A Large Active Inductor Emulator for Biomedical Applications

This paper presents a fully integrated and tunable grounded active inductor (GAI) with a high equivalent inductance suitable for biomedical applications such as photoplethysmography (PPG) sensors. The proposed GAI is constructed from a modified 2nd generation current conveyor (M-CCII), a grounded capacitor multiplier (CM), a transconductance amplifier (OTA), and a single resistor. The proposed GAI’s functionality is verified using Cadence in 180-nm TSMC CMOS technology. The simulation results indicate that an equivalent inductance of up to 10 H can be achieved with a relative maximum error of 5 % over an operating frequency range of up to 750 Hz. The proposed GAI occupies a silicon area of 0.0364 mm2 and consumes a power of 34.2 μW when powered from a 1.8 V supply voltage. The proposed design is exploited in designing a bandpass filter with a high-pass corner frequency of 200 mHz and a low-pass corner frequency of 6.4 Hz to filter out 50–60 Hz power lines and biosignals interferences. Monte Carlo statistical analysis and process–voltage–temperature variations have been used to guarantee prototype operation during prospective manufacturing. Furthermore, the comparative table and the figure of merit (FOM) demonstrate that this work is superior to prior arts.