Instrumentation amplifier input capacitance cancellation for biopotential and bioimpedance measurements

Author

Chun-Hsiang Chang ; Onabajo, Marvin

Author_Institution

Dept. of Electr. & Comput. Eng., Northeastern Univ., Boston, MA, USA

fYear

2014

fDate

3-6 Aug. 2014

Firstpage

539

Lastpage

542

Abstract

An instrumentation amplifier (IA) with a mechanism that generates negative capacitances at its input is presented. The IA architecture includes two digitally programmable (8-bit) capacitors between the input stage and the current feedback loop of the IA to cancel the input capacitances from the electrode cables and printed circuit board. The negative capacitance generation technique can improve the input impedance from a few mega ohms to above 500 MΩ without significant impact on performance parameters such as the common-mode rejection ratio (CMRR), power supply rejection ratio (PSRR), total harmonic distortion (THD), and noise. A 93.6 μW IA was designed and simulated using IBM 0.13-μm CMOS technology.

Keywords

CMOS analogue integrated circuits; bioelectric potentials; circuit feedback; instrumentation amplifiers; printed circuits; CMRR; IA architecture; IBM CMOS technology; PSRR; THD; bioimpedance measurements; biopotential measurements; common-mode rejection ratio; current feedback loop; digitally programmable capacitors; electrode cables; instrumentation amplifier input capacitance cancellation; negative capacitance generation technique; power 93.6 muW; power supply rejection ratio; printed circuit board; size 0.13 mum; total harmonic distortion; word length 8 bit; CMOS integrated circuits; Capacitance; Capacitors; Electrodes; Electroencephalography; Impedance; Instruments; Instrumentation amplifier (IA); bioimpedance measurement; biopotential measurement; input capacitance cancellation; negative capacitance generation feedback (NCGFB); negative impedance converter (NIC);

fLanguage

English

Publisher

ieee

Conference_Titel

Circuits and Systems (MWSCAS), 2014 IEEE 57th International Midwest Symposium on

Conference_Location

College Station, TX

ISSN

1548-3746

Print_ISBN

978-1-4799-4134-6

Type

conf

DOI

10.1109/MWSCAS.2014.6908471

Filename

6908471