1,091 research outputs found
CMOS analog-digital circuit components for low power applications
Dissertação de mestrado em Micro and NanoelectronicsThis dissertation presents a study in the area of mixed analog/digital CMOS power extraction
circuits for energy harvester.
The main contribution of this work is the realization of low power consumption and
high efficient circuit components employable in a management circuit for piezoelectricbased
energy harvester. This thesis focuses on the development of current references and
operational amplifiers addressing low power demands. A brief literature review is conducted
on the components necessary for the power extraction circuit, including introduction to
CMOS technology design and research of known low power circuits. It is presented with
multiple implementations for voltage and current references, as well for operational amplifier
designs.
A self-biased current reference, capable of driving the remaining harvesting circuit, is
designed and verified. A novel operational amplifier is proposed by the use of a minimum
current selector circuit topology. It is a three-stage amplifier with an AB class output stage,
comprised by a translinear circuit. The circuit is designed, taking into consideration noise
reduction. The circuit components are designed based on the 0.35mm CMOS technology.
A physical layout is developed for fabrication purposes. This technology was chosen with
consideration of robustness, costliness and performance. The current reference is capable of
outputting a stable 12nA current, which may remain stable in a broad range of power supply
voltages with a minimum voltage of 1.6V. The operational amplifier operates correctly at
voltages as low as 1.5V. The amplifier power consumption is extremely low, around 8mW,
with an optimal quiescent current and minimum current preservation in the output stage.A principal contribuição desta dissertação é a implementação de circuitos integrados de
muito baixo consumo e alta eficiência, prontos a ser implementados num circuito de extração
de energia com base num elemento piezoelétrico.
Esta tese foca-se no desenvolvimento de um circuito de referência de corrente e um
amplificador operacional com baixa exigência de consumo. Uma revisão da literatura
é realizada, incluindo introdução à tecnologia Complementary Metal-Oxide-Semiconductor
(CMOS), e implementação de conhecidos circuitos de baixo consumo. Várias implementações
de referência de tensão e corrente são consideradas, e amplificadores operacionais também.
Uma referência de corrente auto polarizada com extremo baixo consumo é desenvolvida e
verificada. Um amplificador operacional original é proposto com uma topologia de seleção
de corrente mínima. Este circuito é constituído por três estágios, com um estágio de saída
de classe AB, e um circuito translinear. O circuito tem em consideração redução de ruído na
sua implementação.
Os circuitos são desenvolvidos com base na tecnologia 0.35mm CMOS. Uma layout foi
também desenhada com o propósito de fabricação. A tecnologia foi escolhida tendo em
conta o seu custo versus desempenho.
A referência de corrente produz uma corrente de 12nA, permanecendo estável para
tensões de alimentação de variáveis, com uma tensão mínima de 1.6V. O circuito mostra um
coeficiente de temperatura satisfatório. O amplificador operacional funciona com tensão de
alimentação mínima de 1.5V, com um consumo baixo de 8mW, com uma corrente mínima
mantida no estágio de saída
Cumulative Index to NASA Tech Briefs, 1963 - 1966
Cumulative index of NASA Tech Briefs dealing with electrical and electronic, physical science and energy sources, materials and chemistry, life science, and mechanical innovation
Cumulative index to NASA Tech Briefs, 1963-1967
Cumulative index to NASA survey on technology utilization of aerospace research outpu
NASA Tech Briefs Index, 1977, volume 2, numbers 1-4
Announcements of new technology derived from the research and development activities of NASA are presented. Abstracts, and indexes for subject, personal author, originating center, and Tech Brief number are presented for 1977
NASA contributions to fluidic systems: A survey
A state-of-the art review of fluidic technology is presented. It is oriented towards systems applications rather than theory or design. It draws heavily upon work performed or sponsored by NASA in support of the space program and aeronautical research and development (R&D). Applications are emphasized in this survey because it is hoped that the examples described and the criteria presented for evaluating the suitability of fluidics to new applications will be of value to potential users of fluidic systems. This survey of the fluidics industry suggests some of the means whereby a company may use a fluidic system effectively either to manufacture a product or as part of the end product
Electronics for Sensors
The aim of this Special Issue is to explore new advanced solutions in electronic systems and interfaces to be employed in sensors, describing best practices, implementations, and applications. The selected papers in particular concern photomultiplier tubes (PMTs) and silicon photomultipliers (SiPMs) interfaces and applications, techniques for monitoring radiation levels, electronics for biomedical applications, design and applications of time-to-digital converters, interfaces for image sensors, and general-purpose theory and topologies for electronic interfaces
Cumulative index to NASA Tech Briefs, 1963-1965
Annotated bibliography of NASA technical briefs on electrical, energy sources, materials, life sciences, and mechanical informatio
Intensity based interrogation of optical fibre sensors for industrial automation and intrusion detection systems
In this study, the use of optical fibre sensors for intrusion detection and industrial automation systems has been demonstrated, with a particular focus on low cost, intensity-based, interrogation techniques. The use of optical fibre sensors for intrusion detection systems to secure residential, commercial, and industrial premises against potential security breaches has been extensively reviewed in this thesis. Fibre Bragg grating (FBG) sensing is one form of optical fibre sensing that has been underutilised in applications such as in-ground, in-fence, and window and door monitoring, and addressing that opportunity has been a major goal of this thesis. Both security and industrial sensor systems must include some centralised intelligence (electronic controller) and ideally both automation and security sensor systems would be controlled and monitored by the same centralised system. Optical fibre sensor systems that could be used for either application have been designed, developed, and tested in this study, and optoelectronic interfaces for integrating these sensors with electronic controllers have been demonstrated. The versatility of FBG sensors means that they are also ideal for certain mainstream industrial applications.
Two novel transducers have been developed in this work; a highly sensitive low pressure FBG diaphragm transducer and a FBG load cell transducer. Both have been designed to allow interrogation of the optical signal could occur within the housing of the individual sensors themselves. This is achieved in a simple and low cost manner that enables the output of the transducers to be easily connected to standard electronic controllers, such as programmable logic controllers. Furthermore, some of the nonlinear characteristics of FBG sensors have been explored with the aim of developing transducers that are inherently decoupled from strain and temperature interference. One of the major advantages of optical fibre sensors is their ability to be both time division and wavelength division multiplexed. The intensity-based interrogation techniques used here complement this attribute and are a major consideration when developing the transducers and optoelectronic circuits. A time division multiplexing technique, using transmit-reflect detection and incorporating a dual bus, has also been developed. This system architecture enables all the different optical fibre transducers on the network to have the same Bragg wavelength and hence the number of spare replacement transducers required is minimal. Moreover, sensors can be replaced in an online control system without disrupting the network. In addition, by analysing both the transmitted and reflected signals, problems associated with optical power fluctuations are eliminated and the intensity of the sensor signals is increased through differential amplification.
Overall, the research addresses the limitations of conventional electrical sensors, such as susceptibility to corrosive damage in wet and corrosive environments, and risk of causing an explosion in hazardous environments, as well as the limitations of current stand-alone optical fibre sensor systems. This thesis supports more alert, reliable, affordable, and coordinated, control and monitoring systems in an on-line environment
Index to NASA Tech Briefs, 1974
The following information was given for 1974: (1) abstracts of reports dealing with new technology derived from the research and development activities of NASA or the U.S. Atomic Energy Commission, arranged by subjects: electronics/electrical, electronics/electrical systems, physical sciences, materials/chemistry, life sciences, mechanics, machines, equipment and tools, fabrication technology, and computer programs, (2) indexes for the above documents: subject, personal author, originating center
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