Driving circuit of high-efficiency silicon carbide MOSFET

Abstract

The utility model discloses a drive circuit of a high-efficiency silicon carbide MOSFET. The drive circuit comprises a voltage isolation conversion circuit unit, a voltage reduction conversion circuit unit and a drive circuit unit. The voltage isolation conversion circuit unit is used for voltage isolation and converting the isolated voltage into an equal voltage and a reference negative voltage to the ground; the step-down conversion circuit unit is connected with the voltage isolation conversion circuit unit, and the step-down conversion circuit unit is used for reducing the isobaric voltage converted from the isolation voltage; and the driving circuit unit is connected with the voltage isolation conversion circuit unit and the voltage reduction conversion circuit unit and is used for driving a silicon carbide MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor). According to the utility model, the isolation power supply is adopted for power supply, system faults caused by the problems of the power supply input end can be avoided, and the stability and reliability of the system are improved. Besides, the input and the output of the isolation power supply are not electrically connected, so that the interference of a ground wire can be effectively cut off, the influence of a ground wire loop can be eliminated, and the electromagnetic compatibility of the system is improved.

Description

Technical Field

[0001] The utility model relates to the field of MOSFET drive circuits, in particular to a high-efficiency silicon carbide MOSFET drive circuit. Background Art

[0002] With the development of power electronics technology, silicon carbide MOSFET has become increasingly widely used in the field of power electronics with high performance and high reliability requirements due to its advantages such as small size, high frequency, low loss, high temperature resistance and high voltage.

[0003] Existing SiC drive circuits are inefficient when operating in high-frequency, high-temperature environments, failing to fully exploit the advantages of SiC devices. Furthermore, because SiC devices operate at high temperatures and high pressures, existing drive circuits often struggle to maintain long-term stable operation and are prone to failure. Utility Model Content

[0004] The purpose of the utility model is to provide a high-efficiency silicon carbide MOSFET driving circuit to improve the stability of the silicon carbide MOSFET driving circuit and reduce the switching loss of the silicon carbide MOSFET.

[0005] In order to solve the above technical problems, the utility model provides a high-efficiency silicon carbide MOSFET driving circuit, including a voltage isolation conversion circuit unit, a step-down conversion circuit unit and a driving circuit unit;

[0006] The voltage isolation conversion circuit unit is used for voltage isolation and converting the isolated voltage into an equal voltage and a negative voltage referenced to the ground;

[0007] The step-down conversion circuit unit is connected to the voltage isolation conversion circuit unit, and the step-down conversion circuit unit steps down the voltage converted from the isolation voltage;

[0008] The driving circuit unit is connected to the voltage isolation conversion circuit unit and the step-down conversion circuit unit, and is used to drive the silicon carbide MOSFET.

[0009] Furthermore, the voltage isolation conversion circuit unit includes two voltage conversion modules, and the two voltage conversion modules respectively isolate and output an equal voltage and a ground reference negative voltage.

[0010] Furthermore, the voltage conversion module adopts WRB2424S-3WR2A chip and WRF2403S-3WR2A chip.

[0011] Furthermore, the input end of the step-down conversion circuit unit is connected to the equal-voltage output end of the voltage isolation conversion circuit unit, and step-down conversion is performed.

[0012] Furthermore, the step-down conversion circuit unit adopts a voltage conversion chip TPS5430.

[0013] Furthermore, the driving circuit unit includes a driving optocoupler and a driving chip;

[0014] The optical coupler driver is used to detect the driving signal and isolate the driving signal and output it to the driving chip;

[0015] The driver chip is connected to the driver optocoupler, and the driver chip is used to convert the drive signal into a drive source for driving the silicon carbide MOSFET.

[0016] Furthermore, the model of the driving optocoupler is LTV-W137A-TAI.

[0017] Furthermore, the model of the driver chip is IXDI609SIA.

[0018] Compared with the prior art, the present invention has at least the following beneficial effects:

[0019] This utility model uses an isolated power supply to prevent system failures caused by problems with the power input, thereby increasing system stability and reliability. Furthermore, the lack of electrical connection between the input and output of the isolated power supply effectively cuts off ground interference and eliminates the effects of ground loops, improving the system's electromagnetic compatibility.

[0020] Furthermore, the drive circuit adopts a negative voltage design, which can quickly and completely shut down the SiC MOSFET, thereby reducing the switching losses of the SiC MOSFET. In addition, the turn-on voltage of the MOSFET decreases with rising temperature. The negative voltage drive can further ensure that the device will not be mis-turned on due to gate crosstalk, thereby improving the stability of the SiC MOSFET switch. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the overall structure of the driving circuit of the high-performance silicon carbide MOSFET of the utility model;

[0022] Figure 2 This is a schematic diagram of the circuit structure of the voltage isolation conversion circuit unit of the high-performance silicon carbide MOSFET drive circuit of the utility model;

[0023] Figure 3 This is a schematic diagram of the structure of the buck conversion circuit unit of the high-performance silicon carbide MOSFET drive circuit of the utility model;

[0024] Figure 4 This is a schematic diagram of the structure of a driving circuit unit of a high-performance silicon carbide MOSFET driving circuit of the utility model. DETAILED DESCRIPTION

[0025] The following is a more detailed description of the high-performance silicon carbide MOSFET drive circuit of the present invention, with reference to a schematic diagram. This diagram illustrates a preferred embodiment of the present invention. It should be understood that those skilled in the art may modify the present invention described herein while still achieving the beneficial effects of the present invention. Therefore, the following description should be understood as a general guideline for those skilled in the art and not as a limitation of the present invention.

[0026] The following paragraphs describe the present invention in more detail by way of example with reference to the accompanying drawings. The advantages and features of the present invention will become more apparent from the following description and claims. It should be noted that the drawings are greatly simplified and not to exact scale, and are intended solely to facilitate and clearly illustrate the embodiments of the present invention.

[0027] like Figures 1 to 4 As shown, an embodiment of the present invention proposes a high-efficiency silicon carbide MOSFET driving circuit, including a voltage isolation conversion circuit unit, a step-down conversion circuit unit and a driving circuit unit.

[0028] Specifically, the voltage isolation conversion circuit unit is used for voltage isolation and converting the isolated voltage into an equal voltage and a negative voltage referenced to the ground.

[0029] The step-down conversion circuit unit is connected to the voltage isolation conversion circuit unit, and the step-down conversion circuit unit steps down the voltage converted from the isolation voltage.

[0030] The driving circuit unit is connected to the voltage isolation conversion circuit unit and the step-down conversion circuit unit, and is used to drive the silicon carbide MOSFET.

[0031] In this embodiment, the voltage isolation conversion circuit unit includes two isolation voltage modules, which provide power for the step-down conversion circuit unit and the driving circuit unit. The step-down conversion circuit unit then steps down the voltage of the voltage isolation conversion circuit unit to the voltage required by the driving circuit unit. Finally, under normal power supply conditions, when the driving circuit unit receives the MOSFET driving signal, the driving circuit unit drives the silicon carbide MOSFET to operate.

[0032] Furthermore, the voltage isolation conversion circuit unit includes two voltage conversion modules, and the two voltage conversion modules respectively isolate and output an equal voltage and a ground reference negative voltage.

[0033] Specifically, the voltage isolation conversion circuit unit isolates the voltage, preventing each group of drive circuits from interfering with each other and driving independently. This conversion circuit includes two voltage conversion modules, which use the WRB2424S-3WR2A chip and the WRF2403S 3TVR2A chip, respectively PWR1 and PWR2.

[0034] PWR1 is a 24V to 24V isolated power module with a power of 3W. It ensures that the power is sufficient to provide enough power to the drive circuit to drive the MOS tube.

[0035] Due to its material properties, silicon carbide requires negative voltage to completely shut down during switching. PWR2 is an isolated power module that converts 24V to 3.3V. The positive terminal of the 3.3V output is connected to GNDA, making the 3.3V output voltage -3.3V relative to the reference ground. This provides negative voltage to shut down the silicon carbide.

[0036] The voltage isolation conversion circuit includes capacitors C4 and C5. For example, C4 is 10μF and is connected between pins 2 and 1 at the 24V input, which plays the role of filtering and energy storage. C5 is 100nF to filter out high-frequency noise.

[0037] PWR1 provides a 24V isolated voltage conversion, with pin 6 serving as the positive output, generating a +24V voltage. PWR2 provides a 3.3V isolated voltage conversion. The positive output of 3.3V, pin 6 of PWR2, is connected to GNDA, making the negative output of 3.3V, pin 7 of PWR2, reference ground, -3.3V. Capacitors C1 and C6 are 10μF, and C2 and C7 are 100nF. They are connected in parallel at the outputs of the two modules, acting as energy storage filters and filtering out high-frequency noise, respectively.

[0038] Furthermore, the input end of the step-down conversion circuit unit is connected to the equal-voltage output end of the voltage isolation conversion circuit unit, and step-down conversion is performed.

[0039] Specifically, voltage converter chip U1 is a TPS5430, which performs voltage conversion. Capacitors C10 and C11 are 10μF for energy storage and filtering. Pin 7 is the positive terminal of the 24V input, and pin 6 is the reference ground for the 24V input. Capacitor C9 is a 10nF bootstrap capacitor, connected between pins 1 and 8 of U1, ensuring proper operation of the buck chip. Diode D1 is a B340A, providing reverse freewheeling. Inductor L1 is the output buck energy storage inductor, connected to pin 8 of U1, with the other end of the inductor connected to the 17V output. Resistors R1 and R2 are 13K and 1K, respectively, for voltage feedback. They are connected to the voltage output to divide the voltage, and the divided voltage is connected to pin 4 of U1. Capacitor C12 is a 10μF capacitor, and capacitor C13 is a 100nF capacitor, connected in parallel across the output, for filtering and energy storage, ensuring a smooth and stable output voltage.

[0040] Furthermore, the driving circuit unit includes a driving optocoupler and a driving chip.

[0041] Specifically, the optocoupler driver is used to detect a driving signal and isolate the driving signal and output it to the driver chip.

[0042] The driver chip is connected to the driver optocoupler, and the driver chip is used to convert the drive signal into a drive source for driving the silicon carbide MOSFET.

[0043] In this embodiment, the driver optocoupler U2 is model LTV-W137A-TAI. Pin 2 of the driver optocoupler is connected to resistor R4, and pin 3 is connected to GND. Pins 7 and 8 are connected to GNDA. Pin 6 is connected to a 17V isolated power supply via a pull-up resistor R5 on one side, and to pin 2 of the driver chip U3, pin 1 of the voltage regulator D3, and one end of the filter capacitor on the other side. Pin 5 of the driver optocoupler U2, pin 2 of the voltage regulator D3, the other end of the filter capacitor C14, and pins 4 and 5 of the driver chip U3 are all connected to a 3.3V isolated power supply. Pins 1 and 8 of the driver chip U3 are connected to a 17V isolated power supply. One end of the driver resistor R6 is connected to pin 7 of the driver chip U3, and the other end is connected to the G terminal of the MOSFET. The driver resistor R5 and the freewheeling diode D2 are connected in parallel across the driver resistor R6. The S terminal of the MOSFET is connected to GNDA.

[0044] The internal output section of this driver optocoupler consists of an AND gate and a transistor. The transistor's emitter is connected to pin 5 and its collector is connected to pin 6. When a drive signal enters the optocoupler and the outputs of pins 7 and 8 are both 1, the AND gate output is 1, the transistor turns on, and the output of pin 6 is low. When no drive signal enters the optocoupler, pins 7 and 8 cannot both output 1. The AND gate output is 0, the transistor turns off, and the output of pin 6 is high.

[0045] Drive isolation optocouplers, through their unique operating principles and structural design, provide multiple functions such as signal isolation, anti-interference, and circuit protection. These functions are crucial to ensuring the stable operation and extending the service life of electronic equipment.

[0046] Driver chip U3 is IXDI609SIA. The input and output signals of the driver chip have opposite levels. However, due to the structure of this circuit, the signal level is flipped from before driving the optocoupler to after driving the optocoupler. After flipping once, it is sent to the driver chip, and the output signal of the driver chip is flipped again. Therefore, the level signal output to the MOS tube is consistent with the level signal input before the optocoupler.

[0047] The D3 voltage regulator is MM1Z5V6. Due to the presence of the voltage regulator, when an interference signal enters, the peak voltage of the interference signal will be clamped to around 5V, acting as a clamping protection. C14 is a filter capacitor that filters out high-frequency noise, making the input drive signal smoother. R3 is a pull-up resistor, which provides a +17V output high-level capability for driving the optocoupler output. The driver chip U3 is IXDI609SIA, which provides drive capability for the silicon carbide MOS tube when switching. R6 is the MOS tube turn-on drive resistor, and R5 is the MOS tube turn-off drive resistor. The discharge freewheeling diode D2 is MM1Z5V6. The design of separate turn-on and turn-off resistors can achieve the "slow opening and fast closing" function, which can greatly optimize the MOS tube drive waveform and reduce the MOS tube switching loss.

[0048] Compared with the prior art, the present invention has at least the following beneficial effects:

[0049] This utility model uses an isolated power supply to prevent system failures caused by problems with the power input, thereby increasing system stability and reliability. Furthermore, the lack of electrical connection between the input and output of the isolated power supply effectively cuts off ground interference and eliminates the effects of ground loops, improving the system's electromagnetic compatibility.

[0050] Furthermore, the drive circuit adopts a negative voltage design, which can quickly and completely shut down the SiC MOSFET, thereby reducing the switching losses of the SiC MOSFET. In addition, the turn-on voltage of the MOSFET decreases with rising temperature. The negative voltage drive can further ensure that the device will not be mis-turned on due to gate crosstalk, thereby improving the stability of the SiC MOSFET switch.

[0051] Obviously, those skilled in the art may make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if such modifications and variations fall within the scope of the claims of the present invention and their equivalents, the present invention is intended to include such modifications and variations.

Claims

1. A high-performance silicon carbide MOSFET drive circuit, characterized in that: It includes a voltage isolation conversion circuit unit, a step-down conversion circuit unit and a driving circuit unit; The voltage isolation conversion circuit unit is used for voltage isolation and converting the isolated voltage into an equal voltage and a negative voltage referenced to the ground; The step-down conversion circuit unit is connected to the voltage isolation conversion circuit unit, and the step-down conversion circuit unit steps down the voltage converted from the isolation voltage; The driving circuit unit is connected to the voltage isolation conversion circuit unit and the step-down conversion circuit unit, and is used to drive the silicon carbide MOSFET.

2. The high-performance silicon carbide MOSFET driving circuit according to claim 1, wherein: The voltage isolation conversion circuit unit includes two voltage conversion modules, and the two voltage conversion modules respectively isolate and output an equal voltage and a ground reference negative voltage.

3. The high-performance silicon carbide MOSFET driving circuit according to claim 2, wherein: The voltage conversion module adopts WRB2424S-3WR2A chip and WRF2403S-3WR2A chip.

4. The high-performance silicon carbide MOSFET driving circuit according to claim 1, wherein: The input end of the step-down conversion circuit unit is connected to the equal-voltage output end of the voltage isolation conversion circuit unit and performs step-down conversion.

5. The high-performance silicon carbide MOSFET driving circuit according to claim 4, wherein: The step-down conversion circuit unit adopts the voltage conversion chip TPS5430.

6. The high-performance silicon carbide MOSFET driving circuit according to claim 1, wherein: The driving circuit unit includes a driving optocoupler and a driving chip; The optical coupler driver is used to detect the driving signal and isolate the driving signal and output it to the driving chip; The driver chip is connected to the driver optocoupler, and the driver chip is used to convert the drive signal into a drive source for driving the silicon carbide MOSFET.

7. The high-performance silicon carbide MOSFET driving circuit according to claim 6, wherein: The model of the driving optocoupler is LTV-W137A-TAI.

8. The high-performance silicon carbide MOSFET driving circuit according to claim 6, wherein: The model of the driver chip is IXDI609SIA.

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