Method for driving a resonant converter, and corresponding device and computer program product

A resonant converter, comprising:

• a primary switching circuit including,
• a primary winding;
• a resonance inductor coupled in series with the primary winding;
• and
• a primary full-bridge switching circuit including an upper switching half-bridge circuit and a lower switching half-bridge circuit coupled to the resonance inductor coupled in series with the primary winding, the primary full-bridge switching circuit in operation driving the primary winding coupled in series with the resonance inductor in response to switching control signals;
• a secondary resonant circuit having a secondary winding magnetically coupled to the primary winding and a resonance capacitor electrically coupled to the secondary winding;
• a secondary rectification stage coupled to the secondary winding of the secondary resonant circuit that in operation rectifies a signal across the secondary winding in response to switching control signals;
• and
• a driving circuit that in operation detects whether a phase signal, which is provided by one of the upper and lower switching half-bridge circuits in response to a first control signal applied to the one of the upper and lower switching half-bridge circuits, exceeds a first threshold value, and the driving circuit in operation, in response to the phase signal exceeding the first threshold value, controlling a time shift between the first control signal and a second control signal applied to the other one of the upper and lower switching half-bridge circuits, and the driving circuit in operation adjusting the time shift each switching cycle of the first and second control signals until the phase signal does not exceed a second threshold value.

A method, comprising:

• receiving phase signals on phase nodes of an upper switching half-bridge circuit and a lower switching half-bridge circuit of a resonant converter, each of the upper switching half-bridge circuit and lower half-bridge circuit including a high-side switch and a low side switch;
• driving a primary winding and a resonance inductive element with the phase signals;
• detecting an under voltage or an over voltage in the phase signals;
• providing a time shift between a first control signal applied to the high-side and low-side switches of one of the upper and lower switching half-bridge circuits and a second control signal applied to the high-side and low-side switches of the other one of the upper and lower switching half-bridge circuits;
• and
• reducing a value of the time shift starting from an initial nominal value by an incremental value each cycle of the first and second control signals until the under voltage or over voltage in the phase signal is approximately zero.