Electrical and Electronics Commons^™

8 Bit Split Array Based Charge Scaling Digital To Analog Converter With Rail To Rail Buffered Output, Sai Kiran Akula

Graduate Theses and Dissertations

This thesis presents the design, simulation and layout of a silicon carbide (SiC) 8 bit split array charge scaling digital to analog convertor (DAC). The converter consists of the charge scaling capacitor chain with two operational trans-conductance amplifiers (op amp) in voltage follower configuration. The op amps used in the design have the input common mode ranges of 0 to 11.2 V and 4.7V to 14.5V respectively. Additional logic circuit topologies are designed, which help to switch the op amps when needed to provide a rail to rail unity gain at the output. As the design is based on the …

High-Frequency Transformer Design For Solid-State Transformers In Electric Power Distribution Systems, Roderick Javier Garcia Montoya

Graduate Theses and Dissertations

The objective of this thesis is to present a high- or medium-frequency transformer design methodology for Solid-State Transformer (SST) applications. SSTs have been proposed as a replacement of the traditional 50/60 Hz transformer in applications demanding high-power density. Moreover, due to the high penetration of distributed generation, DC grids, energy storage systems, and sensitive loads, SSTs have been considered as an enabling technology for envisioned future energy systems. These applications demand additional functionalities that may not be achieved with traditional transformers. For example, active power flow control, harmonic suppression, voltage regulation, voltage sag compensation, and reduced size and volume.

In …

Design And Development Of A Wearable Wireless Health Monitoring System: A Smart Watch Approach, Keerthi Paranikumar

Graduate Theses and Dissertations

According to Statistics, every year, about 610,000 people die because of heart disease in United States of America. (i.e. 1 in every 4 deaths.*) Heart disease is common for both men and women. Annually, about 370,000 people die because of coronary heart disease, which is the most common type of heart disease [1]. About 735,000 Americans have heart attack every year. In this, 210,000 people gets heart attack who already has heart problems and 525,000 people get heart attack for the first time [2]. Not many people know that they have heart problems. Around 47% of the people in United …

Semi-Automated Switching Regulator Modeling Method And Tool, Michael Heath Leonard

Graduate Theses and Dissertations

This thesis presents the results of research targeted at automating the behavioral modeling process for switching voltage regulators. These regulators are commonly used in many application areas including discrete use in larger systems, integrated in a System on a Chip (SoC), or as the primary use case for a design. When used in an integrated system these regulators can be a significant force in slowing down simulations. A common method for removing this slowdown is to use a behavioral model of the switching regulator.

Creating behavioral models can be very time consuming and requires expertise.

The thesis discussion begins by …

Environmental Reliability Of Thin Film Sealing On Thick Film Ltcc, Charles R. Bourland

Graduate Theses and Dissertations

As electronic components and systems become more intricate and expand into new realms of use case scenarios, new materials systems must be explored. With new systems comes the balancing acts of cost and reliability. Presented here is a thesis that explores a new hybrid-electronics packaging system using low temperature co-fired ceramics, referred to as LTCC. An LTCC system was designed to explore the environmental reliability of numerous thick film LTCC features and parameters. A key element was to explore how a thin film metallization stack up used to cap or seal underlying thick film structures would decrease environmental susceptibility while …

The Role Of Quantum Dot Size On The Performance Of Intermediate Band Solar Cells, Najla Alnami

Graduate Theses and Dissertations

The goal of this thesis is to understand possible mechanisms for the reported decrease of the open circuit voltage and solar cell efficiency in quantum dot (QD) intermediate band solar cells (IBSCs). More specifically, the effect of indium arsenide (InAs) QD height on the open circuit voltage and solar cell efficiency was studied in a systematic way. To explore this effect in QD solar cells, several solar cells (SCs) were grown with varying InAs QD heights. All experimental characteristics of the QD solar cells were compared to a reference structure without QDs. All samples were grown by Molecular Beam Epitaxy …

Gesn Light-Emitting Devices, Yiyin Zhou

Graduate Theses and Dissertations

Silicon based optoelectronic devices have been investigated for decades. However, due to the indirect band gap nature of Si and Ge, developing of efficient light-emitting source on Si is still a challenging topic. GeSn based optoelectronic devices have the great potential to overcome this deficiency for several reasons. By adding more fraction of Sn into Ge, GeSn band gap could be reduced. The narrowed band gap could be developed for near to mid infrared applications. The alloy can even become the direct band gap material with a large Sn composition (beyond 8%). This feature could enhance the light emission from …

Metal Assisted Nanowire Growth For Silicon Nanowire/Amorphous Silicon Composite Solar Cell, Asmaa Ali Sadoon

Graduate Theses and Dissertations

Solar cells are photovoltaic devices that convert the energy of light to electricity by the photovoltaic effect. Crystalline silicon-based solar cells are the most dominant solar cells in the market today due to the high efficiency and relatively low cost. However, the cost of such solar cell is still high due to the large amount of material that is consumed in fabricating such a device. Polycrystalline/amorphous thin films and nanomaterial technologies have emerged to reduce the high cost of c-Si based solar cells and increase the efficiency. In this research, we combined these two technologies to propose and fabricate silicon …

Designing And Implementing A Micro-Controller Based Primary-Side Sensing Flyback Converter For Leds Driver, Nam Nhat Tran

Graduate Theses and Dissertations

The fast development of LED and its applications has enabled a new generation of lighting device with higher efficiency and long lifespan. By employing a primary-side sensing flyback converter and the PIC18F micro-controller series, an LED driver could achieve two important features: (1) the compatibility with the available lighting fixtures, and (2) reducing unit price. The flyback converter was chosen for its simplicity, competitive low cost, and its ability to provide a constant output current, a necessarily important factor to an LED driver. Meanwhile, the PIC18F micro-controller series offer numerous advanced features which include but not limited to pulse-width modulation …

Characterization And Model Verification Of Sic Cmos Transmisison Gates, Andrew H. Taylor

Electrical Engineering Undergraduate Honors Theses

The aim of this thesis is to present and explore the results of a method for characterizing CMOS transmission gates in an IC design process, as well as to describe their importance in circuit design. The method applies to any fabrication process, but the work for this thesis was conducted in a silicon-carbide process, in the first round of fabrication. The first section covers basic information regarding transmission gates, as well as showing their value in circuit design. Secondly, the design, simulation, and implementation of the characterizing test structures is detailed. The third section delineates the test setup and procedures …

Investigation Of The Effects Of Rapid Thermal Annealing On Mbe Grown Gaasbi/Gaas Heterostructures For Optoelectronic Devices, Perry C. Grant

Graduate Theses and Dissertations

High efficiency optoelectronic devices rely on high quality materials making up the device structure. The scope of this thesis investigates the effectiveness of rapid thermal annealing (RTA) at improving the material quality of GaAsBi/GaAs heterostructures. During the fabrication of a device, the contacts of the device had the rapid thermal annealing process accomplished to produce ohmic contacts and this research explored if this annealing treatment degraded the quantum wells that made up the active region of a device. To investigate these effects, a system to measure the photoluminescence of the material system was constructed utilizing Fourier Transform Infrared Spectroscopy. The …

Microfluidics Guided By Redox-Magnetohydrodynamics (Mhd) For Lab-On-A-Chip Applications, Vishal Sahore

Graduate Theses and Dissertations

Unique microfluidic control actuated by simply turning off and on microfabricated electrodes in a small-volume system was investigated for lab-on-a-chip applications. This was accomplished using a relatively new pumping technique of redox-magnetohydrodynamics (MHD), which as shown in this dissertation generated the important microfluidic features of flat flow profile and fluid circulation. MHD is driven by the body force, FB = j × B, which is the magnetic part of the Lorentz force equation, and its direction is given by the right hand rule. The ionic current density, j, was generated in an equimolar solution of potassium ferri/ferro cyanide by applying …

A Reconfigurable Digital-To-Analog Converter With Supply Invariant Linearity, Nicholas J. Chiolino

Graduate Theses and Dissertations

A novel reconfigurable digital-to-analog converter (DAC) with supply independent linearity is presented. The process agnostic converter achieves wide supply range operation and re-configurability by being charge based. This converter consists of a 7-bit parallel digital input control core and an analog "summing" core utilizing charging capacitors with an operational transconductance amplifier in a voltage-follower configuration. This topology is highly configurable to allow for optimization across process voltages, step sizes and low power operation. The specification of the DAC is (1) supply independence (2) low power operation (3) operation up to 200 kHz and (4) conversion control through a DAC enable …

A Wide Bandgap Silicon Carbide (Sic) Gate Driver For High Temperature, High Voltage, And High Frequency Applications, Ranjan Raj Lamichhane

Graduate Theses and Dissertations

The potential of silicon carbide (SiC) for modern power electronics applications is revolutionary because of its superior material properties including substantially better breakdown voltage, power density, device leakage, thermal conductivity, and switching speed. Integration of gate driver circuitry on the same chip, or in the same package, as the power device would significantly reduce the parasitic inductance, require far less thermal management paraphernalia, reduce cost and size of the system, and result in more efficient and reliable electrical and thermal performance of the system.

The design of a gate driver circuit with good performance parameters in this completely new under-development …

Design And Fabrication Of Inverter And Rectifier Modules For Indirect Matrix Converter Applications, Saikishore Talakokkula

Graduate Theses and Dissertations

In power converter applications, silicon carbide (SiC) power semiconductor devices are preferred over their silicon counterparts due to many advantages such as wide bandgap, high junction temperatures and low on-state resistance. The SiC devices provide reduced conduction and switching losses. Due to the above mentioned advantages the power conversion efficiency of SiC devices is better compared to that of silicon (Si) devices.

This thesis studies the implementation of 1200V/17A Normally-off SiC JFETs for an indirect matrix converter (IMC) application. A discussion on the parasitic inductance optimization is presented based on the electromagnetic simulation results extracted from the Ansoft Q3D extractor. …

High Voltage Direct Current Energy Transmission Using Modular Multilevel Converters, David Alejandro Guzman Pinzon

Graduate Theses and Dissertations

This thesis focus on high voltage direct current (HVdc) energy transmission using modular multilevel converter (MMC) based terminals. It provides a brief comparison between different HVdc technologies, focusing on voltage source converters (HVdc-VSC) with the MMC-based terminal emerging as the topology of choice for ratings less than 1 GW. The controllers for a two-terminal HVdc-link are analyzed and Matlab/Simulink^TM simulation models are presented. The simplified models and full Matlab/Simulink^TM based model are used to select the gains for the MMC controllers. Simulation results carried out on the full model validated the proposed methodologies. A new control technique that …

System Design And Motion Artifact Removal Algorithm Implementation For Ambulatory Women Ecg Measurement System:E-Bra System, Hyeokjun Kwon

Graduate Theses and Dissertations

Cardio Vascular Disease (CVD) leads to sudden cardiac death due to irregular phenomenon of the cardiac signal by the abnormal case of blood vessel and cardiac structure. For last three decades, there is an enhanced interest in research for cardiac diseases.. As a result, the death rate by cardiac disease in men has been falling gradually compared with relatively increasing the death rate for women due to CVD. The main reason for this phenomenon is due to the lack of seriousness to female CVD and different symptoms of female CVD compared with the symptoms of male CVD. Usually, because the …

Electrical Design Considerations And Packaging Of Power Electronic Modules, Shijie Wang

Graduate Theses and Dissertations

A modern power electronic module can save significant energy usage in the power electronic systems by improving their switching efficiencies. One way to improve the efficiency of the power electronic module is to reduce its parasitic circuit elements. The purpose of this thesis is to investigate the mitigation of parasitic circuit elements in power electronic modules. General methods of mitigating parasitic inductances were analyzed by the Q3D Extractor and verified by the time-domain reflectometry (TDR) measurements. In most cases, the TDR measurement results closely matched those predicted by the Q3D Extractor. These methods were applied to design and analyze a …

Spice Netlist Generation For Electrical Parasitic Modeling Of Multi-Chip Power Module Designs, Peter Tucker

Electrical Engineering Undergraduate Honors Theses

Multi-Chip Power Module (MCPM) designs are widely used in the area of power electronics to control multiple power semiconductor devices in a single package. The work described in this thesis is part of a larger ongoing project aimed at designing and implementing a computer aided drafting tool to assist in analysis and optimization of MCPM designs. This thesis work adds to the software tool the ability to export an electrical parasitic model of a power module layout into a SPICE format that can be run through an external SPICE circuit simulator. The code was implemented in python using NetworkX graphs …

Intermediate Band Solar Cells Based On Inas Quantum Dots Embedded In Ingaas Quantum Well, Ramesh Vasan

Graduate Theses and Dissertations

Intermediate band solar cells based on quantum dots and quantum wells with anti-reflection coating are investigated in this thesis. The demand for high efficient solar cells as an alternate source of energy is the main motivation for this research project. Intermediate band solar cells based on quantum dots were the subject of intensive research in recent years. High power conversion efficiency was predicted from InAs/GaAs intermediate band solar cells as the presence of InAs quantum dots increased the absorption below the band gap of the host material.

In this thesis, an attempt has been made to further increase the absorption …

Design And Implementation Of Wireless Point-Of-Care Health Monitoring Systems: Diagnosis For Sleep Disorders And Cardiovascular Diseases, Se Chang Oh

Graduate Theses and Dissertations

Chronic sleep disorders are present in 40 million people in the United States. More than 25 million people remain undiagnosed and untreated, which accounts for over $22 billion in unnecessary healthcare costs. In addition, another major chronic disease is the heart diseases which cause 23.8% of the deaths in the United States. Thus, there is a need for a low cost, reliable, and ubiquitous patient monitoring system. A remote point-of-care system can satisfy this need by providing real time monitoring of the patient's health condition at remote places. However, the currently available POC systems have some drawbacks; the fixed number …

Synthesis And Characterization Of Iron Pyrite Nanocrystals For Photovoltaic Devices, Scott Curtis Mangham

Graduate Theses and Dissertations

Iron pyrite nanocrystals have been synthesized using a hot-injection method with a variety of amines and characterized with properties necessary for photovoltaic devices. The iron pyrite nanocrystals were characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, optical absorption, micro-Raman, and micro-Photoluminescence. The optical absorbance spectra showed the large absorption in the visible and near infrared spectral range for the nanocrystals as well as to show the band gap. The face-centered cubic crystal structure of the iron pyrite nanocrystals was shown by matching the measured X-ray diffraction pattern to a face-centered cubic iron pyrite reference pattern. Using Bragg's law …

Synthesis Of Optimized Inp/Zns Core/Shell Nanocrystals And Tio2 Nanotubes For Quantum Dot Sensitized Solar Cells, Seungyong Lee

Graduate Theses and Dissertations

Synthesis of InP/ZnS core/shell nanocrystals and TiO₂ nanotubes and the optimization study to couple them together were explored for quantum dot sensitized solar cells. Its intrinsic nontoxicity makes the direct band gap InP/ZnS core/shell be one of the most promising semiconductor nanocrystals for optoelectric applications, with the advantage of tuning the optical absorption range in the desired solar spectrum region. Highly luminescent and monodisperse InP/ZnS nanocrystals were synthesized in a non-coordinating solvent. By varying the synthesis scheme, different size InP/ZnS nanocrystals with emission peaks ranging from 520 nm to 620 nm were grown. For the purpose of ensuring air …

Computational Design Of The Electrical And Mechanical Performance Of Steerable Mems Antennas, Morgan Andrew Roddy

Graduate Theses and Dissertations

This thesis describes the origins, improvements, and variations of a broadband microwave antenna that can be beam-steered by a micro-electromechanical system (MEMS). The steerable MEMS antenna of this work was comprised of a planar antenna on top of a Silicon membrane. The membrane is etched to create a gimbal hinge structure and a platform which supported the antenna and gave it one or two degrees of freedom of rotation. The antennas presented were broadband and fed by a coplanar waveguide (CPW) transmission line which traversed the hinge structure. The antenna's orientation in space was designed to be changed through electrostatic …

Design And Analysis Of An Adaptive Asynchronous System Architecture For Energy Efficiency, Brent Michael Hollosi

Graduate Theses and Dissertations

Power has become a critical design parameter for digital CMOS integrated circuits. With performance still garnering much concern, a central idea has emerged: minimizing power consumption while maintaining performance. The use of dynamic voltage scaling (DVS) with parallelism has shown to be an effective way of saving power while maintaining performance. However, the potency of DVS and parallelism in traditional, clocked synchronous systems is limited because of the strict timing requirements such systems must comply with. Delay-insensitive (DI) asynchronous systems have the potential to benefit more from these techniques due to their flexible timing requirements and high modularity. This dissertation …

Thermal And Electrical Parasitic Modeling For Multi-Chip Power Module Layout Synthesis, Zihao Gong

Graduate Theses and Dissertations

This thesis presents thermal and electrical parasitic modeling approaches for layout synthesis of Multi-Chip Power Modules (MCPMs). MCPMs integrate power semiconductor devices and drive electronics into a single package. As the switching frequency of power devices increases, the size of the passive components are greatly reduced leading to gains in efficiency and cost reduction. In order to increase switching frequency, electrical parasitics in MCPMs need to be reduced through tighter electronic integrations and smaller packages. As package size is decreased, temperature increases due to less heat dissipation capability. Thus, it is crucial to consider both thermal and electrical parasitics in …

Study Of Current Optocoupler Techniques And Applications For Isolation Of Sensing And Control Signals In Dc-Dc Converters, Jake Williams

Graduate Theses and Dissertations

There is a need for power switches that can operate at high voltage, high temperature, and high switching frequencies with low losses. Power switches fabricated from wide bandgap materials such as silicon carbide (SiC) or gallium nitride (GaN) can outperform conventional silicon switches due to material property advantages. Another common problem in grid-connected applications is the need for high voltage-isolation of gate drivers and control circuitry while operating efficiently at the high switching frequencies, high power density, and high temperatures made possible by wide bandgap devices. Transformers cannot operate at the temperatures of these wide bandgap devices and a new …

Ultra-Low Voltage Digital Circuits And Extreme Temperature Electronics Design, Aaron J. Arthurs

Graduate Theses and Dissertations

Certain applications require digital electronics to operate under extreme conditions e.g., large swings in ambient temperature, very low supply voltage, high radiation. Such applications include sensor networks, wearable electronics, unmanned aerial vehicles, spacecraft, and energyharvesting systems. This dissertation splits into two projects that study digital electronics supplied by ultra-low voltages and build an electronic system for extreme temperatures. The first project introduces techniques that improve circuit reliability at deep subthreshold voltages as well as determine the minimum required supply voltage. These techniques address digital electronic design at several levels: the physical process, gate design, and system architecture. This dissertation analyzes …

Delay Insensitive Ternary Logic Utilizing Cmos And Cntfet, Ravi Sankar Parameswaran Nair

Graduate Theses and Dissertations

As digital circuit design continues to evolve due to progress of semiconductor processes well into the sub 100nm range, clocked architectures face limitations in a number of cases where clockless asynchronous architectures require substantially less power, generate less noise, and produce less electromagnetic interference (EMI). This dissertation develops the Delay Insensitive Ternary Logic (DITL) asynchronous design paradigm that combines the designs aspects of similar Dual-Rail asynchronous paradigms and Boolean logic to create a single wire per bit, three voltage signaling and logic scheme.

DITL is designed at the transistor level using multi-threshold CMOS and carbon nanotube (CNT) FETs to develop …

Design Of A High Dynamic Range Cmos Variable Gain Amplifier For Wireless Sensor Networks, Yue Yu

Graduate Theses and Dissertations

This thesis presents the design, simulation, layout and testing results for a dB-linear, high dynamic gain range CMOS variable gain amplifier (VGA). The design adopts a new approximated exponential equation called the pseudo exponential equation to implement the dB-linear function. The proposed VGA is designed to have an extremely wide gain variation, small chip area, low supply voltage, and controllable dynamic gain range. The gain variation of the 3-stage VGA is implemented by a voltage to current converter. It controls the bias currents of each VGA cell, so that the output gain of each cell can be controlled. In order …