A micropower dry-electrode ECG preamplifier

This paper describes the development of a very low-power preamplifier intended for use in pasteless-electrode recording of the human electrocardiogram. The expected input signal range is 100 /spl mu/V-10 mV from a lead-II electrode configuration. The amplifier provides a gain of 43 dB in a 3-dB bandwidth of 0.05 Hz-2 kHz with a defined high input impedance of 75 M/spl Omega/. It uses a driven common electrode to enhance rejection of common-mode interfering signals, including low-frequency motion artifact, achieving a common-mode rejection ratio (CMRR) of better than 80 dB over its entire bandwidth. The gain and phase characteristics meet the recommendations of the American Heart Association, ensuring low distortion of the output ECG signal and making it suitable for clinical monitoring. The amplifier has a power consumption of 30 /spl mu/W operating from a 3.3-V battery and is intended for use in small, lightweight, portable electrocardiographic equipment and heart-rate monitoring instrumentation.

[1]  M. P. Watts,et al.  Trends in electrocardiograph design , 1987 .

[2]  P. Macfarlane,et al.  Recommendations for standardization and specifications in automated electrocardiography: bandwidth and digital signal processing. A report for health professionals by an ad hoc writing group of the Committee on Electrocardiography and Cardiac Electrophysiology of the Council on Clinical Cardiology, , 1990, Circulation.

[3]  Ramon Pallas-Areny,et al.  Common mode rejection ratio for cascaded differential amplifier stages , 1991 .

[4]  John G. Webster,et al.  Driven-right-leg circuit design , 1983, IEEE Transactions on Biomedical Engineering.

[5]  J G Webster,et al.  60-HZ interference in electrocardiography. , 1973, IEEE transactions on bio-medical engineering.

[6]  Nitish V. Thakor,et al.  Ground-Free ECG Recording with Two Electrodes , 1980, IEEE Transactions on Biomedical Engineering.

[7]  H V Pipberger,et al.  The low-frequency response of electrocardiographs, a frequent source of recording errors. , 1966, American heart journal.

[8]  J. Webster,et al.  Minimizing Electrode Motion Artifact by Skin Abrasion , 1977, IEEE Transactions on Biomedical Engineering.

[9]  P Zipp,et al.  A model of bioelectrode motion artefact and reduction of artefact by amplifier input stage design. , 1979, Journal of biomedical engineering.

[10]  John G. Webster,et al.  Reductionl of Interference Due to Common Mode Voltage in Biopotential Amplifiers , 1983, IEEE Transactions on Biomedical Engineering.

[11]  George E. Bergey,et al.  Electrocardiogram Recording with Pasteless Electrodes , 1971 .

[12]  M.R. Neuman,et al.  Insulated Active Electrodes , 1970, IEEE Transactions on Industrial Electronics and Control Instrumentation.

[13]  D. Tayler,et al.  Signal Distortion in the Electrocardiogram Due to Inadequate Phase Response , 1983, IEEE Transactions on Biomedical Engineering.

[14]  J. Webster,et al.  Common mode rejection ratio in differential amplifiers , 1991 .

[15]  H V Pipberger,et al.  Electrocardiographic distortions caused by inadequate high-frequency response of direct-writing electrocardiographs. , 1967, American heart journal.