Circuit and method for extracting amplitude and phase information in a resonant system

Abstract

A resonant power transfer system includes resonant circuitry () including an inductor coil () and a resonant capacitor () coupled to a first terminal () of the inductor coil, wherein the inductor coil and the resonant capacitor resonate to produce an excitation signal (I) and a state variable signal (V). Sub-sampling circuitry () samples first and second points of the state variable signal at a rate which is substantially less than the RF frequency of the state variable signal. Information recovery circuitry () produces a state variable parameter signal representing a parameter (A) of the state variable signal from information in the first and second sampled points. Control circuitry () produces a first control signal in response to the state variable parameter signal. Detection and optimization circuitry () produces a second control signal in response to the state variable parameter signal. Voltage regulation circuitry () produces a regulated supply voltage in response to the first control signal. Switching inverter circuitry produces the excitation signal in response to the regulated supply voltage and the second control signal.