JP2540467B2 - LC filter - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an LC filter capable of surface connection to a circuit board.

[Prior art]

In recent years, individual circuit elements including coils have become very small, and their height is 5 mm or less, and the size is as small as the length and width. These circuit elements are directly surface-connected to the conductor pattern of the circuit board by using an automatic machine. And, it is required that the LC filter in which the circuit elements are combined can be surface-connected to the conductor pattern of the circuit board in the same manner as the individual circuit elements.

FIG. 10 is a perspective view of a conventional LC filter capable of surface connection.

A coil 2 wound around a core is arranged on the main surface of a synthetic resin base 1, and terminals 4 made of U-shaped metal pieces are fitted on the side surface 3 so that the main surface of the base 1 is sandwiched from above and below. It is fixed at. The chip-shaped capacitor 5 is surface-connected to the conductor pattern 6 provided on the same main surface as the coil 2, and the conductor pattern 6 is connected to the terminal 4. Coil 2
The lead 7 is connected to the flat terminal 4 by soldering or spot welding. Then, the terminal 4 is surface-connected to another circuit board.

In such a conventional LC filter, since the coil 2 and the capacitor 5 are connected via the conductor pattern 6, it is necessary to print the conductor pattern 6 on the base 1. However, the conductor pattern 6 having a width of 0.5 mm and a film thickness of several tens of μm
Is easily damaged when the capacitor 5 and the terminal 4 are connected.
In particular, since the connection between the terminal 4 and the conductor pattern 6 is a connection between the metal piece and the thin conductor film, the conductor pattern 6 is likely to be damaged and the reliability is poor.

Further, the terminal 4 is a portion to which the leads 7 of the coil 2 are connected at the same time as the portion to be surface-connected. Therefore, the lead 7 is apt to cause a disconnection accident due to the contact of the molten solder during the surface connection or the application of heat. Especially when the lead 7 is not entangled in the terminal 4, accidents frequently occur.

〔Task〕

A first object of the present invention is to directly connect a coil and a capacitor without using a conductor pattern and prevent a decrease in connection reliability due to the conductor pattern.

The second problem is the connection of the lead of the coil of the terminal,
The purpose is to prevent lead disconnection accidents by separating the parts that are surface-connected to the circuit board.

[Means for solving the problem]

That is, in the LC filter of the present invention, the coil wound around the core is arranged on the main surface of the base, and the first connection portion for surface connection to the circuit board, the second connection portion for connection of the lead of the coil,
A plurality of terminals each having a third connecting portion to which the chip-shaped capacitor is connected are embedded in the base in a state where each connecting portion is exposed, and the coil and the capacitor are directly connected to the terminal, and the terminal is a circuit. It is characterized in that it is surface-connected to the substrate.

Furthermore, a plurality of terminals having the first connecting portion that also serves as the third connecting portion may be embedded.

〔Example〕

An embodiment of the LC filter of the present invention will be described below with reference to FIGS. 1 to 4. 1 is a perspective view, FIG. 2 is an exploded perspective view without a capacitor, FIG. 3 is a plan view of a base, and FIG. 4 is a circuit diagram.

1 to 4, 10 is a coil wound around a drum-shaped core, 11 and 12 are chip-shaped capacitors,
13 to 16 are terminals made of L-shaped metal pieces.

The coil 10 is arranged on the main surface 18 on the front side of the base 17 made of synthetic resin, and a plurality of terminals 13 to 16 are embedded in the base 17 in a state in which three respective connecting portions are exposed. The three connection parts are a first connection part for surface connection to the circuit board, a second connection part for connection with the lead of the coil, and a chip-shaped capacitor.
It is a third connecting portion that connects 11 and 12. 1 to 3, the first connecting portion of the terminal 13 is 13A, the second connecting portion is 13B, the third connecting portion is 13C, and so on. For each terminal number, the first connecting portion is A and the second connecting portion is Is denoted by B, and the third connecting portion is denoted by C.

The main surface 18 near the coil 10 is formed with a concave portion 19 having a size capable of accommodating the capacitors 11 and 12, and the third connecting portion of the terminals 13 to 16 is exposed at the bottom of the concave portion 19. The first connecting portion and the second connecting portion of the terminals 13 to 16 are formed by exposing both ends of each terminal to the side surface of the base 17.

In FIG. 3, the coil 10 and the capacitors 11 and 12 connected to the terminals 13 to 16 are shown by circuit symbols on the base 17. Leads 20 at both ends of the coil 10 are connected to the terminals 13 and 14 in a twisted manner, the capacitor 11 is connected between the terminals 13 and 15 in the recess 19, and the capacitor 12 is connected to the terminal 14 in another recess 19. And terminal
Connect between 16 The terminal 13 functions as an input terminal, the terminal 14 functions as an output terminal, and the terminals 15 and 16 function as ground terminals, thus forming a low-pass filter as shown in FIG.

In the LC filter of the present invention, the coil 10 and the capacitors 11 and 12 can be connected via the terminals 13 and 14 without using a conductor pattern as described above. Therefore, the disconnection accident between the terminal and the conductor pattern and between the capacitor and the conductor pattern due to the conductor pattern can be completely eliminated, and the reliability of the connection can be improved. In addition, the terminal is provided with the first connecting portion and the second connecting portion separately, and the molten lead when the surface connection of the first connecting portion to the circuit board is brought into contact with the coil lead or heat is applied. There are few things. Moreover, since the lead can be connected to the second connecting portion by being entangled with each other, it is possible to almost eliminate the disconnection accident when the surface connection is made to the circuit board.

5 and 6 are views showing another embodiment of the LC filter of the present invention, FIG. 5 is a plan view of the base, and FIG. 6 is a circuit diagram.

FIG. 5 shows a coil arranged on the main surface 31 of the base 30.
32, the coil 33, the capacitor 34, and the capacitor 35 are shown by circuit symbols, respectively, and the connection between these circuit elements and the terminals 36 to 40 is shown.

The terminals 36 to 40 having an L-shaped planar shape are connected to the first connection portion for surface connection to the circuit board except the terminal 36, the second connection portion for connecting the lead of the coil, and the chip-shaped capacitors 34, 35. It has a third connecting portion, and is embedded in the base 30 in a state where each connecting portion is exposed. Further, the main surface 31 is provided with a recess 41 for accommodating the capacitors 34 and 35.
At the bottom of the recess 41, the third connecting portions of the terminals 37 to 40 are exposed. The terminal 36 passing under the recess 41 does not have the third connecting portion and is the first
It has only a connecting portion and a second connecting portion. The first connecting portion and the second connecting portion of the terminals 36 to 40 are formed by exposing both ends of each terminal from the base 30. In the terminals 36 to 40, the first connecting portion is indicated by A, the second connecting portion is indicated by B, and the third connecting portion is indicated by C, respectively.

The coil 32 is between the terminals 36 and 38, the coil 33 is between the terminals 38 and 37, the capacitor 34 is between the terminals 38 and 39 in the recess 41, and the capacitor 35 is in the other recess 41, the terminals 37 and 40.
Connect between each. The terminal 36 serves as an input terminal, the terminal 37 serves as an output terminal, the terminal 38 serves as a relay terminal, and the terminals 39 and 40 serve as ground terminals, thus forming a low-pass filter as shown in FIG.

In this way, the terminal embedded in the base 30 is the first connection portion,
Those having the second connecting portion and the third connecting portion and those having some of the connecting portions may be mixed. Further, the first connecting portion 38A of the terminal 38 which functions as a relay terminal may not be present.

7 and 8 are views showing another embodiment of the LC filter of the present invention, FIG. 7 is a plan view of the base, and FIG. 8 is a circuit diagram.

FIG. 7 shows a coil arranged on the main surface 51 of the base 50.
52, coil 53, coil 54, capacitor 55, capacitor 56
Are indicated by circuit symbols, respectively, and their circuit elements and terminals
Connections with 57-61 are shown.

The terminals 58 to 61 each having an L-shaped planar shape include a first connecting portion that is surface-connected to the circuit board, a second connecting portion that is connected to a lead of the coil,
It has a third connecting portion for connecting the chip-shaped capacitors 55 and 56, and is embedded in the base 50 in a state where each connecting portion is exposed. Further, the main surface 51 is provided with a recess 62 for accommodating the capacitors 55 and 56. On the bottom of the recess 62, the terminal 57
The third connecting portions of the terminals 58 to 61 are exposed except for. Terminal
The 57 has only the second connecting portion 57B exposed to the side surface of the base 50 without the first connecting portion and the third connecting portion. The first connecting portion and the second connecting portion of the terminals 58 to 61 except the terminal 57 are formed by exposing both ends of each terminal to the side surface of the base 50. Terminal
In 57 to 61, the first connecting portion is indicated by A, the second connecting portion is indicated by B, and the third connecting portion is indicated by C, respectively.

The coil 52 is connected between the terminals 59 and 57, the coil 53 is connected between the terminals 57 and 58, and the coil 54 is connected between the terminals 58 and 61. Further, the capacitor 55 has terminals 60 and 59 in the recess 62.
Meanwhile, the capacitor 56 is connected between the terminal 58 and the terminal 61 in another recess 62, respectively. Terminal 60 is an input terminal, terminal 58 is an output terminal,
The terminals 59 and 57 function as relay terminals, and the terminal 61 functions as a ground terminal, and a bandpass filter as shown in FIG. 8 is configured. The coil 53 serves to weaken the coupling between the coil 52 and the coil 54.

FIG. 9 is a perspective view showing still another embodiment of the LC filter of the present invention.

The coil 70 wound around the drum-shaped core is arranged on the main surface 72 on the front side of the base 71.

In the base 71, four terminals 73 having a first connecting portion that is surface-connected to the circuit board and a second connecting portion that is connected to the lead of the coil are embedded with the respective connecting portions exposed. The plan view of the base 71 is almost the same as the case where the recess 19 and the third connecting portion of each terminal are removed from FIG. The terminal 73 having an L-shaped planar shape has its both ends exposed to the side surface of the base 71 to form a first connecting portion and a second connecting portion. Each of the first connecting portions is formed in a staircase shape, has a high position and a low position, and has a low position surface-connected to the circuit board. The lead 74 of the coil 70 is connected to the second connection portion 73B of the two terminals 73, and the two chip-shaped capacitors 75 are connected to the first connection portion 73A of the terminal 73 to which the coil 70 is connected and the remaining portion. Two terminals 7
It is connected between the three first connecting portions 73A. At this time, the chip-shaped capacitor 75 is connected to the high position of the first connecting portion 73A. The two terminals 73 to which the coil 70 is connected function as an input terminal and an output terminal, and the remaining two terminals 73 function as ground terminals to form a low-pass filter shown in the circuit diagram of FIG.

In the LC filter of this embodiment, the first connecting portion also serves as the third connecting portion, and it is not necessary to separately provide the third connecting portion.
Further, since the capacitor 75 and the terminal 73 can be connected to each other on the side surface of the base 71, there is an advantage that the connecting work is easier than the case of using the recess.

As described above, the LC filter of the present invention can be variously modified including a complicated circuit configuration.

When there are a plurality of coils in the embodiment, each coil is appropriately wound around another core or a common core.

The LC filter of the present invention has a plurality of terminals, each having a first connecting portion connected to a circuit board, a second connecting portion connecting a coil lead, and a third connecting portion connecting a capacitor, embedded in a base. In some cases, a plurality of terminals having one connection portion and a second connection portion are embedded. When there are only two connecting portions, the first connecting portion also serves as the third connecting portion.

In each case, only some of the three connecting portions may be required, or terminals having only the required some connecting portions may be mixed. Such terminals are the terminals of FIG.
36, terminal 59 and terminal 57 in FIG. 7 correspond.

The shape of the first connecting portion of the terminal is not limited to that of the embodiment, as long as it is exposed to at least one of the side surface of the base and the main surface on the back side. The second connecting portion may be exposed on the side surface of the base as in the embodiment, but may be exposed on the front main surface. After connecting the leads of the coil, it may be bent along the surface of the base. The entire LC filter may be resin-sealed except for the first connecting portion of the terminal. Further, more complicated filters can be configured by connecting the respective filters as a unit.

〔effect〕

As described above, in the LC filter of the present invention, the coil is arranged on the main surface of the base and a plurality of terminals having three connecting portions are embedded in the base. In some cases, a plurality of terminals having two connecting portions and having the third connecting portion also used as the first connecting portion are embedded in the base. Then, by connecting chip-shaped capacitors to the plurality of terminals, the coil and the capacitors are connected via the terminals. Therefore, it is possible to eliminate the disconnection accident between the terminal and the conductor pattern and between the capacitor and the conductor pattern due to the conductor pattern, and it is possible to improve the reliability of the connection. Of course, the number of steps for forming the conductor pattern is unnecessary.

Also, since the second connection part to which the coil lead is connected is independent, when connecting the LC filter to the circuit board, it is less likely that molten solder will touch the lead or heat is applied, so the connection between the lead and the terminal Will be more certain.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of an LC filter of the present invention, FIG. 2 is an exploded perspective view, FIG. 3 is a plan view of a base, FIG. 4 is a circuit diagram, and FIGS. A perspective view and a circuit diagram of a base showing another embodiment of the LC filter of the invention, FIGS. 7 and 8 are a plan view and a circuit diagram of the base showing another embodiment of the LC filter of the invention, and FIG. Is a perspective view showing still another embodiment of the LC filter of the present invention, and FIG. 10 is a perspective view of a conventional LC filter. 10: Coil, 11, 12: Capacitor, 13-16: Terminal, 17: Base, 18: Main surface, 19: Recess

Claims (1)

(57) [Claims] 1. A coil wound around a core, a base on which the coil is disposed on a main surface, and a plurality of terminals embedded in the base, wherein the plurality of terminals are each formed in an L shape. One end is exposed from the side surface of the base, and a first connecting portion is formed so as to be surface-connected to the circuit board in a stepwise manner, and the other end is exposed to a side surface different from the side surface where the first connecting portion of the base is exposed. The LC filter is characterized in that a second connection portion for connecting the lead of the coil is formed, and a chip-shaped capacitor is connected to a position higher than the first connection portion of a predetermined terminal.