A front-end circuit is disclosed for a resonant wireless power receiver, the circuit comprising: input terminals for connection to an antenna; a rectifier configured to rectify an AC signal having a peak input voltage received at the input terminals and to provide an output having an output voltage; an over-voltage detector configured to at least one of detect the output voltage exceeding a threshold voltage an overvoltage and detect the peak input voltage exceeding the threshold voltage; and an over-voltage controller configured to provide an electrical short-circuit across the input terminals in response to the respective output voltage or peak input voltage exceeding the threshold voltage. Integrated circuits, NFC devices and mobile device comprising such a front-end circuit are also disclosed, as is a method for controlling wireless charging.