Reducing Crosstalk of SiC MOSFET Gate Driver using a Negative Driving Voltage

This study examines the enhancement of reliability in Silicon Carbide (SiC) MOSFETs in a half-bridge configuration through the use of an Active Gate Driver (AGD). SiC MOSFETs offer higher efficiency, power density, and reliability compared to Silicon (Si) MOSFETs due to their wider band gap, faster electron mobility, and better thermal conductivity. However, SiC MOSFETs suffer challenges such as high dv/dt and di/dt, oscillation, ringing, leading to Electromagnetic Interference (EMI), and voltage overshoot, as well as crosstalk that disrupts control signals and MOSFET stability. To address these issues, an AGD with a negative voltage technique (NVTAGD) was designed to suppress crosstalk effects and reduce shoot-through without requiring an additional negative power supply. Test results indicate that the AGD significantly reduces voltage overshoot by 6.97 V or 21.02 dB compared to a Conventional Gate Driver (CGD). Also, it suppresses positive crosstalk by 1.019 V or 9.59 dB and negative crosstalk by 1.69 V or 12.19 dB, maintaining the stability of the gate-source voltage (VgsH). Although the AGD has a longer rise time compared to the CGD, this increase is considered a reasonable trade-off for crosstalk suppression. Drain current (Id) waveforms indicate no sudden current spikes, suggesting no shoot-through occurrence with the AGD. In conclusion, the AGD outperforms in enhancing MOSFET reliability by reducing overshoot and crosstalk, despite a slight increase in rise time that may contribute to switching losses.