JPS6354706A - Choke coil and transformer - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Summary] A coil or transformer is constructed by forming a spiral conductive pattern directly on a printed circuit board.

[Industrial application field]

The present invention relates to a choke coil for obtaining inductance and a power transformer for changing voltage, and relates to a configuration in which a spiral pattern formed on a printed circuit board and a magnetic core of a core material are combined.

[Conventional technology]

Conventionally, a choke coil is a combination of a wire wound around a bobbin and a magnetic core made of a core material, and is generally used for the purpose of obtaining inductance for blocking high frequencies.

Further, a power transformer has a magnetic core made of a core material, with a primary winding on one side and a secondary winding on the other side.

[Problem that the invention seeks to solve]

In parts that handle high frequencies, such as the secondary side of a transformer in a high-frequency switching power supply, it has been desired to make the coil or transformer thinner because the number of turns of the S wire and the cross-sectional area of the core material can be reduced. When using a winding made of wire wrapped around a bobbin and mounting it on a printed circuit board, there is a problem that the height of the coil or transformer is high and it requires space, and the process of forming the winding There were problems such as variations in the results. Therefore, the present invention provides a coil and a transformer that do not require space and do not cause variations in accuracy.

[Means for solving problems]

According to the present invention, a choke coil is provided in which a conductive pattern is formed in a spiral shape on a printed circuit board, and a magnetic core of a core material passes through an inner opening and two outer openings of the spiral.

Further, according to the present invention, a conductive pattern is spirally formed on a printed circuit board to form a primary coil, a conductive pattern is spirally formed on a surface or layer different from the primary coil to form a secondary coil, and both A transformer is provided which combines a magnetic core of core material passing through an inner opening and two outer openings of a coil volute.

[For production]

Since a spiral pattern is formed directly on the printed circuit board,
Does not require a bobbin like traditional coils or transformers,
Further, there is no need to wind the wire around the bobbin. Further, since only a portion of the magnetic core protrudes above and below the printed circuit board, the required space is extremely small.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows a high frequency choke coil 10 formed on a printed board 1, and numerals 2, 3, and 4 are other components mounted on the same printed board 1. A conductive pattern 12 is formed in a spiral shape on the front surface 1a of the printed board 1, and the end thereof is connected to a conductive pattern or a jumper 14 on the back surface 1b via a through hole 13, and straddles the conductive pattern 12 on the front surface 1a. The spiral conductive pattern 12 is formed by a normal pattern forming method such as a photoetching method, and is formed on the surface 1a.
The back surface 1b is coated with an epoxy resin or the like and insulated. One rectangular opening 1 inside the spiral conductive pattern 12
5 and two rectangular openings 16 and 17 are provided on the outside, and a magnetic core 18 is installed so as to pass through these openings. As shown in the figure, the magnetic core 18 is a combination of a ■-shaped piece 19 and an E-shaped piece 20, each of which is constructed by laminating a large number of thin core materials using a well-known method.

2 and 3 show a transformer 30 for a high-frequency switching power supply formed on a printed board 1. On the surface 1a of the printed board 1, a conductive pattern is formed in a spiral shape as a 32-month coil in the same manner as described above. The end thereof straddles the conductive pattern 32 on the front surface 1a with a conductive pattern or jumper 34 on the back surface 1b via a through hole 33. On the other hand, a conductive pattern 35 is formed in a spiral shape as a secondary coil on the back surface 1b, and the end thereof is connected to a conductive pattern or a jumper 37 on the surface 1a via a through hole 36, and straddles the 8-conductor pattern 35 on the back surface 1b.

There is one rectangular opening 38 on the inside of the primary coil 32 and the secondary coil 35 and two rectangular openings 39, 40 on the outside, and the magnetic core 18 is inserted through these openings as before.

In the above embodiments, a multilayer printed board may be used as the printed board, and a conductive pattern, a primary coil, or a secondary coil may be formed in the intermediate layer. The two pieces forming the magnetic core 18 include the combination of the ■-shaped piece 19 and the E-shaped piece 20 as described above, as well as the L-shaped piece 21 as shown in FIGS. Various combinations are possible, such as a combination of the F-shaped piece 22 and a combination of the U-shaped piece 23 and the T-shaped piece 24.

〔Effect of the invention〕

According to the present invention, since the windings of the coil or transformer are formed by the pattern of the printed board, the height dimension is only the magnetic core of the core material, and the thickness can be reduced. Further, since no bobbin is required and there is no winding work, the number of parts is small and the work is easy, and the patterning reduces variations in accuracy.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a choke coil according to the present invention;
FIG. 2 is a perspective view showing a transformer for a high frequency switching power supply (magnetic core omitted) according to the present invention, FIG. 3 is a sectional view of the transformer, and FIGS. 4 and 5 are examples of the magnetic core of the core material. 1... Printed board, 10... Coil, 12...
...Conductive pattern, 18...Magnetic core, 15, 16
, 17... Opening, 30... Transformer, 32
...Flame coil, 35...Secondary coil, 38
, 39, 40...opening.

Claims (2)

[Claims] 1. A conductive pattern (12) is formed in a spiral shape on a printed circuit board (1), and an opening (15) inside the spiral and two openings outside the spiral are formed.
The magnetic core (18) of the core material passes through the two openings (16, 17).
) choke coil. 2. A conductive pattern is spirally formed on a printed circuit board (1) to form a primary coil (32), and a conductive pattern is spirally formed on a surface or layer different from the primary coil to form a secondary coil (32).
35) and a magnetic core (18) of a core material passing through an inner opening (38) and two outer openings (39, 40) of the spirals of both coils.