JP2002345245A - Switching power supply - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a switching power supply which assures higher mounted component density, easier reduction in size, small resistance loss at the terminal connecting point and higher power supply efficiency. SOLUTION: This switching power supply is composed of a transformer 11 mounted on the predetermined board 14, a coil leadout portion 13 for the coil of the transformer 11 and the other components 16 fixed to the board 14 and connected to the transformer 11. This switching power supply also comprises a metal plate electrode member 19 located at the upper part of the mounted components 16 and electrically connected to the mounted components to form a main current path. The coil leadout portion 13 is overlapped directly on the mounted components 16 and electrically connected to the electrode member 19.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switching power supply device having a transformer mounted on a circuit board and used in various electronic devices.

[0002]

2. Description of the Related Art Conventionally, a transformer used for a switching power supply device capable of outputting a large current is connected to a circuit pattern and various mounting parts by a primary winding and a secondary winding of a transformer 1.
This is performed by the lead portions 2 and 3 of the next winding. The lead portions 2 and 3 are formed of a thin plate-shaped copper plate or an end of an edgewise winding. As shown in FIGS. 3 and 4, the electrical connection structure of the transformer 1 and other mounted components is such that the winding lead-out portion 3 of the transformer 1 is bent in a crank shape by 90 ° to form an electrical connection portion 3a. The electrical connection portion 3a is provided on the surface of the main current wiring pattern 5 formed on the surface of the printed wiring board 4.
Was directly connected and soldered.

As a mounted component to which the transformer 1 is connected, there is, for example, a surface-mounted diode element 6. One terminal (not shown) of the diode element 6 is connected to a wiring pattern 8 for connecting other mounted components to the printed wiring board 4,
The other electrical connection terminal 7 is electrically connected to a metal plate-shaped electrode plate 9 for a main current path. The electrode plate 9 for the main current path has a terminal portion 9a provided at an end thereof, and the terminal portion 9a is bent in a crank shape by 90 ° to form an electrical connection portion 9b. Then, the electrode plate 9 to which the lead portion 3 of the transformer 1 and the diode element 6 are connected is directly connected to the main current wiring pattern 5 and soldered so that the main current can flow mutually.

[0004]

In the case of the above-mentioned prior art, the main current wiring pattern 5 in which the lead portion 3 of the transformer 1 and the electrode plate 9 are connected is capable of supplying a main current, and therefore requires a large area. As a result, the mounting of other components is hindered, and the component mounting density is reduced, which hinders miniaturization of the power supply. Furthermore, when the component mounting density is increased, the main current wiring pattern 5 cannot be made so large, so that the resistance loss due to the increase in the current density is large, which causes the power supply efficiency to deteriorate.

The present invention has been made in view of the above-mentioned problems of the prior art, and can increase the mounting density of components, can be easily miniaturized, has low resistance loss at terminal connecting portions, It is an object to provide a switching power supply device with high power supply efficiency.

[0006]

According to the present invention, there is provided a transformer mounted on a predetermined substrate, a winding lead-out portion of the transformer, a mounted component fixed to the substrate and connected to the transformer, and a mounted component. A metal plate-shaped electrode member such as a copper plate, which is electrically connected to the mounting component and forms a main current path at the upper portion, and the lead portion is directly superimposed on the mounting component on the mounting member, A switching power supply device that is electrically connected. The lead portion is extended from a metal plate-shaped winding, and an end of the lead portion is connected to the electrode member.

According to the switching power supply device of the present invention, a winding lead portion is directly connected to an electrode member connected to a mounted component, and a wiring pattern for connecting the drawn portion to the electrode member of the mounted component, and a wiring pattern thereof. This does not require a space for connecting to the substrate, and reduces the mounting area.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 and 2 show an embodiment of the present invention. A connection structure between a transformer of this embodiment and other mounted components is used for a switching power supply device 10 capable of outputting a large current. Primary, 2
A transformer 11 having a secondary winding and a ferrite core or the like is provided, and lead portions 12 and 13 of a primary winding and a secondary winding of the transformer 11 project sideways. The transformer 11 is surface-mounted on a printed wiring board 14. In the case of a copper plate coil, the lead portions 12 and 13 are formed of a copper plate processed into a shape capable of connecting the ends of the annular coil, and in the case of an edgewise wound coil, a rectangular wire edgewise winding in a transformer is used. And a plate-like end extending from the end.

As shown in FIGS. 1 and 2, a diode element 16 which is a mounting component connected to the transformer 11 is surface-mounted on a printed wiring board 14 near the transformer 11. One of the terminals of the diode element 16 is connected to a wiring pattern 18 for connecting other mounted components on the printed wiring board 14, and the other electrical connection terminal 17 protrudes upward. The connection terminal 17 is provided with a through hole 2 formed in an electrode plate 19 which is a metal plate-shaped electrode member for a main current path.
0 and soldered.

The main current path electrode plate 19 is formed in a rectangular shape, for example, as shown in the figure, and is located parallel to the printed wiring board 14. At the end of the electrode plate 19 on the side of the transformer 11, an electrode connection portion in which the drawer 13 is bent in a crank shape by 90 ° so that the back surface of the drawer 13 a is positioned at the same height as the surface of the electrode plate 19. 13a are overlapped and soldered and connected. The bending of the winding lead portion 13 may be adjusted to the height of the electrode plate 19.
If they are at the same height, there is no need to bend.

The switching power supply of this embodiment is
The electrical connection between the lead-out portion 13 of the transformer 11 and the diode element 16 as another mounting component is established by the diode element 16
Is directly soldered to the electrode plate 19 provided above the wiring board, so that a wiring pattern and space required for connection between the transformer 11 and the diode element 16 are unnecessary, and are occupied by these mounted components. The area can be reduced. Therefore, the mounting density can be increased, which contributes to downsizing of the power supply device. Further, the lead portion 1 of the transformer 11 is directly connected to the electrode plate 19 for the main current path.
3 is connected, the current density of the main current path is reduced, the loss is reduced, and a highly efficient power supply device can be configured.

The mounting components and the circuit board of the switching power supply according to the present invention can be changed as appropriate, and the shape of the lead portion and the shape of the electrode member can be appropriately set other than the plate shape.

[0013]

According to the switching power supply device of the present invention, the space for the main current wiring pattern and the like required for connecting the transformer and other mounted components is not required, so that the component mounting density on the substrate can be increased. Furthermore, the current density at the connection part can be reduced, and the loss at the connection part is reduced because the electrode member connecting the other mounted parts and the lead part of the transformer are directly connected to form the main current path. In addition, it is possible to configure a highly efficient power supply with downsizing.

[Brief description of the drawings]

FIG. 1 is a partially broken plan view showing a connection portion between a switching power supply transformer according to an embodiment of the present invention and another mounted component.

FIG. 2 is a partially broken front view showing a connection portion between the switching power supply transformer according to the embodiment of the present invention and another mounted component.

FIG. 3 is a partially broken plan view showing a connection portion between a conventional switching power supply transformer and another mounted component.

FIG. 4 is a partially cutaway front view showing a connection portion between a conventional switching power supply transformer and another mounted component.

[Explanation of symbols]

 1,11 Transformer 2,3,12,13 Lead-out part 3a, 13a Connection part 4,14 Printed wiring board 6,16 Diode element 7,17 Terminal 8,18 Wiring pattern for connecting other mounted parts 9,19 Electrode plate

Claims (2)

[Claims] A transformer mounted on a predetermined substrate, a lead portion of a winding of the transformer, another mounting component fixed to the substrate and connected to the transformer, and A metal plate-shaped electrode member that is electrically connected to the mounting component and forms a main current path, and that the lead portion is directly overlapped on the mounting component and is electrically connected to the electrode member. Characteristic switching power supply. 2. The switching power supply device according to claim 1, wherein the lead portion has a shape of a metal plate extending from the winding, and an end of the lead portion is connected to the electrode member.