what drivers are available for 1aa

[aljsk8]

what is the best driver / regulator etc for a 1aa (1.2v nimh) cell flashlight im looking for 350 - 750ma (by that i mean 1 level but anything in-between those value's)

i want best efficiency and durability (if i can have both)

let me know whats available (needs to be 20mm or less in diameter)

thanks

alex

 

[TorchBoy]

Constant current drivers seem to be pretty rare.

 

[chimo]

If you are concerned about run-time, you may be better going for the low end of your desired output.

You didn't mention what you are driving, so let's assume a high poer LED that has a Vf of 3V at 350mA.

Power to the LED is 3 x 0.35 = 1.05W

High efficiency drivers at this voltage are hard to find, but let's pick 80% as a rough efficiency.

Power to the driver has to be 1.05/0.8 = 1.31W

Current from a 1.2V cell is 1.31W/1.2V = 1.1Amps

That's a fairly high draw from a AA cell. If you only plan on using NiMH, one of Lambda's MiniPro drivers will put you in the range and give a fairly constant output (due to the NiMH's relatively flat discharge curve).

 

[Essexman]

This thread may be helpful LINK, DX also sells the same driver.