基于SG3525两相BUCK电路的设计.pdf

摘要

目前，越来越多的设备已不仅仅可由单一电源供电，而要多个电源配合供电来保障

大功率设备的正常工作。本文介绍以SG3525为核心，主体电路采用两路BUCK电路成相

互配合的开关电源电路，介绍了SG3525芯片的工作原理及通过11脚，14脚两脚推挽

输出，两脚相位差180度，通过控制2脚电压，来控制输出电压的占空比，从而影响负

载的的电压。当11脚和14脚的输出电流达到5至10毫安就可以驱动光耦A3120，直接

驱动mos管的栅极。从而驱动主电路。最后比较采样电压来决定改变占空比进行电压调

整。当两路电源有一个支路出现故障时，另一路可以继续供电，保证了系统的正常工作，

提高了供电的可靠性。

关键词：SG3525;PWM,开关电源

Abstract

Atpresent,thetransitionfromunilateralpowersupplytomultilateralpowersuppliesisa

bigprogressforpowerconsumptionequipment.Itmakesureofnormaloperationunder

high-powercondition.Thisarticledescribesaswitchingpowersupplycircuitwhichismadeof

theSG3525asthecoreandtwoBUCKcircuitsasthemaincircuit.Inaddition,itintroduces

howtheSG3525chipworksandhowtocontrolthepush-pulloutputthroughthe11pinand

the14pin.Whatthedifferencebetweentwopinsis180degrees,tocontrolthebilateralvoltage

andthedutycycleofoutputpowerisamethodofcontrollingtheeffectonloadvoltage.When

theoutputcurrentofthe11pinand14pinreaches5~10mA,theA3120OCwillbedrove,and

afterthatthemostubegatewillbedrove.Sothenitwilldrivethemaincircuitto

work.Afterward,itwilladjustthevoltagebymeansofcomparingthesamplingvoltageand

correctingthedutycycle.Ifanerroroccurredinonebranchofbilateralpowersupplies,the

otherwouldcontinuetowork.Thatwillensurethesystemtoworknormallyandimprovethe

reliabilityofpowersupply.

Keywords:SG3525;PWM,switchingpowersupply

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目录

中英文摘要I

1引言1

1.1选题背景及实际意义1

1.2开关电源技术发展概况-1-

1.3本文的主要内容1

2硬件介绍3

2.1SG3525引脚功能及特点简介3

2.2PWM控制基本原理4

3系统设计6

3.1实现功能6

3.2总系统框图6

3.3D