JP2002299089A - Discharge lamp lighting device and luminaire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problems, when electrodes at both ends of a discharge tube to a small-tube diameter and wires connecting the electrodes to a lighting device are sealed in closely, a contact made in slender discharge tube of the electrode and the wire due to vibrations during manufacture or transfer disables given power supply and heating to the electrode to cause early blackening phenomenon, and develops a layer short circuit state of a filament to cause an abnormal temperature increase in a heating transformer. SOLUTION: A discharge lamp lighting device and a luminaire comprise a rectifying circuit 4 for rectifying and smoothing commercial alternating current power into direct current power; FETs 9 and 10 of an inverter circuit for converting the direct current power generated by the rectifying circuit 4 into high-frequency power, to supply it to the filament of the discharge lamp; filament voltage and current detecting circuits 16 and 17, a multiplication circuit 18 and a comparison circuit 19 all constituting a short circuit detecting circuit for detecting filament short circuiting of the discharge lamp; and a control circuit 20 for controlling or stopping the operation of the inverter circuit, when the short circuit detecting circuit detects a filament short circuiting.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting device for a discharge lamp such as a fluorescent lamp, and a lighting fixture using the lighting device.

[0002]

2. Description of the Related Art Lighting control of a discharge lamp such as a fluorescent lamp needs to be started immediately from a glow discharge to an arc discharge region. For this reason, the electrode is preheated in order to facilitate electron emission from the electrode, or a voltage higher than a voltage required for maintaining lighting is applied to the electrode at the time of starting in order to promote glow discharge.

[0003] A lighting device for controlling the lighting of this discharge lamp includes:
A low-frequency AC power supply, which is a commercial AC power supply, is rectified into DC by a rectifier circuit, the rectified DC power supply is smoothed and stabilized by a chopper circuit, and the smoothed stabilized DC power supply is converted to a high-frequency AC power supply by a high-frequency inverter. It is supplied to the filament electrode of the discharge lamp.

The high-frequency AC power supplied from the high-frequency inverter is turned on by resonance with a current-limiting inductor, a DC cut capacitor, and a pair of resonance capacitors provided in parallel with the filament of the discharge lamp.

[0005]

A conventional lighting device for a discharge lamp such as a fluorescent lamp is started and lit by a high-frequency AC power source generated by a high-frequency inverter. On the other hand, in recent years, the discharge tube of a discharge lamp has been reduced in diameter.

[0006] A discharge lamp having a reduced-diameter discharge tube has a filament electrode sealed at both ends thereof.
A pair of wires supporting the filament electrode is sealed.

[0007] Since the pair of wires are sealed in a state of approaching each other to reduce the diameter, the pair of wires are led out of the sealing portion by vibration during manufacturing or transportation. A phenomenon of contact occurs outside the discharge lamp.

When the discharge lamp in the state where the pair of wires are in contact with each other is controlled in this way, a predetermined power cannot be supplied to the electrodes, so that the filament cannot be heated to the predetermined state, and the discharge lamp cannot be heated. The problem of early blackening and the short-circuiting of the filament,
There has been a problem that the temperature of the transformer excessively increases.

The present invention has been made in view of the above problems, and detects the contact state between a pair of wires supporting a filament electrode, stops the supply of the high-frequency AC power, and protects the lighting device. The purpose is to aim.

[0010]

According to a first aspect of the present invention, there is provided a discharge lamp lighting device for rectifying and smoothing a commercial AC power supply into a DC power supply; and converting the DC power supply generated by the rectification means into a high-frequency power supply. Inverter means for supplying to the filament of the discharge lamp; short-circuit detection means for detecting a filament short-circuit in the discharge lamp; control means for stopping and controlling the operation of the inverter means when the short-circuit detection means detects a filament short-circuit. And;

In the present invention and the following inventions, the definitions and technical meanings of terms are as follows unless otherwise specified.

The rectifying means is a circuit for performing full-wave or half-wave rectification from alternating current to direct current. The DC rectified by the rectifier circuit is smoothed by a smoothing circuit using a smoothing capacitor or a chopper circuit using a switch element.

The inverter means is an inverter circuit for converting the DC power into a high-frequency AC power using a switching element. Stable light emission of the discharge lamp is maintained by the high-frequency power source generated by the inverter circuit.

The discharge lamp is a discharge lamp using a thin tube having a discharge tube inner diameter of 20 mm or less. In this capillary discharge lamp, a filament and a wire connecting the filament are installed close to each other. For this reason, the wires come into contact with each other due to vibration during the assembly and manufacture of the discharge lamp and during transportation and transportation.
If this wire contact occurs, an appropriate preheating current is not supplied to the filament, so that the filament cannot be heated and blackening occurs early, or the current for the filament preheating transformer increases, resulting in abnormal heat generation.

The mutual contact between the pair of wire wires is the same phenomenon as a short circuit of the filament.

Therefore, the short-circuit detecting means detects the short-circuit of the filament by detecting either the filament voltage or the current in the short-circuit detecting circuit for detecting the short-circuit of the filament of the discharge lamp.

The control means stops the drive of the inverter means when the short-circuit detection means detects a filament short-circuit.

Thus, when the wire of the thin tube discharge lamp is short-circuited due to vibration, the short-circuit detection circuit detects the short-circuit of the filament, and by detecting the short-circuit, the inverter circuit for supplying lighting power to the filament of the discharge lamp. Since the driving can be stopped, a short-circuit of the filament of the discharge tube can be detected at an early stage, and the excessive operation of the lighting circuit due to the short-circuit of the filament can be prevented, thereby preventing the deterioration of the electronic component element.

According to a second aspect of the present invention, in the discharge lamp lighting device according to the first aspect, the short-circuit detecting means includes a filament voltage detecting means for detecting a filament voltage of the discharge lamp; A comparison unit that compares the filament voltage detected by the detection unit with a predetermined reference value, and outputs a comparison result of the comparison unit to the control unit, and when the filament voltage is equal to or less than a predetermined reference value, the control unit The operation of the inverter means is stopped.

The filament voltage detecting means is a circuit for detecting a voltage applied to both ends of the filament of the discharge lamp, that is, a pair of wire lines supporting the filament.
The primary side of a voltage detecting transformer is connected to both ends of the filament, and the filament voltage generated on the secondary side of the transformer is rectified to obtain a voltage value.

The comparing means is a comparing circuit for comparing the voltage value obtained by the filament voltage detecting means with a reference voltage value of the filament.

That is, the filament voltage detected by the filament voltage detection means is compared with a filament reference voltage by comparison means. If the detected filament voltage is lower than the filament reference voltage, a short-circuit of the filament, ie, a pair of filaments supporting the filament, is detected. It is determined that the wire wire is short-circuited, and the control means stops the inverter means.

With this arrangement, the short circuit of the wire supporting the filament of the discharge tube can be easily detected by the value of the filament voltage, and the drive of the inverter circuit for supplying lighting power to the filament can be stopped. Excessive operation of the discharge tube lighting circuit can be prevented, and deterioration of electronic component elements constituting the lighting circuit can be prevented.

According to a third aspect of the present invention, in the discharge lamp lighting device according to the first aspect, the short-circuit detecting means includes a filament current detecting means for detecting a filament current of the discharge lamp; A comparison unit that compares the filament current detected by the detection unit with a predetermined reference value, and outputs a comparison result of the comparison unit to the control unit.When the filament current is equal to or less than a predetermined reference value, the control unit The operation of the inverter means is stopped.

The filament current detecting means is a circuit for detecting a current applied to a pair of filaments of the discharge lamp. A primary side of a current detecting transformer is connected between the pair of filaments. The current value is obtained by rectifying the filament current generated on the side.

The comparing means is a comparing circuit for comparing the current value obtained by the filament current detecting means with the reference current value of the filament.

That is, the filament current detected by the filament current detection means is compared with a filament reference current by comparison means. If the detected filament current is higher than the filament reference current, the filament, ie, a pair of wire lines supporting the filament, Is determined to be short-circuited, and the control means stops the inverter means.

Thus, a short circuit of the wire supporting the filament of the discharge tube can be easily detected by the value of the filament current, and the drive of the inverter circuit for supplying lighting power to the filament can be stopped. Excessive operation of the discharge lamp lighting circuit can be prevented, and deterioration of electronic component elements constituting the lighting circuit can be prevented.

According to a fourth aspect of the present invention, in the discharge lamp lighting device according to the first aspect, the short-circuit detecting means includes a filament voltage detecting means for detecting a filament voltage of the discharge lamp, and a filament current detecting means. A filament current detecting means for detecting, a filament power based on the filament voltage and current detected by the filament voltage and current detecting means, a power calculating means, and a filament power determined by the power calculating means as a predetermined reference value Comparing means for outputting the result of the comparison to the control means, and stopping the operation of the inverter means by the control means when the filament power is equal to or less than a predetermined reference value. .

The means for detecting the voltage and current of the filament are as follows:
A circuit for detecting a voltage and a current applied to a pair of ends of a filament of the discharge lamp.

The primary voltage of the transformer is connected to both ends of a pair of filaments, and the filament voltage generated on the secondary side of the transformer is rectified to obtain a voltage value.

The filament current is connected to the primary side of a transformer for current detection between a pair of filaments.
Find the current value.

Using the voltage and current values detected by the filament voltage and current detection means, a power value is calculated by a multiplication circuit as power calculation means.

The comparing means is a comparing circuit for comparing the power value calculated by the multiplying circuit based on the voltage and current values obtained by the filament voltage and current detecting means with the reference power value of the filament.

That is, a power value is calculated based on the filament voltage and current detected by the filament voltage and current detection means, and the calculated power value is compared with a filament reference power value by comparison means. If the filament power is lower than the filament reference power, it is determined that the filament, that is, a pair of wire lines supporting the filament, is short-circuited, and the control means stops the inverter means.

When the filament of the discharge tube is short-circuited,
In some cases, a change in the filament voltage or current cannot be determined due to the resistance of the wire wire or the like. In particular, when the temperature of the wire increases due to the heat in the discharge tube, the resistance increases. Further, when the filament is heated at a constant current, the filament current may not change when the filament is short-circuited.

In this case, by detecting the filament voltage and the current, the accuracy of detecting a filament short circuit is improved.

According to a fifth aspect of the present invention, in the discharge lamp lighting device according to the first aspect, the short-circuit detecting means detects a voltage and a current for detecting a filament voltage value and a current value of the discharge lamp. Detecting means, and a window comparator means for determining an upper limit value of the filament voltage value and the current value detected by the voltage and current detecting means, and the upper limit value of the filament voltage value and the current value is determined by the window comparator means. When the value exceeds the value, it is determined that the end of the life of the discharge lamp is determined, and the drive of the control unit is controlled to stop the operation of the inverter unit.

The window comparator means is a circuit for judging and comparing the filament voltage detected by the filament voltage and current detecting means with the upper limit of the current value.

On the other hand, at the end of the life of the discharge tube, the filament voltage and current increase. Therefore, it is possible to know the end of the life of the discharge tube by judging and comparing the filament voltage and the upper limit value of the current.

Thus, the operation of the lighting device can be stopped at the end of the life of the discharge tube, and unnecessary operation of the lighting device at the end of the discharge lamp can be stopped.

A discharge lamp lighting device according to a sixth aspect of the present invention is the discharge lamp lighting device according to any one of the second to fifth aspects, wherein the filament voltage value and the current value of the discharge lamp are compared by the comparing means of the short-circuit detecting means. The reference value to be compared is changed according to the dimming control of the discharge lamp.

In the dimming control of the discharge lamp, all the discharge lamps (10
At 0% emission, the lamp current is large and the filament voltage is low. Also, the light is dimmed from all the lights, for example, 2
When the lamp is turned on at 0%, the lamp current is reduced, but the filament voltage is increased in order to maintain the filament electrode at a predetermined heating temperature.

In the lighting device for performing such dimming control, when the filament short-circuit judgment of the discharge tube is performed by the comparing means using the filament voltage and current detected by the filament voltage and current detecting means, the discharge is performed. An erroneous determination may be made depending on the dimming state of the lamp.

For this reason, by changing and setting the reference power value of the comparing means in accordance with the dimming control, the accuracy of the filament short-circuit determination at the time of the dimming control is improved.

The lighting fixture of the invention according to claim 7 includes a discharge lamp;
The discharge lamp lighting device according to any one of claims 1 to 6, which controls lighting of the discharge lamp.

The lighting fixture includes a pair of sockets mounted on a pair of terminals connected to a pair of filaments of the discharge lamp by lead wires, and the discharge lamp lighting device for supplying lighting power to the socket. It comprises a reflector or the like for reflecting the illumination light emitted from the discharge lamp.

By incorporating the discharge lamp lighting device into the lighting fixture, the lighting device can be prevented from being damaged when the filament of the discharge lamp mounted on the lighting fixture is short-circuited, and a long-life lighting fixture can be provided.

[0049]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing the overall configuration of a discharge lamp lighting device according to the present invention, and FIG.
It is a connection diagram showing a discharge lamp filament short circuit detection circuit in a discharge lamp lighting device concerning the present invention.

The overall configuration of the discharge lamp lighting device will be described with reference to FIG. The low-frequency commercial AC power supply 1 is supplied to a rectifier circuit 4 via a high-frequency noise removal circuit including an inductance 2 and a capacitor 3.

The drain of the FET 6 and the anode of the diode 7 are connected to one output terminal of the rectifier circuit 4 via the inductance 5, and the source of the FET 6 is connected to the other output terminal (reference terminal). Have been. The DC power rectified by the rectifier circuit 4 is supplied through the inductance 5 between the drain and the source of the FET 6. The FET 6 constitutes a chopper circuit for smoothing and stabilizing the DC rectified by the rectifier circuit 4 with a switching element.

An electrolytic capacitor 8 is connected between the cathode of the diode 7 and a reference end. In parallel with the electrolytic capacitor 8, a switching element FET9,
10 are connected in reverse series. The sources of the FETs 9 and 10 include a capacitor 11, a preheating transformer 12, one filament 13a of a discharge lamp 13, a resonance capacitor 1
4. The discharge lamp 13 is connected to the reference end through a series circuit of the other filament 13b.

That is, the switching element FE
This is an inverter circuit that generates high-frequency AC power by performing high-frequency switching operation on T9 and T10. The high-frequency AC power generated by this inverter circuit is
And the filaments 13a, 1 via the preheating transformer 12
3b. At this time, the filaments 13a and 13b of the discharge lamp 13 are operated by the resonance operation of the resonance capacitor 14.
Is supplied with starting power and lighting maintenance power.

The filaments 13a, 1 of the discharge lamp 13
3b to detect the voltage and current of the filament 13b.
b, a filament voltage detection circuit 16 is connected to both ends,
Further, an inductance 15 for detecting a filament current is provided between the filament 13b and the resonance capacitor 14.
The output of the inductance 15 is supplied to a filament current detection circuit 17.

The filament voltage detection circuit 16 and the filament current detection circuit 17 determine the detected filament voltage and current value, respectively. The voltage value and the current value obtained by the filament voltage detection circuit 16 and the filament current detection circuit 17 are output to a multiplication circuit 18.

The multiplication circuit 18 calculates a power value from the supplied voltage value and current value, and outputs the calculated power value to the comparison circuit 19. The comparison circuit 19 compares the power value of the multiplication circuit 18 with a reference power value. The comparison with the reference power value of the comparison circuit 19 is performed by comparing the filaments 13a,
When 13b is short-circuited, the filament voltage and current are converted. Therefore, when the filament power value is equal to or less than the predetermined reference power value, the filaments 13a and 13b
Can be determined as any of the short circuits.

Therefore, the filament voltage detection circuit 1
6 and the filament power calculated by the multiplication circuit 18 based on the voltage and current detected by the filament current detection circuit 17,
When the comparison circuit 19 determines that the power is lower than the reference power, the comparison circuit 19 outputs the determination result to the control circuit 20.

The control circuit 20 controls the drive of the FETs 9 and 10 constituting the inverter circuit and the drive of the FET 6 of the chopper circuit.

That is, the voltage and current of the filaments 13a and 13b of the discharge lamp 13 are detected, and the filament 1
When 3a and 13b are short-circuited, the filament voltage and current change. The change in the filament voltage and current is compared with a reference value to determine whether the filament is short-circuited. When it is determined that the filament is short-circuited, the control circuit 20 controls the inverter circuit and the chopper circuit to stop driving.

Thus, abnormal heating of the inverter circuit and the heating transformer 12 due to the filament short of the discharge lamp 13 can be prevented.

Next, a specific method for detecting the filament voltage and the current will be described with reference to FIG. The preheating transformer 12 is connected to one filament 13a of the discharge lamp 13, and the other end 13b is connected to the reference end.

One filament 13 of the discharge lamp 13
a, the first filament voltage detection circuit 16a
Is provided. The first filament voltage detection circuit 16a is connected to a primary side of a first transformer 21a for voltage detection, and to a secondary side of the first transformer 21a,
The rectifier circuit 22a is connected. This rectifier circuit 22a
Is connected to a parallel circuit of a capacitor 23a and a resistor 24a.
Is connected to one terminal of a multiplication circuit 18a.

A second filament voltage detecting circuit 16b is provided at both ends of the other filament 13b of the discharge lamp 13. The second filament voltage detection circuit 16b includes a second transformer 21b for detecting a voltage.
And a rectifier circuit 22b is connected to a secondary side of the second transformer 21b. The output of the rectifier circuit 22b is connected to a parallel circuit of a capacitor 23b and a resistor 24b, and the output of the parallel circuit of the capacitor 23b and the resistor 24b is connected to one terminal of a multiplying circuit 18b.

Further, a filament current detecting circuit 1 is connected in series with a resonance capacitor 14 between one filament 13a and the other filament 13b of the discharge lamp 13.
7 are provided. This filament current detection circuit 1
7, a primary side of a third transformer 25 for current detection is connected between the resonance capacitor 14 and the filament 13b. A rectifier circuit 26 is connected to the secondary side of the third transformer 25. The output of the rectifier circuit 26 includes:
A parallel circuit of a capacitor 27 and a resistor 28 is connected, and the other terminal of the multiplying circuits 18a and 18b is connected to the output of the parallel circuit of the capacitor 27 and the resistor 28.

That is, the first and second transformers 21a, 21a,
At 21b, the voltages of the filaments 13a and 13b are detected. The filament voltage detected by the first and second transformers 21a and 21b is rectified by rectifier circuits 22a and 22b, respectively, and the capacitors 23a and 23b and the resistor 2
At 4a and 24b, it is converted into a DC voltage value. This DC voltage value is output to multiplication circuits 18a and 18b, respectively.

On the other hand, in the third transformer 25, the filament current of the discharge tube 13 is detected, the detected filament current is rectified into DC by the rectifier circuit 26, and converted to DC voltage value by the capacitor 27 and the resistor 28. You. This DC voltage value is output to multiplication circuits 18a and 18b, respectively.

The multiplying circuit 18a is connected to the filament 1
The power value is calculated by multiplying the voltage value from the first filament voltage detection circuit 16a for detecting the voltage of 3a by the filament current value from the filament current detection circuit 17.

The power value calculated by the multiplying circuit 18a is output to a comparing circuit 19a, and is compared with a reference power value by the comparing circuit 19a. This comparison circuit 19a
It is determined whether the power value output from the multiplication circuit 18a is equal to or greater than the reference power value, and a determination result signal is output to the control circuit 20.

The control circuit 20 generates a signal Q for controlling the driving of the FETs 9 and 10, which are the switching elements of the inverter circuit, based on the determination result signal from the comparison circuit 19a.
1, Q2 are generated and output.

That is, when the power value of the filament 13a is equal to or more than the reference power value, it is determined that the filament 13a is in a normal state.
Control is performed to operate the inverter circuit normally. If the power value is equal to or less than the reference power value, the filament 13a
Is determined to be short-circuited, and the control circuit 20 performs control to stop the operation of the inverter circuit.

The multiplication circuit 18b and the comparison circuit 19b are the same as the multiplication circuit 18a and the comparison circuit 19a.
Since the operation is the same as that described above, the description is omitted.

Accordingly, the filament 13 of the discharge tube 13
When any one of a and 13b is short-circuited, the short-circuit is immediately detected, and the operation of the inverter circuit can be stopped. This makes it possible to use the filament discharge lamp as a lighting device for a capillary discharge lamp in which vibration is likely to cause a short circuit.

In the above-described embodiment, the voltages and currents of the filaments 13a and 13b of the discharge lamp 13 are detected, and
Although the short circuit of the filament is determined, the short circuit can be determined only by the filament voltage or the filament current.

However, when only the filament voltage is detected and the detected voltage is compared with the reference voltage value, the resistance of the lead wire for supplying power to the filaments 13a and 13b of the discharge lamp 13 fluctuates due to heat. In some cases, an erroneous determination may be made that the temperature inside the discharge lamp 13 is rising. For this reason, it is necessary to consider the fluctuation of the resistance of the lead wire for supplying power to the filaments 13a and 13b.

Further, when only the filament current is detected and the detected current is compared with the reference current value, when the filaments 13a and 13b of the discharge lamp 13 are short-circuited, the change in the filament current becomes very small. In addition, it is necessary to provide a detection circuit capable of minute current detection.

The discharge lamp lighting device is intended to protect the lighting device by detecting a filament short-circuit of the thin tube discharge lamp. However, the discharge lamp has a life, and in general, the discharge lamp becomes black, Alternatively, the end of life is recognized only after the lighting stops, but if the discharge lamp continues to be operated after the end of life, the lighting device is destroyed.

The protection of the lighting device at the end of the life of the discharge lamp will be described with reference to FIG. A window comparator 29 shown in FIG. 3A is used in place of the comparison circuits 19a and 19b. One terminal of the window comparator 29 is connected to the multiplication circuits 18a and 18a.
b, and the reference power is supplied to the other terminal.

The window comparator 29 is provided in the
As shown in (b), the upper limit consisting of the width of the filament power and the height of the power is monitored. If this power value exceeds the reference upper limit, it is determined that the discharge lamp 13 is at the end of its life.
The control for stopping the driving of No. 10 is performed.

As a result, the lighting power supply from the lighting device at the end of the life of the discharge lamp 13 is stopped, and the destruction of the lighting device can be prevented.

The lighting device of the discharge lamp may be used in combination with a light control device. Detection of short-circuit of the discharge lamp in the discharge lamp lighting device combined with the dimmer will be described with reference to FIGS. 4 and 5. FIG. 4 is similar to FIG.
The same parts as those described above are denoted by the same reference numerals, and detailed description is omitted.

As shown in FIG. 4, the dimming of the discharge lamp 13 is
Based on the dimming signal from the dimming device 32, the control circuit 20
Light is controlled by controlling the switch element 6 of the chopper circuit and the switch elements 9 and 10 of the inverter circuit to control and adjust the filament voltage and current supplied to the discharge lamp 13.

Based on the light control signal from the light control device 32,
Reference power sources 31a, 31 of the comparison circuits 19a, 19b
By setting the power value V1 of b in accordance with the dimming state, it is possible to detect a short circuit of the discharge lamp 13 during dimming.

The relationship between the lamp current supplied to the discharge lamp 13 and the filament voltage at the time of dimming, as shown in FIG. 5, is that when the discharge lamp 13 is fully lit, the lamp current is large and the filament voltage is Become smaller. When the discharge lamp 13 is dimmed, the filament voltage increases as the lamp current decreases.

Therefore, the reference power supplies 31a, 3a of the comparison circuits 19a, 19b are changed according to the change of the lamp current at the time of dimming.
By varying the reference power value V1 of 1b, short-circuit detection of the discharge lamp 13 at the time of dimming can be detected, and if the discharge lamp 13 is short-circuited, the drive of the inverter circuit can be stopped from the control circuit 20. Become. Thereby, even if the lamp current and the filament voltage at the time of dimming change, the filament short circuit can be detected, the operation of the inverter circuit can be stopped, and the lighting device can be prevented from being damaged.

Next, after the supply of the commercial AC power supply 1 supplied to the discharge lamp lighting device is stopped and the discharge lamp is turned off, the commercial AC power supply is supplied again to restart the discharge lamp. The lighting device will be described with reference to FIGS. In the case where the supply of the commercial AC power supply 1 is stopped instantaneously and the power supply is re-supplied immediately, the power supply is turned on again after the discharge lamp is turned off and the filament is not sufficiently cooled. This is a restart method at the moment of a power failure.

Generally, the lamp characteristics of the discharge lamp 13 and the output characteristics of the inverter circuit of the lighting device are as shown in FIG.
Assuming that the horizontal axis is current and the vertical axis is voltage, the lamp characteristics of the discharge lamp 13 show the characteristics shown by B in the drawing, and the output characteristics of the inverter circuit have the characteristics shown by A in the drawing. The output characteristic A of the inverter circuit is converted from the characteristic A into A1 and A2 when the frequency decreases. A point a0 in the figure is a voltage value when the load of the inverter circuit is in an open state (the discharge lamp 13 is not mounted), and a point b in the figure is a voltage / current value at the time of rated lighting of the discharge lamp 13. The point c in the figure is the current value when the load is short-circuited (filament short-circuit of the discharge lamp 13).

With such lamp characteristics and inverter characteristics, a lighting device that performs complicated control such as lighting control or dimming control of a discharge lamp having a small tube diameter, for example, immediately returns to lighting by starting dimming or momentary power failure. When the separate excitation control is performed by the inverter circuit requiring the function, the amount of change in the impedance immediately after the start of the discharge lamp is large, and the operation may be performed at the lowest frequency outside the feedback control. This tendency is particularly remarkable in a discharge lamp having a small tube diameter.

When the dimming is started at the lowest frequency by the separate excitation control or when the lighting is restored after an instantaneous power failure, the discharge lamp is set to be at least 1.8 times the voltage VL of the rated lighting voltage / current value b of the discharge lamp. It has been found through experiments that the lighting can be restored.

Generally, the lighting voltage at the start of the discharge lamp is 2.8 times the rated lighting voltage VL. However, at the time of an instantaneous power failure, the filament of the discharge lamp is sufficiently preheated. The lighting voltage is 1.8 times the lighting voltage VL, so that re-lighting can be quickly performed, and the life of the lighting device can be extended without giving unnecessary operation to the electronic components of the lighting device.

Next, a lighting device having lighting return control means after an instantaneous power failure will be described with reference to FIG. The same parts as those in FIG. 1 are denoted by the same reference numerals, and detailed description is omitted.

A connection point between one of the filaments 13a of the discharge lamp 13 and the resonance capacitor 14 is connected to a lighting detection circuit 71 for detecting lighting recovery at the time of an instantaneous power failure. This lighting detection circuit 71 is provided for the filament 13 after the momentary power failure.
The lighting power supplied to a is detected. The output of the lighting detection circuit 71 is supplied to a timer circuit 72. The timer circuit 72 starts a timer for measuring a preset predetermined time in response to a lighting return signal from the lighting detection circuit 71. The output of the timer 72 is supplied to the frequency control circuit 73. This frequency control circuit 73 controls the switching frequency of the FETs 9 and 10, which are the switching elements forming the inverter circuit.

Further, a voltage generating circuit 74 is connected to a connection point between one filament 13a of the discharge lamp 13 and the resonance capacitor 14, and an output of the voltage generating circuit 74 is supplied to the frequency control circuit 73. You. The voltage generation circuit 74 detects the lighting voltage of the filament 13a and performs control to shift to a lighting voltage lower than the rated lighting voltage after the discharge lamp 13 is started and after a certain period of rated lighting has elapsed.

The operation of returning from lighting at the moment of a momentary power failure will be described with reference to FIG. The lighting power for the discharge lamp 13 is generated by a switching operation of the FETs 9 and 10 of the inverter circuit to generate a high-frequency AC power and supplied to the discharge lamp 13. When starting the discharge lamp 13, the filament 13
Since it is necessary to perform pre-heating of a and 13b, FIG.
As shown in (1), a high frequency of the resonance frequency f0 having the maximum open voltage is output. The voltage supplied to the discharge lamp 13 at this time is 2.8 times the rated voltage b.

After a certain period of time has elapsed after the discharge lamp 13 has been started, the frequency is shifted to the lowest frequency a of the open-circuit voltage to reduce the power consumption.

When the lighting is maintained at this frequency a, the discharge lamp 13 can be turned off at the end of its life. However, since the open circuit voltage is low, the discharge lamp 13 having poor emission may be extinguished even if the discharge lamp 13 is not at the end of its life. This phenomenon occurs remarkably when lighting is restored after an instantaneous power failure.

At the time of rated lighting of the discharge lamp 13, as shown in FIG. 8 (b), an instantaneous power failure occurs between times t1 and t2. The lighting detection circuit 71 detects the re-lighting power supply to the discharge lamp 13 after the momentary power failure, and starts the timer of the timer 72 based on the detection of the re-lighting power. When the timer 72 is started, the frequency control circuit 73 controls the FETs 9 and 10 of the inverter circuit for preheating the discharge lamp 13. By this preheating operation, at time t3, the filaments 13a, 1
When 3b reaches a predetermined temperature, the frequency control circuit 73 controls the driving of the inverter circuit so as to supply the discharge lamp 13 with a starting voltage that is at least 1.8 times the rated lighting voltage b. By this starting operation, the filaments 13a, 13b
Starts discharging, and reaches rated lighting at time t4. At the time of rated lighting after time t4, the frequency control circuit 7
3 controls the FETs 9 and 10 of the inverter circuit to operate at the rated frequency b. When the rated lighting at the rated frequency b elapses for a certain period, the voltage generation circuit 7
By controlling the frequency control circuit 73 under the control of 4,
Control is performed so that the FETs 9 and 10 of the inverter circuit operate at a frequency a having a low open-circuit voltage.

Thus, at the time of lighting recovery after an instantaneous power failure,
It can be turned on again with low power and in a short time, and it can be turned on again by raising the open circuit voltage. After the passage, the lighting can be maintained at a lower driving voltage. This makes it possible to extend the life of the lighting device and save power.

[0098]

According to the discharge lamp lighting device of the present invention, when the filament of the thin tube discharge lamp is short-circuited by vibration, the short-circuit detection circuit detects the short-circuit of the filament, and the short-circuit detection detects the short-circuit of the filament. Since the drive of the inverter circuit that supplies lighting power to the filament can be stopped, a short-circuit of the filament of the discharge tube can be detected early,
In addition, it is possible to prevent the lighting circuit from being excessively operated due to the filament short circuit, and to prevent deterioration of the electronic component element.

The discharge lamp lighting device according to the second aspect of the present invention can easily detect the filament short-circuit of the discharge tube by the value of the filament voltage, and can stop driving of the inverter circuit that supplies the filament with lighting power. Excessive operation of the lighting circuit due to the filament short circuit can be prevented, and deterioration of the electronic component elements constituting the lighting circuit can be prevented.

The discharge lamp lighting device according to the third aspect of the present invention can easily detect the filament short-circuit of the discharge tube by the value of the filament current, and can stop the driving of the inverter circuit that supplies the filament with lighting power. Excessive operation of the lighting circuit due to the filament short circuit can be prevented, and deterioration of the electronic component elements constituting the lighting circuit can be prevented.

In the discharge lamp lighting device according to the fourth aspect of the present invention, when the filament of the discharge tube is short-circuited, a change in the filament voltage or current may not be distinguished due to the resistance of the lead wire or the like. In particular, when the temperature of the lead wire rises due to heat in the discharge tube, the resistance increases. Further, there is a case where the filament current does not change when the filament is short-circuited. In this case, by detecting the filament voltage / current, the detection accuracy of the filament short circuit is improved.

In the discharge lamp lighting device according to the fifth aspect of the present invention, the operation with the lighting device is stopped at the end of the life of the discharge tube, and unnecessary operation of the lighting device at the end of the discharge lamp can be prevented.

A lighting device for a discharge lamp according to a sixth aspect of the present invention is a lighting device for performing dimming control, wherein the reference power value of the comparing means is changed and set in accordance with the dimming control, thereby making it possible to control the dimming control. The accuracy of the filament short circuit determination is improved.

In the lighting apparatus according to the seventh aspect of the present invention, since the discharge lamp lighting device is incorporated in the lighting device, the lighting device can be prevented from being damaged when the filament of the discharge lamp mounted on the lighting device is short-circuited, and the lamp has a long life. Equipment can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an overall configuration of an embodiment of a discharge lamp lighting device according to the present invention.

FIG. 2 is a circuit diagram showing a discharge lamp filament short circuit detection circuit in the discharge lamp lighting device according to the present invention.

FIG. 3A is a block diagram of a window comparator according to another embodiment of the discharge lamp lighting device according to the present invention;
FIG. 3B is a voltage determination diagram illustrating a determination state of the window comparator.

FIG. 4 is a circuit diagram showing another embodiment of a discharge lamp filament short circuit detection circuit in the discharge lamp lighting device according to the present invention.

FIG. 5 is a characteristic diagram showing a relationship between a lamp current and a filament voltage of a discharge lamp when dimming control is performed using the discharge lamp lighting device according to the present invention.

FIG. 6 is a characteristic diagram illustrating the relationship between the output characteristics of the discharge lamp lighting device and the characteristics of the discharge lamp according to the present invention.

FIG. 7 is a circuit diagram showing an application example of the discharge lamp lighting device according to the present invention.

8A and 8B are explanatory diagrams illustrating an operation of an application example of the discharge lamp lighting measure according to the present invention. FIG. 8A is a characteristic diagram showing a relationship between a frequency and a filament voltage, and FIG. 8B is lighting after a momentary power failure. 4 is a time chart illustrating return.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Commercial AC power supply 2 ... Inductance 3 ... Capacitor 4 ... Rectifier circuit 5 ... Inductance 6 ... Switch element for chopper circuit 7 ... Diode 8 ... Electrolytic capacitor 9, 10 ... Switching element for inverter circuit 11 ... Capacitor 12 ... Current limiting inductance 13 ... discharge lamp 14 ... resonance capacitor 15 ... filament current detection winding 16 ... filament voltage detection circuit 17 ... filament current detection circuit 18 ... multiplication circuit 19 ... comparison circuit 20 ... control circuit

Continued on the front page F-term (reference)

Claims (7)

[Claims] 1. A rectifier for rectifying and smoothing a commercial AC power supply into a DC power supply; and an inverter means for converting the DC power supply generated by the rectifier into a high-frequency power supply and supplying the high-frequency power supply to a filament of a discharge lamp. A discharge lamp lighting device comprising: a short-circuit detecting means for detecting a filament short-circuit; and a control means for stopping and controlling the operation of the inverter means when the short-circuit detecting means detects a filament short-circuit. 2. A filament voltage detecting means for detecting a filament voltage of the discharge lamp,
Comparing means for comparing the filament voltage detected by the filament voltage detecting means with a predetermined reference value, and outputting a comparison result of the comparing means to the control means, wherein the control is performed when the filament voltage is equal to or less than a predetermined reference value. 2. The discharge lamp lighting device according to claim 1, wherein the operation of the inverter means is stopped by means. 3. A filament current detecting means for detecting a filament current of the discharge lamp,
Comparing means for comparing the filament current detected by the filament current detecting means with a predetermined reference value, outputting a comparison result of the comparing means to the control means, and controlling the control when the filament current is equal to or less than a predetermined reference value. 2. The discharge lamp lighting device according to claim 1, wherein the operation of the inverter means is stopped by means. 4. A filament voltage detecting means for detecting a filament voltage of the discharge lamp,
A filament current detecting means for detecting a filament current, a filament power based on the filament voltage and the current detected by the filament voltage and current detected by the detecting means, a power calculating means, and a filament power determined by the power calculating means. Comparing means for comparing with the reference value, and outputting the comparison result of the comparing means to the control means, and stopping the operation of the inverter means by the control means when the filament power is equal to or less than a predetermined reference value. The discharge lamp lighting device according to claim 1, wherein 5. The short-circuit detecting means includes a voltage and current detecting means for detecting a filament voltage value and a current value of the discharge lamp, and a filament voltage value and a current value detected by the voltage and current detecting means. The upper limit of the filament voltage value and the upper limit of the current value exceeds a predetermined value. 2. The discharge lamp lighting device according to claim 1, wherein the operation of the inverter means is stopped by driving control. 6. A reference value for comparing a filament voltage value and a current value of the discharge lamp by the comparing means of the short-circuit detecting means is:
The discharge lamp lighting device according to any one of claims 2 to 4, wherein the change is performed according to dimming control of the discharge lamp. 7. A discharge lamp lighting device according to claim 1, which controls lighting of the discharge lamp;
A lighting fixture comprising: