×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Voltage controlled one shot

Voltage controlled one shot

Voltage controlled one shot

(OP)
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?

RE: Voltage controlled one shot

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

RE: Voltage controlled one shot

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.

RE: Voltage controlled one shot

(OP)
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

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources