level shifter +5 in negative out

Discussion in 'The Projects Forum' started by aad, Sep 22, 2009.

  1. aad

    Thread Starter New Member

    Sep 22, 2009
    3
    0
    Looking for a transistor based voltage level shifter:
    Input 0 - 5 V (logic from microcontroler)
    Output -28 V (to drive a VFD display)
    Using 1 or 2 transistors/fets
     
  2. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    OK, so you have logic levels of 0v or 5v for an input.

    But you've only specified -28v for the output. Is it supposed to always stay at -28v, or switch between -28v and 0v, or some other voltage?
    [eta]
    If you want to go from 0v to -28v, see the attached for one way to do it.
     
    Last edited: Sep 22, 2009
  3. aad

    Thread Starter New Member

    Sep 22, 2009
    3
    0
    Actually the switched voltage is +5 and -28V.
    at +5V the current to the VFD is between 1 to 12 mA
    at -28 the current to the VFD is 0 mA

    may it is possible to do this with just 1 transistor?
     
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