and the protection circuit has a small area, which is suitable for high-density PCB layout.
[0049] Embodiment 5
[0050] This embodiment provides a chip integrated with the protection circuit for MOSFET or the MOSFET circuit mentioned in the above embodiments. This embodiment has a high integration degree, outstanding cost-effectiveness compared with discrete components, and high circuit reliability.
[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.
Claims
1. A protection circuit applied to a MOSFET, characterized in that, It includes an overvoltage protection unit and an overcurrent protection unit; the overvoltage protection unit includes an overvoltage monitoring circuit and a triode overvoltage regulation circuit; the overcurrent protection unit includes an overcurrent detection circuit and a triode overcurrent regulation circuit; the regulation action ends of the triode overvoltage regulation circuit and the triode overcurrent regulation circuit are connected in parallel between the gate and the source of the MOSFET to be protected; The overvoltage monitoring circuit is used to monitor the source voltage of the MOSFET to be protected. When the monitored voltage exceeds the set threshold, it triggers the triode overvoltage regulation circuit to change the voltage at the regulation action end to limit the conduction of the MOSFET to be protected; The overcurrent monitoring circuit is used to monitor the magnitude of the current in the source-drain circuit of the MOSFET to be protected. When the monitored current exceeds the set threshold, it triggers the triode overcurrent regulation circuit to change the voltage at the regulation action end to limit the conduction of the MOSFET to be protected.
2. The protection circuit for MOSFET according to claim 1, characterized in that, The overvoltage monitoring circuit includes a first voltage division resistor network and a zener diode D1; the stable operating voltage of the zener diode D1 is greater than the voltage division output voltage of the first voltage division resistor network for the source voltage of the MOSFET to be protected and not greater than the set overvoltage protection threshold voltage.
3. The protection circuit for MOSFET according to claim 1, characterized in that, The triode overvoltage regulation circuit includes a PNP triode, a resistor R2, and a resistor R5; among them, the resistor R2 and the resistor R5 are connected in series to form a second resistor voltage division network, and the second resistor voltage division network is integrally connected between the source of the MOSFET to be protected and the reference power ground terminal; the connection end of the resistor R2 and the resistor R5 is connected to the gate of the MOSFET to be protected and the collector of the PNP triode; the emitter of the PNP triode is connected to the source of the MOSFET to be protected.
4. The protection circuit for MOSFET according to claim 3, characterized in that, It also includes a transient overvoltage acceleration protection circuit, and the transient overvoltage acceleration protection circuit is connected in parallel with the resistor R2; the transient overvoltage acceleration protection circuit is composed of one of a capacitor, or a series circuit of a capacitor and a resistor, or a transient suppression diode D2; among them, the cathode of the transient suppression diode D2 is connected to the source of the MOSFET to be protected, and the anode is connected to the gate of the MOSFET to be protected.
5. A protection circuit applied to a MOSFET according to claim 1, characterized in that, The overcurrent monitoring circuit includes a comparator and a MOSFET current feedback circuit; one input of the comparator is connected to a reference voltage, and the other input of the comparator is connected to the output of the MOSFET current feedback circuit; the MOSFET current feedback circuit includes a resistor sampling circuit or a Hall current sensing circuit; the output of the comparator triggers the triode overcurrent regulation circuit to change the voltage between the gate and the source of the MOSFET to be protected.
6. The protection circuit applied to a MOSFET according to claim 5, characterized in that, It also includes a series capacitor circuit and a charge pump circuit; the series capacitor circuit includes at least 3 series capacitors, and the series capacitor circuit is integrally connected between the source of the MOSFET to be protected and the reference power ground terminal; the connection points of the 3 series capacitors respectively correspond to the input end and the enable end of the charge pump circuit, and the output of the charge pump circuit is used to provide power supply for the comparator.
7. The protection circuit applied to a MOSFET according to claim 6, wherein, It also includes a conversion circuit which obtains the magnitude of the current flowing through the source and drain circuits of the MOSFET to be protected and converts and outputs it as the enable voltage of the charge pump circuit; the threshold voltage at which the conversion circuit triggers the charge pump circuit to enable operation is not higher than the overcurrent threshold voltage of the MOSFET to be protected and is greater than the normal voltage division value corresponding to the source voltage of the MOSFET at the connection ends of the two series capacitors on the low side in the series capacitor circuit.
8. The protection circuit for a MOSFET according to claim 7, characterized in that, The output of the conversion circuit is also used to clamp the overvoltage protection threshold of the overvoltage monitoring circuit. Correspondingly, the output voltage of the conversion circuit is less than the protection threshold of the overvoltage monitoring circuit to achieve pre-protection of the voltage overshoot during the switching action of the MOSFET to be protected in an overcurrent state.
9. A MOSFET circuit, characterized in that, It includes a switching MOSFET and a protection circuit for MOSFET as described in any one of claims 1-8, or may also include an H-bridge circuit; the protection circuit for MOSFET is used for overvoltage and overcurrent protection of the switching MOSFET; the switching MOSFET is used to achieve controllable conduction of the main circuit.
10. A chip, characterized in that: Integrated with a protection circuit for MOSFET as described in any one of claims 1-8 or a MOSFET circuit as described in claim 9.