<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by lambda:
How well everyone likes the square beam spot will interesting.........<HR></BLOCKQUOTE>
Ahh - simply perfect for my pocket 35mm slide shows
Gee, lambda, you want us to answer the questions in the thread you started?
I can partly address your question. If you are using the MAX167X based stepup, be aware that the manufacturer's absolute maximum output voltage is 6.0V. Depending on the characteristics of the particular 5W luxeon you have, you might not be able to stay under this voltage, even underdriving it as you propose. If price is no object, I would be tempted to use the 5W device as per the currently available datasheets it should offer better efficiency. As to the question of junction temperature, the thermal resistances [junction to PCB] of the 1W and 5W devices are 17 and 11 C/W respectively. This difference is negligible for your plan of operating at only a watt or so.
