Electronic Devices and Semiconductor Manufacturing Commons^™

Energy Harvesting From Exercise Machines: Lt8705 Dc-Dc Conversion For Elliptical Trainers, Braden Burk, Raj Bhula, Nathan Mckay

Electrical Engineering

Cal Poly’s Energy Harvesting from Exercise Machines (EHFEM) program aims to power the grid using human energy harvested from exercise machines in its gym. Doing so could save the school money and increase the total supply of power available on the grid. This document belongs to one of many groups attempting to design a suitable DC-DC conversion system for an elliptical trainer using an LT8705 Four-Switch Buck-Boost converter. Past teams have built other converters and developed system compatibility characteristics such as filtering, safety, and stability for interfacing components. These teams fall into one of two departments in EHFEM: DC-DC Conversion …

Buck Converter, Bowen Liu

Electrical Engineering

The recent sustainable energy growth triggered a huge power electronics demand, specifically related to power conversion. My senior project is a design of a buck converter which steps down the voltage from photovoltaic cells ranging from 5 to 40V to a rechargeable battery with 5V. This converter has a high enough power efficiency to effectively convert the energy harnessed from PV panels.

Lna Integrates Fast Shutdown Function, Chin-Leong Lim

Chin-Leong Lim

To minimize dead time in time domain duplex (TDD) transceiver, reception should ideally commence as soon as transmission ends. However, the low noise amplifier (LNA), which is typically shutdown during transmission to prevent device damage and receiver overload, can exhibit a turn-on delay. In older implementations, the shutdown function is external to the LNA device. So, one way to reduce part count and to miniaturize this class of LNA is to integrate the LNA and shutdown function in a microwave monolithic integrated circuit (MMIC). The integration also allows the shutdown circuit to be connected to the LNA at an optimum …

A Fast-Converging Mppt Technique For Photovoltaic System Under Fast Varying Solar Irradiation And Load Resistance, Saad Mekhilef

Saad Mekhilef

Under fast varying solar irradiation and load resistance, a fast-converging maximum power point tracking system is required to ensure the photovoltaic system response rapidly with minimum power losses. Traditionally, maximum power point locus was used to provide such a fast response. However, the algorithm requires extra control loop or intermittent disconnection of the PV module. Hence, this paper proposes a simpler fast-converging maximum power point tracking technique, which excludes the extra control loop and intermittent disconnection. In the proposed algorithm, the relationship between the load line and the I–V curve is used with trigonometry rule to obtain the fast response. …

Hybrid Silicon Mode-Locked Laser With Improved Rf Power By Impedance Matching, Bassem M. Tossoun

Master's Theses

The mode-locked laser diode (MLLD) finds a lot of use in applications such as ultra high-speed data processing and sampling, large-capacity optical fiber communications based on optical time-division multiplexing (OTDM) systems. Integrating mode-locked lasers on silicon makes way for highly integrated silicon based photonic communication devices. The mode-locked laser being used in this thesis was built with Hybrid Silicon technology. This technology, developed by UC Santa Barbara in 2006, introduced the idea of wafer bonding a crystalline III- V layer to a Silicon-on-insulator (SOI) substrate, making integrated lasers in silicon chips possible.

Furthermore, all mode-locked lasers produce phase noise, which …

Design And Evaluation Of An L-Band Current-Mode Class-D Power Amplifier Integrated Circuit, Michael J. Shusta

Masters Theses

Power amplifiers (PAs) convert energy from DC to high frequencies in all radio and microwave transmitter systems be they wireless base stations, handsets, radars, heaters, and so on. PAs are the dominant consumers of energy in these systems and, therefore, the dominant sources of system cost and inefficiency. Research has focused on efficient solid-state PA circuit topologies and their optimization since the 1960s. The 2000s saw the current-mode class-D (CMCD) topology, potentially suitable for today's wireless communications systems, show promise in the UHF frequency band. This thesis describes the design and testing of a high-efficiency CMCD amplifier with an integrated …

In-Line Microfluidic Particle Preconcentrator And Detector For Continuous Flow Monitoring, Quan Yuan

Doctoral Dissertations

This dissertation presents the design and prototyping of three in-line microfluidic devices for continuous monitoring of particulate flows. The three devices are AC electrokinetic (ACEK) and acoustic sample preconcentration techniques for resettable particle enrichment, and an in-line somatic cell counter for mastitis monitoring.

For the ACEK preconcentrator, ACEK is a new and promising technique to manipulate micro/bio-fluid and particles. There are many advantages over other techniques, such as low applied voltage, low cost, portability and notable biocompatibility of lab-on-a-chip (LOC) device. We successfully developed a 3D multi-level electrode platform to extract bioparticles via AC electroosmosis (ACEO) and negative Dielectrophoresis (DEP). …

Low Loss Configuration For Integrated Pin-Schottky Limiters, Chin-Leong Lim

Chin-Leong Lim

Compared to the PIN diode limiter, the Schottky-PIN limiter improves receiver protection, but has a higher insertion loss. Low cost, plastic packaged diodes can further worsen the loss. Diode stacking, mesa diode construction, and isolating the Schottky diode with a high-impedance quarter wave line or a directional coupler can reduce loss, but detrimentally raises the limiting threshold and/or adds bulk or cost. The PIN-Schottky limiter’s insertion loss can be improved by integrating the diodes’ parasitic capacitances into a low pass ladder network, but this solution requires the PIN diode to have two anode connections. Recently, the PIN-Schottky limiter was integrated …

Novel Configuration For Multilevel Dc-Link Three-Phase Five-Level Inverter, Saad Mekhilef

Saad Mekhilef

new multilevel DC-link three-phase five-level voltage source inverter topology is introduced here. A multilevel DClink formed from single DC voltage supply and two cascaded half-bridge (CHB) power cells is connected to 12-switch threephase bridge in such a way that the proposed inverter produces five levels in the output voltage waveform. Compared to comparable inverters, such as symmetrical CHB and hybrid multilevel inverters, the proposed topology maximises the number of voltage levels and reduces the number of utilised DC voltage supplies, switches, gate driver circuits and installation area. A modified fundamental frequency modulation technique based on determination of switching states of …

Ultraviolet Led Biofouling Mitigation, Andrew Lam

Computer Engineering

The goal is to determine if low-cost UV LEDs can mitigate marine biofouling on small glass or acrylic camera lenses. A microprocessor-controlled experimental setup to control the illumination of low-cost UV LEDs of various wavelength and packaging was fashioned. The system consists of a programmed microcontroller, a manufactured LED breakout interface, and a submergible UV LED array enclosed in a borosilicate glass tube. A preliminary qualitative assessment of four different UV LEDs was conducted during a three-week deployment of the experimental setup in the raw seawater system at the Cal Poly Center for Costal and Marine Sciences in Avila Beach, …

Rapid Battery Exchange Safety And Sensing, Ben John Froelich, Isaac Sungjin Kim

Electrical Engineering

The Rapid Battery Exchange system (RBX) swaps batteries in an electric van, allowing almost continuous operation of the vehicle. The RBX system is designed and built by The Cal Poly Electric Vehicle Engineering Club (EVEC). The system includes the exchange ramp, two battery packs, and the electric “G-Van.” While the vehicle drives using one of the battery packs, the other pack charges in the exchange ramp. When the van’s battery depletes, it drives onto the ramp and swaps the dead battery for the charged one, and the process repeats.

The RBX battery pack safety and sensing project divides into two …

Mos Current Mode Logic (Mcml) Analysis For Quiet Digital Circuitry And Creation Of A Standard Cell Library For Reducing The Development Time Of Mixed Signal Chips, David Marusiak

Master's Theses

Many modern digital systems use forms of CMOS logical implementation due to the straight forward design nature of CMOS logic and minimal device area since CMOS uses fewer transistors than other logic families. To achieve high-performance requirements in mixed-signal chip development and quiet, noiseless circuitry, this thesis provides an alternative toCMOSin the form of MOS Current Mode Logic (MCML). MCML dissipates constant current and does not produce noise during value changing in a circuit CMOS circuits do. CMOS logical networks switch during clock ticks and with every device switching, noise is created on the supply and ground to deal with …

Low Voltage Cmos Sar Adc Design, Ryan Hunt

Electrical Engineering

This project centers on the design of a single ended 10-bit successive approximation register analog to digital converter (SAR ADC for short) that easily interfaces to a micro-controller, such as an Arduino. With micro-controller interfacing in mind, the universal data transfer technique of SPI proved an easy way to communicate between the ADC and the micro-controller. The ADC has a range of 1V (highest code value) to 0V (lowest code value) and operates from a single voltage rail value of 1.8V. Typical SPI clock speeds run on the order of 2MHz and with a 10-bit ADC this means a sampling …

Investigation Of Degradation Effects Due To Gate Stress In Gan-On-Si High Electron Mobility Transistors Through Analysis Of Low Frequency Noise, Michael Curtis Meyer Masuda

Master's Theses

Gallium Nitride (GaN) high electron mobility transistors (HEMT) have superior performance characteristics compared to Silicon (Si) and Gallium Arsenide (GaAs) based transistors. GaN is a wide bandgap semiconductor which allows it to operate at higher breakdown voltages and power. Unlike traditional semiconductor devices, the GaN HEMT channel region is undoped and relies on the piezoelectric effect created at the GaN and Aluminum Gallium Nitride (AlGaN) heterojunction to create a conduction channel in the form of a quantum well known as the two dimensional electron gas (2DEG). Because the GaN HEMTs are undoped, these devices have higher electron mobility crucial for …

Modified Incremental Conductance Algorithm For Photovoltaic System Under Partial Shading Conditions And Load Variation, Saad Mekhilef

Saad Mekhilef

Under partial shading conditions, multiple peaks are observed in the power–voltage (P–V ) characteristic curve of a photovoltaic (PV) array, and the conventional maximum power point tracking (MPPT) algorithms may fail to track the global maximum power point (GMPP). Therefore, this paper proposes a modified incremental conductance (Inc Cond) algorithm that is able to track the GMPP under partial shading conditions and load variation. A novel algorithm is introduced to modulate the duty cycle of the dc–dc converter in order to ensure fast MPPT process. Simulation and hardware implementation are carried out to evaluate the effectiveness of the proposed algorithm …

Long-Term Wind Speed Forecasting And General Pattern Recognition Using Neural Networks, Saad Mekhilef

Saad Mekhilef

Long-term forecasting of wind speed has become a research hot spot in many different areas such as restructured electricity markets, energy management, and wind farm optimal design. However, wind energy with unstable and intermittent characteristics entails establishing accurate predicted data to avoid inefficient and less reliable results. The proposed study in this paper may provide a solution regarding the long-term wind speed forecast in order to solve the earlier-mentioned problems. For this purpose, two fundamentally different approaches, the statistical and the neural network-based approaches, have been developed to predict hourly wind speed data of the subsequent year. The novelty of …

Bi-Directional Vector Variable Gain Amplifier For An X-Band Phased Array Radar Application, Arash Mashayekhi

Masters Theses 1911 - February 2014

This thesis presents the design, layout, and measurements of a bi-directional amplifier with variable vector (in-phase / quadrature) gain control that will be part of an electronically steered phased array system. The electronically steered phased array has many advantages over the conventional mechanically steered antennas including rapid scanning of the beam and adaptively creating nulls in desired locations. The 10-bit bi-directional Vector Variable Gain Amplifier (VVGA) is part of the transmit and receive module of each antenna element where transmit and receive functionality is determined through a simple switch. The VVGA performs amplification of the IF IQ pair by an …

Electron – Phonon Interaction In Multiple Channel Gan Based Hfets: Heat Management Optimization, Romualdo A. Ferreyra

Theses and Dissertations

New power applications for managing increasingly higher power levels require that more heat be removed from the power transistor channel. Conventional treatments for heat dissipation do not take into account the conversion of excess electron energy into longitudinal optical (LO) phonons, whose associated heat is stored in the channel unless such LO phonons decay into longitudinal acoustic (LA) phonons via a Ridley path. A two dimensional electron gas (2DEG) density of ~5×10¹²cm^-2 in the channel results in a strong plasmon–LO phonon coupling (resonance) and a minimum LO phonon lifetime is experimentally observed, implying fast heat removal from …

Quantum Efficiency Enhancement For Gan Based Light-Emitting Diodes And Vertical Cavity Surface-Emitting Lasers, Fan Zhang

Theses and Dissertations

This thesis explores the improvement of quantum efficiencies for InGaN/GaN heterostructures and their applications in light-emitting diodes (LEDs) and vertical cavity surface-emitting lasers (VCSELs). Different growth approaches and structural designs were investigated to identify and address the major factors limiting the efficiency. (1) Hot electron overflow and asymmetrical electron/hole injection were found to be the dominant reasons for efficiency degradation in nitride LEDs at high injection; (2) delta p-doped InGaN quantum barriers were employed to improve hole concentration inside the active region and therefore improve hole injection without sacrificing the layer quality; (3) InGaN active regions based on InGaN multiple …

Measurement And Modeling Of Humidity Sensors, Jingbo Tong

Theses and Dissertations--Electrical and Computer Engineering

Humidity measurement has been increasingly important in many industries and process control applications. This thesis research focus mainly on humidity sensor calibration and characterization. The humidity sensor instrumentation is briefly described. The testing infrastructure was designed for sensor data acquisition, in order to compensate the humidity sensor’s temperature coefficient, temperature chambers using Peltier elements are used to achieve easy-controllable stable temperatures. The sensor characterization falls into a multivariate interpolation problem. Neuron networks is tried for non-linear data fitting, but in the circumstance of limited training data, an innovative algorithm was developed to utilize shape preserving polynomials in multiple planes in …