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.