Power efficiency analysis of a multi-oscillated current resonant type DC-DC converter

This paper deals with an analysis of the power efficiency of a multi-oscillated current resonant type DC-DC converter. The current resonant type converter employs generally the pulse frequency modulation. For this reason, the magnetizing current through the converter causes not only a power loss under a light load, but also a loss during stand-by. In order to solve these problems, a multi-oscillated current resonant type DC-DC converter has been proposed, and revealed the advantage of its control method which can reduce power loss under light load and keep low switching noise. An analytical relationship of among states, operating mode and efficiency characteristics of this converter are defined. As a result, it was confirmed that for this converter, the output power depends on the voltage of resonant capacitor, and consequently, it is important to determine constants of resonant capacitor and inductance of transformer. The maximum efficiency is 95.4% with the magnetizing inductance 1.8 mH.