JPS5829598B2 - discharge lamp lighting device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvement of the starting characteristics at low temperatures of a discharge lamp lighting device which is capable of dimming using a cyrisk device, and to improvement of lighting characteristics against fluctuations in power supply voltage.

In this type of lighting device, it is sometimes difficult to start in dimming conditions O, especially in low temperatures, and if the power supply voltage fluctuates while the dimming is on, the desired dimming cannot be achieved. Not only could the condition not be obtained, but if the voltage fluctuated in a decreasing direction, sufficient lamp current could not be obtained and the discharge lamp would go out, or if a starter was used, the starter would restart.
In order to solve these problems at the same time, there was a drawback that the degree of dimming, especially around room temperature, had to be set loosely in advance.

Therefore, from this point of view, it has been desired to improve the starting characteristics at low temperatures and the lighting characteristics against power supply voltage fluctuations.

The present invention was made in consideration of these circumstances, and at low temperatures, the conduction phase of the Cyrisk device is automatically delayed, the degree of dimming is relaxed from the set value, and the conduction phase of the Cyrisk device is adjusted in response to fluctuations in power supply voltage. By changing the phase, it can be started reliably even at low temperatures, the degree of dimming does not change even when the power supply voltage fluctuates, and good lighting characteristics are obtained without fading or fading. An object of the present invention is to provide a discharge lamp lighting device that can be set deeply.

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

Reference numeral 1 denotes an AC power source, and a discharge lamp, such as a fluorescent lamp, is energized from this power source 1.

A parallel circuit of a lighting tube 3 and a noise prevention capacitor 4 is connected between the non-power supply side electrodes of the discharge lamp 2.

A cyrisk device 5 and a ballast 6 are connected in series between the power source 1 and the discharge lamp 2.

The thyrisk device 5 is, for example, a triac, an SCR connected in antiparallel, or the like.

Further, a control circuit 7 is connected to the cyrisk device 5.

This control circuit 7 will be explained in detail.

First, a double-wave rectifier circuit 10 is connected between both ends of the power source 1 by connecting one input terminal to the resistor 8 and the control pole of the thyrisk device 5, and connecting the other input terminal to the resistor 9. A 5CR11 constituting a switching device 25, which will be described later, is connected between the output terminals of the rectifying circuit 10 in the forward direction, and a voltage dividing circuit 12 and a voltage regulating circuit 13 are connected in parallel with the 5CR11.

The voltage dividing circuit 1') includes a series circuit of a temperature-sensitive resistor 14 and a resistor 15 whose resistance changes in response to the surroundings during startup, and a resistor 16.
These connection points are defined as voltage division points a.

The temperature-sensitive resistor 14 is, for example, a thermistor with a negative characteristic, and increases its resistance when the ambient temperature is low to lower the potential at the voltage dividing point a.

Further, the voltage lowering circuit 13 includes a resistor 17 and a constant voltage diode 18.

A resistor 19 and a capacitor 20 are connected between the output terminals of the voltage regulator circuit 13, that is, across the voltage regulator diode 18.
A fixed time circuit 21 consisting of the following is connected.

Further, an anode A1 gate G is connected between the output terminal of the time constant circuit 21 and the voltage dividing point a of the voltage dividing circuit 12, and a PUT 22 is connected thereto.

The cathode of this PUT 22 is connected to the negative terminal of the rectifier circuit 10 via a resistor 23 and to the gate electrode of the thyristor 11 via a resistor 24.

These PUTs 22 and the 5CR 11 mainly constitute the switching device 25.

As is well known, when the potential of the anode A reaches a predetermined value with respect to the potential of the gate G, the PUT 22 determines that the potential at the output terminal of the time constant circuit 21 in this embodiment is divided. It becomes conductive when the potential at pressure point a reaches a predetermined value.

Therefore, at this time, 5CRI1 is given a signal to its gate and becomes conductive.

Then, due to the conduction of this 5CR11, the double wave rectifier circuit 1
A short-circuit current flows through the closed circuit of 0 and 5CR11, which generates a gate signal and turns on the cyrisk device 5.
It is something that makes you

Therefore, it can be easily understood that the generation phase of the gate signal is determined by the potential of the voltage dividing point a and the output terminal of the time constant circuit 21.

However, while the potential at the voltage dividing point a changes due to resistance changes due to changes in the ambient temperature of the temperature sensitive resistor 14 or fluctuations in the power supply voltage, the potential at the voltage dividing point
3, it is almost unaffected by changes in ambient temperature and fluctuations in power supply voltage.

Therefore, if the potential at voltage dividing point a becomes relatively high, PU
When the conduction of T22 is delayed, the generation phase of the gate signal is delayed, and conversely, when the potential at the voltage dividing point a becomes relatively low, PUT2
2 becomes conductive earlier, and the generation phase of the gate signal becomes earlier.

This is illustrated in Figure 2.

FIG. 2 is an enlarged and simplified diagram showing the transition of the conduction phase of the PUT 22 due to changes in the voltage dividing point a, that is, the gate potential.

Note that PUT becomes conductive when the anode potential (I) becomes slightly higher than the gate potential (G);
A and.

■It is shown that conduction occurs when G becomes equal.

From this, when the ambient temperature is low, the resistance of the temperature-sensitive resistor 14 increases, lowering the potential at the voltage dividing point a to quickly turn on the PUT 22, and when the power supply voltage fluctuates, the potential at the voltage dividing point a changes. It can be understood that the conduction phase of PUT 22 is changed by

In this embodiment, the constants of the control circuit 7 are selected, and the desired degree of dimming is set, for example, when the ambient temperature is 30° C., for example, to a 60% luminous flux ratio (the luminous flux ratio when the entire lamp is lit at the same temperature). ratio.

), and when the temperature is lower than the reference temperature, the degree of dimming is relaxed to start and light up, so that the conduction phase of the PUT 22, in other words, the generation phase of the gate signal is determined.

However, as is well known, the degree of dimming can be changed by making the constants of the control circuit 7, such as the time constant circuit 21, variable.

The resistor 26 in the control circuit 7 is used for so-called cosine modulation to linearly rise the potential at the output terminal of the time constant circuit 21.

Also, a resistor 27 connected in parallel with the cyrisk device 5
The series circuit of the capacitor 28 and the capacitor 28 is for protecting the cyrisk device 6 from the surge voltage generated when the lighting tube 3 is operated.

Next, the effect will be explained.

In a dimming lighting state where the dimming level is set to 60%,
When the ambient temperature is 30° C. at the time of starting the discharge lamp 2, the phase-controlled and attenuated power is supplied from the AC power supply 1 by the cyrisk device 5, and the discharge lamp 2 is supplied with the desired 60% luminous flux set above. It starts and lights up at the ratio.

At this time, even if there is a fluctuation in the power supply voltage, the generation phase of the gate signal will change according to the increase or decrease in voltage, and the phase at which the Cyrisk device 5 turns on will be delayed or accelerated, so that the discharge lamp or the 60% luminous flux ratio can be adjusted. It starts and lights up while maintaining the brightness.

Therefore, there is no voltage fluctuation (thereby causing the degree of dimming to change or the discharge lamp 2 to go out).

However, if the ambient temperature at the time of startup is 30° C., that is, lower than the reference temperature, the resistance of the temperature-sensitive resistor 14 increases and the potential at the voltage dividing point a becomes low.
As shown in the figure, the PUT 22 becomes conductive at an early phase, and the generation phase of the gate signal is advanced.

Therefore, the cyrisk device 5 has the reference temperature of 30°.
Since it is turned on at an earlier phase than in case C, the discharge lamp 2 is supplied with electric power with relaxed phase control, and starts and lights up.

That is, at this time, the discharge lamp 2 is started and lit at a luminous flux ratio in which the degree of dimming is relaxed from the 60% luminous flux ratio.

Since the resistance of the temperature-sensitive resistor 14 changes in response to the ambient temperature, and the potential at the voltage dividing point a changes accordingly, the generation phase of the gate signal advances as the ambient temperature decreases, and as the ambient temperature decreases, the gate signal generation phase advances. The degree of dimming is gradually relaxed.

Therefore, even when the ambient temperature is low, the discharge lamp does not become difficult to start and can be started reliably.

In this case, even if the power supply voltage fluctuates, the cyrisk device 5 is turned on according to the increase or decrease in voltage as described above.
Since the phase of the lamp 2 is delayed or advanced, there is no problem in starting and lighting the lamp 2.

Note that the temperature-sensitive resistor can be arranged so as to be substantially sensitive to the temperature of the ballast or the tube wall of the discharge lamp.

By arranging it in this way, it is possible to respond to the ambient temperature at the time of startup, and when the temperature is low, the potential of the voltage dividing point is lowered to turn on the thyrisk device at an early phase, and it is possible to turn on the cyrisk device at an early phase, and also to prevent the cyrisk device from turning on after the discharge lamp is turned on. The heat generated by the ballast, i.e., the temperature of the ballast or tube wall, rises and the resistance changes, increasing the potential at the voltage dividing point and delaying the ON phase of the Cyrisk device to achieve the desired degree of dimming. can.

Further, as the temperature-sensitive resistor, a thermistor with a positive characteristic or the like can be used in addition to a thermistor with a negative characteristic.

In short, it is sufficient if it is in the voltage dividing circuit and lowers the potential at the voltage dividing point when the ambient temperature is low.

Furthermore, by connecting not only one discharge lamp but many discharge lamps in parallel, it is possible to dim and light many lamps all at once by sharing one cyrisk device.

Furthermore, the reference ambient temperature and the degree of dimming at this time can be set arbitrarily.

It should be noted that a conventional dimming device has been proposed in which a temperature-sensitive resistor such as a thermistor is installed in the gate circuit of the Cyrisk device, but this does not require the user to The purpose is to slowly change the lighting level to provide a gentle atmosphere, and is unrelated to the purpose of the present invention, which is to improve starting characteristics at low temperatures.

In addition, a constant voltage circuit using a constant voltage diode and a PUT
A pulse oscillation circuit that combines this has also been proposed, but this conventional one attempts to oscillate a pulse with a constant phase even when the power supply voltage fluctuates by fixing the oscillation phase. Therefore, it is unrelated to the present invention in which the generation phase of the gate signal is changed in response to fluctuations in the power supply voltage.

As described in detail above, the present invention provides a control circuit for controlling the conduction of the Cyrisk device in which the light is adjusted using the Cyrisk device, and a control circuit that controls the conduction of the Cyrisk device when the ambient temperature is low when starting the discharge lamp. Since the phase is automatically advanced and the conduction phase of the cyrisk device is changed when the power supply voltage fluctuates, the discharge lamp can be reliably started and lit even at low temperatures, and the degree of dimming can be maintained even when the power supply voltage fluctuates. It is possible to provide a discharge lamp lighting device that does not cause a change in the temperature or cause the discharge lamp to go out.

Further, by being able to perform temperature compensation and power supply voltage compensation in this way, it is possible to set a deep limit on the degree of dimming in advance.

Moreover, it also has the effect of being relatively easy to configure.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram showing one embodiment of the present invention, and Fig. 2 is a circuit diagram showing an embodiment of the present invention.
FIG. 2 is a waveform diagram showing simplified and enlarged voltages in the main parts of the diagram. 1...AC power supply, 2...Discharge lamp, 5.
...Syrisk device, 6...Stabilizer, 7
...Control circuit, 10...Double wave rectifier,
12... Voltage dividing circuit, 13... Constant voltage circuit, 14... Temperature sensitive resistor, 21... Time constant circuit, 22... ...PUT, 25...
switching device.

Claims (1)

[Claims] 1. An AC power source; A discharge lamp energized from this power source; A cyrisk device and a ballast provided between the power source and the discharge lamp; When the ambient temperature is low, the thyristor device advances the conduction phase of the thyristor device, and in response to voltage fluctuations of the power supply, when the voltage increases, it delays the conduction phase of the thyristor device, and when the voltage decreases, the thyristor device A discharge lamp lighting device characterized by comprising: a control circuit for advancing the conduction phase of the power source; and a double-wave rectifier circuit for rectifying the AC voltage of the power source; a voltage dividing circuit including a constant voltage circuit and a temperature-sensitive resistor whose resistance changes in response to the ambient temperature at the time of starting; and a time constant circuit connected between the output terminals of the voltage constant circuit; a switching device that generates a gate signal that conducts when the potential at the output end of the time constant circuit reaches a predetermined value with respect to the potential at the voltage dividing point of the voltage dividing circuit to turn on the Sairisk device; 3. The discharge lamp device according to claim 1, wherein the temperature-sensitive resistor lowers the potential at the voltage dividing point to reduce the potential at the voltage dividing point due to a resistance change when the ambient temperature is low. In addition to advancing the signal generation phase, after lighting, the temperature rises due to the heat generated due to lighting, and the resulting resistance change increases the potential at the voltage dividing point, thereby delaying the generation phase of the gate signal. 4. The discharge lamp lighting device according to claim 2, wherein the temperature-sensitive resistor is a thermistor with positive or negative characteristics. 5. The discharge lamp lighting device according to paragraph 5. The switching device includes a PUT whose anode is connected to the output end of the time constant circuit and a gate is connected to a voltage dividing point of the voltage dividing circuit; an SCR whose poles are connected in the forward direction between the output terminals of the double-wave rectifier circuit; the SCR conducts with the conduction of the PUT to form a closed circuit with the double-wave rectifier circuit; 3. The discharge lamp lighting device according to claim 2, wherein the gate signal is generated by a flowing short-circuit current.