Boost Buck Driver

Flashlight Modding and DIY Parts
1

I am not to informed about drivers and the like but I am trying :bigsmile:

Heres the scenario. I want a boost/buck driver to run alkaline D’s or 3serial a’s which led me to this guy here.
It is obviously intended for XM-L but I plan to use it with 4 XT-E’s.

VF on an XM-L according to the datasheet is 3.35@ 3000ma.
VF on an XT-E according to the datasheet is 3.4@ 1500ma.

Both specs are Max ratings from Cree. I would like to have FULL brightness right around 1500ma/emitter with my quad XT-E’s.

Would this driver put me there? Doesn’t seem to be constant current to me but like I said, I am not a wizarddddd.

2

OOppps Double post….

3

Here’s my favorite place to search for drivers.
http://www.videofoundry.co.nz/ianman/laboratory/research/driverlist.php

4

I used that driver to drive an MT-G2 which is similar to two XM-Ls in series. You would be closer to a 12V output voltage, not sure the driver will like that.
I also had problems running this driver from one cell, it always reported a low battery.
Are you looking to overdrive the emitters, or keep them at 1.5A? Most XM-L drivers will need a minor mod to reduce the output current.

5

I want a maximum of 1.5a per emitter.
VF on the LEDs seem very similar at applicable currents, 3.35@3a vs 3.4@1.5a.
It seems that it wants to see 1, 3, or 4 LEDs. Doesnt state series or parallel but I assume series.

Awwww great. That ruins my plan to use 4D’s…

Is this thing CC?

6

I would expect it to be CC. Your Vf numbers appear backwards, Vf should increase with current.
Using 4D cells may work if the driver can boost from ~5-6V up to ~13V. Possible, it is only double but the driver could have protection limits on it.
If there is no voltage protection, then modding the current limit to get 1.5A should be all you need to do, fingers crossed.

7

i think richie used this driver for 3*xml in series and got over 2A to LEDs (with 2x26650)? ask him, my memory of that conversation is fuzzy.

i’m pretty sure it will be overdriving your emitters with them in series with sufficient battery voltage. on good copper pcbs, you might be ok.

when i tested the driver with 3.8V in and 6V mtg2, it was inefficient, and the driver would likely fail very quickly if not potted.

you might try wiring the emitters in parallel, though I guess you’ll be underdriving them - probably 1A each, or a bit less

8

Man……This looks worse and worse for this driver. I may be wrong, but feel like I would get the voltage warning flashes when the D’s ran a little low and are under load. Seems like a lot of boost to ask from this driver and with all those components on a double sided board, longevity may be a concern without potting like stated…

What is the plausibility of wiring 4 single LED drivers to each emitter from the same +/- sources? That should be okay right?

Fasttech has These that also seem to be an option.

I just got my LED’s in, they are the 4up XT-Es from IS. Beautiful little buggers, the “X” in the die looks awesome too :bigsmile: I have the option of parrallel, series or a combination of the two with this board so I can hinge the driver around that!

The Forward voltages were for the XM-L and XT-E respectively, thats why they seemed wonky.Hehe