Help on circuits to run a 1w luxeon

I decided it was time to start learning about the electronics side of this hobby so I bought a Q4H low dome 1w star from the shoppe to experiment. I figured that was cheap enough so that if i fried it it wasnt too big a loss but good enough to still make a decent flashlight. So from what ive read the most you want to run these at is 350ma.
I dont want to direct drive it because A, that would be too simple, and B, I dont want it to get dimmer and dimmer as it completes the battery. So I guess Im looking for regulated circuits to run these things. I have had thoughts of rnning one of these things in a 1-123 light so no voltage step would be required, but would also like to know how to run one on 2-123's, stepping the 6v down to 3 and getting longer run times.
Problem is, with all the looking back through all the posts in these forums, and on personal websites, I havnt seen much on circuitry. Can anyone point me in the right direction.
I have a fairly good understanding of electronics, Ive built pulse width modulation power supplies for DC motors, and firing circuits for the electronic ignition of fireworks, I just had to do allot of research and studying first, which is what Im trying to do hear. Any help would be much appreciated.
Thanks

Tim M. /ubbthreads/images/graemlins/smile.gif

For 6V -> Luxeon 1W or 3W you need a down converter. A popular switcher is the Linear Technology LT1618. It is quite a flexible device with current sense pins. Various topologies can be implemented with it to create an up converter or a down converter. It runs at relatively high frequency which is nice for using small inductors and capacitors. The LT1618 is starting to show its age now that folk are trying to drive higher & higher currents into Lux III's etc - but around the 350mA - 500mA for up converters it does pretty good and for down converting you can go to maybe 1000mA or so before the efficiency starts to degrade due to the internal switch.

You can see more at LT1618 datasheet

george.

Heres another idea.
I have the Q4H LD star as stated.
Yall tell me what to do with it.
Should I get a micropuck from elektrolumens?
Only thing about that is it says that it drops off like an ican
does. Am I going to find anything better?
Tell me what to do.
Thanks

Tim M.

try the sandwiche shoppe
http://www.anlighten.com/shop/default.php
look under the convertor boards section, there are convertor boards for most of ur needs
badboy , can choose from 3,4,5,700mA stepup
downboay, can choose from 400mA, (dont have 700 in stock at the moment) step down boards
wizard board is both a step up and step down board
for your 1watt lux, choosing badboy means running on 1 123 cell
for downboy, you can run from 6volts upwards
for wizard board, i think you can run on any voltage but i can be wrong , please check specifially at the shoppe
btw, you can overdrive the 1watt to 700 /ubbthreads/images/graemlins/smile.gif
hope this helps
cheers mate
Des