Performing power saving control which can be inherited and standardized
easily, and which keeps power devices from having to become larger is
made possible. A current In flowing through an electrical path is
detected as a voltage Vs by a current detection section, and is outputted
as a voltage Vout by an amplifying section. When a level corresponding to
the voltage Vout exceeds a limit level, a power limit detection section
outputs a power limit detection signal. When a controller receives the
power limit detection signal via a detection signal holding section, the
controller outputs a throttle control command signal. When a chip set
receives the throttle control command signal, the chip set initiates
throttle control that lowers the clock frequency of a CPU. The present
invention may be applied to laptop personal computers.