JPH11233984A - Cooling system for electronic device comprising heat-generating part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling system for appropriately controlling the running of a cooling fan according to generated heat amount, etc., of an electronic device comprising a heat-generating part. SOLUTION: In an optimum value table which describes relation among a fan controller 202 which outputs measurement data regarding the number of rotations of a cooling fan 201, an identifier provided at a heat-generating component such as a CPU card 10, and an optimum number of rotations of a fan, each table entry comprises an optimum value table where at least two optimum number of rotations corresponding to at least two threshold temperatures, a temperature measurement device 204 for measuring the temperature around a heat-generating part, the number of rotations deciding means for deciding the current optimum number of rotations according to the identifier and measured temperature of the heat-generating component, and a cooling system controller which corrects the on/off duty factor of a drive power source supplied to a fan, based on the difference between the optimum number of rotations and actual number of rotations of the fan obtained through the fan controller.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling system for an electronic device including a heat-generating component, and more particularly, to a cooling system of a type that dissipates heat generated in the device by a cooling fan. More specifically, the present invention relates to a cooling system that appropriately controls the rotation of a cooling fan according to the amount of heat generated.

[0002]

2. Description of the Related Art With the recent technological innovation, various personal computers (PCs) such as a desktop type, a tower type, and a notebook type have been developed and marketed.

As is well known, these computer systems (hereinafter, also simply referred to as “systems”) have a CPU.
(Central Processing Unit), memory, video controller chip, and other circuit components. In recent years, the operating frequency of the system has been further increased with the improvement in semiconductor manufacturing technology such as reduction in the width of wiring. For example, the CPU chips "MMX Technology Pentium" and "P
Operating frequency such as entium II "is super 200 MH
It is z-class.

[0004] Higher operating frequencies have the benefit of increasing the processing power of the system. For example, the calculation speed will increase with the speeding up of the CPU chip, and it will be effective in large-scale applications and graphics processing.

On the other hand, increasing the speed of the system causes some adverse effects. One of them is the problem of fever. This is because an increase in the operating frequency means an increase in the amount of current passing through the transistor gate (ie, the resistor) per unit time, and as the current increases, the amount of heat generation naturally increases. The main heat sources in the system are a high-speed CPU, an external cache memory (usually composed of SRAM chips), and a bridge chip (commonly called "North Bridge") interconnecting the CPU and the local bus. ). For this reason, many recent personal computers employ a cooling system.

[0006] The cooling system includes a "forced cooling type" in which hot air in the system housing is forcibly replaced by the outside by rotation of a cooling fan, and a member having excellent heat conductivity such as a heat pipe or a heat sink. There is a “natural cooling type” in which heat is released to the outside through these heat transfer members by contacting a source component. The term `` heat pipe '' here refers to a configuration in which a non-condensable gas such as air is evacuated and then a condensable fluid such as water or ammonia is sealed as a working fluid. At a high speed (known). Although the forced cooling system using a cooling fan has a higher cooling effect, it naturally consumes power for its driving. For this reason, it is common to use a cooling fan for a desktop PC driven by an inexhaustible commercial power supply and to use natural cooling using a heat pipe for a notebook PC driven by a battery having a finite capacity.

However, the speed of notebook controller chips and the like has been increased, and it has become almost impossible for notebook PCs to rely only on natural cooling. In the first place, a notebook PC has a high degree of integration of circuit components and the like in a housing, and has a structure in which heat is easily stored inside. In order to satisfy the operation guarantee temperature of these circuit components, notebook PCs with a built-in cooling fan (that is, a forced cooling system) have recently been increasing.

It can be easily conceived that as the cooling fan rotates at a higher speed, its cooling effect increases. However, high-speed rotation of the fan involves a trade-off between an increase in power consumption for driving the fan motor and an increase in noise generated by the rotation of the fan motor.
For this reason, the rotation speed of the cooling fan is appropriately adjusted according to the temperature in the system housing (or the heat-generating components), such as rotating the fan at a low speed at a relatively low temperature stage and switching to a high speed rotation at a high temperature. You need to control.

However, in general, there are individual differences in the motors that rotate the fans, and the number of rotations obtained by applying the same drive voltage to the motors varies. In addition, the rotation characteristics of the motor are easily affected by the environment such as the ambient temperature and changes over time, and the same rotation speed cannot always be obtained with the same drive voltage even with the same motor. The set rotation speed of the cooling fan, that is, the optimum rotation speed is, for example, 4,000 at high speed.
At 0 rpm and at low speed, the value is about 3, ooorpm, while the variation in the fan rotation speed is at most 1,000
It may exceed 0 rpm. Since the variation is larger than the difference between the high speed and the low speed, the setting of the speed has little meaning. That is,
At present, it is not easy to control the rotation of the cooling fan.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide an excellent cooling system for an electronic device including a heat-generating component.

It is a further object of the present invention to provide an excellent cooling system of a type that dissipates heat generated in equipment by rotation of a fan.

It is a further object of the present invention to provide an excellent cooling system for appropriately rotating a fan according to the amount of heat generated.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and a first aspect of the present invention relates to a cooling system for an electronic device including a heat-generating component. ) A cooling fan, (b) a fan controller for rotating the fan by a driving power source, and outputting measurement data on the rotation speed of the fan, and (c) supplying the fan according to the measurement data on the rotation speed of the fan. A cooling system controller that corrects a duty ratio of drive power on / off.

According to a second aspect of the present invention, there is provided a cooling system for an electronic device including a heat-generating component.
A cooling fan; (b) a fan controller for rotating the fan by a driving power source and outputting measurement data on the rotation speed of the fan; and (c) rotation of the fan according to the measurement data on the rotation speed of the fan. A cooling system controller that corrects a duty ratio of drive power supply on / off supplied to the fan so that the number approaches an optimum value.

According to a third aspect of the present invention, there is provided a cooling system for an electronic device including a heat-generating component.
A cooling fan, (b) a fan controller for rotating the fan by a driving power source and outputting measurement data on the number of rotations of the fan, and (c) a temperature measuring device for measuring a temperature around the heat-generating component. (D) determining an optimum rotation speed of the fan based on the measured temperature and supplying the fan to the fan according to a difference between the actual rotation speed of the fan obtained via the fan controller and the optimum rotation speed; A cooling system controller that corrects a duty ratio of drive power on / off.

According to a fourth aspect of the present invention, there is provided a cooling system for an electronic device including a heat-generating component.
A cooling fan, (b) a fan controller for rotating the fan by a driving power source, and outputting measurement data on the number of rotations of the fan, (c) an identifier provided on the heat-generating component, and (d) An optimal value table describing the relationship between each identifier of the heat-generating component and the optimal rotational speed of the fan; and (e) a rotational speed for reading the identifier of the heat-generating component and determining the optimal rotational speed by referring to the optimal value table. Determining means; and (f) a cooling system for correcting a duty ratio of drive power supply on / off supplied to the fan according to a difference between an actual rotation speed of the fan and the optimum rotation speed obtained via the fan controller. A cooling system comprising: a controller;

According to a fifth aspect of the present invention, there is provided a cooling system for an electronic device including a heat-generating component.
A cooling fan, (b) a fan controller for rotating the fan by a driving power source, and outputting measurement data on the number of rotations of the fan, (c) an identifier provided on the heat-generating component, and (d) An optimal value table describing a relationship between each identifier of a heat-generating component and an optimal rotational speed of the fan, wherein each table entry stores two or more optimal rotational values corresponding to two or more threshold temperatures. A value table, (e) a temperature measuring device for measuring the temperature around the heat-generating component, (f) rotation speed determining means for determining a current optimum rotation speed according to the identifier of the heat-generating component and the measured temperature, and (g) Correcting the duty ratio of drive power supply on / off supplied to the fan according to the difference between the actual rotation speed of the fan and the optimum rotation speed obtained via the fan controller A cooling system controller that,
It is a cooling system characterized by comprising:

Thus, according to the cooling system of the present invention, feedback control can be performed so that the number of rotations of the cooling fan becomes an optimum value.

Further, according to the cooling system of the present invention, the optimum rotation speed of the cooling fan can be dynamically switched according to the temperature of the heat-generating component, that is, the amount of heat generated.

The heat-generating component is, for example, a CPU card mounted on a system board of a notebook PC. C
The PU card includes, for example, a heat-generating circuit component such as an external cache memory and a bridge chip in addition to a CPU chip. Generally, the heat generation characteristic of generating heat differs for each heat generation component. For example, the type of CPU chip (Pentium or Penti
um II), its operating frequency, and the type and capacity of the external cache memory, the amount of heat generation differs, and naturally, the optimum rotational speed of the fan also differs. According to the present invention, it is also possible to read the identifier of the heat-generating component and determine the optimum rotational speed in accordance with the identifier.

Still other objects, features and advantages of the present invention are:
It will become apparent from the following more detailed description based on the embodiments of the present invention and the accompanying drawings.

[0022]

Embodiments of the present invention will be described below in detail with reference to the drawings.

A. 1. Configuration of Computer System FIG. 1 schematically shows a hardware configuration of a typical personal computer (PC) 100 suitable for realizing the present invention. One example of a computer system 100 that implements the present invention is IBM Japan, Ltd.
"ThinkPad 7" Notebook PC
xx "series (" ThinkPad "is a trademark of IBM Corporation of the United States.) The system 100 is OADG (PC Open Ar
It conforms to the specifications of "ChitectureDeveloper's Group" and uses Microsoft's "Windows 95" or IBM's "OS / 2" as the operating system (OS).
("OS / 2" is a trademark of IBM Corporation in the United States). The system 100 includes, as major hardware components, C
It includes card modules such as a PU card 10, a planar card 20, a video card 50, a multimedia card 60, and a modem card 70. Hereinafter, each unit will be described.

The CPU card 10 includes a CPU 11 as a main controller and an external cache memory (L2
-Cache 12 and a bridge circuit (host-PCI)
(Bridge) 13 are mounted.

The CPU 11 executes various programs under the control of the OS. The CPU 11 is, for example, a CPU chip “Pentium” manufactured by Intel Corporation of the United States,
Alternatively, the company's "MMX technology Pentium" may be used.

The L2-cache 12 is a high-speed operation memory for absorbing the time for the CPU 11 to access the main memory 22. Very limited codes and data frequently accessed by the CPU 11 are temporarily stored in the L2-cache 12. The L2-cache 12 generally has 1
The above-described SRAM (static RAM) chip is configured, and its storage capacity is, for example, 512 KB.

The host-PCI bridge 13 is connected to the CPU 1
Processor bus 14 and PCI directly connected to external pins
This is a circuit for interconnecting with a bus 21 (described later). The CPU 11 can perform I / O access to each I / O device via the bridge 13. The host-PCI bridge 13 of this embodiment further includes a main memory 2
2 for controlling the memory access operation to memory 2.
Controller, processor bus 14 and PCI bus 2
And a data buffer for absorbing a difference in data transfer rate between the two. Host-PCI bridge 13
Is sometimes called the "North Bridge."

The basic operating frequency generated by the clock oscillator in the planar card 20 is, for example, about 66 MHz. On the other hand, the CPU 11 sets the internal operating frequency to 233 MHz, which is 3.5 times the basic operating frequency, for example. For this reason, the CPU card 10 consumes approximately 10 W of power during normal operation, and is a major heat source in the system 100. In this embodiment, the CPU card 1
0 is effectively cooled by a cooling system (see FIG. 2) described later. Note that the CPU card 10 includes an identifier for indicating its own type (described later).

The planar card 20 is a main circuit board constituting the system 100 on which various I / O controllers (described later) and the like are mounted. The planar card 20
It communicates with the bridge circuit 13 on the CPU card 10 via the PCI bus 21 and the memory bus 23.

At the other end of the memory bus 23, a main memory 22 is provided. The main memory 22 has a CP
It is used as a read area for the execution program code of U11 or as a work area for writing processing data of the execution program. The execution program referred to here includes a basic input / output system (BIOS) for operating various I / O devices in addition to the OS,
Various application programs are included.

The main memory 22 typically contains one or more D
A RAM (dynamic RAM; for example, SDRAM (synchronous DRAM)) chip is used. The main memory 22 is composed of a basic memory 22a and two DIMs.
This is a DIMM card mounted on an M (Dual Inline Memory Module) socket 22b. The capacity of the basic memory 22a is, for example, 32 MB, but the capacity of the main memory 22 can be increased up to 256 by adding a DIMM card.
MB.

PCI (Peripheral Component Interconn)
ect) The bus 21 is of a type capable of relatively high-speed data transfer (bus width 32/64 bits, maximum operating frequency 33/66 MHz, maximum data transfer rate 132/264).
MBps). The PCI bus 21 functions as a local bus, and in addition to the host-PCI bridge 13 described above,
Various PCI devices such as a video card 50, a multimedia card 60, a card bus controller 32, and a PCI-ISA bridge 31 are connected. It should be noted that the PCI architecture originated from a proposal by Intel Corporation of the United States, and realizes a so-called PnP (plug and play) function.

The video card 50 is a subsystem that provides a display function to the system 100, and is a video card.
It includes a controller 51 and a VRAM 52. The video controller 51 is a dedicated controller chip for actually processing a drawing command from the CPU 11, and temporarily writes the processed drawing information into the VRAM 52, reads out the drawing information from the VRAM 52, and reads out the drawing information from the VRAM 52 (for example, a liquid crystal display) 53. Is output as drawing data. Video card 50
Is one of the PCI devices, and the PCI bus 2
1 is connected to the connector.

[0034] The multimedia card 60 is a subsystem that provides multimedia functions to the system 100. The multimedia card 60 includes an interface 61 for connecting to the PCI bus 21 and an MP 61
An MPEG chip 62 for reproducing MPEG data encoded by the EG method and an NTSC / PAL decoder 63 for processing drawing data of the NTSC / PAL method
Contains. The multimedia card 60 is a PCI card.
This is one of the devices, and is connected to the PCI bus 21 by a connector.

The card bus controller 32 is a PCI bus controller.
This is a dedicated controller for realizing an interface protocol between the bus 21 and the card bus, and has two card slots 36 and 37 at the other end. Each card slot 36, 37 has a PCMCIA
(Personal Computer Memory Card International Asso
ciation) / JEIDA (Japan Electronic Industry D)
evelopment Association) (for example, "PC
Card Standard 95 ") compliant PC card (not shown) can be inserted.

The PCI-ISA bridge 31 is a circuit for interconnecting the PCI bus 21 and the ISA bus 41. The bridge 31 is sometimes called a “south bridge”. The bridge 31 of this embodiment includes a DMA controller and a programmable interrupt controller (PI
C), programmable interval timer (PI
T), the configuration includes RTC / CMOS. D
The MA controller has I / O without CPU11 intervention.
It is a dedicated controller for executing data transfer between a device (for example, FDD 46 (described later)) and the main memory 22. The PIC is a dedicated controller for executing a predetermined processing program (interrupt handler) in response to an interrupt request (IRQ) from an I / O device. The PIT is a device for generating a timer signal at a predetermined cycle, and its generation cycle is programmable.
The RTC (real time clock) part of the RTC / CMOS measures the current time. Further, the CMOS memory part includes system information such as configuration information (BIOS setting values) of the system 100 and a power-on password.
00 is used to store information essential for safety / security. RTC / CMOS is reserved
It is backed up by a battery (usually a coin battery) so that the system 100 does not lose its timed or stored contents while the power is off.

The PCI-ISA bridge 31 of the present embodiment
Is IDE (Integrated Drive Electronics)
An IDE interface for connecting an external storage device conforming to the standard is also provided. An IDE hard disk drive (HDD) 34 is connected to the IDE cable extended from the IDE interface,
E CD-ROM drive 35 is ATAPI (AT Attac
hment Packet Interface) is connected. Also, IDE
Instead of the CD-ROM drive 35, a DVD (Digita
l Other type of ID like Versatile Disc) drive
An E device (not shown) may be connected.

The bridge 31 of this embodiment has a built-in USB controller for connecting a USB (Universal Serial Bus) bus, which is a general-purpose bus, and has at least one USB port 33. USB
Is a function of plugging and unplugging a new USB device while the power is on (hot plugging function), and a function of automatically recognizing a newly connected USB device and resetting system configuration information (plug and Play function). One USB port is allowed to daisy-chain up to 63 USB devices. Examples of USB devices are a keyboard, a mouse, a joystick, a scanner, a printer, a modem, a display monitor, a tablet, etc. (none of which are shown).

ISA (Industry Standard Architectur)
e) The bus 41 has a lower data transfer rate than the PCI bus (a bus width of 16 bits and a maximum data transfer rate of 4 MB).
ps). The ISA bus 41 functions as a system bus, and includes ISA devices such as an I / O controller 42, an audio controller 43, and a modem card 70, as well as a ROM 44 and a cooling system controller 45.
Devices operating at a relatively low speed are connected.

The I / O controller 42 has a floppy
Drive control of the disk drive (FDD) 46, input / output of serial data through the serial port 47 (S
IO), a peripheral controller for controlling parallel data input / output (PIO) via the parallel port 48. For example, a device having an RS232C interface such as a joystick (not shown) is connected to the serial port 47, and a device having a Centronics interface such as a printer (not shown) is connected to the parallel port 48.

The audio controller 43 is a dedicated controller for inputting and outputting audio signals, and generally has a CODEC function for digitally recording and reproducing audio signals. An audio signal is input from a line input terminal or a built-in microphone (not shown), and an audio signal is output via a line output terminal or a built-in speaker (not shown).

The modem card 70 uses the system 100 for handling digital signals as a general public line (PSTN: Public Switched Telephone Network) as an analog signal transmission medium.
This is a subsystem for connecting to (k), and includes circuit components such as a signal processing circuit (DSP) 71 and a data access arrangement function circuit (DAA) 72. The DSP 71 is for modulating transmission data and demodulating received data. Also, D
The AA 72 is for inputting and outputting data in accordance with a circuit switching standard of each country.

The cooling system controller 45 is a controller for totally controlling the cooling system 200 according to the present embodiment. The cooling system 200 is for suitably cooling the CPU card 10 (described above), which is a main heat source of the system 100, and details of the cooling operation will be described later.

The cooling system controller 45 is preferably a one-chip microcontroller "H8 / 3437" manufactured by Hitachi, Ltd. This IC has a RAM, ROM, eight analog input pins, a timer, and sixteen digital input / output pins in addition to a 16-bit processor, and its operation is programmable. The cooling system controller 45 of the present embodiment includes the cooling system 2
In addition to the control function of 00, it is programmed to have a function of controlling input / output operations of the keyboard 81 and the pointing device (mouse) 82.

The system ROM 44 is a group of codes (BIOS: Basic Input / Output System) for input / output operation of each hardware such as the keyboard 81 and the FDD 46.
And a non-volatile memory for permanently storing a self-diagnosis test program (POST) executed when the power is turned on.

The so-called personal computers currently on the market
The computer will perform well as the computer system 100 shown in FIG. Computer system 100 may be a personal computer, a notebook computer, a palmtop computer, a workstation, a mainframe computer, or a supercomputer. Alternatively, computer system 100 may be another type of computer system, for example, a network server.

In order to configure the computer system 100, many electric circuits and the like other than those shown in FIG. 1 are required. However, since these are well known to those skilled in the art and do not constitute the gist of the present invention,
It is omitted in this specification. Also, it should be noted that only some of the connections between the hardware blocks in the drawings are shown in order to avoid complication of the drawings.

B. Configuration of Cooling System FIG. 2 schematically illustrates a configuration of a cooling system 200 according to the present embodiment. The cooling system 200 is provided inside the housing of the system 100 in order to appropriately suppress a rise in temperature due to heat generation in the computer system 100. More preferably, the cooling system 200
Is provided in the immediate vicinity of the CPU card 10 which is a main heat source. Hereinafter, this will be described.

As shown in the figure, the cooling system 200 has a cooling fan 201 and a fan controller 202 for rotating the fan 201 as main components in addition to the cooling system controller 45 described above.

The fan controller 202 has a driving power supply voltage of 5 V, and generates a rotational force of the fan 201 while the driving power is supplied. The CPU card 10 which is a heat source of the system 100 is provided in the middle of the airflow generated by the rotation of the fan 201. Therefore, the rotation of the fan 201 causes the CPU
The atmosphere around the card 10 is exchanged, and a cooling effect substantially proportional to the rotation speed is provided.

The fan controller 202 generates two rotation pulse signals each time the fan 201 makes one rotation, and is supplied to the cooling system controller 45 as FAN_PULSE. However, the rotation pulse signal is valid only when the drive power supply to the fan controller 202 is ON. Such fans
An example of the controller 202 and the fan 201 is UDQFC5E01 manufactured by Kyushu Matsushita Electric Co., Ltd.

On the other hand, the cooling system controller 45
Receives the FAN_PULSE signal and
It has an N_ON signal at its output. The FAN_ON signal is input to the base terminal of the digital transistor Tr2. The collector of the transistor Tr2 is connected to the base terminal of the power transistor Tr1, and the emitter of the transistor Tr2 is grounded.

When the FAN_ON signal is at a high level, the power transistor Tr1 is turned on, that is, the driving power of the fan controller 202 is turned on, while the FAN_O signal is turned on.
When N goes low, the drive power supply is turned off. Further, by repeating the high / low output of the FAN_ON signal, an intermediate fan rotation speed can be created by using the inertia of the rotor of the fan 201. Therefore, the cooling system controller 45
_ON signal is output by PWM (Pulse Width Modulation) and the duty ratio of the
1 can be controlled.

The cooling system controller 45
Is a thermistor 204 mounted on the CPU card 10
By reading the value of the voltage drop, the ambient temperature T
Can be measured.

FIG. 3 shows the cooling system 200 viewed from another side. The cooling system 200 acquires the identifier of the CPU card 10 and obtains the optimum rotational speed φ _opp.
2 illustrates the structure for obtaining

The planar card 20 includes various types of CPUs.
Has the character shared between cards. On the other hand, the CPU card 10 includes a CPU 11 and a bridge circuit 1 mounted therein.
Although the three types are defined, the amount of heat generated by the CPU card 10 differs depending on the type of the CPU 11, the operating frequency and the like. Therefore, according to the type of the CPU card 11 currently accepted by the planar card 20, that is, the identifier,
The optimum rotation speed φ _opp of the fan 201 is determined.

The cooling system controller 4 of this embodiment
Reference numeral 5 reads the identifier of the CPU card 10 using, for example, an ID read signal line having a width of 3 bits.

The cooling system controller 45
Is provided with an optimum value table storing the optimum rotation speed φ _opp for each CPU card. This optimum value table is written in the built-in ROM of the controller chip 45, for example. Further, each entry of the optimum value table stores two types of _high speed optimum rotation speed φ _{opp / high} for a relatively _high temperature and low speed optimum rotation speed φ _{opp / low} for a relatively low temperature. . The cooling system controller 45 refers to the entry corresponding to the read identifier and refers to the corresponding high-speed optimum rotation speed and low-speed optimum rotation speed (further, the initial duty ratio of the FAN_ON signal for realizing each optimum rotation speed). Are registered in the built-in RAM.

The cooling system controller 45 controls the operation of the cooling system 200 (ie, the rotation of the fan 201) in accordance with the program code written in its own built-in ROM. However, details of the operation characteristics of the cooling system controller 45 will be described in section C.

C. Until cooling operations preceding has been described a hardware configuration of a computer system 100 and cooling system 200 embodying the present invention. In this section, the operation of the present invention will be described together with the operating characteristics of the cooling system 200.

The cooling system 200 of this embodiment has three operation modes: a fan-off mode, a low-speed rotation mode, and a high-speed rotation mode.

In the fan-off mode, the CPU card 1
1 is a state in which the temperature is sufficiently low and cooling, that is, the rotation of the fan 201 is not required.

In the low-speed rotation mode, the CPU card 1
This is an operation mode that occurs when the ambient temperature T of 0 exceeds a relatively low threshold temperature T _th1 , and a sufficient cooling effect can be obtained by rotating the fan 201 at a relatively low speed.

In the high-speed rotation mode, the CPU card 1
This is an operation mode that occurs when the ambient temperature T of 0 exceeds a relatively high threshold temperature T _th2 , in which the CPU card 10 is overheated unless the fan 201 rotates at high speed.

The switching between the modes is performed by using a thermistor 20.
The cooling system controller 45 dynamically performs the measurement in accordance with the result of the temperature measurement via the control unit 4. FIG. 4 schematically shows the operation state of the cooling system 200 in the form of a state transition diagram.

FIG. 5 is a flowchart showing a rotation control operation of the fan 201. This operation can be realized by the cooling system controller 45 executing the program code written in its internal ROM. Hereinafter, each step of the operation routine will be described.

In response to the ambient temperature T of the CPU card 10 _{exceeding the} threshold temperature T _th1 or T _th2 , the process enters a processing routine (step S100). The ambient temperature T is measured via the thermistor 204 (described above).

First, the cooling system controller 45
Sets the duty ratio of the FAN_ON signal output to 100% and rotates the fan 201 at full speed (step S
102). And for a predetermined time (for example, 0.5 seconds)
Then, the full rotation is continued and the rotation of the fan 201 is stabilized (step S104).

Next, the duty ratio of the FAN_ON signal output is set to the initial duty ratio corresponding to the current operation mode of the cooling system 200 (Step S106). FIG. 6 illustrates a subroutine executed in step S106.

First, in sub-step S106a, it is determined whether the mode is the fan-off mode. This determination block determines that the ambient temperature T of the CPU card 10 is actually T _th1.
It is carried out depending on whether it falls below. If the mode is the fan-off mode, the process jumps to sub-step S106b,
The fan 201 is completely stopped. In this case, FAN_
The ON signal is a low level output, that is, the duty ratio is 0.
%.

On the other hand, if the result of the judgment block S106a is negative, the routine proceeds to sub-step S106c, where it is judged whether or not the low-speed rotation mode is set. This decision block
In practice, the determination is made based on whether the ambient temperature T of the CPU card 10 does not exceed T _th2 . If it is the low-speed rotation mode, the process proceeds to sub-step S106d, where the initial duty ratio in the low-speed rotation mode is set. The initial duty ratio is read from the optimum value table corresponding to the identifier of the CPU card 10 (described above).

If the result of the decision block S106c is negative, it is assumed that the mode is the high-speed rotation mode. In this case, the process proceeds to sub-step S106e to set the initial duty ratio in the high-speed rotation mode. The initial duty ratio is read from the optimum value table corresponding to the identifier of the CPU card 10 (described above).

Returning to FIG. 5, the subsequent steps will be described. Between steps S108 to S122, the number of rotations of the fan 201 is sampled N times (for example, 10 times) based on the duty ratio set in step S106 or the duty ratio adjusted in step S126 (described later).

In step S108, the initial value zero is substituted for i, and in step S110, i is incremented by one.

Next, in step S112, the duty ratio set in step S106 or step S12
The FAN_ON signal is PWM-outputted according to the duty ratio adjusted in 6. Further, steps S114 to S1
At 18, a timer is set to a predetermined value (for example, 5 seconds),
The sampling period of the rotation speed of the fan 201 is determined. However, if the operation mode of the cooling system 200 changes due to the fluctuation of the ambient temperature T of the CPU card 10 before the time-out occurs, the process exits from the branch Yes of step S116 and proceeds to the preceding step S116.
Return to 106.

When the timer times out, the rotation speed φ _i of the fan 201 is measured (step S12).
0). As described above, the fan controller 202 outputs two pulse waves per one rotation of the fan 201. Therefore, assuming that the interval between two consecutive pulse waves of the FAN_PULSE signal input to the cooling system controller 45 is I [sec], 60 / (2 × I) [rpm] is the measured rotation speed φ.
_i .

Next, in step S122, it is determined whether or not the number of times of measurement of the number of revolutions has reached N times. Upon completion of the measurement of N times, in step S124, the calculating an average rotational speed phi _a.

Next, in step S126, the fan 2
The duty ratio is adjusted so that the number of revolutions of 01 approaches the optimal number of revolutions φ _opp defined in the optimal value table. The duty ratio may be adjusted according to, for example, Table 1 below. According to the table, when the average rotation speed φ _a is lower than the optimum rotation speed φ _opp by 100 [rpm], the duty ratio is added by 4, and the average rotation speed φ _a is changed to the optimum rotation speed φ.
If it exceeds the _opp by 75 [rpm], the duty ratio may be subtracted by 4. Note that the PWM timer of the cooling system controller 45 according to the present embodiment sets the duty ratio from 0% to 100% to 1/250 (that is, 0.4%).
% Resolution).

[0079]

[Table 1]

Table 1 is stored in the built-in ROM of the cooling system controller 45, for example. Table 1 is created based on, for example, experimental values, and is not limited to real values in the table. Alternatively, the next duty ratio may be calculated using a predetermined correction formula without using a table.

After adjusting the duty ratio in step S126, the process returns to step S108 again, and the same processing as described above is repeated.

D. The present invention has been described in detail with reference to specific embodiments. However, it is obvious that those skilled in the art can modify or substitute the embodiment without departing from the spirit of the present invention. For example, the present invention can be applied to various cordless devices such as facsimile devices, mobile wireless terminals and cordless telephones, electronic organizers, video cameras, and various electric and electronic devices such as word processors. In short, the present invention has been disclosed by way of example, and should not be construed as limiting. In order to determine the gist of the present invention, the claims described at the beginning should be considered.

[0083]

As described above in detail, according to the present invention,
An excellent cooling system for an electronic device including a heat generating component can be provided.

Further, according to the present invention, it is possible to provide an excellent cooling system of a type that dissipates heat generated in the device by rotation of a fan.

Further, according to the present invention, it is possible to provide an excellent cooling system in which the fan is appropriately rotated according to the amount of heat generated.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a hardware configuration of a typical personal computer (PC) 100 suitable for realizing the present invention.

FIG. 2 is a diagram schematically illustrating a configuration of a cooling system 200 according to the present embodiment.

FIG. 3 is a diagram showing a cooling system 200 including a CPU card 1;
FIG. 3 is a diagram showing a structure for obtaining an identifier of 0 and obtaining an optimum rotation speed.

FIG. 4 is a state transition diagram schematically showing an operation state of the cooling system.

FIG. 5 is a diagram showing a rotation control operation of a fan 201 in the form of a flowchart.

FIG. 6 is a diagram showing a subroutine executed in step S106 in the flowchart shown in FIG. 5;

[Explanation of symbols]

10 CPU card, 11 CPU, 12 L2-cache, 13 Host-PCI bridge, 14 Processor bus, 20 Planar card, 21 PCI bus, 22 Main memory, 23 Memory bus , 31
... PCI-ISA bridge, 32 ... Card bus controller, 33 ... USB port, 34 ... HDD, 35 ... C
D-ROM drive, 36, 37 ... card slot,
41: ISA bus, 42: I / O controller, 43 ...
Audio controller, 44 ... System ROM, 4
5: Cooling system controller, 46: FDD, 47
... Serial port, 48 ... Parallel port, 50 ...
Video card, 51 ... Video controller, 52 ...
VRAM, 53: display, 60: multimedia card, 61: interface circuit, 62: MPE
G chip, 63 NTSC / PAL decoder, 70 modem card, 71 DSP, 72 DAA, 81 keyboard, 82 pointing device, 100
Computer system, 200 cooling system, 20
1 ... Fan, 202 ... Fan controller, 204 ...
Thermistor.

Continued on the front page (72) Inventor Eiji Tsukamoto 1623-14 Shimotsuruma, Yamato City, Kanagawa Prefecture Inside the Yamato Office of IBM Japan, Ltd. (72) Inventor Tetsushi Nakamura 1623 Shimotsuruma, Yamato City, Kanagawa Prefecture Address 14 Inside the Yamato Office of IBM Japan, Ltd.

Claims (5)

[Claims] In a cooling system for an electronic device including a heat-generating component, the fan is rotated by (a) a cooling fan and (b) a driving power supply, and measurement data on the number of rotations of the fan is output. A cooling system comprising: a fan controller; and (c) a cooling system controller that corrects a duty ratio of drive power supply on / off supplied to the fan in accordance with measurement data on the rotation speed of the fan. 2. A cooling system for an electronic device including a heat-generating component, wherein the fan is rotated by (a) a cooling fan and (b) a driving power source, and outputs measurement data on the number of revolutions of the fan. A fan controller, and (c) a cooling system controller that corrects a duty ratio of a drive power supply on / off supplied to the fan according to the measurement data on the fan speed so that the fan speed reaches an optimum value. And a cooling system comprising: 3. A cooling system for an electronic device including a heat-generating component, wherein the fan is rotated by (a) a cooling fan and (b) a driving power source, and measurement data on the number of revolutions of the fan is output. A fan controller, (c) a temperature measuring device for measuring a temperature around the heat-generating component, and (d) determining an optimum rotation speed of the fan based on the measured temperature, and obtaining the optimum rotation speed via the fan controller. A cooling system for correcting a duty ratio of drive power supply on / off supplied to the fan according to a difference between the actual rotation speed of the fan and the optimum rotation speed.
And a controller. 4. A cooling system for an electronic device including a heat-generating component, wherein the fan is rotated by a cooling fan and a driving power supply, and measurement data on the number of rotations of the fan is output. A fan controller, and (c) an identifier provided on the heat generating component;
(D) an optimum value table describing the relationship between each identifier of the heat-generating component and the optimum rotational speed of the fan; Rotation speed determining means for determining,
(F) a cooling system controller that corrects a duty ratio of drive power supply on / off supplied to the fan according to a difference between the actual rotation speed of the fan and the optimum rotation speed obtained via the fan controller; A cooling system comprising: 5. A cooling system for an electronic device including a heat-generating component, wherein the fan is rotated by a cooling fan and a driving power source, and measurement data relating to the rotation speed of the fan is output. A fan controller, and (c) an identifier provided on the heat generating component;
(D) An optimum value table describing a relationship between each identifier of the heat-generating component and an optimum rotation speed of the fan, wherein each table entry stores two or more optimum rotation values corresponding to two or more threshold temperatures. (E) the optimal value table
A temperature measuring device for measuring the temperature around the heat-generating component,
(F) rotation speed determining means for determining a current optimum rotation speed according to the identifier of the heat-generating component and the measured temperature; and (g) the actual rotation speed and the optimum rotation speed of the fan obtained via the fan controller. A cooling system controller that corrects a duty ratio of drive power supply on / off supplied to the fan according to the difference of the cooling system controller.