A series-stacked power delivery architecture with hot-swapping for high-efficiency data centers

Current data center power delivery architectures consist of many cascaded power stages, where the system-level efficiency is dependent on the efficiency of the power elements. Recently, series-stacked power delivery architectures eliminated this dependency and reported more than 99% system-level power conversion efficiencies for data centers. In this paper, we address the important start-up and hot-swapping challenge of the series-stacked power delivery architectures without sacrificing the high power delivery efficiency. We experimentally validate the hot-swapping operation on a testbed that includes four series-connected 12 V, 65 W servers and four differential converters. The results show that the continuous operation of the series-stacked servers can be maintained, while one of the servers is hot-swapped.