A Low Noise, Low Power Readout Front-End Analysis for Biomedical Applications using CMOS Technology

As biopotential signals are having very small frequency variations tens of Hz and micro to millivolts amplitude in the range.While acquiring biopotential signals from a human body, intrusions occur in the acquisition system.Thus, for acquiring noise-free signals, the enhanced Biopotential Acquisition unit having a high gain with an improved common-mode rejection ratio readout front-end is designed.To solve mentioned issues, an improved front end is introduced in this paper to achieve high DC gain and high Unity-gain frequency.The proposed front-end operates at 0.2 V supply voltage, the bias current of 20A, and achieves a high gain of 74dB.The design comprises a miller frequency compensation structure by connecting a capacitor across a high voltage stage and the load capacitor is connected across output by following the relation of CC > 0.22 CL.The proposed high gain stage achieves additional gain with reduced noise of 0.2 mV/ with a minimal power consumption of 1.9 nW.The analog readout front-end is executed using 180 nm CMOS Technology and utilizes less power, making it ideal for battery-powered devices in Biopotential Acquisition systems.The final section includes a comparison of the proposed front-end with various amplifiers.