Self-Oscillating Very High Frequency Inverter for Gate Driver Power Supply

Abstract:
High side gate drivers are today supplied either by a bootstrap circuit or transformers with potential separation. With switching speed generated by WBG semiconductors both come to a limit, the boots trap diode due to its revers recovery and capacitance, the transformer due to its coupling capacitance between primary and secondary. This paper introduces an alternative way of supplying gate drivers with the potential to miniaturize them further than possible today. It is based on a VHF self resonating circuit (76 MHz) and a potential separation via a 1 pF high voltage capacitor. This low capacitance value is sufficient to supply the driver with up to 35 mW.