Apple Inc.
Wireless power transfer system and devices

Abstract:

A wireless power transmission system comprising a wireless power transmitting device and a wireless power receiving device. The wireless power receiving device is configured to regulate power drawn during a power transfer phase to maintain a substantially steady power level that is less than or equal to a power consumption level demanded by an associated load. The wireless power transmitting device is configured to determine the presence of a foreign object by monitoring the power transmitted or the power received and identifying a characteristic change in steady state power indicative of the presence of a foreign object.