Apple Inc.
Wireless power system with efficiency prediction

Abstract:

A wireless power system has a wireless power transmitting device and a wireless power receiving device. During digital ping operations while the transmitting device and receiving device negotiate to establish a power level to use during normal operation, low-power wireless power signals may be transmitted to the receiving device from the wireless power transmitting device. Information gathered during the digital ping may be evaluated using a wireless-power-transmission-efficiency-to-digital-ping-rectifier-output-v- oltage relationship and using a normal-operation-wireless-power-transmission-efficiency-to-digital-ping-w- ireless-power-transmission-efficiency relationship to predict a wireless power transmission efficiency that would be experienced if the system were to enter normal operation. Based on this efficiency prediction, the system can issue alerts and can decide whether or not to enter normal operation.