A comparison of half-bridge resonant converter topologies

The half-bridge series resonant, parallel resonant and combination series-parallel resonant converters are compared for use in low output voltage power supply applications. It is shown that the combination series-parallel converter, which takes on the desirable characteristics of the pure series and the pure parallel converter, removes the main disadvantages of those two converters. Analyses and breadboard results show that the combination series-parallel converter can run over a large input voltage range and a large load range (no-load to full-load) while while maintaining excellent efficiency. A useful analysis technique based on classical ac complex analysis is also introduced.