Sharp IV-C35M Manual de usuario descargar pdf (Pagina 14)

C35 Application Note



RoHS Compliant www.semileds.com

C35 Application Note V1.3

Subject to change without notice





Page

Thermalmanagement

Figure16.C35LEDL‐Icurve



Thermalresistance

Figure16showsacross‐sectionandasimplethermalmodelforaC35solderedontheMCPCB.Asimple

thermalmodelorthermalcircuitcanillustratetheheatflowingthroughaMCPCB.Heat

releasepathfrom

locationofheatgenerationforLEDchiptoambientisasbelow:

LEDchipDie‐attachresinceramicMCPCBAmbient

Where:

Tjisthetemperatureatthejunctionofthedevice

TcisthetemperatureattheCeramic

Tbisthetemperatureatthepoint

ofMCPCB

Taistheambientairtemperature

RjcisthethermalresistancefromjunctiontocaseoftheCeramic

RcbisthethermalresistancebetweenthecaseoftheCeramicandtheMCPCB

RbaisthermalresistancebetweenMC PCBandambient



Unitofthermalresistanceis

o

C/W,

Forexample,10Ԩ/Wmeansthattemperaturegoesup10Ԩpereveryinputpower1W.

Equation1belowrepresentstherelationshipbetweenTjandTa.



Tj=Ta+Rba×Pd+Rcb×Pd+Rjc×Pd

=Tb+Rcb×Pd+Rjc×Pd

=Tc+Rjc×Pd

Equation1



Inrealcase,itishardtomeasureTjdirectly,soitwillbeeasiertogettheTjbymeasuringTborTa.Then

theequation1canbesimplifiedtoequation2

1 2 ... 9 10 11 12 13 14 15 16 17 18

Sin comentarios

Sharp IV-C35M Manual de usuario Pagina 14