Dab tsi yog cov qauv tsim thermal ntawm diodes hauv cov cuab yeej kho mob PCBs?

1, Kev xaiv cov khoom siv: Sib npaug qis thermal kuj thiab siab thermal conductivity
Cov cuab yeej kho mob muaj qhov kub thiab txias, xws li cov khoom siv cog qoob loo uas yuav tsum tau ua raws li tib neeg cov ntaub so ntswg sib raug zoo (ISO 10993 tus qauv) thiab ua haujlwm ruaj khov nyob rau hauv qhov kub thiab txias ntawm 37℃rau lub sijhawm ntev. Kev xaiv cov khoom ntim diode yuav tsum coj mus rau hauv tus account ob qho tib si thermal kuj thiab hluav taws xob ua haujlwm:

Cov khoom siv hluav taws xob qis rau pem hauv ntej: Schottky diodes (xws li BAT62-02V) nyiam, nrog rau pem hauv ntej voltage poob (Vf) tsawg li 0.25V @ 10mA Piv rau cov tsoos silicon diodes (0.6V ~ 0.7V), nws txo lub zog siv ntau dua 60%. Nyob rau hauv lub wireless kis tau tus mob module ntawm CGM li, tsawg Vf yuav txo tau cov conduction poob ntawm lub RF pem hauv ntej-kawg Circuit Court thiab txuas mus rau ib tug xwb nqi ntau yam.
Kev ntim cov thermal conductivity siab: Rau siab - lub zog diodes (xws li IGBT diodes ntim hauv TO-247), hlau substrates (xws li txhuas substrates) lossis tooj liab thaiv tshuab yuav tsum tau siv. Lub thermal conductivity ntawm aluminium substrate ncav cuag 2W / m · K, uas yog 6 lub sij hawm siab tshaj ntawm FR-4 board (0.3W / m · K), thiab tuaj yeem ua qhov kub thiab txias ntawm lub diode rau saum npoo ntawm PCB.
Cov ntaub ntawv kub resistant: Cov khoom siv kho mob yuav tsum tau ua kom tsis muaj menyuam thaum qhov kub thiab txias (xws li 121℃chav sterilization), thiab cov khoom ntim diode yuav tsum tau ua kom tau raws li qhov kub thiab txias. Piv txwv li, kev lag luam qib Schottky diodes (xws li SS54) tuaj yeem tiv taus qhov kub ntawm -55℃txog 150 degree, zam kev sib koom ua ke tawg los ntawm kev sib txuam thermal expansion coefficients thaum tua kab mob.
2, Layout optimization: txo qhov kub qhov concentration thiab airflow obstruction
Cov khoom siv kho mob PCBs feem ntau yog compact nyob rau hauv qhov chaw, thiab lub diode layout yuav tsum tau ua raws li lub hauv paus ntsiab lus ntawm "dispersing tshav kub qhov chaw thiab optimizing cua ducts":

Kev faib tawm ntawm cov khoom siv hluav taws xob: Lub zog hluav taws xob diodes yuav tsum tau muab sib npaug ntawm PCB kom tsis txhob muaj kev tso siab ntau uas yuav ua rau muaj qhov kub ntxhov hauv zos. Piv txwv li, nyob rau hauv lub hwj chim module ntawm lub portable ultrasound diagnostic ntaus ntawv, rectifier diodes raug faib raws ntug ntawm lub PCB, siv tej yam ntuj tso convection rau tshav kub dissipation, uas ua rau ib tug 15℃txo nyob rau hauv junction kub piv rau ib tug centralized layout.
Kev ntsuas kub ntawm cov cuab yeej sib cais: Cov ntsuas kub ntawm cov khoom xws li electrolytic capacitors yuav tsum tau khaws cia kom deb ntawm diode tshav kub. Nyob rau hauv huab cua- txias txias, qhov kev ncua deb ntawm ob yuav tsum siab tshaj los yog sib npaug rau 2.5 hli; nyob rau hauv tej yam ntuj tso cua txias, qhov kev ncua deb yuav tsum ntau tshaj los yog sib npaug zos rau 4.0mm. Yog tias qhov chaw muaj tsawg, cov hluav taws xob hluav taws xob tuaj yeem raug cais tawm los ntawm lub tshav kub tiv thaiv phaj (xws li 0.5mm tuab tooj liab phaj).
Airflow guidance design: Rau cov khoom siv cua txias (xws li cov saib siv hauv chav ua haujlwm), diodes yuav tsum tau muab tso rau hauv qab ntawm cov cua nkag los yog sab saud ntawm lub qhov hluav taws xob los xyuas kom meej tias cov cua ntws ncaj qha npog cov cua sov. Piv txwv li, tso rectifier diodes ncaj qha tom qab lub kiv cua txias tuaj yeem ua rau kom cua nrawm nrawm los ntawm 30% thiab txo cov cua sov los ntawm 20%.
3, Thaum tshav kub kub dissipation txhim khu kev qha: kev tsim kho ntawm ntau -theem tshav kub conduction paths
Cov khoom siv kho mob PCBs xav tau peb -theem cua sov dissipation system ntawm "Device PCB Heat Sink" kom ua tiav kev tswj xyuas thermal:

Tus ntaus ntawv theem tshav kub dissipation:
Tsim cov khoom siv hluav taws xob hluav taws xob: TO-247 ntim diodes yuav tsum muaj thaj tsam loj ntawm cov cua sov dissipation pads (txuas nruab nrab pins) tsim los rau pem hauv ntej ntawm PCB, thiab thaj tsam loj ntawm cov khoom siv hluav taws xob tooj liab (xws li 10mm × 10mm) tsim rau sab nraub qaum. Pem hauv ntej thiab nram qab tooj liab foils yuav tsum tau txuas nrog ntom ntom thermal conductive vias (xws li 10 × 10 array nrog ib txoj kab uas hla ntawm 0.3mm). Thermal conductive vias yuav tsum tau ntim nrog cov khoom siv hluav taws xob (xws li nyiaj muab tshuaj txhuam) thiab npog nrog daim npog ntsej muag kom txo tau qhov kev tiv thaiv thermal.
Sab nraud lub dab dej kub: Nruab ib lub dab dej kub finned (xws li 60mm × 60mm aluminium heat sink) ntawm lub tshav kub dissipation ncoo nyob rau sab nraum qab ntawm PCB, thiab sau qhov sib chwv qhov sib txawv nrog thermal conductive silicone roj (thermal conductivity 5W / m · K) kom ntseeg tau tias qhov sib txuas kub yog txo los ntawm ntau tshaj 30℃tsis muaj cua sov.
PCB theem kub dissipation:
Cov ntawv ci tooj liab thiab ntau lub rooj tsav xwm: Siv PCB nrog ntau dua lossis sib npaug ntawm 2oz (70 μ m) tooj liab thickness, thiab txawm siv 3oz tooj liab thickness lossis hlau substrate. Rau cov xwm txheej muaj zog heev, cov tooj liab blocks (xws li 5 hli tuab tooj liab blocks) tuaj yeem muab tso rau hauv PCB kom ncaj qha hu rau diode heat dissipation pads, ua tiav cov ntsiab lus zoo - mus rau - taw tes thaum tshav kub kub conduction.
Thaum tshav kub kub dissipation los ntawm lub qhov thiab qhov muag tsis pom qhov: Tsim cov cua kub dissipation los ntawm qhov (Nyob rau hauv Pad, VIPPO) nyob ib ncig ntawm lub diode, sau lawv nrog resin los yog cov ntaub ntawv conductive, thiab npog lawv nrog solder daim npog qhov ncauj kom lub tshav kub dissipation cheeb tsam. Piv txwv li, kev teeb tsa ntawm qhov ntawm LCCC cov ntaub qhwv tuaj yeem ua kom cov thermal conductivity nce 50%.
System theem tshav kub dissipation:
Natural convection optimization: Thaum siv tej yam ntuj tso convection rau hloov tshav kub, qhov ntev ntawm lub tshav kub dissipation fins yuav tsum tau perpendicular mus rau hauv av, siv lub nce nyhuv ntawm cov cua kub los txhim kho cov cua kub dissipation. Piv txwv li, kev txhim kho cov fins ntawm lub diode cua sov dab dej vertically tuaj yeem txo cov thermal resistance los ntawm 15% piv rau kab rov tav installation.
Forced air cooling synergy: Thaum siv cov cua txias kom dissipate cua sov, cov kev taw qhia ntawm lub radiator fins yuav tsum tau ua raws li cov kev taw qhia ntawm airflow kom tsis txhob upstream radiator diversion ntawm airflow. Piv txwv li, nyob rau hauv cov kev taw qhia ntawm huab cua ncig, siv staggered kev npaj ntawm radiators los yog staggered fins yuav ua rau kom lub nto cua ceev ntawm downstream radiators los ntawm 20%.
4, Kev lees paub tseeb: tag nrho cov txheej txheem tswj los ntawm simulation mus rau qhov kev sim tiag
Cov cuab yeej kho mob yuav tsum tau xeem dhau qhov kev ntsuas ib puag ncig nruj (xws li IEC 60601-1 tus qauv), thiab diode thermal tsim yuav tsum tau kuaj xyuas los ntawm kev simulation thiab kev sim tiag tiag:

Kev ntsuas cua kub simulation: Siv software xws li ANSYS Icepak lossis Flotherm los tsim ib qho peb - qauv thermal ntawm PCB, simulate lub diode hlws ris kub, PCB kub faib, thiab airflow teb. Piv txwv li, los ntawm kev simulating thiab optimizing PCB layout ntawm ib tug implanted ntaus ntawv, lub diode hlws ris kub yuav txo tau los ntawm 125℃mus rau 105 degree, ua tau raws li qhov ntev - lub sij hawm cog kev ruaj ntseg.
Kev ntsuas qhov ntsuas kub nce siab: Hauv kev ntsuas kub thiab av noo (xws li -40℃~ 85 degree, 1000 cycles), siv cov duab hluav taws xob infrared los saib xyuas qhov kub thiab txias ntawm diode, kom ntseeg tau tias qhov kub nce qis dua lossis sib npaug li 10℃(tus nqi raug). Piv txwv li, cov cuab yeej CGM tau sim nyob rau hauv qhov kub thiab txias ib puag ncig, thiab qhov sib txawv ntawm diode saum npoo ntawm qhov ntsuas kub ntawm qhov simulation tau tsawg dua los yog sib npaug li 2 degree, uas tau txheeb xyuas qhov tseeb ntawm cov thermal tsim.
Lub sij hawm ntev kev ntseeg siab acceleration xeem: Ntsuas qhov kev ntseeg siab ntawm diode solder pob qij txha los ntawm siab - kub aging (xws li 125℃, 1000 teev) thiab kev vibration testing (xws li 10-2000Hz, 5g vibration). Piv txwv li, kev ntsuam xyuas kev vibration tau ua rau ntawm BGA ntim diodes uas muaj cov nplaum nplaum, thiab cov pob qij txha tsis pom qhov tawg, ua tau raws li 10 xyoo kev pabcuam lub neej ntawm cov khoom siv kho mob.