Design of Three-stage Cascaded Two-Stage Millar Compensated OTA for Wearable ECG Sensor Technologies

Abstract

The use of wearable sensors to monitor vital signs is an alternative to conventional medical systems in hospitals. Patients with wearable sensors can move freely while under continuous monitoring that can stably receive ECG signals, thereby improve the quality of patient care. In this work, a wearable ECG sensor is proposed. The sensor uses a Three-stage Cascaded Operational Transconductance Amplifier (OTA) as an instrument to amplify the ECG signal. The amplifier uses a Two-stage Millar Compensated amplifier integrated with N-Metal-Oxide-Semiconductor and positive-channel-Metal-Oxide-Semiconductor. The simulation results get a CMRR of 66.84 and 3.967μVrms noise and 0.039μW power and 0.981 Noise Efficiency Factor. Compared with the conventional ECG monitoring system, the entire design is smaller in size, and has low power consumption and low noise. It is observed that one can receive ECG signals stably at all times during the experiment. Also, the collected ECG signal is comparable to the ECG signal obtained using conventional adhesive electrodes.