6x 20mm XML-ledboard comparison

[leaftye]

@welight

@Hikelite

@djozz

Looks very promising but, as usual in marketing, the 'old' type board is drawn to perform worse than in reality; the heat when entering the aluminium core of the board will go circular in all directions, not just downward, as the drawing suggests.

In any case, I think the major bottleneck was already overcome by the direct-bond-to-copper-boards, I do not expect a performance improvement as high as when Sinkpad boards entered the market. But the electrical insulation between thermal pad and core is a really useful feature!

Exactly!

All Copper boards can be enhanced to distribute heat better (not really needed), like all AL normal boards have the thermal trace as wide as the boards. For some reason on direct thermal path they decided not to them like that.
I do not see them actually work better than direct thermal pad boards which clearly cannot take advantage of the 390W/m.k of the cooper when you can see Aluminum boards rated at 135W/m.K performing as the 390W/m.K copper boards.
So what I mean that wide spread can be done with normal copper direct thermal path, especially for single LEDs on 20mm.

The reality is copper as a base substrate has better thermal performance than ALU. The issue has always been the dielectrics which are generally high in fibreglass are the issue and direct thermal pads make a big difference. This is more an exercise in replacing the dielectric to make ALU boards a better performer relative to copper as ALU is a lower cost product. I have some initial samples of a multi led XML PCB, happy to donate for test?

That sounds great. Either djozz or relic38 would be great. Djozz didn't mention it in his post at the top of this thread, but he also stress tested a direct bond copper mcpcb for the Cree MT-G2. I think it'd be great if you could send samples to both testers if they're up for it, especially of that multi XML board since that may offer something that no one else does.

The graphic is a bit disingenuous, but it's minor compared to the results of independent testing. If the results are good, I'll be posting the test results in this forum and at least one other, not that misleading graphic.