Patent ID: 7522878

Claim:
A contactless power supply for inductively providing power to a remote device comprising: a resonant circuit having at least one of a variable capacitor with a variable capacitance and a variable inductor with a variable inductance, said resonant circuit having a variable resonant frequency that varies as a function of said at least one of said variable capacitor and said variable inductor, said resonant circuit having a primary for transferring power to the remote device; a receiver for receiving information from the remote device; a switching circuit electrically coupled to said resonant circuit, said switching circuit operating at a variable operating frequency; a circuit sensor operatively coupled to said resonant circuit, said circuit sensor generating a sensor output; and a controller electrically coupled to said circuit sensor and said receiver wherein said controller is programmed to: (1) vary the variable resonant frequency of the resonant circuit in response to information received from the remote device by at least one of (i) varying said capacitance of said variable capacitor of said resonant circuit; and (ii) varying said variable inductance of said variable inductor of said resonant circuit; and (2) vary the variable operating frequency of said switching circuit in response to said sensor output.