Txawm hais tias hom hom chokes yog nrov, lwm txoj hauv kev yuav yog lub lim dej monolithic EMI.Thaum muab tso kom zoo, cov khoom siv ntau yam ceramics muab cov suab nrov nrov nrov.
Ntau yam ua rau muaj qhov "suab nrov" cuam tshuam uas tuaj yeem ua rau puas tsuaj lossis cuam tshuam rau kev ua haujlwm ntawm cov khoom siv hluav taws xob.Hnub no lub tsheb yog qhov piv txwv zoo. Hauv lub tsheb, koj yuav pom Wi-Fi, Bluetooth, xov tooj cua satellite, GPS systems, thiab Qhov ntawd yog qhov pib xwb.Txawm li cas los tswj cov suab nrov no cuam tshuam, kev lag luam feem ntau siv cov ntaub thaiv npog thiab EMI lim kom tshem tawm cov suab nrov tsis xav tau.Tab sis qee qhov kev daws teeb meem los tshem tawm EMI / RFI tsis txaus.
Qhov teeb meem no ua rau ntau OEMs kom tsis txhob siv 2-capacitor sib txawv, 3-capacitor (ib qho X capacitor thiab 2 Y capacitors), feedthrough filters, hom chokes, los yog kev sib xyaw ua ke ntawm cov no rau cov kev daws teeb meem zoo dua xws li monolithic EMI lim nrog. zoo dua lub suab tsis lees paub hauv ib pob me me.
Thaum cov khoom siv hluav taws xob tau txais cov khoom siv hluav taws xob muaj zog, cov khoom siv hluav taws xob tsis xav tau tuaj yeem cuam tshuam rau hauv Circuit Court thiab ua rau tsis ua haujlwm - lossis cuam tshuam rau kev ua haujlwm.
EMI/RFI tuaj yeem ua tau raws li kev ua los yog hluav taws xob emissions.Thaum EMI ua, nws txhais tau hais tias lub suab nrov mus raws cov hluav taws xob conductors.Radiated EMI tshwm sim thaum lub suab nrov mus los ntawm huab cua nyob rau hauv daim ntawv ntawm magnetic teb los yog xov tooj cua tsis.
Txawm hais tias lub zog siv los ntawm sab nraud me me, yog tias nws sib xyaw nrog cov xov tooj cua tsis siv rau kev tshaj tawm thiab kev sib txuas lus, nws tuaj yeem ua rau poob ntawm kev txais tos, lub suab tsis zoo hauv lub suab, lossis cuam tshuam ntawm video.Yog tias lub zog muaj zog heev, nws tuaj yeem ua tau puas khoom siv hluav taws xob.
Cov chaw muaj xws li lub suab nrov (piv txwv li, hluav taws xob hluav taws xob, teeb pom kev zoo, thiab lwm yam) thiab cov suab nrov ntawm tib neeg (xws li, kev sib cuag suab nrov, cov khoom siv xau siv cov khoom siv siab, tsis xav tau emissions, thiab lwm yam). Feem ntau, EMI / RFI suab nrov yog hom suab nrov. , yog li qhov kev daws teeb meem yog siv lub lim EMI kom tshem tawm cov tsis xav tau ntau zaus, xws li cov khoom sib cais lossis kos rau hauv lub rooj tsav xwm hauv Circuit Court.
EMI Filters EMI cov ntxaij lim dej feem ntau muaj cov khoom siv passive, xws li cov khoom siv hluav taws xob thiab cov inductors, uas txuas nrog rau kev tsim hluav taws xob.
"Inductors tso cai rau DC lossis tsawg zaus tam sim no dhau los thaum thaiv cov tsis xav tau, tsis xav tau cov hluav taws xob ntau zaus.Capacitors muab txoj hauv kev uas tsis muaj impedance los hloov cov suab nrov nrov ntawm lub tshuab lim tawm mus rau lub zog lossis kev sib txuas hauv av, "Manufactures a Multilayer Ceramic said Christophe Cambrelin ntawm capacitor tuam txhab Johanson Dielectrics.EMI lim.
Cov txheej txheem kev lim dej ib txwm muaj xws li cov lim dej qis uas siv cov capacitors uas dhau cov teeb liab nrog cov zaus hauv qab qhov kev xaiv txiav tawm zaus thiab txo qis cov teeb liab nrog cov zaus siab tshaj qhov txiav tawm zaus.
Ib qho kev pib pib yog siv ob lub capacitors nyob rau hauv ib qho kev teeb tsa sib txawv, nrog rau ib lub capacitor ntawm txhua kab ntawm qhov sib txawv ntawm qhov sib txawv thiab hauv av.Capacitive cov ntxaij lim dej hauv txhua ceg hloov EMI / RFI mus rau hauv av saum toj kawg nkaus qhov kev txiav tawm ntau zaus.Vim tias qhov kev teeb tsa no suav nrog xa cov teeb liab ntawm cov theem sib txawv ntawm ob lub xov hlau, lub teeb liab-rau-suab nrov piv tau zoo dua thaum lub suab tsis xav tau xa mus rau hauv av.
"Hmoov tsis zoo, tus nqi capacitance ntawm MLCCs nrog X7R dielectrics (feem ntau yog siv rau qhov kev ua haujlwm no) tuaj yeem sib txawv nrog lub sijhawm, kev tsis sib haum xeeb thiab qhov kub thiab txias," Cambrelin hais.
"Yog li txawm tias ob lub capacitors zoo sib xws ntawm ib lub sijhawm ntawm chav tsev kub ntawm qhov tsis tshua muaj hluav taws xob, lawv yuav xaus nrog cov txiaj ntsig sib txawv heev ib zaug, voltage lossis kub hloov.Qhov kev tsis sib haum xeeb ntawm ob lub xov hlau yuav ua rau cov lus teb tsis sib xws nyob ze ntawm lub lim lim.Yog li ntawd, nws hloov cov suab nrov nrov rau cov suab nrov sib txawv. "
Lwm qhov kev daws teeb meem yog txhawm rau txuas tus nqi loj "X" capacitor ntawm ob "Y" capacitors.Qhov "X" capacitive shunt muab qhov zoo tagnrho-hom kev tshuav nyiaj li cas, tab sis kuj muaj qhov tsis zoo ntawm cov teeb liab sib txawv filtering.Tej zaum qhov kev daws teeb meem feem ntau. thiab lwm txoj hauv kev lim dej tsawg dhau yog hom choke.
Ib hom hom choke yog 1: 1 transformer nrog ob qho tib si windings ua thawj thiab theem nrab.Nyob rau hauv txoj kev no, lub tam sim no los ntawm ib winding induces ib tug opposite tam sim no nyob rau hauv lub winding.Hmoov tsis zoo, hom hom chokes kuj hnyav, kim, thiab raug. rau kev vibration-induced tsis ua hauj lwm.
Txawm li cas los xij, qhov tsim nyog hom choke nrog kev sib txuam zoo meej thiab sib txuas ntawm cov windings yog pob tshab rau cov teeb liab sib txawv thiab muaj kev cuam tshuam siab rau hom suab nrov.Ib qho tsis zoo ntawm hom chokes yog qhov tsawg zaus ntau yam vim muaj kab mob parasitic.Rau cov khoom siv tseem ceeb. , qhov siab dua qhov inductance siv kom tau txais kev lim dej tsawg, yuav tsum tau hloov ntau dua, yog li ua rau cov kab mob parasitic capacitance tsis tuaj yeem dhau qhov kev lim dej siab.
Kev tsis sib haum xeeb ntawm cov windings vim yog kev tsim kho tshuab ua rau kev hloov pauv hloov, qhov twg ib feem ntawm lub teeb liab lub zog hloov mus rau hom suab nrov thiab vice versa.Qhov teeb meem no tuaj yeem ua rau electromagnetic compatibility thiab tiv thaiv teeb meem.Qhov kev tsis sib haum xeeb kuj txo cov inductance zoo ntawm txhua ceg.
Nyob rau hauv txhua rooj plaub, hom hom chokes muaj qhov zoo dua lwm yam kev xaiv thaum lub teeb liab sib txawv (dhau los ntawm) ua haujlwm nyob rau hauv tib zaus ntau npaum li cov suab nrov hom uas yuav tsum tau tsis lees paub.Siv ib hom hom choke, lub teeb liab passband tuaj yeem txuas ntxiv. mus rau hom kev tsis lees paub band.
Monolithic EMI Filters Txawm hais tias hom chokes yog nrov, monolithic EMI cov ntxaij lim dej kuj siv tau.Thaum muab tso rau kom zoo, cov khoom siv ntau yam ceramics muab cov suab nrov nrov zoo sib xws.Lawv muab ob qho sib npaug shunt capacitors hauv ib pob rau kev sib nrig inductance tshem tawm thiab tiv thaiv. .Cov lim dej no siv ob txoj kev sib cais hluav taws xob hauv ib qho khoom siv txuas nrog plaub qhov kev sib txuas sab nraud.
Txhawm rau kom tsis txhob muaj kev ntxhov siab, nws yuav tsum raug sau tseg tias cov lim dej monolithic EMI tsis yog ib txwm siv los ntawm cov khoom siv hluav taws xob.Txawm hais tias lawv zoo tib yam ( tib lub ntim thiab cov tsos), lawv txawv heev hauv kev tsim, thiab lawv tsis txuas nrog tib txoj kev.Zoo li lwm yam EMI cov ntxaij lim dej, monolithic EMI lim attenuate tag nrho cov zog saum toj no qhov kev txiav tawm zaus thiab xaiv kom dhau tsuas yog lub teeb liab xav tau lub zog, thaum hloov lub suab tsis xav tau rau "hauv av".
Txawm li cas los xij, tus yuam sij yog qhov tsis tshua muaj inductance thiab txuam impedance.Rau monolithic EMI cov ntxaij lim dej, cov terminals yog txuas nrog rau ib qho kev siv (shield) electrode nyob rau hauv lub cuab yeej, thiab cov phaj yog sib cais los ntawm kev siv electrode.Electrostatically, peb cov hluav taws xob nodes. yog tsim los ntawm ob lub capacitive halves uas sib koom ib qho kev siv electrode, tag nrho muaj nyob rau hauv ib lub cev ceramic.
Qhov sib npaug ntawm ob feem ntawm lub capacitor kuj txhais tau hais tias cov teebmeem piezoelectric sib npaug thiab sib npaug, tshem tawm ib leeg tawm.Qhov kev sib raug zoo no kuj cuam tshuam rau qhov kub thiab qhov hluav taws xob sib txawv, yog li cov khoom ntawm ob kab hnub nyoog sib npaug.Yog tias muaj ib qho downside rau cov monolithic EMI. Cov ntxaij lim dej, nws yog qhov uas lawv yuav tsis ua haujlwm yog tias lub suab nrov hom sib txawv nyob ntawm tib zaus raws li lub teeb liab sib txawv. "Hauv qhov no, hom choke hom yog ib qho kev daws teeb meem zoo dua," Cambrelin hais.
Xauj cov teeb meem tshiab kawg ntawm Tsim Ntiaj Teb thiab cov teeb meem rov qab rau hauv ib qho yooj yim-rau-siv, zoo hom. Kho kom raug, sib qhia thiab rub tawm hnub no nrog cov thawj coj tsim engineering magazine.
Lub ntiaj teb cov teeb meem daws teeb meem EE lub rooj sab laj npog microcontrollers, DSP, kev sib txuas lus, analog thiab digital tsim, RF, hluav taws xob hluav taws xob, PCB routing, thiab lwm yam
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Post lub sij hawm: Apr-19-2022
