3W U-bin similar to a 1W S-bin @ 350mA??

I've been thinking about those rare 1W S-bins.

Looking at the output of an S bin (51.7-67.2 Lumens) vs a U bin (87.4-113.6) we can see that the output of the U-bin is approaches double that of the S-bin.

I has also been shown that the Lumen increase is not proportional to the current increase (i.e. 2x current does not yield 2x Lumen output). In a likewise manner, the emitter becomes more efficient as the current decreases.

I have noticed that Vf drops by about a quarter of a volt (or about one bin) when a 3W emitter is driven at 350mA instead of 700mA.

So, ignoring the effects of color-shifting due to current dimming, a 3W U-bin could likely be used as a substitute for a 1W S-bin in a pinch.

Any comments (other than why waste a good U-bin on that! )?

Paul

Yes like you said. Other than the LuxIII having a lower Vf when under-driven at 350ma and color tint shift, they are about equal.

Other than that the LuxeonI won't see the same increase in lumens as the LuxIII will past 700ma.

Check out this link to see a comparision of a U-bin under-driven.

Ah yes, Isaac. I forgot about that post (I had even subscribed to it! ). So I wonder if there's some creative marketing going on at Lumileds.

Paul