Hi , this looks very impressive. Since I plan to do something similar I would be very interested in your schematic. From your above explanations it is not clear to me how you achieved the current limiting to protect the HP LEDs. Would be great if you could post your schematic.
rudy12
Rudy.
On the fifty watter, I used a current limiting circuit I'll link to below.. Though I only used that circuit because I needed three amps. Pretty much otherwise, I am using LM317 connected as a current source set up after another LM317 set up as a voltage regulator. In that configuration, the lm 317 circuits are the easiest and cheapest up to an amp.. Under a dollar for the whole voltage/current regulator circuit. Granted that this isn't the most efficient circuit.. But I am not really all that worried about efficiency.
Finally have the fifty, the ten, and eight three watters all going, for a total of 84 watts. The fifty gets its own MOSFET, and the rest run from 12v and are all being switched by another one.
I'll post some test shots later, as well as do some math regarding guide numbers... But for photographers out there, here's a start:
Black field, reflective subject 25% of field, f1.4 50mm at a distance of 3 meters, illumination period (flash duration) of 1millisecond..... Heavily overexposed at ISO100. I needed to stop down to f7.1 for a reasonable exposure.
That is a peformance level that rivals low to midpower Xenon.
