Offset cancellation with subthreshold-operated feedback circuit for fully differential amplifiers

Author

Iida, Tomoki ; Asai, Tetsuya ; Sano, Eiichi ; Amemiya, Yoshihito

Author_Institution

Dept. of Electr. Eng., Hokkaido Univ., Sapporo, Japan

fYear

2009

fDate

13-16 Dec. 2009

Firstpage

140

Lastpage

143

Abstract

An offset cancellation technique for fully differential amplifiers is proposed. This technique uses subthreshold-operated operational amplifiers (subth-OP amps) for feedback biasing. Two subth-OP amps sense the two outputs of the differential amplifier and accordingly adjust the load currents in the amplifier to fix the outputs to a given reference voltage. The feedback operation is established only at dc and low frequencies because the subth-OP amps operate very slowly. The differential amplifier consequently operates as a high-pass filter and therefore shows no dc offset in its output, while it can normally amplify ac input signals. The results for the simulation and fabrication of the device are described.

Keywords

differential amplifiers; feedback amplifiers; high-pass filters; operational amplifiers; ac input signals; fully differential amplifiers; high pass filter; load currents; offset cancellation; operational amplifiers; reference voltage; subthreshold operated feedback circuit; Circuit simulation; Circuit topology; Differential amplifiers; Fabrication; Feedback circuits; Filters; Frequency; MOSFETs; Operational amplifiers; Threshold voltage;

fLanguage

English

Publisher

ieee

Conference_Titel

Electronics, Circuits, and Systems, 2009. ICECS 2009. 16th IEEE International Conference on

Conference_Location

Yasmine Hammamet

Print_ISBN

978-1-4244-5090-9

Electronic_ISBN

978-1-4244-5091-6

Type

conf

DOI

10.1109/ICECS.2009.5410959

Filename

5410959