Hello,I am a beginner to electronics and after researching in internet I came to know that we should use comparator and counter to do the same and I tried to do the same using logic gates and flip flops.But I guess it is not working properly.So I request anyone to help me by identifying the mistake in circuit and how to rectify it.I have attached it below.Thank you

 

I can not see details.
It looks like there is a ADC that reads the pot and output a 8 bit number. Is that working?
Looks like there is a 8 bit counter. Is that working?

I think you are getting a pulse of 1/256 every time there is a compare. Are you getting a very short pulse on the output?

I would put a SetReset FF at the output. The compart signal resets the FF. Look at the counter and make a circuit that has a output when the counter reaches FF or 00 and that drives the sets the FF.

 

Thank you very much for replying to my message @ronsimpson .I guess both ADC and 8 bit counter is working .When I simulate,it is on for some long time and off for some time and same again.I guess it is not like pulse.I can send you the proteus file if u have proteus installed in your system so that you can simulate and correct me.Thanks

 

It would be far simpler to generate the PWM directly from the analog input.

Assume the input is 0-10V.

Generate a ramp from 0 to 10 V and the PWM out is just an analog comparator of the input to the ramp., i.e. the output is high whenever the input is greater than the ramp.

 

Why do you want to convert the analog to digital, and then back to PWM analog?

 

As a beginner, I can come up with a circuit using an analog comparator.
When implemented in a microcontroller, Vramp is generated by a counter and the output is controlled by a compare-match timer.
Voltage- and Current-Mode Control for PWM Signal Generation in DC-to-DC Switching Regulators
If you intend to construct logic for academic reasons, my opinion is not helpful.