JPH09186279A - Cooler for lsi - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to drive a fan without necessity of a power source and a temperature sensor at all, to automatically regulate the number of revolutions of the fan in accordance with the heating temperature of an LSI and to effectively cool the LSI. SOLUTION: The cooler for individually cooling LSI mounted on a circuit board comprises an evaporating part 2 mounted on the radiating surface of an LSI case 1, a condensing part 3 connected to the evaporating part via pipes 41, 42, operating fluid 5 for pressure reducing an inner space for connecting the evaporating, condensing parts and pipes to substantially vacuum state to be sealed in the space, a fan 7 rotatably mounted at the outside of the condensing part, and a turbine 6 disposed in the condensing part to rotate the fan by the flow of the fluid.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LSI cooling device, and more particularly to a local cooling device for individually cooling heat-generating LSIs.

[0002]

2. Description of the Related Art An LSI used for a CPU or the like must be cooled so as to keep its temperature below a specified temperature in order to guarantee its life and gate delay time. When the amount of heat generated by the LSI is about 10 W or less, the entire circuit board on which this LSI is mounted is cooled by a motor fan, so that the LS
It was possible to keep I below the specified temperature. However, recent LSIs tend to increase the amount of heat generated as the degree of integration increases, and the heat generated by some LSIs mounted on the circuit board may exceed 10W.

Therefore, conventionally, an LSI having a large heat generation amount is provided with a dedicated motor fan to individually cool the LSI having a large heat generation amount. As such a device for individually cooling some LSIs, for example, US Patent 5,
In 335 and 722, it is proposed that the motor fan for individually cooling the LSI is downsized.

[0004]

However, in the above-described conventional LSI cooling device, the power supply voltage of the general LSI is 3.3 to 5 V, whereas the drive voltage of the motor inside the fan is 12 V. ~ 24V, and therefore the LSI
There is a problem in that a power supply and a DC / DC converter that are equivalent to the power supply for operating the circuit board on which is mounted must be provided for cooling the LSI.

Further, in order to keep each LSI at an appropriate temperature, a temperature sensor must be provided for each LSI to electrically control the rotation speed of each motor fan. Furthermore, if a motor fan is provided for each LSI,
There is also a problem that an installation space is required for each motor fan, the size of the entire device is increased, and noise is increased by a plurality of motors.

Although it is possible to drive each motor fan by a power source for operating the circuit board and the like,
With such a configuration, the rotation speed of the fan may be insufficient and the LSI may not be cooled.

It is also conceivable to increase the number of coil turns of the motor for rotating the fan to increase the rotation speed of the fan, but in this case, the noise of the motor becomes large and the current fluctuation and the starting current are increased. Getting bigger,
There is a problem that the operation of the LSI becomes unstable.

Although it is not an LSI cooling device, in Japanese Patent Laid-Open No. 167143/1993, a heat generating portion including a semiconductor laser and a Peltier element for cooling the semiconductor laser, and a heat radiating portion including a fin and a motor fan for cooling the same. There is proposed a semiconductor laser cooling device having a structure in which the Peltier element and the fin are connected by a heat pipe.

According to this structure, the heat generated by the Peltier element is transferred to the fins by the heat pipe, and the fins are cooled by the motor fan, so that the heat generated by the Peltier element is removed. Can be removed.

However, even in this semiconductor laser cooling device, since the motor fan is driven by the power source, it is not possible to solve the above-mentioned problems of the conventional LSI cooling device.

The present invention has been made in view of the above problems, and provides an LSI cooling device capable of effectively cooling an LSI without requiring any power source to drive a fan or control the rotation speed. For the purpose of provision.

[0012]

In order to achieve the above object, an LSI cooling device according to claim 1 is a cooling device for individually cooling an LSI mounted on a circuit board,
An evaporation unit directly or indirectly attached to the heat dissipation surface of the LSI, and a condensation unit connected to the evaporation unit via a pipe;
The continuous internal space of the evaporation part, the condensation part, and the pipe is decompressed to a substantially vacuum state, the working fluid enclosed in the internal space, the fan rotatably attached to the outside of the condensation part, and the inside of the condensation part. And a turbine that is located and rotates the fan according to the flow of the working fluid.

According to this structure, when the LSI generates heat, the heat causes the working fluid in the evaporation section to evaporate. The LSI is cooled to a specified temperature by the movement of heat at this time.

Further, since the working fluid 5 is enclosed in a state close to a vacuum, the vapor flow of the working fluid generated by the heat generation of the LSI is low in pressure from the high pressure evaporation section through the pipe. It flows into the condenser and rotates the turbine to drive the fan. This allows
The condenser is cooled, and the working fluid in the condenser is condensed and returns to liquid. The working fluid that has become liquid is
Gravity flows from the pipe into the evaporator,
It is again used for cooling the LSI.

When the evaporation section is arranged near the fan, or when the condensation section and the side wall of the evaporation section are joined, the LSI blows the air.
Can be cooled indirectly.

According to a second aspect of the present invention, there is provided an LSI cooling device in which the condenser section is provided with fins for receiving the wind of the fan to cool the condenser section. With such a configuration, the condenser can be effectively cooled, and the LSI can be efficiently cooled.

According to a third aspect of the present invention, in an LSI cooling device, a wick that circulates the working fluid condensed on the condenser section side to the heat generating section is provided on inner walls of the evaporator section, the condenser section and the pipe. It is a formed structure.

With this structure, the working fluid condensed in the condensing section can be forced to flow into the evaporating section by the capillary phenomenon of the wick. Therefore, gravity for returning the condensed working fluid to the evaporation unit is not necessary, and the degree of freedom of the installation positions of the evaporation unit and the condensation unit can be increased.

According to a fourth aspect of the present invention, there is provided an LSI cooling device in which the evaporation section and the condensation section are vertically stacked. According to such a configuration, the side walls of the condenser and the evaporator can be joined, and the air of the fan can indirectly cool the LSI. Also,
By vertically stacking the evaporating section and the condensing section, the lateral opening space of the cooling device can be widened.

According to a fifth aspect of the present invention, there is provided an LSI cooling device in which the evaporating section and the condensing section are provided laterally.
With such a configuration, it is possible to widen the vertical opening space of the present cooling device.

According to a sixth aspect of the present invention, there is provided an LSI cooling device in which a plurality of the evaporation sections are connected to the condenser section through the pipes, and the LSI is attached to each of the evaporation sections. With such a configuration, it is possible to cool the plurality of LSIs by using the one condenser, the fin, and the fan.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of an LSI cooling device of the present invention will be described below with reference to the drawings. FIG.
2 is a perspective view showing an LSI cooling device according to an embodiment of the present invention, and FIG. 2 is a side sectional view of the LSI cooling device.

The LSI cooling device of this embodiment has a structure in which an evaporating portion and a condensing portion for circulating a working fluid are vertically stacked.

In these drawings, reference numeral 1 denotes an LSI case, which is not shown, but an LSI having a high heat generation density such as a CPU is mounted inside in a face-down manner. This L
A hollow evaporation part 2 is adhered to the heat dissipation surface of the SI case 1, and a hollow condensation part 3 is formed above the evaporation part 2. The evaporator 2 and the condenser 3 are
They are connected via a feed pipe 41 and a return pipe 42.

One end of the feed pipe 41 is connected to the upper side of the evaporation section 2 so that the evaporation flow of the working fluid 5 described later flows in. The other end is opposed to the turbine 6 provided in the condenser 3 and has a nozzle 41a. By forming the nozzle 41a on the other end of the feed pipe 41, the evaporation flow ejected from the nozzle 41a can be accelerated.

On the other hand, one end of the return pipe 42 is connected to the condenser 3
Is connected to the lower side of the evaporator 2 and the other end is connected to the lower side of the evaporator 2 so that the working fluid 5 condensed in the condenser 3 flows into the evaporator 2 by gravity.

The evaporation part 2, the condensation part 3, the feed pipe 41 and the return pipe 42 are made of a material having a good thermal conductivity such as aluminum or copper. Also, L
The SI case 1 and the evaporation part 2 have good thermal conductivity for adhesion.
In addition, an adhesive having flexibility that can absorb a difference in thermal expansion coefficient between the LSI case 1 and the evaporation portion 2, for example, a silicon adhesive or the like is used.

The continuous internal space of the evaporator 2, condenser 3, feed pipe 41 and return pipe 42 is depressurized to a state close to a vacuum, and the working fluid 5 is enclosed therein. The working fluid 5 is generated by the heat generation temperature of the LSI and the evaporation unit 2,
It is determined in consideration of suitability for the material of the condenser 3 and the like. For example, water or alcohol can be used.

The turbine 6 is rotatably provided inside the condenser 3 through a magnetic coupling 8 provided on the upper wall of the condenser 3, and is operated to be ejected from the nozzle 41a of the feed pipe 41. It is configured to rotate by receiving the vapor flow of the fluid 5.

A fan 7 is attached to the rotating shaft of the turbine 6 via the magnetic coupling 8. The fan 7 is driven by the rotation of the turbine 6, sucks outside air, and sends cool air to the upper surface side of the condenser 3.

The magnetic coupling 8 has a structure in which a magnet is supported by a ball bearing in order to reduce the loss of transmission torque due to friction. By using the magnetic coupling 8 as described above, the rotational torque of the turbine 6 can be reliably transmitted to the fan 7 without impairing the vacuum property inside the condenser 3 and the like.

The rotary shaft of the turbine 6 and the bearing of the magnetic coupling 8 are preferably made of ceramic or the like that does not wear due to high speed rotation.

Further, in this embodiment, in order to effectively cool the condenser 3, the fin 9 for receiving cold air from the fan 7 is formed on the upper surface of the condenser 3. The fin 9 is preferably formed by a plurality of pin fins. With such a configuration, after the cool air from the fan 7 is vertically blown to the pin fins, the wind that takes heat from the fins 9 passes between the pin fins and is discharged in the horizontal direction. The street becomes smooth and the condenser 3 can be cooled efficiently.

Next, the LS of the present embodiment having the above configuration
The operation of the cooling device I will be described with reference to FIG.

As shown in FIG.
Working fluid 5 when SI does not generate heat above the specified temperature
Is stored as liquid in the evaporation unit 2. Since the working fluid 5 is enclosed in a state close to a vacuum, when the LSI generates heat, the working fluid 5 in the evaporation portion 2 immediately evaporates due to this heat, and the LSI is cooled by the movement of heat at this time. To be done.

Further, since the working fluid 5 evaporates, the pressure in the evaporating section 2 rises, whereby the vapor flow of the working fluid 5 moving from the high-pressure evaporating section 2 to the low-pressure condensing section 3 at high speed. Occurs. As shown by the arrow in FIG. 2, this steam flow passes through the feed pipe 41 and is ejected from the nozzle 41a to rotate the turbine 6. Then, the fan 7 is driven and cold air is blown to the fins 9.

The cool air cools the condenser 3, and the working fluid 5 in the condenser 3 is condensed and returns to liquid. Then, as shown by the arrow in FIG. 2, the working fluid 5, which has become a liquid, flows into the evaporator 2 from the return pipe 42 by gravity, and is again used for cooling the LSI.

By circulating the working fluid 5 as described above, the LSI is cooled to a specified temperature. Further, after the LSI reaches the specified temperature, the working fluid 5 in the evaporator 2 does not evaporate, so that the circulation of the working fluid 5 is stopped and the driving of the fan 7 is stopped.

Further, the evaporation amount of the working fluid 5 is determined by the above LS.
Since it is proportional to the heat generation amount of I, when the heat generation amount of the LSI is large, the evaporation amount of the working fluid 5 increases,
The moving speed of the steam flow becomes faster, and the rotation speed of the fan 7 becomes higher. On the other hand, when the heat generation amount of the LSI is small, the evaporation amount of the working fluid 5 becomes small, the moving speed of the vapor flow becomes slow, and the rotation speed of the fan 7 becomes low. in this way,
In the LSI cooling device of the present embodiment, the cooling efficiency can be automatically adjusted according to the heat generation amount of the LSI.

According to the LSI cooling apparatus of this embodiment, the fan 7 is driven and the LSI is cooled by utilizing the circulation of the vapor flow of the working fluid 5 generated by the heat generation of the LSI. The efficiency can be adjusted automatically. Therefore, no power supply is required to cool the LSI, and the LSI can be cooled effectively.

Further, since the fan 7 is driven by utilizing the circulation of the vapor flow of the working fluid 5, there is an effect that no noise is generated at all.

Further, since the evaporator 2 and the condenser 3 are vertically stacked, the side walls of the condenser 3 and the evaporator 2 can be joined to each other, and the cool air of the fan 7 indirectly connects the LSI. Can be cooled. Furthermore, by stacking the evaporator 2 and the condenser above and below,
The opening space in the lateral direction of the present cooling device can be widened.

In the above embodiment, the LSI case 1 is used.
Although the LSI is indirectly contacted with the evaporation unit 2 via the above, the heat dissipation surface of the LSI may be directly contacted with the evaporation unit 2 without via the LSI case 1.

If a motor fan for sucking the air inside the electronic equipment casing to the outside is provided and the air inside the electronic equipment is constantly refreshed, the fan 7 will not re-inhale the air blown onto the fins 9. The LSI can be cooled more effectively.

Next, the LSI according to the second embodiment of the present invention
The cooling device will be described. FIG. 3 is a side sectional view of an LSI cooling device according to the second embodiment of the present invention.

In the figure, in the LSI cooling apparatus of this embodiment, the evaporating section 2 and the condensing section 3 are laterally connected via a single pipe 4, and the evaporating section 2, the condensing section 3 and the pipe 4 are connected. A wick 10 for circulating the working fluid 5 condensed on the condenser section 3 side to the heat generating section 2 side is formed on the inner peripheral wall of the. Further, the wick 10 is formed of, for example, a wire net, a fiber, or a porous material.

According to this structure, the working fluid 5 condensed in the condenser 3 can be forced to flow into the evaporator 2 by the capillary phenomenon of the wick 10.
Therefore, gravity for returning the condensed working fluid 5 to the evaporation unit 2 is not necessary, and the degree of freedom of the installation positions of the evaporation unit 2 and the condensation unit 3 can be increased.

Further, since the evaporating section 2 and the condensing section 3 are provided in the horizontal direction, the space for opening the cooling apparatus in the vertical direction can be widened.

Next, the LSI according to the third embodiment of the present invention
4 is a perspective view showing an LSI cooling device according to the third embodiment of the present invention.

In the figure, the LSI cooling device according to the present embodiment has two evaporators 2 connected to a condenser 3 via a pipe 4.
2 is connected, and the LSI cases 1 and 1 are attached to the evaporation units 2 and 2, respectively. With such a configuration, the two condensers 3, the fins 9 and the fan 7 can cool the two LSIs to control the temperature.

It is also possible to connect two or more evaporators 2 and 2 to the condenser 3 to cool a plurality of the LSIs.

[0052]

As described above, according to the LSI cooling apparatus of the present invention, the fan can be driven and the temperature of the LSI can be adjusted according to the heat generation temperature of the LSI, although no power source or temperature sensor is required. The rotation speed of the fan can be automatically adjusted, and the LSI can be effectively cooled. In addition, there is an effect that no noise is generated during cooling of the LSI.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an LSI cooling device according to an embodiment of the present invention.

FIG. 2 is a side sectional view of the LSI cooling device.

FIG. 3 is a side sectional view showing an LSI cooling device according to a second embodiment of the present invention.

FIG. 4 is a perspective view showing an LSI cooling device according to a third embodiment of the present invention.

[Explanation of symbols]

 1 LSI Case 2 Evaporator 3 Condenser 4 Pipe 5 Working Fluid 6 Turbine 7 Fan 8 Magnetic Coupling 9 Fins 10 Wick 41 Feed Pipe 42 Return Pipe

Claims (6)

[Claims] 1. A cooling device for individually cooling an LSI mounted on a circuit board, comprising: an evaporation unit directly or indirectly attached to a heat dissipation surface of the LSI; and a connection to the evaporation unit via a pipe. The condensing part, the internal space in which the evaporating part, the condensing part and the pipe are continuous is decompressed to a substantially vacuum state, and the working fluid enclosed in the internal space, and the fan rotatably attached to the outside of the condensing part. A cooling device for an LSI, comprising: a turbine that is located in the condensing portion and that rotates the fan according to a flow of the working fluid. 2. The L according to claim 1, wherein the condenser section is provided with fins for cooling the condenser section by receiving the wind of the fan.
SI cooling system. 3. The wick that circulates the working fluid condensed on the condenser section side to the heat generating section side on the inner peripheral walls of the evaporator section, the condenser section and the pipe. LSI cooling device. 4. The cooling device for an LSI according to claim 1, wherein the evaporating section and the condensing section are provided one above the other. 5. The cooling device for an LSI according to claim 1, wherein the evaporating section and the condensing section are provided laterally. 6. The L according to claim 1, 2, 3 or 5, wherein a plurality of the evaporators are connected to the condenser through the pipes, and the LSI is attached to each of the evaporators.
SI cooling system.