NCP1271 19V，3.0A通用AC－DC適配器設(shè)計(jì)方案,NCP1271 DESIGN

關(guān)鍵字：NCP1271,開關(guān)電源電路圖

OnSemi公司的NCP1271是一款最新的固定頻率電流模式PWM開關(guān)控制器，具有為低級(jí)聲頻噪聲提供可調(diào)節(jié)的Soft-Skip待機(jī)操作模式，為節(jié)省待機(jī)功耗內(nèi)部集成高壓啟動(dòng)，過載故障檢測(cè)定時(shí)器，內(nèi)部鎖保護(hù)功能特性。本文首先介紹NCP1271、基本特性、內(nèi)部框圖及應(yīng)用領(lǐng)域，并給出相應(yīng)設(shè)計(jì)方案的設(shè)計(jì)原理圖、元器件列表及PCB元件布局圖。
TheNCP1271representsanew,pintopincompatible,generationofthesuccessful7?pincurrentmodeNCP12XXproductseries.

ThecontrollerallowsforexcellentstandbypowerconsumptionbyuseofitsadjustableSoft?Skipmodeandintegratedhighvoltagestartup
FET.ThisproprietarySoft?Skipalsodramaticallyreducestheriskofacousticnoise.Thisallowstheuseofinexpensivetransformersand

capacitorsintheclampingnetwork.Internalfrequencyjittering,rampcompensation,timer?basedfaultdetectionandalatchinputmake

thiscontrolleranexcellentcandidateforconverterswhereruggednessandcomponentcostarethekeyconstraints.

NCP1271主要特性：
?Fixed?FrequencyCurrent?ModeOperationwithRampCompensationandSkipCycleinStandbyCondition
?Timer?BasedFaultProtectionforImprovedOverloadDetection
?“Soft?SkipMode”TechniqueforOptimalNoiseControlinStandby
?InternalHigh?VoltageStartupCurrentSourceforLosslessStartup
?_5%CurrentLimitAccuracyovertheFullTemperatureRange
?AdjustableSkipLevel
?InternalLatchforEasyImplementationofOvervoltageandOvertemperatureProtection
?FrequencyJitteringforSoftenedEMISignature
?+500mA/?800mAPeakCurrentDriveCapability
?Sub?100mWStandbyPowercanbeAchieved
?Pin?to?PinCompatiblewiththeExistingNCP120XSeries
?ThisisaPb?FreeDevice

NCP1271應(yīng)用領(lǐng)域：
?AC?DCAdaptersforNotebooks,LCDMonitors
?OfflineBatteryChargers
?ConsumerElectronicAppliancesSTB,DVD,DVDR

圖1.NCP1271內(nèi)部方框圖

NCP1271ADAPGEVB方案介紹：
Thisevaluationboarduser’smanualpresentsanexamplecircuitusingtheNCP1271(65kHzversion)inaflybacktopology.

Thedesignstepsandsubsequentmeasurementsarealsoincluded.AnExcelbaseddesignworksheetisavailableatwww.onsemi.com.
Themeasurementsshowthatthe19V,3.0Acircuitdeliversabove85%acrossauniversalinput(85to265Vac).Thenoloadstandby

consumptionis83mWat230Vacandthelightloadoperationisgreaterthan75%efficient.

NCP1271ADAPGEVB方案原理圖：

圖2.NCP1271ADAPGEVB方案原理圖

NCP1271ADAPGEVB方案材料清單：


PCB元件布局圖：



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