Yuav ua li cas sai sai nrhiav qhov teeb meem ntawm kev hloov hluav taws xob?
inductor
Hloov cov khoom siv hluav taws xob siv qis EMI inductors nrog kaw ferrite cores. Xws li puag ncig lossis kaw E-cores. Qhib cores kuj tseem siv tau yog tias lawv muaj cov yam ntxwv EMI qis dua thiab khaws cia kom deb ntawm cov xaim hluav taws xob tsawg thiab cov khoom siv. Yog tias siv cov tub ntxhais qhib, nws kuj yog ib lub tswv yim zoo kom muaj cov ncej ntawm cov tub ntxhais perpendicular rau PCB. Qws cores feem ntau yog siv los tshem tawm feem ntau ntawm cov suab nrov tsis xav tau.
Tawm tswv yim
Sim khaws cov lus tawm tswv yim kom deb ntawm inductors thiab suab nrov. Kuj ua kom cov lus tawm tswv yim ncaj li ua tau thiab tuab dua. Qee zaum muaj kev sib pauv ntawm ob txoj hauv kev no, tab sis khaws cov lus tawm tswv yim kom deb ntawm inductor's EMI thiab lwm qhov chaw nrov nrov yog qhov tseem ceeb tshaj ntawm ob. Muab cov lus tawm tswv yim rau sab nraud ntawm tus inductor ntawm PCB thiab cais nws nrog lub dav hlau hauv nruab nrab.
lim capacitor
Thaum siv lub me me ceramic input lim capacitor, nws yuav tsum muab tso rau ze li sai tau rau VIN tus pin ntawm IC. Qhov no yuav tshem tawm ntau npaum li cas ntawm cov txiaj ntsig ntawm kab inductance ntau npaum li qhov ua tau, muab cov kab IC sab hauv ib qhov chaw nqus hluav taws xob. Qee qhov kev tsim ntawm cov khoom siv hluav taws xob hloov pauv yuav tsum tau siv cov khoom siv pub-rau pem hauv ntej capacitor txuas los ntawm cov zis mus rau tus pin tawm tswv yim, feem ntau yog vim li cas kev ruaj ntseg. Hauv qhov no, nws tseem yuav tsum nyob ze li sai tau rau IC. Siv cov mounting capacitors kuj txo cov hlau lead ntev, uas txo cov suab nrov coupling rau hauv lub kav hlau txais xov zoo vim yog cov khoom ntawm lub qhov.
nyiaj pab
Yog tias tsim nyog ntxiv cov nyiaj them rau sab nraud rau kev ruaj ntseg, lawv yuav tsum tau nyob ze li sai tau rau IC. Surface-mount Cheebtsam kuj tau pom zoo ntawm no rau tib yam laj thawj uas tau tham txog cov lim capacitors. Cov khoom no yuav tsum tsis txhob nyob ze rau qhov inductor.
cov kab thiab hauv av dav hlau
Khaws tag nrho cov hwj chim (high tam sim no) cov cim luv luv, ncaj, thiab tuab li sai tau. Ntawm tus qauv PCB, nws yog qhov zoo tshaj kom muaj qhov dav tsawg kawg nkaus ntawm 15mil (0.381mm) ib amp. Lub inductor, tso zis capacitor, thiab cov zis diode yuav tsum nyob sib ze li sai tau. Qhov no tuaj yeem pab txo qis EMI tshwm sim los ntawm kev hloov cov khoom siv hluav taws xob thaum cov hloov pauv loj ntws los ntawm lawv. Qhov no kuj txo cov hlau lead inductance thiab kuj, uas txo cov suab nrov spikes, ringing thiab resistive poob, uas tuaj yeem tsim qhov yuam kev voltage. Lub IC hauv av, input capacitor, output capacitor, thiab output diode (yog tias tam sim no) yuav tsum tau txuas ncaj qha mus rau ib lub dav hlau hauv av. Nws yog qhov zoo tshaj kom muaj lub dav hlau hauv av ntawm ob sab ntawm PCB. Qhov no txo cov voj voog hauv av thiab nqus ntau EMI tsim los ntawm inductor, yog li txo cov suab nrov. Rau multilayer boards nrog ntau tshaj ob txheej, lub dav hlau hauv av tuaj yeem siv los cais lub dav hlau fais fab (qhov chaw uas lub zog muaj zog thiab cov khoom siv nyob) thiab lub dav hlau teeb liab (qhov chaw uas cov lus tawm tswv yim thiab cov nyiaj them poob haujlwm nyob) los txhim kho kev ua haujlwm. Ntawm multilayer boards, vias yuav tsum tau txuas cov kab mus rau cov dav hlau sib txawv. Yog hais tias tus kab mob yuav tsum nqa ib tug loj tam sim no los ntawm ib sab mus rau lwm yam, nws yog ib qho zoo xyaum siv ib tug qauv ntawm ib tug 200mA ntawm tam sim no.
Teem lub Cheebtsam kom cov thawj tam sim no loops tig nyob rau hauv tib txoj kev. Muaj ob lub zog lub xeev nyob ntawm seb lub taub hau regulator ua haujlwm li cas. Ib lub xeev yog thaum qhib qhib thiab lwm lub xeev yog thaum qhib qhib. Thaum lub sij hawm txhua lub xeev, ib lub voj tam sim no yog tsim los ntawm cov khoom siv fais fab uas tam sim no nyob rau. Cov khoom siv hluav taws xob tau npaj kom lub voj voog tam sim no coj mus rau tib qho kev taw qhia thaum txhua lub xeev. Qhov no tiv thaiv magnetic reversals nyob rau hauv cov kab ntawm ob ib nrab-ntiv nplhaib thiab txo EMI emissions.
cua txias
Thaum siv lub tshuab hluav taws xob ICs lossis cov hluav taws xob sab nraud, PCB feem ntau siv tau los ua lub dab dej kub. Qhov no yog siv tooj liab clad nto ntawm PCB los pab lub cuab yeej dissipate tshav kub. Xa mus rau phau ntawv qhia tshwj xeeb rau kev siv PCB thermal dissipation. Qhov no feem ntau tuaj yeem txuag lub tshuab cua txias ntxiv los ntawm kev hloov hluav taws xob.
