Impact of the Dynamic On-State Resistance Increase in a Phase-Shifted GaN Low Voltage Converter

Abstract:
In a phase-shifted converter applying low voltage normally-off GaN transistors, the dynamic on-state resistance shows a marginally increasing value at low currents but increases unexpectedly at higher currents. Since the converter is designed for a high current application, the observed Ron-degradation has a particular negative effect on the achievable output power and efficiency. This paper investigates the influence of the increased on-state resistance in continuous half-bridge operation and in the phase-shifted full-bridge converter. In order to show the ongoing improvements in GaN device technology, double-pulse and continuous investigations are conducted with transistors from different production lots.