A study on the self turn-on phenomenon of power MOSFET induced by the turn-off operation of body diodes

Abstract

SiC power devices generally operate with fast switching. The fast switching operation in power conversion circuits suffer from the self turn-on phenomenon of a power MOSFET in which the gate voltage is induced to fluctuate by the turn-on operation of the MOSFET on the other side in the bridge circuit. The self turn-on results in a large power loss, when the fluctuating gate voltage exceeds the threshold gate voltage. This paper analytically discusses the self turn-on phenomenon of the MOSFET related to the turn-off operation of its body diode, which is initiated by the turn-on operation of the MOSFET on the other side in the bridge. This analysis was evaluated experimentally.