Capacitor-Less Gate Drive Circuit Capable of High-Efficiency Operation for Non-Insulating-Gate GaN FETs

Abstract

Recently, Gallium Nitride (GaN) power devices have become very attractive because of their high power density. GaN FETs, however, differ from MOSFETs, and it is possible that GaN-based power electronics circuits show lower efficiency than Si-based circuits because of their unique characteristics. A capacitor-less gate drive circuit is proposed as a solution. This paper shows the effectiveness of a capacitor-less gate circuit in terms of gate drive loss, reverse conduction loss, and recovery loss, and compares it with capacitor-type gate drive circuits for GaN FETs. Drive loss analysis of an inverted gate drive circuit showing the lowest losses among capacitor-type gate drive circuits and a capacitor-less gate drive circuit was made to examine the differences between them. The results show that higher efficiency operation is obtained by applying a capacitor-less gate drive circuit to simple test circuits.