Patent ID: 8669677

Claim:
A wireless power feeder which performs power feed by a non-contact method to a wireless power receiver having a power receive resonance circuit including a power receive coil and a power receive capacitor, the wireless power feeder comprising: a power feed coil; a resonance current detector which detects a resonance current of the power receive resonance circuit; and a control circuit which performs power feed from the power feed coil to the power receive coil, on the basis of a magnetic field resonance effect between the power feed coil and the power receive coil, by supplying AC current to the power feed coil, and which associates a frequency of the AC current with a frequency of the resonance current detected by the resonance current detector, wherein the power feed coil does not substantially constitute a resonance circuit; the resonance current detector has a detection resonance circuit which includes a detection coil and a detection capacitor, and detects a resonance current of the power receive resonance circuit on the basis of a magnetic field resonance effect between the detection coil and the power receive coil; a winding region of the detection coil in the resonance current detector is smaller than a winding region of the power feed coil; and the detection coil in the resonance current detector is disposed such that a central winding axis of the detection coil forms an angle of not less than 80° and not more than 100° with respect to magnetic field vectors generated by the power feed coil.