CLASS D Amplifier Circuit Question

Discussion in 'The Projects Forum' started by Lucas Castelan Prado, May 12, 2016.

  1. Lucas Castelan Prado

    Thread Starter New Member

    May 12, 2016
    4
    0
    Hello everyone

    I`ve been searching about class D amplifies.

    What I know so far is that a class d amplifier is a switching amplifier.

    There are three steps in creating a classe d amplifier.

    1 - create PWM from signal.

    2 - amplify output from PWM with switching transistors

    3 - use a low pass filter.

    The problem is that in step two, I have 2 transistors from Vcc to ground.
    It seems that I need a delay circuit to prevent my circuit from having a short circuit from Vcc to ground(when both transistors would be conducting at the same time).
    But i can't find a circuit like that to help me
    Can anyone help me please?

    This is the block diagram
    https://upload.wikimedia.org/wikipedia/commons/4/4c/Pwm_amp.svg
     
  2. wayneh

    Expert

    Sep 9, 2010
    12,148
    3,058
    Do you want to build one or just get one? You can buy them very inexpensively - cheaper than you can make one.

    Have you searched for schematics for Class D amplifiers? You'll find hundreds. And yes, they all have to solve the "shoot through" problem.
     
  3. Lucas Castelan Prado

    Thread Starter New Member

    May 12, 2016
    4
    0
    i want to build one on ltspice
     
  4. #12

    Expert

    Nov 30, 2010
    16,330
    6,818
    A little correction, please. You can't "build" anything with a simulator program. The best you can do is simulate a circuit.
    Please don't say, "build" when you have no parts and no intention of connecting them together.
    Say, "simulate". This will avoid misunderstanding.
     
    absf and atferrari like this.
  5. ronv

    AAC Fanatic!

    Nov 12, 2008
    3,292
    1,255
    IR makes several with built in dead time. I have models for some of them.
    http://www.irf.com/product-info/datasheets/data/ir2184.pdf
     
  6. dannyf

    Well-Known Member

    Sep 13, 2015
    1,825
    364
    That's simply one of many ways to do a class D amp.

    Simply put, you can view a class D amp as a power comparator + a low-pass filter.
     
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