A novel Non-Isolated Two-Phase Full Bridge topology for VRM applications

In this paper a new full bridge topology called the two-phase non-isolated full bridge (NFB) is introduced. The proposed two-phase NFB can handle the same power as two parallel one-phase NFBs, but with less MOSFETs, better efficiency and lower cost. To demonstrate the advantages of the new topology, two prototypes are built on a 12 layer 2 oz PCB board, one with four inductors, the other with three inductors. Two prototypes achieve 82.3% & 82% efficiency at 1 MHz full load (1V/80A) respectively. This is compared to 81.8% efficiency of the two paralleled one-phase NFBs. At light load (1V/10A), a 4% efficiency improvement is achieved. Experimental results demonstrate that compared with two paralleled one-phase NFBs the two-phase NFB is able to achieve better efficiency with a simplified power train circuit and reduced cost.