Bi-lateral Energy Resonant Converter (BERC) with Merged Two-Stage Inductor for 48-to-12V Applications

Abstract

Resonant switched capacitor (ReSC) based converters are enticing with their high performance in high- and fixed-ratio applications, due to their efficient utilization of both active semiconductors and passive components. This paper proposes a bi-lateral energy resonant converter (BERC), that further improves the passive utilization by merging the inductors in two adjacent cascaded stages without additional components and switch stress; therefore, yielding simultaneously high efficiency and very compact size. The proposed BERC features a new current-type ReSC and comprises an interleaving technique that relocates the output inductor to the input for step-down applications, providing more design freedom when cascading multiple stages and allocating passive devices. To demonstrate the concept, a 48-to-12 V converter prototype, with a very small volume of 0.184 in3, is implemented. The prototype is tested up to 50 A, thus achieving an excellent power density of 3200 W/in3. Meanwhile, a peak efficiency of 98.9% is achieved by realizing a zero voltage switching (ZVS) technique designed for BERC.