A novel asymmetrical-pulse-width-modulated CLL resonant converter with improved efficiency

In this paper, a novel circuit configuration is presented as an attractive option for point-of-use power supplies (PUPS) used in telecom applications. A CLL resonant tank is used to guarantee zero voltage switching (ZVS) for the entire working range. The proposed circuit arrangement offers an extended input voltage range of 35 V-75 V; while significantly reducing the associated conduction loss to improve the overall efficiency. Proper resonant tank design will ensure efficient operation over the entire working range by maintaining zero voltage switching for all line and load conditions, as well as minimizing conduction loss by decreasing circulating current commensurate with load. The design steps for a 25 W, 48 V/2.5 V converter are given in a detailed analysis. SIMetrix simulation results are presented to validate the proof-of-concept design and to highlight the merits of the proposed topology.