Switch tube protection circuit and drive circuit

Abstract

The present application relates to a switching transistor protection circuit and a driving circuit. The switching transistor protection circuit includes an integration loop, a control switch, a voltage regulator diode D3, and a diode D4. The integration loop is connected to a control signal input terminal, the cathode of the voltage regulator diode D3, and the anode of the diode D4. The anode of the voltage regulator diode D3 is connected to the control terminal of the control switch, and the cathode of the diode D4 is connected to the first end of the switching transistor. The first end of the control switch is connected to the control terminal of the switching transistor, and the second end of the control switch is grounded. The integration loop is configured to pull down the potential of the control terminal of the control switch and, when the switching transistor is overcurrent, raise the potential of the control terminal of the control switch to turn on the control switch, thereby turning off the switching transistor to achieve the purpose of overcurrent protection. Compared with the traditional switching transistor protection method, it is not restricted by the chip to affect the response speed, improves the protection timeliness, and reduces the risk of burning the subsequent chip or circuit.

Description

Technical Field

[0001] This application relates to the technical field of protection circuits, and particularly to a switching transistor protection circuit and a driving circuit. Background Art

[0002] In common control circuits and switching power supply circuits, the overvoltage or overcurrent protection of high-power semiconductor devices such as switching transistors is usually achieved by inputting the protection pin signal of a PWM chip. The traditional switching transistor protection method is limited by the parameters of the chip itself, etc., with a slow response speed and sluggish operation. There may be a risk of untimely protection for currents that increase too quickly in case of short circuit, resulting in the burnout of the subsequent chip or circuit. Summary of the Invention

[0003] Based on this, in view of the problem of untimely protection in the traditional switching transistor protection method, it is necessary to provide a switching transistor protection circuit and a driving circuit, which can achieve the effect of improving the timeliness of protection.

[0004] A switching transistor protection circuit includes an integration circuit, a control switch, a zener diode D3, and a diode D4. The integration circuit is connected to the control signal input terminal, the cathode of the zener diode D3, and the anode of the diode D4. The anode of the zener diode D3 is connected to the control terminal of the control switch, and the cathode of the diode D4 is connected to the first end of the switching transistor. The first end of the control switch is connected to the control terminal of the switching transistor, and the second end of the control switch is grounded. The integration circuit is configured to pull down the potential of the control terminal of the control switch and raise the potential of the control terminal of the control switch when the switching transistor is overcurrent, so as to turn on the control switch.

[0005] In one embodiment, the integration circuit includes a resistor R1 and a capacitor C1. The resistor R1 and the capacitor C1 are connected in series, and the common terminal is connected to the cathode of the zener diode D3 and the anode of the diode D4. The other end of the resistor R1 is connected to the control signal input terminal, and the other end of the capacitor C1 is grounded.

[0006] In one embodiment, the switching transistor protection circuit further includes a diode D1. The diode D1 is connected in parallel with the resistor R1, and the anode of the diode D1 is connected to the common terminal of the resistor R1 and the capacitor C1.

[0007] In one embodiment, the switching transistor protection circuit further includes a diode D2. The common terminal of the resistor R1 and the capacitor C1 is connected to the zener diode D3 through the diode D2, and the cathode of the diode D2 is connected to the cathode of the zener diode D3.

[0008] In one embodiment, the switch tube protection circuit further includes a resistor R2. One end of the resistor R2 is connected to the control signal input terminal, and the other end of the resistor R2 is connected to the control end of the switch tube.

[0009] In one embodiment, the switch tube protection circuit further includes a resistor R3. One end of the resistor R3 is connected to the control end of the control switch, and the other end of the resistor R3 is grounded.

[0010] In one embodiment, the switch tube protection circuit further includes a display circuit connected to the first end of the switch tube.

[0011] In one embodiment, the switch tube protection circuit further includes an alarm circuit connected to the first end of the control switch.

[0012] In one embodiment, the switch tube is a MOS tube, and the control switch is a triode.

[0013] A circuit device includes a switch tube and the above-mentioned switch tube protection circuit.

[0014] When the above-mentioned switch tube protection circuit and the drive circuit are in normal operation of the switch tube, the integration loop pulls down the potential of the control end of the control switch to prevent the mis-turn-on of the control switch. When the switch tube has an overcurrent, the integration loop raises the potential of the control end of the control switch to turn on the control switch, thereby turning off the switch tube, achieving the purpose of overcurrent protection. Compared with the traditional switch tube protection method, it is not restricted by the chip to affect the response speed, improves the protection timeliness, and reduces the risk of burning the subsequent chip or circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a schematic structural diagram of the switch tube protection circuit in one embodiment;

[0016] Figure 2 is a schematic diagram of the drive waveform when the circuit is in normal operation in one embodiment;

[0017] Figure 3 is a schematic diagram of the drive waveform when the circuit has overcurrent protection in one embodiment. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application belongs. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0020] It should be noted that when an element is considered to be "connected" to another element, it may be directly connected to the other element or connected to the other element through an intermediate element. For "connection" in the following embodiments, if there is an electrical signal or data transmission between the connected circuits, modules, units, etc., it should be understood as "electrically connected", "communicatively connected", etc.

[0021] As used herein, the singular forms "a", "an" and "the" may also include the plural forms unless the context clearly dictates otherwise. It should also be understood that the terms "comprises / include" or "has" etc. specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. At the same time, the terms used in this specification include any and all combinations of the related listed items.

[0022] In one embodiment, a switching tube protection circuit is provided. The switching tube can be a MOS tube or a triode, and can also be other high-power semiconductor switching devices. As Figure 1 shown, the switching tube protection circuit includes an integration loop 110, a control switch Q1, a zener diode D3, and a diode D4. The integration loop 110 is connected to the control signal input terminal, the cathode of the zener diode D3, and the anode of the diode D4. The anode of the zener diode D3 is connected to the control terminal of the control switch Q1, and the cathode of the diode D4 is connected to the first end of the switching tube Q2; the first end of the control switch Q1 is connected to the control terminal of the switching tube Q2, and the second end of the control switch Q1 is grounded; the integration loop 110 is used to pull down the potential of the control terminal of the control switch Q1 and raise the potential of the control terminal of the control switch Q1 when the switching tube Q2 is overcurrent, so that the control switch Q1 is turned on.

[0023] Among them, the types of the control switch Q1 and the switching transistor Q2 are not unique. For example, the control switch Q1 can be a triode, and the switching transistor Q2 can be a MOS transistor. In this embodiment, the control switch Q1 is an NPN-type triode, with the base as the control terminal, the collector as the first terminal, and the emitter as the second terminal. Further, the switching transistor Q2 is an N-channel MOS transistor, with the gate as the control terminal, the drain as the first terminal, and the source as the second terminal. The type of the diode D4 is not unique either. In this embodiment, the diode D4 is a Schottky high-voltage ultra-fast recovery diode. During normal operation, the integration circuit 110 pulls down the potential of the control terminal of the control switch Q1 instantaneously before the switching transistor Q2 is turned on, preventing the mis-turn-on of the control switch Q1. When an overcurrent occurs in the switching transistor Q2, after a short integration delay through the integration circuit 110, the potential of the control terminal of the control switch Q1 is raised, causing the control switch Q1 to conduct, thereby turning off the switching transistor Q2 and achieving the purpose of overcurrent protection.

[0024] It can be understood that the specific structure of the integration circuit 110 is not unique. In one embodiment, the integration circuit 110 includes a resistor R1 and a capacitor C1. The resistor R1 and the capacitor C1 are connected in series, and the common terminal is connected to the cathode of the voltage regulator diode D3 and the anode of the diode D4. The other end of the resistor R1 is connected to the control signal input terminal, and the other end of the capacitor C1 is grounded. Specifically, as Figure 1 shown, the resistor R1 and the capacitor C1 are connected in series and connected to both ends of the control signal input to receive the control signal Ui. Taking the control switch Q1 as a triode and the switching transistor Q2 as a MOS transistor as an example, during normal operation of the circuit, within the initial short period of the forward drive pulse, due to the existence of the resistor R1 and the capacitor C1, the voltage at point A is clamped at a lower potential, the voltage regulator diode D3 is turned off, and the triode is in the cut-off state. The input control signal Ui is almost entirely applied to the MOS transistor, and the input capacitor C1 is quickly charged. As the gate-source voltage Ugs of the MOS transistor increases, the MOS transistor turns on, and the drain-source voltage decreases. The diode D4 is forward-biased and conducts, the voltage at point A is clamped, and the voltage regulator diode D3 and the triode continue to be reliably turned off due to reverse bias.

[0025] When an overcurrent occurs in the MOS transistor, the drain voltage Uds rises rapidly, the diode D4 is reverse-biased and turned off, and the voltage at point A starts to rise. When it rises above the sum of the threshold voltages Uth of the voltage regulator diode D3 and the triode, the MOS transistor conducts, and the gate potential is pulled down to nearly 0V, thereby reliably turning off the MOS transistor and cutting off the circuit current. When an overcurrent is detected, the circuit can be protected within 0.1 us.

[0026] In the above switching transistor protection circuit, when the switching transistor Q2 operates normally, the integration circuit 110 pulls down the potential of the control terminal of the control switch Q1 to prevent the mis-turn-on of the control switch Q1. When an overcurrent occurs in the switching transistor Q2, the integration circuit 110 raises the potential of the control terminal of the control switch Q1 to turn on the control switch Q1, thereby turning off the switching transistor Q2, achieving the purpose of overcurrent protection. Compared with the traditional switching transistor protection method, it is not restricted by the chip to affect the response speed, improves the protection timeliness, and reduces the risk of burning the subsequent-stage chip or circuit.

[0027] In one embodiment, the switching transistor protection circuit further includes a diode D1. The diode D1 is connected in parallel with the resistor R1, and the anode of the diode D1 is connected to the common terminal of the resistor R1 and the capacitor C1. The function of the diode D1 is to discharge, preparing for the integration delay before the next turn-on.

[0028] In one embodiment, the switching transistor protection circuit further includes a diode D2. The common terminal of the resistor R1 and the capacitor C1 is connected to a zener diode D3 through the diode D2, and the cathode of the diode D2 is connected to the cathode of the zener diode D3. The specific type of the diode D2 is not unique either. In this embodiment, the diode D2 is a low-voltage ultra-fast recovery Schottky diode. Further, in one embodiment, the switching transistor protection circuit further includes a resistor R2. One end of the resistor R2 is connected to the control signal input terminal, and the other end of the resistor R2 is connected to the control terminal of the switching transistor Q2.

[0029] In addition, in one embodiment, the switching transistor protection circuit further includes a resistor R3. One end of the resistor R3 is connected to the control terminal of the control switch Q1, and the other end of the resistor R3 is grounded. Also taking the switching transistor Q2 as a MOS transistor as an example, the resistor R3 is used to suppress the high-frequency oscillation of the MOS transistor gate, thereby protecting the MOS transistor.

[0030] In one embodiment, the switching transistor protection circuit further includes a display circuit D connected to the first end of the switching transistor Q2. The display circuit D is used for real-time detection and monitoring of the circuit. Specifically, relevant parameters such as voltage and current can be displayed through the display circuit D. The display circuit D may include a parameter acquisition unit and a display unit, and may further include a storage unit. Among them, the parameter acquisition unit is connected to the first end of the switching transistor Q2, the display unit, and the storage unit, and the storage unit is used for parameter storage. Further, in one embodiment, the switching transistor protection circuit further includes an alarm circuit B connected to the first end of the control switch Q1. When an overcurrent occurs in the circuit, the alarm circuit B issues an alarm signal in a timely manner.

[0031] In one embodiment, the switch tube protection circuit may further include a display circuit D and an alarm circuit B. When an abnormal circuit enters the protection state, the alarm circuit B gives an alarm indication, and at the same time, the display circuit D displays the current on the MOS tube at this time to monitor the circuit state in real time. When the circuit is operating normally, the alarm circuit is not triggered, and the display circuit D displays the operating current and voltage parameters. During operation, the circuit gives an alarm once and the display circuit D stores once, thereby further ensuring the safety and reliability of the circuit.

[0032] In one embodiment, a circuit device is further provided, which includes a switch tube and the above-mentioned switch tube protection circuit. Among them, the circuit device can be applied to a control circuit and a switching power supply circuit. The switch tube can be a MOS tube or a triode, and can also be other high-power semiconductor switching devices.

[0033] Specifically, as Figure 1 shown, the switch tube protection circuit includes an integration loop 110, a control switch Q1, a zener diode D3, and a diode D4. The integration loop 110 is connected to the control signal input terminal, the cathode of the zener diode D3, and the anode of the diode D4. The anode of the zener diode D3 is connected to the control terminal of the control switch Q1, and the cathode of the diode D4 is connected to the first end of the switch tube Q2. The first end of the control switch Q1 is connected to the control terminal of the switch tube Q2, and the second end of the control switch Q1 is grounded. The integration loop 110 is used to pull down the potential of the control terminal of the control switch Q1 and raise the potential of the control terminal of the control switch Q1 when the switch tube Q2 is overcurrent, so that the control switch Q1 is turned on.

[0034] The types of the control switch Q1 and the switch tube Q2 are not unique. For example, the control switch Q1 can be a triode, and the switch tube Q2 can be a MOS tube. In this embodiment, the control switch Q1 is an NPN-type triode, with the base as the control terminal, the collector as the first end, and the emitter as the second end. Further, the switch tube Q2 is an N-channel MOS tube, with the gate as the control terminal, the drain as the first end, and the source as the second end. The type of the diode D4 is not unique either. In this embodiment, the diode D4 is a Schottky high-voltage ultra-fast recovery diode. During normal operation, the integration loop 110 pulls down the potential of the control terminal of the control switch Q1 at the moment before the switch tube Q2 is turned on to prevent the mis-turn-on of the control switch Q1. When the switch tube Q2 is overcurrent, after a short integration delay through the integration loop 110, the potential of the control terminal of the control switch Q1 is raised, so that the control switch Q1 is turned on, thereby turning off the switch tube Q2 to achieve the purpose of overcurrent protection.

[0035] In one embodiment, the integration loop 110 includes a resistor R1 and a capacitor C1. The resistor R1 and the capacitor C1 are connected in series, and the common terminal is connected to the cathode of the zener diode D3 and the anode of the diode D4. The other end of the resistor R1 is connected to the control signal input terminal, and the other end of the capacitor C1 is grounded. Specifically, asFigure 1 As shown, resistor R1 and capacitor C1 are connected in series across both ends of the control signal input to receive the control signal Ui. Taking the control switch Q1 as a triode and the switching transistor Q2 as a MOS transistor as an example, when the circuit is operating normally, within the initial short period of the forward drive pulse, due to the existence of resistor R1 and capacitor C1, the voltage at point A is clamped at a relatively low potential, the zener diode D3 is cut off, and the triode is in the cut-off state. The input control signal Ui is almost entirely applied to the MOS transistor, and the input capacitor C1 is quickly charged. As the gate-source voltage Ugs of the MOS transistor increases, the MOS transistor turns on, and the drain-source voltage decreases. The diode D4 is forward-biased and conducts, clamping the voltage at point A, and the zener diode D3 and the triode continue to be reliably cut off due to reverse bias.

[0036] When an overcurrent occurs in the MOS transistor, the drain voltage Uds rises rapidly, the diode D4 is reverse-biased and cut off, and the voltage at point A starts to rise. When it rises above the sum of the threshold voltage Uth of the zener diode D3 and the triode, the MOS transistor conducts, and the gate potential is pulled down to nearly 0V, thereby reliably turning off the MOS transistor, cutting off the circuit current, and protecting the circuit within 0.1 us when an overcurrent is detected.

[0037] In one embodiment, the switching transistor protection circuit further includes a diode D1. The diode D1 is connected in parallel with the resistor R1, and the anode of the diode D1 is connected to the common terminal of the resistor R1 and the capacitor C1. The function of the diode D1 is to discharge and prepare for the integration delay before the next turn-on.

[0038] In one embodiment, the switching transistor protection circuit further includes a diode D2. The common terminal of the resistor R1 and the capacitor C1 is connected to the zener diode D3 through the diode D2, and the cathode of the diode D2 is connected to the cathode of the zener diode D3. In this embodiment, the diode D2 is a low-voltage ultra-fast recovery Schottky diode. Further, in one embodiment, the switching transistor protection circuit further includes a resistor R2. One end of the resistor R2 is connected to the control signal input terminal, and the other end of the resistor R2 is connected to the control terminal of the switching transistor Q2.

[0039] In one embodiment, the switching transistor protection circuit further includes a resistor R3. One end of the resistor R3 is connected to the control terminal of the control switch Q1, and the other end of the resistor R3 is grounded. Also taking the switching transistor Q2 as a MOS transistor as an example, the resistor R3 is used to suppress the high-frequency oscillation of the MOS transistor gate, thereby protecting the MOS transistor.

[0040] In one embodiment, the switch tube protection circuit further includes a display circuit D connected to the first end of the switch tube Q2. The display circuit D is used for real-time detection and monitoring of the circuit. Specifically, relevant parameters such as voltage and current can be displayed through the display circuit D. Further, in one embodiment, the switch tube protection circuit further includes an alarm circuit B connected to the first end of the control switch Q1. When an overcurrent occurs in the circuit, the alarm circuit B issues an alarm signal in a timely manner.

[0041] In one embodiment, the switch tube protection circuit may also include a display circuit D and an alarm circuit B at the same time. When an abnormal circuit enters the protection state, the alarm circuit B gives an alarm indication, and at the same time the display circuit D displays the current on the MOS tube at this time to monitor the circuit state in real time; when the circuit is operating normally, the alarm circuit is not triggered, and the display circuit D displays the operating current and voltage parameters. During operation, the circuit gives an alarm once and the display circuit D stores once, thereby further ensuring the safety and reliability of the circuit.

[0042] To better understand the above-mentioned switch tube protection circuit and drive circuit, the following will be explained in detail with specific embodiments.

[0043] With the rapid development of power electronics, for high-power semiconductor devices acting on switching devices, the requirement for their switching speed is getting faster and faster, and the application range is more extensive. This application designs a drive and protection circuit suitable for high-power and high-reliability MOSFET tubes, giving full play to the advantages of MOSFET tubes, realizing high-power circuit drive, having high-speed drive coupling and fault response speed, improving the detection of overcurrent faults and quickly making protection actions, having strong anti-interference ability, simple structure, easy adjustment of parameters, and low cost.

[0044] Specifically, this application provides a high-power drive and current display protection circuit, which is composed of a MOS tube, a triode, an ultra-fast recovery diode, an integration circuit and an alarm display circuit. Selecting a MOSFET tube can meet the requirements of a high-power drive circuit; selecting a triode can provide overcurrent protection for the MOS tube, increasing the reliability and safety of the circuit; selecting an integration circuit and an ultra-fast recovery diode can quickly realize overcurrent detection and protection. Design an alarm and display module circuit according to the circuit characteristics for real-time monitoring and recording and storing data. This circuit realizes the drive requirements for high-power circuits, quickly detects overcurrent signals, improves the detection and protection efficiency, and reduces the risk of false triggering or delayed detection. The circuit has high reliability and low cost.

[0045] Such as Figure 1As shown in the figure, diode D1 and capacitor C1 in the circuit are connected in series and are connected to both ends of the input of the control signal. The cathode of diode D1 and the upper end of resistor R1 are joined to the left end of resistor R2. The right end of resistor R2 and the collector of triode Q1 are connected to the gate G of the MOS transistor together. The lower end of resistor R1 is connected to the anode of Schottky diode D4 and the anode of diode D2. The cathode of diode D2 is connected to the cathode of zener diode D3. The anode of zener diode D3 and the upper end of resistor R3 are connected to the base of triode Q1. Resistor R3, capacitor C1 and the emitter of triode Q1 are grounded together. The cathode of Schottky diode D4 is connected to the drain of the MOS transistor. An alarm circuit B is set at triode Q1. When an abnormal circuit enters the protection state, the alarm circuit B gives an alarm indication. At the same time, the display circuit D shows the current on the MOS transistor at this time to monitor the circuit state in real time. When the circuit is operating normally, the alarm circuit B is not triggered. The display circuit D shows the operating current and voltage parameters. During operation, the circuit gives an alarm once and the display circuit D stores once, thus further ensuring the safety and reliability of the circuit.

[0046] When the circuit is working normally, within the initial short period of the forward drive pulse, due to the existence of resistor R1 and capacitor C1, the voltage at point A is clamped at a lower potential, zener diode D3 is cut off, and triode Q1 is in the cut-off state. The input control signal Ui is almost entirely applied to MOS transistor Q2 and rapidly charges the input capacitor C1. As the gate-source voltage Ugs of MOS transistor Q2 increases, MOS transistor Q2 turns on and the drain-source voltage decreases. Schottky diode D4 is forward-biased and conducts, the voltage at point A is clamped, and zener diode D3 and triode Q1 continue to be reliably cut off due to reverse bias. The function of diode D1 in the figure is to discharge, preparing for the integration delay before the next turn-on; resistor R3 is used to suppress high-frequency oscillations at the gate and protect the MOSFET transistor.

[0047] Figure 2 The figure shows the drive waveform diagram when the circuit is working normally. Figure 3 The figure shows the drive waveform diagram when the circuit has overcurrent protection. When the MOSFET transistor has an overcurrent, the drain voltage Uds rises rapidly, Schottky diode D4 is reverse-biased and cut off, and the voltage at point A begins to rise. When it rises above the sum of the threshold voltages Uth of zener diode D3 and triode Q1, MOS transistor Q2 conducts, and the gate potential is pulled down to nearly 0V, thus reliably turning off MOS transistor Q2, cutting off the circuit current, detecting the overcurrent, and protecting the circuit within 0.1 us, as Figure 3 shown in the figure.

[0048] The integration circuit composed of resistor R1 and capacitor C1 mainly has the following functions: During normal operation, it pulls down the potential at point A instantaneously before the MOSFET is turned on, preventing the accidental turn-on of transistor Q1. During overcurrent, through a short integration delay, it raises the potential at point A to the turn-on voltage of transistor Q1, causing transistor Q1 to conduct, and clamping the gate voltage at point G. MOS transistor Q2 is turned off, thus achieving the purpose of overcurrent protection.

[0049] The designed display circuit D and alarm circuit B are used to detect and monitor the circuit in real time. When the circuit is operating normally, the display circuit shows relevant parameters such as voltage and current. When overcurrent occurs in the circuit, the alarm circuit B issues an alarm signal in a timely manner, and the display circuit D shows the current and voltage data of the MOS transistor during overcurrent, records the number of times of protection during the entire test cycle, and further confirms the rationality and reliability of the circuit design.

[0050] Figure 1 In the circuit, diode D4 is a Schottky high-voltage ultra-fast recovery diode, and diode D2 is a low-voltage ultra-fast recovery Schottky diode, which can eliminate the influence of the large junction capacitance of zener diode D3 forming a charge displacement current on transistor Q1.

[0051] For the above-mentioned high-power drive and current display protection circuit, a MOSFET is selected as the core device to build the drive circuit, which can meet the high-power requirements of the circuit. At the same time, a combination of a transistor, a MOSFET, and an ultra-fast recovery diode in the charge and discharge circuit is used to achieve high-speed overcurrent protection, with timely protection response and high reliability. And through the external display and alarm circuit, relevant parameters are displayed for real-time monitoring.

[0052] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as within the scope described in this specification.

[0053] The above-described embodiments merely represent several implementation manners of the present application, and their descriptions are relatively specific and detailed, but should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims.

Claims

1. A switching tube protection circuit, characterized in that, It includes an integrating circuit, a control switch, a voltage stabilizing diode D3, and a diode D4. The integrating circuit is connected to the control signal input terminal, the cathode of the voltage stabilizing diode D3, and the anode of the diode D4. The anode of the voltage stabilizing diode D3 is connected to the control terminal of the control switch, and the cathode of the diode D4 is connected to the first end of the switching transistor. The first end of the control switch is respectively connected to the control terminal of the switching transistor and the control signal input terminal. The second end of the control switch is grounded and is connected to the second end of the switching transistor. The integrating circuit is used to pull down the potential of the control terminal of the control switch and raise the potential of the control terminal of the control switch when the switching transistor is overcurrent, so that the control switch is turned on. Among them, the integrating circuit includes a resistor R1 and a capacitor C1. The resistor R1 and the capacitor C1 are connected in series, and the common terminal is connected to the cathode of the voltage stabilizing diode D3 and the anode of the diode D4. The non-common terminal of the resistor R1 is connected to the control signal input terminal, and the non-common terminal of the capacitor C1 is grounded. Among them, when the switching transistor protection circuit is working normally, due to the existence of the resistor R1 and the capacitor C1, the voltage of the common terminal is clamped, the voltage stabilizing diode D3 is cut off, the control switch is in the cut-off state, the control signal input from the control signal input terminal is applied to the control terminal of the switching transistor, and the capacitor C1 is charged. As the gate-source voltage of the switching transistor increases, the switching transistor is turned on, the source-drain voltage of the switching transistor decreases, the diode D4 is forward-biased and turned on, the common terminal is clamped, and the voltage stabilizing diode D3 and the control switch continue to be cut off due to reverse bias. When the switching transistor is overcurrent, the drain voltage of the switching transistor rises, the diode D4 is reverse-biased and cut off, and the potential of the common terminal begins to rise. When the potential of the common terminal is higher than the sum of the threshold voltages of the voltage stabilizing diode D3 and the control switch, the control switch is turned on, the gate potential of the switching transistor is pulled down to nearly 0V, and the switching transistor is turned off.

2. The switching tube protection circuit according to claim 1, wherein It also includes a diode D1. The diode D1 is connected in parallel with the resistor R1, and the anode of the diode D1 is connected to the common terminal of the resistor R1 and the capacitor C1.

3. The switching tube protection circuit according to claim 1, characterized in that, It also includes a diode D2. The common terminal of the resistor R1 and the capacitor C1 is connected to the voltage stabilizing diode D3 through the diode D2, and the cathode of the diode D2 is connected to the cathode of the voltage stabilizing diode D3.

4. The switching tube protection circuit according to claim 1, characterized in that It also includes a resistor R2. One end of the resistor R2 is connected to the control signal input terminal, and the other end of the resistor R2 is connected to the control terminal of the switching transistor.

5. The switch tube protection circuit according to claim 1, wherein, It also includes a resistor R3. One end of the resistor R3 is connected to the control terminal of the control switch, and the other end of the resistor R3 is grounded.

6. The switching tube protection circuit according to any one of claims 1-5, characterized in that, It also includes a display circuit connected to the first end of the switching transistor.

7. The switching tube protection circuit according to any one of claims 1-5, characterized in that, It also includes an alarm circuit connected to the first end of the control switch.

8. The switching tube protection circuit according to any one of claims 1-5, characterized in that, The switching transistor is a MOS transistor, and the control switch is a triode.

9. The switching tube protection circuit according to claim 1, wherein The diode D4 is a Schottky high-voltage ultra-fast recovery diode.

10. A driving circuit, characterized in that, It includes a switching transistor and the switching transistor protection circuit according to any one of claims 1-9.

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