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question regarding DC/DC supply

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  • question regarding DC/DC supply

    Okay guys, I am working on the DC/DC supply for my carputer and had a few questions and wanted a few opinions regarding what i'm using.

    Just for a little background, my system does not need negative voltages for anything (my sbc generates them onboard i think).

    For 5V, I am using an Astec power module that accepts 9-36V DC and adapts it down to 5V at up to (a theoretical) 3A.

    see below link for a pic of the module.

    12V is where things may get a little tricky for me. I dont need all that much to run the hard drives or mainboard, but my 10" VGA LCD runs off 12V @ 2A and I would like to run it off of the same supply unit (if possible). My question is, are there any regulators (cheap *** linears only do 1A if i recall) beefy enough to give me the 2-3A I need?

    I also am thinking that I would need some sort of crowbar or tank circuit (I've seen some that use a 50mH inductor and a 2200uF capacitor) to protect from startup voltages and to smooth out the input. What are your thoughts on this?

    Thanks for any help that can be provided.


  • #2
    There are several 12V linear regulators rated from 1-5A. Search the National Semiconductor site and you should find them. You will need to use a "low dropout" variety. You shouldn't need any filtering, except for a few capacitors at the input and output of the regulator.
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    • #3
      If you need the current, have a look at the LM2576 voltage "regulators" they'll put out 3amps. I know someone who's used them before and had no problems, and 4 external component's makes them pretty simple.

      Hope that helps.

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      • #4
        Hey buddy .. i know the exact regulator you can use .. its called LM1084 from national it come in 5, 12, 3.3 its rated 5amps

        Very cool chip !:-) got 10 of them



        • #5
          Originally posted by mastero:
          <STRONG>Hey buddy .. i know the exact regulator you can use .. its called LM1084 from national it come in 5, 12, 3.3 its rated 5amps

          Very cool chip !:-) got 10 of them

          They don't work, for some reason, not happy with a 14volt input, the 12volt ones that is, they won't regulate right..