Very low duty cycle pulse generator design

[Deesha]

I have a problem. I need to design a pulse generator circuit with on time of 100nanoseconds n duty cycle of 1%. The amplitude of this pulse must be 3.3V. Can i get any help on that please?

 

[btbass]

use google to search for "transistor multivibrator circuit".
It might do what you require.

 

[FvM]

100 ns and 10 us time intervals can be easily generated with monoflop logic ICs. Two of them can be combined to a pulse generator.

 

[enjunear]

**broken link removed** might be worth looking into. The abstract says the circuit, as shown, can do 20 Hz-13 kHz, but can be adjusted by tweaking C1. I'd probably mock it up in SPICE to see how the performance is at a 100 kHz rep rate.

From initial inspection, it looks like most PWM circuits out there... a triangle-wave generator and a comparator.

 

[Deesha]

Thank you very very much for all your help! im still not sure about the design n am working towards it. if there are any troubles i will get back for further assistance.

 

[zuisti]

...I need to design a pulse generator circuit with on time of 100 nanoseconds n duty cycle of 1%. ...

This means that you want to get an 1 (one) nanosec width output pulse ?

My humble opinion, it's almost impossible to realize it as a DIY circuit. Sorry ....
Of course it's possible to generate a 100 nanoSec pulse with 10 microSec periodic time .. : - )

 

[halee awan]

you can use 555 timer for this purpose
100kHz not too much
8O

 

[Deesha]

but the 1% duty cycle is the hitch. 555 timer i think their rise time itself poses a problem.

 

[zuisti]

Yes, the 555 is too slow to do this.
As FvM wrote above, use two monoflops.
The HC123 is a dual monoflop, working at 2...6 v, min. output pulse width < 100 nS ...
**broken link removed**

 

[Deesha]

i am hoping the circuit enjunear has posted will work.
Trying to get the max4232 ic now. Most dealers don't have stock.
I dont have the pspice s/w. If i could get help simulating it then, it would help me purchase the right values of resistors and capacitors.

 

[halee awan]

ok ..But 555 timer has Rise and Fall time 100nSec

 

[kalaianand]

555 timer is a good choice. it has good rise and fall time. Whats the application you are going to use?