Power regulation for 5 LED headlamp?

[**DONOTDELETE**]

The application is a Petzl Zipka that starts out with 3 White LEDs. I was planning to mount 2 more LEDs in the housing. I'd like to be able to vary the light output from low to max (20mA) via potentiometer.
This lamp is very small, so a couple of small (TO-92) components could fit, but unfortunately not the LM2621 evaluation board.

Which reg should I choose?
LM317L Voltage Reg or LM334Z Current Reg? If it's the 334Z, how do I obtain 20mA of current?

I've taken a couple of EE classes and forgot most of it. What you guys could help me with is component selection and a simple schematic. I'll document the conversion for the greater good.

Thanks, Greg

 

[remuen]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by meboe:
The application is a Petzl Zipka that starts
Which reg should I choose?
LM317L Voltage Reg or LM334Z Current Reg? If it's the 334Z, how do I obtain 20mA of current?
<HR></BLOCKQUOTE>

I just saw your thread by accident. You should switch to the LED forum in which this issue discussed in different threads as eg.
http://www.candlepowerforums.com/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=3&t=001484
http://www.candlepowerforums.com/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=3&t=000983
http://www.candlepowerforums.com/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=3&t=001221

When using the CPF search function you will find a lot more about boosters/regulators/DC-DC converters ....