CMOS technology scaling has resulted in reduced supply voltage and intrinsic voltage gain of the transistor. This presents challenges to the analog circuit designers due to lower signal swing and achievable signal to noise ratio (SNR), leading to increased power consumption. At the same time, device speed has increased in lower design nodes, which has not been directly beneficial for analog circuit design. This thesis presents voltage-domain and time-domain circuit scaling friendly circuit architectures that minimize the power consumption and benefit from the increasing transistor speeds. In the voltage-domain, an on-the-fly gain selection block is demonstrated as an alternative to the traditional MDAC architecture to enhance the input dynamic range of a medium-resolution medium-speed analog-to-digital converter (ADC) at reduced supply voltages. The proposed design also eliminates the need for a reference buffer, thus providing power savings. The measured prototype enhances the input dynamic range of a 12bit, 40MSPS ADC to 80.6dB at 1.2V supply voltage. In the time-domain, a generic circuit design approach is presented, followed by an in-depth analysis of Voltage-Controlled-Oscillator based Operational Transconductance Amplifiers (VCO-OTAs). A discrete-time-domain small-signal model based on the zero crossings of the internal VCOs is developed to predict the stability, the step response, and the frequency response of the circuit when placed in feedback. The model accurately predicts the circuit behavior for an arbitrary input frequency, even as the VCO free-running frequency approaches the unity-gain bandwidth of the closed-loop system, where other intuitive small-signal models available in the literature fail. Next, we present an application of VCO-OTA in designing a baseband trans-impedance amplifier (TIA) for current-mode receivers as a scaling-friendly and power-efficient alternative to the inverter-based OTA. We illustrate a design methodology for the choice of the VCO-OTA parameters in the context of a receiver design with an example of a 20MHz RF-channel-bandwidth receiver operating at 2GHz. Receiver simulation results demonstrate an improvement of up to 12dB in blocker 1dB compression point (B1dB) for slightly higher power consumption or up to 2.6x power reduction of the TIA resulting in up to 2x power reduction of the receiver for similar B1dB performance. Next, we present some examples of VCO-OTAs. We first illustrate the benefit of a VCO-OTA in a low-dropout-voltage regulator to achieve a dropout voltage of only100mV and operating down to 0.8V input supply, compared to the prototype based on traditional OTA with a minimum dropout voltage of 150mV, operating at a minimum of 1.2V supply. Both the capacitor-less prototypes can drive up to 1nF load capacitor and provide a current of 60mA. The next prototype showcases a method to reduce the power consumption of a VCO-OTA and spurs at the VCO frequency, with an application in the design of a fourth-order Butterworth filter at 4MHz. The thesis concludes with a design example of 0.2V VCO-OTA.

The Light-emitting diodes (LEDs) are rapidly emerging as the dominant light source given their high luminous efficacy, long lift span, and thanks to the newly enacted efficiency standards in favor of the more environmentally-friendly LED technology. The LED lighting market is expected to reach USD 105.66 billion by 2025. As such, the lighting industry requires LED drivers, which essentially are power converters, with high efficiency, wide input/output range, low cost, small form factor, and great performance in power factor, and luminance flicker. These requirements raise new challenges beyond the traditional power converter topologies. On the other hand, the development and improvement of new device technologies such as printed thin-film capacitors and integrated high voltage/power devices opens up many new opportunities for mitigating such challenges using innovative circuit design techniques and solutions. Almost all electric products needs certain power delivery, regulation or conversion circuits to meet the optimized operation conditions. Designing a high performance power converter is a real challenge given the market’s increasing requirements on energy efficiency, size, cost, form factor, EMI performance, human health impact, and so on. The design of a LED driver system covers from high voltage AC/DC and DC/DC power converters, to high frequency low voltage digital controllers, to power factor correction (PFC) and EMI filtering techniques, and to safety solutions such as galvanic isolation. In this thesis, we study design challenges and present corresponding solutions to realize highly integrated and high performance LED drivers combining switched-capacitor and resonant converters, applying re-configurable multi-level circuit topology, utilizing sigma delta modulation, and exploring capacitive galvanic isolation. A hybrid switched-capacitor-resonant (HSCR) LED driver based on a stackable switched-capacitor (SC) converter IC rated for 15 to 20 W applications. Bulky transformers have been replaced with a SC ladder to perform high-efficiency voltage step-down conversion; an L-C resonant output network provides almost lossless current regulation and demonstrates the potential of capacitive galvanic isolation. The integrated SC modules can be stacked in the voltage domain to handle a large range of input voltage ranges that largely exceed the voltage limitation of the medium-voltage-rated 120 V silicon technology. The LED driver demonstrates > 91% efficiency over a rectified input DC voltage range from 160 VDC to 180 VDC with two stacked ICs; using a stack of four ICs > 89.6% efficiency is demonstrated over an input range from 320 VDC to 360 VDC . The LED driver can dim its output power to around 10% of the rated power while maintaining >70% efficiency with a PWM controlled clock gating circuit. Next, the design of AC main rectifier and inverter front end with sigma delta modulation is described. The proposed circuits features a pair of sigma delta controlled multilevel converters. The first is a multilevel rectifier responsible for PFC and dimming. The second is a bidirectional multilevel inverter used to cancel AC power ripple from the DC bus. The system also contains an output stage that powers the LEDs with DC and provides for galvanic isolation. Its functional performance indicates that integrated multilevel converters are a viable topology for lighting and other similar applications.

京都大学 / 0048 / 新制・論文博士 / 博士(工学) / 乙第12984号 / 論工博第4131号 / 新制||工||1637(附属図書館) / 32454 / 京都大学大学院工学研究科電子物性工学専攻 / (主査)教授 北野 正雄, 教授 竹内 繁樹, 准教授 久門 尚史 / 学位規則第4条第2項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

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No description available.

published_or_final_version / abstract / Electrical and Electronic Engineering / Master / Master of Philosophy

Areas which require high-temperature MOS circuits are instrumentations for geothermal and petroleum well-logging, space exploration, aero-propulsion systems, and other hostile environments. MOS digital circuits at high temperature are examined as well as the maximum operating temperature of MOS devices. Factors affecting high-temperature operation of these devices, including threshold voltage sensitivity, mobility degradation, leakage current characterization and interactions, zero-TC current in analog applications and reliability considerations, are discussed. Methods to reduce threshold voltage sensitivities, process modifications to reduce leakage current density at high temperature, circuit techniques to eliminate the leakage current effects, diode compensation, CMOS thermal latch-up and MOS scaling rules at high temperature are investigated. Experimental results of epitaxial diodes to verify the leakage current reduction effect are discussed.

This dissertation investigates the implementation of S-parameter based network techniques for the analysis of multiconductor, high speed VLSI integrated circuit and packaging interconnects. The S-parameters can be derived from three categories of input parameters: (1) lossy quasi-static R,L,C and G, (2) lossy frequency dependent (dispersive) R,L,C,G and (3) the propagation constants, Γ, the characteristic impedance, Z(c) and the conductor eigencurrents, I, derived from full wave analysis. The S-parameter network techniques developed allow for: the analysis of periodic waveform excitation, the incorporation of externally measured or calculated scattering parameter data and large system analysis through macro decomposition. The inclusion of non-linear terminations has also been developed.

Reducing circuit complexity to minimize design turnaround time and maximize chip area utilization is the most evident problem in dealing with VLSI layout. Three suggestions have been recommended to reduce circuit complexity. They are using regular modules as design targets, using hierarchical top-down design as a design methodology, and using CAD as a design tool. These three suggestions are the basis of this dissertation project. In this dissertation, three silicon compilers were implemented which take an universal AHPL circuit description as an input and automatically translate it into SLA (Storage Logic Array), PPLA (Path Programmable Logic Array), and ULA (Uncommitted Logic Array) chip layout. The goal is to study different layout algorithms and to derive better algorithms for alternative VLSI structures. In order to make a precise chip area comparison of these three silicon compilers, real SLA and ULA circuits have been designed. Four typical AHPL descriptions of different circuits or varying complexity were chosen as comparison examples. The result shows that the SLA layout requires least area for circuit realization generally. The PPLA approach is the worst one for large scale circuit realization, while the ULA lies in between.

by C.Y. Ho. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1989. / Bibliography: leaves [147]-[148]