System for suppressing positive crosstalk and negative crosstalk of silicon carbide MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor)

Abstract

The embodiment of the invention provides a system for inhibiting positive crosstalk and negative crosstalk of a silicon carbide MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor), and belongs to the technical field of power electronics. The system comprises a negative crosstalk suppression circuit which is arranged on a connection path between a grid electrode of a silicon carbide MOSFET and a source electrode of the silicon carbide MOSFET, and the negative crosstalk suppression circuit comprises a first one-way conduction element and a PNP triode. According to the invention, the applicability of the negative crosstalk suppression system can be improved.

Description

Technical Field

[0001] This invention relates to the field of power electronics technology, and more specifically to a system for suppressing positive and negative crosstalk in silicon carbide MOSFETs. Background Technology

[0002] When a traditional MOSFET switches with extremely fast rise or fall edges, high-amplitude pulses are coupled into the drive circuit through the parasitic capacitance of the MOSFET, causing positive or negative crosstalk in the gate voltage. Positive crosstalk can lead to false turn-on of the power device, thus burning it out. Negative crosstalk can damage the gate oxide layer of the traditional MOSFET, reducing its lifespan.

[0003] Existing methods suppress positive and negative crosstalk by adding a Miller clamp circuit to shunt the positive and negative crosstalk currents of a traditional MOSFET. However, the self-biased PNP transistor and p-channel MOSFET in the Miller clamp circuit can only unidirectionally block voltage. Therefore, existing Miller clamp circuits are not suitable for bipolar drive with positive voltage turn-on and negative voltage turn-off. Silicon carbide MOSFETs, due to their small die area, have a much larger internal gate resistance than traditional MOSFETs. To avoid false turn-on due to potential positive crosstalk causing the actual gate voltage inside the silicon carbide MOSFET to exceed 0V, silicon carbide MOSFETs require bipolar drive with positive voltage turn-on and negative voltage turn-off. Therefore, existing techniques using Miller clamp circuits are not suitable for bipolar drive with positive voltage turn-on and negative voltage turn-off, resulting in limited applicability for suppressing negative crosstalk. Summary of the Invention

[0004] The purpose of this application is to provide a system for suppressing positive and negative crosstalk in silicon carbide MOSFETs, thereby solving the problem of limited applicability of the prior art in suppressing negative crosstalk.

[0005] To achieve the above objectives, this application provides a system for suppressing positive and negative crosstalk in silicon carbide MOSFETs, the system comprising: A negative crosstalk suppression circuit is disposed on the connection path between the gate and the source of a silicon carbide MOSFET. The negative crosstalk suppression circuit includes a first unidirectional conducting element and a PNP transistor.

[0006] In this embodiment, the first unidirectional conducting element includes a first diode, the cathode of which is connected to the gate of a silicon carbide MOSFET, and the anode of which is connected to the collector of a PNP transistor.

[0007] In this embodiment of the application, the first unidirectional conducting element includes a first NPN transistor, the collector of the first NPN transistor is connected to the base of the first NPN transistor, the collector of the first NPN transistor is connected to the collector of the PNP transistor, and the emitter of the first NPN transistor is connected to the gate of the silicon carbide MOSFET.

[0008] In this embodiment, the emitter of the PNP transistor is connected to the source of the silicon carbide MOSFET.

[0009] In this embodiment of the application, the system includes a first resistor, one end of which is connected to the emitter of a PNP transistor, and the other end of which is connected to the base of the PNP transistor.

[0010] In this embodiment, the gate of the silicon carbide MOSFET is connected to the power supply terminal of the bipolar drive module, and the source of the silicon carbide MOSFET is connected to the input terminal of the bipolar drive module. The system includes: A forward crosstalk suppression circuit is disposed on the connection path between the gate of the silicon carbide MOSFET and the power supply terminal of the bipolar drive module. The forward crosstalk suppression circuit includes a second unidirectional conduction element.

[0011] In this embodiment, the second unidirectional conducting element includes a second diode, the anode of which is connected to the gate of a silicon carbide MOSFET, and the cathode of which is connected to the power supply terminal of a bipolar drive module.

[0012] In this embodiment of the application, the second unidirectional conducting element includes a second NPN transistor, the collector of the second NPN transistor is connected to the base of the first NPN transistor, the collector of the second NPN transistor is connected to the gate of the silicon carbide MOSFET, and the emitter of the second NPN transistor is connected to the power supply terminal of the bipolar driving module.

[0013] In this embodiment of the application, the system includes a second resistor, one end of which is connected to the anode of the second diode, and the other end of which is connected to the cathode of the second diode.

[0014] In this embodiment, the grounding terminal of the bipolar drive module is grounded.

[0015] The above technical solution, by placing a first unidirectional conducting element and a PNP transistor in the connection path between the gate and source of the silicon carbide MOSFET, can increase the voltage between the gate and source of the silicon carbide MOSFET when negative crosstalk occurs, thereby improving the lifespan of the silicon carbide MOSFET. The method of this application for increasing the voltage between the gate and source of the silicon carbide MOSFET and improving its lifespan is applicable not only to silicon carbide MOSFETs but also to conventional MOSFETs, thus improving the applicability of the negative crosstalk suppression system.

[0016] Other features and advantages of the embodiments of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0017] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings: Figure 1 This illustration schematically depicts a system for suppressing positive and negative crosstalk in a silicon carbide MOSFET according to an embodiment of this application. Figure 1 ; Figure 2 This is an illustrative diagram of a system for suppressing positive and negative crosstalk in a silicon carbide MOSFET according to an embodiment of this application. Figure 2 .

[0018] Explanation of reference numerals in the attached figures Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for illustration and explanation of the embodiments of this application and are not intended to limit the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0020] It should be noted that if the embodiments of this application involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0021] Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0022] Figure 1 This diagram schematically illustrates a system for suppressing positive and negative crosstalk in a silicon carbide MOSFET according to an embodiment of this application. Figure 1 As shown in the embodiments of this application, a system for suppressing positive and negative crosstalk in silicon carbide MOSFETs is provided. This system may include: A negative crosstalk suppression circuit is disposed on the connection path between the gate and the source of a silicon carbide MOSFET. The negative crosstalk suppression circuit includes a first unidirectional conducting element and a PNP transistor.

[0023] It can be understood that the first unidirectional conducting element is a conducting element that can only conduct circuits in one direction.

[0024] Specifically, the first unidirectional conducting element and the PNP transistor 101 of this application are disposed on the connection path between the gate and the source of the silicon carbide MOSFET.

[0025] The above technical solution, by placing the first unidirectional conducting element and the PNP transistor 101 in the connection path between the gate and source of the silicon carbide MOSFET, can increase the voltage between the gate and source of the silicon carbide MOSFET when negative crosstalk occurs, thereby improving the lifespan of the silicon carbide MOSFET. The method of this application for increasing the voltage between the gate and source of the silicon carbide MOSFET and improving its lifespan is applicable not only to silicon carbide MOSFETs but also to conventional MOSFETs, thus improving the applicability of the negative crosstalk suppression system.

[0026] In one embodiment, the first unidirectional conducting element includes a first diode 102, the cathode of the first diode 102 being connected to the gate of a silicon carbide MOSFET, and the anode of the first diode 102 being connected to the collector of a PNP transistor 101.

[0027] It can be understood that the first diode 102 is a diode connected to the gate of the silicon carbide MOSFET and the collector of the PNP transistor 101.

[0028] Specifically, the first diode 102 is disposed in the connection path between the gate of the silicon carbide MOSFET and the collector of the PNP transistor, and the first diode 102 is connected to the gate of the silicon carbide MOSFET, while the anode of the first diode 102 is connected to the collector of the PNP transistor 101. Therefore, this application can achieve unidirectional current conduction by using the first diode 102, allowing the gate current of forward crosstalk to flow to the forward crosstalk suppression circuit, thereby achieving forward crosstalk suppression.

[0029] In one embodiment, the first unidirectional conducting element includes a first NPN transistor 103, the collector of the first NPN transistor 103 is connected to the base of the first NPN transistor 103, the collector of the first NPN transistor 103 is connected to the collector of the PNP transistor 101, and the emitter of the first NPN transistor 103 is connected to the gate of the silicon carbide MOSFET.

[0030] It can be understood that the first NPN transistor 103 is a transistor in which the emitter of the first NPN transistor 103 is connected to the gate of the silicon carbide MOSFET, and the collector of the first NPN transistor 103 is connected to the collector of the PNP transistor 101.

[0031] Specifically, in this application, the collector of the first NPN transistor 103 is connected to the base of the first NPN transistor 103, the collector of the first NPN transistor 103 is connected to the collector of the PNP transistor 101, and the emitter of the first NPN transistor 103 is connected to the gate of the silicon carbide MOSFET. Therefore, this application can achieve unidirectional current conduction by configuring the first NPN transistor 103, causing the gate current of forward crosstalk to flow to the forward crosstalk suppression circuit, thereby achieving forward crosstalk suppression.

[0032] In one embodiment, the emitter of the PNP transistor 101 is connected to the source of the silicon carbide MOSFET.

[0033] Specifically, connecting the emitter of the PNP transistor 101 to the source of the silicon carbide MOSFET can connect the negative crosstalk suppression circuit to the source of the silicon carbide MOSFET, thereby achieving the function of negative crosstalk suppression.

[0034] In one embodiment, the system includes a first resistor 104, one end of which is connected to the emitter of a PNP transistor 101, and the other end of which is connected to the base of the PNP transistor 101.

[0035] It can be understood that the first resistor 104 is a resistor connected to the emitter and base of the PNP transistor 101.

[0036] Specifically, one end of the first resistor 104 in this application is connected to the emitter of the PNP transistor 101, and the other end of the first resistor 104 is connected to the base of the PNP transistor 101, which can provide a conduction voltage for the PNP transistor 101 to ensure the normal operation of the negative crosstalk suppression circuit.

[0037] In one embodiment, the gate of the silicon carbide MOSFET is connected to the power supply terminal of the bipolar drive module, and the source of the silicon carbide MOSFET is connected to the input terminal of the bipolar drive module. The system includes: A forward crosstalk suppression circuit is disposed on the connection path between the gate of the silicon carbide MOSFET and the power supply terminal of the bipolar drive module. The forward crosstalk suppression circuit includes a second unidirectional conduction element.

[0038] It can be understood that the second unidirectional conducting element is a conducting element that can only conduct circuits in one direction.

[0039] Specifically, the second unidirectional conducting element is disposed on the connection path between the gate of the silicon carbide MOSFET and the power supply terminal of the bipolar drive module. It can only conduct the circuit in one direction and short-circuit the first resistor. In order to reduce the voltage between the gate and source of the silicon carbide MOSFET when positive crosstalk occurs, it can prevent the voltage between the gate and source of the silicon carbide MOSFET from being too large to reach the turn-on voltage of the silicon carbide MOSFET and causing false turn-on.

[0040] In one embodiment, the second unidirectional conducting element includes a second diode 105, the anode of which is connected to the gate of a silicon carbide MOSFET, and the cathode of which is connected to the power supply terminal of a bipolar drive module.

[0041] It can be understood that the second diode 105 is a diode located at the gate of the silicon carbide MOSFET and at the power output terminal of the bipolar drive module.

[0042] Specifically, the second diode 105 conducts the current flowing from the gate of the silicon carbide MOSFET to the power output terminal of the bipolar drive module, while short-circuiting the first resistor 104. When forward crosstalk occurs, it reduces the voltage between the gate and source of the silicon carbide MOSFET, preventing the voltage between the gate and source of the silicon carbide MOSFET from becoming too large and reaching the turn-on voltage of the silicon carbide MOSFET, thus preventing false turn-on.

[0043] In one embodiment, the second unidirectional conducting element includes a second NPN transistor 106, the collector of the second NPN transistor 106 is connected to the base of the first NPN transistor 103, the collector of the second NPN transistor 106 is connected to the gate of the silicon carbide MOSFET, and the emitter of the second NPN transistor 106 is connected to the power supply terminal of the bipolar drive module.

[0044] It can be understood that the second NPN transistor 106 is a diode whose collector is connected to the gate of the silicon carbide MOSFET and whose emitter is connected to the power supply terminal of the bipolar drive module.

[0045] Specifically, the collector of the second NPN transistor 106 is connected to the base of the first NPN transistor 103, the collector of the second NPN transistor 106 is connected to the gate of the silicon carbide MOSFET, and the emitter of the second NPN transistor 106 is connected to the power supply terminal of the bipolar drive module. The second NPN transistor 106 can conduct the current flowing from the gate of the silicon carbide MOSFET to the power output terminal of the bipolar drive module, while short-circuiting the first resistor 104. When forward crosstalk occurs, it reduces the voltage between the gate and source of the silicon carbide MOSFET, preventing the voltage between the gate and source of the silicon carbide MOSFET from becoming too high and reaching the turn-on voltage of the silicon carbide MOSFET, thus preventing false turn-on.

[0046] In one embodiment, the system includes a second resistor 107, one end of which is connected to the anode of a second diode 105, and the other end of which is connected to the cathode of the second diode 105.

[0047] It can be understood that the second resistor 107 is a resistor connected to the anode and cathode of the second diode 105.

[0048] Specifically, connecting one end of the second resistor 107 to the anode of the second diode 105 and connecting the other end of the second resistor 107 to the cathode of the second diode 105 can enable the connection of one end of the second resistor 107 to the gate of the silicon carbide MOSFET and the connection of the other end of the second resistor 107 to the cathode of the second diode 105 to the power supply terminal of the bipolar drive module, thereby protecting the circuit.

[0049] In one embodiment, the grounding terminal of the bipolar drive module is grounded.

[0050] Specifically, grounding the ground terminal of the bipolar drive module facilitates the output of a stable voltage difference to drive the silicon carbide MOSFET.

[0051] With the increasing demands for high efficiency, high power density, and high-temperature operation in power electronic systems, silicon carbide (SiC)-based wide-bandgap semiconductor devices have become the preferred alternative to traditional silicon devices due to their advantages such as wide bandgap, high thermal conductivity, and strong breakdown field. In particular, silicon carbide MOSFETs exhibit lower conduction and switching losses under high voltage (≥ 600 V) and high frequency (≥ 100 kHz) conditions, significantly improving system efficiency and reducing heat dissipation requirements. Therefore, they are rapidly being adopted in high-power inverters, electric vehicle traction, and new energy grid connection applications.

[0052] In a half-bridge topology, when a silicon carbide MOSFET switches with extremely fast rise / fall edges, high-amplitude dv / dt pulses are coupled into the drive circuit through the MOSFET's parasitic capacitance, causing positive or negative crosstalk in the gate voltage. Positive crosstalk can lead to false turn-on of the power device, thus burning it out; negative crosstalk can damage the gate oxide layer of the silicon carbide MOSFET, reducing its lifespan.

[0053] Active crosstalk suppression methods increase cost and design complexity by adding extra logic control circuits and auxiliary semiconductor devices to stabilize the gate voltage of the driving circuit. They also pose challenges to the stability of the circuit under long-term operation. Therefore, they have not been widely adopted in practical applications.

[0054] Passive crosstalk suppression methods are more common in practical applications due to their simple structure and control. The basic approach involves adding a Miller clamp circuit to shunt the gate current induced by crosstalk, thereby stabilizing the gate voltage. Typical Miller clamp circuits use a self-biased PNP transistor 101 or a p-channel MOSFET circuit to shunt the gate current induced by crosstalk. However, since the self-biased PNP transistor 101 and p-channel MOSFET can only unidirectionally block voltage, they cannot be combined for bipolar drive using positive voltage turn-on and negative voltage turn-off. Silicon carbide MOSFETs, due to their small die area, have a much larger internal gate resistance than silicon devices. For unipolar drive with 0V turn-off, even if the voltage at the gate pin of the silicon carbide MOSFET is clamped to 0V by the Miller clamp circuit, the actual gate voltage inside the MOSFET may still be greater than 0V under forward crosstalk, leading to false turn-on. Therefore, the bipolar drive with negative voltage turn-off can clamp the voltage at the gate pin to a negative voltage, which can better suppress the positive crosstalk of the silicon carbide MOSFET. However, on the other hand, the bipolar drive also needs to deal with the problem of negative crosstalk and bidirectional voltage blocking of the Miller clamp circuit. This patent optimizes the Miller clamp low impedance path design method and combines it with the bipolar drive module to form a bipolar drive circuit for silicon carbide MOSFETs with positive / negative crosstalk suppression.

[0055] A specific embodiment of this application provides a system for suppressing positive and negative crosstalk in silicon carbide MOSFETs, referring to... Figure 1 and Figure 2 As shown, the specific content can be as follows: A negative crosstalk suppression circuit is disposed on the connection path between the gate and source of a silicon carbide MOSFET. The negative crosstalk suppression circuit includes a first unidirectional conducting element and a PNP transistor. The first unidirectional conducting element includes a first diode 102, the cathode of which is connected to the gate of the silicon carbide MOSFET, and the anode of which is connected to the collector of the PNP transistor 101. The first unidirectional conducting element also includes a first NPN transistor 103, the collector of which is connected to the base of which is connected to the base of which is connected to the collector ... The system includes a first resistor 104, one end of which is connected to the emitter of a PNP transistor 101, and the other end of which is connected to the base of the PNP transistor 101. The gate of a silicon carbide MOSFET is connected to the power supply terminal of the bipolar drive module, and the source of the silicon carbide MOSFET is connected to the input terminal of the bipolar drive module. The system includes a forward crosstalk suppression circuit disposed in the connection path between the gate of the silicon carbide MOSFET and the power supply terminal of the bipolar drive module. The forward crosstalk suppression circuit includes a second unidirectional conducting element. The second unidirectional conducting element includes a second diode 105, the anode of which is connected to the gate of the silicon carbide MOSFET, and the cathode of which is connected to the power supply terminal of the bipolar drive module. The second unidirectional conducting element includes a second NPN transistor 106. The collector of the second NPN transistor 106 is connected to the base of the first NPN transistor 103, and the collector of the second NPN transistor 106 is connected to the gate of the silicon carbide MOSFET. The emitter of the second NPN transistor 106 is connected to the power supply terminal of the bipolar drive module. The system includes a second resistor 107. One end of the second resistor 107 is connected to the anode of the second diode 105, and the other end of the second resistor 107 is connected to the cathode of the second diode 105. The ground terminal of the bipolar drive module is grounded.

[0056] The system architecture consists of a bipolar driver integrated chip, a positive crosstalk suppression circuit, and a negative crosstalk suppression circuit. The positive crosstalk suppression circuit is located between the MOSFET gate connection terminal and the bipolar driver module output terminal Vout. A second diode 105 provides a bypass shunt to the gate current that induces positive crosstalk, suppressing excessively high gate voltage. The negative crosstalk suppression circuit is a series circuit of a first diode 102 between the MOSFET gate and source terminals. It shunts the source current that induces negative crosstalk, suppressing excessively low gate voltage.

[0057] The bipolar drive module provides a positive voltage when the MOSFET is turned on and a negative voltage when the MOSFET is turned off.

[0058] The forward crosstalk suppression circuit is located between the output terminal Vout of the bipolar drive module and the gate connection terminal. Its structure consists of a second resistor 107 connected in parallel with a second diode 105. The cathode of the second diode 105 is connected to Vout, and the anode is connected to the gate connection terminal.

[0059] In the negative crosstalk suppression circuit, the emitter and source terminals of the PNP transistor 101 are connected, the cathode and gate terminals of the first diode 102 are connected, the base of the PNP transistor 101 is connected to the ground terminal GND of the bipolar drive module, and the first resistor 104 is located between the base and emitter of the PNP transistor 101.

[0060] Figure 1 This describes the circuit structure for the implementation method. The output voltage Vout of the bipolar drive module is selectable within the range of +15V to +20V and -3V to -5V, serving as the turn-on and turn-off drive voltages, respectively. Here, we take a +20V turn-on drive voltage and a -5V turn-off drive voltage as examples.

[0061] The forward crosstalk suppression circuit consists of a second diode 105 and a second resistor 107 connected in parallel, located between the output terminal and the gate connection section of the bipolar drive module. The cathode of the second diode 105 is connected to the output terminal of the bipolar drive module, and the anode is connected to the gate connection terminal.

[0062] The negative crosstalk suppression circuit consists of a first diode 102, a PNP transistor 101, and a first resistor 104. The first diode 102 is connected in series with the PNP transistor 101. The cathode of the first diode 102 is connected to its gate. The emitter of the PNP transistor 101 is connected to its source. The base of the PNP transistor 101 is connected to the bipolar drive module GND.

[0063] When the MOSFET is turned on, the peak gate current is determined by the second resistor 107, the first resistor 104, and the gate resistance Rint of the MOSFET. The calculation formula is as follows:

[0064] in This represents the peak gate current during turn-on. The gate drive voltage for turning on the silicon carbide MOSFET is +20V in this embodiment; The gate drive voltage is the one that is turned off; in this embodiment, its value is -5V. This is the resistance value of the second resistor, 107. The resistance value of the first resistor is 104. Rint is the resistance value of the MOSFET gate internal resistance.

[0065] Because of the reverse bias of the second diode 105, when the output voltage Vout is positive, the possibility of short circuit between the gate connection terminal and the source connection segment caused by the conduction of the collector-base PN junction of the PNP transistor 101 is eliminated.

[0066] When the MOSFET is turned off, the first resistor 104, the second diode 105, and the MOSFET gate resistance Rint determine the peak gate current during turn-off. The calculation formula is as follows:

[0067] in This represents the peak gate current during turn-on. This is the forward voltage of the second diode 105.

[0068] The selection of the second diode 105 needs to meet the following requirements:

[0069] in This is the rated on-state current of the second diode 105.

[0070] The principle of suppressing positive and negative crosstalk is as follows: Figure 2 As shown.

[0071] When forward crosstalk occurs, i.e., the drain-source voltage of the off silicon carbide MOSFET begins to rise, the gate current inducing forward crosstalk can be estimated as:

[0072] in, To induce gate current for positive crosstalk, This refers to the gate-drain capacitance of the MOSFET. This is the drain-source voltage. The slope of the desired drain-source voltage change.

[0073] The current flows into the drive circuit from the gate connection and exits the drive circuit from the source connection. Because the second diode 105 and the second resistor 107 are connected in parallel, current is shunted. This reduces the amount of resistance caused by the second resistor 107 and... The coupled gate voltage, the actual gate voltage of the silicon carbide MOSFET is determined by... Reduced to:

[0074] in This is the actual gate voltage under positive crosstalk. This is the internal gate resistance of the MOSFET.

[0075] The rated on-current of the second diode 105 must also meet the following requirements:

[0076] When negative crosstalk occurs, i.e., the drain-source voltage of the off silicon carbide MOSFET begins to decrease, the gate current inducing negative crosstalk can be estimated as:

[0077] in, The gate current is used to induce negative crosstalk.

[0078] The current flows into the drive circuit from the source connection and out of the drive circuit from the gate connection. When it flows from the source connection through the first resistor 104, it generates the base-emitter voltage of the PNP transistor 101. When the emitter-base voltage of PNP transistor 101 is greater than the PN junction turn-on voltage of PNP transistor 101, PNP transistor 101 starts to conduct. The actual gate voltage of the MOSFET flows out from the gate output terminal through the PNP transistor 101 and the first diode 102. Upgraded to:

[0079] in, This is the PN junction turn-on voltage of the emitter-base PNP transistor 101. This is the forward conduction voltage of the first diode 102.

[0080] The selection of the first resistor 104 needs to meet the following requirements:

[0081] The selection of PNP transistor 101 and first diode 102 needs to meet the following requirements.

[0082] when hour,

[0083] in, This is the emitter voltage of the PNP transistor 101. This is the rated collector current of the PNP transistor 101. This is the rated on-state current of the first diode 102.

[0084] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0085] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A system for suppressing positive and negative crosstalk in silicon carbide MOSFETs, characterized in that, The system includes: A negative crosstalk suppression circuit is disposed on the connection path between the gate and the source of the silicon carbide MOSFET. The negative crosstalk suppression circuit includes a first unidirectional conducting element and a PNP transistor.

2. The system according to claim 1, characterized in that, The first unidirectional conducting element includes a first diode, the cathode of which is connected to the gate of a silicon carbide MOSFET, and the anode of which is connected to the collector of the PNP transistor.

3. The system according to claim 1, characterized in that, The first unidirectional conducting element includes a first NPN transistor, the collector of the first NPN transistor is connected to the base of the first NPN transistor, the collector of the first NPN transistor is connected to the collector of the PNP transistor, and the emitter of the first NPN transistor is connected to the gate of the silicon carbide MOSFET.

4. The system according to claim 1, characterized in that, The emitter of the PNP transistor is connected to the source of the silicon carbide MOSFET.

5. The system according to claim 1, characterized in that, The system includes a first resistor, one end of which is connected to the emitter of the PNP transistor, and the other end of which is connected to the base of the PNP transistor.

6. The system according to claim 1, characterized in that, The gate of the silicon carbide MOSFET is connected to the power supply terminal of the bipolar drive module, and the source of the silicon carbide MOSFET is connected to the input terminal of the bipolar drive module. The system includes: A forward crosstalk suppression circuit is disposed on the connection path between the gate of the silicon carbide MOSFET and the power supply terminal of the bipolar drive module, and the forward crosstalk suppression circuit includes a second unidirectional conduction element.

7. The system according to claim 6, characterized in that, The second unidirectional conducting element includes a second diode, the anode of which is connected to the gate of the silicon carbide MOSFET, and the cathode of which is connected to the power supply terminal of the bipolar drive module.

8. The system according to claim 6, characterized in that, The second unidirectional conducting element includes a second NPN transistor, the collector of the second NPN transistor is connected to the base of the first NPN transistor, the collector of the second NPN transistor is connected to the gate of the silicon carbide MOSFET, and the emitter of the second NPN transistor is connected to the power supply terminal of the bipolar drive module.

9. The system according to claim 6, characterized in that, The system includes a second resistor, one end of which is connected to the anode of the second diode, and the other end of which is connected to the cathode of the second diode.

10. The system according to claim 6, characterized in that, The grounding terminal of the bipolar drive module is grounded.

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