JP2728439B2 - Four-terminal noise filter and method of manufacturing the same - Google Patents

Description

The present invention relates to a noise filter and a method for manufacturing the same, particularly
The present invention relates to a terminal-type noise filter and a method of manufacturing the same.

[Prior Art] With the development of electronic technology in recent years, electronic circuits have been widely used in various fields. Therefore, it is necessary to operate each of these electronic circuits stably and reliably without being affected by outside. desired.

However, noise enters such an electronic circuit directly or indirectly from the outside. For this reason, there is a problem that a malfunction often occurs in various electronic devices using the electronic circuit.

In particular, electronic circuits often use a switching regulator as a DC power supply. Therefore, a large noise having various frequency components is often generated in a power supply line of a switching regulator due to a transient current such as switching or a load fluctuation caused by a switching operation of a digital IC to be used. These noises are transmitted to other circuits in the same device via power supply lines or by radiation, causing adverse effects such as malfunctions and lowering of the S / N ratio. May cause malfunction.

In order to remove such noise, various noise filters are generally used in electronic circuits. In particular, in recent years, various types of high-performance electronic devices have been used, and regulations on noise have become increasingly intense. For this reason, a small and high-performance noise filter capable of reliably removing generated noise. The development of is desired.

One of such noise filters has been
The noise filter shown in FIG. 14B is widely used.

However, in the conventional four-terminal noise filter, as shown in FIG. 14A, two sets of windings 12 and 14 are wound around a core 10 and capacitors 16 and 18 are provided at both ends of these windings 12 and 14, respectively. Each was formed so as to be connected in parallel.

[Problems to be Solved by the Invention] As described above, since the conventional noise filter requires the core 10, the noise filter itself is larger and larger than various types of electronic components which are becoming smaller and lighter in recent years. There was a problem that it would be expensive.

Further, since the conventional four-terminal noise filter is formed as a lumped constant type as shown in FIG. 14 (B), the noise filter alone intrudes into various types of noise, particularly common mode noise such as switching surge and ripple component. Normal mode noise such as can not be reliably removed,
Also, when the capacitance and inductance of the capacitor and the coil are increased, ringing occurs.

The present invention has been made in view of such a conventional problem, and an object of the present invention is to provide a small four-terminal noise filter and a small four-terminal noise filter capable of reliably removing intruding noise without generating ringing or the like. Another object of the present invention is to provide a method of manufacturing the same.

Means for Solving the Problems In order to achieve the above object, the invention according to claim 1 includes a band-shaped conductor having first and second input / output leads connected near both ends; And a band-shaped conductor to which the second inner lead and the second outer lead for output are connected, in a tubular shape via a dielectric sheet,
An air-core type four-terminal noise filter including the first inner lead and the second inner lead as one input / output terminal, and the first outer lead and the second outer lead as the other input / output terminal, A straight line connecting each of the outer leads in a state where the first outer lead and the second outer lead are shifted by about 1/2 turn, and the first inner lead and the second inner lead are shifted by about 1/2 turn. The pressed laminate is pressed flatly from a direction perpendicular to the direction, and the respective leads are formed so as to be substantially aligned.

According to a second aspect of the present invention, a strip-shaped conductor having input / output first inner leads and first outer leads connected near both ends, and an input / output second inner lead and second outer leads connected near both ends. Wrapped in a tubular shape via a dielectric sheet,
An air-core type four-terminal noise filter including the first inner lead and the second inner lead as one input / output terminal, and the first outer lead and the second outer lead as the other input / output terminal, A first outer lead and a second outer lead are shifted by about 1/2 rotation, and a line perpendicular to a line connecting the first inner lead and the second inner lead to the first and second outer leads is drawn. In a state where they are arranged so as to be symmetrical to each other as a symmetric axis, the wound laminate is pressed flatly from a direction orthogonal to a straight line connecting the outer leads, and the respective leads are formed so as to be substantially aligned. It is characterized by having been done.

According to a third aspect of the present invention, a plurality of strip-shaped conductors are stacked via a dielectric sheet to form a laminate, and a first inner lead for input / output and a second inner lead near the inner end of each strip-shaped conductor. A first step of connecting a lead; and winding and winding the laminate a plurality of times around a rotary winding shaft, and inputting and outputting signals in the vicinity of the outer end of each of the strip-shaped conductors so as to be positioned substantially in a straight line through the center of the winding shaft. A second step of connecting the first outer lead and the second outer lead for use, removing the rotary winding shaft from the wound laminated body, and pressing the laminated body from a direction orthogonal to a straight line connecting the both outer leads. A third step of forming each lead into an elliptical shape that is substantially aligned on a straight line. In the first step, the first and second inner leads are substantially aligned on a winding shaft center. Near the inner edge of each strip conductor so that it is located Characterized in that it connects to.

According to a fourth aspect of the present invention, a plurality of strip-shaped conductors are overlapped via a dielectric sheet to form a laminate, and a first inner lead for input / output and a second inner lead near the inner end of each strip-shaped conductor. A first step of connecting a lead; and winding and winding the laminate a plurality of times around a rotary winding shaft, and inputting and outputting signals in the vicinity of the outer end of each of the strip-shaped conductors so as to be positioned substantially in a straight line through the center of the winding shaft. A second step of connecting the first outer lead and the second outer lead for use, removing the rotary winding shaft from the wound laminated body, and pressing the laminated body from a direction orthogonal to a straight line connecting the both outer leads. A third step of forming each lead into an ellipse substantially aligned on a straight line. In the first step, the first and second inner leads are connected to the first and second outer leads. Line perpendicular to the line as the axis of symmetry And wherein placing the initiatives symmetrical.

[Operation] Next, the operation of the present invention will be described.

As shown in FIG. 2, the four-terminal noise filter according to the present invention includes a first input / output terminal near both ends of a strip-shaped conductor 30-1.
The inner lead 34-1 and the first outer lead 34-2 are connected to each other, and second input / output second leads are provided near both ends of another strip-shaped conductor 30-2.
The inner lead 36-1 and the second outer lead 36-2 are connected.

The conductor sheets 30-1 and 30-2 are formed in a tubular shape with the dielectric sheets 32-1 and 32-2 interposed therebetween.

The first inner lead 34-1 and the second inner lead 36-1 are used as one input / output terminal, and the first outer lead 34-2 and the second outer lead 36-2 are used as the other input / output terminal. .

By doing so, the four-terminal noise filter of the present invention functions as a distributed constant type four-terminal noise filter as shown in FIG.

That is, between the lead 34-1 and 34-2, between the inductance L ₁ corresponding to the length and number of turns of the elongate conductive strip 30-1 is obtained, likewise a pair of leads 36-1,36
Between -2 inductance L ₂ corresponding to the length and number of turns of the elongate conductive strip 30-2 is obtained.

In addition, since these band-shaped conductors 30-1 and 30-2 are opposed via the dielectric sheets 32-1 and 32-2, a capacitor having a large distribution constant can be obtained. Therefore, the thus formed tubular noise filter functions as a distributed constant type four-terminal noise filter as shown in the equivalent circuit of FIG.

Thus, the four-terminal noise filter of the present invention functions as a distributed constant type noise filter as shown in FIG. For this reason, the four-terminal noise filter of the present invention can obtain better attenuation characteristics over a relatively wide band as compared with the conventional lumped parameter type four-terminal noise filter, and causes ringing of various noises. Can be removed without the need. In particular, in the four-terminal noise filter of the present invention, the L component of the distribution constant shown in FIG. 3 functions effectively to remove common mode noise.
The C component of the distribution constant shown in FIG. 3 functions effectively, and normal mode noise can be effectively removed.

Further, in the four-terminal noise filter of the present invention, the strip conductors 30-1 and 30-2 are simply formed by the dielectric sheets 32-1 and 32-2.
Since it is formed so as to be wound into a tubular shape through the above, it is possible to simplify the production and to make it extremely small and lightweight.

Further, according to the filter manufacturing method according to the present invention, the plurality of strip-shaped conductors 30-1 and 30-2 are combined with the dielectric sheets 32-1 and 32-2.
-2 is wound around the rotary winding axis a plurality of times, and the stacked bodies are placed outside the respective strip-shaped conductors 30-1 and 30-2 so as to be located substantially in a straight line through the center of the winding axis. A first outer lead 34-2 and a second outer lead 36-2 for input / output are connected near the ends.

Then, the rotary winding shaft is removed from the wound laminate, and the laminate is pressed from a direction orthogonal to a straight line connecting the both outer leads 34-2 and 36-2, and each laminate 34-
An oval shape is formed in which 1, 34-2, 36-1, and 36-2 are substantially aligned.

Thus, according to the present invention, the first and second inner leads 34-1, 36-1 and the first and second outer leads 34-2, 36-2 are always aligned. Because it can be formed, the attenuation characteristics are almost uniform,
A four-terminal noise filter excellent in mass productivity can be obtained.

Furthermore, each lead 34-1, 34-2 aligned in a straight line,
Since the intervals between 36-1 and 36-2 can be set arbitrarily, a four-terminal noise filter that can be easily attached to a substrate can be obtained by making the intervals between these leads equal.

Next, a preferred embodiment of the present invention will be described with reference to the drawings.

First Embodiment FIG. 1 shows a preferred embodiment of a four-terminal noise filter to which the present invention is applied.

In the case of manufacturing the four-terminal type noise filter of the embodiment, first, as shown in FIG.
1, 30-2 are laminated via dielectric sheets 32-1 and 32-2 to form a laminate, and each of the strip-shaped conductors 30-
A first inner lead 34-1 and a second inner lead 36-1 for input and output are provided near the inner ends (left ends in the figure) of the first and second 30-2.
Connect.

In this embodiment, the inner leads 34-1, 36-1
Are positioned substantially in a straight line via a rotation center P of a rotary winding shaft 38 described later.

Next, as shown in FIG. 1 (A), the laminate is wound a plurality of times around a rotary winding shaft 38. At this time, the outer leads 34-2 and 36-2 are substantially aligned with each other via the winding shaft center P.
The first outer lead 34-2 and the second outer lead 36-2 for input / output are connected near the outer ends of the strip-shaped conductors 30-1 and 30-2 so as to be located on the upper side 100.

In the embodiment, each outer lead is placed on an extension of a line including both inner leads 34-1, 36-1 via the rotation center P.
34-2 and 36-2 are formed.

Next, after fixing the winding end of the winding portion 40 with heat welding or an adhesive, the winding portion 40 is pulled out from the winding shaft 38, and is orthogonal to the line connecting the outer leads 34-2 and 36-2. The winding part 40 is pressed while heating from the direction. Thereby, the winding part 40
As shown in FIG. 1 (B), the air core portion 42 extracted from the winding shaft 38 is deformed, and the leads 34-2, 34-1 and 36-
As 1, 36-2 are aligned on a straight line (inline), the interval between the leads is enlarged.

Here, assuming that the radius of the winding shaft 38 is r and the thickness of the winding part 40 is d, if the relational expression of d = (2πr) / 2 = πr is established, the manufactured four-terminal type is obtained. The leads 34-1, 34-2, 36-1, and 36-2 of the noise filter can be equally spaced.

That is, the thickness d of the wound portion 40 is determined by the distance between the leads 34-2 and 34-1 in FIG.
The value is substantially equal to the interval of -2. Furthermore, since the circumference of the winding shaft 38 is represented by 2πr using its radius r,
The interval in the longitudinal direction of the air core 42 is the length of the circumference of the winding shaft 38.
1/2, that is, πr. The length πr of this air core 42
Is substantially equal to the interval between the leads 34-1 and 36-1. Therefore, the leads 34-1, 34-2, 36-1, and 36-2 can be equally spaced by setting the relational expression of d = πr to hold.

1A and 1B, the first inner lead 34-1 and the first outer lead 34-2 are located on the left side of the rotation center P, and the second inner lead 34-2 is located on the right side of the rotation center P. Although the lead 36-1 and the second outer lead 36-2 are formed so as to be located, as shown in FIG.
2. The first inner lead 34-1 and the second outer lead 36-2 may be located on the right side of the second inner lead 36-1 and the rotation center P.

As shown in FIG. 1 (C), the four-terminal type noise filter thus formed has a substantially flat elliptical winding portion 40 and four in-line type noise filters provided on one end surface thereof. 34-2, 34-1, 36-1, and 36-2.

The noise filter may be provided with a casing with a metal foil or the like on the outer surface of the winding portion 40, or with a coating of epoxy or the like as necessary.

As described above, the formed four-terminal noise filter of the present invention is formed into a substantially elliptical shape by winding a band-shaped conductor and pressing it. For this reason, it is smaller and lighter than the conventional four-terminal type noise filter shown in FIG. 14 (A), and it is extremely suitable as an electronic circuit component that has recently been required to be smaller and lighter.

Further, in the four-terminal noise filter of the present invention, since the leads 34-2, 34-1, 36-1, and 36-2 are formed so as to have a sufficient interval from each other, each of the leads 34-2, 34-1, 36-1, and 36-2 is formed.
2, 34-1, 36-1, and 36-2 can be easily attached to the printed circuit board.

In particular, according to the invention, the radius r of the winding shaft 38 used,
By setting the number of turns and the like of the winding portion 40, it is also possible to form the respective lead intervals so that they are equal.
The attachment of the four-terminal noise filter of the embodiment to the printed circuit board can be further facilitated.

Further, according to the present invention, each of the leads 34-2, 34-1, and 36
-1, 36-2 can be reliably arranged on a straight line (inline). Therefore, the four-terminal type noise filter can be more easily attached to the substrate, and can sufficiently withstand external physical stress.
In addition to this, according to the present invention, since the intervals between the leads can be always formed to be constant, variations in the attenuation characteristics of the manufactured four-terminal noise filter are reduced. Therefore, according to the present invention, it is possible to mass-produce a sufficiently small noise filter having substantially uniform attenuation characteristics.

Further, the four-terminal type noise filter of the present invention functions as a distributed constant type noise filter as shown in FIG. 3, and its L component works effectively to effectively remove common mode noise. Further, there is an excellent effect that the C component works effectively and the normal mode noise can be effectively removed, which is not provided by the conventional lumped constant type noise filter.

Second Embodiment FIGS. 5 and 6 show a preferred second embodiment of a four-terminal noise filter according to the present invention. The characteristics of this embodiment are shown in FIG. 6 As shown in FIG.
Outer leads 34-2 and 3-3 on a straight line 100 passing through the rotation center P
6-2 is located at the center P, and the inner leads 34-1 and 36-
1 is located.

Even in this case, FIG. 5 (B) or FIG. 6 (B)
As shown in the figure, by pressing the winding portion 40 in a direction orthogonal to the straight line 100, the linearity is slightly inferior to that of the first embodiment, but each of the leads 34-2, 34-1, 36-1, and It is possible to obtain a four-terminal noise filter in which 36-2 are arranged substantially in a straight line (inline).

In particular, the four-terminal noise filter of the present embodiment
The length of the air core 42 that became flat when the 40 was crushed,
This is effective when the leads are formed at equal intervals when the thickness is twice or more the thickness of the winding portion 40.

That is, in such a case, by appropriately calculating the angle θ between the straight line 100 and the straight line 110 from the relationship between the thickness d of the winding portion 40 and the radius r of the winding shaft 38, FIG. B) or as shown in FIG.
2, 34-1, 36-1, and 36-2 are located on a straight line, and the leads can form a four-terminal noise filter with equal intervals.

The outer leads 34-2, 36 on the straight line 100 in this way.
-2, and the inner leads 34-1, 36-
In the case where 1 is located, it is necessary to take care that these straight lines 100 and 110 do not cross at right angles as shown in FIG. 7 or FIG.

This is because if the straight lines 100 and 110 are orthogonal, the winding 40
Is flattened, as shown in FIG. 7B or FIG. 8B, the inner leads 34-1 and 36-2 face each other via a thin insulator sheet. This is because it is not possible to obtain a proper physical interval, and there is a high risk of short-circuiting due to wiring and soldering work, which makes it unpractical.

In addition, in order to form the leads of the noise filter at equal intervals, as shown in FIG. 9 (A), the first and second inner leads 34-1 and 36-1 must be formed as follows. They may be formed so as to be located symmetrically to each other via a straight line 200 orthogonal to the straight line 100. In this way, by crushing the winding portion 40 from a direction orthogonal to the straight line 100, the leads are positioned at equal intervals and on a straight line as in the case shown in FIG. 5 or FIG. A terminal-type noise filter can be formed.

Next, the noise reduction effect of the four-terminal noise filter of the present invention will be described in detail.

a) Experiment on Common Mode Noise FIG. 10 shows noise that enters through a power supply line when a DC voltage is supplied from a DC power supply 50 to a load 52 such as an electronic circuit.

The noise that enters the load 52 via the power supply line is asymmetric noise generated from the positive power supply line to the ground side or from the negative power supply line to the ground side, and most of the common mode noise belongs to this.

To eliminate such common mode noise,
As shown in FIG. 11, assuming that a four-terminal noise filter 200 according to the present invention was connected between the DC power supply 50 and the IC load 52, an experiment was conducted on what kind of noise reduction effect was obtained. .

The noise filter 200 used for this experiment is the first
It is of the type shown in FIG.
2 is made of aluminum foil having a total length of 90 cm, a width of 6 mm, and a thickness of 15 μm. As the dielectric sheets 32-1 and 32-2, a mylar tape having a width of 8 mm and a thickness of 9 μm is used.
In order to create a filter, a winding shaft 38 having a radius r = 1 mm is used.
Was used.

First, an electrostatic damage test was performed using a circuit as shown in FIG.

At this time, an electrostatic simulator with an output voltage of 1 KV was used as the DC power supply 50. As the load 52, two 50Ω resistors connected in series were used.

At this time, when the filter 200 of the present invention was not used, a voltage of 112.0 V was generated at both ends of the 50Ω resistor.
It was confirmed that by using the four-terminal noise filter 200 of the present invention, the voltage across the 50Ω resistor was reduced to 20.8V.

Next, a switching power supply output noise test was performed using the circuit shown in FIG.

In this test, a 300 Ω resistor was used as the load 52.

At this time, the DC power supply 50 and the resistor 52 are used without using the filter 200.
When と was directly connected, noise of 290 mV _pp was detected at both ends of the resistor 52, but it was confirmed that this noise was reduced to 80 mV _pp by connecting the filter 200.

Further, the four-terminal noise filter 200 of the present invention effectively attenuates the common mode noise in this way. For this reason, noise generated by ringing is also attenuated in a very short time, so that the influence of ringing can be almost ignored.

As described above, the four-terminal noise filter of the present invention can generate various types of common mode noise, for example, electrostatic noise,
It has been confirmed that the device has an excellent noise attenuation characteristic that various noises such as switching surge can be reliably removed without causing ringing.

This is because the four-terminal type noise filter of the present invention functions as a distributed constant type noise filter as shown in FIG. 3, and its L component functions effectively to effectively reduce such various common mode noises. It is presumed to be removed.

Next, the following experiment was conducted to compare the effect of the four-terminal noise filter of the present invention with the effect of the conventional noise filter.

In this experiment, two types of filters, TH3820B and TH5130B, were used as the four-terminal noise filter according to the present invention.

Here, the TH3820B type four-terminal noise filter uses aluminum foil having a total length of 62 cm, a width of 6 mm and a thickness of 15 μm as the conductive strips 30-1 and 30-2.
For 32-1 and 32-2, a minor tape having a width of 8 mm and a thickness of 9 μm is used, and a radius r =
A 1.0 mm winding shaft 38 was used.

The TH5130B four-terminal noise filter has a total length of 90 cm, a width of 6 mm, and a thickness of 1 as the conductive strips 30-1 and 30-2.
Use 5μm aluminum foil and dielectric band sheet 32
A polyester tape having a width of 8 mm and a thickness of 9 μm is used as -1,32-2, and a radius r is used to form a filter.
= 1.0 mm reel 38 was used.

As a conventional four-terminal noise filter, a toroidal coil type filter shown in FIG. 15A was used.
The core used in this filter is formed in a ring shape having an inner diameter of 6 mm, an outer diameter of 14 mm and a width of 3 mm as shown in FIG. 15 (b). A coil having a wire diameter φ = 0.32 is wound around the core 13 times in total.

FIG. 15 (c) shows an equivalent circuit diagram of the toroidal coil type filter.

FIG. 16 shows the electrical characteristics of two types of four-terminal noise filters, TH3820B and TH5130B, and the conventional toroidal coil type filter shown in FIG. 15 (a). Here, both values of L are 36-1, 34-1.
Was measured at the terminal. The measurement frequency at this time is f = 1kHz
It is.

Using the filters thus formed, the seventeenth
The switching power supply output noise, which is a kind of common mode noise, was measured using the circuit shown in the figure. In this experiment, a 250 ohm resistor was used as the load 52 and a 24 volt power supply was used as the DC power supply 50.

FIG. 18 shows measured waveform data of an experiment performed using this circuit. In FIG. 18, the horizontal axis represents time, and the vertical axis represents measured voltage.

FIG. 7A shows data when a measurement point is short-circuited, and FIG. 7B shows measurement data when a conventional toroidal coil filter is used as a noise filter.
FIG. 13C shows measurement data of a TH3820B type noise filter according to the present invention, and FIG. 14D shows data of a TH5130B noise filter according to the present invention.

FIG. 19 shows the measured data in numerical values,
Vp-p is the peak-to-peak value of the common mode noise voltage,
t represents the time until the noise converges to O volts.

As is clear from the measurement data, it was confirmed that the convergence time of the common mode noise of the four-terminal noise filter according to the present invention was extremely shorter than that of the conventional toroidal coil filter.

Further, in the four-terminal noise filter of the present invention, since the convergence time of the common mode noise is extremely short, even if ringing occurs, the noise converges in a very short time. There is an effect that can be.

b) Experiment on Normal Mode Noise Next, using the circuit shown in FIG. 20, a test was conducted on the effect of reducing the normal mode noise. In this test, an experiment was conducted on how a ripple component can be reduced in a DC line for a D-RAM.

FIG. 21 shows the measured data at this time, and FIG.
(B) is data when a toroidal coil type filter is used, FIG. (C) is data when a TH3820B noise filter of the present invention is used, and FIG. d) is data when using the TH5130B noise filter of the present invention.

 FIG. 22 shows the measured data by numerical values.

As is clear from the measurement data, when the conventional toroidal coil type filter is used, the ripple voltage increases rather than when no filter is used. On the other hand, it was confirmed that the ripple voltage can be greatly reduced by using the four-terminal noise filter of the present invention.

Thus, it has been confirmed that the four-terminal noise filter of the present invention has an excellent noise attenuation effect that various types of normal mode noise can be reliably removed. This is because the four-terminal type noise filter of the present invention functions as a distributed constant type noise filter as shown in FIG. 3, and the C component of the four-terminal type noise filter effectively functions to remove normal mode noise. It is presumed.

Further, the present invention is not limited to the above embodiment, and various modifications can be made within the scope of the present invention.

For example, a four-terminal noise filter of the present invention, when it is desired to increase the inductance of each coil L ₁ and L _2, or use core magnetic body in the center of the winding portion 40, and as the strip conductors A magnetic conductor may be used.

In the above embodiment, the two strip-shaped conductors 30-
Although a case where a laminate is formed using 1, 30-2 and two dielectric sheets 32-1 and 32-2 has been described as an example, the present invention is not limited to this, and for example, a strip-shaped conductor, a dielectric Three or more sheets may be provided, and two of the strip-shaped conductors may be provided with leads.

Further, in the above embodiment, the case where the four-terminal type noise filter of the present invention is pressed and formed into an elliptical shape is described as an example, but the present invention is not limited to this, and the noise filter may be formed in a circular shape. It is possible.

In this case, in consideration of the diameter of the winding shaft, the total length of the strip-shaped conductor, and the like, the mounting position may be calculated in advance so that the leads are aligned in a straight line.

This makes it possible to form a circular four-terminal noise filter in which the leads are arranged substantially in a straight line. By using this noise filter, as described above, common mode noise and normal mode noise can be reliably removed.

Further, in the above-described embodiment, the case where the four-terminal noise filter of the present invention is used as a noise filter for a DC line has been described as an example. .

[Effects of the Invention] As described above, according to the present invention, a small and lightweight four-terminal noise filter having excellent attenuation characteristics can be obtained, and both common mode noise and normal mode noise can be reliably obtained. Can be removed. In particular, the four-terminal noise filter of the present invention can reliably remove various noises entering the electronic circuit and various noises generated from inside the electronic circuit without generating ringing or the like.

Further, according to the present invention, since the respective leads can be arranged at a constant interval on a straight line including the center of the winding shaft, a four-terminal type having substantially uniform and good attenuation characteristics and excellent mass productivity. A noise filter is obtained. Therefore, there is an effect that problems that must be considered in manufacturing such a distributed constant type noise filter, for example, problems such as uneven characteristics and low yield can be solved.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a preferred embodiment of a four-terminal noise filter according to the present invention, FIG. 2 is an explanatory view of a laminate used for the noise filter shown in FIG. 1, and FIG. 4 is an explanatory diagram of a modified example of the noise filter shown in FIG. 1, and FIGS. 5 to 9 are second preferred embodiments of the four-terminal noise filter according to the present invention. FIG. 10 is an explanatory diagram of common mode noise that enters a load from a DC power supply via a power supply line. FIG. 11 is an explanatory diagram of a case where the four-terminal noise filter of the present invention is connected to the power supply line. 12 and 13 are circuit diagrams used for a noise removal experiment of the noise filter of the present invention, FIG. 14 is an explanatory diagram of a lumped constant type four-terminal noise filter conventionally used, and FIG. It is an explanatory view of a toroidal coil type filter, FIG. 1 (a) is an external view of the filter, FIG. 2 (b) is an explanatory view of a core used in the filter, FIG. 1 (c) is an equivalent circuit diagram of the filter, and FIG. Electrical characteristic diagram of the noise filter and the conventional filter shown in FIG. 15, FIG. 17 is a circuit diagram used for confirming the effect of reducing the output noise (common mode noise) of the switching power supply, and FIG. 18 is a circuit shown in FIG. FIG. 19 is an explanatory view of experimental data performed using the circuit of FIG. 17, and FIG. 20 is a ripple (normal mode noise) reduction effect in a DC line for a D-RAM. Circuit diagram used for confirmation experiment, FIG. 21 is a waveform diagram of an experiment performed using the circuit shown in FIG. 20, and FIG. 22 is an explanatory diagram of experimental data performed using the circuit shown in FIG. It is. 30-1, 30-2 ... strip-shaped conductor 32-1, 32-2 ... dielectric sheet 34-1 ... first inner lead 34-2 ... first outer lead 36-1 ... second inner Lead 36-2: second outer lead 38: winding shaft 40: winding part

Claims (4)

(57) [Claims] 1. A band-shaped conductor having input / output first inner leads and first outer leads connected near both ends, and input / output second inner leads and second outer leads connected near both ends. And a belt-shaped conductor are wound in a tubular shape via a dielectric sheet, the first inner lead and the second inner lead are used as one input / output terminal, and the first outer lead and the second outer lead are used as the other input and output terminals. An air-core type four-terminal noise filter serving as an output terminal, wherein the first outer lead and the second outer lead are shifted by about 1/2 turn, and the first inner lead and the second inner lead are In a state shifted by about 1/2 turn, the wound laminate is pressed flatly from a direction orthogonal to a straight line connecting the outer leads, and the leads are formed so as to be substantially aligned. Characteristic air-core type 4 terminals Noise filter. 2. A band-shaped conductor having input / output first inner leads and first outer leads connected near both ends, and input / output second inner leads and second outer leads connected near both ends. And a belt-shaped conductor are wound in a tubular shape via a dielectric sheet, the first inner lead and the second inner lead are used as one input / output terminal, and the first outer lead and the second outer lead are used as the other input and output terminals. An air-core type four-terminal noise filter serving as an output terminal, wherein the first outer lead and the second outer lead are shifted by about 1/2 turn, and the first inner lead and the second inner lead are Are arranged so as to be located symmetrically to each other with a line orthogonal to a line connecting the first and second outer leads as a line symmetry axis, and the rolled-up laminate is wound from a direction orthogonal to a straight line connecting the outer leads. Push your body flat And, the air-core type four-terminal noise filter, characterized in that each of said leads is formed so as to substantially align in a straight line. 3. A multilayer body is formed by superposing a plurality of strip-shaped conductors via a dielectric sheet, and a first inner lead and a second inner lead for input and output are provided near the inner end of each strip-shaped conductor. A first step of connecting, while winding the laminate around a rotary winding axis a plurality of times, and near the outer end of each strip-shaped conductor so as to be located substantially in a straight line through the center of the winding axis, for input and output. A second step of connecting the first outer lead and the second outer lead; removing a rotary winding shaft from the wound laminate, pressing the laminate from a direction orthogonal to a straight line connecting the outer leads, and forming each lead. And a third step in which the first and second inner leads are positioned substantially in a straight line via the center of the winding axis. Near the inner end of each strip conductor 4 production method of the terminal type noise filter which is characterized in that. 4. A stacked body is formed by superposing a plurality of strip-shaped conductors via a dielectric sheet, and a first inner lead and a second inner lead for input and output are provided near the inner end of each strip-shaped conductor. A first step of connecting, while winding the laminate around a rotary winding axis a plurality of times, and near the outer end of each strip-shaped conductor so as to be located substantially in a straight line through the center of the winding axis, for input and output. A second step of connecting the first outer lead and the second outer lead; removing a rotary winding shaft from the wound laminate, pressing the laminate from a direction orthogonal to a straight line connecting the outer leads, and forming each lead. A third step of forming the first and second inner leads into the first and second inner leads in the first step.
A method for manufacturing a four-terminal type noise filter, wherein a line orthogonal to a line connecting outer leads is arranged line-symmetrically with respect to a line symmetry axis.