JPH03120805A - Lc filter - Google Patents
Lc filterInfo
- Publication number
- JPH03120805A JPH03120805A JP25908389A JP25908389A JPH03120805A JP H03120805 A JPH03120805 A JP H03120805A JP 25908389 A JP25908389 A JP 25908389A JP 25908389 A JP25908389 A JP 25908389A JP H03120805 A JPH03120805 A JP H03120805A
- Authority
- JP
- Japan
- Prior art keywords
- hole
- filter
- main body
- electrode
- conductor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 229910000859 α-Fe Inorganic materials 0.000 claims abstract description 16
- 239000004020 conductor Substances 0.000 claims abstract description 12
- 239000000203 mixture Substances 0.000 claims abstract description 10
- 238000004519 manufacturing process Methods 0.000 abstract description 5
- 229910007565 Zn—Cu Inorganic materials 0.000 abstract description 4
- 239000010949 copper Substances 0.000 abstract description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 abstract description 2
- 229910052802 copper Inorganic materials 0.000 abstract description 2
- 239000002184 metal Substances 0.000 abstract description 2
- 229910052751 metal Inorganic materials 0.000 abstract description 2
- 229910052709 silver Inorganic materials 0.000 abstract description 2
- 239000004332 silver Substances 0.000 abstract description 2
- 230000000149 penetrating effect Effects 0.000 abstract 1
- 230000035699 permeability Effects 0.000 description 7
- 239000003990 capacitor Substances 0.000 description 6
- 238000010586 diagram Methods 0.000 description 3
- 239000003989 dielectric material Substances 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 239000000696 magnetic material Substances 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 229910052725 zinc Inorganic materials 0.000 description 2
- 239000000654 additive Substances 0.000 description 1
- 230000002238 attenuated effect Effects 0.000 description 1
- 239000011324 bead Substances 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 238000011282 treatment Methods 0.000 description 1
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は、信号ラインの電磁干渉防止対策上設けられる
低域フィルタに関する。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a low-pass filter provided as a measure to prevent electromagnetic interference in a signal line.
（従来の技術）
コンピュータのリード線等に取付けられてノイズの侵入
を防止する従来のＬＣフィルタは、一般に、誘電体から
なるコンデンサと磁性体からなるインダクタか別々に構
成されている。そしてコンデンサは、リート線に外嵌し
た誘電体からなるビーズの外周に電極を設け、その電極
を接地し、インダクタはり−ト線に筒形をなす磁性体を
外嵌してなる。(Prior Art) A conventional LC filter that is attached to a computer lead wire or the like to prevent noise from entering the filter is generally configured with a capacitor made of a dielectric material and an inductor made of a magnetic material separately. The capacitor is constructed by providing an electrode on the outer periphery of a bead made of a dielectric material fitted around a wire, the electrode being grounded, and a cylindrical magnetic material being fitted around the inductor wire.
ＬＣフィルタとして、特開平Ｌ−２２９７４号公報に開
示されているように、半導体性を有するフェライトてな
る筒形フィルタの外周に絶縁層を形成し、その絶縁層の
表面と、フェライトの貫通孔の内周面に電極を形成し、
貫通孔に導体を貫挿し、内外の電極と絶縁層との間でコ
ンデンサを形成し、フェライトによりインダクタを形成
したものが提案されている。As an LC filter, as disclosed in Japanese Patent Laid-Open No. 22974, an insulating layer is formed around the outer periphery of a cylindrical filter made of ferrite having semiconductor properties, and the surface of the insulating layer and the through-hole of the ferrite are Form an electrode on the inner peripheral surface,
It has been proposed that a conductor is inserted into the through hole, a capacitor is formed between the inner and outer electrodes and the insulating layer, and an inductor is formed using ferrite.
（発明が解決すべき課題）
コンデンサとインダクタとを別体に構成したＬＣフィル
タは１部品点数か多く、取付はスペースか大となる上、
製造コストも高くなるという問題点かあった。また、特
開平１−２２９７４号公報に開示されたＬＣフィルタは
、コンパクト化される利点はあるか、半導体性フェライ
トの表面を再酸化処理したり、金属酸化物を表面に塗布
して空気中で熱処理する等の処理を必要として、製造工
程数か多くなるいう問題点かあった。(Problem to be solved by the invention) An LC filter in which a capacitor and an inductor are configured separately has a large number of parts, and installation requires a large amount of space.
There was also the problem that manufacturing costs were high. Also, does the LC filter disclosed in Japanese Patent Application Laid-Open No. 1-22974 have the advantage of being compact? It may be possible to re-oxidize the surface of the semiconducting ferrite or coat the surface with metal oxide to allow it to be stored in the air. There was a problem in that it required heat treatment and other treatments, which increased the number of manufacturing steps.
本発明は、このような問題点を解決し、部品点数か少な
く、かつ製造工程も簡単となるＬＣフィルタを提供する
ことを目的とする。SUMMARY OF THE INVENTION An object of the present invention is to solve these problems and provide an LC filter with a small number of parts and a simple manufacturing process.
（課題を解決するための手段）
上記の目的を達成するため１本発明は、ＮｉｗＺｎｘＣ
ｕＪ（！ｚ０４： ０ 、０５≦ｗ≦０．９５．０．０
５≦ｘ≦０．９５．０．０５≦ｙ≦０．９５．１．８≦
２≦２．０なる組成の筒形フェライトを素子本体とし、
該素子本体の中心の貫通孔の表面および外表面に電極を
形成し、前記貫通孔に導体を貫挿してなることを特徴と
する。(Means for Solving the Problems) In order to achieve the above object, the present invention provides NiwZnxC.
uJ(!z04: 0, 05≦w≦0.95.0.0
5≦x≦0.95.0.05≦y≦0.95.1.8≦
A cylindrical ferrite having a composition of 2≦2.0 is used as the element body,
It is characterized in that electrodes are formed on the surface and outer surface of a through hole at the center of the element body, and a conductor is inserted into the through hole.
（作用）
本発明によるＬＣフィルタは、素子本体か前記組成を有
し、透磁率が高いためにインダクタとしての機能を発揮
すると共に、所望の値以上の誘電率が得られ、抵抗率も
高いため、コンデンサとしての機悌も発揮する。(Function) The LC filter according to the present invention has the element body having the above-mentioned composition, and has a high magnetic permeability, so it functions as an inductor, and also has a dielectric constant higher than a desired value, and has a high resistivity. , it also demonstrates its resourcefulness as a capacitor.
（実施例）
第１図は本発明によるＬＣフィルタの一実施例を示す縦
断面図、第２図は本実施例の横断面図である。１は導体
、２はＬＣフィルタであり、該ＬＣフィルタ２は、フェ
ライトでなる素子本体３の中央に前記導体ｌを貫挿する
貫通孔４を有し、その貫通孔４の内面に導体ｌを接触さ
せる電極５を形成し、表面にも電極６を形成してなる。(Example) FIG. 1 is a longitudinal cross-sectional view showing an example of an LC filter according to the present invention, and FIG. 2 is a cross-sectional view of the present example. 1 is a conductor, and 2 is an LC filter. The LC filter 2 has a through hole 4 in the center of an element body 3 made of ferrite, into which the conductor l is inserted, and the conductor l is inserted into the inner surface of the through hole 4. An electrode 5 is formed for contact, and an electrode 6 is also formed on the surface.
これらの電極５．６は、銀、銅等の金属膜を焼付は等に
よって形成することにより構成される。素子本体３は、
Ｎ １−Ｚｎ−Ｃｕ系フェライトからなる。These electrodes 5.6 are constructed by forming a metal film of silver, copper, etc. by baking or the like. The element body 3 is
It is made of N1-Zn-Cu type ferrite.
第３図は前記電極６を接地した場合の等価回路図であり
、ＬはこのＬＣフィルタにおいて、フェライトでなる素
子本体３によってもたらされるインダクタンス、Ｃは素
子本体３の誘電体としての作用により得られるキャパシ
タンスである。FIG. 3 is an equivalent circuit diagram when the electrode 6 is grounded, where L is the inductance provided by the element body 3 made of ferrite in this LC filter, and C is the inductance provided by the element body 3 acting as a dielectric. It is capacitance.
第２図において、ａはリート線の半径、ｂはフィルタ２
の半径である。この構成において、インダクタンスし、
キャパシタンスＣはそれぞれ下記のように表わされる。In Fig. 2, a is the radius of the Riet line, and b is the filter 2.
is the radius of In this configuration, the inductance is
Each capacitance C is expressed as follows.
Ｌ＝ （ｅ／２π） ｌｏｇ（ｂ／ａ） ［
Ｈ／ｍコたたし、μ：透磁率
Ｃ＝２ｒ＠／ ｌｏｇ（ｂ／ａ）［Ｆ／ｍ］ただし、ε
：誘電率
ここで、コンピュータ等においては、一般にａ＝Ｏ０・
ｌ■〜０．３ｍｍであり、また、フェライトでなる素子
本体３の強度上、電極５．６の厚さを無視したときの厚
さ（ｂ−ａ）は０．５ｍｍ程度以上必要とされ、また小
型化の面から、ｂ＝０．９ｍ−〜１．８＠ｍ程度に設定
される。L= (e/2π) log(b/a) [
H/m, μ: Magnetic permeability C=2r@/log(b/a) [F/m] However, ε
: Dielectric constant Here, in computers etc., generally a=O0・
1 ~ 0.3 mm, and due to the strength of the element body 3 made of ferrite, the thickness (ba) when ignoring the thickness of the electrode 5.6 needs to be about 0.5 mm or more, Further, from the viewpoint of miniaturization, b is set to approximately 0.9 m to 1.8 m.
一方、コンピュータ等においては、１ｏＯＨｚ程度以上
の周波数の雑音が２０ｄＢ程度以上減衰することが要求
されることを考慮すれば、素子本体３の長さｕ＝１．０
ｍ■〜９．Ｏｌ−とすれば、インダクタンス値りとして
１００ｎＨ〜４５０ｎｌｌ、キャパシタンス値Ｃとして
１ｏｐＦ〜１６ｐＦ程度が必要となり、このような値を
得るには、透磁重用は５０以上、誘電率εは１０以上必
要となる。また、損失を極力小さくするためには、抵抗
率は１０’ΩＣ■以上であることか望まれる。On the other hand, considering that in computers, etc., it is required that noise at frequencies of about 1oOHz or higher be attenuated by about 20 dB or more, the length of the element body 3 u = 1.0
m■～9. For Ol-, the inductance value needs to be 100 nH to 450 nll, and the capacitance value C needs to be about 1 opF to 16 pF. To obtain these values, the magnetic permeability value needs to be 50 or more, and the dielectric constant ε needs to be 10 or more. Become. Further, in order to minimize loss, it is desirable that the resistivity be 10'ΩC or more.
このような特性のＬＣフィルタを得るため、試作を次の
ような工程で行なった。In order to obtain an LC filter with such characteristics, a prototype was produced through the following steps.
（１）まず、 Ｎｉ−Ｚｎ−Ｃｕ系フェライト材を用い
て筒形の素子本体３を成形する。(1) First, a cylindrical element body 3 is molded using a Ni-Zn-Cu ferrite material.
（２）成形したものを焼成する。(2) Fire the molded product.
（３）素子本体３の筒内及び外周に電極部５，６を焼き
付けまたはメツキで形成する。(3) Electrode parts 5 and 6 are formed inside the cylinder and on the outer periphery of the element body 3 by baking or plating.
（４）貫通孔４内に導体ｌを設ける。(4) A conductor l is provided in the through hole 4.
第４図は、素子本体３の組成をＮ ｉｗＺｎｘｃｕｖＦ
ｅｚＯ＜で表した場合、ＮｉとＺｎとの比ｗ：ｘを一定
（１：１）、ｚ＝１．９５とし、ＮｉとＺｎに対してＣ
ｕを置換させた場合の組成の変化に対する透磁率μ、誘
電率εおよび抵抗率ρの値の変化を示すものである。FIG. 4 shows the composition of the element body 3 as N iwZnxcuvF.
When expressed as ezO<, the ratio w:x of Ni and Zn is constant (1:1), z=1.95, and C for Ni and Zn.
It shows changes in the values of magnetic permeability μ, dielectric constant ε, and resistivity ρ with respect to changes in composition when u is replaced.
また、：５５図は、第４図において、透磁率ル１、Ａ電
率εおよび抵抗率ρの値の面で最適と思われるＣｕの置
換量であるｙを一定（ｙ＝０．２）とし、また、Ｆｅの
星ｚを一定（ｚ＝１．９５）とした場合において、ｗ：
ｘの比を種々に変化させた場合の透磁車路、誘電率εお
よび抵抗率ρの値の変化を示すものである。Also, Figure 55 shows that in Figure 4, y, which is the optimum amount of Cu replacement in terms of the values of magnetic permeability 1, A electric constant ε, and resistivity ρ, is kept constant (y = 0.2). And when the Fe star z is constant (z = 1.95), w:
It shows changes in the values of the permeable roadway, dielectric constant ε, and resistivity ρ when the ratio of x is varied.
また、第６図は、ｗ：ｘ：ｙ＝２：２：１とし、Ｆｃの
ｊｌＭ Ｚを種々に変化させた場合の透磁率ル、誘電率
εおよび抵抗率ρの値の変化を示すものである。In addition, Fig. 6 shows the changes in the values of magnetic permeability, dielectric constant ε, and resistivity ρ when w:x:y=2:2:1 and jlMZ of Fc is variously changed. It is.
第４図ないし第６図から、透磁率ｐ、誘電率εおよび抵
抗率ρの値か上述のイ１を満足する各元素の組成は０．
０５≦ｗ≦０．９５．０．０５≦ｘ≦０．９５，０．０
５≦ｙ≦０．９５，１．８≦２≦２．０なる範囲である
。なお、必要に応じて微量の添加物を加えることもある
。From FIG. 4 to FIG. 6, the composition of each element satisfying the above-mentioned A1 is 0.
05≦w≦0.95.0.05≦x≦0.95,0.0
The range is 5≦y≦0.95, 1.8≦2≦2.0. Note that trace amounts of additives may be added as necessary.
（発明の効果）
本発明によれば、Ｎｉ−Ｚｎ−Ｃｕ系筒形フェライトの
組成を前述の範囲に設定することにより、１個の素子で
インダクタとコンデンサを構成することができるから、
部品点数の減少、取付はスペースの縮小か達成される。(Effects of the Invention) According to the present invention, by setting the composition of the Ni-Zn-Cu-based cylindrical ferrite within the above-mentioned range, an inductor and a capacitor can be constructed with one element.
A reduction in the number of parts and installation space is achieved.
また本発明のＬＣフィルタは、フェライトの表面の絶縁
化等の工程を必要としないため、製造工程数が少なく、
安価に提供できる。Furthermore, since the LC filter of the present invention does not require any steps such as insulating the surface of the ferrite, the number of manufacturing steps is small.
Can be provided at low cost.
第１図は本発明によるＬＣフィルタの一実施例を示す縦
断面図、第２図はその横断面図、第３図は該ＬＣフィル
タの等価回路図、第４［間ないし第６図は本発明におい
て、種々の組成における透磁率、誘電率および抵抗率の
変化を示す図である。
ｌ：導体、２ ： ＬＣフィルタ、３：素子本体、４：
貫通孔、５．６：電極FIG. 1 is a longitudinal cross-sectional view showing an embodiment of the LC filter according to the present invention, FIG. 2 is a cross-sectional view thereof, FIG. 3 is an equivalent circuit diagram of the LC filter, and FIGS. In the invention, it is a diagram showing changes in magnetic permeability, dielectric constant, and resistivity in various compositions. l: conductor, 2: LC filter, 3: element body, 4:
Through hole, 5.6: electrode
Claims (1)
≦ｗ≦０．９５、０．０５≦ｘ≦０．９５、０．０５≦
ｙ≦０．９５、１．８≦ｚ≦２．０なる組成の筒形フェ
ライトを素子本体とし、該素子本体の中心の貫通孔の表
面および外表面に電極を形成し、前記貫通孔に導体を貫
挿してなることを特徴とするＬＣフィルタ。Ni_wZn_xCu_yFe_zO_4:0.05
≦w≦0.95, 0.05≦x≦0.95, 0.05≦
The element body is a cylindrical ferrite having a composition of y≦0.95 and 1.8≦z≦2.0, electrodes are formed on the surface and outer surface of the through hole in the center of the element body, and a conductor is formed in the through hole. An LC filter characterized by being formed by inserting the.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25908389A JPH03120805A (en) | 1989-10-04 | 1989-10-04 | Lc filter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25908389A JPH03120805A (en) | 1989-10-04 | 1989-10-04 | Lc filter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH03120805A true JPH03120805A (en) | 1991-05-23 |
Family
ID=17329082
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP25908389A Pending JPH03120805A (en) | 1989-10-04 | 1989-10-04 | Lc filter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH03120805A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000201042A (en) * | 1999-01-08 | 2000-07-18 | Kankyo Denji Gijutsu Kenkyusho:Kk | Through-type emi filter |
| KR100495871B1 (en) * | 1999-04-23 | 2005-06-16 | 익스팬테크주식회사 | Lead-through type filter with built-in square shape elements |
| JP2009164513A (en) * | 2008-01-10 | 2009-07-23 | Murata Mfg Co Ltd | Electronic component |
-
1989
- 1989-10-04 JP JP25908389A patent/JPH03120805A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000201042A (en) * | 1999-01-08 | 2000-07-18 | Kankyo Denji Gijutsu Kenkyusho:Kk | Through-type emi filter |
| KR100495871B1 (en) * | 1999-04-23 | 2005-06-16 | 익스팬테크주식회사 | Lead-through type filter with built-in square shape elements |
| JP2009164513A (en) * | 2008-01-10 | 2009-07-23 | Murata Mfg Co Ltd | Electronic component |
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