LED Driver Circuit

[andrewwynn]

I'm building a few lights.. and for at least one i need a driver... I want to drive a Lux 3 at a varied current between 150mA and 700mA... from a 3.6V batt. The madmax looks like it would do the trick up to 1/2 power.. any suggestions people? anybody out there that would like to help me design such a circuit (space constrants= 7/16 x 1 1/8 rectangle.

The variable power could be controlled by a switched bank of resistors or a pot depending on the method used.

I saw some posts about a uFlex 5W driver.. used pulse-width to be able to run less power than 1/2W and that would be ideal, but the links are all dead.

Thanks in advance for any helpful posts or direct emails:

-awr

aw©rouse•com

 

[Doug Owen]

Yer working too hard. You're very close, but a bit above Vf, ideal place for a Low Drop Out linear regulator (LDO). Look elsewhere in this forum for 'making a nightlight'. Same basic circuit, only use one of the nifty Zetex transistors (the one's I'm using, don't recall the exact number off hand, are good to one amp). Basic parts say $4 (plus switch and resistors for multi ranges).

Basic circuit goes on a .5 by .8 inch bit of perf board.

Doug Owen