A 10-b Two-Stage DAC with an Area-Efficient Multiple-Output Voltage Selector and a Linearity-Enhanced DAC-Embedded Op-Amp for LCD Column Driver ICs

[[abstract]]This work proposes a 10-b two-stage DAC with an area-efficient multiple-output voltage selector and a linearity-enhanced DAC-embedded op-amp for LCD column driver ICs. The proposed voltage selector is divided into two stages, MSB and LSB decoders; this design requires fewer switches compared with tree-type voltage selectors, enabling a smaller die area. The proposed 6-b two-voltage selector occupies only 61% of the area needed for a 6-b tree-type two-voltage selector. This study also develops a generalized architecture for an area-efficient voltage selector for multiple outputs. To improve the linearity of the DAC-embedded op-amp, the differential pairs operate at the edge of the saturation region. The 10-b DAC prototypes were produced with 0.35-mu m/0.5-mu m CMOS technology with the worst DNL/INL being 0.44/0.58 LSB.[[note]]SC

A 10-b Two-Stage DAC with an Area-Efficient Multiple-Output Voltage Selector and a Linearity-Enhanced DAC-Embedded Op-Amp for LCD Column Driver ICs

[[abstract]]This work proposes a 10-b two-stage DAC with an area-efficient multiple-output voltage selector and a linearity-enhanced DAC-embedded op-amp for LCD column driver ICs. The proposed voltage selector is divided into two stages, MSB and LSB decoders; this design requires fewer switches compared with tree-type voltage selectors, enabling a smaller die area. The proposed 6-b two-voltage selector occupies only 61% of the area needed for a 6-b tree-type two-voltage selector. This study also develops a generalized architecture for an area-efficient voltage selector for multiple outputs. To improve the linearity of the DAC-embedded op-amp, the differential pairs operate at the edge of the saturation region. The 10-b DAC prototypes were produced with 0.35-mu m/0.5-mu m CMOS technology with the worst DNL/INL being 0.44/0.58 LSB.[[note]]SC

Design and implementation of 4 bit binary weighted current steering DAC

A compact current-mode Digital-to-Analog converter (DAC) suitable for biomedical application is repesented in this paper .The designed DAC is binary weighted in 180nm CMOS technology with 1.8V supply voltage. In this implementation, authors have focused on calculaton of Non linearity error say INL and DNL for 4 bit DAC having various type of switches: NMOS, PMOS and Transmission Gate. The implemented DAC uses lower area and power compared to unary architecture due to absence of digital decoders. The desired value of Integrated non linearity (INL) and Differential non linearity (DNL) for DAC for are within a range of +0.5LSB. Result obtained in this works for INL and DNL for the case DAC using Transmission Gate is +0.34LSB and +0.38 LSB respectively with 22mW power dissipation

Diseño e implementación de un instrumento virtual para la adquisición y generación de señales.

SGandO, como se le ha denominado coloquialmente al proyecto realizado, comprende una parte hardware y una parte software que, unido a la realización de una PCB, reúne gran parte de los conocimientos adquiridos en una ingeniería industrial, en la rama de electrónica. Ya sea desde un PC o por medio de la misma placa donde se aloja la FPGA, SGandO nos permite generar señales del tipo senoidal, triangular y cuadrada en un amplio rango de frecuencias que van desde los hercios a los megahercios a diferentes magnitudes de voltaje, con la posibilidad de añadir offset y modificar el ciclo de trabajo de estas señales. El osciloscopio nos va a permitir visualizar las señales generadas, bien sean desde el propio generador de señales de SGandO o desde fuentes externas, siempre teniendo en cuenta los rangos de entrada permitidos. Entre sus características, cabe destacar la instalación de un amplificador de ganancia programable (PGA) que no distorsiona las señales con bajos niveles de amplitud y la posibilidad de utilizar el nivel del umbral de disparo así como el modo AC para eliminar la componente DC de la señal de entrada.SGandO, as we have named the completed project, includes hardware and software which, together to the fabrication of a PCB, comprises many topics of acquired knowledge in an Industrial Engineering, in the branch of Electronics. Either from a PC or through the board where is located the FPGA, SGandO allows us to generate signals of sinusoidal, triangular and square type in a wide range of frequencies ranging from hertz to megahertz with different voltage magnitudes, as well as the possibility of adding offset and modify the duty cycle of these signals. The oscilloscope will allow us to visualize the generated signals, from either the SGandO signal generator or external sources, always taking into account the allowed input ranges. Its features include the installation of a programmable gain amplifier that does not distort the signals with low amplitude levels and the possibility of using the trigger as well as the AC mode to eliminate the DC component of the input signal

Digital System Design - Use of Microcontroller

Embedded systems are today, widely deployed in just about every piece of machinery from toasters to spacecraft. Embedded system designers face many challenges. They are asked to produce increasingly complex systems using the latest technologies, but these technologies are changing faster than ever. They are asked to produce better quality designs with a shorter time-to-market. They are asked to implement increasingly complex functionality but more importantly to satisfy numerous other constraints. To achieve the current goals of design, the designer must be aware with such design constraints and more importantly, the factors that have a direct effect on them.One of the challenges facing embedded system designers is the selection of the optimum processor for the application in hand; single-purpose, general-purpose or application specific. Microcontrollers are one member of the family of the application specific processors.The book concentrates on the use of microcontroller as the embedded system?s processor, and how to use it in many embedded system applications. The book covers both the hardware and software aspects needed to design using microcontroller.The book is ideal for undergraduate students and also the engineers that are working in the field of digital system design.Contents• Preface;• Process design metrics;• A systems approach to digital system design;• Introduction to microcontrollers and microprocessors;• Instructions and Instruction sets;• Machine language and assembly language;• System memory; Timers, counters and watchdog timer;• Interfacing to local devices / peripherals;• Analogue data and the analogue I/O subsystem;• Multiprocessor communications;• Serial Communications and Network-based interfaces

Digital System Design - Use of Microcontroller

Embedded systems are today, widely deployed in just about every piece of machinery from toasters to spacecraft. Embedded system designers face many challenges. They are asked to produce increasingly complex systems using the latest technologies, but these technologies are changing faster than ever. They are asked to produce better quality designs with a shorter time-to-market. They are asked to implement increasingly complex functionality but more importantly to satisfy numerous other constraints. To achieve the current goals of design, the designer must be aware with such design constraints and more importantly, the factors that have a direct effect on them.One of the challenges facing embedded system designers is the selection of the optimum processor for the application in hand; single-purpose, general-purpose or application specific. Microcontrollers are one member of the family of the application specific processors.The book concentrates on the use of microcontroller as the embedded system?s processor, and how to use it in many embedded system applications. The book covers both the hardware and software aspects needed to design using microcontroller.The book is ideal for undergraduate students and also the engineers that are working in the field of digital system design.Contents• Preface;• Process design metrics;• A systems approach to digital system design;• Introduction to microcontrollers and microprocessors;• Instructions and Instruction sets;• Machine language and assembly language;• System memory; Timers, counters and watchdog timer;• Interfacing to local devices / peripherals;• Analogue data and the analogue I/O subsystem;• Multiprocessor communications;• Serial Communications and Network-based interfaces

Power and spectrally efficient integrated high-speed LED drivers for visible light communication

Recent trends in mobile broadband indicates that the available radio frequency (RF) spectrum will not be enough to support the data requirements of the immediate future. Visible light communication, which uses visible spectrum to transmit wirelessly could be a potential solution to the RF ’Spectrum Crunch’. Thus there is growing interest all over the world in this domain with support from both academia and industry. Visible light communication( VLC) systems make use of light emitting diodes (LEDs), which are semiconductor light sources to transmit information. A number of demonstrators at different data capacity and link distances has been reported in this area. One of the key problems holding this technology from taking off is the unavailability of power efficient, miniature LED drive schemes. Reported demonstrators, mostly using either off the shelf components or arbitrary waveform generators (AWGs) to drive the LEDs have only started to address this problem by adopting integrated drivers designed for driving lighting installations for communications. The voltage regulator based drive schemes provide high power efficiency (> 90 %) but it is difficult to realise the fast switching required to achieve the Mbps or Gbps data rates needed for modern wireless communication devices. In this work, we are exploiting CMOS technology to realise an integrated LED driver for VLC. Instead of using conventional drive schemes (digital to analogue converter (DAC) + power amplifier or voltage regulators), we realised a current steering DAC based LED driver operating at high currents and sampling rates whilst maintaining power efficiency. Compared to a commercial AWG or discrete LED driver, circuit realised utilisng complementary metal oxide semiconductor (CMOS) technology has resulted in area reduction (29mm2). We realised for the first time a multi-channel CMOS LED driver capable of operating up to a 500 MHz sample rate at an output current of 255 mA per channel and >70% power efficiency. We were able to demonstrate the flexibility of the driver by employing it to realise VLC links using micro LEDs and commercial LEDs. Data rates up to 1 Gbps were achieved using this system employing a multiple input, multiple output (MIMO) scheme. We also demonstrated the wavelength division multiplexing ability of the driver using a red/green/blue commercial LED. The first integrated digital to light converter (DLC), where depending on the input code, a proportional number of LEDs are turned ON, realising a data converter in the optical domain, is also an output from this research. In addition, we propose a differential optical drive scheme where two output branches of a current DAC are used to drive two LEDs achieving higher link performance and power efficiency compared to single LED drive

Adaptive torque-feedback based engine control

The aim of this study was to develop a self-tuning or adaptive SI engine controller using torque feedback as the main control variable, based on direct/indirect measurement and estimation techniques. The indirect methods include in-cylinder pressure measurement, ion current measurement, and crankshaft rotational frequency variation. It is proposed that torque feedback would not only allow the operating set-points to be monitored and achieved under wider conditions (including the extremes of humidity and throttle transients), but to actively select and optimise the set-points on the basis of both performance and fuel economy. A further application could allow the use of multiple fuel types and/or combustion enhancing methods to best effect. An existing experimental facility which comprised a Jaguar AJ-V8 SI engine coupled to a Heenan-Froude Dynamatic GVAL (Mk 1) dynamometer was adopted for this work, in order to provide a flexible distributed engine test system comprising a combined user interface and cylinder pressure monitoring system, a functional dynamometer controller, and a modular engine controller which is close coupled to an embedded PC has been created. The considerable challenges involved in creating this system have meant that the core research objectives of this project have not been met. Nevertheless, an open-architecture software and hardware engine controller and independent throttle controller have been developed, to the point of testing. For the purposes of optimum ignition timing validation and combustion knock detection, an optical cylinder pressure measurement system with crank angle synchronous sampling has been developed. The departure from the project’s initial aims have also highlighted several important aspects of eddy-current dynamometer control, whose closed-loop behaviour was modelled in Simulink to study its control and dynamic response. The design of the dynamometer real-time controller was successfully implemented and evaluated in a more contemporary context using an embedded digital controller.EThOS - Electronic Theses Online ServiceSchool of Mechanical & Systems EngineeringNewcastle UniversityGBUnited Kingdo

Optimising the NAOMI adaptive optics real-time control system

This thesis describes the author's research in the field of Real-Time Control (RTC) for Adaptive Optics (AO) instrumentation. The research encompasses experiences and knowledge gained working in the area of RTC on astronomical instrumentation projects whilst at the Optical Science Laboratories (OSL), University College London (UCL), the Isaac Newton Groups of Telescopes (ING) and the Centre for Advanced Instrumentation (СfAI), Durham University. It begins by providing an extensive introduction to the field of Astronomical Adaptive Optics covering Image Correction Theory, Atmospheric Theory, Control Theory and Adaptive Optics Component Theory. The following chapter contains a review of the current state of world wide AO instruments and facilities. The Nasmyth Adaptive Optics Multi-purpose Instrument (NAOMI), the common user AO facility at the 4.2 William Herschel Telescope (WHT), is subsequently described. Results of NAOMI component characterisation experiments are detailed to provide a system understanding of the improvement optimisation could offer. The final chapter investigates how upgrading the RTCS could increase NAOMI'S spatial and temporal performance and examines the RTCS in the context of Extremely Large Telescope (ELT) class telescopes