System Stability Analysis Of The Closed-loop Microaccelerometer From Interface Circuit

Based on analyzing the principle of the closed-loop micro accelerometer and dynamic characteristic, the analysis and optimization, including the effect from non ideal analogue unit, structural damping, sequence circuit and harmonic distortion, is presented in this thesis.The imperfect analogue unit can be classified in three main groups: the moment voltage, leading amplifier and imperfect switch. First of all, the effect of the system output from the moment voltage on frequency and amplitude is presented in the thesis, Second, the dissertation separately discusses the effect of system stability from offset voltage, slew rate and bandwidth in leading amplifier. The way of reducing system offset is presented. At last, the non ideal factor of analog switch is analyzed. By Hspice, get right switch dimension.The structural damping mainly contains squeeze damping. The relation between damping and the distance of polar plate, temperature, sensitivity is analyzed. In theory the reason, which the noise of the loop-oscillator in sequence circuit makes system instability, is discussed. And show the expression between them.The system harmonic distortion is the second harmonics and third harmonics distortion. Analyze harmonic distortion in open and close complexion, and get that the second is great the third harmonics. Using compensation capacity array, reduce asymmetry capacity. By testing when the capacity offset is 0.02% and 0.2%, the second harmonics is individually 0.009% and 0.042%.