JPS6326519B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a discharge lamp lighting device.

As shown in FIG. 1, the conventional first discharge lamp lighting device includes a chiyoke coil 2 serving as a discharge lamp ballast and a regulator between one end of an AC power supply 1 and one end of one filament f ₁ of a discharge lamp 4. Connect the series circuit of the light coil 3, connect the other end of the AC power supply 1 and one end of the other filament f ₂ of the discharge lamp 4, and connect the other ends of the filaments f ₁ and f ₂ of the discharge lamp 4. A starter 5 such as a glow starter is connected, a series circuit of a timer circuit 7 and a switch 6 is connected between both ends of the AC power source 1, and a normally closed contact 8 of the timer circuit 7 is connected in parallel with the choke coil 3.
In this case, by turning on the switch 6, the timer circuit 7 performs a timer operation if the AC power supply 1 is turned on, and opens the normally closed contact 8 after a certain period of time has elapsed.

Next, the operation will be explained. When the AC power supply 1 is turned on with the switch 6 turned off (all-light state), the timer circuit 7 does not operate, the normally closed contact 8 remains closed, and the starter 5 performs normal preheating (all-light preheating). ), the starter 5 is turned off and the discharge lamps 4 are fully lit.

In addition, when the switch 6 is turned on in the fully lit state, the timer circuit 7 operates, and after a certain period of time, the normally closed contact 8 shifts from the closed state to the open state, and the discharge lamp 4 changes from the fully lit state to the dimming state. Transition to lighting state.

Also, when the AC power supply 1 is turned on with the switch 6 turned on (dimmer state), the timer circuit 7 operates, but since the normally closed contact 8 is initially closed, the starter 5 performs normal preheating. (Full light preheating)
After this, the starter 5 is turned off and the discharge lamp 4 is fully lit, and when the timer circuit 7 times up, the lighting is switched to dimming mode.

Since the discharge lamp lighting device having such a configuration always preheats the discharge lamp 4 with full light, there is no problem of insufficient current for preheating at the time of dimming start, and no difficulty in starting occurs. However, since the timer circuit 7 is required,
There is a problem that the circuit configuration becomes complicated and expensive, and when switching from full lighting to dimmed lighting, there is a certain time delay in the switching operation, which may cause a sense of discomfort. Furthermore, since preheating is stopped when the discharge lamp 4 is turned on, the filament temperature during dim lighting is lower than when it is fully lit, resulting in a problem that the life of the discharge lamp 4 is shortened.

As shown in FIG. 2, the conventional second discharge lamp lighting device includes the switch 6 and the timer circuit 7 shown in FIG.
is removed, a switch 9 is connected in parallel to the choke coil 3, and the filament of the discharge lamp 4 is connected in parallel to the switch 9.
A capacitor 10 is inserted between the other ends of f ₁ and f ₂ in series with the starter 5, and a switch 9' which operates in conjunction with the switch 9 is connected in parallel with the capacitor 10.
In this case, the values of the choke coil 3 and the capacitor 10 are set to a series resonance constant at the frequency of the AC power supply 1 (commercial frequency).

Next, the operation will be explained. switch 9,
AC power supply 1 with 9' turned on (full light state)
When the starter 5
After proper preheating is performed, the starter 5 is turned off and the discharge lamp 4 is fully lit.

When the switches 9 and 9' are turned off in the full lighting state, the influence of the chiyoke coil appears and the lighting immediately shifts to the dimmed lighting state.

State with switches 9 and 9' turned off (dimmer state)
When AC power supply 1 is turned on, AC power supply 1 → Chiyoke coil 2 → Chiyoke coil 3 → Filament f ₁
→ Capacitor 10 → Starter 5 → Filament f ₂
→A filament preheating current flows in the path of the AC power supply 1, but since the chiyoke coil 3 and the capacitor 10 are in a series resonance state, their influence is equivalently removed and the preheating current at the same level as the starting preheating current under full light conditions is reached. The preheating current at startup also flows during dimming, so there is no problem of difficulty in starting when dimming. Furthermore, if the reactance of the capacitor 10 is made larger than the reactance of the chiyoke coil 3, it is possible to flow a preheating current larger than that in full light.

However, in such a configuration, the capacitor 10 becomes very large at commercial frequencies. Further, when the starter 5 is on (during operation), the voltage of the capacitor 10 generated by the preheating current is applied between the filaments f ₁ and f ₂ of the discharge lamp 4, and this voltage is in a series resonance state. The voltage is quite high.

Now, the inductance L ₁ as shown in Fig. 3,
L ₂ , resistors R ₁ and R ₂ , and capacitor C. When the input voltage and output voltage are V _i and V ₀ , the impedance Z _i seen from the input side is Z _i =jω(L ₁ +L ₂ )−j1/ωC where ω is the angular frequency.

becomes. Now, since ωL ₂ =1/ωC, Z _i =jωL ₁ , and therefore, the current i becomes i=V _i /Z _i =V _i /jωL ₁ . The output voltage V ₀ becomes V ₀ =i×1/jωC=V _i /−ω ² L ₁ C. However, in the above formula, the resistances R ₁ and R ₂
is omitted. Now, V _i =100V, ω=2πf=377
(f is frequency), L ₁ = L ₂ , R ₁ = R ₂ = 0, then
V ₀ =100V.

Therefore, if a voltage is applied between the filaments f ₁ and f ₂ of the discharge lamp 4 during preheating, and the secondary voltage is high such as in a step-up ballast or an inverter ballast, the preheating may remain insufficient. There was a possibility that the discharge lamp 4 would start up, and the life of the discharge lamp 4 would be shortened. Further, like the one in FIG. 1, there was also the problem that the filament temperature during dimming lighting decreased, shortening the life of the discharge lamp 4.

The conventional third discharge lamp lighting device, as shown in FIG. 4, removes the capacitor 10 and switch 9' shown in FIG. be.

The operation will be explained. When the AC power supply 1 is turned on with the switch 9 turned on (full light state),
As with the one in Fig. 2, all lights are on, and when the switch 9 is turned off in this state, it immediately shifts to the dimming lighting state, and the filaments f 1 and f 2 of the discharge lamp 4 are constantly connected to the filaments f ₁ and f ₂ of the discharge lamp 4 from the secondary winding of the yoke coil 3. A preheating current is supplied.

When the AC power supply 1 is turned on with the switch 9 off (dimmer state), the starter 5 operates, and a preheating current flows through the filaments f ₁ and f ₂ during starting, which is lower than when the light is on, and the starter 5 is turned off. After that, the discharge lamp 4 is dimmed and lit.

In a discharge lamp lighting device with such a configuration, since a preheating current is constantly flowing during dimming, a drop in filament temperature can be prevented, but since the preheating current is small at the time of starting during dimming, there is a problem of difficulty in starting. There was a risk that this would occur.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a discharge lamp lighting device that has excellent startability during dimming, can extend lamp life, and has a simple configuration.

An embodiment of this invention is shown in FIGS. 5 to 7. That is, as shown in FIG. 5, in this discharge lamp lighting device, a chiyoke coil 2 serving as a discharge lamp ballast is connected between one end of an AC power supply 1 and one end of a filament f ₁ of a discharge lamp 4, and the AC power supply is The primary windings of current transformers 11 and 12 for preheating and a chiyoke coil 3 for dimming are connected in series between the other end of filament f ₂ of discharge lamp 4 and one end of filament f ₁ of discharge lamp 4. One end and current transformer 1
A starter 5 such as a timer switch or a glow starter is connected between the primary winding of F.2 and the connection point of the York coil 3, and a switch 9 is connected between the other end of the AC power supply 1 and one end of the filament _F.2 . , the secondary windings of current transformers 11 and 12 are connected between both ends of filaments f ₁ and f ₂ , respectively. In this case, the impedances Z ₁₁ , Z 12 , Z 3 of the current transformers 11, ₁₂ and the chiyoke coil ₃ are Z ₃ ≫
It becomes Z ₁₁ + Z ₁₂ .

Next, the operation will be explained. When the AC power supply 1 is turned on with the switch 9 turned on (full light state), the starter 5 is activated and a current _i0 flows as shown in FIG. Since the equivalent inductance of the current transformers 11 and 12 is very small, this current i ₀ is close to the secondary short-circuit current of the chiyoke coil 2. Most of the current i ₀ flows into the primary windings of the current transformers 11 and 12 as a current i ₁ and contributes to preheating the filaments f ₁ and f ₂ . That is,
The preheating contribution current i ₁ that flows during full light is i ₁ = i ₀ − i ₂ when the current flowing through the chiyoke coil 3 is i ₂ , and i ₁ = i ₀ ×Z ₃ /Z ₃ +Z ₁₁ +Z ₁₂ Become. In this case, since the current i ₂ has a fairly small value, no high voltage is applied between the filaments f ₁ and f ₂ even when the starter 5 is on. Thereafter, the starter 5 is turned off, the discharge lamp 4 is fully lit by the AC power supply 1 via the chiyoke coil 2, and the preheating of the filaments f ₁ and f ₂ is stopped.

When the switch 9 is turned off in the fully lit state, the lamp current flows through the switch coil 3 and the current transformers 11 and 12, and the discharge lamp 4 is switched to the dimming lighting state by the switch coil 3, and the current transformers 11 and 12 are turned off. As a result, a preheating current is constantly supplied to the filaments f ₁ and f ₂ . Since the constant preheating current in this case is considerably smaller than the current i ₀ , the constant preheating current is naturally smaller than the starting preheating current during full light.

When the AC power supply 1 is turned on with the switch 9 turned off (dimmer state), a current i ₀ ' flows as shown in Fig. 7, and all of this current i ₀ flows through the current transformers 11 and 12 to preheat it. This will contribute to In this case, the impedance of the chiyoke coil 2 is the impedance of the preheating transformers 11 and 12.
Since it can be assumed that Z ₁₁ and Z 12 are sufficiently large compared to Z 11 and Z ₁₂ and can be considered as a constant current circuit, i ₀ ′≒i ₀ , so current i ₀ flows through the current transformers 11 and 12, and the preheating contributing current is the current i ₂ from full light starting
The amount of heat is increased by the same amount, and sufficient preheating is achieved even when starting dimming.
After that, the starter 5 is turned off and the discharge lamp 4
becomes dimmed and lights up, and the filament
Preheating current is constantly supplied to f ₁ and f ₂ .

As a result of this configuration, even when the discharge lamp 4 is started in a dimmed state, preheating at the time of startup can be sufficiently performed, and the startability in dimming can be improved. Also, during preheating, filaments f ₁ and f ₂
Since no high voltage is applied during this period, the lamp life will not be shortened. Furthermore, since the filaments f ₁ and f ₂ are constantly preheated during dimming lighting to prevent a decrease in filament temperature, the lamp life can be extended. Furthermore, since no preheating current is allowed to flow during full lighting, lighting efficiency can be increased. Further, a timer circuit or the like is not required and the configuration is simple.

Another embodiment of the invention is shown in FIG. That is, this discharge lamp lighting device uses an inverter type ballast 2' instead of the chiyoke coil 2 as a discharge lamp ballast, and other configurations and effects are the same as those of the previous embodiment.

As described above, the discharge lamp lighting device of the present invention has the following features:
A discharge lamp with one end of its filament connected to one power input terminal, a dimming coil with one end connected to one end of the other filament of the discharge lamp, and the other end of the dimming coil. and the other power input terminal, and have their own secondary windings connected between the ends of the one and the other filaments of the discharge lamp, respectively. A preheating current transformer, a starter connected in parallel to a series circuit of the discharge lamp and the dimming coil, and primary windings of the dimming coil and the first and second preheating current transformers. Since it is equipped with a dimmer switch connected in parallel to a series circuit, it has the advantage of excellent starting performance when dimming, prolonging the lamp life, and simple configuration.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a first conventional discharge lamp lighting device, FIG. 2 is a circuit diagram of a second conventional discharge lamp lighting device, FIG. 3 is a circuit diagram for explaining the problems, and FIG. 4 is a circuit diagram of a conventional third discharge lamp lighting device, FIG. 5 is a circuit diagram of a discharge lamp lighting device according to an embodiment of the present invention, and FIGS. 6 and 7 are circuits for explaining the operation thereof. 8 are circuit diagrams of a discharge lamp lighting device according to another embodiment of the present invention. 1...AC power supply, 2...Chiyoke coil, 3...
...Charge coil, 4...Discharge lamp, 5...Starter, 9...Switch, 11, 12...Current transformer.

Claims (1)

[Claims] 1. A discharge lamp with one end of its filament connected to one power input terminal, a dimming coil with one end connected to one end of the other filament of this discharge lamp, and the other parts of the dimming coil. first and second filaments each having their own primary winding connected between one end and the other power input end and having their own secondary winding connected respectively between the ends of one and the other filament of said discharge lamp; a starter connected in parallel to a series circuit of the discharge lamp and the dimming coil; and one of the dimming coil and the first and second preheating current transformers.
A discharge lamp lighting device equipped with a dimmer switch connected in parallel to a series circuit with the next winding.