Analyzing very low-energy and low-frequency biomedical signals using a low-voltage-driven and low-frequency signal conditioning circuit provides insight into a person’s health. The proposed work presents a novel low-power signal conditioning circuit designed to accommodate various types of biomedical signals. The circuit consumes 743.95 nW of power, operates with a 1 V power supply, and exhibits a maximum output-referred noise voltage of 1.72 mV/ \(\sqrt{\text {Hz}}\) . It delivers a gain of 15.2 dB with a passband ranging from 35.54 mHz to 2.97 Hz without significant harmonic distortion. The circuit has been designed and its performance has been simulated in Taiwan Semiconductor Manufacturing Company Limited’s (TSMC) 180 nm technology of Cadence Virtuoso Electronic Design Automation (EDA) Tools and uses a two-stage CMOS-based operational amplifier (OpAmp) designed to have 14.62 dB gain, 1.63 \(\mu\) V/ \(\sqrt{\text {Hz}}\) input-referred noise, and 8.93 pW power consumption with a 1 V supply. The input-referred noise and power consumption of the designed OpAmp are lower than those reported in previous literature for supply voltages ranging from 0.5 V to 1.8 V. The complete circuit has been designed and tested to determine the heart rate from a person’s photoplethysmography signal. This circuit can easily be adapted to measure other biomedical signals that require low-frequency, narrow-band signal conditioning.
