TPR1 - to drive LED floods?

Discussion in 'Strobes - LED or Others' started by LabRat, Jul 15, 2010.

  1. LabRat

    LabRat New Elf

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    Just throwing out this idea for discussion. (oh.. and Hello.. I'm Andrew... and I like blinky flashy)

    Take the basic TPR1 (no PIC) which is essentially a constant current driver, that can handle up to 12v.
    If using something akin to the Mighty Mini (re-jigged to be 3 LEDs in a row (12v instead of 24)), couldn't
    the TPR1 be used to drive these? (One per colour) Instead of using current limiting resistors?

    Or is heating (and heat dissipation) an issue ... so it will work for strobing, but not for lighting?
     
  2. Tabor

    Tabor Full Time Elf

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    Yes, it could.

    The basis to the strobe board is the NUD4001 chip, to set it up as a constant current driver requires only one resistor.
    you can then drive up to 500mA.
    It will even work up to 24vdc.
    Heat could become an issue, the data sheet explain heat dissipation calculations for the chip.
    Our tests with the NUD4001 have shown it to be quite resilient.
     
  3. budude

    budude Way behind schedule - again...

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    The problem with that is the number of devices you will need. Even for the standard MM you would require eight CC drivers. You have to drive each path separately because if you go by each color you would not get even distribution of the 200mA of current. One side will get more current and may eventually blow. This would then shoot all the current down the other leg and blow them out. If you hack them down to 12v, you will now have 16 paths of 100mA and would need 16 CC drivers...

    I'm working on using LM317 regulators as CC sources but the 24v source is causing heat issues...
     
  4. DanoNJ

    DanoNJ Full Time Elf

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    How about for the Rainbow floods??
     
  5. chilloutdocdoc

    chilloutdocdoc Full Time Elf

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    Rainbow floods have even more rows, at 18 total, 6 parallel's per color. Constant current, to be designed at a low cost (relative) is meant to have one parallel of LED's, all at a set current. An example of this would be a high power "star" LED (1-5W) There are some chips out there that have more than one regulated output, but they are more expensive.
     
  6. budude

    budude Way behind schedule - again...

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    Yep - exactly right - RJ at DLA has the right idea (as usual) with the Aether with fewer but higher power LEDs. Multiple parallel paths mean multiple CC drivers. But of course the better LEDs come with a higher cost so it's good to look at alternatives which still get the job done at a lower cost as well.
     
  7. AussiePhil

    AussiePhil Dedicated Elf Administrator

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    Andrew

    I think everyone summed it up well, CC is the correct thing to do but the NUD is not the cheapest solution for what you want, and most will be hard to retrofit.

    Cheers
    Phil
     

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