您现在的位置: 范文先生网 >> 理工论文 >> 电子通信论文 >> 正文

80C51便携式产品中的低功耗设计

时间:2007-1-20栏目:电子通信论文

>  对于钮扣电池供电的设备,关机态的电流消耗也是不可忽略的。10μm的关机电流累积一个月,就会消耗大于6%的电池容量。
  
  关断整机电流的简单方法是用CMOS触发器控制一个晶体管做的电子开关,通常开关三极管的截止电流小于500mA。
  
  图2是我们设计的智能电源控制电路,靠一个耗电极少的单片机PIC12LC508A控制晶体管电子开关和DC-DC变换器,可以实现单键开关机、自动关机、禁止关机、定时开机等功能。
  
  现在,越来越多的电池变换芯片具有SHUTDOWN引脚和电流与负载断开的功能。采用这一特性实现的电路,使用与图2类似的原理,关机电流也可以达到1μA以下。
  
  
  
  keateenagerthanatwelveyearold,yet,Stevewentunnoticed...untilMissWhite.MissWhitewasasmiling,young,beautifulredhead,andStevewasinlove!Forthefirsttimeinhisyounglife,hecouldn’ttakehiseyesoffhisteacher;yet,stillhefailed.Heneverdidhishomework,andhewasalwaysintroublewithMissWhite.Hisheartwouldbreakunderhersharpwords,andwhenhewaspunishedforfailingtoturninhishomework,hefeltjustmiserable!Still,hedidnotstudy.Inthemiddleofthefirstsemesterofschool,theentireseventhgradewastestedforbasicskills.Stevehurriedthroughhistests,andcontinuedtodreamofotherthings,asthedayworeon.Hisheartwasnotinschool,butinthewoods,whereheoftenescapedalone,tryingtoshutoutthesights,soundsandsmellsofhisalcoholichome.Noonecheckedonhimtoseeifhewassafe.Nooneknewhewasgone,becausenoonewassoberenoughtocare.Oddly,Stevenevermissedadayofschool.Oneday,MissWhite’simpatientvoicebrokeintohisdaydreams.“Steve!!”Startled,heturnedtolookather.“Payattention!”StevelockedhisgazeonMissWhitewithadolescentadoration,asshebegantogooverthetestresultsfortheseventhgrade.“Youalldidprettywell,”shetoldtheclass,“exceptforoneboy,anditbreaksmyhearttotellyouthis,but...”Shehesitated,pinningStevetohisseatwit

上一页  [1] [2] [3] [4] [5] [6] [7] 下一页

下页更精彩:1 2 3 4 下一页