Nichia E17A/E21A series (April 19th: updated with output tests in the OP)

Based on my thoughts above, I think I came up with a good MCPCB design for good heat transfer from the non-DTP LED contact. Start with a copper disk or sand off all the insulating stuff on a copper MCPCB. Then put down some Kapton tape covering all the area except for the DTP area where the LED cathode will connect. Cover all the Kapton tape area with copper tape; this will be the other LED contact. I have some copper tape that is 2-3 thousandths of an inch thick, which is about 2oz thickness. I made a mock-up of this design on a TPAD MCPCB; see picture.

The copper tape is electrically isolated from the bulk copper below. The Kapton tape doesn’t have very high thermal conductivity, but is very thin, about 1-2 thousandths, which is about 3-4x thinner than the dielectric layer on MCPCBs, by the look of it. When the Kapton tape is spread out over a 20mm MCPCB the extra thermal resistance is only about (40microns)/[(300mm^2)(0.12W/mK)]=1.1 K/W. This should make for good thermal transfer away from both LED contacts. I tried soldering on the copper tape, and the copper tape adhesive got a little soft when everything was at soldering temperature, but once it cooled down it stuck well again.

The Sinkpad has a way better heat transfer from the outer solder pads than Noctigon

if you look right the positive and negative side go all the way over the star like a bar between the 2 wire pads
it looks pretty much like your self made star cut to half width

maybe someone makes a board with insulated base and 3 DTP pads insulated by a dielectric

That would work well, but I doubt someone makes it.

I estimate that, in my design above, the bottleneck is the thinness of the copper tape. Heat will have trouble traveling laterally. Using ~1mm copper shim instead of the tape should greatly improve the lateral heat transfer.

It’s done already. 144A and E21A are exactly what the new VirEnce board all about. Only one problem left: $$$$
Until then, Djozz board is your best option. It has very large copper pour for its size and thick copper base. One problem for extreme BLF application is the dielectric used is only 3 W/MK.
A single E21A can be driven really hard > 3A on Djozz board. His last test showed that 144A with 4 times the heat performed OK.

- Clemence

I’m planning on a quad configuration, though.

You can do that too….4 pcs in a single row. Just scrape the masking paint. But, no real use in most FL

Great posts, Clemence! Very nice job you did there with handling these tiny tiny LEDs.

Wait later until Djozz come with his E17A. I myself is rather not to deal with them

:+1: :beer: I like that tests…

Waiting for Djozz’s test results ……drum rolls……

Yes, me too :frowning:

I have have received the leds and reflowed them (both 5000K R8000) on my boards (on which they are going to be tested until your boards will be available), but I need 2 hours for the actual tests, and 3 more hours for the write-up. I’m not sure where to find those hours in the next week.

Very nice! Take your time, we’ll wait for your test result later.

- Clemence

April 19th: I updated the OP with two output tests on my 119 boards.

Thanks for the test Djozz,
Mine was dying at 8A, but still lit. The damage pattern truly depends on how the pads are cooled. The burnt always started from the hottest point. This LED should create a better nice beam pattern with it’s rounded rectangular hotspots.

Thanks for the tests. I cancelled the order I had placed after I saw that the dies didn’t extend to the edge, and I’m glad I did. These might be fine for some applications, but it’s not what I was looking for.

Thanks djozz. Nice testing as usual and invaluable information you have given us. :+1:

Thanks Djozz! You are the best.

SM503 D220 Ra9080 test result. Not accurate but should give you an idea

Complete test link: https://budgetlightforum.com/t/-/45807

Since Virence Shop closed made same design 20mm MCPCB for E21A leds. All we have to do is to order at some online MCPCB service ;))