Kutheni le nto imigca ethe ethe kwi PCB imiphetho ethambekele kukuphazamiseka kwe-ESD?

Ukuseta inkqubo kwakhona kwenzeka xa kwavavanywa ibhentshi yomhlaba kusetyenziswa i-ESD yokunxibelelana nokukhupha i-6KV kwisiphelo sendlela. Ngexesha lovavanyo, iY capacitor eqhagamshelwe kwisiphelo somhlaba kunye nokusebenza kwedijithali yangaphakathi kwacinywa, kwaye iziphumo zovavanyo azikhange ziphuculwe.

Ukuphazamiseka kwe-ESD kungena kwisekethe yangaphakathi yemveliso ngeendlela ezahlukeneyo. Kwiimveliso ezivavanyiweyo kule meko, indawo yovavanyo yindawo esezantsi, uninzi lwe-ESD yokungenelela kwamandla iya kuhamba ukusuka kumgca wokumisa, oko kukuthi, i-ESD yangoku ayihambi ngokuthe ngqo kwisekethe yangaphakathi yemveliso, kodwa , kwi-IEC61000-4-2 esemgangathweni yovavanyo lwe-ESD kwesi sixhobo setafile, ubude bomgca wokulinganisa malunga ne-1m, Umgca wokumisa umhlaba uza kuvelisa i-inductance ekhokelayo enkulu (inokusetyenziselwa ukuqikelela u-1 u-H / m), ukuphazamiseka kokukhutshwa kombane kwenzeka (umzobo 1 wokutshintsha K) xa kuvaliwe, ukuphakama kwamaza aphezulu (ngaphantsi kwe-1 ns ukunyuka ecaleni kokukhutshwa kombane okwangoku yenza iimveliso ezivavanyiweyo zidibane ne-zero ombane wesiza (umzobo. 1 G ombane wenqaku ku-K ayiziro xa ivaliwe). Le volthi ingeyo-zero kwindawo yokuphela komhlaba iya kungena kwakhona kwisekethe yangaphakathi yemveliso. Umzobo 1 unike umzobo wokuphazamiseka kwe-ESD kwi-PCB ngaphakathi kwimveliso.

IKHIWANE. Umzobo we-1 weSchematic wokungenelela kwe-ESD kungena kwi-PCB ngaphakathi kwimveliso

Ingabonwa kwakhona ukusuka kumzobo 1 ukuba i-CP1 (i-parasitic capacitance phakathi kwe-discharge point kunye ne-GND), i-Cp2 (i-parasitic capacitance phakathi kwebhodi ye-PCB kunye nomgangatho wesalathiso somgangatho), umhlaba osebenzayo webhodi ye-PCB (GND) kunye nompu wokukhupha umbane (kubandakanya ucingo lomhlaba umphunga okhupha umbane) ngokudibeneyo zenza indlela yokuphazamiseka, kwaye ukuphazamiseka okwangoku yi-ICM. Kule ndlela yokungenelela, ibhodi ye-PCB isembindini, kwaye i-PCB ngokucacileyo iphazanyiswa kukukhutshwa kombane ngeli xesha. Ukuba kukho ezinye iintambo kwimveliso, ukuphazamiseka kuya kuba nzima ngakumbi.

Ngaba ukuphazamiseka kukhokelele njani ekusetyenzisweni ngokutsha kwemveliso evavanyiweyo? Emva kovavanyo olunononophelo lwe-PCB yemveliso evavanyiweyo, kwafumaniseka ukuba umgca wokulawula ukuseta kwakhona we-CPU kwi-PCB ubekwe kumda we-PCB nangaphandle kwendiza ye-GND, njengoko kubonisiwe kwi Umzobo 2.

Ukucacisa ukuba kutheni imigca eprintiweyo emaphethelweni e-PCB isengozini yokuphazamiseka, qala ngamandla e-parasitic phakathi kwemigca eprintiweyo kwi-PCB kunye nembasa yomhlaba. Kukho capacitance parasitic phakathi komgca eprintiweyo kunye nembasa isiseko ipleyiti, nto leyo eya kuphazamisa umgca uphawu eshicilelweyo kwibhodi PCB. Umzobo wesystem weendlela eziqhelekileyo zokuphazanyiswa kwamandla ombane ophazamisa umgca oprintiweyo kwi-PCB ubonisiwe kumzobo 3.

Umzobo 3 ubonakalisa ukuba xa ukuphazamiseka kwendlela eqhelekileyo (i-voltage-mode yokuphazamiseka kwendlela eqhelekileyo xa kuthelekiswa nomgangatho wokubonisa) ungena kwi-GND, i-voltage yokuphazamiseka iya kwenziwa phakathi komgca oshicilelweyo kwibhodi ye-PCB kunye ne-GND. Le volthi yokuphazanyiswa inxulumene kungekuphela kwempazamo phakathi komgca oshicilelweyo kunye ne-GND yebhodi yePCB (Z kumzobo 3) kodwa kunye nokubanakho kwesidudu esiphakathi komgca oshicilelweyo kunye nesalathiso somgangatho wepleyiti kwiPCB.

Ukuthatha ukuba i-impedance Z phakathi komgca oshicilelweyo kunye nebhodi ye-PCB ye-GND ayitshintshanga, xa amandla e-parasitic phakathi komgca oshicilelweyo kunye nomgangatho wokubhekisa umhlaba mkhulu, ukuphazamiseka kwevolthi phakathi komgca oshicilelweyo kunye nebhodi ye-PCB ye-GND inkulu. Lo mbane uphakanyiswe ngamandla ombane oqhelekileyo kwi-PCB kwaye uya kuchaphazela ngokuthe ngqo isekethe esebenzayo kwi-PCB.

IKHIWANE. 2 Okwenziweyo umzobo wenxalenye yePCB yocingo lwemveliso evavanyiweyo

IKHIWANE. I-3 yendlela yokuphazamiseka kwendlela yokuphazanyiswa kwamandla ombane we-PCB umzobo osikiweyo

Ngokwendlela 1 yokubala ubungakanani besidudu phakathi komgca oshicilelweyo kunye nesalathiso somhlaba, isinambuzane esisebenza phakathi komgca oshicilelweyo kunye nesalathiso somgangatho weplate luxhomekeke kumgama phakathi komgca oshicilelweyo kunye nesalathiso somhlaba (H kwiFomula 1) kunye nendawo elinganayo ebaleni lombane lwenziwa phakathi komgca oshicilelweyo kunye nesalathiso somhlaba

Ngokucacileyo, kuyilo lwesekethe kule meko, umgca wokubeka umda kwakhona kwi-PCB icwangciswe emaphethelweni ebhodi ye-PCB kwaye iwele ngaphandle kwenqwelomoya ye-GND, ke umgca womqondiso wokusetha kwakhona uya kuphazamiseka kakhulu, okukhokelela kwinkqubo yokuseta kwakhona ngexesha le-ESD vavanyo.