Analysis and design of clamped-mode resonant converters with variable load

In this paper, a design procedure for clamped-mode resonant converters work ing with variable load is proposed and analyzed. The operation of these con verters with general parallel or series loads is reviewed first. The operat ion of the transistors as zero-voltage switches is identified and character ized as mode A. Mode A is preferred to simplify the implementation of the p ower switches and to increment the converter efficiency. As a case study, t he design of an RF power amplifier is presented. The amplifier is connected to a variable load with reactive characteristics, through a low-pass filte r of three elements. The validity of the proposed design approach is verifi ed with an experimental setup.