Topology and Magnetics Integrated Design for Switched-Capacitor $LLC$Hybrid 48 V–1 V DCX in Data Center Applications

The magnetic design of dc transformer (DCX) plays a critical role in achieving high efficiency and power density in datacenter applications requiring high voltage conversion ratios and high output currents. Hybrid switched-capacitor and transformer-based topologies are particularly suitable for such applications, owing to simplified transformer design with reduced turns ratio. This manuscript proposes a novel hybrid DCX topology that merges the resonant tanks of the switched-capacitor cell and the transformer-based cell by current-loop coupling. Additionally, a dual leakage-inductance transformer model is developed to facilitate the heterogeneous magnetic integration. A matrix transformer with integrated synchronous rectifiers (SRs) and output capacitors is designed to support high-load currents and enhance power density. A 1MHz, 48 V–1 V/150 A prototype is constructed based on the proposed DCX topology and a 12:1 dual leakage-inductance transformer. Experimental results well validate the concept, demonstrating a peak efficiency of 93.8%.