Circuit and method for electricity saving of centeral processor

Abstract

The invention is an electricity-saving circuit for a CPU, comprising a switch transistor whose first source / drain is grounded and whose second source / drain is coupled with an external power supply and whose gate is coupled with the CPU. As the CPU normally operates, it will turn on the switch transistor and as the CPU enters in an electricity-saving mode, it will turn off the switch transistor. Besides, it also comprises a diode whose anode is coupled with the second source / drain and whose cathode is used to couple with highest-bit code element of voltage recognizing code of the CPU so as to output the highest bit code element.

Description

technical field [0001] The present invention relates to a power-saving circuit and method for a central processing unit, and in particular to a power-saving circuit and method for adjusting the operating voltage of a central processing unit by changing a voltage identification code. Background technique [0002] In a computer system, the operating voltage required by the central processing unit is determined by a voltage identification code (Voltage Identification Code, VID for short) generated according to its working mode. [0003] FIG. 1 is a block diagram illustrating a conventional operating voltage supply for a central processing unit. Please refer to FIG. 1 , in a general computer system, the central processing unit 101 generates a voltage identification code VID according to a required operating voltage Vcore. As shown in FIG. 1 , the central processing unit 101 outputs a voltage identification code VID to a pulse width modulation (PWM) device 103 . The pulse width...

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Problems solved by technology

But on some CPUs (such as Celeron Pentium  M series) will not automatically reduce the required operating voltage value when entering power saving mode, so the power saving efficiency of computer systems using this type of CPU is very low

And if a notebook computer uses this kind of central processing unit with low power-saving efficiency, it will also shorten the life of the battery.

[0005] As mentioned above, this type of CPU with poor power saving efficiency is not mainstream in the market.

However, in order to reduce the cost of the computer system, it is sometimes considered to use these central processing units with poor power saving efficiency.

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