capitolul 2. surse de curent -...

Capitolul 2. Surse de curent

1. Clasificare

1. Clasificare1. Surse de curent elementare2. Surse de curent cascod3. Surse de curent cu autopolarizare4. Surse de curent cu dependenta redusa cu temperatura

2. Parametrii surselor de curent

2. Parametrii surselor de curent1. Curentul de iesire, IO2. Rezistenta de iesire, RO3. Tensiunea minima de iesire, Vomin4. Coeficientul relativ de variatie cu temperatura, TCR

5. Sensibilitatea curentului de iesire fata de variatiile VDD

6. Precizia de realizare a sursei de curent

dTdI

T1TCR O====

DD

O

O

DD

DDDD

OOVI dV

dII

VV/dVI/dI

S DDO

========

Caracteristica de iesire

3. Surse de curent elementare


Oglinda de curent

VO VDD

T2 T1

R IO

RO

I

(((( )))) (((( )))) O2

T2GS2

T1GS IVV2KVV

2KI ====−−−−====−−−−====

1GSODD VRIV ++++====

(((( ))))2T1GSO VV

2KI −−−−====

(((( )))) 1GS2

T1GSDD VVV2

KRV ++++−−−−====

(((( )))) )VV(KR21KR1

KR1VV TDDT2,11GS −−−−++++±±±±−−−−====

(((( ))))TDDT1GS VVKR21KR1

KR1VV −−−−++++++++−−−−====

Calculul curentului de iesire IO (T1 = T2)


Oglinda de curent

Calculul rezistentei de iesire RO

O2dsO I

1rRλλλλ

========

Calculul tensiunii minime de iesire VOmin

KI2

VVVV OT2GSsat2DSminO ====−−−−========

1GS

O

1DS

2DS

1DS2

T1GS

2DS2

T2GSOV1V1

V1V1

)V1()VV(2K

)V1()VV(2K

II

λλλλλλλλ

λλλλλλλλ

λλλλ

λλλλ

++++++++

====++++++++

====++++−−−−

++++−−−−====

Erorile introduse de efectul de modulare a lungimii canalului

VO VDD

T2 T1

R IO

RO

I

Sursa de curent cu rezistente in sursa

T2T1

R3 R2

R1 IO

VOVDD

I

RO

1GS21DD V)RR(IV ++++++++====

(((( ))))2T1GS VV

2KI −−−−====

T1GS VV >>>>

(((( ))))TDD212121

T1GS VV)RR(K21)RR(K

1)RR(K

1VV −−−−++++++++++++

++++++++

−−−−====

(((( )))) (((( ))))2T2GS

32GS

2T1GS

21GS VV

2KR

VVV2

KRV −−−−++++====−−−−++++

Calculul curentului de iesire IO

(((( ))))2T2GSO VV

2KI −−−−====

Sursa de curent cu rezistente in sursa


(((( ))))32m2dsO Rg1rR ++++====


3OO

3OT2GS3Osat2DSminO RIKI2

RIVVRIVV ++++====++++−−−−====++++====

T2T1

R3 R2

R1 IO

VOVDD

I

RO

4. Surse de curent cascod


VO

IO

VDD

I

T3 T2

T1 T4

RO

A

Sursa de curent cascod (I)

3DS

2DSOV1V1

II

λλλλλλλλ

++++++++

====




(((( )))) 2dsm2ds1m1ds0 rgrg1rR ≅≅≅≅++++====

(((( ))))KI22VVV2VVVVVV TTGSTGSGSsat1DSAminO ++++≅≅≅≅−−−−====−−−−++++====++++====


Sursa de curent cascod (II)




VDD

I

IO

T6

T5

T4

T3

T2

T1

RO

A

VO

IIO ≅≅≅≅

(((( ))))[[[[ ]]]] 3ds

2m1ds2m2ds3m3dsO rgrg1rg1rR ≅≅≅≅++++++++====

TGSsat3DSAminO VV3VVV −−−−====++++====

4. Surse de curent cascodSursa de curent cascod (III)




IIO ≅≅≅≅IO

I

VDD

T6 (K)

T5 (K)

T4 (K/4)

T3 (K)

T2 (K)

T1 (K)

VO

RO

(((( )))) 2dsm1ds2m2dsO rgrg1rR ≅≅≅≅++++====

2GS5GS4GS3GS1DS VVVVV −−−−−−−−++++====

T1GSTTTT1DS VVKI2

KI2V

KI2V

KI8V

KI2VV −−−−========

++++−−−−

++++−−−−

++++++++

++++====

KI22VVV 1DSsat2DSminO ====++++====


Sursa de curent cascod (IV)


R

VDD

T7

T5

T4 T1

T6

T3 T2

I

IO

VO

IIO ====

KI22VVV2VVV TTGS7DSsat6DSminO ++++====−−−−====++++====



Sursa de curent cascod (V)


VDD

I1 = 7I I2 = 4I I3 = I I4 = I I5 = 4I

T2T6

VO

T1

T3T4T8T7

T5

8(W/L) 8(W/L)

7(W/L)7(W/L)

IO

W/L W/L W/L W/L

I7II8IO ====−−−−====

4. Surse de curent cascodSursa de curent cascod (V)


(((( ))))2T3GS VV)L/W(

2'KI4 −−−−====

(((( ))))2T4GS VV)L/W(

2'KI −−−−====

(((( ))))2T2GS VV)L/W(8

2'KI8 −−−−====

(((( ))))2T1GS VV)L/W(7

2'KI7 −−−−====

VDD

I1 = 7I I2 = 4I I3 = I I4 = I I5 = 4I

T2T6

VO

T1

T3T4T8T7

T5

8(W/L) 8(W/L)

7(W/L)7(W/L)

IO

W/L W/L W/L W/L

4. Surse de curent cascodSursa de curent cascod (V)


T2GST4GS VVVV −−−−====−−−−

(((( ))))T2GST3GS VV2VV −−−−====−−−−

T2GST1GS VVVV −−−−====−−−−

(((( )))) (((( )))) sat2DST2GST4GST3GS4GS3GS2DS VVVVVVVVVV ====−−−−====−−−−−−−−−−−−====−−−−====

(((( )))))L/W('K

I22VV2VVV T2GS2DSsat1DSminO ====−−−−====++++====

VDD

I1 = 7I I2 = 4I I3 = I I4 = I I5 = 4I

T2T6

VO

T1

T3T4T8T7

T5

8(W/L) 8(W/L)

7(W/L)7(W/L)

IO

W/L W/L W/L W/L

5. Surse de curent cu autopolarizare


Sursa de curent cu autopolarizare (I)

IO

VDD

R1

T6T5

T4T3

T2T1

−−−−====

th

TGS0DD nV

VVexp

LWII

====

−−−−−−−−++++====

54

63

1

th

1

6GS3GS5GS4GSO )L/W()L/W(

)L/W()L/W(ln

RnV

RVVVV

I


Sursa de curent cu autopolarizare (II)

IO

VDD

T6T5

T4T3

T2 T1

4K K

A10A

(((( ))))[[[[ ]]]]2thO 10lnV)L/W('K2I ====

++++++++====

++++++++

S

Oth

OT

S

Oth

OT I10

IlnV

)L/W('KI2

VII

lnV)L/W('K4

I2V


Sursa de curent cu autopolarizare (III) VDD

R2

R1 T1

T3 T2

T6T5 T4

IO I IO

B A

1

1EBO R

VI ====

DD

O

O

DDVI dV

dII

VS DD

O====

++++++++++++

====

++++++++====

========

5SD

4SD

1

th

S

O

1

th

5SD

4SD

S

O

1

th

S1

th

1

1EBO V1

V1lnRV

IIln

RV

V1V1

IIln

RV

IIln

RV

RVI

λλλλλλλλ

λλλλλλλλ

1

th

DD

0

O1

th

DD

ORV

dVdI

IRV

dVdI λλλλ

++++====

DDBE

th

thBE

DDVI V

VV

1V

VVS DD

Oλλλλλλλλ ≅≅≅≅

−−−−≅≅≅≅

1EB2GSDD4SD VVVV −−−−−−−−====

5SG5SD VV ====

Dependenta IO (T)


Dependenta IO (VDD)



Sursa de curent cu autopolarizare (IV)

VDD

R2

R1 T1

T3 T2

T8T5 T4

T9T6 T7

I0 I

1

1EBO R

VI ====

++++++++====

6SG6

6SG7

S

O

1

thO V1

V1IIln

RVI

λλλλλλλλ

(((( ))))DD

6SG67

BE

DDthVI dV

dVV

VVS DD

Oλλλλλλλλ −−−−====

Dependenta IO (VDD)



Sursa de curent cu autopolarizare (V)

VO

IO

R

T5 T2 T1

VDD

T4 T3

[[[[ ]]]])V2V(1lnR

nV)L/W()L/W(

lnR

nVI GSDD

th

1

2thO −−−−++++++++

≅≅≅≅ λλλλ

)V2V(R

nV)L/W()L/W(

lnR

nVI GSDD

th

1

2thO −−−−++++

≅≅≅≅ λλλλ

≅≅≅≅

1

2

DDVI

)L/W()L/W(

ln

VS DD

O

λλλλ

1)V2V( GSDD <<<<<<<<−−−−λλλλ

6. Surse de curent cu dependenta redusa cu temperatura


6.1. Surse de curent PTAT (I) (Proportional To Absolute Temperature)

IO

R

T5

T2 T1

VCC

T4 T3 1:1

====

====−−−−====

4C

3Cth

1S

2S

2C

1Cth2BE1BEO I

InlnR

VII

IIln

RV

RVVI

A

CC

A

4EBA

1BECC

4S

3S

4C

3CV

V1

VV1

VVV1

II

II ++++≅≅≅≅

++++

−−−−++++====

++++++++====A

CCththO V

V1lnR

VnlnR

VI

(((( ))))nln1

VV

dVdI

IVS

A

CC

CC

O

O

CCVI

CCO

≅≅≅≅====4S3S

1S2SII

nI/I====

====


6.1. Surse de curent PTAT (II)

VDD

R

T7 T1

T3 T2

T6T5 T4

IO

W/L n(W/L)

B A W/L n(W/L)

++++−−−−

++++====−−−−====−−−−

2

2DT

3

3DT2GS3GSBA K

I2VKI2VVVVV

−−−−====−−−−

2

3

3D

2D

3

3DBA )L/W(

)L/W(II1

KI2VV

545D4D3D2D )L/W/()L/W(I/II/I ========

−−−−====−−−−

2

3

5

4

3

3DBA )L/W(

)L/W()L/W()L/W(1

KI2VV

(((( )))) (((( )))) (((( )))) (((( ))))4352BA L/WL/WL/WL/WVV ====⇒⇒⇒⇒====

====

====

−−−−====

1S

7Sth

1S

7S

7C

1Cth7BE1BEO I

InlnR

VII

IIln

RV

RVV

I


6.1. Surse de curent PTAT (II)

Dependenta IO (T)


6.2. Surse de curent CTAT (I) (Complementary To Absolute Temperature)

T2

T1

R2

R1 IO

VCC

S1

2BE1BECC

2

th

2

1BEO IR

VVVlnRV

RVI −−−−−−−−≅≅≅≅====

04.0VV

dVdI

IVS

BE

th

CC

O

O

CCVI

CCO

≅≅≅≅≅≅≅≅====


6.2. Surse de curent CTAT (II) (Complementary To Absolute Temperature)

VCC

R1

T4

T3

T2 T1

IO I

1

BEO R

VI 3====

++++====

====

A

CC

S

O

1

th

S

1C

1

thO V

V1IIln

RV

IIln

RVI

CC

ABE

th

CC

O

O

CCVI

VV1

1VV

dVdI

IVS CC

O ++++========


6.2. Surse de curent CTAT (II) (Complementary To Absolute Temperature)

Dependenta IO (T)

6. Surse de curent cu dependenta redusa cu temperatura6.3. Sursa de curent cu corectie liniara a caracteristicii

+ -

R1R2

R3

VD

T3

T6T5

T9

VO

A

T8T7T1

T2

T4

IO

W/Ln(W/L)

W/Ln(W/L)

W/L

NM

3GS3D

T2D

T2GS V)L/W('K

I2V

)L/W(n'KI2

VV ====++++====++++====

(((( ))))nlnVRRV

RVVRV th

1

2PTAT

1

7BE1BE2R2 ========−−−−====⇒⇒⇒⇒

(((( ))))

++++==== )T(VnlnVRR

R1)T(I 8BEth

12

3O

nI/I 7S1S ====

(((( ))))

++++==== )T(VnlnV

RR

RI)T(I 8BEth

1

2

3O

(((( )))) 0nlnqk

RR

TE)T(VTinliniartermenanulare

1

2

0

0G0BE ====++++−−−−⇒⇒⇒⇒

(((( ))))

−−−−++++−−−−++++====

00

0G0BE0GBE T

Tlnq

kT1TT

E)T(VE)T(V ηηηη

−−−−++++====⇒⇒⇒⇒

00G

3O T

Tlnq

kT)1(ER1)T(I ηηηη


+

-

R1R2

R3

VD

T3

T6T5

T9

VO

A

T8T7T1

T2

T4

IO

W/Ln(W/L)

W/Ln(W/L)

W/L

NM

Dependenta IO (T)


Dependente VM -VN (T)


(W/L)2(W/L)5 = (W/L)3(W/L)4 (W/L)2(W/L)5 ≠≠≠≠ (W/L)3(W/L)4

6. Surse de curent cu dependenta redusa cu temperatura6.4. Surse de curent PTAT2 (I)

VDD

IOUT’

IIN

IO IO

IIN/2

IOUT

(((( )))) (((( )))) (((( ))))INOUTGSOUTGSOGS I'IV'IVIV2 −−−−++++====

INOUTOUTO I'I'II2 −−−−++++====

O

2ININ

OOUT I16I

2II'I ++++++++====

O

2ININ

OOUTOUT I16I

2II'II ====−−−−−−−−====

2OUTIN T.ctIT.ctI ====⇒⇒⇒⇒====

6. Surse de curent cu dependenta redusa cu temperatura6.4. Surse de curent PTAT2 (II)

IO

IO

IIN

IOUT’IOUT’ 2IO IO

V3 V2V1

IO

IOUT’I3

VDD

K K K K

K 2K K K K

K K 4K K

IO

T5

T4

T6

T3 T2T1

IIN/2

IOUT

IO/4

++++++++====

K'I2

KI2

21VV OUTO

T3

(((( )))) 'II2'IIVVK2I OUTOOUTO2

T33 ++++++++====−−−−====

INOUTO3 I'II2I ++++++++====

O

2ININO

2

O

INOOUT I4

I2

I4

III1

4I'I ++++++++====

++++====

O

2ININO

OUTOUT I4I

2I

4I'II ====−−−−−−−−====

2OUTIN T.ctIT.ctI ====⇒⇒⇒⇒====

6. Surse de curent cu dependenta redusa cu temperatura6.5. Surse de curent PTATn

IOUT

IO IIN

SQ

IO IIN

IOUT(1)

O

2IN

)1(OUT III ====

IOUT

IO IIN

SQ

IIN IOUT(1)

IOUT(2)

2O

3IN

IN

2)1(OUT

)2(OUTII

II

I ========

IOUT

IO IIN

SQ

IOUT(n-3) IOUT(n-2)

IOUT(n-1)

1nO

nIN

)3n(OUT

2)2n(OUT

)1n(OUTII

II

I −−−−−−−−

−−−−−−−− ========

capitolul 2. surse de curent -...

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