michaelhust
Junior Member level 1
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 transfer function 2. There were two LHP poles and one zero locating at origin. This could explain the poles splitting properly applying root locus method.
However, when the feedforward signal of compensation capacitor was included, there was another RHP zero in the transfer function 1 which would trend to make the poles go to RHP.
What's wrong with my calculation? Thank you.
![QNEV5DAL8Z]71$EKYRHP4{7.jpg](https://www.edaboard.com/data/attachments/16/16550-6ad239b1eb36eae7483f94bd0b7eb439.jpg "QNEV5DAL8Z]71$EKYRHP4{7.jpg")
![6~]9N[_9Q0OPM(C6HJ}5~N0.jpg](https://www.edaboard.com/data/attachments/16/16552-c6d4c7b9b0a7404ea0e4d33632969d03.jpg "6~]9N[_9Q0OPM(C6HJ}5~N0.jpg")
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 transfer function 2. There were two LHP poles and one zero locating at origin. This could explain the poles splitting properly applying root locus method.
However, when the feedforward signal of compensation capacitor was included, there was another RHP zero in the transfer function 1 which would trend to make the poles go to RHP.
What's wrong with my calculation? Thank you.
