A 48-to-1V LLC DC Transformer

This paper presents the design and testing of an LLC DC transformer (DCX) capable of directly converting power from a regulated 48 V DC bus to the point of loads (PoLs). By using series connected transformer windings and parallel connected rectifiers, the proposed LLC DCX has achieved high voltage conversion ratio (48:1) and high output current (>300A) within a 58 by 15 by 5.6 mm volume. The design of the high-frequency transformer is introduced and a 48-to-IV DCX prototype with 300A output current is constructed, exhibiting a peak efficiency of 93.7% and a full load efficiency of 89.0%.