JP2002151288A - Discharge lamp lighting device and illumination device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device and an illumination device using above which aim at simplifying of a circuit structure and function by a digital calculation as well as make a reliable control possible. SOLUTION: A lighting circuit means OC containing a current-limiting impedance La and a discharge lamp DL for starting up and lighting by impressing high-frequency voltage generated by a high-frequency switching of switching means Q2 and Q3 on a discharge lamp DL, a filament heating means FHC to heat filament electrodes E1 and E2 of the discharge lamp DL, a switching current detecting means SCD to detect a current momentary value flowing at the switching means Q3, a control means CC which controls the switching means Q2, Q3 and decides an operating condition including preheating, starting-up and lighting conditions of the discharge lamp DL by the digital calculation, and detects errors of the discharge lamp DL observing a current detecting signal of the switching current detecting means SCD at a given phase of a switching period being synchronized with a drive signal of the switching means, are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge lamp lighting device for lighting a discharge lamp having a pair of filament electrodes at high frequency, and a lighting device using the same.

[0002]

2. Description of the Related Art When a discharge lamp having a pair of filament electrodes is turned on, the filament electrodes are first preheated as required when the power is turned on, and then started to prevent blackening of the discharge lamp due to sputtering of electrode materials. At the same time, in order to facilitate starting, it is conventionally performed.

It is dangerous if the power is turned on and a high starting voltage is applied to the lamp socket even though the discharge lamp is not mounted. Further, if the starting voltage is continuously output for a long time, a large stress acts on the circuit components, so that it must be avoided. Therefore, if a discharge lamp is not mounted for some reason by providing a lamp mounting detecting means, it is conventionally detected to detect this and protect the discharge lamp from being applied with a starting voltage.

Further, when the discharge lamp is started by a lighting circuit mainly composed of a high-frequency inverter, the discharge lamp is started, and when the discharge lamp is turned on, this is detected by lighting detection means, and the discharge lamp is stabilized under a required load condition. In some cases, the output voltage of the high-frequency inverter is controlled directly or indirectly by changing the oscillation frequency so as to light up.

Further, when the thermoelectron-emitting material attached to one of the pair of filament electrodes in the discharge lamp is exhausted and the end of its life is reached, the discharge lamp generates a half-wave discharge and a large discharge current in which a direct current is superimposed is generated. Flows. As a result, abnormal heat is generated in the vicinity of the filament electrode, and the synthetic resin base and lamp socket of the discharge lamp may be melted, leading to smoke and ignition. Therefore, protection has been conventionally performed by providing an end-of-life detecting means to detect the end of the life of the discharge lamp to stop the high-frequency generation operation, or to intermittently generate a high-frequency voltage.

Thus, in the prior art, the output signals of the above-described lamp mounting detection means, lighting detection means, and end-of-life detection means are input in parallel to the control means of the high-frequency generator, and the output signals correspond to the respective output signals. The control is always performed.

[0007]

However, in the prior art, since all the detection functions are always active, dedicated detection means are required, and the circuit structure of the control means responsive thereto is complicated. Therefore, there is a problem that the number of circuit components increases and reliable control tends to be difficult.

Further, since the detection output from the dedicated detection means is averaged, the abnormality of the discharge lamp cannot be detected by an instantaneous value. It is necessary to use a circuit component having a large margin that can be endured. Therefore, there is also a problem that constituent circuit parts are expensive.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a discharge lamp lighting device and a lighting device using the same, in which the circuit configuration and functions can be simplified by digital operation and the control can be reliably performed.

Another object of the present invention is to provide a discharge lamp lighting device and an illuminating device using the same, which can determine the abnormality of the discharge lamp such as the end of life and the absence of the discharge lamp by a simplified circuit configuration. For other purposes.

Further, the present invention provides a discharge lamp lighting device which can use circuit components with a relatively small margin as constituent circuit components of the lighting circuit means and is inexpensive accordingly, and a lighting device using the same. For other purposes.

[0012]

According to a first aspect of the present invention, there is provided a discharge lamp lighting apparatus for applying a high frequency voltage generated by high frequency switching of a switching means to a discharge lamp having a pair of filament electrodes via a current limiting impedance. Lighting circuit means for starting and lighting the discharge lamp;
A filament heating means for heating a filament electrode of the discharge lamp at least at the time of preheating of the discharge lamp; a switching current detecting means for detecting an instantaneous value of a current flowing through the switching means of the lighting circuit means; The operation state including each state of preheating, starting and lighting of the discharge lamp is determined by digital operation, and the current detection signal of the switching current detection means is synchronized with a drive signal of the switching means of the lighting circuit means at a predetermined phase of a switching cycle. And control means for judging abnormality in the discharge lamp by monitoring the discharge lamp.

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

<Regarding lighting circuit means> The lighting circuit means applies a high-frequency voltage generated by high-frequency switching of the switching means provided thereto to a discharge lamp having a pair of filament electrodes via a current-limiting impedance. If you start the discharge lamp and turn it on,
Other configurations are not limited. However, in general, it is constituted by high-frequency generation means provided with switching means, and a load circuit including a discharge lamp provided with a current limiting impedance and a pair of filament electrodes in series.

The high-frequency generating means provided with the switching means may have any configuration as long as the switching means performs high-frequency switching to generate a high-frequency voltage and obtain electric power necessary for lighting the discharge lamp. It may be. For example, a half-bridge type inverter, a full-bridge type inverter, a parallel type inverter, a single-type inverter and the like can be used alone or in combination with a switching regulator as an active filter. Further, by using the switching means of the inverter as the switching means of the active filter, a so-called composite inverter having an active filter can be used.
The switching means can be driven via a gate drive circuit without directly driving the switching means by a drive signal sent from the control means described later. In this case, the high frequency generation means can be provided with a gate drive circuit.

In the present invention, “high frequency” means
Refers to a frequency of 10 kHz or more.

The high-frequency generating means is configured to be controlled by control means to be described later and to vary the high-frequency output as required. A variable high-frequency output can be realized, for example, by changing the oscillation frequency, changing the duty ratio of high-frequency switching to change the output voltage, or changing the output voltage of the active filter.

Next, the load circuit will be described.

The load circuit is formed by connecting the current limiting impedance and the discharge lamp in series as described above.
The current limiting impedance is used for compensating for the negative characteristics of the discharge lamp and for stably lighting the discharge lamp by passing a constant lamp current through the discharge lamp. Although any of inductive reactance, capacitive reactance, and resistance may be used, it is common to use the former which theoretically does not generate power consumption. Also, to make the lamp current waveform good,
Preferably, an inductive reactance is used. However, even if they show inductive or capacitive reactance as a whole,
A composite circuit including a capacitive reactance or an inductive reactance as a reactance component can be adopted as the current limiting impedance. Further, when an inductive reactance is used as the current limiting impedance, any of a single choke coil and a leakage transformer may be used.

The discharge lamp may be any discharge lamp provided that it has a pair of filament electrodes.
For example, it may be a fluorescent lamp, a germicidal lamp, or the like. The discharge lamp can be lit by connecting not only one lamp but also a plurality of lamps in series or in parallel as desired.

<Regarding Filament Heating Means> In the filament heating means, the non-power supply side terminals of the pair of filament electrodes are connected by impedance, and the power supply side terminals of the pair of filament electrodes are connected between the output terminals of the high frequency generation means. A configuration can be employed. in this case,
The impedance has an appropriate impedance value to pass a required value of the filament heating current. If a load circuit mainly forms a series resonance circuit with the current limiting impedance of the load circuit, a high starting voltage due to series resonance is generated in the filament heating circuit at the time of starting, and this starting voltage is applied to the discharge lamp. Thereby, the starting of the discharge lamp can be promoted. When the current limiting impedance is composed of inductive reactance, it is preferable to use a capacitor having capacitive reactance in the filament heating circuit. Conversely, when the current limiting impedance is a capacitive reactance, an inductive reactance may be used in the filament heating circuit. In addition,
If desired, a resistor can be used in the filament heating circuit.

Further, the filament heating circuit may be constituted by connecting the secondary winding of the filament heating transformer in parallel or in series with the filament.

<Regarding the Switching Current Detecting Means> The switching current detecting means is means for detecting the instantaneous value of the current flowing through the switching means for performing high frequency switching of the lighting circuit means. The detection of the current flowing through the switching means is performed at a predetermined phase in synchronization with the switching cycle, as described later. However, any specific configuration can be used as long as the instantaneous value at that time can be reliably determined. You may. For example, a resistor having a relatively small value is inserted in series with the switching means and current is detected based on the voltage drop. A primary winding of the current transformer is inserted in series with the switching means and a secondary winding is inserted. The current can be detected by the voltage appearing on the line.

<Control Means> The control means determines the operating state of the discharge lamp by digital operation by controlling the switching of the switching means of the lighting circuit means, for example, by controlling the switching cycle (oscillation frequency) or duty ratio. In determining the operation state, the operation state is determined based on a program which is set and stored in advance, and further, as necessary, based on a detection result of required detection means, for example, a switching current detection means. The “operation state of the discharge lamp” refers to each state of operation including at least each state of preheating and starting performed prior to lighting of the discharge lamp and lighting. This term refers to a condition that should be operated rather than that the discharge lamp is actually operating in such a condition. In order to determine the operation state of the discharge lamp by digital operation, a digital operation processing device, for example, a programmable element such as a microcomputer can be used. The program is stored in the main storage device of the digital processing device, and acts to control the operation.

Further, the control means determines whether the discharge lamp is abnormal. The “discharge lamp abnormality” refers to the end of life and / or the absence of the discharge lamp. When the discharge lamp is not mounted, the discharge lamp itself is not abnormal, but when viewed from the lighting circuit means side, since there is no load, a normal lighting operation cannot be performed. Is to judge this as a kind of abnormality. In order to determine the abnormality of the discharge lamp, it is necessary to monitor the operation state of the discharge lamp. In the present invention,
The configuration is characterized in that the abnormality of the discharge lamp is determined by monitoring the output signal of the switching current detection means in the control means. That is, the output signal of the switching current detecting means is monitored at a predetermined phase of the switching cycle in synchronization with the drive signal of the switching means of the lighting circuit means, and an abnormality is determined by comparing the output signal with table data input in advance.

<Other Configurations> Although not an essential component of the present invention, one or more items can be selectively added to the following configurations as desired.

1. Protective operation shifting means When an abnormality such as the end of the life of the discharge lamp is determined, the protective operation can be shifted to the protective operation. In addition,
The “protection operation” refers to an operation for ensuring safety, for example, by not applying a high-frequency voltage to the lighting circuit means, applying the high-frequency voltage indirectly, or applying a reduced high-frequency output. In order to perform the protection operation, for example, the control means may control the switching means as required.

2. About Abnormality Display Means When it is determined that an abnormality has occurred in the discharge lamp, it can be configured to display that fact. This display is light,
This can be performed using a medium such as sound, color, or text.

<Operation of the present invention> Since the control means controls the lighting circuit means in sequence by digital operation before the discharge lamp is turned on, the lighting circuit means applies a high frequency voltage supplied to the discharge lamp to the discharge lamp. In the discharge lamp, the filament electrode is first preheated (during preheating), then started (at startup), and finally turned on (during lighting). That is, the control means determines the operating state of the discharge lamp via the lighting circuit means by digital operation. Since a high-frequency output voltage corresponding to each process is applied from the lighting circuit means via the current-limiting impedance to the discharge lamp, the discharge lamp eventually stably lights.

If the discharge lamp reaches the end of its life during lighting or if the discharge lamp is not mounted for some reason, the current flowing through the switching means of the lighting circuit means changes. Then, the switching current detecting means detects the instantaneous value of the current flowing through the switching means and sends it to the control means. The control means monitors the instantaneous value of a predetermined phase synchronized with the switching cycle of the switching means, which is sent from the switching current detection means, and determines whether there is an abnormality in the discharge lamp by comparing the instantaneous value with a built-in table data. I do.

When the control means determines that an abnormality has occurred in the discharge lamp, the control means shifts to a protection operation (during protection operation),
It performs display and performs a desired operation according to the configuration.

Hereinafter, the operation will be described in detail focusing on the detection and the correspondence at each process.

(Operation at the time of preheating) At the time of preheating, the filament electrode is energized and heated to make a sufficient thermoelectron emission state. However, an undesired start is not performed before the thermoelectron emission state becomes sufficient. In addition, it is desirable to reduce the high frequency output. Also, at the time of preheating, it is possible to detect that the discharge lamp is mounted as required based on a current detection signal from the switching current detection means. Then, when the lamp installation is detected, the filament electrode is preheated in a predetermined manner, and after the preheating, the operation shifts to the starting time.

(Starting Operation) At the time of starting, the high-frequency output voltage is increased in order to easily and reliably support the starting of the discharge lamp. To increase the high frequency output voltage,
For example, a resonance circuit including a current-limiting impedance of the lighting circuit means and an impedance connected in parallel to the discharge lamp is configured, and a high-frequency oscillation frequency generated by high-frequency switching of the switching means of the lighting circuit means is adjusted. It can be easily realized by approaching the resonance frequency of the resonance circuit. It can also be realized by directly increasing the high-frequency output voltage.

Further, at the time of starting, it is possible to easily detect that the discharge lamp is turned on based on the instantaneous value of a predetermined phase of the current detection signal from the switching current detection means. Then, when the lighting is detected, the high-frequency output generated by the high-frequency switching of the switching means is in a state suitable for maintaining the intended lighting state of the discharge lamp, that is, a predetermined lamp current flows stably. Control.

(Operation at Lighting) At the time of lighting, the end of the life of the discharge lamp can be detected based on the current detection signal from the switching current detecting means as described above.

According to a second aspect of the present invention, there is provided a discharge lamp lighting device,
2. The discharge lamp lighting device according to claim 1, wherein the control means stores a program for determining a state of the lighting circuit means and generates a drive signal, a temporary storage memory for temporarily storing data, and A central processing unit for performing an arithmetic operation according to a program stored in the read-only memory is provided.

The present invention specifies a preferred configuration of the control means.

That is, the read-only memory is a so-called R
OM, which stores a program for determining a desired operating state of the lighting circuit means at each time and generating a drive signal of the switching means corresponding to the determined state.

The temporary storage memory is a so-called RAM, and temporarily stores output data and input data calculated by the central processing unit. The input data once stored in the temporary storage memory is sent to the central processing unit at a predetermined timing and is operated. The output data is output as a drive signal via a D / A converter or the like at a predetermined timing and as abnormality detection data.

The central processing unit is a so-called CPU,
A required operation is performed based on a program set in advance and stored in the read-only memory, and the result is sent to a temporary storage memory to be temporarily stored.

According to a third aspect of the present invention, there is provided a discharge lamp lighting device,
The discharge lamp lighting device according to claim 1 or 2,
The switching current detection means detects a current flowing through the switching means of the lighting circuit means to generate a current detection signal, a sample and hold circuit for sampling and holding the current detection signal, and a digital signal for sampling and holding the current detection signal. And an A / D converter for converting the current detection signal to a control means.

The present invention defines a preferred configuration of the switching current detecting means.

That is, the current detector can be constituted by a resistor, a current transformer and the like inserted in series with the switching means, and obtains a voltage corresponding to the instantaneous value of the current.

The sample and hold circuit is a circuit for holding an instantaneous value of a predetermined phase of a current detection signal of the switching current detector.

The A / D converter is a circuit for converting the output of the sample and hold circuit from an analog signal to a digital signal.

According to a fourth aspect of the present invention, there is provided a lighting device comprising: a lighting device main body; and the discharge lamp lighting device according to any one of the first to third aspects supported by the lighting device main body. And

In the present invention, the term “illumination device” has a broad concept including any device that uses light emitted from a discharge lamp for some purpose. For example, it includes a lighting fixture, a display device, an image reading device, and the like.

The "illumination device main body" means the remaining portion obtained by removing the discharge lamp lighting device from the illumination device.

[0050]

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

FIG. 1 is a circuit block diagram for explaining the basic concept of the discharge lamp lighting device of the present invention.

In the figure, AS is a low-frequency AC power supply, OC
Is lighting circuit means, FHC is filament heating means, FC
D is a filament current detecting means, and CC is a control means.

The low-frequency AC power supply AS comprises a commercial AC power supply.

The lighting circuit means OC includes high-frequency generation means HF
G and a load circuit LC. High frequency generator HFG
Is a means for generating high frequency, the input terminal of which is connected to the low frequency AC power supply AS, and the output terminal of which is connected to the load circuit LC. The high-frequency generating means HFG includes a switching means Q therein, and the switching means Q
Generates high frequency by performing high frequency switching. The load circuit LC includes a series circuit of a DC cut capacitor C1, a current limiting impedance L1, and a discharge lamp DL. The discharge lamp DL includes a pair of filament electrodes E1 and E2 sealed at both ends of the discharge vessel.

The filament heating means FHC is of a so-called capacitor heating circuit type. By connecting a capacitor C2 between the non-power supply side terminals of the pair of filament electrodes E1 and E2 of the discharge lamp DL, one filament of the discharge lamp DL is connected. A series circuit of the electrode E1, the capacitor C2 and the other filament electrode E2 is formed. Then, the filament heating means FHC is supplied via the load circuit LC.
When the high-frequency current flows through the capacitor C2, the filament electrodes E1 and E2 are heated.

The switching current detecting means SCD is means for detecting the instantaneous value of the current flowing through the switching means Q of the lighting circuit means OC, and comprises a current detector CD and an instantaneous value detecting circuit IVD. The current detector CD is composed of a resistor having a small resistance connected in series with the switching means Q, and an instantaneous value of the switching current is obtained by a voltage drop of the resistor. The instantaneous value detection circuit IVD can be constituted by a sample and hold circuit and an A / D converter. The sample hold circuit holds an instantaneous value of a predetermined phase of a voltage drop generated in the current detector CD. Further, the A / D converter A / D converts the output of the sample hold circuit and sends it to the control means CC.

The control means CC is composed of a digital processing unit, and determines the operating state including the preheating, starting and lighting states of the discharge lamp DL by digital calculation, and judges abnormality of the discharge lamp DL. The abnormality of the discharge lamp DL is determined by the control means C based on the digitized instantaneous current detection signal of a predetermined phase of the switching current sent from the switching current detection means SCD.
It is obtained by calculation in C.

FIG. 2 is a circuit diagram showing a first embodiment of the discharge lamp lighting device of the present invention.

In the figure, the same parts as those in FIG. In the present embodiment, the high frequency generation means HFG of the lighting circuit means OC is a noise filter N.
F, a rectified DC power supply RDC, an active filter AF, and a high-frequency inverter HFI, and the control means CC has a configuration described later.

That is, the noise filter NF in the high-frequency generation means HFG of the lighting circuit means OC is inserted between the low-frequency AC power supply AS and the rectified DC power supply RDC, and is used for switching of switching means Q1, Q2, Q3 described later. The high frequency noise generated by the
Cut so that it does not flow out to the S side.

The rectified DC power supply RDC is constituted by a full-wave rectifier circuit, and is interposed between the noise filter NF and the active filter AF to rectify a low-frequency AC voltage to form a non-smooth DC voltage.

The active filter AF is composed of a step-up chopper, and intervenes between the rectified DC power supply RDC and the high-frequency inverter HFI to convert the smoothed and required boosted DC voltage at a high power factor and at a low level. Output under harmonic distortion. That is, the boost chopper is connected to the inductor L
2. The switching means Q1, the diode D1, the smoothing capacitor C3, and the gate drive circuit GDC1 are configured as elements. The inductor L2 and the switching means Q1 are connected in series and connected between the DC output terminals of the rectified DC power supply RDC. The diode D1 and the smoothing capacitor C3 form a series circuit, and are connected between both ends of the switching means Q1. The gate drive circuit GDC1 drives and switches the gate of the switching means Q1. Thus, a smoothed DC voltage boosted across the smoothing capacitor C3 is obtained.

The high-frequency inverter HFI is a half-bridge type inverter and includes first and second switching means Q2 and Q3, and a gate drive circuit GDC2. Then, it operates using the smoothed DC voltage of the active filter AF as a power supply, and outputs a high-frequency voltage to its output terminal. First and second switching means Q2, Q2
3 is connected in series to the smoothed DC voltage, and performs high-frequency switching alternately, so that the load circuit L
A high frequency voltage is applied to C.

The control means CC includes a memory M, an input / output interface I / O, a central processing unit CPU, and a bus line BL. The memory M, the input / output interface I / O, and the central processing unit CPU are configured to mutually transmit and receive data via the bus line BL. The memory M includes a read-only memory ROM and a temporary storage memory RAM. Read-only memory R
The OM stores a program. The input / output interface I / O is a gate drive circuit GDC1, GDC
2 sends a drive signal. The central processing unit CPU
The calculation is performed based on the program stored in the memory M and the input data from the switching current detection means SCD, the result is temporarily stored in the memory M, and the output data is transmitted to the input / output interface I / O at a predetermined timing. And generate a drive signal.

FIG. 3 is a waveform diagram showing current and voltage waveforms at various parts in the first embodiment of the discharge lamp lighting device of the present invention.

In the figure, (a) shows the switching means Q
3, (b) is a current detection signal voltage, (c)
Indicates the drive signal voltage, and (d) indicates the current detection voltage at the end of the life of the discharge lamp.

That is, if the discharge lamp DL is normal, the drain current of the switching means Q3 has a waveform as shown in FIG.
As shown in FIG. 7, the waveform is proportional to the drain current. However, when the discharge lamp reaches the end of its life, the switching means Q3 performs the fast-phase switching, so that the waveform becomes as shown in FIG. Therefore, the instantaneous value of the switching current, that is, the drain current is determined by setting the phase at the moment when the switching means Q3 is turned off as the detection phase.
Since there is a clear difference depending on the operating state of L, the abnormality of the discharge lamp can be reliably determined.

FIG. 4 is a circuit diagram showing a second embodiment of the discharge lamp lighting device according to the present invention.

In the figure, the same parts as those in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted. In the present embodiment, the switching current detecting means SCD 'is different.

That is, the switching current detecting means SC
D 'is configured such that the current detector CD' is formed of a current transformer, the primary winding of which is connected in series to the switching means Q3, and the resistor R2 is connected in parallel with the secondary winding. Thus, a current detection signal is obtained across the resistor R2.

FIG. 5 is a perspective view showing a trough-type lighting device as one embodiment of the lighting device of the present invention.

FIG. 16 is a partially cutaway front view showing the fluorescent lamp.

In each of the figures, reference numeral 1 denotes a trough type lighting fixture main body, and 2 denotes a fluorescent lamp.

The trough-shaped luminaire main body 1 has an inverted trapezoidal cross section and is elongated, and houses the discharge lamp lighting device shown in FIG. 1 except for the fluorescent lamp.

A lamp socket 1a is disposed at one longitudinal end of the lower surface of the trough-shaped lighting device main body 1 so as to be exposed downward from the lower surface.

Further, a lamp holder 1b is provided near the other end of the trough-shaped lighting fixture body 1 in the longitudinal direction.

The fluorescent lamp 2 includes a U-shaped translucent discharge vessel 2a, a base 2b, and a spacer 2c.

The translucent discharge vessel 2a is composed of two glass tubes 2
a1 and 2a1 are made parallel to each other, and a connecting portion 2a2 is formed at the tip to form one U-shaped discharge path, and a pair of filament electrodes (not shown) are sealed at both ends. A phosphor layer of a three-wavelength emission type is formed on the inner surface of the translucent discharge vessel 2a, and an appropriate amount of mercury and argon are sealed therein at 200 to 300 Pa.

The base 2b is a GY10q-12 type, and is mounted at one end of the light-transmissive discharge vessel 2a at both ends where the discharge path is folded.

Thus, the fluorescent lamp 2 has a tube diameter of 17.5.
mm, a tube length of 1150 mm, and a rated lamp power of 105 W. The base 2b is attached to the lamp socket 1a of the trough-shaped lighting fixture main body 1, and the front end side of the translucent discharge vessel 1 is supported by the lamp holder 1b to form a trough. It is attached to the lighting fixture body 1.

[0081]

According to the first to third aspects of the present invention, a discharge lamp having a current limiting impedance and a pair of filament electrodes is applied, and a high-frequency voltage generated by high-frequency switching of switching means is applied to the discharge lamp for starting. Lighting circuit means for heating and lighting, a filament heating means for heating a filament electrode of the discharge lamp, a switching current detecting means for detecting an instantaneous value of a current flowing through a switching means of the lighting circuit means, and a switching means for the lighting circuit means. The operation state including the preheating, starting and lighting states of the discharge lamp is determined by digital operation, and the current detection signal of the switching current detection means is monitored at a predetermined phase of the synchronous switching cycle in synchronization with the drive signal of the switching means. Control means for detecting abnormalities of In this way, the circuit configuration can be simplified, reliable control can be performed, abnormality of the discharge lamp can be determined, and if necessary, the lighting circuit means can be composed of circuit components with a relatively small margin. A lamp lighting device can be provided.

According to the second aspect of the present invention, in addition to the above, the control means includes a read-only memory, a temporary storage memory, and a central processing unit, thereby providing a discharge lamp lighting device including a control means having a preferable configuration. can do.

According to the third aspect of the present invention, since the switching current detecting means further includes a current detector, a sample-and-hold circuit and an A / D converter, the discharge having the switching current detecting means of a suitable configuration is provided. A lamp lighting device can be provided.

According to the fourth aspect of the present invention, it is possible to provide a lighting apparatus having the effects of the first to third aspects by including the lighting apparatus main body and the discharge lamp lighting apparatus of the first to third aspects. it can.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram illustrating a basic concept of a discharge lamp lighting device according to the present invention.

FIG. 2 is a circuit diagram showing a first embodiment of the discharge lamp lighting device of the present invention.

FIG. 3 is a waveform chart showing current and voltage waveforms of respective parts in the first embodiment of the discharge lamp lighting device of the present invention.

FIG. 4 is a circuit diagram showing a second embodiment of the discharge lamp lighting device of the present invention.

FIG. 5 is a perspective view showing a trough-type lighting device as one embodiment of the lighting device of the present invention.

FIG. 6 is a partially cutaway front view showing the same fluorescent lamp.

[Explanation of symbols]

 ADC A / D converter AF Active filter AS AC power supply BL Bus line C1 DC cut capacitor C2 Capacitor C3 Smoothing capacitor CC Control means CD Current detector CPU Central processing unit D1 Diode DL Discharge Lamp E1 Filament electrode E2 Filament electrode FHC Filament heating circuit GDC1 Gate drive circuit GDC2 Gate drive circuit HFG High frequency generator HFI High frequency inverter I / O Input / output interface IVD Instantaneous value detection circuit L1 Current limiting Impedance L2 Inductor LC Load circuit M Memory NF Noise filter OC Lighting circuit means Q1 Switching means Q2 First switching means Q3 Second switching means RDC Rectified DC Sources SCD ... switching current detecting means SHD ... sample and hold circuit

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 3K072 AA02 AB02 AB03 BA05 BC01 BC02 DB03 DD04 DE02 EA01 EA02 EA08 EB06 EB08 EB10 FA05 GB04 GB12 GB18 GC04 HA06 HA10

Claims (4)

[Claims] A lighting circuit means for applying a high-frequency voltage generated by high-frequency switching of a switching means to a discharge lamp having a pair of filament electrodes via a current-limiting impedance to start and turn on the discharge lamp; Filament heating means for heating the filament electrode of the discharge lamp at least during preheating of the lamp; switching current detection means for detecting the instantaneous value of the current flowing through the switching means of the lighting circuit means; The operation state including each state of preheating, starting and lighting of the lamp is determined by digital operation, and the current detection signal of the switching current detection means is synchronized with a drive signal of the switching means of the lighting circuit means at a predetermined phase of the switching cycle. Monitor to determine discharge lamp abnormalities Discharge lamp lighting apparatus, characterized in that it comprises a; and control means. 2. The control means is stored in a read-only memory storing a program for determining a state of the lighting circuit means and generating a drive signal, a temporary storage memory for temporarily storing data, and a read-only memory. 2. The discharge lamp lighting device according to claim 1, further comprising a central processing unit for performing an arithmetic operation according to the program. 3. The switching current detecting means detects a current flowing through the switching means of the lighting circuit means to generate a current detection signal, a sample and hold circuit which samples and holds the current detection signal, and a sampled and held current. A / A that converts the detection signal into a digital signal
3. The discharge lamp lighting device according to claim 1, further comprising a D converter, and transmitting a digitized current detection signal to the control unit. 4. A lighting device comprising: a lighting device main body; and the discharge lamp lighting device according to claim 1 supported by the lighting device main body.