Yintoni ububanzi bomgca?

Masiqale ngeziseko. Yintoni kanye kanye umkhondo wobubanzi? Kutheni le nto kubalulekile ukuba uchaze ububanzi bomkhondo othile? Injongo ye PCB Iingcingo kukudibanisa naluphi na uhlobo lwesiginali sombane (i-analog, idijithali okanye amandla) ukusuka kwenye indawo ukuya kwenye.

I-node inokuba sisikhonkwane secandelo, isebe lomkhondo omkhulu okanye inqwelomoya, okanye iphedi engenanto okanye indawo yovavanyo yokukhangela. Ububanzi bomkhondo buhlala bulinganiswa nge-mils okanye kumawakawaka ee-intshi. Ububanzi beentambo ezibanzi zemiqondiso yesiqhelo (akukho mfuno ikhethekileyo) inokuba zi-intshi ezininzi ubude kuluhlu lwee-7-12 mils, kodwa izinto ezininzi kufuneka ziqwalaselwe xa kuchazwa ububanzi beentambo nobude.

Isicelo siqhuba ububanzi beentambo kunye nohlobo lweentambo kuyilo lwePCB kwaye, ngaxa lithile, zihlala zilinganisa iindleko zokuvelisa zePCB, ubuninzi bebhodi / ubungakanani, kunye nokusebenza. Ukuba ibhodi ineemfuno ezithile zoyilo, ezinje ngesantya sokusebenza, ingxolo okanye uxinzelelo lokudibanisa, okanye umbane ophakamileyo / ombane, ububanzi kunye nohlobo lomkhondo lunokuba lubaluleke ngakumbi kunokwandisa iindleko zokuvelisa zePCB engenanto okanye ubungakanani bebhodi iyonke.

Inkcazo enxulumene nokufaka iintambo kwimveliso yePCB

Ngokwesiqhelo, ezi nkcukacha zilandelayo zinxulumene nokufaka iintambo kuqala ukunyusa iindleko zokuvelisa iiPCBS ezingenanto.

Ngenxa yonyamezelo oluqinileyo lwePCB kunye nezixhobo zokugqibela eziphezulu ezifunekayo kwimveliso, ukuhlolwa okanye ukuvavanywa kwePCBS, iindleko ziye ziphezulu kakhulu:

L Ububanzi bomkhondo bungaphantsi kwe-5 mil (0.005 in.)

L Treyisa isithuba esingaphantsi kweemitha ezintlanu

L Ngemingxunya engaphantsi kwe-8 mil ububanzi

L Trace ubukhulu obungaphantsi okanye obulinganayo kwi-ounce enye (ilingana ne-1 mils)

L Umahluko phakathi kwesibini kunye nobude obulawulweyo okanye ukungqinisisa kwe-wiring

Uyilo loxinano oluphezulu oludibanisa ukuthatha indawo kwePCB, ezinje ngeBGA enesithuba esihle okanye iibhasi ezihambelana nomqondiso ophezulu, kunokufuna ububanzi bomgca we-2.5 mil, kunye neendidi ezizodwa zemingxunya enqamlezileyo enobubanzi obufikelela kwi-6 mil, Njengoko laser yokomba microthrough-imingxunya. Kwelinye icala, ezinye zoyilo zamandla aphezulu zinokufuna iingcingo ezinkulu okanye iindiza, ukutya oonobumba bonke kunye nokugalela ii-ounces ezomeleleyo kunomgangatho. Kwisicelo esinyanzelwe sithuba, iipleyiti ezincinci kakhulu eziqulathe izaleko ezininzi kunye nobunzima obunqamlezileyo bokuphosa isiqingatha seyunce (0.7 mil ubukhulu) kunokufuneka.

Ngamanye amaxesha, uyilo lwesantya esiphezulu sonxibelelwano ukusuka kwelinye icala ukuya kwelinye kunokudinga iintambo kunye nokulawulwa okungafunekiyo kunye nobubanzi obuthile kunye nokushiyeka phakathi komnye nomnye ukunciphisa ukubonakaliswa kunye nokudibana okungahambelaniyo. Okanye uyilo lunokufuna ubude obuthile ukuze luhambelane neminye imiqondiso efanelekileyo ebhasi. Ukusetyenziswa kwamandla ombane aphezulu kufuna amanqaku okhuseleko, njengokunciphisa umgama phakathi kweempawu ezimbini ezahlukileyo zokuthintela ukurhangqa. Nokuba ziphi na iimpawu okanye amanqaku, ukulandelela iinkcazo kubalulekile, ke makhe sihlolisise usetyenziso olwahlukeneyo.

Ububanzi beentambo ezahlukeneyo kunye nobukhulu

Ii-PCBS ziqulathe iintlobo ezahlukeneyo zobubanzi belayini, njengoko zixhomekeke kwiimfuno zesiginali (jonga Umzobo 1). Ukulandelwa okuqaqambileyo okubonisiweyo kwenzelwe injongo ye-TTL (transistor-transistor logic) imiqondiso yenqanaba kwaye akukho mfuneko ikhethekileyo kukhuseleko oluphezulu lwangoku okanye lwengxolo.

Ezi ziya kuba zezona ntlobo zixhaphakileyo zeentambo ebhodini.

Ukuncipha kwe-wiring kulungiselelwe amandla okuphatha ngoku kwaye kunokusetyenziselwa iipheripherali okanye imisebenzi enxulumene namandla efuna amandla aphezulu, afana neefeni, iimoto, kunye nokudluliselwa kwamandla rhoqo kumacandelo amanqanaba asezantsi. Inxalenye ephezulu yasekhohlo yomzobo ikwabonisa uphawu lokwahlulahlula (isantya esiphezulu se-USB) esichaza isithuba kunye nobubanzi obuthile ukuhlangabezana neemfuno zempazamo ye-90 ω. Umzobo 2 ubonakalisa ibhodi yesekethe eshinyeneyo enamacandelo amathandathu kwaye ifuna iBGA (uluhlu lwebhola yegridi) indibano efuna ukubethelelwa kakuhle.

Uwabala njani ububanzi bomgca wePCB?

Masinyathele kwinkqubo yokubala ububanzi bokulandela umkhombandlela wamandla ogqithisela okwangoku ukusuka kwicandelo lamandla ukuya kwisixhobo esisecaleni. Kule mzekelo, siya kubala ubuncinci bomda wendlela yamandla emoto ye-DC. Indlela yamandla iqala kwifyuzi, inqumle iH-ibhulorho (icandelo elisetyenziselwa ukulawula ukuhanjiswa kwamandla kuwo onke amaza omoya e-DC), kwaye liphelisa kwisihlanganisi semoto. Umndilili oqhubekayo okhoyo ngoku ofunekayo kwimoto ye-DC umalunga ne-2 amperes.

Ngoku, i-PCB ye-wiring isebenza njenge-resistor, kwaye ngokude kunye nokunciphisa i-wiring, ukuxhathisa ngakumbi kuyongezwa. Ukuba i-wiring ayichazwanga ngokuchanekileyo, i-current yangoku ingonakalisa i-wiring kunye / okanye ibangele ukwehla kwamandla ombane kwimoto (okukhokelela kwisantya esincitshisiweyo). I-NetC21_2 eboniswe kuMzobo 3 imalunga nee-intshi ezi-0.8 ubude kwaye kufuneka ithwale ubuninzi bezibane ezi-2. Ukuba sithatha ezinye iimeko ngokubanzi, ezinje nge-1 ounce yokuthulula ithusi kunye nobushushu begumbi ngexesha lokusebenza okuqhelekileyo, kufuneka sibala ubuncinci bomgca wobubanzi kunye nokwehla koxinzelelo olulindelekileyo kububanzi.

Indlela yokubala ukuxhathisa kwe-PCB?

Le nxaki ilandelayo isetyenziselwa ukulandelela indawo:

Indawo [i-Mils ²] = (yangoku [Amps] / (K * (Temp_Rise [° C]) ^ b)) ^ (1 / C), elandela i-IPC yangaphandle (okanye phezulu / ezantsi) inqobo, k = 0.048, b = 0.44, C = 0.725. Qaphela ukuba ekuphela kwento ekufuneka siyifakile yeyangoku.

Sebenzisa lo mmandla kule nxaki ilandelayo kuya kusinika ububanzi obufunekayo obusixelela ububanzi bomgca obufunekayo ukuhambisa okwangoku ngaphandle kwengxaki ezinokubakho:

Ububanzi [Mils] = indawo [Mils ^ 2] / (ubukhulu [oz] * 1.378 [mils / oz]), apho i-1.378 inxulumene nomgangatho we-1 oz othulula ubukhulu.

Ngokufaka ii-amperes ezi-2 zangoku kubalo olungentla, sifumana ubuncinci be-30 mils ye-wiring.

Kodwa ayisixeleli ukuba ukwehla kwamandla ombane kuya kuba yintoni. Oku kubandakanyeka ngakumbi kuba kufuneka kubalwe ukunganyangeki ngocingo, okunokwenziwa ngokomgaqo oboniswe kumzobo 4.

Kule fomyula, ρ = ukumelana nobhedu, α = ubushushu bokulinganisa ubhedu, T = umkhondo wobukhulu, W = umkhondo wobubanzi, L = umkhondo wobude, T = ubushushu. Ukuba onke amaxabiso afanelekileyo afakwe kwi-0.8 “ubude be-30mils ububanzi, sifumanisa ukuba ukuxhathisa iintambo kumalunga ne-0.03? Kwaye yehlisa i-voltage malunga ne-26mV, efanelekileyo kwesi sicelo. Kuyanceda ukwazi ukuba yintoni echaphazela la maxabiso.

Isithuba sentambo se-PCB kunye nobude

Uyilo lwedijithali ngonxibelelwano olukhawulezayo, isithuba esithile kunye nobude obuhlengahlengisiweyo bunokufuneka ukunciphisa i-crosstalk, ukudibanisa, kunye nokubonisa. Ukulungiselela le njongo, ezinye iinkqubo eziqhelekileyo zisetyenziselwa ukwahluka kweempawu ezisekwe kwi-USB kunye nemiqondiso esekwe kwi-RAM ngokuhambelana. Ngokwesiqhelo, i-USB 2.0 iya kufuna umahluko okwi-480Mbit / s (iklasi yesantya esiphezulu se-USB) okanye ngaphezulu. Oku kungenxa yokuba isantya esiphezulu se-USB sisebenza kumanqanaba asezantsi kakhulu nakumahluko, ukuzisa inqanaba lomqondiso xa lilonke kufutshane nengxolo yangasemva.

Kukho izinto ezintathu ezibalulekileyo ekufuneka ziqwalaselwe xa uhambisa isantya esiphezulu seentambo ze-USB: ububanzi bocingo, isithuba sokukhokela, kunye nobude bekhebula.

Zonke ezi zinto zibalulekile, kodwa eyona nto ibaluleke kakhulu kwezi zintathu kukuqinisekisa ukuba ubude bemigca emibini buhambelana kakhulu. Njengomgaqo oqhelekileyo wesithupha, ukuba ubude beentambo buyahluka omnye komnye ngaphandle kwama-50 mils (ngesantya esiphezulu se-USB), oku kunyusa kakhulu umngcipheko wokubonakalisa, onokubangela unxibelelwano olubi. I-90 ohm yokulinganisa ukungahambelani yinkcazo ngokubanzi yokwahlulahlula iintambo ezimbini. Ukufezekisa le njongo, ukuhanjiswa kufuneka kulungiswe kububanzi kunye nokushiywa.

Umzobo 5 ubonakalisa umzekelo wesibini esahlukileyo sokufaka iintambo kwisantya esiphezulu se-USB eziqulathe i-12 mil ebanzi ye-wiring kwizithuba ezili-15 mil.

Ujongano lwezixhobo ezisekwe kwimemori eziqukethe ujongano olufanayo (njenge-DDR3-SDRAM) ziya kunyanzelwa ngakumbi kubude bocingo. Uninzi lwesoftware ye-PCB yesiphelo esiphakamileyo iya kuba nakho ukulungiswa kohlengahlengiso olwenza ukuba ubude bomgca buthelekise yonke imiqondiso efanelekileyo kwibhasi efanayo. Umzobo 6 ubonakalisa umzekelo woyilo lwe-DDR3 ngobude bohlengahlengiso lweentambo.

Imizila kunye neenqwelomoya zokugcwaliswa komhlaba

Ezinye izinto ezinezinto ezinengxolo, ezinje ngeetshipsi ezingenazingcingo okanye ii-eriyali, zinokufuna ukhuseleko olongezelelekileyo. Ukuyila i-wiring kunye neenqwelomoya ezinemingxunya yomhlaba efakwe ngaphakathi zinokukunceda kakhulu ekunciphiseni ukudityaniswa kweentambo ezikufuphi okanye ukuqokelela inqwelomoya kunye nemiqondiso yebhodi ekrwela kwimiphetho yebhodi.

Umzobo 7 ubonisa umzekelo wemodyuli yeBluetooth ebekwe kufutshane nomda wepleyiti, kunye ne-eriyali yayo (ngescreen esishicilelweyo “ANT” ukumakisha) ngaphandle komgca ongqindilili onemingxunya efakelweyo kwimingxunya edityaniswe kubume bomhlaba. Oku kunceda ukwahlula i-eriyali kwezinye iisekethe kunye neenqwelomoya.

Le ndlela yokwenza enye indlela yokuhamba ngomhlaba (kule meko inqwelomoya inqwelomoya) inokusetyenziselwa ukukhusela isekethe yebhodi kwisalali sangaphandle kwibhodi engenazingcingo. Umzobo 8 ubonakalisa i-PCB ethe-ethe ngengxolo kunye nenqwelomoya egxunyekwe ngaphakathi emngxunyeni webhodi.

Eyona ndlela isebenzayo ye-PCB ye-wiring

Zininzi izinto ezichonga iimpawu ze-wiring zentsimi ye-PCB, ke qiniseka ukuba ulandela ezona ndlela zilungileyo xa ufaka i-PCB yakho elandelayo, kwaye uya kufumana ibhalansi phakathi kweendleko ze-PCB, uxinano lwesekethe kunye nokusebenza ngokubanzi.