Innovative application and driving of enhancement mode gallium nitride power transistors

Abstract

Wide-bandgap semiconductors like Gallium Nitride (GaN) are enabling higher efficiency and greater power density in power electronics. The objective of this work is to develop novel gate drive methods and applications for the proliferation of Enhancement mode (E-mode) GaN power transistors. The challenges of driving enhancement mode GaN devices are identified. Gate drive study is conducted to review the advantages and limitations of various gate drive methods. A 2-stage gate drive is introduced to allow a capacitor-less type gate drive to meet the requirements of the GaN GIT. This is further improved by proposing a 2-stage, 2-phase gate driver to reduce the gate ringing. Simulation is conducted to verify the design and the proposed design demonstrates reduction in gate ringing. A GaN GIT gate driver IC is evaluated against the R-type and RC-type gate driver to demonstrate driving the GaN Gate Injection Transistor (GIT) at high slew rates (~150 V/ns) while having built-in active Miller clamp and self-generated negative voltage rail for cross-conduction protection. This research investigated the application of GaN GIT in Inductive Power Transfer (IPT) for Electric Vehicles (EV). IPT systems provide significant benefits over conventional plug-in chargers. A high frequency inverter using GaN GIT, which have low on-resistance and gate charge, is implemented to