Design ofaTwo-Stage AC/DC Converter withStandbyPowerLosses Lessthan1 W

The objective ofthispaperistodesign and implement anAC/DCconverter whichmeetsthegreen powerspecification understandby condition. Thedesign of PFC-OFF control and auxiliary circuit whichwill significantly reduce thestandby powertomeettheenergy codeunderstandby condition will bepresented. Moreover, itwill beshownthatthese circuits don't needanycurrent sensor andhysteresis circuit todetect theloadcondition, whichcanreduce thecostandavoid false activation caused bycurrent noise. Thespecifications ofconverter areas follows: universal input voltage: AC 90-265 V,50-60Hz; outputvoltage: 19V/DC;outputpower:250W;standby power:inputpower< 1 W @ 265V/AC input. Experimental results havedemonstrated thattheinput powerfactor isgreater than98% inthewholevoltage rangeandfullloadcondition. Thepowerconsumption understandby condition isless than1W confirming the design andimplementation. IndexTerms:Greenpower,standby power,AC/DC converter.