A Zero Inductor-Voltage 48V to 12V/70A Converter for Data Centers with 99.1% Peak Efficiency and 2.5kW/in3 Power Density

Abstract

The demand for internet and computing resources has led to datacenters and servers being one of the fastest growing consumers of power in the world today. While datacenter power architectures have improved over time, the majority of the loss still occurs at the server power supply, and board level voltage regulators. To attempt to improve this, Google has proposed and implemented a 48 volt server architecture that can significantly reduce both the upstream conversion losses, and the distribution losses within the server racks. Google has estimated that this change can reduce their overall conversion losses by up to 30%, but to fully realize these benefits new technology is needed to convert 48 volts down to the point of load voltage levels. The Intermediate Bus Architecture, where a steps down the 48 volts to a lower bus voltage which is then stepped down by point-of-load regulators is a very attractive option to bridge the gap between the 48 volt architecture of cutting edge servers, and the existing 12 volt architecture. The proposed topology is a novel intermediate bus converter that can achieve up to 2500W/in3 power density, 99.1% peak efficiency, and 97.2% full load efficiency for 70A 12V output. Compared with other cutting edge designs this work achieves higher efficiency, and superior power density without the need for complex control, or a sensitive resonant based design.