Abstract: A wireless power transmitter can include a wireless power transfer coil designed to magnetically couple with a corresponding coil in a wireless power receiver to facilitate wireless power transfer from the wireless power transmitter to the wireless power receiver, a power converter configured to drive the wireless power transfer coil, and control and communications circuitry coupled to the wireless power transfer coil and the power converter. The control and communications circuitry can be configured to operate the power converter to drive the wireless power transfer coil so as to transfer power to the wireless power receiver in accordance with a negotiated power transfer. Simultaneously during power transfer, the control and communications circuitry can send a polling signal to detect a foreign object including a wireless transponder and reduce or stop wireless power transfer upon receiving a response to the polling signal from a foreign object including a wireless transponder.