Analysis of a Novel Current Resonant DC-DC Converter

This paper presents a novel current-resonant-type dc-dc converter. In general, the current-resonant-type converters have several remarkable features such as high efficiency, small size, low cost, and low noise and are often used in many electronic systems such as personal computers, flat-panel displays, and so forth. The current-resonant-type converters commonly employ the pulse frequency modulation for the regulation of the output voltage, and their magnetizing inductance is set relatively small. For this reason, the magnetizing current through the converter causes nonnegligible power losses under not only the light load but also standby conditions. Therefore, power supply systems using this type of converter have a problem in which the required smaller size is not able to be achieved because an auxiliary converter is necessary for the standby operation. In order to solve this problem, a novel current resonant converter has been proposed, in which two driving methods are employed. In these driving methods, the high-side MOSFET, as one of two main switches, is driven by an auxiliary winding of the transformer; and the low-side MOSFET, as another main switch, is driven by the driving integrated circuit with a low withstand voltage. As a result, it is clarified that the output voltage regulation is performed well in the useful operation modes. The maximum efficiency is 95.4% at the rated output power.