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24W blue laser help?

AMooMooCow

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So i have teh 24 led module then do i just hook up to a car battery?

just kidding. I have a brand new 24LD A140 casio module, and I was wondering if anyone could help me disassemble it without destroying it. Casio obviously knew people like us would attempt it, so they put some sort of tamper-resistant fastener right where it would stop me.
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If anyone has experience with this thing, how do you like to remove these? I hope I don't have to sand it off with my (cheap harbor freight) 'dremel'.

Also, once I'd get it open, would this circuit work in real life? I know it can function with one diode and multiple sources with enough damping just to be safe, but could I really connect 24 diodes in parallel with multiple sources? Is it safer to build a circuit with the sources in parallel and the diodes in series?
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Pman

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Are you sure that you can parallel all those drivers? I was under the impression that you really shouldn't parallel drivers for some feedback reason or a slight mismatch could cause issues but I could of course be wrong. Took me a moment to find the bottom row anode connection as I thought you didn't have one.
Wish I could help but I can guarantee some people know the answer to this. There is just less members lurking on the weekend.
 

AMooMooCow

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Are you sure that you can parallel all those drivers? I was under the impression that you really shouldn't parallel drivers for some feedback reason or a slight mismatch could cause issues but I could of course be wrong. Took me a moment to find the bottom row anode connection as I thought you didn't have one.
Wish I could help but I can guarantee some people know the answer to this. There is just less members lurking on the weekend.

I believe the mismatched feedback problem is only a problem when the output is a voltage instead of a current. It would be different if the feedback was a current instead of a voltage
 

AMooMooCow

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Oh, I'm sorry. I just realized that the fasteners aren't even in the way. The heatsink is cemented to the diode module. Any way I can separate them?
Edit: alternately, if anyone knows the pinout here
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I shined a light into the lens and measured the pads, but got no voltage at all. 12 looks like either + or ground, then it looks like it was driving 2 diodes at a time per lead
 

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Bionic-Badger

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I wouldn't put bare diodes in parallel with the current source. If one of those diodes gives up the ghost, the other diodes are going to receive the excess current which will create more stress on the other diodes. Then those diodes start to fail, repeating the process in a chain reaction until all your diodes are dead like a cheap Christmas light string.

Either put them in series, or regulate each diode separately with a driver or resistor or something of that nature.
 
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AMooMooCow

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I wouldn't put bare diodes in parallel with the current source. If one of those diodes gives up the ghost, the other diodes are going to receive the excess current which will create more stress on the other diodes. Then those diodes start to fail, repeating the process in a chain reaction until all your diodes are dead like a cheap Christmas light string.

Either put them in series, or regulate each diode separately with a driver or resistor or something of that nature.

Good point. That's why nobody drives diodes in parallel. I need to go home and rethink my circuit
 

RedCowboy

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I haven't read the tread yet, I just glimpsed it.
However when I drive a block of diodes way past factory spec, somewhere just south of fold back, I will not rely on perfectly matched internal resistance to drive in series or parallel, I will use a driver for each diode, at least until diodes become cheaper than drivers.
 

Cyparagon

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You can add a balance resistor to each string. 1ohm 2W would be plenty to ensure even current sharing. Laser diodes almost never fail short or open, so a cascading failure isn't an issue, really. I've driven these blocks from a single 0-30V 0-10A bench supply. ~6A at ~27V.
 
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