Square wave input, PWM output?

[rsajan1]

Hi folks,

I'm trying to find an IC or simple circuit that gives a pulse width modulated signal for a DC voltage input. For example, the input to this would be a square wave alterating between 0 and 5V. When the input is 0V, the output is 0V but when the input is 5V, the output should be a 0-5V square wave with a controllable frequency.

The input comes from a comparator, maybe there are comparator ICs that have this as an in-built function? I cant seem to find any.

Thanks!

 

[rob_croxford]

Do you want to vary the Frequency or the Duty cycle?? PWM is generally a variance in duty cycle to control the gate pin of a swtiching device, for instance. Or it can be used to vary the direction of a servo motor...

What is your application?

 

[Iron Will]

This might be of you interest.
http://www.cirrus.com/en/pubs/training/apex_tech_sem/PwmBasics.pdf

 

[BobK]

Hi folks,

I'm trying to find an IC or simple circuit that gives a pulse width modulated signal for a DC voltage input. For example, the input to this would be a square wave alterating between 0 and 5V. When the input is 0V, the output is 0V but when the input is 5V, the output should be a 0-5V square wave with a controllable frequency.

The input comes from a comparator, maybe there are comparator ICs that have this as an in-built function? I cant seem to find any.

Thanks!

This is contradictory. An input cannot be a DC voltage AND a square wave.

Bob