Help with this voltage conversion?

Discussion in 'General Electronics Chat' started by jean28, Jul 26, 2013.

  1. jean28

    Thread Starter Member

    Sep 5, 2012
    76
    0
    Hello, guys!

    I have a little issue. I'm using a micro and from a pin i get either 0V or 5V. I need to pass the voltage from that pin to something else that only works if it gets -2.5V or 2.5V. How can I convert the 0V to -2.5V and the 5V to 2.5V? I know that the 5 -> 2.5 can be done with a voltage divider, but how do I convert the 0 to -2.5 as well?

    Thanks!
     
  2. odinhg

    Active Member

    Jul 22, 2009
    65
    15
    Do you have a negative voltage supply available in your circuit?
    How much current do you need to source?
    How fast do you need to switch?
    What micro do you use?

    Answers to these questions would help others help you :)

    Edit:
    I'm still a beginner myself, but I did try to make a circuit that should do what you want. I'm not sure if it is a good solution, but it works in simulator. (Schematic attached)

    I did remove the resistor values, but they should be easy for you to figure out on your own. Take a look at the following articles if you're stuck:
    http://www.allaboutcircuits.com/vol_1/chpt_6/1.html
    http://www.allaboutcircuits.com/vol_3/chpt_8/9.html
     
    Last edited: Jul 26, 2013
  3. MrChips

    Moderator

    Oct 2, 2009
    12,418
    3,355
    Add -2.5V to your signal.
     
  4. WBahn

    Moderator

    Mar 31, 2012
    17,715
    4,788
    Depending on exactly what you have and what you are doing, you may be able to just refer the second part to half the micro's supply voltage and be done.
     
  5. Ron H

    AAC Fanatic!

    Apr 14, 2005
    7,050
    656
    Excellent point.
    Jean12, tell us the big picture of what you are trying to do.
     
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