How do I use one feedback pin with two error amplifiers?

Question

I know there is a similar question asked: TL494CN and error amplifier.

However, that link does not answer my question. If I need one current loop and one voltage loop on the power supply, how should I connect the pins? Won't the two loops interfere each other?

For the loops I mentioned above, I mean something like "if current is too high, move into constant current mode". I suppose I need two loops for this application, one sensing current and one sensing voltage, while the lower duty cycle given is selected by chip.

Answer 1

The two loops won't interfere if designed properly - the loops need to be nested so that one takes overall control and can override a demand set by the other.

For your example, the output voltage is set by a demand - this demand is just a voltage level set by (say) a potentiometer under control from the user. If the output current rises beyond a certain point, the electronic circuits can artificially modify the pot value (in effect lowering the demand) to reduce the voltage to keep the current from going beyond a specific point.

That's how it would be done in a power supply.