two miller compensation pole in the op amp?

[shanmei]

in this kind of class ab amplifer, two miller compensation capacitor in the output
stage? so is will form 2 major pole which are get close in?

anyone knows?

 

[FvM]

I don't see two poles, just two parallel branches.

 

[shanmei]

I don't see two poles, just two parallel branches.

Hi,

But the two gate of the output MOS dosenot connect together?

 

[FvM]

The transistors are operating parallel in signal flow. So it's never two pole. You may want to perform a detailed analysis of the circuit, I'm just talking about principle characteristics.

 

[erikl]

The transistors are operating parallel in signal flow. So it's never two pole.

In order to underline this: I usually use just 1 resistor and 2 caps in such case. And the resistor value then is only half of that of the (otherwise 2) single resistors, which saves 75% of their area. Results in same phase plot.

 

[stpdwsd]

in this kind of class ab amplifer, two miller compensation capacitor in the output
stage? so is will form 2 major pole which are get close in?

anyone knows?

2 major pole is not all right
as to class ab amplifer,one major pole at the time,because two transitors has only one work at the same time

Added after 14 minutes:

in this kind of class ab amplifer, two miller compensation capacitor in the output
stage? so is will form 2 major pole which are get close in?

anyone knows?

hi
can you tell me the front two capacitor what to do

 

[shanmei]

in this kind of class ab amplifer, two miller compensation capacitor in the output
stage? so is will form 2 major pole which are get close in?

anyone knows?

2 major pole is not all right
as to class ab amplifer,one major pole at the time,because two transitors has only one work at the same time

but when the output stage neither sink nor source current, both of the pmos and nmos output are working.

Added after 2 minutes:

in this kind of class ab amplifer, two miller compensation capacitor in the output
stage? so is will form 2 major pole which are get close in?

anyone knows?

2 major pole is not all right
as to class ab amplifer,one major pole at the time,because two transitors has only one work at the same time

Added after 14 minutes:

in this kind of class ab amplifer, two miller compensation capacitor in the output
stage? so is will form 2 major pole which are get close in?

anyone knows?

hi
can you tell me the front two capacitor what to do

I am not so sure, I guess it stablize the bias voltage, I get the pic from somewhere.

Added after 3 minutes:

The transistors are operating parallel in signal flow. So it's never two pole.

In order to underline this: I usually use just 1 resistor and 2 caps in such case. And the resistor value then is only half of that of the (otherwise 2) single resistors, which saves 75% of their area. Results in same phase plot.

the gate of the output PMOS and NMOS connect together in small signal??

 

[erikl]

the gate of the output PMOS and NMOS connect together in small signal??

Yes, but with the "shift zero to LHP" (see here) negative-feedback resistor connected between the 2 caps and the output it's not a shortcut - at least not in the required frequency range. Just compare the Bode plots!

 

[stpdwsd]

in this kind of class ab amplifer, two miller compensation capacitor in the output
stage? so is will form 2 major pole which are get close in?

anyone knows?

2 major pole is not all right
as to class ab amplifer,one major pole at the time,because two transitors has only one work at the same time

but when the output stage neither sink nor source current, both of the pmos and nmos output are working.

Added after 2 minutes:

firstly,the output transistor can work at the same time
but and the time,it has tow poles and two zero,it can stabilization
as to your last opinion,it is not possibile

in this kind of class ab amplifer, two miller compensation capacitor in the output
stage? so is will form 2 major pole which are get close in?

anyone knows?

2 major pole is not all right
as to class ab amplifer,one major pole at the time,because two transitors has only one work at the same time

Added after 14 minutes:

in this kind of class ab amplifer, two miller compensation capacitor in the output
stage? so is will form 2 major pole which are get close in?

anyone knows?

hi
can you tell me the front two capacitor what to do

I am not so sure, I guess it stablize the bias voltage, I get the pic from somewhere.

Added after 3 minutes:

The transistors are operating parallel in signal flow. So it's never two pole.

In order to underline this: I usually use just 1 resistor and 2 caps in such case. And the resistor value then is only half of that of the (otherwise 2) single resistors, which saves 75% of their area. Results in same phase plot.

the gate of the output PMOS and NMOS connect together in small signal??