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FrozenGate by Avery

** BluRay Diode GB **

I popped my 1st BR.. Was measuring the the mA with a DMM and the wire came loose for just hair of a second, then the light went out. It's strange when the lasers die. They still draw the amps. And I could have sworn I measured no volts too, unless the crack kicked in. But anyway, my 2nd BR just starts to lase at 39mA. Kind of high compared to my previous one. I wonder if I caused trauma desoldering the PCB from the LD, seems like a reasonable explanation.
 





Just had some thoughts on this wrt the BR LDs.  There are some benefits to using both the iternal PD and the external ones.

For the internal one, the PD current is going to vary for each of the LDs (Red, IR and BR) - the feedback mechanism would have to compensate for that, however, you would get the best protection for the LD "group".

Using the external PDs would allow for the LD power to be modulated to compensate for losses in the optics and actual media (dirty discs).  

I would think that the ideal method would be to use the internal PD for absolute power limiting to each LD and the external PDs for normal power modulation.

Daedal said:
[quote author=IgorT link=1189562336/540#554 date=1194469746][quote author=Daedal link=1189562336/540#553 date=1194463668]Not particularly... The PD inside the diode is a better option... just connect to that (as does the PS3) and you can limit the output based on the PD output. This can easily be done with some transistors... ;)

--DDL
Click to expand...


If the current regulation would be handled by referencing it to the PD, this would be all the regulation needed, right?


This would be the perfect circuit for the BR. But it would need some safeties. (max current limit to prevent this same regulation from killing the LD in case the efficiency drops too much)[/quote]

Igor, Photo Diodes work by generating some current based on the light incident on them... it's like a photocell. The feedback (this current generated) would be based on the light output of the LD itself... and thus no calibration would be needed aside from actually setting the amount of current pass based on the PD feedback... There is no better calibration method that I am aware of...  :)

--DDL[/quote]
 
Makes sense Chimo :)

Sam Goldwasser did an extensive test on the whole lens assembly... and given the many surfaces the diode has to go through before it gets to the disc and then come back... at 5mW the power going to the disc was only 300uW... ONLY! :o

So... this really corresponds with the measurements that the diode was meant to be driven at 15 or so mW, but at pulsed... I believe the diodes are meant for 20mW pulsed operation... and for a reader, that's quite a bunch ;)

The external PD's are arrays... and I thought they were used to pick-up the data from the disk? They could also double serve as a means to further fine-tune the power to the diode :)

--DDL
 
Daedal said:
The external PD's are arrays... and I thought they were used to pick-up the data from the disk? They could also double serve as a means to further fine-tune the power to the diode :)

--DDL
Click to expand...

That's their function, however, I don't see a problem with them doing a dual role. :)

Cheers,

Paul
 
IgorT said:
[quote author=yes8s link=1189562336/540#547 date=1194445210]I guarantee you it is still lasing...but the lasing threshold has been raised. Like i said it's strange but I guess i'll have to see how long it lasts. I've been running it at 55mA now for two days and it seems fine.
Click to expand...

What happens if you go from the 9V battery back to the lab PSU? Does it return to the old behaviour, or does it stay the same?[/quote]

9V or PSU still the same behavior. I have been pushing this diode a little now and it has turned into a freak ;) ;) I pushed it to 95mA - it worked and is still working. At that power I could see the beam in the dark with no fog or anything. I am now running it with LM317 + 22ohm = 56mA's and it it still going.

I used the smaller brass Aixiz module and it does heat up a little after about 30secs so I'm just duty cylcing it abit.
 
i was just tinkering with what i thought were dead diodes o my new regulator and to my surprise it light really nice up nice. i pushed the the little bad boy all the way to 150 ma :o :o the highest the regulator could manage and it still could be pushed further.

this one is pretty messed up but it was definatly lasing. it was one of my first attempts to drive a blu-ray and i crushed the diode in sideways while trying to fit it into an aixiz module so fitting it into the aixiz module was an imposability but it was still pretty cool plaing with the floresencs of the bare diode ;). this is a diode from a ps3 from about 4-5 months ago and it held up pretty well after being thrown in a bag with other random parts form the ps3 and handled with no care at all. these things are pretty resilent.

oh yea and i love the blu-ray color it is soooooo cool ;D

Thanks,
Mitch
 
Zarniwoop said:
I'm curious - did you have a cap across the diode, or was it on your driver?
Click to expand...
My cap was on the driver. :( Wires lead out from the driver to the LD, and that's where I was playing. I think I need to get me some alligator clips.
 
drlava said:
[quote author=marks47 link=1189562336/555#567 date=1194586772]

He's saying 150 ohm in series with a 9Volt... 60 milliamps... Geez... He almost deserves to fry it.
Click to expand...

*BUZZZZZ* wrong.  with the 4.8V diode drop, 9.3V battery, you're looking at 30mA which is about right on for 9mW.  Needs a capacitor, though.[/quote]

Ugh. I did it again. Sorry.
 
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