Vertically Stacked Dual-Bus DC-DC Converter for Data Center High-Current Power Delivery

Increasing power consumption in data centers is pushing the DC distribution networks system for high efficiency and power density, redundancy, and low-cost design. To comply with this trend, this paper presents a dual-bus 48 V to 12/4 V back-to-back converter for high-current power delivery in data centers, designed with a vertical assembling structure. This converter is realized with a modular approach consisting of a four-phase interleaved buck converter cascaded with a switched capacitor voltage selector. The four buck converters are connected in parallel and use an interleaved control modulation to distribute the current, providing a stable voltage to the switched capacitor converter in the second stage. Four MOSFETs are paralleled in each leg of the switched capacitor converter to withstand the high output current. The architecture has high modularity and scalability ensuring low voltage drop and redundant operations. A vertically stacked prototype with a 200 A maximum output current is tested and discussed in this paper. A small equivalent output resistance of 0.34 mΩ, reduced cost of 0.82 /A, and DOE Level VI efficiency compliance has been achieved.