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Power Supplies for LED Driving

Book Description

Light-emitting diodes are being widely used due to their efficient use of power. The applications for power LEDs include traffic lights, street lamps, automotive lighting, architectural lights, household light replacements, signage lighting (replacing neon strip lights and fluorescent tubes), and many more.

Powering (driving) these LED's is not always simple. Linear driving is inefficient and generates far too much heat. With a switching supply, the main issues are EMI and efficiency, and of course cost. The problem is to get a design that meets legal requirements and is efficient, while costing the least. This book covers the design trade-offs involved in LED driving applications, from low-power to UB-LEDs and beyond.

* Practical, "hands-on" approach to power supply design for LED drivers
* Detailed examples of what works and why, throughout the design process
* Commentary on how the calculated component value compares with the actual value used, including a description of why the choice was made

Table of Contents

  1. Cover
  2. Title Page
  3. Copyright
  4. Preface
  5. Table of Contents
  6. Chapter 1: Introduction
    1. 1.1 Objectives and General Approach
    2. 1.2 Description of Contents
  7. Chapter 2: Characteristics of LEDs
    1. 2.1 Applications for LEDs
    2. 2.2 Light Measure
    3. 2.3 Equivalent Circuit to an LED
    4. 2.4 Voltage Drop Versus Color and Current
    5. 2.5 Common Mistakes
  8. Chapter 3: Driving LEDs
    1. 3.1 Voltage Source
    2. 3.2 Current Source
    3. 3.3 Testing LED Drivers
    4. 3.4 Common Mistakes
    5. 3.5 Conclusions
  9. Chapter 4: Linear Power Supplies
    1. 4.1 Introduction
    2. 4.2 Advantages and Disadvantages
    3. 4.3 Limitations
    4. 4.4 Common Errors in Designing Linear LED Drivers
  10. Chapter 5: Buck-Based LED Drivers
    1. 5.1 An Example Buck Converter Control IC
    2. 5.2 Buck Circuits for DC Applications
    3. 5.3 Buck Circuits for AC Input
    4. 5.4 Buck Circuits Powered by an AC Phase Dimmer
    5. 5.5 Common Errors in AC Input Buck Circuits
    6. 5.6 Double Buck
    7. 5.7 Hysteretic Buck
  11. Chapter 6: Boost Converters
    1. 6.1 Boost Converter Operating Modes
    2. 6.2 HV9912 Boost Controller
    3. 6.3 Design of a Continuous Conduction Mode Boost LED Driver
    4. 6.4 Design of a Discontinuous Conduction Mode Boost LED Driver
    5. 6.5 Common Mistakes
    6. 6.6 Conclusions
  12. Chapter 7: Boost-Buck Converter
    1. 7.1 The Cuk Converter
      1. 7.1.1 Operation of a Cuk Boost-Buck Converter
      2. 7.1.2 Hysteretic Control of the Boost-Buck Converter
      3. 7.1.3 The Effects of Delay in Hysteretic Control
      4. 7.1.4 Stability of the Boost-Buck Converter
      5. 7.1.5 Dimming Ratio Using PWM Dimming
      6. 7.1.6 Design of the Boost-Buck Converter with HV9930
    2. 7.2 SEPIC Buck-Boost Converters
    3. 7.2.1 Basic SEPIC Equations
    4. 7.3 Buck-Boost Topology
    5. 7.4 Common Mistakes in Boost-Buck Circuits
    6. 7.5 Conclusions
  13. Chapter 8: LED Drivers with Power Factor Correction
    1. 8.1 Power Factor Correction
    2. 8.2 Bi-Bred
    3. 8.3 Buck-Boost-Buck (BBB)
    4. 8.4 Common Mistakes with PFC Circuits
    5. 8.5 Conclusions
  14. Chapter 9: Fly-Back Converters
    1. 9.1 Two Winding Fly-Back
    2. 9.1.1 Fly-Back Example
    3. 9.2 Three Winding Fly-Back
    4. 9.2.1 Design Rules for a Fly-Back Converter
    5. 9.3 Single Winding Fly-Back (Buck-Boost)
  15. Chapter 10: Essentials of Switching Power Supplies
    1. 10.1 Linear Regulators
    2. 10.2 Switching Regulators
  16. Chapter 11: Selecting Components for LED Drivers
    1. 11.1 Discrete Semiconductors
    2. 11.2 Passive Components
    3. 11.3 The Printed Circuit Board (PCB)
    4. 11.4 Operational Amplifiers and Comparators
  17. Chapter 12: Magnetic Materials for Inductors and Transformers
    1. 12.1 Ferrite Cores
    2. 12.2 Iron Dust Cores
    3. 12.3 Special Cores
    4. 12.4 Core Shapes and Sizes
    5. 12.5 Magnetic Saturation
    6. 12.6 Copper Losses
  18. Chapter 13: EMI and EMC Issues
    1. 13.1 EMI Standards
    2. 13.2 Good EMI Design Techniques
    3. 13.3 EMC Standards
    4. 13.4 EMC Practices
  19. Chapter 14: Thermal Considerations
    1. 14.1 Efficiency and Power Loss
    2. 14.2 Calculating Temperature
    3. 14.3 Handling Heat – Cooling Techniques
  20. Chapter 15: Safety Issues
    1. 15.1 AC Mains Isolation
    2. 15.2 Circuit Breakers
    3. 15.3 Creepage Distance
    4. 15.4 Capacitor Ratings
    5. 15.5 Low Voltage Operation
  21. Bibliography
  22. Index
  23. Author Biography
  24. Instructions for online access