Patent ID: 8046612

Claim:
A power control system, comprising: a power adapter, comprising: a first switch, directly coupled to a power, for controlling the power according to a plurality of logic states; and a power circuit, coupled to the first switch, for converting a voltage of the power, so as to be provide the converted voltage to a portable electronic device; and a monitoring device, disposed in the portable electronic device, comprising: a latch, coupled to the first switch, for latching the first switch according to the logic states; a controller, coupled to the latch, for detecting a connection status and an electric quantity of a battery, generating the plurality of logic states, and transmitting the logic states to the latch, so as to turn on/off the latch for latching the first switch, and thus controlling an input of the power, wherein if the electric quantity of the battery has not yet reached a reference value, the controller turns on the latch for latching the first switch to provide the power to the power circuit, and if the battery is not detected or the electric quantity of the battery has already reached the reference value, the controller turns off the latch for latching the first switch to stop providing the power to the power circuit; and a second switch, for controlling power on/off of the portable electronic device, wherein when the second switch is turned on to power on the portable electronic device, the latch is enabled to turn on the first switch, such that the power circuit provides the power to the controller.