JPH02196406A - Laminated transformer - Google Patents

Abstract

PURPOSE:To obtain at low cost by a simple process a transformer with no decrease in the self resonance frequency and is suitable to high frequency use, by alternately superposing and laminating a plurality of magnetic substance sheets formed by using insulative paste composed of ferromagnetic substance and a plurality of conductors printed so as to make both ends protrude on the peripheral side of the sheet. CONSTITUTION:A raw lamination body 11 is constituted by alternately superposing the following; a plurality of magnetic substance sheets 1 laminated by using insulative paste composed of ferromagnetic substance, and a plurality of conductors 2 whose central parts are rectilinear types or zigzag types printed and formed by using conductor, so as to make both ends protrude on the peripheral side of the sheet. On the peripheral surface of the raw lamination body 11, electrode terminals 3, 3', 4, 4', 5, 5' composed of conducting material connected with respective both ends of the above conductors 2 are arranged. The above magnetic substance sheets 1 constitutes a magnetic core, and the above conductors 2 constitute a primary winding and a secondary winding. For example, the above conductor 2 is printed and formed by using high melting point metal paste composed of Ag or Ag alloy. After the row lamination body 11 is sintered in a body at a specified temperature, film type electrode terminals 3, 3', 4, 4', 5, 5' are plated on the peripheral surface.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a laminated transformer that can be surface mounted on a printed wiring board in a high frequency electronic circuit or the like.

[Conventional technology]

An example of a conventional laminated transformer is shown in FIG.

As shown in Figure 9-1, Ag or A
The entire L-shaped conductor 2a is printed using a conductor paste made of g alloy, with the starting end a1 protruding from one edge, and on top of this, the final end a2 of the conductor 2a is exposed as shown in Figure 9-2, and approximately half of the entire length is printed. Cover and laminate with the second cerebral body sheet 1-2.

Further, as shown in Fig. 9-6, an L-shaped conductor 2b is printed on this with the starting end b1 protruding to the other edge, and the terminal end b2 is exposed as shown in Fig. 9-4. The third magnetic sheet 1-6 is covered and laminated with a third magnetic sheet 1-6, which is partially cut out in approximately half of the whole so as to expose a portion of the magnetic sheet and the starting end b1. Further, as shown in Fig. 9-5, the terminal end b2 and the starting end bl are connected and a U-shaped third conductor 2b' is laminated, and as shown in Fig. 9-6, a fourth magnetic body in half of the whole is laminated. Cover and laminate with sheets 1-4. Next, as shown in FIG. 9-7, the starting end a1 is connected to the exposed terminal end a2 of the conductor 2a, the terminal end a2 is projected to the edge of the magnetic material, and a spiral fourth conductor 2a' is laminated.

Furthermore, as shown in FIG. 9-8, a cutout window 10 is provided to expose the terminal end b2, and the whole is covered with a fifth magnetic sheet 1-5, and the starting end b1 is connected to the terminal end b2 as shown in FIG. 9-9. Connect and stack the fifth conductor 2b'' with the terminal end b2 protruding from the edge, and finally, as shown in Figs.
-6 to form a raw laminate 1-1 similar to that shown in FIG. Starting end a1e terminal end a2 of conductor 2a and starting end b1 of conductor 2b exposed on opposing edge surfaces of green laminate 11
and the terminal end b2 are stained with a conductive material, respectively.
By setting 3', 4, and 4', a surface-mounted laminated transformer that can be mounted on a surface as shown in FIG. 3 is formed.

This type of laminated transformer has an equivalent circuit similar to that shown in FIG.
This is a transformer in which the electrode terminals 4 and 4° are used as terminals 7 and 71, the conductor 2b is used as a winding, and the magnetic sheet 1 is used as a magnetic core.

[Problem that the invention seeks to solve]

However, in conventional laminated transformers.

Multiple circumferential 7 conductors have electrode terminals 3,3" and 4°4" for each layer.
Since the distances are close, stray capacitance increases and the self-resonant frequency decreases significantly, making it unsuitable for use in high frequency ranges. In addition, since the distance between the conductors 2 in each magnetic sheet 1 cannot be made sufficiently low, the leakage inductance component increases due to the decrease in magnetic resistance between the conductors in the magnetic path due to the current flowing through the conductors 2, resulting in conversion as a transformer. The drawback is that efficiency is greatly reduced. Furthermore, since the magnetic material 1 and the conductor 2 are repeatedly printed alternately, a drying step is required for each step, which has the disadvantage of being expensive.

[Means for solving problems]

The present invention eliminates such drawbacks of the conventional method and provides a plurality of magnetic sheets 1 formed of an insulating paste made of an insulating material having ferromagnetic insulation properties.

Between each, a metal paste is printed and formed with both ends protruding from the edge of the magnetic sheet 1.

Electrode terminals 3, 3°, 4 made of a conductive material are provided on the edge surface of the green laminate 11, in which a plurality of conductors 2 whose center portions are straight or meandering are alternately superimposed, and are made of a conductive material at both ends of each of the conductors 2.
, 4' are provided, and each conductor 2 is connected to the primary winding or 2
This is a laminated transformer in which the next winding is the magnetic core and the magnetic sheet 1 is the magnetic core.

[For production]

The laminated magnetic sheets 1 serve as a magnetic core.

The conductor 2 sandwiched and overlapped between the electrode terminals 3, 3', 4, 4' and the respective magnetic sheets 1 connected thereto has a plurality of conductors 2 between each end as a winding wire. With a transformer having a primary winding and a secondary winding, the leakage inductance component when current is passed through the conductor 2 is reduced.

〔Example〕

Embodiments of the laminated transformer of the present invention will be described with reference to the drawings.

As shown in FIGS. 1, 2, 6, and 4.

A slightly thick insulating magnetic paste made by mixing and kneading raw insulating ferrite powder, a binding resin, and an anatomical material (a high melting point metal paste made of Ag or Ag alloy, etc. , a first conductor 2a with a straight center and both ends bent in the same direction near opposite edges to protrude is printed.Then, a second conductor 2a is printed in the same direction near the sides of the conductor 2a but in the opposite direction to the lower conductor 2a. Furthermore, a second magnetic sheet 1-3 made of insulating magnetic paste is superimposed and laminated on the conductor 2b, and the first and second magnetic sheets are pressed as shown in FIG. A raw laminate 11 in which both end surfaces of the conductors 2 a l 2 b are exposed to opposing edge surfaces to form a closed magnetic path.
is formed.

After integrally sintering the raw laminate at a predetermined temperature, the first and second conductors 2a are exposed on both edge surfaces as shown in FIG.
It is connected to both ends of 2b and plated with a membrane electrode terminal made of a conductive material on each edge surface, and can be mounted on a substrate surface such as a printed wiring board. A transformer is obtained.

Therefore, as shown in Fig. 4, this type of laminated transformer uses the magnetic body 1 as the magnetic core, and the primary winding with the terminals 6, 6'' between the electrode terminals 6, 3'' and the electrode terminals 4, 4'. terminal 7
, 7″, and the transformer is equivalent to the secondary winding.

Further, a second embodiment according to the present invention is shown in FIGS. 5, 6, and 7.
As shown in FIG.

As shown in FIG. 5, a first conductor 2a is printed on the magnetic sheet 1-1, the center of which is bent in a meandering manner, and the two ends of which are bent in the same direction near opposing edges and projected. On top of this, a second magnetic material sheet (1-2) is superimposed and laminated, and on top of this is a second conductor (2bi) whose center is bent in the same meandering shape as the lower layer and whose two ends protrude perpendicularly to the center of the opposing edges. Print. Furthermore, a third magnetic material sheet 1-6 is superimposed and laminated on top of this, and on top of this, the center is bent in the same meandering shape as the lower layer, and both ends are near the opposing edges (in the same direction and opposite to the first conductor 2a). Print the entire third conductor 2C that is bent and protruded.Finally, print the fourth conductor 2C.
1-4'e superimposed layers, and the first magnetic material sheet as shown in FIG. second and sixth conductors 2a, 2b;

A green laminate 11 is formed in which both end faces of each of the 2C are exposed to the opposing edge faces to form a closed magnetic path.

This raw laminate 11 is integrally sintered at a predetermined temperature.

1°5.5' exposed on both edge surfaces as shown in Figure 7
A three-wound laminated transformer that can be plated and mounted on the substrate surface is obtained.

Therefore, this type of laminated transformer uses the magnetic sheet 1 as the magnetic core as shown in FIG.

Electrode terminals 6 and 3' are connected to terminals 6 and 6+, electrode terminals 4 and 4'' are connected to terminals 7 and 7'', and electrode terminals 5 and 5'' are connected to terminals 8 and 8'.
A laminated transformer equivalent to three windings corresponding to is obtained.

〔Effect of the invention〕

As described above, according to the present invention, both ends of the conductor 2, that is, the starting end and the ending end, are located on opposing edge surfaces, and the conductor 2 between them is not overlapped, so there is little stray capacitance, and the self-resonant frequency is significantly lowered. to be suppressed. Also, the first and second conductors 2a
, 2b, which acts as a leakage inductance component of the magnetic path generated by the current flowing through the conductors 2a and 2b.Since the magnetic path components between the conductors 2a and 2b are overlapped in the stacking direction via the extremely thin magnetic sheet 1-2, the magnetic path between the conductors 2 is The dielectric strength is sufficient, and the mutual magnetic resistance value is sufficiently high compared to the main magnetic resistance value of the outer magnetic material, and the self-resonant frequency is not lowered and a transformer suitable for high frequencies can be created in a simple process. Obtained cheaply.

Figure 2 is an external perspective view of the raw laminate assembled from Figure 1, Figure 3 is an external perspective view of each conductor in Figure 2 with electrode terminals provided, and Figure 4 is the equivalent circuit in Figure 3. 5 is an external perspective view of a green laminate according to a second embodiment of the present invention, and FIG. 6 is an external perspective view of a green laminate assembled from the structure shown in FIG. 5.

Fig. 7 is an external perspective view of the conductors shown in Fig. 6 with electrode terminals provided respectively, Fig. 8 is an equivalent circuit diagram of Fig. 7, and Fig. 9 is an exploded plan view showing the steps of the structure of a conventional laminated transformer. It is a diagram.

In addition 1: @ conductor sheet, 2.2a, 2b, 2c: conductor.

3, 3', 4, 4', 5, 5': electrode terminal, 6.6', 7°7', 8.8': terminal, 10: notch, window, 11: green laminate.

[Brief explanation of the drawing]

Figure 1 is Figure 5 of the laminated transformer according to the present invention. Figure 2 Figure 3 Figure 4 ('-/-/f/)

Claims (1)

[Claims] 1. A plurality of magnetic sheets 1 laminated with an insulating paste made of a ferromagnetic insulating material, and a plurality of conductors having both ends protruding from the edges and printed with a conductor, the central portion of which is linear or meandering. Electrode terminals 3, 3', 4, 4 made of a conductive material are connected to both ends of each of the conductors 2 on the edge surface of the raw laminate 11 in which the conductors 2 and 2 are alternately superimposed.
', 5, 5', the magnetic sheet 1 is used as a magnetic core, and the conductor 2 is used as a primary winding and a secondary winding.