Ntxiv nrog rau kev xaiv cov khoom siv thiab kev tsim hluav taws xob, zoo luam tawm hauv Circuit Court board (PCB) tsim kuj yog ib qho tseem ceeb heev hauv electromagnetic compatibility. Tus yuam sij rau PCB EMC tsim yog kom txo qhov reflow cheeb tsam kom ntau li ntau tau thiab cia txoj kev reflow ntws mus rau cov kev taw qhia ntawm tus tsim. Cov teeb meem feem ntau rov qab los tam sim no los ntawm cov kab nrib pleb hauv kev siv dav hlau, hloov cov txheej txheem dav hlau siv, thiab cov teeb liab ntws los ntawm qhov txuas. Jumper capacitors lossis decoupling capacitors yuav daws tau qee yam teeb meem, tab sis tag nrho impedance ntawm capacitors, vias, pads, thiab thaiv yuav tsum tau txiav txim siab. Cov lus qhuab qhia no yuav qhia EMC’s PCB tsim thev naus laus zis los ntawm peb yam: PCB txheej txheej txheej txheem, kev txawj teeb tsa thiab cov cai thaiv kab.

PCB txheej txheej txheej txheem

Lub thickness, los ntawm cov txheej txheem thiab cov txheej txheem ntawm cov txheej txheem hauv Circuit Board tsim tsis yog tus yuam sij los daws qhov teeb meem. Zoo txheej txheej txheej yog los xyuas kom meej lub bypass thiab decoupling ntawm lub hwj chim tsheb npav thiab txo qhov voltage nyob rau hauv lub hwj chim txheej los yog av txheej. Tus yuam sij rau kev tiv thaiv electromagnetic teb ntawm lub teeb liab thiab lub hwj chim mov. Los ntawm qhov kev xav ntawm cov teeb liab kab, ib qho zoo txheej txheej yuav tsum tau muab tag nrho cov teeb liab kab nyob rau hauv ib los yog ob peb txheej, thiab cov khaubncaws sab nraud povtseg ntawm lub hwj chim txheej los yog av txheej. Rau cov khoom siv hluav taws xob, cov txheej txheem txheej txheej zoo yuav tsum yog cov txheej txheem hluav taws xob nyob ib sab ntawm cov txheej hauv av, thiab qhov kev ncua deb ntawm lub hwj chim txheej thiab txheej hauv av yog me me li sai tau. Qhov no yog qhov peb hu ua “layering” tswv yim. Hauv qab no peb yuav tham tshwj xeeb txog PCB txheej txheej zoo heev. 1. Lub dav hlau projection ntawm cov hlau txheej yuav tsum nyob rau hauv nws reflow dav hlau txheej cheeb tsam. Yog tias cov txheej thaiv tsis nyob hauv qhov projection ntawm lub dav hlau reflow txheej, yuav muaj cov kab teeb liab tawm sab nraud ntawm qhov projection thaum lub sij hawm xaim, uas yuav ua rau muaj teeb meem “ntug hluav taws xob”, thiab tseem yuav ua rau lub teeb liab voj voog cheeb tsam nce. , uas ua rau muaj zog sib txawv hom hluav taws xob. 2. Sim zam kom tsis txhob teeb tsa cov kab hluav taws xob uas nyob ib sab. Vim tias cov teeb liab sib txuas ntawm cov kab hluav taws xob uas nyob ib sab tuaj yeem ua rau cov teeb liab sib txuas lus, yog tias nws tsis tuaj yeem zam cov kab hluav taws xob uas nyob ib sab, cov txheej txheem sib nrug ntawm ob txheej thaiv kab yuav tsum tau nce kom tsim nyog, thiab cov txheej txheem sib nrug ntawm cov txheej thaiv thiab nws cov teeb liab Circuit Court yuav tsum txo. 3. Cov txheej txheem dav hlau uas nyob ib sab yuav tsum tsis txhob sib tshooj ntawm lawv cov phiaj xwm dav hlau. Vim hais tias thaum lub projections sib tshooj, lub coupling capacitance ntawm cov khaubncaws sab nraud povtseg yuav ua rau lub suab nrov ntawm cov khaubncaws sab nraud povtseg rau ib leeg.

Multilayer board tsim

Thaum lub moos zaus tshaj 5MHz, los yog lub teeb liab nce lub sij hawm tsawg dua 5ns, thiaj li yuav tswj lub teeb liab voj cheeb tsam zoo, ib tug multilayer board tsim feem ntau yuav tsum tau. Cov hauv paus ntsiab lus hauv qab no yuav tsum tau them sai sai rau thaum tsim cov boards multilayer: 1. Cov txheej txheem tseem ceeb (txheej txheej ntawm lub moos, kab tsheb npav, kab hluav taws xob sib txuas, kab xov tooj cua zaus, rov pib teeb liab kab, nti xaiv teeb liab kab thiab ntau yam teeb liab tswj. kab nyob) yuav tsum nyob ib sab ntawm lub dav hlau hauv av, zoo dua ntawm ob lub dav hlau hauv av, xws li Qhia hauv daim duab 1. Cov kab teeb liab tseem ceeb feem ntau muaj hluav taws xob muaj zog lossis cov kab teeb liab tsis tshua muaj siab heev. Kev xaim ze rau lub dav hlau hauv av tuaj yeem txo qhov chaw ntawm lub teeb liab voj, txo cov hluav taws xob siv hluav taws xob lossis txhim kho lub peev xwm tiv thaiv kev cuam tshuam.

Daim duab 1 Cov txheej txheem tseem ceeb yog nyob nruab nrab ntawm ob lub dav hlau hauv av

2. Lub dav hlau fais fab yuav tsum tau thim rov qab mus rau nws lub dav hlau hauv av uas nyob ib sab (tus nqi pom zoo 5H ~ 20H). Kev thim rov qab ntawm lub dav hlau fais fab txheeb ze rau nws lub dav hlau rov qab tuaj yeem tiv thaiv qhov teeb meem “ntug hluav taws xob”.

Tsis tas li ntawd, lub dav hlau ua haujlwm tseem ceeb ntawm lub rooj tsavxwm (lub dav hlau dav siv dav siv ntau tshaj) yuav tsum nyob ze rau nws lub dav hlau hauv av kom txo tau lub voj voog ntawm lub zog tam sim no, raws li pom hauv daim duab 3.

Daim duab 3 Lub dav hlau fais fab yuav tsum nyob ze rau nws lub dav hlau hauv av

3. Txawm hais tias tsis muaj teeb liab kab ≥50MHz ntawm TOP thiab BOTTOM txheej ntawm lub rooj tsavxwm. Yog tias muaj, nws yog qhov zoo tshaj plaws los taug kev cov teeb liab siab zaus ntawm ob txheej txheej dav hlau kom nws cov hluav taws xob mus rau qhov chaw.

Ib txheej board thiab ob txheej txheej board tsim

Rau kev tsim ntawm ib txheej thiab ob-txheej boards, kev tsim cov kab teeb liab tseem ceeb thiab cov kab hluav taws xob yuav tsum tau them nyiaj rau. Yuav tsum muaj cov xaim hauv av nyob ib sab thiab sib npaug rau cov kab hluav taws xob kom txo tau thaj tsam ntawm lub zog tam sim no voj. “Ground Ground Line” yuav tsum tau muab tso rau ntawm ob sab ntawm cov teeb liab tseem ceeb ntawm lub rooj tsav xwm ib txheej, raws li pom hauv daim duab 4. Lub teeb liab tseem ceeb kab projection dav hlau ntawm lub rooj tsav xwm ob txheej txheej yuav tsum muaj thaj tsam loj hauv av. , los yog tib txoj kev raws li lub rooj tsavxwm ib txheej, tsim “Ground Ground Line”, raws li qhia hauv daim duab 5. Lub “guard ground wire” ntawm ob sab ntawm cov kab teeb liab tseem ceeb tuaj yeem txo cov teeb liab voj voog ntawm ib sab, thiab tseem tiv thaiv crosstalk ntawm kab teeb liab thiab lwm yam teeb liab kab.

Feem ntau, txheej txheej ntawm PCB board tuaj yeem tsim raws li cov lus hauv qab no.

PCB layout kev txawj ntse

Thaum tsim lub PCB layout, ua raws li cov qauv tsim ntawm qhov chaw nyob rau hauv ib txoj kab ncaj nraim raws lub teeb liab khiav cov kev taw qhia, thiab sim kom tsis txhob looping rov qab, raws li pom nyob rau hauv daim duab 6. Qhov no tuaj yeem zam cov teeb liab txuas ncaj qha thiab cuam tshuam cov teeb liab zoo. Tsis tas li ntawd, txhawm rau tiv thaiv kev sib cuam tshuam thiab kev sib txuas ntawm cov khoom siv hluav taws xob thiab cov khoom siv hluav taws xob, kev tso chaw ntawm circuits thiab kev teeb tsa ntawm cov khoom yuav tsum ua raws li cov hauv qab no:

1. Yog hais tias “chaw huv si” interface yog tsim los ntawm lub rooj tsavxwm, cov khoom lim thiab cais tawm yuav tsum muab tso rau ntawm qhov kev sib cais ntawm qhov “chaw huv” thiab hauv av ua haujlwm. Qhov no tuaj yeem tiv thaiv cov khoom siv lim lossis cais tawm los ntawm kev sib txuas rau ib leeg los ntawm txheej txheej txheej, uas ua rau cov nyhuv tsis muaj zog. Tsis tas li ntawd, nyob rau ntawm “chaw huv si”, sib nrug los ntawm kev lim dej thiab kev tiv thaiv cov cuab yeej, tsis muaj lwm yam khoom siv tuaj yeem tso. 2. Thaum ntau lub modules muab tso rau hauv tib lub PCB, digital circuits thiab analog circuits, thiab high-speed thiab low-speed circuits yuav tsum tau muab tso rau nyias kom tsis txhob muaj kev cuam tshuam ntawm cov circuits, analog circuits, high-speed circuits, thiab low-speed circuits. Tsis tas li ntawd, thaum muaj high, nruab nrab, thiab qis-ceev circuits nyob rau hauv lub Circuit Court board nyob rau tib lub sij hawm, nyob rau hauv thiaj li yuav tiv thaiv high-frequency Circuit Court suab nrov ntawm radiating sab nraud los ntawm lub interface.

3. Lub lim dej ntawm lub hwj chim input chaw nres nkoj ntawm lub rooj tsav xwm Circuit Court yuav tsum tau muab tso ze rau ntawm qhov sib txuas kom tsis txhob cuam tshuam rau Circuit Court uas tau lim los ntawm kev sib txuas ntxiv.

Daim duab 8 Lub lim Circuit Court ntawm lub hwj chim input chaw nres nkoj yuav tsum tau muab tso rau ze rau lub interface

4. Cov khoom siv lim dej, kev tiv thaiv thiab kev sib cais ntawm lub interface Circuit Court yog muab tso rau ze ntawm lub interface, raws li qhia hauv daim duab 9, uas tuaj yeem ua tiav cov txiaj ntsig ntawm kev tiv thaiv, lim thiab cais tawm. Yog hais tias muaj ob qho tib si lim thiab tiv thaiv Circuit Court ntawm lub interface, lub hauv paus ntsiab lus ntawm kev tiv thaiv thawj zaug thiab tom qab ntawd lim yuav tsum tau ua raws. Vim hais tias cov kev tiv thaiv Circuit Court yog siv rau sab nraud overvoltage thiab overcurrent tsub kom, yog hais tias tus tiv thaiv Circuit Court yog muab tso rau tom qab lub lim Circuit Court, lim Circuit Court yuav puas los ntawm overvoltage thiab overcurrent. Tsis tas li ntawd, txij li cov kev tawm tswv yim thiab cov kab tawm ntawm Circuit Court yuav ua rau tsis muaj zog lim, kev sib cais lossis kev tiv thaiv thaum lawv ua ke nrog ib leeg, xyuas kom meej tias cov khoom siv thiab cov kab tawm ntawm cov lim lim (filter), kev sib cais thiab kev tiv thaiv Circuit Court tsis ua. khub nrog ib leeg thaum layout.

5. Cov hluav taws xob hluav taws xob lossis cov khoom siv hluav taws xob (xws li rov pib dua circuits, thiab lwm yam) yuav tsum nyob deb tsawg kawg yog 1000 mil ntawm txhua ntug ntawm lub rooj tsavxwm, tshwj xeeb tshaj yog cov ntug ntawm lub rooj sib tham.

6. Lub zog cia thiab lub tshuab lim dej ntau zaus yuav tsum tau muab tso rau ze ntawm chav tsev circuits lossis cov khoom siv nrog cov kev hloov pauv loj tam sim no (xws li cov khoom siv hluav taws xob thiab cov khoom siv hluav taws xob ntawm lub hwj chim module, kiv cua, thiab cov relays) kom txo tau qhov chaw ntawm lub voj voog. loj tam sim no voj.

7. Cov khoom siv lim dej yuav tsum tau muab tso rau ntawm ib sab kom tsis txhob cuam tshuam cov lim hluav taws xob ntxiv.

8. Khaws cov khoom siv hluav taws xob muaj zog xws li siv lead ua, siv lead ua oscillators, relays, thiab hloov cov khoom siv hluav taws xob tsawg kawg yog 1000 mils deb ntawm lub rooj sib tham sib txuas. Nyob rau hauv txoj kev no, qhov cuam tshuam tuaj yeem raug hluav taws xob ncaj qha lossis tam sim no tuaj yeem txuas nrog rau cov kab hluav taws xob tawm mus rau sab nraud.

Cov kev cai ntawm kev sib txuas ntawm PCB

Ntxiv nrog rau kev xaiv ntawm cov khoom siv thiab kev tsim hluav taws xob, cov khoom siv hluav taws xob zoo tshaj plaws (PCB) thaiv kuj yog ib qho tseem ceeb heev hauv electromagnetic compatibility. Txij li thaum PCB yog ib qho tseem ceeb ntawm lub cev, kev txhim kho electromagnetic compatibility hauv PCB thaiv yuav tsis coj tus nqi ntxiv rau qhov kawg ntawm cov khoom tiav. Txhua tus neeg yuav tsum nco ntsoov tias qhov kev teeb tsa tsis zoo ntawm PCB tuaj yeem ua rau muaj teeb meem electromagnetic compatibility ntau dua, tsis yog tshem tawm lawv. Feem ntau, txawm tias qhov sib ntxiv ntawm cov lim dej thiab cov khoom siv tsis tuaj yeem daws cov teeb meem no. Thaum kawg, tag nrho lub rooj tsavxwm yuav tsum tau rov ua dua. Yog li ntawd, nws yog txoj hauv kev zoo tshaj plaws los txhim kho PCB kev sib txuas zoo thaum pib. Cov hauv qab no yuav qhia txog qee qhov kev cai dav dav ntawm PCB thaiv thiab tsim cov tswv yim ntawm cov kab hluav taws xob, cov kab hauv av thiab cov kab teeb liab. Thaum kawg, raws li cov kev cai no, kev txhim kho kev ntsuas yog npaj rau cov ntawv luam tawm Circuit Board Circuit Court ntawm lub tshuab cua txias. 1. Kev sib cais ntawm cov kab hluav taws xob ua haujlwm ntawm kev sib cais yog kom txo qis kev sib txuas lus thiab cov suab nrov sib txuas ntawm cov kab hluav taws xob uas nyob ib sab hauv tib txheej ntawm PCB. Lub 3W specification hais tias tag nrho cov teeb liab ( moos, video, suab, rov pib dua, thiab lwm yam) yuav tsum tau muab cais tawm ntawm kab mus rau kab, ntug mus rau ntug, raws li qhia nyob rau hauv daim duab 10. Yuav kom txo tau qhov sib nqus coupling, cov ntaub ntawv hauv av yog muab tso rau ze ntawm lub teeb liab tseem ceeb kom cais cov suab sib txuas uas tsim los ntawm lwm cov kab teeb liab.

2. Kev tiv thaiv thiab shunt kab teeb tsa Shunt thiab kev tiv thaiv kab yog ib txoj hauv kev zoo heev los cais thiab tiv thaiv cov cim tseem ceeb, xws li lub kaw lus moos teeb liab hauv qhov chaw nrov nrov. Nyob rau hauv daim duab 21, lub parallel los yog tiv thaiv Circuit Court nyob rau hauv lub PCB yog nteg nyob rau hauv lub Circuit Court ntawm lub ntsiab teeb liab. Kev tiv thaiv Circuit Court tsis tsuas yog cais cov coupling magnetic flux generated los ntawm lwm cov teeb liab kab, tab sis kuj cais cov cim tseem ceeb ntawm coupling nrog lwm cov teeb liab kab. Qhov sib txawv ntawm txoj kab shunt thiab txoj kab tiv thaiv yog tias txoj kab shunt tsis tas yuav tsum tau txiav tawm (txuas rau hauv av), tab sis ob qho tib si kawg ntawm txoj kab tiv thaiv yuav tsum tau txuas nrog hauv av. Txhawm rau txhawm rau txo qhov sib txuas ntxiv, kev tiv thaiv Circuit Court nyob rau hauv multilayer PCB tuaj yeem ntxiv nrog txoj hauv kev mus rau hauv av txhua ntu.

3. Txoj kab hluav taws xob tsim yog raws li qhov loj ntawm cov ntawv luam tawm Circuit Board tam sim no, thiab qhov dav ntawm lub hwj chim kab yog tuab li ua tau kom txo tau lub voj tsis kam. Nyob rau tib lub sijhawm, ua kom cov kev taw qhia ntawm cov kab hluav taws xob thiab cov kab hauv av sib haum nrog cov kev taw qhia ntawm cov ntaub ntawv xa mus, uas yuav pab txhim kho lub peev xwm los tiv thaiv lub suab nrov. Nyob rau hauv ib lub vaj huam sib luag los yog ob npaug, yog tias cov kab hluav taws xob ntev heev, lub tshuab hluav taws xob sib txuas yuav tsum muab ntxiv rau hauv av txhua 3000 mil, thiab tus nqi ntawm lub capacitor yog 10uF + 1000pF.

Hauv av hlau tsim

Cov hauv paus ntsiab lus ntawm kev tsim cov xaim av yog:

(1) Lub hauv av digital yog sib cais los ntawm cov av analog. Yog tias muaj ob lub logic circuits thiab linear circuits ntawm lub rooj tsavxwm, lawv yuav tsum tau muab cais kom ntau li ntau tau. Hauv av ntawm qhov tsawg-zaus Circuit Court yuav tsum tau grounded nyob rau hauv parallel ntawm ib tug taw tes kom ntau li ntau tau. Thaum qhov kev xaim tiag tiag yog qhov nyuaj, nws tuaj yeem txuas nrog ib nrab ntawm cov koob thiab tom qab ntawd hauv av sib npaug. Lub high-frequency Circuit Court yuav tsum tau grounded nyob rau hauv ntau lub ntsiab lus nyob rau hauv series, lub hauv av hlau yuav tsum luv luv thiab xauj, thiab daim phiaj-zoo li loj-thaj av ntawv ci yuav tsum tau siv nyob ib ncig ntawm lub high-frequency tivthaiv kom ntau li ntau tau.

(2) Cov xaim hauv av yuav tsum yog tuab li ua tau. Yog tias cov xaim hauv av siv cov kab nruj heev, cov av muaj peev xwm hloov pauv nrog kev hloov pauv tam sim no, uas txo qhov kev ua haujlwm ntawm lub suab nrov. Yog li ntawd, cov hlau hauv av yuav tsum tau ua kom tuab kom nws tuaj yeem dhau peb zaug ntawm qhov tso cai tam sim no ntawm cov ntawv luam tawm. Yog tias ua tau, cov xaim hauv av yuav tsum yog 2 ~ 3mm lossis ntau dua.

(3) Cov hlau hauv av tsim ib lub voj kaw. Rau cov ntawv luam tawm uas tsim los ntawm cov digital circuits nkaus xwb, feem ntau ntawm lawv cov grounding circuits yog teem rau hauv loops los txhim kho suab nrov.

Teeb liab kab tsim

Rau cov kab teeb liab tseem ceeb, yog tias lub rooj tsav xwm muaj cov teeb liab sab hauv thaiv txheej, cov kab teeb meem tseem ceeb xws li moos yuav tsum tau muab tso rau hauv txheej txheej sab hauv, thiab qhov tseem ceeb yog muab rau cov txheej txheem xaim uas nyiam. Tsis tas li ntawd, cov kab teeb liab tseem ceeb yuav tsum tsis txhob hla dhau ntawm thaj chaw muab faib, suav nrog kev siv dav hlau qhov khoob uas tshwm sim los ntawm vias thiab pads, txwv tsis pub nws yuav ua rau muaj kev nce hauv cheeb tsam ntawm lub teeb liab voj. Thiab cov kab teeb liab tseem ceeb yuav tsum yog ntau tshaj 3H los ntawm ntug ntawm lub dav hlau siv (H yog qhov siab ntawm kab los ntawm lub dav hlau siv) txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhuam hniav Rau cov kab moos, kab tsheb npav, xov tooj cua zaus kab thiab lwm yam muaj zog hluav taws xob teeb liab kab thiab rov pib dua cov kab teeb liab, nti xaiv cov kab teeb liab, cov kab hluav taws xob tswj cov teeb liab thiab lwm cov kab teeb liab rhiab, ua kom lawv nyob deb ntawm lub interface thiab cov teeb liab tawm. Qhov no tiv thaiv kev cuam tshuam ntawm cov kab hluav taws xob muaj zog ntawm cov kab hluav taws xob los ntawm kev sib txuas mus rau cov kab hluav taws xob tawm thiab tawm sab nraud; thiab tseem zam cov kev cuam tshuam sab nraud coj los ntawm kev cuam tshuam cov kab teeb liab tawm los ntawm kev sib txuas mus rau cov kab teeb liab rhiab, ua rau lub cev tsis ua haujlwm. Cov kab hluav taws xob sib txawv yuav tsum nyob rau tib txheej, sib npaug ntev, thiab khiav mus rau qhov sib npaug, ua kom lub impedance zoo ib yam, thiab yuav tsum tsis txhob muaj lwm txoj hlua ntawm cov kab sib txawv. Vim tias cov hom impedance ntawm cov kab sib txawv ntawm cov kab sib txawv tau ua kom muaj kev sib npaug, nws muaj peev xwm tiv thaiv kev cuam tshuam tuaj yeem txhim kho. Raws li cov kev cai txuas saum toj no, cov ntawv luam tawm ntawm lub tshuab hluav taws xob ntawm lub tshuab cua txias tau txhim kho thiab ua kom zoo dua qub.