Short - circuit Detection Circuit and Method for SiC MOSFET

Abstract

The technical solution of this application provides a short-circuit detection circuit and method for a SiC MOSFET. The short-circuit detection circuit includes: an output-side logic control module, which is used to receive and output the drive pulse signal of the SiC MOSFET, and is also used to output a control signal synchronized with the drive pulse signal; an output-stage power amplification circuit, which is electrically connected to the output-side logic control module and is configured to amplify the drive pulse signal and output it to the SiC MOSFET; a short-circuit detection module, which is electrically connected to the output-side logic control module and the drain of the SiC MOSFET, and is configured to receive the control signal and obtain a reference voltage signal, and at the same time obtain the drain-source voltage signal of the SiC MOSFET, and output a detection result signal to the output-side logic control module based on the drain-source voltage signal and the reference voltage signal. The short-circuit detection circuit of the technical solution of this application can perform dynamic short-circuit monitoring on the circuit where the SiC MOSFET is located.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, and in particular, to a short - circuit detection circuit and method for SiC MOSFETs. Background Art

[0002] Power electronic power converters, as important devices for electrical energy utilization, play an important role in production and life. The core of power electronic power converters is power semiconductor devices, which largely determine the performance of power electronic power converters. Currently, most power semiconductor devices are made of Si semiconductor materials, and their characteristics have approached the theoretical limit, becoming a bottleneck for the further development of power electronic power converters. Compared with Si power devices, SiC power devices have more excellent characteristics: SiC power devices have a higher switching speed, can operate at a higher junction temperature, and can simultaneously achieve high frequency, high voltage, and large current. These characteristics can significantly improve the performance of semiconductor power converters, obtain higher electrical energy conversion efficiency, achieve higher power density, and reduce system costs, etc.

[0003] In a power electronic converter, the control signal sent by the microcontroller belongs to a weak - signal, which cannot directly drive the power semiconductor device. A drive circuit needs to be set between the microcontroller and the power semiconductor device. The drive circuit mainly shapes and amplifies the weak - electrical control signal sent by the microcontroller to achieve the on - off control of the power semiconductor device; when a fault occurs in the power semiconductor device and its circuit, the drive circuit also needs to send the fault information back to the microcontroller. Therefore, the drive circuit is a bridge for the interaction between the weak - electrical control signal and the strong - electrical power loop, and the reliability of the drive circuit directly affects the overall reliability of the power electronic converter.

[0004] SiC MOSFETs are mainly used in high - voltage applications and have high requirements for reliability. If a short - circuit occurs in the circuit where they are located, it will cause relatively serious consequences, and it is necessary to perform short - circuit detection and protection. Currently, there are still many problems when using desaturation detection for short - circuit protection. For example, if the blanking time is short, it is easy to misoperate; if the blanking time is long, it is difficult to safely turn off within the specified maximum short - circuit time. The blanking time is determined by the value of the blanking capacitor, but it is difficult to select the value of the blanking capacitor; after determining the value of the blanking capacitor, it is also affected by temperature, and at the same time, the high - voltage diode in the desaturation detection circuit is a strong interference source. Summary of the Invention

[0005] The technical problem to be solved by this application is to provide a short - circuit detection circuit and method for SiC MOSFETs, which can monitor the short - circuit of the circuit where the SiC MOSFET is located and overcome the problems existing in the existing desaturation detection.

[0006] To solve the above technical problems, the present application provides a short-circuit detection circuit for a SiC MOSFET, including: an output-side logic control module, configured to receive and output the drive pulse signal of the SiC MOSFET, and further configured to output a control signal synchronized with the drive pulse signal; an output-stage power amplification circuit, electrically connected to the output-side logic control module, and configured to amplify the drive pulse signal and output it to the SiC MOSFET; a short-circuit detection module, electrically connected to the output-side logic control module and the drain of the SiC MOSFET, and configured to receive the control signal and obtain a reference voltage signal, and at the same time obtain the drain-source voltage signal of the SiC MOSFET, and output a detection result signal to the output-side logic control module based on the drain-source voltage signal and the reference voltage signal.

[0007] In some embodiments of the present application, the short-circuit detection module is configured to compare the drain-source voltage signal with the reference voltage signal. When the drain-source voltage signal is greater than the reference voltage signal, the operational amplifier signal flips, and the short-circuit detection module outputs a short-circuit signal to the output-side logic control module.

[0008] In some embodiments of the present application, the short-circuit detection module is further configured to compare the drain-source voltage signal with the reference voltage signal. When the drain-source voltage signal is less than or equal to the reference voltage signal, the operational amplifier signal does not flip.

[0009] In some embodiments of the present application, the short-circuit detection module includes: a comparator, including a first input terminal, a second input terminal, and an output terminal, wherein the output terminal is electrically connected to the output-side logic control module; a drain-source voltage signal source circuit, electrically connected to the first input terminal; a reference voltage signal source circuit, electrically connected to the second input terminal.

[0010] In some embodiments of the present application, the drain-source voltage signal source circuit includes: a fifth resistor, the first end of the fifth resistor is electrically connected to the drain of the SiC MOSFET, and a second capacitor is also electrically connected across the two ends of the fifth resistor; a sixth resistor, the first end of the sixth resistor is electrically connected to the second end of the fifth resistor, and a third capacitor is also electrically connected across the two ends of the sixth resistor; a seventh resistor, the first end of the seventh resistor is electrically connected to the second end of the sixth resistor, the second end is electrically connected to the first input terminal, and a fourth capacitor is also electrically connected across the two ends of the seventh resistor; an eighth resistor, the first end of the eighth resistor is electrically connected to the first input terminal, and the second end is connected to the output-side ground, and a fifth capacitor is also electrically connected across the two ends of the eighth resistor.

[0011] In some embodiments of the present application, the reference voltage signal source circuit includes: a third MOS transistor, the gate of the third MOS transistor is electrically connected to the output-side logic control module, the source is connected to the output-side ground, and the third MOS transistor is controlled by the control signal; a first zener diode, the anode of the first zener diode is electrically connected to the drain of the third MOS transistor; a ninth resistor, the first end of the ninth resistor is electrically connected to the cathode of the first zener diode, and the second end is electrically connected to the second input terminal; a sixth capacitor, the first end of the sixth capacitor is electrically connected to the second input terminal, and the second end is connected to the output-side ground; a tenth resistor, the first end of the tenth resistor is electrically connected to the DC positive voltage, and the second end is electrically connected to the second input terminal.

[0012] In some embodiments of the present application, the short-circuit detection circuit further includes: an auxiliary detection module located between the Kelvin pin and the source pin of the SiC MOSFET for detecting the current change rate of the SiC MOSFET.

[0013] In some embodiments of the present application, the auxiliary detection module includes: a second diode, the anode of the second diode is connected to the output-side ground; an eleventh resistor, the first end of the eleventh resistor is electrically connected to the cathode of the second diode, and the second end is electrically connected to the source of the SiC MOSFET; a twelfth resistor, the first end of the twelfth resistor is electrically connected to the cathode of the second diode; a seventh capacitor, the first end of the seventh capacitor is electrically connected to the second end of the twelfth resistor, and the second end is electrically connected to the source of the SiC MOSFET; a transformer, the primary side of the transformer is electrically connected to both ends of the seventh capacitor, and one end of the secondary side is electrically connected to the output-side logic control module, and the other end is connected to the output-side ground.

[0014] In some embodiments of the present application, the output-stage power amplifier circuit includes a push-pull drive circuit composed of a PMOS transistor and an NMOS transistor, or includes a push-pull drive circuit composed of an NPN and a PNP transistor.

[0015] In some embodiments of the present application, the output-stage power amplifier circuit includes: an amplifier, the input terminal of the amplifier is electrically connected to the output-side logic control module, and the amplifier is also electrically connected to the DC positive voltage, the DC negative voltage, and the output-side ground; a PMOS transistor, the source of the PMOS transistor is electrically connected to the DC voltage, the gate is electrically connected to the output terminal of the amplifier, and the drain is electrically connected to the gate of the SiC MOSFET through a third resistor; an NMOS transistor, the source of the NMOS transistor is electrically connected to the DC negative voltage, the gate is electrically connected to the output terminal of the amplifier, and the drain is electrically connected to the gate of the SiC MOSFET through a first resistor.

[0016] In some embodiments of the present application, the short - circuit detection circuit further includes an input - side logic control module, which is configured to receive the drive pulse signal of the SiC MOSFET and output it to the output - side logic control module, and the output - side logic control module also feeds back the detection result signal to the input - side logic control module.

[0017] In some embodiments of the present application, a second encoding and decoding module is also electrically connected between the input - side logic control module and the output - side logic control module. The second encoding and decoding module includes: a feedback encoding module electrically connected to the output - side logic control module; a feedback decoding module, which is signal - isolated from the feedback encoding module and electrically connected to the input - side logic control module.

[0018] The present application also provides a short - circuit detection method for a SiC MOSFET, including: the output - side logic control module receives the drive pulse signal of the SiC MOSFET and outputs it, and is also configured to output a control signal synchronized with the drive pulse signal; the output - stage power amplification circuit amplifies the drive pulse signal and outputs it to the SiC MOSFET; the short - circuit detection module receives the control signal and obtains a reference voltage signal, and at the same time acquires the drain - source voltage signal of the SiC MOSFET, and outputs a detection result signal to the output - side logic control module based on the drain - source voltage signal and the reference voltage signal.

[0019] In some embodiments of the present application, the method of outputting a detection result signal to the output - side logic control module based on the drain - source voltage signal and the reference voltage signal includes: comparing the drain - source voltage signal with the reference voltage signal. When the drain - source voltage signal is greater than the reference voltage signal, the operational - amplifier signal flips, and the short - circuit detection module outputs a short - circuit signal to the output - side logic control module.

[0020] In some embodiments of the present application, when the drain - source voltage signal is less than the reference voltage signal, the operational - amplifier signal does not flip.

[0021] The short - circuit detection circuit of the technical solution of the present application realizes dynamic detection of the circuit by setting a short - circuit detection module, and the control signal of the short - circuit detection module is synchronized with the drive pulse signal, so that the reference voltage signal has an adjustable characteristic, and at the same time, it can solve the problems of difficult parameter setting of the current short - circuit detection circuit and interference with other devices. Description of the Drawings

[0022] The following drawings detail the exemplary embodiments disclosed in this application. The same reference numerals in the several views of the drawings denote similar structures. Those of ordinary skill in the art will understand that these embodiments are non-limiting, exemplary embodiments, and the drawings are for illustrative and descriptive purposes only and are not intended to limit the scope of this application. Embodiments in other ways may also achieve the inventive intent of this application. It should be understood that the drawings are not drawn to scale. Wherein:

[0023] Figure 1 is a schematic structural diagram of a short-circuit detection circuit for a SiC MOSFET according to an embodiment of this application;

[0024] Figure 2 is a schematic structural diagram of another short-circuit detection circuit for a SiC MOSFET according to an embodiment of this application;

[0025] Figure 3 are the change curves of the source-drain voltage signal and the reference voltage signal when the SiC MOSFET turns from off to on and a short circuit occurs in the circuit where it is located;

[0026] Figure 4 is a schematic structural diagram of yet another short-circuit detection circuit for a SiC MOSFET according to an embodiment of this application;

[0027] Figure 5 is a schematic structural diagram of the output stage power amplification circuit according to an embodiment of this application;

[0028] Figure 6 is a schematic structural diagram of still another short-circuit detection circuit for a SiC MOSFET according to an embodiment of this application. Detailed Embodiments

[0029] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some examples or embodiments of this application. For those of ordinary skill in the art, without creative efforts, this application can also be applied to other similar scenarios based on these drawings. Unless obvious from the language context or otherwise stated, the same reference numerals in the drawings represent the same structure or operation.

[0030] It should be understood that the "module" and "circuit" used herein are a way to distinguish different components, elements, parts, portions or assemblies at different levels. However, if other words can achieve the same purpose, the said words can be replaced by other expressions.

[0031] The terms used in this application are for the purpose of describing specific example embodiments only and are not restrictive. For example, unless the context clearly dictates otherwise, as used herein, the singular forms "a", "an", and "the" may also include the plural forms. When used in this specification, the terms "comprises", "comprising", and / or "containing" mean that the associated integers, steps, operations, elements, and / or components exist, but do not preclude the existence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When describing the association of different components in this specification, it can be a direct relationship or an indirect relationship. For example, "A and B are connected" can mean that A and B are directly connected, or that A and B are indirectly connected through other components.

[0032] In view of the following description, the features disclosed in this specification and other features, as well as the operations and functions of the relevant elements of the structure, and the combination and manufacturing economy of the components can be significantly improved. Referring to the accompanying drawings, all of which form a part of the disclosure of this specification. However, it should be clearly understood that the drawings are for illustrative and descriptive purposes only and are not intended to limit the scope of the disclosure of this specification. Flowcharts are used in this application to illustrate the operations performed by the system according to the embodiments of this application. It should be understood that the previous or subsequent operations are not necessarily executed precisely in sequence. On the contrary, the steps can be processed in reverse order or simultaneously. At the same time, other operations can also be added to these processes, or one or more steps can be removed from these processes.

[0033] The following description provides specific application scenarios and requirements of this application, aiming to enable those skilled in the art to manufacture and use the content of this application. For those skilled in the art, various partial modifications to the disclosed embodiments are obvious, and the general principles defined here can be applied to other embodiments and applications without departing from the spirit and scope of this application. Therefore, this application is not limited to the disclosed embodiments, but rather to the broadest scope consistent with the claims.

[0034] Currently, short-circuit protection is not provided in the SiC MOSFET circuit design, and there are also some designs that set short-circuit protection in applications, that is, they follow the protection principle and design of Si IGBT devices and set static desaturation detection protection. Under normal operating conditions, when the IGBT device is conducting, it operates in the saturation region, and when it is turned off, it operates in the cut-off region. The turn-on and turn-off processes need to cross the amplification region. When a short circuit occurs in the IGBT, its operating point will enter the amplification region from the saturation region, that is, the region of high voltage and large current, which is called desaturation. By detecting the voltage V between the collector and emitter of the IGBT CE, the short circuit of the IGBT can be recognized, and the implementation method is generally to adopt the static desaturation detection protection of the diode.

[0035] During detection, the blanking time can be set through the blanking capacitor, so that the SiC MOSFET does not send an error signal before reaching saturation after receiving the turn-on signal. After determining the size of the blanking capacitor, it is necessary to understand the tolerance (maximum value) of the internal reference voltage and the constant current source (minimum value). In addition, it should be considered that the protected SiC MOSFET must be safely turned off within its specified maximum short-circuit time, and the recognition of desaturation detection, internal processing, and turn-off of the SiC MOSFET must be completed within the maximum short-circuit time. Therefore, it is crucial to select the size of the blanking capacitor, and it is difficult to select the size of the blanking capacitor.

[0036] In addition, the measurement of V DS -SAT is to measure the voltage V through a current source and a high-voltage diode DS , and the high-voltage diode has a relatively high junction capacitance, and it takes effect every time the SiC MOSFET is turned on and off. The displacement current flowing through this high-voltage diode is unnecessary and will interfere with other electronic devices.

[0037] Based on this, the present application provides a short-circuit detection circuit for SiC MOSFET, which can perform dynamic short-circuit monitoring on the circuit where the SiC MOSFET is located, and solves the problems of difficult parameter setting and interference with other devices during current short-circuit detection.

[0038] Referring to Figure 1 , the short-circuit detection circuit of the SiC MOSFET in the embodiment of the present application includes an output-side logic control module, an output-stage power amplification circuit, and a short-circuit detection module. The output-side logic control module is used to receive and output the drive pulse signal of the SiCMOSFET, and is also used to output a control signal synchronized with the drive pulse signal, and the control signal is used to control the short-circuit detection module. The output-stage power amplification circuit is electrically connected to the output-side logic control module and is configured to amplify the drive pulse signal and output it to the SiCMOSFET. The short-circuit detection module is electrically connected to the output-side logic control module and the drain D of the SiC MOSFET, and is configured to receive the control signal and obtain a reference voltage signal, and at the same time obtain the drain-source voltage signal of the SiC MOSFET, and output a detection result signal to the output-side logic control module based on the drain-source voltage signal and the reference voltage signal.

[0039] Specifically, the short - circuit detection module can be configured to compare the drain - source voltage signal with the reference voltage signal. When the drain - source voltage signal is greater than the reference voltage signal, the operational amplifier signal flips, and the short - circuit detection module outputs a short - circuit signal to the output - side logic control module. When the drain - source voltage signal is less than or equal to the reference voltage signal, the operational amplifier signal does not flip.

[0040] Reference Figure 2 , the short - circuit detection module 100 may include a comparator, a drain - source voltage signal source circuit, and a reference voltage signal source circuit. The comparator includes a first input terminal, a second input terminal, and an output terminal. The first input terminal is electrically connected to the drain - source voltage signal source circuit for inputting the source - drain voltage signal V of the SiC MOSFET DS , the second input terminal is electrically connected to the reference voltage signal source circuit for inputting the reference voltage signal V ref , and the output terminal is electrically connected to the output - side logic control module for outputting a detection result signal to the output - side logic control module.

[0041] The drain - source voltage signal source circuit includes a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, and an eighth resistor R8. The first end of the fifth resistor R5 is electrically connected to the drain D of the SiC MOSFET, the second end of the fifth resistor R5 is electrically connected to the first end of the sixth resistor R6, and a second capacitor C2 is also electrically connected across the two ends of the fifth resistor R5. The second end of the sixth resistor R6 is electrically connected to the first end of the seventh resistor R7, and a third capacitor C3 is also electrically connected across the two ends of the sixth resistor R6. The second end of the seventh resistor R7 is electrically connected to the first input terminal of the comparator, and a fourth capacitor C4 is also electrically connected across the two ends of the seventh resistor R7. The first end of the eighth resistor R8 is electrically connected to the first input terminal of the comparator, the second end of the eighth resistor R8 is connected to the output - side ground GND, and a fifth capacitor C5 is also electrically connected across the two ends of the eighth resistor R8.

[0042] The reference voltage signal source circuit may include a third MOS transistor M3, a first zener diode T1, a ninth resistor R9, a sixth capacitor C6, and a tenth resistor R10. The gate of the third MOS transistor M3 is electrically connected to the output-side logic control module. The source of the third MOS transistor M3 is connected to the output-side ground GND. The drain of the third MOS transistor M3 is electrically connected to the anode of the first zener diode T1. The on / off state of the third MOS transistor is controlled by the control signal output by the output-side logic control module. The first end of the ninth resistor R9 is electrically connected to the cathode of the first zener diode T1, and the second end of the ninth resistor R9 is electrically connected to the second input terminal of the comparator. The first end of the sixth capacitor C6 is electrically connected to the second input terminal of the comparator, and the second end of the sixth capacitor C6 is connected to the output-side ground GND. The first end of the tenth resistor R10 is electrically connected to the DC positive voltage VCC, and the second end of the tenth resistor R10 is electrically connected to the second input terminal of the comparator.

[0043] In the embodiment of the present application, multiple resistors are connected in series to divide the voltage to obtain the drain-source voltage signal V DS , and the control signal output by the output-side logic control module is used to control the magnitude of the reference voltage signal V ref emitted by the reference voltage signal source circuit. At the same time, the control signal is synchronized with the drive pulse signal. During the turn-on process of the SiC MOSFET, the reference voltage signal V ref exhibits an adjustable characteristic, enabling the short-circuit detection circuit of the embodiment of the present application to achieve dynamic detection.

[0044] Figure 3 For the source-drain voltage signal V DS and the reference voltage signal V ref when the SiC MOSFET turns from off to on and a short circuit occurs in the circuit where it is located. Among them, figure (a) shows that when the SiC MOSFET is off and initially turned on, the third MOS transistor M3 is off, and the reference voltage signal V ref is maintained at the DC positive voltage VCC. In the figure, V T1 represents the forward voltage of the first zener diode T1, and V DS-SAT represents the voltage drop of the SiC MOSFET. When the SiC MOSFET is turned on, the third MOS transistor M3 is turned on, and the reference voltage signal V ref decays from the DC positive voltage VCC to V T1 + V R9 . V R9 is generally very small and can be basically ignored. Figure (b) shows that when the SiC MOSFET is in the on state, if a short circuit occurs in the circuit where the SiC MOSFET is located (a through-state short-circuit fault occurs at point A), the source-drain voltage signal V DS changes from V DS-SATstarts to rise. When the source-drain voltage signal V DS is greater than the reference voltage signal V ref , the operational amplifier signal flips and a short-circuit signal is reported. Figure (c) shows that when the SiC MOSFET is turned on, if a short circuit occurs in the circuit where it is located (a short-circuit fault occurs at point B during the turn-on process), the source-drain voltage signal V DS is greater than the reference voltage signal V ref , the operational amplifier signal flips and a short-circuit signal is reported.

[0045] In other embodiments, on the basis of the short-circuit detection module 100 shown in Figure 2 , reasonable series and parallel adjustments of resistors can be made to meet the requirements for the resistance value in actual use. For example, at least one resistor is connected in series or parallel in the drain-source voltage signal source circuit, or at least one resistor is connected in series or parallel in the reference voltage signal source circuit. That is to say, as long as the dynamic short-circuit detection principle of the embodiments of the present application is adopted, even if simple circuit element adjustments are made on the basis of Figure 2 , they are all within the scope of the examples of the embodiments of the present application.

[0046] Referring to Figure 4 , the short-circuit detection circuit may further include an auxiliary detection module. The auxiliary detection module is located between the Kelvin pin K and the source pin of the SiC MOSFET and is used to detect the current change rate (di / dt) of the SiC MOSFET. Existing drive circuits do not detect the current change rate of the SiC MOSFET. However, the SiC MOSFET has a large di / dt under normal operation, short-circuit faults, overcurrent faults, etc. Therefore, in the embodiments of the present application, a device with a Kelvin pin package form is used to measure the di / dt parameter from the parasitic reactance between the Kelvin pin and the source pin, which can be used as an auxiliary criterion for short-circuit or overcurrent faults.

[0047] In some embodiments, the auxiliary detection module 200 includes a second diode Z2, an eleventh resistor R11, a twelfth resistor R12, a seventh capacitor C7, and a transformer. The anode of the second diode Z2 and the Kelvin pin are both connected to the output-side ground GND. The cathode of the second diode Z2 is electrically connected to the first end of the eleventh resistor R11. The second end of the eleventh resistor R11 is electrically connected to the source S of the SiC MOSFET. The first end of the twelfth resistor R12 is electrically connected to the cathode of the second diode Z2. The second end of the twelfth resistor R12 is electrically connected to the first end of the seventh capacitor C7. The second end of the seventh capacitor C7 is electrically connected to the source S of the SiC MOSFET. The primary side of the transformer is electrically connected to both ends of the seventh capacitor C7. One end of the secondary side of the transformer is electrically connected to the output-side logic control module, and the other end is connected to the output-side ground GND.

[0048] The output - stage power - amplification circuit may be a totem - pole structure built with a power operational amplifier or discrete components for amplifying the power of the driving signal. As an example, the output - stage power - amplification circuit may be a push - pull driving circuit including PMOS transistors and NMOS transistors, or a push - pull driving circuit including NPN and PNP bipolar transistors.

[0049] Reference Figure 5 Referring to, the output - stage power - amplification circuit 300 in the embodiment of the present application is, for example, a push - pull driving circuit including PMOS transistors and NMOS transistors. Specifically, the output - stage power - amplification circuit 300 may include an amplifier, a PMOS transistor P, an NMOS transistor N, and a third resistor R3 serving as an output resistor, and may also include a turn - off resistor R1. The input end of the amplifier is electrically connected to the output - side logic control module, and the amplifier is also electrically connected to a DC positive voltage VCC, a DC negative voltage VEE, and an output - side ground GND. The source of the PMOS transistor P is electrically connected to the DC voltage VCC, the gate of the PMOS transistor P is electrically connected to the output end of the amplifier, and the drain of the PMOS transistor P is electrically connected to the gate of the SiC MOSFET through the third resistor R3. The source of the NMOS transistor is electrically connected to the DC negative voltage VEE, the gate of the NMOS transistor is electrically connected to the output end of the amplifier, and the NMOS transistor is electrically connected to the gate of the SiC MOSFET through the first resistor R1.

[0050] The circuit structure of the output - side logic control module only needs to be able to receive the driving pulse signal of the SiC MOSFET and output it to the output - stage power - amplification circuit, and can output a control signal synchronized with the driving pulse signal to the short - circuit detection module. Therefore, the embodiment of the present application does not limit the specific circuit structure of the output - side logic control module, and any circuit structure that can implement the above functions can be used for the output - side logic control module in the embodiment of the present application.

[0051] Reference Figure 6 Referring to, in some embodiments, the short - circuit detection circuit further includes an input - side logic control module for receiving the driving pulse signal of the SiC MOSFET and outputting it to the output - side logic control module, and the output - side logic control module also feeds back the detection result signal to the input - side logic control module. The specific structure of the input - side logic control module is not limited, and any circuit structure that can implement the above functions can be used.

[0052] A second encoding and decoding module may also be electrically connected between the input-side logic control module and the output-side logic control module. The second encoding and decoding module includes: a feedback encoding module electrically connected to the output-side logic control module; and a feedback decoding module that is signal-isolated from the feedback encoding module and electrically connected to the input-side logic control module.

[0053] An embodiment of the present application also provides a short-circuit detection method for a SiC MOSFET, which can be implemented by the above short-circuit detection circuit or by other transformed circuits. The short-circuit detection method includes: the output-side logic control module receives the drive pulse signal of the SiC MOSFET and outputs it, and is also used to output a control signal synchronized with the drive pulse signal; the output-stage power amplification circuit amplifies the drive pulse signal and outputs it to the SiC MOSFET; the short-circuit detection module receives the control signal and obtains a reference voltage signal, and at the same time obtains the drain-source voltage signal of the SiC MOSFET, and outputs a detection result signal to the output-side logic control module based on the drain-source voltage signal and the reference voltage signal.

[0054] In some embodiments, the method of outputting a detection result signal to the output-side logic control module based on the drain-source voltage signal and the reference voltage signal includes: comparing the drain-source voltage signal with the reference voltage signal. When the drain-source voltage signal is greater than the reference voltage signal, the operational amplifier signal flips, and the short-circuit detection module outputs a short-circuit signal to the output-side logic control module. When the drain-source voltage signal is less than the reference voltage signal, the operational amplifier signal does not flip.

[0055] In summary, after reading the content of the present application, those skilled in the art can understand that the foregoing application content may be presented only by way of example and may not be restrictive. Although not explicitly stated here, those skilled in the art can understand that the present application is intended to encompass various reasonable changes, improvements, and modifications to the embodiments. These changes, improvements, and modifications are within the spirit and scope of the exemplary embodiments of the present application.

[0056] It should also be understood that although the terms first, second, third, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. Therefore, without departing from the teachings of the present application, a first element in some embodiments may be referred to as a second element in other embodiments. The same reference numerals or the same reference markers represent the same elements throughout the specification.

Claims

1. A short - circuit detection circuit for a SiC MOSFET, characterized in that, Including: An output - side logic control module, which is used to receive and output the driving pulse signal of the SiC MOSFET, and is also used to output a control signal synchronized with the driving pulse signal; An output - stage power amplification circuit, which is electrically connected to the output - side logic control module and is configured to amplify the driving pulse signal and output it to the SiC MOSFET; A short - circuit detection module, which is electrically connected to the output - side logic control module and the drain of the SiC MOSFET, and is configured to receive the control signal and obtain a reference voltage signal, and at the same time obtain the drain - source voltage signal of the SiC MOSFET, and output a detection result signal to the output - side logic control module based on the drain - source voltage signal and the reference voltage signal. The short - circuit detection module is configured to compare the drain - source voltage signal with the reference voltage signal. When the drain - source voltage signal is greater than the reference voltage signal, the operational - amplifier signal flips, and the short - circuit detection module outputs a short - circuit signal to the output - side logic control module.

2. The short-circuit detection circuit of the SiC MOSFET according to claim 1, characterized in that, The short - circuit detection module is further configured to compare the drain - source voltage signal with the reference voltage signal. When the drain - source voltage signal is less than or equal to the reference voltage signal, the operational - amplifier signal does not flip.

3. The short-circuit detection circuit of the SiC MOSFET according to claim 2, characterized in that, The short - circuit detection module includes: A comparator, including a first input terminal, a second input terminal and an output terminal, where the output terminal is electrically connected to the output - side logic control module; A drain - source voltage signal source circuit, electrically connected to the first input terminal; A reference voltage signal source circuit, electrically connected to the second input terminal.

4. The short - circuit detection circuit of the SiC MOSFET according to claim 3, wherein, The drain - source voltage signal source circuit includes: A fifth resistor, the first end of the fifth resistor is electrically connected to the drain of the SiC MOSFET, and a second capacitor is also electrically connected across the two ends of the fifth resistor; A sixth resistor, the first end of the sixth resistor is electrically connected to the second end of the fifth resistor, and a third capacitor is also electrically connected across the two ends of the sixth resistor; A seventh resistor, the first end of the seventh resistor is electrically connected to the second end of the sixth resistor, the second end is electrically connected to the first input terminal, and a fourth capacitor is also electrically connected across the two ends of the seventh resistor; An eighth resistor, the first end of the eighth resistor is electrically connected to the first input terminal, and the second end of the eighth resistor is connected to the output - side ground, and a fifth capacitor is also electrically connected across the two ends of the eighth resistor.

5. The short-circuit detection circuit of the SiC MOSFET according to claim 3, characterized in that, The reference voltage signal source circuit includes: A third MOS transistor, the gate of the third MOS transistor is electrically connected to the output - side logic control module, the source is connected to the output - side ground, and the third MOS transistor is controlled by the control signal; A first zener diode, the anode of the first zener diode is electrically connected to the drain of the third MOS transistor; A ninth resistor, the first end of the ninth resistor is electrically connected to the cathode of the first zener diode, and the second end is electrically connected to the second input terminal; A sixth capacitor, the first end of the sixth capacitor is electrically connected to the second input terminal, and the second end is connected to the output - side ground; A tenth resistor, the first end of the tenth resistor is electrically connected to the DC positive voltage, and the second end is electrically connected to the second input terminal.

6. The short-circuit detection circuit of the SiC MOSFET according to claim 1, wherein The short-circuit detection circuit further includes: an auxiliary detection module located between the Kelvin pin and the source pin of the SiC MOSFET for detecting the current change rate of the SiC MOSFET.

7. The short-circuit detection circuit of the SiC MOSFET according to claim 6, characterized in that, The auxiliary detection module includes: A second diode, the anode of which is connected to the output-side ground; An eleventh resistor, the first end of which is electrically connected to the cathode of the second diode, and the second end of which is electrically connected to the source of the SiC MOSFET; A twelfth resistor, the first end of which is electrically connected to the cathode of the second diode; A seventh capacitor, the first end of which is electrically connected to the second end of the twelfth resistor, and the second end of which is electrically connected to the source of the SiC MOSFET; A transformer, the primary side of which is electrically connected to both ends of the seventh capacitor, and one end of the secondary side is electrically connected to the output-side logic control module, and the other end is connected to the output-side ground.

8. The short-circuit detection circuit of the SiC MOSFET according to claim 1, characterized in that, The output-stage power amplifier circuit includes a push-pull drive circuit composed of a PMOS transistor and an NMOS transistor, or includes a push-pull drive circuit composed of an NPN transistor and a PNP transistor.

9. The short-circuit detection circuit of the SiC MOSFET according to claim 8, wherein, The output-stage power amplifier circuit includes: An amplifier, the input end of which is electrically connected to the output-side logic control module, and the amplifier is also electrically connected to a DC positive voltage, a DC negative voltage, and the output-side ground; A PMOS transistor, the source of which is electrically connected to the DC positive voltage, the gate of which is electrically connected to the output end of the amplifier, and the drain of which is electrically connected to the gate of the SiC MOSFET through a third resistor; An NMOS transistor, the source of which is electrically connected to the DC negative voltage, the gate of which is electrically connected to the output end of the amplifier, and the drain of which is electrically connected to the gate of the SiC MOSFET through a first resistor.

10. The short - circuit detection circuit of the SiC MOSFET according to claim 1, characterized in that, The short-circuit detection circuit further includes an input-side logic control module for receiving the drive pulse signal of the SiC MOSFET and outputting it to the output-side logic control module, and the output-side logic control module also feeds back the detection result signal to the input-side logic control module.

11. The short - circuit detection circuit of the SiC MOSFET according to claim 10, characterized in that, There is also a second encoding and decoding module electrically connected between the input-side logic control module and the output-side logic control module. The second encoding and decoding module includes: A feedback encoding module electrically connected to the output-side logic control module; A feedback decoding module, which is signal-isolated from the feedback encoding module and is electrically connected to the input-side logic control module.

12. A short - circuit detection method for a SiC MOSFET, characterized in that, Includes: The output-side logic control module receives the drive pulse signal of the SiC MOSFET and outputs it, and is also used to output a control signal synchronized with the drive pulse signal; The output-stage power amplifier circuit amplifies the drive pulse signal and outputs it to the SiC MOSFET; The short-circuit detection module receives the control signal and obtains a reference voltage signal, and at the same time obtains the drain-source voltage signal of the SiC MOSFET, and outputs a detection result signal to the output-side logic control module based on the drain-source voltage signal and the reference voltage signal. The method for outputting the detection result signal to the output-side logic control module based on the drain-source voltage signal and the reference voltage signal includes: comparing the drain-source voltage signal with the reference voltage signal. When the drain-source voltage signal is greater than the reference voltage signal, the operational amplifier signal flips, and the short-circuit detection module outputs a short-circuit signal to the output-side logic control module.

13. The short-circuit detection method of the SiC MOSFET according to claim 12, wherein when the drain-source voltage signal is less than the reference voltage signal, the operational amplifier signal does not flip.

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