PCB Shielding Techniques yeEMI Kudzora uye EMC Kutevedzera

Chii chinonzi PCB Shielding?

Sezvo zvemazuva ano zvemagetsi zvawedzera kuoma uye compact, electromagnetic interference (EMI) uye electromagnetic kuenderana (EMC) zvave zvakakosha kufunga muPCB dhizaini. Nekuwedzera kwema frequency ekushanda uye kubatanidzwa kwakanyanya kwezvikamu, kutonga kwemagetsi emagetsi kwave kwakakosha kuve nechokwadi chekushanda uye kutevedza kwemidziyo yemagetsi. PCB kudzivirira inzira yakakosha inoshandiswa kuchengetedza masekete anoomesesa kubva mukukanganisika kwekunze, pamwe nekuve nekuburitsa zvinoburitswa nePCB pachayo.

Muchinyorwa chino, tichaongorora tekinoroji maficha ePCB kudzivirira, kusanganisira marudzi emidziyo yekudzivirira, nzira dzekugadzira dzinoshandiswa kurerutsa EMI, zvinoenderana neindasitiri zviyero, uye kukosha kweiyo chaiyo PCB kugadzira mukuwana kudzivirirwa kunoshanda.

Kunzwisisa EMI uye EMC

Electromagnetic interference (EMI) isimba chero ripi zvaro risingadiwe remagetsi rinokanganisa mashandiro emidziyo yemagetsi. Inogona kuratidza mumhando mbiri:

1. Radiated EMI: Mafungu eElectromagnetic anoburitswa kubva kutsime anofamba nemumhepo uye anokanganisa masisitimu ari pedyo.
2. Inoitiswa EMI: Ruzha rwemagetsi runofamba kuburikidza nemagetsi kana mitsetse yechiratidzo, inobata masekete zvakananga.

Nekune rimwe divi, electromagnetic kuenderana (EMC) inoreva kugona kwechigadzirwa kushanda munzvimbo yayo pasina kukonzera kana kukanganiswa neEMI. Izvi zvakakosha kuti ive nechokwadi chekushanda chaiko kwemidziyo ine ngozi, yakadai semidziyo yekurapa kana masisitimu emuchadenga, uye kutevedzera mirairo yepasi rose, seCISPR 32 yemidziyo yeruzivo rwemichina kana FCC Chikamu 15 chemagetsi ekutengesa muUS.

Zvinyorwa zveEMI muPCB Dhizaini

Iwo ekutanga masosi eEMI paPCB anosanganisira:

• High-frequency wachi zviratidzo: Aya masaini anoburitsa akasimba emagetsi minda anogona kukanganisa maseketi ari pedyo.
• Kuchinja magetsi: Kuchimbidza nekukurumidza kunogadzira ruzha rwepamusoro-frequency.
• Hurefu hwekuronda: Mateki asina kubviswa zvakanaka kana kufambiswa anogona kuita sema antenna, anopenya EMI.
• I / O interfaces: Tambo dzekunze dzakabatana nePCB dzinogona kusimudza kana kupenya EMI, ichiva antenna isingaite.

Kune yakakwirira-kumhanya dhizaini inoshanda pamusoro pe100 MHz, mutsauko wekufamba-famba uye impedance control inove yakakosha kudzikisa kuderedzwa kwechiratidzo uye EMI chizvarwa. Kunyanya kutarisisa kunofanirwa kupihwa kutonga nzira dzekudzoka uye kuderedza chiratidzo loop nzvimbo.

Kugadzira maPCB ane EMC Mafungiro

PCB yakagadzirwa zvakanaka inogona kuderedza zvakanyanya EMI uye kuvandudza kutevedzera EMC . Heano mamwe maitiro akakosha ekugadzira:

1. Ground Planes uye Layering: Kushandiswa kwendege dzepasi dzinoramba dziri mu-multi-layer PCBs inopa nzira yakaderera-impedance yekudzoka kwezviratidzo, izvo zvinoderedza loop inductance uye kuderedza kubudiswa kweradiated. Ndege dzepasi dzinoshandawo senhoo dzezviratidziro zvinodzikama, kuderedza crosstalk uye kunatsiridza kutendeseka kwechiratidzo. Paunenge uchigadzira akawanda-layer mabhodhi, zvakakosha kuti uchinje simba uye pasi pasi, sandwiching chiratidzo machira pakati pawo kuti uwedzere kudzivirira kushanda.
2. Trace Layout uye Routing: Yakafanira yekutevera nzira yakakosha mukudzikisa EMI. High-speed signal traces inofanira kuchengetwa ipfupi sezvinobvira kudzivirira kuita seantenna. Pamusoro pezvo, mitsetse inofanirwa kufambiswa pamusoro peiyo yakasimba pasi ndege kuti ideredze loop nzvimbo uye kuve nechokwadi chekudzoka ikozvino kunotevera nzira ipfupi. Kune masaini akakosha, senge mitsara yewachi, nzira yekusiyanisa inogona kushandiswa kudzima yakajairika-modhi ruzha.
3. Via Placement: Vias that transition high-speed signals pakati pePCB layers inofanira kuiswa zvine hungwaru kudzivirira kuumba zvisina kufanira stub urefu, izvo zvinogona kukonzera kuratidzira uye kupenya EMI. Kuisa pasi vias padhuze nechiratidzo vias kunobatsira kuchengetedza chiratidzo chekuvimbika uye kunoderedza njodzi yekugadzira zvinhu zvinopenya.
4. Decoupling uye Bypass Capacitors: Kushandiswa kwakakodzera kwe decoupling capacitors kwakakosha pakudzikisa EMI yakaitwa. Macapacitor anofanirwa kuiswa padhuze nepaanogona kune mapini emagetsi eICs kuti ape yakaderera-impedance nzira yekudzika pasi pakakwirira. Mune yakakwirira-frequency dhizaini, capacitor kukosha kunofanirwa kusarudzwa zvichibva pane resonant frequency, kuve nechokwadi kunoshanda kudzvinyirira ruzha mune inodiwa frequency renji.

Mhando dzePCB Shielding

Nzira dzinoverengeka dzakasiyana dzinogona kutorwa paunenge uchigadzira PCB ine EMI kudzivirira:

1. Metal Enclosures (Faraday Cage): Kushandiswa kwekeji yeFaraday yakavharwa zvakakwana yakakomberedza chikamu chakaoma chedunhu ndiyo imwe yenzira dzakanakisisa dzekudzivirira. Nhoo yesimbi, inowanzo gadzirwa nemhangura, nickel, kana aluminium, inotengeswa yakananga kuPCB pasi, inovhara zvakakosha zvikamu. Iyi nzira inopa yakanakisa dziviriro kubva kune ese ari maviri radiated uye akaitwa EMI. Izvo zvakaderera ndezvekuti nhovo inogona kuwedzera huremu uye kudzikisira kuwana kune zvikamu zvekuyedzwa kana kugadzirisa.
2. Embedded Ground Layers: Mu-multi-layer PCBs, kuwedzera dzimwe ndege dzepasi pakati pezvikamu zvezviratidzo zvinogona kunyatsoita senhovo, kuderedza-kutaurirana uye kuparadzanisa zviratidzo zvepamusoro-soro kubva kumagetsi emagetsi. Iyi nzira inonyanya kubatsira muHDI (High-Density Interconnect) magadzirirwo apo nzvimbo inogumira, uye kudzivirira kwechinyakare kungave kusingagoneke.
3. Conductive Gaskets: Nekudzivirira mune zvakavharirwa, conductive gaskets inogona kushandiswa kuchengetedza kuenderera kwemagetsi pakati pesimbi shielding zvikamu uku uchibvumira kushanduka kwemagetsi. Izvi zvinonyanya kubatsira mumagadzirirwo panodiwa kuyerera kwemhepo kana kupisa kwemafuta, senge muRF masisitimu.
4. Ferrite Beads uye Mafirita: Ferrite beads inowanzoshandiswa pamwe chete nePCB shielding kudzikamisa ruzha rwepamusoro-frequency. Izvi zvikamu zvinoiswa pamagetsi emagetsi kana zviratidzo zvekuvharira yakakwira-frequency EMI uku ichibvumira yakaderera-frequency masaini kuti apfuure. Iwo chishandiso chakakosha mukugadzirisa EMI yakaitwa, kunyanya mumatanho ekugovera magetsi.

Kudzivirira Zvishandiso Nezvinhu Zvazvo

Sarudzo yezvinhu zvePCB kudzivirira zvinoenderana neiyo frequency renji uye chimiro cheEMI kuvharwa. Zvishandiso zvakasiyana zvinoratidza mazinga akasiyana e conductivity uye magineti permeability, ayo anopesvedzera kushanda kwavo pama frequency akasiyana:

• mhangura: Inopa yakanakisa conductivity yemagetsi, ichiita kuti ive yakanaka kune yakaderera-frequency shielding. Mhangura inowanzoshandiswa kune ndege dzepasi uye simbi makeni muPCB magadzirirwo.
• aruminiyamu: Yakareruka uye inodhura-inoshanda, aluminium inopa yakanaka EMI kudzivirira mukati me-frequency renji.
• Nickel uye Nickel Alloys: Zvishandiso izvi zvinopa yakakwira magineti permeability, ichiita kuti ive yakakodzera kudzivirira masaini epamusoro-frequency uye kudzvanyirira mwenje wemagetsi. Nickel alloys anowanzo shandiswa mukushanda kwepamusoro-soro senge aerospace uye zvemagetsi zvemauto.
• Ferrites: Ferrites zvinhu zveceramic izvo zvinopa yakakwirira magineti permeability, kunyanya inoshanda kudzvanyirira yakakwira-frequency ruzha. Ivo vanowanzoshandiswa muchimiro ferrite bead kana cores.

Quantifying Shielding Kubudirira

Kushanda kwekudzivirira kunowanzoyerwa mumadecibel (dB), anomiririra chiyero chechiitiko chemagetsi emagetsi kumunda unofambiswa kuburikidza nenhoo. Yepamusoro dB maitiro anoratidza zvirinani kudzivirira kuita. Semuyenzaniso, yakajairika PCB nhovo inogona kupa attenuation muchikamu che60 kusvika 100 dB yemafrequency ari pakati pe100 MHz ne1 GHz. Kushanda kwenhoo kunoenderana nezvakati wandei:

• Hukobvu hwezvinhu zvinodzivirira: Zvishandiso zvakakora zvinowanzopa kudzikisira kuri nani.
• Kudzivirira kuenderera mberi: Chero mapundu kana kuvhurika munhovo (yezvibatanidza, kufefetera, nezvimwewo) zvinogona kuderedza zvakanyanya kushanda kwayo.
• Grounding quality: Kudzika kwakaringana kwenhovo kwakakosha kudzivirira kuti isave antenna inopenya EMI pane kuivharira.

mhedziso

PCB kudzivirira chiitiko chakakosha mukugadzirwa kwemagetsi emazuva ano, kunyanya sezvo michina ichiramba ichidzikira uye kushanda pamhepo dzepamusoro. Matanho ekudzivirira akakodzera, anosanganisira kushandiswa kwesimbi dzakavharirwa, akamisikidzwa pasi akaturikidzana, uye nekungwarira PCB marongero, ndiwo kiyi yekuderedza kukanganiswa kwemagetsi uye kuve nechokwadi chekutevedzera EMC zviyero. Kusarudzwa kwezvinhu zvekudzivirira uye kuiswa kwayo mukati mekugadzira kunogona kukanganisa zvakanyanya kushanda uye kuvimbika kwechigadzirwa chekupedzisira.

KuHighleap Electronic, takazvipira kubatsira vatengi vedu kusangana nezvinetso izvi nepamusoro-soro, maPCB akagadzirwa nemazvo anobatanidza nzira dzekudzivirira dzepamusoro. Kugona kwedu mu-multi-layer uye HDI PCB kugadzira kunoita kuti titsigire zvaunonyanya kuda maapplication, kubva mumhepo uye masisitimu emotokari kuenda kuIoT uye zvemagetsi zvevatengi.

Bata Highleap Electronic nhasi kuti udzidze maitiro edu ePCB mhinduro anogona kukubatsira kukunda matambudziko eEMI uye kuwana hukuru hwepamusoro mumagadzirirwo ako.