Multi-Frequency Trans-Inductor Voltage Regulator

The cloud computing revolution has led to a rapid increase in data center electricity consumption. Low-profile, high-density server boards are needed to efficiently step down the input distribution bus to the digital rails as power demands rise. Intermediate Bus Converters (IBCs) typically use soft-switching resonant topologies like non-regulated LLCs, while the core voltage is regulated using a multiphase buck VRM. A classic VRM must guarantee digital load regulation and represent the least efficient element of the energy distribution chain. High transient performances require high switching frequencies, which decrease the efficiency of the VRM. This paper describes a multi-frequency conversion system based on a trans-inductor structure for multiphase voltage regulator modules (VRM) to obtain a higher efficiency without affecting transient performances. Experimental results of a 16-phases prototype show the effectiveness of the proposed approach.