JPH0193091A - Electronic stabilizer for electric discharge lamp - Google Patents

Abstract

PURPOSE:To miniaturize and realize lightness of a stabilizer by laminating insulation layers on the bottom plate of a casing, and connectively fixing various circuit parts including an invertor on the insulation layer via a circuit pattern when the various circuit parts, which is including a high frequency invertor used for a lighting control part of an electric discharge lamp, is housed in a metallic casing. CONSTITUTION:Insulation layers 12 having a thickness of 200-600mum are lami nated on a bottom plate 11a of a metallic casing 11, and a circuit pattern 13 composed of a copper foil etc., is laminated on the insulation layer. Then vari ous circuit parts 14 including an invertor and other circuit parts 14 are attached on the middle part and an adjacent position respectively. This makes it possible to lower the height of the casing 11, and to reduce cost as well.

Description

[Detailed description of the invention] [Industrial use] This invention relates to improvements in electronic ballasts for discharge lamps.

[Prior Art] An electronic ballast for a discharge lamp uses a high-frequency inverter instead of a heavy ballast with a coil wound around an iron core, and can be made smaller and lighter.

Conventionally, such an electronic ballast has a printed circuit board 2 made of paper phenol, glass epoxy, etc., installed at a predetermined interval for insulation on the bottom plate 1a of a housing 1, as shown in FIG. Various circuit components on the printed circuit board 2 3.3. It is known that ... are connected and fixed by soldering.

[Problems to be Solved by the Invention] However, in the case where the printed circuit board 2 is used to connect and fix circuit components, the thickness of the board 2 and the bottom plate 1a
Since there is a predetermined distance φ between the housing 1 and the substrate 2, the bottom of the housing 1 is raised as a whole, which causes the problem that the height of the housing 1 increases and the size of the housing 1 increases.

In addition, components that generate relatively heat such as power transistors, transformers, and choke coils used in high-frequency inverters are mounted on the printed circuit board 2, so heat radiation is insufficient, so the transistors are mounted on heat sinks 4.4 as shown in the figure. For transformers and choke coils, it is necessary to increase the coil diameter to minimize heat generation, use Lindt wire to reduce copper loss, or use high-quality core materials to reduce iron loss. It is necessary to take measures such as reducing the weight, which leads to the problem of increased weight and cost.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an electronic ballast for a discharge lamp that can be made smaller and lighter, and can reduce costs.

Means for Solving the Problem 3 The present invention provides an electronic ballast for a discharge lamp in which various circuit components including a high frequency inverter used for lighting control of a discharge lamp are housed in a metal casing. An insulating layer is laminated on the bottom plate of the insulating layer, a circuit pattern is further laminated on top of the insulating layer, and various circuit components including a high frequency inverter are connected and fixed onto the circuit pattern.

[Function] In the present invention having such a configuration, a circuit pattern is directly laminated on the bottom plate as a metal casing via an insulating layer, and various circuit components are connected and fixed to the circuit pattern. The space between the board and the board and the bottom plate is no longer required, allowing the height of the casing to be lowered. In addition, since the bottom plate directly functions as a heat sink, a heat sink is not required, and heat radiation from transformers, choke coils, etc. can be improved.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, a bottom plate 1 as a metal housing 11
An insulating layer 12 having a thickness of, for example, about 200 μm to 600 μm is laminated on 1a. This insulating layer 12 may be in the form of a sheet or may be coated with an insulating paint.

A circuit pattern 13 made of, for example, copper foil is laminated on the insulating layer 12, and various circuit components 14.degree., including a high frequency inverter, are connected and fixed onto the circuit pattern 13.

FIG. 2 shows the arrangement of actual circuit components that are connected and fixed to the circuit pattern 13 formed on the bottom plate 11a via the insulating layer 12, and FIG. 3 shows the circuit constituted by the circuit components. ing.

A varistor BY that protects the circuit against high voltage is connected between terminals Tl and T2 to which power is supplied, and a capacitor C1 C2 and a coil BT are connected via a current fuse F.
A noise filter consisting of is connected.

Further, an input terminal of a full-wave rectifier diode bridge BG is connected between the terminals TI and T2 via a current fuse F, a noise filter, and a thermal switch TSW.

Between the output terminals of the diode bridge BG are a capacitor C3, a parallel circuit of a resistor R1, a series circuit of a diode D1, a diode D2, a capacitor C4, and a resistor R2.
A parallel circuit and a series circuit are connected. And between the cathode of the diode D1 and the anode of the diode D2, a resistor R3, thermistors TH1, TH2,
A series circuit of diode D3 is connected.

A high frequency inverter IN is connected to the series circuit of the diode D2, the capacitor C4, and the parallel circuit of the resistor R2.

The high frequency inverter IN includes resistors R4 and R5.

R6, R7, Ra, R9, Rt a, Rt 1
, capacitor Cs, diode D4, Ds, D
s, D7.

DB, power transistor Q1. Q2, control transistors Q3 and Q4, a trigger diode TD, and an output transformer TB.

Two fluorescent lamps Ls are connected as discharge lamps between the output terminals of the high frequency inverter IN via a choke coil CH.
, L2 are connected in series. That is, one end of one filament electrode of one fluorescent lamp L1 is connected to the primary winding of the choke coil CH, and also connected to one end of one filament electrode of the other fluorescent lamp L2 via a capacitor C6. The other end of one filament electrode of the lamp L1 is connected to the other end of one filament electrode of the other fluorescent lamp L2 via a capacitor C7.

Also, one end of the other filament electrode of one fluorescent lamp L1 is connected to one end of the other filament electrode of the other fluorescent lamp L1 through the secondary winding of the choke coil C)-1, and The other end of the other filament electrode of L1 is directly connected to the other end of the other filament electrode of the other fluorescent lamp L2.

Further, a capacitor Co is provided between one end of one filament electrode of the other fluorescent lamp L2 and each power supply line of the high frequency inverter IN.

C9 is connected.

Furthermore, a capacitor Cro is connected between one end of one filament electrode and the other end of the other filament electrode of the fluorescent lamp L2.

Each circuit component constituting such a circuit is arranged on the bottom plate 11a in the layout shown in FIG.

In this embodiment having such a configuration, a circuit pattern 13 is formed on the bottom plate 11a via an insulating layer 12, and various circuit components are arranged on the circuit pattern 13 as shown in FIG. Therefore, compared to the conventional case, at least the combined height of the thickness of the board and the distance between the board and the bottom plate can be made lower, so the height of the housing 11 can be reduced by that amount, and miniaturization can be achieved.

Further, a circuit pattern 13 is formed on the synthetic bottom plate 11a with an insulating layer 12 interposed therebetween, and a power transistor Q
1. Since components that generate heat such as Q2, output transformer TB, and choke coil CH are attached, the bottom plate 11a itself functions as a heat sink, and the transistors Qt,
A heat sink is not required for Q2. Also, Idekadrance T
It is possible to eliminate the need for costly and troublesome measures such as increasing the winding diameter of B and choke coil CH, or using litz wire. Therefore, weight reduction and cost reduction can be achieved.

Furthermore, the thickness of the insulating layer 12 is set to 200μ'rrL to 600μ
m, so the circuit pattern 13 and the bottom plate 11a
As a result, leakage current and conduction noise can be sufficiently reduced.

For example, in a product for two 200V 40W fluorescent lamps, aluminum with a thickness of 1 m is used as the bottom plate 11a, on top of which a glass cloth with a thickness of 300 μm is laminated as the insulating layer 12, and on top of that, a glass cloth with a thickness of 35 μm is laminated as the insulating layer 12. By forming a circuit pattern made of copper foil to house the circuit components, the height of the ballast was reduced by about 4 meters compared to the conventional one. Also, when comparing the temperature rise of power transistors, it was about 30 degrees Celsius for those using conventional heat sinks, whereas it was 24 degrees Celsius.
It was found that the heat dissipation effect was excellent, at around ℃. Furthermore, for the choke coil, a single wire was sufficient, whereas the conventional method used a litz wire.

Furthermore, the ferrite core of the choke coil CH is EI30.
The size can be reduced compared to the conventional one using EI40. Furthermore, ordinary materials were sufficient, whereas conventional materials had to be of low loss type.

In addition, the capacitance can be kept low, resulting in a leakage current of 0.7 mA, which is less than the standard value of 1 mA, and conduction noise, at a maximum of 58 dB at frequencies from 450 KHz to 1 MHz, which is less than the standard value. The value 60 (
I was able to make it under 18.

In the above embodiment, a case was described in which two fluorescent lamps were used, but the present invention is not necessarily limited to this, and a lamp for one lamp or a lamp for three or more lamps may be used. Of course, the circuit configuration is different in this case.

[Effects of the Invention] As described in detail above, according to the present invention, it is possible to provide an electronic ballast for a discharge lamp that can be made smaller and lighter, and can reduce costs.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an embodiment of the present invention, Fig. 2 is a diagram showing an example of the arrangement of various circuit components in the same embodiment, Fig. 3 is a circuit diagram of the same embodiment, and Fig. 4 is a conventional example. FIG. DESCRIPTION OF SYMBOLS 11... Housing, 11a... Bottom plate, 12... Insulating layer, 13... Circuit pattern, 14... Circuit component, Q
l. Q2...Power transistor, TB...Output transformer, CH...Choke coil. Applicant's agent Patent attorney Takehiko Suzue

Claims (2)

[Claims] (1) In an electronic ballast for a discharge lamp in which various circuit components including a high-frequency inverter used for lighting control of a discharge lamp are housed in a metal housing, an insulating layer is laminated on the bottom plate serving as the housing, and An electronic ballast for a discharge lamp characterized in that a circuit pattern is further laminated thereon, and various circuit components including a high frequency inverter are connected and fixed on the circuit pattern. (2) The electronic ballast for a discharge lamp according to claim (1), wherein the insulating layer has a thickness of 200 μm or more.