Ii-capacitors zokucoca, ii-inductors zendlela eqhelekileyo, kunye namaso azibuthe ngamanani aqhelekileyo kwiisekethe zoyilo ze-EMC, kwaye zizixhobo ezithathu ezinamandla zokuphelisa ukuphazamiseka kombane.
Ngendima yaba bathathu kwisekethe, ndiyakholelwa ukuba zininzi iinjineli ezingaqondiyo, inqaku elivela kuyilo lohlalutyo oluneenkcukacha lomgaqo wokuphelisa ezona zintathu zibukhali ze-EMC.
1.I-capacitor yokucoca
Nangona i-resonance ye-capacitor ayinqweneleki ukusuka kwindawo yokujonga i-high-frequency ingxolo, i-resonance ye-capacitor ayisoloko iyingozi.
Xa i-frequency yengxolo eya kuhluzwa inqunywe, umthamo we-capacitor unokulungiswa ukuze i-resonant point iwele nje kwi-frequency disturbance.
Kubunjineli obusebenzayo, ukuphindaphindwa kwengxolo ye-electromagnetic ekufuneka ihluzwe ihlala iphezulu ukuya kumakhulu e-MHz, okanye nangaphezulu kwe-1GHz.Kwingxolo ephezulu ye-electromagnetic, kuyafuneka ukuba usebenzise i-capacitor engundoqo ukucoca ngokufanelekileyo.
Isizathu sokuba ii-capacitors eziqhelekileyo zingakwazi ukucoca ngokufanelekileyo ingxolo ye-high-frequency kungenxa yezizathu ezibini:
(1) Esinye isizathu kukuba i-inductance ye-capacitor lead ibangela i-capacitor resonance, ebonisa i-impedance enkulu kwi-high-frequency signal, kwaye iyancipha umphumo we-bypass ye-high-frequency signal;
(2) Esinye isizathu kukuba i-parasitic capacitance phakathi kweengcingo ezidibanisa i-high-frequency signal, ukunciphisa umphumo wokucoca.
Isizathu sokuba i-capacitor ye-core inokucoca ngokufanelekileyo ingxolo ephezulu-frequency kukuba i-capacitor engundoqo ayinayo ingxaki yokuba i-lead inductance ibangela ukuba i-capacitor resonance frequency iphantsi kakhulu.
Kwaye i-capacitor ye-capacitor inokufakwa ngokuthe ngqo kwipaneli yensimbi, isebenzisa ipaneli yensimbi ukuze idlale indima ye-high-frequency isolation.Nangona kunjalo, xa usebenzisa i-capacitor engundoqo, ingxaki yokunikela ingqalelo yingxaki yokufakela.
Ubuthathaka obukhulu be-capacitor ye-capacitor kukoyika ukushisa okuphezulu kunye nefuthe lokushisa, obangela ubunzima obukhulu xa udibanisa i-capacitor ye-capacitor kwipaneli yensimbi.
Uninzi lwee-capacitors zonakaliswe ngexesha le-welding.Ngokukodwa xa inani elikhulu le-core capacitors lifuna ukufakwa kwipaneli, nje ukuba kukho umonakalo, kunzima ukuyilungisa, kuba xa i-capacitor eyonakalisiweyo isusiwe, iya kubangela umonakalo kwamanye ama-capacitors asondeleyo.
2.I-inductance yendlela eqhelekileyo
Kuba iingxaki ezijongene nazo i-EMC ziluphazamiso lwemowudi eqhelekileyo, ii-inductors zemowudi eqhelekileyo yenye yezinto ezisetyenziswa ngokuqhelekileyo ezinamandla.
I-inductor yemowudi eqhelekileyo isixhobo imo yokuphazamiseka imo eqhelekileyo kunye ferrite njengoko core, equlathe iikhoyili ezimbini zobungakanani obufanayo kunye nenani elifanayo ujiko symmetrically inxeba kwi ring efanayo ferrite magnetic core ukwenza isixhobo ezine-terminal, leyo. inempembelelo enkulu yokucinezela i-inductance yesiginali yemowudi eqhelekileyo, kunye ne-inductance encinci yokuvuza yesignali yemo yokwahlula.
Umgaqo-siseko kukuba xa imowudi eqhelekileyo ihamba ngoku, i-flux yamagnetic kwindandatho yamagnetic iphakamisa enye kwenye, ngaloo ndlela ibe ne-inductance enkulu, ethintela imowudi eqhelekileyo yangoku, kwaye xa iikhoyili ezimbini zihamba ngendlela eyahlukileyo yangoku, i-magnetic flux. kwindandatho yamagnetic iyacima enye nenye, kwaye akukho phantse i-inductance, ngoko ke imowudi yokwahlukana yangoku inokudlula ngaphandle kokunciphisa.
Ngoko ke, i-inductor yemodi eqhelekileyo inokucinezela ngokufanelekileyo isignali yokuphazamiseka kwemodi eqhelekileyo kumgca olinganiselayo, kodwa ayinayo impembelelo ekuhanjisweni okuqhelekileyo kwesignali yendlela yokwahlukana.
Ii-inductors zendlela eqhelekileyo kufuneka zihlangabezane nezi mfuno zilandelayo xa zenziwe:
(1) Iingcingo ezinxeba kumbindi wekhoyili kufuneka zifakwe i-insulated ukuqinisekisa ukuba akukho breakdown short circuit phakathi kokujika komjikelo phantsi kwesenzo sokugqithisa ngoko nangoko;
(2) Xa ikhoyili ihamba ngomsinga omkhulu ngoko nangoko, undoqo kazibuthe akufuneki ugcwale;
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(4) Ikhoyili kufuneka ihlatywe kumaleko omnye kangangoko kunokwenzeka, ukuze kuncitshiswe i-parasitic capacitance yekhoyili kunye nokwandisa amandla ekhoyili ukuhambisa ukugqithisa okwethutyana.
Phantsi kweemeko eziqhelekileyo, ngelixa unikel' ingqalelo kukhetho lwebhendi yefrikhwensi efunekayo yokucoca, eyona ininzi i-impedance yendlela eqhelekileyo, ngcono, ngoko ke kufuneka sijonge idatha yesixhobo xa ukhetha i-inductor yendlela eqhelekileyo, ngakumbi ngokwe I-impedance frequency curve.
Ukongezelela, xa ukhetha, nikela ingqalelo kwimpembelelo yendlela yokwahlukana kwi-impedance kwi-signal, ngokukodwa igxininise kwi-impedance yemodi yokwahlula, ngokukodwa ukunikela ingqalelo kwii-ports zesantya esiphezulu.
3.I-Magnetic bead
Kwimveliso yesekethe yedijithali inkqubo yoyilo EMC, sihlala sisebenzisa amaso magnetic, izinto ferrite yintsimbi-magnesium ingxubevange okanye intsimbi-nickel ingxubevange, lo mbandela unobuchwephesha obuphezulu bemagnethi, unokuba yi-inductor phakathi kokujija ikhoyili kwimeko ephezulu. ukuphindaphindeka kunye nokumelana okuphezulu okuveliswe ubuncinci besakhono.
Izinto ze-Ferrite zidla ngokusetyenziswa kwii-frequencies eziphezulu, kuba kwii-frequencies eziphantsi iimpawu zabo eziphambili ze-inductance zenza ilahleko kumgca incinci kakhulu.Kwiifrikhwensi eziphezulu, ubukhulu becala luphawu lokusabela kunye nokutshintsha rhoqo.Ukusetyenziswa okusebenzayo, izixhobo ze-ferrite zisetyenziswa njengezithinteli ezihamba rhoqo kwiisekethe zerediyo.
Ngapha koko, i-ferrite ilingana ngcono nokuhambelana nokuchasana kunye ne-inductance, ukuchasana kukufutshane-kujikelezwe yi-inductor kwi-frequency ephantsi, kwaye i-inductor impedance iba phezulu kakhulu kwi-frequency ephezulu, ukuze yonke into yangoku idlule ekuchaseni.
I-Ferrite sisixhobo esidliwayo apho amandla aphezulu-amaxesha aguqulwa abe ngamandla okushisa, okugqitywa yimpawu zayo zokuxhathisa umbane.Amaso kazibuthe eFerrite aneempawu ezingcono zokuhluza amaza aphezulu kunee-inductors eziqhelekileyo.
I-Ferrite iyaxhathisa kwi-frequencies ephezulu, ilingana ne-inductor enomgangatho ophantsi kakhulu, ngoko inokugcina i-impedance ephezulu kuluhlu olubanzi lwamafrikhwensi, ngaloo ndlela iphucula ukusebenza kakuhle kokucoca amaza.
Kwibhendi ye-frequency ephantsi, i-impedance iqulethwe yi-inductance.Kwi-frequency ephantsi, i-R incinci kakhulu, kwaye i-magnetic permeability ye-core iphezulu, ngoko ke i-inductance inkulu.I-L idlala indima enkulu, kwaye ukuphazamiseka kwe-electromagnetic kucinezelwa kukubonakalisa.Kwaye ngeli xesha, ilahleko ye-core magnetic incinci, isixhobo sonke silahleko esiphantsi, iimpawu eziphezulu ze-Q ze-inductor, le inductor kulula ukubangela i-resonance, ngoko ke kwi-band frequency ephantsi, ngamanye amaxesha kunokubakho ukuphazamiseka okuphuculweyo. emva kokusetyenziswa kwamaso kazibuthe ferrite.
Kwibhendi yefrikhwensi ephezulu, i-impedance iqulethwe ngamacandelo okumelana.Njengoko i-frequency inyuka, ukunyanzeliswa kwe-magnetic core kuncipha, okukhokelela ekunciphiseni kwe-inductance ye-inductor kunye nokuncipha kwecandelo lokusabela kwe-inductive.
Nangona kunjalo, ngeli xesha, ilahleko ye-magnetic core iyanda, icandelo lokuchasana liyenyuka, okukhokelela ekonyukeni kwe-impedance epheleleyo, kwaye xa umqondiso we-high-frequency udlula kwi-ferrite, ukuphazamiseka kwe-electromagnetic kufakwe kwaye kuguqulelwe kwifom. yokutshatyalaliswa kobushushu.
Amacandelo okunciphisa i-Ferrite asetyenziswa ngokubanzi kwiibhodi zeesekethe eziprintiweyo, imigca yamandla kunye nemigca yedatha.Ngokomzekelo, i-ferrite suppression element yongezwa kwi-inlet end yentambo yamandla yebhodi eprintiweyo ukucoca ukuphazamiseka okuphezulu.
Iringi kazibuthe ye-Ferrite okanye i-magnetic bead isetyenziswa ngokukodwa ukucinezela uphazamiseko lwe-frequency ephezulu kunye nophazamiseko oluphezulu kwimigca yesignali kunye neentambo zamandla, kwaye iyakwazi ukufunxa uphazamiseko lwe-electrostatic discharge pulse.Ukusetyenziswa kwamaso emagnethi okanye i-chip inductors ikakhulu kuxhomekeke kwisicelo esisebenzayo.
Ii-chip inductors zisetyenziswa kwiisekethe ze-resonant.Xa ingxolo EMI engeyomfuneko kufuneka ukupheliswa, ukusetyenziswa chip amaso magnetic lolona khetho lungcono.
Ukusetyenziswa kwamaso emagnethi kunye ne-chip inductors
Ii-chip inductors:I-Radio frequency (RF) kunye nonxibelelwano olungenazintambo, izixhobo zeteknoloji yolwazi, i-radar detectors, i-electronics ye-automotive, iifowuni zeselula, ii-pagers, izixhobo zomsindo, abancedisi bedijithali bomntu (PDAs), iinkqubo zokulawula ezikude ezingenazintambo, kunye neemodyuli zombane ophantsi.
Chip amaso magnetic:Iisekethe ezenza iwotshi, ukuhluza phakathi kwe-analog kunye neesekethe zedijithali, i-I/O input/output external connectors (ezifana namazibuko e-serial, amazibuko ahambelanayo, izitshixo, iimpuku, unxibelelwano lomgama omde, uthungelwano lwengingqi), iisekethe ze-RF kunye nezixhobo ezinengqondo ezichaphazeleka lula. ukuphazamiseka, ukuhluzwa kwe-high-frequency eyenziwa ukuphazamiseka kwiisekethe zobonelelo lwamandla, iikhomputha, iiprinta, iirekhoda zevidiyo (VCRS), i-EMI yokunciphisa ingxolo kwiinkqubo zikamabonwakude kunye neefowuni eziphathwayo.
Iyunithi ye-bead magnetic yi-ohms, ngenxa yokuba iyunithi ye-bead magnetic ligama ngokuhambelana ne-impedance eyivelisayo kwi-frequency ethile, kwaye iyunithi ye-impedance ikwayi-ohms.
I-DATASHEET ye-magnetic bead iya kubonelela ngokubanzi ngokuphindaphindiweyo kunye neempawu zokuphazamiseka kwegophe, ngokubanzi i-100MHz njengesiqhelo, umzekelo, xa ubuninzi be-100MHz xa uthintelo lwe-bead magnetic lulingana ne-1000 ohms.
Kwibhendi yefrikhwensi esifuna ukuyihluza, kufuneka sikhethe ubukhulu bokuthintela intsimbi yemagnethi, ngcono, ihlala ikhetha i-600 ohm impedance okanye ngaphezulu.
Ukongeza, xa ukhetha amaso kazibuthe, kuyimfuneko ukuba kuthathelwe ingqalelo ukuguquguquka amaso magnetic, leyo ngokubanzi kufuneka derated ngama-80%, kunye nefuthe DC impedance ukuhla kwamandla ombane kufuneka kuthathelwe ingqalelo xa isetyenziswa kwiisekethe amandla.
Ixesha lokuposa: Jul-24-2023