The current sense feedback is on the negative side of buck/boost drivers, to my knowledge. This is baaaad news. For the love of g0d, why have those @#$%ns chosen the cathode slug as the main heat sewage? They just weren't thinking in flashlights at all, which I can understand, but it could also have implications for “integrated” drivers. 
Of course, just an opinion. Time for BeO/diamond dielectric MCPCB's fellows. 
Cheers ^:)
My MCPCB is designed for prototyping purpose. It will accommodate various optics and mounts - that’s why it’s big and thick without pre drilled holes. The design makes it easy for various testing, I can mill it down to circular 20mm or any shapes without risk to short any electrical traces because it’s shorted anyway.
To make it electrically neutral is EASY. You just put any commercially available dielectric tape/epoxy/glue between the MCPCB and the host. The heat concentration already spread to area 95 times the cathode size, less delta T. Even if we use dielectric material with only 3W/m.K (thin layer of course) thermal conductivity would still theoritically superior than those LED with thermal pad. The cathode makes metal - metal contact through copper and solder connection, less thermal resistance than through dielectric - solder connection from the LED thermal pad base. Unless the base of those LED with thermal pad is made from material with thermal conductivity superior than copper this design would be better for high power LED. But I can’t be really sure until mr Djozz done with his back to back test.
The best test is to compare it to XHP50 with equal sized DTP board.
I can add the XHP50 test to the graph for comparison 
The package is on the way to Maukka, should be there in a week. I added extra bare NV4 emitters from each type for you. There are total 13 emitters including 3 pcs NVSL219CT R9050.
PACKING LIST
——————
2. NV4W144ARE (12V) - sm575E1000Lv9R9050 - 1 pc
3. NV4W144AME (6V) - sm575E1000KR9050 - 1 pc
4. NV4L144ARE (12V) - sm305E900Lv9R9050 - 1 pc
5. NV4L144AME (6V) - sm305E1100KR8000 - 1 pc
6. NV4W144AME (6V) - sm653E1200KR70
soldered on VirEnce DTP MCPCB - 1 pc
7. NV4W144ARE (12V) - sm575E1000Lv9R9050
soldered on VirEnce DTP MCPCB - 1 pc
8. NV4W144AME (6V) - sm575E1000KR9050
soldered on VirEnce DTP MCPCB - 1 pc
9. NV4L144ARE (12V) - sm305E900Lv9R9050
soldered on VirEnce DTP MCPCB - 1 pc
10. NV4L144AME (6V) - sm305E1100KR8000table(table#posts).
soldered on VirEnce DTP MCPCB - 1 pc
11. NVSL219CT - sm305D200L1R9050
soldered on SinkPad DTP MCPCB - 3 pcs
TOTAL: 13 ITEMS
Thats a lot of work to test^ but can’t wait to see them!
Correct, given that emitter testing the way I do it (no automation whatsoever, which is labor intensive but also adds to the accuracy) takes several hours, and that I have a job and a family, I’m sure that I do not have the time to test all 13. But I will pick the emitters that will tell enough about the others that a complete picture can be derived.
I wish I live closer so I can bring the beers and coffee. Yes, I just need them all spectra tested by Maukka. Djozz only need to crash test any LED of his choice. As my/our gratitude to them, they can share the pre production Nichias (if Djozz haven’t kill them already …. 
)
Nichia’s are tough leds, hard to kill, but I will give killing a go for at least one, my PS goes up to 20A if needed
I hope you only kill the R70 then….
The rest have very nice colour. Perfect drops in for many flashlights
I really look forward to check out the results of those 4000-5000K R9050s.
Gonna be exciting to have torches with 1K+ continuous operation Rolls-Royce luminous flux.
Cheers ^:)
How does a 0,04 °C•cm2/W thermal resistance with 17 Watt/m•K thermal conductivity appeal to you?
It’s far lower than the thermal resistance between LED die - solder point
Uhm…
Judging by the way you say it, it’s probably pretty good 
I’m not familiar with those technical terms and units.
But i gather it’s better than the usual ‘seal pads’ used for power transistors etc.
Now the question is; #1 where can we buy the new Nichia LEDs? #2 Where can we buy FujiPoly XR-m?
I plan to buy one full reel (3500 pcs) of them for my near future project. That's why Nichia sent me several samples to test. Nichia is very strict about MOQ to me, It doesn't even let me buy 500pcs. 
It will be available in Q1 2017. Still waiting for my Fujipoly..... ;)
Wow, a full reel? Gonna open some e-shop? :???:
Hope you'll be getting some R9050s. :-)
Cheers ^:)
The plan is to use only the 3000K and 5700K. Yes, the 9050 is my target. If I needed lower CRI, I would go with XHP50 instead, easier on thermal design. No, it’s not for an e-shop, I have residential & shop display lighting projects here. But why not? if I could get some extras from bare emitter sale online, then I’ll do it.
Still working to get less than 500 pcs though.
If you could get some in ~4500k I would grab some for sure (assuming they work good after testing). 3000k is a bit too warm for a flashlight and 5700k a bit too cool. I have come to the conclusion that 4000-5000k is my personal sweet spot.
Obviously this is only if you could get a few extras tossed into your order (I am sure others would buy as well), I do not even remotely expect you to change your planned tints.
Let’s see if I can get mixed CCT with the same MOQ =)
If you could mix the tints a bit I am positive there would be some level of demand for some neutral tint versions with high CRI. How much only depends on the results from testing.
If Djozz could manage to keep a 12V 5700K one alive, i’d be very interested.
…actually also very interested in a 3000K one… 
(but i’m probably not the only one…)
[edit]
6V is fine too.
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