JP2011199205A - Electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the manufacturing cost of an electronic apparatus and to make the electronic apparatus compact by decreasing the number of cooling fans though sufficiently cooling respective devices that the electronic apparatus includes.SOLUTION: The electronic apparatus including a first heat generating device and a second heat generating device which operate while generating heat, is provided with a first temperature detector of detecting the temperature of the first heat generating device and a second temperature detector of detecting the temperature of the second heat generating device. Then the temperature of the first heat generating device detected by the first temperature detector and the temperature of the second heat generating device detected by the second temperature detector are used to perform variable control over the rotating speed of a fan motor of the cooling fan configured to blow cooling air to the first heat generating device and the second heat generating device.

Description

  The present invention relates to an electronic device including an electronic component such as a CPU that operates with heat generation, and a cooling fan that sends cooling air to the electronic component.

  Devices such as a CPU (Central Processing Unit) and a power supply unit that generate heat during operation are mounted on general electronic devices such as personal computers, and each device must be installed in order to maintain normal operation of the device. It is necessary to operate within each rated temperature. Therefore, when an electronic device is provided with a device that generates a large amount of heat and natural air cooling alone is not sufficient, the device must be cooled by some method. As a conventional cooling method, a method of providing a power supply fan that blows air to a power supply unit that generates a particularly large amount of heat among devices and exhausts air inside the housing of the device to the outside of the housing is the mainstream.

  In recent years, CPU performance has increased and the amount of heat generated by the CPU has increased. Accordingly, electronic devices are often provided with a CPU fan that blows air to a heat sink provided in the CPU in addition to the power supply fan.

  The rotational speed of the CPU fan may be variably controlled according to the temperature detected by the thermistor provided in the CPU from the viewpoint of noise countermeasures and power saving. For example, Patent Document 1 discloses a method of taking control of a PWM (Pulse Width Modulation) system and variably controlling the rotational speed of a CPU fan in accordance with the temperature of the CPU.

  When a plurality of fans such as a power supply fan and a CPU fan are provided in an electronic device, there arises a problem that the manufacturing cost of the device increases. In addition, since it is necessary to provide a space for installing each fan in the casing of the electronic device, it is difficult to reduce the size of the device.

  On the other hand, if the number of fans provided in the electronic device is reduced, it becomes impossible to use a high-performance device that generates a large amount of heat, so that the performance of the electronic device is significantly reduced.

  The present invention has been made based on the above-described circumstances, and an object of the present invention is to reduce the number of cooling fans while sufficiently cooling each device included in the electronic apparatus, to reduce the manufacturing cost of the apparatus, and to the apparatus Is to reduce the size.

  An electronic apparatus according to an aspect of the present invention includes a first heat generating device and a second heat generating device that operate with heat generation, a cooling fan that sends cooling air to the first heat generating device and the second heat generating device, and the cooling fan Detected by the first temperature detecting means, the first temperature detecting means for detecting the temperature of the first heat generating device, the second temperature detecting means for detecting the temperature of the second heat generating device, and the first temperature detecting means. Control means for variably controlling the rotational speed of the fan motor using the detected temperature and the temperature detected by the second temperature detecting means.

  According to the present invention in which the above measures are taken, it is possible to reduce the number of cooling fans while sufficiently cooling each device included in the electronic device, thereby reducing the manufacturing cost of the device and reducing the size of the device. .

The schematic diagram which shows the internal structure of the electronic device in one Embodiment. FIG. 2 is a schematic diagram illustrating an AA cross section of the electronic apparatus illustrated in FIG. 1. The block diagram which shows the control circuit of the same electronic device. 6 is a flowchart showing the operation of a fan controller provided in the electronic apparatus. The figure for demonstrating the PWM control example of the fan motor with which the same electronic device is provided. The schematic diagram which shows the internal structure of the electronic device in a modification. The schematic diagram which shows the internal structure of the electronic device in a modification.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
The electronic device 1 described below includes a personal computer, a server device connected to a network, an office computer used for issuing various forms, a POS (Point Of Sales) terminal used for accounting work in a store, and the like. The various electronic devices are included.

[Device structure]
First, the device structure of the electronic device 1 will be described.
FIG. 1 is a schematic diagram illustrating a state in which the inside of a housing of the electronic device 1 is viewed from above, and FIG.
1 and FIG. 2 is a housing, which has a mesh-like intake port 2a on one side wall thereof, and a mesh-like exhaust port on a side wall opposite to the side wall provided with this intake port 2a. 2b is provided. In the housing 2, a power supply unit 3 (first heat generating device), an engine board 4 disposed above the power supply unit 3, an upper surface side of the engine board 4 and intake air from the power supply unit 3. The CPU 5 (second heat generating device) mounted on the side of the port 2a, the cooling fan 6 provided in the vicinity of the exhaust port 2b, and various devices (not shown) necessary for controlling the electronic device 1 are accommodated. ing.

  The power supply unit 3 conforms to, for example, the ATX standard, converts an input from a commercial AC power supply or a power supply such as a battery into a plurality of DC outputs of a predetermined voltage, and supplies it to each part of the electronic device 1.

  The engine board 4 is composed of, for example, a motherboard conforming to the ATX standard, and in addition to the CPU 5, on-board devices such as a chip set, a ROM (Read Only Memory), a RAM (Random Access Memory), and various controllers are mounted. Yes.

  The CPU 5 functions as a main control unit of the electronic device 1 and executes various calculations under the control of a BIOS (Basic Input / Output) or an OS (Operating System). Each device including the CPU 5 mounted on the engine board 4 operates by receiving power supply from the power supply unit 3.

  Note that a heat sink (not shown) in which a plurality of heat radiation fins are provided to increase the surface area is attached to the power supply unit 3 and the CPU 5 in order to improve air cooling performance.

  When the cooling fan 6 rotates, an air flow from the intake port 2a toward the exhaust port 2b is generated as shown by the broken line arrows in FIGS. That is, the outside air taken in from the intake port 2a is blown as cooling air to the CPU 5 and the power supply unit 3 and is exhausted from the exhaust port 2b after taking heat from the heat sink provided in the CPU 5 and the power supply unit 3.

[Control circuit]
A control circuit related to driving of the cooling fan 6 is shown in FIG.
The control circuit includes a CPU side circuit Y composed of parts mounted on the engine board 4 and the CPU 5, and a power source side circuit composed of each part provided in the power supply unit 3 and a fan motor 6M that rotates the cooling fan 6. And X.

  The power supply side circuit X includes the fan motor 6M, a thermistor 20 (first temperature detection means) that detects the temperature Tps of the power supply unit 3, and a transistor 21. On the other hand, the CPU side circuit Y includes a fan controller 10 (control means) that outputs a drive signal for the fan motor 6M, a thermistor 11 (second temperature detection means) that detects the temperature Tcpu of the CPU 5, and a BIOS in which the BIOS is stored. A ROM 12 and a transistor 13 are provided.

  The BIOS-ROM 12 stores a BIOS that is a basic operation program of the electronic device 1. The data constituting the BIOS includes a reference temperature Tx used for controlling the rotational speed of the fan motor 6M. This reference temperature Tx is set to a value within the rated temperature at which the power supply unit 3 can operate normally.

  When the fan motor 6M needs to be driven, the fan controller 10 outputs either a drive signal Cpwm for PWM control of the fan motor 6M or a drive signal Cmax for rotating the fan motor 6M at the maximum rotation speed. . The drive signal Cpwm is a signal composed of a pulse having a constant magnitude output at a predetermined period, and is output to the transistor 13. The drive signal Cmax is a continuous signal having a constant magnitude and is output to the transistor 21.

  The transistors 13 and 21 convert the drive signals Cpwm and Cmax input from the fan controller 10 into drive currents for rotating the fan motor 6M, respectively, and output them to the fan motor 6M.

  A power supply voltage Vcc is connected to the fan motor 6M, which is driven at a timing when a drive current is input from one of the transistors 13 and 21, and rotates the cooling fan 6.

  In the control circuit having such a configuration, when the drive signal Cpwm is output from the fan controller 10, the rotational speed of the fan motor 6M changes according to the duty ratio of the drive signal Cpwm. Here, the duty ratio is the ratio of the pulse width to the period T of the drive signal Cpwm. On the other hand, when the drive signal Cmax is output from the fan controller 10, the fan motor 6M rotates at the maximum rotation speed Rmax.

[Fan motor control]
The control of the fan motor 6M by the fan controller 10 will be specifically described.
When the operation power is turned on to the electronic device 1 by pressing a power-on button provided on the housing 2 or the like, the CPU 5 performs diagnosis and initialization of each unit under BIOS control. After the initialization or the like is completed, the fan controller 10 executes processing according to the flowchart shown in FIG. 5 to control the fan motor 6M.

  In this process, first, the fan controller 10 acquires the temperature Tps detected by the thermistor 20 of the power supply side circuit X (step S1). Subsequently, the fan controller 10 reads the reference temperature Tx from the BIOS-ROM 12, and compares the temperature Tps with the reference temperature Tx (step S2).

  When the temperature Tps is lower than the reference temperature Tx (“Tps <Tx” in step S2), the fan controller 10 responds to the temperature Tcpu so that the temperature Tcpu of the CPU 5 detected by the thermistor 11 does not exceed the rated temperature of the CPU 5. The drive signal Cpwm having the duty ratio is output to PWM control the fan motor 6M (step S3).

FIG. 4 shows the relationship between the temperature Tcpu of the CPU 5 and the rotational speed of the fan motor 6M in the PWM control in step S3. When the temperature Tcpu detected by the thermistor 11 is lower than the start temperature T1, which is the starting point of the duty ratio increase, the fan controller 10 generates a duty ratio drive signal Cpwm that rotates the fan motor 6M at the minimum rotational speed Rmin. , Output to the transistor 13. Eventually, after the temperature Tcpu reaches the start temperature T1, the fan controller 10 increases the duty ratio of the drive signal Cpwm to be generated in proportion to the temperature Tcpu. At this time, the rotational speed of the fan motor 6M increases as the duty ratio of the drive signal Cpwm increases. Thereafter, when the duty ratio of the drive signal Cpwm reaches 100%, the fan motor 6M rotates at the maximum rotation speed Rmax.
Thus, in the process of step S3, the rotational speed of the fan motor 6M is variably controlled according to the temperature Tcpu of the CPU 5.

  On the other hand, when the temperature Tps is equal to or higher than the reference temperature Tx in the process of step S2 (“Tps ≧ Tx” of step S2), the fan controller 10 outputs the drive signal Cmax to the transistor 21 and causes the fan motor 6M to operate at the maximum rotational speed. Rotate at Rmax (step S4). Accordingly, sufficient cooling air is blown to the power supply unit 3, so that the temperature Tps of the power supply unit 3 does not exceed the rated temperature.

  The fan controller 10 executes steps S1 to S4 until the power supply to the electronic device 1 is stopped.

  As described above, the electronic apparatus 1 according to the present embodiment changes the rotational speed of the cooling fan 6 using the temperature Tcpu of the CPU 5 and the temperature Tps of the power supply unit 3 so that each of the power supply unit 3 and the CPU 5 has a rated temperature. Cool so as not to exceed. By doing in this way, the number of cooling fans provided in the electronic device 1 can be reduced, and the manufacturing cost of the electronic device 1 can be reduced. Moreover, since the installation space for one cooling fan can be omitted, the electronic device 1 can be reduced in size.

  Further, the fan motor 6M is driven by PWM control according to the temperature Tcpu of the CPU 5 until the temperature Tps of the power supply unit 3 exceeds the reference temperature Tx. Therefore, it is possible to keep the noise such as the driving sound of the fan motor 6M and the wind noise of the cooling fan 6 and the driving power of the fan motor 6M as low as possible.

  Further, the CPU 5 is arranged on the upstream side of the cooling air with respect to the power supply unit 3 that generates a larger amount of heat than the normal CPU 5. Therefore, it is possible to prevent a situation in which the ambient temperature of the CPU 5 rises due to heat generated by the power supply unit 3 and the CPU 5 is overheated. Even if the ambient temperature of the power supply unit 3 rises due to the heat generated from the CPU 5 disposed on the upstream side of the cooling air, the fan motor 6M is operated at the maximum rotational speed when the power supply unit 3 exceeds the reference temperature Tx. Since it is driven at Rmax, the power supply unit 3 is not overheated above the rated temperature.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying constituent elements without departing from the scope of the invention in the implementation stage. Specific examples of modifications are as follows.

(1) In the above embodiment, the power supply unit 3 and the CPU 5 are arranged with the engine board 4 interposed therebetween. However, the arrangement positions of the power supply unit 3 and the CPU 5 are not limited to this. For example, as shown in FIG. 6, the power supply unit 3 may be housed in a case 8 fixed to the upper inner wall of the housing 2, and the CPU 5 may be mounted on the upper surface side of the engine board 4 disposed below the power supply unit 3. Even when the arrangement positions of the power supply unit 3 and the CPU 5 are changed as described above, the same effects as those of the configuration disclosed in the embodiment are obtained.

(2) Further, in order to efficiently cool the CPU 5 by the cooling fan 6, an exhaust duct 9 extending from a part of the cooling fan 6 to the vicinity of the CPU 5 may be provided as shown in FIG. In this way, since the airflow is generated around the CPU 5 as the cooling fan 6 rotates, the CPU 5 is efficiently cooled.

(3) In the embodiment, the example in which the power supply unit 3 and the CPU 5 are devices to be cooled by the cooling fan 6 has been described. However, the present invention may be applied by selecting other devices that generate heat during operation, such as a hard disk drive, various memories, and various controllers, as devices to be cooled. When the device to be cooled is changed and implemented, temperature detecting means such as a thermistor is provided for each device to be cooled, and the rotational speed of the fan motor 6M is variably controlled using each detected temperature. .

(4) In the above embodiment, the fan motor 6M is rotated at the maximum rotation speed Rmax when the temperature Tps of the power supply unit 3 exceeds the reference temperature Tx. However, even if the rotational speed Rmax is not the maximum, the power supply unit 3 and the CPU 5 may rotate the fan motor 6M at a constant rotational speed set within a range not exceeding the rated temperature, or may be variable according to the temperature Tps. The fan motor 6M may be rotated at a rotation speed set to.

(5) In the above embodiment, when the temperature Tps of the power supply unit 3 is lower than the reference temperature Tx, the rotational speed of the fan motor 6M is PWM controlled according to the temperature Tcpu. However, the rotational speed of the fan motor 6M may be variably controlled by another control method that is not PWM control, or the fan motor 6M is controlled at a constant rotational speed set within a range in which the CPU 5 does not exceed the rated temperature. It may be rotated.

  As described above, various modifications can be made as to how the rotational speed of the fan motor 6M is controlled using the temperatures Tps and Tcpu.

  In addition, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment.

  DESCRIPTION OF SYMBOLS 1 ... Electronic device, 2 ... Housing, 3 ... Power supply unit, 4 ... Engine board, 5 ... CPU, 6 ... Cooling fan, 6M ... Fan motor, 10 ... Fan controller, 11, 20 ... Thermistor, Tps ... Power supply unit temperature , Tcpu ... CPU temperature, Tx ... reference temperature, Rmax ... maximum rotation speed

JP 2007-157770 A

Claims (6)

A first heat generating device and a second heat generating device operating with heat generation;
A cooling fan for sending cooling air to the first heat generating device and the second heat generating device;
A fan motor that rotationally drives the cooling fan;
First temperature detecting means for detecting the temperature of the first heat generating device;
Second temperature detecting means for detecting the temperature of the second heat generating device;
Control means for variably controlling the rotational speed of the fan motor using the temperature detected by the first temperature detection means and the temperature detected by the second temperature detection means;
An electronic device comprising:   The first heat generating device is a power supply unit that supplies operating power to each part of the electronic device, and the second heat generating device is a CPU that operates by receiving power supply from the power supply unit. The electronic device according to claim 1.   The electronic device according to claim 2, wherein the CPU is disposed upstream of the cooling air generated by the rotation of the cooling fan with respect to the power supply unit.   4. The control device according to claim 1, wherein the control unit rotates the fan motor at a maximum rotation speed when a temperature detected by the first temperature detection unit exceeds a predetermined reference temperature. 5. Or the electronic device according to 1 above.   The control means rotates the fan motor at a rotational speed corresponding to the temperature detected by the second temperature detection means when the temperature detected by the first temperature detection means is lower than the reference temperature. The electronic device according to claim 4. When the temperature detected by the first temperature detecting means is lower than the reference temperature, the control means outputs a PWM signal having a duty ratio corresponding to the temperature detected by the second temperature detecting means,
The electronic apparatus according to claim 4, wherein the fan motor rotates at a rotation speed corresponding to a duty ratio of a PWM signal output from the control unit.

Images