JPH0536538A - Line filter transformer - Google Patents

Abstract

(57) [Summary] (Correction) [Construction] This is a coil 2 in which rectangular wires are laminated and wound in the axial direction on the same circumference. [Effect] Since the distributed capacitance of the line filter transformer can be reduced, a noise prevention filter that can prevent noise up to a high frequency band can be configured, and since the DC resistance of the line filter transformer is reduced, a noise prevention filter with low power loss can be configured. it can.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a line filter transformer suitable for use as a noise prevention filter inserted in a power supply circuit.

[0002]

2. Description of the Related Art A conventional noise prevention filter inserted in a power supply circuit removes common mode noise and is required to remove noise from low frequencies to high frequencies. There is. For this reason, a line filter transformer that can be used in a wide band from low frequency to high frequency is required as a line filter transformer used for a noise prevention filter inserted in the power supply circuit. Capacitance became a problem, and it was difficult to obtain a line filter transformer with a wide band up to high frequencies.

Conventionally, it has been proposed to use an integral type completely closed magnetic circuit core as the line filter transformer in order to obtain the same inductance value even if the number of windings is reduced and the distributed capacitance is reduced. There is an inconvenience that it is difficult to form a winding on the core of the integral type complete closed magnetic circuit.

Further, it is possible to make a single winding to prevent an increase in distributed capacitance due to the multi-layer winding, but it is necessary to wind on a core of a limited size and a thin wire must be used as the winding. However, there was a problem that the electric resistance increased.

It has also been proposed to use this winding as a split winding to reduce the distributed capacitance. However, the split winding bobbin is expensive and the winding space is taken by the split collar of the bobbin, which is large in size. There was an inconvenience to become. The present invention has been made in view of the above problems, and an object thereof is to propose a line filter transformer in which the above inconvenience is improved.

[0006]

The line filter transformer of the present invention uses a coil 2 in which a rectangular wire 2a is axially laminated and wound on the same circumference as shown in FIGS. 1 and 2, for example. is there.

[0007]

According to the present invention, since the coil 2 in which the rectangular wire (ribbon wire) 2a is axially laminated and wound on the same circumference is used, the distributed capacitance is the distributed capacitance between the windings in series. Since it is connected and the distributed capacitance of this line filter transformer is small, it is possible to construct a filter up to the high frequency band, and since a rectangular wire is used, the DC resistance of this line filter transformer is small, and the efficiency with low loss is small. You can get a good filter.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the line filter transformer of the present invention will be described below with reference to the drawings. In this example, as shown in FIG. 1, the leg portions 1a and 1b of the U-shaped ferrite core 1 forming a closed magnetic circuit are respectively laminated with the rectangular wire 2a as shown in FIG. 2 in the axial direction on the same circumference. The wound coil 2 is arranged. Specifically, the coil 2 has a width a of 1.
A rectangular wire (ribbon wire) having a thickness of 45 mm and a thickness of 122 μm is axially laminated on the same circumference with an inner diameter b of 5 mm and wound for, for example, 140 turns, and its end is led out as a terminal. U forming a magnetic path in the inner diameter of the coil 2
The legs 1a and 1b of the type ferrite core 1 are inserted.

In this example, since the coil 2 in which the rectangular wire is axially laminated and wound on the same circumference as described above is used, the distributed capacitance of the coil 2 is such that the distributed capacitance between the windings is connected in series. Since the distributed capacitance of the coil 2 becomes small, the distributed capacitance of the line filter transformer becomes small, and when the line filter transformer is used to construct a noise prevention filter to be inserted in the power supply circuit, a high frequency band is generated. A filter that can prevent up to noise can be configured.

The rectangular wire 2 of the coil 2 used in this example
Since a has a small DC resistance, when this noise prevention filter is inserted in the power supply circuit, the power loss is reduced accordingly, and there is an advantage that an efficient noise prevention filter can be constructed.

Further, according to this embodiment, since the bobbin for dividing the winding is not used, there is an advantage that it can be manufactured in such a small size and at a low cost. Note that the present invention is not limited to the above-described embodiments, and needless to say, various other configurations can be adopted without departing from the gist of the present invention.

[0012]

According to the present invention, since the distributed capacitance of the line filter transformer can be made small, there is an advantage that a noise prevention filter capable of preventing noise up to a high frequency band can be constructed, and the direct current of the line filter transformer can be reduced. Since the resistance is reduced, there is an advantage that the power loss due to the line filter transformer is reduced when the line filter transformer is used in the power supply circuit.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a line filter transformer of the present invention.

FIG. 2 is a perspective view showing an example of a coil used in the line filter transformer of the present invention.

[Explanation of symbols]

 1 U-type ferrite core 1a, 1b Leg 2 Coil 2a Flat wire

Claims (1)

Claim: What is claimed is: 1. A line filter transformer, comprising: a coil in which a rectangular wire is axially laminated and wound on the same circumference.