A transformerless dual active half-bridge DC-DC converter for point-of-load power supplies

Point-of-load (POL) power supplies contribute significantly to the overall volume, weight, and cost of many electronic devices. This is mainly due to the fairly large inductor of the buck converter commonly used in these applications, which causes it to have a relatively low power density. The goal of this paper is to propose an alternative converter for POL applications which uses a much smaller inductor. The proposed converter, referred to as a transformerless dual active half-bridge (DAHB), uses an ac-link to transfer power, instead of the more conventional dc-link. Not only does the transformerless DAHB offer a significant reduction in the volume of the bulky inductor, but it also allows soft switching and 50% duty cycle operation of all active devices. The advantages of the proposed converter have been verified with a 12 V to 3.3 V, 10 A, 0.3 MHz to 1 MHz experimental prototype. The results demonstrate a reduction of approximately 50% in the volume of reactive components, while maintaining high power processing efficiency.