Basics of Microelectronics II.


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2. Section 9 Cascode Stages and Current Mirrors. 9.1 Cascode Stage9.2 Current Mirrors. CH 9 Cascode Stages and Current Mirrors. 3. . Helped Output Impedances. CH 9 Cascode Stages and Current Mirrors. 4. Bipolar Cascode Stage. . CH 9 Cascode Stages and Current Mirrors. 5. Most extreme Bipolar Cascode Output Impedance.
Transcripts
Slide 1

Basics of Microelectronics II CH9 Cascode Stages and Current Mirrors CH10 Differential Amplifiers CH11 Frequency Response CH12 Feedback

Slide 2

Chapter 9 Cascode Stages and Current Mirrors 9.1 Cascode Stage 9.2 Current Mirrors

Slide 3

Boosted Output Impedances CH 9 Cascode Stages and Current Mirrors

Slide 4

Bipolar Cascode Stage CH 9 Cascode Stages and Current Mirrors

Slide 5

Maximum Bipolar Cascode Output Impedance The most extreme yield impedance of a bipolar cascode is limited by the ever-display r  amongst emitter and ground of Q 1 . CH 9 Cascode Stages and Current Mirrors

Slide 6

Example: Output Impedance Typically r  is littler than r O , so when all is said in done it is difficult to twofold the yield impedance by declining Q 2 with a resistor. CH 9 Cascode Stages and Current Mirrors

Slide 7

PNP Cascode Stage CH 9 Cascode Stages and Current Mirrors

Slide 8

Another Interpretation of Bipolar Cascode Instead of regarding cascode as Q 2 declining Q 1 , we can likewise consider it Q 1 stacking on top of Q 2 (current source) to help Q 2 \'s yield impedance. CH 9 Cascode Stages and Current Mirrors

Slide 9

False Cascodes When the emitter of Q 1 is associated with the emitter of Q 2 , it\'s no more a cascode since Q 2 turns into a diode-associated gadget rather than a present source. CH 9 Cascode Stages and Current Mirrors

Slide 10

MOS Cascode Stage CH 9 Cascode Stages and Current Mirrors

Slide 11

Another Interpretation of MOS Cascode Similar to its bipolar partner, MOS cascode can be considered as stacking a transistor on top of a present source. Not at all like bipolar cascode, the yield impedance is not constrained by . CH 9 Cascode Stages and Current Mirrors

Slide 12

PMOS Cascode Stage CH 9 Cascode Stages and Current Mirrors

Slide 13

Example: Parasitic Resistance R P will bring down the yield impedance, since its parallel mix with r O1 will dependably be lower than r O1 . CH 9 Cascode Stages and Current Mirrors

Slide 14

Short-Circuit Transconductance The short out transconductance of a circuit measures its quality in changing over information voltage to yield current. CH 9 Cascode Stages and Current Mirrors

Slide 15

Transconductance Example CH 9 Cascode Stages and Current Mirrors

Slide 16

Derivation of Voltage Gain By speaking to a straight circuit with its Norton identical, the relationship between V out and V in can be communicated by the result of G m and R out . CH 9 Cascode Stages and Current Mirrors

Slide 17

Example: Voltage Gain CH 9 Cascode Stages and Current Mirrors

Slide 18

Comparison between Bipolar Cascode and CE Stage Since the yield impedance of bipolar cascode is higher than that of the CE arrange, we would anticipate that its voltage addition will be higher also. CH 9 Cascode Stages and Current Mirrors

Slide 19

Voltage Gain of Bipolar Cascode Amplifier Since r O is much bigger than 1/g m , the majority of I C,Q1 streams into the diode-associated Q 2 . Utilizing R out as some time recently, A V is effectively figured. CH 9 Cascode Stages and Current Mirrors

Slide 20

Alternate View of Cascode Amplifier A bipolar cascode speaker is additionally a CE arrange in arrangement with a CB stage. CH 9 Cascode Stages and Current Mirrors

Slide 21

Practical Cascode Stage Since no present source can be perfect, the yield impedance drops. CH 9 Cascode Stages and Current Mirrors

Slide 22

Improved Cascode Stage with a specific end goal to protect the high yield impedance, a cascode PNP current source is utilized. CH 9 Cascode Stages and Current Mirrors

Slide 23

MOS Cascode Amplifier CH 9 Cascode Stages and Current Mirrors

Slide 24

Improved MOS Cascode Amplifier Similar to its bipolar partner, the yield impedance of a MOS cascode intensifier can be enhanced by utilizing a PMOS cascode current source. CH 9 Cascode Stages and Current Mirrors

Slide 25

Temperature and Supply Dependence of Bias Current Since V T , I S ,  n , and V TH all rely on upon temperature, I 1 for both bipolar and MOS relies on upon temperature and supply. CH 9 Cascode Stages and Current Mirrors

Slide 26

Concept of Current Mirror The inspiration driving a present mirror is to sense the current from a "brilliant current source" and copy this "brilliant current" to different areas. CH 9 Cascode Stages and Current Mirrors

Slide 27

Bipolar Current Mirror Circuitry The diode-associated Q REF delivers a yield voltage V 1 that powers I copy1 = I REF , if Q 1 = Q REF . CH 9 Cascode Stages and Current Mirrors

Slide 28

Bad Current Mirror Example I Without shorting the gatherer and base of Q REF together, there won\'t be a way for the base streams to stream, thusly, I duplicate is zero. CH 9 Cascode Stages and Current Mirrors

Slide 29

Bad Current Mirror Example II Although a way for base streams exists, this system of biasing is no superior to anything resistive divider. CH 9 Cascode Stages and Current Mirrors

Slide 30

Multiple Copies of I REF Multiple duplicates of I REF can be created at various areas by essentially applying the possibility of current mirror to more transistors. CH 9 Cascode Stages and Current Mirrors

Slide 31

Current Scaling By scaling the emitter zone of Q j n times as for Q REF , I copy,j is likewise n times bigger than I REF . This is proportional to putting n unit-size transistors in parallel. CH 9 Cascode Stages and Current Mirrors

Slide 32

Example: Scaled Current CH 9 Cascode Stages and Current Mirrors

Slide 33

Fractional Scaling A small amount of I REF can be made on Q 1 by scaling up the emitter range of Q REF . CH 9 Cascode Stages and Current Mirrors

Slide 34

Example: Different Mirroring Ratio Using the possibility of current scaling and fragmentary scaling, I copy2 is 0.5mA and I copy1 is 0.05mA individually. All originating from a wellspring of 0.2mA. CH 9 Cascode Stages and Current Mirrors

Slide 35

Mirroring Error Due to Base Currents CH 9 Cascode Stages and Current Mirrors

Slide 36

Improved Mirroring Accuracy Because of Q F , the base streams of Q REF and Q 1 are for the most part supplied by Q F as opposed to I REF . Reflecting blunder is decreased  times. CH 9 Cascode Stages and Current Mirrors

Slide 37

Example: Different Mirroring Ratio Accuracy CH 9 Cascode Stages and Current Mirrors

Slide 38

PNP Current Mirror PNP current mirror is utilized as a present source burden to a NPN enhancer stage. CH 9 Cascode Stages and Current Mirrors

Slide 39

Generation of I REF for PNP Current Mirror CH 9 Cascode Stages and Current Mirrors

Slide 40

Example: Current Mirror with Discrete Devices Let Q REF and Q 1 be discrete NPN gadgets. I REF and I copy1 can change in huge extent because of I S crisscross. CH 9 Cascode Stages and Current Mirrors

Slide 41

MOS Current Mirror The same idea of current mirror can be connected to MOS transistors too. CH 9 Cascode Stages and Current Mirrors

Slide 42

Bad MOS Current Mirror Example This is not a present mirror since the relationship between V X and I REF is not unmistakably characterized. The best way to obviously characterize V X with I REF is to utilize a diode-associated MOS since it gives square-law I-V relationship. CH 9 Cascode Stages and Current Mirrors

Slide 43

Example: Current Scaling Similar to their bipolar partner, MOS current mirrors can likewise scale I REF up or down (I 1 = 0.2mA, I 2 = 0.5mA). CH 9 Cascode Stages and Current Mirrors

Slide 44

CMOS Current Mirror joining NMOS and PMOS to create CMOS current mirror is appeared previously. CH 9 Cascode Stages and Current Mirrors

Slide 45

Chapter 10 Differential Amplifiers 10.1 General Considerations 10.2 Bipolar Differential Pair 10.3 MOS Differential Pair 10.4 Cascode Differential Amplifiers 10.5 Common-Mode Rejection 10.6 Differential Pair with Active Load

Slide 46

Audio Amplifier Example A sound enhancer is built over that goes up against a redressed AC voltage as its supply and intensifies a sound sign from a mouthpiece. CH 10 Differential Amplifiers

Slide 47

"Murmuring" Noise in Audio Amplifier Example However, V CC contains a swell from amendment that breaks to the yield and is seen as a "murmuring" commotion by the client. CH 10 Differential Amplifiers

Slide 48

Supply Ripple Rejection Since both hub X and Y contain the swell, their distinction will be free of swell. CH 10 Differential Amplifiers

Slide 49

Ripple-Free Differential Output Since the sign is taken as a contrast between two hubs, an intensifier that detects differential signs is required. CH 10 Differential Amplifiers

Slide 50

Common Inputs to Differential Amplifier Signals can\'t be connected in stage to the contributions of a differential intensifier, since the yields will likewise be in stage, creating zero differential yield. CH 10 Differential Amplifiers

Slide 51

Differential Inputs to Differential Amplifier When the data sources are connected differentially, the yields are 180 ° out of stage; improving each other when detected differentially. CH 10 Differential Amplifiers

Slide 52

Differential Signals A couple of differential signs can be created, among different routes, by a transformer. Differential signs have the property that they have the same normal worth to ground and are equivalent in greatness yet inverse in stage. CH 10 Differential Amplifiers

Slide 53

Single-finished versus Differential Signals CH 10 Differential Amplifiers

Slide 54

Differential Pair With the expansion of a tail current, the circuits above work as a rich, yet powerful differential pair. CH 10 Differential Amplifiers

Slide 55

Common-Mode Response CH 10 Differential Amplifiers

Slide 56

Common-Mode Rejection Due to the altered tail current source, the info normal mode quality can fluctuate without changing the yield regular mode esteem. CH 10 Differential Amplifiers .

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