Patent attributes
An electronic device and its power supply method for charging a battery of the device, which normally operates as a master, through a power supply line, without impairing a function as a master. For example, in an environment where a battery-driven first electronic device and an AC power-driven second electronic device are interconnected via a communication path including a power supply line, it is detected whether or not the capacity of the battery in the first electronic device is sufficient, and in accordance with the result of detection, power supply from the second electronic device is requested. In accordance with the request, electric power from the AC power source of the second electronic device is supplied to the first electronic device via the power supply line, to charge the battery of the first electronic device with the power supply, and it is monitored whether or not the charging has been completed. In accordance with the result of monitoring, the power supply from the second electronic device is stopped, and the first and second electronic devices are returned to a communication stand-by status.
