Question: About multi-channel output voltage regulation

Aguilera

Question: About multi-channel output voltage regulation [Copy link]

The figure below is a flyback multi-channel output circuit. If both 5V and 3.3V are output normally,

The voltage-dividing resistors R1 and R2 will bias the transistor Q1. If Q3 and Q2 are in the off state, can the 3.3V below still be output normally?

How do Q1, Q3, and Q2 work? Let the experts in the forum help analyze it.

maychang

"Q3 and Q2 are in the off state, so can the 3.3V below still be output normally?"

Your diagram is incomplete. I guess the 5V and 3.3V circuits have separate rectifiers and filter capacitors, and both circuits can work, but only one circuit can be stabilized (not shown in the diagram). The circuit you posted may be to redistribute the current between 5V and 3.3V.

maychang

It is best to post the rectifier filter circuit and feedback circuit of the multi-channel output of the flyback circuit in full.