nkhani

Ma capacitor ndi amodzi mwazinthu zomwe zimagwiritsidwa ntchito kwambiri pama board ozungulira. Pomwe kuchuluka kwa zida zamagetsi (kuchokera ku mafoni am'manja kupita kumagalimoto) kukukulirakulira, momwemonso kufunikira kwa ma capacitor. ku zigawo zongokhala, ndipo ma capacitor akhala akusowa1.
Zokambirana pamutu wa ma capacitors zimatha kusinthidwa mosavuta kukhala bukhu kapena dikishonale.Choyamba, pali mitundu yosiyanasiyana ya ma capacitors, monga electrolytic capacitors, film capacitors, ceramic capacitors ndi zina zotero.Kenako, mumtundu womwewo, pali zosiyana. zipangizo za dielectric.Palinso magulu osiyanasiyana.Kukhudzana ndi mawonekedwe a thupi, pali mitundu iwiri ya materminal ndi atatu-terminal capacitor.Palinso mtundu wa X2Y capacitor, womwe kwenikweni ndi awiri a Y capacitors omwe amaikidwa m'modzi.Nanga bwanji za supercapacitors ?Chowonadi ndichakuti, ngati mutakhala pansi ndikuyamba kuwerenga maupangiri osankha ma capacitor kuchokera kwa opanga akuluakulu, mutha kutha tsikulo mosavuta!
Popeza nkhaniyi ikukhudzana ndi zofunikira, ndigwiritsa ntchito njira yosiyana monga mwachizolowezi.Monga tafotokozera kale, malangizo osankhidwa a capacitor angapezeke mosavuta pa mawebusaiti ogulitsa 3 ndi 4, ndipo akatswiri a m'munda amatha kuyankha mafunso ambiri okhudza capacitors.M'nkhaniyi, Sindidzabwereza zomwe mungapeze pa intaneti, koma ndikuwonetsa momwe mungasankhire ndikugwiritsa ntchito ma capacitors kudzera mu zitsanzo zothandiza.Zina zosadziwika bwino za kusankha capacitor, monga kuwonongeka kwa capacitance, zidzafotokozedwanso.Mutawerenga nkhaniyi, inu Muyenera kumvetsetsa bwino kugwiritsa ntchito ma capacitors.
Zaka zapitazo, pamene ndinkagwira ntchito ku kampani yopanga zipangizo zamagetsi, tinali ndi funso lofunsana ndi injiniya wamagetsi amagetsi. capacitor?" ndi "Kodi ntchito ya ceramic capacitor pafupi ndi chip ndi chiyani?" Tikukhulupirira kuti yankho lolondola ndi DC bus capacitor Yogwiritsidwa ntchito posungira mphamvu, ma capacitor a ceramic amagwiritsidwa ntchito posefa.
Yankho "lolondola" lomwe timafuna limasonyeza kuti aliyense pa gulu lojambula amayang'ana ma capacitors kuchokera kumayendedwe osavuta a dera, osati kuchokera kumunda wamaganizo.Zowona za chiphunzitso cha dera sizolakwika.Pafupipafupi (kuchokera ku kHz pang'ono). mpaka MHz ochepa), chiphunzitso cha dera nthawi zambiri chimatha kufotokozera vutoli bwino.Izi ndi chifukwa chakuti maulendo apansi, chizindikirocho chimakhala chosiyana kwambiri. Pogwiritsa ntchito chiphunzitso cha dera, tikhoza kuona capacitor yomwe ikuwonetsedwa mu Chithunzi 1, pamene kukana kwa mndandanda wofanana ( ESR) ndi equivalent series inductance (ESL) imapangitsa kusokoneza kwa capacitor kusintha pafupipafupi.
Chitsanzochi chikufotokozera momveka bwino kayendetsedwe ka kayendetsedwe ka kayendetsedwe ka kayendetsedwe ka kayendetsedwe ka kayendetsedwe ka kayendetsedwe ka kayendetsedwe ka kayendetsedwe ka kayendetsedwe ka kayendetsedwe ka kayendetsedwe ka kayendetsedwe ka kayendedwe ka kayendetsedwe ka kayendetsedwe ka kayendetsedwe ka kayendetsedwe ka kayendetsedwe ka kayendetsedwe ka kayendetsedwe ka kayendetsedwe ka kayendetsedwe ka kayendetsedwe ka kayendetsedwe ka kayendetsedwe ka kayendetsedwe ka kayendetsedwe ka kayendetsedwe ka kayendetsedwe ka kayendetsedwe ka kayendetsedwe ka kayendetsedwe ka kayendetsedwe ka kayendetsedwe ka kayendetsedwe ka kayendetsedwe ka kayendetsedwe ka kayendetsedwe ka kayendetsedwe ka kayendetsedwe ka kayendetsedwe kake. ili ndi malire ake.
Lero, ngati nditafunsidwa funso lomwelo la kuyankhulana, ndikanavala magalasi owonetsetsa za chiphunzitso cha munda ndikunena kuti mitundu yonse ya capacitor ndi zipangizo zosungiramo mphamvu.Kusiyana kwake ndikuti ma electrolytic capacitors amatha kusunga mphamvu zambiri kuposa ma capacitors a ceramic.Koma ponena za kufalitsa mphamvu , Ceramic capacitors amatha kutumiza mphamvu mofulumira.Izi zikufotokozera chifukwa chake ma capacitors a ceramic ayenera kuikidwa pafupi ndi chip, chifukwa chip chimakhala ndi maulendo apamwamba osinthasintha ndi kusinthasintha mofulumira poyerekeza ndi dera lalikulu la mphamvu.
Kuchokera pamalingaliro awa, tikhoza kufotokozera mwachidule miyeso iwiri yogwiritsira ntchito capacitor.Chimodzi ndi kuchuluka kwa mphamvu zomwe capacitor ikhoza kusunga, ndipo ina ndi momwe mphamvuyi ingasinthire mofulumira.Zonsezi zimadalira njira yopangira capacitor, dielectric material, kugwirizana ndi capacitor, ndi zina zotero.
Pamene kusinthana kwa dera kumatsekedwa (onani Chithunzi 2), kumasonyeza kuti katunduyo amafunikira mphamvu kuchokera ku gwero la mphamvu.Kuthamanga kumene kusinthaku kumatseka kumatsimikizira kufunika kwa mphamvu.Popeza mphamvu imayenda pa liwiro la kuwala (theka). liwiro la kuwala mu zipangizo FR4), zimatenga nthawi kusamutsa mphamvu.Kuonjezera apo, pali impedance mismatch pakati pa gwero ndi kufala mzere ndi katundu. maulendo ozungulira5, chifukwa chake pamene kusinthako kumasintha mofulumira, timawona kuchedwa ndi kulira mu mawonekedwe osinthika.
Chithunzi 2: Zimatengera nthawi kuti mphamvu zichulukane mumlengalenga; kusagwirizana kwa impedance kumayambitsa maulendo angapo ozungulira potengera mphamvu.
Mfundo yakuti kutengera mphamvu kumatenga nthawi ndi maulendo angapo ozungulira amatiuza kuti tifunika kupeza gwero la mphamvu pafupi ndi katundu momwe tingathere, ndipo tiyenera kupeza njira yotumizira mphamvu mwamsanga.Choyamba nthawi zambiri chimatheka ndi kuchepetsa thupi. mtunda pakati pa katundu, kusinthana ndi capacitor.Zotsatirazi zimapindula mwa kusonkhanitsa gulu la ma capacitors ndi impedance yaying'ono kwambiri.
Chiphunzitso cha munda chimafotokozeranso zomwe zimayambitsa phokoso lamtundu wamba.Mwachidule, phokoso lodziwika bwino limapangidwa pamene mphamvu ya katunduyo siidakwaniritsidwe panthawi ya kusintha.Choncho, mphamvu yosungidwa mu danga pakati pa katundu ndi oyendetsa pafupi adzaperekedwa kuti athandizire. kufunikira kwa sitepe.Mpata pakati pa katundu ndi oyendetsa pafupi ndi omwe timatcha parasitic / mutual capacitance (onani Chithunzi 2).
Timagwiritsa ntchito zitsanzo zotsatirazi kuti tisonyeze momwe tingagwiritsire ntchito ma electrolytic capacitors, multilayer ceramic capacitors (MLCC), ndi mafilimu capacitors.Magawo onse ndi chiphunzitso chamunda chimagwiritsidwa ntchito kufotokoza momwe ma capacitors osankhidwa akuyendera.
Electrolytic capacitors amagwiritsidwa ntchito makamaka mu ulalo wa DC ngati gwero lalikulu lamphamvu.Kusankha kwa electrolytic capacitor nthawi zambiri kumadalira:
Pa ntchito ya EMC, makhalidwe ofunika kwambiri a capacitors ndi impedance ndi maonekedwe afupipafupi.Kutulutsa kochepa komwe kumachitidwa nthawi zonse kumadalira ntchito ya DC link capacitor.
Kutsekeka kwa ulalo wa DC sikungodalira ESR ndi ESL ya capacitor, komanso kudera la loop yotentha, monga momwe tawonetsera pa Chithunzi 3. Malo okulirapo otentha amatanthauza kuti kutumiza mphamvu kumatenga nthawi yayitali, kotero magwiridwe antchito zidzakhudzidwa.
Chosinthira chotsikirapo cha DC-DC chinamangidwa kuti chitsimikizire izi.Kukhazikitsa kwa mayeso a EMC asanayambe kutsatiridwa komwe kukuwonetsedwa pa Chithunzi 4 kumapanga sikani yotulutsa mpweya pakati pa 150kHz ndi 108MHz.
Ndikofunika kuonetsetsa kuti ma capacitors omwe amagwiritsidwa ntchito mu phunziro ili onse amachokera kwa wopanga yemweyo kuti apewe kusiyana kwa makhalidwe olepheretsa. capacitor.Chithunzi 5 chikuwonetsa masinthidwe atatu.
Zotsatira zomwe zachitika pamasinthidwe atatuwa zikuwonetsedwa mu Chithunzi 6. Zitha kuwoneka kuti, poyerekeza ndi capacitor imodzi ya 680 µF, ma capacitor awiri a 330 µF amakwanitsa kuchepetsa phokoso la 6 dB pamlingo wokulirapo.
Kuchokera ku chiphunzitso cha dera, tinganene kuti mwa kugwirizanitsa ma capacitors awiri mofanana, ESL ndi ESR zili ndi theka. , mothandiza kuchepetsa nthawi yonse yotumizira mphamvu. kusinthana, timachepetsa nthawi yotengera mphamvu, zomwe zimawonjezera kuyankha kwa capacitor.
Chotsatiracho chimatiuza phunziro lofunika kwambiri.Kuwonjezera mphamvu ya capacitor imodzi sikungagwirizane ndi kufunikira kwa sitepe yowonjezera mphamvu.Ngati n'kotheka, gwiritsani ntchito zigawo zing'onozing'ono za capacitive.Pali zifukwa zambiri zabwino za izi.Choyamba ndi mtengo.Kawirikawiri kuyankhula, chifukwa cha kukula kwa phukusi, mtengo wa capacitor ukuwonjezeka kwambiri ndi mtengo wa capacitance.Kugwiritsira ntchito capacitor imodzi kungakhale kokwera mtengo kuposa kugwiritsa ntchito ma capacitors angapo ang'onoang'ono.Chifukwa chachiwiri ndi kukula.Cholepheretsa pakupanga mankhwala nthawi zambiri chimakhala kutalika kwake. za zigawozo.Kwa ma capacitor akuluakulu, kutalika kwake nthawi zambiri kumakhala kwakukulu kwambiri pakupanga mankhwala.Chifukwa chachitatu ndi ntchito ya EMC yomwe tawona mu phunziroli.
Chinthu chinanso choyenera kuganizira mukamagwiritsa ntchito electrolytic capacitor ndikuti mukalumikiza ma capacitor awiri pamndandanda kuti mugawane voteji, mudzafunika choletsa chowongolera 6.
Monga tanenera kale, ma capacitors a ceramic ndi zipangizo zazing'ono zomwe zingapereke mphamvu mwamsanga.Nthawi zambiri ndimafunsidwa funso lakuti "Kodi ndikufunikira ndalama zingati?" Yankho la funsoli ndiloti kwa ma capacitors a ceramic, mtengo wa capacitance suyenera kukhala wofunika kwambiri. Mfundo yofunika kwambiri pano ndiyo kudziwa kuti ndi nthawi yanji yomwe liwiro la kutumizira mphamvu liri lokwanira pa ntchito yanu.Ngati kutulutsa kochitidwa kulephera pa 100 MHz, ndiye capacitor yokhala ndi cholepheretsa chaching'ono kwambiri pa 100 MHz chidzakhala chisankho chabwino.
Uku ndikusamvetsetsana kwina kwa MLCC. Ndawona mainjiniya akuwononga mphamvu zambiri posankha ma capacitor a ceramic okhala ndi ESR yotsika kwambiri ndi ESL asanalumikize ma capacitor ku RF reference point kudzera m'mizere yayitali. Ndikoyenera kutchula kuti ESL ya MLCC nthawi zambiri imakhala otsika kuposa kugwirizana inductance pa bolodi.Connection inductance akadali chizindikiro chofunika kwambiri chokhudza mkulu pafupipafupi impedance ya ceramic capacitors7.
Chithunzi cha 7 chikuwonetsa chitsanzo choipa. Kufufuza kwautali (0.5 mainchesi kutalika) kumayambitsa osachepera 10nH inductance. Zotsatira zofananitsa zimasonyeza kuti kusokoneza kwa capacitor kumakhala kwakukulu kwambiri kuposa kuyembekezera pafupipafupi (50 MHz).
Limodzi mwavuto la MLCCs ndiloti limakonda kugwirizana ndi kachitidwe ka inductive pa bolodi.Izi zikhoza kuwoneka mu chitsanzo chomwe chili pa Chithunzi 8, pamene kugwiritsa ntchito 10 µF MLCC kumayambitsa resonance pafupifupi 300 kHz.
Mukhoza kuchepetsa resonance posankha chigawo ndi ESR yaikulu kapena kungoyika mtengo wochepa (monga 1 ohm) mndandanda ndi capacitor.Njira yamtunduwu imagwiritsa ntchito zigawo zotayika kuti zithetsere dongosolo.Njira ina ndiyo kugwiritsa ntchito mphamvu ina. kufunika kusuntha phokoso kumalo otsika kapena apamwamba.
Ma capacitor amakanema amagwiritsidwa ntchito m'mapulogalamu ambiri.Iwo ndi ma capacitor omwe amasankha otembenuza amphamvu kwambiri a DC-DC ndipo amagwiritsidwa ntchito ngati zosefera za EMI kupyola mizere yamagetsi (AC ndi DC) ndi masinthidwe osefera wamba.Timatenga X capacitor ngati chitsanzo chosonyeza mfundo zazikuluzikulu zogwiritsira ntchito ma capacitor a filimu.
Ngati chiwombankhanga chichitika, chimathandizira kuchepetsa kupanikizika kwapamwamba kwambiri pamzere, choncho nthawi zambiri amagwiritsidwa ntchito ndi transient voltage suppressor (TVS) kapena metal oxide varistor (MOV).
Mwinamwake mukudziwa kale zonsezi, koma kodi mumadziwa kuti mphamvu ya capacitance ya X capacitor ikhoza kuchepetsedwa kwambiri ndi zaka zogwiritsidwa ntchito? Izi ndi zoona makamaka ngati capacitor ikugwiritsidwa ntchito m'malo a chinyezi.Ndawona mtengo wa capacitance wa X capacitor imangotsika pang'ono peresenti ya mtengo wake wovomerezeka mkati mwa chaka chimodzi kapena ziwiri, kotero dongosolo lomwe poyamba linapangidwa ndi X capacitor linataya chitetezo chonse chomwe capacitor yakutsogolo angakhale nayo.
Ndiye, nchiyani chinachitika? Mpweya wonyezimira ukhoza kutayikira mu capacitor, mmwamba waya ndi pakati pa bokosi ndi epoxy potting compound.The aluminiyamu metallization akhoza kukhala oxidized.Alumina ndi wabwino magetsi insulator, potero kuchepetsa capacitance.Ili ndi vuto kuti onse opanga mafilimu adzakumana.Nkhani yomwe ndikukambayi ndi makulidwe a filimu.Makampani odziwika bwino a capacitor amagwiritsa ntchito mafilimu okhuthala, zomwe zimapangitsa ma capacitor akuluakulu kuposa mitundu ina.Filimu yopyapyala imapangitsa capacitor kukhala yocheperako kuti ichulukitse (voltage, current, kapena kutentha), ndipo nkokayikitsa kudzichiritsa yokha.
Ngati X capacitor sichikugwirizanitsidwa kwamuyaya ndi magetsi, ndiye kuti simukusowa kudandaula.Mwachitsanzo, kwa mankhwala omwe ali ndi chosinthira cholimba pakati pa magetsi ndi capacitor, kukula kungakhale kofunika kwambiri kuposa moyo, ndipo ndiye mukhoza kusankha capacitor woonda.
Komabe, ngati capacitor ikugwirizana kwamuyaya ndi gwero la mphamvu, iyenera kukhala yodalirika kwambiri.The oxidation of capacitors sichingalephereke.Ngati capacitor epoxy material ndi yabwino ndipo capacitor sichidziwika nthawi zambiri kutentha kwambiri, kutsika kwapakati. mtengo uyenera kukhala wocheperako.
M'nkhaniyi, poyamba adayambitsa maganizo a munda wa capacitors.Zitsanzo zothandiza ndi zotsatira zofananitsa zimasonyeza momwe mungasankhire ndikugwiritsa ntchito mitundu yambiri ya capacitor.Tikuyembekeza kuti chidziwitsochi chingakuthandizeni kumvetsa udindo wa capacitors mumagetsi ndi EMC kupanga momveka bwino.
Dr. Min Zhang ndi amene anayambitsa komanso mlangizi wamkulu wa EMC wa Mach One Design Ltd, kampani ya engineering ya ku UK yomwe imagwira ntchito pa EMC consulting, kuthetsa mavuto ndi kuphunzitsa. makampani padziko lonse lapansi.
Mu Compliance ndiye gwero lalikulu la nkhani, zambiri, maphunziro ndi kudzoza kwa akatswiri opanga zamagetsi ndi zamagetsi.
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