JPS6110958B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a preheating start type discharge lamp lighting device for a plurality of discharge lamps.

FIG. 1 shows an example of a conventional discharge lamp lighting device equipped with a preheating start type lighting circuit. In Figure 1, 1
2 is an AC power supply, and 2 is a full-wave rectifier, the output end of which is connected to a transistor inverter 4 via a constant current reactor 3. The transistor inverter 4 is a pair of transistors 5a and 5b connected in a push-pull manner.
a, 5b, an output transformer 6, a capacitor 7, and starting resistors 8a, 8b.

The output transformer 6 has primary windings 6a, 6b, a feedback winding 6c, a secondary winding 6d, a filament winding 6e,
It is equipped with 6f and 6g. One end of the secondary winding 6d is connected to one filament of the discharge lamps 10a, 10b via the windings 9a, 9b of the balancer 9, respectively, and the other end is connected to each of the other filaments. Further, the filament windings 6e, 6f, 6g are connected to each filament of the discharge lamps 10a, 10b. Note that a, b, c, and d indicate each terminal of the filament windings 6f and 6g.

The discharge lamp lighting device having such a configuration generates a high frequency voltage on the secondary side of the output transformer 6 by alternately switching the transistors 5a and 5b.
This preheats the filament and starts and lights the discharge lamp.

Therefore, when the discharge lamps 10a and 10b are not started, the filament windings 6e to 6g
The voltages Vf ₁ to _{Vf 3} generated in the filament are relatively high, and the filament is appropriately preheated.

However, after the discharge lamps 10a, 10b are turned on, the voltage V ₂ between the terminals of the secondary winding 6d becomes
By lowering the discharge voltage to the discharge voltage b, the filament winding 6 magnetically coupled to the secondary winding 6d
The voltage Vf ₁ to Vf ₃ of e to 6g is applied accordingly at the time of starting.
It drops significantly to about 1/4. In this way, it is possible to prevent the filament of the discharge lamp from overheating during lighting, and to reduce power loss in the filament.

However, in such a circuit, for example, when the discharge lamp 10a is started and lit in advance, the voltage decreases.
Each filament voltage by decreasing _V2
Since Vf ₁ to _{Vf 3} are significantly reduced, the preheating voltage of the discharge lamp 10b that has not yet been lit is insufficient, so the discharge lamp 10b does not light up, or the discharge lamp 10b is half-wave discharged due to insufficient preheating, shortening the life of the discharge lamp 10b. This results in

This invention eliminates the above-mentioned drawbacks and lights a single lamp by providing a balancer with a plurality of auxiliary windings that generate a voltage that is added to the output voltage of the filament heating power supply in a preheating start type lighting circuit. It is an object of the present invention to provide a discharge lamp lighting device that can perform sufficient preheating at the time of starting even after the lamp is started, ensures reliable lighting, and can extend its life.

An embodiment of the present invention will be described below with reference to the drawings.

In Fig. 2, 11 is an AC power supply, 12 is a full-wave rectifier, and the output terminal is also a constant current reactor 1.
3 to the transistor inverter 14. This transistor inverter 14 generates a power supply voltage for lighting the discharge lamp and a power supply voltage for heating the filament, and is connected to a pair of transistors 15.
a, 15b, an output transformer 16, a capacitor 17, and starting resistors 18a, 18b. That is, the positive output terminal of the full-wave rectifier 12 is connected to the common connection point of the primary windings 16a and 16b of the output transformer 16, the other ends of each are connected to the collectors of the transistors 15a and 15b, and the emitters are connected together. Connect to one end of constant current reactor 13. The bases of transistors 15a and 15b are connected to the positive output terminal of full-wave rectifier 12 via starting resistors 18a and 18b, respectively, and the ends of feedback winding 16c of output transformer 16 are connected to the bases of transistors 15a and 15b, respectively. do.

The output transformer 16 also includes a secondary winding 16d and filament windings 16e, 16f, and 16g.

One end of the secondary winding 16d is connected to the winding 1 of the balancer 19.
Discharge lamps 20a and 2 via 9a and 19b, respectively.
Auxiliary windings 19c and 19d are connected to one end of one filament of filament 0b, and auxiliary windings 19c and 19d are provided which are extensions of windings 19a and 19b. Connect to. In addition, auxiliary windings 19e and 19 are separately provided in the balancer 19 with a common connection point between the secondary winding 16d and the filament winding 16e.
It is connected to one end of each of the other filaments of the discharge lamps 20a and 20b through f, respectively, and the other ends thereof are collectively connected to the other end of the filament winding 16e. Note that the auxiliary windings 19c, 19d and 19
The windings e and 19f are wound in such a direction that the voltage generated therein is added to the voltage of the filament windings 16e, 16f and 16g.

Also in this discharge lamp lighting device, a high frequency voltage is generated on the secondary side of the output transformer 16 by alternately switching the transistors 15a and 15b.
This heats the filament and starts and lights the discharge lamp.

At this time, if we consider a case where the discharge lamp 20a is started and lit in advance, the filament windings 16e~
The output voltages Vf ₁ to _{Vf 3} of 16g are significantly lower than before starting, as in the case of the conventional example, and it becomes difficult to perform sufficient preheating.

However, due to the discharge current flowing through the discharge lamp 20a, the auxiliary windings 19f, 19 of the balancer 19
At d, a polar voltage is generated which is added to the output voltages Vf ₁ and Vf ₃ of the filament windings 16e and 16g, and the preheating voltage of the discharge lamp 20b increases, so that the discharge lamp 20b can be reliably started and lit.

Therefore, it is possible to avoid a situation in which the discharge lamp 20b does not light up or lights up in a half-wave.
Shortening of the life of the discharge lamp 20b can be suppressed.

After the discharge lamps 20a and 20b are both started and lit, balance is maintained and the magnetic flux of the balancer 19 becomes 0.
Therefore, the voltage applied to the filaments of the discharge lamps 20a and 20b is the voltage Vf ₁ to Vf ₃ of the filament windings 16e to 16g during lighting. Therefore, each filament is not overheated, and filament loss can be reduced.

Next, FIG. 3 shows a different embodiment of the present invention. In this embodiment, a parallel circuit consisting of a light control coil 21 and a switch 22 is inserted between one end of the secondary winding 16d of the output transformer 16 and the balancer 19, and the light is controlled by opening and closing the switch 22. In Figure 3, other parts are
Since it is similar to the figure, the same parts are given the same reference numerals and the explanation will be omitted.

Even if the discharge lamps 20a and 20b are both turned on with the dimming coil 21 inserted into the circuit, there is a voltage drop across the dimming coil 21, so the output voltage _V2 of the secondary winding 16d is lower than the filament. The output voltage of windings 16e-16g does not drop significantly. For this reason, in order to prevent the filament from overheating when the discharge lamp is turned on, it is actually necessary to set the filament voltage low in advance, and if one discharge lamp 20a is started and turned on in advance,
There is a great possibility that the other discharge lamp 20b will not light up or will have a half-wave discharge, which will shorten its life. However, in this embodiment, the auxiliary windings 19c, 19
Since the voltage generated at e or 19d and 19f can be sufficiently compensated for, this concern can be eliminated. In particular, the present invention can be applied to the embodiment shown in FIG. 3 to further exhibit its effects.

Although the embodiment shown in FIG. 3 is one in which two discharge lamps are connected in parallel, the number of discharge lamps in this invention can be increased as necessary. Figure 4 shows an example in which this is configured for three lamps, and a fifth lamp.
The figure shows an implementation in which this is configured for four lights.

In the embodiment of FIG. 4, a filament winding 16h of the output transformer 16 is provided for the third discharge lamp 10c, and a winding 19a' is provided to balance the operation between the discharge lamps 10a, 10b and 10c. ,19
b', and a second balancer 19' having auxiliary windings 19d' and 19f'.

The embodiment of FIG. 5 shows the third and fourth discharge lamps 10.
filament windings 16h and 16i are provided in the output transformer 16 for the discharge lamps 10c and 10d, and windings 19a'', 19b'' and auxiliary windings 19c'' to 19f are provided to balance the operation between the discharge lamps 10c and 10d. balancer 19'' with
A balancer 19' having windings 19a' and 19b' is provided to balance the operations between 0b, 10c, and 10d.

In these embodiments, as in each of the above-described embodiments, when one of the plurality of discharge lamps is lit, the filaments of the other discharge lamps are sufficiently preheated by the action of each auxiliary winding, and the other discharge lamps are easily lit. It is something that can be done.

Also, if you have multiple discharge lamps, for example one is 40W and the other is
When discharge lamps with different ratings, such as 32W, are used, only one lamp is often turned on first, and the present invention is particularly effective in such cases.

Note that the present invention is not limited to the above-mentioned embodiments, and can be implemented with various modifications without changing the gist. For example, in the above embodiment, an inverter is used to generate the voltage for lighting the discharge lamp and the voltage for preheating the filament, but the present invention is not necessarily limited to this, and other suitable power supply devices may be used. can do.

As described above, according to the present invention, in a preheating start type lighting circuit, the balancer is provided with a plurality of auxiliary windings that generate a voltage in the direction in which the filament is added to the output voltage of the heating power source. It is possible to provide a discharge lamp lighting device that can perform sufficient preheating at the time of starting even when the lamp is lit, ensures reliable lighting, and extends its life.

[Brief explanation of the drawing]

FIG. 1 is a circuit configuration diagram of an example of a conventional discharge lamp lighting device, and FIGS. 2 to 5 are circuit configuration diagrams showing different embodiments of the present invention. 1... AC power supply, 2... Full wave rectifier, 3... Constant current reactor, 4... Transistor inverter, 5a, 5b... Transistor, 6... Output transformer, 6a, 6b... Primary winding, 6c ...Feedback winding, 6d...Secondary winding, 6e to 6g...Filament winding, 7...Capacitor, 8a, 8b...
Starting resistor, 9... Balancer, 9a, 9b... Winding, 10a, 10b... Discharge lamp, 11... AC power supply, 12... Full wave rectifier, 13... Constant current reactor, 14... Transistor inverter, 15
a, 15b...transistor, 16...output transformer, 16a, 16b...primary winding, 16c...
Feedback winding, 16d...Secondary winding, 16e to 16g
...Filament winding, 17...Capacitor, 1
8a, 18b... Starting resistance, 19... Balancer,
19a, 19b...Winding, 19c-19f...Auxiliary winding, 20a-20b...Discharge lamp, 21...Dimmer control coil, 22...Switch.

Claims (1)

[Scope of Claims] 1. A lighting power source, a filament heating power source whose voltage changes in accordance with the voltage change of the lighting power source, and a filament heating power source that is energized by the lighting power source and heats the filament. a plurality of parallel-connected discharge lamps energized by the lighting power source and a balancer provided between the lighting power source and the plurality of discharge lamps to balance the operation of the discharge lamps; A discharge lamp lighting device characterized in that the balancer is provided with a plurality of auxiliary windings that generate a voltage in a direction that is added to the output voltage of the filament heating power source and apply it to the discharge lamp before starting. 2. The discharge lamp lighting device according to claim 1, further comprising a dimming coil that is inserted and removed by a switch between the lighting power source and the balancer.