GaN Based Multilevel Intermediate Bus Converter for 48 V Server Applications

With the power architecture transition from a 12 V to 48 V rack in modern data centers there is an increased interest in improving 48 V power conversion efficiency and power density. In this paper, we will explore system optimization of 48 V to 12 V non-isolated, fully regulated, intermediate bus converters (IBC) to maximize efficiency and power density. Two final GaN transistor based experimental prototypes, a traditional buck converter and a three level switched capacitor buck converter are compared, with the three level converter providing a 50% reduction in inductor volume and a 25% reduction in overall converter power loss.