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dual power supply

Discussion in 'Power Electronics' started by rody311, Mar 3, 2010.

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  1. rody311


    Feb 19, 2010
    hey guys,

    I am building a project which needs to power a galvo amplifier, the amplifier needs a +-28V. I am trying to find a dc power supply that can provide me with a positive and a negative 28v supply rails but the maximum i've been able to find are ones that either give only positive voltages or the ones that do actually give both the positive and the negative rails only go upto 5V. And I've come across a lot of simple circuits that will probably allow me to do that but my supervisor needs for it to be an off the shelf product so it'd be great if someone could point me in the right direction. here's a link to a picture of what I've already got but this has a common negative terminal between the two outputs so i can't derive a negative rail off it.

  2. saurabh17g


    Mar 8, 2010
  3. rody311


    Feb 19, 2010
    Thanks for that saurabh but I think the voltage regulator would've worked perfectly if I already had a DC voltage that was high enough to be downstepped to 28V and even if I did have a DC supply that was high enough, designing a split power supply that uses 2 of these voltage regulators wouldnt've been of any use anyway since the two would've driven their voltage off the same source which effectively would've made their negatives common and connecting them in series would've shorted out the two supplies. What I was looking for was something that'd either give me a negative and a positive rail or a power supply that had two outputs that were isolated from each other so I could connect them in series. But what I ended up going with in the end is two separate power supplies connected in series together, even though the two take up a good amount of real estate and start to resonate when connected in series together because of the switching elements inside, I've found that routing the outputs of the two supplies through a ferrite core actually gets rid of all of the high frequency krap that otherwise would've fed back into the circuit and caused the two to blow up.

    but i appreciate your help.
    Last edited: Mar 9, 2010
  4. 55pilot


    Feb 23, 2010
    Glad to see that you know enough to call BS on bogus advice, even if you do it far too diplomatically for my taste :)

    Not knowing too much about galvo amplifiers, I have a few questions. How much current do you need at +/-28V? How much continuous current and how much peak current?

    Why do you want to built it yourself rather than buying one new or used?

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