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.