JP5472564B2 - Discharge lamp lighting device - Google Patents

Description

  The present invention relates to a discharge lamp lighting device for lighting a discharge lamp.

  Conventionally, in a discharge lamp lighting device, for example, a half-bridge type inverter circuit is used, and an LC resonance circuit including an inductor and a capacitor is connected between outputs of the inverter circuit. Is started and lit.

  Also, when it has the function of dimming the discharge lamp, it detects the discharge voltage of the discharge lamp and the current output from the inverter circuit in order to steadily dim the discharge lamp, especially during deep dimming. The inverter circuit is feedback-controlled using the detected voltage and output current.

  When such a discharge lamp lighting device is used in a region where the operating frequency is higher than the resonant frequency of the resonant circuit when there is no load, when starting the discharge lamp, the operating frequency is temporarily reduced and the inverter circuit is After the discharge lamp is turned on by increasing the output high-frequency voltage to a predetermined starting voltage, the operation frequency is controlled to return to the predetermined frequency.

In this control, the threshold voltage preset in the vicinity of the starting voltage is compared with the discharge voltage of the discharge lamp detected during the starting operation, and the control means determines that the discharge lamp is lit when the discharge voltage exceeds the threshold voltage. Judgment is made (see, for example, Patent Document 1).
Japanese Patent Laying-Open No. 2006-210267 (page 4-6, FIG. 1)

  However, the above-described discharge lamp lighting device requires a lighting detection means for detecting the lighting of the discharge lamp by comparing the discharge voltage of the discharge lamp with the threshold voltage, and has a problem that the configuration becomes complicated. ing.

  In addition, when comparing the discharge voltage of the discharge lamp with the threshold voltage, detection is not always possible at the moment when the discharge voltage exceeds the threshold voltage, so the lamp current or lamp power increases momentarily, and the discharge lamp is There is also a problem that it lights up brightly for a moment.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a discharge lamp lighting device capable of preventing a discharge lamp from being lit brightly at the time of starting without complicating the configuration.

The discharge lamp lighting device according to claim 1 includes an inverter circuit that converts a DC voltage into a high-frequency voltage and outputs it by an operation of the switching element; an inductor and a capacitor connected in series between outputs of the inverter circuit; a resonant circuit which resonates in response to the high frequency voltage; of the discharge lamp a preheating period after the end of this discharge lamp; connected across the capacitor of the resonance circuit, a discharge lamp and for lighting by resonance of the resonant circuit Current detecting means for detecting a current obtained by removing a leakage current flowing outside the discharge lamp by a capacitive component without flowing into the discharge lamp during the starting period of the discharge lamp from the current flowing during the starting period; and the current detecting means Feedback control of the switching element of the inverter circuit based on the current detected in step 1, and during preheating, the discharge lamp Heat and current and detecting a current except for the leakage current by the current detecting means supplies to reduce the operating frequency at the time after the completion of at least the preheating operation starting with higher frequency voltage than when preheating the discharge lamp discharge lamp And a control means for controlling the inverter circuit by the feedback control at every period when the current detection means detects the current so as to obtain a desired current value.

  Examples of the discharge lamp include, but are not limited to, a hot cathode fluorescent lamp and a high pressure discharge lamp.

  The inverter circuit may be either a half bridge type or a full bridge type as long as it can convert a DC voltage into a high frequency voltage by an operation of a switching element such as a field effect transistor.

  The current that substantially flows in the discharge lamp refers to a current that flows in the discharge lamp, excluding, for example, a leakage current that flows through a capacitive component.

  The detection of the current that substantially flows through the discharge lamp by the current detection means means that the starting voltage of the discharge lamp has been reached, so that when the starting voltage of the discharge lamp is reached, the current of the discharge lamp is instantaneously desired. With this current value, the discharge lamp can be turned on and started to such an extent that a human eye does not feel a flash even from a low dimming rate.

Then, by performing feedback control of the switching element of the inverter circuit every period by the current detected by the current detection means, the inverter circuit is accurately feedback controlled by the discharge current of the discharge lamp, and at least after the preheating operation is completed by the control means. The operating frequency is lowered and a relatively high frequency voltage is supplied to the discharge lamp during preheating, and the current detection means causes the current flowing in the discharge lamp after the preheating period to end during the starting period. In the inverter circuit, the current flowing through the discharge lamp, excluding the leakage current flowing outside the discharge lamp due to the capacitive component without flowing into the discharge lamp, is detected so that the current of the discharge lamp becomes a desired current value. By performing feedback control every period when the current detection means detects the current, the responsiveness of the feedback control is improved and released. The discharge lamp at startup without providing a structure for detecting the lighting of the lamp separately it is possible to prevent the brightly lit momentarily.

  The discharge lamp lighting device according to claim 2 is the discharge lamp lighting device according to claim 1, wherein the feedback control of the switching element of the inverter circuit by the control means is performed at least after the preheating operation is completed. It is performed in a predetermined short period in the process until lighting, and gradually increases the target value of the current after the end of the preheating operation, thereby gradually increasing the light quantity of the discharge lamp to obtain a desired lighting state.

  The feedback control response is achieved by performing feedback control of the switching element of the inverter circuit by the control means at a predetermined short period at least in the process from the end of the preheating operation to the desired lighting of the discharge lamp including the starting time. In addition, the target value of the current after the preheating operation is gradually increased to gradually increase the light quantity of the discharge lamp to obtain a desired lighting state. It becomes possible to start lighting the discharge lamp without lighting.

The discharge lamp lighting device 請 Motomeko 3 wherein, in the discharge lamp lighting device according to claim 1 or 2, wherein the control means is to start the discharge lamp when the discharge lamp is mounted.

  Then, by starting the discharge lamp at the time of mounting, it becomes possible to gradually start lighting the discharge lamp even when the discharge lamp is mounted.

According to a fourth aspect of the present invention, there is provided the discharge lamp lighting device according to any one of the first to third aspects, wherein the control means is configured such that the dimming signal is input by an external operation when the discharge lamp is turned off. Is to start.

  The external operation refers to an operation of a dimming operation means such as a dimming remote controller.

  Then, by starting the discharge lamp when a dimming signal is input by an external operation while the discharge lamp is turned off, it becomes possible to gradually start the discharge lamp in response to the external operation.

The discharge lamp lighting device according to claim 5 is the discharge lamp lighting device according to claim 4, wherein the control means changes the followability of the light amount of the discharge lamp in accordance with a change amount of the dimming signal input by an external operation. It is something to be made.

  Then, by changing the followability of the light quantity of the discharge lamp in accordance with the amount of change in the dimming signal input by an external operation, dimming with less discomfort to the human eye becomes possible.

The discharge lamp lighting device according to claim 6 is the discharge lamp lighting device according to claim 5, wherein the control means changes the change amount of the dimming signal input by an external operation when the change amount is less than a predetermined value. If the amount of change in the dimming signal input by an external operation is equal to or greater than the predetermined value, the target value of the discharge lamp current is set at the predetermined upper limit value. It is made to follow to the value.

  If the change amount of the dimming signal input by the external operation is less than the predetermined value, the current of the discharge lamp is made to follow the target value with a value corresponding to the change amount, and the adjustment input by the external operation is performed. When the amount of change in the optical signal is greater than or equal to a predetermined value, set the discharge lamp's current to the target value with a predetermined upper limit so that the light quantity of the discharge lamp does not follow too late or too early. It becomes possible.

According to the discharge lamp lighting device of the first aspect, the switching element of the inverter circuit is feedback-controlled every period by the current detected by the current detection means in the peak phase of the discharge lamp voltage, so that the discharge lamp discharge current The inverter circuit is accurately feedback controlled, and the control means lowers the operating frequency at least after the preheating operation is completed, and supplies a relatively high frequency voltage to the discharge lamp at the time of preheating, and the current detection means preheats the discharge lamp. Current that substantially flows through the discharge lamp after the end of the period, excluding leakage current that flows outside the discharge lamp due to a capacitive component without flowing into the discharge lamp during the starting period from the current flowing during the starting period of the discharge lamp Is detected every time the current detection means detects the current so that the current of the discharge lamp becomes a desired current value. By back control, improved responsiveness of the feedback control, the discharge lamp lighting of the discharge lamp at startup without providing separately a structure for detecting can be prevented from brightly lit momentarily.

  According to the discharge lamp lighting device according to claim 2, in addition to the effect of the discharge lamp lighting device according to claim 1, feedback control of the switching element of the inverter circuit by the control means is performed at least after the preheating operation is started. In the process until the desired lighting of the discharge lamp including the discharge lamp, the responsiveness of the feedback control can be further improved by performing it in a predetermined short cycle, and the target value of the current after the preheating operation is gradually increased to increase the discharge lamp. By gradually increasing the amount of light to obtain a desired lighting state, it is possible to start lighting the discharge lamp without lighting brightly for a moment until the desired lighting state is reached.

According to the discharge lamp lighting apparatus 請 Motomeko 3 wherein, in addition to the effects of the discharge lamp lighting device according to claim 1 or 2, wherein the discharge lamp to be to start at the time of mounting, even when the discharge lamp is mounted this The discharge lamp can be gradually turned on.

According to the discharge lamp lighting device according to claim 4 , in addition to the effect of the discharge lamp lighting device according to any one of claims 1 to 3 , when a dimming signal is input by an external operation with the discharge lamp turned off. By starting the discharge lamp, the discharge lamp can be gradually turned on in response to an external operation.

According to the discharge lamp lighting device according to claim 5 , in addition to the effect of the discharge lamp lighting device according to claim 4 , the followability of the light amount of the discharge lamp according to the amount of change of the dimming signal input by an external operation. By changing, dimming can be performed with less discomfort to the human eye.

According to the discharge lamp lighting device according to claim 6 , in addition to the effect of the discharge lamp lighting device according to claim 5 , when the amount of change of the dimming signal input by an external operation is less than a predetermined value, If the current of the discharge lamp is made to follow the target value with a value corresponding to this amount of change, and the amount of change in the dimming signal input by an external operation is greater than or equal to a predetermined value, the current of the discharge lamp is at a predetermined upper limit value. Can be set so that the follow-up of the light quantity of the discharge lamp is not too late or too early.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a circuit diagram of a discharge lamp lighting device, FIG. 2 is a waveform diagram showing the relationship between the discharge voltage, discharge current, and leakage current of the discharge lamp lighting device, and FIG. FIG. 4 shows a detection method for detecting the peak phase, (a) is a waveform diagram of the discharge voltage and discharge current, (b) is a waveform diagram obtained by sampling the discharge voltage and discharge current, and FIG. 4 shows the detection method. ) Is a waveform diagram of the discharge voltage and discharge current, (b) is a waveform diagram obtained by sampling the discharge voltage and discharge current, and FIG. 5 shows the relationship among the discharge voltage, detected voltage, and leakage current component of the discharge lamp lighting device. FIG. 6 is a perspective view of a lighting fixture to which the discharge lamp lighting device is applied, and FIG. 7 shows the relationship between the frequency of the discharge lamp lighting device and the output voltage and discharge voltage on the secondary side of the resonance circuit. FIG. 8 shows the discharge voltage and output current of the discharge lamp lighting device. It is a waveform diagram showing the relationship with the light amount of the discharge lamp, (a) is a waveform diagram of the envelope of the discharge voltage, (b) is a waveform diagram of the envelope of the output current, (c) is an envelope of the light amount of the discharge lamp It is a wave form diagram of a line.

  As shown in FIG. 1, in the discharge lamp lighting device 10, the input terminal of a full-wave rectifying element REC that rectifies the commercial power supply voltage is connected to the commercial power source e, and the direct current rectified to the output terminal of the full-wave rectifying element REC. A booster circuit 11 that boosts the voltage is connected. A smoothing capacitor C1 is connected between the output terminals of the booster circuit 11, and an inverter circuit 12 for converting a DC voltage into a high-frequency voltage and outputting it is connected. This inverter circuit 12 is a half-bridge type inverter and has field effect transistors Q1 and Q2 as two switching elements connected in series. A DC cut capacitor (not shown) and a resonance circuit 13 having a resonance inductance L as an inductor and a resonance capacitor C2 as a capacitor are connected to both ends of the field effect transistor Q2. A discharge lamp FL such as a hot cathode fluorescent lamp is connected in parallel with the resonant capacitor C2. The heating means for heating the filament of the discharge lamp FL is omitted in the drawing.

  A control circuit 16 is connected to the gates of the field effect transistors Q1 and Q2 as control means for controlling the on / off operation of the field effect transistors Q1 and Q2.

  Further, a voltage dividing circuit 19 composed of a pair of resistors R1 and R2 is connected to both ends of the resonance capacitor C2, and the voltage detecting means 20 for detecting the voltage of the discharge lamp FL is configured by the voltage dividing circuit 19.

  Furthermore, a series circuit of a reverse blocking diode D1 and a resistor R3 is connected between one filament of the discharge lamp FL and one end of the resonant capacitor C2 that is grounded, and the anode side of the diode D1 and the resistor R3 The diode D2 is connected to the ground side, and the substantial current flowing through the discharge lamp FL at the connection point 23 between the diode D1 and the resistor R3, that is, the leakage current flowing into the capacitance component, etc. is excluded from the discharge lamp FL. Current detecting means 24 for detecting the current flowing in the current (hereinafter referred to as output current) is configured.

  These voltage detection means 20 and current detection means 24 are connected to a detection circuit 27. The detection circuit 27 has a function of a peak phase detection unit that detects a peak phase of the voltage detected by the voltage detection unit 20, and a phase of the voltage detected by the voltage detection unit 20 with respect to the phase of the discharge voltage of the discharge lamp FL. It has a function of a correction means for correcting the delay. Note that the functions of the peak phase detecting means and the correcting means may be provided in the control circuit 16. Here, the peak phase of the discharge voltage refers to the maximum value or the minimum value of the sinusoidal discharge voltage.

  The correction means is a capacitive component detected by the current detection means 24 during the start-up period until the discharge lamp FL is turned on, for example, with respect to the peak phase of the voltage corresponding to substantially zero crossing of the waveform of the leakage current component. A correction amount for correcting the delay of the peak phase of the voltage detected by the peak phase detecting means is obtained, and the delay of the phase of the voltage detected by the voltage detecting means 20 is corrected by the correction amount after the discharge lamp FL is turned on.

  The control circuit 16 includes a microprocessor (not shown) such as a microcomputer or a DSP (digital signal processor), a memory, a VCO (voltage controlled oscillator), etc., and is detected and corrected by the peak phase detecting means. A function for feedback control of the inverter circuit 12 so that the output current (discharge current) of the inverter circuit 12 detected by the current detection means 24 approaches a predetermined target value at the peak phase of the voltage corrected by the means, a remote controller (not shown), etc. A function of controlling the dimming level by the target value set corresponding to the dimming signal input by the external operation of the dimming operation means.

  As shown in FIG. 2, at the position of the peak phase of the discharge voltage VL, the leakage current component I_C is capacitive and can be considered as 0, and only the discharge current IL is detected. Since the output current is the sum of the discharge current IL and the leakage current component I_C, and the leakage current component I_C is 0 at the peak phase position of the discharge voltage VL, the output current should be detected at the peak phase of the discharge voltage VL. Thus, only the discharge current IL can be detected with a simple configuration, and the field effect transistors Q1 and Q2 of the inverter circuit 12 can be feedback-controlled by this discharge current IL, so that stable lighting can be obtained even during deep dimming. . In the present embodiment, it is assumed that feedback control is performed every cycle, for example.

  Next, a detection method for detecting the peak phase of the discharge voltage by the peak phase detection means will be described with reference to FIGS.

  The detected values of the discharge voltage and the output current are analog signals. The sampling circuit 27 (or the control circuit 16) shown in FIG. 1 is provided with sampling means for discretizing and sampling the analog signals of the discharge voltage and output current to obtain values at the respective sampling points. it can. As such sampling means, means comprising a sample / hold circuit and an A / D (analog / digital) converter is widely used. When analog signals of the discharge voltage and output current are detected by this means, sampling values that are discrete in time can be converted into numerical values. That is, the analog signal can be changed to a form in which the numerical value can be calculated by a calculation means such as a CPU.

  FIGS. 3A and 3B are conceptual diagrams when sampling an analog signal of a discharge voltage. For the sake of simplicity, it is assumed that the target is the discharge voltage VL and the discharge current IL, and that the negative potential is not generated under an arbitrary offset. When each analog signal passes through the sample / hold circuit and the A / D converter, the analog signal can be converted into a discrete amount sampled at the set sampling period Ts. At this time, the signals of the discharge voltage VL and the discharge current IL are {v [0], v [1], v [2], ...}, {i [0], i [1], i [2], ...} can be expressed as a set of discrete quantities. Since each value is digitized, a comparison operation or an arithmetic operation can be performed. Theoretically, if the frequency of the signal to be sampled is fsignal, the original signal can be reproduced from the discrete quantity if the sampling frequency fs (= 1 / Ts) is in the relationship of fs> 2 × fsignal by the sampling theorem. Therefore, the original detection signal can be reproduced by performing arbitrary complementation.

  Here, in order to know the peak phase of the discharge voltage VL, a discretized value as shown in FIG. 3B is used. When the sampled values are sequentially compared as shown in FIG. 3B, there is a relationship of v [0] <v [1] <v [2] <v [3]> v [4]> v [5]. . Using this, it can be seen that v [3] is the peak phase of the discharge voltage VL. From this, it is understood that i [3] of the discharge current IL corresponding to the peak phase v [3] of the discharge voltage VL gives the discharge current IL synchronized with the peak phase of the discharge voltage VL. In this way, the leakage voltage component I_C is detected by discretely sampling the analog signal of the discharge voltage VL to detect the peak phase of the discharge voltage VL and detecting the output current in synchronization with the peak phase of the discharge voltage VL. Only the discharge current IL except for can be easily detected.

  FIG. 4 shows how the discharge current IL is detected in the actual circuit configuration. FIG. 4A shows waveforms of the discharge voltage VL and the output current of the inverter circuit 12 input to the sample / hold circuit. FIG. 4B shows a sample result after passing through the A / D converter. Then, the detected discharge voltage VL and the output current of the inverter circuit 12 are input to the sample / hold circuit as a rectified waveform. Further, at the time of dimming, as shown in FIG. 4, the output current has a leading phase with respect to the waveform of the discharge voltage VL. At this time, v [0] <v [1] <v [2] <v [3]> v [4] is determined by using the calculation means, and the phase v [3] is the peak phase of the discharge voltage VL. Can know. I [3] which is the value of the output current of the inverter circuit 12 in this phase information corresponds to the peak phase of the discharge current IL.

  Here, the discharge voltage VL and the output current of the inverter circuit 12 are sampled simultaneously and independently, so that there is no deviation between the peak phase of the discharge voltage VL and the peak phase of the discharge current IL. Although it is desirable to have an independent sample / hold circuit and A / D converter for each detection amount as a circuit configuration, the discharge voltage VL is one circuit having the sample / hold circuit and the A / D converter. By repeating the determination of the peak phase, the acquisition of phase information, and the detection of the peak phase of the discharge current IL, sampling can be performed substantially simultaneously.

  Further, by incorporating a sample / hold circuit and an A / D converter in the microprocessor, the circuit configuration can be simplified.

  Next, FIG. 5 shows an example in which the correction means corrects the phase delay of the voltage detected by the voltage detection means 20 with respect to the phase of the discharge voltage of the discharge lamp FL.

  During the start-up period from when the power is turned on until the discharge lamp FL is lit, no discharge current flows through the discharge lamp FL, but the inverter circuit 12 oscillates. Voltage is output. At this time, a leakage current flows in the capacitance generated between the discharge lamp FL and the appliance, and correction is performed using this leakage current component.

  FIG. 5 shows the discharge voltage VL, the detection voltage VL_det detected by the voltage detection means 20, and the leakage current component I_C during the starting period. When the peak phase is detected or calculated based on the detection voltage VL_det, the peak phase VL_det peak 1 is obtained. On the other hand, when the peak phase of the detection voltage VL_det is corrected so that the leakage current component I_C becomes 0 before starting, the peak phase VL_det peak 2 is obtained. Thereby, the correction amount from the peak phase VL_det peak 1 to the peak phase VL_det peak 2 can be obtained.

  The discharge lamp lighting device 10 thus configured can be applied to a lighting fixture as shown in FIG. The lighting fixture includes a fixture main body 41 in which the discharge lamp lighting device 10 is arranged, sockets 42 to which straight tube-type discharge lamps FL are attached at both ends of the fixture main body 41, and the like.

  Next, the operation of the above embodiment will be described with reference to FIGS.

  For example, at the time of starting by external operation of the dimming operation means or when the discharge lamp FL is mounted on the instrument body 41, the booster circuit 11 is driven by turning on the commercial power source e, and the control circuit 16 is driven. Thus, the field effect transistors Q1 and Q2 are switched to output a high-frequency voltage from the inverter circuit 12.

  The control circuit 16 first performs a preheating operation. That is, a predetermined voltage level is supplied to the VCO to generate a frequency signal having a frequency f1 higher than the no-load resonance frequency f0 of the resonance circuit 13, and the control circuit 16 switches the field effect transistors Q1 and Q2 according to this frequency signal. Driven to supply the preheating high-frequency voltage V1 to the discharge lamp FL.

  As a result, a preheating current flows through the filament of the discharge lamp FL by the high frequency voltage V1, and preheating is performed for a predetermined time.

  When this preheating operation is completed, the control circuit 16 operates the VCO according to the voltage signal level from the voltage detecting means 20, and the VCO outputs a frequency signal corresponding to the voltage signal level. Therefore, the VCO reduces the frequency of the output frequency signal to near the resonance frequency f 0 of the resonance circuit 13. For this reason, the operating frequency of the inverter circuit 12 rises to the frequency fs, and accordingly, the high-frequency voltage applied to the discharge lamp FL rises from the preheating and becomes the starting voltage Vs of the discharge lamp FL, and the discharge lamp FL is turned on. .

  At this time, the detection circuit 27 detects only the discharge current IL because the output current of the discharge lamp FL is detected at the timing of the peak phase of the corrected discharge voltage VL that does not include the leakage current component I_C. . For this reason, the timing at which the discharge current IL is detected by the current detection means 24 connected to the detection circuit 27 is the timing at which the high-frequency voltage becomes the starting voltage Vs, that is, the timing at which the discharge lamp FL is lit. Thus, the control circuit 16 supplies the VCO with the predetermined voltage level which is relatively high, so that the operating frequency of the inverter circuit 12 is increased to the frequency f1 by the high frequency signal output from the VCO, and is output. The voltage drops to a predetermined high frequency voltage V1. That is, the timing at which the discharge current IL is detected by the current detection means 24 substantially coincides with the timing at which the discharge lamp FL is lit, so when the discharge current IL is detected by the current detection means 24, the current of the discharge lamp FL is instantaneously generated. A desired relatively low current value is set.

  At the same time, the control circuit 16 gradually increases the target value of the discharge current IL, so that the discharge lamp FL is turned on in a fade-in manner. Here, when the change amount of the dimming signal set by the external operation of the dimming operation means is less than a preset predetermined value, the discharge current IL is made to follow the target value with a value corresponding to this change amount, When the change amount of the dimming signal is equal to or larger than a predetermined value set in advance, the discharge current IL is made to follow the target value with a predetermined upper limit value.

  FIG. 8 shows the discharge voltage VL, output current, and light quantity of the discharge lamp FL from preheating to starting lighting. FIG. 8A shows the discharge voltage VL, FIG. 8B shows the output current including the leakage current I_C, and FIG. 8C shows the light quantity of the discharge lamp FL detected by, for example, a photodiode. In the period T1, the discharge lamp FL is preheated, and at the timing T2, the discharge lamp FL is turned on. At this time, the overshoot of the discharge current IL became 10% or less (almost 0) of the target value, and the discharge current IL reached the target value within 1 msec. Further, the brightness of the discharge lamp FL at the time of starting was instantaneously 5% or less.

  Thereafter, the inverter circuit 12 supplies the high frequency voltage V1 to the discharge lamp FL so that the discharge lamp FL maintains a predetermined discharge voltage VL.

  After the discharge lamp FL is turned on, the phase delay of the voltage detected by the voltage detecting means 20 can be corrected by the correction amount obtained during the starting period.

  As described above, according to the embodiment, the inverter circuit 12 is controlled by the discharge current of the discharge lamp FL by feedback controlling the field effect transistors Q1 and Q2 of the inverter circuit 12 by the current detected by the current detection means 24. Accurate feedback control is performed, and the control circuit 16 lowers the operating frequency at least after the end of the preheating operation and supplies the starting voltage Vs, which is a relatively high frequency voltage to that of the preheating, to the discharge lamp FL and the current detection means 27 When the discharge current IL of the discharge lamp FL is detected by the inverter circuit 12 can be controlled so that the current of the discharge lamp FL becomes a desired current value instantaneously, a configuration for detecting the lighting of the discharge lamp FL is provided separately. The timing of lighting the discharge lamp FL can be accurately detected. As a result, the discharge lamp FL can be started to light up gradually like a light bulb without shining brightly for a moment, and the discharge lamp FL to such an extent that even a low dimming rate does not cause the human eyes to feel a flash. Can be turned on.

  Further, feedback control of the field effect transistors Q1 and Q2 of the inverter circuit 12 by the control circuit 16 is performed at a predetermined short period, for example, current detection means, at least in the process from the end of the preheating operation to the desired lighting of the discharge lamp including the start time. By performing the current detection every 27 cycles, the responsiveness of the feedback control can be further improved, and the discharge lamp FL can be turned on and started without being lit brightly for a moment.

  Further, by gradually increasing the target value of the output current after the pre-heating operation of the discharge lamp FL to gradually increase the light quantity of the discharge lamp FL, until the desired lighting state is achieved despite the discharge lamp FL. Fade-in lighting can be performed without illuminating for a moment.

  When the discharge lamp FL is mounted or when the discharge lamp FL is turned off, for example, when a dimming signal is input by an external operation using a dimming operation means such as a remote controller, the discharge lamp FL is mounted. In this case, or in response to an external operation, the discharge lamp FL can be gradually turned on.

  Furthermore, in the case where the light amount of the discharge lamp FL is made to follow the change amount of the dimming signal input by the external operation of the dimming operation means, for example, when the change amount is large, the change in the light amount of the discharge lamp FL However, in this embodiment, the follow-up ability of the light quantity of the discharge lamp FL according to the amount of change in the dimming signal input by the external operation of the dimming operation means is sometimes felt. By changing it, dimming with less discomfort to human eyes becomes possible.

  Specifically, when the change amount of the dimming signal input by the external operation of the dimming operation means is less than a predetermined value, the current of the discharge lamp FL is made to follow the target value with a value corresponding to this change amount. When the amount of change in the dimming signal input by an external operation is greater than or equal to a predetermined value, the current of the discharge lamp FL is made to follow the current to the target value relatively slowly at a predetermined upper limit value. It can be set so that the follow-up of the light quantity is not too late or too early.

  Moreover, since the inverter circuit 12 can be feedback controlled by the current detected by the current detection means 24 at the timing of the peak phase of the discharge voltage of the discharge lamp FL, the phase of the voltage detected by the voltage detection means 20 can be controlled even during deep dimming. The inverter circuit 12 can be feedback-controlled by the discharge current IL excluding the influence of the delay, and deep dimming can be performed.

  The correction means uses, for example, a data table in which a correction amount necessary for correcting the phase delay of the voltage detected by the voltage detection means 20 with respect to the phase of the discharge voltage of the discharge lamp FL is registered in advance. The phase delay of the voltage detected by the voltage detection means 20 may be corrected by a correction amount registered in the data table. In this case, the data table is provided in the detection circuit 27 or the control circuit 16.

  Further, the voltage detection means and the current detection means can be arbitrarily configured, and voltage detection is performed with respect to the peak phase of the discharge voltage VL of the discharge lamp FL corresponding to the voltage detection means and the current detection means. If the phase delay of the voltage detected by the means can be corrected, the peak phase detecting means and the correcting means can be arbitrarily configured.

It is a circuit diagram of a discharge lamp lighting device showing an embodiment of the present invention. It is a wave form diagram which shows the relationship between the discharge voltage, discharge current, and leakage current of a discharge lamp lighting device same as the above. The detection method which detects the peak phase of discharge voltage with a discharge lamp lighting device same as the above is shown, (a) is the waveform diagram of discharge voltage and discharge current, (b) is the waveform diagram which sampled the discharge voltage and discharge current. The detection method is shown, wherein (a) is a waveform diagram of the discharge voltage and discharge current, and (b) is a waveform diagram obtained by sampling the discharge voltage and discharge current. It is a wave form diagram which shows the relationship between the discharge voltage of a discharge lamp lighting device same as the above, a detection voltage, and a leakage current component. It is a perspective view of the lighting fixture to which the same discharge lamp lighting device is applied. It is a graph which shows the relationship between the frequency of a discharge lamp lighting device same as the above, and the output voltage and discharge voltage of the secondary side of a resonant circuit. It is a waveform diagram showing the relationship between the discharge voltage of the discharge lamp lighting device, the output current and the amount of light of the discharge lamp, (a) is a waveform diagram of the envelope of the discharge voltage, (b) is a waveform of the envelope of the output current FIG. 4C is a waveform diagram of the envelope of the light quantity of the discharge lamp.

10 Discharge lamp lighting device
12 Inverter circuit
13 Resonant circuit
16 Control circuit as control means
24 Current detection means
Resonant capacitor that is a C2 capacitor
FL discharge lamp L Resonance inductance as an inductor
Q1, Q2 Field effect transistors as switching elements

Claims (6)

An inverter circuit that converts a DC voltage into a high-frequency voltage by the operation of the switching element;
A resonant circuit comprising an inductor and a capacitor connected in series between the outputs of the inverter circuit and resonating in response to a high frequency voltage;
A discharge lamp connected across the capacitor of the resonant circuit and lit by the resonant action of the resonant circuit;
From the current flowing in the discharge lamp after the preheating period and during the start-up period of the discharge lamp, the leakage current that flows outside the discharge lamp by the capacitive component without flowing into the discharge lamp during the start-up period of the discharge lamp. Current detection means for detecting the removed current;
Based on the current detected by the current detection means, feedback control is performed on the switching element of the inverter circuit. During preheating, the discharge lamp is preheated with a voltage that does not light the discharge lamp, and at least at the start after the preheating operation is completed. The inverter circuit detects the current so that the current of the discharge lamp becomes a desired current value when the frequency is lowered and a high frequency voltage higher than that at the time of preheating is supplied to the discharge lamp and the current excluding the leakage current is detected by the current detecting means. Control means for controlling by means of the feedback control at every period when the means detects current;
A discharge lamp lighting device comprising: The feedback control of the switching element of the inverter circuit by the control means is performed at a predetermined short period at least in the process from the end of the preheating operation to the desired lighting of the discharge lamp including the starting time, and the current target after the end of the preheating operation The discharge lamp lighting device according to claim 1, wherein the light quantity of the discharge lamp is gradually increased by gradually increasing the value to obtain a desired lighting state. The discharge lamp lighting device according to claim 1 or 2, wherein the control means starts the discharge lamp when the discharge lamp is mounted. The discharge lamp lighting device according to any one of claims 1 to 3, wherein the control means starts the discharge lamp when a dimming signal is input by an external operation while the discharge lamp is turned off. 5. The discharge lamp lighting device according to claim 4, wherein the control means changes the followability of the light amount of the discharge lamp according to a change amount of the dimming signal input by an external operation. When the change amount of the dimming signal input by the external operation is less than the predetermined value, the control means causes the discharge lamp current to follow the target value with a value corresponding to the change amount, and is input by the external operation. 6. The discharge lamp lighting device according to claim 5, wherein when the amount of change in the dimming signal is equal to or greater than a predetermined value, the current of the discharge lamp is made to follow the target value at a predetermined upper limit value.

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