Research And Design On Coarse-Fine Loop Based Instrumentation Amplifier

In recent years,with the rapid development of social economy and the changes of people's lifestyles,more and more attention has been paid to personal health.It is a good way to have a clear understanding of the physical conditions of a particular person by acquiring his/her biological signals.So the research of biological signals attracts lots of attentions,and it has become a hot topic in recent years.Commonly,patients are connected to a bulky and mains powered instrument,which reduces their mobility and creates discomfort,not to mention the capability of real-time monitoring.A lot of efforts have been made to optimize systems' architectures and seek circuits' innovations to realize a real wearable biomedical electronic system.The performance of the analog front-end in biological electronic systems,and more care should be taken of the power dissipation,area of chip,common mode rejection ratio and settling time in the design phase.For wearable devices,it takes a long time to settle down when electrode offset occurs,which always reach several minutes even several hours.A long settling time can not satisfy the requirement of wearable devices.Based on the study of the settling times of other systems when dealing with the electrode offset voltage,an instrumentation amplifier for biological signals acquiring based on coarse-fine loop was proposed in this thesis.Based on the beheaviral modeling and analysis of practical issues in the coarse-fine loop based instrumentation amplifier design,this thesis presents the instrumentation amplifier in 0.18?m CMOS with 1.8V supply voltage.This instrumentation amplifier is capable to handle the electrode offset voltage up to ±75mV,and can settle down within 4.5 seconds.More than 132 dB common mode rejection ratio and 62.2 nV??? noise power density are obtained,and the integral noise in 0.5-100 Hz signal band is 843.6V_rmsn.