voltage to frequency

[lumley32]

what i need to do is take a fixed frequency with a variable duty cycle PWM and convert it into a variable frequency fixed duty cycle. my idea is to use a RF filter to get the PWM to get it to say a 0-5V output then feed that into something like LM331. the only problem is i don't need such a high output frequency, only need around 1khz output any ideas for a lower output ic?

Thanks in advance!

 

[davenn]

the only problem is i don't need such a high output frequency, only need around 1khz output any ideas for a lower output ic?

what do you mean by that ?

the LM331 works with whatever freq you put into it (up to its max)
if you want a lower freq out, then you put a lower freq in

 

[lumley32]

i have a fixed frequency with a variable duty cycle output, but i need a fixed duty cycle and a varying frequency.

so for example if i put in;

1khz at 75% then i want an output of 750hz and 50%
1khz at 25% then i want an output of 250hz and 50%

nothing needs to be super accurate

sorry if i am not making my self clear but i cant see how to explane it!

 

[BobK]

If the frequencies are really that low, a microcontroller would be the simplest solution.

Bob