Reseach On Sigma-Delta Technology And It's Application On Electrostatic Microgyro

The application of the MEMS technology in the field of inertial devices bloomed the micro machined gyroscope and accelerometer. The electrostatically levitated micro gyro has the feather of low power, low drift, high precision. It has a wildly application in the field of missile, satellite, munition, et al. A kind of electrostatic levitated micro rotor based on UV-LIGA technology has been proposed, it consists one rotor and two stators. Through four pairs differential capacitance, the micro gyro can sense two-axial angular rate and three-axis linear accelerometer.The detection circuit for differential capacitance usually consists of modulation-demodulation, amplifier and filter. Recently, sigma-delta technology used in A/D conversion has been matured. When it is used in the detection of differential capacitance, it has following advantage: super system stability; a direct digital signal output; an inherent self-test feature. This paper builds a control model for electrostatic levitated micro rotor based on the sigma-delta technology. It has been designed and simulated through Matlab/Simulink. Finally, a two-order sigma-delta modulator has been designed through TSMC 0.25um technology.This paper introduce the structure and dynamic model of the electrostatically levitated micro rotor, and a control model for electrostatic levitated micro rotor based on sigma-delta technology. It has been designed and simulated through Matlab/Simulink. Then, through Orcad/Pspice, a Pspice model for differential capacitance has been proposed and simulated, the results show that, the detection circuit has a sensitivity of 2V/g and a dynamic measurement range of approximately±1g.A sigma-delta modulator referred to as a reduced-integrator-swing-rage (RISR) modulator was investigated. This RISR topology greatly reduces the input and output swings of integrators, which is favorable at low supply voltage. Then, a two-order sigma-delta RISR modulator has been designed and simulated by Cadence/Spectre base on TSMC 0.25um technology.