US Patent 11063520 Simplified hybrid PWM/PFM control method for SLLC converter

A converter includes input voltage terminals, a series circuit connected to the input voltage terminals and including first and second switches connected in series, a transformer including a primary winding and a secondary winding, a resonant tank connected to the series circuit and including the primary winding, an auxiliary switch connected to the series circuit and the resonant tank, output voltage terminals connected to the secondary winding, and a controller that, based on a single control loop and a single control parameter, controls the auxiliary switch with pulse-width modulation and controls the first and second switches with pulse-frequency modulation.