A decoupling-capacitor free and enlarged-ICMR ECG readout circuit using offset feedback cancelling and charge pump-sustained input stage techniques

This paper presents an improved indirect feedback instrumentation amplifier for reading ECG signals. The circuit uses a charge pump module and an integral feedback offset suppression module. The input common mode range (ICMR) is extended, and the electrode offset and baseline drift in the ECG signal are suppressed. The circuit is designed by using 0.18μm CMOS process. The simulation shows that the circuit can operate at the input offset voltage 200mV at the 2V supply voltage. The input common mode range is 0∼3.4v, the gain is 46dB, the power consumption is 121.6μW, and the common mode rejection ratio is 124dB.