PCB stacking ndichinthu chofunikira kudziwa momwe EMC imagwirira ntchito pazogulitsa. Kuyala bwino kumatha kukhala kothandiza kwambiri pakuchepetsa ma radiation kuchokera ku PCB loop (masiyanidwe amachitidwe), komanso zingwe zolumikizidwa ku bolodi (common mode emission).

Kumbali inayi, kugwa koyipa kumatha kukulitsa kuwala kwa njira zonse ziwiri. Zinthu zinayi ndizofunikira pakuwunika kwa mbale:

1. Chiwerengero cha zigawo;

2. Chiwerengero ndi mtundu wa zigawo zomwe zagwiritsidwa ntchito (mphamvu ndi / kapena nthaka);

3. Dongosolo kapena dongosolo la zigawo;

4. Kutalika pakati pa zigawo.

Kawirikawiri chiwerengero chazigawo chimaganiziridwa. Nthawi zambiri, zinthu zina zitatuzi ndizofunikanso, ndipo chachinayi nthawi zina sichimadziwika ndi wopanga PCB. Mukazindikira kuchuluka kwa zigawo, ganizirani izi:

1. Zizindikiro zambiri ndi mtengo wa zingwe;

2. Pafupipafupi;

3. Kodi malonda akuyenera kukwaniritsa zofunikira pakukhazikitsa Class A kapena Class B?

4. PCB ili m’nyumba zotetezedwa kapena zosatetezedwa;

5. Maluso aukadaulo a EMC a gulu lopanga.

Kawirikawiri nthawi yoyamba yokha imalingaliridwa. Zowonadi, zinthu zonse zinali zofunika ndipo ziyenera kuganiziridwa chimodzimodzi. Chinthu chomaliza ichi ndi chofunikira kwambiri ndipo sichiyenera kunyalanyazidwa ngati mapangidwe abwino atha kukwaniritsidwa munthawi yochepa komanso mtengo wake.

Mbale yama multilayer yogwiritsa ntchito nthaka ndi / kapena ndege yamagetsi imapereka kuchepa kwakukulu kwa kutulutsa kwa radiation poyerekeza ndi mbale yosanjikiza iwiri. Lamulo lanthu lonse logwiritsidwa ntchito ndikuti mbale yazinthu zinayi imatulutsa ma radiation ochepa a 15dB kuposa mbale ziwiri, zinthu zina zonse ndizofanana. Bolodi lokhala ndi malo athyathyathya ndilabwino kuposa bolodi lopanda mosabisa pazifukwa izi:

1. Amalola kuti ziziyendetsedwa ngati mizere yama microstrip (kapena mizere ya riboni). Nyumbazi zimayendetsedwa ndi mizere yolumikizira ma impedance yokhala ndi cheza chocheperako poyerekeza ndi zingwe zamagetsi zomwe zimagwiritsidwa ntchito pamatumba awiri;

2. Ndege yapansi imachepetsa kwambiri kutsekemera kwapansi (motero phokoso lapansi).

Ngakhale ma mbale awiri agwiritsidwa ntchito bwino m’malo osatsekedwa a 20-25mhz, milanduyi ndiyosiyana ndi kulamulira. Pamwamba pafupifupi 10-15mhz, magawo angapo amitundu yambiri amayenera kulingaliridwa.

Pali zolinga zisanu zomwe muyenera kuyesa kukwaniritsa mukamagwiritsa ntchito bolodi yama multilayer. Ali:

1. Chizindikiro chachizindikiro nthawi zonse chimayenera kukhala moyandikana ndi ndege;

2. Mzere wazizindikiro uyenera kulumikizidwa mwamphamvu (pafupi) ndi ndege yoyandikana nayo;

3, ndege yamagetsi ndi ndege yapansi iyenera kuphatikizidwa;

4, chizindikiritso chothamanga kwambiri chiyenera kuikidwa m’manda pakati pa ndege ziwiri, ndege imatha kugwira ntchito yoteteza, ndipo imatha kupondereza kutentha kwa mzere wothamanga kwambiri;

5. Ndege zingapo zokhazikitsira pansi zili ndi maubwino ambiri chifukwa zimachepetsa kukhazikika kwa ndege ndikuchepetsa cheza chofala.

Mwambiri, tikukumana ndi chisankho pakati pa kulumikizana kwa ma siginolo / ndege (Cholinga 2) ndi kulumikizana kwapafupi ndi ndege / ndege (cholinga 3). Pogwiritsa ntchito njira zamakono za PCB, kusanja kwa mbale pakati pamagetsi oyandikira ndi ndege yapansi sikokwanira kupereka kuchepa kokwanira pansi pa 500 MHz.

Chifukwa chake, kulumikizana kuyenera kuthandizidwa ndi njira zina, ndipo nthawi zambiri tiyenera kusankha kulumikizana kolimba pakati pa siginecha ndi ndege yomwe ikubwerera. Ubwino wolumikizana mwamphamvu pakati pazosanjikiza mbendera ndi ndege yomwe ikubwerera iposanso zovuta zomwe zimadza chifukwa chakuchepa kwamphamvu pakati pa ndege.

Magawo asanu ndi atatu ndiye nambala yocheperako yomwe ingagwiritsidwe ntchito kukwaniritsa zolinga zisanu zonsezi. Zina mwazolingazi ziyenera kusinthidwa pamabodi anayi – ndi asanu ndi limodzi. Pansi pa izi, muyenera kudziwa zolinga zomwe zili zofunika kwambiri pakapangidwe kamene kali pafupi.

Ndime yomwe ili pamwambayi siyiyenera kutanthauziridwa kutanthauza kuti simungathe kupanga EMC yabwino pagulu lazinayi kapena zisanu ndi chimodzi, momwe mungathere. Zikungowonetsa kuti sizolinga zonse zomwe zingakwaniritsidwe nthawi imodzi ndikuti kunyengerera kumafunikira.

Popeza zolinga zonse za EMC zimatheka ndi zigawo zisanu ndi zitatu, palibe chifukwa chogwiritsa ntchito zigawo zopitilira zisanu ndi zitatu kupatula kuti mukhazikitse zigawo zina zowonetsera mayendedwe.

Kuchokera pamawonekedwe amakanema, cholinga china chabwino ndikupanga gawo la PCB bolodi lofanana (kapena loyenera) kuti lisagwere.

Mwachitsanzo, pa bolodi lachisanu ndi chitatu, ngati gawo lachiwiri ndi ndege, ndiye kuti gawo lachisanu ndi chiwiri liyeneranso kukhala ndege.

Chifukwa chake, mawonekedwe onse omwe afotokozedwera pano amagwiritsa ntchito mawonekedwe ofanana kapena oyenera. Ngati malo osakanikirana kapena osagwirizana amaloledwa, ndizotheka kupanga zosintha zina.

Gulu limodzi losanjikiza

Chingwe chodziwika bwino kwambiri chachinayi chikuwonetsedwa mu Chithunzi 1 (ndege yamagetsi ndi ndege zapansi zimasinthana). Amakhala ndi zigawo zinayi zogawika bwino ndi ndege yamkati yamkati ndi ndege yapansi. Magawo awiri amtundu wakunja nthawi zambiri amakhala ndi mayendedwe olumikizira.

Ngakhale kuti nyumbayi ndiyabwino kuposa magawo awiri, ili ndi zinthu zina zosafunikira.

Pamndandanda wazolinga mu Gawo 1, muluwu umangokwaniritsa chandamale (1). Ngati zigawozo zidagawika chimodzimodzi, pamakhala kusiyana kwakukulu pakati pa siginizo ndi ndege yobwerera. Palinso kusiyana kwakukulu pakati pa ndege yamagetsi ndi ndege yapansi.

Pa bolodi lachinayi, sitingathe kukonza zovuta zonse nthawi imodzi, chifukwa chake tiyenera kusankha zomwe zili zofunika kwambiri kwa ife.

Monga tanenera kale, kuchuluka kwamagetsi pakati pamagetsi oyandikira ndi ndege yapansi sikokwanira kupereka kuwongolera kokwanira pogwiritsa ntchito njira zamakono zopangira PCB.

Decoupling iyenera kuchitidwa ndi njira zina, ndipo tiyenera kusankha kulumikizana kolimba pakati pa siginecha ndi ndege yomwe ikubwerera. Ubwino wolumikizana mwamphamvu pakati pazosanjikiza mbendera ndi ndege yobwerera pakadali pano iposa zovuta zakutayika pang’ono kwa ma interlayer capacitance.

Chifukwa chake, njira yosavuta yosinthira magwiridwe antchito a EMC ya mbale zinayi ndikubweretsa ma siginolo pafupi ndi ndege momwe angathere. 10mil), ndipo amagwiritsa ntchito dielectric yayikulu pakati pa magetsi ndi ndege yapansi (> 40mil), monga tikuonera Chithunzi 2.

Izi zili ndi zabwino zitatu komanso zovuta zochepa. Malo okhala ndi ma siginolo ndi ocheperako, ma radiation amtundu wochepa kwambiri amapangidwa. Potenga mphindi 5mil pakati pa zingwe zamagetsi ndi ndege, kuchepa kwa ma radiation kwa 10dB kapena kupitilira apo kungapezeke pokhudzana ndi kapangidwe kofanana.

Chachiwiri, kulumikizana kolimba kwa zingwe zamagetsi pansi kumachepetsa kutayika kwa pulaneti (inductance), motero kumachepetsa cheza chofala cha chingwe cholumikizidwa ndi bolodi.

Chachitatu, kulumikizana kolimba kwa ndege ku ndege kumachepetsa crosstalk pakati pa zingwe. Pakukhazikika kwa chingwe, crosstalk ndiyofanana ndi lalikulu la kutalika kwa chingwe. Iyi ndi imodzi mwanjira zosavuta, zotsika mtengo, komanso zomwe anthu ambiri amazinyalanyaza zochepetsera cheza chochokera ku PCB yazaka zinayi.

Pogwiritsa ntchito izi, timakwaniritsa zolinga zonse ziwiri (1) ndi (2).

Ndi ziti zina zomwe zingachitike pamakonzedwe amiyala inayi? Titha kugwiritsira ntchito kapangidwe kake kosasinthasintha, monga kusinthana kwa siginecha ndi wosanjikiza ndege mu Chithunzi 2 kuti tipeze kuwonongeka komwe kukuwonetsedwa mu Chithunzi 3A.

Ubwino waukulu wokulutsaku ndikuti ndege yakunja imapereka chitetezo chamayendedwe osanjikiza mkatikati. Chosavuta ndichakuti ndege yapansi imatha kudulidwa kwambiri ndi mapaketi apamwamba kwambiri pa PCB. Izi zitha kuchepetsedwa pang’ono potembenuza ndegeyo, kuyika ndege yamagetsi mbali ya chinthucho, ndikuyika ndege yapansi mbali ina ya bolodi.

Chachiwiri, anthu ena sakonda kukhala ndi ndege yamagetsi yowonekera, ndipo chachitatu, zikwangwani zoikika zimapangitsa kuti zikhale zovuta kukonzanso gululo. Masewerowa amakwaniritsa cholinga (1), (2), ndikukwaniritsa pang’ono cholinga (4).

Awiri mwamavuto atatuwa amatha kuchepetsedwa ndi kugundana komwe kukuwonetsedwa pa Chithunzi 3B, pomwe ndege ziwiri zakunja ndi ndege zapansi ndipo magetsi amayendetsedwa pa ndege yolozera ngati waya.Mphamvu yamagetsi idzayendetsedwa mwachangu pogwiritsa ntchito zingwe zazingwe zazizindikiro.

Zina mwazabwino zowonjezera izi ndi izi:

(1) Ndege ziwirizi zimapereka njira zotsikira kwambiri, motero zimachepetsa cheza chofiyira wamba;

(2) Ndege ziwiri zapansi zimatha kusokedwa limodzi m’mbali mwa mbale kuti zisindikize zikwangwani zonse mu khola la Faraday.

Kuchokera pamalingaliro a EMC, kuyika uku, ngati kwachita bwino, kumatha kukhala kuyala kwabwino kwambiri kwa ma PCB anayi. Tsopano takwaniritsa zolinga (1), (2), (4) ndi (5) zokhala ndi bolodi limodzi lokhala ndi zigawo zinayi.

Chithunzi 4 chikuwonetsa kuthekera kwachinayi, osati mwachizolowezi, koma komwe kungachite bwino. Izi zikufanana ndi Chithunzi 2, koma ndege yapansi imagwiritsidwa ntchito m’malo mwa ndege yamagetsi, ndipo magetsi amakhala ngati chofufuzira pamizere yolumikizira waya.

Izi zikuthana ndi zovuta zomwe zatchulidwazi komanso zimaperekanso zovuta chifukwa cha ndege ziwiri zapansi. Komabe, ndegezi sizimateteza. Kusintha kumeneku kumakwaniritsa zolinga (1), (2), ndi (5), koma sizikhutiritsa zolinga (3) kapena (4).

Chifukwa chake, monga mukuwonera pali zosankha zingapo pazosanjikiza zinayi kuposa momwe mungaganizire koyambirira, ndipo ndizotheka kukwaniritsa zolinga zathu zisanu mwa zisanu ndi zinayi za PCBS. Kuchokera pamalingaliro a EMC, magawo a 2, 3b, ndi 4 onse amagwira ntchito bwino.

6 bolodi wosanjikiza

Mabungwe ambiri osanjikiza asanu ndi limodzi amakhala ndi zigawo zinayi zolumikizira ma waya ndi zigawo ziwiri za ndege, ndipo matabwa asanu ndi limodzi amakhala apamwamba kuposa matabwa anayi kuchokera ku EMC.

Chithunzi 5 chikuwonetsa mawonekedwe osunthika omwe sangathe kugwiritsidwa ntchito pa bolodi la magawo asanu ndi limodzi.

Ndegezi sizimateteza pazosanjikiza, ndipo zigawo ziwiri (1 ndi 6) sizoyandikana ndi ndege. Kukonzekera kumeneku kumangogwira ntchito ngati ma siginolo onse oyendetsedwa amayendetsedwa pakadutsa 2 ndi 5, ndipo ma siginolo otsika kwambiri, kapena kuposa pamenepo, palibe zingwe zazingwe (ma pads a solder okha) omwe amayendetsedwa magawo 1 ndi 6.

Ngati agwiritsidwa ntchito, malo aliwonse osagwiritsidwa ntchito pansi 1 ndi 6 akuyenera kukonzedwa ndi viAS yolumikizidwa pansi pansi m’malo ambiri momwe angathere.

Kusintha kumeneku kumakwaniritsa chimodzi mwazolinga zathu zoyambirira (Cholinga 3).

Ndi zigawo zisanu ndi chimodzi zomwe zilipo, mfundo yopereka zigawo ziwiri zoyikidwa m’miyala yothamanga kwambiri (monga zikuwonetsedwa pa Chithunzi 3) imagwiritsidwa ntchito mosavuta, monga zikuwonetsedwa pa Chithunzi 6. Kukonzekera kumeneku kumaperekanso zigawo ziwiri zapansi pazizindikiro zothamanga kwambiri.

Izi mwina ndizofala kwambiri magawo asanu ndi limodzi ndipo zitha kukhala zothandiza kwambiri pakuwongolera kutulutsa kwamagetsi mukachita bwino. Kusintha kumeneku kumakwaniritsa cholinga 1,2,4, koma osati cholinga 3,5. Chosavuta chake chachikulu ndikulekanitsidwa kwa ndege zamagetsi ndi ndege zapansi.

Chifukwa chodzipatula kumeneku, palibe ma interplane capacitance ambiri pakati pa ndege yamagetsi ndi ndege yapansi, chifukwa chake kuyeserera koyenera kuyenera kuchitidwa kuti athane ndi izi. Kuti mumve zambiri zakuchotsera, onani malangizo athu ochepetsa njira.

Kapangidwe kofanana, koyenda bwino kakang’ono kosanjikizika kasanu ndi kamodzi kakuwonetsedwa Chithunzi 7.

H1 imayimira njira yopingasa yopangira ma 1, V1 imayimira njira yolunjika ya siginecha 1, H2 ndi V2 zikuyimira tanthauzo lomwelo la siginecha 2, ndipo mwayi wamtunduwu ndikuti mayendedwe amachitidwe nthawi zonse amatanthauza ndege yomweyo.

Kuti mumvetse chifukwa chake izi ndi zofunika, onani gawo la ndege zolozera anthu mu Gawo 6. Chosavuta ndichakuti wosanjikiza 1 ndi wosanjikiza 6 sizitetezedwa.

Chifukwa chake, wosanjikiza wazizindikiro akuyenera kukhala pafupi kwambiri ndi ndege yake yoyandikira ndipo pakati pakatikati pa malo osanjikiza ayenera kugwiritsidwa ntchito popanga mbale yolimba ya mbale. Malo osanjikizana a mainchesi 0.060 mainchesi atha kukhala 0.005 “/ 0.005” / 0.040 “/ 0.005” / 0.005 “/ 0.005”. Kapangidwe kameneka amakwaniritsa Zolinga 1 ndi 2, koma osati zolinga 3, 4 kapena 5.

Mbale ina yosanjikiza isanu ndi umodzi yokhala ndi magwiridwe antchito kwambiri ikuwonetsedwa mu Chithunzi 8. Imakhala ndi zikwangwani ziwiri zoyikidwako mbendera komanso ndege zoyandikira zamagetsi ndi ndege zapansi kuti zikwaniritse zolinga zonse zisanu. Komabe, vuto lalikulu ndikuti limangokhala ndi zingwe ziwiri, chifukwa chake siligwiritsidwa ntchito pafupipafupi.

Masamba asanu ndi limodzi ndiosavuta kupeza mayendedwe abwino amagetsi kuposa mbale zinayi. Tilinso ndi mwayi wokhala ndi mayendedwe anayi amawu m’malo mongokhala awiri.

Monga momwe zidalili ndi bolodi lazingwe zinayi, ma PCB asanu ndi limodzi adakwaniritsa zinayi mwa zolinga zisanu. Zolinga zonse zisanu zitha kukwaniritsidwa ngati tingokhala ndi zigawo ziwiri zodutsa. Kapangidwe ka Chithunzi 6, Chithunzi 7, ndi Chithunzi 8 zonse zimagwira bwino ntchito kuchokera ku EMC.