Texas Instruments flyback circuit solution

muhejian

Texas Instruments flyback circuit solution [Copy link]

This is a reference circuit of 400V to 12V based on UCC28610 from Texas Instruments. I don't understand the circuit on the upper right (T2 transformer). Can anyone tell me what this circuit is for? Thank you very much.

muhejian

Attached is the complete circuit diagram

maychang

"I don't understand the part above the upper right part of the circuit (T2 transformer). Can an expert tell me what the function of this part of the circuit is?" This part of the circuit is used to control Q4 for synchronous rectification.

warchiefl

The driving circuit of the synchronous rectifier MOS tube, the transformer induced voltage is used to supply the two NPN amplified signals, the current flows from the second-level NPN to the PNP, and the generated voltage drop drives the MOS tube. At the same time, this driving circuit can also buffer the charge of the parasitic capacitance of the MOS tube.