Overcurrent protection circuit and electrical equipment

Abstract

The present invention discloses an overcurrent protection circuit and electrical equipment. The circuit includes: a detection module, a first end of which is connected between the second end of the first resistor and the anode of the first unidirectional element, and a second end of which is grounded, for detecting whether an overcurrent fault occurs in a power switch device, and outputting a control voltage after an overcurrent fault occurs in the power switch device; wherein the first end of the first resistor is connected to the desaturation detection pin of the driving chip, and the cathode of the first unidirectional element is connected to the drain of the power switch device; a protection module, a first end of which is connected to the third end of the detection module, a second end of which is connected between the gate of the power switch device and the first resistor, and a third end of which is grounded, for conducting under the control of the control voltage to reduce the current passing through the power switch device. Through the present invention, it is possible to avoid damage to the power switch device caused by an overcurrent fault and improve the reliability of the power switch device.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic circuits, and in particular to an overcurrent protection circuit and electrical equipment. Background Art

[0002] Power switching devices (such as a composite IGBT switch consisting of a bipolar transistor and an insulated gate field effect transistor) are increasingly being used in motor drives, inverters and other fields due to their low driving power and low saturation voltage.

[0003] As the frequency of use of power switching devices increases, power switching device damage problems occur frequently, and their driving and protection are receiving more and more attention. Infineon, Toshiba and other manufacturers have successively developed power switching device driving optocouplers to drive and protect power switching devices. However, since it takes a certain amount of time for the driving optocoupler protection circuit to control the power switching device to shut down, the current flowing through the power switching device is still large before it is completely shut down, that is, the protection circuit in the existing driving optocoupler cannot protect the power switching device in time, causing the problem of power switching device damage to occur from time to time.

[0004] With respect to the problem that the protection circuit in the prior art cannot protect the power switch device in time, no effective solution has been proposed yet. Summary of the invention

[0005] An overcurrent protection circuit and an electrical device are provided in the embodiments of the present invention to solve the problem that the protection circuit in the prior art cannot protect the power switch device in time.

[0006] In order to solve the above technical problems, the present invention provides an overcurrent protection circuit, which is applied to a power switch device, wherein the power switch device is connected to a driver chip, and the circuit comprises:

[0007] A detection module, a first end of which is connected between the second end of the first resistor and the anode of the first unidirectional element, and a second end of which is grounded, for detecting whether an overcurrent fault occurs in the power switch device, and outputting a control voltage after an overcurrent fault occurs in the power switch device; wherein the first end of the first resistor is connected to the desaturation detection pin of the driving chip, and the cathode of the first unidirectional element is connected to the drain of the power switch device;

[0008] A protection module, a first end of which is connected to the third end of the detection module, and a second end of which is connected between the gate of the power switch device and the driving resistor, is used to be turned on under the control of the control voltage to reduce the current passing through the power switch device.

[0009] Furthermore, the detection module includes:

[0010] A second resistor and a third resistor are arranged in series, wherein a first end of a series branch formed by the second resistor and the third resistor being connected in series is connected between the second end of the first resistor and the anode of the first unidirectional element, and a second end is grounded;

[0011] The line between the second resistor and the third resistor is connected to the first end of the protection module.

[0012] Furthermore, the protection module includes:

[0013] A first switch, whose base is connected to the third terminal of the detection module and whose emitter is grounded, is used to be turned on when an overcurrent fault occurs in the power switch device and turned off when the power switch device is normally turned on;

[0014] A voltage stabilizing unit, a first end of which is connected to the collector of the first switch, and a second end of which is connected between the gate of the power switching device and the driving resistor, wherein the voltage stabilizing unit is used to be cut off when the first switch is turned off, and to be turned on when the first switch is turned on, so as to reduce the current passing through the power switching device.

[0015] Furthermore, the protection module also includes:

[0016] The second unidirectional element has an anode connected between the gate of the power switch device and the driving resistor, and a cathode connected to the first end of the voltage stabilizing unit.

[0017] Furthermore, the protection module also includes:

[0018] A fourth resistor, a first end of which is connected between the anode of the second unidirectional element and the driving resistor, and a second end of which is grounded, is used to reduce the driving resistance value when the power switch device is turned off.

[0019] Furthermore, the protection circuit further includes:

[0020] A first capacitor, a first end of which is connected between the anode of the second unidirectional element and the gate of the power switch device, is used to reduce the conduction speed of the power switch device.

[0021] Furthermore, the circuit further comprises:

[0022] A second capacitor, a first end of which is connected between the desaturation detection pin and the first resistor and a second end of which is grounded, is used to control the voltage of the desaturation detection pin, thereby controlling whether the desaturation detection pin triggers overcurrent protection.

[0023] Furthermore, the circuit further comprises:

[0024] A third capacitor, a first end of which is connected to the ground pin of the driver chip, and a second end of which is connected between the positive voltage pin of the driver chip and the positive voltage power supply, and the third capacitor is used to filter the voltage provided by the positive voltage power supply;

[0025] a fourth capacitor, a first end of which is connected between the positive voltage pin of the driver chip and the positive voltage power supply, and a second end of which is connected between the negative voltage pin of the driver chip and the negative voltage power supply, and the fourth capacitor is used to filter the voltage provided by the positive voltage power supply and the voltage provided by the negative voltage power supply;

[0026] A fifth capacitor has a first end connected to the ground and a second end connected between the negative voltage pin of the driving chip and the negative voltage power supply. The fifth capacitor is used to filter the voltage provided by the negative voltage power supply.

[0027] The present invention further provides an electrical device, comprising a power switch device and a drive chip, characterized in that the electrical device also comprises the above-mentioned overcurrent protection circuit.

[0028] Furthermore, the electrical equipment includes at least one of the following:

[0029] Air conditioners, washing machines, refrigerators, water heaters, fans, dryers, air purifiers, water purifiers, and water purifiers.

[0030] By applying the technical solution of the present invention, a detection module is used to detect whether an overcurrent fault occurs in a power switch device, and a control voltage is output after an overcurrent fault occurs in the power switch device; the protection module is turned on under the control of the control voltage to reduce the current passing through the power switch device. After the desaturation detection pin triggers the overcurrent protection, before the power switch device is completely shut down, the current of the power switch device can be reduced, thereby avoiding damage to the power switch device caused by an overcurrent fault and improving the reliability of the power switch device. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a structural diagram of an overcurrent protection circuit according to an embodiment of the present invention;

[0032] Figure 2 FIG. 4 is a structural diagram of an overcurrent protection circuit according to another embodiment of the present invention. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings, and "multiple" generally includes at least two.

[0035] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0036] It should be understood that although the terms first, second, third, etc. may be used to describe resistors in embodiments of the present invention, these resistors should not be limited to these terms. These terms are only used to distinguish resistors arranged at different positions. For example, without departing from the scope of embodiments of the present invention, a first resistor may also be referred to as a second resistor, and similarly, a second resistor may also be referred to as a first resistor.

[0037] As used herein, the words "if" and "if" may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0038] It should also be noted that the term "includes", "comprising" or any other variation thereof is intended to cover non-exclusive inclusion, so that a commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprising a ..." do not exclude the existence of other identical elements in the commodity or device including the elements.

[0039] The optional embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0040] Example 1

[0041] This embodiment provides an overcurrent protection circuit, which is applied to a power switch device, wherein the power switch device is connected to a driver chip. Figure 1 is a structural diagram of an overcurrent protection circuit according to an embodiment of the present invention, such as Figure 1As shown, the driving chip U of the power switching device (IGBT is taken as an example in this embodiment) includes a ground pin VE, a positive voltage pin VCC, a negative voltage pin VEE, and an output pin VOUT, wherein the ground pin VE is grounded, the positive voltage pin VCC is connected to the positive voltage power supply VCC1, the negative voltage pin VEE is connected to the negative voltage power supply VCC2, and the output pin VOUT is connected to the gate G of the IGBT through the driving resistor Rg. The driving chip U also includes a desaturation detection pin DESAT, and the desaturation detection pin DESAT is connected to the drain D of the IGBT through the first resistor R1 and the first unidirectional element D1, wherein the first unidirectional element D1 can be a diode.

[0042] In order to reduce the current of the power switch device after the desaturation detection pin triggers the overcurrent protection and before the power switch device is completely turned off, the overcurrent protection circuit includes:

[0043] Detection module 1, the first end of the detection module 1 is connected between the second end of the first resistor R1 and the anode of the first unidirectional element D1, and the second end is grounded. Since a high voltage will be generated between the second end of the first resistor R1 and the anode of the first unidirectional element D1 when an overcurrent fault occurs in the IGBT, when the desaturation detection pin DESAT detects the high voltage, the pulse output of the driver chip U will be turned off, thereby turning off the IGBT. However, it takes a certain amount of time for the IGBT to be completely turned off. Before the IGBT is completely turned off, the current in the IGBT is still relatively large. Therefore, the detection module 1 detects whether an overcurrent fault occurs in the IGBT by detecting the voltage between the first resistor R1 and the first unidirectional element D1, and outputs a control voltage to the protection module 2 after an overcurrent fault occurs in the IGBT.

[0044] The protection module 2 has a first end connected to the third end of the detection module 1, a second end connected between the gate G of the IGBT and the driving power supply Rg, and a third end connected to ground, and is used to reduce the current passing through the IGBT under the control of the above-mentioned control voltage.

[0045] The overcurrent protection circuit of this embodiment detects whether an overcurrent fault occurs in the power switch device through a detection module, and outputs a control voltage after the overcurrent fault occurs in the power switch device; the protection module is turned on under the control of the control voltage to reduce the current passing through the power switch device. After the desaturation detection pin triggers the overcurrent protection, before the power switch device is completely shut down, the current of the power switch device can be reduced to avoid damage to the power switch device caused by the overcurrent fault, thereby improving the reliability of the power switch device.

[0046] Example 2

[0047] This embodiment provides another overcurrent protection circuit. Figure 2FIG. 1 is a structural diagram of an overcurrent protection circuit according to another embodiment of the present invention. In order to realize the conversion of the voltage between the second end of the first resistor R1 and the anode of the first unidirectional element D1 into a control voltage for controlling the protection module 2 to be turned on, as shown in FIG. Figure 2 As shown, the detection module 1 includes:

[0048] A second resistor R2 and a third resistor R3 are arranged in series, and one end of the series branch formed by the second resistor R2 and the third resistor R3 is connected to between the second end of the above-mentioned first resistor R1 and the anode of the first unidirectional element D1, and the other end is grounded; specifically, the first end of the second resistor R2 is connected to between the second end of the above-mentioned first resistor R1 and the anode of the first unidirectional element D1, and the second end of the second resistor R2 is connected to the first end of the third resistor R3; the second end of the third resistor R3 is grounded; the line between the second resistor R2 and the third resistor R3 is connected to the first end of the protection module, and the voltage between the second end of the first resistor R1 and the anode of the first unidirectional element D1 is divided by the second resistor R2 and the third resistor R3, and the line lead-out end between the second resistor R2 and the third resistor R3 serves as the third end of the detection module 1 to output the divided voltage.

[0049] In order to achieve conduction when input control voltage is applied, such as Figure 2 As shown, the protection module 2 includes: a first switch Q1, the base of the first switch Q1 is connected to the third end of the detection module 1, the emitter is grounded, and the first switch Q1 is turned on when an overcurrent fault occurs in the IGBT, and is turned off when the IGBT is normally turned on. When an overcurrent fault occurs in the IGBT, the desaturation detection pin DESAT detects a higher voltage, and the pulse output of the driver chip U will be turned off, thereby turning off the IGBT. However, before the IGBT is completely turned off, the current in the IGBT is still relatively large; at this time, the voltage U2 at the detection point a between the second end of the first resistor R1 and the anode of the first unidirectional element D1 is relatively high, and the voltage U3 output at the detection point b between the second resistor R2 and the third resistor R3 is also relatively high, driving the first switch Q1 to turn on, thereby turning on the protection module 2; wherein, U3 = (Vds + VD1)*

[0050] The resistance value of the third resistor R3 / (the resistance value of the second resistor R2+the resistance value of the third resistor R3), Vds is the voltage between the drain D and the source S of the IGBT, and VD1 is the voltage across the first unidirectional element D1; when the IGBT is normally turned on, the voltage detected by the desaturation detection pin DESAT is relatively low. Assuming that the output current of the desaturation detection pin DESAT is I1, the voltage detected by the desaturation detection pin DESAT is U1=Vds+VD1+I1×the resistance value of the first resistor R1, and Vds is the voltage between the drain D and the source S of the IGBT. At this time, the voltage U2 at the detection point a between the second end of the first resistor R1 and the anode of the first unidirectional element D1 is relatively low, and the voltage U3 outputted at the detection point b between the second resistor R2 and the third resistor R3 is also relatively low. At this time, the voltage U3 is not enough to drive the first switch Q1 to turn on, so the first switch Q1 is turned off, and then the protection module 2 is turned off. In this embodiment, the first switch Q1 is an NPN transistor.

[0051] The protection module 2 also includes a voltage stabilizing unit Z1, a first end of the voltage stabilizing unit Z1 is connected to the collector of the first switch Q1, and a second end is connected between the gate G of the IGBT and the driving resistor Rg. The voltage stabilizing unit Z1 is cut off when the first switch Q1 is turned off, and is turned on when the first switch Q1 is turned on, that is, the voltage stabilizing unit Z1 is turned on after an overcurrent fault occurs in the IGBT to clamp the voltage of the gate G of the IGBT to a lower voltage, thereby reducing the current passing through the IGBT.

[0052] In order to prevent reverse current from flowing through the voltage stabilizing unit Z1 and the first switch Q1, the protection module further includes: a second unidirectional element D2, the anode of the second unidirectional element D2 is connected between the gate G of the IGBT and the driving resistor Rg, and the cathode is connected to the first end of the voltage stabilizing unit Z1. Through the second unidirectional element D2, the control current can only flow from the gate G of the IGBT to the collector and emitter of the voltage stabilizing unit Z1 and the first switch Q1. In this embodiment, the second unidirectional element D2 is a diode, and the voltage stabilizing unit Z1 is a voltage stabilizing diode.

[0053] When controlling the IGBT to turn off, ideally, once the shutdown signal is issued, the IGBT will turn off immediately. However, in actual applications, there is always a certain delay in the shutdown of the IGBT. In order to improve the shutdown response speed of the IGBT, Figure 2 As shown, the protection module 2 further includes:

[0054] The fourth resistor R4, the first end of the fourth resistor R4 is connected between the anode of the second unidirectional element D2 and the driving resistor Rg, and the second end is grounded. When the IGBT inputs a shutdown signal, the fourth resistor R4 and the driving resistor Rg are in parallel. After the fourth resistor R4 and the driving resistor Rg are connected in parallel, the total driving resistance value is reduced, thereby improving the IGBT shutdown response speed.

[0055] In the above embodiments, since people hope that the IGBT can be turned off quickly when the turn-off signal is input, the fourth resistor R4 is used to improve the turn-off response. However, when the IGBT is input with a turn-on signal, if the response is too fast, the IGBT will be subjected to too large an instantaneous impact. Therefore, in order to reduce the turn-on speed of the IGBT, as shown in FIG. Figure 2 As shown, the protection circuit further includes:

[0056] The first capacitor C1 has a first end connected between the anode of the second unidirectional element D2 and the gate G of the IGBT, and is used to reduce the conduction speed of the IGBT to prevent the IGBT from being subjected to excessive instantaneous impact.

[0057] When the IGBT is turned on normally, there is no need to trigger the overcurrent protection. The voltage detected by the desaturation detection pin DESAT should be maintained at a low value. When an overcurrent fault occurs in the IGBT, the voltage detected by the desaturation detection pin DESAT should increase. In order to control the voltage detected by the desaturation detection pin DESAT, such as Figure 2 As shown, the above circuit also includes:

[0058] The second capacitor C2, the first end of the second capacitor C2 is connected between the desaturation detection pin DESAT and the first resistor R1, the second end of the second capacitor C2 is grounded, and the second capacitor C2 is used for when the IGBT is normally turned on, the two ends of the second capacitor C2 are charged to a certain value and then no longer charged, so that the desaturation detection pin DESAT always detects a lower voltage, and when an overcurrent fault occurs in the IGBT, the second capacitor C2 continues to charge, so that the desaturation detection pin DESAT detects a higher voltage, triggering the overcurrent protection.

[0059] According to the above, the ground pin VE of the driver chip U is grounded, the positive voltage pin VCC is connected to the positive voltage power supply VCC1, and the negative voltage pin VEE is connected to the negative voltage power supply VCC2. Since the positive voltage power supply VCC1 and the negative voltage power supply VCC2 contain interference signals, in order to remove these interference signals, the above-mentioned overcurrent protection circuit also includes:

[0060] The third capacitor C3 has a first end connected to the ground pin VE of the driver chip U, and a second end connected between the positive voltage pin VCC of the driver chip U and the positive voltage power supply VCC1. The third capacitor C3 is used to filter the voltage provided by the positive voltage power supply VCC1 to remove interference signals.

[0061] The overcurrent protection circuit also includes a fourth capacitor C4, a first end of the fourth capacitor C4 is connected between the positive voltage pin VCC of the driver chip U and the positive voltage power supply VCC1, and a second end is connected between the negative voltage pin VEE of the driver chip U and the negative voltage power supply VCC2. The fourth capacitor C4 is used to filter the voltage provided by the positive voltage power supply VCC1 and the voltage provided by the negative voltage power supply VCC2 to remove interference signals.

[0062] The overcurrent protection circuit also includes a fifth capacitor C5, a first end of the fifth capacitor C5 is grounded, and a second end thereof is connected between the negative voltage pin VEE of the driver chip U and the negative voltage power supply VCC2. The fifth capacitor C5 is used to filter the voltage provided by the negative voltage power supply VCC2 to remove interference signals.

[0063] Example 3

[0064] This embodiment provides another overcurrent protection circuit. The overcurrent protection circuit of this embodiment is mentioned above. Figure 2 As shown in the figure, the driving chip U is specifically a driving optocoupler, which is connected to a positive voltage power supply VCC1 and a negative voltage power supply VCC2. The voltage output by the positive voltage power supply VCC1 and the negative voltage power supply VCC2 is filtered by a third capacitor C3, a fourth capacitor C4, and a fifth capacitor C5 to power the driving optocoupler.

[0065] A desaturation detection pin DESAT is set on the driving optocoupler. When an overcurrent fault occurs in the IGBT, the desaturation detection pin DESAT will output a high voltage, and the driving optocoupler will control the pulse output to turn off, thereby turning off the IGBT.

[0066] The overcurrent protection circuit driven by the IGBT includes a desaturation detection circuit, an overcurrent protection circuit and a pulse output circuit.

[0067] The desaturation detection circuit includes a second capacitor C2, a first resistor R1 and a first unidirectional element D1. When the IGBT is normally turned on, the desaturation detection pin DESAT outputs a weak current and detects a lower voltage. At this time, the voltage is lower than the trigger voltage of the desaturation detection pin DESAT, and the driver optocoupler does not report an overcurrent fault. Assuming that the output current of the desaturation detection pin DESAT is I1, the voltage value at this time is U1 = Vds + VD1 + I1 × R1. When an overcurrent fault occurs, the voltage Vds between the drain D and source S of the IGBT increases, the second capacitor C2 starts to charge, and the voltage detected by the desaturation detection pin DESAT increases. When the voltage increases to a level higher than the trigger voltage of the desaturation detection pin DESAT, the driver optocoupler reports an overcurrent fault, the output pin VOUT IGBT is turned off, and the IGBT is controlled to turn off.

[0068] The overcurrent protection circuit includes a detection module and a protection module: the detection module includes a second resistor R2 and a third resistor R3, and the protection module includes a second unidirectional element D2, a voltage stabilizing element Z1 and a first switch Q11. When an overcurrent fault occurs, the protection module can clamp the gate level of the IGBT to a low level.

[0069] The protection module includes a second unidirectional element D2, a voltage stabilizing element Z1 and a first switch Q11. When the IGBT is normally turned on, a voltage U2 is detected at point a, and a voltage U3 is detected at point b. At this time, U3 is less than the turn-on voltage of the first switch Q11, and the first switch Q11 is not turned on. U3=U3=(Vds+VD1)×resistance of the third resistor R3 / (resistance of the second resistor R2+resistance of the third resistor R3). When an overcurrent fault occurs, Vds increases, and U2 and U3 increase. When the voltage at the two points is higher than the turn-on voltage of the first switch Q11, the first switch Q11 is turned on. Before the second capacitor C2 is charged to the trigger voltage of the desaturation detection pin DESAT, the voltage stabilizing element Z1 clamps the voltage of the IGBT gate G to a low level, the amplitude of the fault current is reduced, the power loss of the IGBT is reduced, and the short-circuit withstand time of the device is extended, thereby ensuring that the IGBT will not be damaged due to overcurrent before it is turned off.

[0070] In addition, when the IGBT is subjected to short-term noise and interference spikes, the DESAT pin detects the spike voltage, the second capacitor C2 starts to charge, and the point a also detects the spike voltage. After the spike voltage is divided by the second resistor R3 and the third resistor R3, a voltage value is output through point b. The voltage value exceeds the conduction threshold of the first switch Q11, the first switch Q11 is turned on, and the voltage stabilizing element Z1 works to pull down the IGBT gate voltage and reduce the interference spike. Therefore, the second capacitor C2 will not be charged to the DESAT threshold voltage, the driving optocoupler will not report overcurrent protection, and the circuit can work normally.

[0071] Example 4

[0072] The present embodiment provides an electrical device, including a power switch device and a driver chip. The electrical device also includes the above-mentioned overcurrent protection circuit, which is used to implement overcurrent protection of the power switch device. After the desaturation detection pin triggers the overcurrent protection, before the power switch device is completely shut down, the current of the power switch device is reduced to avoid damage to the power switch device, improve the reliability of the power switch device, and thus improve the reliability of the entire electrical device. In the present embodiment, the electrical device includes at least one of the following: an air conditioner, a washing machine, a refrigerator, a water heater, a fan, a dryer, an air purifier, a water purifier, and a water purifier.

[0073] The device embodiments described above are merely illustrative, wherein the modules described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical modules, i.e., they may be located in one place or distributed on multiple network modules. Some or all of the modules may be selected according to actual needs to achieve the purpose of the present embodiment.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An overcurrent protection circuit, applied to a power switch device, wherein the power switch device is connected to a driver chip, characterized in that: The circuit comprises: A detection module, a first end of which is connected between the second end of the first resistor and the anode of the first unidirectional element, and a second end of which is grounded, for detecting whether an overcurrent fault occurs in the power switch device, and outputting a control voltage after an overcurrent fault occurs in the power switch device; wherein the first end of the first resistor is connected to the desaturation detection pin of the driving chip, and the cathode of the first unidirectional element is connected to the drain of the power switch device; a protection module, a first end of which is connected to the third end of the detection module, a second end of which is connected between the gate of the power switch device and the driving resistor, and a third end of which is grounded, and is used to be turned on under the control of the control voltage to reduce the current passing through the power switch device; The protection module includes: a first switch, whose base is connected to the third end of the detection module and whose emitter is grounded, and is used to be turned on when an overcurrent fault occurs in the power switching device, and turned off when the power switching device is normally turned on; a voltage stabilizing unit, whose first end is connected to the collector of the first switch and whose second end is connected between the gate of the power switching device and the driving resistor, and the voltage stabilizing unit is used to be cut off when the first switch is turned off, and turned on when the first switch is turned on, so as to reduce the current passing through the power switching device.

2. The circuit according to claim 1, characterized in that The detection module comprises: A second resistor and a third resistor are arranged in series, wherein a first end of a series branch formed by the second resistor and the third resistor being connected in series is connected between the second end of the first resistor and the anode of the first unidirectional element, and a second end is grounded; The line between the second resistor and the third resistor is connected to the first end of the protection module.

3. The circuit according to claim 1, characterized in that The protection module also includes: The second unidirectional element has an anode connected between the gate of the power switch device and the driving resistor, and a cathode connected to the first end of the voltage stabilizing unit.

4. The circuit according to claim 3, characterized in that The protection module also includes: A fourth resistor, a first end of which is connected between the anode of the second unidirectional element and the driving resistor, and a second end of which is grounded, is used to reduce the driving resistance value when the power switch device is turned off.

5. The circuit according to claim 3, characterized in that The protection circuit further comprises: A first capacitor, a first end of which is connected between the anode of the second unidirectional element and the gate of the power switch device, is used to reduce the conduction speed of the power switch device.

6. The circuit according to claim 1, characterized in that The circuit further comprises: A second capacitor, a first end of which is connected between the desaturation detection pin and the first resistor and a second end of which is grounded, is used to control the voltage of the desaturation detection pin, thereby controlling whether the desaturation detection pin triggers overcurrent protection.

7. The circuit according to claim 1, characterized in that The circuit further comprises: A third capacitor, a first end of which is connected to the ground pin of the driver chip, and a second end of which is connected between the positive voltage pin of the driver chip and the positive voltage power supply, and the third capacitor is used to filter the voltage provided by the positive voltage power supply; a fourth capacitor, a first end of which is connected between the positive voltage pin of the driver chip and the positive voltage power supply, and a second end of which is connected between the negative voltage pin of the driver chip and the negative voltage power supply, and the fourth capacitor is used to filter the voltage provided by the positive voltage power supply and the voltage provided by the negative voltage power supply; A fifth capacitor has a first end connected to the ground and a second end connected between the negative voltage pin of the driving chip and the negative voltage power supply. The fifth capacitor is used to filter the voltage provided by the negative voltage power supply.

8. An electrical device, comprising a power switch device and a driver chip, characterized in that: The electrical device further comprises an overcurrent protection circuit as claimed in any one of claims 1 to 7.

9. The electrical device according to claim 8, characterized in that: The electrical equipment includes at least one of the following: Air conditioners, washing machines, refrigerators, water heaters, fans, dryers, air purifiers, water purifiers, and water purifiers.

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