NleahciM:
What’s this PCB for? That’s some serious light output density… Did somebody ask you to build a flashlight with infinity candles output, and this was the closest you could get to that?
A prototype I’m working on. The goal was to put the absolute max in terms of lumens in the smallest possible footprint while making the works able to actually be usable in a practical sense. I figure ~800 lm total @ 350mA/3.4VDC per LED is pretty much the limit for the current tech and packaging.
Oznog:
OddOne: how did you determine you have no thermal problems? Without a proper testing procedure it is very difficult to know what your dies are doing. But high temps will definitely reduce the power output and prematurely degrade the die whether you can see the difference or not.
I have “no thermal problems” in the sense that when I bolt the PCB to an aluminum plate (2" x 2" x 1/2") the temp for both plate and the portions of the Rebels I can get my probe to touch climbs up to ~40-45C in room temp air and with all eight LEDs taking 3.4VDC @ 350mA each, and both temp and light output are stable (as much as my decidedly hobbyist-level gear can resolve such variations) over time. (“Time” in this case being 30 minutes continuously.)
Shy of spending pointless amounts of $ to purchase more thorough testing gear to quantify things more precisely, I’m satisfied with what I’ve been able to come up with and how well it seems to work.