unity gain buffer for feedback

[--BawA--]

i have made a DC DC converter using pic microcontroller , input is 12vdc and output is 311vdc .
For feedback , i have used voltage divider network ,so my question is " should i use a unity gain buffer after voltage divider to protect the microcontroller ADC pin from high voltage .?

 

[asadi.siyavash]

yes it is very important to use buffer also I suggest to use diode protection for this pin with Diode like BAT54S.

 

[--BawA--]

can you suggest me any optocoupler , best suited for this application?

 

[asadi.siyavash]

first you should say for which part of your circuit do you need optocoupler ? if you send any circuit I will can help you better.