Pulse stretch circuit

[heena123]

hi,

I want to stretch my in put pulse which have below specification

time period of pulse = 100us
pulse width = 1us
extended up to =100us.

I think for this RC circuit is OK .but i wants to less time to capacitor charge and more time for capacitor discharge.

Please give me guidance for this.

Regards,

Heena

 

[BradtheRad]

Something like this might meet your specs.

The RC time constant needs to be around .2 uSec when charging from a 1uS pulse. The component values shown are a starting point to experiment with.

 

[HTA]

I think it is useful to look at an active monoflop to decouple the input pulse. Here are several solutions: The One-shot Monostable Multivibrator

Enjoy your design work!

 

[heena123]

hi,

thank you for your reply ,

I made this kind of both RC circuit as well as Mono-stable multivaibrator circuit also and simulate in Multisim 11.0 and also your given circuit too.

My signal voltage at input stage is 1 V initially and when Pulse is coming of 1us voltage should go to 2 V but after giving this i/p signal to above circuit's pulse is extended but voltage of this pulse goes in Mili volts also in micro volts..

How can i reduce this effect of voltage which i wants in volts not in mV /uV?


Please give me some guidance for this.

 

[HTA]

Load a capacitor requires energy and if the 1us pulse cant' provide it you need an amplifier OP or camparator to provide what ever is needed on the output (your load).

Enjoy your design work!

 

[heena123]

hi,

all thank's for your support .

Now i am using dual mono stable ic for pulse stretching for both rising & falling Edge for different T time

It's working good,its HCF4098BE .Its works for all different pulse.

Its TPLH & TPHL time is 200ns.

Actually my input pulse is only one kind of pike signal which is more time than 200ns (0.2us) my signal have this configuration is more than this.

So please suggest any IC which have more than this Ratting Like 500ns or more. in mono satble Multi vibrator.

Regards,

heena

 

[HTA]

Hi Heena,

It is not clear to me what you want to get from your input pulse. One 100us pulse? The length of the output pulse of the monoflop can be adjusted by the resistor and capacitor, as seen and described in the data sheet. Also 100us.

Enjoy your design work!