Unoziva here kugadzirisa dambudziko reEMI kana multi-layer PCB dhizaini?
Rega ndikuudze!
Pane nzira dzakawanda dzekugadzirisa matambudziko eEMI.Mazuva ano EMI kudzvinyirira nzira dzinosanganisira: kushandisa EMI kudzvanya coating, kusarudza yakakodzera EMI kudzvinyirira zvikamu uye EMI simulation dhizaini.Kubva pane yakanyanya kukosha PCB dhizaini, bepa rino rinokurukura nezve PCB stack mukudzora EMI radiation uye PCB dhizaini hunyanzvi.
bhazi remagetsi
Iko kubuda kwemagetsi kusvetuka kweIC kunogona kukwidziridzwa nekuisa capacitance yakakodzera pedyo nepini yemagetsi yeIC.Zvisinei, uku hakusi kupera kwedambudziko.Nekuda kweiyo shoma frequency mhinduro ye capacitor, hazvigoneke kuti iyo capacitor ibudise iyo harmonic simba rinodiwa kutyaira iyo IC inobuda zvakachena mu yakazara frequency bhendi.Uye zvakare, iyo yenguva pfupi voltage inoumbwa pabhazi remagetsi inokonzeresa kudonha kwevoltage kumativi ese maviri eiyo inductance yenzira yekubvisa.Aya mavheti enguva pfupi ndiwo akajairika maitiro EMI kupindira masosi.Tingagadzirisa sei matambudziko aya?
Panyaya yeIC pabhodhi redu redunhu, simba remagetsi rakakomberedza IC rinogona kuonekwa seyakanaka yepamusoro-frequency capacitor, iyo inogona kuunganidza simba rakasvibiswa ne discrete capacitor inopa simba guru-frequency simba rekubuda kwakachena.Mukuwedzera, iyo inductance yesimba rakanaka resimba idiki, saka chiratidzo chenguva pfupi chakagadzirwa neiyo inductor zvakare idiki, nekudaro ichideredza yakajairika modhi EMI.
Zvechokwadi, kuwirirana pakati pemagetsi ekugadzirisa magetsi uye IC simba rekupa pini kunofanira kunge kupfupi sezvinobvira, nokuti iyo inokwira yechiratidzo chedhijitari inokurumidza uye inokurumidza.Zviri nani kuibatanidza zvakananga kune padhi iyo IC simba pini iripo, inoda kukurukurwa zvakasiyana.
Kuti udzore zvakajairika modhi EMI, iyo dura remagetsi inofanirwa kunge yakanyatso dhizainiwa peya yemagetsi maseru kuti ibatsire decouple uye ine yakaringana yakaderera inductance.Vamwe vanhu vangabvunza, zvakanaka sei?Mhinduro inotsamira pane dura remagetsi, zvinhu zviri pakati pezvikamu, uye frequency yekushandisa (kureva, basa reI IC kusimuka nguva).Kazhinji, kuparadzaniswa kwezvikamu zvemagetsi i6mil, uye inopindirana ndeye FR4 zvinhu, saka iyo yakaenzana capacitance pa square inch yesimba layer ingangoita 75pF.Zviripachena, iyo diki iyo layer spacing, yakakura iyo capacitance.
Iko hakuna michina mizhinji ine nguva yekusimuka ye100-300ps, asi zvinoenderana nekukura kwazvino kweIC, zvishandiso zvine nguva yekusimuka muchikamu che100-300ps zvichatora chikamu chepamusoro.Kumaseketi ane zana kusvika mazana matatu ePS kusimuka nguva, 3 mil layer spacing haichashandi kune mazhinji maapplication.Panguva iyoyo, zvinodikanwa kutora tekinoroji yedelamination ine interlayer spacing isingasviki 1mil, uye kutsiva iyo FR4 dielectric material nezvinhu zvine high dielectric constant.Ikozvino, ceramics nemapurasitiki akaiswa muhari anogona kusangana nezvinodiwa zvekugadzira zve100 kusvika 300ps kusimuka nguva maseketi.
Kunyangwe zvinhu zvitsva uye nzira dzinogona kushandiswa mune ramangwana, zvakajairika 1 kusvika 3 ns kusimuka nguva maseketi, 3 kusvika 6 mil layer spacing, uye FR4 dielectric zvinhu zvinowanzokwana kubata yakakwirira-yekupedzisira harmonics uye kuita masaini masaini akaderera zvakakwana, ndiko kuti. , yakajairika modhi EMI inogona kudzikiswa yakaderera.Mupepa iri, muenzaniso wekugadzira wePCB akaturikidzana akaturikidzana unopihwa, uye nzvimbo yepakati inofungidzirwa kuva 3 kusvika 6 mil.
electromagnetic kudzivirira
Kubva pakuona kwechiratidzo chekutarisa, nzira yakanaka yekuisa inofanira kunge iri yekuisa zviratidzo zvose mune imwe kana kupfuura, iyo iri padivi pesimba remagetsi kana ndege yepasi.Nokuda kwekupa magetsi, nzira yakanaka yekugadzira inofanira kunge iri iyo simba remagetsi riri pedyo nendege yepasi, uye kureba pakati pesimba remagetsi uye ndege yepasi inofanira kuva shoma sezvinobvira, iyo yatinoti "layer" nzira.
PCB chikamu
Ndeupi rudzi rwemaitiro ekurongedza anogona kubatsira kudzivirira uye kudzvanya EMI?Iyo inotevera layered stacking scheme inofunga kuti magetsi ekupa ikozvino anoyerera pane imwechete layer uye iyo imwechete voltage kana akawanda voltages anogoverwa munzvimbo dzakasiyana dzeiyo imwechete layer.Nyaya yemasimba akawanda emagetsi ichakurukurwa gare gare.
4-ply ndiro
Pane mamwe matambudziko anogona kuitika mukugadzirwa kwe4-ply laminates.Chokutanga pane zvose, kunyange kana chiratidzo chechiratidzo chiri mumucheka wekunze uye simba uye ndege yepasi iri mukati memukati, kureba pakati pesimba remagetsi uye ndege yepasi ichiri yakakura.
Kana mari inodiwa iri yekutanga, nzira mbiri dzinotevera kune yechinyakare 4-ply board inogona kutariswa.Ose ari maviri anogona kuvandudza EMI kudzvanya mashandiro, asi akakodzera chete kune iyo iyo density yezvikamu pabhodhi yakadzikira zvakakwana uye kune nzvimbo yakakwana yakatenderedza zvikamu (kuisa inodiwa coating yemhangura yemagetsi).
Yokutanga ndiyo yakasarudzwa chirongwa.Iwo ekunze akaturikidzana ePCB ese akaturikidzana, uye maviri epakati akaturikidzana chiratidzo / simba maseru.Simba rekupa pane chiratidzo chechiratidzo chinofambiswa nemitsara yakafara, izvo zvinoita kuti nzira yekuvharisa yemagetsi iite yakaderera uye iyo impedance yechiratidzo microstrip nzira yakaderera.Kubva pamaonero eEMI control, iyi ndiyo yakanakisa 4-layer PCB chimiro chiripo.Muchirongwa chechipiri, chikamu chekunze chinotakura simba uye pasi, uye chikamu chepakati chepakati chinotakura chiratidzo.Kana ichienzaniswa neyechinyakare 4-layer board, kuvandudzwa kwechirongwa ichi kudiki, uye iyo interlayer impedance haina kunaka seyeiyo yechinyakare 4-layer board.
Kana iyo wiring impedance ichizodzorwa, iyo iri pamusoro stacking chirongwa inofanira kuchenjerera kuisa wiring pasi pechiwi chemhangura chekupa magetsi uye pasi.Pamusoro pezvo, chitsuwa chemhangura chiri pamagetsi kana stratum chinofanirwa kubatanidzwa zvakanyanya sezvinobvira kuti ive nechokwadi chekubatana pakati peDC uye yakaderera frequency.
6-ply ndiro
Kana iyo density yezvikamu pa4-layer board yakakura, iyo 6-layer plate iri nani.Nekudaro, iyo yekudzivirira mhedzisiro yeimwe stacking zvirongwa mukugadzirwa kwe6-layer board haina kunaka zvakakwana, uye chiratidzo chenguva pfupi chebhazi remagetsi haina kuderedzwa.Mienzaniso miviri inokurukurwa pasi apa.
Muchiitiko chekutanga, magetsi uye pasi zvinoiswa muzvikamu zvechipiri uye zvechishanu maererano.Nekuda kweiyo yakakwira impedance yemhangura yakavharwa magetsi magetsi, hazvina kunaka kudzora yakajairika modhi EMI radiation.Zvisinei, kubva pakuona kwechiratidzo che impedance control, iyi nzira yakarurama kwazvo.
Mumuenzaniso wechipiri, magetsi uye pasi zvinoiswa muzvikamu zvechitatu nechina zvakateerana.Iyi dhizaini inogadzirisa dambudziko remhangura clad impedance yemagetsi.Nekuda kwehurombo hwemagetsi ekudzivirira dhizaini 1 uye layer 6, iyo yekusiyanisa modhi EMI inowedzera.Kana iyo nhamba yemitsara yemitsara pazvikamu zviviri zvekunze idiki uye kureba kwemitsara ipfupi kwazvo (isingasviki 1/20 yeakanyanya harmonic wavelength yechiratidzo), dhizaini inogona kugadzirisa dambudziko rekusiyanisa mode EMI.Mhedzisiro yacho inoratidza kuti kudzvanywa kwemusiyano modhi EMI yakanyanya kunaka kana iyo yekunze yakazadzwa nemhangura uye nzvimbo yemhangura yakavharwa yakadzikwa (yega yega 1 / 20 wavelength interval).Sezvataurwa pamusoro apa, mhangura ichaiswa
Nguva yekutumira: Jul-29-2020
