JP3812066B2 - lighting equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lighting fixture .
[0002]
[Prior art]
A schematic plan view according to the present invention is shown in FIG. 2, and a circuit diagram is shown in FIG.
[0003]
The schematic plan view shown in FIG. 2 shows a lighting fixture for two lamps of a discharge lamp (hereinafter referred to as a lamp), a fixture main body 1, a lamp La1 having lamp sockets 3 and 5, and a lamp socket. 4 and 6, an electronic ballast 2 for lighting the lamps La1 and La2, and lead wires L1 to L7 connecting the lamps La1 and La2 and the electronic ballast 2, and the lamps La1 and La2 The ballast 2 and the lead wires L1 to L7 are accommodated in the instrument main body 1.
[0004]
FIG. 3 shows a circuit diagram of a discharge lamp lighting device composed of the lamps La1 and La2, the electronic ballast 2, and the lead wires L1 to L7, and its configuration is shown below.
[0005]
Connected to both ends of the AC power supply E, the AC power supply E, a filter circuit F including a capacitor C4 and an inductor L3, a rectifier DB for rectifying the AC power supply E via the filter circuit F, and an output terminal of the rectifier DB A smoothing capacitor C2 that smoothes the DC voltage output of the rectifier DB, an inverter circuit that is connected to the output terminal of the rectifier DB, converts the voltage across the smoothing capacitor C2 into a high-frequency voltage, and supplies the high-frequency voltage to the load circuit; And a capacitor C1 connected to the output terminal of DB. Here, the inverter circuit is a so-called half-bridge inverter circuit composed of a series circuit of field effect transistors (hereinafter referred to as switching elements) Q1 and Q2, and the switching elements Q1 and Q2 are alternately turned on and off by the control circuit 10. By repeating the above, the lamps La1 and La2 that are loads are turned on at a high frequency. The load circuit includes a series circuit of a capacitor C4 connected to both ends of the switching element Q2 and a primary winding n1 of the leakage transformer T1, and a secondary of the leakage transformer T1 through lead wires L2, L3, L5, and L6. Lamps La1 and La2 connected in series on the side, and a capacitor C3 connected to both ends of a series circuit of the lamps La1 and La2 via lead wires L1 and L4. Further, a series resonance circuit is constituted by the leakage inductance of the leakage transformer T1 and the capacitor C3. The capacitor C4 is a DC component cutting capacitor, and has a sufficiently larger capacitance value than the capacitor C3.
[0006]
Then, the current of the capacitor C3 flows through the path of the secondary winding n2 of the leakage transformer T1, the filament f1, the capacitor C3, the filament f4, and the secondary winding n2 of the leakage transformer T1, thereby preheating the filament f1 and the filament f4. The filament f2 and the filament f3 are preheated when a current flows through the path of the secondary winding n3 of the leakage transformer T1, the filament f2, the filament f3, and the secondary winding n3 of the leakage transformer T1. By sufficiently preheating each filament before applying a high voltage across the lamps La1 and La2, the transition from starting to lighting is facilitated.
[0007]
[Problems to be solved by the invention]
However, in the above conventional example, when the lamp La1 is removed while the lamp is lit, both the lamps La1 and La2 are inconsequential. However, if the filament f2 is removed before the filament f1, the leakage inductance of the leakage transformer T1 is reduced. Since the series resonance circuit with the capacitor C3 remains configured, an excessive current flowing in the resonance circuit flows in the switching elements Q1, Q2, etc., and a large stress is generated in the switching elements Q1, Q2, etc. Dots will occur.
[0008]
The present invention has been made in view of the above problems, and its object is to prevent large stress from being generated in the switching elements Q1, Q2, etc. even when the lamp is removed while the lamp is lit. It is to provide a reliable luminaire .
[0009]
[Means for Solving the Problems]
In order to solve the above problems, according to the first aspect of the present invention, an inverter circuit that converts a DC voltage into a high-frequency voltage, a series circuit of a plurality of discharge lamps that are supplied with the high-frequency voltage of the inverter circuit, A discharge lamp lighting device comprising: a resonance circuit connected to the output terminal of the inverter circuit via one filament of the discharge lamp; and a closed circuit formed via the other filament of each discharge lamp . A socket cover that covers all the filaments forming a closed circuit of the discharge lamp is provided, and when the discharge lamp is removed, the filament connected to the resonance circuit is removed first.
[0011]
According to invention of Claim 2 , a closed circuit forms the preheating circuit of a discharge lamp, It is characterized by the above-mentioned.
[0012]
According to a third aspect of the present invention, the resonant circuit forms a preheating circuit for a discharge lamp.
[0013]
Embodiment
FIG. 1 shows a schematic plan view of an embodiment according to the present invention.
[0014]
2 differs from the conventional example shown in FIG. 2 in that a lamp socket cover 7 is provided to cover the lamp sockets 5 and 6, and when the lamp is removed while the lamp is on, the leakage inductance of the leakage transformer T1 and the capacitor C3 are connected in series. This is configured to be removed from the side of the filament forming the resonance circuit (here, the filaments f1 and f4 shown in FIG. 3). To do.
[0015]
With this configuration, in any case where the lamp is removed while the lamp is lit, the series resonant circuit side by the leakage inductance of the leakage transformer T1 and the capacitor C3 is removed first, so that the switching elements Q1, Q2, etc. It is possible to prevent large stress from occurring.
[0016]
Although the number of lamps is two, the number of lamps may be any number, and the inverter circuit may have any configuration.
[0017]
【The invention's effect】
According to the first to third aspects of the present invention, there is provided a highly reliable lighting apparatus that prevents a large stress from being generated in the switching elements Q1, Q2, etc. even when the lamp is removed while the lamp is on. Can be provided.
[Brief description of the drawings]
FIG. 1 is a schematic plan view of an embodiment according to the present invention.
FIG. 2 is a schematic plan view of a conventional example according to the present invention.
FIG. 3 shows a circuit diagram according to the invention.
[Explanation of symbols]
f Filament La discharge lamp

Claims (3)

An inverter circuit for converting a DC voltage into a high frequency voltage, a series circuit of a plurality of discharge lamps to which the high frequency voltage of the inverter circuit is supplied, and an output terminal of the inverter circuit via one filament of each of the discharge lamps In a discharge lamp lighting device comprising a connected resonant circuit and a closed circuit formed via the other filament of each of the discharge lamps, all the filaments forming the closed circuit of the plurality of discharge lamps A lighting fixture , wherein a socket cover is provided, and the filament connected to the resonance circuit is removed first when the discharge lamp is removed. The lighting apparatus according to claim 1 , wherein the closed circuit forms a preheating circuit of the discharge lamp . The lighting apparatus according to claim 1 , wherein the resonance circuit forms a preheating circuit of the discharge lamp.

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