A novel circuit for non-contact charging through electro-magnetic coupling

A DC-to-DC power converter suitable for noncontact charging a rechargeable cell using electromagnetic coupling is presented. The circuit is a self-oscillated class C DC-to-DC power converter, for reducing the switching loss and the core loss of the transformer. Zero voltage switching is realized by a resonance of the parasitic parameters of the transformer. Through electromagnetic coupling using this class C converter, a noncontact battery charger of 86% efficiency has been achieved, under input and output voltages of 140 V and 6 V, respectively.<>