Advanced readout and control electronics for mems gyroscopes

Temiz, Yüksel
This thesis reports the development of advanced readout and control electronics for MEMS gyroscopes developed at METU. These gyroscope electronics are separated into three main groups: high sensitive interface circuits, drive mode amplitude controlled self oscillation loops, and sense mode phase sensitive amplitude demodulators. The proposed circuits are first implemented with discrete components, and then integrated on CMOS chips. A self oscillation loop enabling constant amplitude drive mode vibrations independent of sensor parameters and ambient conditions is developed. A fully functional angular rate system, which is constructed by employing this advanced control electronics together with the transresistance amplifier type interfaces and sense mode electronics, is implemented on a dedicated PCB having 5.4x2.4 cm2 area. This system demonstrates an impressive performance far better than the best performance achieved by any angular rate system developed at METU. Bias instability and angle random walk values are measured as 14.3 º/hr and 0.126 º/√hr, respectively. The scale factor of the system is found as 22.2 mV/(º/sec) with a nonlinearity of 0.01%, and a zero rate output of 0.1 º/sec, in ±50 º/sec measurement range. CMOS unity gain buffer (UGB) and transimpedance amplifier (TIA) type resistive and capacitive interfaces are characterized through AC, transient, and noise tests. It is observed that on chip biasing mechanisms properly DC-bias the high impedance nodes to 0 V potential. UGB type capacitive interfaces demonstrate superior performance than TIA counterparts due to stability problems associated with TIA interfaces. CMOS differential drive mode control and sense mode demodulation electronics give promising results for the future performance tests.


Design and fabrication of rf mems switches and instrumentation for performance evaluation
Atasoy, Halil İbrahim; Demir, Şimşek; Department of Electrical and Electronics Engineering (2007)
This thesis presents the RF and mechanical design of a metal-to-metal contact RF MEMS switch. Metal-to-metal contact RF MEMS switches are especially preferred in low frequency bands where capacitive switches suffer from isolation due to the limited reactance. Frequency band of operation of the designed switch is from DC to beyond X-band. Measured insertion loss of the structure is less than 0.2 dB, return loss is better than 30 dB, and isolation is better than 20 dB up to 20 GHz. Isolation is greater than 2...
High performance readout and control electronics for mems gyroscopes
Şahin, Emre; Akın, Tayfun; Department of Electrical and Electronics Engineering (2009)
This thesis reports the development of various high performance readout and control electronics for implementing angular rate sensing systems using MEMS gyroscopes developed at METU. First, three systems with open loop sensing mechanisms are implemented, where each system has a different drive-mode automatic gain controlled (AGC) self-oscillation loop approach, including (i) square wave driving signal with DC off-set named as OLS_SquD, (ii) sinusoidal driving signal with DC off-set named as OLS_SineD, and i...
A new high voltage partial discharge indicator system
Gül, İbrahim Oğuz; Hızal, Mirzahan; Department of Electrical and Electronics Engineering (2006)
In this thesis work, a new partial discharge magnitude indicator with LCD display was designed. This system was implemented in high voltage partial discharge detection and measurement systems. AVRISP In-System programmer is used to program the microprocessors used inside the display unit. The time resolution of the system (one pixel of the display unit) is 4 microseconds. The unit is capable of counting the number of impulses of the input voltage that is coming from the high voltage system within user selec...
Dim target detection in infrared imagery
Çifçi, Barış; Atalay, Aydın; Department of Electrical and Electronics Engineering (2006)
This thesis examines the performance of some dim target detection algorithms in low-SNR imaging scenarios. In the past research, there have been numerous attempts for detection and tracking barely visible targets for military surveillance applications with infrared sensors. In this work, two of these algorithms are analyzed via extensive simulations. In one of these approaches, dynamic programming is exploited to coherently integrate the visible energy of dim targets over possible relative directions, where...
Optimum current injection strategy for magnetic resonance electrical impedance tomography
Altunel, Haluk; Eyüboğlu, Behçet Murat; Department of Electrical and Electronics Engineering (2008)
In this thesis, optimum current injection strategy for Magnetic Resonance Electrical Impedance Tomography (MREIT) is studied. Distinguishability measure based on magnetic flux density is defined for MREIT. Limit of distinguishability is analytically derived for an infinitely long cylinder with concentric and eccentric inhomogeneities. When distinguishability limits of MREIT and Electrical Impedance Tomography (EIT) are compared, it is found that MREIT is capable of detecting smaller perturbations than EIT. ...
Citation Formats
Y. Temiz, “Advanced readout and control electronics for mems gyroscopes,” M.S. - Master of Science, Middle East Technical University, 2007.