Biopotential Readout Circuits for Portable Acquisition Systems

171 Pages·2009·6.91 MB·English

by  Dr. Refet Fırat Yazıcıoğlu

Biopotential Readout Circuits
for Portable Acquisition Systems
ANALOGCIRCUITSANDSIGNALPROCESSINGSERIES
ConsultingEditor:MohammedIsmail.OhioStateUniversity
TitlesinSeries:
OMNIDIRECTIONALINDUCTIVEPOWERINGFORBIOMEDICALIMPLANTS
Lenaerts,Bert,Puers,Robert
ISBN:978-1-4020-9074-5
BIOPOTENTIALREADOUTCIRCUITSFORPORTABLEACQUISITIONSYSTEMS
Yazicioglu,RefetFirat,VanHoof,Chris,Puers,Robert
ISBN:978-1-4020-9092-9
STRUCTUREDANALOGCMOSDESIGN
Stefanovic,Danica,Kayal,Maher
ISBN:978-1-4020-8572-7
LOWPOWERUWBCMOSRADARSENSORS
Paulino,Nuno,Goes,João,SteigerGarção,Adolfo
ISBN:978-1-4020-8409-6
ANALYSISANDDESIGNOFQUADRATUREOSCILLATORS
Oliveira,L.B.,Fernandes,J.R.,Filanovsky,I.M.,Verhoeven,C.J.M.,Silva,M.M.
ISBN:978-1-4020-8515-4
THEGM/IDDESIGNMETHODOLOGYFORCMOSANALOGLOWPOWER
INTEGRATEDCIRCUITS
Jespers,PaulG.A.
ISBN-10:0-387-47100-6
LOW-POWERHIGH-SPEEDADCSFORNANOMETERCMOSINTEGRATION
Cao,Zhiheng,Yan,Shouli
ISBN:978-1-4020-8449-2
SUBSTRATENOISECOUPLINGINRFICS
Helmy,Ahmed,Ismail,Mohammed
ISBN:978-1-4020-8165-1
CIRCUITANDINTERCONNECTDESIGNFORHIGHBIT-RATEAPPLICATIONS
Veenstra,Hugo,Long,JohnR.
ISBN:978-1-4020-6882-9
HIGH-RESOLUTIONIF-TO-BASEBANDSIGMADELTAADCFORCARRADIOS
Silva,PauloG.R.,Huijsing,JohanH.
ISBN:978-1-4020-8163-7
MULTI-BANDRFFRONT-ENDSWITHADAPTIVEIMAGEREJECTION
ADECT/BLUETOOTHCASESTUDY
Vidojkovic,V.,vanderTang,J.,Leeuwenburgh,A.,vanRoermund,A.H.M.
ISBN:978-1-4020-6533-0
SILICON-BASEDRFFRONT-ENDSFORULTRAWIDEBANDRADIOS
Safarian,Aminghasem,Heydari,Payam
ISBN:978-1-4020-6721-1
DESIGNOFHIGHVOLTAGEXDSLLINEDRIVERSINSTANDARDCMOS
Serneels,Bert,Steyaert,Michiel
ISBN:978-1-4020-6789-1
HIGH-LEVELMODELINGANDSYNTHESISOFANALOGINTEGRATEDSYSTEMS
Martens,EwoutS.J.,Gielen,Georges
ISBN:978-1-4020-6801-0
BASEBANDANALOGCIRCUITSFORSOFTWAREDEFINEDRADIO
Giannini,Vito,Craninckx,Jan,Baschirotto,Andrea
ISBN:978-1-4020-6537-8
CMOSMULTI-CHANNELSINGLE-CHIPRECEIVERSFORMULTI-GIGABITOPT...
Muller,P.,Leblebici,Y.
ISBN978-1-4020-5911-7
ANALOG-BASEBANDARCHITECTURESANDCIRCUITS
FORMULTISTANDARDANDLOW-VOLTAGEWIRELESSTRANSCEIVERS
Mak,PuiIn,U,Seng-Pan,Martins,RuiPaulo
ISBN:978-1-4020-6432-6
FULL-CHIPNANOMETERROUTINGTECHNIQUES
Ho,Tsung-Yi,Chang,Yao-Wen,Chen,Sao-Jie
ISBN:978-1-4020-6194-3
Refet Fırat Yazıcıog˘lu Chris Van Hoof
• •
Robert Puers
Biopotential Readout Circuits
for Portable Acquisition Systems
Dr.RefetFıratYazıcıog˘lu Prof.Dr.RobertPuers
KatholiekeUniversiteitLeuven KatholiekeUniversiteitLeuven
InteruniversityMicroelectronics Dept.ElectricalEngineering
Center(IMEC) (ESAT)
Kapeldreef75 KasteelparkArenberg10
3001Leuven 3001Leuven
Heverlee Belgium
Belgium Email:[email protected]
Email:fi[email protected]
Prof.Dr.ChrisVanHoof
KatholiekeUniversiteitLeuven
InteruniversityMicroelectronics
Center(IMEC)
Kapeldreef75
3001Leuven
Heverlee
Belgium
Email:[email protected]
ISBN 978-1-4020-9092-9 e-ISBN 978-1-4020-9093-6
LibraryofCongressControlNumber:2008934402
AllRightsReserved
©2009SpringerScience+BusinessMediaB.V.
Nopartofthisworkmaybereproduced,storedinaretrievalsystem,ortransmittedinanyformorby
anymeans,electronic,mechanical,photocopying,microfilming,recordingorotherwise,withoutwritten
permissionfromthePublisher,withtheexceptionofanymaterialsuppliedspecificallyforthepurpose
ofbeingenteredandexecutedonacomputersystem,forexclusiveusebythepurchaserofthework.
Printedonacid-freepaper
9 8 7 6 5 4 3 2 1
springer.com
Tomyparentsandsister,Hüseyin,Betil,and
GözdeYazıcıog˘lu;
andtomywife,BegümYazıcıog˘lu
Acknowledgements
BeforethestartofthistextIwouldliketoexpressmysinceregratitudetofriends,
colleagues,andfamily.
Firstofall,Iwouldliketoexpressmyappreciationandthankstomysupervisors
Prof. Chris Van Hoof and Prof. Robert Puers for their valuable guidance, support
andcomments.
IwouldliketothankmyM.S.thesissupervisorProf.TayfunAkinandMETU-
MEMSgroupmembers.Prof.Akinisactuallytheperson,whohasintroducedme
tomicroelectronicsandcircuitdesign.
IwouldliketothankthemembersofULPEXELteamofIMECvzw,Belgium.
Tostartwith,manythanksgoestoProf.PatrickMerkenforthevaluablediscussions
andguidanceandalsoforturningtheofficeenvironmentintoafunplace.Iwould
liketothankTomTorfsforhishelpsduringthetestingoftheASICsanddiscussions
we had about the system implementations. He has written lots of test softwares
for me. I would like to thank Jan Putzeys for helping me during the usage of the
instruments in his lab. Many thanks also go to Munir Abdalla, Ybe Creten, Inge
Doms, Burak Okcan, Junaid Aslam, and Tim Souverijns for the enjoyable office
andresearchenvironmentthattheyhavecreatedatIMEC.Ialsowouldliketothank
manypastandpresentcolleagues.Justafewtoname:MehmetAkifErismis,Deniz
Sabuncuoglu, Didem Ernur, Mustafa Badaroglu, Kris Verheyen, Koen De Munck,
CarolineGeuens,HerculesPereiraNeves,ChristopheWinters,XavierRottenberg,
KubaRaczkowski,TomSterken,FreVanaverbeke,andVladimirLeonov.
I am grateful to IMEC and the Katholieke Universiteit Leuven (K.U. Leuven).
BothIMECandK.U.LeuvenprovidemethenecessarymeanstoconductmyPh.D.
research in an excellent environment. I am also grateful to the employees of IN-
VOMEC department, Steve Mattheus, Greta Milzanowski, Marc Van Eylen, and
Kurt Van Genechten, for their patience to my endless questions and for their help
withallmysoftwareandtape-outrelatedproblems.
I would like to thank my dear friends, Arda, Sencer, and Emrah for the fun we
hadforallthoseyears.OtherfriendstomentionareRana,Ozlem,andOnur.Ialso
would like to express my sincere greetings to my cousin and her husband, Tugba
andFatihVardareli.
I would like to opena specialparagraph for my parents and my sister. Without
their unlimited love and support, it would not be possible to overcome the tough
challengesofPh.D.researchandlivingabroad.Iamgratefultothemandmylove
forthemisendless.Ialsowouldliketothankmyaunt,YildizSakin,andmygrand-
father,HilmiGozen,whoareascloseasamotherandafathertome.Whenitcomes
tothankmywife,BegumYuksel,wordsarejustnotenough.Iamgratefulforher
patienceandsupportforme.
Leuven,Belgium RefetFıratYazıcıog˘lu
July2008
vii
Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 AmbulatoryHealthCareSystems . . . . . . . . . . . . . . . . . . 1
1.2 BodyAreaNetworks. . . . . . . . . . . . . . . . . . . . . . . . . 1
1.3 ScopeoftheBook . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2 IntroductiontoBiopotentialAcquisition . . . . . . . . . . . . . . . . 5
2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.2 IntroductiontoBiopotentialSignals . . . . . . . . . . . . . . . . . 5
2.3 IntroductiontoBiopotentialElectrodes . . . . . . . . . . . . . . . 6
2.3.1 EquivalentCircuitModel . . . . . . . . . . . . . . . . . . 7
2.3.2 TypesofBiopotentialElectrodes . . . . . . . . . . . . . . 8
2.4 IntroductiontoBiopotentialAmplifiers . . . . . . . . . . . . . . . 9
2.4.1 InterferenceTheory . . . . . . . . . . . . . . . . . . . . . 10
2.4.2 Noise-EfficiencyFactor(NEF)ofBiopotentialAmplifiers . 11
2.4.3 State-of-the-ArtinInstrumentationAmplifierDesign . . . 12
2.5 IntroductiontoChopperModulationTechnique. . . . . . . . . . . 13
2.5.1 NoiseAnalysisofChopperModulationTechnique . . . . . 14
2.5.2 Charge Injection and Residual Offset of Chopper
ModulatedAmplifiers . . . . . . . . . . . . . . . . . . . . 15
2.5.3 SignalDistortioninChopperModulatedAmplifiers . . . . 17
2.5.4 CMRRoftheChopperModulatedAmplifiers . . . . . . . 18
2.6 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
3 24-ChannelEEGReadoutFront-EndASIC . . . . . . . . . . . . . . 21
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3.2 ASICArchitecture . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3.3 CurrentBalancingIA . . . . . . . . . . . . . . . . . . . . . . . . 22
3.3.1 Implementation . . . . . . . . . . . . . . . . . . . . . . . 22
3.3.2 MeasurementofPerformance . . . . . . . . . . . . . . . . 24
3.4 CMRRModelforBiopotentialInstrumentationAmplifiers. . . . . 25
3.4.1 SystematicCMRR . . . . . . . . . . . . . . . . . . . . . . 26
3.4.2 CMRRLimitDuetoDifferentialDCElectrodeOffset . . . 28
3.4.3 VerificationoftheCMRRModel . . . . . . . . . . . . . . 29
3.5 ProgrammableGainStage . . . . . . . . . . . . . . . . . . . . . . 30
3.5.1 Finite-GainCompensatedSCAmplifier. . . . . . . . . . . 30
3.5.2 ProgrammableGainStageImplementation . . . . . . . . . 32
3.6 TestResults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
3.7 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
ix
x Contents
4 BiopotentialReadoutFront-EndASICs . . . . . . . . . . . . . . . . 39
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
4.2 ACCoupledChopperModulatedIA(ACCIA) . . . . . . . . . . . 40
4.2.1 ArchitectureoftheACCIA . . . . . . . . . . . . . . . . . 40
4.2.2 ArchitectureoftheCBIA . . . . . . . . . . . . . . . . . . 44
4.2.3 Power-NoisePerformanceoftheACCIA . . . . . . . . . . 48
4.3 ChoppingSpikeFilter(CSF) . . . . . . . . . . . . . . . . . . . . 50
4.4 Low-PowerProgrammableGainStage . . . . . . . . . . . . . . . 51
4.5 Single-ChannelExGReadoutFront-End . . . . . . . . . . . . . . 53
4.5.1 Implementation . . . . . . . . . . . . . . . . . . . . . . . 53
4.5.2 MeasurementofPerformance . . . . . . . . . . . . . . . . 56
4.5.3 BiologicalTestResults . . . . . . . . . . . . . . . . . . . 61
4.6 Eight-ChannelEEGReadoutFront-End. . . . . . . . . . . . . . . 63
4.6.1 Implementation . . . . . . . . . . . . . . . . . . . . . . . 63
4.6.2 MeasurementofPerformance . . . . . . . . . . . . . . . . 68
4.6.3 BiologicalTestResults . . . . . . . . . . . . . . . . . . . 71
4.7 ComparisonwiththeState-of-the-Art . . . . . . . . . . . . . . . . 75
4.8 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
5 ACompleteBiopotentialAcquisitionASIC . . . . . . . . . . . . . . 79
5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
5.2 ASICArchitecture . . . . . . . . . . . . . . . . . . . . . . . . . . 79
5.3 BiasGeneratorCircuit . . . . . . . . . . . . . . . . . . . . . . . . 81
5.4 Class-ABBufferArchitecture . . . . . . . . . . . . . . . . . . . . 85
5.5 ACCIAwithCoarse-FineServo-Loop. . . . . . . . . . . . . . . . 86
5.5.1 StructureoftheACCIA . . . . . . . . . . . . . . . . . . . 86
5.5.2 CoarseTransconductance(CGM)Stage. . . . . . . . . . . 90
5.5.3 FineTransconductance(FGM)Stage . . . . . . . . . . . . 94
5.5.4 IntegratorStage . . . . . . . . . . . . . . . . . . . . . . . 94
5.5.5 CurrentBalancingIA(CBIA)Architecture . . . . . . . . . 95
5.5.6 GainStage . . . . . . . . . . . . . . . . . . . . . . . . . . 97
5.5.7 ImplementationoftheACCIA . . . . . . . . . . . . . . . 97
5.5.8 FastStart-UpoftheACCIA . . . . . . . . . . . . . . . . . 99
5.5.9 Power-NoisePerformanceoftheACCIA . . . . . . . . . . 100
5.5.10 MeasurementofPerformance . . . . . . . . . . . . . . . . 102
5.5.11 ComparisonwithState-of-the-Art . . . . . . . . . . . . . . 105
5.6 ChoppingSpikeFilter . . . . . . . . . . . . . . . . . . . . . . . . 106
5.7 Low-PowerProgrammableGainStage . . . . . . . . . . . . . . . 107
5.8 ReadoutFront-EndChannelTestResults . . . . . . . . . . . . . . 109
5.9 SquareWaveRelaxationOscillator . . . . . . . . . . . . . . . . . 110
5.10 Analog-to-DigitalConverter . . . . . . . . . . . . . . . . . . . . . 113
5.10.1 BasicOperationPrinciple . . . . . . . . . . . . . . . . . . 113
5.10.2 Architecture . . . . . . . . . . . . . . . . . . . . . . . . . 114
5.10.3 CapacitiveDACImplementation . . . . . . . . . . . . . . 117
5.10.4 Low-OffsetComparatorImplementation . . . . . . . . . . 119
Contents xi
5.10.5 TestResults . . . . . . . . . . . . . . . . . . . . . . . . . 123
5.11 ImpedanceMeasurementandCalibrationModes . . . . . . . . . . 125
5.12 BiologicalTestResults . . . . . . . . . . . . . . . . . . . . . . . 129
5.13 SummaryoftheBiopotentialAcquisitionASIC . . . . . . . . . . 129
5.14 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
6 WirelessBiopotentialAcquisitionSystems . . . . . . . . . . . . . . . 135
6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135
6.2 AWirelessVEMPAcquisitionSystem . . . . . . . . . . . . . . . 136
6.3 AWirelessTwo-ChannelExGAcquisitionSystem . . . . . . . . . 137
6.4 A1cm3WirelessEight-ChannelEEGAcquisitionSystem. . . . . 141
6.5 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145
7 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
7.1 Achievements . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
7.2 SuggestionsforFutureWork . . . . . . . . . . . . . . . . . . . . 149
Appendix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163
Symbols and Abbreviations
Symbols
A Common-modegainofanamplifier
CM
A Open-loopgainofanamplifier
v
BW −3dBbandwidthofanamplifier(Hz)
C Couplingcapacitorbetweenbodyandearthground
bg
C Couplingcapacitorbetweenbodyandmains
bp
C Isolationcapacitancebetweenearthgroundandbattery
iso
C Inputcapacitance
in
C Gate-oxidecapacitanceperunitarea(F/cm2)
ox
E Bandgapenergyofsilicon(≈1.12eV)
g
f Low-passcut-offfrequencyofanamplifier
c
f Cornerfrequencyofthe1/fnoise
c,1/f
f Choppingclockfrequency
chop
f OperatingfrequencyoftheCSFstage
CSF
f Low-passcut-offfrequencyoftheIA
LP,IA
g OutputtransconductanceofaMOStransistor
ds
g TransconductanceofaMOStransistor
m
g Outputtransconductanceofacurrentsource
o
I Displacementcurrentthroughhumanbody
D
I DraincurrentofaMOStransistor
ds
I Totalsupplycurrent
tot
k Boltzmannconstant=1.3806×10–23m2kg/s2
KF 1/fnoiseconstantofaMOStransistor(C2/cm2)
F
μ MobilityofpMOStransistors
p
n Weakinversionslopefactor(=1.45inAMIS0.5µmtechnology)
q Unitcharge=1.6×10–19C
R Drain-to-sourceresistanceofaMOStransistor
ds
R Electrodeimpedance
el
R Sourceresistance
s
S Thermalnoiselevelofanamplifier
0
T AbsolutetemperatureinKelvin
V Common-modevoltageonthehumanbody
CM
V MaximumdifferentialDCelectrodeoffsetvoltagethatcanbe
elec-off,max
filteredbyACCIA
V Gate-to-sourcevoltageofanMOStransistor
gs
V Input-referredtotalRMSvoltagenoise
in,rms
V Source-to-gatevoltageofapMOStransistor
sg
V Source-to-drainvoltageofapMOStransistor
sd
V ThermalvoltagekT/q
t
xiii