JPH1198819A - Power supply equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce radiation noise by forming a first region of a high conductivity in the proximity of a printed board and forming a second region of a lower conductivity than the first one away from the printed board, in a power supply equipment provided with the main body of an equipment mounted with a rectifier and a high frequency power circuit. SOLUTION: Between an AC input terminal of a full-wave rectifier DB and the main body A of an equipment, capacitors C5 , C6 , C7 which have low impedance against high frequency waves are connected. High frequency current is allowed to flow in a coil 1 for supplying high frequency power from a high frequency power supply RP to generate high frequency electric and magnetic fields and thereby generate visible light by high frequency plasma current in an electrodeless discharge lamp LA. A sheet CS of a higher conductivity than the main body A is fixed in the proximity of a printed board 3. An electric and a magnetic field around the main body A are the vector sums of an electric and a magnetic field due to high frequency current in the direction shown by the arrow Y and an electric and a magnetic field due to high frequency current in the direction shown by the arrow Z, respectively, and therefore are canceled because of the sums of vectors in opposite directions and thereby radiation noise can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply.

[0002]

2. Description of the Related Art FIG. 7 shows a circuit diagram of a conventional example according to the present invention.

In this circuit, an AC input terminal of a full-wave rectifier DB is connected to both ends of an AC power supply AC, an inverter circuit INV is connected to a DC output terminal of the full-wave rectifier DB, and a discharge lamp is connected to an output terminal of the inverter circuit INV. LP and full-wave rectifier DB
And the inverter circuit INV are built in the appliance body A, and the inverter circuit INV is oscillated at a high frequency by a DC voltage full-wave rectified by the full-wave rectifier DB, and the high-frequency voltage is applied to the discharge lamp LP to discharge the discharge lamp LP. It turns on LP. In addition, a capacitor C7 is connected to both ends of the AC power supply AC, an inductor L3 is connected to both ends of the capacitor C7, and a low impedance between the AC input end of the full-wave rectifier DB and the appliance body A with respect to high frequency is obtained. First and second capacitors (hereinafter, referred to as capacitors) C5 and C6 are connected.

[0004] With such a configuration, as shown in FIG.
In addition to the high-frequency current shown by the arrow Y flowing through
A high-frequency current flows in the opposite direction as shown by the arrow Z through the capacitors C5 and C6, and as shown in FIG.
Are the vector sums of the electric field E1 and the magnetic field H1 due to the high-frequency current indicated by the arrow Y and the electric field E2 and the magnetic field H2 due to the high-frequency current indicated by the arrow Z, and the vectors are opposite to each other. Therefore, the absolute value becomes very small, and the radiation noise generated from the instrument body A is reduced.

[0005]

However, in the above conventional example, most of the high-frequency current flowing through the appliance main body A as indicated by arrows Y and Z on the surface of the appliance main body A due to the skin effect of the appliance main body A. When the current flowing on the surface of the instrument body A flows over a wide area, the arrows Y and Z
There are a number of places where high-frequency currents do not flow in opposite directions, as shown by (1), and a problem arises that radiation noise generated from the instrument main body A cannot be sufficiently reduced.

The present invention has been made in view of all of the above problems, and an object of the present invention is to provide a power supply device capable of sufficiently reducing radiated noise generated from an appliance body.

[0007]

According to the first aspect of the present invention, there is provided a filter circuit connected to both ends of an AC power supply, and a rectifier connected to an output terminal of the filter circuit. And a power supply device including an appliance body that houses and arranges a printed circuit board on which a high-frequency power supply circuit that is connected to a DC output terminal of the rectifier and includes at least a switching element and supplies a high-frequency voltage to a load is mounted.
A first region having a higher conductivity is formed close to the printed circuit board, and a second region having a lower conductivity than the first region is formed more distant from the printed circuit board than the first region. I do.

According to the second aspect of the invention, at least one of the first region and the second region is formed in the instrument body.

According to a third aspect of the present invention, the first region is formed at least close to the filter circuit, the rectifier, and the switching element.

According to a fourth aspect of the present invention, the first region is formed of copper. According to the invention described in claim 5, the second region is formed of stainless steel.

According to a sixth aspect of the present invention, a recess is formed near the boundary of the first region.

According to a seventh aspect of the present invention, the concave portion has lower conductivity than the first and second regions.

According to an eighth aspect of the present invention, the load includes an electrodeless discharge lamp.

[0014]

Embodiment

(Embodiment 1) FIG. 1 is a circuit diagram of a first embodiment according to the present invention, FIG. 2A is a schematic sectional view of a main part, and FIG. (B).

The point different from the conventional example shown in FIG. 8 is that a filter circuit FT including capacitors C5, C6 and C7 and a field effect transistor (hereinafter referred to as a switching element).
That is, the copper sheet CS is fixedly arranged on the surface of the instrument body A close to the circuit component connected between Q1 and Q2. Omitted. In this circuit, an electrodeless discharge lamp lighting device is formed with a load of an electrodeless discharge lamp LA in which steam, an inert gas, or the like is sealed in a bulb. Further, the capacitor C7 is connected between the connection point of the capacitors C5 and C6 and the appliance body A, but the capacitor C7 may be provided as appropriate.

Hereinafter, the configuration of this circuit will be briefly described with reference to FIG. In this circuit, an AC input terminal of a full-wave rectifier DB is connected to both ends of an AC power supply AC, and a high-frequency power supply circuit (hereinafter, referred to as a high-frequency power supply) R is connected to a DC output terminal of the full-wave rectifier DB.
P, the high-frequency power supply coil 1 is connected to the output terminal of the high-frequency power supply RP via the matching circuit M, and the electrodeless discharge lamp LA is arranged close to the high-frequency power supply coil 1. . In addition, capacitors C5, C6, and C7 that have low impedance with respect to high frequency are connected between the AC input terminal of the full-wave rectifier DB and the apparatus main body A. And
When a high-frequency current flows from the high-frequency power supply RP to the high-frequency power supply coil 1, a high-frequency electromagnetic field is generated in the high-frequency power supply coil 1, and high-frequency power is supplied to the electrodeless discharge lamp LA. A high-frequency plasma current is generated to generate ultraviolet light or visible light. In addition,
The high-frequency power supply RP connects a series circuit of the switching elements Q1 and Q2 driven by the driving circuit DV to both ends of the full-wave rectifier DB, and provides an inductor between the connection point of the switching elements Q1 and Q2 and the matching circuit M. L
o, connected in series with a capacitor Co.

Instrument body A (for example, having aluminum material)
By arranging a copper sheet CS having a higher conductivity than the fixture body A and closer to the printed circuit board 3, as shown in FIG. The ratio of the high frequency current flowing in the opposite direction is higher in the copper sheet CS than in the appliance body A. Therefore, the electric field and the magnetic field generated around the appliance main body A are the vector sum of the electric field and the magnetic field by the high-frequency current indicated by the arrow Y and the electric field and the magnetic field by the high-frequency current indicated by the arrow Z, and the vectors are opposite to each other. Since they are oriented so as to cancel each other sufficiently, radiation noise generated from the instrument main body A is sufficiently reduced.

(Embodiment 2) FIG. 3 shows a schematic top view of a main part of a second embodiment according to the present invention.

The difference from the first embodiment shown in FIG. 2 is that the printed circuit board 3 has a substantially U-shape, and the same components as those of the other first embodiment have the same reference numerals. The description is omitted by appending a symbol. Even when such a circuit pattern cannot be arranged in a substantially straight line, the copper sheet C
By arranging S on the surface of the instrument body A and closer to the printed circuit board 3 than the instrument body A, radiation noise generated from the instrument body A is sufficiently reduced.

(Embodiment 3) FIG. 4 is a schematic top view of a main part of a third embodiment according to the present invention.

The difference from the first embodiment shown in FIG. 2 is that the copper sheet CS is not disposed and the second sheet has a lower conductivity than the first region where the copper sheet CS is formed. In the region, a stainless steel sheet 4 having a lower conductivity than the appliance body A
Are fixedly arranged, and the conductivity of the first region is relatively increased. The same components as those in the other first embodiment are denoted by the same reference numerals, and description thereof is omitted.

(Embodiment 4) FIG. 5 is a schematic top view of a main part of a fourth embodiment according to the present invention, and FIG. 6 is a cross-sectional view taken along the ab plane.

The difference from the first embodiment shown in FIG. 2 is that the copper sheet CS is not arranged and the concave portion 5 is formed near the boundary of the first region. The same components as those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

With such a configuration, the high-frequency current flowing in the first region is less likely to flow out of the first region, so that the radiation noise generated from the instrument body A is sufficiently reduced. Furthermore, by making the conductivity of the recess 5 lower than that of the first and second regions, the high-frequency current flowing in the first region is reduced to the first region.
Since it becomes more difficult to flow out of the region, the radiation noise generated from the instrument main body A is further sufficiently reduced.

Note that all of the above embodiments may be combined with each other as appropriate.

[0026]

According to the first to eighth aspects of the present invention, it is possible to provide a power supply device capable of sufficiently reducing radiation noise generated from the appliance body.

[Brief description of the drawings]

FIG. 1 shows a circuit diagram of an embodiment according to the present invention.

FIGS. 2A and 2B are a schematic cross-sectional view of a main part and a top view of a main part, respectively, of a first embodiment according to the present invention.

FIG. 3 is a schematic top view of a main part of a second embodiment according to the present invention.

FIG. 4 is a schematic top view of a main part of a third embodiment according to the present invention.

FIG. 5 is a schematic top view of a main part of a fourth embodiment according to the present invention.

FIG. 6 is a cross-sectional view taken along the ab plane according to the embodiment.

FIG. 7 shows a circuit diagram of a conventional example according to the present invention.

FIG. 8 shows a main part circuit diagram according to the conventional example.

FIG. 9 is an operation explanatory diagram according to the conventional example.

[Explanation of symbols]

 A appliance body AC AC power supply DB rectifier FT filter circuit LA electrodeless discharge lamp Q switching element 3 printed circuit board 5 recess

Claims (8)

[Claims] An RF power supply includes a filter circuit connected to both ends of an AC power supply, a rectifier connected to an output terminal of the filter circuit, and at least a switching element connected to a DC output terminal of the rectifier. A high-frequency power supply circuit that supplies and supplies a printed circuit board in which a printed circuit board is housed and arranged, wherein a first region having high conductivity is formed close to the printed circuit board, and a first region having a high conductivity is formed from the first region. A second region having a lower conductivity than the first region, the second region having a lower conductivity than the first region. 2. The power supply device according to claim 1, wherein at least one of the first region and the second region is formed in the appliance body. 3. The device according to claim 1, wherein the first region is formed at least close to the filter circuit, the rectifier, and the switching element.
A power supply according to claim 1. 4. The power supply device according to claim 1, wherein the first region is formed of copper. 5. The power supply device according to claim 1, wherein the second region is formed of stainless steel. 6. The power supply device according to claim 1, wherein a recess is formed near a boundary of the first region. 7. The power supply device according to claim 1, wherein the electric conductivity of the recess is lower than that of the first and second regions. 8. The power supply according to claim 1, wherein the load includes an electrodeless discharge lamp.