Patent attributes
The present invention relates to an electronic apparatus and a power supply controlling method with which input power source is switched efficiently in accordance with a load of a device. A power controller 50, upon detecting a USB connection, monitors power consumption of a CPU 44 based on the operation status of the CPU 44, and controls a switch 42 in accordance with a current supplied from a USB cable 2. When the current is less than or equal to 500 mA, the switch 42 is switched to a terminal a. Before configuration, when the current is less than or equal to 100 mA, the switch 42 is switched to the terminal a, and then a regulator 43 is controlled so that the current will not exceed 100 mA. In USB suspend, the switch 42 is switched to a terminal b, and a regulator 53 stops output to a backup battery 54. The present invention can be applied to a digital still camera supporting USB.