 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
LTC3541EDD-1-PBF Datasheet(PDF) 9 Page - Linear Technology |
|
||||||||||||||||||||||||||||||
LTC3541EDD-1-PBF Datasheet(HTML) 9 Page - Linear Technology |
|
|
9 / 20 page  LTC3541-1 35411fa OPERATIO buckregulatorwithouttheneedforexternalpincontrol. AdetaileddiscussionofthetransitionsbetweentheVLDO and linear regulator can be found in the VLDO/Linear RegulatorLoopsection. Buck Regulator Control Loop TheLTC3541-1internalbuckregulatorusesaconstant frequency,currentmode,step-downarchitecture.Boththe main(top,P-channelMOSFET)andsynchronous(bottom, N-channelMOSFET)switchesareinternal.Duringnormal operation,theinternalmainswitchisturnedonatthebe- ginningofeachclockcycleprovidedtheinternalfeedback voltagetothebuckislessthanthereferencevoltage.The currentintotheinductorprovidedtotheloadincreases untilthecurrentlimitisreached.Oncethecurrentlimitis reachedthemainswitchturnsoffandtheenergystored intheinductorflowsthroughthebottomsynchronous switchintotheloaduntilthenextclockcycle. Thepeakinductorcurrentisdeterminedbycomparingthe buckfeedbacksignaltoaninternal0.8Vreference.When theloadcurrentincreases,theoutputofthebuckand hencethebuckfeedbacksignaldecrease.Thisdecrease causesthepeakinductorcurrenttoincreaseuntiltheaver- ageinductorcurrentmatchestheloadcurrent.Whilethe mainswitchisoff,thesynchronousswitchisturnedon untileithertheinductorcurrentstartstoreversedirection orthebeginningofanewclockcycle. WhentheMODEpinisdriventoalogiclow,theLTC3541-1 buckregulatoroperatesinBurstModeoperationforhigh efficiency.Inthismode,themainswitchoperatesbased upon load demand. In Burst Mode operation the peak inductorcurrentissettoafixedvalue,whereeachburst eventcanlastfromafewclockcyclesatlightloadsto nearly continuous cycling at moderate loads. Between bursteventsthemainswitchandanyunneededcircuitry areturnedoff,reducingthequiescentcurrent.Inthissleep state,theloadisbeingsuppliedsolelyfromtheoutput capacitor.Astheoutputvoltagedroops,aninternalerror amplifier’soutputrisesuntilawakethresholdisreached causingthemainswitchtoagainturnon.Thisprocess repeatsataratethatisdependantupontheloadcurrent demand. WhentheMODEpinisdriventoalogichightheLTC3541-1 operatesinPulse-Skipmodeforlowoutputvoltageripple. In this mode, the LTC3541-1 continues to switch at a constantfrequencydowntoverylowcurrents,whereit willbeginskippingpulsesusedtocontrolthemain(top) switchtomaintaintheproperaverageinductorcurrent. Iftheinputsupplyvoltageisdecreasedtoavalueap- proachingtheoutputvoltage,thedutycycleofthebuck isincreasedtowardmaximumon-timeand100%duty cycle.Theoutputvoltagewillthenbedeterminedbythe input voltage minus the voltage drop across the main switchandtheinductor. VLDO/Linear Regulator Loop IntheLTC3541-1,theVLDOandlinearregulatorloops consist of an amplifier and N-channel MOSFET output stages that, when connected with the proper external components,willservotheoutputtomaintainaregula- toroutputvoltage,LVOUT.Theinternalreferencevoltage providedtotheamplifieris0.4Vallowingforawiderange ofoutputvoltages.LoopconfigurationsenablingtheVLDO orthelinearregulatorarestablewithanoutputcapacitance aslowas2.2 µFandashighas100µF.BoththeVLDO andthelinearregulatorsarecapableofoperatingwithan inputvoltage,VIN,aslowas2.7V,butaresubjecttothe constraintthatVINmustbegreaterthanLVOUT+1.4V. TheVLDOisdesignedtoprovideupto300mAofoutput currentataverylowLVINtoLVOUTvoltage.Thisallows aclean,secondary,analogsupplyvoltagetobeprovided withaminimumdropinefficiency.TheVLDOisprovided withthermalprotectionthatisdesignedtodisablethe VLDOfunctionwhentheoutput,passtransistor’sjunction temperaturereachesapproximately160°C.Inadditionto thermalprotection,short-circuitdetectionisprovidedto disabletheVLDOfunctionwhenashort-circuitcondition issensed.Thiscircuitisdesignedsuchthatanoutput currentofapproximately1Acanbeprovidedbeforethis circuitwilltrigger.AsdetailedintheElectricalCharacter- istics,theVLDOregulatorwillbeoutofregulationwhen thiseventoccurs.Boththethermalandshort-circuitfaults when detected are treated as catastrophic fault condi- |
Similar Part No. - LTC3541EDD-1-PBF |
|
Similar Description - LTC3541EDD-1-PBF |
|
|
|
Link URL |
| Privacy Policy |
| ALLDATASHEET.COM |
| Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Datasheet Upload | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
| Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
|
Family Site : ic2ic.com |
icmetro.com |
English ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
