A 1-V CMOS preprocessing chip for ECG measurements

In this work, a low-voltage, low-power signal processing chip for ECG measurements has been designed and manufactured. The circuit includes a continuous time, offset-compensated preamplifier with amplification of 40 dB, an 8^th-order Butterworth switched-opamp, switched-capacitor (SO-SC) filter with a passband of 8 Hz - 30 Hz, a 32-kHz crystal oscillator, an SO-SC postamplifier and a bias circuit. The whole circuit operates with supply voltages of 1 V - 1.8 V and the average current consumption is only about 3 μA. Therefore, the circuit is very suitable for portable applications, like heart rate detectors.