Patent ID: 9678554
Date: 2017-06-13
CPC Classifications: G06F

Claim:
1. A power management circuit, which is coupled to a computer system to additionally manage a power supply of the computer system to ensure that the computer system possesses adequate power to boot up, the power management circuit comprising: a power switch, configured to couple to the power supply of the computer system, wherein when the power switch is turned on, the power switch supplies an output current and an output voltage of the power supply to an external device; a current/voltage detector, coupled between the power switch and the external device, and detecting magnitudes of the output voltage and the output current; and a control unit, coupled to the power switch, and the current/voltage detector, and defining a first threshold voltage to be an amount of voltage to which the power supply provides to the external device while the power supply still has sufficient power to boot up the computer from a power-saving state, wherein when the computer system is in the power-saving state and when the output voltage is smaller than the first voltage threshold and larger than a second voltage threshold, the control unit issues a first notification signal instructing the power supply to enter a working state from the power-saving state, wherein when the computer system is in the power-saving state and the output voltage is smaller than the second voltage threshold, the control unit turns off the power switch to cut off the output current supplied by the power supply to the external device, wherein the control unit issues a second notification signal after the control unit turns off the power switch and the output voltage of the power supply reaches a third voltage threshold due to cutting off the output current to the external device, wherein the third voltage threshold is greater than or equal to the first voltage threshold, wherein the control unit turns on the power switch to resume the supply of the output current and the output voltage after the control unit turns off the power switch and the output voltage of the power supply reaches the third voltage threshhold due to cutting off the output current to the external device.