Evaluation of gallium nitride transistors in high frequency resonant and soft-switching DC-DC converters

The emergence of gallium nitride (GaN) based power devices offers the potential to achieve higher efficiencies and higher switching frequencies than possible with aging silicon (Si) power MOSFETs. In this paper, we will evaluate the ability of gallium nitride transistors to improve efficiency and output power density in high frequency resonant and soft-switching applications. To experimentally verify the benefits of replacing Si MOSFETs with enhancement mode GaN transistors (eGaN^®FETs) in a high frequency resonant converter, 48 V to 12 V unregulated isolated bus converter prototypes operating at a switching frequency of 1.2 MHz and an output power of up to 400W are compared using Si and GaN power devices.