Research On Low Noise And High Gain Instrumentation Amplifiers And Their Switched Capacitor Realizations

With the development of Internet of things,body area network,smart home and Internet of vehicles,sensors are gradually integrated into all aspects of our life.The signal generated by a sensor is usually very small.As the first stage of analog front-end,the instrumentation amplifiers generally have a high gain,so their input referred noise requires to be low enough to ensure high signal-to-noise ratio.An low noise instrumentation amplifier is usually needed before driving an ADC.CMOS devices usually have significant 1/f noise,thermal noise,shot noise,and DC offset.For battery powered sensors,the power dissipation is critical.Therefore the ultra low noise and power efficient instrumentation amplifier is of interest.The thesis first compares four topologies of classic instrumentation amplifiers and evaluates their pros and cons.Due to the inherently lower noise,lower static power dissipation,lower temperature drift,higher precision and rail-to-rail common-mode input voltage range of capacitor based implementation,this thesis focuses on the two capacitor-type amplifiers,the capacitively coupled chopper instrumentation amplifier and the switched-capacitor instrumentation amplifier.Secondly,the thesis describes the spectral transformation mechanism of various noise reduction techniques based on the noise theory,such as chopper stabilization,auto-zero and correlated double sampling.It also compares the pros and cons of these noise reduction techniques combined with the circuit implementations.Furthermore,by using the stochastic process theory,the accurate modeling,calculation and simulation of the kT/C noise formation and the proposed reduction technique in switched-capacitor circuits is presented.In addition,this thesis describes the accuracy consideration of the switched-capacitor circuit and puts forward the compensation scheme.Finally,a novel switched-capacitor instrumentation amplifier based on the common-mode sampling,oversampling,kT/C noise reshaping technique,and ping-pong topology is proposed.The main advantages are(1)The common mode sampling and pseudo sampling technique is used to separate the signal sampling from the kT/C noise sampling and reduce the differential signal-dependent charge injection effect;(2)The low-frequency baseband kT/C noise is modulated to higher frequencies by utilizing the oversampling technique and the kT/C noise reshaping technique,If the sampling frequency of the following ADC is even times of the chopper stabilized frequency,the kT/C noise at the lower frequency is reduced;(3)In addition,ping-pong topology is employed to attenuate the noise folding.In GSMC 0.11-?m process and under a single 3.3-V supply,the switched-capacitor instrumentation amplifier achieves a 5.3-n V/?Hz noise density at low frequency and 500-?A static current consumption with a gain of 32.