JPH03296119A - Reducing device for power consumption of personal computer - Google Patents

Abstract

PURPOSE:To reduce the power consumption of a personal computer without disturbing the CPU software under execution by switching a CPU and an input/ output device to the low power consumption state in accordance with the access state of the CPU to the input/output device. CONSTITUTION:A keyboard buffer access detecting circuit 106 detects whether a CPU 103 of a personal computer has been executed an access to the input/ output device provided to the personal computer or not. An access frequency counter circuit 107 and a T1 measuring circuit 109 measure the access frequency or the access cycle. Then a CPU stopping circuit 108 and a CPU driving circuit 111 switch at least the CPU 103 and the input/output device received an access to the low power consumption state from the active state and to reduce the power consumption of the personal computer. For instance, the circuit 108 receives the signals from the circuit 107 and switches the clock of the CPU 103 to a low frequency of the low power consumption state from a frequency of the active state. Thus the power consumption of the personal computer can be reduced without stopping such application software as the calculation software that should not be stopped even after a fixed time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a power consumption reduction device for a personal computer.

[Conventional technology]

Laptop-knob or notebook-type personal computers are becoming widely popular due to their portability. By the way, one of the problems common to such small personal computers is power consumption. That is, these small personal computers use batteries as a portable power source, but the current situation is that they do not operate for more than 2 to 5 hours during normal operation. Therefore, the system is equipped with an automatic CPU stop system that automatically stops the central processing unit (hereinafter referred to as CPU) if no data is input from the input device within a certain period of time, and automatically drives the CPU when data is input. A personal computer is being considered. A block diagram of this automatic CPU stop system is shown in FIG.

Here, the T1 measurement circuit 304 uses the CPU interrupt signal lN.
This circuit uses a counter to measure T1 for a certain period of time from the time when TR goes from high level to low level.

The CPU stop circuit 605 is a circuit that stops the CPU in response to a signal from the TI measurement circuit 304. Further, the CPU drive circuit 606 is a circuit that resets the counter and drives the CPU 301 after the CPU is stopped or at the same time that lNTR becomes high level during counting. That is, when there is no input from the input device for a certain period of time, the CPU clock is stopped and the CPU is placed in a low power consumption state.

[Problem to be solved by the invention]

Conventional automatic CPU shutdown systems have a problem in that application software, such as calculation software, that does not want to be stopped even after a certain period of time has passed, ends up being stopped. Also,
There is a problem in that the display is displayed even when the display section is not being rewritten, and conversely, the display is erased when the display section is being rewritten.

An object of the present invention is to provide a power consumption reduction device for a personal computer that solves these problems.

[Means to solve the problem]

In order to achieve the above object, the personal computer power consumption reduction device of the present invention provides a personal computer power consumption reduction device.
a detecting means for detecting whether or not the PU has accessed an input/output device provided in the personal computer, that is, whether or not the PU has made a data input/output request by specifying the address of the input/output device; A measurement means for measuring the frequency or period, and a CP according to the measurement results of this measurement means.
The present invention is characterized in that it includes a switching means that brings the personal computer into a low power consumption state by switching at least one of the accessed input/output device from an operating state to a low power consumption state.

[Effect]

If software running on a personal computer is waiting for keyboard input, such as word processing software, the CPU
may be stopped until an input is received, but if calculation program software or the like is being executed, the calculation process will stop midway, causing problems. Therefore, in the present invention, it is determined whether or not to stop the CPU depending on the frequency of detecting the address bus signal of the input/output buffer accessed by the CPU. Explain that the CPU can be stopped without any problems.

If your word processing software is waiting for keyboard input,
That software is a keypad pad in memory.

In contrast to frequently accessing the keyboard buffer in memory, when running calculation program software, the keyboard buffer in memory is not accessed at all, or even if it is accessed, it is accessed at relatively small intervals. Therefore, if you stop the CPU when the number of accesses within a predetermined time reaches a certain number, you can also stop application software that you do not want to stop even if it exceeds a certain time, such as calculation software that is running. You won't have to put it away anymore.

t f,-, power consumption of a display system installed in a personal computer can also be reduced by detecting the signal of the address being accessed by the CPU. In other words, it is detected whether the CPU is accessing the VRAM into which display data of the display system is written by detecting the signal on the address bus, and if the VRAM is not accessed even after a certain period of time has passed after the CPU has accessed it, Stops the display controller, turns off the display, and enters a low power consumption state.

[Embodiment 1] FIG. 1 shows the configuration of a device that reduces the power consumption of a personal computer by switching the operating state of a CPU in response to input conditions from a keyboard.

In FIG. 1, 103 is a CPU, 104 is a main memory including a keyboard buffer, and 105 is an address bus.

The T1 measurement circuit 109 receives an interrupt signal l from the keyboard.
This is a circuit that measures time from the time when NTR moves from high level to low level, and outputs a time-up signal when the low level continues for T1.
This circuit sends a pulse to the access count circuit 107 every time the keyboard buffer included in 4 is accessed. The access count circuit 107 counts the number of accesses during the period T1, and when the set count number N is reached, that is, when the CPU is waiting for input, the CPU stop circuit 1
This is a circuit that sends a signal to 08. The CPU stop circuit 108 receives the signal from the access count circuit 107 and stops the CPU
Switch the PU clock from the frequency in the operating state to the lower frequency in the low power consumption state. In addition, the CPU drive circuit 111
When the signal 1NTR changes from a low level to a high level, the CPU which is in a stopped state is driven again by a low frequency clock.

In this embodiment, the detection means described above corresponds to the keyboard buffer access detection circuit 106, the measurement means corresponds to the T1 measurement circuit 109 and the access count circuit 107, and the switching means corresponds to the keyboard buffer access detection circuit 106 based on the present invention. CPU stop circuit 10 that switches from operating state to low power consumption state
8 and a CPU drive circuit 111 that returns to the operating state again.

[Embodiment 2] FIG. 2 shows the configuration of a device that switches to a low power consumption state depending on the access status when a CPU accesses a display device.

In FIG. 2, 201 is a CPU, 204 is a display section of a display device, 206 is a display controller 205 that is a VRAM that stores display data, and 202 is an address bus.

The VRAM buffer access detection circuit 206 is a CPIJ
201 is a circuit that sends a pulse to the T2 measurement circuit 207 every time the VRAM 205 is accessed.

The T2 measurement circuit 207 outputs a signal to the display controller stop circuit 208 if no signal is received from the VRAM buffer access detection circuit 206 for T2 seconds. The display controller stop circuit 208 is a circuit that stops the display controller 206 when it receives a signal from the T2 measurement circuit 207. The display controller drive circuit 209 is a VRA
It receives a signal from the M buffer access detection circuit 206, or drives the display controller 206 when the interrupt signal lNTR from the input device becomes high level.

Incidentally, in this embodiment, the above-mentioned detection means is a VRA.
This corresponds to the M buffer access detection circuit 206, the measuring means is the T2 measuring circuit 207, and the switching means is the display controller stop circuit 208 for switching from the operating state to the low power consumption state and the display for returning to the operating state again, based on the present invention. This corresponds to a circuit consisting of a controller drive circuit 609.

〔Effect of the invention〕

The power consumption reduction device for a personal computer according to the present invention switches the CPU and the input/output device to a low power consumption state depending on the access status of the CPU to the input/output device, so that software being executed by the CPU is not affected. It is possible to efficiently reduce power consumption.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of the first embodiment of the present invention, and FIG. 2 is a diagram of the second embodiment.
Fig. 3 is a block diagram of a conventional device. 106.201...CPU. 105.202...address bus, 104...
... Main memory, 106 ... Keyboard buffer access detection circuit, 107 ... Access count circuit, 108
... CPU stop circuit, 109 ... T1 measurement circuit, 111 ... CPU drive circuit, 203 ... Display controller 204 ...
...Display section, 205...VRAM. 206...VRAM buffer access detection circuit, 207...T2 measurement circuit, 208...Display controller stop circuit, 2
09...Display controller drive circuit. =147

Claims (1)

[Claims] a detection means for detecting an access to an input/output device by a central processing unit of a personal computer; a measuring means for measuring the frequency or cycle of the access; 1. A device for reducing power consumption of a personal computer, comprising: switching means for switching at least one of an input/output device from an operating state to a low power consumption state.