Title :
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
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;
Conference_Titel :
Electronics, Circuits and Systems, 1998 IEEE International Conference on
Conference_Location :
Lisboa
Print_ISBN :
0-7803-5008-1
DOI :
10.1109/ICECS.1998.814006
