Patent ID: 8301079

Claim:
A contactless power supply for supplying power wirelessly to a remote device comprising: a tank circuit having a primary for transferring power to the remote device by an inductive coupling, said tank circuit having a resonant frequency; circuitry for applying power at a rail voltage to said tank circuit, said circuitry applying said power at an operating frequency and a duty cycle; a receiver for receiving information from said remote device; a controller coupled to said circuitry and said receiver, said controller configured to vary in response to said information at least one of said resonant frequency of said tank circuit, said operating frequency of said power, said duty cycle of said power and said rail voltage of said power; throttling circuitry coupled to said tank circuit, said throttling circuitry for throttling said power; a circuit sensor coupled to said tank circuit and to said controller, said circuit sensor providing said controller with an input indicative of a characteristic of power in said tank circuit; and wherein said controller is configured to vary another of said at least one of said resonant frequency of said tank circuit, said operating frequency of said power, said duty cycle of said power and said rail voltage of said power as a function of said input indicative of a characteristic of power in said resonant circuit.