>I have a specific prospective application in mind for my own use (4v to 12v
>converter for FET gate drive) but this is only one of many possible
>applications. I also would like a low cost, compact, efficient white LED
>driver that provides essentially constant output and reliable starting over
>a full range of single cell voltages (<0.9V - > 1.5V)

I use an LT1930 for these.  Pretty cheap, whole circuit fits in about 1cm
square, VERY clean output.  2.5V to 15V input, 2.5 to 25V output, 1A input
current limit.

With a little ingenuity (op-amp across a shunt), you can use it as a
constant-current source as well.

Use the circuit from their proto board rather than the data sheet.  It's
cleaner.

Andy

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Race Boats  - andy@RC-Hydros.com      http://www.RC-Hydros.com
Airplanes   - andy@FlyingHobbies.com  http://www.FlyingHobbies.com
Electronics - andy@MontanaDesign.com  http://www.MontanaDesign.com
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