Top Banner

of 32

Analog_lect_10_07022012

Jun 03, 2018

Download

Documents

Angad Sehdev
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript

  • 8/12/2019 Analog_lect_10_07022012

    1/32

    EEE C364/INSTR C 364

    Analog Electronics

    Lecture 10

    07-02-2012

  • 8/12/2019 Analog_lect_10_07022012

    2/32

    Isolation Device Technology

    Transformer isolation

    Optical Isolation

    Capacitor isolation

  • 8/12/2019 Analog_lect_10_07022012

    3/32

    Isolation Device Technology contd..

    GaASP or AlGaAs

  • 8/12/2019 Analog_lect_10_07022012

    4/32

    Isolation Device Technology contd..

  • 8/12/2019 Analog_lect_10_07022012

    5/32

    Isolation Device Technology contd..

  • 8/12/2019 Analog_lect_10_07022012

    6/32

    Isolation Device Technology contd..

  • 8/12/2019 Analog_lect_10_07022012

    7/32

    Optical isolator or opto isolator or opto coupler or photo coupler or photo MOS

  • 8/12/2019 Analog_lect_10_07022012

    8/32

  • 8/12/2019 Analog_lect_10_07022012

    9/32

    Programmable Gain Amplifier (PGA)

  • 8/12/2019 Analog_lect_10_07022012

    10/32

    Programmable Gain Amplifier (PGA)

  • 8/12/2019 Analog_lect_10_07022012

    11/32

    The Topics covered in this session

    Current Controlled Voltage Source or Voltage shunt feedback amplifier

    Differential voltage-to-current converter

    Constant high current source

    Current Controlled Current Source or Current shunt feedback amplifier

    Voltage Controlled Current Source or Current series feedback amplifier

    Voltage-to-current converter for grounded load

    Inductance Simulation

    Voltage Controlled Voltage Source or Voltage series feedback amplifier

    Negative feedback amplifiers and controlled sources

  • 8/12/2019 Analog_lect_10_07022012

    12/32

    Negative feedback Amplifiers and Controlled Sources

    For an ideal Amplifier, the input drawn from the

    signal source is zero and the output load power

    is finite.

    For the input power to be zero,

    (i) Vi=0 and Ii finite (Zin 0)

    (ii) Ii=0 and Vi finite (Zin )

  • 8/12/2019 Analog_lect_10_07022012

    13/32

    The ideal voltage amplifiers are classified in four different ways:

    1. Voltage Controlled Voltage Source (VCVS) orideal voltage amplifier (Zin , Zout 0, A=Av)

    or Voltage series feedback amplifier

    2. Current Controlled Voltage Source (CCVS) or

    Ideal transresistance amplifier (Zin 0, Zout 0, A=Rm)

    or Voltage shunt feedback amplifier

    3. Voltage Controlled Current Source (VCCS) or

    ideal transconductance amplifier (Zin , Zout , A=Gm)

    or Current series feedback amplifier

    4. Current Controlled Current Source (CCCS) or

    Ideal current amplifier (Zin 0, Zout , A=Ai)

    or Current shunt feedback amplifier

    Negative feedback Amplifiers and Controlled Sources

  • 8/12/2019 Analog_lect_10_07022012

    14/32

    )ABW(1BWfeedbackwithBandwidth(iv)

    )A(1ZZfeedback,currentfor

    1Zfeedback,for

    Zfeedback,withImpedanceOutput(iii)

    1Zfeedback,shuntfor

    )A(1ZZfeedback,seriesfor

    feedbackwithImpedanceInput(ii)

    feedback,withoutgain-A

    1feedbackGain with(i)

    f

    outoutf

    outf

    outf

    inf

    ininf

    inf

    A

    Zvoltage

    A

    Z

    Z

    V

    Vwhere

    A

    AA

    out

    in

    O

    f

    f

    Negative feedback Amplifiers and Controlled Sources

  • 8/12/2019 Analog_lect_10_07022012

    15/32

    Voltage-Controlled Voltage Source

    The Ideal Voltage Amplifier

  • 8/12/2019 Analog_lect_10_07022012

    16/32

    Voltage-Controlled voltage Source- The Ideal Voltage Amplifier

    Example: Non-inverting Amplifier

  • 8/12/2019 Analog_lect_10_07022012

    17/32

    2

    1Oifin

    21

    2fini

    1V

    ,VV0,Vsince

    andVVVHere:GainVoltage(i)

    R

    R

    Vhavewe

    RR

    RVV

    i

    Of

  • 8/12/2019 Analog_lect_10_07022012

    18/32

    Voltage-Controlled voltage Source- The Ideal Voltage Amplifier

  • 8/12/2019 Analog_lect_10_07022012

    19/32

    feedback.withincreasesimpedanceinputThus.V

    )1(

    VfeedbackwithImpedanceInput(ii)

    f

    iinf

    o

    inin

    f

    inout

    i

    in

    in

    i

    in

    in

    i

    i

    Vwhere

    AZZAAZ

    AVV

    ZV

    V

    ZV

    V

    IZ

  • 8/12/2019 Analog_lect_10_07022012

    20/32

    Voltage-Controlled Voltage Source- The Ideal Voltage Amplifier

  • 8/12/2019 Analog_lect_10_07022012

    21/32

    A1

    Z Z),(ansmaller thmuchis

    A1

    Zsince

    )(||A1

    ZZThus

    network.dividerpotentialofeffecttheincludewillimpedanceoutputtotalThe

    RR

    RV

    )1(I,figurethefrom

    Zfeedback,withImpedanceOutput(iii)

    outoutf21

    ou t

    21ou t

    outf

    21

    2fou t

    outf

    RR

    RR

    VVZ

    AV

    Z

    AVV

    I

    V

    ou tout

    ou t

    ou t

    out

    fou t

    ou t

    out

  • 8/12/2019 Analog_lect_10_07022012

    22/32

    Current-Controlled Voltage Source (CCVS)- The Transresistance Amplifier

  • 8/12/2019 Analog_lect_10_07022012

    23/32

    Current-Controlled Voltage Source (CCVS)- The Transresistance

    Amplifier

    RRwith

    A

    RZ

    S

    SoutoutfinfR

    A1

    Z Zand

    1

  • 8/12/2019 Analog_lect_10_07022012

    24/32

    Voltage-Controlled Current Source (VCCS)-

    The Ideal Transconductance Amplifier

    Where Gm - transconductance

  • 8/12/2019 Analog_lect_10_07022012

    25/32

    Voltage-Controlled Current Source (VCCS)-

    The Ideal Transconductance Amplifier

  • 8/12/2019 Analog_lect_10_07022012

    26/32

    Voltage-Controlled Current Source (VCCS)-

    The Ideal Transconductance Amplifier

    Here Ii=0 and Vi = Vf= IOR

    imVGR

    iOV

    ITherefore

    LO RR

    R

    Vand

    f

    V

    )1( AZZ innfi

    ARZisimpedanceoutputThe

    .

    R

    VIequalsandRoftindependeniscurrentoutputThe

    outf

    i

    OL

    This circuit acts as perfect voltage-to-current converter with Zif ,

    Zout and Gm= 1/R.

  • 8/12/2019 Analog_lect_10_07022012

    27/32

    Voltage-to-Current converter for grounded load

  • 8/12/2019 Analog_lect_10_07022012

    28/32

    2

    2

    1

    2ref

    3

    2

    4

    2O

    R

    V-Vand

    R

    V-VhaveweKCL,Applying

    R

    VVR

    VI

    O

    L

    2

    1

    2

    2or R

    R

    VVVV

    ref

    O

    3

    2

    2

    14

    2

    R

    VIR

    RR

    VVL

    ref

    124

    3

    4

    1

    2

    23

    2

    421

    2Voror

    R

    VRIR

    R

    R

    R

    R

    R

    VIRR

    R

    VV ref

    LL

    ref

    Choosing R1R4=R2R3, we have

    341

    2

    R

    V

    RR

    RVI

    ref

    refL

    Voltage-to-Current converter for grounded load

  • 8/12/2019 Analog_lect_10_07022012

    29/32

    Differential voltage-to-current converter

  • 8/12/2019 Analog_lect_10_07022012

    30/32

    Differential voltage-to-current converter

    Writing KCL equations

    R

    VV

    R

    VV OLL 2

    R

    VVIand OLL

    R

    V-V L1

    R

    VVIor LL

    2L1

    R

    V-V

    R

    V-VIHence 21L

    2O 2Vand VVL

    Thus the load current is proportional to (V1-V2)

  • 8/12/2019 Analog_lect_10_07022012

    31/32

    Constant high current source

    LE

    S

    Z IIR

    V

  • 8/12/2019 Analog_lect_10_07022012

    32/32

    Digitally controlled 4-20 mA current source