DOCSLIB.ORG

Feedback Amplifiers：Theory and Design.Pdf

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Feedback Amplifiers：Theory and Design.Pdf FEEDBACK AMPLIFIERS This page intentionally left blank Feedback Amplifiers Theory and Design by Gaetano Palumbo University of Catania and Salvatore Pennisi University of Catania KLUWER ACADEMIC PUBLISHERS NEW YORK, BOSTON, DORDRECHT, LONDON, MOSCOW eBook ISBN: 0-306-48042-5 Print ISBN: 0-7923-7643-9 ©2003 Kluwer Academic Publishers New York, Boston, Dordrecht, London, Moscow Print ©2002 Kluwer Academic Publishers Dordrecht All rights reserved No part of this eBook may be reproduced or transmitted in any form or by any means, electronic, mechanical, recording, or otherwise, without written consent from the Publisher Created in the United States of America Visit Kluwer Online at: http://kluweronline.com and Kluwer's eBookstore at: http://ebooks.kluweronline.com To our families: Michela and Francesca Stefania, Francesco, and Valeria CONTENTS ACKNOWLEDGEMENTS xi PREFACE xiii 1. INTRODUCTION TO DEVICE MODELING 1 (by Gianluca Giustolisi) 1.1 DOPED SILICON 1 1.2 DIODES 2 1.2.1 Reverse Bias Condition 5 1.2.2 Graded Junctions 6 1.2.3 Forward Bias Condition 7 1.2.4 Diode Small Signal Model 9 1.3 MOS TRANSISTORS 9 1.3.1 Basic Operation 10 1.3.2 Triode or Linear Region 12 1.3.3 Saturation or Active Region 14 1.3.4 Body Effect 15 1.3.5 p-channel Transistors 16 1.3.6 Saturation Region Small Signal Model 16 1.3.7 Triode Region Small Signal Model 21 1.3.8 Cutoff Region Small Signal Model 23 1.3.9 Second Order Effects in MOSFET Modeling 24 1.3.10Sub-threshold Region 28 1.4 BIPOLAR-JUNCTIONTRANSISTORS 29 1.4.1 Basic Operation 31 1.4.2 Early Effect or Base Width Modulation 32 1.4.3 Saturation Region 33 1.4.4 Charge Stored in the Active Region 33 1.4.5 Active Region Small Signal Model 34 REFERENCES 36 2. SINGLE TRANSISTOR CONFIGURATIONS 37 2.1 THE GENERIC ACTIVE COMPONENT 37 2.2 AC SCHEMATIC DIAGRAM AND LINEAR ANALYSIS 39 2.3 COMMON X (EMITTER/SOURCE) CONFIGURATION 41 2.4 COMMON X WITH DEGENERATIVE RESISTANCE 42 2.5 COMMON Y (BASE/GATE) 48 2.6 COMMON Z (COLLECTOR/DRAIN) 51 2.7 FREQUENCY RESPONSE OF SINGLE TRANSISTOR 54 CONFIGURATIONS viii 2.7.1 Common X Configuration 55 2.7.2 Common X with a Degenerative Resistance 56 2.7.3 Common Y and Common Z Configurations 61 3. FEEDBACK 63 3.1 METHOD OF ANALYSIS OF FEEDBACK CIRCUITS 64 3.2 SIGNAL FLOW GRAPH ANALYSIS 67 3.3 THE ROSENSTARK METHOD 69 3.4 THE CHOMA METHOD 72 3.5 THE BLACKMAN THEOREM 74 4. STABILITY - FREQUENCY AND STEP RESPONSE 77 4.1 ONE-POLE FEEDBACK AMPLIFIERS 78 4.2 TWO-POLE FEEDBACK AMPLIFIERS 82 4.3 TWO-POLE FEEDBACK AMPLIFIERS WITH A POLE- 92 ZERO DOUBLET 4.4 THREE-POLE FEEDBACK AMPLIFIERS WITH REAL 97 POLES 4.5 THREE-POLE FEEDBACK AMPLIFIERS WITH A PAIR OF 98 COMPLEX AND CONJUGATE POLES 4.6 TWO-POLE FEEDBACK AMPLIFIERS WITH A ZERO 100 5. FREQUENCY COMPENSATION TECHNIQUES 103 5.1 DOMINANT-POLE COMPENSATION 104 5.2 MILLER (POLE-SPLITTING) COMPENSATION 106 5.3 COMPENSATION OF THE MILLER RHP ZERO 109 5.3.1 Nulling Resistor 110 5.3.2 Voltage Buffer 111 5.3.3 Current Buffer 114 5.4 NESTED MILLER COMPENSATION 116 5.4.1 General Features 116 5.4.2 RHP Cancellation with Nulling Resistors 120 5.5 REVERSED NESTEDMILLER COMPENSATION 126 5.5.1 General Features 126 5.5.2 RHP Cancellation with Nulling Resistors 130 5.5.3 RHP Cancellation with One Real Voltage Buffer 131 5.5.4 RHP Cancellation with One Real Current Buffer 134 6. FUNDAMENTAL FEEDBACK CONFIGURATIONS 137 6.1 SERIES-SHUNT AMPLIFIER 137 6.1.1 Series-shunt Amplifier with Buffer 146 6.2 SHUNT-SERIESAMPLIFIER 148 6.3 SHUNT-SHUNT AMPLIFIER 155 ix 6.4 SERIES-SERIES AMPLIFIER 158 6.5 A GENERAL VIEW OF SINGLE-LOOP AMPLIFIERS 162 6.6 FREQUENCY COMPENSATION OF THE FUNDAMENTAL 165 CONFIGURATIONS 6.6.1 Frequency Compensation of the Series-Shunt Amplifier 166 6.6.2 Frequency Compensation of the Shunt-Series Amplifier 169 6.6.3 Frequency Compensation of the Shunt- Shunt Amplifier 171 6.6.4 Frequency Compensation of the Series-Series Amplifier 172 7.HARMONIC DISTORTION 173 7.1 HARMONIC DISTORTION AT LOW FREQUENCY 176 7.1.1 Nonlinear Amplifier with Linear Feedback 176 7.1.2 Nonlinear Amplifier with Nonlinear Feedback 178 7.2 HARMONIC DISTORTION IN THE FREQUENCY DOMAIN 182 7.2.1 Open-loop Amplifiers 182 7.2.2 Closed-loop Amplifiers 185 7.3 HARMONIC DISTORTION AND COMPENSATION 191 7.3.1 Two-stage Amplifier with Dominant-Pole Compensation 191 7.3.2 Two-stage Amplifier with Miller Compensation 193 7.3.3 Single-stage Amplifiers 199 7.4 AN ALTERNATIVE FREQUENCY ANALYSIS 205 8. NOISE 207 8.1 BASIC CONCEPTS 207 8.2 EQUIVALENT INPUT NOISE GENERATORS 209 8.3 NOISE MODELS OF CIRCUIT COMPONENTS 212 8.4 EFFECT OF FEEDBACK 214 9. EXAMPLES OF FEEDBACK IN INTEGRATED CIRCUITS 221 9.1 THE OUTPUT RESISTANCE OF A DIFFERENTIAL 221 AMPLIFIER WITH CURRENT-MIRROR LOAD 9.2 THE WILSON CURRENT MIRROR 224 9.3 THE CASCODE CURRENT MIRROR 228 9.4 THE CURRENT FEEDBACK OPERATIONAL AMPLIFIER 229 AND ITS HIGH-LEVEL CHARACTERISTICS 9.5 TRANSISTOR-LEVEL ARCHITECTURE, SMALL-SIGNAL 232 MODEL, AND FREQUENCY COMPENSATION OF CFOAS 9.6 INTEGRATORS AND DIFFERENTIATORS WITH CFOAS 236 9.7 CFOA VERSUS VOA 238 x APPENDIX: FREQUENCY ANALYSIS OF RC NETWORKS 243 A.1 TRANSFER FUNCTION OF A GENERIC RCNETWORK 243 A.2 APPROXIMATED POLES 247 REFERENCES 251 ABOUT THE AUTHORS 263 xi ACKNOWLEDGEMENTS The authors wish to thank Massimo Alioto, Walter Aloisi and Rosario Mita for their help during the correction of the draft. A special thank is due to Professor John Choma jr., a scientific leader in feedback theory and feedback amplifiers, for his encouragement and inspiration in the development of this book. We would like to thank our families and parents for their endless support and interest in our careers. Gaetano Palumbo Salvatore Pennisi This page intentionally left blank xiii PREFACE Feedback circuits and their related properties have been extensively investigated since the early days of electronics. From the time scientific and industrial communities started talking about and working with active elements like vacuum tubes or transistors, until today, much literature and many scientific results have been published which reinforce the importance of feedback. Improved features have been implemented in integrated circuits, novel techniques of analysis have been proposed which deeply improve our understanding of the resulting layouts, and new design strategies have been developed to optimise performance. Nevertheless, the genuinely complex subject of feedback and its applications in analog electronics remain obscure even for the majority of graduate electronics students. To this end, the main focus of this book will be to provide the reader with a real and deep understanding of feedback and feedback amplifiers. Whenever possible and without any loss of generality, a simple and intuitive approach will be used to derive simple and compact equations useful in pencil-and-paper design. Complex analytical derivations will be used only when necessary to elucidate fundamental relationships. Consequently, the contents of the book have been kept to a reasonably accessible level. The book is written for use both by graduate and postgraduate students who are already familiar with electronic devices and circuits, and who want to extend their knowledge to cover all aspects of the analysis and design of analog feedback circuits/amplifiers. Although the material is presented in a formal and theoretical manner, much emphasis is devoted to a design perspective. Indeed, the book can become a valid reference for analog IC designers who wish to deal more deeply with feedback amplifier features and their related design strategies, which are often partially –or even incorrectly– presented in the open literature. For this purpose (and despite xiv maturity of the subject), novel formalisms, approaches, and results are described in this book. For instance, a generic small-signal model applicable to a variety of different transistor types operating in the active region is introduced. A new comprehensive approach for the frequency compensation of two-stage and three-stage amplifiers is adopted. Novel and insightful results are reported for harmonic distortion in the frequency domain. The outline of the text is as follows: Chapter 1 provides a brief introduction to the operating principles of Bipolar and MOS transistors together with their small-signal models. This chapter is an invited contribution by Dr. Ginaluca Giustolisi. A general small-signal model for transistors in the active region of operation is derived in Chapter 2. The resulting model helps the reader to acquire a uniform view of the designer’s tasks and sidesteps the impractical distinction traditionally practised between Bipolar and MOS devices. This model is then thoroughly utilised in the rest of the chapter and the book itself. The three basic single-transistor configurations, which are the common-emitter, common-collector, common-base, for the bipolar transistor and common source, common-drain, common-gate for the MOS transistor, are subsequently revisited. General relationships, for both these active components, valid at low and high frequencies are accordingly developed. Feedback is introduced in Chapter 3. Feedback features are discussed in detail with particular emphasis on achievable advantages (and corresponding disadvantages) from a circuit perspective. Moreover, after an overview of the numerous techniques proposed until now to analyse feedback circuits, the two techniques which are the most useful in the authors’ opinion are presented together with Blackman’s theorem which is concerned only with the impedance level change due to feedback.
Load more

Recommended publications
  • Low-Power Class-AB CMOS Voltage Feedback Current Operational Amplifier with Tunable Gain and Bandwidth
    This is the author's version of an article that has been published in this journal. Changes were made to this version by the publisher prior to publication. The final version of record is available at http://dx.doi.org/10.1109/TCSII.2014.2327390 Low-Power Class-AB CMOS Voltage Feedback Current Operational Amplifier with Tunable Gain and Bandwidth Fermin Esparza-Alfaro, Salvatore Pennisi, Senior Member, IEEE, Gaetano Palumbo, Fellow, IEEE and Antonio J. Lopez-Martin, Senior Member, IEEE COA [8]-[9] and Voltage Feedback Current Operational Abstract— A CMOS class AB variable gain Voltage Feedback Amplifier, VFCOA [10]-[12], respectively) are therefore Current Operational Amplifier (VFCOA) is presented. The required. Note that being COAs the CM counterpart of VOAs, implementation is based on class AB second generation current they are still bounded to the constant gain bandwidth product. conveyors and exploits an electronically tunable transistorized Instead, the VFCOA combines the constant bandwidth feedback network. The circuit combines high linearity, low power consumption and variable gain range from 0 to 24 dB with nearly property with the possibility of using non-linear resistors in constant bandwidth, tunable from 1 to 3 MHz. A prototype has the feedback loop without penalty in the overall circuit been fabricated in a 0.5-m technology and occupies a total area linearity [13], becoming a very interesting option for of 0.127 mm2. The VFCOA operates using a 3.3-V supply with designing wideband circuits. static power consumption of 280.5µW. Measurements for In this paper a novel low-power class AB VFCOA with maximum gain configuration show a dynamic range (1% transistorized feedback network is presented.
    [Show full text]
  • Feedback Amplifiers Theory and Design
    FEEDBACK AMPLIFIERS This page intentionally left blank Feedback Amplifiers Theory and Design by Gaetano Palumbo University of Catania and Salvatore Pennisi University of Catania KLUWER ACADEMIC PUBLISHERS NEW YORK, BOSTON, DORDRECHT, LONDON, MOSCOW eBook ISBN: 0-306-48042-5 Print ISBN: 0-7923-7643-9 ©2003 Kluwer Academic Publishers New York, Boston, Dordrecht, London, Moscow Print ©2002 Kluwer Academic Publishers Dordrecht All rights reserved No part of this eBook may be reproduced or transmitted in any form or by any means, electronic, mechanical, recording, or otherwise, without written consent from the Publisher Created in the United States of America Visit Kluwer Online at: http://kluweronline.com and Kluwer's eBookstore at: http://ebooks.kluweronline.com To our families: Michela and Francesca Stefania, Francesco, and Valeria CONTENTS ACKNOWLEDGEMENTS xi PREFACE xiii 1. INTRODUCTION TO DEVICE MODELING 1 (by Gianluca Giustolisi) 1.1 DOPED SILICON 1 1.2 DIODES 2 1.2.1 Reverse Bias Condition 5 1.2.2 Graded Junctions 6 1.2.3 Forward Bias Condition 7 1.2.4 Diode Small Signal Model 9 1.3 MOS TRANSISTORS 9 1.3.1 Basic Operation 10 1.3.2 Triode or Linear Region 12 1.3.3 Saturation or Active Region 14 1.3.4 Body Effect 15 1.3.5 p-channel Transistors 16 1.3.6 Saturation Region Small Signal Model 16 1.3.7 Triode Region Small Signal Model 21 1.3.8 Cutoff Region Small Signal Model 23 1.3.9 Second Order Effects in MOSFET Modeling 24 1.3.10Sub-threshold Region 28 1.4 BIPOLAR-JUNCTIONTRANSISTORS 29 1.4.1 Basic Operation 31 1.4.2 Early Effect or Base Width Modulation 32 1.4.3 Saturation Region 33 1.4.4 Charge Stored in the Active Region 33 1.4.5 Active Region Small Signal Model 34 REFERENCES 36 2.
    [Show full text]
  • Active Loads, Especially for Use in Inverter Circuits
    (19) TZZ ___T (11) EP 2 768 141 A1 (12) EUROPEAN PATENT APPLICATION (43) Date of publication: (51) Int Cl.: 20.08.2014 Bulletin 2014/34 H03K 19/0944 (2006.01) (21) Application number: 13155542.7 (22) Date of filing: 15.02.2013 (84) Designated Contracting States: (72) Inventors: AL AT BE BG CH CY CZ DE DK EE ES FI FR GB • Ganesan, Ramkumar GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO 64293 Darmstadt (DE) PL PT RO RS SE SI SK SM TR • Glesner, Prof. Dr. Manfred Designated Extension States: 64354 Reinheim (DE) BA ME (74) Representative: Stumpf, Peter (71) Applicant: Technische Universität Darmstadt c/o TransMIT GmbH 64285 Darmstadt (DE) Kerkrader Strasse 3 35394 Gießen (DE) (54) Active loads, especially for use in inverter circuits (57) The invention relates to actives loads, especially inventive way. The transistors may be PMOS or NMOS- for, but not limited to use in inverter circuits. The proposed organic transistors or transistors based on conventional active load comprises two transistors connected in an silicon technologies or others. EP 2 768 141 A1 Printed by Jouve, 75001 PARIS (FR) EP 2 768 141 A1 Description [0001] The invention relates to actives loads, especially for, but not limited to use in inverter circuits. The proposed active load uses an improved load structure containing two transistors connected to each other in an inventive way. 5 [0002] Organic circuits are PMOS only circuits due to inferior performance of NMOS transistors. Inverters are the fundamental circuit blocks to realize any functionality.
    [Show full text]
  • Active Loads in Amplifier Circuits This Worksheet and All Related Files Are
    Active loads in amplifier circuits This worksheet and all related files are licensed under the Creative Commons Attribution License, version 1.0. To view a copy of this license, visit http://creativecommons.org/licenses/by/1.0/, or send a letter to Creative Commons, 559 Nathan Abbott Way, Stanford, California 94305, USA. The terms and conditions of this license allow for free copying, distribution, and/or modification of all licensed works by the general public. Resources and methods for learning about these subjects (list a few here, in preparation for your research): 1 Questions Question 1 We know that the current in a series circuit may be calculated with this formula: E I = total Rtotal We also know that the voltage dropped across any single resistor in a series circuit may be calculated with this formula: ER = IR Combine these two formulae into one, in such a way that the I variable is eliminated, leaving only ER expressed in terms of Etotal, Rtotal, and R. file 00360 Question 2 Determine what will happen to the output voltage (Vout) and resistor R1’s current (IR1 ) in this circuit as the resistance of R2 is increased: R1 R2 Vout file 02654 2 Question 3 Suppose we were to compare the performance of two voltage divider circuits side-by-side. The circuit on the left has one variable resistor (R2), while the circuit on the right has two variable resistors (R1 and R2). The right-hand circuit’s resistors are ganged together in such a way that as one resistance increases, the other will decrease by the same amount, keeping the circuit’s total resistance constant: Rtotal varies Rtotal remains constant R1 R1 R2 Vout R2 Vout Knowing that the voltage output by a voltage divider is described by the following formula, determine which voltage divider circuit yields the greatest change in output voltage for a given change in R2’s resistance.
    [Show full text]
  • CMOS Operational Amplifiers
    5. CMOS Operational Amplifiers Analog Design for CMOS VLSI Systems Franco Maloberti Basic op-amp The ideal operational amplifier is a voltage controlled voltage source with infinite gain, infinite input impedance and zero output impedance. The op-amp is always used in feedback configuration. Analog Design for CMOS VLSI Systems 5. CMOS Operational Amplifiers Franco Maloberti 1 Typical feedback configuration Z4 Z1 + Z2 Z2 V0 = V2 V1 Z3 + Z4 Z1 Z1 Finite gain effect: Z4 Z1 + Z2 Z2 Z1 + Z2 V0 = V 2 V1 1 + Z + Z Z Z A Z 3 4 1 1 0 1 The error due to the finite gain is proportional to 1 / A0. This error must be smaller than the error due to impedance mismatch. Analog Design for CMOS VLSI Systems 5. CMOS Operational Amplifiers Franco Maloberti 2 OTA If impedances are implemented with capacitors and switches, after a transient, the load of the op-amp is made of pure capacitors. The behavior of the circuit does not depend on the output resistance of the op-amp and stages with high output resistance (operational transconductance amplifiers) can be used. Analog Design for CMOS VLSI Systems 5. CMOS Operational Amplifiers Franco Maloberti 3 Transient C V (0+ ) = V 1 i in C + C // C 1 0 + + C Vo (0 ) = Vi (0 ) C0 + C C + C V () = V 1 i in C C(1 g r ) 1 + + m 0 V o () = Vi () gm r0 C 0 g m Analog Design for CMOS VLSI Systems 5. CMOS Operational Amplifiers Franco Maloberti 4 Performance characteristics Actual op-amps deviate from the ideal behavior.
    [Show full text]
  • Operational Amplifiers and Linear Integrated Circuits, 3E
    OperationalOperational AmplifiersAmplifiers && LinearLinear IntegratedIntegrated Circuits:Circuits: TheoryTheory andand ApplicationApplication // 3E3E James ! Fiore 2 OperationalOperational AmplifiersAmplifiers && LinearLinear IntegratedIntegrated Circuits:Circuits: TheoryTheory andand ApplicationApplication by James M. Fiore Version 3.2.6, 07 May 2021 3 This Operational Amplifiers & Linear Integrated Circuits: Theory and Application, by James M. Fiore is copyrighted under the terms of a Creative Commons license: This work is freely redistributable for non-commercial use, share-alike with attribution Device datasheets and other product information are copyright by their respective owners Published by James M. Fiore via dissidents ISBN13: 978-1796856897 For more information or feedback, contact: James Fiore, Professor Electrical Engineering Technology Mohawk Valley Community College 1101 Sherman Drive Utica, NY 13501 [email protected] For the latest revisions, related titles, and links to low cost print versions, go to: www.mvcc.edu/jfiore or my mirror sites www.dissidents.com and www.jimfiore.org YouTube Channel: Electronics with Professor Fiore Cover art, Canadian Shield II, by the author 4 #reface Welcome to the third edition of this text! The first edition was written circa 1990 and was published by West Publishing. The title was then purchased by Delmar/Thomson/Cengage some years later and a new edition was written around 2000 (although it was never tagged as a second edition). That version added a companion laboratory manual. In the early 2000s the text went from hard cover to soft cover, and in early 2016, Cengage decided to revert the copyright back to me, the original and singular author. Having already produced a number of OER (Open Educational Resource) titles including a microcontroller text using the Arduino platform and numerous laboratory manuals covering DC circuits, AC circuits, Python programming and discrete electronic devices, it was an obvious decision to go the same route with this book.
    [Show full text]
  • Operational Amplifiers: Chapters
    OPERATIONAL AMPLIFIERS: Theory and Practice OPERATIONAL AMPLIFIERS Theory and Practice JAMES K. ROBERGE Massachusetts Institute of Technology JOHN WILEY & SONS, Inc. New York - Chichester - Brisbane - Toronto - Singapore To Nancy PREFACE The operational amplifier is responsible for a dramatic and continuing revolution in our approach to analog system design. The availability of high performance, inexpensive devices influences the entire spectrum of circuits and systems, ranging from simple, mass-produced circuits to highly sophisticated equipment designed for complex data collection or processing operations. At one end of this spectrum, modern operational amplifiers have lowered cost and improved performance; at the other end, they allow us to design and implement systems that were previously too complex for consideration. An appreciation of the importance of this component, gained primarily through research rather than academic experience, prompted me in 1969 to start a course at M.I.T. focusing on the operational amplifier. Initially the course, structured as part of an elective sequence in active devices, concentrated on the circuit techniques needed to realize operational ampli- fiers and on the application of these versatile elements. As the course evolved, it became apparent that the operational ampli- fier had a value beyond that of a circuit component; it was also an excellent instructional vehicle. This device supplied a reason for studying a collection of analytic and design techniques that were necessary for a thorough under- standing of operational amplifiers and were also important to the general area of active-circuit design. For example, if we study direct-coupled ampli- fiers in detail, with proper attention given to transistor-parameter variation with temperature, to loading, and to passive-component peculiarities, we can improve our approach to the design of a large class of circuits depen- dent on these concepts and also better appreciate operational amplifiers.
    [Show full text]