Re: High-output, low-duty cycle LED strobe circuit

On a sunny day (Sun, 3 May 2009 21:21:54 -0700 (PDT)) it happened mj
<elucify@xxxxxxxxx> wrote in
<dda2ac06-f0ff-4535-9de3-68576e4a8651@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>:

I'm looking for ideas on how to make an LED flash so brightly at a low
duty cycle that it's reasonably bright--maybe even close to what it
would be if it were on DC.

I'm building a project where I need to flash white LEDs very brightly
30-50 times a second at about a 0.4% duty cycle. (I'm strobing a
spinning disk, and want to freeze images near the LED--too high a duty
cycle, and the image blurs.) 0.4% is not much time for an LED to be
on. I've heard that you can drive LEDs to up to 10x their normal
forward current without damage (though I guess lifetime is shortened)
if you keep duty cycle to <= 1%.


I have exactly that here, made it for strobe tests.
White LED too, uses an 8 pin PIC, and 2 transistors to get some high current.
Want the asm source? Could perhaps still find it.
.