Hi everybody
Currently i am having some questions about classD amplifier circuit. This is a diagram of the principle that I have found
http://www.upsieutoc.com/image/In2O2j

but I do not understand where the circuit creates the triangular pulse?
please help me

 

Whatsa 2110? Over 3.3 million entries on Google. Where is the triangular wave? Redraw the schematic so that only the necessary parts are shown, as is it hurts my head. E

 

Hello,

@Nykolas , the 2110 mentioned in the schematic looks like a basic halfbridge (high side & low side) driver IR2110.
I also see not where the PWM is generated.

Bertus

 

Hi everybody
Currently i am having some questions about classD amplifier circuit. This is a diagram of the principle that I have found
http://www.upsieutoc.com/image/In2O2j

but I do not understand where the circuit creates the triangular pulse?
please help me

You'll have to remind me whether the TL071 is single or dual - I'd usually expect one op-amp to be wired as a triangle generator and the other as a comparator..

The comparator compares the signal with the rising and falling triangle and the output is pretty much the M/S ratio.

 

I have not done any serious analysis. But here goes:
There is feedback from the output FET's clear back to the summing input of the op-amp. I am guessing that the RC network in the feedback of the op-amp is causing an oscillation that is compared to the PWM signal from the FET's.

Pretty handwavey, I admit. I am waiting for all of the detailed explanations that prove me wrong. That way I will have learned something.

(I am having a hard time keeping from spending a lot of time doing an LTspice simulation of a simplified version of the circuit.)


@ian field : the TL071 is a single.

 

Easy to remember:
TL071 is single
TL072 is dual
TL074 is quad

same thing for:
TL081
TL082
TL084

 

I have not done any serious analysis. But here goes:
There is feedback from the output FET's clear back to the summing input of the op-amp. I am guessing that the RC network in the feedback of the op-amp is causing an oscillation that is compared to the PWM signal from the FET's.

Pretty handwavey, I admit. I am waiting for all of the detailed explanations that prove me wrong. That way I will have learned something.

(I am having a hard time keeping from spending a lot of time doing an LTspice simulation of a simplified version of the circuit.)


@ian field : the TL071 is a single.

I caught on a split second after clicking post reply - that's what the final digit means. Its been a while...........

 

i need a link to upload my picture. please help me

 

i need a link to upload my picture. please help me

Save your image to your computer.
Click on Upload a File in the Post Reply window.

 

thank u very much, Here is my picture I found.
but i dont understand how it operate?

 

I removed feed back from output and input signal then simulate it on PSIM

how to it oscilate?
everyone help me please

 

It looks like they left a couple of parts off the schematic.

If you add a resistor and capacitor to the 4049 you will make it into an oscillator.

The 2N5401 is connected as a current source that is modulated by the audio from the TL071. Adding this current to an input of the oscillator causes duty cycle modulation.