Single cell Luxeon driver?

Are there any drivers or easy to follow schematics available for a luxeon on a single cell?

You might do a search for a "two transistor boost convertor" over in the electronic forum.

Dan

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PercaDan said:
You might do a search for a "two transistor boost convertor" over in the electronic forum.

Dan

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I came across a few of those - the problem is they work with 30ma LEDs, not power sucking Luxeons. /ubbthreads/images/graemlins/smile.gif

See what those guys are doing with their Solitaire conversions.

I wonder how useful such a thing would be. Take a 1.2V NiMH AA at 2200mAh, boost to 3.6V @ ~80% efficiency, so you get about 586mAh and you're drawing 350mA, so this thing drains in just under 2 hours. It's simpler and cheaper to use a single 650mAh AA LiIon cell instead...

The original ZLT circuit will work with 1 cell if you adjust the current sense resistor/wire. It will draw a lot of current, but will work. I believe this is what Nukies (sp) is using for his solitaire mod.
Rob

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highlandsun said:
It's simpler and cheaper to use a single 650mAh AA LiIon cell instead...

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But...those cells are hard to find, need a specialized charger, and need protection circuitry for use...especially for something you want to keep in your pocket. /ubbthreads/images/graemlins/smile.gif

re: hard to find, I guess so. Worth the effort though, and also worth the price I think. re: specialized charger - I think it's a worthwhile investment, the Maha 777-plusII is great and it's not like the money's wasted - this thing charges NiCd, NiMH, and LiIon, in all kinds of serial/parallel configs. re: protection circuitry for use - a small value series resistor is sufficient in a Luxeon app; the Luxeon's minimum Vf will cut off the cell before it drains to a damaging level. So it won't over-discharge, and if you use the right charger it won't overcharge either. No big deal.

People used to think NiMH batteries were dangerous when they first came out too, because standard NiCd charging algorithms were bad for them. Now nobody thinks twice about using NiMH vs NiCd...

ArcMania's tiny driver module (used in the Lambda Micro Illuminator) is delivering impressive runtime/efficiencies on a single 1.5/1.2v cell - although I don't think it's driving the Luxeon near rated current (that's OK by me!!). I have no idea what particular circuit components are being used.......

http://home.mchsi.com/~lambda/microil.htm

I've been waiting/hoping someone would come up with an LS driver circuit like this one, that can use readily available and cheap 1.5v batteries in a single cell (pocketable) design. Very cool! Now, if I can figure how to get one into my Infinity's head....... /ubbthreads/images/graemlins/crazy.gif

Bob

LED Mods As Small As Possible uses the ZXSC300 with a hand wound inductor. He has made 1.2 volt Solitaire mods that draw as much as 700mA. Mine is set at 400mA and is quite bright.

I've tested the LED Dynamics Micro Puck with 1.2V driving a Q2K LS. I measured 350mA at 1.2V in and 110mA at 3.1V out. The Solitaire Mod is noticably brighter than the Micro Puck setup I tested.

You need a SMPS.
My friend Christina Mahoney designs SMPSes, but she usually designs SMPSes that run on 150-400v(AC line power) or 12v(automotive power).
She says that SMPSes that run on less than 3v often use a simple feedback circuit to drive the switching transistor, until the controller chip starts up and takes over.