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unknown LED Driver IC

Discussion in 'General Electronics Discussion' started by davenn, Jun 29, 2011.

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  1. davenn

    davenn Moderator

    13,880
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    Sep 5, 2009
    hi gang

    got all these LED chasers. The flamin' manufacturer's scrapped the IC # off the chip :rolleyes:

    its a 4pin DIL (ie. the same as a 555 timer) google searches turned up lots of PIC driven LED chasers. Wonder if this is a PIC or some other linear IC anyone come across a cct like this ?

    [​IMG]

    Cheers
    Dave
     

    Attached Files:

  2. hexreader

    hexreader

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    Apr 21, 2011
    I would be fairly confident that this is a PIC microcontroller.

    Probably PIC12F629.

    Possibly PIC12F675.

    Possibly PIC12F683.

    Be aware that a replacement PIC would need to be programmed before it will do anything.

    Hope this helps
     
    Last edited: Jun 29, 2011
  3. davenn

    davenn Moderator

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    Sep 5, 2009
    hey mate

    yeah the 12F629 seems a reasonable candidate even has the correct pins for power supply ;)

    I mite unsolder one out of cct and see if I can read the firmware. That if they havent set the code to stop the reading of the chip. worth a crack at it

    thanks
    Dave
     
  4. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Unlikely to be a PIC given the way the inductor is connected. (that's assuming the inductor is used to boost the incoming voltage)
     
  5. davenn

    davenn Moderator

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    Sep 5, 2009
    ok any thoughts on what else it mite be ?
    I dont know of any specific LED driver chips googling such just provided lots of links to PIC drivers

    Dave
     
  6. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Looking at that circuit again, I can't see that it could be a boost regulator. Maybe the inductor forms part of a filtering circuit. If it does, then I guess it could be a PIC.

    But it seems unusual to have an inductor there... And the resistor across the incoming power supply... Weird.
     
  7. davenn

    davenn Moderator

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    Sep 5, 2009

    yeah why the hell would you hang a 560 Ohm across the supply ??

    who knows


    D
     
  8. duke37

    duke37

    5,364
    772
    Jan 9, 2011
    Is that a Zener diode or just an ordinary diode acting as a freewheel?
    It looks suspiciously like a voltage convertor to me, earthing the inductance to get sufficient current and then dumping it into the leds, Cunning.
     
  9. MagicMatt

    MagicMatt

    70
    0
    Jun 15, 2011
    I'm sure that's a PIC, as they have the MCLR pin pulled up. Each pin can usually drive 20-25mA which is enough to drive a single LED.

    The program on the PIC is likely to be VERY simplistic, just cycling turning one bit on a register, but you'd need a cheap programmer.

    I can't recall exactly where I've seen that config before, but it was to do with driving LEDs from a coin cell, so I agree it's probably a booster of some sort.
     
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