Suggest a PWM controller

Hi 

I want  to control the current in the load  ; 

We use IGBT where the igbt frequency is low ; 8khz would be ok ; as you see in the sketch shematic we set the required current from DSP dac and compare it with current  in the load via refrence resistor; then the comparator turn oFF or ON ; but we need a PWM controller that limit the switching  frequency to 8khz  with maximum  duty cyle 100% 

You may suggest other solutions too 

Thank you in advanced 

3806.CURRENT.PDF