Variable Pulse Width Generator

Hello,

I am in need of a variable pulse width generator to control the intensity of some LEDs. I need a low parts count, preferably an 8 pin ic that is easy to implement. I will adjust it with a pot and the PWM generator will drive a mosfet. Anyone have any ideas? Is there a hi-tech replacement for the 555 timer that does o to 100 percent duty cycle?

Thanks,

Royce WN5L

wn5l said:

Hello,

I am in need of a variable pulse width generator to control the intensity of some LEDs. I need a low parts count, preferably an 8 pin ic that is easy to implement. I will adjust it with a pot and the PWM generator will drive a mosfet. Anyone have any ideas? Is there a hi-tech replacement for the 555 timer that does o to 100 percent duty cycle?

Thanks,

Royce WN5L

Click to expand...

Go to the Projects page on my website. Than find the PWM Circuit.
it will do about 1 to 99%, that should be close enough.

A microcontroller is on the top of the list for high tech, nanopower, low pin count replacements for things like the 555. The downside is that you have to come over to the dark side and learn to program. In assembly language no less. It has been my experience that it is easier to teach an engineer or an HRO to program then it is to teach a programmer to design circuits. No offense intended -- it's just an observation.

Royce,

That's a simple microcontroller task. If you're not interested in programming a microcontroller (understandable) and the simple circuit below is similar to what you're lookin' for, I'd be happy to post you a programmed "one off" device this weekend.

BTW, I use something similar to the 2nd circuit below (copyright Micro Application Consultants) for recessed accent shelf lighting in "the shack".

Take care. Very 73, Mike - K8LH