Patent ID: 8669678
Filing Date: 2014-03-11
Classification: H02J

Abstract:
1. A wireless power feeder which performs power feed by a non-contact method to a wireless power receiver having a power receive coil, the wireless power feeder comprising: a power feed coil; and a control circuit which performs power feed from the power feed coil to the power receive coil on the basis of magnetic coupling 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 current flowing in the power receive coil, wherein the control circuit has: a phase delay circuit which generates a delayed AC voltage in which the phase of an output AC voltage is delayed; a magnetic sensor which is biased by the delayed AC voltage and detects a magnetic field generated by the power receive coil; a phase detection circuit which generates a phase difference instruction voltage corresponding to a phase difference between an output voltage from the magnetic sensor and a comparison voltage, on the basis of the output voltage and the comparison voltage; and an AC current generation circuit which generates the output AC voltage having a frequency based on the phase difference instruction voltage, and generates the AC current having a frequency corresponding to the frequency of the output AC voltage, wherein the control circuit further has a plurality of magnetic sensors and an adder which adds up output signals from the plurality of magnetic sensors; and the phase detection circuit generates a phase difference instruction voltage corresponding to a phase difference between an output voltage from the adder and a comparison voltage, on the basis of the output voltage and the comparison voltage.