Pulse-Width Modulated DC-DC Power Converters

Content: About the Author xxi    Preface xxiii    Nomenclature xxv    1 Introduction 1    1.1 Classification of Power Supplies 1    1.2 Basic Functions of Voltage Regulators 3    1.3 Power Relationships in DC   DC Converters 4    1.4 DC Transfer Functions of DC   DC Converters 5    1.5 Static Characteristics of DC Voltage Regulators 6    1.6 Dynamic Characteristics of DC Voltage Regulators 9    1.7 Linear Voltage Regulators 12    1.8 Topologies of PWM DC   DC Converters 16    1.9 Relationships Among Current, Voltage, Energy, and Power 18    1.10 Summary 19    References 19    Review Questions 20    Problems 21    2 Buck PWM DC   DC Converter 22    2.1 Introduction 22    2.2 DC Analysis of PWM Buck Converter for CCM 22    2.3 DC Analysis of PWM Buck Converter for DCM 52    2.4 Buck Converter with Input Filter 68    2.5 Buck Converter with Synchronous Rectifier 68    2.6 Buck Converter with Positive Common Rail 76    2.7 Quadratic Buck Converter 76    2.8 Tapped-Inductor Buck Converters 79    2.9 Multiphase Buck Converter 83    2.10 Switched-Inductor Buck Converter 85    2.11 Layout 85    2.12 Summary 85    References 87    Review Questions 88    Problems 88    3 Boost PWM DC   DC Converter 90    3.1 Introduction 90    3.2 DC Analysis of PWM Boost Converter for CCM 90    3.3 DC Analysis of PWM Boost Converter for DCM 107    3.4 Bidirectional Buck and Boost Converters 127    3.5 Synchronous Boost Converter 129    3.6 Tapped-Inductor Boost Converters 129    3.7 Duality 133    3.8 Power Factor Correction 134    3.9 Summary 141    References 142    Review Questions 143    Problems 143    4 Buck   Boost PWM DC   DC Converter 145    4.1 Introduction 145    4.2 DC Analysis of PWM Buck   Boost Converter for CCM 145    4.3 DC Analysis of PWM Buck   Boost Converter for DCM 162    4.4 Bidirectional Buck   Boost Converter 180    4.5 Synthesis of Buck   Boost Converter 181    4.6 Synthesis of Boost   Buck (C' uk) Converter 183    4.7 Noninverting Buck   Boost Converters 184    4.8 Tapped-Inductor Buck   Boost Converters 186    4.9 Summary 192    References 192    Review Questions 193    Problems 193    5 Flyback PWM DC   DC Converter 195    5.1 Introduction 195    5.2 Transformers 196    5.3 DC Analysis of PWM Flyback Converter for CCM 197    5.4 DC Analysis of PWM Flyback Converter for DCM 214    5.5 Multiple-Output Flyback Converter 232    5.6 Bidirectional Flyback Converter 237    5.7 Ringing in Flyback Converter 237    5.8 Flyback Converter with Passive Dissipative Snubber 240    5.9 Flyback Converter with Zener Diode Voltage Clamp 240    5.10 Flyback Converter with Active Clamping 241    5.11 Two-Transistor Flyback Converter 241    5.12 Summary 243    References 244    Review Questions 244    Problems 245    6 Forward PWM DC   DC Converter 246    6.1 Introduction 246    6.2 DC Analysis of PWM Forward Converter for CCM 246    6.3 DC Analysis of PWM Forward Converter for DCM 269    6.4 Multiple-Output Forward Converter 288    6.5 Forward Converter with Synchronous Rectifier 288    6.6 Forward Converters with Active Clamping 288    6.7 Two-Switch Forward Converter 290    6.8 Forward   Flyback Converter 291    6.9 Summary 292    References 293    Review Questions 293    Problems 294    7 Half-Bridge PWM DC   DC Converter 296    7.1 Introduction 296    7.2 DC Analysis of PWM Half-Bridge Converter for CCM 296    7.3 DC Analysis of PWM Half-Bridge Converter for DCM 315    7.4 Summary 326    References 327    Review Questions 327    Problems 328    8 Full-Bridge PWM DC   DC Converter 330    8.1 Introduction 330    8.2 DC Analysis of PWM Full-Bridge Converter for CCM 330    8.3 DC Analysis of PWM Full-Bridge Converter for DCM 351    8.4 Phase-Controlled Full-Bridge Converter 361    8.5 Summary 362    References 362    Review Questions 362    Problems 363    9 Small-Signal Models of PWM Converters for CCM and DCM 365    9.1 Introduction 365    9.2 Assumptions 366    9.3 Averaged Model of Ideal Switching Network for CCM 366    9.4 Averaged Values of Switched Resistances 369    9.5 Model Reduction 375    9.6 Large-Signal Averaged Model for CCM 377    9.7 DC and Small-Signal Circuit Linear Models of Switching Network for CCM 381    9.8 Block Diagram of Small-signal Model of PWM DC   DC Converters 385    9.9 Family of PWM Converter Models for CCM 386    9.10 PWM Small-Signal Switch Model for CCM 389    9.11 Modeling of Ideal Switching Network for DCM 391    9.12 Averaged Parasitic Resistances for DCM 398    9.13 Summary 400    References 402    Review Questions 405    Problems 405    10 Small-Signal Characteristics of Buck Converter for CCM 407    10.1 Introduction 407    10.2 Small-Signal Model of the PWM Buck Converter 407    10.3 Open-Loop Transfer Functions 408    10.4 Open-Loop Step Responses 426    10.5 Open-Loop DC Transfer Functions 434    10.6 Summary 436    References 436    Review Questions 437    Problems 438    11 Small-Signal Characteristics of Boost Converter for CCM 439    11.1 Introduction 439    11.2 DC Characteristics 439    11.3 Open-Loop Control-to-Output Transfer Function 440    11.4 Delay in Open-Loop Control-to-Output Transfer Function 449    11.5 Open-Loop Audio Susceptibility 451    11.6 Open-Loop Input Impedance 455    11.7 Open-Loop Output Impedance 457    11.8 Open-Loop Step Responses 461    11.9 Summary 467    References 467    Review Questions 468    Problems 468    12 Voltage-Mode Control of PWM Buck Converter 470    12.1 Introduction 470    12.2 Properties of Negative Feedback 471    12.3 Stability 474    12.4 Single-Loop Control of PWM Buck Converter 475    12.5 Closed-Loop Small-Signal Model of Buck Converter 478    12.6 Pulse-Width Modulator 478    12.7 Feedback Network 483    12.8 Transfer Function of Buck Converter with Modulator and Feedback Network 486    12.9 Control Circuits 489    12.10 Closed-Loop Step Responses 511    12.11 Summary 518    References 519    Review Questions 519    Problems 520    13 Voltage-Mode Control of Boost Converter 521    13.1 Introduction 521    13.2 Circuit of Boost Converter with Voltage-Mode Control 521    13.3 Transfer Function of Modulator, Boost Converter Power Stage, and Feedback Network 523    13.4 Integral-Double-Lead Controller 527    13.5 Design of Integral-Double-Lead Controller 532    13.6 Loop Gain 536    13.7 Closed-Loop Control-to-Output Voltage Transfer Function 537    13.8 Closed-Loop Audio Susceptibility 539    13.9 Closed-Loop Input Impedance 539    13.10 Closed-Loop Output Impedance 542    13.11 Closed-Loop Step Responses 544    13.12 Closed-Loop DC Transfer Functions 549    13.13 Summary 552    References 552    Review Questions 552    Problems 553    14 Current-Mode Control 554    14.1 Introduction 554    14.2 Principle of Operation of PWM Converters with Peak CMC 555    14.3 Relationship Between Duty Cycle and Inductor-Current Slopes 559    14.4 Instability of Closed-Current Loop 560    14.5 Slope Compensation 564    14.6 Sample-and-Hold Effect on Current Loop 570    14.7 Closed-Loop Control Voltage-to-Inductor Current Transfer Function in s-Domain 580    14.8 Loop Gain of Current Loop 588    14.9 Gain-Crossover Frequency of Inner Loop 595    14.10 Phase Margin of Inner Loop 596    14.11 Maximum Duty Cycle for Converters Without Slope Compensation 598    14.12 Maximum Duty Cycle for Converters with Slope Compensation 600    14.13 Minimum Slope Compensation for Buck and Buck   Boost Converter 605    14.14 Minimum Slope Compensation for Boost Converter 607    14.15 Error Voltage-to-Duty Cycle Transfer Function 610    14.16 Closed-Loop Control Voltage-to-Duty Cycle Transfer Function of Current Loop 614    14.17 Alternative Representation of Current Loop 618    14.18 Current Loop with Disturbances 618    14.19 Voltage Loop of PWM Converters with Current-Mode Control 624    14.20 Feedforward Gains in PWM Converters with Current-Mode Control without Slope Compensation 631    14.21 Feedforward Gains in PWM Converters with Current-Mode Control and Slope Compensation 634    14.22 Control-to-Output Voltage Transfer Function of Inner Loop with Feedforward Gains 636    14.23 Audio-Susceptibility of Inner Loop with Feedforward Gains 637    14.24 Closed-Loop Transfer Functions with Feedforward Gains 638    14.25 Slope Compensation by Adding a Ramp to Inductor Current Waveform 638    14.26 Relationships for Constant-Frequency Current-Mode On-Time Control 639    14.27 Summary 639    References 640    Review Questions 644    Problems 644    14.28 Appendix: Sample-and-Hold Modeling 645    15 Current-Mode Control of Boost Converter 653    15.1 Introduction 653    15.2 Open-Loop Small-Signal Transfer Functions 653    15.3 Open-Loop Step Responses of Inductor Current 667    15.4 Closed-Current-Loop Transfer Functions 675    15.5 Closed-Voltage-Loop Transfer Functions 695    15.6 Closed-Loop Step Responses 706    15.7 Closed-Loop DC Transfer Functions 710    15.8 Summary 711    References 711    Review Questions 712    Problems 712    16 Open-Loop Small-Signal Characteristics of PWM Boost Converter for DCM 713    16.1 Introduction 713    16.2 Small-Signal Model of Boost Converter for DCM 713    16.3 Open-Loop Control-to-Output Transfer Function 716    16.4 Open-Loop Input-to-Output Voltage Transfer Function 719    16.5 Open-Loop Input Impedance 724    16.6 Open-Loop Output Impedance 725    16.7 Step Responses of Output Voltage of Boost Converter for DCM 728    16.8 Open-Loop Duty Cycle-to-Inductor Current Transfer Function 731    16.9 Open-Loop Input Voltage-to-Inductor Current Transfer Function 735    16.10 Open-Loop Output Current-to-Inductor Current Transfer Function 735    16.11 Step Responses of Inductor Current of Boost Converter for DCM 738    16.12 DC Characteristics of Boost Converter for DCM 742    16.13 Summary 745    References 745    Review Questions 746    Problems 746    17 Silicon and Silicon-Carbide Power Diodes 747    17.1 Introduction 747    17.2 Electronic Power Switches 747    17.3 Atom 748    17.4 Electron and Hole Effective Mass 749    17.5 Semiconductors 750    17.6 Intrinsic Semiconductors 751    17.7 Extrinsic Semiconductors 756    17.8 Wide Band Gap Semiconductors 762    17.9 Physical Structure of Junction Diodes 764    17.10 Static I   V Diode Characteristic 768    17.11 Breakdown Voltage of Junction Diodes 772    17.12 Capacitances of Junction Diodes 784    17.13 Reverse Recovery of pn Junction Diodes 789    17.14 Schottky Diodes 798    17.15 Solar Cells 806    17.16 Light-Emitting Diodes 809    17.17 SPICE Model of Diodes 810    17.18 Summary 811    References 815    Review Questions 816    Problems 817    18 Silicon and Silicon-Carbide Power MOSFETs 819    18.1 Introduction 819    18.2 Integrated MOSFETs 819    18.3 Physical Structure of Power MOSFETs 819    18.4 Principle of Operation of Power MOSFETs 824    18.5 Derivation of Power MOSFET Characteristics 826    18.6 Power MOSFET Characteristics 831    18.7 Mobility of Charge Carriers 833    18.8 Short-Channel Effects 846    18.9 Aspect Ratio of Power MOSFETs 848    18.10 Breakdown Voltage of Power MOSFETs 850    18.11 Gate Oxide Breakdown Voltage of Power MOSFETs 852    18.12 Specific On-Resistance 852    18.13 Figures-of-Merit of Semiconductors 855    18.14 On-Resistance of Power MOSFETs 857    18.15 Capacitances of Power MOSFETs 862    18.16 Switching Waveforms 875    18.17 SPICE Model of Power MOSFETs 877    18.18 IGBTs 879    18.19 Heat Sinks 880    18.20 Summary 886    References 888    Review Questions 888    Problems 889    19 Electromagnetic Compatibility 891    19.1 Introduction 891    19.2 Definition of EMI 891    19.3 Definition of EMC 892    19.4 EMI Immunity 892    19.5 EMI Susceptibility 893    19.6 Classification of EMI 893    19.7 Sources of EMI 895    19.8 Safety Standards 896    19.9 EMC Standards 896    19.10 Near Field and Far Field 897    19.11 Techniques of EMI Reduction 897    19.12 Insertion Loss 898    19.13 EMI Filters 898    19.14 Feed-Through Capacitors 900    19.15 EMI Shielding 900    19.16 Interconnections 902    19.17 Summary 903    References 903    Review Questions 903    Problem 904    A Introduction to SPICE 907    B Introduction to MATLAB(R) 910    C Physical Constants 915    Answers to Problems 917    Index 925