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Hall-Effect Sensors

Book Description

Without sensors most electronic applications would not exist—sensors perform a vital function, namely providing an interface to the real world. Hall effect sensors, based on a magnetic phenomena, are one of the most commonly used sensing technologies today. In the 1970s it became possible to build Hall effect sensors on integrated circuits with onboard signal processing circuitry, vastly reducing the cost and enabling widespread practical use. One of the first major applications was in computer keyboards, replacing mechanical contacts. Hundreds of millions of these devices are now manufactured each year for use in a great variety of applications, including automobiles, computers, industrial control systems, cell phones, and many others.

The importance of these sensors, however, contrasts with the limited information available. Many recent advances in miniaturization, smart sensor configurations, and networkable sensor technology have led to design changes and a need for reliable information. Most of the technical information on Hall effect sensors is supplied by sensor manufacturers and is slanted toward a particular product line. System design and control engineers need an independent, readable source of practical design information and technical details that is not product- or manufacturer-specific and that shows how Hall effect sensors work, how to interface to them, and how to apply them in a variety of uses. This book covers:
• the physics behind Hall effect sensors
• Hall effect transducers
• transducer interfacing
• integrated Hall effect sensors and how to interface to them
• sensing techniques using Hall effect sensors
• application-specific sensor ICs
• relevant development and design tools

This second edition is expanded and updated to reflect the latest advances in Hall effect devices and applications!

Information about various sensor technologies is scarce, scattered and hard to locate. Most of it is either too theoretical for working engineers, or is manufacturer literature that can’t be entirely trusted. Engineers and engineering managers need a comprehensive, up-to-date, and accurate reference to use when scoping out their designs incorporating Hall effect sensors.

* A comprehensive, up-to-date reference to use when crafting all kinds of designs with Hall effect sensors

*Replaces other information about sensors that is too theoretical, too biased toward one particular manufacturer, or too difficult to locate

*Highly respected and influential author in the burgeoning sensors community

Table of Contents

  1. Cover image
  2. Title page
  3. Table of Contents
  4. Copyright
  5. Introduction
  6. Chapter 1: Hall-Effect Physics
    1. 1.1 A Quantitative Examination
    2. 1.2 Hall Effect in Metals
    3. 1.3 The Hall Effect in Semiconductors
    4. 1.4 A Silicon Hall-Effect Transducer
  7. Chapter 2: Practical Transducers
    1. 2.1 Key Transducer Characteristics
    2. 2.2 Bulk Transducers
    3. 2.3 Thin-Film Transducers
    4. 2.4 Integrated Hall Transducers
    5. 2.5 Transducer Geometry
    6. 2.6 The Quad Cell
    7. 2.7 Variations on the Basic Hall-Effect Transducer
    8. 2.8 Examples of Hall Effect Transducers
  8. Chapter 3: Transducer Interfacing
    1. 3.1 An Electrical Transducer Model
    2. 3.2 A Model for Computer Simulation
    3. 3.3 Voltage-Mode Biasing
    4. 3.4 Current-Mode Biasing
    5. 3.5 Amplifiers
    6. 3.6 Amplifier Circuits
    7. 3.7 Analog Temperature Compensation
    8. 3.8 Offset Adjustment
    9. 3.9 Dynamic Offset Cancellation Technique
  9. Chapter 4: Integrated Sensors: Linear and Digital Devices
    1. 4.1 Linear Sensors
    2. 4.2 Linear Transfer Curve
    3. 4.3 Drift
    4. 4.4 Ratiometry
    5. 4.5 Output Characteristics
    6. 4.6 Bandwidth
    7. 4.7 Noise
    8. 4.8 Power Supply Requirements for Linear Sensors
    9. 4.9 Temperature Range
    10. 4.10 Field-Programmable Linear Sensors
    11. 4.11 Typical Linear Devices
    12. 4.12 Switches and Latches
    13. 4.13 Definition of Switch vs. Latch
    14. 4.14 Switchpoint Stability
    15. 4.15 Bipolar Switches
    16. 4.16 Power Supply Requirements for Digital Sensors
    17. 4.17 Output Drivers
    18. 4.18 Typical Digital Devices
  10. Chapter 5: Interfacing to Integrated Hall-Effect Devices
    1. 5.1 Interface Issues—Linear Output Sensors
    2. 5.2 Offset and Gain Adjustment
    3. 5.3 Output Thresholding
    4. 5.4 Interfacing to Switches and Latches
    5. 5.5 The Pull-Up Resistor
    6. 5.6 Interfacing to Standard Logic Devices
    7. 5.7 Discrete Logic
    8. 5.8 Driving Loads
    9. 5.9 LED Interfaces
    10. 5.10 Incandescent Lamps
    11. 5.11 Relays, Solenoids, and Inductive Loads
    12. 5.12 Wiring-Reduction Schemes
    13. 5.13 Encoding and Serialization
    14. 5.14 Digital-to-Analog Encoding
    15. 5.15 Mini-Networks
    16. 5.16 Voltage Regulation and Power Management
  11. Chapter 6: Proximity-Sensing Techniques
    1. 6.1 Head-On Sensing
    2. 6.2 Slide-By Sensing
    3. 6.3 Magnet Null-Point Sensing
    4. 6.4 Float-Level Sensing
    5. 6.5 Linear Position Sensing
    6. 6.6 Rotary Position Sensing
    7. 6.7 Vane Switches
    8. 6.8 Some Thoughts on Designing Proximity Sensors
  12. Chapter 7: Current-Sensing Techniques
    1. 7.1 Resistive Current Sensing
    2. 7.2 Free-Space Current Sensing
    3. 7.3 Free-Space Current Sensors II
    4. 7.4 Toroidal Current Sensors
    5. 7.5 Analysis of Slotted Toroid
    6. 7.6 Toroid Material Selection and Issues
    7. 7.7 Increasing Sensitivity with Multiple Turns
    8. 7.8 An Example Current Sensor
    9. 7.9 A Digital Current Sensor
    10. 7.10 Integrated Current Sensors
    11. 7.11 Closed-Loop Current Sensors
  13. Chapter 8: Speed and Timing Sensors
    1. 8.1 Competitive Technologies
    2. 8.2 Magnetic Targets
    3. 8.3 Vane Switches
    4. 8.4 Geartooth Sensing
    5. 8.5 Geartooth Sensor Architecture
    6. 8.6 Single-Point Sensing
    7. 8.7 Single-Point/Fixed-Threshold Schemes
    8. 8.8 Single-Point/Dynamic-Threshold Schemes
    9. 8.9 Differential Geartooth Sensors
    10. 8.10 Differential Fixed-Threshold
    11. 8.11 Differential Variable-Threshold
    12. 8.12 Comparison of Hall-Effect Speed Sensing Methods
    13. 8.13 Speed and Direction Sensing
    14. 8.14 How Fast Do Speed Sensors Go?
  14. Chapter 9: Application-Specific Sensors
    1. 9.1 Micropower Switches
    2. 9.2 Two-Wire Switches
    3. 9.3 Power Devices
    4. 9.4 Power + Brains = Smart Motor Control
  15. Chapter 10: Development Tools
    1. 10.1 Electronic Bench Equipment
    2. 10.2 Magnetic Instrumentation
    3. 10.3 Mechanical Tools
    4. 10.4 Magnetic Simulation Software
  16. Appendix A: A Brief Introduction to Magnetics
  17. Appendix B: Supplier List
  18. Appendix C: Glossary of Common Terms
  19. Appendix D: References and Bibliography
  20. About the Author
  21. Index