Improving Performance of High Speed GaN Transistors Operating in Parallel for High Current Applications

The emergence of gallium nitride (GaN) based power devices offers the potential to achieve higher efficiencies and higher switching frequencies than possible with silicon (Si) power MOSFETs. In this paper, we will evaluate the ability to parallel high speed GaN transistors in applications requiring higher output current. The impact of in-circuit parasitics on performance will be assessed and a PCB layout technique will be proposed to improve the performance of high speed GaN transistors operating in parallel. 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.