An Adaptive Common-Mode Cancellation Biopotential Amplifier for Two-Electrode Dynamic ECG Recording

This paper presents a novel adaptive common-mode Cancellation Biopotential Amplifier for portable ECG recording. The amplifier features a converge-free adaptive common-mode cancellation (ACMC) loop with nine MOSFETs, two capacitors, two pseudo resistances and one unity gain buffer. Through periodic detecting and compensating common charge induced by common-mode interference (CMI), ACMC circuit is able to suppressed amplitude of CMI over 100x without requiring a convergence process or additional common-mode references. To verify the design, a prototype is fabricated in 0.18μm CMOS process with a 1.8 V supply. Under power consumption of 16.7μW, measurement results show that 20V
PP
CMI with a frequency range spanning from 20Hz to 80Hz is suppressed below 200mV
PP
that guarantees the normal operation of subsequent instrument amplifier. Also, the input-referred noise (IRN) within 100Hz and common-mode rejection ratio at 50Hz are 1.26μV
rms
and 91dB, respectively.