This is a circuit that will be a part of a TL494 PSU that has a bipolar output. In the full circuit the TL494 feedbacks the positive rail that is coupled with the negative using a coupled inductor however when the negative gets loaded it starts to duck and generates a sawtooth at audible frequency. This addon will trace the negative rail and inject its output(the 1st op amp's output) to the non-inverting pin of the 1st error amp in the tl494.
