Iiphakheji ze-IC zixhomekeke PCB ukusasaza ubushushu. Ngokubanzi, i-PCB yeyona ndlela ipholileyo yokupholisa izixhobo ze-semiconductor zamandla aphezulu. Uyilo olulungileyo lokusasaza ubushushu lwe-PCB lunefuthe elikhulu, lunokwenza ukuba inkqubo iqhubeke kakuhle, kodwa ikwanokungcwaba ingozi efihliweyo yeengozi ezishushu. Ukuphatha ngononophelo kuyilo lwe-PCB, ubume bebhodi, kunye nokunyuka kwesixhobo kunokunceda ukuphucula ukusebenza kokutshatyalaliswa kobushushu kwizicelo eziphakathi kunye namandla amakhulu.

Abavelisi be-semiconductor banobunzima bokulawula iinkqubo ezisebenzisa izixhobo zazo. Nangona kunjalo, inkqubo ene-IC efakiweyo ibalulekile ekusebenzeni kwesixhobo ngokubanzi. Izixhobo ze-IC zesiko, inkqubo yoyilo isebenza ngokusondeleyo kunye nomenzi wayo ukuqinisekisa ukuba inkqubo iyahlangabezana neemfuno zokutshatyalaliswa kobushushu kwezixhobo ezinamandla aphezulu. Ukusebenzisana kwangoko kuqinisekisa ukuba i-IC iyahlangabezana nemigangatho yombane kunye nokusebenza, ngelixa iqinisekisa ukusebenza okukuko kwinkqubo yokupholisa umthengi. Iinkampani ezininzi ezinkulu zeemiconductor zithengisa izixhobo njengezinto ezisemgangathweni, kwaye akukho nxibelelwano phakathi komenzi kunye nesicelo sokugqibela. In this case, we can only use some general guidelines to help achieve a good passive heat dissipation solution for IC and system.

Uhlobo lwephakheji yesiqhelo semiconductor alunanto okanye iphakheji yePowerPAD TM. Kwezi phakheji, i-chip ibekwe kwityathanga lesinyithi elibizwa ngokuba yipad pad. Olu hlobo lwepad chip luxhasa i-chip kwinkqubo yokulungiswa kwe-chip, kwaye ikwayindlela elungileyo yokufudumeza isixhobo sokutshisa ubushushu. Xa iphedi engenanto ifakwe nge-welding kwi-PCB, kukhutshwa ubushushu ngokukhawuleza kwiphakheji kuye kwi-PCB. Ubushushu buye buchithwe ngeengqimba zePCB ukuya kumoya ojikelezileyo. Iiphakheji zeephedi eziqhelekileyo zidlulisela malunga neepesenti ezingama-80 zobushushu kwi-PCB ngapha ezantsi kwephakheji. Ama-20% aseleyo obushushu akhutshwa ziingcingo zeefowuni kunye namacala ahlukeneyo epakethe. Ngaphantsi kwe-1% yobushushu bubaleka ngaphezulu kwephakheji. Kwimeko yezi phakheji zingena-pad, uyilo olulungileyo lokusasaza ubushushu lwe-PCB lubalulekile ekuqinisekiseni ukusebenza kwesixhobo esithile.

Inxalenye yokuqala yoyilo lwe-PCB ephucula ukusebenza kwe-thermal uyilo lwesixhobo sePCB. Nanini na xa kunokwenzeka, izinto ezinamandla amakhulu kwi-PCB kufuneka zahlulwe enye kwenye. Esi sithuba somzimba phakathi kwezinto eziphezulu zamandla sokwandisa indawo yePCB ejikeleze icandelo ngalinye lamandla amakhulu, elinceda ukufezekisa ubushushu obungcono. Unonophelo kufuneka lwenziwe ukwahlula ubushushu kwizinto ezinobuzaza kumandla aphezulu kwi-PCB. Naphi na apho kufanelekileyo, izinto ezinamandla amakhulu kufuneka zibekwe kude nakwiikona zePCB. Indawo ekuyo iphakathi yePCB yandisa indawo yebhodi ejikeleze izinto ezinamandla amakhulu, ngaloo ndlela inceda ukuphelisa ubushushu. Figure 2 shows two identical semiconductor devices: components A and B. ICandelo A, elibekwe kwikona ye-PCB, linobushushu be-chip junction ye-5% ephezulu kunecandelo B, elibekwe ngaphezulu embindini. Ukutshatyalaliswa kobushushu kwikona yecandelo A kunqunyelwe yindawo encinci yephaneli ejikeleze icandelo elisetyenziselwa ukutshabalalisa ubushushu.

Inqaku lesibini kukuma kwePCB, enefuthe eligqibeleleyo ekusebenzeni kobushushu kuyilo lwePCB. Njengomgaqo ngokubanzi, ubhedu oluninzi lwe-PCB olunayo, kokukhona ukusebenza kokushisa kweenkqubo zenkqubo. Imeko efanelekileyo yokuchithwa kobushushu kwezixhobo ze-semiconductor kukuba i-chip ibekwe kwibloko enkulu yobhedu olupholileyo lulwelo. Oku akunakwenzeka kwizicelo ezininzi, ke kuye kwafuneka senze olunye utshintsho kwi-PCB ukuphucula ukutshatyalaliswa kobushushu. Uninzi lwezicelo namhlanje, inani elipheleleyo lenkqubo liyancipha, lichaphazela kakubi ukusebenza kobushushu. IiPCBS ezinkulu zinendawo engaphezulu enokusetyenziselwa ukuhambisa ubushushu, kodwa zikwanobhetyebhetye ngakumbi bokushiya indawo eyaneleyo phakathi kwezinto ezinamandla amakhulu.

Nanini na xa kunokwenzeka, ukwandisa inani kunye nobunzima bemihlaba yobhedu bePCB. Ubunzima bokumisa ubhedu ngokubanzi bukhulu, obuyindlela ebalaseleyo yokufudumeza ubushushu bokusasazeka kwe-PCB yonke. Ukulungelelaniswa kweentambo zomaleko kukonyusa ubukhulu bomxhuzulane obuthile obusetyenziselwa ukuhambisa ubushushu. Nangona kunjalo, le yocingo ihlala ifakelwe ngombane, ithintela ukusetyenziswa kwayo njengendawo yokufudumeza ubushushu. Isixhobo esisisiseko kufuneka sibethelelwe ngombane kangangoko kunokwenzeka kumaleko omhlaba omninzi kangangoko kunokwenzeka ukunceda ukwandisa ukuqhuba kobushushu. Imingxunya yokusasaza ubushushu kwi-PCB engezantsi kwesixhobo se-semiconductor inceda ubushushu bungene kwi-PCB kwaye idlulisele ngasemva kwebhodi.

Imigangatho ephezulu neyasezantsi ye-PCB “ziindawo eziphambili” zokuphucula ukusebenza kokupholisa. Sebenzisa iingcingo ezibanzi kunye nokuhamba kude nezixhobo ezinamandla aphezulu kunokubonelela ngeendlela zokufudumeza ubushushu. Ibhodi ekhethekileyo yokuhambisa ubushushu yindlela ebalaseleyo yokutshabalalisa ubushushu bePCB. Ipleyiti yokuhambisa ubushushu ibekwe phezulu okanye ngasemva kwi-PCB kwaye iqhagamshelwe ngokufudumeleyo kwisixhobo ngokusebenzisa uqhagamshelo lobhedu oluthe ngqo okanye umngxunya oshushu. Kwimeko yokupakisha emgceni (kuphela ngokukhokelela kumacala omabini epakethe), ipleyiti yokuhambisa ubushushu inokufumaneka ngaphezulu kwePCB, emile okwe “ithambo lenja” (umbindi umxinwa njengepakethe, ubhedu kude nepakethe unendawo enkulu, encinci embindini kwaye inkulu kuzo zombini iziphelo). Kwimeko yephakheji enamacala amane (kunye nezikhokelo kuwo omane amacala), ipleyiti yokuhambisa ubushushu kufuneka ibekwe ngasemva kwePCB okanye ngaphakathi kwePCB.

Ukunyusa ubungakanani bepleyiti yokuhambisa ubushushu yeyona ndlela ilungileyo yokuphucula ukusebenza kwe-thermal yeephakeji zePowerPAD. Ubungakanani obahlukileyo bepleyiti yokuhambisa ubushushu inefuthe elikhulu ekusebenzeni kobushushu. A tabular product data sheet typically lists these dimensions. Kodwa ukulinganisa iimpembelelo zobhedu olongeziweyo kwi-PCBS yesiko kunzima. Ngee-calculator ezikwi-intanethi, abasebenzisi banokukhetha isixhobo kwaye batshintshe ubungakanani bephedi yobhedu ukuqikelela ukusebenza kwayo kwi-thermal ye-non-JEDEC PCB. Ezi zixhobo zokubala ziqaqambisa ubungakanani bokuyilwa kwe-PCB nefuthe lomsebenzi wobushushu. Iiphakheji ezinamacala amane, apho indawo yephedi ephezulu ingaphantsi nje kwephedi engenanto yesixhobo, ukushumeka okanye umaleko wangasemva yindlela yokuqala yokufumana ukupholisa okungcono. Kwiipakethi ezi-in-line ezimbini, sinokusebenzisa isitayile “sethambo lenja” ukusasaza ubushushu.

Okokugqibela, iinkqubo ezinePCBS ezinkulu zinokusetyenziselwa ukupholisa. Izikere ezisetyenziselwa ukunyusa i-PCB zinokubonelela ngokufikelela ngokufudumeleyo kwisiseko senkqubo xa uqhagamshele kwipleyiti yokufudumeza kunye nongqameko lomhlaba. Ukuthathela ingqalelo ukuhanjiswa kwe-thermal kunye neendleko, inani lezikrufu kufuneka landisiwe ukuya kwinqanaba lokunciphisa imbuyekezo. Isinyanzelo se-PCB sentsimbi sinendawo yokupholisa ngakumbi emva kokuqhagamshelwa kwipleyiti eshushu. Kwezinye izicelo apho indlu ye-PCB inegobolondo, i-TYPE B ye-solder patch material inokusebenza okuphezulu kwe-thermal kuneqokobhe lomoya opholileyo. Izisombululo zokupholisa, ezinje ngeefeni kunye namaphiko, zihlala zisetyenziselwa ukupholisa inkqubo, kodwa zihlala zifuna indawo ethe kratya okanye zifuna uhlengahlengiso loyilo lokwandisa ukupholisa.

Ukuyila inkqubo enokusebenza okuphezulu kobushushu, akwanelanga ukukhetha isixhobo esifanelekileyo se-IC kunye nesisombululo esivaliweyo. Ukucwangciswa kokupholisa ukusebenza kwe-IC kuxhomekeke kwi-PCB kunye namandla enkqubo yokupholisa ukuvumela izixhobo ze-IC ukuba zipholile ngokukhawuleza. Indlela epholileyo yokupholisa ekhankanywe apha ngasentla inokuphucula kakhulu ukusebenza kobushushu kwinkqubo.