Silicon carbide drive circuit and silicon carbide device
By introducing a driving module, a filtering module, and a crosstalk suppression module into the silicon carbide driving circuit, the problem of negative voltage spikes during high-frequency switching of silicon carbide devices is solved, achieving fast switching of the devices and improving system efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SHENZHEN HELLO TECH ENERGY CO LTD
- Filing Date
- 2025-06-03
- Publication Date
- 2026-05-01
AI Technical Summary
In the existing technology, the problem of negative voltage spikes generated by silicon carbide devices during high-frequency switching has not been effectively solved, leading to device damage and reduced system efficiency.
A silicon carbide driving circuit was designed, including a driving module, a filtering module, and a crosstalk suppression module. By connecting the crosstalk suppression module in series between the gate and source of the power switch, the suppression measures are only activated when the negative voltage spike reaches a preset threshold, ensuring that the fast switching characteristics are not affected.
It effectively suppresses negative voltage spikes, reduces switching losses, improves system efficiency, reduces the risk of device failure, and ensures system safety.
Smart Images
Figure CN224191920U_ABST
Abstract
Description
Silicon carbide drive circuits and silicon carbide devices Technical Field
[0001] This application relates to the field of power electronics technology, and more specifically, to a silicon carbide drive circuit and a silicon carbide device. Background Technology
[0002] With the development of power electronics technology, semiconductor devices, represented by silicon carbide metal-oxide-semiconductor field-effect transistors (SiCMOSFETs), have become ideal choices for high-frequency, high-temperature, and high-power-density power electronic converters (such as home energy storage devices) due to their advantages such as high switching frequency, high switching speed, and high thermal conductivity. Compared with traditional Si-based devices, SiC MOSFETs have lower on-resistance, higher thermal conductivity, and power ratings comparable to IGBTs in terms of static characteristics; in terms of dynamic characteristics, SiC MOSFETs have faster switching speeds and higher frequency limits, which contributes to the improvement of the overall power density and efficiency of power electronic devices.
[0003] However, higher voltages and switching frequencies imply greater voltage change rates (dv / dt) and current change rates (di / dt), making SiC MOSFETs more sensitive to parasitic parameters of the circuit compared to SiC MOSFETs. Therefore, traditional SiMOSFET drive circuits are often unsuitable for SiC MOSFETs, requiring a redesign of the drive circuit specifically for SiC MOSFET characteristics. Furthermore, in bridge circuits, overcoming crosstalk caused by high-speed device operation becomes even more critical. Summary of the Invention
[0004] This application aims to at least address the technical problem of negative voltage spikes generated by high-frequency switching of silicon carbide devices in existing or related technologies.
[0005] Therefore, this application proposes a silicon carbide driving circuit and a silicon carbide device.
[0006] This application proposes a silicon carbide driving circuit, including multiple driving circuits and interconnected upper and lower bridge arms. Both the upper and lower bridge arms include power switching transistors. Each driving circuit is connected to one power switching transistor and is configured to drive the power switching transistor to turn on and off. At least one driving circuit includes a driving module, a driving resistor, a filtering module, and a crosstalk suppression module.
[0007] The driving module is connected to the gate of the power switch through the driving resistor and is configured to provide a driving signal to the power switch to drive the power switch to turn on and off.
[0008] The filtering module is connected to the gate and source of the power switch transistor respectively, and is configured to filter out spike interference between the gate and source of the power switch transistor; and
[0009] The crosstalk suppression module is connected to the gate and source of the power switch, respectively, and is configured to turn on when the power switch is turned off and the voltage difference between the source and gate of the power switch is greater than a preset threshold voltage, so as to suppress the negative voltage crosstalk spike generated when the power switch is turned off.
[0010] In some embodiments, the preset threshold voltage includes a first threshold voltage and a second threshold voltage, and the crosstalk suppression module includes:
[0011] The spike absorption unit, connected to the gate and source of the power switch, is configured to turn off when the power switch is turned on, and turn on when the power switch is turned off and the voltage difference between the source and gate of the power switch is greater than the first threshold voltage to absorb the negative voltage crosstalk spike.
[0012] The reverse clamping unit, connected to the gate and source of the power switch, is configured to be turned on when the voltage difference between the gate and source of the power switch is negative and its absolute value is greater than the second threshold voltage, so as to achieve voltage clamping.
[0013] In some implementations, the second threshold voltage is greater than the first threshold voltage, and the second threshold voltage is less than the negative voltage spike limit of the power switch.
[0014] In some embodiments, the spike absorption unit includes:
[0015] The first voltage divider resistor has one end connected to the gate of the power switch transistor;
[0016] The second voltage divider resistor has one end connected to the other end of the first voltage divider resistor and the other end connected to the source of the power switch transistor.
[0017] An absorption capacitor, one end of which is connected to the gate of the power switch transistor;
[0018] The switching transistor has its first terminal connected to the other end of the absorption capacitor and its control terminal connected to one end of the second voltage divider resistor.
[0019] The current-limiting resistor has one end connected to the second terminal of the switching transistor and the other end connected to the source terminal of the power switching transistor.
[0020] In some implementations, the switching transistor is a bipolar transistor.
[0021] In some embodiments, the reverse clamping unit includes:
[0022] A Zener diode, with its positive terminal connected to the gate of the power switch transistor;
[0023] The protection diode has its positive terminal connected to the source of the power switching transistor and its negative terminal connected to the negative terminal of the Zener diode.
[0024] In some embodiments, the filtering module includes a filter resistor and a filter capacitor connected in parallel across the gate and source terminals of the power switch.
[0025] In some embodiments, the power switch includes a SiC MOSFET.
[0026] In some embodiments, the silicon carbide drive circuit further includes a load inductor, a first power supply, and a second power supply;
[0027] One end of the load inductor is connected to the positive terminal of the second power supply, and the other end is connected to the source of the power switch of the upper bridge arm and the source of the power switch of the lower bridge arm; the drain of the power switch of the upper bridge arm is connected to the positive terminal of the first power supply, and the drain of the power switch of the lower bridge arm is connected to the negative terminals of the first power supply and the second power supply.
[0028] This application also proposes a silicon carbide device, including the aforementioned silicon carbide driving circuit.
[0029] In the silicon carbide driving circuit and silicon carbide device of this application, a crosstalk suppression module is connected in series between the gate and source of the power switch. This module does not function when the negative crosstalk spike is below a preset threshold voltage. It only activates to suppress the negative voltage spike when the negative voltage spike crosstalk reaches the preset threshold voltage. On the one hand, this suppression measure does not affect the inherent fast switching characteristics of the power switch itself, ensuring fast switching of the power switch and reducing its switching losses, while improving system efficiency. On the other hand, the crosstalk problem of the driving waveform is solved, reducing the risk of device failure caused by excessively high driving negative voltage and ensuring system safety. Attached Figure Description
[0030] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:
[0031] Figure 1 shows a schematic diagram of a silicon carbide drive circuit according to some embodiments of this application;
[0032] Figure 2 shows a schematic diagram of the circuit structure of a silicon carbide driving circuit according to some embodiments of this application;
[0033] Figure 3 shows a schematic diagram of the scenario when the upper bridge arm is turned on in a silicon carbide drive circuit according to some embodiments of this application.
[0034] Figure 4 shows a schematic diagram of the scenario when the lower bridge arm is turned on in a silicon carbide drive circuit according to some embodiments of this application.
[0035] Figure label:
[0036] The system includes a silicon carbide drive circuit 100, a drive circuit 10, a drive module 11, a drive resistor (R1), a filter module 12, a filter resistor R2, a filter capacitor C1, a crosstalk suppression module 13, a spike absorption unit 131, a first voltage divider resistor R3, a second voltage divider resistor R4, an absorption capacitor C2, a switching transistor Q1, a current limiting resistor R6, a reverse clamping unit 132, a Zener diode D1, a protection diode D2, an upper bridge arm 20, a lower bridge arm 30, a power switch Q2, a load inductor L1, a first power supply BAT1, and a second power supply BAT2. Detailed Implementation
[0037] To better understand the above-mentioned objectives, features, and advantages of this application, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.
[0038] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of this application is not limited to the specific embodiments disclosed below.
[0039] With the development of power electronics technology, silicon carbide (SiC) materials are increasingly widely used in power devices. SiC possesses advantages such as high voltage withstand capability, high frequency, and low loss, making it an ideal material for power electronic equipment. Among them, silicon carbide metal-oxide-semiconductor field-effect transistors (SiC MOSFETs) have become an important component in power electronic circuits due to their high switching speed, low on-resistance, and low thermal resistance.
[0040] SiC MOSFETs are suitable for high-voltage, high-power, and high-frequency applications, making them an ideal choice for high-frequency, high-temperature, and high-power-density power electronic converters (such as home energy storage devices). Compared to traditional Si-based devices, SiC MOSFETs offer lower on-resistance, higher thermal conductivity, and power ratings comparable to Insulated Gate Bipolar Transistors (IGBTs) in terms of static characteristics. In terms of dynamic characteristics, SiC MOSFETs boast faster switching speeds and higher frequency limits, contributing to improved overall power density and efficiency of power electronic devices.
[0041] However, when SiC MOSFETs are used in half-bridge circuits, transient changes in the midpoint potential of the bridge arms create displacement currents through junction capacitance. These currents interact with the parasitic load inductance and gate drive resistance, resulting in voltage spikes. Because SiC MOSFETs have a lower turn-on threshold, positive crosstalk increases the risk of bridge arm shoot-through. Simultaneously, SiC MOSFETs can withstand lower absolute negative turn-off voltages, and negative crosstalk can damage the device. SiC MOSFETs are more sensitive to switching losses. Faster switching speeds result in smaller voltage and current overlap areas and lower switching losses, but under high-frequency drive conditions, increased single-turn-on or turn-off losses can significantly reduce system efficiency, leading to poor heat dissipation and device failure.
[0042] In related technologies, the above problems can be alleviated by optimizing PCB layout and reducing the parasitic load inductance of the loop. However, this solution is highly dependent on the designer's experience. At the same time, further reduction of parasitic parameters requires complex advanced packaging technology, which is expensive. Adding filters, absorption circuits and other means all come at the cost of increasing additional losses and sacrificing system power density. Moreover, repeated trial and error experiments are often required, which greatly reduces R&D efficiency.
[0043] Furthermore, SiC MOSFETs have high switching speeds and high dv / dt ratios, making them prone to gate crosstalk. When the gate crosstalk voltage ΔVgs exceeds the device threshold voltage Vgs(th), there is a risk of false turn-on. In this situation, the SiC MOSFET is easily damaged. Therefore, under many operating conditions, SiC MOSFETs require negative voltage turn-off to ensure system safety. When the upper SiC MOSFET is turned off, the midpoint potential of the bridge arm drops, and the dv / dt ratio is converted into a negative crosstalk voltage at the gate of the lower MOSFET through the Miller effect.
[0044] To address the aforementioned issues, related technologies can suppress and mitigate negative voltage crosstalk by adjusting the turn-on and turn-off resistors of the SiC MOSFET's drive circuit, or by connecting a capacitor in parallel between the gate (G) and source (S) of the SiC MOSFET, thereby ensuring that the negative voltage spike does not exceed the negative voltage spike limit specified in the device datasheet. However, this slows down the normal switching speed of the SiC MOSFET, increases losses, reduces efficiency, and increases heat generation, failing to fully utilize the fast switching characteristics of the SiC MOSFET. Alternatively, a Zener diode can be connected in reverse parallel between the G and S of the SiC MOSFET, but considering the energy of the negative crosstalk voltage, the effect is not significant.
[0045] In view of this, referring to Figures 1-4 below, an embodiment of this application proposes a silicon carbide driving circuit 100. The silicon carbide driving circuit 100 includes multiple driving circuits 10, an upper bridge arm 20 and a lower bridge arm 30 connected to each other. Both the upper bridge arm 20 and the lower bridge arm 30 include a power switch Q2. Each driving circuit 10 is connected to a power switch Q2 and is configured to drive the power switch Q2 to turn on and off. At least one driving circuit 10 includes a driving module 11, a driving resistor R1, a filtering module 12 and a crosstalk suppression module 13.
[0046] The drive module 11 is connected to the gate of the power switch Q2 through the drive resistor R1 and is configured to provide a drive signal to the power switch Q2 to drive the power switch Q2 to turn on and off.
[0047] The filter module 12 is connected to the gate and source of the power switch Q2, and is configured to filter out spike interference between the gate and source of the power switch Q2; and
[0048] The crosstalk suppression module 13 is connected to the gate and source of the power switch Q2, respectively, and is configured to turn on when the power switch Q2 is turned off and the voltage difference between the source and gate of the power switch Q2 is greater than a preset threshold voltage, so as to suppress the negative voltage crosstalk spike generated when the power switch Q2 is turned off.
[0049] In the silicon carbide drive circuit 100 of this application embodiment, the crosstalk suppression module 13 connected in series between the gate and source of the power switch Q2 does not function when the negative crosstalk spike is below a preset threshold voltage. It only activates when the negative voltage spike crosstalk reaches the preset threshold voltage. Compared to related technologies, this suppression measure does not affect the inherent fast switching characteristics of the power switch Q2, ensuring fast switching and reducing its switching losses, thus improving system efficiency and allowing for a smaller drive resistor R1. Furthermore, it solves the crosstalk problem of the drive waveform, reducing the risk of power switch Q2 failure due to excessively high drive negative voltage, lowering the risk of mis-conduction, and improving the quality of the drive waveform. This ensures system safety.
[0050] Specifically, the silicon carbide driving circuit 100 can be applied to silicon carbide devices, with the upper bridge arm 20 and the lower bridge arm 30 interconnected to form a half-bridge circuit. There can be two driving circuits 10: one connected to the upper bridge arm 20 to drive the power switch Q2 of the upper bridge arm 20 to turn on and off, and the other connected to the lower bridge arm 30 to drive the power switch Q2 of the lower bridge arm 30 to turn on and off. The power switch Q2 can be a silicon carbide metal-oxide-semiconductor field-effect transistor (SiC MOSFET), capable of operating at 100kHz to 1MHz, thus enabling high-frequency operation.
[0051] The two drive circuits 10 can be entirely identical or partially identical. For example, in some examples, both drive circuits 10 include a drive module 11, a drive resistor R1, a filter module 12, and a crosstalk suppression module 13. For example, in some examples, one drive circuit 10 includes a drive module 11, a drive resistor R1, and a filter module 12, while the other drive circuit 10 includes a drive module 11, a drive resistor R1, a filter module 12, and a crosstalk suppression module 13.
[0052] In this embodiment, it can be described by taking the two driving circuits 10 as being completely identical, that is, both driving circuits 10 include a driving module 11, a driving resistor R1, a filtering module 12, and a crosstalk suppression module 13 as an example. It can be understood that the two driving circuits 10 are identical. On the one hand, the switching timing and rise / fall time of the power switching transistors Q2 of the upper and lower bridge arms are completely consistent. Strict symmetry can ensure the stability of the resonant frequency, improve the soft switching effect, and avoid the shoot-through risk caused by inconsistent driving. On the other hand, only one driving circuit scheme needs to be developed, which reduces the workload of schematic design, PCB layout and debugging, simplifies the design and reduces costs.
[0053] The drive module 11 can be a drive chip, capable of outputting a drive signal. The output drive signal is transmitted to the gate of the power switch Q2 through the drive resistor R1, thereby driving the power switch Q2 to turn on and off. The drive signal can be a PWM signal; that is, the drive module 11 is used to output a PWM signal to the gate of the power switch Q2, thereby driving the power switch Q2 to turn on and off. For example, the silicon carbide device also includes a controller, which can generate a PWM signal. The drive module 11 is electrically connected to the controller. The drive module 11 is used to amplify and level-convert the PWM signal output by the controller before outputting it to the power switch Q2, thereby meeting the drive requirements of the power switch Q2. Simultaneously, it also ensures electrical isolation between the PWM signal output by the controller and the drive signal of the power switch Q2, reducing interference, meeting safety isolation requirements, and ensuring that the PWM signal and the power switch Q2 are not grounded. Furthermore, the drive circuit also provides power for the drive.
[0054] Furthermore, the power switch Q2 can be an N-type SiC MOSFET, that is, it turns on when the gate voltage Vg of the power switch Q2 exceeds the threshold voltage Vth, and turns off when the gate voltage Vg of the power switch Q2 is lower than the threshold voltage Vth. In other words, when the drive signal output by the drive module 11 is a high-level signal, the power switch Q2 turns on, and when the drive signal output by the drive module 11 is a low-level signal, the power switch Q2 turns off.
[0055] The driving resistor R1 is connected in series between the driving module 11 and the gate of the power switch Q2. It is used to limit the driving current of the driving module 11 and to adjust the turn-on and turn-off rate of the power switch Q2. The value of the driving resistor R1 is not limited and can be determined by comprehensively considering the electrical stress, efficiency, temperature rise, EMC performance, and waveform quality of the driving signal of the silicon carbide device.
[0056] One end of the filter module 12 is electrically connected to the gate of the power switch Q2, and the other end of the filter module 12 is connected to the source of the power switch Q2. This enables the gate (G) and source (S) of the power switch Q2 to maintain a certain level. At the same time, it can filter out the spike interference between the gate and source of the power switch Q2, ensuring the stability of the gate and source (GS) level. Thus, the driving effect of the drive circuit 10 is improved.
[0057] One end of the crosstalk suppression module 13 is electrically connected to the gate of the power switch Q2, and the other end of the crosstalk suppression module 13 is electrically connected to the source of the power switch Q2. The crosstalk suppression module 13 is configured to turn on when the power switch Q2 is turned off, and when the voltage difference between the source and gate of the power switch Q2 is greater than a preset threshold voltage, in order to suppress the negative voltage crosstalk spikes generated when the power switch Q2 is turned off.
[0058] In one example, the drive circuit 10 may include a first drive circuit 101 and a second drive circuit 102, with Q21 as the power switch for the upper bridge arm and Q22 as the power switch for the lower bridge arm. The first drive circuit 101 is connected to the power switch Q21 of the upper bridge arm, and the second drive circuit 102 is electrically connected to the power switch Q22 of the lower bridge arm. When the first drive circuit 101 drives power switch Q21 to conduct, the second drive circuit 102 drives power switch Q22 to turn off; when the first drive circuit 101 drives power switch Q21 to turn off, the second drive circuit 102 drives power switch Q22 to conduct.
[0059] Furthermore, when the drive signal provided by the first drive circuit 101 to the power switch Q21 is high, the filter module 12 filters out high-frequency spike interference from the drive signal, and the difference between the gate (G) and source (S) of the power switch Q21 is positive (Vg > Vs), so the power switch Q21 is turned on, and the crosstalk suppression module 13 is turned off. When the power switch Q21 is turned off, the difference between the gate (G) and source (S) of the power switch Q21 is negative (Vg < Vs), ensuring reliable turn-off of the power switch Q21. At the same time, the midpoint potential of the upper and lower bridge arms decreases, and dv / dt is reduced to a negative crosstalk voltage at the gate of the power switch Q22 through the Miller effect. At this time, if the voltage difference between the source and gate of the power switch Q21 is greater than a preset threshold voltage, the crosstalk suppression module 13 is turned on, thereby suppressing the negative voltage crosstalk spike that occurs when the power switch Q21 is turned off.
[0060] Thus, the drive circuit 10 is configured with a drive module 11, a drive resistor R1, a filter module 12, and a crosstalk suppression module 13. The drive module 11 provides a drive signal to the power switch Q2 and supplies power, thereby driving the power switch Q2 to turn on and off. The drive resistor R1 limits the drive current of the drive module 11 and adjusts the turn-on and turn-off rates of the power switch Q2. The filter module 12 maintains a defined voltage level between the gate and source of the power switch Q2 and filters out sharp spikes between the gate and source of the power switch Q2. To suppress negative voltage crosstalk spikes generated when the power switch Q2 is turned off, the crosstalk suppression module 13 is turned on when the voltage difference between the source and gate of the power switch Q2 is greater than a preset threshold voltage. This allows for rapid switching of the power switch Q2, reducing its switching losses and improving system efficiency. It also reduces the risk of the power switch Q2 failing due to excessively high drive negative voltage, lowers the risk of mis-turn-on, and improves the quality of the drive waveform.
[0061] Referring to Figure 2, in some embodiments, the preset threshold voltage includes a first threshold voltage and a second threshold voltage. The crosstalk suppression module 13 includes a spike absorption unit 131 and a reverse clamping unit 132. The spike absorption unit 131 is connected to the gate and source of the power switch Q2, and is configured to turn off when the power switch Q2 is on, and to turn on when the power switch Q2 is off and the voltage difference between the source and gate of the power switch Q2 is greater than the first threshold voltage to absorb negative voltage crosstalk spikes. The reverse clamping unit 132 is connected to the gate and source of the power switch Q2, and is configured to turn on when the voltage difference between the gate and source of the power switch Q2 is negative and its absolute value is greater than the second threshold voltage to achieve voltage clamping.
[0062] Specifically, the second threshold voltage is greater than the first threshold voltage, and the second threshold voltage is less than the negative voltage spike limit of the power switch Q2. That is, when the difference between the gate voltage and source voltage of the power switch Q2 is negative (Vg < Vs), and the difference between the source voltage and gate voltage of the power switch Q2 is greater than the first threshold voltage but less than or equal to the second threshold voltage, the spike absorption unit 131 is turned on to absorb negative voltage crosstalk spikes, and the reverse clamping unit 132 is turned off. When the difference between the gate voltage and source voltage of the power switch Q2 is negative (Vg < Vs), and the difference between the source voltage and gate voltage of the power switch Q2 is greater than the second threshold voltage, the spike absorption unit 131 is turned on to absorb negative voltage crosstalk spikes, and the reverse clamping unit 132 is turned on to achieve voltage clamping. In this way, the negative voltage spike is controlled within the range defined in the power switch Q2's datasheet, thereby reducing the risk of threshold voltage reduction during long-term use of the power switch Q2.
[0063] Referring further to Figure 2, in some embodiments, the spike absorption unit 131 includes a first voltage divider resistor R3, a second voltage divider resistor R4, an absorption capacitor C2, a switching transistor Q1, and a current-limiting resistor R6. One end of the first voltage divider resistor R3 is connected to the gate of the power switching transistor Q2; one end of the second voltage divider resistor R4 is connected to the other end of the first voltage divider resistor R3, and the other end of the second voltage divider resistor R4 is connected to the source of the power switching transistor Q2; one end of the absorption capacitor C2 is connected to the gate of the power switching transistor Q2; the first terminal of the switching transistor Q1 is connected to the other end of the absorption capacitor C2, and the control terminal of the switching transistor Q1 is connected to one end of the second voltage divider resistor R4; one end of the current-limiting resistor R6 is connected to the second terminal of the switching transistor Q1, and the other end of the current-limiting resistor R6 is connected to the source of the power switching transistor Q2.
[0064] Specifically, the switching transistor Q1 is a transistor, for example, a P-type transistor. When the power switching transistor Q2 is normally turned on, the gate voltage of the power switching transistor Q2 is greater than the source voltage (Vg is greater than Vs). Through the voltage division effect of the first voltage divider resistor R3 and the second voltage divider resistor R4, the switching transistor Q1 is turned off, and the snubber capacitor C2 does not work. When the power switching transistor Q2 is turned off, there is a negative voltage level (Vs is greater than Vg) across the gate and source of the power switching transistor Q2. Through the voltage division effect of the first voltage divider resistor R3 and the second voltage divider resistor R4, the switching transistor Q1 is turned on, and the snubber capacitor C2 starts working. This is equivalent to adding a capacitor across the gate and source of the power switching transistor Q2, which helps to suppress drive crosstalk.
[0065] Thus, by configuring the first voltage divider resistor R3, the second voltage divider resistor R4, the absorption capacitor C2, the switching transistor Q1, and the current-limiting resistor R6, it is ensured that when the power switch Q2 is turned on normally, it will not affect the normal switching. Furthermore, the absorption capacitor C2 only activates when the negative voltage spike crosstalk reaches a certain limit, thus suppressing the negative voltage spike.
[0066] In some embodiments, the reverse clamping unit 132 includes a Zener diode D1 and a protection diode D2, wherein the anode of the Zener diode D1 is connected to the gate of the power switch Q2; the anode of the protection diode D2 is connected to the source of the power switch Q2, and the cathode of the protection diode D2 is connected to the cathode of the Zener diode D1.
[0067] It should be noted that the second threshold voltage is equal to the reverse breakdown voltage of the Zener diode D1. That is, when the negative crosstalk voltage spike reaches a certain value, the protection diode D2 turns on, and the Zener diode D1 breaks down in reverse to absorb the energy of the crosstalk spike. At the same time, it clamps the gate and source voltages of the power switch Q2 to a fixed value, ensuring that the negative voltage spike is controlled within the range defined in the datasheet.
[0068] Thus, by setting the Zener diode D1 and the protection diode D2, it can be ensured that the reverse clamping unit 132 only works when the driving voltage of the power switch Q2 is negative and the MOSFET is turned off.
[0069] In some embodiments, the filter module 12 includes a filter resistor R2 and a filter capacitor C1, which are connected in parallel across the gate and source terminals of the power switch Q2.
[0070] Specifically, the filter resistor R2 and the filter capacitor C1 are connected in parallel to form an RC filter. After the filter resistor R2 and the filter capacitor C1 are connected in parallel, the signal is output from the filter capacitor C1. It allows low-frequency signals to pass through, while having a greater attenuation effect on high-frequency signals. This is because the filter capacitor C1 has a lower impedance to high-frequency signals, and high-frequency signals can more easily flow into ground through the filter capacitor C1. As a result, the spike interference of the gate of the power switch Q2 can be filtered out by the RC filter.
[0071] In this way, by setting the filter resistor R2 and the filter capacitor C1, the gate and source of the power switch Q2 are maintained at a certain level, while the spike interference between the gate and source of the power switch Q2 is filtered out, ensuring the stability of the level between the gate and source of the power switch Q2.
[0072] Please refer further to Figure 2. In some embodiments, the silicon carbide drive circuit 100 further includes a load inductor L1, a first power supply BAT1, and a second power supply BAT2. One end of the load inductor L1 is connected to the positive terminal of the second power supply BAT2, and the other end is connected to the source of the power switch Q2 of the upper bridge arm 20 and the source of the power switch Q2 of the lower bridge arm 30. The drain of the power switch Q2 of the upper bridge arm 20 is connected to the positive terminal of the first power supply BAT1, and the drain of the power switch Q2 of the lower bridge arm 30 is connected to the negative terminals of the first power supply BAT1 and the second power supply BAT2.
[0073] When the driving circuit 10 drives the power switch Q2 of the upper bridge arm 20 to turn on, the power switch Q2 of the lower bridge arm 30 turns off, and the first power supply BAT1, the power switch Q2 of the upper bridge arm 20 and the load inductor L1 form a closed loop (as shown in Figure 3), so that the first power supply BAT1 supplies power to the load inductor L1; when the driving circuit 10 drives the power switch Q2 of the upper bridge arm 20 to turn off, the power switch Q2 of the lower bridge arm 30 turns on, and the second power supply BAT2, the power switch Q2 of the lower bridge arm 30 and the load inductor L1 form a closed loop (as shown in Figure 4).
[0074] In some embodiments of this application, a silicon carbide device is also proposed, which includes the silicon carbide startup circuit 100 of any of the above embodiments.
[0075] In some embodiments of this application, the silicon carbide device 100 can be applied to a home energy storage device, which can be used to power household appliances or electric vehicles, or to store electrical energy.
[0076] In the description of this application, the term "multiple" refers to two or more. Unless otherwise expressly defined, the terms "upper," "lower," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. The terms "connection," "installation," "fixing," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.
[0077] In the description of this application, the terms "one embodiment," "some embodiments," "specific embodiments," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this application, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0078] The above description is merely a preferred embodiment of this application and is not intended to limit 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 protection scope of this application.
Claims
1. A silicon carbide driving circuit (100), characterized in that, The device includes multiple drive circuits (10), an interconnected upper bridge arm (20), and a lower bridge arm (30). Each upper bridge arm (20) and lower bridge arm (30) includes a power switch (Q2). Each drive circuit (10) is connected to one power switch (Q2) and configured to drive the power switch (Q2) to turn on and off. At least one drive circuit (10) includes a drive module (11), a drive resistor (R1), a filter module (12), and a crosstalk suppression module (13). The drive module (11) is connected to the gate of the power switch (Q2) through the drive resistor (R1) and is configured to... The power switch (Q2) provides a drive signal to drive the power switch (Q2) to turn on and off; the filter module (12) is connected to the gate and source of the power switch (Q2) respectively, and is configured to filter out spike interference between the gate and source of the power switch (Q2); and the crosstalk suppression module (13) is connected to the gate and source of the power switch (Q2) respectively, and is configured to turn on when the power switch (Q2) is turned off and the voltage difference between the source and gate of the power switch (Q2) is greater than a preset threshold voltage, so as to suppress the negative voltage crosstalk spike generated when the power switch (Q2) is turned off.
2. The silicon carbide driving circuit (100) according to claim 1, characterized in that, The preset threshold voltage includes a first threshold voltage and a second threshold voltage. The crosstalk suppression module (13) includes: a spike absorption unit (131), which is connected to the gate and source of the power switch (Q2) respectively, and is configured to turn off when the power switch (Q2) is turned on, and to turn on when the power switch (Q2) is turned off and the voltage difference between the source and the gate of the power switch (Q2) is greater than the first threshold voltage to absorb the negative voltage crosstalk spike; and a reverse clamping unit (132), which is connected to the gate and the source of the power switch (Q2) respectively, and is configured to turn on when the voltage difference between the gate and the source of the power switch (Q2) is negative and the absolute value is greater than the second threshold voltage to achieve voltage clamping.
3. The silicon carbide driving circuit (100) according to claim 2, characterized in that, The second threshold voltage is greater than the first threshold voltage, and the second threshold voltage is less than the negative voltage spike limit of the power switch (Q2).
4. The silicon carbide driving circuit (100) according to claim 2 or 3, characterized in that, The spike absorption unit (131) includes: a first voltage divider resistor (R3), one end of which is connected to the gate of the power switch (Q2); a second voltage divider resistor (R4), one end of which is connected to the other end of the first voltage divider resistor (R3), and the other end of which is connected to the source of the power switch (Q2); an absorption capacitor (C2), one end of which is connected to the gate of the power switch (Q2); a switching transistor (Q1), the first terminal of which is connected to the other end of the absorption capacitor (C2), and the control terminal of which is connected to one end of the second voltage divider resistor (R4); and a current limiting resistor (R6), one end of which is connected to the second terminal of the switching transistor (Q1), and the other end of which is connected to the source of the power switch (Q2).
5. The silicon carbide driving circuit (100) according to claim 4, characterized in that, The switching transistor (Q1) is a triode.
6. The silicon carbide driving circuit (100) according to claim 2, characterized in that, The reverse clamping unit (132) includes: a Zener diode (D1), the positive terminal of which is connected to the gate of the power switch (Q2); and a protection diode (D2), the positive terminal of which is connected to the source of the power switch (Q2), and the negative terminal of which is connected to the negative terminal of the Zener diode (D1).
7. The silicon carbide driving circuit (100) according to claim 1, characterized in that, The filtering module (12) includes a filtering resistor (R2) and a filtering capacitor (C1), which are connected in parallel across the gate and source terminals of the power switch (Q2).
8. The silicon carbide driving circuit (100) according to claim 1, characterized in that, The power switch (Q2) includes a SiC MOSFET.
9. The silicon carbide driving circuit (100) according to claim 1, characterized in that, The silicon carbide driving circuit (100) further includes a load inductor (L1), a first power supply (BAT1), and a second power supply (BAT2); one end of the load inductor (L1) is connected to the positive terminal of the second power supply (BAT2), and the other end is connected to the source of the power switch (Q2) of the upper bridge arm (20) and the source of the power switch (Q2) of the lower bridge arm (30); the drain of the power switch (Q2) of the upper bridge arm is connected to the positive terminal of the first power supply (BAT1), and the drain of the power switch (Q2) of the lower bridge arm (30) is connected to the negative terminals of the first power supply (BAT1) and the second power supply (BAT2).
10. A silicon carbide device, characterized in that, Includes the silicon carbide drive circuit (100) according to any one of claims 1-9.