JPH09151896A - Electric fan driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To drive an electric fan for the prescribed time even after turning off a main power switch so as to continue to cool heating electric parts without using a timer switch by connecting a capacitor of large capacitance serving as an auxiliary power supply, between a power supply and the electric fan, in parallel to the electric fan. SOLUTION: A DC power supply A serving as a power supply is connected to an electric fan M, and an electric double-layer capacitor C serving as an auxiliary power supply is connected between the DC power supply A and the electric fan M, in parallel to the electric fan M. A main power switch SW is turned on to start up electrical equipment and to drive the electric fan M simultaneously so as to start charging the electric double-layer capacitor C. When the main power switch SW is turned off upon terminating the use of the electrical equipment, electric power is supplied to the electric fan M from the electric double-layer capacitor instead of the DC power supply A. Even after turning off the main power switch SW, the electric fan M can thereby be driven for the prescribed time, so that heating parts can be continuously cooled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive device for an electric fan, and more particularly to a drive device for an electric fan provided with an auxiliary power supply for driving an air-cooling electric fan for heat-generating electric parts for a predetermined time even after the main power supply is turned off. It relates to the device.

[0002]

2. Description of the Related Art For example, halogen lamps of overhead projectors (OHPs), CPUs such as switching power supplies and personal computers, and electric (electronic) parts such as power transistors generate heat when energized, and if left unattended, they generate their own heat. There is a risk of breakdown.

Although heat sinks are usually attached to these heat-generating components, if heat radiation is not sufficient by itself, it is necessary to blow air by an electric fan to forcibly cool it. FIG. 4 exemplifies the simplest drive circuit of the electric fan. According to this, an electric fan M of this type is generally provided with a power source of an electric device in which the electric fan M is mounted, usually via a plug P. Connected to a commercial power source
It is driven by the power supply A. The DC power source A converts alternating current into direct current and supplies it to the secondary side, and a primary power switch SW is provided on the primary side. Although not shown, the DC power source A is shared with other circuits of the device.

According to this, the electric fan M is driven at the same time when the main power switch SW is turned on to start up the equipment. On the contrary, when the main power switch SW is turned off, the electric fan M is stopped at the same time. Since the cooling is stopped in the state where the heat of the heat-generating electric component is not sufficiently dissipated, the temperature becomes high temporarily, which may cause a failure or shorten the life of the component.

Therefore, as shown in FIG. 5, for example, a two-contact changeover switch is used as the main power switch SW, one contact a of which is directly connected to the DC power supply A, and the other contact b is predetermined. There is a device which is connected to the DC power supply A through a timer switch T which is turned off after a lapse of time.

According to this, by connecting the main power switch SW to the contact a side, a predetermined power is supplied from the DC power source A to start the electric fan M, but with the end of use of the device. When the main power switch SW is switched to the contact b side, the timer switch T starts timing, and the timer switch T turns off after a lapse of a predetermined time thereafter.

That is, even if the main power switch SW is turned off, the electric fan M does not immediately stop, but the electric fan M stops after a predetermined time has elapsed by the timer switch T, so that the heat-generating electric components are continuously cooled during that time. Become.

[0008]

However, since the timer switch T is expensive, its use is not preferable in terms of cost. Further, since the plug P cannot be pulled out while the timer switch T is in operation, when leaving the seat during the operation, there is a concern that it will stop after that. On the contrary, when the outlet is unintentionally or intentionally unplugged, the electric fan M is turned off at that time, and the same problem as in the conventional example of FIG. 4 occurs.

The present invention has been made in order to solve such a conventional problem, and an object thereof is to use a timer switch without using a main power switch even after the main power switch is turned off or the outlet is pulled out. It is an object of the present invention to provide a drive device for an electric fan that can reliably drive the electric fan for a predetermined time thereafter.

[0010]

In order to achieve the above-mentioned object, the invention according to claim 1 is connected to a predetermined power source,
In a drive device for an electric fan for air-cooling heat-generating electric parts, a large capacitance capacitor as an auxiliary power supply is connected in parallel to the electric fan between the power supply and the electric fan. I am trying.

According to this, the main power switch is turned on, and the capacitor is charged while the electric fan is being driven. Then, when the main power switch is turned off, electric power is supplied from the capacitor to the electric fan, and thus the electric fan is driven for a predetermined time even after the main power switch is turned off.

In this case, it is preferable that the capacitor is an electric double layer capacitor. In particular, the wound type having a structure in which activated carbon is rolled on the surface of each of a pair of aluminum foils and wound with a separator interposed therebetween has a large space capacitance because of its small size and large capacitance.

Further, in the invention of claim 3, between the power supply and the capacitor, a reverse current blocking for preventing the discharge current of the capacitor from flowing back to the power supply and other circuit side sharing the same power supply. It is characterized in that a diode for use is connected. According to this, the discharge current of the capacitor is supplied only to the electric fan without flowing back to the other circuit side.

Further, the invention of claim 4 is characterized in that a thermal relay which is turned on / off according to the heat generation temperature of the heat generating electric component is connected between the capacitor and the electric fan. In this case, as described in claim 5, as the thermal relay,
A bimetal switch that is inexpensive and easily available is preferable.

According to this, the electric fan is driven only when the temperature of the heat-generating electric component reaches a certain temperature or higher, that is, when the temperature reaches a temperature at which cooling is required. Therefore, for example, if the equipment is started up, the main power switch is turned off immediately after that, and the equipment is no longer used, and the temperature of the heat-generating electrical components is not so high, the electric fan will not be driven and the annoying blowing noise will occur. Can be stopped within the minimum time.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Next, for better understanding of the technical idea of the present invention, the embodiments shown in FIGS. 1 and 2 will be described. In these drawings, the same reference numerals are used for the same parts as the conventional example described above.

As shown in FIG. 1, the electric fan M
Is connected to a DC power source A as a power source as in the conventional case, but in this case, an electric double layer capacitor C as an auxiliary power source is connected to the electric fan M between the DC power source A and the electric fan M. Connected in parallel.

In addition, a backflow between the DC power source A and the electric double layer capacitor C, which prevents the discharge current of the electric double layer capacitor C from sneaking into the DC power source A and other circuits sharing the same power source. A blocking diode D is connected.

According to this, at the same time when the main power switch SW is turned on to start up the device, the electric fan M is driven and charging of the electric double layer capacitor C is started. Then, when the main power switch SW is turned off due to the end of use of the device, electric power is supplied from the electric double layer capacitor C to the electric fan M instead of the DC power source A, whereby the electric fan M is kept for a predetermined time. It is driven continuously.

According to the present invention, the main power switch SW
Even if the plug P of the device is inadvertently or intentionally pulled out while the power is on, the electric fan M is driven for a predetermined time by the same drive current as when the main power switch SW is turned off. Is supplied.

Here, two winding type electric double layer capacitors C having a rating of 2.5V and 4.7F are connected in parallel to the electric fan M (rated driving voltage 5V), and 12
Since the V4A switching power supply (not shown) has been cooled, this will be described with reference to the temperature change graph of FIG. Note that the alternate long and short dash line in the figure shows this embodiment, and the solid line shows the conventional example in which the electric fan M is stopped at the same time when the main power switch SW is turned off.

According to this, while the main power switch SW is turned on and the electric fan M is rotated, the temperature of the switching power supply during operation is maintained at about 45 ° C. in both the embodiment and the conventional example. When the main power switch SW is turned off from this state, the switching power supply is also turned off. However, in the case of the conventional example, the electric fan M is also stopped, so the temperature of the switching power supply is as shown by the solid line in the figure due to its latent heat. The temperature once increased to over 50 ° C, and then gradually decreased due to natural heat dissipation.

On the other hand, in the case of the embodiment, the electric fan M is driven by the electric double layer capacitor C for about 4 minutes even after the main power switch SW is turned off.
The temperature of the switching power supply decreased as shown by the alternate long and short dash line.
After that, the electric fan M stopped due to the completion of the discharge of the electric double layer capacitor C, and the temperature of the switching power supply rose once due to its latent heat, but at most 4
It was about 2 to 43 ° C., and then gradually decreased due to natural heat dissipation.

In this way, when the temperature of the switching power supply was measured 10 minutes after the main power switch SW was turned off, it was about 36 ° C. in the case of the embodiment, whereas
In the case of the conventional example, it was 42 ° C.

Next, a second embodiment of the present invention shown in FIG. 2 will be described. In the second embodiment, in addition to the configuration of the above embodiment, a thermal relay SR that is turned on / off according to the heat generation temperature of the heat generating electric component is incorporated. This thermal relay SR is an electric double layer capacitor C
Is connected between the electric fan M and the electric fan M, and specifically, a bimetal switch is used.

According to this, when the temperature of the heat-generating electric component has not reached the predetermined temperature, the thermal relay SR is off, so that even if the main power switch SW is turned on, the electric fan M is not immediately driven. The electric fan M is driven when the temperature of the heat-generating electric component reaches a predetermined temperature and the thermal relay SR is turned on.

Even when the main power switch SW is turned off,
When the temperature of the heat-generating electric component has not reached the predetermined temperature, the thermal relay SR is off, so that the drive current is not supplied from the electric double layer capacitor C to the electric fan M.

Therefore, according to the second embodiment, for example, the main power switch SW is turned on to start the device, but the operation is terminated immediately after that, and the temperature of the heat-generating electric component has not reached the predetermined temperature. In this case, the electric fan M is not driven, and the generation of blowing noise can be minimized.

In each of the above embodiments, the main power switch S
Although W is arranged on the primary side of the DC power source A, unlike this, the main power switch SW may be provided on the secondary side of the DC power source A. The main power switch SW may be arranged on both sides.

Further, although the switching power supply is taken as an example of the heating electric component in the above embodiment, the present invention is not limited to this. For example, a halogen lamp of an overhead projector (OHP), a CPU such as a personal computer, and a power source. It may be applied to the cooling of transistors, and further MO drives (magneto-optical disk drives) and the like.

[0031]

As described above, according to the present invention, the following effects can be obtained. That is, according to the invention described in claim 1, the main power switch is turned on, the capacitor is charged while the electric fan is driven, and when the main power switch is off, electric power is supplied from the capacitor to the electric fan. As a result, the electric fan is driven for a predetermined time even after the main power switch is turned off, and the heat-generating electric components are continuously cooled without using the timer switch.

In this case, according to the invention of claim 2 in which the capacitor is an electric double layer capacitor, in particular, by using a wound type capacitor, an auxiliary power source having a small capacitance but a large capacitance can be obtained. You can

A reverse current blocking diode is connected between the power source and the capacitor to prevent a discharge current of the capacitor from flowing backward to the main power source and another circuit side sharing the power source. According to the third aspect of the invention, the discharge current of the capacitor is supplied only to the electric fan without flowing back to the other circuit side, and the electric fan is driven reliably.

According to the invention of claim 4, further comprising a thermal relay connected between the condenser and the electric fan, the thermal relay being turned on / off according to the heat generation temperature of the heat generating electric component, That is, the electric fan is driven only when the temperature reaches the required cooling level, and the annoying air blowing noise can be stopped within the minimum time.

[Brief description of the drawings]

FIG. 1 is a schematic circuit diagram showing a first embodiment according to the present invention.

FIG. 2 is a schematic circuit diagram showing a second embodiment according to the present invention.

FIG. 3 is a temperature change graph comparing the cooling effects of the heat-generating electric components according to the first example and the conventional example.

FIG. 4 is a schematic circuit diagram showing a first conventional example.

FIG. 5 is a schematic circuit diagram showing a second conventional example.

[Explanation of symbols]

 A DC power supply SW Main power switch M Electric fan C Electric double layer capacitor (auxiliary power supply) D Reverse current blocking diode SR Thermal relay

Claims (5)

[Claims] 1. A drive device for an electric fan, which is connected to a predetermined power supply and air-cools a heat-generating electric component, wherein between the power supply and the electric fan, a static electricity as an auxiliary power supply is provided in parallel with the electric fan. A drive device for an electric fan, to which a capacitor having a capacitance is connected. 2. The drive device for an electric fan according to claim 1, wherein the capacitor is an electric double layer capacitor. 3. Between the power source and the capacitor,
3. The electric fan according to claim 1, further comprising a reverse current blocking diode connected to prevent the discharge current of the capacitor from flowing backward to the power source and another circuit side sharing the power source. Drive. 4. A thermal relay, which is turned on / off according to the heat generation temperature of the heat generating electric component, is connected between the capacitor and the electric fan, and the thermal relay is connected to the electric fan. The drive device for the electric fan according to item 1. 5. The drive device for an electric fan according to claim 4, wherein the thermal relay is a bimetal switch.