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A Wide-Tuning Range 1.8 GHz Quadrature VCO Utilizing Coupled Ring Oscillators
Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
2006 (English)In: Proc. IEEE International Symposium on Circuits and Systems (ISCAS), 2006, 5143-5146 p.Conference paper, Published paper (Refereed)
Abstract [en]

This paper presents a fully integrated 1.8 GHz, 0.35-/spl mu/m CMOS quadrature voltage-controlled oscillator (QVCO) design. The topology uses coupled ring oscillators to produce quadrature outputs. In order to gain better phase noise performance LC-based filtering is introduced to QVCO. Also using variable inductance concept, a 1.2 GHz tuning range is achieved. According to simulation results, proposed QVCO draws 26.1 mA from 3.3V supply and exhibits a worst-case phase noise of -117.3 dBc/Hz at 1-MHz offset over the tuning range.

Place, publisher, year, edition, pages
2006. 5143-5146 p.
Keyword [en]
quadrature VCO, tuning range, coupled ring oscillators, CMOS
National Category
Engineering and Technology
Identifiers
URN: urn:nbn:se:liu:diva-14046DOI: 10.1109/ISCAS.2006.1693790OAI: oai:DiVA.org:liu-14046DiVA: diva2:22521
Available from: 2006-10-05 Created: 2006-10-05 Last updated: 2011-02-15Bibliographically approved
In thesis
1. Circuit Techniques for On-Chip Clocking and Synchronization
Open this publication in new window or tab >>Circuit Techniques for On-Chip Clocking and Synchronization
2006 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

Today’s microprocessors with millions of transistors perform high-complexity computing at multi-gigahertz clock frequencies. The ever-increasing chip size and speed call for new methodologies in clock distribution network. Conventional global synchronization techniques exhibit many drawbacks in the advanced VLSI chips such as high-speed microprocessors. A significant percentage of the total power consumption in a microprocessor is dissipated in the clock distribution network. Also since the chip dimensions increase, clock skew management becomes very challenging in the framework of conventional methodology. Long interconnect delays limit the maximum clock frequency and become a bottleneck for future microprocessor design. In such a situation, new alternative techniques for synchronization in system-on-chip are demanded.

This thesis presents new alternatives for traditional clocking and synchronization methods, in which, speed and power consumption bottlenecks are treated. For this purpose, two new techniques based on mesochronous synchronization and resonant clocking are investigated. The mesochronous synchronization technique deals with remedies for skew and delay management. Using this technique, clock frequency up to 5 GHz for on-chip communication is achievable in 0.18-μm CMOS process. On the other hand the resonant clocking solves significant power dissipation problem in the clock network. This method shows a great potential in power saving in very large-scale integrated circuits. According to measurements, 2.3X power saving in clock distribution network is achieved in 130-nm CMOS process. In the resonant clocking, oscillator plays a crucial role as a clock generator. Therefore an investigation about oscillators and possible techniques for jitter and phase noise reduction in clock generators has been done in this research framework. For this purpose a study of injection locking phenomenon in ring oscillators is presented. This phenomenon can be used as a jitter suppression mechanism in the oscillators. Also a new implementation of the DLL-based clock generators using ring oscillators is presented in 130-nm CMOS process. The measurements show that this structure operates in the frequency range of 100 MHz-1.5 GHz, and consumes less power and area compared to the previously reported structures. Finally a new implementation of a 1.8-GHz quadrature oscillator with wide tuning range is presented. The quadrature oscillators potentially can be used as future clock generators where multi-phase clock is needed.

Place, publisher, year, edition, pages
Institutionen för systemteknik, 2006. 58 p.
Series
Linköping Studies in Science and Technology. Thesis, ISSN 0280-7971 ; 1241
Keyword
Clocking-Synchronization-CMOS-Integrated Circuit
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-7505 (URN)91-85497-44-4 (ISBN)
Presentation
2006-04-11, Glashuset, House B, Campus Valla, Campus Valla, Linköpings universitet, 00:00 (English)
Opponent
Supervisors
Note
Report code: LiU-TEK-LIC-2006:22Available from: 2006-10-05 Created: 2006-10-05 Last updated: 2009-03-30
2. Low-Power Low-Jitter Clock Generation and Distribution
Open this publication in new window or tab >>Low-Power Low-Jitter Clock Generation and Distribution
2008 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Today’s microprocessors with millions of transistors perform high-complexitycomputing at multi-gigahertz clock frequencies. Clock generation and clockdistribution are crucial tasks which determine the overall performance of amicroprocessor. The ever-increasing power density and speed call for newmethodologies in clocking circuitry, as the conventional techniques exhibit manydrawbacks in the advanced VLSI chips. A significant percentage of the total dynamicpower consumption in a microprocessor is dissipated in the clock distributionnetwork. Also since the chip dimensions increase, clock jitter and skew managementbecome very challenging in the framework of conventional methodologies. In such asituation, new alternative techniques to overcome these limitations are demanded.

The main focus in this thesis is on new circuit techniques, which treat thedrawbacks of the conventional clocking methodologies. The presented research in thisthesis can be divided into two main parts. In the first part, challenges in design ofclock generators have been investigated. Research on oscillators as central elements inclock generation is the starting point to enter into this part. A thorough analysis andmodeling of the injection-locking phenomenon for on-chip applications show greatpotential of this phenomenon in noise reduction and jitter suppression. In thepresented analysis, phase noise of an injection-locked oscillator has been formulated.The first part also includes a discussion on DLL-based clock generators. DLLs haverecently become popular in design of clock generators due to ensured stability,superior jitter performance, multiphase clock generation capability and simple designprocedure. In the presented discussion, an open-loop DLL structure has beenproposed to overcome the limitations introduced by DLL dithering around the averagelock point. Experimental results reveals that significant jitter reduction can beachieved by eliminating the DLL dithering. Furthermore, the proposed structuredissipates less power compared to the traditional DLL-based clock generators.Measurement results on two different clock generators implemented in 90-nm CMOSshow more than 10% power savings at frequencies up to 2.5 GHz.

In the second part of this thesis, resonant clock distribution networks have beendiscussed as low-power alternatives for the conventional clocking schemes. In amicroprocessor, as clock frequency increases, clock power is going to be thedominant contributor to the total power dissipation. Since the power-hungry bufferstages are the main source of the clock power dissipation in the conventional clock distribution networks, it has been shown that the bufferless solution is the mosteffective resonant clocking method. Although resonant clock distribution shows greatpotential in significant clock power savings, several challenging issues have to besolved in order to make such a clocking strategy a sufficiently feasible alternative tothe power-hungry, but well-understood, conventional clocking schemes. In this part,some of these issues such as jitter characteristics and impact of tank quality factor onoverall performance have been discussed. In addition, the effectiveness of theinjection-locking phenomenon in jitter suppression has been utilized to solve the jitterpeaking problem. The presented discussion in this part is supported by experimentalresults on a test chip implemented in 130-nm CMOS at clock frequencies up to 1.8GHz.

Abstract [sv]

Mikroprocessorer till dagens datorer innehåller hundratals miljoner transistorersom utför åtskilliga miljarder komplexa databeräkningar per sekund. I stort settalla operationer i dagens mikroprocessorer ordnas genom att synkronisera demmed en eller flera klocksignaler. Dessa signaler behöver ofta distribueras överhela chippet och driva alla synkroniseringskretsar med klockfrekvenser pååtskilliga miljarder svängningar per sekund. Detta utgör en stor utmaning förkretsdesigners på grund av att klocksignalerna behöver ha en extremt högtidsnoggranhet, vilket blir svårare och svårare att uppnå då chippen blir större.Idealt ska samma klocksignal nå alla synkroniseringskretsar exakt samtidigt föratt uppnå optimal prestanda, avvikelser ifrån denna ideala funktionalitet innebärlägre prestanda. Ytterliggare utmaningar inom klockning av digitala chip, är atten betydande andel av processorns totala effekt förbrukas i klockdistributionen.Därför krävs nya innovativa kretslösningar för att lösa problemen med bådeonoggrannheten och den växande effektförbrukningen i klockdistributionen.

att lösa de problem som finns i dagens konventionella kretslösningar förklocksignaler på chip. I den första delen av denna avhandling presenterasforskningsresultat på oscillatorer vilka utgör mycket viktiga komponenter igeneringen av klocksignalerna på chippen. Teoretiska studier avfaslåsningsfenomen i integrerade klockoscillatorer har presenterats. Studiernahar visat att det finns stor potential för reducering av tidsonoggrannhet iklocksignalerna med hjälp av faslåsning till en annan signal. I avhandlingensförsta del presenteras även en diskussion om klockgeneratorer baserade påfördröjningslåsta element. Dessa fördröjningslåsta elementen, kända som DLLkretsar, har egenskapen att de kan fördröja en klocksignal med en bestämdfördröjning, vilket möjliggör skapandet av multipla klockfaser. En nykretsteknik har introducerats för klockgenerering av multipla klockfaser vilken reducerar effektförbrukningen och onoggranheten i DLL-baseradeklockgeneratorer. I denna teknik används en övervakningskrets vilken ser till attalla delar i klockgeneratorn utnyttjas effektivt och att oanvända kretsarinaktiveras. Baserat på experimentalla mätresultat från tillverkade testkretsar ikisel har en effektbesparing på mer än 10% uppvisats vid klockfrekvenser påupp till 2.5 GHz tillsammans med en betydande ökning av klocknoggranheten.

I avhandlingens andra del diskuteras en klockdistributionsteknik som baseraspå resonans, vilken har visat sig vara ett lovande alternativ till konventionllabufferdrivna klockningstekniker när det gäller minskande effektförbrukning.Principen bakom tekniken är att återanvända den energi som utnyttjas till attladda upp klocklasten. Teoretiska resonemang har visat att storaenergibesparingar är möjliga, och praktiska mätningar på tillverkadeexperimentchip har visat att effektförbrukingen kan mer än halveras. Ettproblem med den föreslagna klockningstekniken är att data som används iberäkningarna kretsen direkt påverkar klocklasten, vilket även påverkarnoggranheten på klocksignalen. För att komma till rätta med detta problemetpresenteras en teknik, baserad på forskning inom ovan nämndafaslåsningsfenomen, som kan minska onoggrannheten på klocksignalen medöver 50%. Både effektbesparingen och förbättringen av tidsnoggranheten harverifierats med hjälp av mätningar på tillverkade chip vid frekvenser upp mot1.8 GHz.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2008. 161 p.
Series
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 1208
Keyword
Low-power, resonant clock distribution, injection locking, DLL-based clock generation, jitter suppression, CMOS
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-14896 (URN)978-91-7393-817-4 (ISBN)
Public defence
2008-10-10, Visionen, Hus B, Campus Valla, Linköpings universitet, Linköping, 10:15 (English)
Opponent
Supervisors
Available from: 2008-09-29 Created: 2008-09-29 Last updated: 2017-07-07Bibliographically approved

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Mesgarzadeh, BehzadAlvandpour, Atila

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