Lets take a look on a linear amplifier

[MD MUBDIUL HASAN]

Your current amplifier input has a 13k resistor in series with a 1k resistor to ground then it attenuates the signal to 1/14th its original level. Why?
Why are you using transformers?

Yes, I am thinking about this issue. Because of transformer ! What kind of load it is carrying ? We also saw, RC element at output. Is there any way that high frequency componet returns!

 

[MD MUBDIUL HASAN]

you need thermal compensation to control the idle current in the output stage. silicon transistors have a negative temperature coefficient, so the Vbe is reduced 2.2mV for every deg C of temperature increase. if the bias voltage remains the same, this turns on the transistor on harder, increasing the idle current, and increasing the temperature even more. the cure for this is a bias clamp, which acts like an adjustable zener diode. the transistor in this bias circuit is usually mounted on the heat sink between the output transistors so that it can compensate for the change in temperature by reducing the bias voltage of the output transistors.

Can you suggest a similar IC for classD?

 

[MD MUBDIUL HASAN]

The transformers caused phase shifts.

Wish to know more!

 

[MD MUBDIUL HASAN]

Have you ever seen an audio amplifier with a bandwidth of only 45-65Hz? - that fact alone means it's not an audio amplifier.

Offcourse its not!
Intention of amplifier may be more or less same!

 

[audioguru]

The series RC at the output of most audio amplifiers is called a "Zobel network". Look it up.
It helps an amplifier prevent instability oscillation caused by the inductance of a speaker causing a high load impedance at high frequencies.

Texas Instruments (and most other IC manufacturers) has a website. If you select "Class-D Audio Amplifiers" then they will give you a list of many of their ICs that do it.

A transformer causes a phase shift at low frequencies caused by its inductance. The phase shift is reduced at low frequencies if its size is increased.
A transformer causes a phase shift at high frequencies caused by stray capacitance along its windings and coupling between its windings.

Many cheap audio systems have two stereo speakers and one "sub-woofer". They make the "sub-woofer" amplifier produce only 45Hz to 65Hz to fool people that it produces bass sounds. My stereo system does not have a sub-woofer speaker and amplifier so I designed and built a circuit that boosts frequencies between 30Hz and 70Hz to do it with my ordinary woofers.

 

[MD MUBDIUL HASAN]

It helps an amplifier prevent instability oscillation caused by the inductance of a speaker causing a high load impedance at high frequencies.

Yes! that was I asking for!
Now trying to calculate total load current, voltage, power specifications.
Then we can look on TI/AD,,,ETC.

 

[MD MUBDIUL HASAN]

Class D IS pwm!

Just with a supersonic carrier frequency, so when filtered after the power stage, the mean level of the PWM modulated signal is left, which is the audio.

Block diagram of a Class D amplifier; a PWM generator, power switching stage and output filter:

https://www.researchgate.net/profile/Krit_Salah-Ddine/publication/303685974/figure/fig2/AS:367844568125441@1464712387083/Class-D-Amplifier-Waveforms.png

High current and voltage are not a problem - eg. this driver IC can operate a pair of power FETs as up to 500V and controlling thousands of watts, from logic level signal inputs:
**broken link removed**

REQUIRMENTS :

1. The amp input should be plus and minus 7volt AC, 45-65Hz( 1 Hz has been converted to 1024)

2. Amp operating voltage should be more or less 24v.

3. 2 channel signal (not sure PWM) should be use , one for current, one for voltage.

4.Can run current transformer(input 16.5 V/1.5 A) and potential Transformer (input15v/2A).

5. If possible both voltage and current amplification is required in one IC.

 

[audioguru]

The supply voltage and load impedance determine the maximum undistorted output power.
A stereo audio power amplifier IC can use one channel for your voltage amplification and use the second channel for your current amplification.

 

[MD MUBDIUL HASAN]

The supply voltage and load impedance determine the maximum undistorted output power.
A stereo audio power amplifier IC can use one channel for your voltage amplification and use the second channel for your current amplification.

Could you kindly read this attached datasheet from TI once?
Dont you think this IC could be use?https://www.ti.com/product/TPA3118D2?qgpn=tpa3118d2

 

[audioguru]

You did not say the load impedance, the supply voltage you will use and how much undistorted output power you need.
The output power is much more when one IC is used BTL with only one output.

 

[MD MUBDIUL HASAN]

You did not say the load impedance, the supply voltage you will use and how much undistorted output power you need.
The output power is much more when one IC is used BTL with only one output.

current transformer(input 16.5 V/1.5 A) and potential Transformer (input15v/2A)

There are three ways to explain Percentage Impedance:
This drop (or rise with leading loads) depends on the X/R ratio of transformer and PF of the load. % voltage drop= %R cos phi +% X sin phi where cos phi is the PF of load. 2) It is the %voltage required on primary to circulate rated current on a shorted secondary

 

[MD MUBDIUL HASAN]

The output power is much more when one IC is used BTL with only one output.

Typical Differential (2N) AD-Mode BTL Application

At least go through this datasheet and now forget about particular TR impedances, switching, frequencies etc.
https://www.ti.com/product/TPA3220

 

[audioguru]

The datasheet for the TPA3220 recommends a max power supply voltage of 30V and shows stereo outputs of 50W continuously into 8 ohms for both channels.
The datasheet shows higher power with higher distortion of 10% and when the loads are 4 ohms and also shows much higher power for short durations before it shuts down due to over-temperature.

The schematic shows output LC lowpass filters that remove the 480kHz switching frequency.

 

[tvtech]

Audio....this poster is gonna drive you nuts.
It's not worth it.

 

[audioguru]

Audio....this poster is gonna drive you nuts.
It's not worth it.

Yeah. He doesn't know what he is doing and I also don't know what he is doing.

 

[MD MUBDIUL HASAN]

Audio....this poster is gonna drive you nuts.
It's not worth it.

If I were you, I would avoid this post.
Can you show any hints of this topic that you have contributed?

 

[MD MUBDIUL HASAN]

Yeah. He doesn't know what he is doing and I also don't know what he is doing.

Looking at TI suggested TPA3220 EVM,

LC filter is visible here! I wont ask you why its connected.
In my case, the primary side of transformer impedance was 0.00117ohm.

While it was connected to Class AB output , a 10 ohm along with 0.33uF in series RC grounded filter was connected parallay to its primary.

Now talk about SC protection of 60 Hz step up transformer in this case.

 

[audioguru]

0.00117ohm is a dead short. An audio amplifier is designed to drive 4 ohms to 16 ohms.
On one of the other forms you talk about this project you said the primary of the transformer is 15V with a current of 2A then its impedance is 7.5 ohms.

 

[tvtech]

K

 

[MD MUBDIUL HASAN]

0.00117ohm is a dead short. An audio amplifier is designed to drive 4 ohms to 16 ohms.
On one of the other forms you talk about this project you said the primary of the transformer is 15V with a current of 2A then its impedance is 7.5 ohms.

Yes! 7.5 ohm. One 10 ohm plus 0.33 uF ( at higher frequency it will be short) was connected before primary.


Hope you would have good idea about " 3 phase calibration" those I have showed you in other forum. Its a normal reason to chose 45Hz ~ 65 Hz. You have explain that curve well, but one thing you have missed that " wave lenght", full cycle " Time period" and " frequency" has close relation in Physics.

I wanted to see a " slow" electrical wave where " power qualities" are visible. Its a " common sense" other than "thinking "copied" from others!