Multiple LSIII driver

Greetings,

I've found that three LSIIIs with a Fraen Tri-Lens make for an excellent mountain bike light. I'd like something more efficient than my current LM317-based current regulator though. Does anyone know of any drivers out there with the ability to deliver this kind of power (roughly 13V at 1A)? Any ICs I should look at if I try a switchmode driver?

Thanks
Duane

If you are running those LSIIIs in series, IMO the only thing more efficient is likely to be direct drive. I've been considering this same application (3 LSIIIs in series @11-16v). I have a 1A LM317 setup but haven't tried it with LSIIIs yet. What I expect is that the 1-2 volts eaten by the LM317 means that I will be essentually running direct off of the battery (11-13v) and current limiting when an alternator (automobile) or other charger (home or RV lights) is applied. I find the drop with the LM317 to be about 1-1.5v (as a voltage regulator - not sure what I'll get in the current regulator) in most of the simpler circuits. This implies an efficiency in the 85% range or better. For battery only applications, where the LEDs would not be on during charging, a small current limiting resistor makes more sense. I just got my LSIIIs and I will try the above experiments & get some current measurements soon, I hope.