Table Of ContentAnalog IC Design Techniques
for Nanopower Biomedical
Signal Processing
RIVER PUBLISHERS SERIES IN BIOMEDICAL
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Volume1
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The NEC and You Perfect Together:
Analog IC Design Techniques
A ComprehfoenrsNivaen Sotpudoyw oef rthBei omedical
National Electrical Code
Signal Processing
Chutham Sawigun
Gregory P. Bierals
MahanakornUniversityofTechnology
Electrical Design Institute, USA Thailand
WouterA. Serdijn
DelftUniversityofTechnology
TheNetherlands
River Publishers
Published2016byRiverPublishers
RiverPublishers
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Analog IC Design Techniques for Nanopower Biomedical Signal Processing/by Chutham Sawigun, Chutham
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Contents
Preface xi
ListofFigures xiii
ListofTables xix
1 Introduction 1
1.1 Motivations . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1.1 UnderstandingtheHumanNervousSystem . . . . . 1
1.1.2 ParadigmShiftinBio-Medicine . . . . . . . . . . . 2
1.2 AnalogSignalProcessinginWearable
andImplantableDevices . . . . . . . . . . . . . . . . . . . 3
1.3 NanopowerCMOSICDesignChallenges . . . . . . . . . . 4
1.4 MaterialsandMethods . . . . . . . . . . . . . . . . . . . . 5
1.5 ThesisOrganization . . . . . . . . . . . . . . . . . . . . . . 6
2 ReviewofRelevantTechniquesandMOSFETModel 9
2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.2 Switched-CurrentTechnique . . . . . . . . . . . . . . . . . 9
2.2.1 1st and2nd-GenerationSIMemoryCells . . . . . . . 9
2.2.2 SwitchingErrorCancellationinaSIMemoryCells. . 10
2.3 Gm –C Filters . . . . . . . . . . . . . . . . . . . . . . . . 13
2.3.1 BasicConceptandDesignConsiderations . . . . . . 13
2.3.2 Power-EfficientG –CFilters . . . . . . . . . . . . 14
m
2.4 TranslinearCircuits . . . . . . . . . . . . . . . . . . . . . . 15
2.4.1 TLPrinciple . . . . . . . . . . . . . . . . . . . . . 15
2.4.2 ExponentialandsinhTransconductors . . . . . . . . 16
2.4.3 Current-ModeAnalogMultiplier . . . . . . . . . . . 18
2.5 EKVMOSModelforLow-CurrentAnalogDesign . . . . . 19
2.5.1 Large-SignalEquations . . . . . . . . . . . . . . . . 19
2.5.2 Small-SignalModel . . . . . . . . . . . . . . . . . 21
2.6 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . 22
v
vi Contents
PartI: AnalogSampled-DataCircuitTechnique
3 Switched-CurrentTechniqueinSubthresholdCMOS 25
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 25
3.2 FeedbackAnalysisofa2nd-GenerationSIMemoryCell . . . 26
3.2.1 Reexaminationofa2nd-GenerationSI
MemoryCell . . . . . . . . . . . . . . . . . . . . . 26
3.2.2 ReconsiderationofthePerformanceEnhancement
Techniques . . . . . . . . . . . . . . . . . . . . . . 27
3.2.3 StabilityandTransientBehavior . . . . . . . . . . . 30
3.3 DesignConsideration:Class-AandClass-AB . . . . . . . . 32
3.3.1 CurrentConsumption . . . . . . . . . . . . . . . . . 33
3.3.2 SignalExcursionandDrivability . . . . . . . . . . . 34
3.3.3 Noise . . . . . . . . . . . . . . . . . . . . . . . . . 36
3.3.4 EffectsofTransistorMismatch,InputCurrent
ImbalanceandSwitchingErrorCancellation . . . . 38
3.3.5 SupplyNoiseRejection . . . . . . . . . . . . . . . 41
3.4 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . 41
4 AClass-ABCurrent-ModeSubthresholdSHCircuit 43
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 43
4.2 DesignofaClass-ABCSHCircuit . . . . . . . . . . . . . . 43
4.2.1 BiasCondition . . . . . . . . . . . . . . . . . . . . 44
4.2.2 InputCurrentLimitationandSettlingBehavior . . . 45
4.3 CircuitSimulations . . . . . . . . . . . . . . . . . . . . . . 46
4.4 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . 54
PartII: CompactContinuous-TimeFilters
5 NanopowerBPFUsingSingle-BranchBiquads 57
5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 57
5.2 SingleBranchFilters . . . . . . . . . . . . . . . . . . . . . 60
5.2.1 FilterTopologyUsingFeedback
Transconductors . . . . . . . . . . . . . . . . . . . 60
5.2.2 SupplyVoltageRequirement
andCurrentConsumption . . . . . . . . . . . . . . 62
5.2.3 Noise . . . . . . . . . . . . . . . . . . . . . . . . . 64
5.3 CascadedBandpassFilter . . . . . . . . . . . . . . . . . . . 66
5.3.1 FilterTopologyConsiderations . . . . . . . . . . . . 66
Contents vii
5.3.2 TransistorLevelRealization . . . . . . . . . . . . . 67
5.3.3 DynamicRange . . . . . . . . . . . . . . . . . . . . 68
5.3.4 Common-ModeBehavior . . . . . . . . . . . . . . 70
5.4 DesignMethodology . . . . . . . . . . . . . . . . . . . . . 70
5.4.1 FilterOrder . . . . . . . . . . . . . . . . . . . . . . 70
5.4.2 MidbandGainandDynamicRange . . . . . . . . . 71
5.4.3 CenterFrequency,BiasCurrentandTuning . . . . . 71
5.4.4 TransistorDimensions . . . . . . . . . . . . . . . . 73
5.5 MeasurementResults . . . . . . . . . . . . . . . . . . . . . 73
5.6 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . 82
6 Follower-Integrator-basedLPFforECGDetection 83
6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 83
6.2 ECGDetectorLPFDesign . . . . . . . . . . . . . . . . . . 84
6.3 Follower-Integrator-basedLowpassFilter . . . . . . . . . . 86
6.3.1 Concept . . . . . . . . . . . . . . . . . . . . . . . . 86
6.3.2 Transistor-LevelConsideration . . . . . . . . . . . . 87
6.4 ECGLowpassFilterDesign . . . . . . . . . . . . . . . . . 90
6.4.1 FilterTopology . . . . . . . . . . . . . . . . . . . . 90
6.4.2 SupplyVoltageRequirement,SignalSwing
andTuning . . . . . . . . . . . . . . . . . . . . . . 92
6.4.3 Signal-to-NoiseRatio . . . . . . . . . . . . . . . . 93
6.4.4 SupplyNoiseRejectionandStability . . . . . . . . 94
6.5 DesignProcedure . . . . . . . . . . . . . . . . . . . . . . . 94
6.5.1 DynamicRange . . . . . . . . . . . . . . . . . . . . 94
6.5.2 CutoffFrequency,BiasCurrentandPower
Consumption . . . . . . . . . . . . . . . . . . . . . 95
6.5.3 Tuning . . . . . . . . . . . . . . . . . . . . . . . . 95
6.5.4 TransistorDimensions . . . . . . . . . . . . . . . . 95
6.6 MeasurementResults . . . . . . . . . . . . . . . . . . . . . 96
6.7 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . 104
PartIII: VeryLow-FrequencyFilteringand
Large-SwingMultiplication
7 TransconductanceReductionTechniqueforVLFFilters 107
7.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 107
7.2 ReviewofTransconductanceReductionTechniques . . . . . 108
7.3 Wide-LinearRangeLow-Gm Transconductor . . . . . . . . 109
viii Contents
7.3.1 Concept . . . . . . . . . . . . . . . . . . . . . . . . 110
7.3.2 NoiseandDynamicRange . . . . . . . . . . . . . . 111
7.3.3 CurrentConsumptionandCircuitComplexity . . . . 113
7.4 FilterDesignanditsMeasuredResults . . . . . . . . . . . . 113
7.4.1 Butterworth2nd-orderLPF . . . . . . . . . . . . . . 113
7.4.2 SupplyVoltageRequirementandSignalSwing . . . 113
7.4.3 DesignProcedure . . . . . . . . . . . . . . . . . . . 115
7.4.3.1 Passbandgain . . . . . . . . . . . . . . . 115
7.4.3.2 Minimumbiascurrentandnumber
ofstages . . . . . . . . . . . . . . . . . . 115
7.4.3.3 RecoveringDR . . . . . . . . . . . . . . 116
7.4.3.4 Biascircuit . . . . . . . . . . . . . . . . . 116
7.4.4 MeasurementResults . . . . . . . . . . . . . . . . . 116
7.5 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . 122
8 Large-SwingCurrentMultiplierforAPDetection 123
8.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 123
8.2 Class-ABCurrentMultiplier . . . . . . . . . . . . . . . . . 125
8.3 SubthresholdClass-ABBuildingBlocks . . . . . . . . . . . 127
8.4 Simulations . . . . . . . . . . . . . . . . . . . . . . . . . . 129
8.5 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . 131
9 ConclusionsandFutureWork 133
9.1 GeneralConclusions . . . . . . . . . . . . . . . . . . . . . 133
9.2 ListofAchievements . . . . . . . . . . . . . . . . . . . . . 135
9.3 FutureWork . . . . . . . . . . . . . . . . . . . . . . . . . 136
AppendixA Phase-LockedPeak-PickingSpeechProcessor 137
A.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 137
A.2 SpeechProcessinginCochlearImplants . . . . . . . . . . . 138
A.3 ReviewandComparisonofExistingProcessing
Strategies . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
A.3.1 ContinuousInterleavedSampling . . . . . . . . . . 140
A.3.2 Zero-CrossingDetection . . . . . . . . . . . . . . . 140
A.3.3 Peak-PickingTechnique . . . . . . . . . . . . . . . 140
A.3.4 Race-to-SpikeAsynchronousInterleaved
Sampling . . . . . . . . . . . . . . . . . . . . . . . 142
A.4 SystemSimulations . . . . . . . . . . . . . . . . . . . . . . 142
A.5 Discrete-TimePeak-InstantDetector . . . . . . . . . . . . . 145
Contents ix
A.5.1 Switched-CurrentPIDConcept . . . . . . . . . . . 147
A.5.2 Switched-CurrentPIDCircuit . . . . . . . . . . . . 148
A.5.3 CircuitSimulation . . . . . . . . . . . . . . . . . . 150
A.6 DiscussionandConclusions . . . . . . . . . . . . . . . . . 153
Appendix B HarmonicDistortionCalculationforChapter3 155
B.1 ClassACSHCircuit . . . . . . . . . . . . . . . . . . . . . 155
B.2 Class-ABCSHCircuit . . . . . . . . . . . . . . . . . . . . 157
References 159
Index 171
AbouttheAuthors 175
