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12V 4.16amps

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  • 12V 4.16amps

    Hello,

    I would like to put a KDS Rad-5 lcd in my car. The problem is powering the thing. It takes 12v at 4.16amps. Does anyone have any idea where to get or how to build a regulator that will make this work??

    Thanks guys
    This post college life is a real drag

  • #2
    I can sell you one for 60 dollars..
    MPEGBOX - Plexiglass Computer
    www.mpegbox.com

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    • #3
      If you're appropriately saavy you can use a low-dropout linear regulator (LM1084) on a decent heatsink to do that.

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      • #4
        Originally posted by RobM
        If you're appropriately saavy you can use a low-dropout linear regulator (LM1084) on a decent heatsink to do that.
        If that will work for you.

        I have a 12 volt 5 amp design that takes in 9 to 18 volts and puts out 12.
        MPEGBOX - Plexiglass Computer
        www.mpegbox.com

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        • #5
          Originally posted by zootjeff
          If that will work for you.

          I have a 12 volt 5 amp design that takes in 9 to 18 volts and puts out 12.
          I didn't mean to respond to your post; obviously a switcher is a better idea but a LDO linear is a cheap 90% solution. A lot of this stuff have their own power supplies built in anyway.

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          • #6
            Here:

            12V/5A

            http://www.geocities.com/andrewmuck/PSU.htm
            Diego Soares

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            • #7
              Look at Digikey for overpriced but obscure electronic components.

              www.Digikey.com

              Catalog, page 443. Its a TI switching regulator IC for 12V @ 5A with an input voltage of 3 to 28 volts. (Yeah, I'm skeptical too.)

              Part Number PT6656[D/E/P] (D/E/P will depend on SM, horizontal, or vertical mount package.)

              This is almost 30 dollars.

              Then you need special capacitors of 550uF and 330uF that are made by Panasonic, also available at Digikey.

              The papers for this IC is available at Texas Instrument's web site.
              Free entrance to heaven? WOW! I DUN BELIEVE! JC!

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              • #8
                With regards to the question. 12v 4.16Amp. Did you find a suitable regulator?

                I am on the search for a 12v 4.58Amp regulator for the EPIA M 9000 board. I have seen these DC to DC 12v 5AMP regulators but it seems to me that if the manufacturer placed there spec @ 12v 4.58Amp or in your case 4.16Amp, they did it for a reason.

                Can anyone help on this. I have the kit but am nervous of putting it into the car without a regulator.
                Lilliput 8", C134 EPIA-M 900 (Black), A1-ITX, 256 Mb RAM, 40 Gb HDD, DVD, 802.11g, mini keyboard

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                • #9
                  Not trying to hi jack the thread here but....

                  Since it's been suggested that you use the PT6656 I figured I'd drop this in. Perhaps you'll benefit from it. You can get the PT6656 from Texas Instruments from free and best of all you can have it tomorrow. If you go to www.ti.com and register for samples they will overnight it to you. That being said you will need two capacitors (560uF and 330uF) and some time to get everything going.

                  Now here's where my question comes in. I am trying to regulate 12 volts with this setup and it doesn't seem to be working right. I have a PT6656 and 570uF of capacitance on the input and 320uF on the output. I couldn't land 560uF and 330uF capacitors but from my days of electronics school I seem to remember that capacitors in parallel add together and that there is generally a 20% tolerance where a circuit should still perform correctly.

                  On the input I have one 470uF and one 100uF in parallel and on the output I have one 220uF and one 100uF in parallel. All cap's are 35v. I've triple checked all of my connections and everything and can't seem to find the problem. What the circuit is doing is mimicking a linear regulator. Any voltage above 12 get's brought down to 12v but anything below get's passed to Vo. I've tried tieing Vadj to Vo and Gnd. This adjusts the output to the high and low end but doesn't correct the problem. I've also tried tieing remote to the output this also fails to correct the problem. All of my test were performed with a small load on the circuit. Any ideas?

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                  • #10
                    Either digi-key or someone else has the wrong specs, from TI's site the PT6656 is a step down onyl regulator. For step up and step down you would need something like the PT5071 (its only 1.5A though)

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                    • #11
                      Ummm. It's an ISR. Integrated Switching Regulator.

                      http://www-s.ti.com/sc/ds/pt6656.pdf


                      Doesn't "switching regulator" mean it will step up or down as needed?

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                      • #12
                        Nope, read the spec sheet again. In particular, may I refer you to the specs on the Input Voltage Range where it says that the minimum is Vo+3. Ie, you need 3V of headroom on the regulator.


                        Rob
                        Old Systems retired due to new car
                        New system at design/prototype stage on BeagleBoard.

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                        • #13
                          Response is on

                          http://www.mp3car.com/vbulletin/show...8886#post98886

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                          • #14
                            Originally posted by Pred8tr
                            Ummm. It's an ISR. Integrated Switching Regulator.

                            http://www-s.ti.com/sc/ds/pt6656.pdf


                            Doesn't "switching regulator" mean it will step up or down as needed?
                            Nope

                            A switching regualtor can be just step down, or just step up, or both. The 6656 is a step down, a PT4051 for example is a atep up. Switching basically means just that switching. It has some sort of oscolator that pulses a switching transsitor to switch the input on and off fasy at the percentage needed to create the output. For step up they pulse the input through a coil to get a higher output. Look at the whole family chart http://focus.ti.com/docs/search/para...e&familyId=563 in the last colum at the description for step up/ step down/etc.

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