ELECTRONIC DEVICE AND POWER SOURCE CONTROL METHOD

摘要

An electronic device and a power source control method capable of efficiently switching the input power source according to the load of a device. Upon detection of a USB connection, a power control unit (50) monitors its power consumption from the operation condition of a CPU (44) and controls a switch (42) according to the current supplied from a USB cable (2). When the current is 500 mA or below, the switch 42 is set to a terminal "a". When the current becomes 100 mA or below before configuration, the switch 42 is set to the terminal "a" and a regulator (43) is controlled so that the current does not exceed 100 mA. Upon USB suspension, the switch 42 is set to a terminal "b" and output from the regulator (53) to a backup battery (54) is stopped. The present invention can be applied to a USB-based digital still camera.