JP2007042576A - Discharge lamp lighting device, lighting device, and lighting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device for light controlling a discharge lamp which can control lighting stably without having a defect such as flickering and turning-out by suppressing fluctuations in discharge lamp output even in the case the ambient temperature has dropped. <P>SOLUTION: The discharge lamp lighting device lights the discharge lamp DL through a resonant circuit 5 by a high frequency voltage of an inverter part 4. The lighting device comprises an output detecting means R1 for detecting an electric output of the discharge lamp DL, a light-control signal generation circuit 9 which establishes a light-control instruction value according to the light control signal input, and a feedback control means B which compares and calculates a detected signal output from the output detecting means R1 and the light-control instruction value output from the light-control signal generation circuit 9 and changes an On-Off signal generated by an inverter control means A according to the calculation result. Furthermore, a pulse voltage superposing means C which impresses a pulsating high voltage on the discharge lamp DL with a prescribed period is provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a discharge lamp lighting device capable of dimming and lighting a discharge lamp, an illumination device using the same, and an illumination system.

  Conventionally, as a dimming ballast for a discharge lamp typified by a fluorescent lamp, the discharge lamp is turned on at a high frequency using an inverter circuit that converts a low-frequency commercial AC power source into a high frequency, and according to the dimming signal input A dimming electronic ballast for dimming a discharge lamp by controlling the power supplied to the discharge lamp has become common. Such an electronic ballast for dimming is required to obtain a stable dimming performance that does not cause instability such as variations in light output and flickering even to a lower luminous flux.

  In order to meet this requirement, an electronic ballast that detects the lighting state of a discharge lamp (for example, a fluorescent lamp) and performs feedback control so that the discharge lamp has a predetermined output in accordance with an input dimming signal is generally used. Is. As a method using such feedback control, one that detects a current flowing through a discharge lamp and performs feedback control so as to obtain a predetermined current value according to a dimming signal is generally used. JP-A-6-302393) also discloses related technology.

  In addition, a method of detecting output power to the discharge lamp and performing feedback control is generally used. For example, related technology is disclosed in Japanese Patent Laid-Open No. 6-311753, and integration of ST Microelectronics, Inc. A configuration example of a dimming electronic ballast using the circuit L6574 is also described in the company's application note (AN993: Electronic Ballast with PFC using L6574 and L6561).

  Next, a specific example of an electronic ballast that detects the output power to the discharge lamp and performs feedback control will be described with reference to FIG. In FIG. 13, the input AC voltage AC is full-wave rectified by a diode bridge DB, and a predetermined DC voltage Vdc is obtained across the capacitor C1 by a chopper circuit including an inductor L1, a switching element Q1, a diode D1, and a capacitor C1. . The inverter circuit including the switching elements Q2 and Q3 and the capacitor C3 converts the DC voltage Vdc into a high-frequency AC voltage by switching the DC voltage Vdc at a high frequency with the switching elements Q2 and Q3.

  Here, the resistor R1 detects the current flowing through the switching element Q3, and equivalently detects the power output from the inverter circuit based on the average value of the detected current. In addition, the load circuit including the inductor L2, the capacitor C2, and the discharge lamp DL converts the high-frequency AC voltage converted by the inverter circuit into a substantially sine wave shape by the resonance of the inductor L2 and the capacitor C2, and supplies the discharge lamp DL with a predetermined voltage. It supplies power.

  In the circuit of FIG. 13, the inverter output power detected by the resistor R1 is input to the inverting input terminal (−) of the operational amplifier OP1 via the resistor R2, and the command value voltage Vref is input to the non-inverting input terminal (+) of the operational amplifier OP1. Is input. The operational amplifier OP1 compares the two input signals and changes the output voltage of the operational amplifier OP1 so that the error is reduced. The output terminal of the operational amplifier OP1 is connected to the voltage controlled oscillator VCO, and the output power of the inverter circuit is varied by varying the drive frequency of the inverter circuit according to the output voltage of the operational amplifier OP1, and the inverter circuit detected by the resistor R1 The feedback operation is performed so that the output power becomes substantially the same as the target power corresponding to the command value voltage Vref.

  By varying the command value voltage Vref according to the input dimming signal, it is possible to adjust the output power of the inverter circuit to a desired value according to the dimming signal. In this way, in an electronic ballast equipped with feedback control, for example, even when the characteristics of the discharge lamp change due to variations in the characteristics of the discharge lamp or changes in the ambient temperature, substantially constant power is supplied to the discharge lamp. There is an advantage that you can.

  Here, FIG. 14 shows a graph of lamp current-lamp voltage characteristics when a FHF32 fluorescent lamp manufactured by Matsushita Electric Industrial Co., Ltd. is dimmed in an environment of ambient temperatures of 25 ° C. and 5 ° C. In order to dim the FHF32 fluorescent lamp to a dimming ratio of about 25%, the lamp current needs to be lowered to about 100 mA or less, and in order to dim the dimming ratio to about 5%, the lamp current needs to be lowered to about 20 mA or less. However, as shown in FIG. 14, when the ambient temperature decreases, the lamp characteristics change greatly. Particularly, in the region where the dimming ratio is 25% to 5%, the lamp voltage changes greatly at low temperatures, so that the fluorescent lamp operates normally. It becomes difficult to maintain. As a result, the ballast cannot supply a voltage for maintaining the lamp on, the output fluctuates rapidly, and the dimming characteristics of the lamp become discontinuous (hereinafter referred to as a jump phenomenon), A phenomenon that the lamp is completely extinguished (hereinafter referred to as the extinction phenomenon) occurs.

  In particular, when such a jump phenomenon or disappearance phenomenon occurs at low temperatures, the feedback control operates to increase the output, but the output increases rapidly again, so normal feedback operation cannot be performed. As shown in FIG. 15, a vibration phenomenon in which the output of the lamp fluctuates periodically occurs.

  FIG. 15 shows a waveform when an FHF32 fluorescent lamp manufactured by Matsushita Electric Industrial Co., Ltd. is dimmed and lit at a dimming ratio of about 20% in an environment with an ambient temperature of 0 ° C. The oscillation phenomenon of the output by such feedback control has a time constant determined by the product of the resistance value of the resistor R2 and the capacitance value of the capacitor C4 shown in FIG. 13 when the response speed of the feedback control circuit is fast. When the operation period of the inverter circuit is close, the vibration amplitude of the discharge lamp output tends to be relatively stable as shown in FIG.

  However, when the discharge lamp is turned on near the rated power, the amplitude of the detection voltage generated in the resistor R1 increases, an excessive signal is input to the operational amplifier OP1, and the amplification factor of the operational amplifier OP1 near the operating frequency of the inverter circuit is relatively high. The output voltage of the operational amplifier OP1 oscillates abnormally due to its large size, delay in the response of the operational amplifier OP1, lack of output current supply capability, etc., and there is a problem that normal feedback control cannot be performed. For this reason, there is a limit to increasing the response speed of the feedback control circuit in order to sufficiently stabilize the output during dimming.

  Further, as shown in FIGS. 15B and 15C, when the response speed of the feedback control circuit is relatively slow, abnormal oscillation of the operational amplifier OP1 does not occur near the rated power, but the discharge lamp output is dimmed. The periodic vibration amplitude of increases. At this time, the cycle and amplitude at which the output fluctuates depends on the response speed of the feedback control circuit and the transient response speed of the inverter circuit and discharge lamp, so the output fluctuation cycle and amplitude vary slightly due to the influence of disturbance factors. However, there is a drawback that flickering occurs at low temperatures.

  As another conventional example for preventing the discharge lamp jump phenomenon and the extinction phenomenon particularly at low temperatures, there is a technique disclosed in JP-A-6-76979. This is a technique in which a pulsed voltage is periodically applied to the discharge lamp to avoid unstable phenomena such as flickering and to maintain a stable discharge up to a low luminous flux.

Specifically, a high-frequency power supply circuit that supplies high-frequency power to the discharge lamp is provided, and the electric power supplied to the discharge lamp is varied using a dimming control unit according to the input dimming signal, thereby adjusting the discharge lamp. Light is applied and the output state of the power supplied to the discharge lamp is periodically switched using the lamp operation point switching control unit, whereby a pulsed voltage waveform is periodically applied to the discharge lamp to stabilize the discharge lamp. It is made to light up. However, since this conventional example does not have an output feedback control function, there is a problem that the characteristics of the discharge lamp change due to variations in the characteristics of the discharge lamp or changes in the ambient temperature, resulting in large fluctuations in output.
JP-A-6-302393 JP-A-6-311753 JP-A-6-76979

  The present invention has been invented in view of the above-described background art, and its problem is that, in a discharge lamp lighting device that performs dimming of a discharge lamp, fluctuations in the discharge lamp output even when the ambient temperature decreases. It is to suppress light and to perform stable dimming without causing problems such as flickering and disappearance.

  In the present invention, in order to solve the above problem, as shown in FIG. 1, a rectifier DB that rectifies an input voltage from an AC power supply AC, and a DC power supply that smoothes a pulsating voltage output from the rectifier. Part (step-up chopper circuit 6 and smoothing capacitor C1) and at least one switching element Q2, Q3, and an inverter part 4 for inputting the DC smoothed voltage Vdc output from the DC power supply part and converting it into a high-frequency voltage; A resonance load unit 5 that includes at least one inductor L2 and a capacitor C2, inputs a high-frequency voltage output from the inverter unit 4 and lights the discharge lamp DL by a resonance action, and a switching element of the inverter unit 4 Inverter control means A that generates on / off control signals for Q2 and Q3 and outputs drive signals, and dimming input from the outside And a dimming control unit that varies the on / off control signal generated by the inverter control means A according to the signal, the dimming control unit detects an electrical output of the discharge lamp DL Output detection means (resistor R1), a dimming signal setting means (dimming signal generation circuit 9) for setting a dimming command value according to the input dimming signal, and detection output from the output detection means A feedback control means B for comparing the signal and the dimming command value output from the dimming signal setting means, and varying the on / off signal generated by the inverter control means A according to the calculation result, A pulse voltage superimposing means C for applying a pulsed high voltage to the discharge lamp DL at a predetermined cycle is provided.

  Thus, according to the first aspect of the present invention, the discharge lamp lighting that detects the lighting state of the discharge lamp and performs feedback control so that the discharge lamp has a predetermined output in accordance with the input dimming signal. In the apparatus, by providing a pulse voltage superimposing means for periodically applying a pulsed voltage to the discharge lamp, instability phenomenon such as flickering and extinction at a low temperature is improved.

  According to the invention of claim 1, since both the feedback control means for controlling the output of the discharge lamp substantially constant and the pulse voltage superimposing means for preventing flickering and extinction especially at low temperatures are provided, the ambient temperature is lowered. It is possible to suppress the accompanying decrease in the discharge lamp output and to prevent the occurrence of flickering or extinction.

  Further, according to the inventions of claims 2 to 3, flickering at the time of a jump phenomenon, feedback control responsiveness, etc. are obtained by synchronizing the fluctuation cycle of feedback control that occurs particularly at low temperatures and the application cycle of the pulse voltage. Flicker due to mismatch with the pulse period can be improved.

  Further, according to the inventions of claims 4 to 5, since more preferable conditions of the application period, pulse height, and pulse width of the pulse voltage applied to the discharge lamp are provided, more stable light control can be performed.

(Embodiment 1)
Hereinafter, a discharge lamp lighting device according to a first embodiment of the present invention will be described with reference to FIG. 1, FIG. 2, and FIG. FIG. 1 shows a circuit diagram of the present embodiment, and FIGS. 2 and 3 show details of the control unit 7.

  First, the configuration of the discharge lamp lighting device 1 will be described with reference to FIG. The discharge lamp lighting device 1 of the present embodiment includes an AC-DC converter 3 including a diode bridge DB, a step-up chopper circuit 6 and an electrolytic capacitor C1, which are connected to a commercial power supply AC, a half-bridge inverter 4, and a resonance circuit 5. A control unit 7, a fixed resistor R1, a discharge lamp DL (hereinafter referred to as a discharge lamp DL), and a dimming signal generation circuit 9.

  The lighting circuit 2 includes an AC-DC converter 3, a half bridge inverter 4, and a resonance circuit 5. The control unit 7 also includes a chopper control circuit 8 that controls the switching element Q1 of the boost chopper circuit 6, an A circuit that is a drive frequency control circuit for the switching elements Q2 and Q3, a B circuit that is feedback control means, and a pulse voltage. A C circuit as superimposing means is provided.

  The commercial power source AC is a commercial AC power source, and its voltage is, for example, 100 V or 200 V, and its frequency is 50 Hz or 60 Hz.

  The AC-DC converter 3 includes a diode bridge DB that full-wave rectifies the power supply voltage of the commercial power supply AC, a boost chopper circuit 6 that boosts the output of the diode bridge DB, and an electrolytic capacitor C1 that smoothes the output voltage. However, the step-up chopper circuit 6 may be a step-down chopper circuit, a step-up / step-down chopper circuit, or a circuit in which a step-up chopper circuit and a step-down chopper circuit are connected in series. In short, any circuit configuration may be used as long as it converts a certain AC voltage into another DC voltage.

  The half-bridge inverter 4 has a series circuit of switching elements Q2 and Q3 connected between output terminals of the AC-DC converter 3, and a control unit 7 for supplying switching signals of the switching elements Q2 and Q3 is connected to the half-bridge inverter 4. The resonance circuit 5 is connected from the connection point of the switching elements Q2 and Q3 of the half-bridge inverter 4, and the current flowing through the half-bridge inverter 4 is detected by converting the current flowing through the half-bridge inverter 4 to the low potential (source) side of the switching element Q3. A fixed resistor R1 for input to the control unit 7 is connected.

  That is, the DC voltage Vdc obtained by the AC-DC converter 3 is converted into a high-frequency rectangular wave AC voltage by the high-frequency switching operation of the half-bridge inverter 4 and output to the connection point of the switching elements Q2 and Q3 of the half-bridge inverter 4. Is done. When this rectangular wave AC voltage is input to the resonance circuit 5, a substantially sinusoidal voltage is generated due to a resonance action and applied to both ends of the discharge lamp DL, and the discharge lamp DL is lit. At this time, a voltage obtained by converting the current flowing through the switching element Q3 by the fixed resistor R1 is fed back to the control unit 7.

  The power for turning on the discharge lamp DL is determined by generating a DC voltage Vref that is variable by the dimming signal generation circuit 9 in accordance with an external dimming signal, and this DC voltage Vref is input to the control unit 7. Has been.

Next, as shown in FIGS. 1, 2, and 3, the control unit 7 includes an A circuit, a B circuit, and a C circuit.
The A circuit is a drive frequency control circuit for the switching elements Q2 and Q3, and the B circuit is a feedback control circuit. As shown in FIG. 2, the output detection signal detected by the fixed resistor R1 is connected to the operational amplifier via the input resistor R2. In addition to being input to the inverting input terminal of OP1, the dimming signal Vref generated by the dimming signal generation circuit 9 is input to the non-inverting input terminal of the operational amplifier OP1. Further, a feedback resistor R4 and a capacitor C4 connected in parallel with each other are connected between the output terminal and the inverting input terminal of the operational amplifier OP1, so that the voltage levels of the detection signal and the dimming signal Vref are always substantially the same. Control (feedback control) is performed to control the drive frequency control circuit A and adjust the drive frequency of the switching elements Q1, Q2.

  The C circuit includes a circuit that outputs a control signal for supplying a pulse signal to the A circuit. By supplying a periodic pulse-like signal voltage Vpc from the C circuit to the A circuit, the drive frequency of the inverter circuit 4 is periodically varied, and thereby a high frequency voltage (lamp voltage) applied to the discharge lamp DL. ) Is periodically changed to apply a pulsed high voltage (pulse voltage) to both ends of the discharge lamp DL.

  A specific configuration example of the C circuit is shown in FIG. As shown in FIG. 3, the C circuit has a first buffer B1 made of an operational amplifier connected to the A circuit and a cathode connected to the input terminal of the first buffer B1 (the non-inverting input terminal of the operational amplifier). A second buffer B2 made of an operational amplifier and having an output terminal connected to the anode of one diode D2, and a third buffer having an output terminal connected to the anode of the other diode D3. Buffer B3.

  A DC voltage signal Vref as shown in FIG. 4A is input to the input terminal of the second buffer B2, and a pulse having a cycle T1 and a pulse as shown in FIG. 4B is input to the input terminal of the third buffer B3. A pulse signal Vpl of width t1 is inputted, and a signal (hereinafter referred to as “pulse voltage command signal”) Vpc obtained by synthesizing these two kinds of signals by diodes D2 and D3 as indicated by a solid line in FIG. Is supplied to the A circuit via the first buffer B1. Thus, by varying the amplitude of the pulse voltage command signal Vpc in accordance with the input dimming signal, it is possible to control the pulse voltage amplitude in accordance with the dimming level.

  The A circuit, which is a drive frequency control circuit, feedback-controls the drive frequency of the switching elements Q2, Q3 to a value corresponding to the dimming ratio according to the output voltage level input from the B circuit, and the pulse voltage input from the C circuit. The drive frequency is periodically changed to a low value by a frequency corresponding to the pulse voltage command signal amplitude of the command signal Vpc. As a result, as shown in FIG. 9, when the drive frequency is periodically changed from fb to fa, the lamp voltage Vla applied to the discharge lamp DL from the inverter circuit 4 through the resonance circuit 5 increases. A pulse voltage is applied to the discharge lamp DL.

  Here, the output voltage waveform to the discharge lamp DL according to this configuration is shown in FIG. FIG. 5 shows an example in which a pulse voltage is applied to the lamp voltage Vla at a period T1 of about 1.6 msec, and the envelope of the lamp voltage at a high frequency (several tens of kHz) increases in a pulse manner at the period of T1. By doing so, it can be seen that a pulse voltage is substantially applied. The period of applying this pulse voltage is usually about 10 msec or less, so that fluctuations in the output due to the application of the pulse voltage can be prevented from flickering.

  In the present embodiment, the feedback control for adjusting the drive frequency of the inverter circuit 4 is performed by the B circuit so that the voltage levels of the output detection signal and the dimming signal are always equal as described above. There is an advantage that the output of the discharge lamp DL can be suppressed from being lowered, and the occurrence of problems such as a jump phenomenon and extinction at a low temperature can be suppressed by periodically applying a pulse voltage.

(Embodiment 2)
Hereinafter, a second embodiment of the present invention will be described with reference to FIGS. The circuit configuration is the same as in FIG. In this embodiment, in particular, by optimizing the application period of the pulse voltage, it is possible to prevent flickering due to mismatch between the feedback control and the pulse voltage application condition, and to obtain more stable dimming performance. it can.

  FIG. 6 shows the lamp voltage when the FHF32 fluorescent lamp manufactured by Matsushita Electric Industrial Co., Ltd. is dimmed and lit at a dimming ratio of about 20% in an environment of an ambient temperature of 0 ° C. with only feedback control (no pulse voltage superposition). It is a waveform.

  FIG. 7 shows the result of visual confirmation of the ramp voltage waveform, the output voltage waveform of the operational amplifier OP1, and the flicker occurrence state when the pulse voltage application period T1 is changed. (Here, as a typical example, measurement results of pulse voltage application periods of 3.2 msec, 2.5 msec, and 1.6 msec are shown.)

  As shown in FIG. 6, in the state of only the feedback control (no superposition of the pulse voltage), as explained in the conventional example, the feedback control vibrates due to the occurrence of the jump phenomenon, and has a period of about 3.2 msec (hereinafter, The output oscillates periodically and flickers.

  In the present embodiment, as shown in FIG. 7, no flicker occurred when the pulse application period was 3.2 msec or 1.6 msec, whereas flicker occurred when the pulse application period was 2.5 msec. This is because when the pulse application cycle T1 is 3.2 msec and 1.6 msec, the pulse application cycle is substantially synchronized with the oscillation cycle of the lamp voltage only by feedback control (T2 = about 3.2 msec), and the output voltage of the operational amplifier It is because it is also stable. That is, when the pulse application cycle T1 is 3.2 msec, the pulse voltage is applied once for one cycle of the ramp voltage oscillation only by feedback control, and when 1.6 msec, the pulse voltage is applied twice for one cycle of the ramp voltage oscillation. There is no flickering, and the output voltage of the operational amplifier is stable.

  However, when the pulse voltage application period T1 is 2.5 msec, the output voltage of the operational amplifier becomes unstable because the pulse voltage application period T1 is not synchronized with the oscillation period T2 of the lamp voltage by only feedback control. It can be seen that flickering occurs. In other words, the feedback control becomes unstable due to the mismatch between the feedback control response and the pulse voltage application cycle, and flickering occurs when the pulse is applied.

  From the above, by synchronizing the pulse voltage application period T1 with the lamp voltage oscillation period T2 by only feedback control, it is possible to suppress the occurrence of flickering due to feedback control response and pulse voltage application period mismatch. I understand.

  According to the present embodiment, the pulse voltage application period T1 is set to approximately 1 / N times (N is an integer of 1 or more) with respect to the feedback vibration period T2, thereby suppressing the occurrence of flicker even at low temperatures. Therefore, stable dimming of the discharge lamp can be performed. Even when the pulse voltage application period T1 is approximately N times (N is an integer equal to or greater than 1) with respect to the feedback vibration period T2, the feedback control response and the pulse voltage application period are based on the same principle. Therefore, the occurrence of flickering can be suppressed even at low temperatures, and stable dimming of the discharge lamp can be performed.

(Embodiment 3)
Hereinafter, a third embodiment of the present invention will be described with reference to FIG. In this embodiment, flickering due to mismatch between the feedback control and the pulse voltage application condition is achieved by optimizing the pulse voltage application conditions (application period, pulse height, pulse width, etc.). And more stable light control performance can be obtained.

  FIG. 8 shows the duty ratio of the pulse application interval t1 with respect to the pulse application period T1 in a state where a FHF32 fluorescent lamp manufactured by Matsushita Electric Industrial Co., Ltd. is lit with a dimming ratio of about 20% in an environment of an ambient temperature of 0 ° C. Is a result of observing the occurrence of flicker when the pulse application peak voltage value Vo-p is changed to about 4.0 times the lamp voltage effective value (Vrms).

  Here, FIG. 8A is a graph showing the results when the duty ratio of the pulse application interval t1 to the pulse application period T1 is 3%. FIG. 8B is a graph showing the results when the duty ratio of the pulse application section t1 with respect to the pulse application period T1 is 5%. FIG. 8C is a graph showing the results when the duty ratio of the pulse application interval t1 with respect to the pulse application period T1 is 10%. FIG. 8D is a graph showing the results when the duty ratio of the pulse application period t1 with respect to the pulse application period T1 is changed from 15% to 50%. In addition, since the substantially same result was obtained from duty ratio 15% to 50%, a result is shown in one graph shown in FIG.8 (d).

  In the graphs of FIGS. 8A to 8D, the stable region indicates the lamp voltage waveform, the operational amplifier output voltage waveform, and the case where all the flicker visual evaluations are stable in the “OK” region. The region where the operational amplifier output voltage waveform becomes unstable and flicker is confirmed is shown in gray.

  According to FIG. 8, as described in the second embodiment, the pulse application period is 1 / N times or N times (N times) the lamp voltage oscillation period (T2 = about 3.2 msec) only by feedback control. It can be seen that dimming can be performed stably without flickering even at a relatively low pulse voltage in the vicinity of 1).

  However, it can be seen that the larger the duty ratio and the higher the pulse application peak voltage, the wider the pulse application cycle region in which light can be stably adjusted without flickering.

  In particular, as shown in FIG. 8D, when the duty ratio of the pulse application period t1 with respect to the pulse application period T1 is about 15% or more, the pulse application peak voltage value (Vo-p) becomes the lamp voltage effective value (Vrms). ) In a region more than twice as large as possible, stable dimming without flickering is possible in a relatively wide pulse application period range, and the pulse application period T1 is substantially reduced with respect to the lamp voltage oscillation period T2 by only feedback control. It can be seen that there is no need to synchronize.

  More specifically, based on the result shown in FIG. 8D, only the feedback control is performed in the region where the pulse application peak voltage value (Vo-p) is about 2 to 3 times the lamp voltage effective value (Vrms). The pulse application period (T1) is T2 ≦ T1 ≦ N × T2 (N is an integer of 1 or more, N × T2 ≦ about 10 msec) or 1/2 × T2 ≦ with respect to the lamp voltage oscillation period (T2). Stable dimming operation was obtained within a range satisfying the condition of T1 ≦ 3/4 × T2.

  In addition, in a region where the pulse application peak voltage value (Vo-p) is about three times or more of the lamp voltage effective value (Vrms), a stable dimming operation was obtained regardless of the pulse application period T1. However, considering the electrical stress on the circuit components, it is preferable that the pulse application peak voltage value (Vo-p) is low, and the variation of the components of the lighting device, the variation of the discharge lamp, the variation of the pulse application period, etc. In view of the above, it is needless to say that it is more preferable to synchronize the pulse application period T1 with the oscillation period T2 of the lamp voltage by only feedback control as described in the second embodiment.

  According to the present embodiment, the duty ratio of the pulse application period t1 with respect to the pulse application period T1 is set to about 15% or more, and the pulse application peak voltage value (Vo-p) is about twice or more the lamp voltage effective value (Vrms) 3 The pulse application period T1 is T2 ≦ T1 ≦ N × T2 (N is an integer equal to or greater than 1) or 1/2 × T2 ≦ T1 ≦ 3 / The pulse condition satisfying the condition of 4 × T2 or the duty ratio of the pulse application section t1 with respect to the pulse application cycle T1 is set to about 15% or more, and the pulse application peak voltage value (Vo-p) is the lamp voltage effective value (Vrms). By setting the pulse condition to be about 3 times or more, it is less affected by variations in lighting device components, discharge lamp variations, and pulse application cycle. Dimming boss had discharge lamp becomes possible to supply the lamp lighting device release performed.

(Embodiment 4)
Hereinafter, a fourth embodiment of the present invention will be described with reference to FIG. The oscillation of the lamp voltage generated by the feedback control has its oscillation cycle depending on the frequency response characteristic of the feedback control circuit determined by the operational amplifier OP1 and its peripheral components (capacitor C4, resistors R2, R4) constituting the feedback control means B in FIG. fluctuate.

  Here, by setting the frequency response characteristics of the feedback control circuit so that the lamp voltage oscillation period by the feedback control is about 10 msec or less, the vibration of the light output generated by the lamp voltage oscillation is less noticeable to the eyes. , Flicker can be suppressed. FIG. 10 shows the frequency response characteristics of the feedback control circuit when R2 = 10 kΩ, R4 = 1000 kΩ, and C4 = 18 nF, for example. As shown in FIG. 10, by increasing the feedback gain in the low frequency region, the oscillation cycle of the lamp voltage can be shortened and flickering can be suppressed.

  More specifically, as shown in FIG. 10, by configuring the feedback control means so that the frequency characteristic of the feedback gain is 0 (zero) decibels or higher in the frequency band of 1 kHz or lower, the oscillation cycle of the lamp voltage is achieved. Is about 10 msec or less, and the light output fluctuation can be substantially prevented from being perceived as flicker. At this time, by applying the pulse voltage application cycle to the discharge lamp below the oscillation cycle of the lamp voltage by feedback, the feedback gain has a relatively low frequency band with respect to the applied frequency of the pulse voltage. Therefore, the degree of influence on the feedback control by applying the pulse voltage can be reduced.

  In the present embodiment, the feedback control circuit shown in FIG. 2 has been described. However, the circuit configuration is not limited to this, and other configurations may be used.

  According to this embodiment, the flicker generated by the oscillation of the lamp voltage generated by the feedback control can be made substantially unnoticeable. Moreover, the influence on the feedback control by applying the pulse voltage can be reduced, and the occurrence of flickering by applying the pulse voltage can be suppressed.

(Embodiment 5)
FIG. 11 shows an example of a straight tube type lighting fixture 20, and straight tube lamps mainly used for facilities and stores are used as the discharge lamps Lpa and Lpb. That is, the discharge lamp lighting device 21 according to any of the first to fourth embodiments described above, the main body 24 to which the discharge lamp lighting device 21 is mounted, and the discharge lamps Lpa and Lpb to which power is supplied from the discharge lamp lighting device 21. The lighting fixture 20 is comprised from these. The main body 24 is a so-called Fuji-type lighting fixture for two lights. Reference numeral 22 denotes a socket to which the discharge lamp Lpa is mounted, and reference numeral 23 denotes a white reflector disposed on the side facing the discharge lamps Lpa and Lpb.

(Embodiment 6)
FIG. 12 shows an example of a lighting system, and the lighting system is composed of the plurality of lighting fixtures 20 described above and a control device S that controls these lighting fixtures 20. Each lighting fixture 20 is provided with a human body detection sensor (not shown), and the control device S collectively controls, for example, the human body detection sensors and light fluxes of twelve lighting fixtures A to L by a program.

  As a feature of the control device S, a discharge lamp is turned on when a person is detected by a human body sensor, and a function of dimming or turning off when a person is absent, an input of a discharge lamp mounting state, and turning on / off an arbitrary lighting fixture It has a program control function capable of setting conditions, and can realize an extremely efficient and energy saving lighting system according to the installation environment.

It is a circuit diagram which shows the whole structure of Embodiment 1 of this invention. It is a circuit diagram which shows the principal part structure of Embodiment 1 of this invention. It is a circuit diagram which shows the principal part structure of Embodiment 1 of this invention. It is a wave form diagram for operation | movement description of Embodiment 1 of this invention. It is a wave form diagram which shows the lamp voltage of Embodiment 1 of this invention. It is a wave form diagram which shows the lamp voltage of Embodiment 2 of this invention. It is a wave form diagram for description of operation | movement of Embodiment 2 of this invention. It is explanatory drawing which shows the preferable operation | movement range of Embodiment 3 of this invention. It is operation | movement explanatory drawing of Embodiment 1 of this invention. It is operation | movement explanatory drawing of Embodiment 4 of this invention. It is a front view of the lighting fixture which concerns on Embodiment 5 of this invention. It is a whole block diagram of the illumination system which concerns on Embodiment 6 of this invention. It is a circuit diagram which shows the structure of a prior art example. It is explanatory drawing which shows the subject of a prior art example. It is a wave form diagram which shows the lamp voltage of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Discharge lamp lighting device 2 Lighting circuit 3 AC-DC converter 4 Inverter circuit 5 Resonance circuit 7 Control part 9 Dimming signal generation circuit DL Discharge lamp

Claims (9)

A rectifier that rectifies the input voltage from the AC power supply;
A DC power supply unit that smoothes the pulsating voltage output from the rectifier;
An inverter unit configured by at least one switching element, for converting a DC smoothed voltage output from the DC power source unit into a high frequency voltage;
A resonance load unit configured to include at least one inductor and a capacitor, input a high-frequency voltage output from the inverter unit, and light a discharge lamp by a resonance action;
An inverter control unit that generates an on / off control signal for the switching element of the inverter unit and outputs a drive signal;
In a discharge lamp lighting device comprising: a dimming control unit that varies an on / off control signal generated by the inverter control unit according to a dimming signal input from the outside,
The dimming controller is
Output detection means for detecting the electrical output of the discharge lamp;
A dimming signal setting means for setting a dimming command value according to the input dimming signal;
A feedback that compares the detection signal output from the output detection means with the dimming command value output from the dimming signal setting means, and varies the on / off signal generated by the inverter control unit according to the calculation result Having control means,
A discharge lamp lighting device comprising pulse voltage superimposing means for applying a pulsed high voltage to the discharge lamp at a predetermined cycle. The pulse high voltage application period T1 set by the pulse voltage superimposing means is T1≈T2 × N or T1≈T2 / N with respect to the vibration period T2 of the voltage envelope of the discharge lamp generated in the dimming region of the discharge lamp. 2. The discharge lamp lighting device according to claim 1, wherein N is an integer of 1 or more. The pulse period high voltage application period T1 is T1≈T2 / N (N is an integer from 1 to 3) with respect to the oscillation period T2 of the discharge lamp voltage envelope generated in the dimming region of the discharge lamp, 3. The discharge lamp lighting device according to claim 2, wherein the ratio of the pulse-shaped high voltage application time width t1 to the pulse-shaped high voltage application period T1 is 5% ≦ t1 / T1 <15%. The ratio of the pulse high voltage application time width t1 to the pulse high voltage application period T1 set by the pulse voltage superimposing means is t1 / T1 ≧ 15%, and the peak value of the pulse high voltage is the discharge lamp. With respect to the oscillation period T2 of the voltage envelope of the discharge lamp generated in the dimming region of the discharge lamp, the application period T1 of the pulsed high voltage is T2 ≦ T1 ≦. 2. The discharge lamp lighting device according to claim 1, wherein N × T2 (N is an integer of 1 or more) or 1/2 × T2 ≦ T1 ≦ 3/4 × T2. The ratio of the pulse high voltage application time width t1 to the pulse high voltage application period T1 set by the pulse voltage superimposing means is t1 / T1 ≧ 15%, and the peak value of the pulse high voltage is the discharge lamp. The discharge lamp lighting device according to claim 1, wherein the voltage effective value is three times or more. The feedback control means includes an operational amplifier for performing a feedback calculation, and is configured so that an amplification factor of the operational amplifier is 0 decibel or higher in a frequency band of 1 kHz or lower. The discharge lamp lighting device according to any one of the above. The discharge lamp lighting device according to claim 6, wherein the application period T1 of the pulsed high voltage is T1≤T2 with respect to the vibration period T2 of the voltage envelope. An illumination comprising: the discharge lamp lighting device according to any one of claims 1 to 7, a main body on which the discharge lamp lighting device is mounted, and a discharge lamp to which electric power is supplied from the discharge lamp lighting device. apparatus. An illumination system comprising the illumination device according to claim 8 and a control device that provides a dimming signal to the illumination device.

Images