Patent ID: 7791854

Claim:
A current limit protection apparatus, comprising: a metal-oxide-semiconductor (MOS) transistor, comprising a first source/drain for receiving a first voltage, a second source/drain of the MOS transistor for outputting a second voltage, and a gate for receiving a gate driving signal to determine a conducting current of the MOS transistor; a current detecting unit, for detecting the conducting current of the MOS transistor, so as to generate a detecting result; and a current limit circuit, having a plurality of current threshold values, for selecting one of the current threshold values according to a first indicating signal and generating the gate driving signal according to a difference between the selected current threshold value and the detecting result, wherein the first indicating signal is output from an advanced configuration and power interface (ACPI) controller disposed in a computer system, the computer system has a plurality of predetermined energy-saving modes, and the first indicating signal is used for indicating whether the computer system is in one of the predetermined energy-saving modes or not; when the first indicating signal indicates the computer system is in one of the predetermined energy-saving modes, the current limit circuit limits the conducting current of the MOS transistor to the selected current threshold value to prevent a power supply of the computer system from overloading such that the computer system can smoothly recover to a normal mode from the one of the predetermined energy-saving modes.