A 400 GΩ Input-Impedance Active Electrode for Non-Contact Capacitively Coupled ECG Acquisition With Large Linear-Input-Range and High CM-Interference-Tolerance

摘要

Electrocardiogram (ECG) is one of the major physiological vital signs and an effective monitoring method for patients with cardiovascular diseases. However, existing ECG recordings require a galvanic body contact, which is unpractical in daily life. This paper presents the design of an ECG chip that facilitates non-contact ECG recording through capacitive coupling. With the input impedance boosting techniques, as well as an active driven-rightleg (DRL) which boosts common-mode rejection ratio to 70 dB, the single-ended capacitive feedback active electrode (AE) achieves ultra-high input impedance of 400G Omega (<0.5 Hz), a large common-mode interference tolerance (2.8 V-PP), and a high linear-input-range (220 mV(PP)). Implemented in 0.18 mu m 5V CMOS process, the prototype occupies an area of 1.23 mm(2), and consumes 18 mu A and 13 mu A for the AE and DRL, respectively. Real life non-contact capacitively coupled ECG acquisition has been demonstrated, obtaining ECG waves and heart rate in the presence of motion artifacts as well as ambient interference.