Luxeon Star question: why lower voltage?

[chetvaldes]

I'be been meaning to ask this for a while:
Why does the Luxeon Star seem happy to run at lower voltages (I'm specifically talking about the white version here) than conventional LEDs? This would suggest some different chemistry or physics going on. Anybody know?
Chet

 

[**DONOTDELETE**]

First, consider that in some cases, we are talking about using special circuits which boost voltage. Without such a circuit, there is no way, for example, any white LED could be driven by a single AA cell.

Second, quantum physics defines the threshold voltage at which the LED will "fire". This voltage is dependent on the LED's color, which in turn is dependent on the junction chemistry.

In the ideal world, true blue LEDs require only 2.29 volts, whereas green LEDs only require 1.76.

Makers of white LEDs have, in the past, tuned their LEDs so that they fire mostly at the blue level, which makes their LEDs appear brighter.

However, the white, green, blue, and cyan Luxeon Stars are all built using indium gallium nitride, which implies that a white LS may actually fire closer to the green level.

This theory may be supported by the fact that the LS produces a "warmer" color than other white LEDs.

 

[MrAl]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Duggg:

Second, quantum physics defines the threshold voltage at which the LED will "fire". This voltage is dependent on the LED's color, which in turn is dependent on the junction chemistry.

In the ideal world, true blue LEDs require only 2.29 volts, whereas green LEDs only require 1.76.

Makers of white LEDs have, in the past, tuned their LEDs so that they fire mostly at the blue level, which makes their LEDs appear brighter.

However, the white, green, blue, and cyan Luxeon Stars are all built using indium gallium nitride, which implies that a white LS may actually fire closer to the green level.

This theory may be supported by the fact that the LS produces a "warmer" color than other white LEDs.<HR></BLOCKQUOTE>

Duggg:
Do you have any data on the LS's forward
current vs voltage? or do you know any
place on the web to get it?
or did you make any measurements?

Thanks,
Al