A switching power supply circuit with synchronous rectification has an energy storage component, a SR switch coupled to a secondary side of the energy storage component, and a secondary control circuit. The secondary control circuit has a turning-ON control circuit for providing a turning-ON control signal based on a comparison of a drain to source sensing voltage of the SR switch and a turn ON threshold, a mode determination circuit for providing a mode signal to determine a turn ON delay based on a detection to a transient event or the drain to source sensing voltage ringing of the SR switch, and a gate driver circuit for driving the SR switch. When the turning-ON control signal is asserted, the gate driver circuit charges a gate voltage of the SR switch after the turn ON delay based on the mode signal, to turn ON the SR switch.