Patent ID: 6973584
Filing Date: 2005-12-06
Classification: G06F,Y02D

Abstract:
1. A method for reducing current consumption of a mobile communication terminal including a timer and a phase locked loop (PLL) capable of varying a main clock frequency of a CPU (Central Processing Unit), the method comprising the steps of: (a) if all effective tasks performed by a program of the mobile communication terminal are blocked, performing a simple infinite loop, performing a count idle task for counting a global variable value for a predetermined time, and measuring the global variable value of the count idle task, counted for the predetermined time according to a timer interrupt generated by the timer every unit time, as a reference value of an idle task; (b) if the mobile communication terminal performs an effective task according to a random program operation, performing the count idle task for a period where the idle task is performed, according to a timer interrupt generated by the timer every unit time, and measuring the counted global variable value as an idle value of the effective task; (c) calculating a random idle rate representing the CPU occupation rate of the idle task by dividing the idle value of the effective task by the reference value, while the random program is performed, and setting a target idle value according to a value calculated by multiplying a specific idle rate, which is previously calculated corresponding to a main clock frequency capable of being set in the CPU, by the reference value; and (d) if the program performs an effective task, measuring an idle value of the effective task by performing the count idle task, comparing the measured idle value with the idle target value, decreasing the main clock frequency through the PLL if the measured idle value of the effective task is larger than the idle target value, and increasing the main clock frequency if the measured idle value of the effective task is smaller than the idle target value, thereby adjusting the main clock frequency.