Real-time programmable VR for power delivery efficiency enhancement

The typical VR for server CPU or memory is multi-phase with constant switching frequency and drive voltage. This only provides the best VR efficiency in certain load ranges. In this paper, we will introduce a new VR technology. This technology attempts to enhance the VR power efficiency and reduce the power loss through programming the digital VR with different VR factors (phase counts, switching frequencies and drive voltages) when the CPU and memory load varies. The efficiency improvement and power savings of the new technology were tested on one server board. Using this methodology, over 7.2W of CPU VR power loss was saved when the board operates under certain load conditions.