MuPCB Dhizaini, Electromagnic Kuenderana (EMC) uye EMI) Agara ari matambudziko maviri ekurongedza, kunyanya muCirthit Board

1. Crosstalk uye wiring ndiyo kiyi pfungwa

Iyo wiring inonyanya kukosha kuve nechokwadi chekuyerera kwakajairika kweazvino. Kana iyo yazvino ichibva kune imwe oscilllator kana chimwe chidimbu chakafanana, chinonyanya kukosha kuti chengetedzwe nacho kunze kwendege yepasi, kana kuti kwete kurega iyo yazvino kumhanya kuenderana neimwe trace. Maviri akaenzana ekumhanya-kumhanya masaini anogadzira EMC uye EMI, kunyanya crosstalk. Iyo yekupikisa nzira inofanira kunge iri pfupi, uye kudzoka kwenzira ino inofanira kunge iri pfupi sezvinobvira. Kureba kwenzira yekudzoka inofanirwa kunge yakafanana nehurefu hwekutevera trace.

Kuna EMI, imwe inonzi "inokandwa wiring wiring" uye imwe ndeye "wiring wiring wiring". Iko kuwirirana kwekunyengedza uye kugona kukonzera iyo "akabatwa" trace nekuda kwekuvapo kweminda yemagetsi, nekudaro inounza mafungu epamberi uye anodzosera kumashure "akabatwa". Mune ino kesi, ripples ichaburitswa munzvimbo yakasimba uko kureba kwekutapurirana uye kugariswa kwechiratidzo chakangofanana.

Mune zvakaringana uye yakagadzikana nguva yemarara marara, mafungu akaomeswa anofanira kudzima mumwe nemumwe kuti apedze crosstalk. Nekudaro, isu tiri munyika isina kukwana, uye zvinhu zvakadaro hazviitike. Naizvozvo, chinangwa chedu ndechekuchengeta crosstalk zvese zvinoteedzana kusvika zvishoma. Kana upamhi hwakareba pakati pemitsetse yakafanana neyakaipisisa yemitsetse, mhedzisiro ye crosstalk inogona kuderedzwa. Semuenzaniso, kana iyo trace upamhi ndeye mashanu mils, iyo shoma chinhambwe pakati pezvikamu zviviri zvinoenderana nekumhanya kunofanirwa kunge kuri gumi mils kana kupfuura.

Sezvinyorwa zvitsva uye zvikamu zvitsva zvinoramba zviripo, PCB Vagadziri vanofanirwa kuramba vachibata neElectromagnetic zvinoenderana uye yekuvhiringidza nyaya.

2. Deacupling Capacitor

Decupurling Capacitors inogona kuderedza mhedzisiro yakashata ye crosstalk. Ivo vanofanirwa kuve pakati pemagetsi ekupa pini uye iyo pasi pen yeiyo mudziyo kuti uve nechokwadi chekusveta accedance uye kuderedza ruzha uye crosstalk. Kuti uwane kuderera kwekushomeka pamusoro pehuremu hwakawanda hwekugara, dzakawanda decoupling capacitors dzinofanira kushandiswa.

Nheyo yakakosha yekuisa decoupling capacitors ndeyekuti iyo capacitor neiyo diki yekugona kugona kukosha inofanira kunge iri pedyo nepaunogona kuderedza iyo yekudzora maitiro ekunyepedzera. Iyi chaiyo capacitor iri pedyo sezvinobvira kune iyo Simba Pin kana Simba trace yechishandiso, uye batanidza iyo Pad yeCaCacitor zvakananga kune iyo kana ndege yepasi. Kana iyo trace izere, shandisa akawanda vias kuti uderedze kusakundikana kwepasi.

3. Ground iyo PCB

Nzira yakakosha yekudzora EMI ndeyekugadzira PCB pasi ndege. Nhanho yekutanga ndeyekugadzirisa nzvimbo yakakura sezvinobvira mukati meiyo nzvimbo yakazara yePCB Dunhu Bhodhi, iyo inogona kuderedza kubuda, crosstalk uye ruzha. Kuchengetwa kwakakosha kunofanirwa kutorwa kana uchibatanidza chimwe nechimwe chikamu kune pasi pasi kana ndege yepasi. Kana izvi zvisingaitwe, kusarerekera kwemhedzisiro yendege yakavimbika pasi haina kuzoshandiswa zvizere.

Iyo inonyanya kuoma PCB dhizaini ine akati wandei akawandisa voltages. Zvakakodzera, imwe neimwe yekunyorwazve yenhamba ine ndeyako inoenderana ndege. Nekudaro, kana pasi pevhu rakawandisa, rinowedzera mutengo wekugadzira PCB uye ita kuti mutengo wakanyanya. Iko kukanganisika ndeye kushandisa pasi pezvirongwa mumatatu kusvika mashanu kusvika mashanu, uye ndege imwe neimwe yepasi inogona kuve nezvikamu zvakawanda zvakawanda. Izvi hazvingori chete kudzora mutengo wekugadzira redunhu bhodhi, asi zvakare inoderedza EMI uye EMC.

Kana iwe uchida kuderedza EMC, yakaderera isina kukodzera kugadzirisa system yakakosha. Mune yakawanda-layer PCB, zvakanaka kuti uve neyekuvhara nzvimbo yakavimbika, pane kubheka kwemhangura kana yakapararira ndege, nekuti ine yakaderera, inogona kupa nzira yazvino, ndiyo yakanyanya kuratidzira chiratidzo.

Kureba kwenguva iyo chiratidzo chenguva chadzoka pasi zvakare chakanyanya kukosha. Iyo iri pakati pechiratidzo uye sosi yemuratidzo inofanira kuve yakaenzana, neimwe nzira ichabereka antenna-senge phenomenon, ichigadzira simba rakapenya chikamu cheEMI. Saizvozvo, iyo inotsvaga iyo inoendesa zviripo kuenda / kubva kune chiratidzo sosi inofanirwa kunge iri pfupi sezvinobvira. Kana kureba kwenzira yetsiva uye nzira yekudzoka haina kuenzana, pasi richaitika, iro rinozopawo EMI.

4. Ngwarira 90 ° Angle

Kuti uderedze EMI, dzivisa wiring wiring, zvinoshandiswa uye zvimwe zvikamu zvinoumba 90 °, nekuti angles kurudyi anozopa rimiation. Pakona iyi, kugona kuchawedzera, uye hunhu hwekusavimbika huchachinjawo, zvichitungamira pakuratidzira uye ipapo EMI. Kuti udzivise makore makumi mapfumbamwe °, matanho anofanirwa kutakurwa kumakona kanokwana pane maviri makumi mana °.

5. Shandisa vias uine yambiro

Muchinenge zvese PCB marongero, vias inofanira kushandiswa kupa hukama hwekugadzirisa pakati pezvivakwa zvakasiyana. PCB yemutungamiriri weinjiniya anofanirwa kuve anonyanya kungwarira nekuti vias anozoburitsa kukosha uye kugona. Mune zvimwe zviitiko, ivo vanogadzirawo kuratidzwa, nekuti hunhu hwekutsigirwa huchachinja apo via vanoitwa muchirume.

Rangarirawo kuti vias vanozowedzera kureba kweiyo trace uye kuda kuenzaniswa. Kana iri trace trace, vias inofanira kudzivirirwa zvakanyanya sezvinobvira. Kana ikasakwanisa kudzivirirwa, shandisa vias mune zvese zvinoitika kuti ubhadhare kunonoka mune chiratidzo uye kudzoka.

6. Cable uye nhovo yekuchengetera muviri

Mabote akatakura digital zvitupa uye analog mafungu anogadzira parasitic kugona uye kureverera, zvichikonzera matambudziko mazhinji eMC. Kana tambo yakapetwa-yakapetwa ikashandiswa, huwandu hwekudyidzana huchachengetwa zvakaderera uye iyo yakagadzirwa magineti inozobviswa. Kuti uwane masaini edzimhosva, tambo yakachengetedzwa inofanira kushandiswa, uye kumberi uye kumashure kwetambo inofanirwa kuve yakadzika kuti ubvise EMI kupindira.

Kuchengetedzeka kwepanyama ndiko kuputira iyo yakazara kana chikamu chehurongwa nesimbi yesimbi kudzivirira EMI kupinda nePCB dunhu. Rudzi urwu rwekuchengetedzeka rwakafanana nemudziyo wakavharwa, unoderedza iyo antenna loop saizi uye inobata EMI.