EMI tiv thaiv kev hloov hluav taws xob rau ntau zaus bands
Aug 10, 2018| Hauv kev tsim ntawm kev hloov hluav taws xob, EMI yog qhov tseem ceeb heev. Ntau tus neeg tsim khoom tawm tsam nrog qhov teeb meem ntawm kev cuam tshuam electromagnetic thiaj li ua tiav qhov kev xeem. Txawm li cas los xij, EMI hauv Circuit Court yog qhov nyuaj heev, thiab qhov zaus ntawm kev cuam tshuam tsis zoo ib yam. Qee qhov kev cuam tshuam qis dua tsuas yog qee qhov kev hloov kho me me xwb, thaum qee qhov loj dua yuav tsum muaj ntau txoj hauv kev. Hauv daim ntawv no, EMI kev txwv txoj kev hloov pauv hluav taws xob rau ntau zaus sib txawv tau qhia.
1 MHZ
Tsis pub dhau 1MHZ, feem ntau yog vim muaj kev cuam tshuam kev sib txawv. Kev daws yog raws li nram no:
Qhov voltage nce X muaj peev xwm;
Ntxiv qhov sib txawv hom inductance;
Cov khoom siv hluav taws xob ntse tuaj yeem ua tiav los ntawm PI lim (nws pom zoo tias cov electrolytic capacitors nyob ze rau lub transformer tuaj yeem xaiv kom loj dua).
1 MHZ - 5 MHZ
1mhz-5mhz, qhov sib txawv hom hom sib xyaw ua ke, series ntawm X capacitors txuas nyob rau hauv parallel ntawm cov tswv yim kawg yog siv los lim tawm cov kev cuam tshuam sib txawv thiab txheeb xyuas qhov kev cuam tshuam dab tsi tsis txaus siab thiab daws qhov teeb meem:
Lub zog muaj peev xwm ntawm X tuaj yeem hloov kho los ntawm kev cuam tshuam ntawm hom sib txawv, thiab cov inductors ntawm hom sib txawv tuaj yeem raug ntxiv los kho qhov inductance ntawm qhov sib txawv.
Hom hom inductance tuaj yeem muab ntxiv kom dhau tus qauv ntawm hom kev cuam tshuam, thiab tsim nyog inductance tuaj yeem xaiv los tiv thaiv.
Cov cuab yeej tseem tuaj yeem hloov pauv cov yam ntxwv ntawm lub rectifier diode, ib khub ntawm cov diodes ceev xws li FR107 thiab ib khub ntawm cov rectifier diodes 1N4007.
Ntau tshaj 5 MHZ
Kev cuam tshuam ntawm kev sib chwv feem ntau yog tshaj 5M, thiab txoj kev ntawm kev tiv thaiv kev sib chwv tau txais yuav. Rau rooj plaub hauv av, cov nplhaib sib nqus ib ncig ntawm 2-3 tig rau hauv av xaim yuav ua rau muaj kev cuam tshuam ntau dua 10MHZ. Yuav nyob ze rau lub transformer ntawm hlau core adhesive tooj liab ntawv ci, tooj liab ntawv ci kaw nplhaib. Qhov luaj li cas ntawm shunt capacitance ntawm lub absorber thiab thawj loj circuits rau kev ua cov nram qab kawg tso zis rectifier.
20-30 MHZ
Qhov hloov pauv tuaj yeem kho lub peev xwm ntawm av Y2 lossis hloov txoj haujlwm ntawm Y2 capacitance.
Y1 txoj haujlwm capacitance thiab qhov ntsuas qhov tseem ceeb ntawm thawj thiab thib ob sab yog kho los ntawm cov npoo.
Copper foil qhob cij sab nraum lub transformer; Lub innermost txheej ntawm lub transformer yog shielded. Kho qhov kev npaj ntawm windings ntawm transformer.
Quadrature hloov PCBLAYOUT;
Me hom hom inductance qhov txhab nrog ob kab nyob rau hauv pem hauv ntej ntawm lub ntsiab tso zis kab;
Lub RC lim yog sib npaug ntawm ob qho kawg ntawm cov zis rectifier raj thiab cov kev ntsuas tsim nyog raug kho.
Tam sim no, BEADCORE tau ntxiv ntawm qhov hloov pauv thiab MOSFET.
Siv ib tug me me capacitor rau input voltage pin ntawm lub transformer.
Tam sim no tuaj yeem tsav los ntawm MOS resistor loj.