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dual power supply design

Discussion in 'Electronic Basics' started by panfilero, Mar 12, 2009.

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  1. panfilero

    panfilero Guest

    Hello,

    does anyone know if there's any way to design a simple low power dual
    power supply? The result should be able to swing between -2V and 2V
    (for example, the values are not important just giving an idea of the
    range) and supply around.... 200mA (again just an idea... around here
    somewhere).

    The output of the power supply should (ideally) consist of two wires
    that I can swing between +/- 2V. I'm open to any type of control...
    I'm guessing it will end up being a pot, although voltage control or
    current control would be nice... however, that is not really what I'm
    trying to figure out right now.

    I'm just wondering if someone can point me in the right direction
    here... I'm having a hard time trying to figure out where to begin
    with this design.

    much thanks!
     
  2. Guest

    As always, you need to state what you are starting with, and your
    specific goal. Yes, most things are possible, but the means to the
    end depends on the specifics.
     
  3. Kirk Johnson

    Kirk Johnson Guest

    Maybe give this a try lad

    http://www.imagefap.com/image.php?id=1988478267

    Always works wonders for me!

    Kirk Johnson
    "Stretching Specialist"
     
  4. neon

    neon

    1,325
    0
    Oct 21, 2006
    use a simple lm317 just bias it off to -5v. YOU CLOULD expand and add a pwm but that is not simple.
     
  5. stan

    stan Guest

    Rough and ready; unsophisticated!
    1) Find a design for a power supply of around four to five volts. With
    a centre tap.
    2) And there are other circuits that can be arranged from a
    transformer without a centre tap that can also provide plus and minus
    supplies from the same winding. With a 'virtual' centre tap or zero
    voltage point.
    3) A pot placed across the two outputs can be adjusted to anywhere
    from plus 2 to to minus 2 volts; relative to the centre tap of item
    (1) or the created zero of item (2).
    4) For two separate outputs use two separate pots arranged thus.
    As a guess you prob. need power supplies providing an amp or more and
    then 'sink' some of it in the pots.
    Depending on whether the 200 m/a is a steady or varying load?
    All depends what you are trying design/do!
     
  6. Ross Herbert

    Ross Herbert Guest

    :Hello,
    :
    :does anyone know if there's any way to design a simple low power dual
    :power supply? The result should be able to swing between -2V and 2V
    :(for example, the values are not important just giving an idea of the
    :range) and supply around.... 200mA (again just an idea... around here
    :somewhere).
    :
    :The output of the power supply should (ideally) consist of two wires
    :that I can swing between +/- 2V. I'm open to any type of control...
    :I'm guessing it will end up being a pot, although voltage control or
    :current control would be nice... however, that is not really what I'm
    :trying to figure out right now.
    :
    :I'm just wondering if someone can point me in the right direction
    :here... I'm having a hard time trying to figure out where to begin
    :with this design.
    :
    :much thanks!


    I don't know exactly what you hope to achieve by being able to "swing between
    -ve and +ve" using "two wires".

    One of the output wires has to be the nominal reference or common wire which
    means that the other wire must be able to ramp up to some +ve value when
    rotating a potentometer in one direction. Alternatively, this wire will also be
    able to ramp down to some -ve value by rotating the pot in the other direction.

    Is this what you mean?

    Usually, a power supply is used for a specific purpose and if it is required to
    be voltage adjustable, then its output range is between the value of 0V to some
    +ve maximum, OR from 0V to some -ve maximum on another wire which is referenced
    to the 0V wire, ie. the output wire can go no lower than 0V referenced to the 0V
    or common wire.
     
  7. How much of a consideration is efficiency, and what power does it need
    to run on? Does it produce +2V and -2V at the same time, or do you
    need to swing it end to end?

    If it's AC, I'd use a transformer to reduce line power to about 10V
    peak to peak, center tapped, to ground, rectify it on both sides to get
    +5V and -5V, filter to get the ripple down to under a volt and then use
    a power op-amp with variable gain off a voltage reference to get the
    output voltage.
     
  8. Guest

    ? ISN'T THAT A SONG ?

    I AM PROTEUS
     
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