Iiphakheji ze-IC zixhomekeke PCB ukusasaza ubushushu. In general, PCB is the main cooling method for high power semiconductor devices. A good PCB heat dissipation design has a great impact, it can make the system run well, but also can bury the hidden danger of thermal accidents. 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. Many large semiconductor companies sell devices as standard components, and there is no contact between the manufacturer and the end application. Kule meko, sinokusebenzisa kuphela isikhokelo ngokubanzi ukunceda ukufezekisa isisombululo sokuhambisa ubushushu esingcono kwi-IC nakwinkqubo.

Uyila njani ukusasaza ubushushu kwePCB

Uhlobo lwephakheji yesiqhelo semiconductor alunanto okanye iphakheji yePowerPAD TM. In these packages, the chip is mounted on a metal plate called a chip pad. Olu hlobo lwepad chip luxhasa i-chip kwinkqubo yokulungiswa kwe-chip, kwaye ikwayindlela elungileyo yokufudumeza isixhobo sokutshisa ubushushu. When the packaged bare pad is welded to the PCB, heat is quickly exited from the package and into the PCB. The heat is then dissipated through the PCB layers into the surrounding air. 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. Care should be taken to separate temperature sensitive components from high power components on the 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. Izixhobo ezimbini ezifanayo zeemiconductor zibonisiwe: izinto A kunye no-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. For most applications today, the total volume of the system is shrinking, adversely affecting heat dissipation performance. Larger PCBS have more surface area that can be used for heat transfer, but also have more flexibility to leave enough space between high-power components.

Nanini na xa kunokwenzeka, ukwandisa inani kunye nobunzima bemihlaba yobhedu bePCB. Ubunzima bokumisa ubhedu ngokubanzi bukhulu, obuyindlela ebalaseleyo yokufudumeza ubushushu bokusasazeka kwe-PCB yonke. The arrangement of the wiring of the layers also increases the total specific gravity of copper used for heat conduction. 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. Different size of heat conduction plate has great influence on thermal performance. Iphepha ledatha yemveliso eliqulathiweyo ihlala idwelisa le milinganiselo. Kodwa ukulinganisa iimpembelelo zobhedu olongeziweyo kwi-PCBS yesiko kunzima. With online calculators, users can select a device and change the size of the copper pad to estimate its effect on the thermal performance of a non-JEDEC PCB. Ezi zixhobo zokubala ziqaqambisa ubungakanani bokuyilwa kwe-PCB nefuthe lomsebenzi wobushushu. For four-side packages, where the area of the top pad is just less than the bare pad area of the device, embedding or back layer is the first method to achieve better cooling. Kwiipakethi ezi-in-line ezimbini, sinokusebenzisa isitayile “sethambo lenja” ukusasaza ubushushu.

Okokugqibela, iinkqubo ezinePCBS ezinkulu zinokusetyenziselwa ukupholisa. The screws used to mount the PCB can also provide effective thermal access to the base of the system when connected to the thermal plate and ground layer. 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.