Inductive compensation of operational amplifiers in feedback circuits

In this thesis I designed, implemented, and tested an integrated-circuit feedback compensator that uses inductors as compensation elements. Introducing inductors as feedback elements makes it possible to implement lead compensators using shunt topologies, which preserve the closed loop response of a system while compensating the open loop characteristics. My chip consisted of a marginally unstable two-pole amplifier, and a compensated but otherwise identical amplifier. Comparing the step responses of the original and compensated systems proved that the compensator successfully stabilized the unstable system. I used frequency domain analysis to determine how much phase margin my compensator added to the system. After characterizing and canceling out the effects of input and output loading, and the attenuation of my output buffer, I found that my compensator added 41.40 of phase to the system. This was less than the 65° that it was designed for, but more than enough to prove the feasibility of my design.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2010

Author dc:creator

• Adams, Douglas Jay Kozak

Advisor dc:contributor.advisor

• Rahul Sarpeshkar.

• Electrical Engineering and Computer Science.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/76117

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/76117