A High-Ratio and High-Current DCX with Vertical Duplex Matrix Transformer

In response to the challenges posed by power-hungry processors, this work presents the design of a high step-down ratio DC transformer (DCX) with very high output current. The resonant topology, commonly known as LLC, is selected for the DCX converter. Initially, the circuit design considerations are revisited to gain a deeper understanding of the challenges in this application. The impacts of converter's input capacitance, output capacitance, and additional secondary leakage inductance are analyzed in detail, revealing their significant effects on the resonant point. As a central element in the DCX, the design of Vertical Duplex Matrix Transformer is proposed and described in detail. The core and winding loss model of the transformer is built to generate the performance space. Furthermore, multiple winding interleaving structures are also analyzed. Finally, a prototype is constructed, achieving an efficiency of 88.6% at the continuous full load of 488 A, with a 48-to-1 step-down ratio. The peak efficiency is 91.3%, achieved at 190 A output. This DCX design offers a full transformer-based solution, delivering the highest gain and output current to date.