Switching Power Supply Design-Ocr-Abraham I Pressman.pdf

Switching

Power Supply

Abraham I. Pressman

President, Switchtronix Power, Inc.

Waban, Massachusefts

Second Edition

New York

San Francisco Washington, D.C.

Auckland

Bogota

Caracas

Lisbon London Madrid Mexico City Milan

Montreal New Delhi San Juan Singapore

Sydney Tokyo

Toronto

Library of Congress Cataloging-in-PublicationData

Pressman, Abraham I.

Switching power supply design / Abraham 1. F'ressman. - 2nd cd.

p. cm.

Tncludea index.

ISRN 0-07-052236-7

1. Switching power supplies. 2. Electmn~capparatus and

appliance-Power

supply. 3. Mrcroelectronics-Power

supply.

4. Electric current converters. I. Title.

TK7868.PtiP75 1998

621.381'04Lde21

97-31688

GIP

4 Division ~['l'htt McGrmu.ffiB hpnies z

McGraw -Hill

reserved. Printed in the United States of America. Except ag permitted

under the United States Copyright Act of 1976, no part of this publica-

tion may be reproduced or distributed in any form or by any means, or

stored in a data base or retrieval system, without the prior written per-

mis~ion of the publisher.

ISBN 0-07-052236-7

The sponsoring editor for this hook was Steve Chapman, the ediling

supervisor wlu: Scott Amerrnun, and ~JLP prduutton sripervisor was

Sherri Souffrnnw. It was set in Century Schonlh(~)k

hy Ron I'ainter of

McGrmw-Hill's Profe~siunnl Rook Group cornpositznn unif.

Printed and bound Ry R, R. Ronnelley & Sons Company.

McGraw-Hill books are available at special quantity discounts to use as

premiums and sales promotions, or for use in corporate training programs.

For more information, please write to the Director of Special Sales,

McGraw-Hill, Professional Publishing, Two Penn Plaza, New York, NY

101 21 -2298. Or contact your local bookstore.

This hook is printed un recycled, acid-free paper containing a

minimum of 501 recycled, de-inked fiber.

Information contained in th~s work has been obtained by The McGraw-

Hill Companies, Inc. ("McGraw-Hill") from sources bel~evedto be reli-

able. However, nelther McGraw-Hill nor its author3 guarantee the accu-

racy or cump1etenen.s of any ~nformatiunpublished herein and neither

McGraw-Hill nor its authors shall be responsible fur any errors, omis-

sions, or damages nrising out of use of this mnformation. This work is

puhlighed with the understanding that McGraw-Hill and its authors

are ~upplylng

information but am not attempting to render engineering

or other profess~onal~srvices.

If such services are required, the aasis-

hnce of an appropriate pr0fet;sinnal .should be sought.

Contents

Preface

xix

Part I Topologies

Chapter 1. Fundamental Switching Regulators-Buck,

Boost,

and Inverter Topologies

1.1 Introduction

1.2 Linear Regulators-Swtiching Regulator Ancestors

1.2.1 Basic operation-merits and drawbacks

1.2.2 Linear regulator drawbacks

1.2.3 Power dissipation in the series-pass transistor

1.2.4 Linear regulator efficiency versus output voltage

1.2.5 Linear regulators with PNP series-pass transistors

for lesser required headroom

1.3 "Buck" Switching Regulator Topology

1.3.1

Basic operation

1.3.2

Significant current waveforms in buck regulator

1.3.3

Buck regulator efficiency neglecting AC switching losses

1.3.4

Buck regulator efficiency including AC switching losses

Optimum switching frequency in buck regulator

1.3.5

1.3.6

Design relations-output

filter inductor selection

Design relations-output filter capacitor selection

1.3.7

1.3.8

DC-isolated, regulated voltage from a buck regulator

1.4

Boost Switching Regulator Topology

1.4.1

Basic operation

1.4.2

Quantitative relations-boost regulator

Discontinuous and continuous modes in boost regulator

1.4.3

1.4.4

Discontinuous-mode boost regulator design relations

Boost regulator applications and flyback comparison

1.4.5

Polarity Inverting Switching Regulator Topology

1.5.1

1.5

Basic operation

Design relations in polarity inverter

1.5.2

Reference

Contents

Chapter 2. Push-Pull and Forward Converter Topologies

2.1

lntroduction

2.2

Push-Pull Topology

2.2.1

Basic operation-masterislave

outputs

2.2.2 Slave line-load regulation

2.2.3 Slave absolute output voltage levels

2.2.4 Master output inductor minimum current limitations

2.2.5 Flux imbalance in push-pull topology

2.2.6 Indications of flux imbalance

2.2.7 Testing for flux imbalance

2.2.8 Coping with flux imbalance

2.2.9 Power transformer design relations

2.2.10 Primary, secondary peak and rms currents

2.2.11 Transistor voltage stress and leakage inductance

spikes

2.2.12 Power transistor losses

2.2.13 Output power and input voltage limitations in push-pull

topology

2.2.14 Output filter design relations

2.3

Forward Converter Topology

2.3.1 Basic operation

2.3.2 Design relations: outputiinput voltage, on time, turns

ratios

2.3.3 Slave output voltages

2.3.4 Secondary load, free-wheeling diode, and inductor

currents

2.3.5 Relations between primary current, output power,

and input voltage

2.3.6 Maximum off-voltage stress in power transistor

2.3.7 Practical input voltageioutput power limits

2.3.8 Forward converter with unequal power and reset

winding turns

2.3.9 Forward converter magnetics

2.3.10 Power transformer design relations

2.3.11 Output filter design relations

2.4

Double-Ended Forward Converter Topology

2.4.1

Basic operation

2.4.2

Design relations and transformer design

2.5

Interleaved Forward Converter Topology

2.5.1

Basic operation-merits,

drawbacks, and output power

limits

Transformer design relations

2.5.2

2.5.3

Output filter design

Chapter 3. Half- and Full-Bridge Converter Topologies

3.1

lntroduction

3.2

Half-Bridge Converter Topology

3.2.1 Basic operation

3.2.2 Half-bridge magnetics

3.2.3 Output filter calculations

3.2.4

Blocking capacitor to avoid flux imbalance

3.2.5

Half-bridge leakage inductance problems

3.2.6

Double-ended forward converter versus half bridge

Contenl

3.2.7

Practical output power limits in half bridge

3.3

Full-Bridge Converter Topology

3.3.1

Basic operation

3.3.2

Full-bridge magnetics

3.3.3

Output filter calculations

3.3.4

Transformer primary blocking capacitor

Chapter 4. Flyback Converter Topologies

4.1

lntroduction

4.2

Flyback Converter-Areas of Application

4.3

Discontinuous-Mode Flybacks-Basic

Operation

4.3.1

Relation between output voltage versus input voltage,

on time, output load

4.3.2

Design relations and sequential decision requirements

4.3.3

Flyback magnetics

4.3.4

Flyback disadvantages

Flybacks for 120- or 220-V-AC operation with no

doubler and full-wave rectifier switching

4.3.5

4.4

Continuous-Mode Flybacks-Basic

Operation

4.4.1

Discontinuous-mode to continuous-mode transition

4.4.2

Design relations-continuous-mode

flybacks

4.5

Interleaved Flybacks

4.5.1

Summation of secondary currents in interleaved

flybacks

4.6

Double-Ended Discontinuous-Mode Flyback

4.6.1

Area of application

4.6.2

Basic operation

4.6.3

Leakage inductance effect in double-ended flyback

References

Chapter 5. Current-Mode and Current-Fed Topologies

5.1

lntroduction

5.2

Current-Mode Advantages

5.2.1

Avoidance of flux imbalance in push-pull converters

5.2.2

Instantaneous correction against line voltage changes

without the delay in an error amplifier (voltage

feedforward characteristics)

5.2.3

Ease and simplicity of feedback-loop stabilization

5.2.4

Paralleling outputs

5.2.5

Improved load current regulation

5.3

Current-Mode versus Voltage-Mode Control Circuits

5.3.1

Voltage-mode control circuitry

5.3.2

Current-mode control circuitry

5.4

Detailed Explanation of Current-Mode Advantages

5.4.1

Line voltage regulation

5.4.2

Elimination of flux imbalance

5.4.3

Simplified loop stabilization resulting from elimination

of output inductor in small-signal analysis

5.4.4

Mechanism of load current regulation

5.5

Current-Mode Deficiencies and Problems

5.5.1

Constant peak versus constant average output inductor

problems

Plik z chomika:

Inne pliki z tego folderu:

Inne foldery tego chomika: