Need help on a driver board

Let me first start off by saying I've used the search function on here, and after about 2 hours of looking I think I'm even more confused then when I started. LOL! Anyway, what I am looking to do is drive 3 leds in parallel off of 3.7-4.5V max, regulated anywhere from 700-1100mA each. Any ideas on what I can use? I've seen the tri-flupic, but they don't seem to be available anymore, and I'm not even sure if it would work in this situation. Thanks for any help in advance, this place is the greatest! :twothumbs

anyone? thanks!

I'm not aware of any driver that will do that. That may explain the lack of any responses.

Do you want to use a single driver to run all three LEDs or could I interest you in something else? https://www.candlepowerforums.com/posts/2340546

Three of these might do the job, or a two or three AMC7135 board to run each LED would work, depending on whether you wanted 2/3 amp or 1 amp.

TorchBoy said:

Do you want to use a single driver to run all three LEDs or could I interest you in something else? https://www.candlepowerforums.com/posts/2340546

Three of these might do the job, or a two or three AMC7135 board to run each LED would work, depending on whether you wanted 2/3 amp or 1 amp.

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Because of space constraints, I was looking for a single board to run all three. I saw your driver board post, thanks for doing that! Unfortunately, I dont see anything that can output the kind of amperage I need out of ~3.7V.

ambientmind said:

Because of space constraints, I was looking for a single board to run all three.

Click to expand...

That must be some serious size constraint. If space is that tight I suppose you can't carve some space out of the heatsink either.

So... :devil: Use a resistor or three (preferably three, or one for each LED). If I understand correctly, you're not after perfect current regulation, so use a 1-1.2 ohm (depending on Vf), 1 watt resistor for each LED. Starts on 1,000mA, finishes on 200-300mA (again, depending on Vf, and it's a bit lower than the 700mA you wanted). Total volume about the same as a thick regulator board. :thumbsup:

Putting them in parallel could also cause problems. The Vf of each LED could be different, which means when you put them in parallel they will not get the same current per LED.

FWIW with my own Crees I've measured a Vf @ 1A of 3.3-3.6V.

TNC had a Tri-Flupic available earlier today here . . . .