# DVD red laser diodes max current



## robk (Apr 12, 2007)

Has anyone determined what the safe maximum current is for a typical (?) red LD removed from a DVD writer? I'm running 200mA, pretty bright, burns things. That site that started it all suggests 350mA with a conservative duty cycle. I've blown a couple and I really don't want to blow any more because of the expense and the work involved in removing the diode and remounting it in a brass housing. Any ideas?
Thanks,
Rob

PS- I have seen the data sheets that say typ. 150Ma, Max 200Ma, but I'm more interested in "real world" figures, from those brave souls who push it to the limit!


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## Hemlock Mike (Apr 12, 2007)

Robk --

I have 2 DVD reds running at about 300 mA. They do heat up but I don't need to run them long. A bunch of us will know more when the power meters arrive !! In fact, as I recall one runs at 340 mA !! I haven't had time to try one of my HL6545MG diodes yet but the 18x DVD's are hot !!
How did you make toast of an LD ?? What current ?? Did you have a capacitor across it ?? What driver ?? So many questions..... Any number of conditions can blow an LD --- even static and loose connections causing surges.

Mike


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## robk (Apr 12, 2007)

Thanks for the reply. The first one I blew was on a bench power supply, I had no idea what I was doing, brought it up to 500mA and poof. The one I'm running now is using 6V battery supply, LM317 used as adjustable current source set by a 20 turn pot to 200mA, caps before and after the 317 - on the output side a 33uf tantalum and a .1uf ceramic and a 1N4001 reverse voltage protector. I didn't realize these things were so sensitive and unforgiving. Now I take anti-static precautions and really clean up the power supply - no spikes, transients, etc.

So you think I could bring this thing up to 300mA once in a while? The button supplies 200mA, the slide switch 100mA for alignment, and just playing with no worry about blowing up. 
See:
http://www.tomokadesigns.com/laser.jpg

Rob


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## Hemlock Mike (Apr 12, 2007)

Robk-

You are safe at 200 mA it appears. I don't know which diode you have and they can all be different. I have run some to 350 mA but with good heatsinking.
I don't advise to go up because you may have something I don't know about. A watt meter would help so you could watch for an output plateau or something warning of DOOM !!!

Mike


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## robk (Apr 12, 2007)

I hear you! I better play it safe until someone organizes a group buy and I can get a few spares.
Thanks,
Rob


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