CMOS readout electronics for mis-matched and mode-matched MEMS gyroscopes

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2015
Yeşil, Ferhat
This thesis presents the CMOS readout electronics for both mismatched and mode-matched MEMS gyroscopes. A systematic design of MEMS gyroscope's control loop parameters, which is insensitive to sensor parameters and environmental conditions, is necessary for robust and high performance operation. Extra to the systematic design for high performance operation, some special techniques should be used to further increase the performance of the sensor. In this thesis, as a performance increasing technique, mode-matching method is applied to increase the signal to electronic noise ratio. This is achieved by injecting a perturbation signal to the quadrature cancellation loop, while keeping it decoupled from the angular rate control loop. This injected perturbation signal is used to detect the amount of frequency mismatch that is fed to the mode-match controller in order to tune the sense mode resonance frequency by using spring softening effect. This new controller is implemented in a CMOS ASIC together with the other sensor control loops, and it is verified to maintain matched-mode state under changing environmental conditions. The system reduces the overall output noise of the tested MEMS gyroscope by a factor of 6; truly reaching down to the thermo-mechanical noise floor of 0.23 hr)/√Hz. This performance is obtained with 22mm x 22m packaging and 125mW power consumption.

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Citation Formats
F. Yeşil, “CMOS readout electronics for mis-matched and mode-matched MEMS gyroscopes,” M.S. - Master of Science, Middle East Technical University, 2015.