You are previewing Switching Power Supplies A - Z, 2nd Edition.
O'Reilly logo
Switching Power Supplies A - Z, 2nd Edition

Book Description

This book is the most comprehensive study available of the theoretical and practical aspects of controlling and measuring Electromagnetic Interference in switching power supplies, including input filter instability considerations.

The new edition is thoroughly revised with six completely new chapters, while the existing EMI chapters are expanded to include many more step-by-step numerical examples and key derivations and EMI mitigation techniques. New topics cover the length and breadth of modern switching power conversion techniques, lucidly explained in simple but thorough terms, now with uniquely detailed "wall-reference charts" providing easy access to even complex topics.



  • Step-by-step and iterative approach for calculating high-frequency losses in forward converter transformers, including Proximity losses based on Dowell's equations
  • Thorough, yet uniquely simple design flow-chart for building DC-DC converters and their magnetic components under typical wide-input supply conditions
  • Step-by-step, solved examples for stabilizing control loops of all three major topologies, using either transconductance or conventional operational amplifiers, and either current-mode or voltage-mode control

Table of Contents

  1. Cover Image
  2. Contents
  3. Title
  4. Copyright
  5. Preface
  6. Acknowledgments
  7. Chapter 1. The Principles of Switching Power Conversion
    1. Introduction
    2. Overview and Basic Terminology
    3. Understanding the Inductor
    4. Evolution of Switching Topologies
  8. Chapter 2. DC–DC Converter Design and Magnetics
    1. DC Transfer Functions
    2. The DC Level and the “Swing” of the Inductor Current Waveform
    3. Defining the AC, DC, and Peak Currents
    4. Understanding the AC, DC, and Peak Currents
    5. Defining the “Worst-Case” Input Voltage
    6. The Current Ripple Ratio “r”
    7. Relating r to the Inductance
    8. The Optimum Value of r
    9. Do We Mean Inductor? or Inductance?
    10. How Inductance and Inductor Size Depend on Load Current
    11. How Vendors Specify the Current Rating of an Off-the-shelf Inductor and How to Select It
    12. What Is the Inductor Current Rating We Need to Consider for a Given Application?
    13. The Spread and Tolerance of the Current Limit
    14. Worked Example (1)
    15. Worked Examples (2, 3, and 4)
    16. Worked Example (5) — When Not to Increase the Number of Turns
    17. Worked Example (6) — Characterizing an Off-the-Shelf Inductor in a Specific Application
    18. Calculating “Other” Worst-case Stresses and their Selection Criteria
  9. Chapter 3. Off-Line Converter Design and Magnetics
    1. Flyback Converter Magnetics
  10. Chapter 4. The Topology FAQ
    1. Questions and Answers
  11. Chapter 5. Advanced Magnetics
    1. Part 1: Energy Transfer Principles
    2. Part 2: Energy to Core Sizes
    3. Part 3: Toroids to E-Cores
    4. Part 4: More on AC–DC Flyback Transformer Design
    5. Part 5: More on AC–DC Forward Converter Transformer Design
  12. Chapter 6. Component Ratings, Stresses, Reliability, and Life
    1. Introduction
    2. Stresses and Derating
    3. Part 1: Ratings and Derating in Power Converter Applications
    4. Part 2: MTBF, Failure Rate, Warranty Costs, and Life
    5. Part 3: Life Prediction of Aluminum Electrolytic Capacitors
  13. Chapter 7. Optimal Power Components Selection
    1. Overview
    2. The Key Stresses in Power Converters
    3. Waveforms and Peak Voltage Stresses for Different Topologies
    4. The Importance of RMS and Average Currents
    5. Calculation of RMS and Average Currents for Diode, FET, and Inductor
    6. Calculation of RMS and Average Currents for Capacitors
    7. The Stress Spiders
    8. Stress Reduction in AC–DC Converters
    9. RCD Clamps versus RCD Snubbers
  14. Chapter 8. Conduction and Switching Losses
    1. Switching a Resistive Load
    2. Switching an Inductive Load
    3. Switching Losses and Conduction Loss
    4. A Simplified Model of the MOSFET for Studying Inductive Switching Losses
    5. The Parasitic Capacitances Expressed in an Alternate System
    6. Gate Threshold Voltage
    7. The Turn-On Transition
    8. The Turn-Off Transition
    9. Gate Charge Factors
    10. Worked Example
    11. Applying the Switching Loss Analysis to Switching Topologies
    12. Worst-Case Input Voltage for Switching Losses
    13. How Switching Losses Vary with the Parasitic Capacitances
    14. Optimizing Driver Capability vis-à-vis MOSFET Characteristics
  15. Chapter 9. Discovering New Topologies
    1. Part 1: Fixed-Frequency Synchronous Buck Topology
    2. Part 2: Fixed-Frequency Synchronous Boost Topology
    3. Part 3: Current-Sensing Categories and General Techniques
    4. Part 4: The Four-Switch Buck-Boost
    5. Part 5: Auxiliary Rails and Composite Topologies
    6. Part 6: Configurations and “Topology Morphology”
    7. Part 7: Other Topologies and Techniques
  16. Chapter 10. Printed Circuit Board Layout
    1. Introduction
    2. Trace Section Analysis
    3. Some Points to Keep in Mind During Layout
    4. Thermal Management Concerns
  17. Chapter 11. Thermal Management
    1. Thermal Resistance and Board Construction
    2. Historical Definitions
    3. Empirical Equations for Natural Convection
    4. Comparing the Two Standard Empirical Equations
    5. Sizing Copper Traces
    6. Natural Convection at an Altitude
    7. Forced Air Cooling
    8. Radiative Heat Transfer
    9. Miscellaneous Issues
  18. Chapter 12. Feedback Loop Analysis and Stability
    1. Transfer Functions, Time Constant, and the Forcing Function
    2. Understanding “e” and Plotting Curves on Log Scales
    3. Flashback: Complex Representation
    4. Repetitive and Nonrepetitive Stimuli: Time Domain and Frequency Domain Analyses
    5. The s-Plane
    6. Laplace Transform Method
    7. Disturbances and the Role of Feedback
    8. Transfer Function of the RC Filter, Gain, and the Bode Plot
    9. The Integrator Op-amp (“Pole-at-Zero” Filter)
    10. Mathematics in the Log-Plane
    11. Transfer Function of the Post-LC Filter
    12. Summary of Transfer Functions of Passive Filters
    13. Poles and Zeros
    14. “Interactions” of Poles and Zeros
    15. Closed and Open-Loop Gain
    16. The Voltage Divider
    17. Pulse-Width Modulator Transfer Function
    18. Voltage (Line) Feedforward
    19. Power Stage Transfer Function
    20. Plant Transfer Functions of All the Topologies
    21. Feedback-Stage Transfer Functions
    22. Closing the Loop
    23. Criteria and Strategy for Ensuring Loop Stability
    24. Plotting the Open-Loop Gain for the Three Topologies
    25. The ESR-Zero
    26. High-Frequency Pole
    27. Designing a Type 3 Op-Amp Compensation Network
    28. Optimizing the Feedback Loop
    29. Input Ripple Rejection
    30. Load Transients
    31. Type 1 and Type 2 Compensations
    32. Transconductance Op-Amp Compensation
    33. Simpler Transconductance Op-Amp Compensation
    34. Compensating with Current-Mode Control
  19. Chapter 13. Advanced Topics
    1. Part 1: Voltage Ripple of Converters
    2. Part 2: Distributing and Reducing Stresses in Power Converters
    3. Part 3: Coupled Inductors in Interleaved Buck Converters
    4. Part 4: Load Sharing in Paralleled Converters
  20. Chapter 14. The Front End of AC–DC Power Supplies
    1. Overview
    2. Part 1: Low-Power Applications
    3. Part 2: High-Power Applications and PFC
  21. Chapter 15. EMI Standards and Measurements
    1. Part 1: Overview and Limits
    2. Part 2: Measurements of Conducted EMI
  22. Chapter 16. Practical EMI Line Filters and Noise Sources in Power Supplies
    1. Part 1: Practical Line Filters
    2. Part 2: DM and CM Noise in Switching Power Supplies
  23. Chapter 17. Fixing EMI Across the Board and Input Filter Instability
    1. Part 1: Practical Techniques for EMI Mitigation
    2. Part 2: Modules and Input Instability
  24. Chapter 18. The Math Behind the Electromagnetic Puzzle
    1. Fourier Series in Power Supplies
    2. The Rectangular Wave
    3. The Sinc Function
    4. The Envelope of the Fourier Amplitudes
    5. Practical DM Filter Design
    6. DM Calculations at High Line
    7. Practical CM Filter Design
  25. Chapter 19. Solved Examples
    1. Part 1: FET Selection
    2. Part 2: Conduction Losses in the FETs
    3. Part 3: FET Switching Losses
    4. Part 4: Inductor Loss
    5. Part 5: Input Capacitor Selection and Loss
    6. Part 6: Output Capacitor Selection and Loss
    7. Part 7: Total Losses and Efficiency Estimate
    8. Part 8: Junction Temperature Estimates
    9. Part 9: Control Loop Design
  26. Appendix
  27. Index