Patent ID: 9490651
Filing Date: 2016-11-08
CPC Classification: H02J,H02M,H04B

Claim Text:
1. A power transmission pad for wireless power transmission comprising: a. a coil; b. a power transmitter having a sweep frequency generator coupled to the coil to provide a frequency varying signal through the coil, thereby generating a variable magnetic field; and c. a controller coupled to the coil and to the sweep frequency generator, wherein when a portable electronic device to be charged is positioned within the variable magnetic field generated by the power transmission pad, the controller is configured to determine a resonant frequency corresponding to a maximum energy transfer from the power transmission pad to the portable electronic device, and the resonant frequency is locked for power transmission from the power transmission pad to the portable electronic device, wherein the resonant frequency is determined by sweeping transmission frequencies of the frequency varying signal across a sweep frequency spectrum, monitoring a characteristic of the pad or of the portable electronic device in response to the variable magnetic field, and selecting a specific frequency according to the monitored characteristic.