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Lets take a look on a linear amplifier

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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.
 

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

Did you see "electrotech" posted datasheet well?
what is the limit of such analog/PWM input frequency?
Not high compared than my one??
 

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?)
 

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....
audio_bandwidth.PNG

Dont mind Guru, you seems like an indian by name and Chiness by birth!;-)
 
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Class D should have absolutely no problem to realize the sketched frequency response. You never revealed bandwidth requirements along this thread b.t.w.
 

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.
 
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