JP2002222698A - Discharge lamp drive circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make preheating of a filament with a structure having a minimum number of wirings with power supply circuit side. SOLUTION: A primary circuit 15 includes a capacitor 12 connected in series between a first filament F1 of a first discharge lamp 10 and a first filament F3 of a second discharge lamp 11 and a primary winding 13 of a flow splitting transformer T and power is supplied between one end of each first filament F1, F3 of the first and the second discharge lamps. A second circuit 16 is a secondary winding 14 of the flow splitting transformer T connected in series with a second filament F2 of the first discharge lamp 10 and a second filament F4 of the second discharge lamp 11. When power is supplied to the primary circuit 15 at light start-up, current flows also into the secondary circuit 16, and all the filaments are preheated, which dispenses with particular wiring for preheating.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving circuit for an ultraviolet discharge lamp, a fluorescent lamp, and other discharge lamps used in an ultraviolet disinfection device or a sterilization device, and more particularly, to two discharge lamps using a common power supply circuit. The present invention relates to a control type discharge lamp driving circuit.

[0002]

2. Description of the Related Art In an ultraviolet discharge lamp device of a type in which a common power supply circuit 20 controls two discharge lamps 10 and 11, when a filament is preheated, typically, as shown in FIG. Each filament is connected to the secondary side of the preheating transformer 26 on the power supply circuit 20 side. Therefore, the discharge lamps 10 and 11 and the power supply circuit 20
The total number of wirings in the wiring unit 30 connecting the two is as large as six. The power supply circuit 20 includes, for example, a DC converter 22 that converts a power supply from a commercial AC power supply 21 into a DC voltage.
An inverter circuit 23 for converting the DC voltage into a predetermined high-frequency voltage; a choke coil 24 and a capacitor 2
5 and a series resonance circuit. As described above, the series resonance circuit including the choke coil 24 and the capacitor 25 is provided on the power supply circuit 20 side.
0 and 11 are applied. Therefore, the current flowing through the series resonance circuit does not contribute to the preheating of the filament.

[0003]

As described above, in the conventional device, since the number of wires in the wiring portion 30 is six, the configuration is complicated and the cost is high. In particular, in general, in an ultraviolet disinfection device or a sterilization device, the power supply circuit 20 is disposed on the side of the control panel separated from the ultraviolet discharge lamps 10 and 11, so that the wiring portion 30 therebetween is relatively long. Therefore, it is not preferable that the number of wirings be increased.
Also, a preheating transformer 26 must be provided on the power supply circuit 20 side, which is disadvantageous in this respect as well. In addition, since the potential relationship between the filaments is uncertain, the starting point of the discharge on the filament is uncertain, and the lamp life often ends before the discharge material of the filament is completely used up.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and in a two-lamp type discharge lamp driving circuit, it is possible to preheat a filament with a configuration in which the number of wires to the power supply circuit side is minimized. Is to try. Another object of the present invention is to provide a discharge lamp driving circuit capable of extending the lamp life by efficiently using the filament.

[0005]

SUMMARY OF THE INVENTION A discharge lamp driving circuit according to the present invention comprises first and second discharge lamps each including a pair of discharge filaments.
And a capacitor connected in series between a first filament of the first discharge lamp and a first filament of the second discharge lamp for driving a second discharge lamp. A primary winding of a diversion transformer, wherein power is applied between one end of the first filament of the first discharge lamp and one end of the first filament of the second discharge lamp. The first circuit is connected to a secondary circuit and a secondary winding of the shunt transformer.
And a secondary circuit in which the second filament of the second discharge lamp is connected in series.

As a result, the power supply from the power supply circuit becomes 1
A first filament of the first discharge lamp is applied between one end of the first filament of the first discharge lamp and one end of the first filament of the second discharge lamp in the next circuit. A current flows in a primary circuit in which a capacitor, a primary winding of a shunt transformer, and a first filament of a second discharge lamp are connected in series, and each first filament is preheated. At the same time, current flows through a secondary winding of the shunt transformer to a secondary circuit formed by connecting the second filament of the first discharge lamp and the second filament of the second discharge lamp in series, Each second filament is preheated.
In this way, since all the filaments are preheated, sputtering at the time of starting the lighting can be suppressed by the filament preheating effect, and the lamp life can be extended. The number of wires to the power supply circuit side is only two wires applied to the primary circuit, and the configuration can be simplified with a minimum number of wires.

The connection of the first and second discharge lamps to the first filament on the primary circuit side corresponds to the second and third discharge lamps of the first and second discharge lamps in the secondary circuit.
The connection to the filaments is preferably reversed. Thereby, in each of the first and second discharge lamps, the electric potential of the first filament can be ensured to be higher than the electric potential of the second filament. The discharge always occurs from the portion to the end of the second filament, and efficient discharge can be realized.

[0008] In each of the first filaments of the first and second discharge lamps, it is preferable to further comprise an AC current bypass capacitor for each filament, which bypasses between one end and the other end of the filament. This allows
The current flowing directly to each filament can be suppressed, and the life of the filament can be further extended.

[0009]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 shows an embodiment of a discharge lamp driving circuit according to the present invention. In each of first and second discharge lamps 10 and 11 including a pair of discharge filaments F1, F2, F3 and F4, respectively. The first filament F1 of the first discharge lamp 10 and the second discharge lamp 11
A primary circuit 15 is formed between the first filament F3 and the capacitor 12 and the primary winding 13 of the shunt transformer T in series. One end of the first filament F1 of the first discharge lamp 10 and the first end of the second discharge lamp 11
Is connected to the power supply circuit 20 via the wiring section 30. The second filament F2 of the first discharge lamp 10 is connected to the secondary winding 14 of the shunt transformer T.
The secondary circuit 16 is formed by connecting the second filament F4 of the second discharge lamp 11 in series in a loop.

A power supply circuit 20 includes a DC converter 22 for converting a power supply from a commercial AC power supply 21 into a DC voltage, and an inverter circuit 23 for converting the DC voltage into a predetermined high-frequency voltage. , A choke coil 24. The capacitor forming a series resonance circuit together with the choke coil 24 is the capacitor 1 on the side of the discharge lamps 10 and 11.
2 does not need to be provided on the power supply circuit 20 side. The wiring section 30 connecting the power supply circuit 20 and the discharge lamps 10 and 11 has only two wires.

With this configuration, a power switch (not shown) provided on the side of the power supply circuit 20 is turned on to turn on the discharge lamp 1.
At the time of starting the lighting for starting the power supply to the capacitors 0 and 11, the capacitor 12 and the primary winding 1 of the shunt transformer T are turned on.
The current flows through the primary filaments F1 and F3 of the first and second discharge lamps 10 and 11 via the primary circuit 15 including An induced voltage is generated, and a current flows through the secondary circuit 16 to the second filaments F2 and F4 of the first and second discharge lamps 10 and 11. In this manner, all filaments are preheated based on the current flowing through the series resonance circuit including the choke coil 24 and the capacitor 12, and the filament preheating effect can suppress sputtering at the start of lighting. When the potential difference between the filaments in each of the discharge lamps 10 and 11 reaches a predetermined discharge start voltage, discharge starts.

The first and second discharge lamps 1 on the primary circuit 15 side
Connection of 0,11 to the first filaments F1, F3
The first and second discharges in the secondary circuit 16
For the second filaments F2, F4 of the lamps 10, 11
The connection of the secondary circuit 16 is configured so that the connection is in opposite phase.
Have been. The first filament F1 of the first discharge lamp 10
The potential at one end near the power supply circuit 20 of H₀Represented by
Power supply to the first filament F3 of the second discharge lamp 11
The potential at one end near the circuit 20 is set to H_Five, Primary winding of transformer T
The potential of the end of the line 13 near the first discharge lamp 10 is H,
The potential of the end of the next winding 13 near the second discharge lamp 11 is L,
When expressed as₀> H_FiveAt the time of H₀> H> L> H_FiveRelationship
Becomes In addition, the primary in the secondary winding 14 of the transformer T
The potential at the end corresponding to H of the winding 13 is H₁Expressed as
Due to the above-described reversed-phase connection, the second discharge lamp 11 has a second filter.
The potential of the end of the filament F4 near the secondary winding 14 is the same H
₁It is. Also, 1 in the secondary winding 14 of the transformer T
The potential at the end corresponding to L of the next winding 13 is H_FourRepresented by
And the second connection of the first discharge lamp 10
The potential of the end of the filament F2 near the secondary winding 14 is the same.
H_FourIt is. Second filament of second discharge lamp 11
H of F4₁The potential at the end opposite to_TwoRepresented by
The above H of the second filament F2 of the first discharge lamp 10_Four
The potential at the end opposite to_ThreeExpressed as, H₁> H_Four
At the time of H₁> H_Two> H_Three> H_FourRelationship. In addition,
The number of primary and secondary windings of the lance T is the primary winding number
Is big.

Thus, at the start of discharge, H ₀ >
If H ₅ , H ₀ is the highest potential, H ₅ is the lowest potential,
In the first discharge lamp 10, H ₀ > H ₃ > H ₄ is satisfied, and from the highest potential H _{0 at} one end of the first filament F 1 to the lowest potential H ₄ at the other end of the second filament F 2. Discharge occurs toward the end. At the same time, the second discharge lamp 1
Holds is H _1> H _2> H ₅ in 1, discharge occurs from the point of highest potential H ₁ of one end of the second filament F4 toward the point of lowest potential H ₅ at the other end of the first filament F3 . As described above, since the discharge can be reliably started from the end of each filament, the discharge material of the filament can be efficiently used up from the end without waste, and the lamp life can be extended. .

FIG. 2 shows another embodiment of the present invention. FIG.
Is basically the same as the embodiment of FIG.
Each first filament F1, F included in the primary circuit 15
Every three bypasses between one end and the other end of the filament,
Only the point that the AC current bypass capacitors C1 and C2 are provided for each of the first filaments F1 and F3 is shown in FIG.
And different. Thus, each first filament F1, F1
By providing the AC current bypass capacitors C1 and C2 for each of the three filaments, the first filament F
1, the current flowing directly to F3 can be suppressed, and the life of the filament can be further extended. A similar AC current bypass capacitor is connected to the second filament F2.
You may make it provide also in F4.

Since the capacitors 12, C1, C2 and transformer T provided on the side of the discharge lamps 10 and 11 only need to have a small capacity, they can be arranged in the base of the discharge lamp or in the socket to make the whole apparatus compact. can do. In the above embodiment, the types of the discharge lamps 10 and 11 are, for example, an ultraviolet discharge lamp or a fluorescent lamp, and may be any type of discharge lamp depending on the application.

[0016]

As described above, according to the present invention, the capacitor of the series resonance circuit is disposed on the discharge lamp side, and the first filament of the first discharge lamp, the capacitor, and the primary winding of the shunt transformer. The current of the series resonance circuit is caused to flow in the primary circuit formed by connecting the first filament of the second discharge lamp in series, and the current of the secondary winding of the shunt transformer is changed to the first and second currents. Since it is made to flow to the second filament of the discharge lamp, the preheating of all the filaments can be performed only by providing only two power supply wires without connecting a special preheating wire to the power supply circuit. It is possible to extend the life of the lamp by suppressing the sputtering at the time of starting by the filament preheating effect, and to realize it with the minimum number of wires. It can be. Further, the connection of the first and second discharge lamps to the first filament in the secondary circuit is different from the connection of the first and second discharge lamps to the second filament in the secondary circuit. Are connected in opposite phases to ensure that the potential of the first filament is higher than the potential of the second filament in each of the first and second discharge lamps. As a result, the discharge is always performed from the end of the first filament to the end of the second filament, and efficient discharge can be realized. Furthermore, the first
And in each of the first filaments of the second discharge lamp, bypassing between one end and the other end of the filament,
By further providing an AC current bypass capacitor for each filament, the current flowing directly to each filament can be suppressed, and the life of the filament can be further extended.

[Brief description of the drawings]

FIG. 1 is a schematic circuit diagram showing one embodiment of a discharge lamp driving circuit according to the present invention.

FIG. 2 is a schematic circuit diagram showing another embodiment of the discharge lamp driving circuit according to the present invention.

FIG. 3 is a schematic circuit diagram showing an example of a conventional two-lamp discharge lamp driving circuit.

[Explanation of symbols]

 10, 11 Discharge lamp F1, F2, F3, F4 Discharge filament 20 Power supply circuit 30 Wiring unit 12 Capacitor T transformer 13 Primary winding 14 Secondary winding 15 Primary circuit 16 Secondary circuit C1, C2 AC current bypass Capacitors

Claims (4)

[Claims] 1. A discharge lamp driving circuit for driving first and second discharge lamps each including a pair of discharge filaments, wherein a first filament of the first discharge lamp and a second discharge lamp are provided. And a primary winding of a shunt transformer connected in series between the first filament of the discharge lamp and the first filament.
A primary circuit in which power is applied between one end of the first filament of the discharge lamp and one end of the first filament of the second discharge lamp, and a secondary winding of the shunt transformer. A discharge lamp driving circuit comprising: a second filament of the first discharge lamp; and a secondary circuit formed by connecting a second filament of the second discharge lamp in series. 2. The discharge lamp driving circuit according to claim 1, wherein the capacitor forms a series resonance circuit together with a coil provided on a power supply circuit side. 3. The connection of the first and second discharge lamps on the primary circuit side to the first filament,
3. The discharge lamp driving circuit according to claim 1, wherein the connection of the first and second discharge lamps to the second filament in the secondary circuit is connected in an opposite phase. 4. 4. An AC current bypass capacitor for each of the first filaments of each of the first and second discharge lamps, the capacitor bypassing between one end and the other end of the filament. Item 4. The discharge lamp driving circuit according to any one of Items 1 to 3.