A Low Power Variable Gain Amplifier for Biomedical Application

Abstract

This paper describes the design and simulation of low power variable gain amplifier used for biomedical application like hearing aid, Electronic Cardiograph and neural recording system. The MOS transistor is designed to operate in subthreshold region for low power application. The gain of amplifier is changed by selecting different values of input capacitor in the frequency range of 20 Hz–20 KHz. The simulated total power dissipation is 3µW. The gain variation is from 10–30 dB with supply voltage of 1.8V in TSMC 0.18 µm process using mentor graphics.

Keywords: Weak inversion, strong inversion, miller compensated opamp, hearing aid, variable gain amplifier