SiC MOSFETs Gate Driver With Minimum Propagation Delay Time and Auxiliary Power Supply With Wide Input Voltage Range for High-Temperature Applications

Abstract

Low propagation delay time is essential for SiC drivers at high frequency. The propagation delay time of the commercial parts is normally over 100 ns. A signal isolation circuit and a level shifting circuit are proposed and applied in SiC drivers with minimum propagation delay time. The narrow edge signals of the input pulsewidth modulation (PWM) signal are extracted by nondelay RC differential circuits in the control side and demodulated by an RS flip-flop in the drive side so that only two low-profile transformers are used for low-delay signal isolation. A two-stage isolated auxiliary power supply without linear optocouplers is proposed in order to realize wide input voltage range and wide operation temperature range. Wide input voltage range is achieved by forward- feedback control. The experimental results verify the proposed driver advantages. The propagation delay time at 400 kHz is 49.6 ns for the rising edge and 18.4 ns for the falling edge, which are reduced by over 50% compared with the commercial parts. The prototype is tested under the ambient temperature of 85 °C with the 9–18-V input auxiliary power supply. Considering the temperature rise of 28 °C, the operation temperature of the power supply is 113 °C.