| Summary: | 碩士 === 逢甲大學 === 電子工程學系 === 103 === This paper presents a low-power analog front-end (AFE) circuit with a high common-mode rejection ratio (CMRR) for measuring physiological signals (electrocardiograms and electroencephalograms). The whole AFE circuit comprises a high CMRR differential difference instrumentation amplifier (DDIA), a high-pass filter (HPF), a low-pass filter (LPF), and a notch filter.
DDIA is responsible for receiving physiological signals and noise, providing 48.2 dB gain, and utilizing the common mode feedforward (CMFF) circuit, which enables the DDIA to reach 133 dB CMRR.
The differential amplifiers HPF and LPF and notch filter, with active current mirror load, can filter out the physiological signals and interference noises outside the desired bandwidth (0.1–400 Hz). The bias current of the differential amplifier is designed at 300 nA or less, and therefore, the total power consumption of the AFE circuit is less than 8 μW. The proposed AFE circuit is simulated and validated by the Taiwan Semiconductor Manufacturing Company Limited (TSMC) Silicon Germanium (SiGe) 180 nm BiCMOS process technology with an operating voltage of ±1 V.
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