Comparative Evaluation of Transformer-based Fixed-ratio DC-DC Converters for 48V Data Centers

Transformer-based fixed-ratio DC-DC converters are widely used in 48V data centers to perform voltage step-down. This paper aims to conduct a comparative evaluation of various topologies in terms of operation principles, voltage conversion ratios, current and voltage stress, and practical design considerations. Based on 4: 1 intermediate bus architecture, we selected an optimal topology and developed a 1kW 4: 1 bus converter with superior 98.2% efficiency and 5.4kW/in3 power density. This prototype is configured into a system board equipped with multi-phase voltage regulators (VRs) capable of delivering kilo-amperes current and providing fast transient response for AI computing cores.