Yes, to me also it looks like XHP35.2 is flip chip with wider core gaps. :person_facepalming:
XHP50.2 is throwier than XHP50 in terms of cd/lm because of closer dies.
XHP70.2 is floodier than XHP70 in terms of cd/lm, but throwier in absolute cd/mm² because of higher output.
Here we have flip chip. With wider spacing. Not much more output due to increased efficiency. No output increase due to better thermals.
It certainly looks like a downgrade for our needs……but we’ll see.
Noticed one more thing…on the table says “XHP35.2 (12V)” and “XHP35”. In interpret that as saying that they don’t need to clarify voltage of XHP35 (because, as we know, it’s always 12V), but they need to do so for XHP35.2.
So probably there will be a 6V variant. Maybe 3V as well?….
Good points. I can imagine that it would be almost impossible to design it so the dies can be in series or in 2s2p config without making the space bigger between those dies.
So they would have to make 2 different ‘xhp35.2’ chips (where the dies are close together) to have xhp35.2’s with different Vf.
BTW, today I realized we don’t know the die sizes. They may be smaller which would explain price reduction and only small marginal gains. Just like Nichia 219D….
I believe the way the original xhp35 was built was the 4 dies were butted up to each other positive to negative to make then all in series.
I don’t see any way around having a tiny gap if you wanted it to be 6v and 12v.
Now if they were willing to make 2 versions, one 6v and one 12v, they could probably keep them close together. That would cause a ton of complications, though.
This is me guessing, I don’t really know how the base is constructed, etc… Maybe someone can chime in who knows more.
Agro. I didn’t say that with a 2s2p setup the dies couldn’t be together. I said that
I can imagine that it would be almost impossible to design it so that the dies can be either in series (12v) or in 2s2p setup (6v) without increasing the gap.
If they choose to make 2 separate versions both dies can be as close together as they are now. But that would probably not be very cost efficient.
Doesn’t seem like much progress in the XHP35.2 especially with the larger separation, which means possibly no XHP35.2 HI variant. I alwasy wonder what’s the purpose of the XHP35 HD when there are already XHP50.2 and XHP70.2 that are brighter and more efficient.
Yeah, it’s the biggest die with the most output using a 3.5mm pad. So if you have a street light full of xpl, it can be easily swapped to xhp35 and you get way more light from the same surface area. That’s how I understand it.
BTW, none of these leds are made for flashlights, they are more for street lights and commercial stuff.
I have a small 1x18650 Zebralight that uses the XHP50.2. I also have a larger 4x18650 light that uses the XHP70.2.
Those LEDs aren’t used much in budget lights, due to their 12v forward voltage (and thus requiring a boost driver or several cells in series), but they’re becoming popular for high-output flashlights.
there is no problem in arranging the dies of the original XHP34 to make 6V but they did not make 2 versions, so there is only 12V
they would need to rotate some dies and do the bond wiring differently