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  • Small, cheap, 12V-12V regulator

    Possibly related to this post I just made

    What's the smallest/cheapest 12V-12V regulator out there? I don't want an ATX power supply, I just want something like the Carnetix P5V, but with twelve volts out instead of five.

    Can anyone advise?

    The Carnetix section of the mp3car store doesn't seem to contain anything appropriately small and cheap, nor the PSU section. I looked at mini-box website and all their really small PSUs appear to be ATX form factor - hardly convenient when what I really want is two wires, one that spits out electricities and one that takes them back in again.

    Thanks,
    Gary (-;
    OBDGPSLogger, for logging OBDII and/or GPS data
    OBDSim, an OBDII/ELM327 software simulator
    mp3car forums: obdgpslogger, obdsim

  • #2
    Of course, I write that and then I go find this bad boy:
    picoUPS 120 12V DC micro UPS

    What do you think? It's not available on the mp3car store, but it looks like even if I don't put a battery on it, it'll do what I want. For bonus points, I could put a battery on it and actually enjoy a UPS for my pogoplug...

    Gary (-;
    OBDGPSLogger, for logging OBDII and/or GPS data
    OBDSim, an OBDII/ELM327 software simulator
    mp3car forums: obdgpslogger, obdsim

    Comment


    • #3
      http://store.mp3car.com/Intelligent_..._p/pwr-034.htm
      this is a nice option too depending on your need

      Comment


      • #4
        How much current do you need? eBay has some switching regulators that do 1A for <$20.

        Comment


        • #5
          Punky: I actually have one of those at home, but for this particular project I'm shooting for something smaller.

          Nobb; nominally 8W, although startup will possibly be a bit more. [so... two thirds of an amp, but possibly more than 1A]

          Gary (-;
          OBDGPSLogger, for logging OBDII and/or GPS data
          OBDSim, an OBDII/ELM327 software simulator
          mp3car forums: obdgpslogger, obdsim

          Comment


          • #6
            you can do that using a single tiny regulator, there'll be a bit of heat thats all.

            Comment


            • #7
              How would that work?

              The truth, of course, is that now I'm thinking about putting in a UPS on purpose...

              Gary (-;
              OBDGPSLogger, for logging OBDII and/or GPS data
              OBDSim, an OBDII/ELM327 software simulator
              mp3car forums: obdgpslogger, obdsim

              Comment


              • #8
                I think Punky is forgetting the drop-out voltage as well as up conversion.

                FYI - a versatile kit for up to 50W, or 100W heatsinked (AUD$22.50 + P&P) - see Oatley Electronics Kit K168 - DC to DC Converter

                Comment


                • #9
                  I remembered looking this up at one point. I think this chip can do it:
                  http://www.national.com/ds/LM/LM138.pdf
                  However, for the cost, oldspark's suggestion will most likely be cheaper and easier.

                  Comment


                  • #10
                    The LM138 drops at least 1.5V across it, hence you need 13.5V in to get 12V out. (It's similar to the LM117/317, 780x & 790x 3-terminal regulators.)

                    In this application, being a UPS I assumed a typical 12V supply to supply 12V, hence say 11V - 15V in assuming a battery, or 8-16V in using typical automotive design specs.

                    If that regulation wasn't required, why not connect 12v to 12V?

                    Pity though - for 8W, cheap $2-$3 fixed 12V 7812 or adjustable 317k regs would do (up to 1.5A output).

                    Comment


                    • #11
                      You can cannibalize a cigarette power adapter for laptops. This particular model do 12V 3A (36W):

                      http://www.meritline.com/asus-eee-pc...x?source=s2010



                      It's really a switch mode DC-DC converter. It should take a range of voltage in, and output 12V. The exact range is not specified and I have not had the chance to do tests on it. May report my findings here once I test it.

                      Comment


                      • #12
                        It probably uses the TL494 (as used in the Oatley kit I linked above) or Motorola MC34063 etc etc SMPS chips.

                        Although they are fairly cheap (under AUD$5), the cheapest way is to buy cig-socket chargers & PSUs as per DanDan's reply, though mobile phone charges are usually cheaper.

                        Gone are the days of 3-terminal linear regulators.... Funny that SMPS is cheaper!

                        Comment


                        • #13
                          In the end, I ordered that UPS device from mini-box - the more I thought about it, the more enticing I found the idea of actually having a UPS that doesn't require the car battery to keep working. Finally my plugs will be able to shut down cleanly :-)

                          Gary (-;
                          OBDGPSLogger, for logging OBDII and/or GPS data
                          OBDSim, an OBDII/ELM327 software simulator
                          mp3car forums: obdgpslogger, obdsim

                          Comment


                          • #14
                            So what source are you using for the UPS function - a 2nd battery?

                            Comment


                            • #15
                              I'm going to pick up a small sealed lead acid battery; I explicitly don't need much power, and probably not for very long. We'll see.

                              Gary (-;
                              OBDGPSLogger, for logging OBDII and/or GPS data
                              OBDSim, an OBDII/ELM327 software simulator
                              mp3car forums: obdgpslogger, obdsim

                              Comment

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