System Optimization of a High Power Density Non-Isolated Intermediate Bus Converter for 48 V Server Applications

With the power architecture transition from a 12 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 analyze system optimization for a 48–12 V non-isolated, fully regulated, intermediate bus converter (IBC) to maximize efficiency and power density. This includes detailed analyses on the impact of power semiconductor device, gate driver as well as an exhaustive treatise on the choice of the optimal inductor. The final experimental prototype, a fully regulated, digitally controlled, 720 W, five phase, GaN transistor-based 48–12 V buck IBC demonstrates exceptional efficiency and power density, respectively, exceeding 95% and 1000 W/in
³
.