LOAD RESONANT CONVERTERS

摘要

A load resonant converter (1) comprises a resonant circuit (3) having a plurality of resonant frequencies when connected to a load RLOAD and different apparent resistances at at least two of its resonant frequencies, and a controller (5) serves to control the resonant circuit (3) so as to provide an output corresponding to a first impedance transformation when the resonant circuit (3) is caused to resonate at a first resonant frequency and so as to provide an output corresponding to a second impedance transformation when the resonant circuit (3) is caused to resonate at a second resonant frequency. Such a load resonant converter (1) may be controlled so as to provide two or more distinct output power levels, or alternatively so as to provide output power levels within a predetermined acceptable range when connected to a variable load by switching the operating frequency of the circuit between two or more resonant frequency values in dependence on the load voltage.