slide chuong5.machphancuctransistor

7/31/2019 Slide Chuong5.Machphancuctransistor

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MCH PHN CC

CA TRANSISTOR

TRNG H PHM VN NG KHOA K THUT CNG NGH

Chng 5


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5.1. Gii thiu

Vicphn tch haythit k mt mch khuch i i hi s hiu bit v p ngdc v acca h thng. Ngita thng nhm ln rng transistor l mt linh kin khuch i tn hium khng cn ngun nng lngcung cp. Thcra vic khuch itn hiuac ltqu trnhchuyn i nng lng t nguncungcpdc. Do vicphn tch hay

thit k bt k 1 mch khuch i in t u cha ng2 phn: phndcv phnac.

Cc mc hot ngdc ca1 transistorc iu khin bi1 s cc thngsbaogm1 dy ccimlmvicc thc trn ccng ctnh catransistor. Cc dngindc v ccmc inp dc phi cxc nh, mt mch in phi cxy dngm ns thit lp imlmvicmongmun cc mch inny s cphn tch trongchngny.


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5.1. Gii thiu

Hnh 5.1. c tuyn ng ra ca BJT

Mt h sphn cckhcrtquan trng cnch n: s la chn v phn cc chotransistorti imlmvicmongmun phitnh n nh hng

ca nhit . Nhit lm thayi cc h s nh ac v dnginICEO . Nhit cngtngthdnginICEO tng lm thayi imlmvicQ.

Do cc mch in phi thit kc s n nh nhit khic sthayi nhit th sthayi ca imlmvicl nh nht. S n nh ca imlm vic c ch nh bi h s n nh S xc

nh mc thay i imlm vic ph thuc vo s thay i ca nhit .


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5.1. Gii thiu

i viBJT vicphn cc hot ngtrong vngtuyntnhcn phich :

1. Mi niB-E phiphn cc thun vi inp phn ccvokhong0,6 n0,7V.

2. Mi ni B-C phi phn cc ngc vi in p phn cc nmtrong gii hn cc i catransistor.


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5.2. PH N TCH NG TI5.2.1. imlm vic tnh v ng ti1 chiu Xt 1tng khuch i n gin nhhnh 5.2.

Hnh 5.2. Tng khuch i n gin .

BJT lmvic ch khuch itnhiukhi:- Tipgip J E phn cc thun.- Tipgip J C phn cc ngc.


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* Xc nh imlm vic tnh Q bng th

- T , ta c:

Hnh 5.3. imQ ng vo.

- pdng nh lutKirchhoff 2 cho ng vo, ta c:

BEBBCCVRIV

B

CCBE

B

B R

VV

R

1I

a. Xc nh imQ ng vo:

gi l ng ti1 chiung voca mch.

ng ti1 chiung voct c tuynng voti1 im, gil imlmvic tnh ng voca mchQ(VBEQ, IBQ)

5.2. PH N TCH NG TI


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- T , ta c:

Hnh 5.4. imQ ng ra.

- pdng nh lutKirchhoff 2 cho ng ra, ta c:

CECCCC VRIV

C

CCCE

C

C R

VV

R

1I

b. Xc nh imQ ng ra:

ng ti1 chiung ract c tuynng rati1 im, gi l imlmvic tnh ng raca mchQ(VCEQ, ICQ)

5.2. PH N TCH NG TI

gil ng ti1 chiung raca

mch.


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Hnh 5.6. imQ thay i theo RC .

Nudng inIB thay i bicc gitr khc nhaucaRB thim tnh Q sdi chuynln hocdi chuyn xung nhhnh 5.5. Nu inp VCC v IB gi c nh v in tr RC thay ith ng ti s dch chuyn nhhnh 5.6.

5.2. PH N TCH NG TI

Hnh 5.5. imQ thay i theo dng I B .


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NuRC c nh v VCC thay ith ng ti dch chuyn nh hnh 5.7.

5.2. PH N TCH NG TI

Hnh 5.7. imQ thay i theo inp V CC

.


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5.2. PH N TCH NG TI5.2.2. ng tixoay chiu Ta c phngtrnh ng rach vitnhiuac:

iC: Dngin ccCollectori vi ctn hiuxoaychiuv tnhiu1 chiu.

0v)R // R(i ceLCc

ce

LC

c v)R // R(

1i

Trong: CQcC I ii CQCc Iii

CEQceCE V vv CEQCEce Vvv

ic: Dngin ccCollectori vitnhiuxoaychiu. ICQ: Dngin ccCollectori vitnhiu1 chiu.


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5.2. PH N TCH NG TI

Vy phngng ra khi cnguntnhiuac l:

Phngtrnh trn chnh l phngtrnhng tiac ca mch.

)Vv()R // R(

1)Ii( CEQCE

LC

CQC

CQ

LC

CEQCE

LC

C I

)R // R(

Vv

)R // R(

1i

0v CE CQLC

CEQ

C I)R // R(

ViKhi th

Khi th0i C CEQLCCQCE V)R // R(Iv


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5.2. PH N TCH NG TI

Nhnxt: ACLL v DCLL lun lun giao nhauti imlmvic tnhQ.

Hnh 5.8. ng ti ACLL , DCLL v dng sng tn hiuvo ra .


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5.3. C C MCH PHN CC CHO BJT5.3.1. Mch khuch iphn cc c nh.Mch k phncc c nh nhhnh 5.9s dngtransistor npn.

Hnh 5.9. Mchphn cc c nh .

S mchhnh 5.9 cthchianguncungcpdc Vcc thnh 2ngun nhhnh 5.10.

Hnh 5.10. Tch nguncung cp .


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5.3. C C MCH PHN CC CHO BJT5.3.1. Mch khuch iphn cc c nh.

Xt mchvng BE:

Hnh 5.11. S nhnh BE.

- pdng nh lutKirchhoff:

Xtmchvng phncc mi niB-Ecahnh 5.11

BE B BCC V R I V

- Suy ra dnginIB:

B

BECCB R

VVI

- T ta cgitrdnginIC:

BC II


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5.3. C C MCH PHN CC CHO BJT5.3.1. Mch khuch iphn cc c nh.

Xt mchvng CE:

Hnh 5.12. S nhnh BE.

- pdng nh lutKirchhoff 2:

Mchvng phncc mi niC-Ec v li nhhnh 5.12.

- Suy rainp VCE:

- Vy to imlmvic tnhQ ca mchl Q(VCE, ICQ).

C C CE CC R I V V

E C CE V V V


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5.3. C C MCH PHN CC CHO BJTV d5.1: Cho s mch nh hnh v5.13.

Hnh 5.13.

BitBJTloiSilic, = 80, RB = 300k, RC = 2k v VCC = 18V.

a. Xcnh imlmvic tnh Q ca mch.

b. V th.c. Xc nh inp trn cc

chncaBJT.


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5.3. C C MCH PHN CC CHO BJTV d5.2: Cho s mch nh hnh v5.104

Hnh 5.14.

BitBJTloiSilic, = 100, RB = 530k, RC = 3k v VCC = 6V.


b. V th.c. Xc nh inp trn cc

chncaBJT.


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Hnh 5.15.

BitBJTloiSilic, = 80, IB =40A, RC = 2,5k v VCC = 20V.

a. Xcnhgitr in tr RB.

b. Tnh dnginIC.c. Tnh VCE.


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* Hot ng bo ha caBJTi vitransistorhot ng vng boha th dngin tgi

tr cc itrongmch in .Cc trng hp boha thngnn trnh bi v mi ni CB

khng cn phncc ngc dn ntnhiung ra bmodng.Trong vng bo ha th ccngcongctnhc ni li vi

nhau vinp CEnm ti mc hoc thp hn mc inp VCEsat. DnginIC c gitr tng i lntrnngcongctnh.

Hnh 5.16. imlm vic vng boha.


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* Hot ng bo ha caBJTTa dng ccngcong xp x nh hnh 5.16b xc nh

nhanh ccmcgi tr trong vng bo ha, th dnginIC tng i ln cninp VCE xemnh bng0V. pdng nh lutOhmtnhin tr mi niCE:

i vi mchphn cc c nh khi transistor ch bo ha ths mch nhhnh5.17, inp ri trn R chnh bngVcc v dnginIC boha c gitr:

Hnh 5.17. Xc nh I Csat vng bo ha.

00

Csat C

CE CE I

V

I

V R

C

CC

Csat R

V I


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5.3. C C MCH PHN CC CHO BJT5.3.2. Mchphn cc c nh n nh ccemitter Mchphnccdc hnh 5.18 c thm 1in tr ti ccEmitter

ci thin mc n nh ca cuhnhmchphncc c nh.

Hnh 5.18. Mch phn cc BJT c thm in tr ccE.

Hnh 5.19. Nhnh BE. Hnh 5.20. Nhnh CE.


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5.3. C C MCH PHN CC CHO BJT- Xt mchvng BE:

Hnh 5.18 cth v li nh hnh 5.19, pdng nh lut Kirchhoff 2, tac phngtrnh:

E E BE B BCC R I V R I V

B E I I )1( M ta c:

Thvo phngtrnh trn, tac:

E B BE B BCC R I V R I V )1(

Rtgnv suy ra dnginIB: E B

BE CC B R R

V V I

)1(

ychnh l gitrdnginIBQ, t suy ra dnginICQ:

BQCQ II

Hnh 5.19.


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5.3. C C MCH PHN CC CHO BJT- Xt mchvng CE:


M ta c:

inp VCE:

C C CE E E CC R I V R I V

EEC III

)( E C C CC CE R R I V V

Thay IC = ICQ vo biu thctrn tac inp VCEQ l:

)RR(IVV ECCQCCCE

Vyta xcnh c ta imlmvic tnhQ(VCE , IC ).

Hnh 5.19.


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Hnh 5.21.

BitBJTloiSilic, = 80, RB = 300k, RC = 2k, RE = 300 vVCC = 18V.


b. Xc nh inp trn ccchncaBJT.


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Hnh 5.22.

BitBJTloiSilic, = 120, RB = 470k, RC = 2,2k, RE = 0,56k vVCC = 20V.




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5.3. C C MCH PHN CC CHO BJT5.3.3. Mchphn cc bng inp hi tip t collector

Xt mchphncc hi tip inp nhhnh 5.23.

Hnh 5.23. Mch khuch i hi tip t ccC. Hnh 5.24. Mch tng ng .


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5.3. C C MCH PHN CC CHO BJT- Xt mchvng BE:


Rtgnv suy ra dnginIB:

)RR)(1(R

VVI

ECB

BECCB


BQCQ II

E E BE B BC C CC R I V R I R I V '

EBBEBBCBCC RI)1(VRIRI)1(V

Hnh 5.24.


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5.3. C C MCH PHN CC CHO BJT- Xt mchvng CE:


inp VCE:

CCBCEEECC R)II(VRIV

)RR)(II(VV ECCBCCCE

Thay IC = ICQ vo biu thctrn tac inp VCEQ l:

Vyta xcnh c ta imlmvic tnhQ(VCE , IC ).)RR(I)1(VV ECBQCCCE

)RR(I)1(VVECBCCCE

Hnh 5.25. Mchvng CE.


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5.3. C C MCH PHN CC CHO BJT

Hnh 5.26

BitBJTloiSilic, = 80, RB = 240k, RC = 3k, RE = 1k v VCC = 9V.



V d5.6. Cho mch in nh hnh 5.26.


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Hnh 5.27.

BitBJTloiSilic, = 90, RB = 250k, RC = 4,7k, RE = 1,2k vVCC = 10V.





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5.3. C C MCH PHN CC CHO BJT5.3.3. Mchphn cc bng cuphn p:

Xt mchphncc bng cuphn pnhhnh 5.28.

Hnh 5.28. Mchphn cc kiuphn p. Hnh 5.29. Mch tng ng

Thvnin.


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21

2121Th

RR

R.RR // RR

Hnh 5.30. Xc nh RTh .

- Xc nh in tr Thevenin RTh bngcch ngn mch ngun inp nh hnh 5.30.

- Xc nh inp Thevenin ETh nh mch in nhhnh 5.31.

Hnh 5.31. Xc nh V Th .

21

22 R R

RV V E CC RTh


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Mch ng tngTheveninnhhnh 5.29 dnginIB c th xcnh bng nh lutKirchhoff:

0E E BE Th BTh R I V R I E

Thaythdng IE = ( + 1) IB vo

suy ra dng IB: E Th

BE Th B R R

V E I

)1(

Phngtrnhmchvng CE khng c g thayi kt qu c:


BQCQ II

)( E C C CC CE R R I V V

Thay IC = ICQ vo biu thctrn tac inp VCEQ.


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Hnh 5.32.

BitBJT loiSilic, = 80, R1 =48k, R2 = 12k, RC = 1,5k, RE = 500 v VCC = 18V.

a. Xcnh imlm vic tnh Qca mch.

b. Xcnh inp trn cc chncaBJT.


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Hnh 5.33.

BitBJT loiSilic, = 125, R1 =40k, R2 = 4k, RC = 20k, RE = 2k vVCC = 22V.

a. Xcnh imlm vic tnh Qca mch.

b. Xcnh inp trn cc chncaBJT.


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5.4. H S N NH NHIT Cc yu tgy bt n nh imlm vic l: inp ngun

cungcp, nhit . yta chxtn yu t nhit v n lin quann vn phncccho transistor.

Khi nhit thay i s nh hng n cc thngs ca transistor,th hin bicc thamssau:

- Dngr:*

12

2)()( 12 T T T

COCO T I T I

Trong T* l binthin nhit lm dnginbo hangc tng gp i thng bng100C.

- H s truyn tdngin , : )75

1( 1212

T T T T

- inp VBE ng viIB = const: C mV V o BE / )5,22(


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5.4. H S N NH NHIT Vykhinhit lmvic catransistor b thayilm cc thng

s trn catransistor thayi theo kt qul imlm vicQ b dch chuyntrnc tuynng ra hnh 5.34.

Tiu chun nhgi s bt n nh ca mchtheonhit l S,cch s n nhl:

CO

C

CO I

I I S )(

BE

C

BE V

I V S )(

C

I S )(

Ta thyS cngnhth n nh nhit ca mchcng cao.

Trongtrng hpl tng, ICO 0 nhng IC =0. Lc ny, S =0. Thc tkhngtn ti trng hpny.


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5.4. H S N NH NHIT Thngthng nh hng caICO ndng IC l nhiu nhtnn

khi nin nh hng ca nhit n imcng tctnh, ngita ch quan tmn nh hng caICO.

CO

C

CO I

I I S )(

Trong: COBC I)1(II )1(I.I

I BCCO

xc nh h s n nh nhitS i vi1 transistor chotrc,

gi skhi nhit thay i, dng ICO thay i1 lng ICO, dng IC thayi 1 lngIC.

)I

I1(

)1(

)I

I1(I

I)1(

1

III

I

I)I(S

C

B

C

B

C

C

BC

C

CO

CCO


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5.4. H S N NH NHIT

Hnh 5.34. S mchphn cc bng dng c nh .

V d5.10. Xt s n nh nhittrong mchsau.

)II

1(

)1(

I

I)I(S

C

BCO

CCO

Ta thy IB = 0 (dng IB lunc nh), nn h s n nh camchl:

)1()I(S CO

H s khuch i ca mch trongtrng hpny ph thucvoh s khuch idngin tnh .

Ngh a l munthay i n nh camch ch cn cch thayitranstor, tuy nhin hs catransistor thngrtln.


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5.4. H S N NH NHIT V d5.11. Xt s n nh nhittrong mchsau.

Hnh 5.35. S mch khuch i n nh ccE.


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5.4. H S N NH NHIT

Ta c: E E BE B BCC R I V R I V

CO E C I I I M:

COCE

III

CCOC

CEB III

III

Thay IB, IE vo biu thcVCC, tac:

BE

CO

BE

EB

C

ECOC

BEBCCOC

CC

RR

I

VRR1

I

RII

VRIII

V


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5.4. H S N NH NHIT

Thay

Tac:1

CO E B

B E

E B

BE CC C I R R

R R

R R

V V I

)1()1(

)1(

)(

- n nh nhittnh theo ICO:

E B

B E CO R R

R R I S

)1()1()(

E

B

E

B

CO

R

R)1(

R

R1

)1()I(S

5 4 H S N NH NHIT


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5.4. H S N NH NHIT

Nu )1( E

B

R

R th )1()( CO I S

Nu th

Nu th

)1(1 E

B

R R

E

BCO

R

R I S )(

1 E

B

R

R1)( CO I S

- n nh nhittnh theo VBE:

E B BE R R

V S)1(

1)(

- n nh nhittnh theo:

)1(

)1()(

21

1

E B

E

BC

R R R

R I S

5 4 H S N NH NHIT


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5.4. H S N NH NHIT

Tcngthctnh n nh nhittrn, tathycc h s bt n nh nhitny c gitr bin ln nhtkhi RE c gitr nhv RB cgitrcngln. VyRE ngvai trn nh nhitchomch.

Tmli s thayi cadng IC theo cc thngs catransistorkhinhit thayil:

)(SV)V(SI)I(SI BEBECOCOC

5 4 H S N NH NHIT


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Hnh 5.36. Mchphn cc bng inp hi tip .

5 4 H S N NH NHIT


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- Xt mchvng BE:

C

ECB

EC

ECB

BECCB IRRR

RR

RRR

VVI

Lyvi phn biu thcIB theo IC, tac:

ECB

EC

C

B

RRRRR

dIdI

E E BE B BC C CC R I V R I R I V '

EBBEBBCBCC RI)1(VRIRI)1(V

)RR(I)RRR(IVV ECCECBBBECC

5.4. H S N NH NHIT

5 4 H S N NH NHIT


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T ta tnh n nh nhitS ca mch:

Khimchkhng c RE th:

)RR)(1(R )RRR)(1(

)RRR

RR1(

)1(

)II

1(

)1(

I

I)I(S

ECB

ECB

ECB

EC

C

BCO

CCO

CB

CBCO R)1(R

)RR)(1()I(S

- NuRB 1. S cngnhth n nh cng cao.Tuy nhin n nhtrongmchny khngth nh hn1 c.

5.4. H S N NH NHIT

5 4 H S N NH NHIT


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Hnh 5.37. Mchphn cc kiuphn p. Hnh 5.38. Mch tng ng Thvnin.


Ta c: 0RIVRIE EEBEThBTh

0R)II(RIVE ECBThBBETh

5 4 H S N NH NHIT


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EB

EC

EB

BETh

B RRR.I

RRVE

I

5.4. H S N NH NHIT

Lyvi phn biu thcIB theo IC, tac:EB

E

C

B

RRR

dIdI

T ta tnh n nh nhitS ca mch:

EB

E

C

BCO

CCO

RR

R1

)1(

)

I

I1(

)1(

I

I)I(S

Khi RE cng b, RB cnglnth S cnggngitr1.

Ta thyS xp x 1 v lunnh hn1. Hn na, h sS khng ph thucvo R

C nghal khng ph thucvoimlmvic tnhS ca

mch.

C MCH PHN CC CHO FET


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5.5. C C MCH PHN CC CHO FET i vitransistortrngth miquanh giang vo v ng r

khng tuyntnh ph thucvo cc thnh phntrong phngtrnhShockley.

MiquanhkhngtuyntnhgiaID v VGS c th phc tp nu dng phngphp tonhc phn tchcuhnh mchdc caFET.

Phngphp th gipkhost nhanh ccmch khuch idng FETnhng b gii hn vsai s.

Mt s khc nhau rrt gia phn tch transistor BJT vtransistor FET li tng iu khin i vi transistor BJT l dnincni vitransistor FET linp.

Tuy nhin trongc2 trng hptn hiura l dnginv s xcnh inp ra.

C MCH PHN CC CHO FET


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5.5. C C MCH PHN CC CHO FET Miquanh tngqut cth cp dng phn tch dc cho

tt cccmch khuch idng FET:

- i vi JFET v MOSFET knh csn th phngtrnhShockley 1 cp dng din t miquanh giacci lngvora:

- i viMOSFET knhcm ngth phngtrnh Shockley 2cp dng:

0G I

S DI I

2

1

P

GS

DSS D V

V I I

2T GS D V V k I

5 5 1 JFET


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5.5.1. JFET

a. Mchphn cc c nh

inp trnin tr RG bng0V nn cth b in tr RG rakhi mch, mch incn li nhhnh 5.40.Kt qu inp ti2 cc GSnhsau:

Hnh 5.39. Mchphn cc c nh . Hnh 5.40. Mchphn tch dc.

GGGS V V

5 5 1 JFET


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5.5.1. JFET

Do VGG l inp cungcp c nhnninp VGS cngc gi

tr c nhnnmch c gil mchphncc c nh.

Hnh 5.41. th phng trnh Shockley Hnh 5.42. Xc nh imQ.

DnginID cxcnh bi phngtrnh:2

1

P

GS DSS D V

V I I

Phn tch bng th i hi phi v th ca phngtrnh

Shockleyctrnh bynhhnh 5.41.

5 5 1 JFET


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5.5.1. JFET

Trong hnh 5.42 tav ng thng ti imc gitr inp VGS

= -VGG , ng thngny ct th ca phngtrnh Shockleyti1im imny cnc gil imlm vicQ. im tnh Q cta VGS v ID.

inp VDS c th cxcnh: D D DD DS R I V V

Bit JFET knh N c: IDSS =10mA, VP = - 8V, RD = 2k, RG =1M v VDD = 16V, VGG = 2V.


b. Xc nh inp trn ccchncaJFET.


Hnh 5.43.

5 5 1 JFET


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5.5.1. JFET

b. Mch t phn cc

- Theonh lutK2 cho ng vo, tac: Hnh 5.44. Mch t phn cc . Hnh 5.45. Mchphn tch dc.

0RIV SDGS

S

GS

D R

VI

5 5 1 JFET


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5.5.1. JFET

Mckhc, ta c:2

P

GSDSSD V

V1II

Gii phngtrnh honhgiaoim,ta c2 nghimVGS.

ChnVGS tha iu kin: |VGS| |VP|.TVGS, ta tnhcID. Sau tnhcVDS theonh lutK2

cho ng ra:

T ta c to ca imlmvic tnhQ (VDSQ, IDQ).)( DS D DD DS R R I V V

5 5 1 JFET


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5.5.1. JFET

Bit JFET knh N c: IDSS =8mA, VP = - 6V, RD = 3,3k, RS =1k, RG = 1M v VDD = 16V, VGG =2V.


c. Xc nh inp trn ccchncaJFET.


Hnh 5.46. Mch t phn cc .

b. V c tuyn.

5 5 1 JFET


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5.5.1. JFET

Bit JFET knh N c: IDSS =10mA, VP = - 3V, RD = 2,7k, RS =452, RG = 1M v VDD = 15V, VGG = 2V.





b. V c tuyn.

5 5 1 JFET


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5.5.1. JFET

c. Mchphn cc bng cuphn p

Hnh 5.48. Mch t phn cc . Hnh 5.49. Mch t phn cc .

21

DD2

Th RR

VRV

21

21

Th RR

R.RR

5 5 1 JFET


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5.5.1. JFET

S

GSThD R

VVI

ThThGSDGS VR.IRIV

2

P

GS

DSSD V

V1II

Gii phngtrnh honhgiaoim,ta c2 nghimVGS.

ChnVGS tha iu kin: |VGS| |VP|.

TVGS, ta tnhcID. Sau tnhcVDS theonh lutK2cho ng ra:

T ta c to ca imlmvic tnhQ (VDSQ, IDQ).

)( DS D DD DS R R I V V

5 5 1 JFET


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5.5.1. JFET

Bit JFET knh N c: IDSS =8mA, VP = - 4V, R1 =2M, R2 =270k, RD = 2,4k, RS = 1,5k, RG =1M v VDD = 16V.





b. V c tuyn.

5 5 2 MOSFET KNH C SN


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5.5.2. MOSFET KNH C SN S gingnhaugiaccngcongcaJFET v MOSFET kn

c sncho php phn tch phnccdc gingnhau.S khc nhauc bn gia JFET v MOSFET knh csnl

MOSFET knh csncho php ccim hot ng vicc gitr dng caVGS v ID ln hngitr IDSS.

Trongthc t i vi tt ccccuhnh khost thvicphntch JFET cththayth bngMOSEFET knh csn.

5 5 3 MOSFET KNH CMNG


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5.5.3. MOSFET KNH CM NG Cc ctnh caMOSFET knhcm ng (knh chac sn)

hon ton khcviJFET v MOSFET knh csn, l dngin cc mng ID caMOSFET knhchac sn bng0 khiinp VGS nh hn inp ngngVT.

Khi inp VGS ln hnVT th dng in cc mng xcnh theo phngtrnh:

2TGSD VVk I

2T)ON(GS)ON(D

VVI

k

Hnh 5.51. c tuyn truyn t ca MOSFET knh cm ng .



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5.5.3. MOSFET KNH CM NG a. Mchphn cc hi tip

Hnh 5.53. Mchrt gn . Hnh 5.52. Mchc hi tip ccG

Do dng IG = 0 mA nn VRG = 0V khi mch inhnh 5.52

tng ng nhhnh 5.53.



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D

DD

D

GSD R

V

R

VI

DDDGS VRIV

Gii phngtrnh honhgiaoim,ta c2 nghimVGS.ChnVGS tha iu kin: |VGS| |VT|.

TVGS, ta tnhcID. Sau tnhcVDS= VGSv IG = 0 nncoinh ngn mch ccD v G.

T ta c to ca imlmvic tnhQ (VDSQ, IDQ).

5.5.3. MOSFET KNH CM NG Theonh lutK2 cho ng vo, ta c:

2TGSD VVk IMckhc, ta c:



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5.5.3. MOSFET KNH CM NG b. Mchphn cc bng cuphn p

Hnh 5.55. Mchrt gn . Hnh 5.54. Mchphn ccphn p

p dngnh l Thvnin v sau tnh tontngt nh

slide chuong5.machphancuctransistor

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