Patent ID: 8169196

Claim:
A method performed by a charging device, the method comprising: monitoring a voltage signal from an external device against a predetermined voltage threshold; monitoring an electrical current signal from the external device against a predetermined current threshold; detecting whether the external device is both present and charging based on a combination of the monitored voltage signal, with respect to the predetermined voltage threshold, and the monitored electric current signal, with respect to the predetermined current signal; setting a switch on a primary side of the charging device to an off state when the presence and charging of the external device are not detected, where, when the switch on a primary side of the charging device is set to an off state, the charging device consumes no power; detecting when both the charging device is reconnected to an AC voltage and when the external device was previously connected to the charging device; and in response to the detecting when both the charging device is reconnected to an AC voltage and when the external device was previously connected to the charging device, controlling and powering switching logic to an on state.