Hi , I wish to do the following .

I'm working with cmos btw , under 100 khz .

I'm looking for some circuit or chip that can do this .

Thx you

 

Hi , I wish to do the following .

I'm working with cmos btw , under 100 khz .

I'm looking for some circuit or chip that can do this .

Thx you

You are going to have to help us out by describing what "this" is.

Nevermind, I see you have added an attachment.

hgmjr

 

What is the frequency of the input signal and what is the pulse width of the pulse you need to form off of the positive going edge?

hgmjr

 

It looks like what you may be needing is a one-shot. One IC that comes to mind immediately is an MM74HC123.

hgmjr

 

well I would like to control the pulse width also , it should be very tiny but I fear this will be too tiny .

The tiny little pulse should be terminated when my comparator reaches 0 volts , IE , another pulse .

 

What are you using the comparator to do?

hgmjr

 

hgmjr is right. 123 is the right part to use here.

take a look at its datasheet and you will know how to control pulse width.

 

At this stage, we need to establish what voltage you were planning to use to power your design.

hgmjr

 

Can you have a delay and how much between the rising edge of the clock and the pulse you want to create?

John

 

10 to 15 volts maximum

regular cmos ranges

basicy , that short pulse should end when my capacitor voltage is below 5 millivolts ( fast comparator pulse )

this is too make sure my capacitor is empty

the pulse controls a transistor wich "tries" to totally discharge a capacitor as fast as possible . ( pF range , dont worry )

 

10 to 15 volts maximum

regular cmos ranges

basicy , that short pulse should end when my capacitor voltage is below 5 millivolts ( fast comparator pulse )

this is too make sure my capacitor is empty

the pulse controls a transistor wich "tries" to totally discharge a capacitor as fast as possible . ( pF range , dont worry )

You will not able to use the 74HC123. It is intended for 5V use. You will need to use the CD14538.

hgmjr

 

well , that chip is much too rare , had trouble even finding the datasheet .

There has to be an easier way .

This is what I would like to achieve .

 

Digikey has them for 80 cents each.

hgmjr

 

thx you hg

but I need something more common , this IC is too <snip> .

 

Cap coupled input to RS FF???

 

Thread closed at request of OP.