TRANSMIT POWER CONTROL FOR A WIRELESS CHARGING SYSTEM

摘要

Exemplary embodiments are directed to wireless power transfer including generating an electromagnetic field at a resonant frequency of a transmit antenna to create a coupling-mode region within a near field of the transmit antenna. A receive antenna placed within the coupling-mode region resonates at or near the resonant frequency. The receive antenna extracts energy from a coupling between the two antennas. A load sensing circuit coupled to an amplifier driving the transmit antenna can detect a change in power consumed by the amplifier in response to the energy extracted by the receive antenna. The transmit antenna adjusts to a high-power charging mode when one or more receivers are present in the coupling-mode region and adjusts to a low-power beacon mode when there are no receivers in the coupling-mode region.