Patent ID: 8513854

Claim:
A driver circuit for driving a resonant load, comprising: an inverter portion that generates an inverter output signal, the inverter portion comprising a controlled switch, wherein the controlled switch comprises a control input for controlling switching operations of the controlled switch; a tuned circuit portion having a resonant frequency when connected to the resonant load, wherein the tuned circuit portion receives the inverter output signal and generates a resonant load driving signal from the inverter output signal, wherein a frequency of the inverter output signal and a frequency of the resonant load driving signal at least substantially equal the resonant frequency of the tuned circuit portion, and wherein the tuned circuit portion boosts the inverter output signal to generate the resonant load driving signal such that an RMS voltage level of the resonant load driving signal is greater than an RMS voltage level of the inverter output signal; a feedback portion that receives the inverter output signal and phase-shifts the inverter output signal to generate an inverter control signal, wherein the feedback portion provides the inverter control signal to the control input of the controlled switch to thereby control switching operations of controlled switch, and wherein the driver circuit self-oscillates at or near the resonant frequency due to the feedback portion phase-shifting the inverter output signal to generate the inverter control signal.