DIY High Power LED Rechargeable Flashlight

[What's_nitro?]

Well the Fairchild FAN2500 looks promising with a 0.1v dropout. Plus they have a built-in switch on Vout. It's only rated for 100mA/300mA continuous/peak output so you would need about 35 of them... but who's counting? I suppose fewer of them could be used at the expense of higher dropout voltage.

[sikeston34m]

I laid the LED on an 3" aluminum disk and ran it for about a minute straight. This kept the LED much cooler and only warmed the disk up lukewarm.

If the LED is only being fed it's rated voltage AND heat is controlled, why is a driver needed at all?

I realize there are dimmer driver boards that allow modes of operation.

25%, 50%, 100%, flasher and even SOS signals.

I just want 100% or nothing. Simple Enough.

[BrianG]

Originally Posted by sikeston34m

I laid the LED on an 3" aluminum disk and ran it for about a minute straight. This kept the LED much cooler and only warmed the disk up lukewarm.

If the LED is only being fed it's rated voltage AND heat is controlled, why is a driver needed at all?

I realize there are dimmer driver boards that allow modes of operation.

25%, 50%, 100%, flasher and even SOS signals.

I just want 100% or nothing. Simple Enough.

The current through the LED is (Vsupply-Vled)/resistance. So, if the supply voltage exceeds the LED rating with no resistor, current is theoretically infinite. You can guess what happens then. Your only saving grace is the fact that 1s isn't enough voltage to fully turn the LED on. It works, but sure it leaving things to chance. Controlling the LED current will greatly extend its life.