Kwiimeko ezininzi, PCB Iingcingo ziya kudlula kwimingxunya, iipads zovavanyo, imigca emifutshane yesikhondo, njl. Impembelelo ye-capacitance kwisiginali kufuneka ihlalutywe ukusuka esiphelweni sokuhambisa kunye nesiphelo sokufumana, kwaye inefuthe kwindawo yokuqala nasekupheleni.

Kuqala nqakraza ukubona ifuthe kulosasazo lomqondiso. Xa umqondiso wesantya esonyukayo ufikelela kwi-capacitor, i-capacitor ihlawuliswa ngokukhawuleza. Ukutshaja ngoku kuhambelana nokukhawuleza kwamandla ombane. Ifomula yokutshaja ngoku: I = C * dV / dt. Ukuphakama kwamandla, ukuphakama kokutshaja kwangoku, ngokukhawuleza ixesha lokunyuka komqondiso, i-dt encinci, ikwenyusa ukutshaja kwangoku.

Siyazi ukuba ukubonakaliswa komqondiso kunxulumene notshintsho kwimpedance yoluvo lweempawu, ke ngoko kuhlalutyo, masijonge kutshintsho lwe-impedance ebangelwa kukuqina kwamandla. Kwinqanaba lokuqala lokutshaja kwe-capacitor, impedance ibonakaliswa ngolu hlobo:

Apha, i-dV ngokwenyani lutshintsho lwevolthi yomqondiso wesinyathelo, dt lixesha lokunyuka komqondiso, kunye nefomula yempedance ye-capacitance iba:

Kule fomyula, sinokufumana ulwazi olubaluleke kakhulu, xa uphawu lwenyathelo lisetyenziswa kwinqanaba lokuqala kuzo zombini iziphelo ze-capacitor, i-impedance ye-capacitor inxulumene nexesha lokunyuka komqondiso kunye namandla alo.

Ngokwesiqhelo kwinqanaba lokuqala lokutshaja kwe-capacitor, i-impedance incinci kakhulu, incinci kune-impedance yolwakhiwo. Ukubonakaliswa okungalunganga kwesiginali kwenzeka kwi-capacitor, kwaye isignali yombane ongalunganga iphakanyiswe ngophawu lwantlandlolo, okukhokelela kukungathembeki komqondiso kumthumeli kunye non-monotonic yomqondiso kumthumeli.

Ukuphela kokufumana, emva kokuba umqondiso ufikelele esiphelweni sokufumana, ukubonakaliswa okuhle kuyenzeka, uphawu olubonakalisiweyo lufikelela kwisikhundla se-capacitor, olo hlobo lokuboniswa okungalunganga lwenzeka, kwaye umbane ongathandekiyo obonakalisa umva kwisiphelo sokufumana nawo ubangela umqondiso kulwamkelo end ukuvelisa ukuhla.

Ukuze ingxolo ebonakalisiweyo ibe ngaphantsi kwe-5% ye-voltage swing, enyamezelwayo ngumqondiso, utshintsho lwe-impedance kufuneka lube ngaphantsi kwe-10%. Ke kufanele ukuba yintoni ukungqinisisa kwe-capacitance? I-impedance ye-Capacitance yimpedance efanayo, kwaye sinokusebenzisa ifomula ye-impedance efanayo kunye nefomula yokulinganisa eyaneleyo yokujonga uluhlu lwayo. Kule mpazamo ifanayo, sifuna ukuba i-impedance ye-capacitance ibe nkulu kangangoko kunokwenzeka. Ukuthatha ukuba i-capacitance impedance ngamaxesha e-K ye-PCB ye-impedance yesimo, impedance evakalelwa ngumqondiso kwi-capacitor inokufunyanwa ngokungqinelana nefomula ye-impedance efanayo:

Oko kukuthi, ngokwale ndlela yokubala ifanelekileyo, i-impedance ye-capacitor kufuneka ubuncinci iphindaphindwe i-9 impedance yempawu ye-PCB. Ngapha koko, njengoko i-capacitor ihlawulisiwe, i-impedance ye-capacitor inyuka kwaye ayisoloko ihleli njenge-impedance esezantsi. Ukongeza, isixhobo ngasinye sinokunyanzelwa kwe-parasitic, eyonyusa i-impedance. Ke lo mda usithoba unokukhululeka. Kule ngxoxo ilandelayo, cinga ukuba umda uphindwe ka-5.

Ngesalathi se-impedance, sinokumisela ukuba yeyiphi i-capacitance enokunyamezelwa. Iimpawu ze-50 ohms kwibhodi yesekethe ziqheleke kakhulu, ke ndisebenzise i-50 ohms ukuyibala.

Kugqityiwe ekubeni:

Kule meko, ukuba ixesha lokunyuka komqondiso li-1ns, amandla angaphantsi kweepikogram ezi-4. Kwelinye icala, ukuba amandla e-picograms ama-4, ixesha lokunyuka komqondiso li-1ns ngokusemgangathweni. Ukuba ixesha lokunyuka komqondiso zii-0.5ns, ezi 4picograms capacitance ziya kubangela iingxaki.

Ukubala apha kukucacisa kuphela ifuthe lomthamo womsebenzi, isekethe eyiyo inzima kakhulu, izinto ezininzi kufuneka ziqwalaselwe, ke ukuba ukubalwa apha kuchanekile ayibalulekanga ngokubonakalayo. Isitshixo kukuqonda ukuba ingaba amandla ombane awuchaphazela njani umqondiso ngolu balo. Nje ukuba sibe nokuqonda okuqinisekileyo kwempembelelo yento nganye kwibhodi yesekethe, sinokunika isikhokelo esiyimfuneko kuyilo kwaye sazi indlela yokuhlalutya iingxaki xa zisenzeka. Uqikelelo oluchanekileyo ludinga ukulingiswa kwesoftware.

Isiphelo:

1. Umthwalo we-capacitive ngexesha le-PCB umzila ubangela ukuba umqondiso wokugqibela wokuhambisa uvelise ukuhla, kunye nomqondiso wokuphela komamkeli uya kuvelisa ukuhla.

2. Ukunyamezelana kokusebenza kwamandla kunxulumene nexesha lokunyuka komqondiso, ngokukhawuleza ixesha lokunyuka komqondiso, okuncinci ukunyamezelana kwamandla.