variable 0-24v referance voltage from a 555 voltage doubler

[user1453]

Hi
Would it be possible to generate a variable referance voltage (0-24v) for comparitors from a 12v suply rail by

using a 555 based voltage doubler to boost the voltage to 24v
**broken link removed**

and then feeding the outut voltage into one of these


I assumed that since the 0-24v is being used as only a referance voltage by the comparators the current requirerment would be negligable.

Is this setup feasible?

 

[kchriste]

You won't get 24V out of this circuit. You have to subtract the voltage drops of D1 & D2 and the fact that the 555 output will not go rail to rail.

and then feeding the outut voltage into one of these

You won't need the bridge and transformer though. Your current will be limited by the 555's capabilities. I would guess you won't get more than 50-100ma output until the output starts to drop off. You'll also have additional voltage drop though the LM317.....

 

[user1453]

the voltage only needs to 0-12v, I was thinking of using the 555 doubler to braise the voltage babove 12v to accounte for the voltage loss