Overvoltage Protection Circuit of Semiconductor Device and Its Control Method

Abstract

The present application provides an overvoltage protection circuit for a semiconductor device and a control method thereof, including a first turn-off module electrically connected to the gate and the anode of the semiconductor device respectively, and the first turn-off module is used to prevent current from flowing from the gate to the cathode of the semiconductor device; an overvoltage energy extraction control module is electrically connected to the gate, the anode and the first turn-off module respectively, and the overvoltage energy extraction control module is used to control the first turn-off module to turn off when the semiconductor device is in an overvoltage state. When it is detected that the semiconductor device is in an overvoltage state, the impedance of the overvoltage energy extraction control module decreases, so that current passes through the branch where the overvoltage energy extraction control module is located and conducts from the anode of the semiconductor device to the gate, and the overvoltage energy extraction control module controls the first turn-off module to turn off, so that current enters from the gate and conducts to the cathode, completing the overvoltage protection of the semiconductor device. By using the overvoltage energy extraction control module to replace the sampling module in the prior art, the problem of the complex structure of the overvoltage protection circuit of the semiconductor device is solved.

Description

Technical Field

[0001] The present application relates to the technical field of electronic circuits, and more particularly, to an overvoltage protection circuit for a semiconductor device and a control method therefor. Background Art

[0002] In the prior art, when the voltage sampling module of the overvoltage protection circuit of a semiconductor device detects that the anode-cathode voltage V of the semiconductor device AK reaches the threshold value, the turn-off circuit is controlled to fail, ensuring that the current introduced from the anode A by the overvoltage trigger module triggers the power semiconductor device to enter the conducting state through the gate G. The power supply and control signal of the turn-off circuit both come from other components of the sampling module outside the overvoltage trigger module. The power supply and control signal of the turn-off circuit need to be obtained from components outside the overvoltage trigger module, which usually involves additional circuit components such as a power management circuit and a control logic circuit, thereby increasing the complexity and cost of the entire protection circuit. Summary of the Invention

[0003] The main object of the present application is to provide an overvoltage protection circuit for a semiconductor device and a control method therefor, so as to solve the problem of the complex structure of the overvoltage protection circuit of a semiconductor device in the prior art.

[0004] To achieve the above object, according to one aspect of the present application, there is provided an overvoltage protection circuit for a semiconductor device, including: a first turn-off module, electrically connected to the gate and the anode of the semiconductor device respectively, the first turn-off module being configured to prevent current from flowing from the gate to the cathode of the semiconductor device; an overvoltage energy extraction and control module, electrically connected to the gate, the anode and the first turn-off module respectively, the overvoltage energy extraction and control module being configured to control the first turn-off module to close when the semiconductor device is in an overvoltage state.

[0005] Optionally, the overvoltage energy extraction and control module includes: a voltage-controlled variable impedance unit and an overvoltage standby control unit, wherein the voltage-controlled variable impedance unit is electrically connected to the anode and the overvoltage standby control unit respectively, and is configured to conduct the current of the anode to the gate when the semiconductor device is in an overvoltage state; the overvoltage standby control unit is electrically connected to the first turn-off module, and is configured to provide a turn-off control signal to the first turn-off module.

[0006] Optionally, the overvoltage energy extraction and control module further includes: an overvoltage standby power supply unit, one end of the overvoltage standby power supply unit is electrically connected to the gate and the overvoltage standby control unit respectively, and is configured to supply power to the first turn-off module.

[0007] Optionally, the overvoltage protection circuit further includes a second turn-off module, which is electrically connected to the cathode and the first turn-off module respectively, and is configured to make the gate and the cathode in a conducting state.

[0008] Optionally, the voltage-controlled variable impedance unit includes any one or more of a Zener diode, a transient voltage suppression diode, a breakdown diode, and a thyristor.

[0009] Optionally, the first turn-off module includes a turn-off device and / or a capacitor.

[0010] Optionally, the first turn-off module further includes a gate driver, which is electrically connected to the turn-off device and is configured to control the turn-off device to be turned on or off.

[0011] Optionally, the turn-off device includes one of the following: HEMT and MOSFET.

[0012] According to another aspect of the present application, a control method for an overvoltage protection circuit of a semiconductor device is provided. The control method is used to control the overvoltage protection circuit, and the control method includes: obtaining the voltage between the anode and the gate of the semiconductor device; when the voltage exceeds the threshold voltage of the semiconductor device, controlling the overvoltage energy extraction control module of the overvoltage protection circuit to send a first control signal to the first turn-off module of the overvoltage protection circuit, so that the first turn-off module changes from an on state to an off state when receiving the first control signal, and prevents current from flowing from the gate to the cathode of the semiconductor device.

[0013] Optionally, the control method further includes: obtaining the voltage between the anode and the gate of the semiconductor device; when the voltage exceeds the threshold voltage of the semiconductor device, controlling the overvoltage energy extraction control module of the overvoltage protection circuit to send the first control signal to the first turn-off module and send a second control signal to the second turn-off module of the overvoltage protection circuit, so that the second turn-off module is in an on state when receiving the second control signal, and the first turn-off module is in an off state when receiving the first control signal, and prevents current from flowing from the gate to the cathode.

[0014] Applying the technical solution of the present application, a first turn-off module and an overvoltage energy extraction control module are provided in the overvoltage protection circuit. The first turn-off module is electrically connected to the gate and anode of the semiconductor device respectively, and the first turn-off module is used to prevent current from flowing from the gate to the cathode of the semiconductor device; the overvoltage energy extraction control module is electrically connected to the gate, anode and the first turn-off module respectively, and the overvoltage energy extraction control module is used to control the first turn-off module to close when the semiconductor device is in an overvoltage state. When the overvoltage energy extraction control module detects that the semiconductor device is in an overvoltage state, at this time, the voltage applied to the overvoltage energy extraction control module is higher than the voltage threshold of the overvoltage energy extraction control module, and the impedance of the overvoltage energy extraction control module will decrease, causing current to flow through the branch where the overvoltage energy extraction control module is located from the anode of the semiconductor device to the gate. The overvoltage energy extraction control module controls the first turn-off module to close, causing current to enter from the gate of the semiconductor device and conduct to the cathode, triggering the semiconductor device to enter the conduction state. At this time, the anode-cathode voltage is clamped to close to zero, thus avoiding overvoltage failure of the semiconductor device and completing overvoltage protection of the semiconductor device. By using the above-mentioned overvoltage energy extraction control module to replace the sampling module in the prior art to detect the voltage of the semiconductor device and control the first turn-off module to close for overvoltage protection of the semiconductor device, the present application solves the problem of complex structure of the overvoltage protection circuit of the semiconductor device in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings forming a part of this application are used to provide a further understanding of the application. The schematic embodiments and descriptions thereof of the application are used to explain the application and do not constitute an improper limitation of the application. In the drawings:

[0016] Figure 1 FIG. shows a schematic circuit structure diagram of an embodiment of an overvoltage protection circuit for a first semiconductor device according to the present application;

[0017] Figure 2 FIG. shows a schematic circuit structure diagram of an embodiment of an overvoltage protection circuit for a second semiconductor device according to the present application;

[0018] Figure 3 FIG. shows a schematic diagram of the structural connection mode in the overvoltage energy extraction control module in the first overvoltage protection circuit according to the present application;

[0019] Figure 4 FIG. shows a schematic diagram of the structural connection mode in the overvoltage energy extraction control module in the second overvoltage protection circuit according to the present application;

[0020] Figure 5 FIG. shows a schematic diagram of the structural connection mode in the overvoltage energy extraction control module in the third overvoltage protection circuit according to the present application;

[0021] Figure 6Shows the structural schematic diagram of various overvoltage standby control units of the present application;

[0022] Figure 7 Shows the structural schematic diagram of various voltage-controlled variable impedance units of the present application;

[0023] Figure 8 Shows the topological structural schematic diagram of the overvoltage protection circuit of the first semiconductor device of the present application;

[0024] Figure 9 Shows the topological structural schematic diagram of the overvoltage protection circuit of the second semiconductor device of the present application;

[0025] Figure 10 Shows the topological structural schematic diagram of the overvoltage protection circuit of the third semiconductor device of the present application;

[0026] Figure 11 Shows the topological structural schematic diagram of the overvoltage protection circuit of the fourth semiconductor device of the present application;

[0027] Figure 12 Shows the topological structural schematic diagram of the overvoltage protection circuit of the fifth semiconductor device of the present application;

[0028] Figure 13 Shows the topological structural schematic diagram of the overvoltage protection circuit of the sixth semiconductor device of the present application;

[0029] Figure 14 Shows the flow structural schematic diagram of the control method of the overvoltage protection circuit of a semiconductor device of the present application.

[0030] Among them, the above-mentioned drawings include the following reference numerals:

[0031] 10. First turn-off module; 11. Turn-off device; 12. Capacitor; 13. Gate driver; 20. Semiconductor device; 30. Overvoltage energy extraction control module; 31. Voltage-controlled variable impedance unit; 32. Overvoltage standby control unit; 33. Overvoltage standby power supply unit; 321. First overvoltage standby control sub-unit; 322. Second overvoltage standby control sub-unit; 331. First diode device; 332. Second diode device; 40. Second turn-off module; 50. Energy storage structure; 60. Negative temperature coefficient thermistor; 70. Refrigeration sheet. Detailed implementation manners

[0032] It should be noted that the following detailed descriptions are all illustrative and are intended to provide further descriptions of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those of ordinary skill in the technical field to which the present application belongs.

[0033] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they specify the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0034] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and do not necessarily need to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so as to implement the embodiments of the present invention described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products, or devices.

[0035] It should be understood that when an element (such as a layer, film, region, or substrate) is described as "on" another element, the element can be directly on the other element or there can also be an intermediate element. Moreover, in the description and claims, when an element is described as "connected" to another element, the element can be "directly connected" to the other element or "connected" to the other element through a third element.

[0036] As introduced in the background art, in the prior art, when the voltage sampling module of the overvoltage protection circuit of a semiconductor device detects that the anode-cathode voltage V of the semiconductor device AK reaches the threshold, the turn-off circuit is controlled to fail, ensuring that the current introduced from the anode A by the overvoltage trigger module triggers the power semiconductor device to enter the conduction state through the gate G. The power supply and control signal of the turn-off circuit both come from other components of the sampling module outside the overvoltage trigger module. The power supply and control signal of the turn-off circuit need to be obtained from components outside the overvoltage trigger module, which usually involves additional circuit components such as a power management circuit and a control logic circuit, thereby increasing the complexity and cost of the entire protection circuit. To solve the problem of the complex structure of the overvoltage protection circuit of a semiconductor device, an embodiment of the present application provides an overvoltage protection circuit for a semiconductor device and its control method.

[0037] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention.

[0038] According to one aspect of the present application, an overvoltage protection circuit for a semiconductor device is proposed, as Figure 1As shown in the figure, it includes: a first turn-off module 10, electrically connected to the gate G and the anode A of the semiconductor device 20 respectively, and the first turn-off module 10 is used to prevent current from flowing from the gate G to the cathode K of the semiconductor device 20; an overvoltage energy extraction control module 30, electrically connected to the gate G, the anode A and the first turn-off module 10 respectively, and the overvoltage energy extraction control module 30 is used to control the first turn-off module 10 to turn off when the semiconductor device 20 is in an overvoltage state.

[0039] When the overvoltage energy extraction control module detects that the semiconductor device is in an overvoltage state, the voltage applied to the overvoltage energy extraction control module at this time is higher than the voltage threshold of the overvoltage energy extraction control module, and the impedance of the overvoltage energy extraction control module will decrease, enabling current to flow through the branch where the overvoltage energy extraction control module is located from the anode of the semiconductor device to the gate. The overvoltage energy extraction control module controls the first turn-off module to turn off, causing current to flow from the gate of the semiconductor device into the cathode, triggering the semiconductor device to enter the conduction state. At this time, the anode-cathode voltage is clamped to nearly zero, thus avoiding overvoltage failure of the semiconductor device and completing overvoltage protection of the semiconductor device. In this application, by using the above-mentioned overvoltage energy extraction control module to replace the sampling module in the prior art to detect the voltage of the semiconductor device and control the first turn-off module to turn off for overvoltage protection of the semiconductor device, the problem of the complex circuit structure of the overvoltage protection circuit of the semiconductor device in the prior art is solved.

[0040] The voltage applied across the overvoltage energy extraction control module is the same as the voltage applied across the anode and cathode of the semiconductor device. Therefore, when it is detected that the semiconductor device is in an overvoltage state, it indicates that the voltage across the overvoltage energy extraction control module also exceeds the threshold voltage of the overvoltage energy extraction control module.

[0041] In the prior art, the circuit structure of the sampling module is relatively complex. In this application, using the overvoltage energy extraction control module to replace the sampling module in the prior art can not only simplify the structure of the overvoltage protection circuit, but also avoid the introduction of voltage sampling modules and other external components, increase potential fault points in the circuit, and reduce the reliability of the overvoltage protection circuit. In particular, under extreme working conditions, such as high temperature, high vibration or electromagnetic interference environments, these additional components may cause signal distortion or unstable power supply, thus affecting the performance of the overvoltage protection circuit.

[0042] In some alternative embodiments, such as Figure 2 As shown in the figure, the overvoltage protection circuit further includes a second turn-off module 40, and the second turn-off module 40 is electrically connected to the cathode K and the first turn-off module 10 respectively, and is used to make the gate G and the cathode K in a conductive state.

[0043] In the above alternative embodiment, such as Figure 2As shown, a second turn-off module 40 can also be connected to the cathode K of the semiconductor device 20. When the overvoltage energy extraction control module 30 detects that the semiconductor device 20 is in an overvoltage state, it controls the second turn-off module 40 to conduct and controls the first turn-off module 10 to turn off. Through the combined action of the first turn-off module 10 and the second turn-off module 40, the current at the anode A is prevented from flowing directly through the branch where the first turn-off module 10 is located from the branch where the overvoltage energy extraction control module 30 is located, and the current enters from the gate of the semiconductor device and flows out from the cathode, realizing effective overvoltage protection. And when the turn-off device in the first turn-off module 10 is a P-type metal-oxide-semiconductor field-effect transistor (MOSFET) or a depletion-type high electron mobility transistor (HEMT), the overvoltage energy extraction control module 30 will also supply energy to the first turn-off module 10.

[0044] Among them, the first turn-off module 10 cooperating with the second turn-off module 40 only has a turn-off device. Figure 1 In the solution with only the first turn-off module 10, the internal circuit of the first turn-off module 10 has a turn-off device and a capacitor. And when the turn-off device in the first turn-off module 10 is a P-type MOSFET or a depletion-type HEMT, the overvoltage energy extraction control module 30 will also supply energy to the first turn-off module 10.

[0045] In some alternative embodiments, as Figures 3 to 5 shown, the overvoltage energy extraction control module 30 includes: a voltage-controlled variable impedance unit 31 and an overvoltage standby control unit 32. Among them, the voltage-controlled variable impedance unit 31 is electrically connected to the anode A and the overvoltage standby control unit 32 respectively, and is used to conduct the current of the anode A to the gate G when the semiconductor device is in an overvoltage state; the overvoltage standby control unit 32 is electrically connected to the first turn-off module and is used to provide a turn-off control signal to the first turn-off module.

[0046] In the above optional embodiments, the voltage-controlled variable impedance unit and the overvoltage standby control unit are connected in series between the anode of the semiconductor device and the reference ground of the power supply of the first turn-off module. When the voltage between the anode and the cathode of the semiconductor device is greater than the preset threshold of the semiconductor device, the voltage across the voltage-controlled variable impedance unit reaches the threshold, and the impedance decreases to introduce the anode current into the gate. After introducing the anode current into the gate, the overvoltage standby control unit sends a control signal to the first turn-off module to turn off the first turn-off module, preventing the anode current from flowing to the cathode through the first turn-off module with a lower impedance and making it impossible to trigger the semiconductor device into the conduction state through the gate, resulting in the failure of overvoltage protection for the semiconductor device. Turning off the first turn-off module allows the current to flow from the gate of the semiconductor device through to the cathode, enabling the device to conduct and achieving effective overvoltage protection.

[0047] In some optional embodiments, as Figures 3 to 5 shown, the overvoltage energy extraction control module 30 further includes: an overvoltage standby power supply unit 33. One end of the overvoltage standby power supply unit 33 is electrically connected to the gate G and the overvoltage standby control unit 32 respectively, and is used to supply power to the first turn-off module. The voltage-controlled variable impedance unit 31, the overvoltage standby control unit 32, and the overvoltage standby power supply unit 33 can have various connection methods, and those skilled in the art can electrically connect the above three units according to the actual situation to make the connection method of the circuit more flexible.

[0048] In the above optional embodiments, as Figures 3 to 5 shown, the voltage-controlled variable impedance unit 31, the overvoltage standby control unit 32, and the overvoltage standby power supply unit 33 are connected in series between the anode A of the semiconductor device 20 and the reference ground of the power supply of the first turn-off module 10. The gate G of the semiconductor device 20 can be connected between the voltage-controlled variable impedance unit 31 and the overvoltage standby control unit 32 as Figure 3 shown, or the gate G can also be connected between the overvoltage standby control unit 32 and the overvoltage standby power supply unit 33 as Figure 4 shown. Figure 3 In Figure 4 the overvoltage standby control unit 32 can be exchanged with the overvoltage standby power supply unit 33, Figure 5Connected to a certain interface of the overvoltage standby power supply unit 33 as shown, the voltage-controlled variable impedance unit 31, the overvoltage standby control unit 32, and the overvoltage standby power supply unit 33 can be interchanged with each other. The overvoltage standby control unit 32 and the overvoltage standby power supply unit 33 do not need to exist simultaneously. When the switching device in the first turn-off module is an N-type MOSFET or an enhanced HEMT, the overvoltage standby power supply unit 33 can be not provided, or the overvoltage standby power supply unit 33 can also be short-circuited or opened. The connection mode of the overvoltage protection circuit in this application is diverse, and various switching devices can be used, with a wide range of applications.

[0049] In some alternative embodiments, the voltage-controlled variable impedance unit includes any one or more of a Zener diode, a transient voltage suppression diode, a breakdown diode, and a thyristor. As Figure 6 shown, the voltage-controlled variable impedance unit 31 can be as Figure 6 shown in (a) as a Metal Oxide Varistor (MOV); as Figure 6 shown in (b), the voltage-controlled variable impedance unit 31 can be a Zener diode or a Transient Voltage Suppressor (TVS) diode; the voltage-controlled variable impedance unit 31 can be a reverse-blocking Zener diode or a TVS diode (not shown in the figure); as Figure 6 shown in (c), the voltage-controlled variable impedance unit 31 can be a Zener diode in series with a reverse diode or a TVS diode in series with a reverse diode; as Figure 6 shown in (d), the voltage-controlled variable impedance unit 31 can be a Breakover Diodes (BOD); the voltage-controlled variable impedance unit 31 can be a BOD with reverse-blocking characteristics (not shown in the figure); as Figure 6 shown in (e), the voltage-controlled variable impedance unit 31 can be a BOD in series with a reverse diode; as Figure 6 shown in (f), the voltage-controlled variable impedance unit 31 can be a crowbar circuit composed of a Zener diode and a thyristor or a crowbar circuit composed of a TVS and a thyristor; as Figure 6 shown in (g), the voltage-controlled variable impedance unit 31 can be any one of a crowbar circuit composed of a reverse-blocking Zener diode and a thyristor, a crowbar circuit composed of a Zener diode in series with a reverse diode and a thyristor, and a crowbar circuit composed of a TVS diode and a thyristor; as Figure 6 shown in (h), the voltage-controlled variable impedance unit 31 can be a crowbar circuit composed of a BOD and a thyristor; the voltage-controlled variable impedance unit 31 can be a BOD with reverse-blocking characteristics (not shown in the figure); as Figure 6As shown in (i), the voltage-controlled variable impedance unit 31 can be a crowbar circuit composed of the BOD of reverse series diodes and thyristors. The voltage-controlled variable impedance unit 31 with reverse blocking characteristics and reverse series diodes is generally used for reverse blocking type power semiconductor devices, and the voltage-controlled variable impedance unit 31 without reverse blocking and reverse series diodes is generally used for asymmetric or reverse conducting type power semiconductor devices. Using the above devices as the internal devices of the voltage-controlled variable impedance unit 31 can more sensitively detect that the voltage acting on both ends of the voltage-controlled variable impedance unit 31 is greater than the threshold voltage of the voltage-controlled variable impedance unit 31. When the voltage across the voltage-controlled variable impedance unit 31 is greater than the threshold voltage of the voltage-controlled variable impedance unit 31, the resistance of the voltage-controlled variable impedance unit 31 itself will decrease, and then the current of the anode A will be conducted to the gate, and the current will flow into the semiconductor device from the gate and out from the cathode, better completing the overvoltage protection of the semiconductor device.

[0050] As Figure 7 shown, the overvoltage standby control unit 32 can be a transformer, as Figure 7 shown in (a), an optocoupler or an optical fiber, as Figure 7 shown in (b). By using the above devices for the overvoltage standby control unit 32, it can better provide a control voltage signal for the first turn-off module and control the first turn-off module to turn off.

[0051] At first, the semiconductor device is in the conducting state, and the current is injected into the semiconductor device from the anode of the semiconductor device and flows out from the cathode. There are two methods to turn off the semiconductor device. The first is as Figures 8 to 10 shown, when there is only the first turn-off module 10 in the overvoltage protection circuit, and the second is as Figure 11 shown, when there are the first turn-off module 10 and the second turn-off module 40 in the overvoltage protection circuit.

[0052] In some alternative embodiments, as Figures 8 to 11 shown, the first turn-off module 10 includes a turn-off device 11 and / or a capacitor 12. When the first turn-off module 10 is used in cooperation with the second turn-off module 40, the first turn-off module 10 may only have a turn-off device. When there is only the first turn-off module 10 in the circuit, the internal circuit of the first turn-off module 10 has a turn-off device and a capacitor. The capacitor has positive and negative poles. During the process of the semiconductor device turning from conduction to turn-off, the capacitor can provide an impedance lower than that of the branch where the cathode of the semiconductor device is located for the branch where the first turn-off module 10 is located, so that the current entering the semiconductor device from the anode flows out from the gate and flows through the branch where the first turn-off module 10 is located. The above two methods can be flexibly applied to smoothly turn off the device.

[0053] In some alternative embodiments, the above-mentioned turn-off device includes one of the following: HEMT and MOSFET. Among them, MOSFET includes N-type MOSFET and P-type MOSFET, and HEMT includes depletion type and enhancement type. The depletion-type HEMT and P-type MOSFET are turned on in the negative voltage state, and the enhancement-type HEMT and N-type MOSFET are turned on in the positive voltage state. Different types of turn-off devices can be used in the overvoltage protection circuit in this application, and the application range is wide.

[0054] In some embodiments, as Figures 8 to 10 shown, the first turn-off module 10 includes a turn-off device 11 and a capacitor 12. When turning off the semiconductor device 20, the turn-off device 11 is turned on, the negative electrode of the capacitor 12 is connected to the gate G, and the positive electrode of the capacitor 12 is connected to the cathode K. As a result, the voltage drop across the branch where the first turn-off module 10 is located is negative, which is lower than the voltage drop of 0 across the branch where the cathode K is located. Therefore, the impedance of the branch where the first turn-off module 10 is located is lower, and the current of the semiconductor device 20 can be diverted from the anode A to the gate G, completing the commutation of the semiconductor device 20 and turning off the semiconductor device 20. The first turn-off module 10 and the semiconductor device 20 form an Integrated Gate-Commutated Thyristor (IGCT).

[0055] In some embodiments, as Figure 8 shown, the first turn-off module 10 includes a turn-off device 11 and a capacitor 12, and the turn-off device is an N-type MOSFET or an enhancement-type HEMT. The overvoltage energy extraction control module 30 only contains a voltage-controlled variable impedance unit 31 and an overvoltage standby control unit 32. The working principle is as follows: when the semiconductor device 20 is in the off state or blocking state, when it is detected that the anode-cathode voltage V AK of the semiconductor device 20 exceeds the threshold of the voltage-controlled variable impedance unit 31, the impedance of the voltage-controlled variable impedance unit 31 decreases, and current is injected from the anode A through the primary side of the optocoupler of the overvoltage standby control unit 32 to the gate G of the semiconductor device 20. The secondary side of the optocoupler of the overvoltage standby control unit 32 conducts, grounding the gate of the turn-off device 11 of the first turn-off module 10 to ensure the turn-off of the turn-off device 11. As a result, the first turn-off module 10 is controlled to fail, enabling the current to flow smoothly from the anode A to the gate G and be injected into the semiconductor device, and the semiconductor device 20 can be triggered to conduct, achieving effective overvoltage protection for the semiconductor device 20.

[0056] In some embodiments, as Figure 9 shown, the first turn-off module 10 includes a turn-off device 11 and a capacitor 12, and the turn-off device is a P-type MOSFET or a depletion-type HEMT ( Figure 9The device shown in the figure is a depletion-mode HEMT). The overvoltage energy extraction control module 30 includes a voltage-controlled variable impedance unit 31, an overvoltage standby control unit 32, and an overvoltage standby energy supply unit 33. The working principle is as follows: when the semiconductor device 20 is in the off state or the blocking state, when detecting the anode-cathode voltage V of the semiconductor device 20 AK exceeds the threshold of the overvoltage-controlled variable impedance unit 31, the impedance of the voltage-controlled variable impedance unit 31 decreases, and a current is injected from the anode A through the primary side of the optocoupler of the overvoltage standby control unit 32 to the gate G of the semiconductor device 20. The secondary side of the optocoupler of the overvoltage standby control unit 32 conducts, connecting the gate of the off-device 11 to the reference ground. The overvoltage standby energy supply unit 33 applies a voltage to the source of the off-device 11, clamping the voltage between the gate (reference ground) and the source of the off-device 11 to less than the turn-off drive voltage of the off-device 11, ensuring the turn-off of the off-device 11, thereby causing the first turn-off module 10 to be controlled to fail, enabling the current to flow smoothly from the anode A to the gate G and injecting into the semiconductor device, and the semiconductor device 20 can be triggered to conduct, realizing effective overvoltage protection for the semiconductor device 20.

[0057] In some embodiments, as Figure 10 shown, the first turn-off module 10 includes an off-device 11, a capacitor 12, and a gate driver 13. The gate driver 13 is electrically connected to the off-device 11 and is used to control the off-device 11 to turn on or off. The capacitor 12 is used to make the first turn-off module 10 have a lower voltage drop. The off-device 11 is a depletion-mode HEMT. The overvoltage energy extraction control module 30 includes a voltage-controlled variable impedance unit 31, an overvoltage standby control unit 32, and an overvoltage standby energy supply unit 33. The working principle is as follows: when the semiconductor device 20 is in the off state or the blocking state, when detecting the anode-cathode voltage V of the semiconductor device 20 AK exceeds the threshold of the overvoltage-controlled variable impedance unit 31, the impedance of the voltage-controlled variable impedance unit 31 decreases, and a current is injected from the anode A through the primary side of the optocoupler of the overvoltage standby control unit 32 to the gate G of the semiconductor device 20. The secondary side of the optocoupler of the overvoltage standby control unit 32 conducts, connecting the control input of the gate driver 13 to the first reference ground (the first reference ground is the ground connected to the overvoltage standby control unit 32). The overvoltage standby energy supply unit 33 includes a first diode device 331 and a second diode device 332. The diode device can be a Zener diode or a TVS diode. The first diode device 331 clamps the first reference ground to the low voltage rail of the gate driver 13, and the second diode device 332 clamps the second reference ground ( Figure 10The triangle connected to the middle gate driver 13 is clamped to the high-voltage rail of the gate driver 13, so that the gate driver 13 outputs a turn-off voltage signal to the turn-off device 11, ensuring that the turn-off device 11 is reliably turned off under the high driving ability of the gate driver 13, making the first turn-off module 10 controlled to fail, and realizing effective overvoltage protection for the semiconductor device 20.

[0058] In some embodiments, as Figure 11 shown, the first turn-off module 10 only includes the turn-off device 11. When turning off the semiconductor device 20, the overvoltage energy extraction control module 30 controls the second turn-off module 40 to turn off, and the first turn-off module 10 is turned on, and the current is commutated to the gate G, and then the semiconductor device 20 is turned off. The first turn-off module 10, the second turn-off module 40 and the semiconductor device 20 form an Emitter Turn-Off Thyristor (ETO).

[0059] In some embodiments, as Figure 11 shown, the turn-off device of the first turn-off module 10 is a depletion-type HEMT. The overvoltage energy extraction control module 30 includes a voltage-controlled variable impedance unit 31, an overvoltage standby control unit 32 and an overvoltage standby power supply unit 33. The overvoltage standby control unit 32 includes a first overvoltage standby control subunit 321 and a second overvoltage standby control subunit 322. The working principle is as follows. When the semiconductor device 20 is in the off state, when the anode-cathode voltage V AK of the semiconductor device 20 exceeds the threshold of the voltage-controlled variable impedance unit 31, the impedance of the voltage-controlled variable impedance unit 31 decreases, and current is injected into the gate G of the semiconductor device 20 from the anode A through the primary side of the optocoupler of the first overvoltage standby control subunit 321, the primary side of the optocoupler of the second overvoltage standby control subunit 322 and the overvoltage standby power supply unit 33. The overvoltage standby power supply unit 33 is electrically connected to the first reference ground that generates a voltage exceeding the gate threshold voltage of the second turn-off module 40 relative to the cathode K. The secondary side of the optocoupler of the first overvoltage standby control subunit 321 conducts, connecting the gate of the turn-off device 11 (N-channel MOSFET) in the first turn-off module 10 to the cathode K, and the first turn-off module 10 is controlled to fail (turn off); the secondary side of the optocoupler of the second overvoltage standby control subunit 322 conducts, connecting the gate of the turn-off device (N-channel MOSFET) in the second turn-off module 40 to the first reference ground, and the second turn-off module 40 is controlled to be effective (turn on), and the current injected into the gate G flows out from the cathode K through the second turn-off module 40, triggering the semiconductor device 20 to conduct, and realizing reliable overvoltage protection.

[0060] The overvoltage protection circuit introduced above is a passive circuit, as Figure 12As shown, a energy storage structure 50 is connected in parallel at the overvoltage standby power supply unit 33 in the overvoltage protection circuit, so that the overvoltage protection circuit is transformed into an active circuit. When the semiconductor device 20 is in an overvoltage state, the impedance of the voltage-controlled variable impedance unit 31 decreases, and the branch where the voltage-controlled variable impedance unit 31 is located is turned on, conducting current from the anode A to the gate G. A part of this current is used to supply power to the first turn-off module 10 and other devices in the circuit, and another part of the current enters the energy storage structure 50 and is stored by the energy storage structure 50. The stored part of the current is used to maintain the voltage-controlled variable impedance unit 31 in a low-resistance state and keep it conducting for a period of time. The first turn-off module 10 is in a closed state, so that the semiconductor device 20 can continue to be in a conducting state, and the reliable conduction degree of the semiconductor device 20 can be improved.

[0061] Since the voltage-controlled variable impedance unit will withstand overvoltage, the operating temperature at the voltage-controlled variable impedance unit will be relatively high. If the temperature of the voltage-controlled variable impedance unit rises too high, there will be a large deviation between the overvoltage trigger threshold of the voltage-controlled variable impedance unit and the standard threshold, resulting in the semiconductor device not being protected by overvoltage in time and being damaged. As Figure 13 shown, an energy storage structure 50, a negative temperature coefficient thermistor 60, and a refrigeration chip 70 are provided in the overvoltage protection circuit. Among them, the negative temperature coefficient thermistor 60 is connected in series between the refrigeration chip 70 and the energy storage structure 50, and the negative temperature coefficient thermistor 60 and the refrigeration chip 70 are relatively close to the position of the voltage-controlled variable impedance unit 31 in the circuit, and can detect the temperature change of the voltage-controlled variable impedance unit 31. When the semiconductor device 20 is in an overvoltage state, the impedance of the voltage-controlled variable impedance unit 31 decreases, conducting current from the anode A to the gate G. A part of this current is used to supply power to the first turn-off module 10 and other devices in the circuit, and another part of the current enters the energy storage structure 50 and is stored by the energy storage structure 50. When the temperature of the voltage-controlled variable impedance unit 31 rises, the resistance value of the negative temperature coefficient thermistor 60 will decrease, so that the discharge amount of the energy storage structure 50 to the refrigeration chip 70 will increase, and the refrigeration effect of the refrigeration chip 70 will be enhanced, thereby cooling the voltage-controlled variable impedance unit 31 and keeping the temperature of the voltage-controlled variable impedance unit 31 in a stable state, so that the overvoltage trigger threshold remains stable and the overvoltage protection circuit can operate normally. Figure 12 and Figure 13 For structures not mentioned in Figure 9 and Figure 10 refer to the description in

[0062] Figure 14 is a flowchart of a control method for an overvoltage protection circuit of a semiconductor device according to an embodiment of the present application. As Figure 14 shown, the method includes the following steps:

[0063] Step S201: Obtain the voltage between the anode and the gate of the semiconductor device.

[0064] Specifically, when the semiconductor device is in the off state, detect and obtain the voltage between the anode and the gate (equivalent to the anode and the cathode) to prevent the voltage of the semiconductor device from being too high and causing breakdown.

[0065] Step S202: When the voltage exceeds the threshold voltage of the semiconductor device, control the overvoltage energy extraction control module of the overvoltage protection circuit to send a first control signal to the first turn-off module of the overvoltage protection circuit, so that the first turn-off module changes from the on state to the off state when receiving the first control signal, preventing current from flowing from the gate to the cathode of the semiconductor device.

[0066] Specifically, once it is detected that the voltage between the anode and the gate of the semiconductor device exceeds the threshold voltage of the semiconductor device, overvoltage protection of the semiconductor device is required. Since the voltage between the anode and the gate of the semiconductor device is the same as the voltage applied across the overvoltage energy extraction control module, the voltage across the overvoltage energy extraction control module also exceeds the threshold voltage at this time, and the impedance of the voltage-controlled variable impedance unit will decrease, and current will flow through the branch where the overvoltage energy extraction control module is located. When the turn-off device in the first turn-off module is a positive voltage turn-off device, control the overvoltage standby control unit in the overvoltage energy extraction control module to send a first control signal to the first turn-off module to turn off the first turn-off module, so that the current entering the branch where the overvoltage energy extraction control module is located enters the semiconductor device from the gate and flows out of the semiconductor device from the cathode, triggering the semiconductor device, and thus completing effective overvoltage protection.

[0067] Specifically, when the turn-off device in the first turn-off module is a negative voltage turn-off device, control the overvoltage standby control unit in the overvoltage energy extraction control module to send a first control signal to the first turn-off module, and control the overvoltage standby power supply unit in the overvoltage energy extraction control module to supply power to the first turn-off module to turn off the first turn-off module, so that the current entering the branch where the overvoltage energy extraction control module is located enters the semiconductor device from the gate, triggering the semiconductor device, and thus completing effective overvoltage protection.

[0068] Through this embodiment, an overvoltage energy extraction control module can be used to replace the sampling module in the prior art to detect the voltage applied to the semiconductor device. When it is detected that the semiconductor device is in an overvoltage state, the voltage across the overvoltage energy extraction control module also synchronously exceeds its own voltage threshold. At this time, the impedance of the overvoltage energy extraction control module will decrease, causing the current to flow through the branch where the overvoltage energy extraction control module is located from the anode of the semiconductor device to the gate, and controlling the first turn-off module to turn off, so that the current flows from the gate into the semiconductor device, triggering the semiconductor device to enter the conduction state from the off state. At this time, the anode-cathode voltage is clamped to nearly zero, thus avoiding overvoltage failure of the semiconductor device, completing the overvoltage protection of the semiconductor device in the off state, improving the reliability of the overvoltage protection circuit, and the overvoltage protection current in this application can be applied to various turn-off devices, with stronger versatility. Using the overvoltage energy extraction control module to replace the sampling module in the prior art solves the problem of the complex structure of the overvoltage protection circuit of semiconductor devices in the prior art.

[0069] In order to enable those skilled in the art to more clearly understand the technical solution of this application, the implementation process of the control method of the overvoltage protection circuit of the semiconductor device of this application will be described in detail below in conjunction with specific embodiments.

[0070] In some optional implementation manners, the control method further includes: obtaining the voltage between the anode and the gate of the semiconductor device; in the case where the voltage exceeds the threshold voltage of the semiconductor device, controlling the overvoltage energy extraction control module of the overvoltage protection circuit to send a first control signal to the first turn-off module and send a second control signal to the second turn-off module of the overvoltage protection circuit, so that the second turn-off module is in an on state when receiving the second control signal, and the first turn-off module is in an off state when receiving the first control signal, preventing the current from flowing from the gate to the cathode.

[0071] In the above optional implementation manner, the method of making the current flow from the anode through the branch where the overvoltage energy extraction control module is located and enter the semiconductor device through the gate can also be a way of the combined action of the first turn-off module and the second turn-off module. The turn-off devices in the first turn-off module and the second turn-off module can also be of various types, such as positive voltage turn-off devices and negative voltage turn-off devices. The various branch combinations and the selection of various devices make the form of the overvoltage protection circuit diverse.

[0072] When the turn-off device in the first turn-off module is a positive voltage turn-off device, the self-impedance of the voltage-controlled variable impedance unit in the overvoltage energy extraction control module will decrease, and the current will flow through the branch where the overvoltage energy extraction control module is located. The overvoltage standby control unit in the overvoltage energy extraction control module is controlled to send a first control signal to the first turn-off module to turn off the first turn-off module, and the overvoltage standby control unit in the overvoltage energy extraction control module is controlled to send a second control signal to the second turn-off module to turn on the second turn-off module, so that the current entering the branch where the overvoltage energy extraction control module is located enters the semiconductor device from the gate, triggering the semiconductor device and thus completing effective overvoltage protection. The principle of controlling the second turn-off module to turn on can refer to the description of Figure 11

[0073] When the turn-off device in the first turn-off module is a negative voltage turn-off device, the overvoltage standby control unit in the overvoltage energy extraction control module is controlled to send a first control signal to the first turn-off module, and the overvoltage standby energy supply unit in the overvoltage energy extraction control module is controlled to supply energy to the first turn-off module to turn off the first turn-off module. The overvoltage standby control unit in the overvoltage energy extraction control module is controlled to send a second control signal to the second turn-off module to turn on the second turn-off module, so that the current entering the branch where the overvoltage energy extraction control module is located enters the semiconductor device from the gate, triggering the semiconductor device and thus completing effective overvoltage protection. The process of turning off the first turn-off module can refer to the description in Figure 9

[0074] From the above description, it can be seen that the overvoltage protection circuit of the semiconductor device provided by this application achieves the following technical effects:

[0075] 1) When it is detected that the semiconductor device is in an overvoltage state, the overvoltage energy extraction control module will reduce its own impedance, so that the current passes through the branch where the overvoltage energy extraction control module is located and conducts from the anode to the gate of the semiconductor device, and controls the first turn-off module to turn off to achieve overvoltage protection, so that the current enters from the gate of the semiconductor device and conducts to the cathode, triggering the semiconductor device to enter the conduction state. At this time, the anode-cathode voltage is clamped to be close to zero, thus avoiding overvoltage failure of the semiconductor device and completing overvoltage protection of the semiconductor device. The overvoltage energy extraction control module is used to replace the sampling module in the prior art to detect the anode-cathode voltage of the semiconductor device, simplifying the composition of the overvoltage protection circuit.

[0076] 2) Using the overvoltage energy extraction control module to replace the sampling module in the prior art in this application can also avoid the introduction of voltage sampling modules and other external components, increase potential fault points in the circuit, and reduce the reliability of the overvoltage protection circuit.

[0077] ​​3) The voltage-controlled variable impedance unit, overvoltage standby control unit, and overvoltage standby power supply unit can have multiple connection methods and can use multiple switching devices, making the circuit connection method more flexible and having a wide range of applications.

[0078] The above are only the preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An overvoltage protection circuit for a semiconductor device, characterized in that: include: A first shutoff module, electrically connected to the gate and cathode of the semiconductor device respectively, and the first shutoff module is used to prevent current from flowing from the gate to the cathode of the semiconductor device; An overvoltage energy acquisition control module is electrically connected to the gate, the anode and the first shutdown module, respectively. The overvoltage energy acquisition control module is used to control the first shutdown module to be turned off when the semiconductor device is in an overvoltage state. The overvoltage energy acquisition control module includes: a voltage-controlled variable impedance unit and an overvoltage standby control unit, wherein the voltage-controlled variable impedance unit is electrically connected to the anode and the overvoltage standby control unit, respectively, and is used to conduct the current of the anode to the gate when the semiconductor device is in an overvoltage state; the overvoltage standby control unit is electrically connected to the first shutdown module, and is used to provide a shutdown control signal to the first shutdown module.

2. The overvoltage protection circuit according to claim 1, characterized in that: The overvoltage energy control module further includes: an overvoltage standby energy supply unit, one end of which is electrically connected to the gate and the overvoltage standby control unit respectively, for supplying energy to the first shutdown module.

3. The overvoltage protection circuit according to claim 1, characterized in that: The overvoltage protection circuit further includes a second shutdown module, which is electrically connected to the cathode and the first shutdown module respectively, and is used to make the gate and the cathode in a conducting state.

4. The overvoltage protection circuit according to claim 1, characterized in that: The voltage-controlled variable impedance unit includes any one or more of a Zener diode, a transient voltage suppressor diode, a breakdown diode and a thyristor.

5. The overvoltage protection circuit according to claim 1, characterized in that: The first shutdown module includes a shutdown device and / or a capacitor.

6. The overvoltage protection circuit according to claim 5, characterized in that: The first shutdown module further includes a gate driver, which is electrically connected to the shutdown device and is used to control the shutdown device to be turned on or off.

7. The overvoltage protection circuit according to claim 5, characterized in that: The turn-off device includes one of the following: HEMT and MOSFET.

8. A method for controlling an overvoltage protection circuit of a semiconductor device, characterized in that: The control method is used to control the overvoltage protection circuit according to any one of claims 1 to 7, and the control method comprises: Obtaining the voltage between the anode and gate of the semiconductor device; When the voltage exceeds the threshold voltage of the semiconductor device, the overvoltage energy control module that controls the overvoltage protection circuit sends a first control signal to the first shutdown module of the overvoltage protection circuit, so that the first shutdown module changes from an on state to a off state when receiving the first control signal, thereby preventing current from flowing from the gate to the cathode of the semiconductor device.

9. The control method according to claim 8, characterized in that: The control method further comprises: Obtaining the voltage between the anode and gate of the semiconductor device; When the voltage exceeds the threshold voltage of the semiconductor device, the overvoltage energy control module that controls the overvoltage protection circuit sends the first control signal to the first shutdown module, and sends the second control signal to the second shutdown module of the overvoltage protection circuit, so that the second shutdown module is in the turned-on state when receiving the second control signal, and the first shutdown module is in the turned-off state when receiving the first control signal, so as to prevent current from flowing from the gate to the cathode.

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