A Bandpass Filter with Bootstrapped Source Terminal and Employing Bias Voltage on Gate of Pseudo Resistor for Bio-Signal Sensing

The integrated bandpass filter (BPF) within bio-signal sensing systems forms the critical element for signal detection and pre-processing. This paper presents a BPF with the proposed bootstrapped source terminals of the transistors within the pseudo resistor (PR) and employing an external bias voltage on gates of PR (BSVG-PR), to enhance the impedance of PR and lower the high-pass cut-off frequency. The BPF with BSVG-PR dynamically supports lower biomedical and neural signal sensing. The proposed circuit is designed in a 0.18-µm CMOS process. The proposed BPF with BSVG-PR occupies die areas of 0.008 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>, and achieves high-pass cut-off frequencies of circa 1.0 mHz.