Ama-capacitor okuhlunga, ama-inductors emodi evamile, kanye nobuhlalu kazibuthe kuyizibalo ezivamile kumasekhethi wokuklama we-EMC, futhi kungamathuluzi amathathu anamandla okuqeda ukuphazamiseka kukazibuthe.
Ngeqhaza lalaba abathathu kusekethe, ngikholwa ukuthi kukhona onjiniyela abaningi abangayiqondi, indatshana evela ekwakhiweni kokuhlaziywa okuningiliziwe komgomo wokuqeda ama-EMC amathathu abukhali kakhulu.
1.I-capacitor yokuhlunga
Nakuba i-resonance ye-capacitor ingathandeki kusukela ekubukeni kokuhlunga umsindo we-high-frequency, i-resonance ye-capacitor ayiyingozi ngaso sonke isikhathi.
Lapho imvamisa yomsindo ozohlungwa inqunywa, umthamo we-capacitor ungalungiswa ukuze iphuzu elizwakalayo livele liwele emazingeni okuphazamisa.
Kubunjiniyela obusebenzayo, imvamisa yomsindo we-electromagnetic okufanele uhlungwe ivamise ukuba phezulu njengamakhulu ama-MHz, noma nangaphezu kuka-1GHz.Ngomsindo onjalo we-electromagnetic ephezulu, kuyadingeka ukusebenzisa i-capacitor ephakathi nendawo ukuze uhlunge ngaphandle ngempumelelo.
Isizathu sokuthi kungani ama-capacitor ajwayelekile engakwazi ukuhlunga ngempumelelo umsindo we-high-frequency kungenxa yezizathu ezimbili:
(1) Isizathu esisodwa siwukuthi i-inductance ye-capacitor lead ibangela i-capacitor resonance, eveza i-impedance enkulu kusignali ye-high-frequency, futhi yenza buthaka umphumela we-bypass wesignali ye-high-frequency;
(2) Esinye isizathu ukuthi i-parasitic capacitance phakathi kwezintambo ezihlanganisa isignali ye-high-frequency, ukunciphisa umphumela wokuhlunga.
Isizathu sokuthi kungani i-capacitor ehamba phambili ingakwazi ukuhlunga ngokuphumelelayo umsindo we-high-frequency ukuthi i-capacitor ngokusebenzisa-core ayinayo inkinga yokuthi i-lead inductance ibangela ukuthi i-capacitor resonance frequency iphansi kakhulu.
Futhi i-capacitor ye-capacitor ingafakwa ngokuqondile kuphaneli yensimbi, isebenzisa iphaneli yensimbi ukuze idlale indima yokuhlukaniswa kwe-high-frequency.Kodwa-ke, uma usebenzisa i-capacitor ephakathi, inkinga okufanele uyinake inkinga yokufaka.
Ubuthakathaka obukhulu be-capacitor ye-capacitor ukwesaba izinga lokushisa eliphezulu nomthelela wokushisa, okudala ubunzima obukhulu lapho kushiselwa i-capacitor nge-core-core panel yensimbi.
Ama-capacitor amaningi awonakele ngesikhathi sokushisela.Ikakhulukazi lapho inani elikhulu lama-capacitor ayisisekelo lidinga ukufakwa kuphaneli, uma nje kukhona umonakalo, kunzima ukulungisa, ngoba lapho i-capacitor eyonakele isusiwe, izodala umonakalo kwamanye ama-capacitor aseduze.
2.Common mode inductance
Njengoba izinkinga ezibhekene ne-EMC ngokuvamile ziwukuphazamiseka kwemodi evamile, ama-inductors emodi evamile nawo angenye yezingxenye zethu ezinamandla ezivame ukusetshenziswa.
I-inductor yemodi evamile iyithuluzi lokucindezela lemodi evamile ene-ferrite njengomongo, ehlanganisa amakhoyili amabili anosayizi ofanayo kanye nenani elifanayo lamajika alimele ngokulinganayo kumongo ofanayo kazibuthe we-ferrite ukuze kwakhe idivayisi eneziphetho ezine, inomphumela omkhulu wokucindezela i-inductance yesiginali yemodi evamile, kanye ne-inductance encane yokuvuza yesiginali yemodi yokuhlukanisa.
Isimiso siwukuthi lapho imodi evamile yamanje igeleza, ukugeleza kazibuthe kuyindandatho kazibuthe idlula omunye komunye, ngaleyo ndlela ibe ne-inductance enkulu, evimbela imodi evamile yamanje, futhi lapho amakhoyili amabili egeleza kumodi yokuhlukanisa yamanje, i-flux kazibuthe. kuyindandatho kazibuthe ikhansela omunye nomunye, futhi cishe akukho inductance, ngakho imodi umehluko wamanje ingadlula ngaphandle attenuation.
Ngakho-ke, i-inductor yemodi evamile ingacindezela ngokuphumelelayo isignali yokuphazamiseka kwemodi evamile emgqeni olinganiselayo, kodwa ayinawo umthelela ekudluliseni okujwayelekile kwesignali yemodi yokuhlukanisa.
Ama-inductors emodi evamile kufanele ahlangabezane nezidingo ezilandelayo lapho ekhiqizwa:
(1) Izintambo ezilimele kunkambo yekhoyili kufanele zivalwe ukuze kuqinisekiswe ukuthi akukho seyikhethi enqamukayo phakathi kokuphenduka kwekhoyili ngaphansi kwesenzo sokugeleza okungaphezu kwamandla;
(2) Uma ikhoyili igeleza kumandla amakhulu asheshayo, ingqikithi kazibuthe akufanele igcwale;
(3) Ingqikithi kazibuthe kukhoyili kufanele ivalwe ikhoyili ukuze kuvinjwe ukuphuka phakathi kwakho kokubili ngaphansi kwesenzo sokugcwala okungaphezu kwamandla;
(4) Ikhoyili kufanele ilinyazwe kungqimba olulodwa ngangokunokwenzeka, ukuze kwehliswe amandla e-parasitic ekhoyili futhi kuthuthukise ikhono lekhoyili lokudlulisa ukuguquguquka kwesikhashana.
Ngaphansi kwezimo ezijwayelekile, ngenkathi sinake ukukhethwa kwebhendi ye-frequency edingekayo ukuze isihlungi, lapho i-impedance yemodi evamile ikhudlwana, iba ngcono, ngakho-ke sidinga ukubheka idatha yedivayisi lapho sikhetha i-inductor yemodi evamile, ikakhulukazi ngokuya I-impedance frequency curve.
Ukwengeza, lapho ukhetha, qaphela umthelela wemodi ehlukile yokuvimbela isignali, ikakhulukazi egxile ekuvimbeleni imodi yokuhlukanisa, ikakhulukazi ukunaka amachweba anesivinini esikhulu.
3.Ubuhlalu obuzibuthe
Emkhiqizweni wesekethe yedijithali yenqubo ye-EMC yokuklama, sivame ukusebenzisa ubuhlalu kazibuthe, impahla ye-ferrite iyingxubevange ye-iron-magnesium noma i-iron-nickel alloy, le nto inokungena okuphakeme kazibuthe, ingaba i-inductor phakathi kokuhamba kwekhoyili uma kwenzeka iphezulu. imvamisa kanye nokumelana okuphezulu okukhiqizwa ubuncane be-capacitance.
Izinto ze-Ferrite zivame ukusetshenziswa kumafrikhwensi aphezulu, ngoba kumafrikhwensi aphansi izici zabo eziyinhloko ze-inductance zenza ukulahlekelwa kulayini kube kuncane kakhulu.Kumafrikhwensi aphezulu, ikakhulukazi izilinganiso zesici sokusabela kanye nokushintsha nobuningi.Ekusetshenzisweni okungokoqobo, izinto ezisetshenziswayo ze-ferrite zisetshenziswa njengezibambisi zefrikhwensi ephezulu kumasekhethi omsakazo.
Eqinisweni, i-ferrite ilingana kangcono nokufana kokumelana ne-inductance, ukumelana kufinyezwa yi-inductor nge-frequency ephansi, futhi i-impedance ye-inductor iba phezulu kakhulu emazingeni aphezulu, ukuze okwamanje konke kudlule ukumelana.
I-Ferrite iyithuluzi elidlayo lapho amandla e-high-frequency eguqulwa abe amandla okushisa, okunqunywa izici zayo zokumelana nogesi.Ubuhlalu kazibuthe be-Ferrite bunezici ezingcono zokuhlunga zemvamisa ephezulu kunama-inductors ajwayelekile.
I-Ferrite iyamelana namafrikhwensi aphezulu, okulingana ne-inductor enesici sekhwalithi ephansi kakhulu, ngakho-ke ingakwazi ukugcina i-impedance ephezulu ebangeni elibanzi lefrikhwensi, ngaleyo ndlela ithuthukise ukusebenza kahle kokuhlunga imvamisa ephezulu.
Ku-low frequency band, i-impedance yakhiwe nge-inductance.Emazingeni aphansi, i-R incane kakhulu, futhi amandla kazibuthe we-core aphezulu, ngakho-ke i-inductance inkulu.I-L idlala indima enkulu, futhi ukuphazamiseka kazibuthe kucindezelwa ukucabangela.Futhi ngalesi sikhathi, ukulahlekelwa komgogodla kazibuthe kuncane, yonke idivayisi ilahlekelwa kancane, izici eziphezulu ze-Q ze-inductor, le inductor kulula ukubangela i-resonance, ngakho-ke ku-band frequency ephansi, ngezinye izikhathi kungase kube nokuphazanyiswa okuthuthukisiwe. ngemva kokusetshenziswa ubuhlalu kazibuthe ferrite.
Ku-high frequency band, i-impedance yakhiwe izingxenye zokumelana.Njengoba imvamisa ikhula, ukufinyeleleka kwe-magnetic core kuncipha, okuholela ekwehleni kwe-inductance ye-inductor kanye nokwehla kwengxenye ye-inductive reactance.
Kodwa-ke, ngalesi sikhathi, ukulahlekelwa kwe-magnetic core kuyanda, ingxenye yokumelana iyanda, okuholela ekwandeni kwe-impedance ephelele, futhi lapho isignali ye-high-frequency idlula ku-ferrite, ukuphazamiseka kwe-electromagnetic kuyamuncwa futhi kuguqulwe ifomu. wokukhipha ukushisa.
Izingxenye zokucindezelwa kwe-Ferrite zisetshenziswa kabanzi kumabhodi wesifunda aphrintiwe, izintambo zamandla kanye nemigqa yedatha.Isibonelo, into yokucindezela i-ferrite yengezwa ekugcineni kokungena kwentambo yamandla yebhodi eliphrintiwe ukuze kuhlungwe ukuphazanyiswa kwe-high-frequency.
Indandatho kazibuthe ye-Ferrite noma ubuhlalu obuzibuthe busetshenziswa ngokukhethekile ukucindezela ukuphazamiseka kwemvamisa ephezulu kanye nokuphazamiseka okuphezulu kwemigqa yesignali nezintambo zamandla, futhi inamandla okumunca ukuphazamiseka kwe-electrostatic discharge pulse.Ukusetshenziswa kobuhlalu obuzibuthe be-chip noma ama-chip inductors kuncike kakhulu ekusebenziseni okungokoqobo.
Ama-chip inductors asetshenziswa kumasekethe azwakalayo.Lapho umsindo we-EMI ongadingekile udinga ukuqedwa, ukusetshenziswa kobuhlalu obuzibuthe be-chip kuyisinqumo esingcono kakhulu.
Ukusetshenziswa kwe-chip yobuhlalu kazibuthe nama-chip inductors
Ama-chip inductors:Ifrikhwensi yomsakazo (i-RF) nokuxhumana okungenantambo, okokusebenza kobuchwepheshe bolwazi, izitholi ze-radar, izinto zikagesi zezimoto, amafoni omakhalekhukhwini, ama-pager, okokusebenza komsindo, abasizi bedijithali bomuntu siqu (ama-PDA), amasistimu okulawula okukude angenantambo, namamojula okunikezwa kwamandla kagesi aphansi.
Chip ubuhlalu kazibuthe:Amasekhethi akhiqiza iwashi, ukuhlunga phakathi kwamasekhethi e-analog nedijithali, okokufaka/okuphumayo kwezixhumi zangaphakathi (ezifana nezimbobo ze-serial, izimbobo ezifanayo, amakhibhodi, amagundane, ezokuxhumana ezikude, amanethiwekhi endawo), amasekhethi e-RF namadivayisi anengqondo atholakala kalula. ukuphazamiseka, ukuhlunga kokuphazanyiswa kwe-high-frequency okwenziwe kumasekhethi okuphakela amandla, amakhompyutha, amaphrinta, amarekhodi evidiyo (VCRS), ukucindezelwa komsindo we-EMI ezinhlelweni zikamabonakude kanye nomakhalekhukhwini.
Iyunithi yobuhlalu obukazibuthe i-ohms, ngenxa yokuthi iyunithi yobuhlalu obuzibuthe yigama ngokuhambisana ne-impedance eyikhiqizayo ngefrikhwensi ethile, futhi iyunithi yokungaphumeleli nayo i-ohms.
I-DATASHEET yobuhlalu obuzibuthe ngokuvamile izohlinzeka ngefrikhwensi nezici zokuthikamezeka zejika, ngokuvamile elingu-100MHz njengezinga elijwayelekile, isibonelo, uma imvamisa engu-100MHz lapho ukuvimbeka kobuhlalu obuzibuthe bulingana no-1000 ohms.
Ngebhendi yefrikhwensi esifuna ukuyihlunga, sidinga ukukhetha okukhudlwana okubambezelekayo kobuhlalu obuzibuthe, okungcono, ngokuvamile sikhethe ukuthintana okungu-600 ohm noma ngaphezulu.
Ngaphezu kwalokho, lapho ukhetha ubuhlalu obukazibuthe, kuyadingeka ukuthi unake ukugeleza kobuhlalu obuzibuthe, ngokuvamile obudinga ukwehliswa ngo-80%, kanye nomthelela we-DC impedance ekwehleni kwe-voltage kufanele kucatshangelwe lapho kusetshenziswa kumasekhethi kagesi.
Isikhathi sokuthumela: Jul-24-2023