Chidule: Mapangidwe amagetsi osakanikirana PCB ndizovuta kwambiri. Maonekedwe ndi ma waya a zigawo ndi kukonza kwa magetsi ndi waya pansi zidzakhudza mwachindunji magwiridwe antchito a dera ndi magwiridwe antchito a electromagnetic. Kapangidwe ka magawo a nthaka ndi mphamvu zomwe zafotokozedwa m’nkhaniyi zitha kukulitsa magwiridwe antchito a mabwalo osakanikirana.

Kodi mungachepetse bwanji kusokoneza pakati pa chizindikiro cha digito ndi chizindikiro cha analogi? Tisanapange, tiyenera kumvetsetsa mfundo ziwiri zofananira ndi electromagnetic compatibility (EMC): Mfundo yoyamba ndikuchepetsa gawo la loop yomwe ilipo; Mfundo yachiwiri ndi yakuti dongosololi limagwiritsa ntchito malo amodzi okha. M’malo mwake, ngati dongosololi lili ndi ndege ziwiri zowonetsera, ndizotheka kupanga dipole antenna (Zindikirani: kukula kwa ma radiation a antenna yaing’ono ya dipole ndi yofanana ndi kutalika kwa mzere, kuchuluka kwa kayendedwe kameneka ndi mafupipafupi); ndipo ngati chizindikiro sichingadutse momwe zingathere Kubwereranso kwa chipika chaching’ono kungapangitse mlongoti waukulu wa loop (Zindikirani: kukula kwa ma radiation a antenna ang’onoang’ono a loop ndi ofanana ndi malo ozungulira, omwe akuyenda mozungulira, ndi lalikulu. pafupipafupi). Pewani zochitika ziwirizi momwe mungathere pakupanga.

Zimalangizidwa kuti zilekanitse nthaka ya digito ndi nthaka ya analogi pa bolodi lozungulira losakanikirana, kotero kuti kudzipatula pakati pa nthaka ya digito ndi nthaka ya analogi kungapezeke. Ngakhale kuti njirayi ndi yotheka, pali mavuto ambiri omwe angakhalepo, makamaka m’makina akuluakulu ovuta. Vuto lalikulu kwambiri ndikuti silingayendetsedwe kudutsa kusiyana kwa magawo. Gawo la magawo likangoyendetsedwa, ma radiation a electromagnetic ndi ma signal crosstalk amakula kwambiri. Vuto lofala kwambiri pamapangidwe a PCB ndikuti mzere wamawu umadutsa malo ogawidwa kapena magetsi ndikupanga mavuto a EMI.

Momwe mungakwaniritsire mapangidwe ogawa a PCB osakanikirana

Monga momwe tawonetsera pa Chithunzi 1, timagwiritsa ntchito njira yogawanitsa yomwe tatchulayi, ndipo mzere wa chizindikiro umadutsa kusiyana pakati pa zifukwa ziwirizi. Kodi njira yobwerera kwa ma sigino apano ndi iti? Poganiza kuti zifukwa ziwiri zomwe zimagawanika zimagwirizanitsidwa palimodzi (kawirikawiri kugwirizana kwa mfundo imodzi pamalo enaake), pakadali pano, pansi pa nthaka idzapanga chipika chachikulu. Kuthamanga kwamphamvu kwambiri komwe kumadutsa pamtunda waukulu kumapanga ma radiation ndi inductance yapamwamba. Ngati mawonekedwe otsika a analoji akuyenda mumtsinje waukulu, zamakono zimasokonezedwa mosavuta ndi zizindikiro zakunja. Choipa kwambiri ndi chakuti pamene zifukwa zogawanika zimagwirizanitsidwa palimodzi pamagetsi, phokoso lalikulu kwambiri lamakono lidzapangidwa. Kuphatikiza apo, nthaka ya analogi ndi nthaka ya digito imalumikizidwa ndi waya wautali kuti apange mlongoti wa dipole.

Kumvetsetsa njira ndi njira yobwereranso pansi ndiye chinsinsi chothandizira kamangidwe ka bolodi losakanikirana. Akatswiri ambiri opanga mapangidwe amangoganizira kumene chizindikiro chikuyenda, ndikunyalanyaza njira yeniyeni yapano. Ngati nthaka wosanjikiza iyenera kugawidwa, ndipo mawaya ayenera kuyendetsedwa kudutsa pakati pa magawano, kugwirizana kwa mfundo imodzi kungapangidwe pakati pa zifukwa zogawanika kuti apange mlatho wogwirizanitsa pakati pa zifukwa ziwiri, ndiyeno mawaya kupyolera mu mlatho wogwirizanitsa. . Mwanjira iyi, njira yobwereranso yolunjika ikhoza kuperekedwa pansi pa mzere uliwonse wa chizindikiro, kotero kuti malo ozungulira omwe amapangidwa ndi ochepa.

Kugwiritsa ntchito zida zodzipatula zowoneka bwino kapena zosinthira zimathanso kukwaniritsa chizindikiritso pagawo la magawo. Kwa oyamba, ndi chizindikiro cha kuwala chomwe chimadutsa kusiyana kwa magawo; Pankhani ya transformer, ndi mphamvu ya maginito yomwe imadutsa kusiyana kwa magawo. Njira ina yotheka ndiyo kugwiritsa ntchito mazizindikiro osiyanasiyana: chizindikirocho chimayenda kuchokera pamzere umodzi ndikubwerera kuchokera ku mzere wina. Pankhaniyi, nthaka sikufunika ngati njira yobwerera.

Kuti tifufuze mozama kusokoneza kwa ma siginecha a digito ku ma siginecha a analogi, choyamba tiyenera kumvetsetsa mawonekedwe a mafunde apamwamba kwambiri. Kwa mafunde othamanga kwambiri, nthawi zonse sankhani njira yokhala ndi impedance yocheperako (otsika kwambiri inductance) komanso molunjika pansi pa chizindikirocho, kotero kuti mphamvu yobwerera idzadutsa pamtunda wozungulira, mosasamala kanthu kuti gawo loyandikana ndilo gawo la mphamvu kapena pansi. .

Pantchito yeniyeni, nthawi zambiri imakonda kugwiritsa ntchito malo ogwirizana, ndikugawa PCB kukhala gawo la analogi ndi gawo la digito. Chizindikiro cha analogi chimayendetsedwa m’dera la analogi la zigawo zonse za bolodi, ndipo chizindikiro cha digito chimayendetsedwa m’dera la digito. Pamenepa, chizindikiro cha digito chobwerera panopa sichidzalowa mu malo a chizindikiro cha analogi.

Pokhapokha chizindikiro cha digito chikalumikizidwa pagawo la analogi la bolodi la dera kapena chizindikiro cha analogi chikugwiritsidwa ntchito pagawo la digito la bolodi la dera, kusokoneza kwa chizindikiro cha digito ku chizindikiro cha analogi kudzawonekera. Vuto lamtunduwu silimachitika chifukwa palibe malo ogawanika, chifukwa chenichenicho ndi waya wosayenera wa chizindikiro cha digito.

Mapangidwe a PCB amatenga malo ogwirizana, kudzera pagawo la digito ndi magawo a analogi ndi mawaya oyenerera, nthawi zambiri amatha kuthana ndi zovuta zina zovuta komanso zovuta zamawaya, ndipo nthawi yomweyo, sizingabweretse mavuto omwe amabwera chifukwa cha kugawanika kwa nthaka. Pankhaniyi, masanjidwe ndi kugawa magawo amakhala chinsinsi chodziwira zabwino ndi zoyipa za kapangidwe kake. Ngati masanjidwewo ndi omveka, digito pansi pano idzakhala yocheperako ku gawo la digito la bolodi la dera ndipo silingasokoneze chizindikiro cha analogi. Mawaya oterowo amayenera kuyang’aniridwa mosamala ndikuwonetsetsa kuti malamulo amawaya amatsatiridwa 100%. Kupanda kutero, kuwongolera kolakwika kwa mzere wolumikizira kumawononga bolodi yabwino kwambiri.

Mukalumikiza malo a analogi ndi mapini a digito a chosinthira cha A/D palimodzi, opanga ma A/D ambiri opanga ma A/D anganene kuti: Lumikizani mapini a AGND ndi DGND kumalo otsika omwewo otsika kwambiri kudzera panjira yayifupi kwambiri. (Zindikirani: Chifukwa chakuti ma chips ambiri a A / D osinthira samagwirizanitsa malo a analogi ndi pansi pa digito palimodzi, malo a analogi ndi digito ayenera kulumikizidwa kudzera m’mapini akunja.) Kusokoneza kulikonse kwakunja komwe kumagwirizana ndi DGND kudzadutsa mphamvu ya parasitic. Phokoso la digito lochulukirapo limaphatikizidwa ndi ma analogi mkati mwa IC. Malinga ndi malingaliro awa, muyenera kulumikiza zikhomo za AGND ndi DGND za chosinthira A/D ku malo a analogi, koma njira iyi idzayambitsa mavuto monga ngati malo otsetsereka a digito ya digito decoupling capacitor ayenera kulumikizidwa ku malo a analogi. kapena malo a digito.

Momwe mungakwaniritsire mapangidwe ogawa a PCB osakanikirana

Ngati makinawo ali ndi chosinthira chimodzi chokha cha A/D, mavuto omwe ali pamwambawa amatha kuthetsedwa mosavuta. Monga momwe tawonetsera pa Chithunzi 3, gawani pansi, ndikugwirizanitsa malo a analogi ndi digito pansi pa chosinthira A / D. Potengera njirayi, ndikofunikira kuwonetsetsa kuti m’lifupi mwa mlatho wolumikizana pakati pazigawo ziwirizo ndi zofanana ndi m’lifupi mwa IC, ndipo mzere uliwonse wazizindikiro sungathe kuwoloka malire.

Ngati pali otembenuza ambiri a A/D mu dongosolo, mwachitsanzo, momwe mungalumikizire otembenuza 10 A/D? Ngati nthaka ya analogi ndi digito imagwirizanitsidwa palimodzi pansi pa chosinthira chilichonse cha A / D, kugwirizana kwa mfundo zambiri kumapangidwa, ndipo kudzipatula pakati pa nthaka ya analoji ndi nthaka ya digito sikuli kanthu. Ngati simukulumikiza motere, zimaphwanya zofunikira za wopanga.