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Slew rate in feedback

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quaternion

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What is the effect of negative feedback on slew rate of an amplifier within the feedback loop ?

And if the amplifier has a pole zero doublet what happens to it (I guess that separation between the pole and the zero increases ) ?
 

nagetive feedback stabalize the system where slew rate means how much output follows the input,totally independent of each other,kindly write your second question more explicitly.
tc
 

for the second question,you can read the IEEE paper:
Relationship between frequency response and settling time of operational amplifiers

it will ruins the settling time
 

The transient response of an amplifier has two components:-
slew rate limited which is present approx till output reaches 70-80% of final settling value.
bandwidth limited, which will limit the remaining time fot it to settle and is depenedent on bandwidth.
When we play around with gain and compensation we keep on tweaking the bandwidth limited component only.
The slew rate limited component is totally decided by input value(change) and output current.
But for fixed current spec we need to balance the distribution between first differential stage(determines bandwidth) and 2nd stage(determined slew rate). Thus making it dependent on each other.
Hope this helped.

Supreet
 

@sunbeam

Could you please upload this paper somewhere?

Thanks in advance
F.F. a.k.a. Powermos
 

quaternion said:
What is the effect of negative feedback on slew rate of an amplifier within the feedback loop ?

And if the amplifier has a pole zero doublet what happens to it (I guess that separation between the pole and the zero increases ) ?
Click to expand...

To 1): Of course, feedback influences the slew rate SR.
Mostly, SR is defined for unity gain feedback.
Explanation: The slew rate effect results from saturation of the first stage when the input signal changes rapidly, and because the feedback cannot respond immediately to bring the first stage back to the linear region.

To 2): The effect of a pole-zero pair is to cancel each other with the result that the amplitude reponse is less steep and, therefore, more stable in case of feedback.
 

what does it mean by pole zero doublet?does it mean both lie in same location?if yes they will cancel each other like wise in case of all pass filter that it'll never show any attanuation at any frequency,it will just effect the phase
 

Yes, they cancel each other. This is called also "pole-zero-compensation".
 

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