JP2007149408A - Discharge lamp lighting device and luminaire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To smoothly change a light output to a prescribed output determined by a light control signal after starting a discharge lamp by inhibiting the discharge lamp from flashing for a moment, when lighting the discharge lamp by starting it in a light control state. <P>SOLUTION: This discharge lamp lighting device is equipped with an output detecting means to detect an output supplied to a discharge lamp La connected to an output of an inverter circuit 1 through a resonance circuit 2, a feedback control means 5 to make the output variable so that the detected value becomes almost identical to a light control command value voltage Vref, and a pulse starting voltage impressing means 6 to impress periodic pulsed high voltages on both ends of the lamp during the starting voltage impressing period of the discharge lamp. A pulse amplitude reducing period to gradually reduce the amplitude of the pulsed high voltage is provided after the end of the starting voltage impressing period, and the detected value of the output detecting means 3 during the starting voltage impressing period is made lower than the light control command value voltage Vref. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a discharge lamp lighting device and a lighting fixture using an inverter circuit.

  For example, as a discharge lamp dimming device for dimming a discharge lamp typified by a fluorescent lamp, the discharge lamp is lit at a high frequency using an inverter circuit that converts a low-frequency commercial power supply voltage into a high-frequency voltage, and the input dimming A dimming electronic ballast that performs dimming of the discharge lamp by controlling the power supplied to the discharge lamp in accordance with a signal has become common. Such a light control electronic ballast is required to have a stable light control performance that does not cause an unstable state such as flicker even to a low luminous flux.

  In order to meet these requirements, dimming electronic ballasts that detect the lighting state of a discharge lamp and perform feedback control so that the discharge lamp has a predetermined output in accordance with an input dimming signal are generally used. It is. As a method using such feedback control, a method of detecting output power to the discharge lamp and performing feedback control, a method of detecting output current to the discharge lamp and performing feedback control, and the like are generally used.

  FIG. 11 shows an example of a dimming electronic ballast using a method of detecting output power to the discharge lamp and performing feedback control. Such a ballast can be configured using, for example, an integrated circuit L6574 manufactured by STMicroelectronics, and a configuration of a dimming electronic ballast using the integrated circuit in its application note (AN993). An example is given.

  In FIG. 11, the AC power source AC is full-wave rectified by a full-wave rectifier circuit DB, and further an AC / DC converter (indicated by an inductor L1, a switching element Q1, a diode D1, a smoothing capacitor C1, and a PFC control circuit 7). The step-up chopper circuit) obtains a predetermined DC voltage Vdc across the smoothing capacitor C1.

  The voltage Vdc across the smoothing capacitor C1 is converted into a high-frequency rectangular wave voltage by the half-bridge type DC / AC inverter circuit 1 composed of switching elements Q2 and Q3 that are alternately turned on and off by the inverter drive circuit 63. In addition, a substantially sinusoidal high-frequency voltage is supplied to the discharge lamp La via the resonance circuit 2 including the inductor L2 and the capacitors C2 and C3, and the discharge lamp La is started and lit at a high frequency. Yes.

  Here, the discharge lamp La is a hot cathode type fluorescent lamp having a filament at each electrode, and a current is supplied to each filament of the discharge lamp La to preheat to heat the filament to an appropriate temperature. A circuit 8 is connected.

  Also, the current flowing through one switching element (Q3 in FIG. 11) of the switching elements Q2 and Q3 that alternately turn on and off constituting the inverter circuit 1 is detected by the resistor R1. The detection voltage detected by the resistor R1 is input to the inverting input terminal of the operational amplifier OP1 for feedback control via the resistor R2. The input detection voltage is averaged by a feedback capacitor C4 connected to the operational amplifier OP1, and compared with a non-inverting input terminal voltage of the operational amplifier OP1, in this case, a command value voltage Vref determined by the dimming signal 4, thereby providing the operational amplifier OP1. Output voltage changes.

  Here, the drive frequency control circuit 62 operates such that the drive frequency decreases and the output of the discharge lamp La increases when the output voltage of the operational amplifier OP1 increases, and the drive frequency decreases when the output voltage of the operational amplifier OP1 decreases. By operating so as to increase and decrease the output of the discharge lamp La, the output to the discharge lamp La is feedback-controlled so that the average value of the detected voltage and the command value voltage Vref are substantially the same.

  Since the DC voltage Vdc generated across the smoothing capacitor C1 is substantially constant, the output power of the inverter circuit 1 is equivalently controlled by feedback control of the average value of the current flowing through the switching element Q3. . That is, by changing the command value voltage Vref according to the input dimming signal 4, the output power of the inverter circuit 1 can be varied and the discharge lamp La can be dimmed according to the dimming signal 4.

  Next, the operation in the case of starting the discharge lamp La in the dimming state in the conventional example will be described with reference to FIG. In FIG. 12, Vla is a voltage applied to both ends of the discharge lamp La, finv is a drive frequency of the inverter circuit 1, OPout is an output terminal voltage of the operational amplifier OP1, and OPin is two input terminal voltages of the operational amplifier OP1.

  As shown in FIG. 12, first, the preheating circuit 8 preheats the filament of the discharge lamp La for a predetermined time (Tph) in a state where a low lamp voltage Vla that does not start discharge is applied to the discharge lamp La. After heating the filament to a temperature sufficient to start the discharge, a starting voltage Vla for starting the discharge lamp La is gradually applied to the discharge lamp La.

  Here, since the discharge lamp La is not turned on until the discharge lamp La is started, the average value of the detection voltages detected by the detection resistor R1 rather than the command value voltage (OP + = Vref) determined by the dimming signal. (OP−) is lower, and the output voltage OPout of the operational amplifier OP1 operates to maximize the output, that is, the output of the discharge lamp La.

  Next, when the starting voltage Vla reaches the discharge start voltage of the discharge lamp La, the discharge lamp La is started. At this time, since the output voltage OPout of the operational amplifier OP1 is the maximum value, the discharge lamp La is dimmed. Attempts to light at a higher output than the predetermined output determined by For this reason, the average value (OP−) of the detection voltage detected by the detection resistor R1 is higher than the command value voltage Vref determined by the dimming signal, and the output voltage OPout of the operational amplifier OP1 is determined by the capacitor C4 and the resistor R2. The output of the discharge lamp La is decreased until the average value (OP−) of the detection voltage detected by the detection resistor R1 and the command value voltage Vref become substantially the same, and decreases by a predetermined time constant, and is determined by a dimming signal. The output power to the discharge lamp La is fed back so as to maintain a predetermined output.

  From the above operation, immediately after the discharge lamp La is started, light that is brighter than a predetermined light output determined by the dimming signal is generated for a moment and appears to be flashing, so that the user is uncomfortable. there were.

Further, as a method of reducing flash light (so-called on-pica) when starting the discharge lamp, a method of applying a periodic pulse voltage to the discharge lamp and lighting the discharge lamp with a low luminous flux is disclosed in JP-A-8-321391, etc. Proposed in However, even when the discharge lamp is started with a periodic pulse voltage, the light may vary depending on the characteristics of the discharge lamp and the ambient temperature of the discharge lamp when the pulse voltage is reduced or removed after starting the discharge lamp. There was a problem that the output fluctuated and flickered.
JP-A-8-321391

  The present invention has been made in view of the above points. The purpose of the present invention is to generate a flashing light that makes the discharge lamp shine brightly for a moment when the discharge lamp is started and lit in a dimming state. It is an object of the present invention to provide a discharge lamp lighting device and a lighting fixture that can start the discharge lamp so as to smoothly change to a predetermined light output determined by the dimming signal after the discharge lamp is started.

  In the present invention, in order to solve the above-described problem, as shown in FIG. 1, an inverter circuit 1 that converts a DC power supply voltage Vdc into a high-frequency voltage, and at least an output terminal connected to the inverter circuit 1 are used. A resonance circuit 2 including one inductor L2 and capacitors C2 and C3, and output detection means 3 for equivalently detecting power or current supplied to the discharge lamp La connected to the output terminal of the resonance circuit 2, The detection value of the output detection means 3 is compared with the dimming command value voltage Vref that is varied according to the input dimming signal 4, and the detection value of the output detection means 3 and the dimming command value voltage Vref are compared. In the discharge lamp lighting device including the feedback control means 5 that varies the output to the discharge lamp La so that they are substantially the same, a starting voltage application period for starting the discharge lamp La (FIG. 2). Pulse starting voltage applying means 6 for applying a periodic pulsed high voltage to both ends of the discharge lamp La at Tst), and gradually increasing the pulse amplitude of the pulsed high voltage after the end of the starting voltage application period Tst. And a detected value of the output detecting means 3 in the starting voltage application period Tst is lower than the dimming command value voltage Vref. is there.

  The present invention comprises pulse starting voltage applying means for applying a periodic pulse voltage to a discharge lamp to start the discharge lamp at a light output below the dimming lower limit, and further gradually increasing the pulse voltage amplitude after starting the discharge lamp. Generation of flashing light that causes the discharge lamp to shine brightly for a moment when the discharge lamp is started by using both a means for reducing the output and a feedback control means for feedback controlling the discharge lamp output so that the output of the discharge lamp becomes a predetermined value determined by the dimming signal The discharge lamp can be started smoothly so that the light output becomes a predetermined light output determined by the dimming signal.

  Further, the command value for feedback control is set to be larger than the command value at the lower limit of dimming before starting the discharge lamp, and the command value is dimmed as the pulse voltage amplitude is gradually decreased after starting the discharge lamp. By providing means for gradually lowering to the lower limit command value, there is an effect that it is possible to provide a lighting apparatus capable of smoothly starting the discharge lamp while suppressing the light output fluctuation at the start due to the error of the feedback control circuit.

Embodiments of the present invention will be described below.
(Embodiment 1)
FIG. 1 shows a circuit configuration of Embodiment 1 of the present invention. Note that parts having the same functions as those in FIG. 11 described in the background art are denoted by the same symbols and names, and the description of the operation is omitted. As shown in FIG. 1, the present embodiment is provided with a pulse control circuit 61 for periodically modulating the frequency of the drive frequency control circuit 62 in the configuration of the background art of FIG.

  Here, the pulse control circuit 61 outputs to the drive frequency control circuit 62 a pulse control signal whose signal periodically increases. The drive frequency control circuit 62 periodically decreases the drive frequency as the pulse control signal is periodically increased, and tries to periodically increase the output of the discharge lamp La. Thus, when starting the discharge lamp La, a high voltage is periodically applied to both ends of the discharge lamp La, so that the discharge lamp La is started with a periodic pulse voltage.

  Next, in the present embodiment, an operation when the discharge lamp La is started in a dimming state will be described. As shown in FIG. 2, first, the filament of the discharge lamp La is preheated by the preheating circuit 8 for a predetermined time (Tph) in a state where a lamp voltage Vla that is low enough not to start discharge is applied to the discharge lamp La.

  After heating the filament to a temperature sufficient to start discharge, in order to start the discharge lamp La, a pulsed start voltage Vla having a high peak value and a low effective value is gradually applied to the discharge lamp La.

  Here, since the discharge lamp La is not lit until the discharge lamp is started, the average value of the detection voltages detected by the detection resistor R1 (OP + = Vref) determined by the dimming signal (OP + = Vref). OP−) is lower, and the output voltage OPout of the operational amplifier OP1 operates to maximize the output, that is, the output of the discharge lamp La.

  Next, when the peak value of the start pulse voltage Vla reaches the discharge start voltage of the discharge lamp La, the discharge lamp La starts. However, since the effective value over one period of the pulse voltage applied to the discharge lamp La is low, the discharge lamp La starts with an illuminance lower than the set illuminance at the lower limit of dimming. Therefore, even after the discharge lamp La starts to start, the average value (OP−) of the detection voltage detected by the detection resistor R1 is lower than the command value voltage (OP + = Vref), and the output voltage OPout of the operational amplifier OP1. Will continue to maintain the maximum value.

  Next, after applying the start pulse voltage for a predetermined time (Tst), the pulse control signal Vpls output from the pulse control circuit 61 is controlled so that the pulse signal amplitude gradually decreases over time Tswp1. The

  Here, as shown in FIG. 2, the pulse control signal Vpls is obtained by gradually decreasing the pulse amplitude and decreasing the drive frequency finv of the inverter circuit 1 by increasing the voltage that determines the base value of the pulse. While gradually reducing the pulse amplitude of the pulse voltage applied to the discharge lamp La, the output to the discharge lamp La is gradually increased.

  When the average value (OP−) of the detection voltage detected by the detection resistor R1 reaches the command value voltage (OP + = Vref) as the output of the discharge lamp La increases, the operational amplifier OP1 starts a feedback operation, and the pulse voltage decreases. Along with this, the output voltage OPout of the operational amplifier OP1 is gradually lowered to perform feedback control so that the output of the discharge lamp La maintains a predetermined value determined by the dimming signal. Here, it is necessary to set the time Tswp1 that is slower than the response time of the feedback control so that the feedback voltage control by the operational amplifier OP1 follows the change.

  Next, when the time Tswp1 elapses and the reduction of the pulse amplitude is completed, the mode shifts to the normal lighting mode. Although FIG. 2 shows an operation example in the case where a pulse voltage is applied to the discharge lamp La even in the normal lighting mode, the pulse voltage in the lighting mode may be completely removed.

  According to the present embodiment, when the discharge lamp starts to start, no flash light exceeding the set illuminance occurs, and the illuminance is set even when the pulse voltage is reduced or removed after the discharge lamp starts to start. Never exceed the value. Also, by controlling the output when the pulse voltage is reduced by feedback control, the brightness can be changed depending on the characteristics of the discharge lamp and the ambient temperature of the discharge lamp, and the discharge lamp can be started smoothly without flickering. A discharge lamp lighting device can be provided.

(Embodiment 2)
An operation explanatory diagram of the second embodiment of the present invention is shown in FIG. The operation of this embodiment differs from that of Embodiment 1 in that the command value voltage (OP + = Vref) applied to the non-inverting input terminal of the operational amplifier OP1 is adjusted during the period Tst during which the starting pulse voltage is applied to the discharge lamp La. The offset voltage is provided so as to be larger than the command value voltage determined by the optical signal. Further, the offset voltage is controlled to gradually decrease as the pulse amplitude decreases in the start pulse reduction period Tswp1 and gradually decreases to the command value voltage determined by the dimming signal 4. .

  Usually, the commercial input voltage AC is an AC voltage of 100V or 200V. For this reason, the output DC voltage Vdc of the step-up chopper circuit generated at both ends of the electrolytic capacitor C1 is often set to about 400V. Further, as the detection resistor R1, a resistance value of about 1 to several ohms is selected in order to reduce power loss. Therefore, particularly when the discharge lamp La is dimmed to about 5% of the rated output, for example, the average value of the detection voltage generated at both ends of the detection resistor R1 is a very small voltage of about several tens mV (millivolt). Signal.

  On the other hand, it is generally known that an ordinary operational amplifier generates an input offset voltage at an input terminal, unlike an ideal operational amplifier. This offset voltage causes an error in the actual feedback operation. Although this offset voltage depends on the type of the operational amplifier, it is usually about several mV to several tens of mV, and the influence on the detection voltage by the detection resistor R1 cannot be ignored at the time of low luminous flux dimming with a small discharge lamp power. .

  In particular, in the pulse voltage amplitude reduction period Tswp1 in the first embodiment, the output voltage OPout of the operational amplifier OP1 greatly fluctuates. Therefore, it becomes difficult to maintain the output at a predetermined value due to this offset voltage, and the output fluctuates due to a feedback error. By doing so, it flickers and a smooth start cannot be performed.

  Therefore, in the present embodiment, when the discharge lamp La is dimmed to a low luminous flux such as 5% of the rated power, for example, a command given to the non-inverting input terminal of the operational amplifier OP1 during the period Tst during which the starting pulse voltage is applied to the discharge lamp La. An offset voltage is provided so that the value voltage (OP + = Vref) is larger than the command value voltage determined by the dimming signal 4, and an error due to the input offset voltage of the operational amplifier OP1 is corrected, and in the start pulse reduction period Tswp1 The offset voltage is gradually decreased as the pulse amplitude is reduced, and gradually decreased within the period Tswp1 to the command value voltage finally determined by the dimming signal, and smoothly to the optical output finally determined by the dimming signal 4 The light output is changed.

  According to the present embodiment, particularly when the discharge lamp is dimmed to a low luminous flux, for example, 5% of the rated power, when the discharge lamp starts to start, no flash exceeding the set illuminance is generated, and the discharge lamp Even when the pulse voltage is reduced or removed after the start of the lamp, the illuminance does not fluctuate greatly due to the feedback error of the operational amplifier, and the discharge lamp lighting device can start the discharge lamp smoothly without causing flicker Can be provided.

(Embodiment 3)
An operation explanatory diagram of the third embodiment of the present invention is shown in FIG. The operation of the present embodiment differs from the operation of the second embodiment in that the command value voltage of the operational amplifier OP1 is such that the illuminance at the end of the pulse voltage amplitude reduction period Tswp1 becomes the lower limit illuminance in the dimming range in which the discharge lamp can be dimmed. Vref is controlled, and after the end of the pulse voltage amplitude reduction period Tswp1, the command value voltage Vref of the operational amplifier OP1 is controlled to gradually increase over a predetermined time Tswp2 to the command value voltage determined by the dimming signal 4 It is.

  According to the present embodiment, since the time Tswp1 from the end of the start pulse voltage application period to the arrival of the lower limit illuminance is fixed, the optimal start pulse voltage amplitude reduction time can always be secured with respect to the response time of the operational amplifier OP1. .

  Furthermore, since the light output gradually increases from the lower limit illuminance to the set illuminance determined by the dimming signal, the light output does not change abruptly, it can be started smoothly to the set illuminance, and visual discomfort due to the sudden change in light output Can be reduced.

  The period Tswp2 during which the command value is increased is not a fixed time, but is controlled so that the time is long when the target set illuminance is high and the time is short when the set illuminance is low. In addition to being able to start smoothly, it is possible to obtain the advantage of quickly reaching the set illuminance during dimming. In this way, the dimming command value variable period Tswp2 is preferably controlled so that the time varies depending on the dimming signal input.

(Embodiment 4)
A circuit diagram of a fourth embodiment of the present invention is shown in FIG. 5, and an operation explanatory diagram is shown in FIG. The circuit diagram (FIG. 5) of the present embodiment is different from the circuit diagram (FIG. 1) shown in the first embodiment in that it includes a lighting detection circuit 9 for detecting that the discharge lamp La has started discharging. is there.

  Although a detailed description of the specific configuration of the lighting detection circuit 9 is omitted, for example, changes in the discharge lamp current, the discharge lamp power, the discharge lamp voltage, the discharge lamp equivalent resistance value, the discharge lamp light output, etc. before and after the discharge of the discharge lamp La is started. In addition, any configuration may be used as long as it detects a change in another electrical signal accompanying these changes.

  Next, the operation at the start of the discharge lamp La will be described with reference to FIG. The operation of the present embodiment is different from the operation of the second embodiment in that the start pulse application period Tst to the discharge lamp La ends after detecting that the discharge lamp La has started to discharge by the lighting detection circuit 9, and starts. The pulse voltage amplitude is reduced to the period Tswp1.

  According to the present embodiment, for example, at a normal temperature at which the discharge lamp La is likely to be lit, the discharge lamp La starts discharging relatively quickly, so that the start pulse application period Tst can be shortened. Thereby, it is possible to shorten the time until the set illuminance is reached. In addition, at a low temperature at which the discharge lamp La is difficult to light, it is possible to ensure the start of the discharge lamp La by applying the start pulse voltage until the discharge lamp La starts to discharge.

(Embodiment 5)
A circuit diagram of a fifth embodiment of the present invention is shown in FIG. 7, and an operation explanatory diagram is shown in FIG. The circuit diagram (FIG. 7) of the present embodiment is different from the circuit diagram (FIG. 1) shown in the first embodiment in that the load abnormality detection unit 10 that detects abnormality of the discharge lamp La and the load abnormality detection unit 10 The detection mask means 11 for invalidating the abnormality detection signal is provided.

  Although a detailed description of the specific configuration of the load abnormality detection means 10 is omitted, in general, by detecting an abnormal increase in the discharge lamp voltage or an abnormal increase in the DC voltage component of the discharge lamp voltage, the discharge lamp La is detected. A circuit that detects the end-of-life condition is used. Also, when a load abnormality such as the end of life is detected by the load abnormality detection means 10, the drive frequency control circuit 62 stops driving the inverter circuit 1 or reduces the output power to the load. It is.

  Next, the operation of this embodiment will be described with reference to FIG. As shown in FIG. 8, the abnormality detection signal from the load abnormality detection means 10 is invalidated by the detection mask means 11 at least during the start pulse application period Tst and the start pulse voltage amplitude reduction period Tswp1.

  For example, when an abnormal rise in the discharge lamp voltage is detected as the load abnormality detection means 10, a start pulse voltage having a peak value higher than that during lighting is applied to the discharge lamp La during the start pulse application period Tst. Even if it is a normal discharge lamp, there is a high possibility that the load abnormality detecting means 10 malfunctions. In the start pulse voltage amplitude reduction period Tswp1, the peak value of the pulse voltage gradually decreases, but a voltage having a higher peak value than that during lighting is applied to the discharge lamp La.

  Further, for example, even when detecting an abnormal rise in the DC voltage component of the discharge lamp voltage, the lighting is performed with an illuminance lower than that at the dimming lower limit in the start pulse application period Tst and the start pulse voltage amplitude reduction period Tswp1. Therefore, the impedance of the discharge lamp is very high, and there is a high possibility that a relatively high DC voltage component is generated in the discharge lamp voltage even in a normal discharge lamp.

  Therefore, by providing the detection mask means 11 that invalidates the detection output of the load abnormality detection means 10 during these periods, erroneous detection in the starting process of the discharge lamp La is prevented, and the discharge lamp La is reliably started. Can do.

(Embodiment 6)
FIG. 9 shows a circuit diagram of the sixth embodiment of the present invention. The circuit diagram (FIG. 9) of the present embodiment shows a specific configuration of the preheating circuit 8 in the circuit diagram (FIG. 1) of the first embodiment. As a configuration of the preheating circuit 8, generally, a part of the current flowing through the resonance system circuit is passed through the filament, or a secondary winding is provided in the inductor L2 constituting the resonance system, and current is supplied to each discharge lamp filament. There is a method to do. However, in the method of supplying current to the filament from a part of the resonant circuit for lighting such a discharge lamp, the filament current also periodically increases when a periodic pulse voltage is applied to the discharge lamp. However, it is conceivable that the filament is heated more than necessary, causing problems such as shortening the life of the discharge lamp.

  Therefore, in the present embodiment, as shown in FIG. 9, a series circuit of a new primary winding N1 of a transformer T1 and a DC cut capacitor C5 is connected to the output terminal of the inverter circuit 1, and the transformer T1. The two secondary windings N2 and N3 are supplied with preheating current to the filaments of the discharge lamp La via capacitors C6 and C7, respectively.

  According to the present embodiment, since the preheating circuit configured by the transformer T1 is not affected by the resonance circuit, the preheating current periodically increases even when a pulse voltage is applied to the discharge lamp, and a filament is required. It can suppress that it heats above, and can prevent that the lifetime of a discharge lamp becomes short.

(Embodiment 7)
An operation explanatory diagram of the seventh embodiment of the present invention is shown in FIG. In the present embodiment, an operation for smoothly turning off the discharge lamp La when a turn-off signal instructing turn-off of the discharge lamp La is input as the dimming signal 4 is added. As shown in FIG. 10, when a turn-off signal is input, a pulse voltage amplitude increase period Tswp3 is provided in which the pulse voltage amplitude is gradually increased from the lower limit illuminance state. Thereby, since the discharge lamp La gradually decreases from the lower limit illuminance to a lower illuminance, there is no sense of incongruity due to a sudden change in light output when the discharge lamp La is turned off, and the discharge lamp La can be turned off smoothly.

  Note that the command value voltage Vref of the operational amplifier OP1 in the pulse voltage amplitude increase period Tswp3 is gradually decreased so as to further decrease from the command value voltage at the lower limit as shown in FIG. 10 in order to reduce the discharge lamp illuminance to a lower illuminance. It may be changed.

  In FIG. 10, after the discharge lamp is completely extinguished, the inverter circuit 1 is intermittently operated to intermittently continue the supply of the preheating current to the filament of the discharge lamp La. . If the same preheating current as the preheating current before starting the discharge lamp La is continuously supplied to the filament, the filament is heated more than necessary, the filament portion becomes red hot and emits light, and the life of the discharge lamp La is shortened. Trouble occurs.

  Therefore, by intermittently continuing the supply of the preheating current to the filament, the filament is continuously heated with a preheating current that is lower in average than the preheating current at the start of the discharge lamp La, and the filament starts the discharge lamp La. Therefore, it can be kept at an appropriate temperature. Thereby, when the lighting signal is input next, the start pulse application period Tst can be shifted to without starting the preceding preheating period Tph in FIG. 2, and the discharge lamp La is started together with the input of the lighting signal. The discharge lamp La can be started immediately without causing a delay. In addition, by operating intermittently, there is an effect that power consumption during preheating can be reduced.

(Embodiment 8)
This embodiment relates to a lighting fixture applicable to the first to seventh embodiments, and although not shown in the drawings, the discharge lamp lighting device of any of the above-described embodiments is housed in the fixture body as a dimming electronic ballast. And the lighting fixture which lights the discharge lamp with which it mounted | worn between the sockets arrange | positioned at the both ends of the lower surface of a fixture main body is comprised. Of course, in the case of lighting fixtures for two or more lamps, the number of discharge lamp lighting devices accommodated in the fixture body may be made to correspond to the number of discharge lamps.

It is a circuit diagram of a 1st embodiment of the present invention. It is operation | movement explanatory drawing of the 1st Embodiment of this invention. It is operation | movement explanatory drawing of the 2nd Embodiment of this invention. It is operation | movement explanatory drawing of the 3rd Embodiment of this invention. It is a circuit diagram of a 4th embodiment of the present invention. It is operation | movement explanatory drawing of the 4th Embodiment of this invention. It is a circuit diagram of a 5th embodiment of the present invention. It is operation | movement explanatory drawing of the 5th Embodiment of this invention. It is a circuit diagram of a 6th embodiment of the present invention. It is operation | movement explanatory drawing of the 7th Embodiment of this invention. It is a circuit diagram of a conventional example. It is operation | movement explanatory drawing of a prior art example.

Explanation of symbols

La discharge lamp 1 inverter circuit 2 resonance circuit 3 output detection means 4 dimming signal 5 feedback control means 6 pulse starting voltage application means 61 pulse control circuit 62 drive frequency control circuit 63 inverter drive circuit OP1 operational amplifier Vref dimming command value voltage 7 PFC Control circuit 8 Preheating circuit 9 Lighting detection circuit 10 Load abnormality detection means 11 Detection mask means

Claims (10)

An inverter circuit for converting a DC power supply voltage into a high-frequency voltage;
A resonant circuit including at least one inductor connected to the output terminal of the inverter circuit and a capacitor;
Output detecting means for equivalently detecting power or current supplied to a discharge lamp connected to the output end of the resonant circuit;
The detection value of the output detection means is compared with the dimming command value voltage that is varied according to the input dimming signal, and the detection value of the output detection means and the dimming command value voltage are substantially the same. In a discharge lamp lighting device comprising feedback control means for varying the output to the discharge lamp as described above,
Pulse starting voltage applying means for applying a periodic pulsed high voltage to both ends of the discharge lamp in a starting voltage application period for starting the discharge lamp;
After the start voltage application period ends, the pulse amplitude of the pulsed high voltage is gradually decreased, and the detection value of the output detection means in the start voltage application period is the dimming command value voltage. The discharge lamp lighting device characterized by being lower than the above. 2. The discharge lamp lighting device according to claim 1, wherein the dimming command value voltage in the start voltage application period is greater than the dimming command value voltage at the dimming lower limit. 3. The discharge lamp lighting device according to claim 2, wherein the dimming command value voltage during the starting voltage application period is gradually lowered to the dimming command value voltage at the dimming lower limit during the pulse amplitude reduction period. . The discharge lamp lighting device according to any one of claims 1 to 3, wherein the time of the pulse amplitude reduction period is set such that the reduction of the pulse amplitude is slower than the response of the feedback control means. . The dimming command value variable period in which the dimming command value voltage gradually changes to the dimming command value voltage determined by the inputted dimming signal after the end of the pulse amplitude reduction period is provided. The discharge lamp lighting device according to any one of 1 to 4. 2. A lighting detection circuit for detecting that the discharge lamp has started to discharge, and receives a signal from the lighting detection circuit and shifts from the start voltage application period to the pulse amplitude reduction period. The discharge lamp lighting device in any one of -5. An abnormality detection circuit for detecting an abnormality of the discharge lamp is provided, and abnormality detection invalidating means for invalidating the abnormality detection circuit is provided at least during the start voltage application period and the pulse amplitude reduction period. Item 7. A discharge lamp lighting device according to any one of Items 1 to 6. The discharge lamp is a hot cathode fluorescent lamp having a filament on each electrode, and a primary winding of a transformer for preheating a filament having a plurality of secondary windings connected to the filaments is connected to the inverter circuit. The discharge lamp lighting device according to claim 1, wherein the discharge lamp lighting device is connected to an output end. When a signal instructing extinction of the discharge lamp is input as the dimming signal, the pulse amplitude of a periodic pulsed high voltage applied to both ends of the discharge lamp is gradually increased from the dimming lower limit state. The discharge lamp lighting device according to any one of claims 1 to 8, wherein the discharge lamp is extinguished after a pulse amplitude increase period. A lighting fixture comprising the discharge lamp lighting device according to any one of claims 1 to 9.

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