Comparative Analysis of Area Efficient Noise Adaptive and Low Power Neural Amplifier using various Topologies

Abstract

The most significant technical challenge in electronics is its integration with Human Brain. Neural cells communicate with each other and generate neural signals which can be used to analyse the brain activity to perform a particular task. The precise monitoring of these signals supported by contemporary integrated circuit technology can enable persons in the locked-in position to use various prosthetic devices effectively besides helping in early neural disorder detection and analysis and efficient brain computer interfaces. The most commonly used non-invasive method to record neural activity by placing electrodes on the scalp is Electroencephalogram (EEG), with an average signal magnitude of 1µV to 100µV occupied in the frequency band from a newlinefraction of 1 Hz to approximately 100 Hz. The electrodes (with jelly or active) are newlinefollowed by the bank of neural amplifiers for signal conditioning. Low power newlineconsumption, lesser area and low noise are the desirable characteristics of typical newlineamplifier used in neural recording channel and the neural amplifier being the first newlinestage, plays a vital role in achieving the required power and noise performance of newlinethe entire system. To structure neural amplifier, Operational Trans-conductance Amplifier (OTA) is the most critical circuit for better amplification and power- reduction. The OTA should be steady and should gather undistorted EEG signal rejecting the offset voltage induced due to the interface between the electrode and the tissue. Different OTA topologies and circuit level topologies have been used for newlineachieving the desirable characteristics. Topologies viz. two-stage, current mirror, newlinetelescopic, folded cascode etc. have been used for OTA design whereas at the newlinecircuit-level, open loop, closed loop and different topologies of the Instrumentation amplifier (IA) are used. Besides, size of transistors used for the design of OTA strongly influences the power, noise and area specifications. However, design tradeoffs of microelectronic systems obstruct the simult