MOS transistor control method and device

Abstract

The application discloses a MOS tube control method and device. The gate of the MOS tube is used for receiving a first driving current. The first driving current is used for controlling the MOS tube to be turned off or turned on. The MOS tube control method comprises the following steps: detecting a voltage change rate of the drain of the MOS tube; when the MOS tube is turned off, determining whether the voltage change rate is greater than a preset change rate; in response to the voltage change rate being greater than the preset change rate, outputting a driving instruction according to the voltage change rate; generating a second driving current according to the voltage change rate; when the driving instruction is received, inputting the second driving current to the gate of the MOS tube; wherein the current direction of the second driving current is opposite to the current direction of the first driving current, and the second driving current is used for reducing the turn-off speed of the MOS tube. The application can realize fine control of the turn-off speed of the MOS tube when the MOS tube is turned off.

Description

Technical Field

[0001] This application relates to the field of MOSFET driving technology, specifically to a MOSFET control method and apparatus. Background Technology

[0002] Existing high-speed MOSFETs are prone to large voltage changes during turn-off, which can lead to large voltage spikes and voltage oscillations in the MOSFET. These large voltage spikes and oscillations can easily damage the MOSFET and generate strong electromagnetic interference, thus affecting the stability of the system containing the MOSFET.

[0003] To address the issue of significant voltage fluctuations during the turn-off process of MOSFETs, existing technologies employ multiple gate resistors. By switching the connection between different gate resistors and the MOSFET during the turn-off phase, voltage spikes and voltage oscillation slopes are reduced. Alternatively, existing technologies use multiple gate voltages, driving the MOSFET with different voltages during the turn-off phase. However, neither multiple gate resistors nor multiple gate voltages can provide precise control over the MOSFET's turn-off speed. Summary of the Invention

[0004] Therefore, this application provides a MOSFET control method and apparatus for achieving fine-grained control of the MOSFET's turn-off speed. The technical solution of this application is as follows:

[0005] In a first aspect, this application provides a MOSFET control method, wherein the gate of the MOSFET is used to receive a first drive current, the first drive current being used to control the MOSFET to turn off or on, the method comprising: detecting the voltage change rate of the drain of the MOSFET; determining whether the voltage change rate is greater than a preset change rate when the MOSFET is turned off; outputting a drive command according to the voltage change rate in response to the voltage change rate being greater than the preset change rate; generating a second drive current according to the voltage change rate; and inputting the second drive current to the gate of the MOSFET when the drive command is received; wherein the current direction of the second drive current is opposite to the current direction of the first drive current, and the second drive current is used to reduce the turn-off speed of the MOSFET.

[0006] In one embodiment of this application, generating a second drive current based on the voltage change rate includes: generating an initial voltage based on the voltage change rate; amplifying the initial voltage by a preset power factor to obtain a target voltage; and controlling the target voltage to pass through a target resistor with a preset resistance value to generate the second drive current.

[0007] In one embodiment of this application, the peak current of the second driving current is less than the peak current of the first driving current.

[0008] In one embodiment of this application, the duration of the second driving current is shorter than the duration of the first driving current.

[0009] Secondly, this application provides a MOSFET control device. The gate of the MOSFET is used to receive a first drive current, which is used to control the MOSFET to turn off or on. The MOSFET control device includes a voltage change rate detection module, a control module, and a second drive module. The voltage change rate detection module is connected to the drain of the MOSFET and is used to detect the voltage change rate of the drain of the MOSFET. The control module is electrically connected to the voltage change rate detection module and is used to: determine whether the voltage change rate is greater than a preset change rate when the MOSFET is turned off; and output a second drive command according to the voltage change rate in response to the voltage change rate being greater than the preset change rate. The first drive module is electrically connected to the gate of the MOSFET and is used to: generate a second drive current according to the voltage change rate; and input the second drive current to the gate of the MOSFET when the second drive command is received. The direction of the second drive current is opposite to the direction of the first drive current, and the second drive current is used to reduce the turn-off speed of the MOSFET.

[0010] In one embodiment of this application, the second driving module includes a digital-to-analog converter (DAC), a power amplifier, and a current injection unit. The DAC generates an initial voltage based on the voltage change rate. The power amplifier is electrically connected to the DAC and amplifies the initial voltage by a preset factor to obtain a target voltage. The current injection unit is electrically connected to the power amplifier, the control module, and the gate of the MOS transistor. The current injection unit is used to: control the target voltage to pass through a target resistor with a preset resistance value to generate the second driving current; and input the second driving current to the gate of the MOS transistor upon receiving the second driving command.

[0011] In one embodiment of this application, the MOS transistor control device further includes a first driving module, which is connected to the control module and the gate of the MOS transistor respectively, and is used to: receive a first driving command transmitted by the control module, and generate the first driving current according to the first driving command.

[0012] In one embodiment of this application, the first driving module includes a push-pull driving circuit, and the first driving current includes a first positive current and a first negative current; the MOS transistor turns on in response to the first positive current and turns off in response to the first negative current.

[0013] In one embodiment of this application, the second driving current includes a second positive current, the peak value of which is less than the peak value of the first negative current.

[0014] In one embodiment of this application, the MOS transistor is a silicon carbide MOS transistor.

[0015] The beneficial effects of the technical solution provided in this application include at least the following: when the MOSFET is turned off, if the voltage change rate of the MOSFET is detected to be greater than a preset change rate, a second driving current opposite to the current direction of the first driving current is input to the gate of the MOSFET, thereby reducing the peak current of the first driving current, reducing the speed at which the first driving current controls the MOSFET to turn off, thereby reducing the voltage spikes and voltage oscillations of the MOSFET, and the second driving current is adjustable according to the real-time voltage value of the MOSFET, thereby achieving fine control of the MOSFET's turn-off speed. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of a MOS transistor control module provided in an embodiment of this application.

[0017] Figure 2 This is a flowchart illustrating a MOS transistor control method provided in an embodiment of this application.

[0018] Figure 3 This is a flowchart illustrating a second driving current generation method provided in an embodiment of this application.

[0019] Figure 4 This is a schematic diagram of the structure of a MOS transistor control device provided in an embodiment of this application.

[0020] Figure 5 This is a schematic diagram of the structure of a second driving module provided in an embodiment of this application.

[0021] Figure 6 This is a schematic diagram of another MOS transistor control device provided in the embodiments of this application.

[0022] Figure 7 This is a schematic diagram of a preferred MOS transistor control device provided in an embodiment of this application.

[0023] Figure 8 This is a schematic diagram of the structure of a voltage change rate detection module provided in an embodiment of this application.

[0024] Figure 9 This is a schematic diagram of the structure of a power amplifier unit provided in an embodiment of this application.

[0025] Figure 10 This is a schematic diagram of the structure of a current injection unit provided in an embodiment of this application.

[0026] Figure 11 This is a schematic diagram of the structure of a push-pull drive module provided in an embodiment of this application. Detailed Implementation

[0027] It should be noted that in the embodiments of this application, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone, where A and B can be singular or plural. The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and drawings of this application are used to distinguish similar objects, not to describe a specific order or sequence.

[0028] It should also be noted that the methods disclosed in the embodiments of this application or the methods shown in the flowcharts include one or more steps for implementing the method. Without departing from the scope of the claims, the execution order of multiple steps can be interchanged, and some steps can also be deleted.

[0029] Currently, with the continuous advancement of semiconductor technology, existing semiconductor devices possess advantages such as lower on-resistance, adaptability to higher operating temperatures, and faster switching speeds. This includes MOSFETs (metal-oxide-semiconductor FETs). While MOSFETs offer advantages due to their faster switching speeds, they also introduce drawbacks.

[0030] In other words, MOSFETs with high switching speeds are prone to large voltage changes during the turn-off process, which can lead to large voltage spikes and voltage oscillations in the MOSFET. Large voltage spikes and voltage oscillations can easily damage the MOSFET and generate strong electromagnetic interference, thus affecting the stability of the system containing the MOSFET.

[0031] To address the issue of significant voltage fluctuations during the turn-off process of MOSFETs, existing technologies employ multiple gate resistors. By switching the connection between different gate resistors and the MOSFET during the turn-off phase, voltage spikes and voltage oscillation slopes are reduced. Alternatively, existing technologies use multiple gate voltages, driving the MOSFET with different voltages during the turn-off phase. However, both multiple gate resistors and multiple gate voltages increase the complexity of the MOSFET driving circuit and prevent precise control over the MOSFET's turn-off speed.

[0032] This application provides a MOSFET control method and a MOSFET control device to achieve fine control of the MOSFET's turn-off speed and reduce the complexity of the MOSFET drive circuit.

[0033] Please refer to Figure 1 This is a schematic diagram of a MOS transistor control module provided in an embodiment of this application. The MOS transistor control module 100 includes a control unit 110, a first driving unit 120, and a second driving unit 130. The control unit 110 is connected to the drain D of the MOS transistor 101. The first driving unit 120 is connected to both the control unit 110 and the gate G of the MOS transistor 101. The second driving unit 130 is connected to both the control unit 110 and the gate G of the MOS transistor 101.

[0034] Next, combined Figure 1 This application introduces a MOSFET control method based on an embodiment of the present application. See details for further information. Figure 2 This is a flowchart illustrating a MOS transistor control method provided in an embodiment of this application. The gate of the MOS transistor receives a first drive current, which is used to control the MOS transistor to turn off or on. The method specifically includes the following steps:

[0035] Step S21: Detect the rate of change of voltage at the drain of the MOSFET.

[0036] In this embodiment of the application, the aforementioned first driving current can be generated by... Figure 1 The first driving unit provides that the control unit can send a first driving command to the first driving unit, causing the first driving unit to output a first driving current to the gate of the MOSFET, thereby controlling the source and drain of the MOSFET to be turned off or on. This first driving current can include high / low level signals, or positive / negative current signals, etc., signals with frequency, thereby controlling the source and drain of the MOSFET to switch between off and on according to the frequency.

[0037] The control unit can acquire the voltage change rate of the drain of the MOSFET through a differentiating circuit composed of resistors and capacitors, and then calculate the real-time voltage value based on the voltage change rate, the resistance value of the resistor in the differentiating circuit and the capacitance value of the capacitor.

[0038] Alternatively, the control unit can also collect the real-time voltage value of the drain of the MOSFET at a preset time interval through a voltage acquisition circuit, and calculate the voltage change rate by using the real-time voltage values ​​at multiple time points and the preset time interval.

[0039] Step S22: When the MOSFET is turned off, determine whether the voltage change rate is greater than the preset change rate.

[0040] Step S23: In response to the voltage change rate being greater than the preset change rate, output a drive command according to the voltage change rate.

[0041] Step S24: Generate a second driving current based on the voltage change rate.

[0042] In this embodiment of the invention, the aforementioned voltage change rate can be considered as the degree of voltage change of the MOSFET after it is turned off. Since the MOSFET is in a switching state between off and on under the control of the first drive current, a large voltage change rate will result in a voltage spike with a large slope and voltage oscillation. Therefore, by setting a preset change rate, it is possible to determine whether the voltage change of the MOSFET during turn-off is too large, resulting in a voltage spike with a large slope and voltage oscillation.

[0043] Once the control unit obtains the current rate of change of voltage at the drain of the MOSFET, it can immediately compare it with a pre-stored preset rate of change. When it determines that the current rate of change of voltage is greater than the preset rate of change, it can generate a drive command and send it to the second drive unit.

[0044] After receiving the voltage change rate transmitted by the control unit, the second drive unit generates a second drive current based on the voltage change rate. Before receiving a drive command, the second drive current is not transmitted to the gate of the MOS transistor.

[0045] Step S25: Upon receiving a drive command, input the second drive current to the gate of the MOSFET.

[0046] In this embodiment, after receiving the drive command, the second drive unit can promptly input it to the gate of the MOSFET. That is, at the current time, the gate of the MOSFET simultaneously receives both the first drive current and the second drive current. The direction of the second drive current is opposite to that of the first drive current, and the second drive current is used to reduce the turn-off speed of the MOSFET. Since the first drive current is currently used to control the MOSFET to turn off, the peak value of the first drive current is reduced after it is partially canceled out, thereby reducing the turn-off speed of the MOSFET.

[0047] In this embodiment, when the MOSFET is turned off, if the voltage change rate of the MOSFET is detected to be greater than a preset change rate, a second driving current opposite to the current direction of the first driving current is input to the gate of the MOSFET, thereby reducing the peak current of the first driving current and reducing the speed at which the first driving current controls the MOSFET to turn off, thereby reducing the voltage spikes and voltage oscillations of the MOSFET. Furthermore, the second driving current is adjustable according to the real-time voltage value of the MOSFET, thereby achieving fine control of the MOSFET's turn-off speed.

[0048] The peak value of the second drive current is less than the peak value of the first drive current. Specifically, the control unit can adjust the peak value of the second drive current. After obtaining the voltage change rate of the MOSFET, the control unit adjusts the peak value of the second drive current based on this rate. Alternatively, the control unit can obtain the peak value of the first drive current from the first drive unit and control the second drive unit accordingly, so that the second drive unit adjusts the peak value of the output second drive current to be less than the peak value of the first drive current.

[0049] Since the peak value of the first drive current is greater than that of the second drive current, and the direction of the second drive current is opposite to that of the first drive current, the second drive current can partially offset the first drive current, thereby reducing the peak value of the first drive current and thus reducing the turn-off speed of the MOSFET controlled by the first drive current. Furthermore, the control unit can finely adjust the peak value of the second drive current to precisely control the turn-off speed of the MOSFET.

[0050] In this embodiment, the duration of the second drive current may be shorter than the duration of the first drive current. It is understood that the MOSFET is controlled to turn off by receiving the first drive current through its gate, and the turn-off time is determined by the duration of the first drive current. Therefore, by adjusting the duration of the second drive current used to offset it, the turn-off speed of the MOSFET can be finely controlled. The duration of the second drive current is shorter than the duration of the first drive current to ensure that the first drive current can smoothly turn off the MOSFET.

[0051] Please refer to Figure 3 This is a flowchart illustrating a second driving current generation method provided in an embodiment of this application. The method is one implementation of step S22 described above, and specifically includes the following steps:

[0052] Step S31: Generate the initial voltage based on the voltage change rate.

[0053] In this embodiment, the second driving unit, after receiving the real-time voltage value transmitted by the control unit, can generate an initial voltage. The initial voltage value can be obtained from the voltage change rate; for example, the real-time voltage value of the MOSFET can be obtained first from the voltage change rate, and the initial voltage can be equal to this real-time voltage value. The second driving unit may include a digital-to-analog converter circuit to convert the real-time voltage value into the relevant initial voltage.

[0054] Step S32: Amplify the initial voltage by a preset power factor to obtain the target voltage.

[0055] In this embodiment, the second driving unit can further adjust the magnitude of the initial voltage. To delay the turn-off speed as needed, the second driving unit can amplify the initial voltage to obtain the target voltage. That is, by adjusting the magnitude of the target voltage, the peak current of the second driving current can be adjusted, thereby finely controlling the turn-off speed of the MOSFET.

[0056] The second drive unit may include a power amplifier circuit with an adjustable resistor to adjust the amplification factor, thereby finely adjusting the target voltage and the turn-off speed of the MOSFET.

[0057] Step S33: Control the target voltage to pass through the target resistor with a preset resistance value to generate the second driving current.

[0058] In this embodiment, the target resistor can also be an adjustable resistor. By adjusting the resistance value, the magnitude of the second drive current can be further adjusted. It is understood that the digital-to-analog converter circuit, power amplifier circuit, and target resistor in the second drive unit are only one implementation method, and all can be controlled by the control unit via commands; therefore, no limitation is made here.

[0059] Please refer to Figure 4 This is a schematic diagram of a MOS transistor control device provided in an embodiment of this application. The gate of the MOS transistor 401 is used to receive a first drive current, which is used to control the MOS transistor to turn off or on. Specifically, the MOS transistor control device 400 includes a voltage change rate detection module 410, a control module 420, and a second drive module 430.

[0060] In this embodiment, the voltage change rate detection module 410 is connected to the drain of the MOS transistor 401 and the control module 420, respectively. The control module 420 is connected to the second driving module 430, and the second driving module 430 is connected to the gate of the MOS transistor 401.

[0061] The voltage change rate detection module 410 is used to detect the voltage change rate at the drain of the MOSFET 401 and transmit the voltage change rate to the control module 420.

[0062] The control module 420 is configured to: determine whether the voltage change rate is greater than a preset change rate when the MOS transistor 401 is turned off, and output a second drive command according to the voltage change rate in response to the voltage change rate being greater than the preset change rate.

[0063] The second drive module 430 is used to: generate a second drive current according to the voltage change rate, and input the second drive current to the gate of the MOS transistor 401 when a second drive command is received, so as to reduce the turn-off speed of the MOS transistor 401.

[0064] The direction of the second driving current is opposite to that of the first driving current, and the second driving current is used to reduce the turn-off speed of the MOS transistor.

[0065] In this embodiment, the direction of the first driving current is opposite to the direction of the second driving current. The functions of the voltage change rate detection module 410, control module 420, and second driving module 430 described above can be found in the relevant sections of the foregoing embodiments, and will not be repeated here.

[0066] Please refer to Figure 5This is a schematic diagram of the structure of a second driving module provided in an embodiment of this application. The second driving module 500 includes a digital-to-analog conversion unit 510, a power amplification unit 520, and a current injection unit 530.

[0067] The digital-to-analog conversion unit 510 is connected to the control module and the power amplification unit 520, the power amplification unit 520 is connected to the current injection unit 530, and the current injection unit 530 is connected to the control module and the gate of the MOS transistor.

[0068] The digital-to-analog converter 510 generates an initial voltage based on the voltage change rate. The power amplifier 520 amplifies the initial voltage by a preset factor to obtain a target voltage. The current injection unit 530 controls the target voltage to pass through a target resistor of a preset value to generate the second drive current, and inputs the second drive current to the gate of the MOS transistor upon receiving the second drive command.

[0069] Please see Figure 6 This is a schematic diagram of another MOS transistor control device provided in an embodiment of this application. Figure 6 The MOSFET control device 600 includes a voltage change rate detection module 610, a control module 620, and a second drive module 630, which are connected to... Figure 4 The voltage change rate detection module 410, control module 420 and second drive module 430 of the MOS transistor control device 400 are the same or similar, so they will not be described in detail. Figure 6 The MOS transistor control device 600 shown is... Figure 4 The difference between the MOSFET control device 400 shown is that... Figure 6 The MOS transistor control device 600 shown also includes:

[0070] A first driving module 640 is connected to both the control module and the gate of the MOSFET. The first driving module 640 receives a first driving command transmitted from the control module, generates a first driving current based on the first driving command, and transmits it to the gate of the MOSFET.

[0071] In this embodiment, the control module 620 can send a first drive command to the first drive module 640, causing the first drive module 640 to output a first drive current to the gate G of the MOSFET, thereby controlling the source S and drain D of the MOSFET 601 to be turned off or on. This first drive current can include high / low level signals, or positive / negative current signals, etc., signals with frequency, thereby controlling the source and drain of the MOSFET to switch between off and on according to this frequency.

[0072] The first driving module 640 can be a push-pull driving circuit. The first driving current includes a first positive current and a first negative current, and the second driving current includes a second positive current. That is, by controlling the push-pull driving circuit, it can alternately output the first positive current and the first negative current at a preset frequency. The MOSFET 601 turns on in response to the first positive current and turns off in response to the first negative current.

[0073] When the voltage change rate is large when the MOSFET 601 is turned off, the second positive current value of the gate of the MOSFET 601 can be output by the second driving module 630. The peak value of the second positive current is smaller than the peak value of the first negative current, so that a part of the first negative current can be canceled by the second positive current, thereby reducing the peak value of the first negative current and slowing down the turn-off speed of the MOSFET 601.

[0074] Please see Figure 7 This is a schematic diagram of a preferred MOSFET control device provided in an embodiment of this application. The MOSFET control device 700 includes a voltage change rate detection module 710, a control module 720, a signal conversion module 730, a digital-to-analog conversion unit 740, a power amplification unit 750, a current injection unit 760, and a push-pull drive module 770.

[0075] The voltage change rate detection module 710 is connected to the drain (D) of the MOSFET 701 and the control module 720. The control module 720 is connected to the signal conversion module 730 and the digital-to-analog converter (DAC) unit 740. The signal conversion module 730 is connected to the push-pull drive module 770 and the current injection unit 760. The push-pull drive module 770 is connected to the gate (G) of the MOSFET 701. The DAC unit 740 is connected to the power amplifier unit 750. The power amplifier unit 750 is connected to the current injection unit 760. The current injection unit 760 is connected to the gate (G) of the MOSFET 701.

[0076] In this embodiment, detailed functional descriptions of the voltage change rate detection module 710, control module 720, digital-to-analog converter unit 740, power amplifier unit 750, current injection unit 760, and push-pull drive module 770 can be found in the descriptions of the corresponding parts in the foregoing embodiments, and will not be repeated here. The signal conversion module 730 is used to convert the control commands of the control module 720 into a carrier signal of a preset type, such as a pulse width modulation signal (PWM signal).

[0077] Among them, such as Figure 8 As shown, the voltage change rate detection module 710 can be a CR differential sampling circuit, including a first capacitor C1 and a first resistor R1. One end of the first capacitor C1 is connected to the drain D of the MOSFET 701, and the other end is connected to the control module 720. One end of the first resistor R1 is connected to the control module 720, and the other end is grounded. The voltage change rate A of the drain D of the MOSFET 701 can be obtained through this RC differential sampling circuit. The control module 720 can obtain the real-time voltage value V1 according to the preset algorithm V1 = C1 × A × R1.

[0078] Among them, such as Figure 9 As shown, the power amplifier unit 750 includes a second resistor R2, a third resistor R3, and an operational amplifier OP. One end of the second resistor R2 is connected to the negative input terminal of the operational amplifier OP, and the other end is grounded. One end of the third resistor R3 is connected to the negative input terminal of the operational amplifier OP, and the other end is connected to the output terminal of the operational amplifier OP. The positive input terminal of the operational amplifier OP is connected to the digital-to-analog converter unit 740, and its output terminal is connected to the current injection unit 760. The initial voltage is the voltage input to the positive input terminal of the digital-to-analog converter unit 740, and the target voltage is the output voltage.

[0079] Among them, such as Figure 10 As shown, the current injection unit 760 includes a first MOSFET PMOS1, a second MOSFET NMOS2, a fourth resistor R4, a fifth resistor R5, and a diode D1. The source S of the first MOSFET PMOS1 is connected to the power amplifier unit 750, and its drain D is connected to the anode of diode D1 through the fifth resistor R5. The cathode of diode D1 is connected to the gate G of MOSFET 701. The gate G of the first MOSFET PMOS1 is connected to the drain D of the second MOSFET NMOS2. The gate G of the second MOSFET NMOS2 is connected to the signal conversion module 730, and its source S is grounded. One end of the fourth resistor is connected to the source S of the first MOSFET PMOS1, and the other end is connected to the gate G of the first MOSFET PMOS1.

[0080] When the signal conversion module 730 transmits a high level to the gate G of the second MOS transistor NMOS2, the second MOS transistor NMOS2 is turned on, and the first MOS transistor PMOS1 is turned on. The target voltage transmitted by the power amplifier unit 750 is transmitted through the fifth resistor R5 and generates a second positive current that is transmitted to the gate of the MOS transistor 701.

[0081] Among them, such as Figure 11 As shown, the push-pull drive module 770 includes a first transistor NPN1, a second transistor PNP1, a first power supply VCC, a second power supply VEE, a sixth resistor Rgon, and a seventh resistor Rgoff. The bases of the first transistor NPN1 and the second transistor PNP1 are connected to the signal conversion module 730. The collector of the first transistor NPN1 is connected to the first power supply VCC, and the emitter is connected to the gate G of the MOSFET 701 through the sixth resistor Rgon. The collector of the second transistor PNP1 is connected to the first power supply VCC, and the emitter is connected to the gate G of the MOSFET 701 through the seventh resistor Rgoff.

[0082] When the signal conversion module 730 transmits a high level, the first transistor NPN1 is turned on, outputting a first positive current. When the signal conversion module 730 transmits a low level, the second transistor PNP1 is turned on, outputting a first negative current.

[0083] In this embodiment, the MOSFET 701 is a silicon carbide MOSFET. Silicon carbide MOSFETs have a faster turn-off speed. In this application, when the voltage change rate of the silicon carbide MOSFET is detected to be greater than a preset change rate during turn-off, a second drive current opposite in direction to the first drive current is input to the gate of the silicon carbide MOSFET. This reduces the peak value of the first drive current, thereby reducing the turn-off speed of the silicon carbide MOSFET controlled by the first drive current. This reduces voltage spikes and voltage oscillations in the silicon carbide MOSFET. Furthermore, the second drive current is adjustable according to the real-time voltage value of the silicon carbide MOSFET, thus achieving fine-grained control of the turn-off speed of the silicon carbide MOSFET.

[0084] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially as a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer storage medium or transmitted through the computer storage medium. The computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available media may be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., digital versatile discs (DVDs)), or semiconductor media (e.g., solid-state disks (SSDs)).

[0085] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. This program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the methods described above. The aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks. Unless otherwise specified, the technical features of this embodiment and its implementation can be combined arbitrarily.

[0086] The embodiments described above are merely preferred embodiments of this application and are not intended to limit the scope of this application. Any modifications and improvements made by those skilled in the art to the technical solutions of this application without departing from the spirit of this application should fall within the protection scope defined by the claims of this application.

Claims

1. A method for controlling a MOS transistor, wherein the gate of the MOS transistor is used to receive a first drive current, the first drive current being used to control the MOS transistor to turn off or on, characterized in that, The method includes: The rate of change of voltage at the drain of the MOS transistor is detected; When the MOS transistor is turned off, determine whether the voltage change rate is greater than a preset change rate; In response to the voltage change rate being greater than the preset change rate, a drive command is output according to the voltage change rate; A second driving current is generated based on the voltage change rate; Upon receiving the drive command, the second drive current is input to the gate of the MOS transistor; The direction of the second driving current is opposite to the direction of the first driving current when the MOS transistor is turned off. The second driving current is used to reduce the peak value of the first driving current, thereby reducing the turn-off speed of the MOS transistor.

2. The MOS transistor control method as described in claim 1, characterized in that, The step of generating the second drive current based on the voltage change rate includes: An initial voltage is generated based on the voltage change rate. The initial voltage is amplified by a preset power factor to obtain the target voltage; The target voltage is controlled to pass through a target resistor with a preset resistance value to generate the second driving current.

3. The MOS transistor control method as described in claim 1, characterized in that, The peak value of the second drive current is less than the peak value of the first drive current.

4. The MOS transistor control method as described in claim 1, characterized in that, The duration of the second drive current is shorter than the duration of the first drive current.

5. A MOS transistor control device, wherein the gate of the MOS transistor is used to receive a first drive current, the first drive current being used to control the MOS transistor to turn off or on, characterized in that, The MOS transistor control device includes a voltage change rate detection module, a control module, and a second drive module. The voltage change rate detection module is connected to the drain of the MOS transistor and is used to detect the voltage change rate at the drain of the MOS transistor. The control module is electrically connected to the voltage change rate detection module and is used for: When the MOS transistor is turned off, determine whether the voltage change rate is greater than a preset change rate; In response to the voltage change rate being greater than the preset change rate, a second drive command is output according to the voltage change rate; The second driving module is electrically connected to the gate of the MOS transistor and is used for: A second driving current is generated based on the voltage change rate; Upon receiving the second drive command, the second drive current is input to the gate of the MOS transistor; The direction of the second driving current is opposite to the direction of the first driving current when the MOS transistor is turned off. The second driving current is used to reduce the peak value of the first driving current, thereby reducing the turn-off speed of the MOS transistor.

6. The MOS transistor control device as described in claim 5, characterized in that, The second drive module includes a digital-to-analog converter, a power amplifier, and a current injection unit; The digital-to-analog conversion unit is used to generate an initial voltage based on the voltage change rate; The power amplification unit is electrically connected to the digital-to-analog conversion unit and is used to amplify the initial voltage by a preset factor to obtain the target voltage; The current injection unit is electrically connected to the power amplification unit, the control module, and the gate of the MOS transistor. The current injection unit is used for: The target voltage is controlled to pass through a target resistor with a preset resistance value to generate the second driving current; Upon receiving the second drive command, the second drive current is input to the gate of the MOS transistor.

7. The MOS transistor control device as described in claim 5, characterized in that, The MOS transistor control device further includes a first driving module, which is connected to both the control module and the gate of the MOS transistor, and is used for: The system receives the first drive command transmitted by the control module and generates the first drive current according to the first drive command.

8. The MOS transistor control device as described in claim 7, characterized in that, The first driving module includes a push-pull driving circuit, and the first driving current includes a first positive current and a first negative current; The MOS transistor turns on in response to the first positive current and turns off in response to the first negative current.

9. The MOS transistor control device as described in claim 8, characterized in that, The second driving current includes a second positive current, the peak value of which is less than the peak value of the first negative current.

10. The MOS transistor control device according to any one of claims 5 to 9, characterized in that, The MOS transistor is a silicon carbide MOS transistor.

Images