B GIO DC V O TO

I HC QUC GIA THNH PH H CH MINH TRNG I HC S PHM K THUT

KHOA IN IN T B MN IN T

TI:

THIT K V THI CNG M HNH NH PAN TI VI MU

SINH VIN THC HIN : TRN VN NGHA L KHC SINH LP : 95K GIO VIN HNG DN : L VIT PH NGUYN DUY THO

Thng 03 nm 2000

LI NI U

K thut truyn hnh l mt lnh vc c lin quan v h tr vi nhiu ngnh khc nh: Tin hc, y hc, vin thng, qun s...

K thut truyn hnh bao gm qu trnh thu, x l v pht tn hiu hnh nh v m thanh. Qu trnh ny bin i tn hiu quang thnh tn hiu in v cui cng l ti to li thnh tn hiu quang c th hin trn mn hnh.

Nh vy qu trnh hot ng ca mt Ti Vi l mt qu trnh bin i ngc vi qu trnh hot ng my pht v nguyn tc chung.

Do nu hiu su nguyn l hot ng ca Ti Vi th Sinh Vin c th hiu bit v nguyn tc pha pht mt cch c bn nht.

hiu su v Ti Vi th ngoi vic hc l thuyt k thut truyn hnh, Sinh Vin cn phi thao tc vng vng v thc t.

Trn c s M hnh nh pan TiVi mu c chn lm ti phc v cho vic ging dy thc tp k thut truyn hnh sau khi hc l thuyt hoc c th dng minh ha, gii thiu cho Sinh Vin ang hc l thuyt k thut truyn hnh.

Thit K M Hnh nh Pan Ti Vi Mu

A. Mc ch v Yu cu: 1.Mc ch:

Nhm h tr cho vic ging dy l thuyt v thc tp k thut truyn hnh, "M Hnh nh Pan Ti Vi Mu" c th dng minh ho cc mch c bn tng ng vi tng khi theo s khi ca Ti Vi mu hoc to ra cc pan thng dng gip cho sinh vin l lun v bit cch vn dng l thuyt vo cc mch thc t.

(Trong thc t c v s Pan, t mt hin tng hng hc c th do nhiu nguyn nhn gy ra do sinh vin phi nm vng l thuyt k thut truyn hnh c bn v suy lun phn tch mi sa cc pan mt cch khoa hc c)

Ngoi ra m hnh c th dng ging dy thc tp truyn hnh gip sinh vin cng c v hiu r hn l thuyt hc, luyn tp k nng phn tch, l lun t cc pan do Gio Vin to ra trn m hnh.

2. Yu cu:

V m hnh dng cho vic ging dy nn vic thit k mch cn theo cc yu cu sau: - Cc board mch phi ph hp vi cc khi c bn nh l thuyt hc. - Hn ch ti a vic dng cc IC tch hp nhiu khi li vi nhau. - Mch n gin, r rng, d kho st v o c.

- Board mch v m hnh c th tch ra hoc ghp li d dng v c kch thc gn nh.

- Vt t linh kin d tm trn th trng. - Gi thnh tng i c th chp nhn c.

B. tng thit k v phng php thc hin: c th ph hp vi mc ch v yu cu nh trn, m hnh thit k gm 2 phn chnh: 1. Thit k m hnh Ti Vi mu.

2. ng thi vi vic thit k cc board mch hnh thnh tng to ra cc pan.

tng tng qut v "M Hnh nh Pan Tivi Mu" nh sau :

gii quyt cc pan vic u tin cn nhn nh v phn tch hin tng da vo s khi, nh vy cn phi thit k mi khi tng ng vi mt board mch ring (board khi ).

Sau m hnh hot ng cn phi c mt board chnh kt ni cc khi li vi nhau.

1. Mun m hnh hot ng th vic thit k cc board khi phi c thit k v cn chnh trc.

Vic cn chnh cn c cc thit b sau: VOM Oscilloscope 25 MHz, 2 tia. My pht tn hiu hnh chun. My pht sng m tn. B ngun n p thay i c : 1,25VDC 30 VDC/ 2A.

Cc board khi thit k cn c cc im th o in p mt chiu v cc dng sng tn hiu chun.

Sau khi hon thnh vic thit k v cn chnh cc board khi, giai on tip theo l thit k board chnh.

Board chnh gm 2 phn: (A & B)

Board A: Gm cc board khi kt ni li vi nhau thng qua cc cm nh my Vi Tnh. Nhim v board ny l kt ni vi CRT to ra khung sng v hnh nh trn CRT. Board B: Gm cc board khi kt ni li vi nhau thng qua cc cm nh mt my vi tnh. Nhim v board ny c th thu sng t i pht hoc VCR v ng thi iu khin.

2. tng to ra cc pan c hnh thnh t cc board khi nn cng vic ca phn ny l thit k cc board trung gian c cc cng tc chuyn mch bng tay tng ng vi cc pan c th xy ra trong mt board khi.

C. Cc bc thc hin: Cc board khi c thit k da vo s nguyn l ca cc hiu TiVi

khc nhau. Vic thit k cc board khi khng nht thit phi theo trnh t nht nh,

tuy nhin theo l thuyt k thut truyn hnh hc v d dng thc hin m hnh th nn theo cc bc sau:

I. Bc 1: Thit k cc board khi ca board A. to ra khung sng trn mn hnh cn phi c n hnh v cc board mch

tng ng.

- M hnh c th kt ni c vi cc loi n hnh 14 inch c nh nn cn thit k board ngun n p v mch cng sut qut ngang, FBT sao cho ph hp.

- Thit k board H.OSC, V. OSC. - Thit k board cng sut qut dc. - Thit k board khuch i tn hiu sc v mch ghp ni CRT. - Thit k board khuch i tn hiu chi. - Thit k board gii m mu. Kt ni cc board khi trn vi nhau board A hot ng tt.

II. Bc 2: Thit k cc board khi ca board B

Sau khi board A hot ng, cc board khi ca board B s c thit k tip theo trnh t sau:

- Thit k board chuyn mch AV / TV. - Thit k board Tuner.

- Thit k board IF. - Thit k board Audio. - Thit k board vi x l. Kt ni cc board khi trn li vi nhau board B hot ng tt.

III. Bc 3:

Kt ni board A v board B sao cho m hnh hot ng v cn chnh li cho ph hp.

IV. Bc 4:

Thit k cc board trung gian gia cc board khi vi board chnh v trn board trung gian c cc cng tc chuyn mch nh pan.

I. Bc 1: Thit k cc board khi ca board A 1. Thit k board ngun n p ngt dn. Mch c thit k trn mt board ring ( phn diode nn in v t lc

in nm trn board chnh A ) v mch ny c th thay bng 1 board mch hot ng theo nguyn l kiu khc nhng thng s k thut phi ph hp.

an ton cho Sinh Vin khi thao tc thc hnh, mch c thit k mass cch ly.

a. Thng s k thut: - Vin : 130VDC 305VDC - Vout : B+1: 115 V - B+2: 16 V - Pmax : 120 watt - Tn s hot ng ca mch: 30KHz 50 KHz - gn sng trn p mt chiu ( Ripple ) : 100 mVpp b. S khi:

c. S nguyn l:

Phn t chuyn mch

Nn v lc

Dao ng v iu chnh tn s xung

Ap chun

Ap tham chiu

Phn t iu khin

Vi x l

in p DC (sau khi nn in v

lc in)

D sai Phn t cm bin

Nn v lc

Bin p xung cch ly mass

Phn t chuyn mch

FBT

16V

115VDC

R19

C217805

Q8R26

Q?NPN

5V 16V VI X LY 115V VI X LY

d. Tnh ton v thit k mch:

Bin p xung:

Bin p xung hot ng da trn hin tng cm ng in t, li ca bin p l ferit nn tn hao t v hiu sut cao.

- Tnh dng nh cun s cp bin p:

Ipp = 2Po / VImin . max

in p DC nh nht sau khi qua chnh lu:

VImim =100.1.4 =140V

in p DC ln nht sau khi chnh lu:

VI max =260. 1,4 =376V

T s in p vo:

K = 376 / 140 = 2,62

max : chu k lm vic ln nht

Chn max = 0,7

Chu k lm vic nh nht ng vo:

min = max/ (1- max ). K + max = 0,7 / (1- 0,7 ). 2,62 + 0,7 = 0,47 Dng nh cn tnh:

Ipp = 2. 200 / 140. 0,7 = 4,08A Vy chu k lm vic c gi tr trong khong 0,47 n 0,7 khi in p ng vo

thay i trong khong t 140 VDC n 367VDC .

-Tnh chiu di khe h: in cm s cp bin p xung: Lp = VImin .max/Ipp.f Lp =140.0,7/4,08.20 =1,2.103H Th tch hiu dng ca li: Ve = 0,4 Lp. I2pp.108/B2max Chn Bsat = 4000 gauss Suy ra: Bmax =Bsat/ 2 =2000 gauss Suy ra: Ve = 0,4.3,14.10-3.(4,08)2.108 /( 2000)2 Tit din li bin p xung Ae c chn: 0,96cm3 Chiu di khe h:

Lg = Ve/ Ae = 0,63 / 0,96 = 0,64 cm -Tnh s vng dy qun:

S vng dy qun cho mt volt l: N = 108 / K.f.Ae.Bmax Chn K =4 Suy ra n = 108 / 4.20.103.0,96.2000 = 0,7 vng/ Volt S vng cun s cp: Ns =Vo.n =150.0,7 = 80,5 vng Tnh c dy qun: Dng in ti IL l:

IL =P0/ V0 =200/115 = 1,74 A

ng kn dy qun:

D = 1,3.(IL/J)

J : Mt dng in

Chn J = 4 A/ mm2

Suy ra d =11,3 .(1,74/4) =0,75 mm

Vy ta chn c dy t 0,7 n 0,8 mm

Tnh ton mch in:

Chn transistor chuyn mch Q102

Ngun cung cp c tnh vi in p vo ln nht:

VCC =260.2 = 367 VDC

Vy khi Q4 ngng dn th VCE ca Q4 t gi tr 367 VDC

Dng in ng ra cng l dng in ti:

I0 = IL = P0/U0

Tra s ta chn transistor chuyn mch Q4 l 3688

Vy hai ch lm vic th ng vi:

ton1 = d1 / f = 0,82 / 20.103 = 41 s ton2 = d2 / f = 0,34 / 20.103 = 17 s

toff1 = (1/f )/ton1 = (106/20.103 )-17 =3 s

Dng in cun cm phng qua ti:

Ipk1 = 2ILmax.[ 1+ (V0/V ) ] = 2.1,774.[ 1+ (115/140)] = 6,3A

Do vy t lc c gi tr:

C1 = [(IPK1-IL)2.ton1.VImin]/2.VI.IPK1.V0 = [(6,3 - 1,74)2. 41.10-6.140]/2.100.10-3.4,66.115

= 8,23 F C2 = [(IPK2- IL).ton2.VImax]/2.VI.IPK2.V0 = [(4,66-1,74)2.41.10-6.338]/2.100.10-3.6,3.115 = 457 F

m bo an ton ta chn t lc in ng ra c gi tr: 1000 F/180V

Tnh cun cm :

L1 = [(VImin-V0).ton1]/ IPK1 L1 = [(140-115)].41.10-6/6,3 L1 = 162,7 H L2 = [( VImax- V0).ton2/IPK2 = [(338-115).17.10-6/4,46 =717,8 H L2 > L1 nn chn L2 =717,8 H L2 = .m / IPK2 Chn B = 0,4 T S= 0,85cm2 Suy ra: n = L2. IPK2 / B.S = 717,8.10-6.4,66 / 0,4.10-4.0,85 = 98,4 vng

Thi gian ca chu k xung: T = 1 / f =1 / 20.103 = 50 s Thi hng t np y c th ly t 30 n 100 chu k xung

Chn 60 chu k xung, v thi hng s l: = 60. T = 60 .5 = 3000 s

Tnh b lc ng ra: Chn t lc ng ra vi gn sng b nht l: V = 100 mV Ch lm vic ca chu k xung: d = ( V0 + VD) / (VI + VD ) Ch lm vic ca chu k xung vi in p vo thp nht: d1 = (115 + 0,7 ) / ( 140 + 0,7 ) = 0,82 Ch lm vic ca chu k xung vi in p vo ln nht: d2 = ( 115 + 0,7) / (338 + 0,7 ) = 0,34 Mt khc: d = ton / ( ton + toff ) = ton / T =ton .f Suy ra: ton = d / f : Thi gian dn ca transistor chuyn mch toff = ( 1 / f ) - ton : Thi gian ngt ca transistor chuyn mch e. Thit k mch in board ngun n p ngt dn

2. Thit k board cng sut qut ngang v FBT

Board ny c thit k trn board A( Board chnh ). Mch in da vo s nguyn l hc, FBT ca my Thompson. a. Thng s k thut:

- B+: 115 VDC cung cp cho FBT . - Dng tiu th khng ti: 100mA 150 mA (khng c CRT vYoke H)

- Dng tiu th khi c ti: 400mA 500 mA - Bin in p tn hiu fH ( t board H.osc ) vo tng H.drive 1Vpp - Cc in p ra t FBT: (tng ng vi fH = 15khz17khz ) HV = 18 KV 22KV in p Focus = 2 KV 3 KV in p Screen = 500 V 800V

in p cung cp cho khuch i sc ( sau khi qua nn in v lc in ): 200 VDC.

in p cung cp cho cng sut dc ( sau khi qua nn in v lc in):26VDC

in p t tim: 18Vpp 22 VDC in p cung cp cho tng AFC: 15Vpp 25 VDC in p cung cp cho IC nh( memory ): -30 VDC (sau khi qua nn in

v lc in).

b. S khi

c. S nguyn l:

d. Phn tch mch in:

Khuch i thc

Khuch i cng sut

Cun qut dc

Chnh dng xung

Hi tip v mch chi H.osc V.osc

Vi x l V.Blank

H.Blank

Flyback

Bi p

Nn lc

Cun qut ngang

Khuch i cng

sut

Bin p cng

hng

Khuch i thc

FH t mch h.osc

fV

115V

ABL T ng hn ch sng

Mch bo v Heater

200V Khuch i cng sutsc

-30V ti IC nh

Q1C1

R1

C2

Q2

R2

H.Drive

TH.DriveC3 C4 C5

.47

.22

R3

R3

.22

.47

.47C8

C9

C7

R7 R8

R9

VR4

VR5

R6

C6Board Y

Screen

Focus

HV

12V

24V

180V

Heat

Pin D1

Pin D2

Dao ng ngang c a vo cc B ca trans tin khuch i Q1 v Q2, nhim v chnh l phi hp tr khng v tng dng to ra dng tn hiu ph hp vi ng vo ca tng cng sut ngang. 2 t C1, C2 v R1 mc song song vi cun s cp ca bin p, trit tiu dng Ic ca trans thc Q1 khi b mt in t ngt.

Trans dng tng cng sut ngang Q2 dng loi trans ngt dn v n hot ng ch xung c th ng m nhanh. Khi xung dng cp vo cc B ca Q2 th c dng chy qua t .47p. Khi Q2 ngt, dng khng bin mt tc th m gim t t qua t C3, C4, C5, sau t mi bt u x qua cun Yoke vi chiu ngc li trc . Khi t x ht th xung c cp vo cc B ca Q2 v qu trnh hot ng c lp li.

e. Thit k mch in board cng sut ngang v FBT:

Board ny c thit k trn boad chnh A

1 2 3 4 5 6 7 8

9 10 11 12 13 14 15 16

3. Thit k board H.osc, V.osc:

Board ny dng IC LA7800 c dng trong cc TiVi Sanyo IC LA7800 bao gm cc khi: Sync sep, AFC, H.osc, V.osc.

a. Thng s k thut:

- Vcc : 12VDC - Dng tiu th: 20mA 30mA -V.osc out : 1Vpp

- in p tn hiu hnh vo: 1Vpp - fH : 15Khz 17 Khz - fv: 50 Hz 60 Hz - H.osc out: 1 Vpp

b. S khi:

V

Blank V.osc Sync sep AFC

V.drive Shut down

circuit H.osc

c. S nguyn l:

d. phn tch mch in:

Khi c in p B+: 115V t board ngun n p a n ng vo 115V qua R18: 10k/ 5w, chn 15 IC LA 7800 c cp 12V, lc ny khi dao ng ca IC LA 7800 ( chn 2 ) kt ni vi mch in gm R2, R1, C3, v H.Hold (H.Hold iu chnh fH thay i c t 15 khz - 17 kHz ) s hnh thnh mch dao ng to tn hiu xung vung c tn s fH.

Tn hiu xung vung ny c a ra chn 3, cung cp cho mch cng sut ngang v mch FBT hot ng.

ng thi in p B2+: 16V qua in tr cn in cung cp 12V cho khi V.osc v khi sync ca IC LA 7800 hot ng.

Khi V.osc chn 10, chn 11 kt ni vi R14, C10, R15,C15, C12, v V.Hold hnh thnh mch dao ng dc. Khi c cp in 12VDC, mch V.osc dao ng to tn hiu xung vung fv : 50 Hz 60 Hz (bin tr V.Hold iu chnh s thay i c tn s fv), ng ra khi ny (chn s 6) tn hiu

R1C19 C18

R7

C7C1

C3R2

H.HOLD

C4 C8

R4R3

C2

R11R18R10

C6

R8

C5

R9

C11

C13

R13

C16 C17 R5

R15

C15

R14 C10

V.HOLDR23 D6

C12

R12

C14

D3

C27

D1

1 2 3 4 5 6 7 8

10111213141516 9

LA 7800AF

C

H.OU

T

PRT

GND

V.OU

T V.B

LK

Vcc2

SYNC

V.IN

Vcc1

HT1

PAT

SYNC.OUT

H.OUT

AFC IN

+115 V

VID.IN

+12V

HT2

V.OUT

c a n board cng sut dc v (t board dao ng dc ) v tn hiu hi tip v t chn 7, chn 8 ca IC.

Khi c tn hiu hnh ton phn a n chn 14, khi sync sep s tch tn hiu ng b ngang v dc, tn hiu ng b ngang a n khi AFC (bn trong IC). Chn 16 ca IC s nhn tn hiu xung rng ca (t FBT) thng qua mch tch phn R10, C6, R8 so pha. Chn 1 l ng ra khi AFC, tn hiu ra s a n mch H.osc iu chnh tn s v pha sao cho ph hp vi tn s v pha ca tn hiu hnh.

Ngoi ra chn 4 ca IC kt vi R4, C8, D1 s hnh thnh mch bo v qu p. Mch s ct tn hiu fH ng ra, khi in p a n PRT tng ln.

e. Thit k mch in board H.osc, V.osc:

4. Thit k board cng sut dc:

Board ny dng IC PC 1378 thng s dng trong cc Ti Vi Sony, Nec.

a. Thng s k thut:

in p cung cp 24 VDC 27VDC Dng tiu th: 20mA 50mA Bin in p tn hiu vo: 1Vpp Bin in p tn hiu ra: 60 Vpp b. S khi:

c. s nguyn l:

d. Phn tch mch:

Khi cp ngun 24 VDC vo chn 6 v xung fv t board V.osc vo chn 4 ca IC th mch s hot ng. Mch khuch i cng sut dc hot ng lp B nh mt mch khuch i cng sut m tn, do cn c 2 ng hi tip

1 2 3 4 5 6 7

VERT OUT BOOSTER

UPC1378

1 2 3 4 5 6 7

GND

OUTPUT

BST1

Vcc

BST2

INPU

T

ADJ

C23 D5 C29

R22 R24

C26 R28 C25

C28

R29

R27

R26

C21

R25

V.HEIGHT

D4

C9 R20R17

C24

R16

D2 C22

C15

R6

C20

VR

C10

C11

R30C30

uPC 1378

V.BLK OUT

V.OUT1

V.OUT2

V.IN

HT1

+24V

t board ny v chn 7 v chn 8 IC LA 7800 ( t khi V.osc ) n nh ch lm vic.

ng mt: Ng ra chn 2 ra york Vert ng thi qua R6, C20, VR100K v chn 8 IC LA 7800.

ng hai: T u cn li ca York Vert qua mch C28, R29, C21, R27, R26, R25, R20, C9 v bin tr V.Height v chn 7 ca IC LA 78000, bin tr V.Height dng chnh chiu cao ca khung sng.

Tn hiu qut dc xut ra chn s 2 ca IC ti York dc c bin khong 60 Vpp s to t trng lch dc trong cun York dc lm lch tia in t trong ng phng CRT theo chiu dc.

Ngoi ra chn 7 ca IC tn hiu V.Blank thng qua mch R v C ( ni tip) s cung cp cho board mch khuch i Y xo hi v cung cp xung fv cho IC onscreen trn board vi x l.

e. Thit k mch in board cng sut dc:

5. Thit k board khch i sc v mch ghp CRT:

a. Thng s k thut: Ngun cung cp 180 VDC. in p cung cp cc B 3 trans Khuch i sc: 5VDC 7VDC. Bin in p tn hiu Y: 7Vpp Bin in p cung cp t tim 20Vpp ( xung dng ). in p cung cp li G2: 200VDC 500VDC. in p cung cp li G3:( Vo cm ui CRT ): 2KV. Mch hot ng kiu hiu s mu: R-Y, G-Y, B-Y.

b. s nguyn l:

c. Phn tch mch:

L351

R353 R352 R351

Q353 Q352 Q351

100U

10K 2W 10K 2W 10K 2W

R365 680

R368

180

C353

560P

R371

R359

2K8

2K8

2K8R369

C352 R367

R364

R358

C351

R366

R363

R357

R1

C1

Q1

Q2Q3

R2R3

R4R5

R6

B-OUT

G-OUT

R-OUT

PIN G1

PIN G2

PIN G3

PIN G5

PIN G6

PIN G4

PIN G7

PIN G8

Ba tn hiu sc ER, EG, EB ra t IC gii m mu AN5625 c a vo cc B ca Trans cng sut Q353, Q352, Q351 trong lc tn hiu chi -EY da vo cc E ca 3 trans cng sut ni trn.

Ng ra ca Q353, Q352, Q351 qua bin tr VR 2K7 1/2W ti cc C c a thng vo 3 catot n hnh s l ER, EG, EB. Li 1 chung ni mass, li 2 v li 3 cp p dng ly t cun HV.

ng tn hiu chi -EY vo Q351 c gi lm chun hai ng chi Q352 v Q353, c hiu chnh bng 2 bin tr R371 v R369 tc l thay i bin -EY a vo cc E ca Q351 v Q353.

Mc tn hiu a vo cao, c ngha l tn hiu ra cng cao v dng tia ca n hnh cng ln. Thay i 2 chit p nh vy l thay i mc cao nht ca dng tia B v R sao cho chi tit sng nht ca nh ( mc EY cao nht ) th 3 ng phng R, G, B c cng ng t l to ra nh sng trng mt n hnh.

ng thi tn hiu onsreen t vi x l a n R1, C1 vo cc E ca Q1 ly ra cc C ca Q1, vo cc B ca Q2 v ly ra cc C ca Q2. Tn hiu onscreen sau khi qua tng m Q1,Q2 c a t cc C Q2 vo cc B ca Q353 sau a vo KB n hnh.

d. Thit k mch in board khuch i sc v mch ghp CRT

6. Thit k board khch i tn hiu chi:

Mch ny nu s dng IC AN 5615 th mch s n gin hn, tuy nhin rt kh cn chnh v phi hp vi tn hiu vo, v cc khi li tch hp trong IC nn chn gii php s dng trans.

Mch dng trans thit k s phc tp hn nhng vic phi hp tng tr v cn chnh s tr nn d dng hn. a. Thng s k thut:

Vcc: 12VDC. Dng tiu th 10mA 20mA. in p tn hiu vo: 1Vpp. in p tn hiu ra (Y): 7Vpp 10 Vpp. in p tn hiu V.Blank: 20Vpp. in p tn hiu H.Blank vo: 20 Vpp.

b. S nguyn l:

c. Phn tch mch:

6K8 2k2R1

R3

R2

18k R4

2k2

Q1

R5

330

R6

220 R7820

C2L1

C4 R9

390

R32

5K6

R33

330 R34

C7

CONT

RAST

L2

Q3 C6 R10330

L315UC51000P

R8270

R11390

C8

D1 C9 10U R14220

R13

68K

R1218K

R15

1K8

R1715

C11

1500

P

R18680

L5

R16

470

C17 C18

R221K

5

Q5

Q6R20

1KD3 D4

D5

L6

D7

D8C12

D6

R24

6K8 C133U3

R25

C15R30

560

D2

R35

500

Q4

R29

330K

R31

4K7

R36 5K

C16

330P

L4

15m

R27

27K R28

47K

C3

1200

P

R266K8

C14

100U

47U

V.BLANK Y.OUT

CONS

VCC

VIDEO.IN

H.BLANK

ABL

VCC

Tn hiu video composite c a ti Q1, C1 cch ly thnh phn DC t tng trc.

Q1lm nhim v ca tng m, ng ra ca Q1 tn hiu c a n Q2vQ3.

Q2, Q4 l nhim v iu khin thnh phn DC ca tn hiu video, iu chnh mc sng ti trn mn CRT nh bin tr R35

Q3 phi hp vi mch C6, L3, L10 v L1,C2, R7, C1 nng p tuyn tn s cao ca tn hiu chi, ng thi iu chnh bin tr Con trast s lm thay i bin tn hiu chi.

Tn hiu chi t ng ra ca mch Q3 ( thng qua C6 )v thnh phn DC ca tn hiu chi ( Q2, Q4 ) s a n cc B ca Q5.

Ti cc B Q5 p DC t ng ra ABL mch FBT s t ng khng ch ch lm vic ca Q5 khi CRT hot ng qu mnh.

Q5 lm nhim v khuch i o pha tn hiu chi v a ti Q6.

Q6 ng vai tr nh mt tng m ng thi trn cc tn hiu V.Blank ( t board V.Amp ) v H.Blank ( ly t FBT ) xo ng hi ngang v dc trn CRT.

d. Thit k mch in board khuch i tn hiu chi:

7. Thit k board gii m mu: Pan v NTSC a. Thng s k thut:

in p cung cp Vcc: 9 VDC 12VDC ( chn 11 ). Dng tiu th ca board: 40mA 60mA. Cc in p cn thit cung cp cho board mch: Tn hiu hnh mu: 1Vpp ( chn 7 IC ) Xung fH khong 10Vpp ( chn 2 IC ) H.Sync khong 10 Vpp ( chn 14 IC). V.Sync khong 10Vpp ( chn 18 IC ). in p cho phn iu chnh bo ha mu: min 6V (chn 8 IC). in p chnh Tint: 0 VDC - 12 VDC ( chn 9 IC ) in p cung cp chn 19 thay i 3 cp ty theo IC gii m mu h

tng ng : Vcc: H Pal 1/2 Vcc: H NTSC 3,58 0VDC: H NTSC 4,43

b. s khi:

c. s nguyn l:

12

34

56

78

910

11 1213

1415

1617

1819

2021

22

R-Y G-Y B-YMATRIX

SYSTEMSW

BLANK4,43 3,58MHZOSC

BURSGATE

KILLIERDET

1HFF

R-YDEM

B-YDEM

SIFFLINEOSCR1

AFCDET

ACCDET

COLORCONT

BPADELAYLINE MATRIX

TINCONT

C16 115P

R 1 2

5K6

Q2A1

015

R13

6K8 R15 1K2

R14

1K2

C18

1U R32

R31

TIN

COLO

R

VCCVCC

VEDIO IN

d. Phn tch mch:

Phn tch cc khi trong IC:

Tng khuch i cng le c nhim v loi b tn hiu khng cn thit, ch gi li tin tc le mu. Khuch i cng le ch m ra ng lc khi c le mu.

Mch dao ng tn s 4,43 MHz v 3,58 MHz nhm to sng mang ph thc hin vic gii m.

Mch ACC (auto color control ): l mch iu khin tn hiu mu, mch ACC c kt cu ging mch AGC. Nhng tn hiu mch AGC l video v AGC n nh bin video, cn tn hiu ACC l le mu v ACC l mch n nh bin tn hiu sc.

IC gii m mu c s dng trong m hnh l AN5625, trong IC khng c x l tn hiu chi Y.

Nhim v ca tng Killer: khi tng ny d khng thy tn hiu nhn dng Ident ca h mu, n s lm tt mch mu trnh nhiu mu khi thu hnh en trng. Khi mun gii m mu th my thu phi to li c thnh phn sng mang ph mu ( nh mch dao ng ).

Burst gate cn ly xung m cng a vo chn s 14 tch ly tn hiu burst. Phn 1H FF dng o pha sng mang ph theo dng, nh gii m c tn hiu.

Mch Blank ly xung xo, xa ng hi dc v hi ngang n nh hot ng ca mch gii m mu.

Phn tch mch in ca board:

Tn hiu mu tng hp c a n mch ( BPF ) mch cng hng lc ly tn hiu sng mang mu, tn hiu ny a vo chn 7 IC AN 5625 n khi BPA khuch i di thng.

Ng ra khi PBA tn hiu mu qua khi iu khin bo ha ( color control ), iu chnh bin tr color chn 8. Tn hiu c ly ra chn 5 v thng qua VR2, C2 a n chn 3 ng thi qua dy tr ( DL1H ), C4, R18, DL1, C1 n chn 1.

Ti chn 3 tn hiu mu c a n khi burst gate tch tn hiu (burst ) ng b mu khi c xung t Flyback a n. Tn hiu a n APC- det so pha v tn s ca 2 tn hiu : tn hiu to ra t khi dao ng to sng mang ph mu 4,43 Mhz hoc 3,58 Mhz ( chn 15, 16, 17) v tn hiu ng b mu t tn hiu mu tng hp.

Nu c s sai pha th khi APC - det s a tn hiu sai bit v khi dao ng to sng mang ph mu sa sai pha ca tn hiu dao ng cho ng vi pha ca tn hiu ng b mu.

Nu sai tn s hoc sai pha qu nhiu ( ngoi phm vi hot ng ca mch ) khi APC s tc ng vo khi color killer kho mu .

Sau tn hiu ng ra t khi osc 4,43Mhz; 3,58 Mhz s a n khi gii iu ch R-Y, B-Y a n khi Matrix ti to li 3 thnh phn hiu s mu R-Y, B-Y, G-Y v a ra chn 20, 21, 22.

Ngoi ra tn hiu mu t chn 3 cn a n khi system SW ni lin vi chn 19.

Nu chn 19 t trc mc in th bng Vcc (12V) v tn hiu mu a vo l tn hiu Pal 4,43 Mhz qua khi 1HFF th ng ra khi system SW cho ra tn hiu a vo khi Delay Line Matrix v qua khi STFF kt hp vi tn hiu mu qua C2, VR2, v delay 1H a vo chn 1 khi ny hot ng h Pal.

Nu chn 19 c t mc 0 V th mch s hot ng ch gii m NTSC 4,43Mhz.

Nu chn 19 c t mc in th 5V th mch s hot ng ch gii m NTSC 3,58 Mhz.

Khi mch hot ng ch NTSC 3,58 Mhz hoc 4,43 Mhz th chn 9 c ni vi bin tr bn ngoi sa sai pha (bin tr Tint).

Chn 2 nhn tn hiu flyback puls, khi 1H FF hot ng.

Chn 18 nhn tn hiu V. Blank v H.Blank xa ng hi dc v hi ngang.

e. Thit k mch in board gii m mu

II. Thit k cc board khi ca board B:

1. Thit k board chuyn mch TV/ AV:

IC c dng trong board l IC TC 4066 gm 4 cng tc v cc chn iu khin .

a. Thng s k thut:

SW1 chn 1-2 : Chn iu khin 13 -Audio ca TV. SW2 Chn 3-4: Chn iu khin 15 - Video ca TV. SW3 chn 8-9: Chn iu khin 6 - Audio ca VCR. SW4 chn 10-11: Chn iu khin 12 - VideoVCR. in p cung cp: 12V Dng tiu th: Vi mA .

b. s khi:

55 13

2

9

10 11

1

3

8

4

6 12

VI X LY

VI X LY

AUDIO-OUT

VIDEO-OUT

TIVI-AUDIO

TIVI-VIDEO

AUDIO-VCR

VIDEO-VCR

c. s d nguyn l:

d. Phn tch mch:

IC chuyn mch 4066 c 4 cng tc 1 v tr v cc chn iu khin iu khin.

SW1: Chn 1-2 chn iu khin 13 ( Audio Tivi ) SW2: chn 3-4 chn iu khin 5 ( Video Tivi ) SW3: Chn 8-9 chn iu khin 16( Audio VCR ) SW4: chn 19-11 chn iu khin 12 ( Video VCR ) Tn hiu t u my a vo cc E ca Q1 v a ra cc C qua t lin lc C3

n cc B Q2 v ly tn hiu ng pha ra cc E n chn 10 IC chuyn mch (SW4 ).

Tn hiu video t khi khuch i trung tn video n chn s 3 IC chuyn mch.

C5R11 R10 C4

R12 R13

R14

R9R1 C1 R2R3

C2

Q1 R5

R6

C3 R7

R8 R9

Q4

R15

R16

Q6R17R18

R19

R20

1 2 3 4 5 6 7

891011121314

D?

TV VIDEO

Vcc

VIDEO.OUT

Vcc

VIDEO VCR

AUDIO VCR

AUDIO OUT

TV AUDIO

Vcc

VXL

Tn hiu audio sau khi tch sng FM n (SW2) chn s 1 IC chuyn mch (SW1 ).

Tn hiu video out ca u my v ca Ti Vi ra chn 11v chn 4. Hai chn ny c ni chung vi nhau n cc B trans buffer v ly ra cc E a n khi gii m.

Tn hiu audio ca u my v ca Ti Vi ra chn s 9 v chn s 2. Hai chn c ni chung vi nhau v a n khi khuch i m tn v a ra loa.

Hai trans Q5 v Q6 c kt ni nh s . Cc B ca Q5 c iu khin bi khi iu khin. Khi IC iu khin tc ng mc thp th Q5 ngng dn, p Vc Q5 bng VCC tc ng vo chn 5 v chn 13 mc cao lc ny SW2 v SW4 ng li, my lm vic ch u my.

Khi cc B ca Q5 c tc ng mc cao lm Q5 dn mnh, p Vc ca Q5 gim lm Q6 ngng dn, p Vc ca Q6 mc cao gn bng Vcc, tc ng vo chn 6 v chn 12 lm SW1 v SW3 ng li nn my hot ng ch Ti Vi.

Chn 14 : Ni ngun 24V. Chn 7 ni mass.

e. Thit k mch in board chuyn mch Ti Vi / AV

2. Thit k board tuner:

Board ny dng tuner ca my Toshiba, hot ng vi tn s ca IF theo tiu chun OIRT.

a. Thng s k thut:

Cc chn ra ca tuner theo qui c s th t : 1 - IF. 2 - chn trng 3 - B+: in p cung cp 9VDC-12 VDC . 4 - AFT. 5 -SW chuyn mch do board vi x l xut in th iu khin BU hoc

BV. 6 - in p thay i t 0 - 30V t board vi x l cung cp d i. 7 - BU : in p cung cp cho khi UHF trong tuner hot ng. 8 - BV: in p cung cp cho khi VHF low v high hot ng . 9 - AGC: in p AGC t board trung tng cung cp

b. S khi:

3. Thit k board trung tn hnh:

IC c dng thit k l TA 7607.

IF B+ AFT SW VT BUBV AGC

ELECTRONIC TUNER

ANTEN

a. Thng s k thut:

Vcc: 12 V. Dng tiu th: 15 mA. Ng vo cn cung cp: Tn hiu IF t ng ra tuner. Tn s IF. Ng ra cung cp: in p RF AGC cho tuner: 5V 7V. in p AFT cho tuner: 4V 8V. in p tn hiu hnh mu ton phn: 1Vpp. in p SIF: 1Vpp.

b. S khi:

C. S mch:

1 2 3 4 5 6 7 8

910111213141516

IFAMP

RF AGC NOISEINVERT

AFTDET LIMIT

IFAGC

VIDEODET

VIDEOAMP

NOISEINVERT

IC TA 7607

R18

L4L5

C9C1

0

C11

C12

C13

C14C15

8 9

d. Phn tch mch in:

Tn hiu trung tn t IF out ca b tuner qua cun dy L1 v R5 mc song song lc nhiu, sau qua t lin lc C n trans tin khuch i Q1. R4, R6 cu phn th ca Q5.Tn hiu c ly ra cc C ca Q1 qua t lin lc C3 n b lc SAW, lc ly tn hiu IF chun ng thi loi b tn hiu ca cc knh ln cn. Sau tn hiu trung tn a n chn s 1 v 16 ca IC 7607. Tn hiu t chn s 2 v chn s 15 cng a vo tng khuch i trung tn.

Mch LC s cp cho dao ng tn s chun cho mch tch sng qua 2 chn 7 v 8. Khi tch AFT gm mch dao ng LC a vo chn 7 v chn 10 ca IC. Tn hiu t khi AFT ra chn 6 vo mch dao ng trong tuner n nh tn s. Sau tn hiu qua mch lc nhiu vo khi tch sng video, tn hiu ny c khuch i nh khi khuch i tn hiu hnh. Tn hiu hnh ton phn c ly ra chn s 12 ca IC.

Chn 11 cp ngun 12 VDC Chn 13: Mass.

e. Thit k mch in board trung tn hnh

4. Thit k board SIF v cng sut m thanh:

Board SIF:

IC c dng l PC 1382 thng c trong cc TiVi Nec, Sanyo,Toshiba.

a. Thng s k thut:

Vcc: 12 V. Dng tiu th khong 12mA. Ng vo cn cung cp. -Tn hiu SIF (t board SIF ). -in p iu khin khi AFT iu chnh m lng tn hiu audio

(chn 8 ). Ng ra cung cp: - Tn hiu audio cho mch cng sut m thanh.

b. S khi:

1234567

8 9 10 11 12 13 14

DETLPF LIMITER

DRIVEATTVCCGND

UPC 1382

c. S nguyn l mch:

d. Phn tch mch in:

Tn hiu SIF c ly t ng ra khi video, Qua (trap) ting CF2 tng ng vi tn s trung tn ting. Ty theo tn hiu SIF cn s dng, trap CF2 c gi tr tn s tng ng tn s s cho qua, sau tn hiu ny a n chn 14, qua R35 n chn 13 a vo khi Limiter.

ng ra khi ny trung tn ting s qua mch lc thng di (LPF : Low Pass Filter ) v c a qua khi tch sng FM.

Ng ra khi Det tn hiu m tn c tch ra, v ra chn 5 a vo khi ATT ( chn 4 ) sau c a qua khi tin khuch i v ra chn 2 n khi khuch i cng sut m tn ra loa ti to li m thanh.

Chn 8: iu khin m lng volume. Chn 9,10: C thch anh CF3 c tc dng cng hng tn s 6,5 Mhz

tch tn hiu m tn. Chn 1: Cp ngun 12V.

C25

R33

R32R34

C28

C27

C29 C30 R36

CF2L10

C20C21R31 C31

C24 R38 C32C33

1234567

8 9 10 11 12 13 14

DETLPF LIMITER

ATT DRIVE

pin1-1

pin1-2

pin1-3

pin1-4

vcc

Chn 7: Mass.

Board cng sut m thanh:

a. Thng s k thut:

Vcc: 12V. Dng tiu th: 12mA. Cng sut 3 Watt

b. S khi v s nguyn l mch in:

c. Phn tch mch:

IC s dng cho tng cng sut ny l TBA 810. Tn hiu m thanh t chn 2 IC UPC 1382 hoc tn hiu audio t u my qua bin tr volume tng gim tn hiu, sau qua t lin lc C9 vo chn 8 IC. Chn 7 c t C8 xung mass. Chn 1 l chn cp ngun 12V, C1: t lc ngun, chn 9 v chn 10 ni mass.

Tn hiu sau khi qua khi khuch i trong IC c ly ra chn 4 qua t sut m C4 lm thnh mch hi tip.

12

TBA 810

1110 9

876

54

32

1VCC

C3 100

UF

R4

110K

C9

1UF

VOLUME

C7

R356C6

331C5

332

C4470

C3104R2

R1 100C1

470

PIN 3

PIN 1

PIN 2

e. Thit k mch in board SIF v cng sut m thanh

e1. Thit k mch in board SIF

e2. Thit k mch in board cng sut m thanh

5. Thit k board vi x l:

board ny s dng vi x l MN 14838, IC nh MN 1224, IC thc hin chc nng Inverter v IC thc hin chc nng giao tip LA7930.

a. Thng s k thut:

Thng s ng ra: Cung cp in p d i BT cho khi Tuner. Xut cc in p iu khin: BU, BVH, BVL.

Chuyn i Ti Vi/ AV Ngun m lng volume

Xut tn hiu onscreen a ln board CRT dng hin th. Thc hin chc nng nh knh khi d i.

Thng s nhg vo:

Cung cp cc loi ngun: 5V, 16V, -30V. Xung fH, fV : a vo thc hin chc nng ng b gii m. Vi x l hot ng vi tn s xung clock 500 khz. Dng tiu th t 60mA - 80 mA

b. S khi vi x l:

c. S nguyn l:

VI X

U LY

148

38

MEMORY

MN1

224

IC N

GOAI V

ILA

7930

DATA BUS

ADDRESS BUSS

CONTROL BUS

d. Phn tch mch:

board vi x l hot ng th vic u tin cn cp ngun 5V, ngun ny c ly t IC 7805 ca board ngun v ngun -30V, 15V cp trc cho board vi x l.

Khi IC vi x l hot ng, nu tc ng vo cng tc S701 th chn 14 ca vi x l xut 5V n trans Q5, trans Q8 ca board ngun n p xung. Hai trans Q5, Q8 dn bo ha th ngun B+1: 115V v B+2: 16V s cung cp cho ton m hnh hot ng.

Khi m hnh hot ng th vic iu khin cc chc nng nh: - Volume ( iu khin m lng ) tc ng S2, S4. - Chuyn knh: Tc ng S1, S3. - Chuyn trng thi TV / AV S702. - On - off: S701.

- D i: u tin nhn SW2 sau tc ng S712 v S710 nh knh va d i xong cn nhn S711.

IC memory cn cung cp cc ngun in p 5V cho chn 2 v ngn -30 V cho chn 3.

IC giao tip MB 88301 cn cung cp cc ngun in p: 5V cho chn 16. IC ny c nhim v bin i cc lnh xut ra t IC vi x l thnh cc mc in p cung cp cho cc board trn m hnh .

IC vi x l M50435 - 893FP thc hin cc chc nng: - Chuyn mch VL ( chn 25 ), VH ( chn 24 ), VHF ( chn 23 ) - Chuyn TV/AV ( chn 18 - 16 ) - Onscreen (chn 3,4 ) - On/ off ( chn 14 ) - Volume ( chn 27 )

e. Thit k mch in board vi x l:

III. Kt ni board A v board B:

Kt ni board A v board B sao cho m hnh hot ng v cn chnh li cho ph hp.

1. Boad A: S v tr cc board khi trn board A

Board cng sut ngang v FBT

Board ngun n p xung

Board dao ng dc

Board chi

Board gii m

Board cng sut dc

2. Board B: S v tr cc board khi trn board B

Board Tuner

Board chuyn mch AV

Board vi x l

Board trung tn hnh

Board SIF v m thanh

IV. Bc 4: Thit k cc board trung gian gia cc board khi vi board chnh v trn board trung gian c cc cng tc chuyn mch nh pan

1. tng thit k v nguyn tc lm vic:

Vic thit k cc board trung gian nh cc pan thng dng c thc hin sau khi 2 board A v B c cn chnh v kt ni cho m hnh TV hot ng tt.

Cc board trung gian thc cht l board ni gia cc board khi vi board A hoc board B. Trn board ny cc ng ni t board khi xung board A hoc board B thng qua cc cng tc chuyn mch chuyn v tr ng hoc h.

T s xut hin cc pan do Gio Vin t ra, Sinh Vin cn o c v lin h vi kin thc K Thut Truyn Hnh hc.

2. Mt s v d c th vic thc hin cc pan trn mt s board c bn

i vi board dao ng V.osc, H.osc

Cng tc SW1 h: Board mt ngun H.osc m hnh ngng hot ng.

Cng tc SW2 ng: Mass (thng qua trans) th mt H.pulse hnh nh b mt ng b ngang.

Cng tc SW3 h: Mt tn hiu V.osc dn n board cng sut dc, hin tng cn ng sng ngang trn n hnh.

Cng tc SW4 ng: Tn hiu H.osc out ( thng qua trans) b mt cng dn n m hnh ngng hot ng do mt HV.

Cng tc SW5 h: Mt tn hiu video t board chuyn mch AV a n, hin tng mt ng b ngang v dc trn mn hnh.

i vi board cng sut dc:

Cng tc SW6 h: Mt ngun 24VDC cung cp, hin tng cn ng sng ngang trn board mn CRT.

Cng tc SW7 h: Mt tn hiu V.osc t board dao ng V.osc, hin tng cn ng sng ngang trn CRT.

Cng tc SW8: H mt ng hi tip trn khung sng CRT hnh b co li mt tuyn tnh.

3. Nh vy Sinh Vin khng th on m v cn c bng cch chuyn mch cc SW, m cn phi o c phn tch d ra cc pan t cc hin tng xut hin trn mn hnh.

Kt lun

M hnh nh pan Ti Vi mu c thc hin vi thi gian, iu kin kh khim tn v kin thc cn nhiu hn ch nn chc chn cn thiu st, chng em rt mong mi nhn c kin xy dng ca qu Thy C, cc bn Sinh Vin ngy cng tin b.

y l mt ti tng i kh vi chng em, nhng c hon thnh l do s hng dn tn tnh ca thy L Vit Ph, thy Nguyn Duy Tho cng vi n lc bn thn Chng Em.

Mt ln na Chng Em xin chn thnh bit n Qu Thy C gip , ging dy trong thi gian hc tp v hon thnh ti.

M HNH NH PAN TI VI MU C THIT K DA TRN

S KHI CN BN CA TI VI MU

TI LIU THAM KHO

- Television Hand Book K.Blain Benson

- Color Tivi Training Manual HOWARD W SAMS - Ti liu ging dy l thuyt v thc tp truyn hnh ca Thy L Vit Ph.

BMC LC

Li ni u

A. Mc ch v yu cu: Trang 1 1. Mc ch 1

2. Yu cu 1

B. tng thit k v phng php thc hin 2 C. Cc bc thc hin 3

I. Thit k cc board khi ca board A 5 1. Thit k board ngun n p ngt dn 5 2. Thit k board cng sut qut ngang v FBT 12 3. Thit k board H.osc, V.osc 16 4. Thit k board cng sut dc 20 5. Thit k board Khuch i sc v mch ghp CRT 23 6. Thit k board khuch i tn hiu chi 26 7. Thit k board gii m mu Pal v NTSC 29 II. Thit k cc board khi ca board B 34 1. Thit k board chuyn mch TV/AV 34 2. Thit k board Tuner 38 3. Thit k board SIF v cng sut m thanh 44 5. Thit k board vi x l 50 III.Kt ni board A vi board B 55 IV.Thit k cc board trung gian 57 1. tng thit k v nguyn tc lm vic 57

2. Mt s v d c th vic thc hin cc pan trn mt s board c bn

Kt lun