Dear support member,
My customer used UC2845A.
Bias winding feedback system using UC2845A FB terminal is adopted.
2.5V is input to the FB pin from the bias winding on the input side via a voltage dividing resistor.
FB terminal is the inverting input terminal of the error amplifier so that it is always 2.5V.
By controlling the bias winding voltage using FB,
As a result, the secondary output is stabilized.
I have a question.
At this time, if the voltage of the FB terminal becomes 2.5V or more, the control IC is turned OFF because the output terminal (= COMP terminal) of the error amplifier falls to GND.
Is there a problem with this behavior?
If the phenomenon of Q1 occurs, can it be used as an overvoltage protection circuit that turns off the control IC when the bias winding voltage becomes overvoltage for some reason and the FB pin voltage becomes 2.5V or higher?