Analysis and design of clamped-mode resonant converters withvariable load

In this paper, a design procedure for clamped-mode resonant converters working with variable load is proposed and analyzed. The operation of these converters with general parallel or series loads is reviewed first. The operation of the transistors as zero-voltage switches is identified and characterized as mode A. Mode A is preferred to simplify the implementation of the power switches and to increment the converter efficiency. As a case study, the design of an RF power amplifier is presented. The amplifier is connected to a variable load with reactive characteristics, through a low-pass filter of three elements. The validity of the proposed design approach is verified with an experimental setup.