As I understand, part of the hassle (apart from the very inconvenient electrical connection between the thermal pad and led+ ) is that the variation of performance (output, current capability) is quite large and that you therefore have to buy a bunch of black flats and test them and pick the one that has that great performance.
cool… This one here?
Does anyone make an MCPCB for it?
From this thread here…
“A very annoying feature of Oslon Black emitters is that the led-minus is electrically connected to the central thermal pad. This requires, when the led is mounted on a DTP-board, that the ledboard is electrically insulated from the flashlight body.”
This almost seems unsuitable as a flashlight emitter, where the goal is solid thermal contact between the MCPCB and host….
How do you (reliably) electrically insulate AND thermally conduct at the same time?
You can reliably insulate a DTP board from body with an anodized mounting surface
Aluminum oxide is a really good ceramic thermal conductor with 28W/mK of course not as good as aluminium alloys around 200W/mK
It is still 3 times better than Arctic silver thermal paste
How many did you test before you got yours to do 800lm at 4A? Or did you just get lucky?
Yes, there are some things to think about. I would try to use this LED in a light with multiple batteries in series and a buck driver (it has a very high Vf). Some of these lights have reversable battery carriers where both the minus and the plus contacts are on the same side. This means that there should be no current flowing through the body of the light. In that case there is no need to insulate the LED. Otherwise one could use a non-conductive thermal adhesive (or a paste and plastic screws). High quality thermal pads are another option. Also there a some drivers where the minus of the batteries is connected directly to the cathode of the LED. In that case it also wouldn’t matter.
You can use standard PCBs for XP-LEDs, just use less solder and press down the LED. The solder pads of the Osram are a bit smaller.
@djozz: unfortunately, yes. The problem seems to be that not all of the samples have the same thermal resistance (at least this is my guess). Not all of the still get brighter at currents over 3 or 4A.
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