Patent ID: 8800738

Claim:
A wireless power feeder that feeds power from a feeding coil to a receiving coil by wireless using a magnetic field resonance phenomenon between the feeding coil and receiving coil, said feeder comprising: a capacitor; a plurality of the feeding coils; a plurality of receivers that are provided respectively in correspondence with the plurality of feeding coils and each receives a position signal from a receiving body having the receiving coil; a power transmission control circuit that supplies AC power at a drive frequency to the feeding coil corresponding to the receiver that has received the position signal to allow the feeding coil to feed AC power to the receiving coil; and a selection circuit for selecting a receiver from the plurality of receivers, the selection circuit including a plurality of photodiodes, wherein an input of each of the plurality of photodiodes is connected to a corresponding receiver of the plurality of receivers, wherein an output of each of the plurality of photodiodes is connected to a common line, wherein the power transmission control circuit supplies the AC power to the feeding coil corresponding to the selected receiver, wherein any one of the feeding coils is selectively connected to the capacitor, the selected feeding coil and the capacitor resonate at a resonance frequency, and the power transmission control circuit adjusts the drive frequency to the resonance frequency.