From: Lizard Blizzard
Subject: Re: Best way to power array of LEDs?
Date: Thu, 07 Nov 2002 08:44:39 -0800
References: <0001HW.B9C26E7400A7161B165FEAC0@news.covad.net> <2Qan9.3129$cS4.firstname.lastname@example.org> <3DC843FE.4A25FFF3@fanwap.com> <3DC99AD4.2AB0FE52@fanwap.com> <3DC9A173.812F4764@fanwap.com> <3DC9B37F.453F9C41@fanwap.com>
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Nucharin W. Jansen wrote:
> He parallels all LEDs together without any resistor to
> constant voltage regulator.
If you read the rest of it, he says that the LEDs are all run at
substantially below their maximum current to get better efficiency.
Something like 8 mA, in one of his designs. So if you have one LED that
has substantially lower Vf, and it decides to hog twice the current,
then it's still only 16 mA, which is well below the maximum, so no big
deal. But putting LEDs in parallel without Vf matching and running them
at or near maximum is just an invitation for self-destruction.
> At last week, I thought the same as him but I plan to do with
> MAX757 ( DIP300 ) stepup IC from batt only 1 or 2 cells.
> But after read several articles here, I get confuse so much.
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