Patent ID: 7719236

Claim:
A portable electrical device comprising: a DC to DC converter coupled to a common node; a load coupled to said common node; and a controller configured to control said DC to DC converter, said DC to DC converter configured to provide a charging current to a rechargeable battery from an adapter when said controller operates said DC to DC converter in a first adapter supply mode, said DC to DC converter further configured to provide a battery supply current from said battery to said load via said common node when said controller operates said DC to DC converter in a second adapter supply mode; wherein said battery supply current and an adapter supply current provided by said adapter are simultaneously provided in said second adapter supply mode, said adapter supply current and said battery supply current adding together at said common node to provide a load supply current to said load in said second adapter supply mode; wherein said adapter supply current and said battery supply current are simultaneously provided in said second adapter supply mode in response to a single pulse width modulated signal and its complement provided by said controller to said DC to DC converter; and wherein the output of said rechargeable battery is controlled by the DC to DC converter in said second adapter supply mode.