Zebralight has been using such drivers for a long time now, but are there any available that can boost voltage to fully power an LED?
I too wish I knew of a buck-boost current regulated circuit we could buy off the shelf (flashlight gods, are you listening?)
Too broad of a statement. What type of cell? What type of LED? What type of currents? Single, dual, or multimode?
this is the only one I’ve seen that can work off 3.7V:
http://www.intl-outdoor.com/boostbuck-318v-triple-xml-circuit-board-p-542.html
although it probably won’t work with a single cell and single LED. dhtrckt (?) is getting one for a spotlight he’s modding. There are some others on DX and KD, but the only ones I saw had a minimum 6V input (so 2S).
nickelflipper: Single 3.7v liion of course. Thought that was clear because a lot of people want one..
XML, Nichia.. 1A would be fine, 5A also. Nichia has a vF of about 3.7v at 1.5A though..
I find the LTC3454 Buck/Boost driver IC intriguing, although it is just 1A. Been meaning to draw up a board for it and test it out. Not sure if you could parallel the outputs to make for more amps or not?
I don’t quite get you. You mean a normal boost driver? Like in SK68? That’s been around like forever. It sucks juice from unprotected 3.7V batteries until truly dead. Not sure this is what you would want.
What everybody wants is a driver that will buck the voltage down if the battery voltage is above the LED Vf and boost it up if it is less than the Vf. That way the light output remains constant regardless of the cell voltage.
So many people love their Zebralights and we still have to explain how their driver works? ;)
Constant output to the LED. Whether the cell is at 3.2 or 4.2V.
“zebralights” is replaceable with: car, computer, smartphone, watch, brain (lol!), etc etc 
Seriously: What about all the boost drivers (for 1.5V) that work up to 4.2 V, like the BLF MINI driver for example?
Did anyone ever test those, wheter they also “buck” when used with a single LiIon???
I would guess an operating range of input voltage 1-5V.
Hard to find one indeed, so many drivers around are pure crap.
Most drivers for 1.5V just go into DD when powered with LiIon..
What about regulated drivers, like the 1A 3 mode from shiningbeam? To my eyes that doesnt dim on high until the battery is totally depleted.
tadah! New product on intl-outdoor today!
Looking good. Now something in the 2A, 3A and 5A range? :P
You could ask Hank wheter there will be other versions of this driver available…
…or may be this one can be modded for higher currents….resistor-wise…. :quest: :exmark:
Or burn up…
Has anyone ever used one of these:
http://www.intl-outdoor.com/5a-3mode-2745v-circuit-board-p-547.html
I dont see anything that could boost the voltage..
Well, it never says that it is a boost driver. ;) I know a few sites even list the 7135 based driver as working down to 2.7v.