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 0.18)tm CMOS process with a 1.8 V supply. Under power consumption of 16.7pAV, measurement results show that 2OVpp CMI with a frequency range spanning from 2011z to 80Hz is suppressed below 200mVpp that guarantees the normal operation of subsequent instrument amplifier. Also, the input -referred noise (IRN) within 100Ilz and common -mode rejection ratio at 501Iz are 1.2607,,,, and 91dB, respectively.