System for turning off a synchronous rectifier based on a primary switch turn-on detection

A method for turning off a synchronous rectifier (SR) based on a power switch (PS) transistor turn-on detection in a flyback converter, the method comprising:

• detecting, with a spike detector having a terminal coupled to output capacitor in series with a secondary winding, an increase of an output voltage across the output capacitor in series with a secondary winding;
• and
• turning-off the SR transistor in response to the spike detector detecting the increase of the output voltage.

A system for turning off a synchronous rectifier (SR) transistor based on a power switch (PS) transistor turn-on detection in a flyback converter, the system comprising:

• a spike detector including a terminal coupled to an output capacitor in series with a secondary winding of the flyback converter, wherein the spike detector is configured to detect an increase of an output voltage (VOut) across the output capacitor when a second primary switch transistor for the flyback converter is turned-on;
• and
• an SR controller in signal communication with the SR transistor and with the spike detector, wherein the SR controller is configured to turn-off the SR transistor based on the spike detector detecting the increase of the output voltage.