Session 16 Single-stage amplification circuits...

Session 16

Single-stage amplification

circuits (BJT)

Electronic Components and Circuits

José A. Garcia-Souto / Pablo Acedo

www.uc3m.es/portal/page/portal/dpto_tecnologia_electronica/Personal/JoseAntonioGarcia

Single-stage amplification circuits

Transistor configurations as an

amplification device

OBJECTIVESOBJECTIVES• To review the process of analyzing the characteristic

parameters of amplifiers.

• Analyze small-signal circuits for single-stage BJT amplifiers :

– Common emitter.

– Common-emitter with RE (emitter degeneration).– Common-emitter with RE (emitter degeneration).

– Common-Colector.

– Common-Base.

• Compare the features of these configurations.

2UC3M 2010 ECC - Session 16

Characteristic parameters of amplifiers

Amplifier

Voltage Gain, Av y Gv

Current Gain, Ai i

o

vV

VA =

i

oi

i

iA =

g

ov

V

VG =

Current Gain, Ai

Input resistance, Rin

Output Resistance, Rout

3

iV

i

iin

i

VR =

o

oout

i

VR =

g

UC3M 2010 ECC - Session 16

Input Impedance Analysis

Amplifier

t

tin

i

VR =

Amplifier

4

∞→

=

LRt

ti

i

VR


Output Impedance Analysis

V

Amplifier

0=

=

gVt

tout

i

VR

Amplifier

5

0=

=

iVt

to

i

VR


Single stage amplifiers

• Common-emitter amplifier (CE)

• Common-emitter amplifier with RE and emitter degeneration• Common-emitter amplifier with RE and emitter degeneration

• Common-collector amplifier (CC) or emitter-follower

• Common-base amplifier (CB)

CE

CE-RECC CB


Common-emitter amplifier (CE)

EXAMPLE

βo = 100

VA = 100 V

Ω Rb = 100 kΩ

Rc = 8 kΩ

RL = 100 kΩ

Vcc = Vee = 10V

Iee = 1mA

mAICQ 1≈

7

(1) BIAS ANALYSIS ∞→eoi CCC ,,

(Open Circuit)

eeE II =

eeCQ II ≈

CQ

VmAgm /40=

Ω= kr 5,2π

Ω= kr 1000


Common-emitter (Impedances)

ii oi

(2) SMALL SIGNAL ANALYSIS

rR ≈


πrRR bin //= ππ

rRrRin

b

≈>>

ocout rRR //= cRrout RRco

≈>>

πrRib =

ooc rR =

Common-emitter (Small Signal)

ii oi

(2) SMALL SIGNAL g

iRR

Vi

+= in

g

RVV =π

9

(2) SMALL SIGNAL

ANALYSIS ing

iRR

i+

=ing

gRR

VV+

=π

)////( Lcomo RRrVgV π−=outL

outmo

RR

RVgi

+−= π


Common-emitter (Gain)

ii oi

ino RRRrg

VG −== )////(

)////( Lcomo

v RRrgV

VA −==

π

oβ−≈

cmRrvo RgAco

−≈>>

10

ing

inLcom

g

ov

RRRRrg

VG

+−== )////(

in

outL

outm

i

oi R

RR

Rg

i

iA

+−==

)////( Lco

g

o

rRv RRrrR

Gb

π

βπ +

−≈>>

orRscib

A βπ

−=>>)(


Common-emitter amplifier with RE

11

21 // bbb RRR =

EXAMPLE

…

Re = 1 kΩmAICQ 1≈


ii oi

Common-emitter with RE (Impedace)

V eoe

ib RrrV

VVR )1( βπ

π ++=+

=

12

eme RVgr

VV ⋅

+= π

π

π

ei VVV += π


eoib RrrV

R )1( βπ

ππ

++==

cRrout RRco

≈>>

[ ]eobin RrRR )1(// βπ ++=

ii oi

Common-emitter with RE (Small Signal)

)//( Lcmo RRVgV π−≈g

ing

ingi V

RR

RVV ≈

+=

13

ing

g

iRR

Vi

+=

outL

outmo

RR

RVgi

+−= π

Lcmo π

eme RVgr

VV ⋅

+= π

π

π

ei VVV += π

ing RR +

emi RgV

V

+≈

1

1π


ii oi

Common-emitter with RE (Gain)

( ) eo

Lco

i

ov

Rr

RR

V

VA

·1

)//(

β

β

π ++−==

( )cmco RgR

A −≈−=β

Lc

L

e

c

e

LcRR

RrvRR

R

R

R

R

RRG

ing

eo +⋅−≈−≈

<<

<<

)//(βπ

14

( ) em

cm

eo

covo

RgRrA

+−≈

++−=

11 βπ

o

RRg

RRsci

in

ibb

A β−≈<<

>>)(

b

ibb

cL

co

i

oi

R

RR

RR

R

i

iA

+

+−== β


Common-collector amplifier (CC)

15

21 // bbb RRR =

LeEMITTER RRR //=mAICQ 1≈EXAMPLE

…


Common-collector (Impedances)

ii

LoEM RrR //=

oi


EMoe

ib RrrV

VVR ⋅++=

+= )1( βπ

ππ

π( ) ( )o

gb

o

gb

oout

RRrRRrrR

ββ

ππ

+

+≈

+

+=

1

//

1

////

Common-collector (Small Signal)

ii

LoEM RrR //=

oi

gVi =

g

ing

ingi V

RR

RVV ≈

+=

17

+

+=

Lo

omo

Rr

rVg

r

Vi π

π

π

ing

g

iRR

Vi

+=

ei VVV += π

ing RR +

eo VV =EMme RVgr

VV ⋅

+= π

π

π


ii

Common-collector (Gain)

oi

( )( ) EMo

EMo

i

ov

Rr

R

V

VA

⋅++

⋅+==

β

β

π 1

11≈= o

vV

VG

18

( ) EMoi RrV ⋅++ βπ 1gV

( )b

ibb

Lo

oo

i

oi

R

RR

Rr

r

i

iA

+

++== β1

o

RRg

RRsci

in

ibb

A β+≈<<

>>1)(


Common-base amplifier (CB)

19

EXAMPLE

…

mAICQ 1≈


oi

Common-base (Small Signal)

ii ing

g

iRR

Vi

+=ei VV =

ingi

RVV

+= V

20

outL

outmo

RR

RVgi

+−= π

ing

giRR

VV+

=

πVVe −=

)//( Lcmo RRVgV π−≈

+−= π

π

π Vgr

Vi mi


oi

Common-base (Characteristics)

V+==

ii

mo

ing

rR

1

1≈

+=

βπ

)//( Lcm

i

ov RRg

V

VA +==

cmvo RgA +=

α=A

21

cRrout RRco

≈>>

α=)(sciA


ComparisonStage Rin Rout Av Ai(sc)

CE

ππ rrRb ≈//oc rR // )////( Lcom RRrg−

oinmRg β−≈−

CE-RE

CC

CB

ππb //

r 1

oc rR //

cR

)////( Lcom RRrg−oinmRg β−≈−

[ ]eob RrR )1(// βπ ++ ( ) eo

Lco

Rr

RR

·1

)//(

β

β

π ++− o

b

ibbo

R

RRββ −≈

+−

[ ]EMob RrR ⋅++ )1(// βπ

( )o

gb RRr

β

π

+

+

1

//( )

( )1

1

1≈

⋅++

⋅+

EMo

EMo

Rr

R

β

β

π

( )b

ibbo

R

RR ++ β1

αβ

=

22

T

Aom

máx

CEvV

VrgG −=−≈

CB

mo g

r 1

1≈

+ βπ

ing

invv

RR

RAG

+=

cR ( )α

β

β=

+ o

o

1)//( Lcm RRg+

1≈máx

CCvG


ANNEX 1: Characteristics CE

ii oi πrRib =

ooc rR =

πrRR bin //= ππ

rRrRin

b

≈>>

ocout rRR //= cRrout RRco

≈>>

ino RRRrg

VG −== )////(

)////( Lcomo

v RRrgV

VA −==

π

)//( comvo RrgA −=

cmRrvo RgAco

−≈>>

23

ing

inLcom

g

ov

RR

RRRrg

V

VG

+−== )////(

in

outL

outm

i

oi R

RR

Rg

i

iA

+−==

)////( Lco

g

o

rRv RRrrR

Gb

π

βπ +

−≈>>

)////( Lcom

rR

rRv RRrgGg

b

−≈<<

>>

π

π

inmsci RgA −=)(

orRscib

A βπ

−=>>)(


ii oi

ANNEX 2: Characteristics CE with RE

eoe

ib RrrV

VVR )1( βπ

ππ

π ++=+

=

[ ]eobin RrRR )1(// βπ ++=

cRrout RRco

≈>>

( ) eo

Lco

i

ov

Rr

RR

V

VA

·1

)//(

β

β

π ++−== ( ) em

cm

eo

covo

Rg

Rg

Rr

RA

+−≈

++−=

11 β

β

π

LcLcRR RRRRG

ing ⋅−≈−≈<< )//(

( )inLcoo

v

RRRVG

+⋅

++−==

β

β )//(

24

Lc

L

e

c

e

LcRR

RrvRR

R

R

R

R

RRG

ing

eo +⋅−≈−≈

<<

<<

)//(βπ( ) ingeog

vRRRrV

G+

⋅++

−==βπ 1

o

RRg

RRsci

in

ibb

A β−≈<<

>>)(

b

ibb

cL

c

o

i

o

iR

RR

RR

R

i

iA

+

+−== β

b

ibbosci

R

RRA

+−= β)(


ii

ANNEX 3: Characteristics CC

EMoe

ib RrrV

VVR ⋅++=

+= )1( βπ

ππ

π

[ ]EMobin RrRR ⋅++= )1(// βπ

oi

( ) ( )o

gb

o

gb

oout

RRrRRrrR

ββ

ππ

+

+≈

+

+=

1

//

1

////

( )( )

11

1≈

⋅++

⋅+=

oo

oovo

rr

rA

β

β

π

( )( )

11

1≈

+⋅

⋅++

⋅+== inEMoo

vRR

R

Rr

R

V

VG

β

β ( )b

ibb

Lo

oo

i

oi

R

RR

Rr

r

i

iA

+

++== β1

25

( )( ) EMo

EMo

i

ov

Rr

R

V

VA

⋅++

⋅+==

β

β

π 1

1

( )1

1≈

+⋅

⋅++==

ingEMog

vRRRrV

Gβπ

bLoi RRri +

( )b

ibbosci

R

RRA

++= β1)(

o

RRg

RRsci

in

ibb

A β+≈<<

>>1)(


oi

ANNEX 4: Characteristics CB

mo

ing

rR

1

1≈

+=

βπ

cout RR ≈

ii

cRrout RRco

≈>>

inLcm

ov

RRRg

VG

++== )//(

)//( Lcm

i

ov RRg

V

VA +==

cmvo RgA +=

( )ccoo RRi

A === αβ

26

ing

Lcm

g

vRR

RRgV

G+

+== )//(

gm

Lcm

g

ov

RgRRg

V

VG

+==

1

1)//(

( ) Lc

c

Lc

c

o

o

i

oi

RRRRiA

+=

++== α

β1

α=)(sciA


Session 16 Single-stage amplification circuits...

Documents

Transcript of Session 16 Single-stage amplification circuits...