Help with Analog control for a Boost converter

HI every one I wonder if any one can help me a little bit....well here is my problem.

I´m trying to design an analog control for a 12v-36v boost converter, I already have the inductor and capacitor values of the boost, but I wonder if any one have made before the analog control for a similar converter, using LM318N, LM339N and HCPL 3120.

Thanks