GaN Power Converters

Demonstrating the potential of our GaN power-switching transistors is one of the targets of the Joint Lab Power Electronics that is run jointly by Technische Universität Berlin and FBH.

GaN-Based 1 kW DC-DC Converter

Operation of a diode-less 1 kW half-bridge DC buck-converter with two 75 mOhm GaN transistors from FBH. Left: 300 V switching transients at 250 kHz and current in the inductive load. Right: Power loss as function of transmitted power and switching frequency.

In this framework, a half-bridge based DC-DC buck converter using two 75 mOhm FBH transistors has been designed and put into operation. This converter utilizes the GaN transistor's backward conduction path and any separate free-wheeling diodes can be omitted.

The converter was operated at 300 V with 250 kHz switching frequency and the losses were estimated by calorimetric methods. An efficiency of 97.3% was demonstrated for 800 W output power and 250 kHz switching frequency. The efficiency increased to 98.1% for 125 kHz switching frequency.