1aa boost?

aljsk8

Enlightened
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Sep 7, 2006
Messages
435
Location
Wigan, UK
ok simple question

does there exist a fenix size circuit that will boost 1aa 1.2v - 1.5v battery
to more than 350ma - say 500ma or 750ma - or is this just a dream?

this is for use with a 1aa fenix style torch using a seoul P4 led

i do not want to run li-ion (so not flupic im guessing)

hope someone can point a beginer to drivers in the right direction

Alex
 

mzzj

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Feb 8, 2007
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Finland, Oulu, beyond 65N
It should be possible with good quality nimh-batteries, but I am not aware of any such drivers.
I was looking for switcher ic's some time ago for similar purpose and coud'nt find any with enough power @ 1v input voltage.

Designing my own is one option, tiny step-up ic to power ucontroller/smps-controller and mosfets so that I can use easily availlable controllers and mosfets that require 3.3v to operate. Fitting actually 2 step-up converters to tiny lamp is another thing...

Anyone got neat ideas how to start 3.3v circuitry/switching ic's with 1.2v battery? Using tiny 3v watch lithium battery is one option.. :D
 

gadget_lover

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Oct 7, 2003
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7,147
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Near Silicon Valley (too near)
I picked up a 1 watt MXDL powered by an 1AA. IT was pulling .75 amp from the lithium (L91) battery. I replaced the LED with with a luxeon III tv1j that was sitting in my spare parts box.

The light now sucks 1.25 amps, (1.25 * 1.5 = about 2 watts) and is brighter than a RWOH 1 watt luxeon running 400 ma. I did not measure the amps at the LED.

It can be done.

Daniel
 

leeleefocus

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May 25, 2006
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193
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UK
Send Millermods a PM. He used to sell a driver for the fenix lights which is almost as you describe but because of the high current draw from the batteries the use of alkaline batteries will give you poor performance but use NI-MH and it works a treat.
 

Martin

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Apr 5, 2006
Messages
584
Location
Germany
The LT guys are experts on this sort of thing.
Look at the datasheet of their LTC3490 and take note how efficiency comes down at 1 V. This is for 350 mA load.
For 500 or 750mA output, efficiency becomes more of an issue so that a healthy design in this power range uses 2 cells.
You might still find converters that do what you ask for, but check them at the lower end of the battery's discharge curve. Chances are that not only efficiency drops massively, but they even can't maintain the initial current.
 

UncleFester

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Apr 28, 2004
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Desert Hlls,AZ
LOL Martin you beat me to it. I think with a little carressing, the 3490 just might be the ticket. It's quite possible that some CPF modders are already using it, but aren't really intrested in giving away they're intellectual property. and and rightly so.
 
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