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+12VDC to -12VDC conversion

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  • +12VDC to -12VDC conversion

    I have a little power supply that's looking good to use with my SBC, but it only outputs +5VDC and +12VDC. Now, I'm not entirely sure that this motherboard can't be run off just the +5 and +12 (or even just the +5, for that matter), but assuming it can't, is there any easy way to get -12VDC out of either +5 or +12?

    Thanks,
    Matt

  • #2
    Originally posted by r0cket-:
    <STRONG>I have a little power supply that's looking good to use with my SBC, but it only outputs +5VDC and +12VDC. Now, I'm not entirely sure that this motherboard can't be run off just the +5 and +12 (or even just the +5, for that matter), but assuming it can't, is there any easy way to get -12VDC out of either +5 or +12?

    Thanks,
    Matt</STRONG>

    Check out Aaron Cakes website and look up the voltage inverter circuit. www.aaroncake.net The one based on the 555 works just fine, He numberd the pins wrong in the drawing (7 and 8 are swapped), but it is the same as astable operation as discribed in the data sheet.

    you can get enough voltage out of it to power mobos that need the -12 for the serial port to work.
    Almost nothing these days runs off of the - 5 though.

    Jeff_
    MPEGBOX - Plexiglass Computer
    www.mpegbox.com

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    • #3
      What SBC do you have by the way?

      Jeff_
      MPEGBOX - Plexiglass Computer
      www.mpegbox.com

      Comment


      • #4
        Originally posted by Jeff Mucha:
        <STRONG>
        Check out Aaron Cakes website and look up the voltage inverter circuit. www.aaroncake.net The one based on the 555 works just fine, He numberd the pins wrong in the drawing (7 and 8 are swapped), but it is the same as astable operation as discribed in the data sheet.
        Jeff_</STRONG>
        Oh god, this damn thing again. That drawing has haunted me ever since I put it up. The original schematic was wrong, so I corrected it. My correction was wrong, so I corrected. Soon I started recieving tonnes of contradicting email about my correctins, pin numbers, etc. So finally, I just gave up. . Since I no longer maintain the electronics sections of my site, I no longer care. Sigh.

        So, my word of caution with that schematic is that is may work, it may not, but it will NOT produce -12V. It will produce closer to -10.5V, which may be enough, it may not.
        Player: Pentium 166MMX, Amptron 598LMR MB w/onboard Sound, Video, LAN, 10.2 Gig Fujitsu Laptop HD, Arise 865 DC-DC Converter, Lexan Case, Custom Software w/Voice Interface, MS Access Based Playlists
        Car: 1986 Mazda RX-7 Turbo (highly modded), 1978 RX-7 Beater (Dead, parting out), 2001 Honda Insight
        "If one more body-kitted, cut-spring-lowered, farty-exhausted Civic revs on me at an intersection, I swear I'm going to get out of my car and cram their ridiculous double-decker aluminium wing firmly up their rump."

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        • #5
          Well I can vouch that other than the pins 7 and 8 connections, it is RIGHT.

          Jeff_
          MPEGBOX - Plexiglass Computer
          www.mpegbox.com

          Comment


          • #6
            I have an Advantech PCA-6154. I asked Advantech about it and they just told me to buy one of their power supplies, but **** that (I haven't checked, but I'm sure they want a good $50 or $60 for one). I may just try it without the -12 line.

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            • #7
              r0cket-: Where did you happen to buy your power supply? I'm in the middle of installing mine in my car and all I need is the power supply. Is there a web site for the Advantech PCA-6154?

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