WIRELESS POWER TRANSFER

A power receiver (105) wirelessly receives power from a power transmitter (101) via an electromagnetic power transfer signal and comprises an input circuit (107, 501) with a receiver coil (107) extracting power from the power transfer signal to generate an induced power signal. A rectifier circuit (503) rectifies the induced power signal and comprises a switch element, such as a FET, arranged to switch a path between a conductive mode and a non-conductive mode in response to a switch control signal. A rectifier controller (507) generates the switch control signal in dependence on the induced power signal. A load modulator (511) receives data for communication to the power transfer and generates a load modulation signal indicative of load variations representing the data. The rectifier controller (507) is arranged to adapt the switch control signal in response to the load modulation signal. The approach of load modulating the power transfer signal using the rectifier circuit may provide improved performance.