JPH07231058A - Cooling equipment for electronic apparatus - Google Patents

Abstract

PURPOSE:To keep constant the temperature of a d.c. power supply and a load apparatus by controlling the speed of cooling fan revolution based on the output voltage of an integrating circuit, which receives control signals for the control of transistor operation from the voltage control circuit in the d.c. power supply and integrates the signals, and the input voltage of the d.c. power supply. CONSTITUTION:The calorific values of a d.c. power supply 10 and a load apparatus are proportional to output current, and calorific value is proportional to a product of duty factor D and input voltage Ei. The magnitude of duty factor D is obtained by integrating PWM signals (switching control signals), which control the on and off of a transistor 3, by means of an integrating circuit 21. Therefore, the speed of the revolution of a cooling fan 14 is controlled according to values obtained by multiplying values from the integration of the PWM signals by values of input voltage Ei. Thus the speed of cooling fan 14 revolution is controlled at the same time as load current fluctuates. This makes it possible to increase the cooling capability before the temperature of the d.c. power supply 10 or the load apparatus 11 rises.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention predicts a change in heat generation amount in advance in a cooling device for cooling a DC power supply device or a load device whose heat generation amount changes with time because the load current changes with time. However, by controlling the temperature so that it is always constant, and cooling the entire equipment most efficiently, the reliability of the equipment to be cooled can be improved, and this is an economical cooling device for electronic equipment. It is about.

[0002]

2. Description of the Related Art Examples of conventional cooling devices for electronic equipment are shown in FIGS. In FIG. 6, 1 is a DC power supply,
2 is a transformer, 3 is a switching transistor, 4
Is a transistor drive circuit for driving the transistor 3,
5 is a rectifying diode, 6 is a choke coil for smoothing, 7
Is a smoothing capacitor, 8 is a voltage control circuit, 9 is a current detection resistor, 10 is a DC power supply device, 11 is a load device whose load current changes with time, and 12 is attached to the DC power supply device 10 or the load device 11. Further, 13 is a temperature control circuit, 14 is a cooling fan, and 15 is a drive circuit for driving the cooling fan 14.

Further, in FIG. 7, reference numerals 16 and 17 denote a first DC power supply apparatus and a second DC power supply apparatus, which have the same circuit as the DC power supply apparatus 10, and 18 and 19 denote the load apparatus 1.
The first load device and the second load device in which the load current changes with time as in the case of 1, and 20 is a flow rate regulator that determines the distribution of the cooling air flow rate by the maximum heat generation ratio of each DC power source or load device. is there.

FIG. 8 shows an outline of the operation of the conventional device shown in FIG. 6, where (a) shows a change in load current, (b) a voltage waveform diagram showing a signal from the temperature control circuit 13, E is a diagram showing the rotation speed of the cooling fan 14, and E is a diagram showing the temperature of the mounting portion of the temperature sensor 12.

Next, the operation of the conventional device shown in FIG. 6 will be described. The DC power supply device 10 is a switching-type power supply that is most often used at present, and the transistor 3 is turned on / off to supply a pulse current to the primary side of the transformer 2 so that power is transmitted to the secondary side of the transformer 2. To be done. The power generated on the secondary side of the transformer 2 is rectified by the rectifier diode 5, stored in the smoothing capacitor 7 via the smoothing choke coil 6, and supplied to the load device 11 as a predetermined DC voltage. The voltage control circuit 9 is a capacitor 7
The voltage across the capacitor 7 is detected, and a signal is sent to the transistor drive circuit 4 to widen the ON width of the transistor 3 when the voltage drops and narrow the ON width when the voltage rises, so that the voltage across the capacitor 7 is constantly Works to stay constant,
When the current flowing through the current detection resistor 8 exceeds the rating of the transistor 3, the operation of the transistor 3 is stopped. The temperature sensor 12 is the DC power supply device 10.
Or it is attached to the most heat generating part of the load device 11,
When the temperature becomes higher than a predetermined temperature, the temperature control circuit 13 operates the cooling fan 14 or sends a signal to the drive circuit 15 to increase the rotation speed. The air volume of the cooling fan 14 is set so that the DC power supply device 10 or the load device 11 can be sufficiently cooled even when the load device 11 consumes the maximum current. Therefore, as shown in FIG. 8A, when the load current consumed by the load device 11 changes with time, the temperature signal detected by the temperature sensor 12 becomes as shown in FIG. 8E, and the cooling fan 14 operates. The interval to be set becomes shorter as the load current increases. The temperature control circuit 13 sends the voltage waveform shown in A of FIG. 8 to the motor drive circuit 15, and the rotation speed of the cooling fan 14 is varied as shown in FIG. Therefore, the DC power supply device 10 and the load device 11 are overheated or cooled in accordance with the operation cycle of the cooling fan 14, so that excessive thermal stress is applied. Further, the operating points of the cooling fans 14 change due to differences in the characteristics of the temperature sensors 12, the mounting method, the position, etc. Therefore, it was necessary to adjust all the operating points. Furthermore, the cooling fan 1
Each time No. 4 operates, noise is given to the peripheral device, which often causes malfunction of the peripheral device.

Further, in an electronic device using a plurality of DC power supply devices and load devices as shown in FIG. 7, cooling air from the cooling fan 14 is supplied to the DC power supply devices and the load devices by the flow rate controller 20. The DC power supply unit and the load unit are cooled by distributing the heat generation amount ratio at the time of maximum heat generation of the device. For this reason, it is necessary to use the cooling fan 14 having a large cooling capacity so that all the devices can be cooled.
Current consumption is less than the rating, or conversely the load device 19
Even if the current consumption of the fan is less than the rated value, the cooling fan 1 is always provided with an air volume that can cool the maximum heat generation amount.
4 had to be operated, could not be miniaturized, and was not economically good.

[0007]

Since the cooling device for electronic equipment using the conventional circuit is constructed as described above,
A large cooling fan was required even when the DC power supply or load device was overheated or the amount of heat generated was small. There is a problem that electronic devices and load devices malfunction, and there is a problem that reliability and economic efficiency are poor.

The present invention has been made to solve the above problems, and predicts a change in the amount of heat generated by a DC power supply device or a load device in advance, and installs a cooling fan so that the temperature is always constant. By controlling and continuously operating the cooling fan, noise generated when switching between operation and stop is eliminated, and further, the cooling fan is efficiently cooled.

[0009]

A cooling device for electronic equipment according to the present invention predicts a heat generation state of a DC power supply device or a load device from a switching operation control signal of the DC power supply device and an input power supply voltage or current transmission signal. By controlling the rotation speed of the cooling fan and the flow rate of the cooling air distributed to each DC power supply device or load device, the cooling fan can be efficiently controlled so that the temperature is always constant. Moreover, it is provided with a control circuit and a flow rate controller for continuously controlling the cooling fan so as to eliminate noise generated each time the cooling fan operates and stops.

[0010]

The cooling device for electronic equipment according to the present invention prolongs the life of the electronic equipment by predicting a change in the heat generation amount of the DC power supply device or the load device in advance and cooling the temperature so that the temperature is always constant. Efficiently cooling with a small cooling fan and eliminating noise generated each time the cooling fan operates / stops, it is possible to suppress malfunction of electronic equipment and cool electronic equipment more economically. it can.

[0011]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 1 to 11, 14, and 15 are the same as those of the above-described conventional device and circuit, 21 is an integrating circuit for integrating the PWM signal from the control circuit 9, and 22 is proportional to the voltage value after integration. It is a temperature control circuit that controls the rotation speed of the cooling fan 14.

Further, FIG. 2 is a diagram for explaining the operation of the present invention, and shows one when the input voltage is constant for convenience of explanation. The symbols used in FIG. 2 are the same as the symbols shown in FIG. 8 for explaining the operation of the conventional device, and the newly added symbol c is the voltage signal after integrating the PWM signal in the integrating circuit 21. .

The operation will be described in detail below with reference to the drawings. In the configuration of FIG. 1, when the current consumption of the load device 11 increases as shown in FIG. 2, the voltage across the smoothing capacitor 7 in the DC power supply device 10 decreases, and the voltage control circuit 9 causes the ON width of the transistor 3 to decrease. In order to widen it, a PWM signal as shown in FIG. 2B is sent to the transistor drive circuit 4. Now, the ratio of the number of turns of the secondary winding to the number of turns of the primary winding of the transformer 2 is N, the on-time of the transistor 3 versus the switching period (hereinafter referred to as duty) D, the output power P _o , the input voltage Is E _i , the power conversion efficiency of the DC power supply device 10 is η, the output current is I _o , and the output voltage is E _o , the output power P _o can be expressed as in “Equation 1”.

[0014]

[Equation 1]

Further, P _L can be represented by the "number 2" when the heating value of the DC power supply 10 and P _L, the load device 1
The heat generation amount of 1 is the same as the output power when the power output from the load device 11 is substantially zero, and can be represented by P _o .

[0016]

[Equation 2]

Since the output voltage E _o is constant, the heat generation amount of the DC power supply device 10 and the load device 11 is proportional to the output current I _o , as can be seen from the above "expression 1" and "expression 2". ,
It can be seen from "Equation 1" that the heat generation amount is proportional to the product of the duty D and the input voltage E _i . Since the magnitude of the duty D is expressed by integrating the PWM signal that controls the on / off of the transistor 3, the duty D is cooled by the value obtained by multiplying the integrated value of the PWM signal by the input voltage E _i times. If the rotation speed of the cooling fan 14 is controlled, the rotation speed of the cooling fan 14 is controlled at the same time when the load current fluctuates, and the cooling capacity is increased before the temperature of the DC power supply device 10 or the load device 11 rises. DC power supply 1
It can be seen that the temperature of 0 and the load device 11 can be kept constant. Further, as shown in FIG. 1, since the temperature is not directly detected by the temperature sensor, there is no error caused by the characteristics and mounting method of the temperature sensor, and it is not necessary to carry out 100% test adjustment. Since the signal is used as it is, it can be realized with a simple circuit configuration.

Example 2. FIG. 3 shows an embodiment in which the cooling fan 14 is controlled by a current detection signal from the DC power supply device 10 in the electronic device cooling device shown in the embodiment of FIG. The transistor 3 is turned on / off in synchronization with the PWM signal from the control circuit 9,
The current detection signal obtained from both ends of the current detection resistor 8 connected to the emitter side of the transistor 3 has a waveform similar to that in FIG. However, when the amplitude of the waveform a is I _p , I _p can be expressed by “Equation 3”.

[0019]

[Equation 3]

As can be seen from "Equation 3", since I _p and I _o are in proportion to each other, from "Equation 1" it can be seen that I _p is in proportion to the heat generation amount P _L. Therefore, the current detection signal is integrated by the integrating circuit 21, and the value obtained by multiplying the current detection signal by a constant multiple is used.
It can be easily imagined that the same effect as that of the first embodiment can be obtained by controlling the rotation speed of No. 4. In FIG. 3, the switching type DC power supply described in the first embodiment is used for convenience of explanation, but since the cooling fan can be controlled by the current detection signal, the present invention can be applied to a series type regulator or battery. Further, in FIG. 3, the current detection resistor 8 is connected to the emitter side of the transistor 3 to detect the switching current of the transistor 3, but the current detection resistor 8 is connected to the smoothing choke coil 6 in series and output. The same effect can be obtained by directly detecting and using the current I _o , and it is easily imagined that the same effect can be obtained by substituting the current detecting resistor 8 with a current detecting transformer or another element. it can.

Example 3. FIG. 4 is a diagram showing an example in which a plurality of DC power supply devices 10 and load devices 11 shown in the first or second embodiment are used. In FIG. 4, reference numerals 1, 14 to 20 are the same as those of the conventional device and circuit described above, and reference numerals 23, 24 are integrals for integrating the control signals (PWM signal or current detection signal) from the DC power supply devices 16 and 17, respectively. A circuit, 25 is a flow rate control circuit that receives signals from the integrating circuits 23 and 24 and controls the flow rate distribution of the cooling air from the cooling fan 14, and 26 has wings in the flow path of the cooling air, and the angle of the wings can be changed. By doing so, the flow rate regulator capable of adjusting the flow rate distribution of the cooling air to the DC power supply devices 16 and 17 or the load devices 18 and 19, and 27 is a control signal from the flow rate control circuit 25 and a blade from the flow rate regulator 26. Is an amplifier for operating and controlling the wing of the flow rate regulator 26 by comparing and amplifying the angle signal indicating the angle. Now, in the flow rate controller 26, the blade placed in the flow path for sending the cooling air to the DC power supply device 16 or the load device 18 is placed in the flow path for sending the cooling air to the DC power supply device 17 or the load device 19. When the blade is B and the angle of the blade positioned so as to block the cooling air is zero, the angles of the blades are θ _A and θ _B , respectively.
(However, 0 ≦ θ _A , θ _B ≦ 90 °) Flow rate control circuit 25
Receives the integrated value of the control signal (PWM signal or current detection signal) from the DC power supply devices 16 and 17 from the integrators 20 and 21, and compares the signals with each other to determine which DC power supply device has a larger output current. Is output and sent to the amplifier 27 as a voltage signal. The amplifier 27 sends a drive signal for rotating the blades to the flow rate regulator 26 so that there is no difference between the angle signals of the blades A and B whose flow rate is adjusted by the flow rate regulator 26 and the signal from the flow rate control circuit 25. .

FIG. 5 shows the internal structure of the flow rate regulator 26 and the amplifier 27. Hereinafter, FIG. 5 will be described in more detail. In FIG. 5, 28 and 29 are potentiometers and 3
0 and 31 are motors for driving wings A and B, 3
2 and 33 are amplifiers for comparing and amplifying the signal from the potentiometer and the signal from the flow rate control circuit 25 shown in FIG.
4 is a cooling duct. The flow rate control signal from the flow rate control circuit 25 shown in FIG.
When the flow rate to (provisionally A system) is maximized (θ _A is 9
At 0 °), the signal voltage V _A sent to the amplifier 32 is output as the maximum voltage V. Further, when the flow rate to the DC power supply device 17 and the load device 19 (provisionally referred to as B system) is maximized (when θ _B is 90 °), the signal voltage V _B sent to the amplifier 33 is set to the maximum voltage V. Output. The potentiometers 28 and 29 are connected to the motors 30 and 31, respectively, and send the signal voltage V to the amplifier 27 if the angle between the blades A and B for adjusting the flow rate is 90 °, and 0 if the angle is 0 °.
To the amplifier 27. Now, when the angle of the wing A is θ _A , the angle of the wing B is θ _B , and the cross-sectional areas of the flow passages are S, the areas S _A and S _{B through which} the cooling air can pass are respectively expressed by "," Can be represented by "Equation 5".

[0023]

[Equation 4]

[0024]

[Equation 5]

Assuming that the air pressure in the cooling duct 34 is uniform, when the heat generation amount of the A system is M% at the maximum heat generation and the heat generation amount of the B system is L% at the maximum heat generation, the flow rate control circuit When the flow rate control signals V _A and V _B from 25 are controlled as shown in "Equation 6", it is understood from "Equation 4" and "Equation 5" that the areas S _A and S _B are M: L. Therefore, the flow rate ratio sent to the A system and the B system becomes M: L, and the A system and the B system can be cooled uniformly.

[0026]

[Equation 6]

Therefore, in the electronic equipment in which the heat generation amounts of the A system and the B system are not maximized at the same time, the cooling fan 14
Is a cooling fan that operates at a constant rotation speed, no matter how the ratio of heat generation changes, as long as it has the ability to cool the maximum heat generation of the sum of the heat generation of A system and the heat generation of B system. It can be cooled by changing the flow distribution of the cooling air.

[0028]

As described above, according to the present invention, the current consumption of the load device changes and the heat generation amount of the DC power supply device or the load device changes, so that the temperature of the equipment is not increased or is too cold. In addition, it is possible to realize a highly reliable cooling device for electronic devices that can freely control the cooling capacity and can always keep the temperature of the DC power supply device and the load device constant. In addition, since the temperature is not directly detected by the temperature sensor, there is no error caused by the characteristics of the temperature sensor or the mounting method. Therefore, 100% test adjustment is performed, so an economical cooling device for electronic equipment is obtained. be able to.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram of a cooling device for an electronic device according to a first embodiment of the present invention.

FIG. 2 is a diagram for explaining the operation of each unit in the first embodiment of the present invention.

FIG. 3 is a circuit configuration diagram of a cooling device for an electronic device according to a second embodiment of the present invention.

FIG. 4 is a circuit configuration diagram of a cooling device for an electronic device according to a third embodiment of the present invention.

FIG. 5 is a diagram illustrating a flow rate adjuster of a cooling device according to a third embodiment of the present invention.

FIG. 6 is a circuit configuration diagram showing a conventional cooling device for electronic equipment.

FIG. 7 is a circuit configuration diagram showing a case where a plurality of conventional cooling devices for electronic devices are used.

FIG. 8 is a diagram for explaining the operation of the conventional cooling device for an electronic device.

[Explanation of symbols]

 1 DC power supply 2 Transformer 3 Transistor 4 Transistor drive circuit 5 Rectifying diode 6 Smoothing choke coil 7 Smoothing capacitor 8 Current detection resistor 9 Voltage control circuit 10 DC power supply device 11 Load device 12 Temperature sensor 13 Temperature control circuit 14 Cooling fan 15 Drive Circuit 16 1st DC Power Supply Device 17 2nd DC Power Supply Device 18 1st Load Device 19 2nd Load Device 20 Flow Regulator 21 Integrating Circuit 22 Control Circuit 23 Integrating Circuit 24 Integrating Circuit 25 Flow Control Circuit 26 Flow controller 27 Amplifier 28 Potentiometer 29 Potentiometer 30 Motor 31 Motor 32 Amplifier 33 Amplifier

Claims (3)

[Claims] 1. A transistor for switching a current from a DC power supply through a transformer, a transistor drive circuit for driving the transistor, and a rectifier diode connected to the secondary side of the transformer for rectifying the current.
The choke coil and the capacitor for smoothing the current from the rectifying diode and the voltage between the terminals of the capacitor are controlled to be a predetermined voltage, and the current flowing in the transistor is detected and the current exceeding the rated value does not flow. A DC power supply device comprising a voltage control circuit for controlling the transistor drive circuit, a load device connected in parallel with the capacitor and having a load current that changes with time, and a cooling device for the DC power supply device or the load device. A cooling fan and a drive circuit for driving the cooling fan, wherein the integration circuit receives and integrates a control signal for controlling the operation of the transistor from a voltage control circuit of the DC power supply device. And a DC power supply and a load based on the output voltage of the integration circuit and the input voltage value of the DC power supply. Predicting the amount of heat generated by the location, a control circuit for controlling the rotation speed of the cooling fan, the cooling device of an electronic apparatus, characterized by comprising between said voltage control circuit and the drive circuit. 2. A current detection signal for detecting a current flowing through a switching transistor and controlling a DC power supply device so that the current does not flow above a predetermined current value,
A control circuit for predicting the heat generation amount of the DC power supply device and the load device and controlling the rotation speed of the cooling fan is provided between the current detection resistor and the drive circuit. Item 2. A cooling device for an electronic device according to item 1. 3. A cooling fan that uses a plurality of DC power supply devices and load devices and cools the DC power supply device or the entire load device, and cooling air from the cooling fan for each DC power supply device or the load device. In a cooling device for electronic equipment composed of a flow rate controller that distributes at the ratio of the maximum heat generation amount, predicting the heat generation amount of each DC power supply device and the load device from the control signal from the voltage control circuit of each DC power supply device, A flow rate control circuit for controlling the distribution of the cooling air from the cooling fan in accordance with the heat generation ratio of each device within a certain time, and a cooling air receiving a signal from the control circuit in the flow path of the cooling air. A cooling device for an electronic device, comprising a flow rate adjuster for varying the distribution of the flow rate.