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hi,everyone!
I recently learnt root locus method, but there was a problem when I applied this method to analysis the basic two stage miller compensation amplifier without zero nulling. I used two port method neglecting the compensation capacitor feedforward signal to calculate the loop gain...
Hi,all.
Now I think the overshoot is due to high damping factor of the nondominate complex poles and the zeros have little effect which is different from previous thought.
thanks.
hello,everyone. I have figured this problem out recently after acquiring the basic knowledge of control theory. I used two port method to compute the loop gain transfer function and find there are four low frequency poles and one zero locating at origin due to feedforward path and feedback path...
Because these are two poles right after the two zeroes, so it seems these is only one zero. If I modify the zeroes to a lower position, the peaking will be quite obvious.
---------- Post added at 11:11 ---------- Previous post was at 10:50 ----------
Hello, FvM. Nice to hear from you again.
I...
Hello， I think after this type of compensation the RHP zero introduced by Cc path is really high.
There must be some other path that introduce the RHP and LHP zeroes.
In my simulation, the symmetric zeroes are before the non-dominant pole and after the unity gain bandwidth.
So they don't...
Actually, these are a RHP zero and a LHP zero in the type of Ahuja compensation . Anyone who has the same question could refer to "Issues in “Ahuja” Frequency Compensation Technique ".
With regarding to the improvement as gevy sad, I could not understand yet.
Hope someone could give me some...
I have just tried the method as gevy sad . Though the total value of compensate capacitor are same , the RHP and LHP zeroes indeed move to a higher position with the poles nearly unchanged. So the stability gets better.
As for the problems that you have sad ,I would agree with you before the...
Hi, everyone!
For the op-amp compensated in the way as follows, there is a RHP zero a LHP zero lower than the nondominate pole.
That makes it difficult to compensate , so i wonder which position introduces the zeroes and whether there is someway to modify the zeroes to a higher position.
Thanks...
thanks,maybe i should try to cancel the intermediate voltage shift stage and find what will happen.
---------- Post added at 17:18 ---------- Previous post was at 17:08 ----------
It seems I have a lot of complicated work to do.
I have learned so much from all of you.
thanks very much.
hi, i don't understand why the circuit could be unstable when the phase jump is positive.
Doesn't instability always happen in the close loop circuit?
---------- Post added at 10:23 ---------- Previous post was at 10:13 ----------
there are two RHP plural poles in the DM transfer function.
I...
hello all,i have just got back from the national day.
i tried other kinds of test bench, however the simulation kept unchanged.
here i post the main opamp circuit and hope someone can give me some suggestion.
thanks
hello,everyone
the plot is the open loop gain and phase versus frequency and the close loop gain is 18.however, i have many confusions about it.
1:what is the phase margin when the feedback factor is 1/18?
2:Does the overshoot cause close loop instability?
3:Is it common to see the phase never...
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