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5.5V 2.2W Power Supply???

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  • 5.5V 2.2W Power Supply???

    I have an odd power requirement. I need a 5.5V 2.2A power supply. I've already built a 5v 6A power supply (using a PT6625) and now I guess I need another one.

    The PT6625 will need to remain at the same output (it is driving 2 powered hubs).

    Someone please help. I would assume I can use an LM1084 with some resistors and caps. Please be specific if making a suggestion, I'm not an electrician or an engineer - thanks!

    -HD

  • #2
    Originally posted by joshthepilot
    You can hit up radio shack for their variable voltage regulator. It can do up to 1.5 amps which meets your 2.5Watt specs. It uses 2 resistors to set the voltage. Bring a calc with you because I think it says on the back the simple formula. Then you can buy the resistors at the same time.
    Thanks for the answer...

    Oh Crap - I meant 2.2 Amps...I'm assuming if my device pulled that many amps of this regulator, it would burn out regardless of the size of the heatsink...?

    -HD

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    • #3
      whats wrong with using the same ic (PT6625) for the 5.5 volt's output..?

      edit:

      i mean, you should be able to use the same regulator (1 for each design )
      just put some resistors to vo(adj) pin 14
      heres is a datasheet
      http://grok.ecn.uiowa.edu/Internal/V...tor_pt6620.pdf

      2 edit:
      28,4k between pin 14 and Ground (pin 7-10)
      Sorry for the english

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      • #4
        Josh - thanks for the suggestion. Just to let you know, I'm running (2) 5V 2A usb hubs off the PT6625. I've attached a drawing of what my circuit currently looks like.

        If you have time, please modify it and let me know what I need to do to get me 5.5V on one line while keeping 5V on the other 2 lines. Thanks!
        Attached Files

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        • #5
          hd

          you can add a 28.4k ohm resistor between the V adj and the ground.

          it will give you a 5.5 v out.

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          • #6
            Originally posted by xtra
            hd

            you can add a 28.4k ohm resistor between the V adj and the ground.

            it will give you a 5.5 v out.
            Thought this would be pretty simple, so I went to Digikey.com and couldn't find any resistor with a value of 28.4k.

            Do these exist???? Thanks!

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            • #7
              you can put resistors in series and parallel to get different values. if you put them in series the values add up... so a 27k and 1.4k in series gives you 28.4k
              But don't take it from me! here's a quote from a real, live newbie:
              Originally posted by Viscouse
              I am learning buttloads just by searching on this forum. I've learned 2 big things so far: 1-it's been done before, and 2-if it hasn't, there is a way to do it.
              eegeek.net

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              • #8
                Resurrecting this thread from the dead. Anyone know if the PT6625 can output 10v? If so where do I hook up the resistor? Thanks.

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                • #9
                  NM, started new thread...

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