JPS617599A - Device for firing discharge lamp - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a discharge lamp lighting device capable of lighting a discharge lamp such as a fluorescent lamp and performing stepwise dimming of the discharge lamp.

[Background technology]

FIG. 5 shows a conventional discharge lamp lighting device, in which a commercial power source 1 is converted to direct current through a power switch 14 by a rectifying bridge 2 and a capacitor 4, a transistor 7.8, resistors 5, 6 . React 3. The oscillation transformer 1 drives an inverter device IN composed of a capacitor 99, an oscillation transformer 10, etc.
A discharge lamp 13 is connected to the secondary winding N2 of No. 0 through a parallel circuit of a dimmer reactor 11 and a dimmer switch 12. N1 is the primary winding of the oscillation transformer 10.

In this discharge lamp lighting device, when the dimmer switch 12 is closed, the dimmer reactor 11 is short-circuited and the discharge lamp 13 is fully lit, and when the dimmer switch 12 is opened, the current is limited by the dimmer reactor 11 and the discharge lamp 13 is dimmed and lit.

Now, if the dimmer switch 12 is opened in a fully lit state with the dimmer switch 12 closed and the dimmer reactor 11 short-circuited, an arc discharge will occur at the contacts of the dimmer switch 12, and this arc discharge is caused by high frequency. It has the property of being difficult to extinguish. Therefore, as the arc discharge continues, the contacts of the dimmer switch 12 may heat up and disappear.

As a first measure to prevent this phenomenon, a method has been proposed in which the power switch 14 is opened immediately before or at the same time as the dimmer switch 12 is opened to cut off the input and temporarily stop or reduce the inverter output. There is.

FIG. 6 shows another conventional example that can prevent damage to the contacts of the dimmer switch 12, in which the secondary winding N of the oscillation transformer 10'
A series circuit of a voltage reduction auxiliary winding N3 and a switch 14' is provided in parallel with the dimmer switch 12, and the switch 14' is temporarily turned on immediately before or at the same time as the dimmer switch 12 is opened to set the load short-circuited. This is an example in which arcing at 12 contacts is prevented (15 is a low impedance circuit such as a preheating transformer). In this case, the auxiliary winding N3 for voltage reduction is
This is to prevent arcing when the switch 14' is opened and closed, but it is also conceivable to provide an intermediate tap in the secondary winding N2 instead of the voltage reducing auxiliary winding N3.

In addition to mechanical contacts, a non-contact switch such as a saturable reactor may be used as the switch 14'.

By using such a conventional example, the contacts of the dimmer switch 12 are protected, but in any case, in order to reduce the in-hark output and bring the discharge lamp to a state close to extinguishment, it is necessary to switch from full lighting to dimmed lighting. When switching, there was a risk of giving an unnatural feeling.

[Purpose of the invention]

An object of the present invention is to provide a discharge lamp lighting device that can reliably prevent damage to a dimmer switch when switching from a full lighting state to a dimmed lighting state and can perform smooth switching.

[Disclosure of the invention]

The discharge lamp lighting device of the present invention includes a contact dimmer switch that is inserted in a power supply path to the discharge lamp to fully light the discharge lamp when the lamp is opened and to control the dimming of the discharge lamp when the lamp is opened; A saturable reactor connected in parallel to a dimmer switch, a DC power supply that flows an excitation current to the saturable rear and lid, and a switch inserted between the saturable reactor and the DC power supply, and the dimmer switch It is characterized in that the switch is closed immediately before or at the same time as the dimmer switch is opened, and the switch is opened after the dimmer switch is opened.

DESCRIPTION OF THE EMBODIMENTS A first embodiment of the present invention will be described based on FIGS. 1 and 2. This discharge lamp lighting device, as shown in Fig.
Convert to DC, transistor 7°8, resistor 5, 6 . Reactor 3. An inverter device IN consisting of a capacitor 91, an oscillation transformer 10, etc. is driven, and a discharge lamp 13 is connected to the secondary winding N2 side of the oscillation transformer 10 through a parallel circuit of a dimmer reactor 11 and a dimmer switch (contact) 12. A saturable reactor 15 is also connected in parallel with the dimmer switch 12.
is connected. The excitation coil of this saturable reactor 15 is connected to a DC power source 17 via a switch 16.

In such a configuration, when the dimmer switch 12 is opened with the dimmer switch 12 closed and fully lit, the switch 16 of the DC power supply 17 is turned on immediately before or at the latest at the same time to turn on the saturable reactor. 15 is short-circuited.

If the opening operation of the dimmer switch 12 is completed in the meantime, and then the switch 15 of the DC power supply 17 is opened, the reactance of the saturable reactor 15 becomes a large value compared to fluorine, so that the dimmer reactor 11 A limited tube current flows and the light is dimmed.

Figure 2 shows the dimmer switch 12 at this time. A time chart of the on/off state of the switch 15 and the lighting state of the discharge lamp 13 is shown. To explain Figure 2, Figure 2 (B
), the switch 16 is switched from off to on (switching start) at time 1 (,), and at time t1, when the switch 16 is on, the dimmer switch 12 is switched from on to off as shown in Figure 2 (A). At time t2 after the dimmer switch 12 is turned off, the switch 16 is turned off again (switching completed) as shown in FIG. 2 (CB). As a result, the discharge lamp 1,
3 continues in the full lighting state until time t2 as shown in FIG. 2(C), and switches to the dimming lighting state at this time t2.

Here, assuming that the dimmer switch 12 and the switch 15 are, for example, interlocked mechanical contacts, it is easy to mechanically obtain the timing as shown in FIG. 2. That is, the seventh
As shown in the figure, the dimmer switch 12 and the switch 16 may be configured as sliding type low-return switches. Furthermore, assuming that the dimmer switch 12 is a relay contact, a monostable multi-high break is used that first turns on the switch 16 for a predetermined period of time using a switching signal, and then a monostable multi-high break is used that drives the relay while the monostable multi-high break is in operation. It is also easy to add a control circuit. In this case, the ON time of the switch 16 may be set to the time until the dimmer switch 12 is completely switched.

As described above, in this embodiment, when switching the dimmer switch 12 from on to off to switch from a full lighting state to a dimmed lighting state, the switch 16 is turned on immediately before or at the same time as the dimmer switch 12 is opened. to make the saturable reactor 15 conductive, and in the state where the saturable reactor 15 is conductive, the dimmer switch 12 is turned off, and after the dimmer switch 12 is turned off, the switch 16 is turned off to make the saturable reactor 15 high impedance. Therefore, switching from the full lighting state to the dimming lighting state is performed by the saturable reactor 15, and the dimmer switch 15 merely functions to maintain the full lighting state and the dimming lighting state. No contact arc occurs, and the dimmer switch 12 can be protected.

Furthermore, the discharge lamp 13 is not turned off when switching from the full lighting state to the dimming lighting state, and the switching from full lighting to dimming lighting can be performed smoothly.

In addition, without using a non-contact element as the dimmer switch 12,
The reason why the contact dimmer switch 12 and the saturable reactor 15 are used is to prevent the following problems from occurring. That is, if a non-contact element is used as the dimmer switch 12, the problem of contact arcing will not occur. However, if Cyrisk is used as the dimmer switch 12, it is difficult to turn off due to the high frequency and it does not have a switch function, and if a high voltage transistor is used, a high voltage is applied during dimming and the switch is turned off. If the transistor is left unused for a long time, the leakage current of the transistor increases and there is a risk of thermal runaway.

Furthermore, when a saturable reactor is used as the dimmer switch 12, it must be kept in a short-circuited state during full lighting, and saturation of the iron core must not occur even at the high voltage applied during dimming. That is, the iron core is usually designed to have a structure in which no gap is provided in order to improve the saturation characteristics caused by the excitation current, but the iron core becomes large in order to avoid saturation caused by the high voltage during dimming. Along with this, the excitation ampere turns also increase, and the number of turns of the excitation coil becomes very large. If the excitation current continues to flow through a saturable reactor designed in this way when all the lights are on, the excitation coil will generate a large amount of heat (copper loss), leading to a decrease in circuit efficiency and reliability. It has the disadvantage of being expensive.

A second embodiment of the invention will be described based on FIG.

This discharge lamp lighting device uses the saturable reactor 15 in FIG.
The opening/closing timing is the same as that in FIG. However, it is necessary to design the inductance of the saturable reactor 15 to be equal to the inductance of the dimming reactor in FIG. 1 when the switch 16 is opened to stop excitation.

This embodiment has the same effect as the first embodiment, and also
The number of parts can be reduced, resulting in smaller size and lower costs.

A third embodiment of the invention will be described based on FIG. 4.

This discharge lamp lighting device has a secondary winding N of an oscillation transformer 10.
By switching the taps No. 2 with the dimmer switch 12', you can switch between full lighting and dimmed lighting. When the light switch/door switch 12' is switched to the switching terminal side (low voltage side), the light is dimmerly lit, and the actuator 15 is saturable between the dimmer switch 12' switching terminal a and the common terminal C. The excitation coil is connected to a DC power source 17 via a switch 16.

When switching the dimmer switch 12' from the a side to the b side (all lights on - dimmed lighting), the switch 16 is turned on immediately before or at the same time as switching, the saturable reactor 15 is excited and saturated, and the dimmer switch After completing the switching of 12', switch 1
6 is turned off.

In this embodiment as well, it is possible to prevent contact arcing of the dimmer switch 12' as in the above embodiment, protect the dimmer switch 12', and perform smooth switching.

Note that each of the above embodiments describes the dimmer switch 12, 12' in a high frequency discharge lamp lighting device using an inverter IN.
Although the present invention has been shown to prevent arc generation, it goes without saying that the present invention can also be applied to a commercial frequency discharge lamp lighting device.

[Effects of the Invention] According to the discharge lamp lighting device of the present invention, it is possible to prevent the occurrence of contact arc of the dimmer switch when switching from the full lighting state to the dimmer lighting state, thereby preventing damage to the dimmer switch. , and can perform smooth switching.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a first embodiment of this invention, FIG. 2 is a timing diagram of each part thereof, FIG. 3 is a circuit diagram of a second embodiment of this invention, and FIG. 4 is a circuit diagram of a second embodiment of this invention. The circuit diagram of the third embodiment, FIGS. 5 and 6 are the circuit diagrams of the conventional example, and FIG.
The figure is a schematic diagram of a switch structure in an embodiment. 12...Dimmer switch, 13...Discharge lamp, 15...
・Saturable reactor, 16... switch, 17...
DC power supply 1N in + Y-'5'3t! Figure 2 Figure 3 Figure 4 Figure 6 Figure 7 Prisoner-F) 19-

Claims (1)

[Claims] A dimmer switch with a contact that is inserted in the power supply path to the discharge lamp and fully lights up the discharge lamp when it is closed and dims the discharge lamp when it is opened; and a dimmer switch that is connected in parallel to the dimmer switch. It includes a saturable reactor, a DC power source that supplies an exciting current to the saturable reactor, and a switch inserted between the saturable reactor and the DC power source, and the switch is turned on immediately before or at the same time as the dimmer switch is opened. A discharge lamp lighting device, wherein the switch is opened after the dimmer switch is closed and the switch is opened.