Control system for a resonant inverter with self-oscillating driver

Abstract From the Canadian patent

A controller for a resonant inverter with a self-oscillating driver IC for powering AC loads such as gas discharge lamps or regulated DC/DC converters includes a timing circuit that generates control strobe pulses that are injected into the timing circuit. The timing circuit is coupled to an inverter resonant tank through a feed back circuit providing phase lock for the resonant inverter. The feed back circuit includes a passive phase shifting circuit for 360° closed loop phase shift. Phase controlled strobe pulses automatically adjust IC oscillator frequency for safe and stable inverter operation above resonant frequency. By injecting a small AC or DC control signal into the timing circuit …