left half and right half zero

[manissri]

HOw the left and right half zero is produced in analog circuits.

 

[flatulent]

Bridge circuits are frequently used.

 

[jiangxb]

using miller capacitor creates right-plane zero, and adding nulling resistor moves the right-plane zero to left-plane.

 

[manissri]

my question is that how rigth half and left half zero is produced
like in two stage amp signal goes to output from two path one from miller cal and one from mosfet then at some frequency these signal cut to each other hence a right half zero is produced.
now my question ?
why this zero is on right half plane why not in left half plane ,
i want to know the mechanism of producing right and left half plane zero

 

[LvW]

my question is that how rigth half and left half zero is produced
like in two stage amp signal goes to output from two path one from miller cal and one from mosfet then at some frequency these signal cut to each other

Who told you that a left hand zero is produced ? It isn´t true.
The mechanism as desribed by you (two signal paths to the output of the transistor) creates a zero in the right hand plane as well as a pole in the left hand plane (equivalent to a zero of the transfer function denumerator).

However, the zero in the right hand plane is a real one. That means, that both parts of the signal cannot cancel each other ! There is only a certain reduction - depending on the frequency and the C value.

 

[manissri]

Thz luw,
but i read in books that if two signal comes in opposite phase then right half zero would produced like two stage amp where two signals reach at the output of amp in opposite phase 1 - in same phase through miller cap at high frequency
2. from mos transistor which is in opposite phase.
the other case if u take source follower circuti.
where two signal reach in same phase
1. through mos transistor (same phase ) as this is source follower
2. through the Cgs (also in same phase ) at the output
hence the left half zero produced
regards

 

[LvW]

Thz luw,
but i read in books that if two signal comes in opposite phase then right half zero would produced

But the two signals are not in opposite phase due to the capacitive phase shift.
Therefore, both parts cannot really cancel each other.

 

[manissri]

Hi Lvw,,
at high frequency the capacitor acts as the short wire hence same phase of signal u will get at the output

 

[LvW]

OK, if they are nearly in opposite phase, the amplitudes never will be equal to compensate each other.

 

[manissri]

hi LvW,
thaz for ur answer.
but again my same question hwo left half zero develops
as if u read the Razavi book what ever i commented it is only from that book..

 

[LvW]

but again my same question hwo left half zero develops
as if u read the Razavi book what ever i commented it is only from that book..

As already mentioned in my reply dated 25th of June (19:52), there is no zero in the left hand s-plane. It is a pole (i.e. a zero of the transfer function denumerator)