JPH06335285A - Electronic device - Google Patents

Abstract

PURPOSE:To achieve low level noise and vibration by providing a circuit that, after a cooling fan has started at a voltage required for its start-up, lowers the voltage to a level required for the normal rotation of the cooling fan. CONSTITUTION:When power is supplied, a voltage is applied to the base of a transistor 202 through a capacitor 209, and the transistor 202 is turned on. When the transistor 202 is turned on, another transistor 201 is turned on as well, and a cooling fan 210 is supplied with power of starting voltage of 5V through the transistor 201. A resistor 204 and the capacitor 209 forms an integrating circuit, and the voltage applied to the base of the transistor 202 is lowered with time until the transistor 202 is turned off. When the transistor 202 is turned off, the transistor 201 is turned off as well, and the voltage is applied to the cooling fan 210 through a resistor 206. This makes it possible to control the speed of cooling fan 210 rotation, and thus reduce noise and vibration to any desired level.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compact electronic device such as a laptop computer or a notebook computer.

[0002]

2. Description of the Related Art In recent years, due to the high performance of CPUs, high density mounting of boards, increase of memory capacity, downsizing and high capacity of disk devices, and thinning of display devices typified by liquid crystals, they have been used in personal applications. The spread of compact computers that can be done is remarkable. The trend toward compactness is
In the future, it is expected that the same will be applied to electronic equipment such as larger-scale computers such as workstations. On the other hand, as the operating frequency increases, the heat generation density inside the housing of electronic equipment increases, so that a cooling fan for forcibly discharging heat is often installed inside the housing. There is. However, if a cooling fan is provided in the housing, noise and vibration are generated by the cooling fan, and various improvements have been made to solve the problem in electronic equipment that is becoming more compact.

An example of the configuration of the above-described conventional electronic device will be described below with reference to the drawings. FIG. 3 is a block diagram of a cooling fan driving means of a conventional electronic device. In FIG. 3, 301 is a voltage supply unit that supplies a rated operating voltage to the cooling fan, and 302 is the voltage supply unit 301.
It is a cooling fan driven by the voltage supplied by.

[0004]

However, in the above-described structure, the cooling fan 302 is always supplied with the same voltage, so that the cooling fan 302 always operates at the voltage for generating the torque required for starting the cooling fan. As a result, the noise and vibration generated by the electronic equipment have been increased more than necessary.
Moreover, in order to suppress large noises and vibrations, measures have been taken with soundproof materials, anti-vibration rubber, etc. However, with the miniaturization of the electronic equipment, the electronic equipment has been used more often closer to the user, and the noise and vibration problems have become more serious. Has reached the limit because there is no more space in the housing. In view of the above problems, the present invention provides a circuit that lowers the supply voltage to a voltage required for steady rotation of the cooling fan after supplying the voltage required to start the cooling fan, thereby reducing noise and vibration. In addition, the present invention provides a highly reliable electronic device.

[0005]

In order to achieve the above object, the electronic equipment of the present invention supplies the voltage necessary for starting the cooling fan, and then, it is necessary for the cooling fan to rotate steadily. A circuit having a circuit for reducing the supply voltage to a voltage is provided between the voltage supply unit and the cooling fan.

[0006]

Therefore, according to the electronic equipment of the present invention, the operating voltage supplied to the cooling fan is
The voltage required to generate the minimum torque required for the cooling fan to start rotating at startup, and the minimum torque required to maintain the rotation after the cooling fan starts rotating. Since the voltage required to operate the cooling fan is set, the noise and vibration generated by the cooling fan during normal use can be reduced to a low level. Furthermore, since it is not necessary to use an additional member for preventing noise and vibration, the device can be further downsized.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an electronic equipment device of the present invention will be described below with reference to the drawings. FIG. 1 shows a cooling fan driving means of an electronic device according to an embodiment of the present invention. FIG. 2 is a circuit diagram showing a schematic configuration of a voltage adjusting unit and a cooling fan unit in the cooling fan driving means of FIG. In FIG. 1, 101 is a voltage supply unit that supplies a rated operating voltage to the voltage adjustment unit, 102 is a voltage adjustment unit that adjusts the voltage supplied by the voltage supply unit 101 to an arbitrary level, and then supplies the voltage to the cooling fan, Reference numeral 103 is a cooling fan driven by the voltage supplied by the voltage adjusting unit 102.

In FIG. 2, 201 is a transistor, 2
02 is a transistor for driving the transistor 201, 2
03 is a diode that discharges the electric charge remaining in the capacitor 209 when the power is cut off and makes the circuit operate normally when the power is turned on again. 204 is the resistor 205 and the capacitor 20.
A resistor forming an integrating circuit together with 9, 205 a resistor forming an integrating circuit together with a resistor 204 and a capacitor 209, 206 a resistor determining a drop amount of a supply voltage to the cooling fan, 207
Is a resistor for stabilizing the base potential of the transistor 201, 208 is a resistor for limiting the base current of the transistor 201, 209 is a capacitor that forms an integrating circuit with the resistors 204 and 205, and 210 is supplied with a voltage by this circuit. It is a cooling fan.

In the cooling fan driving means configured as described above, when a cooling fan whose voltage required for starting is 5 V is used, a voltage is applied to the base of the transistor 202 through the capacitor 209 when the power is turned on and the base of the transistor 202 is applied. Turns on. When the transistor 202 is turned on, the transistor 201 is also turned on, and a 5V starting voltage is applied to the cooling fan 210 through the transistor 201. Further, the resistor 204 and the capacitor 209 form an integrating circuit, and the voltage applied to the base of the transistor 202 decreases with time, so that the transistor 202 is turned off and accordingly the transistor 201 is also turned off. Therefore, the cooling fan 2
The voltage across 10 is applied through resistor 206. That is, by appropriately adjusting the value of the resistor 206, the voltage supplied to the cooling fan can be lowered, and the rotation speed of the cooling fan can be controlled.

[0010]

As described above, the electronic device apparatus of the present invention is
After the voltage required to start the cooling fan is supplied, a circuit that reduces the supply voltage to the voltage required for the cooling fan to rotate steadily is provided between the voltage supply unit and the cooling fan, so that the cooling Since the rotation speed of the cooling fan can be controlled, noise and vibration generated by the cooling fan can be reduced to an arbitrary level. Further, since no additional soundproofing material or vibration damping material is required, there is an effect that further downsizing of the electronic device can be realized.

[Brief description of drawings]

FIG. 1 is a block diagram showing a cooling fan driving means of an electronic device according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing a schematic configuration of a voltage adjusting unit and a cooling fan of the electronic device apparatus according to the embodiment of the present invention.

FIG. 3 is a block diagram showing a cooling fan driving means of a conventional electronic device.

[Explanation of symbols]

101, 301 ... Voltage supply unit, 102 ... Voltage adjustment unit, 103, 21
0, 302 ... Cooling fan, 201, 202 ... Transistor, 20
3 ... Diode, 204, 205, 206, 207, 208, ... Resistor,
209 ... Capacitor.

Claims (1)

[Claims] 1. An electronic device apparatus comprising a circuit for supplying a voltage required for starting a cooling fan and then lowering the supply voltage to a voltage required for steady rotation of the cooling fan.