80C51便携式产品中的低功耗设计
> 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
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
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