Demodulation Apparatus and Method for Wireless Power Transfer Systems

An apparatus includes a differential amplifier unit having a first input coupled to a common node of a first coil and a first resonant capacitor, and a second input coupled to a switching node of a bridge, a reference crossing comparator unit having an input coupled to an output of the differential amplifier unit, and a logic unit having a first input coupled to an output of the reference crossing comparator unit and a second input coupled to the switching node of the bridge, wherein the logic unit is configured to generate a signal for retrieving a modulated signal.