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Thread: Needing help with a driver...

  1. #1
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    Question Needing help with a driver...

    I have a diode of unknown iop and voltage drop{1.8?}......I would like a bit of help with a LM-317 based simple driver setup that I can again use this one. I have a lot of parts here and could possibly escape another order. The outputs from the AC powered driver, when it was functional, was 2.97vdc @ 268maH of current. It would be nice to power it from 6 vdc. Lucky for me I wrote these things down a couple of years ago. Yes years. I really would like to make it myself. I know Die4drive is great. Any help would be better than selling the pieces off.....I would rather finish it to working shape again.
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  2. #2
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    Cool

    I've had really good luck with "Sam's Laser Diode Test Supply", which is based on a pair of LM-317's. (One is used for the voltage regulation stage, the other for current limiting.) Unfortunately, there is no support for blanking.

    I always wanted to see if a mosfet stuck between the voltage regulation stage and the current regulation stage would allow the driver to blank quick enough for laser show use, but I never got around to experimenting with the idea. (Lots of capacitance in both circuits, so it might not work...)

    Adam

  3. #3
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    Default

    That looks good.....I wonder if the 317 can bleed off the heat from a 14.2 volt input with sinks. I am using lithium cells for the power supply. This is for the 200mw 532nm man sized portable project. Hope to bring it to SELEM 2 if it is finished by then.....I will set up a test circuit and see what it takes to get the 300mah of drive current. This is threshold.....it normally ran with 680maH @197mw output.
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    Cool

    Quote Originally Posted by MechEng3 View Post
    That looks good.....I wonder if the 317 can bleed off the heat from a 14.2 volt input. I am using lithium cells for the power supply. This is for the 200mw 532nm man sized portable project. Hope to bring it to SELEM 2 if it is finished by then.....
    Shouldn't be a problem so long as you heat sink it properly. They're rated for a 50 volt drop at 2 amps. But they will get hot, so make sure you mount them to a decent heat sink.

    I've used them with up to a 10 volt drop at around 150 ma with no heat sink, but I wouldn't push them any more than that unless you add a heat sink. (They got pretty hot that way without the heat sink)

    Adam
    Last edited by buffo; 01-15-2008 at 14:34.

  5. #5
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    Default You could try this one

    This is a constant current set-up using one LM317 If your fixed res is 3ohms I think it should do the job. Ignore the pin numbers on the regulator, wire it up to the pin descriptions.

    Regards rog8811
    Attached Thumbnails Attached Thumbnails LD_Driver_Schematic.jpg  


  6. #6
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    Default

    Quote Originally Posted by rog8811 View Post
    This is a constant current set-up using one LM317 If your fixed res is 3ohms I think it should do the job. Ignore the pin numbers on the regulator, wire it up to the pin descriptions.

    Regards rog8811
    That ones fine if you do 2 things, use at least a half watt rated pot, and two dont tweek the pot with the actual diode attached, if the wiper lifts it goes bang if the load is a LD. I use a luxeon led with a silicon diode in series as a test/cal load.

    Steve

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