Patent ID: 6820018
Filing Date: 2004-11-16
Classification: G06F

Abstract:
A power control circuit for controlling on/off of power of an electronic device including a power section and a predetermined circuit block, the power control circuit comprising:a power on/off switch having a first switch and a second switch, the first and second switches adapted to be turned on or off simultaneously; a capacitive element connected to the power section via the first switch, said capacitive element adapted to be charged by the power section via the first switch when said power on/off switch is turned off and to be discharged when said power on/off switch is turned on; a first switching element connected to the power section via the second switch, said first switching element adapted to be turned off when said power on/off switch is turned off, and to be in a power-on state while an electric charge that has been charged in said capacitive element is being discharged when said power on/off switch is turned on; a microcomputer for controlling power on/off of said first switching element; and a second switching element provided between the power section and each of said microcomputer and the predetermined circuit block, said second switching element adapted to be turned off to stop power supply to said microcomputer and the predetermined circuit block when said first switching element is turned off, and to be turned on to supply power to said microcomputer and the predetermined circuit block when said first switching element is turned on; wherein said microcomputer is programmed to control the power control circuit such that, when supplying power to said microcomputer, said microcomputer holds the power-on state of said first switching element before said first switching element is turned off because of the discharge of the electric charge charged in said capacitive element, and then, when said microcomputer detects that the predetermined circuit block has not operated for a given period of time, said microcomputer turns off said first switching element.