I ka hoʻolālā EMC o PCB, ʻo ka hopohopo mua ka hoʻonohonoho papa; Hoʻokomo ʻia nā papa o ka papa i ka lako mana, papa honua a me ka hōʻailona hōʻailona. I ka hoʻolālā ʻana o nā huahana EMC, ma waho o ke koho ʻana o nā ʻāpana a me ka hoʻolālā kaapuni, maikaʻi pū kekahi hoʻolālā PCB maikaʻi.

The key to the EMC design of PCB is to minimize the backflow area and make the backflow path flow in the direction we designed. ʻO ka hoʻolālā papa ke kumu o PCB, pehea e hana ai i kahi hana maikaʻi o ka hoʻolālā papa PCB e hana i ka hopena EMC o PCB maikaʻi?

I. Nā manaʻo hoʻolālā o ka papa PCB

The core of PCB laminated EMC planning and design is to reasonably plan signal backflow path to minimize the backflow area of signal from the board mirror layer, so as to eliminate or minimize magnetic flux.

Pāhi aniani papa hoʻokahi

ʻO ke aniani ʻāpana kahi papa holoʻokoʻa o ka papa pelane pale keleawe keleawe (ka mana o ka mana, ka papa lepo) pili i ka papa hōʻailona ma loko o ka PCB. ʻO nā hana nui penei:

(1) Hoʻoemi i ke kani o ke kua i hope: hiki i ka papa aniani ke hāʻawi i kahi ala impedance haʻahaʻa no ka backflow papa hōʻailona, ​​keu hoʻi ke nui kahe i kēia manawa i ka ʻōnaehana hoʻoili mana, ʻoi aku ka maopopo o ka hana o ka papa aniani.

(2) EMI hoʻemi: ʻo ke ola o ke aniani aniani e hoʻoliʻiliʻi i ka wahi o ka loop loop i hoʻokumu ʻia e ka hōʻailona a reflux a hoʻoliʻiliʻi EMI;

(3) hoʻoliʻiliʻi crosstalk: kōkua e kaohi i ka pilikia crosstalk ma waena o nā laina hōʻailona ma ke kaʻapuni uila wikiwiki, hoʻololi i ke kiʻekiʻe o ka laina hōʻailona mai ka papa aniani, hiki iā ʻoe ke kaohi i ka crosstalk ma waena o nā laina hōʻailona, ​​ka liʻiliʻi o ke kiʻekiʻe, ka liʻiliʻi ka crosstalk;

(4) Ka mālama Impedance e pale ai i ke aka hōʻailona.

Koho o ke aniani aniani

(1) Hiki ke hoʻohana ʻia ka lako mana a me ka mokulele honua e like me ka mokulele kūmole, a loaʻa kahi hopena pale ma nā uea kūloko.

(2) Ma ke ʻano kamaʻilio, he ʻano nui ka impedance kiʻekiʻe o ka mokulele, a aia kekahi ʻokoʻa nui me ka pae kūmole, a ʻo ka pinepine pinepine pinepine i ka mokulele uila he nui ia;

(3) Mai ke kuanaʻike o ka pale ʻana, hoʻokumu ʻia ka papa honua a hoʻohana ʻia ma ke ʻano he kiko kuhikuhi o ka pae kūmole, a ʻoi aku ka maikaʻi o ka hopena pale ma mua o ka mokulele mana;

(4) Ke koho ʻana i ka mokulele kūmole, e ʻoi aku ka maikaʻi o ka mokulele honua, a koho ʻia ka mokulele uila i kekona

Two, magnetic flux cancellation principle

Wahi a nā kaulike a Maxwell, ua lawe ʻia nā hana uila a me nā mākēneki ma waena o nā kino i hoʻokaʻawale ʻia a i ʻole nā ​​au i lawe ʻia ma o ka waena waena ma waena o lākou, inā he hakahaka a mea paʻa paha. In a PCB, the flux is always propagated in the transmission line. If the rf backflow path is parallel to the corresponding signal path, the flux on the backflow path is in the opposite direction to that on the signal path, then they are superimposed on each other, and the effect of flux cancellation is obtained.

Ke ʻano o ka hoʻokahuli flux magnet

ʻO ke kumu o ka hoʻōki flux ka kaohi o ke ala backflow hōʻailona, ​​e like me ka mea i hōʻike ʻia i ke kiʻi penei:

Wehewehe ka lula ʻākau i ka hopena o ka hoʻopau ʻana o ka flux magnet

Pehea e hoʻohana ai i ka lula lima ʻākau e wehewehe i ka hopena o ka hoʻohemo ʻana o ka magnetic hopena ke pili ka papa hōʻailona i ka stratum penei:

(1) Ke kahe ana kahi au i loko o ka uea, e hoʻokumu ʻia kahi māla ʻume mākenēki a puni ka uea, a hoʻoholo ʻia ke ʻaoʻao o ka mākia maneta e ka lula lima ʻākau.

(2) ke pili kokoke ʻelua i kekahi a kūlike i ka uea, e like me ka mea i hōʻike ʻia ma ke kiʻi ma lalo, ʻo kekahi o nā alakaʻi o ka uila e hoʻokahe, kahi e lawe i ka uila e kahe, inā kahe ka uila i loko o ka aia nā uea i kēia manawa a me kāna hōʻailona hoʻihoʻi i kēia manawa, a laila ua like nā ʻaoʻao ʻaoʻao ʻelua o ke au, no laila ua kaulike ko lākou kaha magnet, akā aia ke ʻaoʻao i ka ʻaoʻao,No laila hoʻopau lākou kekahi i kekahi.

ʻElima, ʻeono mau laʻana hoʻolālā papa

No nā papa ʻeono, makemake ʻia ka hoʻolālā 3

ʻIkepili:

(1) E pili ana ka papa hōʻailona me ka mokulele kūwaho, a ʻo S1, S2 a me S3 e pili pū ana me ka mokulele honua, ua hoʻokō ʻia ka hopena hoʻokahuli magnetic maikaʻi loa. No laila, ʻo S2 ka papa kuhikuhi hoʻokele makemake ʻia, a ukali ʻia e S3 a me S1.

(2) Pili ka mokulele uila i ka mokulele GND, liʻiliʻi loa ka mamao ma waena o nā mokulele, a loaʻa iā ia ka hopena hoʻokahuli magnetic maikaʻi loa a me ka impedance mokulele haʻahaʻa.

(3) Aia ka lako mana nui a me kāna lole palaoa e pili ana i ka papa 4 a me 5. Ke hoʻonohonoho ʻia ka mānoanoa o ka papa, e hoʻonui ʻia ke ākea ma waena o S2-P a hoʻēmi ʻia ke ākea ma waena o P-G2 (ʻo ka hoʻokaʻawale ma waena o ka papa E hoʻemi ʻia ʻo G1-S2), i mea e hōʻemi ai i ka impedance o ka mokulele mana a me ka hopena o ka lako mana ma S2.

No nā papa ʻeono, koho 4

ʻIkepili:

ʻOi aku ka kūpono o ka hoʻolālā 4 ma mua o ka Scheme 3 no kahi kūloko, kahi liʻiliʻi o nā koina hōʻailona, ​​hiki ke hāʻawi i kahi papa uila maikaʻi S2.

Ka hopena EMC ʻoi loa, hoʻolālā 2

ʻIkepili: Ma kēia ʻano, pili ka S1 a me ka S2, pili kokoke ʻo S3 a me S4, a ʻaʻole pili ʻo S3 a me S4 ​​i ka mokulele honua, no laila ʻilihuna ka hopena hoʻokahuli flux magnet.

ka hopena

Nā kumuhana kikoʻī o ka hoʻolālā papa PCB:

(1) Aia kahi mokulele honua holoʻokoʻa (pale kaua) ma lalo o ka ʻili o ka ʻili a me ka pae hoʻoheheʻe;

(2) E hoʻāʻo e hōʻalo i kahi pili pono o nā papa hōʻailona ʻelua;

(3) Pili nā ʻōkuene hōʻailona āpau i ka mokulele honua a hiki i ka hiki;

(4) Ka pae uila o ke alapine kiʻekiʻe, ka wikiwiki nui, uaki a me nā hōʻailona kī ʻē aʻe e pono i kahi mokulele honua e pili ana.