Using simple, accessible language to balance coverage of theoretical and practical aspects, DC Power Supplies: Power Management and Surge Protection for Power Electronic Systems details the essentials of power electronics circuits applicable to low-power systems, including modern portable devices A summary of underlying principles and essential design points, it compares academic research and industry publications and reviews DC power supply fundamentals, including linear and low-dropout regulators Content also addresses common switching regulator topologies, exploring resonant conversion approaches Coverage includes other important topics such as: • • • • • • Control aspects and control theory Digital control and control ICs used in switching regulators Power management and energy efficiency Overall power conversion stage and basic protection strategies for higher reliability Battery management and comparison of battery chemistries and charge/discharge management Surge and transient protection of circuits designed with modern semiconductors based on submicron dimension transistors This specialized design resource explores applicable fundamental elements of power sources, with numerous cited references and discussion of commercial components and manufacturers Regardless of their previous experience level, this information will greatly aid designers, researchers, and academics who study, design, and produce the viable new power sources needed to propel our modern electronic world K10499 ISBN: 978-0-4158-0247-5 90000 780415 802475 DC Power Supplies Power Management and Surge Protection for Power Electronic Systems As we increasingly use electronic devices to direct our daily lives, so grows our dependence on reliable energy sources to power them Because modern electronic systems demand steady, efficient, reliable DC voltage sources—often at a sub-1V level—commercial AC lines, batteries, and other common resources no longer suffice New technologies also require intricate techniques to protect against natural and manmade disasters Still, despite its importance, practical information on this critical subject remains hard to find Kularatna Electrical Engineering DC Power Supplies Power Management and Surge Protection for Power Electronic Systems Nihal Kularatna K10499.indb www.electronicbo.com DC Power Supplies Power Management and Surge Protection for Power Electronic Systems 16/11/11 7:36 PM This page intentionally left blank Nihal Kularatna www.electronicbo.com DC Power Supplies Power Management and Surge Protection for Power Electronic Systems Boca Raton London New York CRC Press is an imprint of the Taylor & Francis Group, an informa business K10499.indb 16/11/11 7:36 PM CRC Press Taylor & Francis Group 6000 Broken Sound Parkway NW, Suite 300 Boca Raton, FL 33487-2742 © 2012 by Taylor & Francis Group, LLC CRC Press is an imprint of Taylor & Francis Group, an Informa business No claim to original U.S Government works Version Date: 2011916 International Standard Book Number-13: 978-0-415-80248-2 (eBook - PDF) This book contains information obtained from authentic and highly regarded sources Reasonable efforts have been made to publish reliable data and information, but the author and publisher cannot assume responsibility for the validity of all materials or the consequences of their use The authors and publishers have attempted to trace the copyright holders of all material reproduced in this publication and apologize to copyright holders if permission to publish in this form has not been obtained If any copyright material has not been acknowledged please write and let us know so we may rectify in any future reprint Except as permitted under U.S Copyright Law, no part of this book may be reprinted, reproduced, transmitted, or utilized in any form by any electronic, mechanical, or other means, now known or hereafter invented, including photocopying, microfilming, and recording, or in any information storage or retrieval system, without written permission from the publishers For permission to photocopy or use material electronically from this work, please access www.copyright com (http://www.copyright.com/) or contact the Copyright Clearance Center, Inc (CCC), 222 Rosewood Drive, Danvers, MA 01923, 978-750-8400 CCC is a not-for-profit organization that provides licenses and registration for a variety of users For organizations that have been granted a photocopy license by the CCC, a separate system of payment has been arranged Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identification and explanation without intent to infringe Visit the Taylor & Francis Web site at http://www.taylorandfrancis.com and the CRC Press Web site at http://www.crcpress.com With loving thanks to my wife Priyani and daughters Dulsha and Malsha and their families, who tolerate my addiction to tech writing and electronics K10499.indb www.electronicbo.com This book is dedicated to Sir Arthur C Clarke (the scientist who predicted satellite communication in the year 1945) and Prof John Robinson Pierce (who named the transistor) … they inspired me … 16/11/11 7:36 PM This page intentionally left blank Preface xi Acknowledgments xiii About the Author xv Contributors xvii Review of Fundamentals Related to DC Power Supply Design and Linear Regulators 1.1 1.2 1.3 1.4 Introduction 1-1 Simple Unregulated DC Power Supply and Estimating the Essential Component Values 1-2 Linear Regulators 1-3 Low-Dropout Regulators 1-18 Switching Power Supply Topologies and Design Fundamentals 2.1 2.2 2.3 2.4 2.5 Introduction 2-1 Why Switch Modes: An Overall Approach 2-2 Basic Switch-Mode Power Supply Topologies 2-3 Applications and Industry-Favorite Configurations 2-33 A Few Design Examples and Guidelines 2-39 Power Semiconductors 3.1 3.2 3.3 3.4 3.5 3.6 3.7 Introduction 3-1 Power Diodes and Thyristors 3-2 Gate Turn-Off Thyristors 3-18 Bipolar Power Transistors .3-20 Power MOSFETs .3-28 Insulated Gate Bipolar Transistor (IGBT) 3-45 MOS-Controlled Thyristor (MCT) 3-50 www.electronicbo.com Contents Resonant Converters and Wireless Power Supplies 4.1 4.2 4.3 4.4 Introduction 4-1 Fundamentals of Resonant Converters 4-1 Resonant DC-DC Converters 4-5 Load Resonant Converters for Contactless Power Supplies 4-11 vii K10499.indb 16/11/11 7:36 PM viii K10499.indb Contents Control Loop Design of DC-to-DC Converters 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9 Introduction 5-1 Feedback Control and Frequency Response 5-1 Poles, Zeros, and S-Domain 5-2 Stability Using Bode Plots .5-3 Linear Regulators’ Feedback and Loop Stability 5-4 Stability 5-11 Feedback Loop and Stability of Switch-Mode Power Supplies 5-19 Digital Control 5-27 Control Modes of Switch-Mode Converters 5-33 Power Management 6.1 6.2 6.3 6.4 6.5 Introduction 6-1 Design Approaches and Specifications 6-1 Specifying DC Power Supply Requirements 6-13 Loading Considerations 6-18 Powering High-Power Processors and ASICs 6-20 Off-the-Line Switching Power Supplies Introduction 7-1 Building Blocks of a Typical Off-the-Line Switching Power Supply 7-1 Rectifier Section 7-2 Popular Transformer-Isolated Configurations for Off-the-Line Power Supplies and Industry Approaches 7-7 7.5 Magnetic Components 7-11 7.6 Output Blocks 7-18 7.7 Efficiency Improvements and Synchronous Rectification 7-21 7.8 EMI Reduction 7-25 7.9 Power Supply Protection 7-28 7.10 Age-Related Aspects 7-35 7.11 Testing of Power Supplies 7-36 7.1 7.2 7.3 7.4 Rechargeable Batteries and Their Management 8.1 8.2 8.3 8.4 8.5 8.6 8.7 8.8 8.9 8.10 8.11 8.12 8.13 Introduction 8-1 Battery Terminology 8-2 Battery Technologies: An Overview 8-5 Lead-Acid Batteries 8-8 Nickel Cadmium (NiCd) Batteries 8-13 Nickel Metal Hydride Batteries 8-16 Lithium-Based Rechargeable Batteries .8-18 Reusable Alkaline Batteries 8-22 Zn-Air Batteries 8-24 Battery Management 8-25 Battery Communication and Related Standards .8-47 Battery Safety 8-49 Future .8-51 16/11/11 7:36 PM ix Contents Protection of Systems from Surges and Transients 9.1 9.2 9.3 9.4 9.5 Introduction 9-1 Types of Disturbances and Power Quality Issues 9-2 Principles of Surge Protection Techniques 9-9 Surge Protection Standards and Practices 9-16 Practical Design Considerations 9-26 Appendix A AppendixA-1 Appendix B AppendixB-1 www.electronicbo.com Index Index-1 K10499.indb 16/11/11 7:36 PM Appendix B-3 Appendix B TS ID TON Q1 t TS – TON ICR1 t ∆IL1 t V1 t Figure B.4 Waveforms (For the case of both inductor current being positive only) Appendix B2 Boost Converter Details Ideal Peak Drain Average Transfer Peak Drain Voltage Diode Function Current (IDMAX) (VDS) Currents 1− D K10499.indb I DMAX = VDS = ∆I L1 I RL + − D VO + VD Diode Reverse voltage (VRM) Advantages ICR1 = I RL VRM = Vo High efficiency Simple No transformer Low-input ripple current Disadvantages Typical Efficiency No isolation High peak drain current Regulator loop hard to stabilize High-output ripple Unable to control short-circuit current 80% www.electronicbo.com IL1 16/11/11 7:41 PM Appendix B-4 Appendix B B.3 Buck-Boost Converter ID Q1 CR1 + IL1 VIN – – L1 + C1 RL Vo IRL – + Figure B.5 Basic configuration TS ID Q1 TON ICR1 ∆IL1 IL1 t t t V1 t –(Vc+Vo) Figure B.6 Waveforms K10499.indb 16/11/11 7:41 PM Appendix B-5 Appendix B Appendix B3 Buck-Boost converter details −D 1− D I DMAX = VDS = I RL − D VIN + VO + VD + ICR1 = I RL VRM = Vo + VIN Typical Disadvantages Efficiency Advantages • Voltage inversion • Simple • No isolation • High side switch required • Regulator loop hard to stabilize • High output ripple • High input ripple current ∆I L1 B.4 SEPIC Converter + I1 L1 C1 VIN ID – CR1 L2 C2 + – IRL RL + VO – 80% www.electronicbo.com Diode Ideal Average Reverse Transfer Peak Drain Peak Drain Diode Voltage Function Current (IDMAX) Voltage (VDS) Currents (VRM) Figure B.7 Basic configuration K10499.indb 16/11/11 7:41 PM Appendix B-6 Appendix B ID TS TON t ICR1 IL1 IL2 t ∆IL1 t ∆IL2 t VDS t Figure B.8 Waveforms Appendix B3 SEPIC Converter Details Ideal Transfer Peak Drain Peak Drain Function Current (IDMAX) Voltage(VDS) D 1− D I DMAX = VDS = I1 + I RL + VIN + VO + VD ∆I L1 + ∆I L1 K10499.indb Average Diode Currents Diode Reverse Voltage (VRM) ICR1 = I RL VRM = Vo + VIN Advantages Low-input ripple current Buck and boost with no inversion No transformer Capacitive isolation against a switch failure Disadvantages Typical Efficiency No isolation Switch has high RMS/ peak currents (limits power) Capacitors have high ripple currents (low ESR needed) High-output ripple Loop stabilization difficult 16/11/11 7:41 PM Appendix B-7 Appendix B B.5 Forward Convertor CR2 V2 + N3 ID N2 C1 CR3 V1 IRL + RL – VO Q1 – – Figure B.9 Basic configuration VIN (N2/N1) V1 TON TS ICR2 t t ICR3 IL1 VIN (N2/N3) ∆IL1 t www.electronicbo.com VIN + IL1 CR1 N1 L1 t V2 VIN (N2/N1) – VD t Figure B.10 Waveforms K10499.indb 16/11/11 7:41 PM Appendix B-8 Appendix B Appendix B5 Forward Converter Details Ideal Transfer Function N2 D N1 Diode Reverse Voltage (VRM) Peak DrainCurrent (IDMAX) Peak Drain Voltage (VDS) Average Diode Currents I DMAX = VDS = ICR1 = VCR1 = D IˆMAG 2 N VIN + N1 ICR = VCR = I RL (D ) ICR = N VIN N3 I RL (1 − D ) VCR = N2 ∆I I RL + L1 VIN + N1 N1 N3 ∧ + I MAG IˆMAG Peak magnetizing current Advantages Drain current reduced by ratio N2/N1 Lowoutput ripple N VIN N1 Disadvantages Typical Efficiency Poor transformer utilization Poor transient response Transformer design critical Transformer reset limits D Switch requires high-voltage capability High-input ripple current B.6 Fly Back Converter CR1 + N1 VIN + IRL N2 V1 ID C1 + – RL VO Q1 – – Figure B.11 Basic configuration K10499.indb 16/11/11 7:41 PM Appendix B-9 Appendix B TON TS VDS t ID Q1 t ICR1 IL1 t VIN (N2/N1) V1 VO + VD t Figure B.12 Waveforms Appendix B6 Flyback Converter Details Ideal Transfer Function N2 D N1 1− D Peak Drain Current (IDMAX) I DMAX = VDS = VIN + N I RL N1 − D N2 N (VOUT + VD ) + K10499.indb Peak Drain Voltage(VDS) ∆I L1 Average Diode Currents Diode Reverse Voltage (VRM) ICR1 = I RL VCR1 = N VIN N1 Advantages Drain current reduced by ratio N2/N1 Low parts count Isolated output No secondary inductors Disadvantages Typical Efficiency Poor 80% transformer utilization Transformer stores energy High-output ripple current CR1 requires fast recovery www.electronicbo.com t ∆IL1 16/11/11 7:41 PM Appendix B-10 Appendix B B.7 Push-Pull Topology + T1 (??1) ID1 CR1 N1 N2 N1 N2 Q1 CR2 ID2 VIN L1 + Q2 C1 – RL IRL + VO – – Figure B.13 Basic configuration ID Q1 ID Q2 ICR1 t Ton ICR2 t TS VDS Q1 VIN VIN VDS Q2 IL1 VIN VIN ∆IL1 t t t t Figure B.14 Waveforms K10499.indb 10 16/11/11 7:41 PM Appendix B-11 Appendix B Ideal Transfer Function N2 D N1 Peak Drain Voltage (VDS) Peak Drain Current (IDMAX) I DMAX = Diode Reverse Voltage (VRM) Average Diode Currents VDS = 2VIN N2 ∆I I RL + L1 N1 ICR1 = I RL ICR = I RL + IˆMAG VCR1 = VCR = N 2VIN N1 Advantages Good transformer utilization Drain current reduced as function of N2/N1 Good at low VIN values Low-output ripple current Disadvantages Typical Efficiency Cross conduction of Q1/Q2 possible High parts count Transformer design critical Q1/Q2 should be high-voltage capable High-input ripple current 75% B.8 Two Switch Forward Converter L1 CR3 + + ID Q1 VIN CR1 N1 CR2 – IRL N2 CR4 C1 RL VO ID Q2 www.electronicbo.com Appendix B7 Phush-Pull Converter Details – Figure B.15 Basic configuration K10499.indb 11 16/11/11 7:41 PM Appendix B-12 Appendix B VIN (N2/N1) V1 t (VIN + VD1) (N2/N1) ICR3 t ICR4 t ∆IL1 t VIN + VD1 VDS2 t Figure B.16 Waveforms Appendix B8 Two-Switch Forward Converter Details Ideal Transfer Function N2 D N1 K10499.indb 12 Peak Drain Current (IDMAX) Peak Drain Voltage (VDS) Average Diode Currents Diode Reverse Voltage (VRM) Advantages Drain current reduced by ICR = VCR = N2 ∆I VIN + VD1 turns ratio I RL + L1 Lossless N1 (for both V IN ˆ D snubber transistors) I MAG + IˆMAG VCR = VCR = recovers energy ICR = I RL (D ) N Drain voltage VIN ICR = I RL (1 − D ) is half that of N1 singleswitch forward converter Low-output ripple I DMAX = VDS = ICR1 = VCR1 = Disadvantages Typical Efficiency Poor transformer utilization High parts count High-side switch required Transformer reset limits D High-input ripple current 16/11/11 7:41 PM Appendix B-13 Appendix B B.9 Half Bridge Converter + C1 + – Q1 N1 CR1 ID C2 N2 + N2 CR3 – Q2 CR4 CR2 – L1 C3 + – IRL + RL VO – Figure B.17 Basic configuration ID Q1 ICR3 ID Q2 ton TS t t ICR4 t www.electronicbo.com VIN VDS Q1 t VDS Q2 t IL1 ∆IL1 t Figure B.18 Waveforms K10499.indb 13 16/11/11 7:41 PM Appendix B-14 Appendix B Appendix B9 Half-Bridge Converter Details Ideal Transfer Function N2 D N1 Peak Drain Current (IDMAX) I DMAX = Peak Drain Voltage (VDS) VDS = VIN N2 ∆I I RL + L1 N1 Average Diode Currents ICR = I RL ICR = I RL + IˆMAG Diode Reverse Voltage (VRM) VCR = VCR N = VIN N1 Disadvantages Advantages Typical Efficiency Poor transient 75% response High parts count High-side switch required High-input current ripple C1/C2 has high ripple current Cross conduction of Q1/Q2 possible Good transformer utilization Transistors rated at VIN Isolated output ID reduced as a ratio of N2/N1 High power output Low-output ripple current Zero voltage switching possible near D=1 B.10 Full Bridge Converter + ID ID CR1 CR3 Q3 Q1 N1 ID VIN ID CR2 Q2 N2 N2 2 CR5 CR6 Q4 CR4 – C1 + – + IRL RL VO – Figure B.19 Basic configuration K10499.indb 14 16/11/11 7:41 PM Appendix B-15 Appendix B ID Q1, Q4 ID Q2, Q3 ICR5 t t ICR6 VDS Q1, Q4 t ton t VDS Q2, Q3 t IL1 ∆IL1 t Figure B.20 Waveforms Appendix B10 Full-Bridge Converter Details Ideal Transfer Function N2 D N1 Peak Drain Current (IDMAX) I DMAX = N2 ∆I I RL + L1 N1 ∧ + I MAG K10499.indb 15 Peak Drain Voltage (VDS) VDS = VIN Average Diode Currents Diode Reverse Voltage(VRM) ICR5 = I RL VCR1 = VCR = VIN ICR = I RL VCR5 = VCR N = 2VIN N1 Advantages Nearly same as half bridge Disadvantages Typical Efficiency High parts 73% count High-side switch required High-input current ripple C1 has high ripple current Cross conduction of Q1/Q2 or Q3/Q possible www.electronicbo.com TS 16/11/11 7:41 PM This page intentionally left blank Kularatna Electrical Engineering Coverage includes other important topics such as: • • • • • • Control aspects and control theory Digital control and control ICs used in switching regulators Power management and energy efficiency Overall power conversion stage and basic protection strategies for higher reliability Battery management and comparison of battery chemistries and charge/discharge management Surge and transient protection of circuits designed with modern semiconductors based on submicron dimension transistors This specialized design resource explores applicable fundamental elements of power sources, with numerous cited references and discussion of commercial components and manufacturers Regardless of their previous experience level, this information will greatly aid designers, researchers, and academics who study, design, and produce the viable new power sources needed to propel our modern electronic world K10499 ISBN: 978-0-4158-0247-5 90000 780415 802475 www.electronicbo.com Using simple, accessible language to balance coverage of theoretical and practical aspects, DC Power Supplies: Power Management and Surge Protection for Power Electronic Systems details the essentials of power electronics circuits applicable to low-power systems, including modern portable devices A summary of underlying principles and essential design points, it compares academic research and industry publications and reviews DC power supply fundamentals, including linear and low-dropout regulators Content also addresses common switching regulator topologies, exploring resonant conversion approaches DC Power Supplies Power Management and Surge Protection for Power Electronic Systems As we increasingly use electronic devices to direct our daily lives, so grows our dependence on reliable energy sources to power them Because modern electronic systems demand steady, efficient, reliable DC voltage sources—often at a sub-1V level—commercial AC lines, batteries, and other common resources no longer suffice New technologies also require intricate techniques to protect against natural and manmade disasters Still, despite its importance, practical information on this critical subject remains hard to find DC Power Supplies Power Management and Surge Protection for Power Electronic Systems Nihal Kularatna ... www.electronicbo.com DC Power Supplies Power Management and Surge Protection for Power Electronic Systems 16/11/11 7:36 PM This page intentionally left blank Nihal Kularatna www.electronicbo.com DC Power Supplies. .. isolation are covered by the DC- DC converters followed by the unregulated DC power supply, direct rectification and smoothing are used One common example is the desktop computer power supplies (known... 6-1 Specifying DC Power Supply Requirements 6-13 Loading Considerations 6-18 Powering High -Power Processors and ASICs 6-20 Off-the-Line Switching Power Supplies Introduction