Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 33 for “"op-amp"”.
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A precision CMOS continuous-time autozeroed op-amp
Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2001.
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Operational Amplifier Bandwidth Extension Using Negative Capacitance Generation
A need for high bandwidth operational amplifiers, or op-amps, exists for certain applications. This need requires research in the area of op-amp bandwidth extension. The proposed method of this thesis uses Negative Capacitance Generation (NCG), which involves using the Miller effect to generate an …
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High Gain Low Power Operational Amplifier Design and Compensation Techniques
… compares the existing compensation methods for operational amplifiers. It explores a method to stabilize the op amps without sacrificing bandwidth to the same degree that commonly used methods do. A creative design methodology combining intuition, mathematical analysis, and mixed level …
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A pipelined analog-to-digital converter with low-gain, low-bandwidth op-amps
Designing a high-gain, high-bandwidth op-amp for pipelined ADCs in fine-line CMOS technology has become increasingly challenging. In order to address this issue, this thesis presents the shadow-ADC-assisted digital calibration technique. The proposed technique relaxes op-amp performance …
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Virtual ground reference buffer technique in switched-capacitor circuits
… circuits depends highly on the op-amp specifications. In conventional designs, trade-offs in speed, noise, and settling accuracy make it difficult to implement power-efficient switched-capacitor circuits. The problem originates from the inverse relationship between the feedback …
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The role of organophosphate exposure in the aetiology of depression and suicidality amoungst farm workers on wine and table grape farms in the Worcester area of the Western Cape Province, South Africa
… Safety Act (Act 85 of 1993, Section 8(1)) that âevery employer shall provide and maintain a working environment that is safe and without risk to the health of its employeesâ, farm workers in South Africa are exposed to numerous occupational health and safety hazards on a …
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A Comparator-Based Switched-Capacitor delta sigma modulator
… Switched-Capacitor (CBSC) is a relatively new topology that replaces op-amps in sampled-data systems with a comparator and a set of current mirrors. CBSC is expected to lower power consumption, and to avoid several delicate tradeoffs of op-amp circuits. In this paper, the original single-ended …
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High performance zero-crossing based pipelined analog-to-digtal converters
… More specifically, the design of a high gain op-amp, a fundamental analog building block, has become more difficult in scaled processes. In this work, op-amps in pipelined ADCs are replaced with zero-crossing detectors(ZCD). Without the closed-loop feedback provided by the op-amp, a new set of …
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Two-Stage Operational Amplifier Design by Using Direct and Indirect Feedback Compensations
… paper states the stability requirements of the amplifier system, and then presents, and summarizes, the classic two stage CMOS Op-Amp design by employing several popular frequency compensation techniques including traditional Miller compensation, nulling resistor, voltage buffer, and current …
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Design of a continuous-time bandpass delta-sigma modulator
… noise ratio (SNR) of 75.5 dB. The modulator samples at 1 GS/s while consuming 319 mW. On the system level, the feedback topology secures stability for the 8th-order system, achieving a maximum stable input range of -1.9 dBFS. A 2.5-V/1.2-V dual-supply loop filter with a feed-forward coupling …
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A low power digitizer for precision carrier band measurements
It has been found that the amplitude of the 20kHz harmonic at the output of a particular third order [Sigma][Delta] analog to digital converter drifts significantly as the temperature fluctuates. In this document, both methods of ascertaining the source of this drift and ways to reduce it are …
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Design and Assembly of High-Temperature Signal Conditioning System on LTCC with Silicon Carbide CMOS Circuits
… described in this dissertation paper is to develop a prototype electronic module on a low-temperature co-fired ceramic (LTCC) material. The electronic module would perform signal conditioning of sensor signals (thermocouples) operating under extreme conditions for applications like gas turbines …
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A time-interleaved Zero-Crossing-Based analog-to-digital converter
… difficult to realize high-speed, high-gain op-amps with a stable feedback loop. The switched capacitor multiplier circuit in pipelined ADC is one application which has been hindered by op-amp limitations. Zero Crossing Based (ZCB) switched-capacitor topologies have been proposed as an …
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Out-of-Loop Compensation Method for Op-Amps Driving Heavy Capacitive Loads
<p>It is well known that real op-amps do not share most of the desirable characteristics of an ideal one, particularly those of gain and output impedance. When presented with a capacitive load, such as a MOSFET or ADC, feedback in an op-amp circuit can quickly become unstable. This thesis studies …
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Time-based circuits for communication systems in advanced CMOS technology
… (ring VCO) as a continuous-time integrator. We propose to replace conventional integrators designed with analog circuits in a [sigma][delta] modulator with a ring VCO and a phase detector, thereby implementing an A/D converter without traditional analog circuits. We also propose a single-slope A/D …
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A zero-crossing switched-capacitor filter design
… were suggested as a possible solution to the op-amp based circuits. In this thesis, we explore zero-crossing based circuits (ZCBC) in high-order differential switched-capacitor filters to replace area inefficient op-amps-based continuous-time baseband filters. For the prototype for the …
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A comparator-based switched-capacitor pipelined analog-to-digital converter
… switched-capacitor(CBSC) technique is proposed that eliminates the need for high gain op-amps in switched-capacitor circuits. The CBSC technique replaces the op-amp in switched-capacitor circuits with a comparator and a current source. Compared to op-amps, comparators suffer less from the …
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Noise analysis of switched capacitor filters
… in SC filters are switch transistors and the operational amplifiers. These noise sources were modeled as switch thermal white noise and op-amp input white noise. The existence of direct and sample-and-held noise outputs were demonstrated. The direct noise, resulting from direct circuit path, …
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Battery Cell Monitoring Unit
The proposed cell monitoring unit for sensing voltage, current, and temperature in a 12-cell 18650 lithium-ion battery module aims to be low-power, serving as the core of an energy-efficient battery management system and facilitating battery management functions with cell data. Notable features …
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Simultaneous Energy Harvesting and Vibration Control via Piezoelectric Materials
… performance of small UAVs in wind gusts. The proposed multifunctional wing spar integrates a flexible solar cell array, flexible piezoelectric wafers, a thin film battery and an electronic module into a composite sandwich structure. The basic design factors are discussed for a beam-like …
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