Yoo / Hoof Bio-Medical CMOS ICs

1. Auflage 2010
ISBN: 978-1-4419-6597-4
Verlag: Springer-Verlag
Format: PDF
Kopierschutz: Adobe DRM (»Systemvoraussetzungen)

E-Book, Englisch, 526 Seiten

This book is based on a graduate course entitled, Ubiquitous Healthcare Circuits and Systems, that was given by one of the editors at his university.  It includes an introduction and overview to the field of biomedical ICs and provides information on the current trends in research.  The material focuses on the design of biomedical ICs rather than focusing on how to use prepared ICs.

Autoren/Hrsg.

Yoo, Hoi-Jun

Hoof, Chris

Inhaltsverzeichnis

1;Preface;5
2;Contents;7
3;Contributors;9
4;1 Introduction to Bio-Medical CMOS IC;11
4.1;1.1 Introduction to Bio-Medical CMOSIC;11
4.2;1.2 Architecture of Sensor Systems with Bio-medical CMOS IC;13
4.3;1.3 Applications and Future Trends;16
4.4;1.4 Organization of the Book;18
4.5;References;19
5;Part I Vital Signal Sensing and Processing;20
5.1;2 Introduction to Bioelectricity;21
5.1.1;2.1 Introduction;21
5.1.2;2.2 Electrical Properties of the Human body;22
5.1.2.1;2.2.1 Cell Membrane;22
5.1.2.2;2.2.2 Membrane Potential;23
5.1.2.3;2.2.3 Equivalent Circuit Model for the Plasma Membrane;25
5.1.2.4;2.2.4 Graded Response of Membrane Potential;26
5.1.2.5;2.2.5 Action Potential;28
5.1.2.6;2.2.6 Synaptic Transmission;29
5.1.3;2.3 Equivalent Circuit Model of Tissues and Organs;31
5.1.4;2.4 Biomedical Devices;32
5.1.4.1;2.4.1 Electrocardiography;32
5.1.4.2;2.4.2 Electroencephalography;33
5.1.4.3;2.4.3 Electromyography;35
5.1.5;2.5 Current Research Trends in Biomedical Electrical Instruments;36
5.1.6;References;37
5.2;3 Biomedical Electrodes For Biopotential Monitoring and Electrostimulation;38
5.2.1;3.1 Introduction;38
5.2.2;3.2 Electrical Properties of Electrode-Skin Interface;41
5.2.2.1;3.2.1 The Electrode-Electrolyte Interface;41
5.2.2.1.1;3.2.1.1 The Electrode-Electrolyte Potential;41
5.2.2.1.2;3.2.1.2 The Electrode-Electrolyte Impedance;44
5.2.2.1.3;3.2.1.3 Complex Impedance Plot;46
5.2.2.1.4;3.2.1.4 Bode Plot;47
5.2.2.1.5;3.2.1.5 Polarization;49
5.2.2.1.6;3.2.1.6 Transient Response and Tissue Damage;51
5.2.2.1.7;3.2.1.7 Limit Voltages and Currents of Linearity;56
5.2.2.1.8;3.2.1.8 Electrode Metals;58
5.2.2.2;3.2.2 The Skin;61
5.2.2.2.1;3.2.2.1 Structure of the Skin;61
5.2.2.2.2;3.2.2.2 Electrical Properties of the Skin;62
5.2.2.2.3;3.2.2.3 The Skin's Parallel Capacitance, CSP ;64
5.2.2.2.4;3.2.2.4 The Skin's Parallel Resistance, RSP ;64
5.2.3;3.3 Electrode Design;73
5.2.3.1;3.3.1 External Biosignal Monitoring Electrodes;73
5.2.3.1.1;3.3.1.1 Historical Background;73
5.2.4;3.4 Modern Disposable Electrodes;78
5.2.5;3.5 Solid Conductive Adhesive Electrodes;81
5.2.6;3.6 Wearable Electrodes for Personalized Health;83
5.2.6.1;3.6.1 External Electrostimulation Electrodes;85
5.2.6.1.1;3.6.1.1 Historical Background;85
5.2.6.1.2;3.6.1.2 Current Density Considerations;89
5.2.6.1.3;3.6.1.3 Modern Electrode Designs;91
5.2.7;3.7 Implant Electrodes;98
5.2.7.1;3.7.1 Historical Background;99
5.2.7.2;3.7.2 Some Modern Electrode Designs;103
5.2.7.3;3.7.3 Microelectrodes;108
5.2.8;3.8 Electrode Standards;114
5.2.8.1;3.8.1 Standards for Biosignal Monitoring Electrodes;114
5.2.8.1.1;3.8.1.1 Standards for Disposable ECG electrodes. ANSI/AAMI EC 12 (2000);114
5.2.8.2;3.8.2 Standards for Stimulation Electrodes;120
5.2.8.2.1;3.8.2.1 Standards for Automatic External Defibrillators and Remote-Control Defibrillators. ANSI/AAMI DF 80 (2003);120
5.2.8.2.2;3.8.2.2 Standards for Electrosurgical Devices. ANSI/AAMI HF 18 (2001);122
5.2.9;3.9 Summary;124
5.2.10;References;125
5.3;4 Readout Circuits;132
5.3.1;4.1 Introduction;132
5.3.2;4.2 Biopotential Acquisition;133
5.3.2.1;4.2.1 Biopotential Signals;133
5.3.2.2;4.2.2 Biopotential Electrodes;134
5.3.2.3;4.2.3 Interference Theory;136
5.3.2.4;4.2.4 Noise Considerations;138
5.3.3;4.3 How Application Affects the Choice of Instrumentation Amplifier Topology;139
5.3.4;4.4 Power Efficient Instrumentation Amplifier Topologies for Biopotential Signal Extraction;142
5.3.4.1;4.4.1 Limitations of Existing Off-the-shelf Instrumentation Amplifier Topologies;142
5.3.4.2;4.4.2 Instrumentation Amplifiers Utilizing Pseudo Resistors;144
5.3.4.3;4.4.3 Introduction to Chopper Modulation;146
5.3.4.4;4.4.4 Chopper Modulating Amplifiers for Biopotential Signal Extraction;149
5.3.4.5;4.4.5 Summary and Comparison of Topologies;151
5.3.5;4.5 Current Mode Instrumentation Amplifiers;154
5.3.5.1;4.5.1 Open-Loop Current Mode Instrumentation Amplifiers;154
5.3.5.2;4.5.2 Closed-Loop Current Mode Instrumentation Amplifiers (Current Balancing/Feedback Instrumentation Amplifiers);155
5.3.5.3;4.5.3 Chopper Modulated Current Balancing Instrumentation Amplifiers;157
5.3.6;4.6 Examples of ICs for Biopotential Acquisition;158
5.3.7;4.7 Conclusion;160
5.3.8;References;160
5.4;5 Low-Power ADCs for Bio-Medical Applications;163
5.4.1;5.1 ADC Specifications;164
5.4.1.1;5.1.1 Ideal ADC Specifications;164
5.4.1.2;5.1.2 Practical ADC Specifications;165
5.4.1.3;5.1.3 ADC Implementation Issues;167
5.4.2;5.2 Charge-Sharing Successive Approximation ADCs;167
5.4.2.1;5.2.1 Basic Operation Principle;169
5.4.2.1.1;5.2.1.1 Input Sampling;169
5.4.2.1.2;5.2.1.2 Successive Approximation, MSB;170
5.4.2.1.3;5.2.1.3 Successive Approximation, MSB-1;171
5.4.2.1.4;5.2.1.4 Successive Approximation, Remaining Bits;171
5.4.2.1.5;5.2.1.5 First Block Diagram;172
5.4.2.2;5.2.2 Asynchronous Operation;173
5.4.2.3;5.2.3 Binary Scaled Capacitor Array;174
5.4.2.4;5.2.4 Comparator Noise;175
5.4.2.4.1;5.2.4.1 Comparator Offset;177
5.4.2.5;5.2.5 Implementation;177
5.4.3;5.3 Comparator-Based Asynchronous Binary Search ADCs;178
5.4.3.1;5.3.1 Operating Principle;179
5.4.3.2;5.3.2 Implemented Two-Step 1-b Coarse 6-b Fine Architecture;181
5.4.3.2.1;5.3.2.1 Clock Generation and A/D-Converter Timing;182
5.4.3.2.2;5.3.2.2 Dynamic Comparator with Embedded Threshold and Encoding;182
5.4.3.2.3;5.3.2.3 Passive Track-and-Hold;184
5.4.3.2.4;5.3.2.4 Feedback D/A Converter;186
5.4.3.2.5;5.3.2.5 Calibration;187
5.4.3.2.6;5.3.2.6 Power Breakdown;188
5.4.3.3;5.3.3 Experimental Results;188
5.4.3.3.1;5.3.3.1 Layout Implementation;188
5.4.3.3.2;5.3.3.2 Measurement Setup;190
5.4.3.3.3;5.3.3.3 Measurement Results;190
5.4.3.3.4;5.3.3.4 Sensitivity to Environmental Parameters;193
5.4.3.3.5;5.3.3.5 Energy Efficiency;193
5.4.3.4;5.3.4 Summary;195
5.4.4;5.4 Conclusions;195
5.4.5;References;195
5.5;6 Low Power Bio-Medical DSP;197
5.5.1;6.1 Introduction;197
5.5.2;6.2 ECG Signal Processor Design;198
5.5.2.1;6.2.1 Algorithm Overview;198
5.5.2.2;6.2.2 Hardware Implementation;199
5.5.3;6.3 Pre Processing;200
5.5.3.1;6.3.1 Filtering;201
5.5.3.2;6.3.2 Feature Extraction;201
5.5.3.3;6.3.3 ECG Skeleton;204
5.5.3.4;6.3.4 Segmentation Memory;208
5.5.4;6.4 Classification Processing;208
5.5.4.1;6.4.1 ECG Classification Algorithm;208
5.5.4.2;6.4.2 Micro Architecture of RISC;209
5.5.5;6.5 Post-processor;212
5.5.5.1;6.5.1 Huffman Coding;212
5.5.5.2;6.5.2 AES-128;214
5.5.6;6.6 Low Energy Techniques;215
5.5.6.1;6.6.1 Heterogeneous Processor Integration;215
5.5.6.2;6.6.2 Low Supply Voltage Operation;215
5.5.6.3;6.6.3 Segmentation-Based Pipelined Operation;217
5.5.6.4;6.6.4 Clock Gating;218
5.5.6.5;6.6.5 On-Chip Memory Reduction;218
5.5.6.6;References;220
6;Part II Bio-Medical Wireless Communication;222
6.1;7 Short Distance Wireless Communications;223
6.1.1;7.1 Introduction;223
6.1.2;7.2 Biomedical Telemetry Methods;224
6.1.2.1;7.2.1 Wave Propagation;224
6.1.2.1.1;7.2.1.1 EM Wave Propagation;225
6.1.2.1.2;7.2.1.2 Acoustic Wave Propagation;228
6.1.2.2;7.2.2 Conduction;229
6.1.2.3;7.2.3 Near-Field Coupling;229
6.1.2.3.1;7.2.3.1 Capacitive Links;230
6.1.2.3.2;7.2.3.2 Inductive Links;230
6.1.2.4;7.2.4 Near-Field versus Far-Field;231
6.1.3;7.3 Modulation Methods;232
6.1.3.1;7.3.1 Analog Modulation;233
6.1.3.1.1;7.3.1.1 AM;233
6.1.3.1.2;7.3.1.2 FM and PM;235
6.1.3.1.3;7.3.1.3 Discussion on Analog Modulation Methods;239
6.1.3.2;7.3.2 Analog Pulse Modulation Encoding;239
6.1.3.2.1;7.3.2.1 Pulse Amplitude Modulation (PAM);240
6.1.3.2.2;7.3.2.2 Pulse Width/Duration Modulation (PWM or PDM);241
6.1.3.2.3;7.3.2.3 Pulse Position Modulation (PPM);241
6.1.3.2.4;7.3.2.4 Pulse Frequency Modulation (PFM);241
6.1.3.2.5;7.3.2.5 Analog Multiple Channel Modulation Methods;242
6.1.3.3;7.3.3 Digital Pulse Modulation Encoding;243
6.1.3.3.1;7.3.3.1 Pulse Code Modulation (PCM);243
6.1.3.3.2;7.3.3.2 Line Encoding;244
6.1.3.4;7.3.4 Digital Modulation;246
6.1.3.4.1;7.3.4.1 ASK;247
6.1.3.4.2;7.3.4.2 FSK;247
6.1.3.4.3;7.3.4.3 PSK;247
6.1.3.4.4;7.3.4.4 Digital Multiple Channel Transmission;248
6.1.3.5;7.3.5 Analog or Digital Modulation?;251
6.1.3.6;7.3.6 Data Rates;251
6.1.4;7.4 Compression;252
6.1.4.1;7.4.1 Loss-Less Compression Algorithms;253
6.1.4.2;7.4.2 Lossy Compression Algorithms;254
6.1.5;7.5 Error Correction;255
6.1.5.1;7.5.1 Block Codes;256
6.1.5.2;7.5.2 Convolutional Codes;257
6.1.6;7.6 Carrier Frequency Selection for RF Links;257
6.1.6.1;7.6.1 Tissue Absorption vs. Antenna Size;257
6.1.6.2;7.6.2 Antenna Size vs. Bandwidth Requirements;260
6.1.6.3;7.6.3 Regulations vs. Bandwidth Requirements;262
6.1.7;7.7 Biomedical Telemetry Applications;263
6.1.7.1;7.7.1 Physiological Monitoring;263
6.1.7.1.1;7.7.1.1 Bladder Pressure Monitoring;263
6.1.7.1.2;7.7.1.2 Wireless ECG Monitoring Integrated in Textile;263
6.1.7.1.3;7.7.1.3 Textile Integrated Breathing and ECG Monitoring System;265
6.1.7.1.4;7.7.1.4 Pacemaker Monitoring and Programming;265
6.1.7.1.5;7.7.1.5 Inductive Power and Data Transmission for Wireless Endoscopy;267
6.1.7.1.6;7.7.1.6 Wireless Capsule Endoscopy: Given Imaging Pillcam;267
6.1.7.2;7.7.2 Orthopedic Implant Monitoring and Control;267
6.1.7.2.1;7.7.2.1 Distraction Nail Driver;267
6.1.7.2.2;7.7.2.2 Hip Prosthesis Fixation Analysis;268
6.1.7.2.3;7.7.2.3 Telemetry IC Design for Orthopedic Monitoring;270
6.1.7.3;7.7.3 Nerve Implant Monitoring and Stimulation;272
6.1.7.3.1;7.7.3.1 Cochlear Implants;272
6.1.7.3.2;7.7.3.2 Retinal Prosthesis;273
6.1.7.4;7.7.4 General Monitoring and Identification;273
6.1.7.4.1;7.7.4.1 RFID;273
6.1.7.4.2;7.7.4.2 Portable Heart Rate Monitoring;273
6.1.7.5;7.7.5 Overview of Commercial Biomedical Transmitters;274
6.1.7.5.1;7.7.5.1 Zarlink ZL70101;274
6.1.7.5.2;7.7.5.2 Zarlink ZL70250;276
6.1.7.5.3;7.7.5.3 Nordic NR24L01+;276
6.1.7.5.4;7.7.5.4 Other Manufacturers;276
6.1.7.5.5;References;276
6.2;8 Bio-Medical Application of WBAN: Trends and Examples;282
6.2.1;8.1 The New Wave of Healthcare Systems;282
6.2.2;8.2 An Enabling Technology: Body Area Networks;283
6.2.3;8.3 Ambulatory Cardiac Monitoring;285
6.2.3.1;8.3.1 Trends;285
6.2.3.2;8.3.2 Snapshot on the State-of-the-Art;287
6.2.3.3;8.3.3 Detailed View on IMEC Low-Power Ambulatory ECG Prototypes;289
6.2.4;8.4 Wireless Sleep Monitoring;292
6.2.4.1;8.4.1 Trends;292
6.2.4.2;8.4.2 Snapshot on the State-of-the-Art;293
6.2.4.3;8.4.3 Detailed View on IMEC Wireless Sleep Staging Prototype;294
6.2.5;8.5 Mental Health and Emotion Monitoring;296
6.2.5.1;8.5.1 Trends;296
6.2.5.2;8.5.2 Snapshot on the State-of-the-Art;296
6.2.5.3;8.5.3 Detailed View on IMEC Wireless ANS Monitoring Prototype;297
6.2.6;8.6 Remaining Challenges;301
6.2.6.1;8.6.1 Ultra-Low-Power Technologies;301
6.2.6.2;8.6.2 Increasing Functionality;301
6.2.6.3;8.6.3 Autonomous Systems;302
6.2.6.4;8.6.4 Multi-Parameter Sensors;302
6.2.6.5;8.6.5 Dry Electrodes;302
6.2.6.6;8.6.6 Integration and Packaging Technology;303
6.2.7;8.7 Conclusions;303
6.2.8;References;304
6.3;9 Body Channel Communication for Energy-Efficient BAN;306
6.3.1;9.1 Introduction;306
6.3.1.1;9.1.1 Motivation;306
6.3.1.2;9.1.2 Human Body Communications;307
6.3.2;9.2 Channel Characteristics;308
6.3.3;9.3 Design of Wideband Signaling Communication Link;311
6.3.4;9.4 Wideband Signaling Transceiver;317
6.3.4.1;9.4.1 WBS Receiver AFE;322
6.3.4.2;9.4.2 All-Digital Quadratic Sampling CDR Circuit;325
6.3.4.3;9.4.3 Direct Digital Transmitter;327
6.3.5;9.5 Measurement Results;329
6.3.5.1;9.5.1 WBS Receiver AFE;329
6.3.5.2;9.5.2 WBS Transceiver;330
6.3.6;9.6 System Operation Demonstration;334
6.3.6.1;9.6.1 Introduction;334
6.3.6.2;9.6.2 Related Works;335
6.3.6.3;9.6.3 Design Architecture;335
6.3.6.4;9.6.4 Realization;336
6.3.6.4.1;9.6.4.1 Summary;338
6.3.7;9.7 Conclusion;338
6.3.8;References;338
7;Part III Examples of Bio-Medical ICs;340
7.1;10 Wearable Healthcare System;341
7.1.1;10.1 Introduction;341
7.1.1.1;10.1.1 Issues on Continuous Wearable Healthcare Using BSNs;342
7.1.1.2;10.1.2 Snapshots of Previous Works in Health Monitoring;343
7.1.1.3;10.1.3 An Example Wearable Healthcare System;345
7.1.2;10.2 Reliable and Low Cost BSN for Wearable Healthcare;345
7.1.2.1;10.2.1 Self-Configured Wearable BSN;345
7.1.2.2;10.2.2 Adaptive Power Transmission;348
7.1.2.3;10.2.3 Network Controller SoC;349
7.1.2.4;10.2.4 Summary;351
7.1.3;10.3 Fabric Circuit Board;351
7.1.3.1;10.3.1 Introduction;351
7.1.3.2;10.3.2 Dry Electrodes by P-FCB;352
7.1.3.2.1;10.3.2.1 Electrode Impedance;353
7.1.3.2.2;10.3.2.2 Impedance Versus Frequency;353
7.1.3.2.3;10.3.2.3 Impedance Over Time;353
7.1.3.3;10.3.3 Inductors by P-FCB;354
7.1.3.4;10.3.4 Summary;355
7.1.4;10.4 Wirelessly Powered Sensor;356
7.1.4.1;10.4.1 Introduction;356
7.1.4.2;10.4.2 Form Factor;356
7.1.4.3;10.4.3 Sensor Design;357
7.1.4.4;10.4.4 Wireless Power Transmission;358
7.1.4.4.1;10.4.4.1 Conventional Rectifier;359
7.1.4.4.2;10.4.4.2 Adaptive Threshold Rectifier (ATR);360
7.1.4.5;10.4.5 Sensor Readout Front-End;361
7.1.4.6;10.4.6 Implementation;364
7.1.4.7;10.4.7 Summary;365
7.1.5;10.5 System Implementation;366
7.1.5.1;10.5.1 Wirelessly Powered Adhesive Bandage Sensor;366
7.1.5.2;10.5.2 Health Monitoring Chest Band;366
7.1.6;10.6 Conclusion;367
7.1.7;References;370
7.2;11 Digital Hearing Aid and Cochlear Implant;373
7.2.1;11.1 Introduction of the Digital Hearing Aid;373
7.2.1.1;11.1.1 Population Trends of the Hearing Aids;373
7.2.1.2;11.1.2 Future of the Hearing Aids;374
7.2.2;11.2 Conventional Digital Hearing Aids;375
7.2.2.1;11.2.1 Types of the Digital Hearing Aids;375
7.2.2.2;11.2.2 Design Issues of the Digital Hearing Aids;376
7.2.3;11.3 An Adaptive Digital Hearing Aid Chip with On Chip Human Factors Consideration;376
7.2.3.1;11.3.1 Introduction;376
7.2.3.2;11.3.2 An Internal Gain Verification Algorithm;378
7.2.3.2.1;11.3.2.1 Conventional Gain Verification Method;378
7.2.3.2.2;11.3.2.2 Autonomous Gain Verification Algorithm;379
7.2.3.2.3;11.3.2.3 Simulation Results;384
7.2.3.3;11.3.3 A Multi Mode Audio Processor;386
7.2.3.3.1;11.3.3.1 Hearing Aid Mode Operation;387
7.2.3.3.2;11.3.3.2 Smart Earphone Mode Operation;387
7.2.3.3.3;11.3.3.3 Direction Perception Mode Operation;388
7.2.3.4;11.3.4 Low Power Analog Front-End;389
7.2.3.4.1;11.3.4.1 System Design Considerations;389
7.2.3.4.2;11.3.4.2 Overall Architecture of the Analog Front-End;390
7.2.3.4.3;11.3.4.3 Adaptive Analog Front-End Design;391
7.2.3.4.4;11.3.4.4 Building Block Circuits Design;396
7.2.3.5;11.3.5 Low Power Digital Back-End;399
7.2.3.5.1;11.3.5.1 16 Channel IFIR DSP;399
7.2.3.5.2;11.3.5.2 Heterogeneous DAC;404
7.2.3.5.3;11.3.5.3 H-bridge as a Speaker Driver;406
7.2.3.6;11.3.6 Implementation and Measurement Results;406
7.2.3.7;11.3.7 Conclusions;412
7.2.4;11.4 Cochlear Implant;415
7.2.4.1;11.4.1 Introduction of the Cochlear Implant;415
7.2.4.2;11.4.2 Design of the Cochlear Implant;417
7.2.4.3;11.4.3 Future of the Cochlear Implant;419
7.2.4.4;References;419
7.3;12 Cardiac Rhythm Management ICs;422
7.3.1;12.1 Introduction;422
7.3.1.1;12.1.1 Anatomy of the Heart;422
7.3.1.2;12.1.2 Pacemakers;424
7.3.1.3;12.1.3 Implantable Cardioverter Defibrillators;424
7.3.2;12.2 Components of Pacemaker and ICD;425
7.3.2.1;12.2.1 Leads;425
7.3.2.2;12.2.2 Device Programmer;427
7.3.2.3;12.2.3 Device Subsystems;428
7.3.2.4;12.2.4 Case, Feedthrough and Header;428
7.3.2.5;12.2.5 Battery;429
7.3.2.6;12.2.6 ICD Capacitors;431
7.3.3;12.3 Electronics;432
7.3.3.1;12.3.1 Basic Pacemaker Functions;432
7.3.3.2;12.3.2 Sensing Circuits;433
7.3.3.3;12.3.3 ADC;434
7.3.3.4;12.3.4 Pace Driver and Mux;435
7.3.3.5;12.3.5 MCU;439
7.3.3.6;12.3.6 Sensor I/O;440
7.3.3.7;12.3.7 Telemetry;441
7.3.3.8;12.3.8 Clock Generator and Power Management;443
7.3.4;12.4 Basic ICD Functions;444
7.3.5;12.5 IC Process Technology;446
7.3.5.1;12.5.1 Process Technology;447
7.3.5.2;12.5.2 Low Power Design Techniques;448
7.3.6;12.6 Future Trends;450
7.3.7;References;451
7.4;13 Neurostimulation Design from an Energy and Information Transfer Perspective;453
7.4.1;13.1 Introduction;453
7.4.2;13.2 Overview of Challenges and System Requirements;454
7.4.3;13.3 Completing the Energy Transfer Circuit: From Battery to Body;456
7.4.3.1;13.3.1 Secondary Cell Recharge;457
7.4.3.2;13.3.2 Energy Source Characteristics;459
7.4.3.3;13.3.3 Boosting the Voltage---Providing Overhead for the Stimulation Engine;460
7.4.3.4;13.3.4 Generating the Stimulation Signal;463
7.4.3.4.1;13.3.4.1 Reference Current Generator;466
7.4.3.4.2;13.3.4.2 Active Sources and Sinks;466
7.4.3.4.3;13.3.4.3 Scaling Considerations for Electrode Sinks and Sources;468
7.4.3.4.4;13.3.4.4 Output Regulation with a Reference Resistor;469
7.4.3.4.5;13.3.4.5 Fractional Current Regulation Through Electrodes;471
7.4.3.4.6;13.3.4.6 Tying It All Together: A Complete Stimulation Engine;472
7.4.4;13.4 The Tissue Interface and General Safety Considerations;473
7.4.5;13.5 Future Directions and Trends;476
7.4.5.1;13.5.1 Closed-Loop, Adaptive Stimulation;476
7.4.5.2;13.5.2 Optogenetic Neuromodulation;477
7.4.6;13.6 Conclusion;479
7.4.7;References;479
7.5;14 Artificial Retina IC;481
7.5.1;14.1 Introduction;481
7.5.2;14.2 Fundamentals for Artificial Retina;482
7.5.2.1;14.2.1 Retina and Blindness;482
7.5.2.2;14.2.2 Principle of Artificial Retina;482
7.5.2.3;14.2.3 Classification of Artificial Retina;484
7.5.2.3.1;14.2.3.1 Extraocular Artificial Retina;484
7.5.2.3.2;14.2.3.2 Intraocular Artificial Retina;484
7.5.2.4;14.2.4 Artificial Retina System;485
7.5.3;14.3 Basic Circuits for Artificial Retina;487
7.5.3.1;14.3.1 Stimulation of Retinal Cells;488
7.5.3.2;14.3.2 Stimulator;488
7.5.3.2.1;14.3.2.1 Charge Balance;490
7.5.3.3;14.3.3 Photosensor;491
7.5.3.3.1;14.3.3.1 Photodiode;492
7.5.3.4;14.3.4 Photosensor Array in Artificial Retina IC;494
7.5.3.4.1;14.3.4.1 Micro PD Array;495
7.5.3.4.2;14.3.4.2 Active Pixel Sensor;496
7.5.3.4.3;14.3.4.3 Log Sensor;498
7.5.3.4.4;14.3.4.4 Photosensor Based on Pulse Frequency Modulation;500
7.5.3.5;14.3.5 Power and Data Transmission;504
7.5.4;14.4 Case studies: Artificial retina Device for over 1000 Electrodes;505
7.5.4.1;14.4.1 Multiple Microchip Architecture;505
7.5.4.1.1;14.4.1.1 Microchip Specification;506
7.5.4.1.2;14.4.1.2 Stimulator Specificaton;507
7.5.4.1.3;14.4.1.3 In vivo experiment;508
7.5.4.2;14.4.2 Multiple Microchip-Based Retinal Stimulator with Light-Controlled Function;510
7.5.4.3;References;511
8;Index;515