A continuous-time common-mode feedback circuit (CMFB) for high-impedance current mode application

Author

Luh, Louis ; Choma, John, Jr. ; Draper, Jeffrey

Author_Institution

Dept. of Electr. Eng., Univ. of Southern California, Los Angeles, CA, USA

Volume

3

fYear

1998

fDate

1998

Firstpage

347

Abstract

A continuous-time common-mode feedback circuit (CMFB) is presented. A two-stage high-gain architecture is used to minimize the offset of the common-mode voltage. A special compensation scheme enables this circuit to be used in high-impedance current-mode systems without a stability problem. Simulation and testing results show the superior performance of this circuit. It is proven to be an ideal common-mode feedback circuit for systems which require an accurate and stable common-mode voltage. This circuit has been implemented in a continuous-time switched-current ΣΔ modulator with a 2 μm CMOS process. With a 50 MHz clock, the modulator has achieved a 60 dB dynamic range in a 1 MHz bandwidth

Keywords

CMOS analogue integrated circuits; analogue processing circuits; circuit feedback; circuit stability; continuous time systems; current-mode circuits; modulators; sigma-delta modulation; switched current circuits; 1 MHz; 2 micron; 50 MHz; CMOS process; common-mode feedback circuit; common-mode voltage offset; compensation scheme; continuous-time ΣΔ modulator; continuous-time circuit; high-impedance current mode application; sigma-delta modulator; stability; switched-current ΣΔ modulator; two-stage high-gain architecture; Bandwidth; CMOS process; Circuit simulation; Circuit stability; Circuit testing; Clocks; Dynamic range; Feedback circuits; Switching circuits; Voltage;

fLanguage

English

Publisher

ieee

Conference_Titel

Electronics, Circuits and Systems, 1998 IEEE International Conference on

Conference_Location

Lisboa

Print_ISBN

0-7803-5008-1

Type

conf

DOI

10.1109/ICECS.1998.814006

Filename

814006