JPH0198289A - Connecting method for electrolytic capacitor with power source - Google Patents

Abstract

PURPOSE:To reduce the available temperature of an electrolytic capacitor and to enhance the reliability and life of a power source by forming printed wirings near the terminal position of the capacitor in a meshlike pattern, and connecting the terminals of the capacitor to the ends of conduction wirings provided by branching it from the wirings. CONSTITUTION:A main circuit is formed as printed wirings 2 with broad width on a printed circuit substrate 1, the vicinity of the position of the terminal 4 of an electrolytic capacitor 3 is formed in a meshlike pattern 5 by forming, for example, holes each having 3mm of sides at an interval of 6mm, and the area of the pattern 5 covers at least the mounting area of the capacitor 3. Further, the terminal 4 of the capacitor 3 is connected to the end of conduction wirings 6 branched from the wirings 3 of the main circuit. In this case, the mounting area of the capacitor 3 is so separated as not to be superposed on the wirings 2, and a heat conduction from the wirings 3 can be reduced.

Description

[Detailed Description of the Invention] [) Already Required] Regarding the method of connecting electrolytic capacitors used in power supply devices, which suppresses heat transfer from printed wiring and suppresses temperature rise as much as possible, there is an effective method other than the conventional method. Focusing on whether there is one,
With the aim of creating new solutions, in power supplies using printed wiring boards, the printed wiring near the terminals is made into a mesh pattern to connect the printed wiring and the terminals of the electrolytic capacitor, and the printed wiring of the main circuit is The connection is made using a means that reduces heat conduction, such as by providing a conductive wiring branched from the wiring.

[Industrial application field]

The present invention relates to a method of connecting an electrolytic capacitor to printed wiring, and more particularly, to a method of connecting an electrolytic capacitor using a power supply device, which suppresses heat transfer from the wiring and suppresses temperature rise as much as possible.

Electronic devices using semiconductor ICs use multiple types of power supply voltages, and are low voltage, and devices are becoming smaller and smaller.
Due to the high-density packaging, the supply current for each device light is large, and supplying the entire packaging fraction at υ2 is capacitively
This became difficult in terms of quality and reliability, so the indoor supply was made using one type of relatively high-voltage, highly reliable power source, and each device received power from this, and unit-type power supplies were distributed for each circuit function block within the device. It is installed, converted and supplied to the final voltage.

This power supply has the same mounting structure as the main circuit unit I, but since it handles a large amount of power and generates a large amount of heat, it is necessary to pay sufficient attention to heat dissipation and cooling, especially to suppress the temperature rise of the internal mounted components. , high reliability, and long service life are strongly desired.

[Conventional technology]

FIG. 3 shows an example of a switching regulator power supply circuit.

The power supply device distributed in each device uses a switching regulator circuit as a DC-DC conversion power source.
In most cases, for AC input, an AC-DC converter is added to the input section of the power supply device described above.

An example of a circuit for such a switching regulator power supply is shown in Fig. 3, in which capacitors with large capacity ff1 (C1 to C6) and high voltage resistance (C1 to C3) are not required, and electrolytic capacitors are used. .

When considering the reliability (life span) of this power supply, it is no exaggeration to say that it is determined by the electrolytic capacitor (generally an aluminum foil wet electrolytic capacitor is used).

Currently, the lifespan of this type of electrolytic capacitor is greatly affected by the operating temperature, and is generally 1000 to 1000m at 105°C.
This is because the lifespan is 2,000 hours, which is an order of magnitude shorter than other circuit components, and as a general guideline, it is estimated that a rise in temperature of 10°C will cut the lifespan in half.

Therefore, the operating temperature of the electrolytic capacitor governs the lifespan of the power supply, and in order to reduce this operating temperature, (1) Mount the electrolytic capacitor away from heat-generating components.

(2) Perform mounting with lower mounting density of components.

(3) Perform forced cooling.

(4) Increase the efficiency of the power supply circuit and suppress heat generation.

There are methods such as this, and they have been implemented.

[Problem that the invention seeks to solve]

However, Name et al. (1) Items 1 and 2 above are methods of reducing radiant heat transfer between parts, resulting in an increase in the size of the structure.

(2) The forced cooling described in item 3 above requires air-cooling or liquid-cooling equipment and a corresponding mounting structure, making it complicated and reducing reliability.

(3) Improving the efficiency of the circuit described in item 4 above is the most desirable method, but the current situation is the best and cannot be improved immediately.

There are other problems.

The present invention aims to create a new solution by focusing on whether there are any effective methods other than the above solutions.

[Means for solving problems]

The above problem is as shown in FIGS. 1 and 2 (in a power supply device using a printed wiring board 1, heat conduction is small when connecting the printed wiring 2 and the terminal 4 of the electrolytic capacitor 3). Means: (1) The printed wiring 2 near the terminal 4 position of the electrolytic capacitor 3 is formed into a mesh pattern (5).

(2) Continuous wiring 6 branched from the main circuit printed wiring 2
is provided, and the terminal 4 of the electrolytic capacitor 3 is connected to the tip.

This problem is solved by the method of connecting an electrolytic capacitor for use in a power supply device according to the present invention.

[Function] That is, the purpose is achieved because heat conduction from the printed wiring, which is not considered in the conventional method, is suppressed.

First, considering the basics of heat conduction, simply speaking, heat transfer between two opposing objects is as follows: Q = λS (θ1 - θ2) t//2 Q: Heat transfer area, S: Opposing area , t: time, λ: thermal conductivity, θ: hot water temperature, l: opposing distance. To reduce the heat transfer IQ, (a) reduce the opposing area S.

(b) Increase the facing distance 2.

(C) Inserting a substance with low thermal conductivity λ.

becomes.

However, in an actual power supply device, as shown in the circuit diagram in Figure 1 above, the heat-generating components (transistor Ql, transformer T1, diodes DI, 02, cold coil Ll) are connected to electrolytic capacitors 01 to C6. In addition, because a large current flows,
The printed wiring 2 has a wiring pattern with a line width as wide as possible, and the terminal 4 of the electrolytic capacitor 3 is connected to this wiring pattern.

Copper foil has a high thermal conductivity, and the printed wiring 2 with a wide line width further increases heat conduction, allowing the heat generated by the heat-generating components to be transferred well, and is also transmitted to the electrolytic capacitor 3.

Therefore, as shown in FIGS. 1 and 2, (a) the connection part of the printed wiring 2 with a wide line width of the main circuit is formed into a mesh pattern 5 to reduce the heat transfer area, etc., to reduce the heat conduction. By connecting the electrolytic capacitor 3 using a means to
It is not carried out over the entire surface of the electrolytic capacitor 3, but only near the terminal 4 position of the electrolytic capacitor 3.

If it were applied to the entire surface, it would be thermally favorable, but the electrical resistance would increase and there is a risk that it would have an adverse effect, so it is applied only partially to suppress the effect.

〔Example〕

The present invention will be specifically described below with reference to embodiments shown in the drawings.

FIG. 1 shows a first embodiment of the invention, and FIG. 2 shows a second embodiment of the invention.

The experiment was carried out on a power supply device using a switching regulator circuit and having a printed wiring board mounting structure, as shown in FIG. 3, as a DC-DC conversion power supply.

In the first embodiment, as shown in FIG. 1, the main circuit is printed wiring 2 with a wide line width on a printed wiring board 1, and the vicinity of the terminal 4 of the electrolytic capacitor 3 has a 3-body square hole 6fflIT1.
A mesh pattern 5 is formed at intervals, and the area of the mesh pattern 5 is such that it covers at least the mounting area of the connected electrolytic capacitor 3.

In the second embodiment, as shown in FIG. 2, a conductive wiring 6 is provided branching from a wide printed wiring 2 of the main circuit, and a terminal 4 of an electrolytic capacitor 3 is connected to the tip of the conductive wiring 6.
In this case, it is important to keep the mounting area of the electrolytic capacitor 3 and the printed wiring 2 apart so that they do not overlap.

In this way, by implementing the present invention without changing the external shape or cooling structure from the conventional device, the temperature of the electrolytic capacitor could be lowered by about 5°C.

The above embodiment shows one example, and the shape and dimensions of the mesh pattern 5 and the dimensions of the conductive wiring 6 are not limited to those described above. Other effective means for reducing heat conduction may also be used.

〔Effect of the invention〕

As described above, according to the present invention, an effective new method other than the conventional method has been created, which makes it possible to further reduce the operating temperature of electrolytic capacitors under the same mounting conditions, without increasing costs, and increasing the reliability of power supply devices. The effects of this are significant, as they can be made more durable and have a longer lifespan.

[Brief explanation of the drawing]

FIG. 1 shows a first embodiment of the invention, and FIG. 2 shows a second embodiment of the invention. FIG. 3 is an example of a switching regulator power supply circuit. In the diagram, 1 is a printed wiring board, 2 is a printed wiring, 3 is an electrolytic capacitor, 4 is a terminal, Agony Zinnazu (/Giyushi-2 and JE) famous side voice 32

Claims (3)

[Claims] (1) In a power supply device using a printed wiring board (1), the printed wiring (2) and the terminals of the electrolytic capacitor (3) (
4) A method for connecting an electrolytic capacitor for use in a power supply device, characterized in that the connection is made using a means that reduces heat conduction. (2) As a means for reducing heat conduction, the printed wiring (2) near the terminal (4) position of the electrolytic capacitor (3) is formed into a mesh pattern (5). A method for connecting an electrolytic capacitor for use in the power supply device according to item 1. (3) As a means to reduce heat conduction, a conductive wiring (6) is provided branching off from the printed wiring (2) of the main circuit, and the terminal (4) of the electrolytic capacitor (3) is connected to the tip. A method for connecting an electrolytic capacitor for use in a power supply device according to claim 1.