Efficient Power Supply

Discussion in 'General Electronics Chat' started by chrisw1990, Dec 15, 2011.

  1. chrisw1990

    Thread Starter Active Member

    Oct 22, 2011
    Hi All,
    my input voltage varies from around 12-20V, maybe dipping below 12V too sometimes.
    I require 12V 50mA power supply, an efficient one, my current schematic uses a step down, which then drives a step up (as well as other circuitry)
    how can i do this more efficiently?
  2. wmodavis

    Well-Known Member

    Oct 23, 2010
    A schematic would be helpful.
    ... "uses a step down, which then drives a step up"...

    A step down transformer then a step up transformer???

    That in itself is inefficient. If that is not what you mean you need to be more precise in your explanation. Or like I said a schematic would help. Can't read your mind though.
  3. Wendy


    Mar 24, 2008
    While it is technically possible to not use a transformer it is very unsafe to do so. For this reason a transformer must be used for a project done at AAC.

    Transformers generally are very efficient parts, their conversion efficiencies can exceed 95%, though it is not a given.

    A switching mode power supply (SMPS) is also very efficient, or can be. They tend to be a bit more noisy than their linear counterparts. The linear versions are much quieter, but make a lot more heat. Everything is a trade off.

    Submission: Power Supply Circuits

    I'm working on an article for the AAC book that is very much a work in progress. It may answer a few questions though.
  4. joeyd999

    AAC Fanatic!

    Jun 6, 2011
    You want a SEPIC converter. Google it.
  5. bountyhunter

    Well-Known Member

    Sep 7, 2009
    If the input is both above and below the regulated output, I beieve you need to use a buck-boost switcher.


    Last edited: Dec 15, 2011