KR930006839Y1 - Emi preventing filter for surface mounting - Google Patents

Abstract

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Description

EMI Filters for Surface Mount

1 is an explanatory diagram of a conventional EMI filter structure.

2 is an explanatory diagram of the structure of the EMI filter for surface mounting of the present invention.

Figure 3 is an exploded perspective view of the filter structure for explaining the present invention.

* Explanation of symbols for main parts of the drawings

20: cover 22-26: guide piece

28, 30: chip ferrite 28a, 28b, 30a, 30b, 32a, 32b, 42, 44, 46: electrode

32: chip capacitor 40: substrate

The present invention relates to a surface mount EMI protection filter for removing high frequency noise components included in signals on PCB patterns or I / O cables in digital devices.

Recently, EMI (Electro Magnetic Interference) caused by an increase in clock signal frequency due to the increase in speed of digital devices has a serious problem.

Frequency signals below 30MHz normally propagate along the conductive line, but frequencies above 30MHz propagate in the air besides the conductive line. Therefore, the signal flowing through the I / O cable of the ultra-high speed digital device is unnecessary to the peripheral device, causing a malfunction in the peripheral device.

To solve this problem, the noise component included in the signal has been removed so far by using a three-terminal noise filter as shown in FIG.

That is, in the conventional three-terminal noise filter structure, the lead 10 is inserted into the hollow of the ferrite beads 14 and 16, and the electrode 12a is disposed at both ends of the lead 10 between the ferrite beads 14 and 16. , The upper electrode 12a of the chip capacitor 12 having the 12b) formed thereon was formed in a T-shape so that the signal component was passed through the input / output cable and the noise component was removed.

However, since the conventional filter as described above includes the lead 10, not only the noise bypass effect caused by the capacitor can be sufficiently utilized by the inductance component of the lead, but also the connection to the ground is made through the lead. The noise reduction effect is not enough.

The present invention was devised to improve the conventional problems as described above, and its purpose is to enable surface mounting of a PCB prevention filter, thereby improving workability when mounted on a PCB substrate, It is to provide EMI filter for surface mount which can enhance reinforcement and noise reduction effect.

The present invention filter is implemented through a substrate provided with an electrode, a pair of chip ferrites and chip capacitors provided with electrodes at upper and lower ends, and a cover part for connecting the upper electrodes of the chip ferrites and chip capacitors and providing good workability. .

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is an explanatory view of the branch of the EMI filter for surface mount according to the present invention, and FIG. 3 is an exploded perspective view of FIG. 2 and shows the left and right sides of the chip capacitor 32 having the electrodes 32a and 32b formed on the top and bottom thereof. The lower electrodes 32b and the chip ferrites 30 and 28 of the electrodes 30a and 30b and the capacitor 32 and the lower electrodes 32b of the chip capacitor 32 are disposed on the right and the lower sides, respectively. Electrodes 42, 44 and 46 are formed on the substrate 40 to which the lower ends 30b and 32b of the chip ferrites 30 and 28 are in contact with each other, and are fixed on the substrate 40 by soldering.

In addition, three pairs of guide pieces 22, 24, and 26 are provided with a cover portion of a metal material formed in the vertical direction, so that the chip ferrites 30, 28 and the chip capacitor 32 are formed on the guide pieces 22, 24, and 26, respectively. The upper part is positioned to be fixed by soldering.

Referring to the operation and effects of the present invention composed of such a structure as follows.

That is, as shown in FIG. 2 and FIG. 3, first, chip pairs 30, 28, and chip capacitors are provided on three pairs of guide pieces 22, 24, and 26 provided in the cover 20 of metal. 32), the chip ferrite 28 is placed and then soldered.

This implements a T-type EMI prevention filter having two inductance components by the chip ferrites 30 and 28 and a capacitance component by the chip capacitor 32.

However, there is a fear of damage because this alone is weak mechanical stability for shape maintenance.

Therefore, the chip ferrites 30 and 28 forming the T-type filter and the lower electrodes 30b, 28b and 32b of the chip capacitor 32 are aligned with the electrodes 42, 44 and 46 on the substrate 40 and soldered. Thus, the surface mount of the stable structure to implement the EMI filter.

As described above, the terminal-type EMI filter of the present invention can be surface-mounted, thereby improving workability when mounted on a PCB, and reinforcing the grounding of the capacitor by connection of a surface electrode. This increases the noise removal effect through the removal of the L component, and also shows an excellent effect that no epoxy molding work is required to fix the ferrite beads and the lead.

Claims (1)

In a ferrite filter for preventing EMI, a pair of upper and lower electrodes 30a, 30b and 28a, 28b are formed on the left and right sides of the chip capacitor 32 provided with the electrodes 32a, 32b at the upper and lower ends thereof. The chip ferrites 30 and 28 are disposed, and a lid portion 20 having three positioning vertical guide pieces 22, 24, and 26 formed thereon is provided thereon to provide the chip capacitor 32 and chips on both sides thereof. Upper portions of the ferrites 30 and 28 are fixed to the vertical guide pieces 22, 24 and 26 by soldering, and electrodes 42, 44 and 46 are disposed below the chip capacitor 32 and the chip ferrites 30 and 28. ) And the lower electrode 32b of the chip capacitor 32 and the lower electrodes 30b and 28b of the chip ferrites 30 and 28 are disposed on the substrate 40 having the substrate 40 formed thereon. EMI shielding filter for surface mounting, characterized in that fixed to the soldering).