Audio Amplifier Design (CE Amplifier - Class AB Power Amplifier)

Discussion in 'The Projects Forum' started by Deepak Reddy Kovvuri, Apr 25, 2016.

  1. Deepak Reddy Kovvuri

    Thread Starter New Member

    Apr 25, 2016
    1
    0
    I am trying to design a Audio Amplifier which provides a gain of 20db (10V/V). I have managed to design the following circuit but the output voltage gets clipped and clamped. Please find the schematic file at http://www.sendspace.com/file/i5rw9n

    [​IMG]

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  2. arunpradh

    Member

    Dec 11, 2013
    42
    3
    in the coupling stages you dont need 470uF insted of lesser values such as 4u7 or 2u2. check the dc bias of driver side. for how much power the amp is designed for?
     
  3. #12

    Expert

    Nov 30, 2010
    16,337
    6,821
    The 2N3906 is wrong way up.
    You can't send a whole amp through these tiny transistors.
    There is too much current in R2 compared to R3. You are running out of voltage at R3.
     
    arunpradh likes this.
  4. Ramussons

    Active Member

    May 3, 2013
    557
    92
    Feedback is a vital element in amplifiers.
    The overall gain of an amp is (to be) decided by the feedback elements.
     
  5. #12

    Expert

    Nov 30, 2010
    16,337
    6,821
    The Thread starter did not ask for a power amplifier, he asked how to fix his design.
     
  6. Marley

    Member

    Apr 4, 2016
    144
    40
    As has been said, you need feedback from the output back to the input stage to set the overall gain of the amplifier.
    Carefully designed, this feedback also sets the DC operating point and reduces distortion.

    For a simple design with descriptions of the operation, have a look at this.
     
  7. AnalogKid

    Distinguished Member

    Aug 1, 2013
    4,545
    1,251
    Since your intent is limited forward gain with no overall negative feedback, delete C5. It is the cause of the clipping. At audio frequencies, Q2 is trying to provide infinite gain.

    If the output transistors heat up with no signal, change D1 and D2 to 1N914 / 1N4148. The lower forward voltage drop will decrease the static current through the output stage.

    ak
     
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