EMC tsim nyob rau hauv PCB pawg thawj coj saib yuav tsum yog ib feem ntawm kev tsim qauv ntawm txhua yam khoom siv hluav taws xob thiab cov khoom siv hluav taws xob, thiab nws muaj txiaj ntsig zoo dua li lwm txoj hauv kev sim ua kom cov khoom ncav cuag EMC. Lub tshuab tseem ceeb ntawm electromagnetic compatibility tsim yog kev kawm ntawm electromagnetic cuam tshuam qhov chaw. Kev tswj cov electromagnetic emission los ntawm electromagnetic cuam tshuam qhov chaw yog ib qho kev daws teeb meem mus tas li. Txhawm rau tswj cov emission ntawm cov kev cuam tshuam, ntxiv rau txo cov suab nrov ntawm electromagnetic cuam tshuam los ntawm cov txheej txheem ntawm cov khoom siv hluav taws xob cuam tshuam, kev tiv thaiv (nrog rau kev sib cais), lim, thiab cov thev naus laus zis hauv av yuav tsum tau siv dav.

Cov txheej txheem tsim EMC tseem ceeb suav nrog kev siv hluav taws xob tiv thaiv hluav taws xob, cov txheej txheem lim dej hauv Circuit Court, thiab kev saib xyuas tshwj xeeb yuav tsum tau them rau cov qauv hauv av ntawm cov av sib tshooj.

Ib qho, EMC tsim pyramid hauv PCB pawg thawj coj saib
Daim duab 9-4 qhia txog txoj kev pom zoo rau qhov zoo tshaj plaws EMC tsim ntawm cov khoom siv thiab cov tshuab. Nov yog daim duab pyramidal.

Ua ntej tshaj plaws, lub hauv paus ntawm kev tsim EMC zoo yog kev siv cov qauv siv hluav taws xob zoo thiab kev tsim kho tshuab. Qhov no suav nrog kev txiav txim siab txog kev ntseeg siab, xws li kev sib ntsib tsim qauv tshwj xeeb hauv kev lees paub, txoj kev sib dhos zoo, thiab ntau yam kev sim kev tsim kho.

Feem ntau hais lus, cov khoom siv uas tsav cov khoom siv hluav taws xob niaj hnub no yuav tsum tau muab tso rau ntawm PCB. Cov khoom siv no yog tsim los ntawm cov khoom siv thiab cov khoom siv hluav taws xob uas muaj peev xwm cuam tshuam thiab nkag siab rau lub zog hluav taws xob. Yog li, EMC tsim ntawm PCB yog qhov tseem ceeb tshaj plaws tom ntej hauv EMC tsim. Qhov chaw ntawm cov khoom siv nquag, kev sib txuas ntawm cov kab luam tawm, kev sib txuam ntawm impedance, kev tsim hauv av, thiab kev lim dej ntawm lub voj voog yuav tsum tau txiav txim siab thaum tsim EMC. Qee cov khoom siv PCB kuj yuav tsum tau tiv thaiv.

Thib peb, cov kab hluav taws xob sab hauv feem ntau yog siv los txuas PCBs lossis lwm cov khoom siv sab hauv. Yog li ntawd, EMC tsim ntawm lub cable sab hauv nrog rau txoj kev routing thiab shielding yog ib qho tseem ceeb heev rau tag nrho EMC ntawm txhua yam khoom muab.

Yuav ua li cas ua EMC tsim hauv PCB pawg thawj coj saib?

Tom qab EMC tsim ntawm PCB thiab kev tsim cov kab hluav taws xob sab hauv tiav, kev saib xyuas tshwj xeeb yuav tsum tau them rau kev tiv thaiv kev tsim ntawm lub chassis thiab cov txheej txheem ua tiav ntawm txhua qhov khoob, perforations thiab cable los ntawm qhov.

Thaum kawg, yuav tsum tseem tsom rau cov tswv yim thiab cov khoom siv hluav taws xob thiab lwm yam teeb meem kev lim dej.

2. Electromagnetic shielding
Shielding feem ntau yog siv ntau yam khoom siv hluav taws xob, tsim rau hauv ntau lub plhaub thiab txuas nrog lub ntiaj teb kom txiav tawm lub suab nrov ntawm electromagnetic propagation txoj kev tsim los ntawm electrostatic coupling, inductive coupling los yog alternating electromagnetic teb coupling los ntawm qhov chaw. Kev sib cais feem ntau yog siv cov relays, kev rho tawm transformers lossis photoelectric Isolators thiab lwm yam khoom siv los txiav tawm txoj kev nthuav tawm ntawm cov suab nrov ntawm electromagnetic nyob rau hauv daim ntawv ntawm conduction yog characterized los ntawm kev sib cais hauv av system ntawm ob qhov chaw ntawm lub Circuit Court thiab txiav tawm muaj peev xwm ntawm coupling los ntawm. impedance.

Kev ua tau zoo ntawm lub cev tiv thaiv yog sawv cev los ntawm kev tiv thaiv kev ua tau zoo (SE) (raws li qhia hauv daim duab 9-5). Lub shielding efficiency yog txhais raws li:

Yuav ua li cas ua EMC tsim hauv PCB pawg thawj coj saib?

Kev sib raug zoo ntawm electromagnetic shielding efficiency thiab field zog attenuation yog teev nyob rau hauv Table 9-1.

Yuav ua li cas ua EMC tsim hauv PCB pawg thawj coj saib?

Qhov siab dua qhov kev tiv thaiv kev ua tau zoo, qhov nyuaj dua rau txhua qhov 20dB nce. Cov ntaub ntawv ntawm cov cuab yeej siv pej xeem feem ntau tsuas yog xav tau kev tiv thaiv kev ua tau zoo ntawm 40dB, thaum cov khoom siv tub rog feem ntau xav tau kev tiv thaiv kev ua haujlwm ntau dua 60dB.

Cov ntaub ntawv uas muaj hluav taws xob conductivity siab thiab sib nqus permeability tuaj yeem siv los ua cov ntaub thaiv npog. Feem ntau siv cov ntaub thaiv npog yog steel phaj, txhuas phaj, txhuas ntawv ci, tooj liab phaj, tooj liab ntawv ci thiab lwm yam. Nrog rau cov kev cai nruj dua electromagnetic compatibility rau pej xeem cov khoom, ntau thiab ntau manufacturers tau siv txoj kev plating npib tsib xee los yog tooj liab ntawm cov ntaub ntawv yas kom ua tiav shielding.

PCB tsim, thov hu rau 020-89811835

Peb, lim
Filtering yog ib qho txheej txheem rau kev ua cov suab nrov hauv cov suab nrov hauv qhov zaus, muab txoj hauv kev qis rau cov suab nrov electromagnetic kom ua tiav lub hom phiaj ntawm kev cuam tshuam electromagnetic cuam tshuam. Txiav tawm txoj kev uas qhov cuam tshuam propagates raws cov teeb liab kab lossis kab hluav taws xob, thiab kev tiv thaiv ua ke ua ib qho kev cuam tshuam zoo tshaj plaws. Piv txwv li, lub hwj huam lim dej nthuav tawm qhov siab impedance rau lub zog zaus ntawm 50 Hz, tab sis nthuav tawm qhov tsis muaj impedance rau lub suab nrov electromagnetic spectrum.

Raws li cov khoom siv lim dej sib txawv, cov lim dej tau muab faib ua AC lub zog lim, cov teeb liab xaim kab lim thiab decoupling lim. Raws li qhov zaus ntawm lub lim, lub lim tuaj yeem muab faib ua plaub hom lim: low-pass, high-pass, band-pass, thiab band-stop.

Yuav ua li cas ua EMC tsim hauv PCB pawg thawj coj saib?

Plaub, fais fab mov, grounding technology
Txawm hais tias nws yog cov khoom siv thev naus laus zis, xov tooj cua hluav taws xob, thiab cov khoom siv hluav taws xob, nws yuav tsum tau siv los ntawm lub zog hluav taws xob. Lub hwj chim muab faib ua ib qho hluav taws xob sab nraud thiab ib qho hluav taws xob sab hauv. Lub hwj chim mov yog ib qho tseem ceeb thiab loj ntawm electromagnetic cuam tshuam. Xws li qhov cuam tshuam ntawm daim phiaj hluav taws xob, qhov hluav taws xob siab tshaj plaws tuaj yeem siab li kilovolts lossis ntau dua, uas yuav ua rau muaj kev puas tsuaj loj rau cov khoom siv lossis lub cev. Tsis tas li ntawd, lub mains fais fab kab yog ib txoj hauv kev rau ntau yam kev cuam tshuam cov teeb liab los cuam tshuam cov khoom siv. Yog li ntawd, cov khoom siv hluav taws xob, tshwj xeeb tshaj yog EMC tsim ntawm kev hloov hluav taws xob hloov hluav taws xob, yog ib qho tseem ceeb ntawm cov qauv tsim qauv. Cov kev ntsuas muaj ntau yam, xws li cov khoom siv hluav taws xob txuas ncaj qha los ntawm lub rooj vag tseem ceeb ntawm daim phiaj hluav taws xob, AC kos los ntawm daim phiaj hluav taws xob yog ruaj khov, tsis tshua muaj kev lim dej, kev sib cais ntawm lub hwj chim transformer windings, shielding, surge suppression, thiab overvoltage thiab overcurrent tiv thaiv.

Grounding muaj xws li grounding, teeb liab grounding, thiab lwm yam. Kev tsim ntawm lub cev hauv av, kev teeb tsa ntawm cov xaim hauv av, thiab cov impedance ntawm cov xaim hauv av ntawm ntau zaus tsis yog tsuas yog cuam tshuam nrog kev nyab xeeb ntawm cov khoom lossis cov khoom siv, tab sis kuj muaj feem xyuam rau electromagnetic compatibility thiab nws cov cuab yeej ntsuas.

Cov av zoo tuaj yeem tiv thaiv kev ua haujlwm ib txwm muaj ntawm cov cuab yeej lossis cov txheej txheem thiab kev nyab xeeb ntawm tus kheej, thiab tuaj yeem tshem tawm ntau yam kev cuam tshuam hluav taws xob thiab xob laim. Yog li ntawd, kev tsim hauv av yog qhov tseem ceeb heev, tab sis nws kuj yog ib qho nyuaj. Muaj ntau hom kab hauv av, suav nrog hauv av logic, teeb liab hauv av, thaiv av, thiab tiv thaiv av. Grounding txoj kev tseem tuaj yeem muab faib ua ib qho taw qhia hauv av, ntau lub ntsiab lus hauv av, sib xyaw hauv av thiab hauv av ntab. Qhov zoo tshaj plaws hauv av yuav tsum yog xoom lub peev xwm, thiab tsis muaj qhov sib txawv ntawm cov ntsiab lus hauv av. Tab sis qhov tseeb, txhua “hauv av” lossis hauv av xaim muaj kev tiv thaiv. Thaum ib qho tam sim no ntws, qhov hluav taws xob poob yuav tshwm sim, kom lub peev xwm ntawm cov xaim hauv av tsis yog xoom, thiab yuav muaj qhov hluav taws xob hauv av ntawm ob lub ntsiab lus hauv av. Thaum lub Circuit Court yog grounded ntawm ntau lub ntsiab lus thiab muaj cov teeb liab sib txuas, nws yuav tsim ib lub voj hauv av cuam tshuam voltage. Yog li ntawd, kev siv thev naus laus zis hauv av yog qhov tshwj xeeb, xws li cov teeb liab hauv av thiab lub zog hauv av yuav tsum tau sib cais, cov txheej txheem nyuaj siv ntau lub ntsiab lus hauv av thiab cov av sib xyaw.