Luxeon III Bin Codes

[psab keel]

I just wanted to share something that may interest some of you concerning Luxeon Star III LED's.

After doing extensive testing and consulting with my stepfather who is an electrical engineer (who appropriately works for I2 Systems -who make LED systems) I came across some interesting information concerning overall LED life and run time. He said that after working with one particular high powered LED, Seoul or Lux, and running it at slightly over its rated current, the LED blew in 4 hours.

I was originally running my BIN 1 Cyan LED with the general LED voltage drop as outlined on the Lux III datasheet 3.9 V to be exact. But curiousity got the better of me when I did some reading on the BIN code Application brief. Now like most of us, I paid little attention (other than when I discovered the massive difference between Color BIN codes concerning Blue and Cyan. Just ask Corbin.)

What interested me was that the Lux III's are also binned for Forward Voltage Drop.

eg. On the back of a

Cyan Lux III

SJ1C 00354
IIijieinc LXHL-LM3C

S - is the Flux BIN
J - is the Forward Voltage BIN
1 - is the Color BIN
C - is the Color code


When looking at AB21 (Binning Application Brief) J- BIN has a forward voltage drop of NOT 3.9 which is the average Vf, but has a Vf in the range of 3.27-3.51.
So in effect in order to properly calculate when using a resistor and your power source, you have to check the BIN code on the back of the LED.

So I was overpowering my LED. I don't know if this really concerns many of you out there. But I personally build my sabers to last. I don't want to ever have to build new ones, or replace all kinds of components every few years. I want my LED's to last their rated overall life or longer. I know some of you have read me in other threads making the point that by running your LED at less than your max ratings you exponentially prolong the life of the LED. I personally would rather have a saber that may not be as bright, but lasts me much longer overall. Another advantage to running your LED at less than max power is that you increase your battery life and thus give yourself more "playtime.

As I said, this may not concern many of you, but for those who would like their saber to last them a really long time, this information may be of use to you.

[Novastar]

Psab--you're in some ways absolutely right!

You can indeed burn out an LED by running it even SLIGHTLY over its rated "max continuous current" for a long period of time (long as in hours).

An LED may "light up" even when below its forward voltage... although it may not be very bright. You are right to assume that, if you have a choice, it's best to give the LED just under its "max cont. current", because it has been tested to survive for that and below... for a long time.

This is essentially what companies with all kinds of parts do. They do rigorous tests on 1000s of parts and see what the "average joe" part can handle. How long it lasts, what kind of stress it endures. What is exactly "too much", what variances, etc.

It's unlikely that an LED ever runs "exactly" at spec, but--you can bet your bottom dollar that there is NO reason why a company would sell an LED, rate its max cont. current at X... and then set itself up for failures and returned materials, etc.

1540ma is the max cont. current for a Red-O Lux III--according to Lumileds. That means you're free to feed it that current CONTINUOUSLY for long periods of time (i.e. a few hours) while properly HEATSUNK (sunk?, lol)... and/or you could give it <1540.

1541 might kill it in a few hours (maybe).
1600 might kill it in a half hour (or worse).
1700 might kill it in a few seconds!

Then again--everyone is free to push the suggested limits as they see fit. For $8 LEDs... for some, it's more than worth it. For others... it ain't. You are right that "blowing out" an LED is kind of silly... whereas reducing a 100,000 hour lifespan to 50,000 is no big deal.

If you had your saber on 24/7/365...
(100,000 / 24) / 365 = 11.4 years

I don't know of a single person out there who would do such a bizarre thing. I mean... you'd simply be UNABLE to do this anyhow--without having your saber hooked up to a wall outlet. And WHY you'd want to run it with *ZERO* stops in usage... is beyond me. Besides, that might actually burn it out.

So... if you had your saber on... for FIVE HOURS a day... 7 days a week, 365 days a year...
(100,000 / 5) / 365 = 54.8 years

Um... so I don't know about you, but... burning LEDs out isn't THAT big of a deal... :) 50 years from now... I'm positive I will either no longer have the sabers I have... OR I will have changed the LEDs and drivers SO many times... that...

...I'll never even remember answering this post, my friend! :)

[psab keel]

Hey Novastar,

You do bring up some very true and interesting points. :)

I just wanted to share my find with anyone who may be interested, and as I said, it's really a matter of personal preference.

Man, I think of the days before Luxeon LED's and how far the technology has come. It's so nice to be able to build sabers with duelability, brightness, sound, true colors, and at a fraction of what they cost in the days of plasma and el.

I'll be posting pictures of my latest sabers soon.

Thanks, Psab

[psab keel]

For those who may be interested, here is some more information straight from Lumileds Datasheets and application sheets that may shed some light (sorry, I couldn't resist!) on getting the most out of your LED's.

This information is specific to Lux III LED's:

Average Lumen Maintenance Characteristics
Lifetime for solid
state lighting devices (LEDs) is typically defined in terms of lumen maintenance
the percentage of
initial light output remaining after a specified period of time. Lumileds projects that white, green, cyan, blue, and royal blue
LUXEON III products will deliver, on average, 70% lumen maintenance at 50,000 hours of operation at a 700 mA forward current
or 50% lumen maintenance at 20,000 hours of operation at a 1000 mA forward current. Lumileds projects that red, red
orange,
and amber LUXEON III products will deliver, on average 50% lumen maintenance at 20,000 hours of operation at a 1400 mA
forward current. This performance is based on independent test data, Lumileds historical data from tests run on similar material
systems, and internal LUXEON reliability testing. This projection is based on constant current operation with junction temperature
maintained at or below 90°C. Observation of design limits included in this data sheet is required in order to achieve this
projected lumen maintenance.


Layman's Terms:


So that means that if you run your LED at 700 mA for 5 years it will be about 70% as bright as it was when you first wired up your saber.

Conversely if you run it at 1000 mA for 2 years it will be 50% as bright as it was when you first wired it up.

Running a Red, Red-Orange, or Amber Lux III at 1400 mA for 2 years it will be 50% as bright as when you first wired it up.

And according to the Luxeon e-mail Newsletter:

LED Myth

Myth: Power LEDs that claim they can be driven at 1A are usable at 1A.
LUXEON Fact: When most power LEDs rated for drive currents of 1A are actually driven at 1A, thermal management becomes prohibitively difficult. Ultimately, the maximum junction temperature that must be maintained to ensure lumen maintenance lifetime is exceeded.

And everyone knows what heat does to an LED over time. POOF!


I just want to share this information with those who may be using resistors for their Lux III LED's and those that want to have their light sources last as long and stay as bright as long as you can get them to. I know this may not concern many, but I know that I don't want to have to replace all my electronics every year or so. I want to replace mine when my LED has been running for about 5-10 years. That would be awesome!

[BhujangiJedi]

Think about where lightsaber tech was five years ago... and where it is now. Tech that is awesome right now will likely be snickered at (or remembered with fond nostalgia) in 5 years.

I've seen some seriously awesome sabers on these boards and I don't know how difficult they are to take apart, but if better LED tech comes along, you can bet I'll spend the 30-90min taking apart my sabers (admittedly simple ones) required to swap it out.

Here's Lumileds' PDF: Luxeon Binning & Labeling (http://www.lumileds.com/pdfs/AB21.pdf)

In case there are any readers who don't really follow:
You don't really need to worry about any of this if you are using the recommended 700mA or 1000mA buckpuck for your LED. If you're using a resistor, it's good info to look into. The general specs for LEDs give a range of forward voltages - the bin number gives you a tighter range. To really get exact, you can test with a variable power supply.

The lifetime expectancy is also worth considering if you're using a driver board that allows you to overdrive the LED.


With all the variations in componenets, how tight can you really get? Do batteries really give 1.5V? What's the variance there? How quickly do they drop off? Do rechargeables give 1.2V? Variance? Drop-off rate? And then the resistors have a 5-10% variance. Ah well... hope I'm not frying my red-oranges & ambers (bins F, G, H; Vf 2.55 - 3.27) with 4xAA NiMH and 1.2O resistor.

[acerocket]

I have a 15V 3A power source (adjustable with digital readout) that I use to test all my LEDs before putting them into service. It is really amazing to see the difference in voltage the LED is wanting at 'peak' amperage. I recently used 10 blue Lux III LEDs run direct drive and they were consistently.6V under the published value. Had I used a resistor based on the published voltage, I would have been overdriving them quite a bit.

[psab keel]

Like I said, this information may not interest many here, but I thought it might be worth sharing.

You folks do bring up some very valid points as well.


: )