11,808 research outputs found

    STUDY OF FULLY-INTEGRATED LOW-DROPOUT REGULATORS

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    Department of Electrical EngineeringThis thesis focuses on the introduction of fully-integrated low-dropout regulators (LDOs). Recently, for the mobile and internet-of-things applications, the level of integration is getting higher. LDOs get popular in integrated circuit design including functions such as reducing switching ripples from high-efficiency regulators, cancelling spurs from other loads, and giving different supply voltages to loads. In accordance with load applications, choosing proper LDOs is important. LDOs can be classified by the types of power MOSEFT, the topologies of error amplifier, and the locations of dominant pole. Analog loads such as voltage-controlled oscillators and analog-to-digital converters need LDOs that have high power-supply-rejection-ratio (PSRR), high accuracy, and low noise. Digital loads such as DRAM and CPU need fast transient response, a wide range of load current providable LDOs. As an example, we present the design procedure of a fully-integrated LDO that obtains the desired PSRR. In analog LDOs, we discuss advanced techniques such as local positive feedback loop and zero path that can improve stability and PSRR performance. In digital LDOs, the techniques to improve transient response are introduced. In analog-digital hybrid LDOs, to achieve both fast transient and high PSRR performance in a fully-integrated chip, how to optimally combine analog and digital LDOs is considered based on the characteristics of each LDO type. The future work is extracted from the considerations and limitations of conventional techniques.clos

    Supercapacitor assisted LDO (SCALDO) techniquean extra low frequency design approach to high efficiency DC-DC converters and how it compares with the classical switched capacitor converters

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    Supercapacitor assisted low dropout regulators (SCALDO) were proposed as an alternative design approach to DC-DC converters, where the supercapacitor circulation frequency (switching frequency) is in the order of few Hz to few 10s of Hz, with an output stage based on a low dropout regulator stage. For converters such as 12–5V, 5–3.3V and 5–1.5V, the technique provides efficiency improvement factors of 2, 1.33 and 3 respectively, in compared to linear converters with same input-output combinations. In a 5–1.5V SCALDO regulator, using thin profile supercapacitors in the range of fractional farads to few farads, this translates to an approximate end to end efficiency of near 90%. However, there were concerns that this patented technique is merely a variation of well-known switched capacitor (charge pump) converters. This paper is aimed at providing a broad overview of the capability of SCALDO technique with generalized theory, indicating its capabilities and limitations, and comparing the practical performance with a typical switched capacitor converter of similar current capability

    A power sharing series power BJT array with isolated low voltage control for AC power control applications

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    A technique for a continuously variable AC resistance using a series BJT array is presented. This array provides high power dissipation capability and uniform voltage and power distribution across the individual transistors. The array, controlled using a set of optoisolators to maintain the electrical isolation between the control circuits and the power stage, could be used as the basis to develop several useful techniques including a solid state AC regulator with comparable performance to the commonly used ferro-resonant systems; a linear AC electronic load suitable for testing UPS and other power conditioners; and, in other AC power control applications such as switching capacitors in AC resonant circuits

    Asynchronous Circuit Stacking for Simplified Power Management

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    As digital integrated circuits (ICs) continue to increase in complexity, new challenges arise for designers. Complex ICs are often designed by incorporating multiple power domains therefore requiring multiple voltage converters to produce the corresponding supply voltages. These converters not only take substantial on-chip layout area and/or off-chip space, but also aggregate the power loss during the voltage conversions that must occur fast enough to maintain the necessary power supplies. This dissertation work presents an asynchronous Multi-Threshold NULL Convention Logic (MTNCL) “stacked” circuit architecture that alleviates this problem by reducing the number of voltage converters needed to supply the voltage the ICs operate at. By stacking multiple MTNCL circuits between power and ground, supplying a multiple of VDD to the entire stack and incorporating simple control mechanisms, the dynamic range fluctuation problem can be mitigated. A 130nm Bulk CMOS process and a 32nm Silicon-on-Insulator (SOI) CMOS process are used to evaluate the theoretical effect of stacking different circuitry while running different workloads. Post parasitic physical implementations are then carried out in the 32nm SOI process for demonstrating the feasibility and analyzing the advantages of the proposed MTNCL stacking architecture

    ASDTIC control and standardized interface circuits applied to buck, parallel and buck-boost dc to dc power converters

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    Versatile standardized pulse modulation nondissipatively regulated control signal processing circuits were applied to three most commonly used dc to dc power converter configurations: (1) the series switching buck-regulator, (2) the pulse modulated parallel inverter, and (3) the buck-boost converter. The unique control concept and the commonality of control functions for all switching regulators have resulted in improved static and dynamic performance and control circuit standardization. New power-circuit technology was also applied to enhance reliability and to achieve optimum weight and efficiency

    Integration of magnetic amplifier switch model into computer aided design for power converters

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    Зазвичай у джерелах вторинного електроживлення (ДВЕЖ) комутаційну та регулюючу функції виконують напівпровідникові компоненти. Однак вони не можуть забезпечити високу якість вихідних характеристик у багатоканальних джерелах живлення та в ДВЕЖ із високим рівнем струму навантаження. В таких випадках як силові ключі використовують високочастотні магнітні підсилювачі (ВМП) на основі аморфних магнітом’яких сплавів з прямокутною петлею гістерезису. Розроблення перетворювачів електроенергії на основі ВМП не є повністю автоматизованим. ВМП є магнітним компонентом з нелінійними властивостями. Системи автоматизованого проектування (САПР) для комп’ютерного імітаційного моделювання електричних кіл не призначені для розрахунків магнітних полів та працюють з дискретними електричними компонентами. Існує проблема інтеграції моделі компонента з магнітним гістерезисом у бібліотеку моделей САПР. Крім того, досить складно оцінити оптимальні параметри такого компонента. У статті запропоновано нову математичну модель силового ключа на основі ВМП, що ґрунтується на функції, яку можна генерувати з допомогою цифрових технологій. Досліджено цифровий генератор синуса, що складається з цифрових дискретних компнентів для моделювання силового ключа на основі ВМП. Запропоновану математичну модель силового ключа на основі ВМП інтегровано у САПР. Проведено комп’ютерне імітаційне моделювання електричного кола, що містить ВМП. Розраховано абсолютну похибку та середньоквадратичне відхилення моделі процесів перемагнічення ВМП у порівнянні з експериментально отриманими даними. Така часткова автоматизація процесу розроблення високочастотних перетворювачів електроенергії на основі ВМП суттєво зменшить його складність, тривалість і вартість, а також сприятиме розвиткові нових схемотехнічних рішень.The designing of electrical power converters based on Magnetic Amplifier (MagAmp) switches is not fully automated. MagAmp is a magnetic component with nonlinear properties. Computer aided design (CAD) programmes are built to simulate electric circuits without electromagnetic field with distributed components. There is a problem of integration of a model of a component with magnetic hysteresis into the set of CAD models. In addition, estimation of the optimal parameters of such a component is rather complicated. The article proposes a new model of MagAmp switch which is based on a function that can be generated using digital technology. The digital generator of sinusoidal signals, consisting of discrete digital components for modeling the MagAmp switch, is investigated. Integration of the model into CAD programme and simulation of the electric circuit, which includes MagAmp switch, are obtained. Partial automation will reduce complexity, duration and cost of the design procedure, and will enhance the development of power converters
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