JP2000060125A - Power unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power unit which can take a sure insulating structure of the primary circuit and the secondary circuit of a transformer and whose circuits can be downsized easily by short-circuiting the insulating distance. SOLUTION: For this power unit, a converter transformer 100 and a printed board 200 are jointed with each other with a pin 140 projected from a transbobbin 120, and they are housed in an insulating case 300. At the printed board 200, a slit 600 in a shape dividing a primary circuit 210 and a secondary circuit 220. Moreover, the fused liquid of insulating filler 400 is injected into the insulating case 300, so as to fill the interiors of the insulating case 300 and the slit 600. Then, an insulating structure of mold part, where the primary circuit 200 and the secondary circuit 220 are surrounded with insulating filler material 400, is formed by the insulating filler solidifying.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a power supply device including a transformer.

[0002]

2. Description of the Related Art As a power supply device of this type, for example, AC power obtained from a DC voltage source via a switching circuit is supplied to a primary winding of a converter transformer, and is obtained from a secondary winding of the converter transformer. There is known a resonance type switching power supply which rectifies AC power supplied by a rectifier circuit and further smoothes the AC power by a smoothing circuit. FIG. 3 is a schematic plan view showing a circuit component arrangement in a conventional switching power supply. As shown in the figure, this switching power supply has a converter transformer 12 arranged at the center on a printed circuit board 10 and a primary circuit 14 and a secondary circuit 16 distributed on both sides of the converter transformer 12. In addition, the insulating property is ensured by providing an interval of 6 mm between the two.

That is, in such a configuration in which the primary circuit 14 and the secondary circuit 16 are separated by using the transformer 12, in order to comply with safety standards in various countries around the world, the primary circuits 14 and 2 are required. Whether the insulation distance between the wiring patterns of the secondary circuit 16 and the parts that cannot be insulated is 6 mm or more,
It is necessary to have an insulation structure to meet the withstand voltage test separately regulated. For this reason, in a conventional switching power supply, 6 m
An insulation distance of m is used.

[0004]

However, in the conventional switching power supply, the distance between the primary side and the secondary side is 6 mm.
In order to reduce the size of the power supply circuit, it is difficult to take such an insulating distance.

Accordingly, an object of the present invention is to provide a reliable insulation structure between a primary circuit and a secondary circuit of a transformer,
An object of the present invention is to provide a power supply device capable of easily reducing the size of a circuit by shortening an insulation distance.

[0006]

In order to achieve the above object, the present invention provides a power supply apparatus for supplying a power supply voltage input from a primary side circuit to a secondary side circuit via a transformer. A printed circuit board on which a secondary circuit is mounted,
A support member for fixing the transformer to the printed circuit board; an insulating case for housing the printed circuit board and the transformer; formed at a position formed on the printed circuit board to divide the primary circuit and the secondary circuit. And an insulating filler filled in the insulating case and the slit.

In the power supply device of the present invention as described above,
The printed circuit board on which the transformer and its primary and secondary circuits are mounted is integrally fixed via a support member and housed in an insulating case. Then, the primary circuit and the secondary circuit mounted on the printed circuit board are surrounded by the insulating filler and are reliably insulated by the insulating filler filled in the insulating case. Further, by filling the slit formed in the printed board with the insulating filler, the wiring pattern of the printed board is also reliably separated on the primary side and the secondary side, and a reliable insulating structure can be obtained. .

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a power supply according to the present invention will be described below. FIG. 1 is a diagram showing a structure of a switching power supply as one embodiment of the present invention.
1A is a schematic side sectional view, and FIG. 1B is a schematic bottom view of a printed circuit board. The configuration shown in FIG. 1 is, for example, an S for TV.
FIG. 3 shows the appearance of a converter section of a switching power supply used for a TBY power supply,
, A printed board 200, an insulating case 300, an insulating filler 400, and a mounting board 500.

The converter transformer 100 includes a core 110
A transformer bobbin 120 is disposed on the outer periphery of the transformer bobbin, and primary and secondary windings 130 are wound around the transformer bobbin 120. The converter transformer 100 has an insulating structure in which an interlayer insulating tape 132 is wound so that the primary and secondary windings do not contact each other by the transformer bobbin 120. Also, the trans bobbin 120
A plurality of pins (supporting members) 140 are protruded downward from the lower surface. Each of the pins 140 is soldered to a through hole (corresponding to a copper foil portion) 202 of the printed circuit board 200, and extends to the mount substrate 500 side to extend through the through hole (copper (Corresponding to a foil portion) 502 by soldering. Note that instead of soldering the pins 140 through the through holes 202 and 502, the pins 140 may be soldered and joined to a copper foil portion formed on the printed circuit board 200 and the mount board 500. Each pin 140 connects the primary winding to the primary circuit on the printed circuit board 200, connects the secondary winding to the secondary circuit on the printed circuit board 200, and further connects the printed circuit board. The circuit on 200 and the circuit on the mount substrate 500 are connected.

The printed circuit board 200 has substantially the same outer shape as the outer shape of the transformer bobbin 120. As shown in FIG. 1B, a primary circuit 210 including an IC 212 and a secondary circuit are provided. 220 are separately arranged in consideration of the creepage distance. Note that, in this example, the printed circuit board 200 has the lower surface arranged as a component mounting surface and is joined to the converter transformer 100 on the upper surface. Further, a plurality of through holes 202 are formed on both sides of the printed circuit board 200, and as described above, the
No. 0 pin 140 is inserted and joined by soldering.

The printed circuit board 200 is formed with a slit 600 that divides the primary circuit 210 and the secondary circuit 220. That is, the slit 600 is formed in a substantially U-shape in plan view so as to surround the secondary circuit 220. And, as described below,
Insulating filler 400 filled in insulating case 300
Are also filled in the slit 600, and the primary side circuit 21
The wiring pattern of 0 and the wiring pattern of the secondary circuit 220 are separated by a reliable insulating structure.

The insulating case 300 is made of an insulating synthetic resin, and is formed in a substantially rectangular parallelepiped container shape surrounding the assembly of the converter transformer 100 and the printed circuit board 200. Is open. The assembly of the converter transformer 100 and the printed circuit board 200 is positioned in the insulating case 300 in a positioning state. Also, the insulating filler 400
Is made of an insulating synthetic resin or the like, and specifically uses a flame-retardant material having a grade of 94V-0 according to the JIS standard for flame resistance.
Then, the insulating filler 400 is used for the insulating case 300.
, And insulates each electronic component and wiring pattern in the insulating case 300. With the insulating structure using the insulating filler 400, the insulating case 3
Each of the electronic components in 00 is protected and has excellent temperature resistance and humidity resistance.

A method for filling the insulating case 300 with the insulating filler 400 is as follows, for example. The insulating case 300 is turned upside down from the state shown in FIG. 1A, that is, the lower surface portion 300A of the insulating case 300 is directed upward. Then, the converter transformer 100 and the printed circuit board 200
Is housed in the insulating case 300. Next, the insulating filler 40 is removed from the lower surface 300A of the insulating case 300.
0 melt is injected. Next, before the filled insulating filler material 400 is solidified, the insulating filler material 400 is vacuumed to remove bubbles from the filled insulating filler material 400, so that the insulating filler material 400 can be removed to the details inside the insulating case 300. Will be filled. In this state, the insulating filler 400 is solidified. In particular, by injecting the melt from the vicinity of the slit 600 of the printed circuit board 200, the slit 60
It is possible to supply the insulating filler 400 within 0, and it is possible to obtain a good filling state for insulation. In addition, by using a bare chip as a semiconductor such as an IC or a diode mounted on the printed circuit board 200, the cost when each semiconductor is filled with the insulating filler 400 can be reduced. The insulating filler 400 filled in the insulating case 300 is:
Inside the converter transformer 100, that is, the core 110
Also, the space between the primary winding and the secondary winding is filled between the coil and the winding 130, so that the inside of the converter transformer 100 can be separated by a reliable insulating structure.

As described above, in the switching power supply of the present embodiment, the slit 600 for separating the primary circuit 210 and the secondary circuit 220 is formed on the printed circuit board 200, and the insulating filler 400 is filled in the slit 600. Since both are insulated by filling, even if the primary circuit 210 and the secondary circuit 220 are brought close to each other, sufficient insulation can be ensured. Therefore, each circuit component can be arranged close to each other, and the mounting area on the printed circuit board 200 can be reduced, so that the size of the printed circuit board 200 can be reduced. As shown in FIG. Can be reduced to an extent having the same outer shape as the converter transformer 100, and can be housed compactly in the insulating case 300, which can contribute to downsizing of the switching power supply device. Further, since each circuit component is accommodated in the insulating case 300, as shown in FIG. 1A, other electronic components 70 arranged around the switching power supply device are provided.
There is no problem even if 0 contacts the insulating case 300, and the distance between the insulating case 300 and the surrounding electronic components can be reduced. The switching power supply thus configured can be handled as one molded component.

In the example of FIG. 1, the trans bobbin 12
A case has been described in which the vertical bobbin is disposed so that the axis of 0 extends in a direction perpendicular to the printed circuit board 200. However, the axis of the transformer bobbin of the converter transformer 100 is in the direction parallel to the printed circuit board 200. The present invention can be applied to the case of a horizontal bobbin disposed so as to extend in the vertical direction, and it is needless to say that the same operation and effect as in the case of the vertical bobbin described above can be obtained. In the case of a horizontal bobbin, the windings of the converter transformer face the printed circuit board 200, but since the insulating case 300 is filled with the filler 400, the core and windings of the converter transformer and the printed circuit board 200 And the insulation between the printed circuit board 200 and the core and winding of the converter transformer can be shortened.

FIG. 2 is a circuit diagram showing an example of a circuit configuration in a molded part using the insulating filler 400 of the switching power supply having the above configuration. The inside of the broken line A in the figure is the configuration inside the molded part in which the insulating case 300 is filled with the filler 400, and the primary side IC 212 and the diode D
1, D2, capacitors C1, C2, resistors R1, R2, etc., a converter transformer 200, a secondary-side diode D3, and the like. Also, primary-side input terminals S1 and S2
The secondary side smoothing circuit 700 and the like are arranged outside the molded part. In the above, the case where the present invention is applied to a switching power supply has been described as an example. However, the present invention can be applied to other power supply devices including a transformer.

[0017]

As described above, in the power supply device of the present invention, the printed circuit board on which the primary side circuit and the secondary side circuit are mounted and the transformer are fixed via the support member and housed in the insulating case. A slit for separating the primary side circuit and the secondary side circuit was formed on the printed circuit board, and an insulating filler was filled in the insulating case and the slit to be integrated. For this reason, the primary circuit and the secondary circuit mounted on the printed circuit board are surrounded by the insulating filler material by the insulating filler filled in the insulating case, and are insulated reliably. By filling the formed slit with the insulating filler, the wiring pattern of the printed circuit board is also reliably separated on the primary side and the secondary side,
A reliable insulating structure can be obtained. Accordingly, the circuit components on the primary side and the secondary side can be shortened and arranged, the power supply device can be formed as a small-sized molded component, and the size of the device can be reduced. Further, by surrounding each circuit component with the insulating filler, heat resistance and humidity resistance can be improved, and reliability can be improved. In addition, safety standards (IEC65
) Can be provided.

[Brief description of the drawings]

FIGS. 1A and 1B are diagrams showing a structure of a switching power supply as one embodiment of the present invention, in which FIG. 1A is a schematic side sectional view, and FIG. 1B is a schematic bottom view of a printed circuit board.

FIG. 2 is a circuit diagram showing an example of a circuit configuration in a molded component using an insulating filler of the switching power supply shown in FIG. 1;

FIG. 3 is a schematic plan view showing a circuit component arrangement in a conventional switching power supply.

[Explanation of symbols]

100 converter transformer 110 core 12
0: transformer bobbin, 130: winding, 140: pin, 200: printed circuit board, 210: primary circuit,
212: IC, 220: Secondary circuit, 300: Insulating case, 400: Insulating filler, 500: Mounting substrate, 600: Slit.

Claims (7)

[Claims] 1. A power supply device for supplying a power supply voltage input from a primary side circuit to a secondary side circuit via a transformer, comprising: a printed circuit board on which the primary side circuit and the secondary side circuit are mounted; A support member fixed to the printed circuit board; an insulating case for accommodating the printed circuit board and the transformer; and a slit formed on the printed circuit board and formed at a position separating the primary circuit and the secondary circuit. A power supply device comprising: an insulating filler that fills the insulating case and the slit. 2. The device according to claim 1, wherein the support member is a pin protruding from a transformer bobbin of the transformer, and the pin is joined to a copper foil portion formed on the printed circuit board by soldering. Power supply. 3. The printed circuit board according to claim 1, wherein the printed circuit board has an outer shape equivalent to the outer shape of the trans bobbin, and the trans bobbin and the printed circuit board are arranged so as to overlap each other at a predetermined interval. The power supply as described. 4. The power supply device according to claim 1, wherein the insulating case is formed of an insulating synthetic resin. 5. The power supply device according to claim 1, wherein the insulating filler is formed of an insulating synthetic resin. 6. A mounting board for mounting the insulating case, wherein a pin protruding from the transformer bobbin extends toward the mounting board, and the pin is soldered to a copper foil portion formed on the mounting board. The power supply device according to claim 2, wherein the power supply device is joined by: 7. The power supply device according to claim 1, wherein the power supply device constitutes a converter section of the switching power supply.