JP2007115070A - Information processor and cooling fan control method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an information processor and a fan control method therefor, in which a CPU is suitably cooled using a plurality of fans in an information processor such as a desktop computer. <P>SOLUTION: Of the plurality of fans provided for cooling the CPU, the rotating speed of a fan distant from an exhaust port provided on a casing is set relatively higher than those of other fans, and an atmospheric pressure distribution is generated within the casing to improve the exhaust efficiency. Further, the rotating speeds of the plurality of fans are controlled to be varied to prevent whirring of the fans. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fan control method suitable for cooling a CPU using a plurality of fans in an information processing apparatus such as a desktop personal computer.

  In recent years, methods for digitizing video information have been standardized, and viewing and recording / playback functions of video from TV broadcasts and DVD media are also required as important functions in PCs.

  Also, since it is used in the same environment as an existing AV (audiovisual) device for viewing video content, the appearance design is also required to be compatible with the existing AV device. Thinning is required.

  On the other hand, in order to handle video information, the CPU is required to have high performance, so the amount of heat generated by the CPU tends to increase. The problem of heat generation of the CPU in a small and thin casing and the noise caused by the fan that cools the CPU This problem is particularly problematic when viewing video content.

  Conventionally, a method of using a plurality of fans is often used as a cooling method of a computer system. A method of measuring the temperature of the CPU and controlling the rotational speed of the fan according to the CPU temperature is also well known.

  For example, Patent Document 1 describes a method of controlling a computer system having a plurality of fans so as to synchronize the rotation speeds of the plurality of fans.

JP 2001-15972 A

  Although it is possible to apply the above-described conventional technology to a thin desktop PC, there is a problem that the control circuit of the cooling fan becomes complicated simply by applying it, leading to an increase in the cost of the PC.

  In addition, according to the prior art, the rotation speeds of a plurality of fans are synchronized, but if a slight shift in the rotation speed occurs, a roaring sound may be generated. In addition, since a plurality of cooling fans are operated, the driving sound of the cooling fans is increased. For this reason, there is a problem that the roaring sound and the driving sound of the cooling fan interfere with the viewing of the video content.

  An object of the present invention is to provide an information processing apparatus and a fan control method suitable for solving the above problems when a CPU is cooled using a plurality of fans in a thin desktop PC.

  In order to solve the above-described problems, an information processing apparatus according to the present invention includes a heat dissipating fin that cools a heat generating part, a plurality of heat dissipating fans that are installed in parallel to the heat dissipating fin and send cooling air, and a temperature of the heat generating part. A temperature sensor to detect, and a fan control circuit that controls each operating condition of the heat radiating fan in response to the temperature of the heat generating part detected by the temperature sensor, the fan control circuit of the cooling fan The number of revolutions was controlled so as to be different.

  Further, the plurality of heat dissipating fans are disposed at different positions from the cooling air exhaust port of the information processing apparatus, and the fan control circuit discharges the heat dissipating fan according to the distance from the air exhaust port. The pressure was controlled to be high.

  According to the present invention, since the information processing apparatus can be quieted by reducing the cooling fan driving sound by preventing the generation of beat noise and improving the exhaust efficiency, the existing AV for viewing video contents on the PC can be used. It can be handled in the same way as a device, and the availability of the PC can be improved.

Hereinafter, an embodiment of a desktop personal computer (hereinafter referred to as a PC) to which the present invention is applied will be described with reference to the drawings.
FIG. 1 is a diagram showing a system configuration of a PC. The PC system of the present embodiment includes a PC 1 having a CPU, a memory, a drive storing a program such as an OS, a monitor 2 for displaying the processing contents of the program, a keyboard 3 and a mouse 4 for inputting user operation information. Consists of a remote control 5

  The monitor 2 has a monitor video input such as a PC analog video signal, DVI (Digital Visual Interface), HDVI (High-Definition Multimedia Interface), etc., and displays a video signal output from the PC 1 on a display unit such as an LCD. It incorporates a read / write drive (not shown) and a speaker for optical disks such as -R and semiconductor memory cards. These drives are connected to the PC 1 by a cable and are configured to be readable and writable from the PC.

  The keyboard 3, mouse 4, and remote controller 5 communicate operation information through an infrared interface or a wireless interface built in the monitor 2. These pieces of operation information are notified to the PC 1 via a cable connecting the monitor 2 and the PC 1.

  FIG. 2 is a perspective view showing the internal configuration of the PC 1 to which the present invention is applied. FIG. 2 is a perspective view obliquely viewed from above when the PC 1 is placed flat. The PC 1 is provided with a mother board 6 on which a CPU and a chip set are mounted on the bottom surface. The motherboard 6 is also equipped with an interface connector for connecting an external device such as the monitor 2 with a cable. The connectors are arranged in a concentrated manner at one end of the mother board in consideration of cable connectivity, and are further stored in the PC 1 so that the end of the mother board 6 on which the connectors are arranged is located on the back of the apparatus.

  A CPU (not shown) is mounted on the mother board 6, and heat radiating fins 7 for cooling the processor are stacked on the processor.

  A plurality of radiating fans 81 to 83 having a size corresponding to the width of the casing are installed according to the width of the radiating fins 7.

  The size of the radiating fins 7 and the number of the radiating fans 81 to 83 are determined so that the CPU does not use the maximum capacity of the radiating fans 81 to 83 in the normal operation state, particularly when reproducing video contents such as TV viewing and DVD playback that are expected to be quiet. It is preferable to determine so that it can be sufficiently cooled.

  An intake port is provided on the front surface (intake side) of the radiating fans 81-83. By this intake port, the direction of the flow of the outside air sucked from the intake hole 9 provided on the side surface of the apparatus is changed from the front to the back of the apparatus.

  The expansion board 10 is installed in parallel with the mother board 6 so as not to prevent the cooling air that has flowed through the radiating fins 7 from flowing to the back surface of the apparatus. Similarly, the memory 11 is also arranged from the front side to the back side of the apparatus in accordance with the flow direction of the cooling air.

  A drive 12 such as an HDD for storing programs and data is installed on the front side of the PC 1, and a power supply unit 13 of the PC 1 is arranged behind the drive 12.

  With reference to FIG. 3, the arrangement of the cooling air suction port and the exhaust port of this embodiment will be described. FIG. 3 is an overview perspective view when the PC 1 is installed vertically.

  The cooling air suction port 9 of this embodiment is provided on both side surfaces on the front side of the PC 1 (corresponding to a bottom surface portion and a top surface portion at the time of installation) with a predetermined width from the upper part to the lower part of the apparatus. When the PC 1 is installed stationary or when the PC 1 is installed in a vertical arrangement with another device, the amount of outside air flowing from the inlet provided on one side is reduced. It is good to decide.

  The following exhaust port is provided on the back side of the PC 1. First, an exhaust port 16 is provided on the side surface opposite to the mother board 6 of the PC 1 (corresponding to the top surface portion when stationary). Second, an exhaust port 17 is provided at the top of the PC 1.

Next, the flow of the cooling air inside the PC 1 will be described in detail with reference to FIG.
FIG. 4 is a diagram for explaining the flow of cooling air when the vertically placed PC 1 is viewed from the side (the stationary PC 1 is viewed from above). A CPU 8 is installed under the cooling fin 7 so as to be in contact with the cooling fin 7. In addition, the flow of cooling air for cooling the CPU 8 in the normal operation state is indicated by the hatched arrow direction, and the strength of the cooling air is indicated by the size of the arrow.

  First, the flow of cooling air on the mother board 6 side will be described. The outside air is sucked into the inside from the suction port 9 provided on the side surface of the apparatus by the cooling fans 81 to 83, and the direction of the flow changes at the intake port formed by the cooling fans 81 to 83 and the housing. The cooling air discharged by the cooling fans 81 to 83 flows through the cooling fins 7 provided in the CPU 8 of the mother board 6. Since the cooling fins 7 are provided in the direction of the flow of the cooling air, the cooling air flows smoothly, and the CPU 8 is cooled by receiving the heat generated by the CPU 8 from the cooling fins. The cooling air that has passed through the cooling fins 81 to 83 flows while cooling another device (for example, a chip set) of the motherboard 6 and the expansion board 10 such as a display board installed in parallel to the motherboard 6. Then, the air is exhausted from the exhaust port 16 provided on the side surface of the PC 1 and the exhaust port 17 provided on the upper side of the PC 1 by changing the flow direction to the outside of the apparatus.

  Next, the effect on the flow of the cooling air by adjusting the rotational speed of the cooling fans 81 to 83 of the present invention will be described with reference to FIG. In the present invention, the rotational speed of the cooling fan 81 close to the inside of the housing is made relatively higher than the rotational speed of the cooling fan 83 close to the outside. By so doing, it is possible to provide a gradient in the atmospheric pressure from the inside to the outside of the housing, and the cooling air that has received the heat generated by the CPU 8 via the cooling fins 7 can be efficiently exhausted. Since the cooling air exhausted from the exhaust ports 16 and 17 to the outside of the casing has a relatively high temperature relative to the outside air temperature and rises by natural convection, the gradient of the atmospheric pressure not only inside the casing but also around the casing is increased. It is possible to provide a smooth flow of cooling air.

  Another advantage of the present invention is that the CPU can be sufficiently cooled without using the maximum capacity of the heat dissipation fans 81 to 83 during the reproduction of video contents such as TV viewing and DVD reproduction, which are expected to be quiet in the normal operation state. By determining the size of the radiating fins 7 and the number of the radiating fans 81 to 83, the noise generated by the radiating fans 81 to 83 can be reduced. Moreover, since the frequency of noise generated by the fan is determined by the number of fan wings and the number of rotations, no beat is generated by rotating the same fan at a different number of rotations. When the same fan is rotated at the same number of rotations, an irritating beat is generated unless a synchronization mechanism such as that disclosed in Patent Document 1 is provided.

  Next, the fan control method of the present invention will be described with reference to FIGS. FIG. 5 is a block diagram of a fan control circuit. The control LSI 30 corresponds to the cooling fans 81 to 83 and has fan control units 31 to 33 for controlling them. The fan control units 31 to 33 receive temperature information from a temperature sensor (not shown) that measures the temperature of the CPU 8 via the signal line 39, and generate fan control signals 34 to 36 based on preset fan control information. . The fan control information is set via the data bus 40 at the time of system initialization or the like by a program such as BIOS, but the setting method may be performed in the same manner as various registers set at the time of initialization. Is omitted.

  Next, fan control information set at initialization will be described with reference to FIG. FIG. 6 is a graph for explaining fan control information set in a fan control information register (not shown) in the fan control units 31 to 33. The horizontal axis represents the measured temperature (° C.) of the CPU 8, and the vertical axis represents the rotation speed (rpm) of the cooling fans 81 to 83 controlled by the fan control signals 34 to 36 output from the fan control units 31 to 33. Two temperatures are set in the fan control information register: a temperature tmim at which rotation starts (rotation speed is Rmin) and a temperature tmax at which rotation is performed at the maximum rotation speed (Rmax) (tmin <tmax). At a temperature between tmin and tmax, the rotational speed of the cooling fan is controlled to increase linearly.

  In the fan control information register of the fan control unit 31, t1 and t4 are set. Similarly, t2 and t5 are set in the fan control information register of the control unit 32, and t3 and t6 are set in the fan control information register of the control unit 33. In the present embodiment, t1 <t2 <t3 <t4 <t5 <t6 is set.

  When the temperature of the CPU 8 is tn (t3 <tn <t4), the rotation speeds of the cooling fans 81 to 83 output by the fan control units 31 to 33 are R1tn, R2tn, and R3tn, respectively, and are cooling fans close to the inside of the housing 81 is the maximum number of rotations, and is set so that the number of rotations gradually decreases toward the outside of the housing.

  Next, it will be described that it is relatively easy to keep the temperature of the CPU 8 in the normal operation state between t3 and t4. The amount of heat generated by the CPU 8 varies according to the process being executed by the CPU 8. The amount of heat generated is high in scientific and technical calculations where the access to the main memory is relatively small and the calculation resources in the CPU 8 such as the arithmetic logic operation unit and the floating point processing operation unit are frequently used. On the other hand, in the processing of playback of video content that requires silence, the main memory is accessed frequently and the arithmetic logic operation amount is relatively large, but the floating point operation unit is rarely used, so the amount of heat generation is not small. Is not so close to the maximum. Further, when normal paperwork such as text editing or spreadsheet is performed, the CPU 8 is almost waiting for input and generates a small amount of heat.

  For this reason, if the maximum heat generation amount of the CPU 8 can be cooled by using the maximum capacity of the cooling fans 81 to 83, the temperature of the CPU 8 can be maintained in a normal operation state such as reproduction of video contents and office processing that require silence. Is easily kept between t3 and t4.

  According to this embodiment, it is possible to achieve sufficient performance for cooling the CPU even in a small and thin casing by having a plurality of fans while suppressing noise.

  In addition, according to the present invention, since a pressure gradient can be created from the inside to the outside in the housing, the warm air can be exhausted efficiently, thereby reducing the number of fan rotations and noise. Can contribute.

  In addition, since the fan having the highest rotation speed and the resulting loud noise is inside, there is an effect of further reducing the noise leaking outside the housing.

  Furthermore, when the same rotation speed is set without providing a mechanism for synchronizing the rotation speed of the fan, a slight difference in the rotation speed may cause annoying beating at a low frequency. Since the rotation speeds of the plurality of fans are made different, there is also an effect of suppressing beat.

System Configuration Device configuration perspective view Device perspective view The figure which shows the ventilation path of the cooling air inside the device Fan control circuit block diagram Graph explaining information to be set in the fan control unit

Explanation of symbols

1 ... PC, 2 ... monitor, 3 ... keyboard, 4 ... mouse, 5 ... remote control,
6 ... Motherboard, 7 ... Radiation fin, 8 ... CPU, 81-83 ... Radiation fan,
9 ... Inlet, 10 ... Expansion board, 11 ... Memory, 12 ... Drive,
16, 17 ... exhaust port, 30 ... control LSI, 31-33 ... fan control unit,
34 to 36: Fan control signal, 39: Signal line, 40: Data bus

Claims (3)

Radiating fins for cooling the heat generating part;
A plurality of heat dissipating fans installed in parallel to the heat dissipating fins and sending cooling air;
A temperature sensor for detecting the temperature of the heat generating part;
A fan control circuit that controls each operation of the heat dissipation fan in response to the temperature of the heat generating part detected by the temperature sensor,
The information processing apparatus according to claim 1, wherein the fan control circuit controls the cooling fan so as to have different rotation speeds. The information processing apparatus according to claim 1,
The plurality of heat dissipating fans are disposed at different positions from the cooling air exhaust port of the information processing device, respectively.
The information processing apparatus according to claim 1, wherein the fan control circuit controls the discharge pressure of the heat radiating fan to be high according to a distance from the exhaust port. In the fan control method of the information processing apparatus that cools the heat generating part with a plurality of heat dissipation fans,
Each operating condition of the heat dissipation fan is set in advance according to the distance from the exhaust port of the information processing device,
Detecting the temperature of the heat generating part of the information processing device;
A cooling fan control method for an information processing apparatus, wherein an operating condition of the cooling fan is obtained according to the detected temperature to drive the heat dissipation fan.

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