A Comparison of Multilevel "Zero Inductor-Voltage" Converters for Data Center Applications

Abstract

Datacenter power architectures have improved over time, but the majority of the loss still occurs at the server power supply and board level voltage regulators. Google has proposed and implemented a 48 volt server architecture that can reduce their overall conversion losses by up to 30%, but to fully realize these benefits new technology is needed to converter 48 volts down to the point of load voltage levels. The Intermediate Bus Architecture 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 family of converters presented in this paper are intermediate bus converters that have demonstrated up to 990W/in3 power density, and higher than 99% peak efficiency for 48V to 12V conversion. Compared with other cutting edge designs this family of converters achieves high power density and efficiency without the need for complex control, or a sensitive resonant based design. This is achieved through low reliance on magnetic components, without the drawbacks traditionally associated with switched capacitor topologies.