Cov pob IC vam khom PCB rau tshav kub dissipation. In general, PCB is the main cooling method for high power semiconductor devices. Kev tsim hluav taws xob PCB kom sov zoo muaj qhov cuam tshuam zoo, nws tuaj yeem ua rau lub kaw lus ua haujlwm tau zoo, tab sis kuj tuaj yeem faus qhov phom sij ntawm kev raug cua sov. Ua tib zoo saib xyuas PCB txheej txheem, txheej txheem pawg thawj coj, thiab cov cuab yeej sib txuas tuaj yeem pab txhim kho kev ua kom sov cua sov rau nruab nrab-thiab daim ntawv thov siv hluav taws xob siab.

Cov tuam txhab tsim hluav taws xob muaj teeb meem tswj hwm cov txheej txheem uas siv lawv cov khoom siv. Txawm li cas los xij, lub kaw lus nrog IC teeb tsa yog qhov tseem ceeb rau kev ua tau zoo ntawm lub cuab yeej. Txog kev cai IC cov cuab yeej, tus tsim qauv tsim feem ntau ua haujlwm ze nrog cov chaw tsim khoom kom ntseeg tau tias lub kaw lus ua tau raws li ntau qhov xav tau cua sov ntawm cov khoom siv hluav taws xob siab. Qhov kev koom tes thaum ntxov no ua kom ntseeg tau tias IC ua tau raws cov qauv siv hluav taws xob thiab ua tau zoo, thaum ua kom ntseeg tau tias ua haujlwm tau zoo hauv cov neeg siv khoom cua txias. Many large semiconductor companies sell devices as standard components, and there is no contact between the manufacturer and the end application. Hauv qhov no, peb tsuas tuaj yeem siv qee cov lus qhia dav dav txhawm rau pab ua kom tau zoo dua qhov ua kom sov cua sov daws rau IC thiab cov kab ke.

Yuav ua li cas tsim kom muaj cua sov rau PCB

Hom pob khoom siv hluav taws xob ib txwm yog lub ncoo ncoo lossis pob PowerPADTM. In these packages, the chip is mounted on a metal plate called a chip pad. Hom kab ntawv no txhawb nqa cov nti hauv cov txheej txheem txheej txheem, thiab tseem yog txoj hauv kev zoo rau cov khoom siv cua sov ua kom sov. 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. Cov pob ntawv tsis tshua muaj feem ntau xa tawm txog 80% ntawm tshav kub mus rau hauv PCB los hauv qab ntawm pob. Qhov seem 20% ntawm tshav kub tau tso tawm los ntawm cov xov hlau thiab ntau sab ntawm pob. Tsawg dua 1% ntawm cov cua sov khiav hla lub pob saum toj. Nyob rau hauv cov ntaub ntawv ntawm cov pob-liab qab no, cov PCB tsim hluav taws xob tsim hluav taws xob zoo yog qhov tseem ceeb kom ntseeg tau qee yam khoom siv tau zoo.

Thawj qhov ntawm PCB tsim uas txhim kho kev ua haujlwm tau zoo yog PCB cov cuab yeej teeb tsa. Thaum ua tau, cov khoom siv hluav taws xob siab ntawm PCB yuav tsum sib cais los ntawm ib leeg. Qhov kev sib txawv ntawm lub cev nruab nrab ntawm cov khoom siv hluav taws xob siab tshaj plaws hauv cheeb tsam PCB nyob ib ncig ntawm txhua qhov kev siv hluav taws xob siab, uas pab ua kom sov zoo dua. Kev saib xyuas yuav tsum tau ua kom cais cov khoom tiv thaiv kub los ntawm cov khoom siv hluav taws xob siab ntawm PCB. Txhua qhov ua tau, cov khoom siv hluav taws xob siab yuav tsum nyob deb ntawm cov ces kaum ntawm PCB. A more intermediate PCB position maximizes the board area around the high-power components, thereby helping to dissipate heat. Ob yam khoom siv hluav taws xob zoo ib yam tau pom: cov khoom A thiab B. Cheeb Tsam A, nyob ntawm lub ces kaum ntawm PCB, muaj A chip hlws ris kub 5% siab dua tivthaiv B, uas yog nyob rau hauv nruab nrab ntau dua. Cov cua sov ua kom sov ntawm lub ces kaum ntawm kev tivthaiv A yog txwv los ntawm thaj chaw me me nyob ib puag ncig tivthaiv siv rau kev ua kom sov.

Qhov thib ob yog tus qauv ntawm PCB, uas muaj kev txiav txim siab tshaj plaws rau kev ua haujlwm kub ntawm PCB tsim. Raws li txoj cai dav dav, ntau tooj liab PCB muaj, ntau dua cov cua sov ua haujlwm ntawm cov txheej txheem txheej txheem. Qhov xwm txheej cua sov zoo tshaj plaws rau cov khoom siv hluav taws xob yog tias lub nti tau teeb tsa ntawm ib qho loj ntawm cov kua txias txias. This is not practical for most applications, so we had to make other changes to the PCB to improve heat dissipation. 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.

Thaum twg los xij, ua kom muaj tus lej thiab tuab ntawm PCB txheej tooj liab. Qhov hnyav ntawm cov tooj liab hauv av feem ntau yog qhov loj, uas yog ib txoj hauv kev zoo tshaj plaws rau tag nrho cov cua sov PCB tawg. The arrangement of the wiring of the layers also increases the total specific gravity of copper used for heat conduction. Txawm li cas los xij, cov xov hluav taws xob no feem ntau yog hluav taws xob tiv thaiv, txwv nws txoj kev siv ua lub dab dej kub. Cov cuab yeej hauv av yuav tsum tau siv hluav taws xob ntau li ntau tau kom ntau txheej hauv av kom ntau li ntau tau kom pab ua kom sov sov ntau dua. Cov cua sov tso tawm qhov hauv PCB hauv qab cov cuab yeej siv hluav taws xob pab cua sov nkag mus rau txheej txheej ntawm PCB thiab hloov mus rau tom qab ntawm lub rooj tsavxwm.

Cov txheej saum toj thiab hauv qab ntawm PCB yog “thaj chaw tseem ceeb” rau kev ua kom txias txias. Kev siv cov xov hluav taws xob dav dua thiab kev khiav deb ntawm cov cuab yeej siv hluav taws xob muaj peev xwm muab txoj hauv kev rau cua sov kom sov. Lub rooj tsav xwm tshwj xeeb ua kom sov yog ib txoj hauv kev zoo rau PCB cov cua sov ua kom sov. Cov phaj ua kom sov yog nyob rau sab saum toj lossis sab nraub qaum ntawm PCB thiab tau txuas nrog cua sov mus rau lub cuab yeej los ntawm kev txuas ncaj qha tooj liab lossis cua sov los ntawm qhov. Nyob rau hauv cov ntaub ntawv ntim hauv kab (tsuas yog ua rau ob sab ntawm pob ntawv), cov cua sov phaj tuaj yeem nyob rau sab saum toj ntawm PCB, zoo li “pob txha dev” (nruab nrab yog nqaim li pob, tooj liab nyob deb ntawm pob ntawv muaj thaj tsam loj, me nyob hauv nruab nrab thiab loj ntawm ob qho kawg). Nyob rau hauv cov ntaub ntawv ntawm plaub-sab pob (nrog cov coj ntawm txhua plaub sab), cov phaj ua kom sov yuav tsum nyob rau sab nraum qab ntawm PCB lossis sab hauv PCB.

Ua kom qhov loj ntawm cov phaj ua kom sov yog ib txoj hauv kev zoo los txhim kho cov cua sov ua haujlwm ntawm PowerPAD pob. Different size of heat conduction plate has great influence on thermal performance. Daim ntawv cov khoom lag luam cov ntaub ntawv feem ntau teev cov qhov ntev no. Tab sis ntsuas qhov cuam tshuam ntawm ntxiv tooj liab ntawm kev cai PCBS nyuaj. 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. Cov cuab yeej suav no hais txog qhov uas PCB tsim muaj feem cuam tshuam rau kev ua kom sov sov. 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. Rau ob kab hauv kab, peb tuaj yeem siv “pob txha dev” pad style los ua kom sov sov.

Thaum kawg, cov tshuab nrog PCBS loj dua tuaj yeem siv tau rau txias. 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. Xav txog kev ua kom muaj cua sov thiab tus nqi, tus naj npawb ntawm cov ntsia hlau yuav tsum tau ua kom siab tshaj plaws kom txo qis rov qab los. Cov hlau khov PCB muaj thaj tsam txias ntau dua tom qab txuas nrog cov phaj cua sov. Rau qee daim ntawv thov uas PCB tsev nyob muaj lub plhaub, TYPE B cov khoom siv thaj ua rau thaj muaj cov cua sov zoo dua li lub plhaub cua txias. Kev daws cua txias, xws li kiv cua thiab fins, kuj tseem siv rau qhov cua txias, tab sis lawv feem ntau xav tau chaw ntau dua lossis xav tau kev hloov kho kom ua kom zoo dua qub.

Txhawm rau tsim lub kaw lus nrog kev ua haujlwm siab cua sov, nws tsis txaus los xaiv lub cuab yeej IC zoo thiab kaw kev daws teeb meem. IC lub sijhawm ua haujlwm txias yog nyob ntawm TUS PCB thiab lub peev xwm ntawm lub tshuab txias kom tso cai rau IC cov cuab yeej kom txias sai. Txoj kev txias txias uas tau hais los saum no tuaj yeem txhim kho kev ua kom sov cua sov ntawm lub cev.