A novel low power MOSFET-C band pass filter for low frequency applications with subthreshold models based on polynomial regression

Abstract

A novel current mode MOSFET-C filter is presented for a wide range of low frequency applications ranging from biomedical signal sensing up to speech processing region. Presented filter consumes only 2.3 µW with symmetrical supply voltages as low as ± 0.5 V. The filter structure can be easily adjusted by means of changing external capacitor values. Furthermore, proposed filter is given with a novel design methodology based on polynomial regressive small signal models. In this way, promising interaction between design parameters such as VGS, VDS, channel width (W), channel length (L) and filter specifications such as f0, Q and power is provided. Simulation results with 0.18 µm TSMC CMOS technology are given, furthermore proposed filter is tested to process a real fetal PCG signal at 355.4 Hz. It is shown that proposed filter attains a promising performance in comparison with the previously presented counterparts for low frequency applications.