天津职业技术师范大学2015届本科毕业设计EmbeddedProcessorBasedAutomaticTemperatureControlofVLSIChipsAbstractThispaperpresentsembeddedprocessorbasedautomatictemperaturecontrolofVLSIchips,usingtemperaturesensorLM35andARMprocessorLPC2378.Duetotheveryhighpackingdensity,VLSIchipsgetheatedverysoonandifnotcooledproperly,theperformanceisverymuchaffected.Inthepresentwork,thesensorwhichiskeptverynearproximitytotheICwillsensethetemperatureandthespeedofthefanarrangedneartotheICiscontrolledbasedonthePWMsignalgeneratedbytheARMprocessor.Abuzzerisalsoprovidedwiththehardware,toindicateeitherthefailureofthefanoroverheatingoftheIC.TheentireprocessisachievedbydevelopingasuitableembeddedCprogram.Keywords:Temperaturesensor,ARMprocessor,VLSIchips,BrushlessDCmotor1.IntroductionWiththephenomenaldevelopmentsinVLSItechnology,theambitiousICdesignersaretryingtoputmoretransistorsintosmallerpackages.So,theICsrunathigherspeedsandproducelargeamountofheatwhichcreatestheproblemofthermalmanagement.Forexample,nowadaystheCPUchipsarebecomingsmallerandsmallerwithalmostnoroomfortheheattoescape.Thetotalpowerdissipationlevelsnowresideontheorderof100Wwithapeakpowerdensityof400-500W/Cm2,andarestillsteadilyclimbing.Asthechiptemperatureincreasesitsperformanceisverymuchdegradedbyparametersshift,decreaseinoperatingfrequenciesandout-ofspecificationoftimings.Sothehighspeedchipsmustbecooledtomaintaingoodperformanceforthelongestpossibleoperatingtimeandoverthewidestpossiblerangeofenvironmentalconditions.Themaximumallowabletemperatureforahighspeedchiptomeetitsparametricspecificationsdependsontheprocessandhowthechipisdesigned.Amongthevariouscoolingtechniques,heatsinks,heatpipes,fansandclockthrottlingareusuallyemployed.Amongthesetechniques,fanscandramaticallyreducethetemperatureofahighspeedchip,buttheyalsogenerateagreatdealofacousticnoise.Thisnoisecanbereducedsignificantlybyvarying,thefansspeedbasedontemperaturei.e.thefancanturnslowlywhenthetemperatureislowandcanspeedupasthetemperatureincreases.Theotherprominentmethodis