Switching power supply design & optimization

Title:

Personal Author:

Maniktala, Sanjaya

Publication Information:

New York : McGraw-Hill Professional, 2004

ISBN:

9780071434836

Subject Term:

Switching power supplies

Electronic apparatus and appliances -- Power supply

Electric current converters

Available:*

Library	Item Barcode	Call Number	Material Type	Item Category 1	Status
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This is a rigorous tutorial on power supply design fundamentals. The author details cutting-edge thermal management techniques, grouping key design equations in a special reference section, and includes a concise design FAQ.

Author Notes

Sanjaya Maniktala is a Principal Engineer with National Semiconductor. He holds two patents in power supply technology and has written numerous articles on power supply design, appearing in such magazines as Power Electronics Technology, EDN, Electronic Engineering, and Planet Analog. He lives in Fremont, California.

Preface	p. xi
Acknowledgments	p. xv
About the Authors	p. xvii
Chapter 1. Overview of Switching Power	p. 1
1.1 Introduction	p. 1
1.2 The Voltseconds Law	p. 3
1.3 Basic Waveform Analysis	p. 4
1.4 The r and K of the Current Waveform	p. 7
1.5 Basic Design Procedure for Inductors	p. 9
1.6 Calculating RMS Current for Capacitors	p. 10
1.7 Topologies and Worst-Case Capacitor Currents	p. 11
1.8 Worst-Case Input Voltage for a Power Supply	p. 13
1.9 Using Too High an Inductance (small r)	p. 15
1.10 The Flat-Top Approximation	p. 16
1.11 Tolerance of Set Output Voltage	p. 20
1.12 Preferred Resistor Values	p. 23
1.13 Optimum Divider Selection	p. 25
Chapter 2. DC-DC Converters and Their Configurations	p. 31
2.1 Introduction	p. 31
2.2 What is Ground?	p. 32
2.3 The N-switch and P-switch	p. 33
2.4 The LSD Cell	p. 34
2.5 Configurations of Switching Regulator Topologies	p. 36
2.6 Basic Types of Switcher ICs	p. 38
2.7 Flyback/Buck-Boost/Boost ICs Compared	p. 40
2.8 Other Possible Applications of Buck and Buck-Boost ICs	p. 42
2.9 Some Practical Cases	p. 51
2.10 Differential Voltage Sensing	p. 55
2.11 Some Topology Nuances	p. 56
2.12 Composite Topologies	p. 58
Chapter 3. Reference Equations and Graphs for Converter Design	p. 61
3.1 The Defining Difference between the Topologies	p. 61
3.2 Definition of Current Ripple Ratio	p. 61
3.3 Graphical Tools for Inductor Selection	p. 62
3.4 The Design Equations Table	p. 66
Chapter 4. Discontinuous Conduction Mode Equations	p. 69
4.1 Introduction	p. 69
4.2 How DCM Equations Are Calculated	p. 71
4.3 The Duty Cycle Equations	p. 75
Chapter 5. Front-End of Off-Line Power Supplies	p. 77
5.1 Conventional Front-End Design	p. 77
5.1.1 Input voltage shape	p. 77
5.1.2 The input current shape	p. 84
5.2 Front-End with PFC	p. 87
5.2.1 Regulatory issues	p. 87
5.2.2 Boost PFC	p. 89
5.2.3 Capacitor selection	p. 92
5.2.4 Synchronizing the PFC and PWM stages	p. 95
5.2.5 Synchronization over a wide input range	p. 98
5.2.6 Calculating the high- and low-frequency rms components	p. 100
5.2.7 Sequencing, protection, and some related observations	p. 101
5.2.8 Core losses in the PFC choke	p. 106
Chapter 6. Isolated Topologies for Off-line Applications	p. 109
6.1 The Forward Converter	p. 109
6.1.1 Introduction and overview	p. 109
6.2 The Flyback Topology	p. 114
6.2.1 Introduction	p. 114
6.2.2 The integrated power switch	p. 114
6.2.3 The equivalent buck-boost models	p. 115
6.2.4 A worked example	p. 121
6.2.5 Dealing with multi-output converters	p. 121
6.2.6 The primary-side leakage term	p. 123
6.2.7 The secondary-side leakage term	p. 125
6.2.8 Optimization and analysis	p. 129
6.2.9 Dissipation estimates and efficiency	p. 140
6.2.10 Practical flyback designs using 600-V switches	p. 144
6.2.11 Diode rating for higher V[subscript OR]	p. 145
6.2.12 Pulse-skipping and required preload	p. 145
6.2.13 Overload protection	p. 149
Chapter 7. Concepts in Magnetics	p. 153
7.1 Basic Magnetic Concepts and Definitions (MKS Units)	p. 153
7.2 The Inductor Equation	p. 154
7.3 The Voltage-Independent Equation	p. 155
7.4 The Voltage-Dependent Equation	p. 157
7.5 Units in Magnetics	p. 161
7.6 The Magnetomotive Force (mmf) Equation	p. 163
7.7 Effective Area and Effective Length	p. 165
7.8 The Effect of the Air Gap	p. 166
7.9 The Gap Factor z	p. 168
7.10 The Origin and Significance of z	p. 169
7.11 Relating B to H	p. 171
7.12 E-cores	p. 171
7.13 Energy Storage Considerations	p. 172
First study: ampere-turns constant, (N = constant)	p. 174
Second study: B constant, (N [proportional to] z)	p. 174
Third study: L constant, (N [proportional to] z[superscript 1/2])	p. 175
7.14 How an Air Gap Helps	p. 176
7.15 Understanding L	p. 178
7.16 Difference between an Inductor and (Flyback) Transformer	p. 180
7.17 Transformers	p. 181
7.18 Fringing Flux Correction	p. 185
7.19 Worked Example	p. 188
Chapter 8. Tapped-Inductor Topologies	p. 191
8.1 The Tapped-Inductor Buck	p. 191
8.2 Other Tapped-Inductor Stages and Duty Cycle	p. 196
Chapter 9. Selecting Inductors for DC-DC Converters	p. 199
9.1 Introduction	p. 199
9.2 Specifying the Current Ripple Ratio r	p. 202
9.3 Mapping the Inductor	p. 203
9.4 Voltseconds	p. 204
9.5 Choosing r and L	p. 205
9.6 B in Terms of Current	p. 208
9.7 A Feel for Core Loss Optimization by Understanding Variations	p. 210
Varying the volume of the core	p. 210
Varying the frequency	p. 212
9.8 A Walk-Through Example	p. 214
9.9 Choosing an Inductor	p. 215
9.10 Evaluating the Inductor in Our Application	p. 216
Chapter 10. Flyback Transformer Design	p. 223
10.1 Design Equations	p. 223
10.2 Worked Example (Part 1)	p. 226
10.3 Some Finer Points of Optimization	p. 230
10.4 Rule of Thumb for Quick Selection of Flyback Transformer Cores	p. 231
10.5 Worked Example (Part 2)	p. 232
10.6 Circular mils (cmils)	p. 234
10.7 Current Carrying Capacity of Wires	p. 235
10.8 Skin Depth	p. 237
10.9 A Feel for Wire Gauges	p. 242
10.10 Diameter of Coated Wire	p. 244
10.11 SWG Comparison	p. 245
Chapter 11. Forward Converter Magnetics Design	p. 249
11.1 Introduction	p. 249
11.2 The Transformer and Choke Compared	p. 249
11.3 Introducing the Proximity Effect	p. 253
11.4 More about Skin Depth	p. 254
11.5 Dowell's Equations	p. 256
11.6 The Equivalent Foil Transformation	p. 263
11.7 Some Useful Equations for Quick Selection of Forward Converter Cores	p. 265
11.8 Stacking Wires and Bundles	p. 268
11.9 Core Loss Calculations	p. 269
Chapter 12. PCBs and Layout	p. 273
12.1 Introduction	p. 273
12.2 Trace Analysis	p. 273
12.3 Miscellaneous Points to Note	p. 276
12.4 Routing the Feedback Trace	p. 279
12.5 The Ground Plane	p. 280
12.6 Some Manufacturing Issues	p. 282
12.7 PCB Vendors and Gerber Files	p. 285
Chapter 13. Thermal Management	p. 287
13.1 Introduction	p. 287
13.2 Thermal Measurements and Efficiency Estimates	p. 288
13.3 The Equations of Natural Convection	p. 290
13.4 Historical Definitions	p. 291
13.5 Available Equations	p. 292
13.6 Manipulating the Equations	p. 294
13.7 Comparing the Two Standard Equations	p. 295
13.8 h from Thermodynamic Theory	p. 296
13.9 Working with the Tables of the Standard Equations	p. 297
13.10 PCBs for Heatsinking	p. 301
13.11 Natural Convection at an Altitude	p. 303
13.12 Forced Air Cooling	p. 303
13.13 Radiative Heat Transfer	p. 305
13.14 Miscellaneous Issues	p. 306
Chapter 14. Stabilizing Current Mode Converters	p. 309
14.1 Background	p. 309
14.2 Why Slope Compensation?	p. 312
14.3 Generalized Rule for Avoiding Subharmonic Instability	p. 316
Chapter 15. Practical EMI Filter Design	p. 319
15.1 The CISPR 22 Standard	p. 319
15.2 The LISN	p. 320
15.3 Fourier Series	p. 321
15.4 The Trapezoid	p. 322
15.5 Practical DM Filter Design	p. 323
15.6 Practical CM Filter Design	p. 326
Chapter 16. Things to Try	p. 331
16.1 Introduction	p. 331
16.2 Synchronizing two 3844 ICs	p. 331
16.3 A Self-Oscillating Low-Cost Standby/Auxiliary Power Supply	p. 332
16.4 An Adapter with Battery Charging Function	p. 334
16.5 Paralleling Bridge Rectifiers	p. 335
16.6 Self-Contained Inrush Protection Circuit	p. 335
16.7 Cheap Power Good Signal	p. 336
16.8 An Overcurrent Protection Circuit	p. 336
16.9 Another Overcurrent Protection Circuit	p. 337
16.10 Adding Overtemperature Protection to the 384x Series	p. 337
16.11 Turn-On Snubber for PFC	p. 338
16.12 A Unique Active Inrush Protection Circuit	p. 339
16.13 Floating Drive from a 384x Controller	p. 340
16.14 Floating Buck Topology	p. 340
16.15 Symmetrical Boost Topology	p. 341
16.16 A Slave Converter	p. 342
16.17 A Boost Preregulator with a Regulated Auxiliary Output	p. 343
Chapter 17. Reliability, Testing, and Safety Issues	p. 345
17.1 Introduction	p. 345
17.2 Reliability Definitions	p. 345
17.3 Chi-Square Distribution	p. 347
17.4 Chargeable Failures	p. 349
17.5 Warranty Costs	p. 350
17.6 Calculating Reliability	p. 351
17.7 Testing and Qualifying Power Supplies	p. 352
HAST/HALT, HASS, and ESS	p. 352
17.8 Safety Issues	p. 354
17.9 Calculating Working Voltage	p. 357
17.10 Estimating Capacitor Life	p. 361
17.11 Safety Restrictions on the Total Y-Capacitance	p. 369
17.12 Safety and the 5-cent Zener	p. 370
Appendix. Components and FAQ	p. 373
References	p. 387
Index	p. 389

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Summary

Summary

Author Notes

Table of Contents