Kwizixhobo ze-elektroniki, umlinganiselo othile wokushisa uveliswa ngexesha lokusebenza, ukwenzela ukuba ukushisa kwangaphakathi kwezixhobo kukhuphuke ngokukhawuleza. Ukuba ubushushu abuchithwanga ngexesha, izixhobo ziya kuqhubeka zifudumala, kwaye isixhobo siya kusilela ngenxa yokushisa. Ukuthembeka kwezixhobo ze-elektroniki Ukusebenza kuya kuncipha.
Ngoko ke, kubaluleke kakhulu ukuqhuba unyango olufanelekileyo lokutshatyalaliswa kobushushu kwibhodi yesiphaluka. Ukutshatyalaliswa kobushushu bebhodi yesekethe ye-PCB likhonkco elibaluleke kakhulu, ngoko yintoni ubuchule bokutshatyalaliswa kobushushu bebhodi yesekethe ye-PCB, masiyixoxe kunye ngezantsi.
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Ukutshatyalaliswa kobushushu ngebhodi ye-PCB ngokwayo Iibhodi ze-PCB ezisetyenziswa ngoku ngokubanzi zi-copper clad/epoxy glasscloth substrates okanye i-phenolic resin glass substrates zelaphu, kunye nenani elincinci leebhodi zobhedu ezisekelwe ephepheni ziyasetyenziswa.
Nangona ezi substrates zineempawu ezigqwesileyo zombane kunye nepropathi yokusetyenzwa, zinokuphelisa ubushushu. Njengendlela yokuphelisa ubushushu kumacandelo aphezulu okufudumeza, akunakwenzeka ukuba ulindele ubushushu obuvela kwi-resin yePCB ngokwayo ukuqhuba ubushushu, kodwa ukuphelisa ubushushu obuvela kumphezulu wecandelo ukuya kumoya ojikelezayo.
Nangona kunjalo, njengoko iimveliso ze-elektroniki ziye zangena kwixesha le-miniaturization yamacandelo, ukunyuka kwe-high-density mounting, kunye ne-high-heating assembly, akwanelanga ukuthembela kumphezulu wecandelo kunye nommandla omncinci kakhulu wokukhupha ukushisa.
Kwangaxeshanye, ngenxa yokusetyenziswa ngokubanzi kwamacandelo okunyuka komhlaba afana ne-QFP kunye ne-BGA, ubushushu obuninzi obuveliswa ngamacandelo budluliselwa kwibhodi yePCB. Ngoko ke, eyona ndlela yokusombulula ingxaki yokutshatyalaliswa kobushushu kukuphucula amandla okutshatyalaliswa kobushushu be-PCB ngokwayo, edibana ngokuthe ngqo nento yokufudumeza, ngebhodi ye-PCB. Yenziwa okanye isasazwe.
Ngoko ke, kubaluleke kakhulu ukuqhuba unyango olufanelekileyo lokutshatyalaliswa kobushushu kwibhodi yesiphaluka. Ukutshatyalaliswa kobushushu bebhodi yesekethe ye-PCB likhonkco elibaluleke kakhulu, ngoko ke yintoni ubuchule bokutshatyalaliswa kobushushu bebhodi yesekethe ye-PCB, masiyixoxe kunye ngezantsi.
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Ukutshatyalaliswa kobushushu ngebhodi ye-PCB ngokwayo Iibhodi ze-PCB ezisetyenziswa ngoku ngokubanzi zi-copper clad/epoxy glasscloth substrates okanye i-phenolic resin glass substrates zelaphu, kunye nenani elincinci leebhodi zobhedu ezisekelwe ephepheni ziyasetyenziswa.
Nangona ezi substrates zineempawu ezigqwesileyo zombane kunye nepropathi yokusetyenzwa, zinokuphelisa ubushushu. Njengendlela yokuphelisa ubushushu kumacandelo aphezulu okufudumeza, akunakwenzeka ukuba ulindele ubushushu obuvela kwi-resin yePCB ngokwayo ukuqhuba ubushushu, kodwa ukuphelisa ubushushu obuvela kumphezulu wecandelo ukuya kumoya ojikelezayo.
Nangona kunjalo, njengoko iimveliso ze-elektroniki ziye zangena kwixesha le-miniaturization yamacandelo, ukunyuka kwe-high-density mounting, kunye ne-high-heating assembly, akwanelanga ukuthembela kumphezulu wecandelo kunye nommandla omncinci kakhulu wokukhupha ukushisa.
Kwangaxeshanye, ngenxa yokusetyenziswa ngokubanzi kwamacandelo okunyuka komhlaba afana ne-QFP kunye ne-BGA, ubushushu obuninzi obuveliswa ngamacandelo budluliselwa kwibhodi yePCB. Ngoko ke, eyona ndlela yokusombulula ingxaki yokutshatyalaliswa kobushushu kukuphucula amandla okutshatyalaliswa kobushushu be-PCB ngokwayo, edibana ngokuthe ngqo nento yokufudumeza, ngebhodi ye-PCB. Yenziwa okanye isasazwe.
Xa umoya uhamba, uhlala uhamba kwiindawo ezinokuxhatshazwa okuphantsi, ngoko xa ulungiselela izixhobo kwibhodi yesekethe eprintiweyo, gwema ukushiya indawo enkulu yomoya kwindawo ethile. Ukucwangciswa kweebhodi zeesekethe ezininzi eziprintiweyo kuwo wonke umatshini kufuneka kwakhona ingqalelo ingxaki efanayo.
Isixhobo esingeva ngamaqondo obushushu sibekwe ngcono kweyona ndawo isezantsi yobushushu (njengamazantsi esixhobo). Ungaze uyibeke ngqo phezu kwesixhobo sokufudumeza. Kungcono ukugxadazela izixhobo ezininzi kwinqwelomoya ethe tye.
Beka izixhobo ezinowona mandla aphezulu kunye nokuveliswa kobushushu kufutshane neyona ndawo ilungileyo yokulahla ubushushu. Musa ukubeka izixhobo zokufudumeza okuphezulu kwiikona kunye nemida ye-peripheral yebhodi eprintiweyo, ngaphandle kokuba i-heat sink ilungiselelwe kufuphi nayo.
Xa uyila i-resistor yamandla, khetha isixhobo esikhulu kangangoko kunokwenzeka, kwaye usenze sibe nesithuba esaneleyo sokutshatyalaliswa kobushushu xa uhlengahlengisa ukwakheka kwebhodi eprintiweyo.
Amacandelo aphezulu avelisa ubushushu kunye neeradiyetha kunye neepleyiti zokuqhuba ubushushu. Xa inani elincinci lamacandelo kwi-PCB livelisa ubushushu obukhulu (ngaphantsi kwe-3), isitya sokufudumala okanye umbhobho wokushisa unokongezwa kumacandelo okuvelisa ukushisa. Xa iqondo lobushushu lingenakwehliswa, linokusetyenziswa Iradiyetha enefeni ukongeza isiphumo sokuphelisa ubushushu.
Xa inani lezixhobo zokufudumeza likhulu (ngaphezu kwe-3), isigqubuthelo esikhulu sokutshatyalaliswa kobushushu (ibhodi) singasetyenziswa, esisitshi esikhethekileyo sokushisa esilungiselelwe ngokwendawo kunye nokuphakama kwesixhobo sokufudumeza kwi-PCB okanye i-flat enkulu. isinki yobushushu Sika iindawo ezahlukeneyo zobude becandelo. Isigqubuthelo sokutshatyalaliswa kobushushu sibotshwe ngokudibeneyo kumphezulu wecandelo, kwaye sidibanisa icandelo ngalinye ukutshabalalisa ubushushu.
Nangona kunjalo, umphumo wokutshatyalaliswa kobushushu awulungile ngenxa yokungahambi kakuhle kokuphakama ngexesha lokudibanisa kunye ne-welding yamacandelo. Ngokuqhelekileyo, isigaba esithambileyo sokutshintsha i-thermal pad yongezwa kumphezulu wecandelo ukuphucula umphumo wokutshatyalaliswa kobushushu.
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Kwizixhobo ezithatha ukupholisa umoya we-convection simahla, kungcono ukulungiselela iisekethe ezidibeneyo (okanye ezinye izixhobo) ngokuthe nkqo okanye ngokuthe tye.
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Yamkela uyilo locingo olufanelekileyo ukuqonda ukulahla ubushushu. Ngenxa yokuba i-resin kwipleyiti ine-conductivity ephantsi ye-thermal, kunye nemigca yefoyile yobhedu kunye nemingxuma yi-conductors yobushushu obuhle, ukwandisa izinga eliseleyo le-foil yobhedu kunye nokwandisa imingxuma yokuqhuba ubushushu zezona ndlela ziphambili zokutshatyalaliswa kobushushu. Ukuvavanya amandla okutshatyalaliswa kobushushu kwi-PCB, kuyimfuneko ukubala i-conductivity ye-thermal elinganayo (i-eq elithoba) yezinto ezidibeneyo ezenziwe ngezinto ezahlukeneyo kunye ne-thermal conductivity eyahlukileyo-i-substrate yokukhusela i-PCB.
Amacandelo akwibhodi eprintiweyo efanayo kufuneka acwangciswe ngokusemandleni ngokwexabiso le-calorific kunye neqondo lokutshatyalaliswa kobushushu. Izixhobo ezinexabiso eliphantsi le-calorific okanye ukunganyangeki kobushushu (ezifana ne-transistors encinci yesignali, iisekethe ezihlanganisiweyo ezincinci, i-electrolytic capacitors, njl. njl.) kufuneka zifakwe kwi-airflow yokupholisa. Ukuhamba okuphezulu (ekungeneni), izixhobo ezinokushisa okukhulu okanye ukumelana nobushushu (njengama-transistors amandla, iisekethe ezinkulu ezidibeneyo, njl.)
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Kwisalathiso esithe tye, izixhobo eziphezulu zamandla zilungiselelwe ngokusondeleyo kumda webhodi eprintiweyo ngokunokwenzeka ukunciphisa indlela yokudlulisa ukushisa; kwicala elithe nkqo, izixhobo eziphezulu zamandla zicwangciswe ngokusondeleyo kangangoko kunokwenzeka kumphezulu webhodi eprintiweyo ukunciphisa impembelelo yezi zixhobo kubushushu bezinye izixhobo. .
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Ukutshatyalaliswa kobushushu bebhodi eprintiweyo kwisixhobo ikakhulu kuxhomekeke ekuhambeni komoya, ngoko ke indlela yokuhamba komoya kufuneka ifundwe ngexesha loyilo, kwaye isixhobo okanye ibhodi yesekethe eprintiweyo kufuneka iqwalaselwe ngokufanelekileyo.
Xa umoya uhamba, uhlala uhamba kwiindawo ezinokuxhatshazwa okuphantsi, ngoko xa ulungiselela izixhobo kwibhodi yesekethe eprintiweyo, gwema ukushiya indawo enkulu yomoya kwindawo ethile.
Ukucwangciswa kweebhodi zeesekethe ezininzi eziprintiweyo kuwo wonke umatshini kufuneka kwakhona ingqalelo ingxaki efanayo.
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Isixhobo esingeva ngamaqondo obushushu sibekwe ngcono kweyona ndawo isezantsi yobushushu (njengamazantsi esixhobo). Ungaze uyibeke ngqo phezu kwesixhobo sokufudumeza. Kungcono ukugxadazela izixhobo ezininzi kwinqwelomoya ethe tye.
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Beka izixhobo ezinowona mandla aphezulu kunye nokuveliswa kobushushu kufutshane neyona ndawo ilungileyo yokulahla ubushushu. Musa ukubeka izixhobo zokufudumeza okuphezulu kwiikona kunye nemida ye-peripheral yebhodi eprintiweyo, ngaphandle kokuba i-heat sink ilungiselelwe kufuphi nayo. Xa uyila i-resistor yamandla, khetha isixhobo esikhulu kangangoko kunokwenzeka, kwaye usenze sibe nesithuba esaneleyo sokutshatyalaliswa kobushushu xa uhlengahlengisa ukwakheka kwebhodi eprintiweyo.