JP5712359B2 - Discharge lamp lighting device and lighting fixture equipped with discharge lamp lighting device - Google Patents

Description

  The present invention relates to a discharge lamp lighting device for dimming and lighting a discharge lamp, and a lighting fixture including the discharge lamp lighting device.

  Conventionally, when a fluorescent lamp such as a discharge lamp is lit, a preheating mode is set in which a current sufficient to discharge thermal electrons from the filament is set before applying a starting voltage to both ends of the fluorescent lamp. 2. Description of the Related Art A discharge lamp lighting device that suppresses stress at the time of lamp flashing and prevents a fluorescent lamp from having a short life and a lighting fixture including the discharge lamp lighting device are known (for example, see Patent Document 1).

Japanese Patent No. 3728934 (FIG. 1, claim 1)

  In the lighting apparatus including the discharge lamp lighting device and the discharge lamp lighting device described in Patent Document 1 described above, a start mode in which a start voltage is applied to both ends of the fluorescent lamp for a certain period after the preheating mode and the fluorescent lamp is started and lit is provided. Is set. After the start mode, the fluorescent lamp is set to a lighting mode that is a normal lighting state.

  Moreover, the lighting fixture provided with the discharge lamp lighting device and the discharge lamp lighting device described in Patent Document 1 described above changes the inverter operating frequency in each mode of the preheating mode, the start mode, and the lighting mode, and changes to each mode. A suitable inverter output (corresponding to the lamp output. However, the fluorescent lamp is lit during the start mode and the lamp output is lit during the start mode according to the inverter frequency in the start mode).

  And the lighting fixture provided with the discharge lamp lighting device described in patent document 1 mentioned above and a discharge lamp lighting device is based on the 1st frequency determination circuit which determines the frequency in a preheating mode and a starting mode, and a light control signal. A second frequency determining circuit for determining a frequency. The inverter frequency is determined by a composite value of the first setting signal and the second setting signal, and the setting signal of the second frequency setting circuit is set so as to be equal to or lower than the maximum switching frequency in the lighting mode when switching from the start mode to the lighting mode. Change gradually.

  Thereby, the lighting fixture provided with the discharge lamp lighting device and the discharge lamp lighting device described in Patent Document 1 described above has a dimming lower limit that is so-called dimming start at the time of transition from the start mode to the lighting mode. However, it is possible to prevent the lamp current from being too low and extinguishing due to excessive dimming beyond the original dimming lower limit level.

However, the discharge lamp lighting device and the lighting fixture provided with the discharge lamp lighting device described in Patent Document 1 described above transiently have a lamp output higher than the Full output when switching from the start mode to the lighting mode. .
This is because the oscillation circuit operates from a frequency (fmin) lower than the inverter operating frequency at the time of Full output when the lighting mode is switched.

  As shown in FIG. 7, in the discharge lamp lighting device 100 in the lighting fixture including the discharge lamp lighting device and the discharge lamp lighting device described in Patent Document 1 described above, the switch SW3 is turned off when switching from the start mode to the lighting mode. Therefore, the frequency starts from a value determined only by the current I1 (resistor R1). In addition, since the current I4 (resistor R4) gradually increases, the frequency becomes lower than the frequency during the desired full lighting for a certain period.

As shown in FIGS. 8A to 8H, the discharge lamp lighting device 100 in the lighting apparatus including the discharge lamp lighting device and the discharge lamp lighting device described in Patent Document 1 described above is turned on even at point A10. At the time of mode switching, the frequency becomes lower than the frequency lower than that at the time of Full.
As a result, as shown in FIG. 9, the discharge lamp lighting device 100 in the lighting apparatus including the discharge lamp lighting device and the discharge lamp lighting device described in Patent Document 1 described above has a lamp current that is transiently higher than the Full output. It will increase.

Moreover, since the discharge lamp lighting device 100 in the lighting fixture provided with the discharge lamp lighting device and the discharge lamp lighting device described in Patent Document 1 described above has a lower inverter frequency in the full lighting than an inverter frequency in the start mode. In addition, dimming is performed after increasing the lamp output that is lit during the start mode period.
This gives an uncomfortable feeling to the human eye as a flash when starting.

  In addition, the discharge lamp lighting device and the lighting fixture including the discharge lamp lighting device described in Patent Document 1 described above may be extinguished at the time of start-up due to a change in usage environment, component variations, or fluorescent lamp variations. is there.

That is, in the conventional discharge lamp lighting device 100 shown in FIG. 7, when the values of the capacitor C1 and the resistors R1 and R4 that determine the frequency in the lighting mode vary due to tolerances and temperature characteristics, particularly when the capacitor C1 varies, the dimming signal Even if Vd is the same value, the frequency will be higher than the original value, so that extinction occurs.
This is because the capacitance of the capacitor C1 decreases due to variations in capacitance tolerance and the ambient temperature, and the values of the resistors R1 and R4 are low, and when the currents I1 and I4 are large, the frequency becomes higher than the desired inverter frequency. .

Moreover, the discharge lamp lighting device 100 in the lighting fixture provided with the discharge lamp lighting device and the discharge lamp lighting device described in Patent Document 1 described above is also near the inverter frequency at the dimming lower limit at point B10 shown in FIG. The operating frequency has increased transiently.
Therefore, if the discharge lamp lighting device and the discharge lamp lighting device 100 in the lighting fixture including the discharge lamp lighting device described in Patent Document 1 described above are designed in consideration of this variation, the dimming lower limit level must be set high. I must. That is, deep dimming is not possible.

As described above, the discharge lamp lighting device 100 and the lighting fixture including the discharge lamp lighting device 100 described in Patent Document 1 described above have a lamp output (starting mode) higher than a desired Full output at the time of transition from the starting mode to the lighting mode. This corresponds to the above lamp output), and at the time of dimming start, there is a possibility that the lamp output will be below the desired dimming lower limit.
Even if no extinction occurs, if the lamp output is more than Full or less than the dimming lower limit, it will cause stress on the lamp filament, and the lamp will start to feel strange as a flashlight. Become.

  SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems. The object of the present invention is to transiently prevent the lamp output from being more than the Full output at the time of dimming lamp start, and to transiently at the time of dimming start. Dimming without exceeding the light output in the start mode, and preventing the lamp output from falling below the desired dimming lower limit prevents the lamp from extinguishing, giving the lamp filament stress and discomfort to the human eye. Disclosed is a discharge lamp lighting device and a lighting fixture including the discharge lamp lighting device.

A discharge lamp lighting device according to the present invention controls a DC power source, an inverter circuit that converts a DC voltage of the DC power source into a high frequency voltage by switching with a switching element, and supplies the high frequency voltage to the discharge lamp, and controls an output of the inverter circuit and a control circuit for the said control circuit detects the inverter current flowing through the discharge lamp current or the inverter circuit of the discharge lamp, and a detection circuit for outputting a detection signal, the discharge lamp current or the inverter current An error amplification circuit that amplifies an error between a target value for obtaining a desired value and a detection value of the detection signal , and a filament electrode included in the discharge lamp is preheated for a predetermined time before the discharge lamp is started and lit. Preheating mode, applying a starting voltage for starting and lighting the discharge lamp for a predetermined time after preheating the filament electrode of the discharge lamp And a timer circuit that controls switching to a lighting mode in which the discharge lamp is steadily turned on after the discharge lamp is turned on, and a frequency setting signal is changed according to the timer circuit, and the preheating mode, the start mode, comprising an oscillation circuit for determining the switching frequency of the inverter circuit in the lighting mode, the switching frequency of the inverter circuit in the lighting mode, a first lighting mode frequency determined only by the oscillation circuit, the oscillation circuit wherein a second lighting mode frequency determined by both the output signal of the error amplifier circuit, the a, the preheat mode, in the starting mode, the output signal of said error amplification circuit, the switching frequency of the inverter circuit The value is fixed so as not to affect the lighting, and the start mode is switched to the lighting mode. When switching, only increased the frequency of switching frequency in the starting mode of the inverter circuit to the second lighting mode frequencies, or so that only reduced, the frequency setting signal of the oscillation circuit and of said error amplifier circuit When changing the output signal and switching from the start mode to the lighting mode, a certain delay time is provided until the switching frequency of the inverter circuit changes, and the output of the error amplifier circuit immediately after switching to the lighting mode signal gradually changes, if the delay time has elapsed, based on the output signal of said error amplification circuit, the detection value of the detection device signals is fed back control performed so as to come close to the target value.

The discharge lamp lighting device according to the present invention, when switching from the starting mode of the lighting Modohe, Ru gradually changed frequency setting signal of the oscillation circuit.

The discharge lamp lighting device according to the present invention, after the switching from the starting mode of the lighting Modohe, the output signal of said error amplification circuit, a period of time, not drop below a defined value.

Lighting device according to the present invention includes the any one of the discharge lamp lighting device, a discharge lamp lighting operation is controlled by the discharge lamp lighting device.

  According to the discharge lamp lighting device and the lighting fixture including the discharge lamp lighting device according to the present invention, the lamp output is not transiently higher than the Full output when the dimming lamp is started, and is transiently used for the dimming start. Dimming without exceeding the light output in the start mode, and the lamp output does not become less than the desired dimming lower limit, it can prevent the lamp from extinguishing, it does not give stress to the lamp filament and uncomfortable to human eyes There is an effect.

The circuit diagram of the lighting fixture provided with the discharge lamp lighting device of 1st Embodiment which concerns on this invention, and a discharge lamp lighting device Detailed circuit diagram of the main part of the discharge lamp lighting device of FIG. FIG. 1 is a relationship diagram of the lamp radio wave waveform, inverter frequency and terminal voltage in the discharge lamp lighting device of FIG. The discharge lamp lighting device of 2nd Embodiment which concerns on this invention, and the relationship figure of the lamp current waveform, inverter frequency, and terminal voltage of a discharge lamp lighting device in a lighting fixture provided with a discharge lamp lighting device The detailed circuit diagram of the principal part of the discharge lamp lighting device in a lighting fixture provided with the discharge lamp lighting device and discharge lamp lighting device of 3rd Embodiment which concerns on this invention Lamp current waveform diagram in the discharge lamp lighting device of FIG. Circuit diagram of a conventional discharge lamp lighting device and a discharge lamp lighting device in a lighting fixture including the discharge lamp lighting device (A)-(h) Waveform diagram explaining operation | movement of a lighting fixture provided with the conventional discharge lamp lighting device and a discharge lamp lighting device. Conventional discharge lamp lighting device and lamp current waveform diagram of lighting fixture provided with discharge lamp lighting device

DESCRIPTION OF EMBODIMENTS Hereinafter, a discharge lamp lighting device according to a plurality of embodiments and a lighting fixture including the discharge lamp lighting device according to the present invention will be described with reference to the drawings.
(First embodiment)
As shown in FIG. 1, in a lighting fixture including the discharge lamp lighting device and the discharge lamp lighting device according to the first embodiment of the present invention, the lighting fixture 1 includes a discharge lamp lighting device 10 and a discharge lamp LA.
The discharge lamp lighting device 10 includes a rectifier DB that performs full-wave rectification of the AC voltage of the AC power supply Vs, and a DC power supply unit 12 that includes a smoothing capacitor (not shown) and a power supply circuit 11 that smoothes the pulsating voltage of the rectifier DB. An inverter circuit 13 that switches a DC voltage of the DC power source 12 to a high-frequency voltage by switching with a switching element (not shown), a resonance circuit 14 that includes an inductor and a capacitor connected to an output terminal of the inverter circuit 13, and a resonance The control circuit 15 is configured to control the output of the inverter circuit 13 connected to the circuit 14, and is connected to the discharge lamp LA.

  The control circuit 15 includes an oscillation circuit 16 that controls the switching frequency of the switching element of the inverter circuit 13, a drive circuit 17 that turns on and off the switching element based on the output of the oscillation circuit 16, and a discharge lamp LA before the discharge lamp LA is started. For setting each time of a preheating mode for preheating the filament, a starting mode for applying a starting voltage for starting and lighting the discharge lamp LA to the discharge lamp LA after preheating, and a steady lighting mode for steady lighting the discharge lamp LA Timer circuit 18, detection circuit 19 that detects a current flowing through the switching element of inverter circuit 13, dimming signal conversion circuit 20 that converts a dimming signal input from the outside into a DC voltage, and an output signal of detection circuit 19 An error amplifier circuit that amplifies an error between the output signal of the light control signal conversion circuit 20 and the output signal to the oscillation circuit 16 And a 1 Tokyo.

  The oscillation circuit 16 determines the inverter frequency by changing the frequency setting signal for setting the inverter frequency for each of the preheating mode, the start mode, and the lighting mode. The inverter frequency determined by the frequency setting signal has a relationship of preheating mode frequency> starting mode frequency> lighting mode frequency. However, the inverter frequency is substantially determined by both the output of the error amplifier circuit 21 and the frequency setting signal in the lighting mode.

This is because the frequency setting signal of the oscillation circuit 16 determines the minimum frequency fmin, and the output signal of the error amplification circuit 21 affects the oscillation circuit 16, thereby making the frequency in the lighting mode higher than the minimum frequency fmin. Because. Thus, in the lighting mode, the inverter current can be fed back to a desired value by changing the dimming signal.
Here, the lowest frequency fmin is set as the first lighting mode frequency, and the frequency determined by both the error amplifying circuit 21 and the frequency setting signal is set as the second lighting mode frequency.

  In the preheating mode and the start mode, the output signal of the error amplifier circuit 21 is fixed to a value that does not affect the oscillation frequency. Therefore, in the preheating mode and the start mode, regardless of the value of the dimming signal, the frequency setting signal of the oscillation circuit 16 changes, thereby releasing a predetermined voltage for starting and lighting the predetermined preheating current through the filament. The inverter can be controlled at an inverter switching frequency determined by applying the voltage to both ends of the lamp LA.

FIG. 2 shows a detailed circuit diagram of a main part of the discharge lamp lighting device 10.
As shown in FIG. 2, an inverter circuit 13 that determines the frequency of the inverter, an error amplifier circuit 21 that is an operational amplifier, and a drive circuit 17 are built in the integrated circuit IC.
The Ho terminal and Lo terminal of the integrated circuit IC are connected to the gate terminals of the high-voltage side FET and the low-voltage side FET in the switching element FET of the inverter circuit 13. The HGND terminal is connected to the source terminal of the high-voltage side FET and the drain terminal of the low-voltage side FET. The LGND terminal is connected to the GND of the inverter circuit 13 in common with the GND terminal of the integrated circuit IC.

  The operating principle of the oscillation circuit 16 is basically the same as that of the discharge lamp lighting device and the discharge lamp lighting device in the lighting fixture including the discharge lamp lighting device described in Patent Document 1, and output signals of the Ho terminal and the Lo terminal. , That is, the inverter frequency is determined by the charge / discharge current (Icvco_so and Icvco_si) at the CVCO terminal of the integrated circuit IC. In the integrated circuit IC, a current mirror circuit is provided in the same manner as the discharge lamp lighting device and the discharge lamp lighting device in the lighting fixture including the discharge lamp lighting device described in Patent Document 1, and charging / discharging of the CVCO terminal is performed. The current is determined by the output current Iout of the RVCO terminal and the mirror ratio. The inverter frequency is set by controlling the output current Iout of the RVCO terminal. When the output current Iout at the RVCO terminal increases, the inverter frequency increases and the lamp output decreases. Unlike this, when the output current Iout at the RVCO terminal decreases, the inverter frequency decreases and the lamp output increases.

here,
VRVCO: RVCO terminal voltage,
VOPout: OPout terminal voltage,
VPREout: PREout terminal voltage
Iout in the preheating mode and the start mode is Irvco + Ipre,
Iout = (VRVCO−VPREout) / Rpre + VRVCO / Rrvco. However, VOPout>VRVCO> VPREout.
The PREout terminal voltage has the same value as the PREin terminal voltage, and the PREin terminal voltage is generated by converting a Duty signal output by the timer circuit 18 (hereinafter also referred to as the microcomputer 18) into a DC voltage DC. Therefore, the inverter frequency is changed by changing the PREin terminal voltage input to the PREin terminal in the preheating mode, the start mode, and the lighting mode. Further, the preheating mode and the starting period are controlled by the microcomputer 18.

The integrated circuit IC, the operational amplifier OP is built, the OP ⁺ terminal, the output signal of the dimming signal converter circuit 20 is inputted, OP ^- the terminal, the source current of the low voltage side FET of the inverter circuit 13 An output signal of the inverter current detection circuit 22 to be detected is input.
Accordingly, the OPout terminal outputs a signal obtained by amplifying the error between the dimming signal and the inverter current, and is connected to the RVCO terminal via the diode C1 and the resistor R1. When the output signal of the dimming signal conversion circuit 20 is lower than the output signal of the inverter current detection circuit 22, the OPout terminal voltage decreases. Further, when the output signal of the dimming signal conversion circuit 20 increases more than the output signal of the inverter current detection circuit 22, the OPout terminal voltage increases.

  Since the output voltage of the DC power supply 12 serving as the power supply for the inverter circuit 13 is constant, the power consumed by the inverter circuit 13 is detected in a pseudo manner by detecting the source current of the FET in the inverter. . Since the increase / decrease in the power consumed by the inverter circuit 13 is correlated with the increase / decrease in the lamp power, the lamp power is artificially fed back to perform the dimming control.

In the preheating mode and the starting mode, the OPout terminal voltage (VOPout) is fixed at the high level H, and VRVCO <VOPout is set. Therefore, the preheating mode and the starting mode are Iout = Irvco + Ipre.
Since VOPout <VRVCO <VPREout in the lighting mode, Iout = Irvco + Iopout. When the OPout terminal voltage decreases, the Iopout current increases, the inverter frequency increases, and the discharge lamp LA is dimmed. As the OPout terminal voltage increases, the Iopout current decreases, the inverter frequency decreases, and the discharge lamp output increases. The feedback operation is performed by the above operation.

Thus, in the discharge lamp lighting device 10, the PREout terminal voltage (VPREout) is the frequency setting signal of the oscillation circuit 16, and the OPout terminal voltage (VOPout) is the output signal of the error amplifier circuit 21.
The discharge lamp lighting device 10 differs from the discharge lamp lighting device described in Patent Document 1 and the discharge lamp lighting device in a lighting fixture including the discharge lamp lighting device in the following two points.

The first difference is that a lamp power feedback circuit is provided.
The second difference is that the OPout terminal voltage (VOPout), which is the output signal of the error amplifier circuit 21, gradually changes when the start mode is switched to the lighting mode, and the inverter frequency changes from the start mode frequency to the second lighting mode frequency. Both the PREout terminal voltage (VPREout) that is the frequency setting signal of the oscillation circuit 16 and the OPout terminal voltage (VOPout) that is the output signal of the error amplifier circuit 21 are changed so that only the increase or the decrease is achieved without increasing or decreasing until. It is a point to do.

FIG. 3 shows the lamp current waveform, inverter frequency, OPout terminal voltage, and PREout terminal voltage in the preheating mode → start mode → lighting mode in the discharge lamp lighting device 10.
As shown in FIG. 3, the inverter frequency is not lower than the frequency in the lighting mode when switching from the start mode to the lighting mode. Therefore, the light output that is the lamp output does not become transiently higher than the light output that is the lamp output in the lighting mode. This is because the PREout terminal voltage (VPREout) in the lighting mode is the same as the value in the start mode during a certain period. Meanwhile, the OPout terminal voltage (VOPout) becomes lower than the VRVCO voltage, the Iopout current increases, and dimming by the operational amplifier OP is started. Until then, the Iopout current does not increase, so the Iout current does not change and remains at the start mode frequency for a certain period. Thereafter, the PREout terminal voltage (VPREout) becomes higher than the VRVCO voltage, and inverter frequency control by Ipre is not performed. Here, when VPREout increases and Ipre becomes zero (0), the current Iout at the RVCO terminal decreases, but the OPout terminal voltage (VOPout) also decreases during this time, so that the lamp current increases. There is no.
Thus, the discharge lamp lighting device 10 can prevent flashing when switching from the start mode to the lighting mode.

  As described above, in the discharge lamp lighting device 10 according to the first embodiment of the present invention described above, the switching frequency in the lighting mode is determined only by the oscillation circuit 16, the first lighting mode frequency, the oscillation circuit 16, and the error amplification circuit 21. In the preheating mode and the start mode, the output signal of the error amplifying circuit 21 is set to a value determined so as not to affect the inverter frequency. The frequency setting signal of the oscillation circuit 16 and the error amplifying circuit 21 are fixed so that the inverter frequency only increases or decreases from the frequency in the starting mode to the second lighting mode frequency when switching from the starting mode to the lighting mode. The output signal of is changed.

  Therefore, the discharge lamp lighting device 10 according to the first embodiment of the present invention does not transiently become a lamp output higher than the Full output when the dimming lamp is started, and is transiently in the starting mode for the dimming start. The light is dimmed without exceeding the light output of the lamp, and the lamp output is not lower than the desired dimming lower limit, so that the lamp can be prevented from extinguishing, and the stress on the lamp filament and the discomfort to the human eye are not given.

  In addition, the discharge lamp lighting device 10 according to the first embodiment of the present invention provides a certain delay time until the frequency setting signal of the oscillation circuit 16 changes when switching from the start mode to the lighting mode, and the error amplification circuit 21. The output signal changes gradually.

  Accordingly, in the discharge lamp lighting device 10 according to the first embodiment of the present invention, the output signal of the error amplifier circuit 21 is gradually changed when switching from the start mode to the lighting mode, so that the extinction does not occur and the oscillation circuit 16 Flash can be easily prevented by simply providing a delay time for the frequency setting signal.

  The luminaire 1 according to the first embodiment of the present invention does not transiently exceed the full output when the dimming lamp is started, and transiently exceeds the light output in the start mode when the dimming is started. Dimming without causing the lamp output to fall below the desired dimming lower limit prevents the lamp from extinguishing, and the discharge lamp lighting device 10 does not cause stress on the lamp filament or cause discomfort to the human eye. The lighting fixture 1 in which the lighting operation of the electric lamp LA is controlled can be provided.

(Second Embodiment)
Next, the lighting fixture provided with the discharge lamp lighting device and discharge lamp lighting device of 2nd Embodiment which concerns on this invention is demonstrated.
In the following embodiments, components that are the same as those in the first embodiment described above or functionally similar components are simplified or omitted by giving the same reference numerals or equivalent symbols in the drawings. To do.

FIG. 4 shows a discharge lamp lighting device according to a second embodiment of the present invention and a discharge lamp lighting device 30 in a lighting fixture equipped with the discharge lamp lighting device. The lamp current waveform, inverter frequency, and OPout in the preheating mode → start mode → lighting mode. The terminal voltage and the PREout terminal voltage are shown.
As shown in FIG. 4, the discharge lamp lighting device 30 is different from the discharge lamp lighting device 10 in the lighting fixture including the discharge lamp lighting device and the discharge lamp lighting device of the first embodiment. The PREout terminal voltage (VPREout), which is a frequency setting signal of the oscillation circuit 16, gradually increases, and the OPout terminal voltage (VOPout), which is an output signal of the error amplifier circuit 21, gradually decreases.

  In the discharge lamp lighting device 10 in the lighting apparatus including the discharge lamp lighting device and the discharge lamp lighting device according to the first embodiment, the PREout terminal voltage suddenly became equal to or higher than the CVCO terminal voltage after a certain period of delay after switching to the lighting mode. However, depending on the design of the feedback time constant and the lamp characteristics, the lamp current may become transiently higher than the lamp current in the start mode.

  Therefore, the discharge lamp lighting device 30 has a transient state due to the fact that both the PREout terminal voltage and the OPout terminal voltage gradually change to a desired value, so that the current Ipre of the PREin terminal suddenly becomes zero (0). Even in the discharge lamp lighting device 30 using the lamp characteristics and the feedback time constant that cannot be realized by the discharge lamp lighting device 10 because there is no decrease in the inverter frequency, it is easy to start in the start mode for a certain period even after the lighting mode transition. The same lamp current as the lamp current can be output.

  Further, the flashlight can be prevented also in the discharge lamp lighting device 30 that performs deep light control. Since the inverter operating frequency is the same as that in the start mode for a certain period when switching from the start mode to the lighting mode, the light output that is the lamp output is also the lamp output (light output in the start mode during the certain period in the lighting mode. This is because it becomes the same as).

In addition, the output signal of the error amplification circuit 21 that is the OPout terminal voltage does not change directly according to the dimming signal as in the discharge lamp lighting device described in Patent Document 1 and the lighting fixture including the discharge lamp lighting device. Without changing as an output voltage signal of the feedback circuit.
Further, since the OP ⁺ signal that is the feedback target signal gradually changes to a desired dimming level, the OPout terminal voltage also gradually changes. Therefore, unlike the discharge lamp lighting device and the lighting fixture provided with the discharge lamp lighting device described in Patent Document 1, there is no transient drop from a desired lamp current.

When the lamp current decreases with respect to the OP ⁺ signal at the desired dimming level, the OPout terminal voltage increases, so that Iopout does not increase any further and the frequency does not increase.
Further, since the OP ⁺ signal gradually changes, feedback control can be accurately performed up to a desired dimming level. Depending on the time constant that controls the feedback speed and the lamp characteristics, if the OP ⁺ signal changes suddenly, the OPout terminal voltage may drop too much, causing the lamp current to drop transiently or to go out. is there.

Since the discharge lamp lighting device 30 has sufficient time for the change of the OP ⁺ signal, the discharge lamp lighting device 30 can perform light control to a desired light control level while performing feedback control.
Therefore, unlike the discharge lamp lighting device and the lighting fixture provided with the discharge lamp lighting device described in Patent Document 1, the discharge lamp lighting device 30 does not cause a transient decrease in the lamp current and the disappearance due thereto.

  As described above, the discharge lamp lighting device 30 has the frequency setting signal of the oscillation circuit 16 and the output signal of the error amplification circuit 21 so that the inverter frequency becomes the frequency of the starting mode for a certain period after the transition from the starting mode to the lighting mode. By gradually changing both, the feeling of strangeness and disappearance due to the flash does not occur.

  The discharge lamp lighting device 30 according to the second embodiment of the present invention gradually changes both the frequency setting signal of the oscillation circuit 16 and the output signal of the error amplifier circuit 21 when switching from the start mode to the lighting mode.

  Therefore, the discharge lamp lighting device 30 according to the second embodiment of the present invention gradually changes both the frequency setting signal of the oscillation circuit 16 and the output signal of the error amplification circuit 21 when switching from the start mode to the lighting mode. Thus, even when the extinction or flash is likely to occur due to the lamp characteristics, or even when the feedback control speed is fast due to the short time constant, the extinction or flash can be prevented.

(Third embodiment)
Next, the lighting fixture provided with the discharge lamp lighting device and discharge lamp lighting device of 3rd Embodiment which concerns on this invention is demonstrated.
The detailed circuit diagram of the principal part of the discharge lamp lighting device 40 in the lighting fixture provided with the discharge lamp lighting device and discharge lamp lighting device of 3rd Embodiment which concerns on FIG. 5 at this invention is shown.

  As shown in FIG. 5, the discharge lamp lighting device 40 is different from the discharge lamp lighting device 30 in the lighting fixture provided with the discharge lamp lighting device and the discharge lamp lighting device of the second embodiment. 41 is provided, and the OPout terminal voltage, which is an output signal of the error amplifier circuit 21, does not fall below a predetermined value for a certain period after switching from the start mode to the lighting mode. The voltage clamped by the lower limit clamp circuit 41 is set by the microcomputer 18.

FIG. 6 shows a lamp current waveform diagram in the discharge lamp lighting device 40 in the lighting apparatus including the discharge lamp lighting device and the discharge lamp lighting device according to the third embodiment of the present invention.
As shown in FIG. 6, the OPout terminal voltage (VOPout) does not fall below a predetermined value for a certain period after the transition to the lighting mode. When the predetermined period is exceeded, the duty signal from the microcomputer 18 gradually decreases, and the lower limit clamp voltage level decreases. As a result, even if the discharge lamp LA is cold and is likely to be extinguished immediately after the dimming start, the dimming level is high and the lamp current is high for a certain period after the transition to the lighting mode. do not do. After a certain period, the coldest spot temperature of the lamp has risen, so that the lamp will not go out even if the dimming is further performed. The level of the dimming lower limit clamp after a certain period of time gradually decreases over, for example, several tens of minutes, so that it is possible to perform dimming deeply without a person recognizing a change in light.

In the discharge lamp lighting device 40 according to the third embodiment of the present invention, the output signal of the error amplifying circuit 21 does not decrease below a predetermined value after switching from the start mode to the lighting mode.
Therefore, the discharge lamp lighting device 40 according to the third embodiment of the present invention prevents the lamp from turning off even when the lamp is likely to turn off when switching from the starting mode to the lighting mode due to variation in component tolerances and temperature characteristics. it can.

  In addition, the lighting fixture provided with the discharge lamp lighting device and the discharge lamp lighting device of the present invention is not limited to the above-described embodiment, and appropriate modifications and improvements can be made.

DESCRIPTION OF SYMBOLS 1 Lighting fixture 10, 30, 40 Discharge lamp lighting device 12 DC power supply 13 Inverter circuit 15 Control circuit 16 Oscillation circuit 18 Timer circuit 19 Detection circuit 21 Error amplification circuit LA Discharge lamp

Claims (4)

DC power supply,
An inverter circuit that converts the DC voltage of the DC power source into a high-frequency voltage by switching with a switching element and supplies the voltage to the discharge lamp;
And a control circuit for controlling the output of said inverter circuit,
The control circuit includes:
A detection circuit for detecting a discharge lamp current of the discharge lamp or an inverter current flowing in the inverter circuit and outputting a detection signal;
An error amplifying circuit for amplifying an error between a target value for setting the discharge lamp current or the inverter current to a desired value and a detection value of the detection signal;
A preheating mode in which the filament electrode included in the discharge lamp is preheated for a predetermined time before the discharge lamp is turned on, and a starting voltage for starting the discharge lamp for a predetermined time after preheating the filament electrode of the discharge lamp. A timer circuit that controls switching to a lighting mode in which the discharge lamp is steadily turned on after the start-up lighting of the discharge lamp,
In response to said timer circuit to change the frequency setting signal, the preheating mode, the starting mode, anda oscillating circuit for determining the switching frequency of the inverter circuit in the lighting mode,
The switching frequency of the inverter circuit in the lighting mode is a first lighting mode frequency determined only by the oscillation circuit, and a second lighting mode frequency determined by both output signals of the oscillation circuit and the error amplification circuit. In the preheating mode and the start mode, the output signal of the error amplifier circuit is fixed to a value determined so as not to affect the switching frequency of the inverter circuit , and the output signal from the start mode is at the lighting Modohe switching, only increased the frequency of switching frequency in the starting mode of the inverter circuit to the second lighting mode frequencies, or, so that a decrease only, the error amplifier and the frequency setting signal of the oscillation circuit Change the output signal with the circuit ,
When switching from the starting mode to the lighting mode, a certain delay time is provided until the switching frequency of the inverter circuit changes,
The output signal of the error amplifier circuit gradually changes immediately after switching to the lighting mode,
When the delay time has elapsed, the error amplifier based on the output signal of the circuit, the detection signal of the detection value discharge lamp lighting device feedback control that is performed so as to come close to the target value. In the discharge lamp lighting device according to claim 1 ,
When switching from the starting mode of the lighting Modohe gradually altered so that discharge lamp lighting device a frequency setting signal of the oscillation circuit. In the discharge lamp lighting device according to claim 1 or 2 ,
After switching from the starting mode of the lighting Modohe, the output signal of said error amplification circuit, a period of time, not drop below a defined value discharge lamp lighting device. Luminaire comprising a discharge lamp lighting device according to any one of claims 1 to 3, a discharge lamp lighting operation is controlled by the discharge lamp lighting device.

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