Voltage controlled one shot 1

[RickOzone]

I'm looking for some circuit ideas to implement a voltage controlled one shot timer that would be triggered periodically. The input would be a voltage from 1-5 Vdc and a trigger to start the timer. The output would be a single pulse with a duration linearly dependent on the input voltage. After the pulse the timer would be triggered again. Any ideas?

 

[melone]

555 timer. Look it up at

http://www.national.com

or

http://www.onsemi.com

 

[EDN007]

I call this A Voltage Controlled Pulse Width Modulator
(VCPWM). I just think it sounds good.
This could be implemented with a small micro controller.
The micro controller must have an ADC.
If I understand correctly, then this would allow you to do things such as the following
cycle || Input Level (V)|| Output Width (ms)
1 || 0.5 || 5
2 || 1.5 || 15
3 || 4.5 || 45
4 || 2.7 || 27
and on
Let me know if you need more help

 

[automatic2]

There are numerous power control ICs that perform PWM duty in relation to voltage in. TI, SG, Motorola, etc.,. select a device that has an inverting input to make it a one IC solution.

 

[RickOzone]

Hello,

The 555 timer seems to have done the trick. I used pin 5 as the voltage input to vary the pulse width.

Thanks all