JPH0638250U - IC fixing structure - Google Patents

Abstract

(57) [Summary] [Object] In an IC fixing structure in which an IC 10 connected to a printed circuit board 14 is fixed to a heat sink 30 via a holder 40, the IC 10 and the heat sink 30 are fixed in close contact with each other without a gap. It is possible to provide a fixing structure of an IC that can sufficiently radiate the amount of heat generated in the IC 10 to the heat dissipation plate 30 side. In the fixing structure of the IC 10 in which the IC 10 is connected and fixed to the printed circuit board 14 and the heat radiating plate 30 is fixed to the IC 10 via a holder 40, a close contact portion 41 with the heat radiating plate 30 and a heat radiating plate are sequentially attached to the holder 40 from above. 30 and the screw fixing portion 42 having a gap between the IC 10 and the heat radiating plate 30.
An IC fixing structure in which a pressing portion 47 for pressing to the side is formed.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an IC fixing structure, and more particularly, to an IC fixing structure for fixing a power IC, for example, in an audio device to a heat sink.

[0002]

[Prior art]

 FIG. 3 is a perspective view showing a conventional structure for fixing an IC to a holder, and 11 in the drawing shows an IC package formed by ceramics or the like. A heat sink 12 made of a metal plate having a larger dimension (length L is about 30 mm and height H is about 20 mm) is fixed to the side surface of the IC package 11, and a plurality of terminals 13 are provided on the bottom surface of the IC package 11. Is formed so as to form an IC 10 of about 25 W × 4 output, which is generally called a power IC. Reference numeral 20 in the drawing denotes a holder formed of a thin sheet metal, and a screw hole 22a is opened at the center through an inverted L-shaped connecting portion 23 in the upper part near both ends of the rectangular supporting portion 27. Screwed portions 22 are formed, and inverted J-shaped claw portions 24 are formed near the inside of the screwed portions 22 above the support portion 27. Further, opposite end portions of the support portion 27 are each formed into an inverted L shape. The holder 20 is configured by forming the leg portions 25 having a shape. Then, the upper surface of the heat radiating portion 12 is sandwiched between the claw portion 24 and the supporting portion 27, and the IC 10 is supported by the holder 20, so that the circuit and the terminal 13 on the printed circuit board 14 are soldered by a solder bath (not shown). Even when this is done, the upright state of the IC 10 with respect to the printed circuit board 14 is maintained.

By the way, since the IC 10 has a large output and the heat radiation capacity from the heat radiation portion 12 alone is insufficient, another heat radiation plate such as a larger heat sink is arranged and the IC 20 is closely attached to the heat radiation plate using the holder 20. It is installed in a state where the heat dissipation capacity is increased. The attachment of the heat sink is performed on the upper side of the IC 10 because the attachment space is usually not provided on the length L direction side of the IC 10.

FIG. 4 is a cross-sectional view showing a conventional fixing structure of an IC to a heat dissipation plate, and shows a cross section taken along line YY ′ in FIG. Reference numeral 30 in the drawing denotes a heat sink generally called a heat sink, which is formed into an approximately rectangular parallelepiped shape by using an aluminum plate having excellent thermal conductivity, aluminum die cast, etc., and the heat receiving surface 30a with which the IC 10 contacts is formed smoothly. A recess 31 is formed at a predetermined position on the heat receiving surface 30a side, and a screw hole 32 is formed at a predetermined position above the recess 31. Then, the claw portion 24 is housed in the concave portion 31, the IC heat radiating surface 12a is brought into contact with the heat receiving surface 30a, and the bolt 26 inserted into the screw holes 32 and 22a is screwed, whereby the IC 10 is fixed to the heat radiating plate 30. It is installed.

[0005]

[Problems to be solved by the device]

 In the IC fixing structure described above, the IC 10 is supported by the vicinity of the upper end of the heat radiating portion 12 being sandwiched between the claw portion 24 and the supporting portion 27, and stress is applied to the IC 10 in the direction indicated by the arrow A in the figure. If it hangs, the lower part of the IC 10 may easily rotate in the direction of arrow A with the upper part of the IC 10 as a rotation axis. Further, there is a problem in that the point of action of the pressing force on the heat radiating portion 12 in the screwing portion 22 is in the vicinity of the upper end of the heat radiating portion 12 and does not reach the lower portion of the IC 10. Therefore, it is difficult for the IC heat radiation surface 12a and the heat radiation surface 30a to be in close contact with each other, and a gap is formed between the lower portion of the IC 10 and the heat radiation plate 30, so that the heat generation amount of the IC 10 is not sufficiently radiated through the heat radiation plate 30. As a result, there is a problem that the performance of the device is adversely affected, or the cost is increased due to the use of a larger heat dissipation plate, or the size of the entire device is increased.

The present invention has been made in view of the above problems, and in an IC fixing structure in which an IC connected and fixed to a printed circuit board is fixed to a heat dissipation plate via a holder, the IC and the heat dissipation plate are connected to each other. It is an object of the present invention to provide an IC fixing structure that can be fixed in close contact without a gap and can sufficiently radiate the amount of heat generated in the IC.

[0007]

[Means for Solving the Problems]

 In order to achieve the above object, an IC fixing structure according to the present invention is an IC fixing structure in which an IC is connected and fixed to a printed circuit board, and a heat sink is fixed to the IC via a holder. It is characterized in that a contact portion with the heat dissipation plate, a screwing portion having a gap between the heat dissipation plate, and a pressing portion for pressing the IC toward the heat dissipation plate are formed in this order.

[0008]

[Action]

 It is generally known that when there is a gap between objects, a heat insulating layer is formed and the thermal conductivity is significantly reduced. Therefore, by bringing the contact surface of the IC and the heat sink into close contact, the IC It is considered that the heat conduction from the heat sink to the heat sink can be increased.

According to the IC fixing structure of the present invention, in the IC fixing structure in which the IC is connected and fixed to the printed circuit board and the heat sink is fixed to the IC via the holder, the IC is fixed to the holder in order from above. A close contact portion with the heat dissipation plate, a screwing portion having a gap between the heat dissipation plate and a pressing portion for pressing the IC toward the heat dissipation plate are formed, and the close contact portion serves as a fulcrum, and the screw The stop portion serves as a force point, and the pressing portion serves as an action point. Therefore, the force point and the action point are located on the same side with respect to the fulcrum, and when a force is applied to the screwing portion, the force is surely applied to the pressing portion in the same direction. Therefore, the pressing force that presses the IC toward the heat dissipation plate is transmitted to the lower part of the IC, and the contact surfaces of the IC and the heat dissipation plate come into close contact with each other, and the amount of heat generated in the IC causes the heat dissipation plate. Will be sufficiently transmitted to the heat dissipation.

[0010]

【Example】

 Hereinafter, an embodiment of an IC fixing structure according to the present invention will be described with reference to the drawings. It should be noted that components having the same functions as those of the conventional example are designated by the same reference numerals. FIG. 2 is a perspective view showing a structure for fixing the IC to the holder according to the embodiment, and 40 in the figure indicates the holder. The holder 40 is formed of a thin sheet metal, and a connecting portion 43 having a rectangular shape in a plan view is horizontally extended from an upper portion of the pressing portion 47 having a rectangular shape in a front view, and a front end of the connecting portion 43 is formed. A rectangular screw stop portion 42 having two screw holes 22a opened at a predetermined position and a close contact portion 41 are vertically extended and connected to each other, and the front end portion of the connecting portion 43 is substantially formed. A claw portion 24 extending downward from the center is provided. Reinforcing ribs 44 are extendedly formed from both side ends of the close contact portion 41, the screw fastening portion 42, the connecting portion 43 and the pressing portion 47, and the lower portion of the rib 44 is a leg portion 45. Then, the IC heat radiation surface of the heat radiation portion 12 and the surface 11a of the IC package 11 opposite to the heat radiation portion 12 are sandwiched between the claw portion 24 and the pressing portion 47, so that the IC 10 is held by the holder 40. When the circuit on the printed circuit board 14 and the terminal 13 are soldered with a solder bath (not shown) as in the case of the conventional example described above, the upright state of the IC 10 with respect to the printed circuit board 14 is maintained. It is supposed to be maintained.

FIG. 1 is a sectional view showing a fixing structure of an IC according to the present embodiment to a heat sink, and shows a section taken along line YY ′ in FIG. Reference numeral 30 in the figure denotes a heat sink similar to that of the above-mentioned conventional example. The heat receiving surface 30a with which the IC 10 contacts is formed smooth, and a recess 31 is formed at a predetermined position on the heat receiving surface 30a side. A screw hole 32 is formed at a predetermined position above.

When the IC 10 is fixed to the heat dissipation plate 30 using the IC fixing structure configured as described above, first, the convex portion of the claw 24 is inserted into the concave portion 31 and the close contact portion 41 is tightly attached to the contact surface 30b. Then, the bolt 26 inserted into the screw holes 32 and 22a is screwed. Then, as shown by an arrow C in the figure, the lower end B of the close contact portion 41 serves as a fulcrum, the screw hole 22a of the screwing portion 42 serves as a force point, and the pressing force indicated by the arrow D acts on the surface 11a of the IC package 11. The IC heat radiation surface 12a comes into close contact with the heat receiving surface 30a.

As a result, the IC 10 and the printed circuit board 14 can be fixed to the heat sink 30 via the holder 40, the IC 10 and the heat sink 30 can be brought into close contact with each other, and the amount of heat generated by the IC 10 can be reduced. The heat can be sufficiently dissipated to the side. Therefore, it is possible to suppress the adverse effect on the device due to the temperature rise, or to suppress the cost increase and the increase in the size of the entire device due to the use of a larger heat sink.

[0014]

[Effect of device]

 As described above in detail, in the IC fixing structure according to the present invention, in the IC fixing structure in which the IC is connected and fixed to the printed circuit board and the heat sink is fixed to the IC via the holder, the holder is In order from above, a close contact portion with the heat dissipation plate, a screwing portion having a gap between the heat dissipation plate and a pressing portion for pressing the IC toward the heat dissipation plate are formed. The heat sink and the heat sink can be brought into close contact with each other, and a sufficient amount of heat generated in the IC can be radiated to the heat sink side. Therefore, it is possible to suppress the adverse effect on the device due to the temperature rise, or to suppress the cost increase and the increase in the size of the entire device due to the use of the larger heat sink.

[Brief description of drawings]

FIG. 1 is a sectional view showing a structure for fixing an IC to a heat sink according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a structure for fixing an IC to a holder according to an embodiment.

FIG. 3 is a perspective view showing a conventional structure for fixing an IC to a holder.

FIG. 4 is a cross-sectional view showing a conventional fixing structure of an IC to a heat sink.

[Explanation of symbols]

 10 IC 14 Printed Circuit Board 30 Heat Dissipating Plate 31 Recess 40 Holder 41 Close Contact 42 Screw Stop 47 Pressing Part

Claims (1)

[Scope of utility model registration request] 1. An IC fixing structure in which an IC is connected and fixed to a printed circuit board, and a heat radiating plate is fixed to the IC via a holder, in the holder, a contact portion with the heat radiating plate in order from above, the heat radiating plate. A fixing structure for an IC, comprising: a screwing part having a gap between the pressing part and a pressing part for pressing the IC toward the heat dissipation plate.