Troubleshooting Switching Power Converters

Book description

Power Supply design is all about detail. And a large part of that detail lies in the practical domain, largely because of the typically small number of microseconds of switching periods involved, and the even smaller tens of nanoseconds of switch transition times --- all these, in effect accentuating various "second-order" effects, that eventually end up playing prime havoc with "normal" expectations of how the circuit should behave. So not unsurprisingly, even after reading several books, most readers still find themselves no closer to the ultimate goal of designing an actual power supply.

Sooner or later, all engineers start realizing the hard fact that designing a switching power supply isn't the trivial task it once seemed to be. But even after years of successfully mastering the underlying theory, the ultimate goal of creating a cost-effective, reliable and commercially viable power supply may still remain a distant dream, since success ultimately hinges on experience. That is, in fact, what clearly differentiates a senior and seasoned power supply engineer from the others --- the ability to navigate and surmount a veritable minefield of tricky issues that can only be learned the hard way, by actual hands-on experience on the job.

This book presents practical knowledge the author acquired rather painfully, while working "in the trenches" for several years in major engineering companies scattered across several continents. This is intended to be the mythical senior engineer's "bag of tricks," finally made available in the form of an easy-to-read book on your shelf. This book will make life for the ambitious power supply engineer much simpler --- besides reducing significantly, the rigorous requirement of having to be a senior engineer's protégé for years on end, just to gain a small measure of real success in this field.

* A practical presentation that answers the important question: why is my switching converter behaving so differently than what I was expecting on the basis of my paper design? And how do I bridge that huge gap?
* For the first time, a systematic and thorough discussion of troubleshooting switching power supplies.
* Coverage of AC/DC and DC/DC power supplies.
* Bench Evaluation of semiconductor ICs used in power conversion --- describing standard and unusual techniques mastered by the author, while testing similar chips at National Semiconductor.
* Detailed coverage of vital topics that haven't been covered by available sources --- grounding systems, the subtleties of component datasheets, and using instruments and probes effectively.
* Systematic investigation (type of failure mechanism, topology, etc.) and solutions for 5 years of reported power supply issues on a prominent, public web forum. This approach will ensure that engineers will not repeat the same mistakes.
* A unique, readable style: personal and direct; no mystification--- just the plain truth, easily and logically explained, with plenty of pictures, graphs and plots.

Table of contents

  1. Front cover
  2. Troubleshooting Switching Power Converters: A Hands-on Guide
  3. Copyright page
  4. Table of contents
  5. Preface
  6. Acknowledgments
  7. CHAPTER 1: Thinking Power
    1. Practice and Theory: Two Sides of the Same Coin
    2. Leave Your Past Perceptions Behind
    3. Choose Your Friends Carefully
    4. Finding Solutions that Converge
    5. The Ripple Effect in Power Supplies
    6. Experience Does Count; No Ifs, Ands, or Buts about That
    7. Never Ignore a Problem Until It Is Too Late
    8. Know Your Instruments Well
    9. Heatseekers: On the Road with Symptomatic Troubleshooting
    10. Causality Can Be the First Casualty (1/2)
    11. Causality Can Be the First Casualty (2/2)
    12. Learn from (Their) Mistakes
    13. The Problem with Problem Solving (1/2)
    14. The Problem with Problem Solving (2/2)
  8. CHAPTER 2: High-Frequency Effects and the Importance of Input Decoupling
    1. Lies, Damn Lies, and Schematics
    2. Occupational Hazards
    3. Watch the Feedback Trace Closely
    4. Physical Distances Become Critical
    5. Estimating Harmonic Amplitudes
    6. High-Frequency Input Decoupling
    7. Don’t Forget to Place that 0.1mF Ceramic Capacitor Really Close to the IC
    8. You Need Bulk Capacitance, Too
    9. Where Is the “Missing” Current Coming From?
    10. Check Your Bench Power Supply
    11. Lack of Bulk Capacitance and/or Too Much ESR Can Play Havoc
    12. Single Ceramic Capacitor for Both Noise and Ripple?
    13. The Control Also Needs a Clean Supply Rail
    14. Boost Topology Decoupling Is Slightly Different
  9. CHAPTER 3: Output Noise and Filtering
    1. Measuring Output Noise and Ripple
  10. CHAPTER 4: Using Capacitors Wisely
    1. Introduction
    2. Part 1: Aluminum Electrolytics
    3. Part 2: Ceramic Capacitors (1/4)
    4. Part 2: Ceramic Capacitors (2/4)
    5. Part 2: Ceramic Capacitors (3/4)
    6. Part 2: Ceramic Capacitors (4/4)
  11. CHAPTER 5: Maximizing the Effectiveness of the Ground Plane
    1. How to Parallel Output Capacitors for Proper Sharing
    2. Integrated Switcher IC Solutions Versus Controller IC Solutions
    3. Quick Check on Current through Aluminum Capacitors
    4. Secondary Side Trace Inductances and Their Impact on Efficiency
    5. Current Return Paths in the Ground Plane
    6. Paralleling Traces to Reduce Inductance
  12. CHAPTER 6: Printed Circuit Board Layout for AC-DC and DC-DC Converters
    1. Introduction
    2. Evaluation Boards (EVBs)
  13. CHAPTER 7: Working without a Ground Plane
    1. 384x-based Controllers on Single-sided Boards
    2. Watch the Primary Side Current Loop
    3. And the Secondary Side Current Loop, Too
    4. The Real “Switch”
  14. CHAPTER 8: Home-Grown Strategies in Troubleshooting
    1. Peeling the Onion
  15. CHAPTER 9: Effective Bench Work
    1. Introduction
    2. Basic Equipment
  16. CHAPTER 10: Efficiency Rules
    1. Ensure the Drive Is Adequate
    2. Minimize Capacitive Parasitics
    3. Proper Design of Snubbers and Clamps
    4. Varying the Frequency
    5. The Time-sharing Principle
    6. Understanding the Shape of Buck Efficiency Curves
    7. Estimating the Ratio of Conduction Loss to Switching Loss (1/2)
    8. Estimating the Ratio of Conduction Loss to Switching Loss (2/2)
  17. CHAPTER 11: Magnetics, EMI, and Noise
    1. The Wish List
    2. Twisting and Turning Your Way Out of EMI Problems
    3. Location of Clamp Affects Noise, Too
    4. A Cheat-sheet for EMI Troubleshooting (1/2)
    5. A Cheat-sheet for EMI Troubleshooting (2/2)
  18. CHAPTER 12: Discussion Forums, Datasheets, and Other Real-World Issues
    1. Thinking Is the Key
    2. Cross-check Everything
    3. Product Liability Concerns
    4. It’s All about the Customer
    5. The Q&A Session (1/8)
    6. The Q&A Session (2/8)
    7. The Q&A Session (3/8)
    8. The Q&A Session (4/8)
    9. The Q&A Session (5/8)
    10. The Q&A Session (6/8)
    11. The Q&A Session (7/8)
    12. The Q&A Session (8/8)
  19. Appendix
  20. Index (1/3)
  21. Index (2/3)
  22. Index (3/3)

Product information

  • Title: Troubleshooting Switching Power Converters
  • Author(s): Sanjaya Maniktala
  • Release date: April 2011
  • Publisher(s): Newnes
  • ISBN: 9780080551258