JPS63213997A - Circuit device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a circuit device with noise countermeasures.

[Prior Art] As shown in FIG. 6, a T-type LC filter has two inductance elements L1 connected in series to a signal transmission line.
, L2, and a capacitor c1 connected between their intermediate point and ground.

Inductance elements L1 and L2 of this LC filter
has already been constructed by inserting conductive wires into ferrite beads.

[Problems to be Solved by the Invention] By the way, when a computer circuit has a large number of signal transmission paths and a T-type LC filter must be connected to each signal transmission path, it is necessary to Two times the number of ferrite beads are required, making assembly of the filter troublesome. In addition, it is difficult to make ferrite beads extremely compact with mass production, and T-type LC
There were limits to the miniaturization of filters. Furthermore, ferrite
As beads become smaller, the volume of ferrite decreases, making it impossible to obtain a sufficient noise absorption effect.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a circuit device that can easily configure a large number of filters with excellent noise absorption effects.

[Means for Solving the Problems] The present invention for solving the above problems and achieving the above objects will be described with reference to the reference numerals in FIGS. 1 to 5 showing embodiments. 1, a circuit component 2 disposed on the substrate 1, and a connector 3 for connecting an electric circuit including the circuit component 2 to an external circuit. In the circuit device, the lead 7 is electrically connected to the substrate 1, and a plurality of through holes corresponding to the leads 7 are provided between the main body of the connector 3 and the substrate 1. Hole 1
I having 5 or more magnetic blocks 11.14
and a plurality of through holes 17 corresponding to the leads 7!
A plurality of individual electrodes 18 to obtain a plurality of capacitors 18
and one or more dielectric substrates 12 provided with one ground electrode, and pass the sword 7 through the through hole 15 of the magnetic block 11.12 and the through hole 17 of the dielectric substrate 12. , connect the individual electrode 18 to the lead 7, and connect the ground electrode 19 to the circuit board 1.
The present invention relates to a circuit device characterized in that the circuit device is connected to a ground conductor 21 by a conductor member.

"Function" In the above invention, the magnetic block 11 surrounding the lead 7
．． 14 functions as a magnetic core of the inductance element, and the combination of the lead 7 and the magnetic block 11.14 forms an inductance element, and the combination of this and the capacitor suppresses noise conducted through the lead 7 and/or radiation noise. Ru.

The magnetic blocks 11 and 14 also function as electromagnetic noise absorbers, suppressing noise radiated to the outside from the leads 7, noise entering the leads 7 from the outside, and electromagnetic interference between the leads 7.

[Embodiment] Next, an electronic circuit device according to an embodiment of the present invention will be described with reference to FIGS. 1 to 5. This electronic circuit device includes a plurality of circuit components 2 mounted on an insulating circuit board 1, a connector 3 for connecting an electric circuit including the circuit components 2 to an external electronic circuit device, and further according to the present invention. It is constructed by mounting a T-shaped LC filter assembly 4.

The connector 3 includes a main body 5 made of an insulating material, a large number of coupling parts 6 held in the main body 5, and the coupling parts 6.
It consists of a large number (20 in this example) of leads 7 derived from. Each lead 7 has a portion 7 a led out parallel to the substrate 1 and a portion 7 b extending perpendicularly to the substrate 1 , and is inserted into a through hole 8 of the substrate 1 and connected to a connecting conductor 9 provided on the substrate 1 . is fixed with solder 10. The pitch of the lead 7 is 2111, and the diameter of the lead 7 is 0.9 n.
It is m.

The filter assembly 4 includes a first magnetic block 11, a capacitor block including a dielectric substrate 12, and a ground plate 1.
3 and a second magnetic block 14.

``The first and second magnetic blocks 11.14 are made of ferrite cores, and each has a large number (20 in this example) of through holes 15.16 corresponding to the arrangement of the words 7.

The first and second magnetic blocks 11.14 are N
! Connector 3 is made by adding a binder to Zn-based ferrite material, granulating it, dry molding it, and taking into account shrinkage due to firing.
The hole is fired after forming a through hole 15.16 by drilling to match the lead 7, has a magnetic permeability of about i ooo, and has a length of 45 m1'1. Width 51'111. Thickness 3I
It has dimensions of.

The dielectric substrate 12 constituting the capacitor block has a large number of through holes 17 corresponding to the leads 7, and a large number of individual electrodes 18 surrounding the through holes 17 on one main surface 12a.
and has a common ground electrode 19 on the other main surface 12b. The individual poles 18 are separated from each other and arranged adjacent to the through hole 17, as shown in FIG. As shown in FIG. 5, the ground electrode 19 is provided at a position slightly spaced apart from the through hole 17, and has a portion facing each individual '5tf18. This dielectric substrate 12 is made of SrTi 0
A green sheet with a thickness of about 111 mm was made using wet molding using 3-type materials, and after forming through holes 17 with a punch according to the pitch of the leads 7 in anticipation of shrinkage, it was fired to a length of 50 Ill. , width 7IllN, thickness 0.85
This is a 1-all ceramic dielectric substrate. Note that the dielectric constant of this dielectric substrate 12 is approximately 30,000.

The individual electrodes 18 and the ground electrode 19 are formed by screen printing Ag paste on the dielectric substrate 12 and firing it. The capacitance of each capacitor corresponding to each lead 7 is approximately 1000 pF.

The ground plate 13 has a notch 20 for inserting the lead 7.
, and has a main surface portion 13 a corresponding to the ground electrode 19 of the dielectric substrate 12 . Further, in order to connect the circuit board 1 to the ground wiring conductor 21, the ground plate 13 has a pair of legs 13b and 13c.

When assembling the filter assembly 4, each lead 7 of the connector 3 is inserted into each through hole 15 of the first magnetic block 11.
Insert each into. On the other hand, the ground voltage f! of the dielectric substrate 12! 19 to which the ground plate 13 is soldered is prepared, and cream solder (not shown) is applied to the individual electrodes 18. Thereafter, each lead 7 is inserted into each through hole 17 of the dielectric substrate 12 and heated to melt the cream solder and solder each individual electrode 18 to each lead 7. Note that instead of using cream solder, the individual electrodes 18 may be connected to the leads 7 using a solder plating layer or a solder ring.

Next, each lead 7 is inserted into each through hole 16 of the second magnetic block 14, and each lead 7 is further inserted into each through hole 8 of the circuit board 1, and connected to the wiring conductor 9 with solder 10. At this time, the legs 13b and 13c of the ground plate 13 are also inserted into the through holes 22, 23 of the circuit board 1, and connected to the ground conductor 21 by solder 24.

In order to investigate the noise absorption effect of the unit filters in the filter assembly 4, an electronic circuit device configured using the circuit board 1 is assumed to be a personal computer, and the interface connector 3 shown by the broken line in FIG. 3 is connected to the connector 3. Connect the connector terminal 26 of the couple 25 and keep the other end of this cable 25 open to comply with FCC regulations. lH
The amount of radiation noise from z to 240MHz is measured using the 3m method, open
Measured on site. Due to the open site, broadcast waves incident from outside were excluded and only the typical noise level was determined, and the results shown in FIG. 7(C) were obtained. That is, 60MHz to 70MHz, 120MHz
24-30 dB between z and 160 Htlz, cz
Clock noise suppressed to about V/m was observed.

“Due to the relative softness, when noise was measured in a similar manner by omitting the filter assembly 4, the results shown in FIG. 7(A) were obtained.Also, in place of the magnetic blocks 11 and
A ferrite bead with an outer diameter of 1.9 nn, an inner diameter of 11, and a height of 511 ff was attached to each lead 7, and a separate toopr magnetic capacitor was connected between lead 7 and ground, and the noise was measured in a similar manner. As a result, Figure 7 (B
) The results shown are obtained. When attaching a ferrite bead to each lead 7 in Fig. 7(B), 30 to 40 d
Clock noise of about B8V/m is observed. Therefore, by using the filter assembly 4 of this embodiment, compared to the case of no noise countermeasure shown in FIG.
0 dB, uV/m, which is improved by about 5 to 10 dBllV/m compared to the case of the ferrite beads shown in FIG. 7(B). Furthermore, the effect of suppressing noise that appears between clock noises (interference noise of various noises) will be examined. The solid line in FIG. 8 shows the clock noise and the noise in between when no noise countermeasure is taken, and the dotted line shows the noise in the case of this embodiment. As mentioned above, suppressing radiation noise means that lead 7
This also means that conduction noise that penetrates into external electronic circuit devices through the cable 25 is also suppressed. This also means that noise entering the electrical circuit on the circuit board 1 from an external electronic circuit device through the connector 3 can also be suppressed.

The noise absorbing device of this embodiment has the following advantages.

(1) Even if the pitch of the leads 7 of the connector 3 is small, the first and second magnetic blocks 11.14
Since it is only necessary to provide through holes 15 and 16 corresponding to the leads 7 in the beads, they can be manufactured more easily than ferrite beads.

(2) Since the volume of the ferrite surrounding the lead 3 is larger than that in the case of ferrite beads, a large noise absorption effect can be obtained. Further, since the spaces between the leads 7 are filled with ferrite, the effect of suppressing electromagnetic interference between the leads 7 is increased.

(3) Through hole 15.1 of magnetic block 11.14
6 and the through holes 17 of the dielectric substrate 12 are formed to correspond to the leads 7, so that a large number of leads 7 can be inserted into each of the through holes 15, 16, and 17 at once.

Therefore, the filter assembly 4 can be easily installed.

(4) The filter assembly 4 is connected to the main body 5 of the connector 3.
Since it is disposed between the connector 3 and the substrate 1, integration with the connector 3 can be easily achieved. Further, since the first and second magnetic blocks 11.14 surround the leads 7 so as to reduce the exposed portions of the leads 7, noise radiation from the leads 7 can be suppressed.

(5) Since the grounding plate 13 is placed under the dielectric substrate 12, not only is the grounding ensured, but also the effect of reinforcing the dielectric substrate 12 is produced.

(6) Prepare a connector 3 that can be used for both electronic circuit devices that require noise prevention and electronic circuit devices that do not, and attach the filter assembly 4 only when noise prevention is required. Therefore, the mass productivity of the connector 3 is improved, and the cost of the circuit device is reduced.

[Modifications] The present invention is not limited to the above-described embodiments, and, for example, the following modifications are possible.

(1) A portion 13d rising in the opposite direction to the legs 13b and 13c is provided on the ground plate 13, and this rising portion 13
The upper position of the first magnetic block 11 may be limited by the hook portion 13e d.

(2) In order to stabilize the connection between the main body part 5 of the connector 3 and the board 1, a notch may be provided in the board 1, and the protrusion provided with the main body part 5 may be inserted into the notch.

(3) The connector 3 may be fixed to the circuit board 1 with adhesive. In addition, the first and second magnetic blocks 1
1.14 may be fixed to the lead 7 with adhesive.

(4) The first and second magnetic blocks 11.14 may be formed of a mixture of magnetic powder and resin or a magnetic material other than ferrite.

(5) One of the first and second magnetic blocks 11.14 may be omitted to provide an L-shaped filter configuration.

Further, it is also possible to use two or more dielectric substrates 12 having capacitor electrodes, or to combine two dielectric substrates 12 and one magnetic block 11 to form a π-type filter.

(6) Connect lead 7 to ground plate 13 instead of wire 20.
A hole with a large diameter corresponding to the diameter may be provided.

(7) Provide a through hole for grounding in the dielectric substrate 12,
A pin connected to the ground conductor 21 of the circuit board 1 may be passed through this through hole, and the ground electrode 19 may be connected to this pin.

[Effects of the Invention] As is clear from the above, according to the present invention, a circuit device including a filter having a large noise absorption effect can be easily constructed.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view showing a part of a circuit device according to an embodiment of the present invention, Fig. 2 is a front view of the circuit device, and Fig. 3 is a partial cutaway taken along the line ■-■ in Fig. 2. A cross-sectional view shown, ? Figure R4 is a plan view showing a part of the dielectric substrate with individual electrodes, Figure 5 is a bottom view of a part of the dielectric substrate with a ground electrode, and Figure 6 is a circuit diagram showing a T-type LC filter. , Fig. 7 is a diagram showing the relationship between frequency and noise level, Fig. 8 is a diagram showing the noise level in some frequency regions, and Fig. 9 is a perspective view showing a part of a modified earth plate. be. DESCRIPTION OF SYMBOLS 1... Circuit board, 3... Connector, 4... Filter assembly, 5... Main body part, 6... Coupling part, 7...
Lead, 8... Through hole, 9... Conductor, 11... First magnetic block, 12... Dielectric substrate, 13...
・Earth plate, 14...Second magnetic block, 1u,
16.17...Through hole, 18...Individual electrode, 19.
...Earth electrode.

Claims (1)

[Claims] 1. A circuit board (1), a circuit component (2) arranged on the board (1), and a connector for connecting an electric circuit including the circuit component (2) to an external circuit. (3) Consisting of
The circuit device in which the connector (3) has a plurality of leads (7) led out from the connector main body (5), and the leads (7) are electrically connected to the substrate (1), A plurality of through holes (1) corresponding to the leads (7) are provided between the main body (5) of the connector (3) and the substrate (1).
5) one or more magnetic blocks (11) (
14), and a plurality of through holes (
17) and at least one or more dielectric substrates (12) provided with a plurality of individual electrodes (18) and a ground electrode (19) for obtaining a plurality of capacitors; 7) to the magnetic blocks (11) (14).
) and the through hole (17) of the dielectric substrate (12), connect the individual electrode (18) to the lead (7), and connect the ground electrode (19) to the circuit board. A circuit device characterized in that it is connected to the ground conductor (21) of (1) by a conductor member.