JPH0343992A - Discharge lamp lighting device - Google Patents

Abstract

PURPOSE:To stably light a discharge lamp while preventing going out by providing a control device connected so as to perform the control having a large term and a small term of output impedance of a power supply device at least in the output voltage impression term of a starting device. CONSTITUTION:A switching circuit 31 connected in parallel to the inductance 24 is controlled by a variable control device 30 to put the switching circuit 31 is a conductive state by one part of a half-period in terms of time. Accordingly, output impedance of a power supply device 11 is made bigger than the full-conductive state of the switching circuit 31 by enlarging the relative impedance of the inductance 24. When the switching circuit 31 is opened to make a lamp current to flow through the inductance 24, 25, a discharge lamp 13 shall be lighted by a rated lamp current. Thereby, the lamp current is temporally suppressed in the output voltage impression term of the starting device to prevent an output drop of the power supply device while stably starting the discharge lamp for improving building-up a flux of light.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a discharge lamp lighting device for starting and lighting a discharge lamp.

2. Description of the Related Art Conventionally, as a discharge lamp lighting device of this type, one shown in FIG. 5 is known. In Fig. 5, 1 is a power supply device;
2 is a starting device; 3 is a discharge lamp; the power supply device 1 is connected to the discharge lamp 3 via the starting device 2; In the conventional example, the power supply device 1 is composed of a DC power source and a high-frequency inverter including a current limiting element.The power supply device 1 also includes a magnetic circuit.Power is supplied to this type of discharge lamp lighting device. At this time, the output voltage of the power supply device 1, which is supposed to keep the discharge lamp 3 lit, rises, and at the same time, power is also supplied to the starting device 2.At this time, the starting device 2 turns on the discharge lamp 3 in order to start the discharge lamp 3. A high voltage pulse voltage necessary for breakdown between the main electrodes of the lamp is generated and applied to the discharge lamp 3.

After breakdown, current flows from the power supply device 1 to the discharge lamp 3 via the secondary winding 4 of the pulse transformer that constitutes the starter device 2. By the above operation, the discharge lamp 3 is lit for the first time.

Problems to be Solved by the Invention Generally, in this type of discharge lamp lighting device, the output current from the power supply device to the discharge lamp is increased at the time of starting the discharge lamp in order to improve the rise of the luminous flux immediately after starting the discharge lamp.

On the other hand, however, in order to make the circuit smaller, the instantaneous current supply capacity of the power supply device is minimized, and the output impedance of the power supply device, especially the magnetic circuit section, cannot be reduced to zero. Therefore, when a starting voltage is applied from the starting device and the discharge lamp shifts to arc discharge, current flows from both the starting device and the power supply device, and the lamp voltage rapidly decreases.

If the output impedance is kept small, a large current will flow out of the power supply and the output voltage of the power supply will drop significantly. As a result, once the starting voltage, for example, the pulse voltage, has stopped, the electric plate and discharge path will cool down because the lamp is in a critical state and the temperature of the arc tube has not yet risen. In this state, it is not easy to maintain arc discharge with only the output voltage of the power supply, and the lamp voltage increases.In contrast, the power supply cannot suddenly follow this, and the output voltage of the power supply at this time Means for solving the problem that a discharge lamp cannot be lit stably and is not easy to turn off when the lamp is lit alone a starting device connected to apply a starting voltage to the discharge lamp; and a control device connected to control the power supply device to have a period in which the output impedance is large and a period in which it is small at least during an output voltage application period of the starting device. This is based on a discharge lamp lighting device equipped with.

By having a period in which the output impedance of the power supply device is increased during the high voltage pulse application period when starting the discharge lamp, the starting current of the discharge lamp is temporarily suppressed and a drop in the output voltage of the power supply device is prevented.

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

FIG. 1 is a circuit diagram showing first and second embodiments of the discharge lamp lighting device of the present invention. In Fig. 1, 11 is a power supply device, 12 is a starting device 13, a discharge lamp, 30, 36
is a variable control device.

Power supply device 11t: DC power supply 16, which is a power supply with constant output voltage polarity, constant current push-pull inverter circuit 17
, a control circuit 26, and switch circuits 31 and 37, including a bias pull inverter circuit 171 & constant current inductance 18, transistors 19, 20, transformer 21, capacitors 22, 23, and inductance 2.
It consists of 4 and 25. 13 is a discharge lamp connected to the output end of the push-pull inverter circuit 17. 26 is a control circuit, transistors 19, 20
On/off control at a constant frequency. Reference numeral 12 denotes a starting device that applies a starting voltage to the discharge lamp 13, and is composed of a pulse transformer 27, a capacitor 28, and a starting circuit type A29. Enter the line into the discharge lamp 13
It is now time to start the pulse transformer 27 by outputting sufficient voltage from the secondary winding of the pulse transformer 27. The output voltage from the secondary winding of the pulse transformer 27 is applied to the discharge lamp 13 via the capacitor 28, and the discharge lamp 13 starts. 31
is a switch circuit connected in parallel to the inductance 24, and the transistor 32 is controlled by an output signal from a switch control circuit 30, which is a variable control device for the inductance component and is composed of transistors 32, 33 and diodes 34, 35, which are switch elements. , 33 are turned on and off. Further, 37 is a switch circuit connected in parallel to the capacitor 23, and the output from the switch control circuit 36, which is a variable control device for capacitance components, is composed of transistors 38, 39, which are switch elements, and diodes 40, 41. The signal causes transistor 38
, 39 are turned on and off.

7- The operation of the discharge lamp lighting device configured as above will be explained.

When the output of the DC power supply 16 is applied to the midpoint of the primary winding of the transformer 21 via the constant current inductance 18, the transistors 19 and 20 are alternately switched by the output of the control circuit 26.
A current flows through the primary winding of the transformer 21 and the transistors 19 and 20, and an AC voltage boosted according to the turns ratio of the secondary winding of the transformer 21 is output. Inductance components of the inductances 24, 25 and the secondary winding of the pulse transformer 27 (
This is the inductance for limiting the lamp current when the discharge lamp 13 is lit. Also capacitors 22, 23
is a capacitor for shaping the waveform of the output voltage generated in the secondary winding of the transformer 21, and is also used together with the inductance 18 to shape the waveform of the current flowing through the transistors 19 and 20. At the same time, capacitors 22, 23, 28, transformer 21, inductances 24, 25, and pulse transformer 27
It also contributes to resonance with the Resistor switch circuits 31, 37
The oscillation frequency of the control circuit 2-8=6 when is fully conductive is made to match the resonance frequency of the power supply device 11 when the discharge lamp 13 is the load. Also
The oscillation frequency of the control circuit 26 when the switch circuits 31 and 37 are completely non-conductive is made to match the resonant frequency of the power supply device 11 when the discharge lamp 13 is in the warm state. In addition, when the switch circuit 31 and the switch circuit 37 are completely conductive, the resonance frequency of the power supply device 11 and the oscillation frequency of the control circuit 26 when the discharge lamp 13 is the load match, so that the two of the transformer 21 A sinusoidal AC voltage is output to the secondary winding, and the current is limited by the base inductance of the inductances 24 and 25 and the inductance component of the secondary winding of the pulse transformer 27, so that the discharge lamp 13 remains lit.

Furthermore, when the switch circuit 31 and the switch circuit 37 are completely non-conductive, the resonance frequency of the power supply device 11 and the oscillation frequency of the control circuit 26 match when the discharge lamp 13 is loaded, so that the secondary of the transformer 21 A sinusoidal AC voltage is output to the windings, and the current is limited by the inductances 24, 25 and the bottom inductance of the secondary winding inductance component of the pulse transformer 27q-, so that the discharge lamp 13 remains lit.

When power is supplied to a discharge lamp lighting device like this configuration,
At the same time as the output voltage of the power supply device 11 increases, power is also supplied to the starter device 12. At this time, use the starting device ■2 (to start the discharge lamp 13).
A high voltage pulse necessary for breakdown between the main electrodes 3 is generated and applied to the discharge lamp 13. At this time, as shown in FIG. 2, the variable control device 30 controls the switch circuit 31 connected in parallel to the inductance 24 at least during the output voltage application period of the starting device 12, so that the switch circuit 31 is controlled to control a portion of the half cycle in terms of time. Then, the switch circuit 31 is brought into conduction. Thereby, the relative impedance of the inductance 24 is increased, and the output impedance of the power supply device 11 is made larger than that of the fully conductive state of the switch circuit 31. The resistor switch circuit 31 is opened.
Lamp current flows through inductances 24 and 25 1
0=, the discharge lamp 13 shall be lit at the rated lamp current. As described above, even if the output impedance of the power supply device 11 cannot be reduced to zero, at least the starting device II
During the output voltage application period, the voltage drop of the power supply device 11 is reduced by suppressing the lamp current, so that the power supply device 11 can supply the voltage necessary to maintain the discharge of the discharge lamp 13 when it is cold.

Therefore, the problem of difficulty in starting the discharge lamp 3 due to insufficient voltage to be supplied to the discharge lamp 13 or the problem of the lamp going out immediately after starting can be solved, and a stable starting condition can be ensured. The output voltage application period of the resistor starter 12 is very short, and in this embodiment (
When the output voltage application of the starter device 12 stops, the power supply device 1
The output state of the discharge lamp 13 is controlled to restore the output state to a state where a large output current can flow. You can do it like this. As described above, it is possible to provide a discharge lamp lighting device that ensures a stable starting condition and improves the rise of the luminous flux of the discharge lamp 13 immediately after starting.
Since the current supply capacity of the power supply device 11 can be reduced, the lighting installation can be made smaller. In this embodiment, the relative impedance of the inductance 24, which is a current limiting element of the push-pull inverter 17 constituting the power supply device 11, is used as a means for suppressing the lamp current at least during the output voltage application period of the starting device 12. In order to set the output state of the power supply device 11 to a state where the output current is smaller than the state at the maximum starting current of the discharge lamp 13, the output impedance of the power supply device 11 is increased. Any other structure may be used as long as it has a control function.For example, as shown in FIG.
By manipulating the relative impedance of this inductance 42, the output impedance of the power supply device 11 may be controlled. Here, the inductance 42 is a current-limiting element connected in series to the discharge lamp 13, and the on/off operation of the triac 43, which is a switch element connected in parallel to the inductance 42, causes the current limit to change in the middle of a half cycle. The output impedance of the push-pull inverter circuit 17 is changed by manipulating the relative impedance of the inductance 42 by turning on the triac 43 at or the like. Note that 441 is a control device that is connected to the gate terminal of the triac 43 and turns the triac 43 on and off. That is, at least during the output voltage application period of the starter 12, the controller 44 controls the triac 43 connected in parallel to the inductance 42, which is a current limiting element that changes the output impedance of the push-pull inverter circuit 17 constituting the power supply 11. Open inductance 24, 25, 4
By passing a lamp current through 2, the power supply 11
Increase the output impedance of At this time (Yo)
Triac 43 conducts, inductance 24, 25
, when the lamp current flows through the triac 43,
It is assumed that the discharge lamp 13 is lit at the rated lamp current. In addition, as a current limiting element for controlling the output impedance of the power supply 11 (not only inductance as in this embodiment, but also a resistor, capacitor, etc.), as long as it has the effect of current limiting the lamp current. Moreover, as for the method of controlling the relative impedance value of the current limiting element, in addition to the method using a triac as in this embodiment, for example, a relay or the like may be used (also, a triac (
During the application of the starting voltage, the power supply unit 11 may be kept completely off.
It is also possible to use a power exchanger configured with a high-frequency inverter, such as a DC-DC converter, which can obtain the same effect.Next, a third embodiment of the discharge lamp lighting device according to the present invention will be described. The configuration of the discharge lamp lighting device for realizing this embodiment is the same as that of the first embodiment of the present invention. (As shown in FIG. 2, at the beginning of the output voltage application period of the starting device 12 by the variable control device 30,
The switch circuit 3 controls only a part of the half cycle in terms of time.
1 is made conductive and the relative impedance of the inductance 24 is increased, thereby making the output impedance of the power supply device 11 larger than when the switch circuit 31 is completely conductive. Then, in the middle of the output voltage application period of the starting device 12, the output impedance of the power supply device 11 is controlled to be smaller than the state when the discharge lamp 13 is lit at its rated value. When electric power is supplied to the discharge lamp lighting device having such a configuration, a high voltage pulse is applied from the starting device 12 to the discharge lamp I3, and the basic operation until the discharge lamp 13 starts and lights up (in accordance with the present invention) is as follows. This is similar to the first embodiment of the discharge lamp lighting device.In this embodiment, as shown in FIG. 2, the period during which the lamp current is suppressed at startup is shorter than in the first embodiment of the present invention.1. In the middle of the output voltage application period of the starter 12, the power supplied to the discharge lamp 13 becomes larger than the rated lighting state of the discharge lamp 13. Therefore, immediately after starting the discharge lamp 13, The energy that can be supplied to the discharge lamp 13 increases, and the first aspect of the present invention
The luminous flux of the discharge lamp I3 can be started up better than in the case of the discharge lamp lighting device according to the embodiment. Also, since the lamp current is initially suppressed, the discharge lamp 1
At the initial stage when the temperature of the arc tube 3 does not rise (y), the push-pull inverter circuit 17 outputs a slightly higher output voltage, which is necessary to maintain the active discharge of the discharge lamp 13, to maintain the discharge, and at the same time the temperature of the arc tube rises. By making it possible to draw a large amount of current from the middle stage, the arc discharge of the discharge lamp 13 can be maintained even if the output voltage of the push-pull inverter circuit 17 decreases to some extent. It is possible to provide a discharge lamp lighting device that improves the rise of the luminous flux of the discharge lamp 3 immediately after starting while ensuring that the luminous flux of the discharge lamp 3 is increased immediately after starting. By connecting an inductance 42 in series with the inductance 24, which is the current limiting element of the push-pull inverter circuit 17 that constitutes the power supply device 11, and manipulating the relative impedance of this inductance 42,
It may be possible to control the output impedance of the power supply device 11N
.

Next, a fourth embodiment of the discharge lamp lighting device according to the present invention will be described. The configuration of the discharge lamp lighting device for realizing this embodiment is the same as that of the first embodiment of the present invention. The difference from the first embodiment is the control system, and in this embodiment, the input power to the discharge lamp 13 is changed during the output voltage application period of the starter 12.
The output impedance of the power supply device 11 and the output state of the starter device 12 are controlled such that the output impedance of the power supply device 11 and the output state of the starter device 12 are set to a larger value that is less than or equal to the allowable limit value. One way to improve the starting performance of a discharge lamp is to increase the input power supplied to the discharge lamp at the time of starting the lamp compared to the time of rated lighting. In other words, a starting current larger than the rated lamp current is supplied to the discharge lamp at the time of starting, so that the luminous flux starts up quickly. However, discharge lamps have a unique input power capacity that is determined by the shape of the arc tube, the structure of the electrodes7, the mK of the substance sealed in the arc tube, and its gas pressure, and excessive force beyond this limit may cause the lamp to malfunction or break. bring. In this embodiment, the output impedance input of the power supply device 11 and the output state of the starter device 12 are controlled in order to maximize the starting performance while preventing excessive force that would cause abnormal lighting of the lamp. As a result,
While preventing a drop in the output voltage of the power supply device 11, it is possible to supply the maximum starting power to the discharge lamp 13 without causing any abnormality in the lighting of the discharge lamp 13. The luminous flux of the discharge lamp 3 can be started up better than in the case of the discharge lamp lighting device according to the first embodiment. As described above, it is possible to provide a discharge lamp lighting device that improves the rise of the luminous flux of the discharge lamp 13 immediately after starting while ensuring a stable and safe starting condition.

Next, a fifth embodiment of the discharge lamp lighting device according to the present invention will be described. In order to realize this embodiment, the configuration of the discharge lamp lighting device 8 is the same as that of the first embodiment of the present invention. What is different from the first embodiment?
In this embodiment, during the application period of the output voltage of the starting device 12, when a high voltage pulse, which is the output voltage of the starting device 12, is applied (not shown in FIG. 2), the variable control device 30 The switch circuit 31 connected in parallel to the inductance 24 is controlled, and the switch circuit 31 is rendered conductive for only a portion of a half period in time.As a result, the relative impedance of the inductance 24 is increased, and the output of the power supply 11 is increased. The impedance is made larger than when the switch circuit 31 is fully conductive.Then, while the output high-voltage pulse voltage of the starter 12 is stopped, the output impedance of the power supply 11 is made smaller than when the output voltage of the starter 12 is applied. control, i.e.
During the output voltage application period of the starting device 12, when a large starting current flows, the output voltage of the push-pull inverter circuit 17 decreases.
3o controls the switch circuit 31 connected in parallel to the inductance 24, and makes the switch circuit 31 conductive for only a portion of a half cycle in terms of time. This increases the relative impedance of the inductance 24 and makes the output impedance of the power supply 11 larger than the fully conductive state of the switch circuit 31. The impedance is controlled to be larger than when the output voltage of the starting device 12 is applied.In other words, when a high voltage pulse is applied, the output current of the power supply device 11 is increased, and the power input to the arc tube of the discharge lamp 13 is controlled by the high voltage pulse. The electric power of the discharge lamp 13 is also increased to raise the temperature of the arc tube more rapidly.At this time, since a high voltage pulse is applied to the discharge lamp 13, the discharge state of the discharge lamp 13 is stable and the arc discharge is prevented. Next, when no high voltage pulse is applied, the only input to the discharge lamp 13 is the current from the power supply 11, and at the beginning of the starting voltage application period, the discharge sustaining voltage of the discharge lamp 13 is The push-pull inverter circuit 1
7. The rate of increase in the output voltage due to the decrease in the output current can be made greater than the rate of increase in the discharge sustaining voltage of the discharge lamp 13. On the other hand, the blown discharge lamp 13 can maintain discharge. This causes unstable lighting of the discharge lamp 13.
It is possible to provide a discharge lamp lighting device which can start up a luminous flux more quickly than the discharge lamp lighting devices according to the first and fourth embodiments of the present invention while preventing the lamp from going out.

Next, a sixth embodiment of the discharge lamp lighting device according to the present invention is shown in FIG. I'o In FIG. 4, 11 is a power supply device, 12 is a starting device, 13 is a discharge lamp, 30
, 36 is a variable control device, and 48 is a detection device, and these connections except for the detection device 48 are the same as in the first embodiment of the discharge lamp lighting device of the present invention.

When power is supplied to the discharge lamp lighting device having such a configuration, a high voltage pulse is applied from the starting device 12 to the discharge lamp 13, and the discharge lamp 13 starts 21. The basic operation C until the discharge lamp 13 lights up is as follows: This is similar to the first embodiment of the discharge lamp lighting device in .

A detection device 48 is installed to detect the light output, which is a lamp characteristic of the discharge lamp 13. In this embodiment, the detection device 48 detects the light output of the discharge lamp 13 in a non-contact manner. A variable control device 3 connected in parallel to an inductance 24 which is a current limiting element.
Connected to 0.

Based on the detection signal of the detection device 48, the variable control device 30 determines that when the discharge lamp 13 is sufficiently arc discharged to a predetermined level or higher, the light output becomes strong, and the output of the detection device 48 also becomes strong. The variable control device 30 is operated to control the output impedance of the power supply device 11 to be small.Furthermore, when the high voltage pulse stops, the arc discharge sustaining voltage increases, and the optical output weakens,
The variable control device 30 is controlled so that the output impedance of the power supply device 11 is high. By detecting the light output, which is a lamp characteristic of the discharge lamp 13, in this way, the state of the lamp can be determined more reliably than in the case of the discharge lamp lighting devices according to the first to 22-5 embodiments of the present invention. This makes it possible to control the luminous flux of the discharge lamp 13 while preventing unstable lighting or turning off of the discharge lamp 13 caused by a drop in the output voltage of the power supply 11. It can be made good.

Therefore, this makes it possible to provide a discharge lamp lighting device that ensures a stable starting condition and improves the rise of the luminous flux of the discharge lamp 13 immediately after starting. In this embodiment, the force used to detect light may be any other force as long as it is related to lamp characteristics, such as lamp voltage or lamp current. Further, in the first to sixth embodiments described above, a transistor UFET or other switching element may be used.

Furthermore, the same applies to other inverters such as inverters (Dai-Shi inverters), as well as starter devices (which apply high-voltage pulses and high-frequency voltages).

Effects of the Invention As described above, the present invention temporarily suppresses the lamp current during the voltage application period, and the output voltage of the power supply device decreases, making it difficult to start the discharge lamp. The solution to this problem is to start the discharge lamp stably,
It is possible to provide a discharge lamp lighting device that improves the start-up of luminous flux.

[Brief explanation of drawings]

FIG. 1 shows the circuit of the discharge lamp lighting device according to the first and second embodiments of the present invention.
The electrical characteristics at the initial stage of startup in the examples from to the fifth are as follows:
Fig. 3 shows the circuit of the discharge lamp lighting device in another tank bottom according to the first embodiment of the present invention; Fig. 4 shows the circuit of the discharge lamp lighting device in the sixth embodiment of the invention; and Fig. 5 shows the conventional circuit. FIG. 2 is a circuit diagram of a discharge lamp lighting device of FIG. 11... Power supply device 12... Starting device 13... Discharge lamp, 30, 36... Variable control device, 48...
・Detection device

Claims (6)

[Claims] (1) A discharge lamp, a power supply device with variable output impedance connected to turn on the discharge lamp, and a starting device connected to apply a starting voltage to the discharge lamp, at least during the application period of the output voltage of the starting device. A discharge lamp lighting device comprising: a control device connected so as to control the power supply device having a period in which the output impedance is high and a period in which the output impedance is low. (2) A discharge lamp, a variable output impedance power supply device connected to turn on the discharge lamp, a starting device connected to apply a starting voltage to the discharge lamp, and the end of the output voltage application period of the starting device. A discharge lamp lighting device comprising a control device that controls the output impedance of a power supply device to be smaller than the rated lighting state of the discharge lamp. (3) The discharge lamp lighting device according to claim 1, wherein the output impedance of the power supply device is controlled to be smaller than the state during rated lighting of the discharge lamp during the output voltage application period of the starter device. (4) A patent claim in which the output impedance of the power supply device and the output state of the starter device are controlled so that the input power to the discharge lamp becomes a value larger than the allowable limit value of the discharge lamp during the application period of the output voltage of the starter device. The first term of the range,
Discharge lamp lighting device according to paragraph 2 or 3 (5) Claims 1 or 4 in which the output impedance of the power supply device is controlled so as to be in a higher state during the output voltage stop period than when the output voltage of the starter device is applied during the output voltage application period of the starter device. Discharge lamp lighting device as described in Section 1. (6) a detection device that detects characteristics related to lamp characteristics;
Claims 1 to 5 further include a control device connected to control the output impedance of the power supply device to be small while the discharge lamp is arcing at a predetermined level or higher based on a signal from the detection device. The discharge lamp lighting device described in items 5 and up.