Preface
CHAPTER
1
Smart
Sensor Basics 1
1.1
Introduction 1
1.2
Mechanical-Electronic Transitions in Sensing 3
1.3
Nature of Sensors 4
1.4
Integration of Micromachining and Microelectronics 9
1.5
Application Example 11
1.6
Summary 13
References 13
Selected
Bibliography 14
CHAPTER
2
Micromachining 17
2.1
Introduction 17
2.2 Bulk
Micromachining 18
2.3
Wafer Bonding 20
2.3.1
Silicon-on-Silicon Bonding 20
2.3.2
Silicon-on-Glass (Anodic) Bonding 21
2.3.3
Silicon Fusion Bonding 22
2.3.4
Wafer Bonding for More Complex Structures and Adding ICs 22
2.4
Surface Micromachining 24
2.4.1
Squeeze-Film Damping 26
2.4.2
Stiction 26
2.4.3
Particulate Control 26
2.4.4
Combinations of Surface and Bulk Micromachining 27
2.5
Other Micromachining Techniques 28
2.5.1
The LIGA Process 28
2.5.2
Dry Etching Processes 29
2.5.3
Micromilling 30
2.5.4
Lasers in Micromachining 31
2.6
Combining MEMS with IC Fabrication 32
2.7
Other Micromachined Materials 34
2.7.1
Diamond as an Alternate Sensor Material 34
2.7.2
Metal Oxides and Piezoelectric Sensing 35
2.7.3
Films on Microstructures 36
2.7.4
Micromachining Metal Structures 37
2.7.5
Carbon Nanotube MEMS 38
2.8 MEMS
Foundry Services and Software Tools 38
2.9
Application Example 40
2.10
Summary 42
References 42
Selected
Bibliography 45
CHAPTER
3
The
Nature of Semiconductor Sensor Output 47
3.1
Introduction 47
3.2
Sensor Output Characteristics 47
3.2.1
Wheatstone Bridge 48
3.2.2
Piezoresistivity in Silicon 49
3.2.3
Semiconductor Sensor Definitions 51
3.2.4
Static Versus Dynamic Operation 53
3.3
Other Sensing Technologies 53
3.3.1
Capacitive Sensing 53
3.3.2
Piezoelectric Sensing 54
3.3.3
The Hall-Effect 55
3.3.4
Chemical Sensors 56
3.3.5
Improving Sensor Characteristics 56
3.4
Digital Output Sensors 57
3.4.1
Incremental Optical Encoders 57
3.4.2
Digital Techniques 59
3.5
Noise/Interference Aspects 59
3.6 Low
Power, Low Voltage Sensors 60
3.6.1
Impedance 61
3.7
Analysis of Sensitivity Improvement 61
3.7.1
Thin Diaphragm 61
3.7.2
Increase Diaphragm Area 61
3.7.3
Improve Topology 61
3.8
Application Example 62
3.9
Summary 64
References 64
CHAPTER
4
Getting
Sensor Information Into the Microcontroller 67
4.1
Introduction 67
4.2
Amplification and Signal Conditioning 68
4.2.1
Instrumentation Amplifiers 69
4.2.2
Sleep-Mode Circuitry for Reducing Power 70
4.2.3
Rail to Rail Operational Amplifiers 71
4.2.4
Switched-Capacitor Amplifier 72
4.2.5
Barometer Application Circuit 73
4.2.6 4-
to 20-mA Signal Transmitter 73
4.2.7
Schmitt Trigger 74
4.3
Separate Versus Integrated Signal Conditioning 75
4.3.1
Integrated Signal Conditioning 75
4.3.2
External Signal Conditioning 76
4.4
Digital Conversion 76
4.4.1
A/D Converters 77
4.4.2
Performance of A/D Converters 79
4.4.3
Implications of A/D Accuracy and Errors 80
4.5
On-Line Tool for Evaluating a Sensor Interface Design 81
4.6
Application Example 81
4.7
Summary 81
References 83
Selected
Bibliography 84
CHAPTER
5
Using
MCUs/DSPs to Increase Sensor IQ 85
5.1
Introduction 85
5.1.1
Other IC Technologies 85
5.1.2
Logic Requirements 86
5.2 MCU
Control 86
5.3 MCUs
for Sensor Interface 87
5.3.1
Peripherals 87
5.3.2
Memory 88
5.3.3
Input/Output 89
5.3.4
On-Board A/D Conversion 90
5.3.5
Power Saving Capability 90
5.3.6
Local Voltage or Current Regulation 92
5.4 DSP
Control 92
5.4.1
Digital Signal Controllers 93
5.4.2
Field Programmable Gate Arrays 93
5.4.3
Algorithms Versus Look-Up Tables 93
5.5
Techniques and Systems Considerations 95
5.5.1
Linearization 95
5.5.2
PWM Control 96
5.5.3
Autozero and Autorange 96
5.5.4
Diagnostics 98
5.5.5
Reducing EMC/RFI 98
5.5.6
Indirect (Computed not Sensed) Versus Direct Sensing 98
5.6
Software, Tools, and Support 99
5.6.1
Design-in Support 99
5.7
Sensor Integration 100
5.8
Application Example 101
5.9
Summary 102
References 103
CHAPTER
6
Communications for Smart Sensors 107
6.1
Introduction 107
6.2
Background and Definitions 107
6.2.1
Definitions 108
6.2.2
Background 108
6.3
Sources (Organizations) and Standards 109
6.4
Automotive Protocols 112
6.4.1
CAN Protocol 113
6.4.2
LIN Protocol 115
6.4.3
Media Oriented Systems Transport 115
6.4.4
FlexRay 116
6.4.5
Other Automotive Protocol Aspects 116
6.5
Industrial Networks 117
6.5.1
Example Industrial Protocols 117
6.6
Protocols in Other Applications 117
6.7
Protocols in Silicon 118
6.7.1
MCU with Integrated CAN 118
6.7.2
LIN Implementation 120
6.7.3
Ethernet Controller 120
6.8
Transitioning Between Protocols 120
6.9
Application Example 121
6.10
Summary 123
References 123
Additional References 124
CHAPTER
7
Control
Techniques 125
7.1
Introduction 125
7.1.1
Programmable Logic Controllers 125
7.1.2
Open- Versus Closed-Loop Systems 126
7.1.3
PID Control 126
7.2
State Machines 128
7.3
Fuzzy Logic 129
7.4
Neural Networks 132
7.5
Combined Fuzzy Logic and Neural Networks 134
7.6
Adaptive Control 134
7.6.1
Observers for Sensing 135
7.7
Other Control Areas 137
7.7.1
RISC Versus CISC 138
7.8
Impact of Artifi cial Intelligence 139
7.9
Application Example 141
7.10
Summary 142
References 143
CHAPTER
8
Wireless
Sensing 147
8.1
Introduction 147
8.1.1
The RF Spectrum 148
8.1.2
Spread Spectrum 149
8.2
Wireless Data and Communications 150
8.3
Wireless Sensing Networks 151
8.3.1
ZigBee 152
8.3.2
ZigBee-Like Wireless 152
8.3.3
ANT+ 152
8.3.4
6LoWPAN 153
8.3.5
Near Field Communication (NFC) 153
8.3.6
Z-Wave 153
8.3.7
Dust Networks 154
8.3.8
Other RF Wireless Solutions 154
8.3.9
Optical Signal Transmission 154
8.4
Industrial Wireless Sensing Networks 154
8.5 RF
Sensing 155
8.5.1
Surface Acoustic Wave Devices 155
8.5.2
Radar 156
8.5.3
Light Detection and Ranging (LIDAR) 157
8.5.4
Global Positioning System 158
8.5.5
Remote Emissions Sensing 159
8.5.6
Remote Keyless Entry 159
8.5.7
Intelligent Transportation System 160
8.5.8
RF-ID 162
8.5.9
Other Remote Sensing 163
8.6
Telemetry 163
8.7 RF
MEMS 166
8.8
Application Example 167
8.9
Summary 168
References 169
Selected
Bibliography 171
Understanding Smart Sensors,
3rd Edition
