Applied Embedded Electronics Design Essentials For Robust Systems
Twomey J.
Applied Embedded Electronics Design Essentials For Robust Systems - SPD 2024 - 568
Table of Contents
Preface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xix
1. Essential Concepts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Basic Electronics 1
Ideal Simplifications of Academia 4
Interconnections 4
Basic Components 9
Capacitors 9
Resistors 12
Inductors 14
Voltage Sources and Batteries 15
Current Sources 16
Switches and Relays 17
Operational Amplifiers 17
Voltage Comparators 18
Nonideal Digital Devices 19
Signal Integrity 23
Summary and Conclusions 25
Further Reading 26
2. Architecting the System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Preliminary Ideas 27
Simulate or Build 28
Through-Hole/Leaded Components (Obsolete) 28
Discrete Gate Logic (Obsolete) 28
Modern Design Strategies 29
Mostly Digital Design 31
DSP Methods: Versatility and Limits 33
vii
Digital Control Methods: DCU, MCU, MPU, FPGA, CPLD, and ASIC 35
Terminology in MCU and MPU Specifications 36
Hardware Controllers 38
Software Controllers 39
Computers Versus Controllers 40
Raspberry Pi (MPU) Versus Arduino (MCU) 40
Multipurpose and Specialty MCUs 41
Chip Set Methods 42
System Architecture Options 44
Determine Peripherals and Interconnects 49
Avoid Serial Communication Bottlenecks 54
Use Direct Memory Access for Data Transfer 55
Determine DSP Methods 55
Check for DSP Bottlenecks 57
Improve DSP Speed 59
Determine DCU Internal Features 60
Physical Package Considerations 65
Off-Chip Features and Support 66
Pulling It All Together 68
Picking a DCU Configuration and Your MCU/MPU 68
Specialized Niche Function or Feature 68
Multi-MCU Systems 69
General-Use MCU Systems 69
Picking a Specific MCU 69
Summary and Conclusions 70
Further Reading 71
3. Robust Digital Communication. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
Digital Signals, Physical Considerations, and Connections 74
Limitations of Ground-Referenced Digital Signals 74
Low-Voltage Differential Signaling 75
Organizing Interconnects for Speed and Signal Integrity 77
Lumped Versus Distributed Networks 79
Clock Distribution 86
Digital Communication: Parallel Versus Serial Ports 91
Clocking Methods for Serial Ports 91
Starting Edge Synchronization 91
Parallel Clock 92
Manchester Code Self-Clocking 92
Embedded Clock and Run Length Limited Codes 93
Digital Communication: Features and Definitions 93
Serial Data: Shared Ground, Low Speed 97
viii | Table of Contents
Universal Asynchronous Receiver Transmitter 97
Inter-Integrated Circuit and System Management Bus 98
Serial Peripheral Interface 99
Single-Wire Interfaces 101
Serial Data: Shared Ground, High Speed 101
Data Between Boards or Between Systems: Wired Methods 103
RS-232: Serial Data over Cable 103
RS-485: Differential Serial Data over Cable 105
Controller Area Network 107
Serial Data for Computer Systems 108
Universal Serial Bus 108
Serial Advanced Technology Attachment 110
Peripheral Component Interconnect Express 111
Ethernet 113
Wireless Serial Interfaces 115
WiFi 115
Bluetooth 116
Bluetooth Low Energy 117
ZigBee 118
Z-Wave 119
Adaptive Network Topology 120
Other Data Communication Methods 120
Infrared 120
Fiber-Optic Data: Go Fast, Go Far 120
JTAG: PCB Access for Test and Configuration 121
Summary and Conclusions 123
Further Reading 124
4. Power Systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
Split Phase AC Mains Power 128
AC Power Safety: Defining the Problem 129
High-Voltage and Low-Voltage Partitioning 129
Safe Failure Methods and Single Fault Safe Scenarios 130
Overcurrent Protection Methods and the Weakest Link 131
AC/DC Conversion 133
The Classic Approach: 60 Hz Transformers 133
Off-line Switchers 134
Multi-PCB Systems: The Need for Local Power Regulation 135
DC/DC Conversion: Linear Versus Switching 135
Linear Regulators: Conceptual 136
Emitter Follower Regulators Versus LDO 136
Switching Step-Down (Buck) Converter 138
Table of Contents | ix
Switching Step-Up (Boost) Converter 140
Switching Buck-Boost Converter 141
Picking Regulators and Configuring a Power System 142
Including Power Supply Monitors 146
Power Bypass, Decoupling, and Filtering 146
Radiated Noise Reduction: RC Snubbers, Ferrites, and Filters 147
Power Output Noise Reduction: Damped LPF Networks
and Cascaded Regulators 148
Power Grid Current Surges Due to Digital Logic 148
Low-Impedance Power and Ground Planes 149
Power Supply Bypass Filtering: Distributed Stabilization 150
Bypass Capacitors at High Frequencies 151
Power Bypass Capacitor Value and Distribution 153
Summary and Conclusions 156
Further Reading 157
5. Battery Power. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
Battery Basics: Definitions 160
Decision Guidelines for Rechargeable or Single-Use Batteries 164
Defining Power Requirements 165
Battery Discharge Versus Functional Voltage Range 166
Battery Types by Chemistry 167
Discharging Behavior of Batteries 171
Designing a Battery Set: Single Use and Multiple Cells 174
Designing a Rechargeable Custom Battery Pack 177
Charging Batteries 183
Smart Batteries 185
Regulations and Safety for Batteries 187
Other Energy Storage and Access Methods 188
Supercapacitors 188
Hydrogen Fuel Cells 188
Flow Batteries 190
Wireless Power 190
Solid State Batteries 192
Summary and Conclusions 193
Further Reading 194
6. Electromagnetic Interference and Electrostatic Discharge. . . . . . . . . . . . . . . . . . . . . . . 195
Preliminary Ideas 196
Intrinsic Noise 197
General Strategy Dealing with EMI 198
Regulations and Requirements 199
x | Table of Contents
Visualizations of Noise Coupling 201
Frequency Domain Analysis of EMI 203
Grounding 209
Reducing Conducted Emissions to AC Power Mains 214
Cable Interconnect Strategies 215
Reducing Noise Generation at the Source 217
Slower Clocks and Softer Transitions 217
LVDS for Digital Data to Reduce EMI 218
Spread Spectrum Clocks to Reduce EMI 219
EMI Reduction for Switched-Mode Power Supplies 219
Unintentional EMI Antennas 221
EMI Suppression on Motors 221
Reducing Noise Coupling Between On-Board Devices 222
Identifying the Big Talkers and Sensitive Listeners 223
Floor-Planning the PCB for Noise 224
Faraday Cage Methods to Contain or Protect from EMI 226
Making Circuits Less Noise Sensitive 227
Noise-Sensitive High-Impedance Nodes 227
Noise Immunity of Differential Signals 228
Noise Immunity Through Bandwidth Limiting 229
Suppressing Noise into and Out of the System: Faraday Cage Techniques 231
Electrostatic Discharge Protection 234
Summary and Conclusions 241
Further Reading 243
7. Data Converters: ADCs and DACs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245
DAC Performance Basics 246
ADC Performance Basics 251
Antialiasing Filters for ADC Inputs 254
Pulse Width Modulation DACs 255
Arbitrary Waveform Generation by Direct Digital Synthesis 260
Summary and Conclusions 261
Further Reading 262
8. Driving Peripheral Devices. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263
Switched Driver Circuits 264
High- and Low-Side Switching 264
High-Power Load Isolation 265
Drive Signal Strategies 266
Power Transistor Selection 267
Power Transistor Thermal Performance 272
Driving LEDs and Buzzers 275
Table of Contents | xi
Selection of Static Displays 278
Streaming Video Output 279
Driving Inductive Loads 280
Transient Current in a Switched Inductor 280
Driving Solenoids and Relays 282
H-Bridge Drive Circuits 283
Driving DC Motors 286
Motor Selection 286
Brushed DC Motor Driver Circuit 288
Brushless DC Motors: Single and Three Phase 288
Motors with Integrated Control Electronics 289
Stepper Motors 290
Voice Coil Motors 292
Stall Currents and Protecting from Self-Destruction 293
Audio Outputs 294
Summary and Conclusions 296
Further Reading 297
9. Sensing Peripheral Devices. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299
Sensors for Everything 300
Sensor Output Types 300
Sensor Data Capture and Calibration 302
Data Capture Method 302
Sensor Calibration 303
Sensor Response Time 303
Two-State Devices: Switches, Optical Interrupters, and Hall Sensors 304
Position and Rotation Encoders 307
Analog-Linear Sensors: A Closer Look 308
Characteristics of Analog Sensors 309
Signal Processing for Analog Sensors 311
Sensor Calibration 312
Current Sensing Methods 315
Voltage Sensing 317
Specific Sensor Applications 318
Pressure Sensors 318
Temperature Sensors 319
Strain Gauges 322
Sound and Microphones 325
Image Sensors and Video Cameras 329
Touch Panels 332
Summary and Conclusions 337
Further Reading 338
xii | Table of Contents
10. Digital Feedback Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 339
Overview of Sequence and Feedback Control 340
Digital Versus Analog Circuit Methods 342
Preliminary Definitions and Concepts 344
Transfer Functions, Block Diagrams, and Basic Feedback 345
Transient Response Terminology 347
DUC Performance Selection 349
Sequence Control 354
Select Topics in Analog Control Systems 359
Linear Systems and Approximations 361
Bode Plots for Stable Control Loops 363
Bode Plots for Gain and Phase Response 365
Bode Plots for Gain and Phase of a Control Loop 367
Bode Plots for Integral and Derivative Response 370
Bode Plots of Fixed Time Delays 371
Transition to Digital Control 372
Determine DUC Stability 373
DAC Performance Requirements 374
Accuracy of Control Math 376
ADC Performance Requirements 376
ADC Sampling Rate Determination 377
Final Selection of ADC and DAC 378
Dual-Clock Strategy for Improved Phase Margin 378
Digital Trapezoid Integration 379
Digital Integration: Limit Windup and Avoid Saturation 380
Digital Derivative by Adjacent Samples 381
Additive Time Delays in the DSP 382
PID Control Implementation 382
Response Variants: P, I, PI, and PID 385
Typical Effects of Gain Adjustments 389
Ziegler Nichols Tuning 390
Chien–Hrones–Reswick Tuning 394
Component Variance and Control Tuning 396
Adaptive Control Methods 397
Trajectory Control Methods 399
Summary and Conclusions 404
Further Reading 406
11. Schematic to PCB. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 407
PCB Terminology 408
PCB Design (EDA) Tools 411
Getting Started 411
Table of Contents | xiii
Component Selection 411
Selecting RLC Components 412
Picking Connectors for Off-Board Wires 415
Selecting IC Packages 416
Checking Component End of Life and High-Quantity Availability 417
Including Test Access and Interface Ports 417
Schematics 418
Schematic Sheets and General Organization 418
Symbol Organization for Integrated Circuits 422
Placeholders and “Do Not Populate” Components 423
Provide Generous Commentary 423
Avoid Ambiguity 424
Call Out Items Requiring Special Attention 424
Bill of Materials 425
Defining Physical, Control, and Data Layers 425
Defining a Component Footprint 426
Mechanical Definition of a PCB 428
Metric Versus Imperial Measurements 428
PCB Mounting 429
Electrical Grounding Through Mechanical Mounts 430
Drilled Hole Spacing and Keep-Outs 430
Cables to the PCB 430
PCB Alignment References 431
Conformal Coating 432
Test Fixture Using Bed of Nails 432
Defining the PCB Layer Stack-Up 432
Interplane Capacitance 438
Physical Design Rules 439
High-Voltage Spacing Rules 443
Component Placement Strategy 444
General Interconnection Methods 447
Easy Estimations of RLC Parasitics 447
Maximum Trace Currents 448
Determine Minimum Geometry Trace Requirements 449
Vias and Micro-Vias 450
Vias for Thermal Conduction 454
Specialized Interconnection Methods 455
Differential Signal Routing 455
Microstrip Transmission Lines 455
Stripline Transmission Lines 456
Differential Microstrips and Striplines 457
Kelvin Connections 457
xiv | Table of Contents
EMI and ESD Strategies 458
Solid Ground Plane for Less EMI 458
Flooded Signal Layer Grounds for Less EMI 459
ESD Interconnect 460
High-Frequency Power Bypass Methods 461
Features for Manufacture and Assembly 461
Consistent Copper Coverage 461
Panelization and Break-Apart Methods 462
Fabrication Notes 463
Manufacturing (Gerber) Files 464
Summary and Conclusions 466
Further Reading 467
12. Software and Coding. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 469
Coding Languages 470
Operating Systems 470
Picking an RTOS 471
Additional RTOS Considerations 474
Configuring Ports and Processors 475
Device Drivers 476
Problematic Portability 477
Peripheral Communication 477
Initiating Peripheral Communication 478
Device Driver Features 479
Modularity/Hierarchy for DD Code 480
Testing the DD 480
Defensive Coding Methods 480
Preprocess Data Inputs (Invalid Data) 481
Preprocess Data Inputs (Bandwidth Restrictions) 481
Preprocess Data (Human Input) 481
Background Reinitialization 482
Watchdog Timers 483
Multicontroller Coding 484
Suggestions for Well-Organized Code 485
Summary and Conclusions 487
Further Reading 488
13. Special Systems and Applications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 489
Different Electronics for Different Priorities 490
Design Priorities 490
Product Cost 490
Quality and Reliability 490
Table of Contents | xv
Power Consumption 491
Safety 491
Backward Compatibility 491
Ruggedness and User Abuse 491
Capability for Repair 492
Navigating the Regulatory Maze 492
Risk Analysis 497
Aviation Electronics (Avionics) 499
Design Priorities 499
Special Needs 499
Regulations, Certifications, and Approvals 500
Satellites and Spacecraft (Astrionics) 500
Radiation 501
Thermal Extremes 502
Vibration, Shock, and Acceleration 502
Vacuum Environments 502
Component Selection and NASA-Approved Parts 503
PCB Materials and Layout 503
Limited Life of Spacecraft 504
Regulations, Certifications, and Approvals 505
Military Electronics 506
Design Priorities and Unique Requirements 507
Regulations, Certifications, and Approvals 507
Medical Devices 509
Regulations, Certifications, and Approvals 509
Clean Functionality Throughout EMC Tests 511
Special Needs 512
Regulatory Requirements for Software and Firmware 515
Automotive 516
Typical Electronic Control Units 516
Design Priorities and Special Needs 517
Regulations, Certifications, and Approvals 518
Consumer Electronics 521
Design Priorities 521
Special Interest Groups, Technology Coalitions, and Technical Standards 522
Regulations, Certifications, and Approvals 523
Restriction of Hazardous Substances 524
Registration, Evaluation, Authorization,
and Restriction of Chemicals (REACH) 524
Industrial Automation 525
Summary and Conclusions 528
Further Reading 529
xvi | Table of Contents
14. Creating Great Products. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 531
Create Products That Solve Problems or Fulfill a Need 532
Identify the Target Market 533
Identify What the Customer Wants 533
Examine Competing Products 534
Define the Value Proposition 535
Determine Viable Pricing 535
Determine a Properly Timed Market Window 535
Establish Coalitions and Strategic Partners 536
Focus on Ease of Use 536
Determine the Needed Resources 537
Get Design Specification Consensus 537
Minimal Design and Feature Creep 537
Identify Obstacles Early 538
Get User Feedback on Prototype Builds 538
Make It Easy to Manufacture 539
Summary and Conclusions 539
Further Reading 540
Glossary of Acronyms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 541
Index. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 551
Table of Contents | xvii
9789355428820
Applied Embedded Electronics Design Essentials For Robust Systems - SPD 2024 - 568
Table of Contents
Preface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xix
1. Essential Concepts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Basic Electronics 1
Ideal Simplifications of Academia 4
Interconnections 4
Basic Components 9
Capacitors 9
Resistors 12
Inductors 14
Voltage Sources and Batteries 15
Current Sources 16
Switches and Relays 17
Operational Amplifiers 17
Voltage Comparators 18
Nonideal Digital Devices 19
Signal Integrity 23
Summary and Conclusions 25
Further Reading 26
2. Architecting the System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Preliminary Ideas 27
Simulate or Build 28
Through-Hole/Leaded Components (Obsolete) 28
Discrete Gate Logic (Obsolete) 28
Modern Design Strategies 29
Mostly Digital Design 31
DSP Methods: Versatility and Limits 33
vii
Digital Control Methods: DCU, MCU, MPU, FPGA, CPLD, and ASIC 35
Terminology in MCU and MPU Specifications 36
Hardware Controllers 38
Software Controllers 39
Computers Versus Controllers 40
Raspberry Pi (MPU) Versus Arduino (MCU) 40
Multipurpose and Specialty MCUs 41
Chip Set Methods 42
System Architecture Options 44
Determine Peripherals and Interconnects 49
Avoid Serial Communication Bottlenecks 54
Use Direct Memory Access for Data Transfer 55
Determine DSP Methods 55
Check for DSP Bottlenecks 57
Improve DSP Speed 59
Determine DCU Internal Features 60
Physical Package Considerations 65
Off-Chip Features and Support 66
Pulling It All Together 68
Picking a DCU Configuration and Your MCU/MPU 68
Specialized Niche Function or Feature 68
Multi-MCU Systems 69
General-Use MCU Systems 69
Picking a Specific MCU 69
Summary and Conclusions 70
Further Reading 71
3. Robust Digital Communication. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
Digital Signals, Physical Considerations, and Connections 74
Limitations of Ground-Referenced Digital Signals 74
Low-Voltage Differential Signaling 75
Organizing Interconnects for Speed and Signal Integrity 77
Lumped Versus Distributed Networks 79
Clock Distribution 86
Digital Communication: Parallel Versus Serial Ports 91
Clocking Methods for Serial Ports 91
Starting Edge Synchronization 91
Parallel Clock 92
Manchester Code Self-Clocking 92
Embedded Clock and Run Length Limited Codes 93
Digital Communication: Features and Definitions 93
Serial Data: Shared Ground, Low Speed 97
viii | Table of Contents
Universal Asynchronous Receiver Transmitter 97
Inter-Integrated Circuit and System Management Bus 98
Serial Peripheral Interface 99
Single-Wire Interfaces 101
Serial Data: Shared Ground, High Speed 101
Data Between Boards or Between Systems: Wired Methods 103
RS-232: Serial Data over Cable 103
RS-485: Differential Serial Data over Cable 105
Controller Area Network 107
Serial Data for Computer Systems 108
Universal Serial Bus 108
Serial Advanced Technology Attachment 110
Peripheral Component Interconnect Express 111
Ethernet 113
Wireless Serial Interfaces 115
WiFi 115
Bluetooth 116
Bluetooth Low Energy 117
ZigBee 118
Z-Wave 119
Adaptive Network Topology 120
Other Data Communication Methods 120
Infrared 120
Fiber-Optic Data: Go Fast, Go Far 120
JTAG: PCB Access for Test and Configuration 121
Summary and Conclusions 123
Further Reading 124
4. Power Systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
Split Phase AC Mains Power 128
AC Power Safety: Defining the Problem 129
High-Voltage and Low-Voltage Partitioning 129
Safe Failure Methods and Single Fault Safe Scenarios 130
Overcurrent Protection Methods and the Weakest Link 131
AC/DC Conversion 133
The Classic Approach: 60 Hz Transformers 133
Off-line Switchers 134
Multi-PCB Systems: The Need for Local Power Regulation 135
DC/DC Conversion: Linear Versus Switching 135
Linear Regulators: Conceptual 136
Emitter Follower Regulators Versus LDO 136
Switching Step-Down (Buck) Converter 138
Table of Contents | ix
Switching Step-Up (Boost) Converter 140
Switching Buck-Boost Converter 141
Picking Regulators and Configuring a Power System 142
Including Power Supply Monitors 146
Power Bypass, Decoupling, and Filtering 146
Radiated Noise Reduction: RC Snubbers, Ferrites, and Filters 147
Power Output Noise Reduction: Damped LPF Networks
and Cascaded Regulators 148
Power Grid Current Surges Due to Digital Logic 148
Low-Impedance Power and Ground Planes 149
Power Supply Bypass Filtering: Distributed Stabilization 150
Bypass Capacitors at High Frequencies 151
Power Bypass Capacitor Value and Distribution 153
Summary and Conclusions 156
Further Reading 157
5. Battery Power. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
Battery Basics: Definitions 160
Decision Guidelines for Rechargeable or Single-Use Batteries 164
Defining Power Requirements 165
Battery Discharge Versus Functional Voltage Range 166
Battery Types by Chemistry 167
Discharging Behavior of Batteries 171
Designing a Battery Set: Single Use and Multiple Cells 174
Designing a Rechargeable Custom Battery Pack 177
Charging Batteries 183
Smart Batteries 185
Regulations and Safety for Batteries 187
Other Energy Storage and Access Methods 188
Supercapacitors 188
Hydrogen Fuel Cells 188
Flow Batteries 190
Wireless Power 190
Solid State Batteries 192
Summary and Conclusions 193
Further Reading 194
6. Electromagnetic Interference and Electrostatic Discharge. . . . . . . . . . . . . . . . . . . . . . . 195
Preliminary Ideas 196
Intrinsic Noise 197
General Strategy Dealing with EMI 198
Regulations and Requirements 199
x | Table of Contents
Visualizations of Noise Coupling 201
Frequency Domain Analysis of EMI 203
Grounding 209
Reducing Conducted Emissions to AC Power Mains 214
Cable Interconnect Strategies 215
Reducing Noise Generation at the Source 217
Slower Clocks and Softer Transitions 217
LVDS for Digital Data to Reduce EMI 218
Spread Spectrum Clocks to Reduce EMI 219
EMI Reduction for Switched-Mode Power Supplies 219
Unintentional EMI Antennas 221
EMI Suppression on Motors 221
Reducing Noise Coupling Between On-Board Devices 222
Identifying the Big Talkers and Sensitive Listeners 223
Floor-Planning the PCB for Noise 224
Faraday Cage Methods to Contain or Protect from EMI 226
Making Circuits Less Noise Sensitive 227
Noise-Sensitive High-Impedance Nodes 227
Noise Immunity of Differential Signals 228
Noise Immunity Through Bandwidth Limiting 229
Suppressing Noise into and Out of the System: Faraday Cage Techniques 231
Electrostatic Discharge Protection 234
Summary and Conclusions 241
Further Reading 243
7. Data Converters: ADCs and DACs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245
DAC Performance Basics 246
ADC Performance Basics 251
Antialiasing Filters for ADC Inputs 254
Pulse Width Modulation DACs 255
Arbitrary Waveform Generation by Direct Digital Synthesis 260
Summary and Conclusions 261
Further Reading 262
8. Driving Peripheral Devices. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263
Switched Driver Circuits 264
High- and Low-Side Switching 264
High-Power Load Isolation 265
Drive Signal Strategies 266
Power Transistor Selection 267
Power Transistor Thermal Performance 272
Driving LEDs and Buzzers 275
Table of Contents | xi
Selection of Static Displays 278
Streaming Video Output 279
Driving Inductive Loads 280
Transient Current in a Switched Inductor 280
Driving Solenoids and Relays 282
H-Bridge Drive Circuits 283
Driving DC Motors 286
Motor Selection 286
Brushed DC Motor Driver Circuit 288
Brushless DC Motors: Single and Three Phase 288
Motors with Integrated Control Electronics 289
Stepper Motors 290
Voice Coil Motors 292
Stall Currents and Protecting from Self-Destruction 293
Audio Outputs 294
Summary and Conclusions 296
Further Reading 297
9. Sensing Peripheral Devices. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299
Sensors for Everything 300
Sensor Output Types 300
Sensor Data Capture and Calibration 302
Data Capture Method 302
Sensor Calibration 303
Sensor Response Time 303
Two-State Devices: Switches, Optical Interrupters, and Hall Sensors 304
Position and Rotation Encoders 307
Analog-Linear Sensors: A Closer Look 308
Characteristics of Analog Sensors 309
Signal Processing for Analog Sensors 311
Sensor Calibration 312
Current Sensing Methods 315
Voltage Sensing 317
Specific Sensor Applications 318
Pressure Sensors 318
Temperature Sensors 319
Strain Gauges 322
Sound and Microphones 325
Image Sensors and Video Cameras 329
Touch Panels 332
Summary and Conclusions 337
Further Reading 338
xii | Table of Contents
10. Digital Feedback Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 339
Overview of Sequence and Feedback Control 340
Digital Versus Analog Circuit Methods 342
Preliminary Definitions and Concepts 344
Transfer Functions, Block Diagrams, and Basic Feedback 345
Transient Response Terminology 347
DUC Performance Selection 349
Sequence Control 354
Select Topics in Analog Control Systems 359
Linear Systems and Approximations 361
Bode Plots for Stable Control Loops 363
Bode Plots for Gain and Phase Response 365
Bode Plots for Gain and Phase of a Control Loop 367
Bode Plots for Integral and Derivative Response 370
Bode Plots of Fixed Time Delays 371
Transition to Digital Control 372
Determine DUC Stability 373
DAC Performance Requirements 374
Accuracy of Control Math 376
ADC Performance Requirements 376
ADC Sampling Rate Determination 377
Final Selection of ADC and DAC 378
Dual-Clock Strategy for Improved Phase Margin 378
Digital Trapezoid Integration 379
Digital Integration: Limit Windup and Avoid Saturation 380
Digital Derivative by Adjacent Samples 381
Additive Time Delays in the DSP 382
PID Control Implementation 382
Response Variants: P, I, PI, and PID 385
Typical Effects of Gain Adjustments 389
Ziegler Nichols Tuning 390
Chien–Hrones–Reswick Tuning 394
Component Variance and Control Tuning 396
Adaptive Control Methods 397
Trajectory Control Methods 399
Summary and Conclusions 404
Further Reading 406
11. Schematic to PCB. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 407
PCB Terminology 408
PCB Design (EDA) Tools 411
Getting Started 411
Table of Contents | xiii
Component Selection 411
Selecting RLC Components 412
Picking Connectors for Off-Board Wires 415
Selecting IC Packages 416
Checking Component End of Life and High-Quantity Availability 417
Including Test Access and Interface Ports 417
Schematics 418
Schematic Sheets and General Organization 418
Symbol Organization for Integrated Circuits 422
Placeholders and “Do Not Populate” Components 423
Provide Generous Commentary 423
Avoid Ambiguity 424
Call Out Items Requiring Special Attention 424
Bill of Materials 425
Defining Physical, Control, and Data Layers 425
Defining a Component Footprint 426
Mechanical Definition of a PCB 428
Metric Versus Imperial Measurements 428
PCB Mounting 429
Electrical Grounding Through Mechanical Mounts 430
Drilled Hole Spacing and Keep-Outs 430
Cables to the PCB 430
PCB Alignment References 431
Conformal Coating 432
Test Fixture Using Bed of Nails 432
Defining the PCB Layer Stack-Up 432
Interplane Capacitance 438
Physical Design Rules 439
High-Voltage Spacing Rules 443
Component Placement Strategy 444
General Interconnection Methods 447
Easy Estimations of RLC Parasitics 447
Maximum Trace Currents 448
Determine Minimum Geometry Trace Requirements 449
Vias and Micro-Vias 450
Vias for Thermal Conduction 454
Specialized Interconnection Methods 455
Differential Signal Routing 455
Microstrip Transmission Lines 455
Stripline Transmission Lines 456
Differential Microstrips and Striplines 457
Kelvin Connections 457
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EMI and ESD Strategies 458
Solid Ground Plane for Less EMI 458
Flooded Signal Layer Grounds for Less EMI 459
ESD Interconnect 460
High-Frequency Power Bypass Methods 461
Features for Manufacture and Assembly 461
Consistent Copper Coverage 461
Panelization and Break-Apart Methods 462
Fabrication Notes 463
Manufacturing (Gerber) Files 464
Summary and Conclusions 466
Further Reading 467
12. Software and Coding. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 469
Coding Languages 470
Operating Systems 470
Picking an RTOS 471
Additional RTOS Considerations 474
Configuring Ports and Processors 475
Device Drivers 476
Problematic Portability 477
Peripheral Communication 477
Initiating Peripheral Communication 478
Device Driver Features 479
Modularity/Hierarchy for DD Code 480
Testing the DD 480
Defensive Coding Methods 480
Preprocess Data Inputs (Invalid Data) 481
Preprocess Data Inputs (Bandwidth Restrictions) 481
Preprocess Data (Human Input) 481
Background Reinitialization 482
Watchdog Timers 483
Multicontroller Coding 484
Suggestions for Well-Organized Code 485
Summary and Conclusions 487
Further Reading 488
13. Special Systems and Applications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 489
Different Electronics for Different Priorities 490
Design Priorities 490
Product Cost 490
Quality and Reliability 490
Table of Contents | xv
Power Consumption 491
Safety 491
Backward Compatibility 491
Ruggedness and User Abuse 491
Capability for Repair 492
Navigating the Regulatory Maze 492
Risk Analysis 497
Aviation Electronics (Avionics) 499
Design Priorities 499
Special Needs 499
Regulations, Certifications, and Approvals 500
Satellites and Spacecraft (Astrionics) 500
Radiation 501
Thermal Extremes 502
Vibration, Shock, and Acceleration 502
Vacuum Environments 502
Component Selection and NASA-Approved Parts 503
PCB Materials and Layout 503
Limited Life of Spacecraft 504
Regulations, Certifications, and Approvals 505
Military Electronics 506
Design Priorities and Unique Requirements 507
Regulations, Certifications, and Approvals 507
Medical Devices 509
Regulations, Certifications, and Approvals 509
Clean Functionality Throughout EMC Tests 511
Special Needs 512
Regulatory Requirements for Software and Firmware 515
Automotive 516
Typical Electronic Control Units 516
Design Priorities and Special Needs 517
Regulations, Certifications, and Approvals 518
Consumer Electronics 521
Design Priorities 521
Special Interest Groups, Technology Coalitions, and Technical Standards 522
Regulations, Certifications, and Approvals 523
Restriction of Hazardous Substances 524
Registration, Evaluation, Authorization,
and Restriction of Chemicals (REACH) 524
Industrial Automation 525
Summary and Conclusions 528
Further Reading 529
xvi | Table of Contents
14. Creating Great Products. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 531
Create Products That Solve Problems or Fulfill a Need 532
Identify the Target Market 533
Identify What the Customer Wants 533
Examine Competing Products 534
Define the Value Proposition 535
Determine Viable Pricing 535
Determine a Properly Timed Market Window 535
Establish Coalitions and Strategic Partners 536
Focus on Ease of Use 536
Determine the Needed Resources 537
Get Design Specification Consensus 537
Minimal Design and Feature Creep 537
Identify Obstacles Early 538
Get User Feedback on Prototype Builds 538
Make It Easy to Manufacture 539
Summary and Conclusions 539
Further Reading 540
Glossary of Acronyms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 541
Index. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 551
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