JP2002354842A - Power source unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power source unit having structure which can reduce mutual electromagnetic reaction between an inductance element and other circuit components, without a second metal case and without restricting a mounting direction of the inductance element. SOLUTION: This power source unit is equipped with a printed board 1 on which circuit components are mounted, a first and a second FETs 3a and 3b which are mounted on the printed board 1 and have radiation surfaces 2a, 2b almost in parallel with the printed wiring board 1, an inductance element 6 mounted on the same side of the board 1 as the first and second FETs 3a and 3b, and a metal case 5 in which a first and a second protruding parts 5a, 5b having contact surfaces 4a, 4b in close contact with the radiation surfaces 2a, 2b of the first and second FETs 3a and 3b are formed on the internal surface. In the state that the printed 1 is accommodated in the metal case 5, the inductance element 6 is arranged between the first and second FETs 3a and 3b in close contact with the contact surfaces 4a, 4b of the first and the second protruding parts 5a and 5b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device used for a lighting device of an electrodeless discharge lamp and covered with a metal case for electromagnetic shielding.

[0002]

2. Description of the Related Art Japanese Patent Application Laid-Open No. 9-1 / 1991 discloses this type of power supply device.
There is one described in Japanese Patent No. 9164. FIG. 14 (a)
(B) shows a top view and a bottom view of this conventional power supply device. FIG. 14C is a perspective view of a high-frequency circuit (case) included in the power supply device.

In this power supply device, a printed board 101 is accommodated in a metal case 100, and a high-frequency circuit 102 and a power supply circuit 103 are mounted on the printed board 101. The high-frequency circuit 102 has a plurality of projections (claws) 108a to 108a on its opening side as shown in FIG.
8f is covered with the second metal case 107 formed. The protrusions 108a to 108f are
The second metal case 107 (the high-frequency circuit 102 housed in the second metal case 107) is fixed to the printed circuit board 101 by the small holes 105a to 105f.

As described above, by covering the entire power supply device with the metal case 100, electromagnetic interference (EMI) between the power supply device and an external circuit is prevented by the shielding effect, and the high-frequency circuit 102 is protected by the second metal case 107. Covering prevents electromagnetic interference (interference) between components (between the high-frequency circuit 102 and the power supply circuit 103) inside the power supply device.

[0005]

However, as described above, the second metal case 107 is placed in the metal case 100.
Is disadvantageous in that the cost is high and also serves as a barrier to miniaturization. If the second metal case 107 is omitted, size reduction and cost reduction can be achieved, but adverse effects (interference) between components, particularly between inductance elements, become a problem. This is because mutual induction occurs due to a part of the magnetic flux generated from one inductance element interlinking with the coil of the other inductance element.

In order to reduce this adverse effect, it is conceivable to limit the mounting direction of a plurality of adjacent inductance elements so that magnetic fluxes that interlink with each other are hardly generated. In other words, by making the winding directions of the coils different from each other by approximately 90 degrees, mutual induction is less likely to occur. However, such a limitation on the mounting direction is often a barrier to miniaturization, and it may be difficult to make the winding directions of the coils different from each other by approximately 90 degrees.

The present invention has been made in view of the above problems, and does not require a second metal case for preventing mutual electromagnetic action between an inductance element and other circuit components. An object of the present invention is to provide a power supply device having a structure capable of reducing a mutual electromagnetic action between an inductance element and another circuit component without limiting the mounting direction of the element.

[0008]

According to a first aspect of the present invention, there is provided a power supply device comprising: a printed circuit board on which circuit components are mounted;
First and second heating elements mounted on the printed circuit board and having heat dissipation surfaces substantially parallel to the printed circuit board; and an inductance element mounted on the same surface of the printed circuit board as the first and second heating elements. A metal case having first and second protrusions formed on an inner surface thereof, the metal case having a contact surface in close contact with a heat radiation surface of the first and second heating elements, and the printed circuit board is housed in the metal case. In this state, the inductance element is disposed between the first and second protrusions and the first and second heating elements that are in close contact with the contact surfaces thereof.

According to such a configuration, the first and second heat generating elements (for example, F) in which the first and second protrusions formed on the inner surface of the metal case and the heat radiating surface are tightly fixed to the contact surfaces thereof.
ET) surrounds the inductance element to provide a shielding effect. An inductance element and another circuit part (for example, a second inductance element) can be used without requiring a second metal case for preventing mutual electromagnetic action between circuit parts and without limiting the mounting direction of the inductance element. Is reduced, and a stable operation is obtained.

Preferably, the first and second protrusions protrude from an inner surface of the metal case substantially perpendicular to the printed circuit board, and the first and second heat generating portions are provided on one side of the printed circuit board near the inner surface. An element and the inductance element are mounted, and the inductance element includes first and second protrusions of the metal case and the inner surface.
It is enclosed from the direction. Of course, a structure is also possible in which the first and second protrusions protrude from the inner surface of the metal case substantially parallel to the printed circuit board, and the leading end surfaces serve as contact surfaces.

A circuit element having a metal part is mounted on the printed circuit board between the first and second heating elements so as to be aligned with the inductance element, and the first and second circuit elements are arranged with respect to the inductance element. The circuit element having the metal portion is disposed on the side opposite to the inner surface on which the protrusion is formed, so that the inductance element includes the first and second protrusions of the metal case, the inner surface, and the metal portion. A structure surrounded by at least four directions including a circuit element having the following is also preferable. In this case, the shielding effect surrounding the inductance element is further enhanced as compared with the case where there is no circuit element having a metal part.

As the circuit element having the above-described metal part, an electrolytic capacitor, a variable capacitor, a second heat generating element having a heat-dissipating metal part, or the like can be used.

Further, a circuit element having a metal part is provided such that a terminal connected to a stable potential is closer to the inductance element than other terminals among a plurality of terminals of the circuit element having the metal part. Is preferably determined. Thereby, the shielding effect by the circuit element having the metal part is enhanced.

In the printed circuit board, when the first and second heat generating elements and the circuit element having the metal part are mounted with a second inductance element outside a region surrounding the inductance element, Mutual induction between the inductance element and the second inductance element is effectively reduced. This is particularly effective when the frequency of the voltage applied to the second inductance element is substantially equal to the frequency of the voltage applied to the inductance element.

As an example of a specific circuit configuration, the inductance element is connected between terminals of the first and second heating elements. Alternatively, the inductance element is connected between the heating element and a power supply, and the second inductance element is connected between the heating element and a load.

In the case where at least one of the inductance element and the second inductance element is an air-core coil element or a coil element formed by winding a coil around a rod-shaped magnetic body, the shielding effect of the structure of the present invention is particularly improved. It is utilized.

An electrodeless discharge lamp can be connected as a load of the power supply device as described above and used as a lighting device for the electrodeless discharge lamp.

Further, the power supply device according to the present invention comprises a printed circuit board on which circuit components are mounted, first and second heating elements mounted on the printed circuit board and having a heat radiation surface substantially parallel to the printed circuit board, First and second protrusions having an inductance element mounted on the same surface of the printed circuit board as the first and second heating elements, and a contact surface in close contact with a heat radiation surface of the first and second heating elements. And a metal case formed on an inner surface of the printed circuit board. The first and second protrusions are in close contact with the contact surfaces thereof in a state where the printed circuit board is accommodated in the metal case. The inductance element is arranged between the heating elements, and a circuit element having a metal part is mounted on the printed board between the first and second heating elements so as to be aligned with the inductance element; With respect to the inductance element, a circuit element having the metal part is disposed on the opposite side to the inner surface on which the first and second protrusions are formed, so that the inductance element becomes the first and second parts of the metal case. The printed circuit board is surrounded by at least four directions including the protruding portion, the inner surface, and the circuit element having the metal portion, and the circuit element having the first and second heating elements and the metal portion forms the inductance element on the printed circuit board. A second inductance element is mounted outside the surrounding area, and an electrodeless discharge lamp is connected as a load.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. A first embodiment will be described with reference to FIGS. FIGS. 1A and 1B are a plan view and a side view showing a printed circuit board and main mounting components of the power supply device according to the first embodiment. On the printed circuit board 1, FETs (field effect transistors) 3a and 3b, which are first and second heating elements, and an inductance element 6 are mounted. The first and second FETs 3a and 3b have heat radiation surfaces 2a and 2b substantially parallel to the printed circuit board 1, respectively. Usually, the heat radiating surfaces 2a and 2b are fixed so as to be in close contact with the contact surface of the metal heat sink. Further, the inductance element 6 is arranged between the first and second FETs 3a and 3b.

FIGS. 2A and 2B are a sectional view in plan view and a sectional view in side view showing the metal case of the power supply device according to the first embodiment. FIG. 2B is a side sectional view of FIG.
It is L1 cross section in the top view cross-sectional view of (a). First and second protrusions 5 having contact surfaces 4a and 4b are provided on the inner surface of the metal case 5 (the inner surface substantially parallel to the printed circuit board 1).
a and 5b are formed.

FIG. 3 is a side sectional view showing the assembled state in which the printed circuit board is housed in the metal case of the power supply device according to the first embodiment. As can be seen from this figure, the contact surfaces 4a and 4b of the first and second protrusions 5a and 5b formed on the inner surface of the metal case 5 are connected to the heat radiation surfaces 2a and 2b of the first and second FETs 3a and 3b. Each is in close contact. That is, the first and second protrusions 5a and 5b
The metal case 5 including the first and second FETs 3a and 3
b functions as a heat sink.

The first and second projections 5a and 5b formed on the inner surface of the metal case 5 and their contact surfaces 4a, 4b
b and the first and second FETs 3a and 3b tightly fixed to
The (metal portion of) also acts as an electromagnetic shield that covers the inductance element 6. That is, the first and second projections 5a and 5b formed on the inner surface of the metal case 5 and the first and second FETs tightly fixed to the contact surfaces 4a and 4b.
By arranging 3a and 3b so as to sandwich inductance element 6, mutual electromagnetic action between inductance element 6 and other circuit components is reduced.

As a result, the mutual electromagnetic action between the inductance element 6 and other circuit components is reduced without using the second metal case for shielding, and the operation of the power supply circuit is stabilized. Further, it is not necessary to devise to reduce mutual electromagnetic induction by providing a restriction on the mounting direction of the inductance element 6 and another circuit component (such as an inductance element). Of course, if such a restriction of the mounting direction is possible, it may be implemented together with the configuration of the present embodiment.

Next, a second embodiment will be described with reference to FIGS. FIG. 4 is a plan view showing a printed circuit board and main mounting components of the power supply device according to the second embodiment. Similarly to the first embodiment, FETs 3a and 3b, which are first and second heating elements, and an inductance element 6 are mounted on the printed circuit board 1, and the first and second FETs 3a and 3b are mounted.
The inductance element 6 is arranged between the points b. First
In the second embodiment, these elements are mounted substantially at the center of the printed circuit board 1. In the second embodiment, these elements are mounted so as to be closer to one side of the printed circuit board 1. The first and second FETs 3a and 3b have heat radiation surfaces 2a and 2b substantially parallel to the printed circuit board 1.

FIG. 5 is a sectional plan view showing a metal case of the power supply device according to the second embodiment. In the first embodiment, the first and second protrusions 5a and 5b are formed at substantially the center of the inner surface of the metal case 5 substantially parallel to the printed board 1, whereas in the second embodiment, Printed circuit board 1
First and second protruding portions 5a and 5b are formed so as to protrude from an inner surface 7 substantially perpendicular to. The contact surfaces 4a and 4b are formed on the side surfaces of the first and second protrusions 5a and 5b. The opposite sides of the first and second protrusions 5a and 5b from the contact surfaces 4a and 4b may be connected to the inner surface of the metal case 5 (an inner surface substantially parallel to the printed circuit board 1), or a gap may be formed. It may be.

Also in this embodiment, the contact surfaces 4a and 4b of the first and second protrusions 5a and 5b formed on the inner surface of the metal case 5 are used as the heat radiation surfaces 2a and 2b of the first and second FETs 3a and 3b. And the metal case 5 including the first and second protrusions 5a and 5b functions as a heat sink for the first and second FETs 3a and 3b. The first and second projections 5a and 5b formed on the inner surface of the metal case 5 and the first and second FETs 3a and 3b tightly fixed to the contact surfaces 4a and 4b are connected to the inductance element 6.
, And the inductance element 6 is
Are enclosed from three directions.

As a result, the mutual electromagnetic action between the inductance element 6 and other circuit components is reduced without using the second metal case for electromagnetic shielding, and the operation of the power supply circuit is stabilized.

FIG. 6 is a plan view showing a printed circuit board and main mounted components of a power supply device according to a third embodiment. In this embodiment, in addition to the configuration of the second embodiment, a circuit element 8 having a metal part is mounted on the printed circuit board 1. The circuit element 8 having a metal part is arranged between the first and second FETs 3a and 3b so as to be aligned with the inductance element 6 and on the opposite side of the inductance element 6 from the inner surface 7 of the metal case 5. .
Therefore, the inductance element 6 is surrounded from four directions of the inner surface 7 of the metal case 5, the first and second protrusions 5a and 5b, and the circuit element 8 having the metal part.

As a result, the mutual electromagnetic action between the inductance element 6 and other circuit components is further reduced without using the second metal case for the electromagnetic shield, and the operation of the power supply circuit is stabilized. In the example shown in FIG. 6, an aluminum electrolytic capacitor is mounted as the circuit element 8 having a metal part.

FIG. 7 is a plan view showing a printed circuit board and main mounted components of a power supply device according to a modification of the third embodiment. In this modification, a third heating element (FET) having a metal part for heat dissipation similar to the first and second FETs 3a and 3b is mounted as the circuit element 8 having a metal part. In the example shown in FIG. 7, the circuit element 8 is mounted vertically (standing) on the printed circuit board 1 in order to enhance the shielding effect of the metal part of the circuit element 8.

FIG. 8 is a plan view showing a printed circuit board and main mounting components of a power supply device according to another modification of the third embodiment. In this modification, a variable capacitor using a metal plate is mounted as the circuit element 8 having a metal part.

In the embodiment shown in FIGS. 6 to 8, of the plurality of terminals of the circuit element 8 having a metal part, the terminal connected to a stable potential is closer to the inductance element 6 than the other terminals. In addition, it is preferable that the mounting direction of the circuit element 8 having the metal part is determined. By doing so, the electromagnetic shielding effect by the circuit element 8 having the metal portion surrounding the inductance element 6 together with the inner surface 7 of the metal case 5 and the first and second protrusions 5a and 5b is enhanced.

FIG. 9 is a plan view showing a printed circuit board and main mounting components of a power supply unit according to still another modification of the third embodiment. In this modification, the second inductance element 9 is mounted on the printed circuit board 1 and the first and second FEs are mounted.
The second inductance element 9 is located outside the region where the circuit element 8 having T3a and 3b and the metal part surrounds the inductance element 6.

With such an arrangement, even when the distance between the inductance element 6 and the second inductance element 9 is relatively short, the mutual induction between the two can be reduced. It is not necessary to devise so that the mounting direction (coil winding direction) of the inductance element 6 and the second inductance element 9 is not parallel.

FIGS. 10 and 11 show circuit examples of the power supply device according to the embodiment shown in FIGS. In the circuit of FIG. 10, the drain terminal of the first FET 3a and the second F3
The inductance element 6 is connected to the capacitor 11 connected to the gate terminal of the ET 3b. The arrangement of the components can be determined so that the series circuit of the inductance element 6 and the capacitor 11 connects the first and second FETs 3a and 3b on the actual printed circuit board 1 with the shortest distance. It is effective for operation and good high frequency characteristics.

In the circuit shown in FIG. 11, the inductance element 6 is connected between the drain terminal of the second FET 3b and the power supply, and the drain terminal of the FET 3 is connected to the load via the second inductance element 9 and the capacitor 11. It is connected. In this case, even when the two inductance elements 6 and 9 operate at substantially the same frequency, the interference between the two inductance elements 6 and 9 is reduced by the above-described shielding effect. 9 can be arranged relatively close. As a result, both miniaturization and stable operation of the device can be achieved.

FIG. 12 is a plan view showing a printed circuit board and main mounted components of the power supply device according to the fourth embodiment. In this embodiment, in the embodiment shown in FIG. 9, a structure in which a coil is wound around a rod-shaped magnetic body is used as the inductance element 6 and the second inductance element 9. As described above, even when an inductance element that emits magnetic flux not only in a magnetic material but also in the air is used, interference between the two inductance elements 6 and 9 is effectively reduced by the above-described shielding effect.
The same effect can be obtained when an air-core coil element is used as both inductance elements 6 and 9.

FIG. 13 is a circuit diagram showing an example of use of the power supply device according to the embodiment of the present invention. This circuit is obtained by connecting an electrodeless discharge lamp as a load to the power supply device shown in FIG. As shown in FIG. 13, a high-frequency induction coil 12 and a capacitor 13 constituting an electrodeless discharge lamp are connected in parallel to the output side of a power supply device. The high frequency induction coil 12 is wound around a light emitting bulb 14 containing mercury vapor. A phosphor is applied to the inner surface (glass surface) of the light emitting bulb 14. Ultraviolet light is excited from the mercury vapor inside the light emitting bulb 14 by the high frequency induction coil 12, and the ultraviolet light excites the fluorescent material, so that the entire light emitting bulb 14 emits light efficiently.

Although the present invention has been described with reference to some embodiments and modifications, the present invention can be embodied in various other forms.

[0040]

As described above, according to the present invention, the first and second protruding portions formed on the inner surface of the metal case and the first and second heat generating portions closely fixed to the contact surfaces thereof. Since the element and the like are arranged so as to surround the inductance element and exhibit a shielding effect, the adverse effect between the inductance element and other circuit components (second inductance element) without using the second metal case for shielding. Is reduced, and the operation of the circuit is stabilized.

[0041]

[Brief description of the drawings]

FIGS. 1A and 1B are a plan view and a side view, respectively, of a printed circuit board and main mounting components of a power supply device according to a first embodiment.

FIGS. 2A and 2B are a plan view cross-sectional view and a side view cross-sectional view, respectively, of the metal case of the power supply device according to the first embodiment.

FIG. 3 is a side sectional view showing an assembled state in which a printed circuit board is accommodated in a metal case of the power supply device according to the first embodiment.

FIG. 4 is a plan view showing a printed circuit board and main mounting components of a power supply device according to a second embodiment.

FIG. 5 is a plan sectional view showing a metal case of a power supply device according to a second embodiment.

FIG. 6 is a plan view showing a printed circuit board and main mounting components of a power supply device according to a third embodiment.

FIG. 7 is a plan view showing a printed circuit board and main mounted components of a power supply device according to a modification of the third embodiment.

FIG. 8 is a plan view showing a printed circuit board and main mounted components of a power supply device according to another modification of the third embodiment.

FIG. 9 is a plan view showing a printed circuit board and main mounting components of a power supply device according to still another modification of the third embodiment.

FIG. 10 is a diagram illustrating a circuit example of a main part of the power supply device according to each embodiment.

FIG. 11 is a diagram illustrating another circuit example of a main part of the power supply device according to each embodiment.

FIG. 12 is a plan view showing a printed circuit board and main mounting components of a power supply device according to a fourth embodiment.

FIG. 13 is a circuit diagram showing a usage example of the power supply device according to the embodiment of the present invention.

14A is a top view of a conventional power supply device, FIG.
(B) is a bottom view, and (c) is a perspective view of a high-frequency circuit (case).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Printed circuit board 2a, 2b Heat radiating surface 3a, 3b FET (heating element) 4a, 4b Contact surface 5 Metal case 5a, 5b Projecting part 6 Inductance element 8 Circuit element having metal part 9 Second inductance element

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3K072 AA16 BC01 CA16 CB10 FA09 GA02 GB04 5H007 AA01 BB03 CA02 CB07 HA01 HA03

Claims (12)

[Claims] A printed circuit board on which circuit components are mounted;
First and second heating elements mounted on the printed circuit board and having heat dissipation surfaces substantially parallel to the printed circuit board; and an inductance element mounted on the same surface of the printed circuit board as the first and second heating elements. A metal case having first and second protrusions formed on an inner surface thereof having a contact surface closely contacting a heat radiation surface of the first and second heating elements, wherein the printed circuit board is accommodated in the metal case. In the power supply device, the inductance element is disposed between the first and second protrusions and the first and second heating elements in close contact with their contact surfaces. 2. The first and second projecting portions project from an inner surface of the metal case substantially perpendicular to the printed circuit board, and the first and second heating elements are provided on one side of the printed circuit board near the inner surface. The power supply device according to claim 1, wherein the inductance element is mounted on the metal case, and the inductance element is surrounded from at least three directions including first and second protrusions of the metal case and the inner surface. . 3. A circuit element having a metal part is mounted on the printed circuit board between the first and second heating elements so as to be aligned with the inductance element, and the first and second circuit elements are arranged with respect to the inductance element. The circuit element having the metal portion is disposed on the side opposite to the inner surface on which the protrusion is formed, so that the inductance element includes the first and second protrusions of the metal case, the inner surface, and the metal portion. 3. The power supply device according to claim 2, wherein the power supply device is surrounded from at least four directions including a circuit element having the following. 4. The power supply device according to claim 3, wherein the circuit element having the metal part is any one of an electrolytic capacitor, a variable capacitor, and a third heating element having a metal part for heat radiation. 5. A circuit element having a metal part such that a terminal connected to a stable potential is closer to the inductance element than other terminals among a plurality of terminals of the circuit element having the metal part. 5. The power supply device according to claim 3, wherein a mounting direction of the power supply is determined. 6. The printed circuit board, wherein the first and second heating elements and a circuit element having the metal part have a second inductance element mounted outside a region surrounding the inductance element. The power supply device according to claim 3, 4 or 5, wherein 7. The power supply according to claim 6, wherein the frequency of the voltage applied to the second inductance element is substantially equal to the frequency of the voltage applied to the inductance element. 8. The power supply device according to claim 1, wherein said inductance element is connected between terminals of said first and second heating elements. 9. The device according to claim 1, wherein the inductance element is connected between the heating element and a power supply, and the second inductance element is connected between the heating element and a load. The power supply device according to any one of claims 7 to 10. 10. The inductance element and the second element.
The power supply device according to any one of claims 1 to 9, wherein at least one of the inductance elements is an air-core coil element or a coil element formed by winding a coil around a rod-shaped magnetic body. 11. The power supply device according to claim 1, wherein an electrodeless discharge lamp is connected as a load. 12. A printed circuit board on which circuit components are mounted, first and second heating elements mounted on the printed circuit board and having heat dissipation surfaces substantially parallel to the printed circuit board, and the first and second heating elements of the printed circuit board. Metal having an inductance element mounted on the same surface as the second heating element and first and second protrusions having a contact surface in close contact with the heat radiation surface of the first and second heating elements formed on the inner surface. A case, wherein the printed circuit board is accommodated in the metal case, and the inductance is provided between the first and second protrusions and the first and second heating elements in close contact with the contact surfaces thereof. A circuit element having a metal part is mounted on the printed circuit board between the first and second heating elements so as to be aligned with the inductance element. The circuit element having the metal part is disposed on the side opposite to the inner surface on which the first and second protrusions are formed, so that the inductance element is in contact with the first and second protrusions of the metal case. The inner surface is surrounded by at least four directions including the circuit element having the metal part, and the first and second heating elements and the circuit element having the metal part in the region surrounding the inductance element on the printed circuit board. A power supply device, wherein a second inductance element is mounted outside and an electrodeless discharge lamp is connected as a load.