D03.8 - Magnetics Integrated Design for CNR Point-of-Load Converter

In data center point-of-load applications, current ninefold rectifier (CNR) converter offers obvious advantages over conventional current doubler rectifier (CDR), including zero-voltage switching (ZVS) and enhanced output current capability. However, the CNR typically employs three discrete transformers, resulting in a bulky design that compromises power density. Given the demanding requirements of data centers — particularly large voltage conversion ratios and high output currents — efficient magnetic design is crucial for achieving both high efficiency and high power density. To address this challenge, this paper presents a magnetic integration scheme tailored for the CNR converter, which substantially reduces transformer core volume. A 24 V-to-0.8 V, 180 A, 500 kHz CNR prototype incorporating the integrated magnetics is designed and experimentally validated. The prototype demonstrates a peak efficiency of 93.7% and maintains 89.6% efficiency at full load.