+ Post New Thread
Page 2 of 2 FirstFirst 1 2
Results 21 to 27 of 27
  1. #21
    Member level 1
    Points: 522, Level: 4

    Join Date
    Oct 2017
    Posts
    33
    Helped
    0 / 0
    Points
    522
    Level
    4

    Re: Lets take a look on a linear amplifier

    Quote Originally Posted by KlausST View Post
    Hi,

    I did low frequency (30..70Hz) sinwave via classD, then filtering, then transformer to get about 200V RMS as measurement signal.
    It worked great, about no heating, high efficiency, good signal quality.

    Klaus
    Nice !
    Interesting to see how was your input? Its analog or PWM ?
    My measurement range is 300V RMS.

    Kindly suggest a same range classD ic.
    Hasan



    •   AltAdvertisement

        
       

  2. #22
    Advanced Member level 5
    Points: 53,716, Level: 56
    Achievements:
    7 years registered
    Audioguru's Avatar
    Join Date
    Jan 2008
    Location
    Toronto area of Canada
    Posts
    8,749
    Helped
    2053 / 2053
    Points
    53,716
    Level
    56

    Re: Lets take a look on a linear amplifier

    Most class-D audio amplifiers have an analog input. Some have a digital input. They convert the input signal to PWM inside the amplifier.



  3. #23
    Member level 1
    Points: 522, Level: 4

    Join Date
    Oct 2017
    Posts
    33
    Helped
    0 / 0
    Points
    522
    Level
    4

    Re: Lets take a look on a linear amplifier

    Quote Originally Posted by Audioguru View Post
    Most class-D audio amplifiers have an analog input. Some have a digital input. They convert the input signal to PWM inside the amplifier.
    Did you see "electrotech" posted datasheet well?
    what is the limit of such analog/PWM input frequency?
    Not high compared than my one??
    Hasan



    •   AltAdvertisement

        
       

  4. #24
    Advanced Member level 5
    Points: 53,716, Level: 56
    Achievements:
    7 years registered
    Audioguru's Avatar
    Join Date
    Jan 2008
    Location
    Toronto area of Canada
    Posts
    8,749
    Helped
    2053 / 2053
    Points
    53,716
    Level
    56

    Re: Lets take a look on a linear amplifier

    The Texas Instruments TPA3220 class-D amplifier IC datasheet shows an output bandwidth of 100kHz and an internal class-D switching frequency of 480kHz. The circuit shows output filters to remove the 480kHz.

    You said:
    "Did you see "electrotech" posted datasheet well?
    What is the limit of such analog/PWM input frequency?
    Not high compared than my one??"
    But I cannot understand what you are asking about. (Poor English?)



  5. #25
    Member level 1
    Points: 522, Level: 4

    Join Date
    Oct 2017
    Posts
    33
    Helped
    0 / 0
    Points
    522
    Level
    4

    Re: Lets take a look on a linear amplifier

    The Texas Instruments TPA3220 class-D amplifier IC datasheet shows an output bandwidth of 100kHz and an internal class-D switching frequency of 480kHz. The circuit shows output filters to remove the 480kHz.
    Then my application wont work with it?
    Take a look....
    Click image for larger version. 

Name:	audio_bandwidth.PNG 
Views:	6 
Size:	4.6 KB 
ID:	155725

    Dont mind Guru, you seems like an indian by name and Chiness by birth!
    Last edited by Hasan2017; 27th September 2019 at 04:47.
    Hasan



    •   AltAdvertisement

        
       

  6. #26
    Super Moderator
    Points: 260,253, Level: 100
    Awards:
    1st Helpful Member

    Join Date
    Jan 2008
    Location
    Bochum, Germany
    Posts
    45,450
    Helped
    13829 / 13829
    Points
    260,253
    Level
    100

    Re: Lets take a look on a linear amplifier

    Class D should have absolutely no problem to realize the sketched frequency response. You never revealed bandwidth requirements along this thread b.t.w.



  7. #27
    Advanced Member level 5
    Points: 53,716, Level: 56
    Achievements:
    7 years registered
    Audioguru's Avatar
    Join Date
    Jan 2008
    Location
    Toronto area of Canada
    Posts
    8,749
    Helped
    2053 / 2053
    Points
    53,716
    Level
    56

    Re: Lets take a look on a linear amplifier

    I was called "Audioguru" by a salesman at an audio engineering company I worked for, because a Guru is an expert and master. The salesman and I are not Indian.
    I was born a white Canadian and have always been a white Canadian. I have never been to India or China and never want to go there.

    All good audio amplifiers produce frequencies from 20Hz to 20kHz and most reach 100KHz. Your graph shows a -3dB response from about 3Hz (too low for audio) to about 20kHz. Then your amplifier will not produce the top audio octave of frequencies from 10kHz to 20kHz accurately since -3dB is half the power.

    On one of the many other forums you are on talking about this project you said the bandwidth you need is from 45Hz to 65Hz. It seems that you are trying to copy a calibration instrument for instruments that measures 3-phase electrical power factor.


    1 members found this post helpful.

--[[ ]]--