Effectively paralleling gallium nitride transistors for high current and high frequency applications

Gallium nitride (GaN) based power devices are rapidly being adopted due to their ability to operate at frequencies and switching speeds beyond the capability of silicon (Si) power MOSFETs. In this paper, we will discuss paralleling high speed GaN transistors in applications requiring higher output current. This work will discuss the impact of in-circuit parasitics on performance and propose printed circuit board (PCB) layout methods to improve parallel performance of high speed GaN transistors. Four parallel half bridges in an optimized layout operated as a 48 V to 12 V, 480 W, 300 kHz, 40 A single phase buck converter achieving efficiencies above 96.5% from 35% to 100% load will be demonstrated. Also in this paper, we will discuss the latest eGaN® FET developments including the fourth generation devices designed for higher current handling capability.