A 20MHz-Transformer-Based Isolated Gate Driver for 3.3kV SiC MOSFETs

This paper presents a 20MHz-transformer-based isolated gate driver (GD) for 3.3kV SiC MOSFETs. The proposed GD transmits PWM signal and gate-drive power simultaneously through 20MHz very-high-frequency (VHF) modulated resonant flyback converters (RFCs). A PCB-based air-core transformer is designed to meet the insulation voltage of 15kVrms and achieve a low coupling capacitance of 5pF, which enhances the noise immunity to high dv/dt of 3.3kV SiC MOSFETs. The proposed GD does not require additional isolated GD power supplies nor optical fibers and can operate within the full PWM duty-cycle range. Experimental results on 3.3kV discrete SiC MOSFETs are provided to validate the effectiveness of proposed GD.