Coupled-Transformer Voltage Regulator With Integrated Magnetics and High Power Density

This article proposes a high-power-density flux-split coupled-transformer voltage regulator (FS-CTVR) with improved dynamic response for 48 V data center power supplies. The topology resolves the large winding loss and insufficient dynamic performance of convenitional current Doubler rectifier (CDR) converters. A magnetically integrated transformer with primary flux splitting and secondary parallel current sharing is developed to achieve a high turns ratio, reduce winding footprint and current stress, and mitigate winding losses. Additional PCB winding layers form a common coupling loop for multiphase CDR transformers, which reduces transient output inductance and improves dynamic response. Comprehensive analysis, design and performance evaluation of the FS-CTVR are presented. A two-module parallel prototype (54 V input, 0.9 V output) is built and tested. Each module delivers 150 A full-load current, 88.6% full-load efficiency and 1687 W/in³ power density, with a dynamic voltage fluctuation of 88 mV. Experimental results validate the feasibility and superior performance of the proposed topology.