A cikin ƙirar PCB, daidaitawar wutar lantarki (EMC) da tsoma baki na lantarki (EMI) a al'adance sun kasance manyan ciwon kai guda biyu ga injiniyoyi, musamman a cikin ƙirar hukumar da'ira ta yau da fakitin abubuwan da ke ci gaba da raguwa, OEMs suna buƙatar tsarin saurin gudu.A cikin wannan labarin, zan raba yadda ake guje wa matsalolin lantarki a ƙirar PCB.
1. Magana da daidaitawa shine abin da ake mayar da hankali
Daidaitawa yana da mahimmanci musamman don tabbatar da kwararar da ta dace.Idan halin yanzu ya fito daga oscillator ko wata na'ura mai kama da ita, yana da mahimmanci musamman a kiyaye abin da ke yanzu keɓanta daga saman ƙasa, ko kuma kiyaye halin yanzu daga aiki daidai da wani jeri.Sigina masu saurin sauri guda biyu a layi daya na iya haifar da EMC da EMI, musamman crosstalk.Yana da mahimmanci a kiyaye hanyoyin resistor a matsayin gajere kamar yadda zai yiwu kuma hanyoyin dawowa a matsayin gajere kamar yadda zai yiwu.Tsawon hanyar dawowa ya kamata ya zama daidai da tsawon hanyar watsawa.
Ga EMI, hanya ɗaya ana kiranta "hanyar keta" ɗayan kuma "hanyar wanda aka azabtar".Inductive da capacitive coupling yana rinjayar hanyar "wanda aka azabtar" saboda kasancewar filayen lantarki, don haka yana haifar da ci gaba da juyawa a kan "hanyar wanda aka azabtar".Ta wannan hanyar, ana haifar da ripple a cikin ingantaccen yanayi inda watsawa da karɓar tsayin siginar kusan daidai suke.
A cikin ma'auni mai ma'auni mai daidaituwa tare da daidaitacce, magudanar ruwa da aka jawo ya kamata su soke juna, ta haka za su kawar da zance.Amma, muna cikin duniya ajizai da irin wannan abu ba ya faruwa.Don haka, manufarmu ita ce, dole ne a kiyaye mafi ƙarancin magana don kowane jeri.Za'a iya rage girman tasirin crosstalk idan nisa tsakanin layin layi daya ya ninka nisa na layin.Misali, idan fadin layin yana mil 5, mafi ƙarancin tazara tsakanin layi biyu masu layi daya yakamata ya zama mil 10 ko mafi girma.
Yayin da sabbin kayan aiki da abubuwan haɗin gwiwa ke ci gaba da bayyana, dole ne masu zanen PCB su ci gaba da tuntuɓar EMC da matsalolin tsangwama.
2. Decoupling capacitors
Yankewar capacitors suna rage tasirin da ba a so na crosstalk.Ya kamata su kasance tsakanin fitilun wuta da ƙasa na na'urar, wanda ke tabbatar da ƙarancin AC kuma yana rage hayaniya da magana.Don cimma ƙarancin rashin ƙarfi a kan kewayon mitar mai faɗi, yakamata a yi amfani da capacitors da yawa.
Muhimmiyar ka'ida don sanya capacitors na decoupling shine cewa ana sanya capacitor tare da mafi ƙarancin ƙimar ƙarfin aiki a kusa da na'urar gwargwadon yiwuwa don rage tasirin inductive akan jeri.Ya kamata a sanya wannan musamman capacitor kusa da fitilun wutar lantarki na na'urar ko hanyar tseren wutar lantarki kuma ya kamata a haɗa pads na capacitor kai tsaye zuwa ta hanyar ruwa ko matakin ƙasa.Idan jeri yana da tsawo, yi amfani da tayoyi masu yawa don rage rashin ƙarfi na ƙasa.
3. Grounding PCB
Wata muhimmiyar hanya don rage EMI ita ce zana PCB grounding Layer.Mataki na farko shi ne a sanya wurin da ake saukar da ƙasa ya zama babba kamar yadda zai yiwu a cikin jimillar yanki na hukumar PCB ta yadda za a iya rage fitar da hayaki, magana da hayaniya.Dole ne a ɗauki kulawa ta musamman lokacin haɗa kowane sashi zuwa madaidaicin ƙasa ko shimfidar ƙasa, ba tare da wanda ba za'a iya amfani da tasirin neutralizing na abin dogara ba.
Ƙirar PCB ta musamman tana da ƙarfin ƙarfin ƙarfi da yawa.Da kyau, kowane irin ƙarfin lantarki yana da nasa madaidaicin shimfidar ƙasa.Koyaya, yawancin shimfidar ƙasa zai ƙara farashin masana'anta na PCB kuma suyi tsada sosai.Amincewa shine a yi amfani da shimfidar ƙasa a wurare daban-daban uku zuwa biyar, kowanne daga cikinsu yana iya ƙunsar sassan ƙasa da yawa.Wannan ba wai kawai yana sarrafa farashin masana'anta na hukumar ba, har ma yana rage EMI da EMC.
Tsarin ƙasa mai ƙarancin ƙarfi yana da mahimmanci idan ana so a rage girman EMC.A cikin PCB multilayer ya fi dacewa a sami abin dogara mai tushe maimakon ma'aunin ma'auni na jan karfe (satar jan karfe) ko tarwatsewar shimfidar ƙasa kamar yadda yake da ƙarancin ƙarfi, yana ba da hanyar yanzu kuma shine mafi kyawun tushen sigina.
Tsawon lokacin da siginar ke ɗauka don komawa ƙasa shima yana da mahimmanci.Lokacin da aka ɗauka don sigina don tafiya zuwa kuma daga tushen dole ne ya kasance kwatankwacinsa, in ba haka ba wani abu mai kama da eriya zai faru, yana ba da damar hasken wuta ya zama wani ɓangare na EMI.Hakazalika, daidaitawar na yanzu zuwa / daga siginar siginar ya kamata ya zama takaice kamar yadda zai yiwu, idan tushen da hanyoyin dawowa ba su da tsayi daidai, bounce ƙasa zai faru kuma wannan zai haifar da EMI.
4. Guji kwana 90°
Don rage EMI, daidaitawa, vias da sauran abubuwan da aka gyara ya kamata a kauce masa don samar da kusurwa 90 °, saboda kusurwar dama zai haifar da radiation.Don kauce wa 90 ° kwana, jeri ya kamata a kalla biyu 45 ° kwana wayoyi zuwa kusurwa.
5. Yin amfani da ramuka mai yawa yana buƙatar yin hankali
A kusan dukkanin shimfidu na PCB, dole ne a yi amfani da tayoyin don samar da haɗin kai tsakanin yadudduka daban-daban.A wasu lokuta, suna kuma haifar da tunani, yayin da halayen halayen halayen ya canza lokacin da aka ƙirƙiri vias a cikin jeri.
Har ila yau, yana da mahimmanci a tuna cewa vias yana ƙara tsawon lokacin daidaitawa kuma yana buƙatar daidaitawa.A cikin yanayin jeri daban-daban, ya kamata a guje wa ta hanyar inda zai yiwu.Idan ba za a iya guje wa wannan ba, ya kamata a yi amfani da tazarar a duka jeri-jefi don rama jinkirin sigina da dawowar hanyoyin.
6. igiyoyi da garkuwar jiki
Kebul ɗin da ke ɗauke da da'irori na dijital da igiyoyin analog na iya haifar da ƙarfi da inductance na parasitic, yana haifar da matsaloli masu alaƙa da EMC da yawa.Idan an yi amfani da igiyoyin murɗaɗɗen igiyoyi guda biyu, ana kiyaye ƙaramin matakin haɗin gwiwa kuma ana kawar da filayen maganadisu.Don manyan sigina na mita, dole ne a yi amfani da igiyoyi masu kariya, tare da ƙasan gaba da baya, don kawar da tsangwama na EMI.
Kariyar jiki shine lullube gaba ɗaya ko ɓangaren tsarin a cikin kunshin ƙarfe don hana EMI shiga da'ira na PCB.Wannan garkuwa yana aiki kamar rufaffiyar, capacitor mai sarrafa ƙasa, yana rage girman madauki na eriya da ɗaukar EMI.
Lokacin aikawa: Nuwamba-23-2022