JPH1141916A - Switching power supply - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a switching power supply easy to design and assemble by making a shield structure simple. SOLUTION: A switching power supply includes an angularly bent tube-shaped metallic shield case 6, an insulating resin mold case 7 inserted inside the metallic shield case 6, a printed circuit board 1 supported by the mold case 7, and a switching power circuit part 2 on the printed circuit board 1. The shield case 6 has a cut bent part 61 which is projected from the shield case 6 and soldered directly with a grounding pattern of the printed circuit board 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switching power supply requiring a shield structure.

[0002]

2. Description of the Related Art A switching power supply device known as a switching regulator generates high-frequency jamming waves accompanying a switching operation, and adversely affects peripheral electric devices. For this reason, the switching power supply generally covers the entire circuit component with a metal shield case.

FIG. 6 is an assembled perspective view showing an example of a conventional switching power supply device. In this figure, 1 is a printed circuit board, 2 is a switching power supply circuit component mounted on the surface of the printed circuit board 1, 3 is a metal shield case that covers the upper space of the printed circuit board 2 and has an open lower surface, and 4 is a printed circuit board. A metal shield cover 5 that covers the back side of the board 1 is an insulating sheet that prevents the soldered portion exposed on the back side of the printed board 2 from coming into contact with the shield cover 4. Note that the upper end surface 31 of the shield case 3 may be formed of a shield cover that can be opened.

[0004] The shield structure of the above power supply device mechanically takes the form of covering the periphery of the printed circuit board 2 with the shield case 3 and the shield cover 4, and electrically cuts and raises a part of the shield case 3. The bent portion 32 is soldered to a ground pattern (not shown) formed on the back surface of the printed circuit board 2 as shown in FIG. The insulating sheet 5 has a cutout 51 so that only the ground pattern of the printed board 2 can contact the bent portion 32 of the shield case 3.

[0005]

The above-mentioned shield structure of the power supply device has the following problems. 1) Insulation sheet 5
In order to perform insulation by the two surfaces 52 and 53, the sheet 5
Requires bending. 2) A hook, a double-sided tape, or the like is required to fix the insulating sheet 5. When the sheet 5 is fixed with screws, the number of screwed locations increases.
3) A structure for fixing the printed circuit board 1 is required on the shield case 3 side, and the case structure is complicated. 4) Since the ground connection between the substrate 1 and the case 3 and the fixing of the substrate 1 to the case 3 are performed by the same soldering, the degree of freedom in device design is low. These points are problems to be solved by the present invention.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a switching power supply device having a simplified shield structure and easy to design and assemble.

[0007]

SUMMARY OF THE INVENTION The object of the present invention is to provide a metal cylindrical shield case bent into a prismatic shape,
This can be achieved by a switching power supply device including an insulating resin molded case mounted in the shield case, a printed circuit board supported by the molded case, and a switching power supply circuit component mounted on the printed circuit board.

Another object of the present invention is to provide a metal shield case bent in a U-shaped cross section, an insulative resin mold case mounted in the shield case, and supported by the mold case. Printed circuit board,
This can be achieved by a switching power supply device including a switching power supply circuit component mounted on the printed circuit board and a metal shield cover for closing an opening of the shield case.

[0009] It is preferable that the printed circuit board has a bent portion cut and raised from the shield case and directly soldered to a ground pattern of the printed circuit board.

[0010] Preferably, the printed circuit board has a bent portion cut and raised from the shield case and directly screwed to an earth pattern of the printed circuit board.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments shown in the drawings. FIG. 1 is an assembled perspective view showing an embodiment of the present invention, and FIGS. 2 and 3 are different partial sectional views after the assembly. In the figure, reference numeral 6 denotes a metal cylindrical shield case bent into a prism shape, 7 denotes an insulating resin mold case mounted in the shield case 6, 1 denotes a printed board supported by the mold case 6, and 2 denotes A switching power supply circuit component mounted on the printed circuit board 1;
Reference numeral 61 denotes a bent portion cut out from the shield case 6 and directly soldered to a ground pattern (not shown) of the printed circuit board 1.

The mold case 7 is a resin integral molding having a U-shaped cross section that opens only the upper side (the mounting position of the component 2) of the printed circuit board 1 and insulates the remaining three surfaces (lower surface, left and right side surfaces). Goods. The mold case 7 has elasticity, and a groove 71 into which a side portion of the printed circuit board 1 is fitted.
Are formed so as to firmly sandwich both sides of the printed circuit board 1.

The shield case 6 and the mold case 7 are each provided with an engaging portion (not shown) so that the mold case 7 can be positioned at a predetermined position on the shield case 6 and temporarily fixed. Has become.

A bent portion 61 of the shield case 6 is formed by being cut and raised from below as shown in FIG. 2 or from above as shown in FIG. 3, and is connected to a ground pattern on the back surface of the printed circuit board 1 by solder 8. . The connection by the solder 8 has a function of electrically connecting the shield case 6 to the ground pattern of the printed circuit board 1 to provide a shielding effect, and
A function of mechanically fixing the printed circuit board 1 to the shield case 6.

The printed board 1 and the mold case 7 are
Since the printed board 1 is integrated by fitting the printed board 1 into the groove 71 of the mold case 7, the above connection by the solder 8 fixes both the mold case 7 and the printed board 1 to the shield case 6 at the same time. Will be.

The structure of the switching power supply of the present invention has the following advantages. 1) The mold case 7 is easier to secure the insulation and the extended surface distance than the conventional insulating sheet 5. 2) When the mold case 7 is used, the printed circuit board 1 can be easily positioned and fixed. 3) Since the mold case 7 is an integrally molded product made of a resin material, it is stronger than the conventional insulating sheet 5. 3) Mold case 7
And the printed circuit board 1 are integrated in advance, so that it is easy to assemble the shield case 6. 4) Since the restriction on the grounding position is relaxed, the grounding is facilitated. 5) Since the number of parts constituting the shield case 6 is small, the shield effect is improved. 6) Since only the printed circuit board 1 and the shield case 6 need to be grounded, the degree of freedom of the grounding structure is increased.

FIG. 4 is a sectional view showing another embodiment of the present invention. In this figure, 6A is a metal shield case bent in a U-shape in cross section, 7 is an insulating resin mold case mounted in the shield case 6A, 1 is a printed circuit board supported by the mold case, 6B Is a metal shield cover for closing the opening of the shield case 6A, 62A and 62B are cut and raised from the shield case 6A, and screws 9A
This is a bent portion directly screwed at 9B. The switching power supply circuit component (2) mounted on the printed circuit board 1 is omitted in the drawing.

In this embodiment, the shield case 6A is 3
The surface is shielded, and the remaining surface is shielded by the shield cover 6B. In the case of this example, the overall strength is ensured by a combination of the shield case 6A forming three surfaces and the mold case 7 forming three surfaces rotated by 90 degrees so as to cover the open surface of the shield case 6A. Shield cover 6
B is for electromagnetically shielding the open surface of the shield case 6A and does not contribute to mechanical strength.

One of the features of the embodiment shown in FIG. 4 is a screwing structure for connecting the shield case 6A to the ground pattern of the printed circuit board 1. That is, the bent portions 62A and 62B are cut and raised from the shield case 6A, and the bent portions 62A and 62B are directly screwed to the ground pattern of the printed circuit board 1 with the screws 9A and 9B.

Conventionally, the screwing of this ground connection is performed as shown in FIG.
I'm going like That is, there is no cut-and-raised portion from the shield case 6A, and both ends of the independent metal ground plate 10 are screwed to the printed circuit board 1 and the shield case 6A with screws 9A and 9C, respectively, thereby grounding the shield case 6A. I am taking it.

The grounding method using an independent grounding plate 10 as shown in FIG. 5 not only increases the number of parts but also increases the number of parts.
There is a problem that the number of steps and places for screwing are doubled. FIG.
According to the embodiment of the present invention, an independent ground plate is not required, and the number and steps of screwing are reduced by half.

[0022]

As described above, according to the present invention, it is possible to provide a switching power supply device whose shield structure is simplified and whose design and assembly are easy.

[Brief description of the drawings]

FIG. 1 is an assembled perspective view showing one embodiment of the present invention.

FIG. 2 is a partial sectional view of the apparatus of FIG.

FIG. 3 is a different partial cross-sectional view of the apparatus of FIG. 1;

FIG. 4 is a cross-sectional view of another embodiment of the present invention.

FIG. 5 is a sectional view showing an example of a conventional switching power supply device.

FIG. 6 is an assembled perspective view showing another example of the conventional switching power supply device.

FIG. 7 is a partial sectional view of the apparatus of FIG. 6;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Printed circuit board 2 Switching power supply circuit component 6 Shield case 7 Mold case 8 Solder 9 Screw 61 Bent part 62 Bent part

Claims (4)

[Claims] 1. A metal cylindrical shield case bent into a prismatic shape, an insulating resin mold case mounted in the shield case, a printed board supported by the mold case, and the printed board And a switching power supply circuit component mounted thereon. 2. A metal shield case bent in a U-shaped cross section, an insulating resin mold case mounted in the shield case, a printed circuit board supported by the mold case, A switching power supply device comprising: a switching power supply circuit component mounted on a substrate; and a metal shield cover for closing an opening of the shield case. 3. It is cut and raised from the shield case,
3. The switching power supply device according to claim 1, further comprising a bent portion directly soldered to an earth pattern of the printed circuit board. 4. It is cut and raised from the shield case,
3. The switching power supply according to claim 1, further comprising a bent portion directly screwed to an earth pattern of the printed circuit board.