A Low-power capacitive integrated CMOS readout circuitry for high performance MEMS accelerometers

Download
2013
İncedere, Osman Samet
This thesis presents a low power capacitive integrated CMOS readout circuitry for high performance MEMS accelerometers. It proposes a linearized model of the complete closed loop accelerometer system, which makes easier of designing and analyzing the system. Designed readout circuitry offers low noise, wide dynamic range and high linearity system with very low power consumption. Designed readout circuit includes proportional integral (PI) controller circuit, which significantly decreases the proof mass deflection of the accelerometer resulting in high linearity and high immunity to sensor parameter changes. Designed system also suppresses the readout circuit noise in a significant amount and this noise suppression allows designing very low power readout circuits without degrading the noise performance of the system. Readout circuit provides highly programmable digital controller circuit, which allows controlling of all digital timing signals, bias currents and voltages, and power consumptions of analog blocks, front-end circuit gain, gain coefficients of PI controller and sigma-delta modulator gain. Designed readout circuit also offers optional external timing signals and optional external voltage reference. The readout circuit is implemented using 0.35 um process. Circuit level and system level simulations are performed in Cadence and MATLAB Simulink environments respectively. The simulations guarantee stability and proper operation of the accelerometer system. As a sensing element, accelerometer having the ! v! specifications of 3.5x10-6 F/m sensitivity, 9.5 pF rest capacitance, 2.32 kHz resonant frequency and 4.6 μg/√Hz Brownian noise, is used. Simulation results show that system has 5.3 μg/√Hz noise level at the output, ± 19.5 g full scale range, 128.5 dB dynamic range and 1.8 mW power consumption with 3.3 V supply voltage.

Suggestions

Low-cost microbolometer infrared detectors utilizing CMOS resistive layers
Öztürk, Hande; Akın, Tayfun; Department of Electrical and Electronics Engineering (2017)
This thesis presents the efforts to develop low-cost microbolometer type uncooled infrared detector architectures that utilize standard CMOS layers and components. Various resistance structures of different CMOS technologies are investigated and possible resistors are determined as the active material. In order to figure out potential microbolometer structure, all possible layers in the CMOS technologies are analyzed in terms of mechanical and thermal parameters. Mathematical modeling and computer simulatio...
A CMOS switched-capacitor interface circuit for an integrated accelerometer
Külah, Haluk; Najafi, K (2000-01-01)
This paper presents a CMOS interface electronics for monolithic micromachined capacitive accelerometer systems. The interface electronics is a fully differential switched-capacitor charge integrator with its internal clock generator and sensor feedback circuit for closed-loop operation. The circuit is designed for open-loop and closed-loop operations, and provides both digital and differential analog outputs. One of the main advantages of this chip is that it can be monolithically integrated with the sensor...
A Low-power memory CMOS integrated circuit for image sensors
Üstündağ, Mithat Cem Boreyda; Akın, Tayfun; Department of Electrical and Electronics Engineering (2015)
This thesis presents a low power SRAM block implemented in a 0.35 μm CMOS technology for imaging applications to be used inside a digital image processor ASIC (Application Specific Integrated Circuit). The SRAM structure is designed to be fast enough to store all the image data fed by a large format readout circuitry such as VGA (640x512), while requiring low power consumption. The low power consumption is a very critical requirement of such circuit, as the circuit will eventually be used in an embedded pla...
A Capacitive MEMS Accelerometer Readout with Concurrent Detection and Feedback Using Discrete Components
Terzioglu, Yunus; Alper, Said Emre; Azgın, Kıvanç; Akın, Tayfun (2014-05-08)
This paper presents an analog readout method for capacitive MEMS accelerometers in which the feedback actuation and capacitive detection are achieved simultaneously on the same electrode set. The presented circuit operates in closed-loop for improved linearity, and it is constructed in a hybrid platform package in which off-the-shelf discrete components are used together with the silicon-on-glass micro-accelerometer. The system is developed as a practical solution to reduce the complexity of the readout cir...
CMOS readout electronics for mis-matched and mode-matched MEMS gyroscopes
Yeşil, Ferhat; Akın, Tayfun; Department of Electrical and Electronics Engineering (2015)
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-ma...
Citation Formats
O. S. İncedere, “A Low-power capacitive integrated CMOS readout circuitry for high performance MEMS accelerometers,” M.S. - Master of Science, Middle East Technical University, 2013.