JP2582144Y2 - Switching power supply circuit board - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a multi-layer substrate provided with measures against radiation noise when a main circuit and a control circuit of a switching power supply are mounted on the same substrate.

[0002]

2. Description of the Related Art In order to reduce the size of a switching power supply, a main circuit and a control circuit are formed on a single substrate. In this case, it is necessary to take measures against radiation noise. For example, a DC-D in which a board-type switching power supply package or a communication load package is arranged adjacently in a tray
In the C converter and the like, various measures are taken to prevent mutual interference of radiation noise. One example is a multi-layer circuit in which a circuit pattern is placed on a board, another board is attached to the pattern surface of the mounting board on which components are mounted (the component non-mounting surface), and a shield pattern is placed on the entire back surface of the board. Substrates are often used.

[0003]

In this case, however, in this case, noise interference between adjacent substrates can be prevented by the shield pattern, but it is generated by the switching operation of the main circuit in the same substrate. Noise currents induced by noise power also flow through the shield pattern on the main circuit side to the shield pattern on the control circuit side, thereby causing the disadvantage that the control circuit is interfered with noise and the operation becomes unstable. I have.

The present invention has been made in view of the above-described circumstances, and a high-density mounting board for the purpose of miniaturization includes a main circuit serving as a source of switching noise and a control circuit susceptible to noise. Is mounted on a single board at a high density, a shield pattern is arranged so that radiated noise emitted from the main circuit pattern surface of the switching power supply does not interfere not only in the adjacent board but also in its own board. Using a multilayer board, the main circuit and control circuit can be electrically separated and shielded without changing the mounting volume and density of the switching power supply, preventing mutual interference due to radiated noise, and stabilizing the switching power supply. It is an object of the present invention to provide a switching power supply circuit board capable of realizing an operation.

[0005]

Corresponding to the SUMMARY OF THE INVENTION This object, a switching power supply circuit board of this invention is the secondary side of the tiger <br/> Nsu via the supplied main switching element and the main transformer a DC input A switching power supply circuit board in which a main switching circuit including the main switching element and a control signal circuit thereof in a switching power supply for supplying an output to a single multilayer substrate are provided, and a circuit pattern is formed on one layer of the multilayer substrate. Arranging, separately mounting and arranging the main switching circuit component and the control signal circuit component, arranging a plurality of shield patterns on another layer of the multi-layer board, and arranging the plurality of shield patterns relative to each other at the position of the main switching circuit component opposing first shield pattern and the control signal circuit a second shield pattern and configuration <br/> only the Rutotomoni opposite the position of the component in The second shield pattern first shield
It is characterized in that the pattern is provided separately and independently from the islands via an insulating band , and the shield pattern corresponding to the main switching circuit has the same potential as one potential of the output voltage.

[0006]

It is a common practice to cover a noise source of a circuit with a metal shield plate. By providing a shield pattern on one side of the multilayer board,
The purpose of shielding radiation noise to the outside is achieved. However, an eddy current due to radiation noise flows in the shield pattern, and this interferes with other circuit parts on the same substrate, for example, a control circuit. Therefore, the multilayer board of the present invention makes the shield pattern of the circuit part susceptible to radiation noise electrically insulated and independent from other shield pattern parts, and no eddy current circuit is formed in the shield pattern of the circuit part susceptible to noise. In this way, it is a structure for preventing noise interference.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the drawings showing one embodiment. FIG. 1 is a cross-sectional view of the multi-layer substrate of the present invention, FIG.
FIG. 4 is a conceptual diagram showing the distribution of eddy current due to radiation noise flowing in the shield pattern of the conventional multilayer substrate and the shield pattern of the multilayer substrate of the present invention.

As shown in FIG. 1, a multilayer substrate 20 according to the present invention has a first circuit pattern 4 and a second circuit pattern 11 disposed on one or both sides of a glass epoxy layer 3, for example. Is formed, and a first shield pattern 8 and a second shield pattern 9 are arranged on one surface of another glass epoxy layer 7 to form a second layer 2. The first layer 1 and the second layer 2 are formed by shielding patterns 8 and 9 of the first layer 1.
To form a multilayer substrate so as not to electrically overlap the circuit patterns 4 and 11 described above.

[0009]

The main switching circuit component 5 and the control signal circuit component 6 correspond to the first circuit pattern 4 and the second circuit pattern 11 on one surface of the first layer 1, that is, the component mounting surface B. And then separate them into groups and mount them separately.

On the other hand, the shield pattern disposed on the back surface of the second layer includes the first shield pattern 8 and the control signal circuit component 6 on the surface opposite to the portion where the main switching circuit components 5 are grouped and mounted. The second shield pattern on the surface opposed to the portion where is grouped and mounted is separated and patterned independently by the insulating band 10.

The multilayer board 20 thus configured is used by being incorporated in a package A of a switching power supply shown in FIG.

That is, the switching power supply package A
Are arranged with the component mounting surface B of the multilayer substrate 20 inside and the shield pattern surface outside.

On the other hand, the component mounting surface B is covered with an aluminum shield plate E or the like to form a package.

With this configuration, the switching power supply circuit is covered with the shielding plate, and does not emit radiation noise to the outside.

The shield pattern surface D is formed such that the second shield pattern 9 is isolated from the first shield pattern 8 by an insulating band 10. This insulating band 10
Is a portion where the shielding material is not present and the glass epoxy layer is exposed.

Next, the operation of the switching power supply circuit board configured as described above will be described with reference to a conceptual diagram showing the distribution of eddy current due to radiation noise flowing on the shield pattern surface in FIG. FIG. 3 shows a conventional shield pattern in which a control circuit portion is patterned on one surface in a main circuit portion.

In this case, radiation noise due to switching generated in the main circuit portion flows as an eddy current as shown by an arrow in the figure on the shield pattern surface, and also flows to the control circuit portion.
The eddy current flowing in the control circuit unit causes noise interference in the control circuit unit, which causes unstable operation of the control circuit.

In the circuit board of the present invention, as shown in FIG. 4, since the shield pattern of the control circuit portion is insulated from the shield pattern of the main circuit portion without islands, eddy current due to noise in the main circuit portion is provided. Does not flow to the control circuit as indicated by the arrow in the figure. Therefore, the control circuit does not receive noise interference.

The shield pattern of the main circuit section (first shield pattern 8 in FIG. 1) is clamped to either the plus or minus potential of the output circuit of the switching power supply in order to keep the potential stable. If this is done, the noise interference effect can be made more advantageous.

[0020]

[Effect of the invention] As described above, the multilayer substrate according to the invention is:
By separating the shield pattern on the outer surface of the board from the main circuit part to the control circuit part, radiation noise to the electronic circuit of the adjacent board is suppressed and noise interference to other circuits such as the control circuit on the same board is suppressed. Unstable operation can also be prevented. In addition, since no additional structure is required to prevent noise, it becomes extremely advantageous as a package structure for a high-density mounting power supply.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a multilayer substrate of the present invention.

FIG. 2 is a conceptual diagram of a package configuration of a switching power supply exhibiting a noise interference effect according to the present invention.

FIG. 3 is a conceptual diagram showing an eddy current distribution due to radiation noise flowing through a shield pattern of a conventional multilayer substrate.

FIG. 4 is a conceptual diagram showing an eddy current distribution due to radiation noise flowing in the shield pattern of the multilayer substrate of the present invention.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 first layer 2 second layer 3 glass epoxy layer 4 first circuit pattern 5 main switching circuit component 6 control signal circuit component 7 glass epoxy layer 8 first shield pattern 9 second shield pattern 10 Insulation band 11 Second circuit pattern 20 Multilayer substrate A Switching power supply package B Component mounting surface C Circuit pattern layer D Shield pattern surface E Aluminum shield plate

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kenji Matsumoto 1-6-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (72) Masatoshi Honda 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (72) Katsuo Maki inventor 1-6-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (56) References JP-A-4-211200 (JP, A) (58) Survey Field (Int.Cl. ⁶ , DB name) H05K 9/00 H02M 3/28

Claims (1)

(57) [Scope of request for utility model registration] 1. A single main switching circuit and a control signal circuit including the main switching element in the switching power supply for supplying an output to supply a DC input via the main switching element and the main transformer on the secondary side of the transformer A switching power supply circuit board arranged on a multilayer board of
A circuit pattern is arranged on one layer of the multilayer substrate, a main switching circuit component and a control signal circuit component are separately mounted and arranged, a plurality of shield patterns are arranged on another layer of the multilayer substrate, and the plurality of The shield pattern has a first shield pattern facing the position of the main switching circuit component and a second shield pattern facing the position of the control signal circuit component.
Rutotomoni provided a shield pattern, the second shield
The pattern is connected to the first shield pattern via an insulating band.
And a shield pattern corresponding to the main switching circuit and having the same potential as one of the output voltages.