Power-efficient high-speed interface circuit techniques

Inter- and intra-chip connections have become the new challenge to enable the scaling of computing systems, ranging from mobile devices to high-end servers. Demand for aggregate I/O bandwidth has been driven by applications including high-speed ethernet, backplane micro-servers, memory, graphics, chip-to-chip and network onchip. I/O circuitry is becoming the major power consumer in SoC processors and memories as the increasing bandwidth demands larger per-pin data rate or larger I/O pin count per component. The aggregate I/O bandwidth has approximately doubled every three to four years across a diverse range of standards in different applications. However, in order to keep pace with these standards enabled in part by process-technology scaling, we will require more than just device scaling in the near future. New energy-efficient circuit techniques must be proposed to enable the next generations of handheld and high-performance computers, given the thermal and system-power limits they start facing. ^ In this work, we are proposing circuit architectures that improve energy efficiency without decreasing speed performance for the most power hungry circuits in high speed interfaces. By the introduction of a new kind of logic operators in CMOS, called implication operators, we implemented a new family of high-speed frequency dividers/prescalers with reduced footprint and power consumption. New techniques and circuits for clock distribution, for pre-emphasis and for driver at the transmitter side of the I/O circuitry have been proposed and implemented. At the receiver side, new DFE architecture and CDR have been proposed and have been proven experimentally

A Low-Power BFSK/OOK Transmitter for Wireless Sensors

In recent years, significant improvements in semiconductor technology have allowed consistent development of wireless chipsets in terms of functionality and form factor. This has opened up a broad range of applications for implantable wireless sensors and telemetry devices in multiple categories, such as military, industrial, and medical uses. The nature of these applications often requires the wireless sensors to be low-weight and energy-efficient to achieve long battery life. Among the various functions of these sensors, the communication block, used to transmit the gathered data, is typically the most power-hungry block. In typical wireless sensor networks, transmission range is below 10 meters and required radiated power is below 1 milliwatt. In such cases, power consumption of the frequency-synthesis circuits prior to the power amplifier of the transmitter becomes significant. Reducing this power consumption is currently the focus of various research endeavors. A popular method of achieving this goal is using a direct-modulation transmitter where the generated carrier is directly modulated with baseband data using simple modulation schemes. Among the different variations of direct-modulation transmitters, transmitters using unlocked digitally-controlled oscillators and transmitters with injection or resonator-locked oscillators are widely investigated because of their simple structure. These transmitters can achieve low-power and stable operation either with the help of recalibration or by sacrificing tuning capability. In contrast, phase-locked-loop-based (PLL) transmitters are less researched. The PLL uses a feedback loop to lock the carrier to a reference frequency with a programmable ratio and thus achieves good frequency stability and convenient tunability. This work focuses on PLL-based transmitters. The initial goal of this work is to reduce the power consumption of the oscillator and frequency divider, the two most power-consuming blocks in a PLL. Novel topologies for these two blocks are proposed which achieve ultra-low-power operation. Along with measured performance, mathematical analysis to derive rule-of-thumb design approaches are presented. Finally, the full transmitter is implemented using these blocks in a 130 nanometer CMOS process and is successfully tested for low-power operation

A GHz-range, High-resolution Multi-modulus Prescaler for Extreme Environment Applications

The generation of a precise, low-noise, reliable clock source is critical to developing mixed-signal and digital electronic systems. The applications of such a clock source are greatly expanded if the clock source can be configured to output different clock frequencies. The phase-locked loop (PLL) is a well-documented architecture for realizing this configurable clock source. Principle to the configurability of a PLL is a multi-modulus divider. The resolution of this divider (or prescaler) dictates the resolution of the configurable PLL output frequency. In integrated PLL designs, such a multi-modulus prescaler is usually sourced from a GHz-range voltage-controlled oscillator. Therefore, a fully-integrated PLL ASIC requires the development of a high-speed, high-resolution multi-modulus prescaler. The design challenges associated with developing such a prescaler are compounded when the application requires the device to operate in an extreme environment. In these extreme environments (often extra-terrestrial), wide temperature ranges and radiation effects can adversely affect the operation of electronic systems. Even more problematic is that extreme temperatures and ionizing radiation can cause permanent damage to electronic devices. Typical commercial-off-the-shelf (COTS) components are not able withstand such an environment, and any electronics operating in these extreme conditions must be designed to accommodate such operation. This dissertation describes the development of a high-speed, high-resolution, multi-modulus prescaler capable of operating in an extreme environment. This prescaler has been developed using current-mode logic (CML) on a 180-nm silicon-germanium (SiGe) BiCMOS process. The prescaler is capable of operating up to at least 5.4 GHz over a division range of 16-48 with a total of 27 configurable moduli. The prescaler is designed to provide excellent ionizing radiation hardness, single-event latch-up (SEL) immunity, and single-event upset (SEU) resistance over a temperature range of −180°C to 125°C

Projeto de um circuito divisor de frequência de ultra-baixo consumo de potência

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-graduação em Engenharia ElétricaEsta dissertação apresenta o projeto de um circuito Prescaler Dual-Modulus 8/9 (PDM), projetado para a tecnologia TSMC 0.18um, cujo interesse principal é o ultra-baixo consumo de potência. Serão apresentadas duas propostas de PDM, uma com o total objetivo de se obter o menor consumo, e outra com uma proposta de se obter uma freqüência de funcionamento máximo, porém sem perder o compromisso com o baixo consumo. Esta segunda proposta de PDM deve-se ao fato de serem largamente usados em circuitos PLL, onde se exige aplicações em freqüências mais elevadas. O regime de funcionamento dos transistores é de inversão fraca. Operando neste regime, se tornam muito susceptíveis a quaisquer variações dos parâmetros tecnológicos, tanto intrachip quanto interchip. Como solução, é realizado um estudo de três topologias de circuitos compensadores e proposta uma quarta topologia. Esta topologia proposta visa expandir a faixa de tensão de alimentação, a qual os transistores possam suportar sem que haja o risco de danificá-los. A compensação será feita através da técnica de polarização do substrato e do poço dos transistores, de modo que a tensão de polarização possa corrigir qualquer variação de Vt, Vdd ou até mesmo da temperatura. Foram utilizados simuladores de circuitos elétricos para obtenção dos resultados, e estes confirmaram os resultados satisfatórios dos projetos propostos. This dissertation presents the design of a Prescaler Dual-Modulus (PDM) circuit, designed for TSMC 0.18um technology, whose main interest is ultra-low power consumption. Two proposals for PDM's will be presented, one with the objective of obtaining ultra-low power consumption, and the other one with the aim of obtaining a higher maximum frequency, however without compromising the low power consumption. PDM circuits have a potencially wide use in PLL circuits, which demands appliance in high frequencies. The operation of the transistors is weak inversion. Operating in this regimen, they become very susceptible to any variations in the technological parameters, both intrachip and interchip. A solution, a study of three topologies of compensating circuits was carried out, and a fourth topology was proposed. This proposed topology aims at expanding the range of voltage supported by the transistors without a risk of damaging them. The compensation will be carried out through the technique of bulk bias of the transistors, in such a way the bias voltage can correct any variation in Vt, Vdd or even the temperature. Circuits simulators were used to obtain the results, and they were found to be very satisfactory

CMOS dual-modulus prescaler design for RF frequency synthesizer applications.

Ng Chong Chon.Thesis (M.Phil.)--Chinese University of Hong Kong, 2005.Includes bibliographical references (leaves 100-103).Abstract in English and Chinese.摘要 --- p.iiiAcknowledgments --- p.ivContents --- p.viList of Figures --- p.ixList of Tables --- p.xiiChapter Chapter 1 --- Introduction --- p.1Chapter 1.1 --- Motivation --- p.1Chapter 1.2 --- Thesis Organization --- p.4Chapter Chapter 2 --- DMP Architecture --- p.6Chapter 2.1 --- Conventional DMP --- p.6Chapter 2.1.1 --- Operating Principle --- p.7Chapter 2.1.2 --- Disadvantages --- p.10Chapter 2.2 --- Pre-processing Clock Architecture --- p.10Chapter 2.2.1 --- Operating Principle --- p.11Chapter 2.2.2 --- Advantages and Disadvantages --- p.12Chapter 2.3 --- Phase-switching Architecture --- p.13Chapter 2.3.1 --- Operating Principle --- p.13Chapter 2.3.2 --- Advantages and Disadvantages --- p.14Chapter 2.4 --- Summary --- p.15Chapter Chapter 3 --- Full-Speed Divider Design --- p.16Chapter 3.1 --- Introduction --- p.16Chapter 3.2 --- Working Principle --- p.16Chapter 3.3 --- Design Issues --- p.18Chapter 3.4 --- Device Sizing --- p.19Chapter 3.5 --- Layout Considerations --- p.20Chapter 3.6 --- Input Sensitivity --- p.22Chapter 3.7 --- Modeling --- p.24Chapter 3.8 --- Review on Different Divider Designs --- p.28Chapter 3.8.1 --- Divider with Dynamic-Loading Technique --- p.28Chapter 3.8.2 --- Divider with Negative-Slew Technique --- p.30Chapter 3.8.3 --- LC Injection-Locked Frequency Divider --- p.32Chapter 3.8.4 --- Dynamic True Single Phase Clock Frequency Divider --- p.34Chapter 3.9 --- Summary --- p.42Chapter Chapter 4 --- 3V 900MHz Low Noise DMP --- p.43Chapter 4.1 --- Introduction --- p.43Chapter 4.2 --- Proposed DMP Topology --- p.46Chapter 4.3 --- Circuit Design and Implementation --- p.49Chapter 4.4 --- Simulation Results --- p.51Chapter 4.5 --- Summary --- p.53Chapter Chapter 5 --- 1.5V 2.4GHz Low Power DMP --- p.54Chapter 5.1 --- Introduction --- p.54Chapter 5.2 --- Proposed DMP Topology --- p.56Chapter 5.3 --- Circuit Design and Implementation --- p.59Chapter 5.3.1 --- Divide-by-4 stage --- p.59Chapter 5.3.2 --- TSPC dividers --- p.63Chapter 5.3.3 --- Phase-selection Network --- p.63Chapter 5.3.4 --- Mode-control Logic --- p.64Chapter 5.3.5 --- Duty-cycle Transformer --- p.65Chapter 5.3.6 --- Glitch Problem --- p.66Chapter 5.3.7 --- Phase-mismatch Problem --- p.70Chapter 5.4 --- Simulation Results --- p.70Chapter 5.5 --- Summary --- p.74Chapter Chapter 6 --- 1.5V 2.4GHz Wideband DMP --- p.75Chapter 6.1 --- Introduction --- p.75Chapter 6.2 --- Proposed DMP Architecture --- p.75Chapter 6.3 --- Divide-by-4 Stage --- p.76Chapter 6.3.1 --- Current-switch Combining --- p.76Chapter 6.3.2 --- Capacitive Load Reduction --- p.77Chapter 6.4 --- Simulation Results --- p.81Chapter 6.5 --- Summary --- p.83Chapter Chapter 7 --- Experimental Results --- p.84Chapter 7.1 --- Introduction --- p.84Chapter 7.2 --- Equipment Setup --- p.84Chapter 7.3 --- Measurement Results --- p.85Chapter 7.3.1 --- 3V 900GHz Low Noise DMP --- p.85Chapter 7.3.2 --- 1.5V 2.4GHz Low Power DMP --- p.88Chapter 7.3.3 --- 1.5V 2.4GHz Wideband DMP --- p.93Chapter 7.3 --- Summary --- p.96Chapter Chapter 8 --- Conclusions and Future Works --- p.98Chapter 8.1 --- Conclusions --- p.98Chapter 8.2 --- Future Works --- p.99References --- p.100Publications --- p.10

Cmos Programmable Time Control Circuit Design For Phased Array Uwb Ground Penetrating Radar Antenna Beamforming

Phased array radar systems employ multiple antennas to create a radar beam that can be steered electronically. By manipulating the relative phase values of feeding signals among different antennas, the effective radiation pattern of the array can be synthesized to enhance the main lobe in a desired direction while suppressing the undesired side lobes in other directions. Hence the radar scanning angles can be electronically controlled without employing the bulky mechanical gimbal structure, which can significantly reduce radar system size, weight and power consumption. In recent years, phased array technologies have received great attentions and are explored in developing many new applications, such as smart communication systems, military radars, vehicular radar, etc. Most of these systems are narrow band systems, where the phase delays are realized with narrow band phase shifter circuits. For the impulse ground penetrating radar however, its operating frequency spans an ultrawide bandwidth. Therefore the traditional phase shifters are not applicable due to their narrow band nature. To resolve the issue, in this study, a true time delay approach is explored which can precisely control time delays for the feeding pulse signals among different antennas in the array. In the design, an on chip programmable delay generator is being developed using Global Foundry 0.18 µm 7 HV high voltage CMOS process. The time delay control is realized by designing a programmable phase locked loop (PLL) circuit which can generate true time delays ranging from 100 ps (picoseconds) to 500 ps with the step size of 25 ps. The PLL oscillator\u27s frequency is programmable from 100MHz to 500MHz through two reconfigurable frequency dividers in the feedback loop. As a result, the antenna beam angle can be synthesized to change from 9.59° to 56.4° with a step of 2.75°, and the 3dB beamwidth is 10°. The power consumption of the time delay circuit is very low, where the supply voltage is 1.8V and the average current is as low as 472uA

A Low Voltage Delta-Sigma Fractional Frequency Divider for Multi-band WSN Frequency Synthesizers

A 1 V low voltage delta-sigma fractional-N frequency divider for multi-band (780/868/915 MHz and 2.4 GHz) WSN frequency synthesizers is presented. The frequency divider consists of a dual-modulus prescaler, a pulse-swallow counter and a delta-sigma modulator. The high-speed and low-voltage phase-switching dual-modulus prescaler is used in the frequency divider. Low threshold voltage transistors are applied to overcome low voltage supply and forward phase-switching technique is adopted to prevent glitches. The modified delta-sigma modulator with long output sequence length and less spurs is adopted to minimize the fractional spurs. The frequency divider is designed in 0.18 mm TSMC RF CMOS technology under 1 V supply instead of the standard 1.8 V supply. The total chip area is 1190 mm 485 mm including I/O pads. The post simulation results show the frequency divider operates normally over a wide range of 1.3-5.0 GHz and the core circuit (without test buffers) consumes 2.3 mW

Review of Clocked Storage Elements in Digital Circuit Design

Storage of digital circuit is "state" or memory. These are called sequential circuits. The most fundamental sequential circuit type that we will ponder is known as the Flip-Flop. It is ponder four distinct assortments of these gadgets and their utilization in registers and register documents, which can be considered as one type of on– CPU memory. The traditional memory, called RAM, is ordinarily not on the CPU chip. Regular Slam and its assortments, including RAM, ROM, SRAM, Measure, and SDRAM. True single-phase clock (TSPC) method of reasoning has found wide use in advanced plan. At first as a quick topology, the TSPC structure in like manner eats up less power and includes less areas than various systems. In flip-flop plan only a single transistor is being clocked by short heartbeat get ready which is known as True Single Phase Clocking (TSPC) flip-flop

Cmos Programmable Time Control Circuit Design For Phased Array Uwb Ground Penetrating Radar Antenna Beamforming

Phased array radar systems employ multiple antennas to create a radar beam that can be steered electronically. By manipulating the relative phase values of feeding signals among different antennas, the effective radiation pattern of the array can be synthesized to enhance the main lobe in a desired direction while suppressing the undesired side lobes in other directions. Hence the radar scanning angles can be electronically controlled without employing the bulky mechanical gimbal structure, which can significantly reduce radar system size, weight and power consumption. In recent years, phased array technologies have received great attentions and are explored in developing many new applications, such as smart communication systems, military radars, vehicular radar, etc. Most of these systems are narrow band systems, where the phase delays are realized with narrow band phase shifter circuits. For the impulse ground penetrating radar however, its operating frequency spans an ultrawide bandwidth. Therefore the traditional phase shifters are not applicable due to their narrow band nature. To resolve the issue, in this study, a true time delay approach is explored which can precisely control time delays for the feeding pulse signals among different antennas in the array. In the design, an on chip programmable delay generator is being developed using Global Foundry 0.18 µm 7 HV high voltage CMOS process. The time delay control is realized by designing a programmable phase locked loop (PLL) circuit which can generate true time delays ranging from 100 ps (picoseconds) to 500 ps with the step size of 25 ps. The PLL oscillator\u27s frequency is programmable from 100MHz to 500MHz through two reconfigurable frequency dividers in the feedback loop. As a result, the antenna beam angle can be synthesized to change from 9.59° to 56.4° with a step of 2.75°, and the 3dB beamwidth is 10°. The power consumption of the time delay circuit is very low, where the supply voltage is 1.8V and the average current is as low as 472uA

Low phase noise 2 GHz Fractional-N CMOS synthesizer IC

Low noise low division 2 GHz RF synthesizer integrated circuits (ICs) are conventionally implemented in some form of HBT process such as SiGe or GaAs. The research in this dissertation differs from convention, with the aim of implementing a synthesizer IC in a more convenient, low-cost Si-based CMOS process. A collection of techniques to push towards the noise and frequency limits of CMOS processes, and possibly other IC processes, is then one of the research outcomes. In a synthesizer low N-divider ratios are important, as high division ratios would amplify in-band phase noise. The design methods deployed as part of this research achieve low division ratios (4 ≤ N ≤ 33) and a high phase comparison frequency (>100 MHz). The synthesizer IC employs a first-order fractional-N topology to achieve increased frequency tuning resolution. The primary N-divider was implemented utilising current mode logic (CML) and the fractional accumulator utilising conventional CMOS. Both a conventional CMOS phase frequency detector (PFD) and a CML PFD were implemented for benchmarking purposes. A custom-built 4.4 GHz synthesizer circuit employing the IC was used to validate the research. In the 4.4 GHz synthesizer circuit, the prototype IC achieved a measured in-band phase noise plateau of L( f ) = -113 dBc/Hz at a 100 kHz frequency offset, which equates to a figure of merit (FOM) of -225 dBc/Hz. The FOM compares well with existing, but expensive, SiGe and GaAs HBT processes. Total IC power dissipation was 710 mW, which is considerably less than commercially available GaAs designs. The complete synthesizer IC was implemented in Austriamicrosystems‟ (AMS) 0.35 μm CMOS process and occupies an area of 3.15 x 2.18 mm2.Dissertation (MEng)--University of Pretoria, 2010.Electrical, Electronic and Computer Engineeringunrestricte