Calvin College - Engineering Department Analog Design Spring 2002 Engineering 332 Professor: Paulo F. Ribeiro, SB130 X6407, PRIBEIRO@CALVIN.EDU Textbook: Sedra / Smith, Microelectronic Circuits, Fourth Edition Lectures: 12:30-1:20PM (MWF) SB203 Laboratory (Wednesdays 1:30-4:20 PM) SB 136 and SB28 Course objectives To focus on the design of amplifiers, filters, oscillators, and converters with an emphasis on design. Topics covered Differential and Multistage Amplifiers, Frequency Response, Feedback, Output Stages, Analog Integrated Circuits (741), Filters and Tuned Amplifiers, Signal Generators. Class/laboratory schedule 2-3 lectures per week plus 3-hour laboratory. Contribution of course to meeting the professional component This course contributes primarily to the students' knowledge of engineering topics, and does provide design experience. Relationship of course to undergraduate degree program objectives This course primarily serves students in the department. The information below describes how the course contributes to the undergraduate program objectives. Mastery of specific technical design skills which are key to a wide range of electrical engineering applications. Mastery and critical evaluation of the use of computer aided simulation tools (SPICE) as an engineering design aid. Assessment of student progress toward course objectives Student's design skills is assessed primarily on detailed homework and design problems that involve the use of analytical and simulation tools such as PSPICE. Schedule Topics Chapter # of classes Differential and Multistage Amplifiers 6 6 Frequency Response 7 6 Feedback 8 6 Output Stages 9 6 Analog Integrated Circuits (741) 10 3 Filters and Tuned Amplifiers 11 3 Signal Generators 12 3 Design Part I: Chapters 6, 7 Design Part II: Chapters 8, 9, 10 Final Design: Chapter 11, 12 Spring Break March 9-18 Reading Recess April 16-17 Grading Design Part I Design Part II Labs Homework and Assignments Participation Final Design 20% 20% 15% 15% 10% 20% 100% Lab Schedule: Lab 1 – The BJT Differential Pair and Amplifications Lab 2 – Single-BJT Amplifiers at Low and High Frequencies Lab 3 – Principles of Feedback Using and Op-AMP Building Block Lab 4 – Basic Output-Stage Topologies Lab 5 – OP-AMP-RC Filter Topologies Lab 6 – Waveform Generators Extra Lab – Power Supply Basic Homework Assignments (Minimum List) Students are recommended to work out most of the problems in the back of each assigned chapter. Additional Interactive Examples from accompanying CD and design problems will also be required to be completed. Chapter 6 7 8 9 10 11 12 Problems 6.1, 6.5, 6.15, 6.19, 6.33, 6.42, 6.50, 6.70, 6.77, 6.87, 6.97, 6.113 7.1, 7.7, 7.11, 7.26, 7.28, 7.38, 7.57, 7.67, 7.73, 7.85 8.1, 8.8, 8.16, 8.20, 8.32, 8.48, 8.52, 8.71 9.4, 9.14, 9.18, 9.22, 9.32, 9.37, 9.45, 9.51 Detailed Analysis of the 741 OP-AMP Analysis of A Second Order Active Filter Analysis of the Wien Bridge Oscillator Observations Choose 10 Choose 8 All laboratory and homework exercises must be turned in on time for full credit. Late assignments will be assigned a penalty. Assignments more than one week late may be assigned a 50% penalty. Homework and lab assignments should be prepared electronically (Word, MathCAD, PSpice, MATLAB / Simulink, PSCAD, etc.). No handwritten assignments will be accepted. Differential and Multistage Amplifiers The most widely used circuit building block in analog integrated circuits. Use BJTs, MOSFETS and MESFETs (metal semiconductor FET – read 5.12 – Gallium Arsenide-GaAs Device). The BJT Differential Pair Connection to RC not essential to the operation Essential that Q1 and Q2 never enter saturation Use CD Implemented by a transistor circuit Different Modes of Operation Common voltage I/2 vE = vCM-VBE vC1 = VCC – ( ½) a I RC vC2 = VCC – ( ½) a I RC vC1 – vC2 = ? Vary vCM (what happens?) Rejects common-mode Differential pair with a common-mode input Different Modes of Operation vB1 = +1 Q1 Q2 vE = 0.3 Keeps Q2 off vC1 = VCC - a I RC vC2 = VCC Differential pair with a large differential input Different Modes of Operation Differential pair with a large differential input o opposite polarity To that of (b) Different Modes of Operation Differential pair with a small differential input Exercise 6.1 5 0.7 1 4.3 vC2 5 4.3 1 vC1 5 vE 0.7 vC2 0.7 Large-Signal Operation of the BJT Differential Pair Equations Which can be manipulated to yield iE1 ( vB1 vE) iE1 IS a e iE1 iE2 VT iE1 iE2 IS a e VT iE2 e ( vB2 vB1) VT 1 e ( vB1 vB2) ( vB2 vE) 1 VT iE1 iE2 iE2 1 iE1 iE2 ( vB1 vB2) 1 e VT 1I iE1 The collector currents can be obtained by multiplying the emitter currents by Alfa, which is ver close to unity ( vB2 vB1) VT 1 e 1I iE2 ( vB1 vB2) 1 e VT I Large-Signal Operation of the BJT Differential Pair Relatively small difference voltage vB1 – vB2 will cause the current I to flow almost entirely in one of the two transistors. 4.VT (~100mV) is sufficient to switch the current to one side of the pair. Small-Signal Operation The Collector Currents When vd is applied vd iC1 vB1 vB2 aI vd vBQ1 aI 2 VBE a I vd 2 VT 2 vd 2 iC1 aI 2 VBE 2 Interpretation: IC1 increases by ic and iC2 decreases by ic VT a I e iC1 gm IC 2 VT VT 2 VT vd vd e a I vd 2 VT 2 vd vd vd a I ic vBQ2 2 VT aI 1 e iC2 vd VT 1 e iC2 Multiplying by 2 VT e 2 VT Assuming vd<<2VT ~ a I 1 iC1 1 vd 2 VT 2 VT vd 1 vd 2 VT An Alternative Viewpoint Assume I to be ideal – its incremental resistance will be infinite and vd appears across a total resistance 2.re. re VT VT IE I ie 2 ic a ie a vd 2 re gm vd 2 A simple technique for determining the signal currents in a differential amplifier excited by a differential voltage signal vd; dc quantities are not shown. vd 2 re If emitter resistors are included ie vd 2 re 2 RE A differential amplifier with emitter resistances. Only signal quantities are shown (on color). Input Differential Resistance vd ib Rid ie 2 re 1 1 vd ib 1 2re 2 r This is the resistance-reflection rule; the resistance seen between the two bases is equal to the total resistance in the emitter circuit multiplied by the beta+1 Input Differential Resistance Rid 1 (2 re 2 RE) Differential Voltage Gain iC1 IC gm vd IC gm iC2 2 vC1 ( VCC IC RC) gm RC vd vC2 ( VCC IC RC) gm RC vd Ad Ad vc1 vc2 vd 2 2 gm RC a ( 2RC) ( 2 re 2 RE) RC ~ re RE The voltage gain is equal to the ratio of the total resistance in the collector circuit (2RC) to the total resistance in the emitter circuit (2re+2RE) vd 2 IC aI 2 Equivalence of the Differential Amp. To a Common-Emitter Amp. Differential amplifier fed in a complementary manner (push-pull or balanced) Base of Q1 raised Based of Q2 lowered Equivalence of the differential amplifier (a) to the two common-emitter amplifiers in (b). This equivalence applies only for differential input signals. Either of the two common-emitter amplifiers in (b) can be used to evaluate the differential gain, input differential resistance, frequency response, and so on, of the differential amplifier. Equivalent Circuit Model of a Differential Half-Circuit RC ro Ad gm RC ro Common-Mode Gain Assuming symmetry Common-mode half-circuits vc1 vCM vc2 vCM Assuming non-symmetry vo RC RC 2 R RC v1 v2 vCM Ad ( v1 v2) Acm 2 v1 v2 2 2 R re vCM a RC 2 R a RC 2 R If output is taken single-endedly Acm and the differential gain Ad We can define CMRR Acm Acm a RC CMRR a RC 2 R Ad Acm Ad 1 2 gm RC CMRR gm R a1 Input Common-Mode Resistance Ricm r vCM vCM ro 2 . Ricm Ricm = Equivalent common-mode half-circuit Since the input common-mode resistance is usually very large, its value will be affected by the transistor resistances R0 and r Nehemiah (Chief-Engineer of Wall Reconstruction) God Calls Us to be agents: Of Peace and Reconciliation For Justice For the Flourishing of the Natural Creation For Beauty For Knowledge For the Growth of other people Example 6.1 – Class Discussion Example 6.3 a) vE b) gm c) iC d) vC e) vc1-vc2 f) gain at 1000Hz I 1 VCC 15 RC 10 a 1 vB1( t) 5 0.005 sin 2 1000 t vB2( t) 5 0.005 sin 2 1000 t vBE 0.7 at 1mA a) VBE 0.7 0.025 ln 0.5 1 vE 5 VBE VBE 0.683 vE 4.317 b) gm IC gm 20 VT c) iC1( t) 0.5 gm 0.005 sin 2 1000 t iC2( t) 0.5 gm 0.005 sin 2 1000 t 0.6 iC1( t ) 0.5 iC2( t ) 0.4 0.3 0 0.001 0.002 0.003 t 0.004 0.005 d) vC1( t ) ( VCC IC RC) 0.1 RC sin 2 1000 t vC2( t ) ( VCC IC RC) 0.1 RC sin 2 1000 t 11 vC1( t ) vC2( t ) 10 9 0 0.001 0.002 0.003 0.004 0.005 0.003 0.004 0.005 t e) 2 vC2( t ) vC1( t ) 0 2 0 0.001 0.002 t Example 6.4 100 Delta_RC 0.02 Delta_IS 0.1 Delta_ 0.1 I 100 From Eq. 6.55 2 Delta_RC Delta_IS VOS VT RC IS 2 2 VOS 25 ( 0.02) 0.1 IB I 2 1 Delta_ IOS IB 2 VOS 2.55 IB 0.495 A 4 IOS 4.95 10 50nA A Finally, brothers, whatever is true, wherever is noble, whatever is right, what ever is pure, whatever is lovely, whatever is admirable – if anything is excellent or praiseworthy – think about such things. Phil. 4:8 I gladly admit that we number among us men and women whose modesty, courtesy, fair-mindedness, patience in disputation and readiness to see an antagonist's point of view, are wholly admirable. I am fortunate to have known them. But we must also admit that we show as high percentage as any group whatever of bullies, paranoiacs, backbiters, mopes, milksops, etc.. The loutishness that turns every argument into a quarrel is really no rarer among us than among the sub-literate; the restless inferiority-complex (“stern to inflict” but not “stubborn to endure”) which bleeds at a touch but scratches like a wildcat is almost as common among us as among schoolgirls. CS Lewis. Biasing In BJT Integrated Circuits Many resistors, transistors and capacitors makes impossible to use conventional biasing methods Biasing in IC is based on the use of constant-current sources The Diode-Connected Transistor Shorting the base and the collector of a BJT results in a twoterminal device having an I-v characteristic identical ot the iE-vBE of the BJT. i i 1 1 i i Since the BJT is still in active mode (vCB=0 results in an active mode operation) the current I divides between base and collector according to the value of the BJT Beta. Thus, the BJT still operates as a transistor in the active mode. This is the reason the I-v characteristics of the resulting diode is identical to the iE-vBE relationship of the BJT Exercise 6.5 R incremental = r // (1/gm) // ro 1 r gm 1 r Rinc r r ro 1 gm 1 gm 1 gm r r ro 1 ro ro re ro re ro re Rinc 25 0.5 Rinc 50 The Current Mirror Io IO 1 IE IO IREF 2 IREF 1 1 2 1 IE Finite Beta and Early Effect IO 2 V O V EE V BE 1 2 VA 1 I REF Exercise 6.6 VEE 5 Rout VBE 0.7 IO at IREF 100 5 Rout 1 10 IREF at VO VB IREF 1 IREF 0.001 VA ro Rout 100 VO VEE VBE VO 4.3 4 IO 9.804 10 2 VO 5 IO5 IO 5 ( 4.3) Rout 3 IO5 1.073 10 A Simple Current Source I REF V CC V BE R Exercise 6.7 IO IREF 0.001 IREF VCC 5 100 neglect the effects ro and finite Beta R at VCC VBE IREF VO 3 R 4.3 10 IREF 1 2 VA 50 ro 3 IO VBE 0.7 VO VBE ro VA IREF 4 ro 5 10 3 IO 1.026 10 Get wisdom, get understanding; do not forget my words or swerve from them. Do not forsake wisdom, and she will protect you; love her, and she will watch over you. Wisdom is supreme; therefore get wisdom. Though it cost all you have, get understanding. Esteem her, and she will exalt you; embrace her, and she will honor you. She will set a garland of grace on your head and present you with a crown of splendor. Prov. 4:4-8 However, this impulse to pursue the intellectual life must be kept "pure and disinterested," for the alternative is to "come to love knowledge-our knowingmore than the thing known: to delight not in the exercise of our talents but in the fact that they are ours, or even in the reputation they bring us". We must not think Pride is something God forbids because He is offended at it, or that Humility is something He demands as due to His own dignity -- as if God Himself was proud. He is not in the least worried about His dignity. The point is, He wants you to know Him: wants to give you Himself. And He and you are two things of such a kind that if you really get into any kind of touch with Him you will, in fact, be humble -delightedly humble, feeling the infinite relief of having for once got rid of all the silly nonsense about your own dignity which has made you restless and unhappy all your life. He is trying to make you humble in order to make this moment possible: trying to take off a lot of silly, ugly, fancy-dress in which we have all got ourselves up and are strutting about like the little idiots we are. Current-Steering Circuits I REF V CC V EE V EB1 V BE2 R IC Circuits 2 power supplies IREF is generated in the branch of the diode-connected transistor Q1, resistor R, and the diode-connected transistor Q2. Generation of a number of cross currents. Exercise 6.9 Comparison With MOS Circuits 1 - The MOS mirror does not suffer from the finite Beta 2 – Ability to operate close to the power supply is an important issue on IC design 3 - Current Transfer: BJTs ~ relative areas; MOS ~ W/L 4 - VA lower for MOS Improved Current-Source Circuits IREF IO 2 I 1 2 E 1 1 IE IO IREF IREF 1 1 1 2 2 1 VCC VEB1 VBE3 R 2 2 The Wilson Current Mirror Output resistance equal ro 2 A factor greater the then simple Current source Disadvantage: reduced output swing. Observe that the voltage at the collector at Q3 has to be greater than the negative supply voltage by (vBB1 = VCEsat-3), which is about a volt. Exercise 6.10 2 1 2 1 2 I E 2 I E 1 1 2 I E I E I E IREF IO I E 1 IE 2 2 I E 1 2 1 2 1 2 1 IE IE 1 1 2 IO IE 2 2 IREF IO IREF IE ~ 1 1 2 2 Widlar Current Source It differs from the basic current mirror in an important way: a resistor RE is included in the emitter lead of Q2. Neglecting the base current we can write: IREF VB1 VT ln IS IO VB2 VT ln IS IREF VB1 VB2 VT ln IO VB1 VB2 IO RE IREF IO RE VT ln IO Example 6.2 Example 6.3 Multistage Amplifiers – Example 6.4 – pg. 552 Calculating 1st stage gain -- Assuming 100 V 100W re1 re 2 I TE .25 25 Model Eqs. on Pg. 263 re r gm ( VI CT ) ( I VT E ( 1 ) ) r 1 r 2 ( 1)( re ) 101 *100 10.1kW Rid r 1 r 2 20.2kW In the same manor Ri 2 r 4 r 5 Ri 2 2 ( 1) r 2 (101 25) 5.05kW Current sources for biasing amplifying stages By Justin Jansen Multistage Amplifiers – Example 6.4 – pg. 552 Calculating 1st stage gain Total collector resistance 1 Ri2 Total emitter resistance A1 vo 1 vid I C RC _ Total_ R I E RE _ Total_ R Ri 2 ||( R1 R2 ) re1 re 2 5.05kW||40 kW 200W 22.4 VV Multistage Amplifiers – Example 6.4 – pg. 552 Calculating 2nd stage gain Ri3 Ri 3 ( 1)( R4 re7 ) re 7 VT IC 25 1 25W Ri 3 101 (2.3kW 25W) 234.8kW re4 and re5 calc. before A2 R3 || Ri 3 re 4 re 5 3 kW||234.8 kW 50W 59.2 V V Potential gain is halved b/c converting to single-ended output Multistage Amplifiers – Example 6.4 – pg. 552 Calculating 3rd stage gain Purpose is to allow amplified signal to swing negatively re8 Ri4 25 5 5W Ri 4 ( 1)( re8 R6 ) 101(5 3000) 303.5kW A3 vo 3 vo 2 R5 || Ri 4 re 7 R4 15.7 kW||303.5 kW 2.325kW 6.24 VV Multistage Amplifiers – Example 6.4 – pg. 552 Calculating 3rd stage gain A4 vo vo 3 3000 3005 R6 re 8 R6 .998 VV Overall Gain A Output Resistance vo vid A1 A2 A3 A4 8513 VV Ro R6 || (re8 R5 1 ) 152W 1 Samuel 7:7-12 When the Philistines heard that Israel had assembled at Mizpah, the rulers of the Philistines came up to attack them. And when the Israelites heard of it, they were afraid because of the Philistines. [8] They said to Samuel, "Do not stop crying out to the Lord our God for us, that he may rescue us from the hand of the Philistines." [9] Then Samuel took a suckling lamb and offered it up as a whole burnt offering to the Lord. He cried out to the Lord on Israel's behalf, and the Lord answered him. [10] While Samuel was sacrificing the burnt offering, the Philistines drew near to engage Israel in battle. But that day the Lord thundered with loud thunder against the Philistines and threw them into such a panic that they were routed before the Israelites. [12] THEN SAMUEL TOOK A STONE AND SET IT UP BETWEEN MIZPAH AND SHEN. HE NAMED IT EBENEZER, SAYING, "THUS FAR HAS THE LORD HELPED US." "The only people who achieve much are those who want knowledge so badly that they seek it while the conditions are unfavorable. Favorable conditions never come." The BJT Differential Amplifier With Active Load vo g m v d Ro ro2 ro4 Ro ro2 ro2 ro4 ro Ro vo 2 vo g m ro vd 2 IC gm ro VT g m ro VA ro4 ro g m v d 2 VA IC IC 2 r I 2 constant for a given transitor VT I Ri ro Gm gm 2 VT The Cascode Configuration The Cascode Configuration How shall a young man be faultless in his way? By keeping to your words. With all my heart I seek you; let me not stray from your commands. Within my heart I treasure your promise, that I may not sin against you. Blessed are you, O Lord; teach me your statutes. With my lips I declare all the ordinances of your mouth. In the way of your decrees I rejoice, as much as in all riches. Ps 119: 9-14 Experience, the most brutal of teachers; but you learn, my God do you learn. C.S. Lewis BJT Single Stage Common-Emitter Amplifier MOSFET Operation MOS Differential Amplifiers – MOS Differential Pair MOS Differential Amplifiers – Offset Voltage MOS Differential Amplifiers – Current Mirrors Problem 6.1 RC 3000 at vBE 0.7 iC 0.0005 vE vCM vBE iC1 1 iC vC1 VCC iC1 RC iC 0.001 vCM 2 vBE 0.7 0.025 ln 0.5 1 vE 2.683 4 iC1 4.95 10 vC1 3.515 VCC 5 vBE 0.683 100 Problem 6.15 vd 0.1 ie re 25 vd 2 ( re RE) RE 100 4 3 iE1 1.4 10 iE2 IE ie iE2 6 10 vc1 ie RC vc1 2 vc2 vc1 vd RC 5000 ie 4 10 iE1 IE ie Ad IE 0.001 4 Ad 40 vc2 ie RC vc2 2 BJT Differential Amplifier Laboratory Purpose The purpose of this lab is to investigate the behavior of a BJT difference amplifier. The circuit’s behavior needs to be modeled with theoretical equations and a computer simulation. Comparison of laboratory results with theoretical and simulated results is required for the relative validity of the models. This lab also investigates the variation of differential and common mode gains using a Monte Carlo analysis. Procedure Construct the circuit in Figure 1 on PSpice and a Jameco JE26 Breadboard using a Hewlett-Packard 6205 Dual DC Power Supply as the voltage sources and an MPQ2222 Bipolar Junction Transistor (Q2N2222). Using a Keithley 169 Digital Multi-Meter measure the voltages across the resistors to determine the transistor base current and collector current. From these current values calculate . Figure 1) Circuit for testing transistor value Figure 2 Next construct the amplifier circuit shown in Figure 2. All transistors are MPQ2222 Bipolar Junction Transistors. Use PSpice to construct the circuit. Measure the DC values at the collector of Q1 and Q2. Do the measured values agree with theoretical ones. Measure the DC value at the emitter of Q1 and Q2. Do the measured value agree with the theoretical one. Indicate the inverting and noninverting output. Input an AC signal into Q1 of your circuit at frequencies . What is the single voltage gain of your circuit? Both inputs (Vin1 and Vin2) should be then grounded in order to determine the DC operating point of the amplifier. Bias point voltages are measured and then compared to the bias points produced by the PSpice simulation. Record DC bias point data. Use a Wavetek 190 Function Generator with a sinusoidal input voltage of amplitude 0.031 V and apply to one of the input terminals and the other terminal remained grounded, as shown in figure 2. Use a Tektronix TDS 360 Digital Oscilloscope and a Fluke 1900A Multi-Meter the output of the amplifier to observe input signal frequencies. Determine the corner frequency (3-dB point) of the output and compared with the corner frequency generated with an AC sweep in PSpice. Plot the PSpice AC sweep simulation. Next calculate the differential mode voltage gain, AV-dm, from the laboratory data and compare to the AV-dm predicted by the PSpice simulation and theoretical equations. Both inputs are tied together to create a common mode signal on the input terminals. The output voltage is then used to calculate the common mode voltage gain, AV-cm, and then compared to the AV-cm predicted by the PSpice simulation and theoretical equations. From these values the common mode rejection ratio (CMRR) should be calculated for each case. Finally, PSpice should be used to perform a Monte Carlo analysis of the circuit. The resistors were all given standard unbridged values and were allowed to vary uniformly within 5% of the nominal resistor value. The transistors should be given a nominal value (say 175) and allowed to vary uniformly to +/- 100. The variations of differential and common mode gains should be graphed on two histograms. Analysis / Questions What are the values of for the first transistor? (typical values of range from approximately 125 to 225) With the exception of the Monte Carlo analysis, all transistors were assumed to have this value in the PSpice simulations. All four transistors were contained within one integrated circuit so that hopefully there would be little change in values from one transistor to the next, making the previous assumption reasonably valid. How close are the measured DC bias points of the circuit to those predicted by the PSpice simulation? What is the reason for the small differences between measured and predicted voltages? • Can a truly thinking person be a Christian? • Does the Gospel conflict with scientific knowledge and modern discoveries in other fields? • How can Christians achieve intellectual / scientific integrity? Found in Faith-Lost in Matters of Learning and Intellectual Integrity. The supreme end of education is expert discernment in all things - - the power to tell the good from the bad, the genuine from the counterfeit, and to prefer the good and the genuine to the bad and the counterfeit. Samuel Johnson Independence / obedience, honesty, humility, fairness… Let integrity and uprightness preserve me. Psalms, 25,21 Exercises 6.17 An Active-Loaded CMOS Amplifier Exercise 6.19 Example 6.5 SPICE Simulation of a Multistage Amplifier Frequency Response S-Domain Analysis Poles and Zeros N 40 z1 7 3 jj jj 1 z2 0 i 0 N p1 3 3 jj p3 7 j 0 N p2 3 p4 0 2 jj e 10.1 i 0.4 j 10.1 j 0.4 i f ( e w) M i j [ ( e z1 w jj) ( e z2 w jj) ] ( e w jj p1) ( e w jj p2) ( p3 w jj e) ( e w jj p4) f e j i M Bode Plots Example 7.2 Teach me your way, O Lord, and I will walk in your truth; give me an undivided heart, that I may fear your name. Ps. 86:11 "As for you, my son Solomon, know the God of your father, and serve Him with a whole heart and a willing mind; for the LORD searches all hearts, and understands every intent of the thoughts. (1 Chr. 28:9) COOPERATIVE LEARNING Positive interdependence. Team members are obliged to rely on one another to achieve the goal. Individual accountability. All students in a group are held accountable for doing their share of the work and for mastery of all of the material to be learned. Face-to-face interaction. Although some of the group work may be parcelled out and done individually, some must be done interactively, with group members providing one another with feedback, challenging one another's conclusions and reasoning. Appropriate use of collaborative skills. Students are encouraged and helped to develop and practice trust-building, leadership, decision-making, communication, and conflict management skills. Group processing. Team members set group goals, periodically assess what they are doing well as a team, and identify changes they will make to function more effectively in the future. COOPERATIVE LEARNING "What is the main idea of...?" "What if...?" "How does...affect...?" "What is the meaning of...?" "Why is...important?" "What is a new example of...?" "Explain why...." "Explain how...." "How does...relate to what I've learned before?" "What conclusions can I draw about...? "What is the difference between ... and ...?" "How are ... and ... similar?" "How would I use ... to ...?" "What are the strengths and weaknesses of...?" Frequency Response Exercise 7.1 The Amplifier Transfer Function The Three Frequency Bands (AM, wl, wh, BW, GB) The Gain Function A(s) and the Low-Frequency Response A(s ) A M FL( s ) FH( s ) A(s ) AM A L( s ) A M FL( s ) A H( s ) A M FH( s ) L H L 2 2 P1 P2 2 2 2 Z1 2 Z2 this relationship can be extended to any number of poles and zeros one of the poles can be dominant and the expression is simplied Low-Frequency Response H 1 1 2 P1 1 2 P1 2 2 Z1 2 2 Z1 Becoming An Engineer Competence Responsibility Integrity Writing Speaking Pr. 1:7 Writing General Suggestions 1. Learn All You Can (Furnish Your Mind) 2. Think Hard About The Subject (Exercise Your Mind) (Interesting, Creative Ideas) 3. Avoid Distractions (Quiet Your Mind) 4. Take A Break (Refresh Your Mind) 5. Save Time For Reflection (Free Your Mind) 6. Associate With Creative People (Stimulate Your Mind) 7. Keep Writing In Your Log Book (Tune In To Your Mind) 8. Notice Your “Crazy” Ideas (Respect Your Mind) 9. Be Quick To Question Authority/Professor (Alert Your Mind) 10. Trust God (Surrender Your Mind) Graphics Creation, Fall and Redemption: A Controls Systems Perspective CREATION Word of God (Laws, Commands, Structure) Creation Providence FALL + REDEMPTION Cultural Mandate + Cosmos Human Life History, Culture Redemption + Unfolding Redeeming Creation Redeemed Creation + Consummation Language exists to communicate whatever it can communicate. Some things it communicates so badly that we never attempt to communicate them by words if any other medium is available. C.S. Lewis Mathematics Creation, Fall and Redemption: A Mathematical Perspective ( 0) God (Universe ) Creation (Universe ) dx. dy. dz ( Good ) ( God ' s... Will ) ( Evil ) Fall d ( Evil ) ( Sin ) dt ( Man ' s... Sins) Redemption ( Death ) ( Jesus' ... Suffereing... & ... Re surection ) ( Death ) ( Death ) ( Eternal... Life ) The reason that some intuitive minds are not mathematical is that they cannot at all turn their attention to the principles of mathematics. But the reason that mathematicians are not intuitive is that they do not see what is before them …since they are accustomed to the exact principles of mathematics… and are lost in matters of intuition where the principles do not allow of such arrangement. Blaise Pascal Using Short-Circuit and Open Circuit Times Constants For the Approximate Determination of L and H Open Circuit time Constants H 1 CiRio i Dominant Pole Exists Short Circuit time Constants L CiRis 1 i Example 7.5 - Study Low-Frequency Response of the Common-Source Amplifier Vg ( s ) Rin Vi( s ) Rin Rs s 1 CC1 Rin R highpass function Cc1 introduces a zero at zero frequency and a real pole at p1 P1 1 CC1 Rin R Low-Frequency Response of the Common-Source Amplifier Next Id ( s ) Vg ( s ) I( s ) 1 Zs gm g m Vg ( s ) Id ( s ) YS 1 1 ZS RS YS g m YS s CS s g m Vg ( s ) Id ( s ) 1 CS RS g 1 m R S s CS Z CS gm 1 CS RS introduces a zero at P2 ZS at infinite, which means Vo zero CS 1 RS 1 Rs 1 gm CS 1 RS g m Low-Frequency Response of the Common-Source Amplifier ro RD approximation is valid after Thevenin's theorem and some manipulation Vo ( s ) s Id ( s ) Parallel RD ro RL s P3 1 CC2 RL R r D o RD ro CC2 1 CC2 RL RD ro R r D o introduces a zero at zero freq. and a real pole a W P3 Low-Frequency Response of the Common-Source Amplifier A L( s ) AM Vo ( s ) Vi( s ) Rin A M s s Z s s P1 s P2 s P3 g m Parallel RD ro RL Rin R Low-Frequency Response of the Common-Source Amplifier Design of the Coupling Cc1 and Cc2 and Bypass Capacitors Cs To place the lower 3-db frequency wl at the specified value. Exercise 7.7 The frequency of the zero is given by eq. 7.37 Z 1 CS RS CS The frequency of the pole is given by eq. 7.38 gm p gm CS 1 RS Analysis of the Common-Emitter Amplifier Analysis of the Common-Emitter Amplifier A MOSFET common-source amplifier (a), and a BJT common-emitter amplifier (b). here, Vs and Rs represent the Thévenin equivalent of the circuit at the input side, including the output circuit of the preceding amplifier stage (if any) and the bias network of the transistor Q (if any). Similarly, RL represents the total resistance between the drain (the collector) and signal ground. Although signal ground at the source (emitter) is shown established by a large capacitor, this is not necessary, and the circuits can be used to represent, for instance, the differential half-circuit of a differential pair. (a) Equivalent circuit for analyzing the high-frequency response of the amplifier circuit of Fig. 7.15(a). Note that the MOSFET is replaced with its high-frequency equivalent-circuit. (b) A slightly simplified version of (a) by combining RL and ro into a single resistance R’L = RL//ro. Chapter 8 - Feedback 1 - Desensitize The Gain 2 - Reduce Nonlinear Distortions 3 - Reduce The Effect of Noise 4 – Control The Input And Output Impedances 5 – Extend The Bandwidth Of The Amplifier Chapter 8 – Feedback The General Feedback Structure A xs xi xf xo A 1 A feedabck factor loop gain amount of feedabck xo A xi xi xs xf xf xo Af xo A xs 1 A The General Feedback Structure Exercise 8.1 4 A f 10 A 10 a) b) Af c) Amount_Feedback 20 log 1 A Amount_Feedback 60 R1 R1 R2 A d) 1 A Vs 1 Vo A f Vs Vf Vo 1 given Vo 10 Vf 0.999 Vi Vs Vf 4 Vi 10 10 A Af 1 A e) Find R1 R1 R2 0.1 4 A 0.8 10 0.1 R2 R1 9 10 9.998 10 100 0.02 A f A 1 A A f 9.998 The General Feedback Structure Exercise 8.1 Some Properties of Negative Feedback Gain Desensitivity Af A 1 A deriving dAf dA (1 A ) dividing by 2 dAf 1 Af (1 A ) Af A 1 A dA A The percentage change in Af (due to variations in some circuit parameter) is smaller than the pecentage cahnge in A by the amount of feedback. For this reason the amount of feedback 1 A is also known as the desensitivity factor. Some Properties of Negative Feedback Bandwidth Extension Some Properties of Negative Feedback Noise Reduction, Reduction of Nonlinear Distortion The Four Basic Feedback Topologies The four basic feedback topologies: (a) voltage-sampling series-mixing (series-shunt) topology; (b) current-sampling shunt-mixing (shunt-series) topology; (c) current-sampling series-mixing (series-series) topology; (d) voltage-sampling shunt-mixing (shunt-shunt) topology.