JPS5954197A - Device for dimming 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] The present invention relates to a discharge lamp dimming device. .

A situation where the lamp voltage of a discharge lamp is approximately equal to the power supply voltage.

In this case, a step-up transformer is not used as shown in FIG.

As shown, the polarity of choke coil 2 and lamp current is reversed.

The switching circuit 4 is turned on when the current value reaches a predetermined current value, and turned off when the current value reaches a predetermined value.

A lighting device that lights a discharge lamp 3 every cycle using an AC power source 1 is a one-cage lighting device that has been commonly used in the past.

Lighter weight and lower loss compared to lighting devices that use transformers.

Loss can be measured. FIG. 2 shows the operation during lighting of the discharge lamp 3 in the 5-lamp-per-cycle device described in 2.

This is explained by In the figure, vl is the voltage of power supply 1.

Waveform, Vl is lamp voltage waveform, ■ is restriking pulse voltage, it is lamp current, 1. is to switching circuit 4.

This is the switching current that flows. At time t1 when the lamp current of the previous half cycle 10 finishes flowing, the switching circuit/circuit 4
turns on, and a gradually increasing switching current i flows through the switching circuit 4, accumulating electromagnetic energy in the choke coil 2. At time 1'it2 when the value of the switching gummy current is reaches a predetermined current value Icut I, the switching circuit 4 is turned off. Therefore, a high voltage pulse voltage is applied to both ends of the choke coil 2.

V is generated and the discharge lamp 3 is re-ignited. Then the discharge lamp.

3, the energy stored in the choke coil 2 is connected to the power source 1.
It is applied superimposed on the energy from the above...
With t1 as the initial value, a smooth lamp current 1t flows until time t3 when the half-cycle lamp current ends, and at time t3 the polarity is reversed, and thereafter it is the same as from t1 to t3.

Repeat the operation and keep the light on steadily. Every Zaik above.

In order to perform dimming in a lighting device, the switching current ], the cut-off current value Icut ] must be decreased and the switching current
Means for reducing the initial value of the lamp current 11 at '.

However, when using this method, the dimming level must be set to a deep level.

There is a disadvantage that when the discharge lamp 3 becomes unstable, it becomes difficult to obtain the necessary dimming characteristics. 10 The present invention can be used even if the dimming level is deepened except for the drawbacks mentioned above.

In order to obtain a dimmer that lights up stably enough.

The switching circuit is turned on in the current interrupting switch/lamp circuit of the discharge lamp lighting device every cycle.

It is characterized by installing means to delay the phase from the phase when all lights are on.

Next, embodiments of the present invention will be described with reference to the drawings. .

FIG. 3 explains the principle of the discharge lamp dimming device according to the present invention.

FIG. 4 is a waveform diagram showing operation in a dimming state.

FIG. 5 is a circuit diagram showing an embodiment of the present invention, and FIG. 6 is the upper part.

A specific example of the configuration of the switching circuit according to the embodiment described above.

The circuit diagram shown in FIG. 7 shows the switching of the above embodiment.

FIG. 8 is a circuit diagram showing still another embodiment of the present invention, without showing another embodiment that can replace the elements.

It is a circuit diagram. In the principle explanatory diagram of FIG. 3, a switching transistor 6 and the switching transistor are shown.

base control circuit 7 that supplies base current to the transistor 6;
is connected in parallel with the discharge lamp 3 via the full-wave rectifier 5,
It constitutes a switching circuit 4. .

The operation of this circuit when all lights are on is as shown in Figure 2.
This is the same as the previous example, and its operation is as shown in the waveform diagram of FIG. The present invention is characterized by configuring the base control/control circuit 7 so that during dimming, the switching register 6 is turned on with a delay of a necessary phase compared to when all lights are on. l). The operation in this case will be explained using the waveform diagram in Figure 4.

To be clear, during the lighting period of the previous half cycle.

Although the switching circuit 4 remains off, it is released.

Switching occurs due to a phase delay from time t5 when the power ends.

Switch 1 until time t6 when lamp circuit 4 is turned on.
1. 3. The lamp circuit 4 continues to be off. At time t6.

When the switching circuit 4 is turned on, a switching current iS flows through the choke coil 2°, and a predetermined breaking current value “Icu” flows through the choke coil 2°.
At time t7 when t2 has arrived, the switching circuit 4 is turned off.

To do so. At this point, a high pulse voltage V, is applied 5 and the discharge lamp 3 is re-ignited, after which the lamp becomes smooth.

Current IL flows until time t8 at the end of the half cycle. .

From time t5 to t6, the lamp voltage is the power supply voltage.

Since they are approximately the same, the discharge lamp 3 cannot be re-ignited unless a re-ignition pulse voltage is applied, and therefore no lamp current flows. The above operation is repeated and the discharge lamp 3
lights up, but since the lamp output has a rest period between time t5 and t6, the cutoff current value Icut2 is made equal to the cutoff current value Icutl when all lights are on. The light state is maintained 1"b" 1 Cutoff current value Icut 2 is the cutoff current value when all lights are on, Ic
If it is smaller than ut l, the dimming level becomes even thicker.
I can do that.

In addition, since the instantaneous value of the lamp voltage Vz tends to be almost constant regardless of the value of the lamp current '11,
- In order to keep the lamp power constant, the lighting period of the discharge lamp 3 must be short (the lamp current '11 must be increased as much as possible).

Therefore, the degree of cooling of the electrode is small.

The light control device using the phase control of the invention can perform a more stable light control operation than the light control device that changes only the cut-off current value.

In one embodiment of the present invention shown in FIG.

consymmetrical switch) 8 and dimming switch.

phase control means consisting of a parallel circuit of a switch 10 and a resistor 9;

The switching circuit 401 connected to
Although the switching circuit 401 to which the phase control means A is connected is connected to the intermediate tap provided between the windings 201 and 202 of the oil coil 2, the switching circuit 401 connected to both ends of the discharge lamp 301 cannot be good. ” - Specifics of the switching circuit 401
An example of such a configuration is shown in FIG. In this configuration example, resistors 18 and 15
A resistor 17 and a voltage sensitive switch (for example, 5BS) 16 are connected in series, one end of a resistor 18 is connected to the anode of an SCR (silicon control rectifier) 12, and a resistor 18 and a resistor 1 are connected in series.
Connect the connection point of 7 to the gate of 5CR12 in 1.
2 are connected to the collector of the transistor 13, and the connection point between the Jl resistor 17 and the voltage sensitive switch 16 is connected to the base of the transistor 16, and the -' end of the voltage sensitive switch 16 is connected to the collector of the transistor 13. die between the emitter and the emitter.

Connect the resistor 15 through the ode 14 and connect these to the full wave.

The AC side 5 of the full wave rectifier 501 is connected to the rectifier 501.
A switching circuit 401 is constructed by inserting a capacitor 19 in parallel to the terminal. ”Second episode of Suirang.

When the voltage sensitive switch 16 on the line 401 is in the off state, the transistor 13 and the SCR 12 are connected to the switching circuit 4.01 through the full-wave rectifier 501, the resistor 18, and the resistor 17.
The switching circuit 401 is turned on by detecting the 10 voltage across the terminal, and the switching circuit 401 is turned on. and switching circuit.

Resistance due to the current flowing through 401] due to the voltage drop of 5 °
, the voltage sensitive switch 16 has a break-off voltage across it.

It turns on when the -bar voltage is reached. Therefore, (1) the base current of the transistor 13 becomes 0 and turns off.
Subsequently, SCR12 is also turned off and switching circuit/circuit 4
01 is in the off state. Then the voltage sensitive switch 16
While the voltage across the switching circuit 401 is above a predetermined voltage, a current greater than the holding current flows through the resistor 18, 17 to maintain the on state, and the switching circuit 401 remains on.

Line 401 remains off. switching circuit 40].

When the voltage across the voltage drops below a predetermined voltage, the voltage sensitive switch 16 turns off and switches the switching circuit.

path 401 is reset. ” - discharge lamp 3o with the operation described below.
15 can be fully lit. Note that the diode 14 in the wiring circuit is in the ON state of the voltage sensitive switch 16.

The emitter potential of transistor 13 is lower than the base potential.

The switching circuit 401 has an avalanche diode 101 for protection.
1 is connected.

Next, the operation during dimming of this embodiment will be explained with reference to the waveform diagram of FIG. 4. sss s in FIG. 5 is the power supply voltage.

Set the breakover voltage VBO lower than the peak value.

do. When the dimming changeover switch 10 is opened to set the dimming state, even if the previous half-cycle discharge ends at time t5 and the switch lamp circuit 401 is turned on, 5s88 is because the power supply voltage is lower than VHO. Does not turn on. Power supply 1 at time t6
When the voltage of 5SS8 reaches the VBO of 5SS8, SSS8 and the switching circuit 401 are turned on.
7. Become. At time t7, the switching circuit 401 is turned off.

When it is turned off, the current flowing through SSS 8 becomes less than the holding current, and SSS 8 turns off. Sui between time t7 and t8.

To ensure that the locking circuit 401 is kept in the OFF state.

causes a current higher than the holding current of the five voltage sensitive switches 16 of the switching circuit 401 to flow through the resistor 9.

Do it like this. Note that the lamp voltage Vz from time t7 to time t78.

If the instantaneous value is below VI30 of 5S88, the resistor 9 may be omitted.

FIG. 7 shows the switching element 10ss of the above embodiment.
ss is a circuit diagram showing another embodiment that can be replaced with ss. ” - Since the SSS 8 can only be turned on at a phase before the peak value of the voltage of the power supply 1, it is not possible to increase the dimming and brightness sufficiently. The circuit shown in FIG. 7 uses a double integration circuit consisting of a resistor 23, 25 and a capacitor 22, 24 and a trigger element 21 to conduct the bidirectional 3 terminal thyristor 20. It is possible to set the phase to a value after the peak value of , and the degree of dimming can be made close to 100%. Furthermore, in this circuit, continuous dimming can be performed by changing the resistor 25 or 23 by 2°.8. .

In this embodiment, the phase control means A including the circuit shown in FIG. 7 is added to the switching circuit 401 as shown in FIG.

The circuit is turned on later than the phase when all lights are turned on, and a stable dimming state can be obtained.

FIG. 8 is a circuit diagram showing still another embodiment of the light control device according to the present invention. Sui in this example.

The Lang circuit 401 is basically the same as that shown in FIG.

The circuit configuration is the same as that of the embodiment. The phase 10 control means A of this embodiment has a resistor 26, a resistor 28, and a resistor 29 connected in series.
A resistor 34 and a capacitor 27 are connected in parallel to the resistor 28.
A diode 30 is connected in parallel to the resistor 29, and a voltage sensitive switch 31 and a dimming switch 32 are connected in parallel to both ends of the resistor 28 and the resistor 29, respectively.
Connect the connection point between the resistor 28 and the resistor 29 to the base of one transistor, and connect the collector of the transistor to the connection point between the resistor 17 and the voltage sensitive switch 16 of the switching circuit 401. The other end of the voltage sensitive switch 16 is connected to the emitter of the transistor 19 and the connection point between the resistor 29 and the anode of the diode, and the open end of the resistor 26 is connected to the switching circuit 401.
of.

Connected to the anode of 5CR12. Dimming selector switch 3
When all lights are turned on with the switch 2 turned on, the same operation as when all lights are turned on in the above embodiment is performed. The operation when dimming the light with the dimming changeover switch 32 in the OFF state will be explained with reference to the waveform diagram shown in FIG. 4'. of the previous half cycle.

At time t5, when the discharge has almost finished, the voltage applied to the switching circuit 401° becomes 0 due to the polarity reversal, so there is a feeling of heavy pressure.

The corresponding switches 16 and 31 are both turned off, and the voltage of the switching circuit 401 rises immediately thereafter.

Transistor 19 is connected to resistor 26 and capacitor 27.

and turn on. This time is transistor 13°,
Set it so that it is before SCR12 turns on.
It is. If one of the above transistors is on, 5S
CR12 and transistor 13 remain off, and
The full-wave rectifier 5 and the switching circuit 4 are substantially in an OFF state. When the transistor 19 is on, the current flowing through the voltage sensitive switch 16 is less than or equal to the holding current, so the voltage sensitive switch 16 returns to the off state. Since the lamp current is O from time t5 to t6,
A voltage is connected to both ends of the switching circuit 401.

The voltage of source 1 appears. Therefore, resistance 26, Conde.

Transistor 19 remains on through sensor 27, and capacitor 27 is charged. Capacitor 5 at time t6
The voltage at 27 is the breakover of the voltage sensitive switch 31.

The voltage is reached and the voltage sensitive switch 31 is turned on.

Then, the transistor 19 turns off and becomes voltage sensitive.

Since the switch 16 is in the OFF state, SCR]2 and G.

The transistor 13 is turned on. Capacitor 33 is 1
0 Insert to ensure turn-on at this time. Voltage sensitive switch 1 due to voltage drop across resistor 15
6 reaches the breakover voltage at time t7
Then, the voltage sensitive switch 16 turns on, and the transistor 13 and 5CR1, 2 turn off and the switch 16 turns on.
The switching circuit 401 is turned off. Therefore·
A high voltage pulse voltage V is generated and the discharge lamp 301 is lit.
.

After that, a holding current is passed through the resistor 18.17 to create a feeling of heavy pressure.
The response switch 16 remains on, and the transistor 19.
The discharge lamp 301 is turned on so that it remains off.
11. Continue. This is to keep the transistor 19 off.

At time t6, the voltage sensitive switch 31 is turned on.

After that, the discharge current of the capacitor 27 until time t7.

It is necessary to keep the voltage sensitive switch 31 in the on state.

The resistor 34 increases the discharge time constant of the capacitor 27 by 5
6 to t7 due to the discharge of the capacitor 27.

It is connected to keep the voltage sensitive switch 31 in the on state. Between times L7 and L78, the voltage across the switching circuit 401 causes the voltage sensitive switch 31 to change.

A holding current flows to maintain the on state. The resistor 28 is a resistor for discharging the capacitor 27, the diode 30 is a shunt resistor when the capacitor 27 is discharged, and the resistor 29 is a shunt resistor between the base and emitter of the trunk star 19.

Ru.

As mentioned above, in this embodiment, the phase control means A is controlled by the striking force lll5.
By doing so, the phase at which the transistors 13 and 5CR1, 2 of the switching circuit 401 are turned on can be delayed from the phase when all lights are turned on, so that a stable dimming state can be obtained.

The present invention is a 2Q lighting circuit for every cycle of a discharge lamp.

, 12・ Phase to the switching circuit for current interruption as above.

The above current interruption can be achieved by adding a control means.

The switching circuit turns on the phase of the full light point.

The phase should be delayed by the necessary amount from the phase when the light is on.

Therefore, it is possible to obtain the dimming device 5 in a stable dimming state with a deep dimming degree. Also, in the examples of the present invention.

7, and the resistor 25 of the circuit shown in FIG.

If the resistor 26 in the circuit shown is changed to a variable resistor, a light control device that performs continuous light control can be obtained.

[Brief explanation of drawings]

Figure 1 is a circuit diagram showing the every-cycle lighting device, Figures 2 and 2 are the operating waves and shapes of the above-mentioned every-cycle lighting device during lighting, and
Figure 4 is an explanatory diagram of the principle and theory of the discharge lamp dimmer according to the present invention.
5 is a circuit diagram showing an embodiment of the present invention, and FIG. 6 is a specific configuration example of the switching circuit of the above embodiment. 7 is a circuit diagram showing another embodiment that can replace the switching element of the above embodiment,
FIG. 8 is a circuit diagram showing still another embodiment of the present invention. 201... AC power supply 2... Choke coil 301... Discharge lamp 401... Switching circuit. A: Junnosuke Nakamura, patent attorney representing phase control means. 0 5 0 ・15 ・ 1-1 Figure 2

Claims (1)

[Claims] An AC power supply, a choke coil, and a discharge lamp having a lamp voltage approximately equal to the voltage of the AC power supply. The two discharge lamps are connected in substantially parallel with each other in a series closed circuit. The lamp current of the above discharge lamp is continued every half cycle. When the polarity is reversed, the lamp current turns on. It turns off when the current reaches a predetermined value.1'1
A discharge lamp dimmer comprising a switching circuit as described above, and further comprising a phase control means added to the switching circuit for delaying the phase at which the switch-on lamp circuit is turned on by a necessary phase compared to the full-light lighting state.・