Browsing by Subject "Switching circuits"
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Item An efficient algorithm for switchbox routing(Texas Tech University, 1983-08) Tsay, Ching-yuhNot availableItem Current-mode analog-to-digital conversion techniques(Texas Tech University, 1993-05) Wong, Kwok ChungThe aim of the research is to develop an A/D converter which is suitable for applications in telecommunication and instrumentation areas and is compatible with the present day CMOS digital process. Viewing the potential advantages offered by current-mode techniques, it is decided to utilize these techniques to realize the converter. In the course of the research, different structures of A/D converters have been developed to enhance the A/D performance.Item Design and construction of a diffuse discharge experiment(Texas Tech University, 1983-05) Hutcheson, George ZohnA definition and characterization of diffuse discharees is presented, and the conditions necessary for the production of diffuse discharges are discussed. The design and construction of an experimental device that produces diffuse discharges for the study of optically controlled diffuse discharge opening switches is described. It is shown that these control processes require diffuse discharges as a switch medium. Diagnostic voltage and current probes were built into the system and were found to have rise-times of less than 5 ns. The device constructed produces discharges in Helium at gas pressures up to 200 torr.Item Design and construction of a high power electron gun(Texas Tech University, 1984-05) Leiker, Gary RA high power electron gun capable of producing an e-beam over a 100 square centimeter area has been designed and tested. Grid control of the e-beam provides 100 ns, 250 keV electron bursts through the foil in 100 ns intervals. Results of voltage and current measurements of the electron beam, as well as measurements of its spatial and temporal uniformity, are presented.Item Developing an all optical switch using digital micromirror device (DMD) array for wavelength division multiplexing (WDM) applications(Texas Tech University, 2002-05) Sundaram, SriramA relational non-interferometric polarization-insensitive space division 1 x 4 all optical switch based on the digital mirror array device is described and analyzed. An insertion loss of -5.5dBm, crosstalk less than -37.1 dBm and bit-error-rates of less than 10"^ have been measured at 2.5Gb/s. The performance of the switch in multiwavelength applications to variable optical attenuator, multicasting and dynamic gain equalization is described. The fast switching speed of -15 |is of the digital micromirrors provides dynamic switching in all the before mentioned applications, ensuring optimum network performance at all times.Item Development of a second breakdown model for bipolar transistors(Texas Tech University, 1988-12) Menhart, SteveSemiconductor devices are often driven Into operating regions in which conventional models, representing normal regions of operation, are Inadequate. An example of such an operating region is frequently obtained when bipolar transistors are operated as switches in circuits containing inductors. In this case, the transistor may experience large voltages and currents simultaneously. In an actual transistor, the collector-emitter voltage is constrained by avalanche breakdown between the collector and emitter regions; under conditions of breakdown or near-breakdown and high collector current, an instability, known as second breakdown, may occur. This instability often results in catastrophic device failure. The library bipolar transistor model contained within the circuit analysis code, SPICE, is quite sophisticated, within a normal region of transistor operation. However, it does not model either avalanche or second breakdown. Several models, in the form of augmentations to the SPICE transistor model, have been developed in this work- These models permit SPICE to predict accurately voltages and currents associated with the transient response of circuits containing both energy storage elements and active devices, which the standard SPICE code alone is incapable of doing. In this work avalanche breakdown has been modeled in a manner not previously encountered by the author. This model recognizes the interdependence of the two transistor Junctions, with regard to breakdown between the collector and emitter regions. A second breakdown model that previously did not exist, is presented. The concept of a dependent subcircuit is introduced to model second breakdown, in which case the subcircuit also performs diagnostic and controlling functions, as an integral part of the model. A subcircuit such as used in this work to model second breakdown is analogous to an analog computer.Item Efficient algorithms for channel routing in circuit layout(Texas Tech University, 1983-08) Boar, Show-yuiNot availableItem Fast transient switching in bipolar junction transistors and metal-oxide-semiconductor field effect transistors(Texas Tech University, 1985-12) Menhart, SteveNot availableItem Integrated circuit design of a sequential state machine(Texas Tech University, 1996-12) Venkataraman, Kamala NNot availableItem Investigation of ultra-high switching frequency to reduce size in rapid capacitor charging(Texas Tech University, 2004-05) Morris, BenThis project concerned itself with two different chargers, both based on the same principle designs but both having fundamentally different output and input requirements and goals. Both chargers were built using a full bridge setup that was MOSFET based utilizing frequencies of 187 kHz to 1 MHz being examined. The modulated DC voltage is applied to a transformer and then a multiplier cascade is used to complete the final voltage increases. The 40kV charger had a requirement of 100-300VDC input with a 40kV, 40kW, IkJ output requirement in 10ms or less. The 50kV charger required a higher output voltage with a considerably lower input voltage requirement of 40-50VDC and was required to operate repetitively at 200Hz. Transformer, voltage multiplier, circuit board layouts, and battery system designs and tests are all covered.Item Nonlinear magnetic switches for pulse generation(Texas Tech University, 1980-05) Black, Susan ENot availableItem Reverse bias second breakdown in power switching transistors(Texas Tech University, 1982-12) Skelton, Dale JamesNot availableItem Switching output stages for direct PCM-PWM amplification with enhanced PSRR and THD performance(Texas Tech University, 2003-12) Pate, Michael ScotThis thesis describes the process involved in designing the loop filter that is required when changing a class-D power output stage from a full-bridge configuration to a half-bridge. The loop filter designed is part of an error correction feedback network. This thesis covers the basic theoretical derivations for the device, complete circuit design and simulation and basic device layout considerations. Ideas for future versions are given for reference.