Patent ID: 7119311

Claim:
An induction circuit for a contactless power supply apparatus including an induction coil for inducing a current in response to a high frequency current flowing through a primary induction circuit to transfer the inductive energy of the primary induction circuit to a load, the induction circuit comprising: a resonant capacitor coupled in parallel with the induction coil, forming a resonant circuit with the induction coil, wherein the resonant circuit has a resonant frequency the same as the frequency of the high frequency current in the primary induction circuit; a full-wave rectifier comprising four diodes wherein two of the diodes have coupled cathodes and the other two diodes have coupled anodes, for rectifying an alternating current(AC) generated by the resonant circuit and supplying the AC current to the load; two short-circuited units coupled in parallel to the two diodes which have coupled cathodes in the full-wave rectifier respectively; a current-limiting coil coupled between the output of the full-wave rectifier and the load; and a smoothing capacitor coupled in parallel with the load and coupled between the current-limiting coil and the load; wherein the resonance of the resonant circuit stops when only one of the short-circuited units is turned on.