Zombie 803T diode

Well... I built a quick little box style the other day with an open can PHR-803T diode. Just for fun I guess. I had it set at around 120mA. Well, today I changed the lens in it and went to turn it on and it flickered and became an LED on me. I checked the current and somehow it crept to 145mA. No idea how.... Anyway, since it was dead I decided to see what would happen with just a little more current, and suprisingly it lit right back up again  ;D  The beam itself directly from the diode has some weird 'veiny' patterns in it now, and its obviously not as bright but I still thought I would share  ;D ;D

But this does give us a bit of valuable information. ~150mA is too much for this diode to handle. So to live on the edge I would say about 115mA would be the highest I would take these. and not over ~90-100 for a decent lifetime. It didn't even light up all the way for a few seconds before dying. Even my 6x at 280mA lased for about 5 seconds before dying.

This also leaves me with some questions. Since this was an open can, could the spring in the aixiz module have hit something and messed it up? I used the laser for maybe 5 seconds yesterday as a camparison with my 6x and it seemed fine. Then today I swapped the lens out before using it, and it dies. So who really knows?

All I know is that I will enjoy the last bit of lasing that my zombie diode has left, and then lay it to rest with all my other brave, fallen diodes.

EDIT: thought I would add something else that is noteworthy. The zombie diode has the 'yellow' around it, but it also has this weird greenish-rainbow cone stemming out from where the spot would be on the die (since you can see the entire image of the die as an artifact now) pretty cool!

I had the same thing happen at 80ma, so............ I dono what's going on w/ these things.

Worked fine.. Turned it off. Turned it on again later, and it was very weak. I cranked the power to it, and it lased again, but had the yellow around it. Then I killed it.

i also experienced some yellow tints in the beam around my 803. Ive gone through 3 of them that have blown on what seemed to be minimal current and voltage.

cool half yellow half blue hybrid LOL yea i sold eiwed one running at 86 ma he gets it turns it on and blam no bueno por caca now i owe him another should have only given a one time lase warranty :'(
naw I'll make it right ;D ;D ;D

Yellow glow artifact are the result of breakdown of the quantum well structure causing it to emit a spontaneous emission in the yellow green region.

Gus --

I have mentioned this before on here. A BluRay creeps up in current as it warms. That's why my Kryton is at 190 mA.... I set it at 180.

Mike

Hey mike, do you have any artifacts in your 6x's dot? I wouldn't really call them artifacts, but I am just barely barely barely be able to see the edges of the rectangular die under the dot itself. and 190mA holy jeez!!! My 6x starts out at about 140 and creeps to 150.3mA. Maybe tonight I'll take a jump to 170mA  

I don't think the current rise was due to 'creep up' on the PHR. I measured it at 125ish over a couple minutes. I think before I closed the box up, I meant to just turn it down a hair, maybe like 105mA, so I turned the pot a nudge without measuring afterwords. I think I may have turned it the wrong way on accident  ;D

Gus--

It's interesting what you can learn just by playing around like.
Blue,red,green and yellow diodes could be just around the corner. keep up the good work [smiley=beer.gif]

--hydro

What drivers are you guys using? A constant current driver would not allow the current to just change (creep up), unless a component fails.

If the voltage was constant, the current would raise with heat. But since we use constant current drivers, the driver decreases the voltage to keep current the same.


I'm confused...

Well Isn't the lavadrive really the only constant current driver we use here? or is the lm317 also constant current? I thought the other drivers just limited the current.

pwnstar said:

Well Isn't the lavadrive really the only constant current driver we use here? or is the lm317 also constant current? I thought the other drivers just limited the current.

Click to expand...

That is incorrect. All proper LD drivers are constant current. The 317 is a very general cc driver used pretty much anywhere, and usefull for lasers, as long as you have the voltage to spare.

LavaDrive and the rkcstr drivers are also constant current. And there are many other possibilities.


A constant current driver constantly adjusts the voltage in a way, that keeps current the same, even as the internal resistance of the load changes.
As long as the driver has enough voltage on top of what the load needs, it will regulate the current. Not limit it. Once the voltage is so low, that it drops out of regulation, the current will start dropping with linear drivers like the 317. While in regulation, it will alway be the same.

The difference to LavaDrive is, that the current does not start dropping, once the voltage is too low, but the entire driver stops to work. The 317 and the LavaDrive achieve the results in a different way, but they are both constant current drivers.



Anyway, as i said, a cc driver will decrease the voltage, if the load heats up and the resistance drops, and the current will stay the same. With a proper driver, the current can not "creep up".

And this has nothing to do with the type of the diode. A 317 would never allow the current to "creep up".

My Zombie PS3 blueray draws more current as it warms up on an LM317 cc driver powered from my bench supply. The LD gradually needs to draw more voltage as well which means turning up the supply to keep the regulation.....
Run anything else on the same driver and the current stays the same.

There is something about these Zombies that seems to screw with the drive circuit.

Regards rog8811

Hmm, i have two zombie PS3 BRs.. I need to try, but i can't see how this should be possible at all..

When it first happened I spent some time checking out the drive circuit, thinking maybe I had dripped some solder on it and it was shorting out, put a SenKat red in and it worked perfectly, put an NIR on it, perfect.....reconnected the Zombie and the current climbed.......

Regards rog8811

Rog, does your LM317 perhaps say "SG" on it?

Gus --
My 405's (6x) don't appear to have anything wierd in the output other than a somewhat eliptical spot. This is at both 130 mA and 190 mA.

As for CC drivers, I'm using my junkbox LDO CV drivers with a series pot. Works for me ;D

Mike