inverter using ic 3524
I think I understand what you intend to do: Making a simple sine wave inverter, using a 50Hz power transformer, dirven in push pull or with a bridge, and pulse-width-modulating the driving transistors to create the sine wave. That was commonly done in "ancient" times, but nowadays it's not done much, because such an inverter is heavy, and the loss at zero or low load is rather high.
Anyway, to modulate a sine wave function with a 3524, you can put the sine wave into the COMP pin, which will override the error amplifers. If you put in a sine wave that swings between roughly 1 and 4V (the exact levels need to be adjustable), then the output pulse width will be modulated from zero for the negative peak of the sine, to half length for the zero crossing of the sine, to full pulse length for the positive peak of the sine.
The problem is that this is NOT what you need to drive such an inverter's power circuit! For a push pull, you need instead a drive circuit that modulates one output from zero to full pulse length and back, modulating one HALF wave of the sine wave, while keeping the other transistor off, and then does the same again, but on the second transistor, keeping the first one off! The 3524 cannot do that. Maybe there is an IC that can do this, but I don't know it. I have seen such inverters implemented with more discrete circuitry, or with a microcontroller.