JP4089153B2 - Discharge lamp lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable to remove noise as much as possible and to enable a high speed treatment of discharge lamp control. SOLUTION: This device has detection parts 5 to 8 for detecting a discharge lamp voltage, a discharge lamp current, a power supply voltage and a lighting time, an A/D converter 42 to A/D conversion detected signals from the respective detecting parts 5 to 8 by switching a mulitplexer 41, a signal processing part 43 for obtaining data for operation from the A/D converted detected data according to a prescribed processing method, a calculation part 44 for obtaining control data to control an output supplied from a discharge lamp-lighting circuit 2 to a discharge lamp 1 from the data for the calculation, and a change control part 441 for changing at least either a fetching action of the detected signals at the A/D converter 42 or a processing method in the signal processing part 43, according to the operation status of the discharge lamp 1. By making the processing method or the like switched appropriately by the change control part 441 according to the action state of the discharge lamp 1, removal of the noise as much as possible and a high speed treatment of a discharge lamp control can be made.

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a discharge lamp lighting device such as a metal halide lamp, and relates to a lamp lighting device such as an automobile headlamp or a liquid crystal projector.
[0002]
[Prior art]
  The discharge lamp lighting device applies a high voltage to the discharge lamp and causes a large current to flow to light the discharge lamp. Therefore, the discharge lamp lighting circuit becomes a large noise generation source from the viewpoint of the apparatus. However, in order to start lighting accurately and maintain the lighting state appropriately, it is necessary to supply power to the discharge lamp with high accuracy. For this reason, the detection voltage from each part eliminates noise. Therefore, it is necessary to control the power supply without being affected by noise. Conventionally, noise is removed by passing a noise filter when inputting the detection voltage to the A / D converter, or by using an A / D converter that is resistant to noise as the A / D converter.
[0003]
[Problems to be solved by the invention]
  In the above method, since A / D conversion takes time and control is delayed, control with high accuracy is impossible. In addition, in order to perform A / D conversion at high speed, it is possible to increase the data capturing speed by using an A / D converter in parallel for each of a plurality of detected voltages. There is a problem that the cost increases due to the use of a plurality of vessels.
[0004]
  The present invention has been made in view of the above, and at least one of a plurality of detection data capturing operations and a processing method for obtaining calculation data from the detection data according to the operating state of the discharge lamp is changed. An object of the present invention is to provide a discharge lamp lighting device that removes influence as much as possible and performs lighting lamp lighting control with high accuracy.
[0005]
[Means for Solving the Problems]
  The discharge lamp lighting device according to the first aspect of the invention includes a plurality of detection means for detecting a plurality of elements related to the operating state of the discharge lamp controlled to be turned on by the discharge lamp lighting circuit, and a detection signal from each detection means. Capture means for converting to digital detection data and capturing data, and captured detection dataBy processing or averaging forGet calculation dataProcessA signal processing unit; a calculation unit for obtaining control data for controlling an output supplied from the discharge lamp lighting circuit to the discharge lamp from the calculation data; and a capturing unit according to an operating state of the discharge lamp. Change control means for changing at least one of the detection signal capturing operation and the processing method in the signal processing means.The change control means changes the number of times of taking-in from the take-in means according to the operating state of the discharge lamp as a change in the operation of taking in the detection signal in the take-in means according to the operating state of the discharge lamp. Weighted according to the type of detection signalIt is characterized by comprising the above.
[0006]
  According to this configuration, a plurality of elements related to the operating state of the discharge lamp are detected by each detection means, and these detection signals are converted into digital detection data and captured by the capture means. The captured detection data isThrough processing or averaging,It is used as calculation data. The calculation data is processed by the calculation means to become control data for controlling the output supplied from the discharge lamp lighting circuit to the discharge lamp. Then, at least one of the detection signal capturing operation by the capturing unit and the processing method by the signal processing unit is changed by the change control unit according to the operating state of the discharge lamp. In this way, the change control means appropriately switches the processing method according to the operating state of the discharge lamp, so that noise can be removed as much as possible and high-speed processing of the discharge lamp control can be performed.
[0007]
  Further, the change control means sets the number of acquisitions from the acquisition means by weighting according to the type of the detection signal, and weights each detection signal as an element for monitoring the operation state, that is, detection. By appropriately thinning out the signal capture, the detection signal necessary for high-speed processing can be sampled with emphasis and effectiveness.
[0008]
  According to a second aspect of the present invention, the change control means is provided immediately after the discharge lamp is turned on and thereafter.,in frontThe processing method in the signal processing meansThe lawAccording to this configuration, the operation state of the discharge lamp shifts from the transient state to the stable state immediately after the discharge lamp is turned on and thereafter.,Processing methodThe lawBy changing, noise removal and high-speed processing are suitably performed in each operation state.
[0009]
  According to a third aspect of the present invention, the change control means is configured such that the data taken in by the take-in means becomes the calculation data before the discharge lamp is turned on. A rapid decrease in voltage and a rapid increase in discharge current associated with the start can be reliably detected, and it is possible to smoothly and smoothly shift to drive control after the start of discharge, and high-precision control can be realized.
[0010]
  According to a fourth aspect of the present invention, there is provided storage means for previously storing an alternative value corresponding to detection data immediately after lighting, and the change control means calculates the alternative value from the storage means immediately after the discharge lamp is turned on. According to this configuration, an alternative value is adopted as the discharge lamp current immediately after the start of discharge so that it is not affected by the noise of the inrush current that occurs immediately after the start of discharge. Stability immediately after lighting of the discharge lamp is ensured, and high-speed processing is possible.
[0011]
  According to a fifth aspect of the present invention, when the change control means turns off after the discharge lamp is turned on, the data taken in by the take-in means is used as the calculation data. When the light is turned off due to some influence, the fetched data is directly processed by the calculation means, so that high-speed processing for returning to relighting is possible.
[0012]
  Claim6In the described invention, the change control means changes the number of times of taking-in by the taking-in means according to the discharge lamp voltage detected by the detecting means. According to this configuration, the discharge lamp voltage can be increased or decreased. Accordingly, that is, depending on the magnitude of the unwanted radiation noise, the number of samplings is decreased as the discharge lamp voltage is higher and is increased as the discharge lamp voltage is lower. Regardless, it becomes possible to remove uniformly.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
  FIG. 1 is an overall configuration diagram of a discharge lamp lighting device according to the present invention. The discharge lamp lighting device supplies a discharge lamp lighting circuit 2 for supplying a pulsed drive signal that can be adjusted for lighting to the discharge lamp 1, and a required power source for driving the discharge lamp lighting circuit 2 and each section. A power supply 3 and a control circuit block 4 for performing lighting control in the discharge lamp lighting circuit 2 are provided, and a plurality of detection units for detecting a plurality of elements related to the operating state of the discharge lamp 1 are provided. In the present embodiment, the plurality of detectors include a discharge lamp voltage detector 5 that detects the voltage across the discharge lamp 1, a discharge lamp current detector 6 that detects the current flowing through the discharge lamp 1, and a power supply abnormality from the voltage of the power supply 3. By receiving a lighting operation to the power supply voltage detection unit 7 for detection and a lighting instruction operating unit (not shown), a signal from the discharge lamp lighting circuit 2, or by optically detecting the lighting of the discharge lamp 1 The lighting time detector 8 measures the lighting time.
[0014]
  The multiplexer 41 selectively switches and connects each of the detection units 5 to 8 and the A / D converter 42, and detects signals from the connected detection units to the A / D converter 42 in a so-called time division manner. Let them enter. In the present embodiment, the A / D converter 42 employs a successive approximation type that performs A / D conversion at high speed, and converts (samples) the detection signal input through the multiplexer 41 into digital detection data. The multiplexer 41 and the A / D converter 42 constitute a taking-in means 140.
[0015]
  The signal processing unit 43 performs, for example, an average process from the A / D converted detection data, and obtains reference data for calculation used in the calculation unit 44 described below.
[0016]
  The arithmetic unit 44 controls power output from the discharge lamp lighting circuit 2 to the discharge lamp by performing power calculation from one or more types of processing data from the signal processing unit 43 or from an alternative value as will be described later. Control data is output. For example, when the discharge lamp lighting circuit 2 is an inverter system, it is data for controlling the operation timing of the switching element in the inverter. Further, the arithmetic unit 44 receives input data from the signal processing unit 43, changes the connection state to the multiplexer 41, A / D conversion processing for the A / D converter 42, and changes in the data processing method for the signal processing unit 43. A control program for giving instructions is provided. In other words, the calculation unit 44 includes a microcomputer (not shown), a ROM that stores a control program, a RAM that temporarily stores sequential processing contents, a timer, and the like, and includes control data generation (power calculation) processing. A function as a change control unit 441 for instructing a change in the processing method and the like is provided.
[0017]
  The change control unit 441, which is a partial function unit of the calculation unit 44, can employ various embodiments as a method for generating control data to be output to the discharge lamp lighting circuit 2. Each embodiment will be described below. Note that the change control unit 441 includes a function realizing unit according to each embodiment by a microcomputer and an operation program inside the calculation unit 44, and will be described together in the following operation description.
[0018]
  Embodiment 1
  In the first embodiment, noise components are removed by averaging the detected data from the respective detection units sampled by the A / D converter 42 by the signal processing unit 43 using, for example, a predetermined number of data. The detection data from which the noise has been removed is guided to the calculation unit 44.
[0019]
  FIG. 2 is a flowchart for explaining the operation of the first embodiment. In the first embodiment, first, the multiplexer 41 is controlled based on a predetermined sampling period (the same applies to the following examples), and the discharge lamp voltage, discharge lamp current, power supply voltage, and lighting are performed once or a predetermined number of times. Each time detection signal is taken into the A / D converter 42 and converted into digital detection data (steps S1 to S4), and the signal processing unit 43 averages each detection data (step S5). Next, abnormality determination is performed based on criteria such as whether the processed data, that is, the calculation data is within or outside the allowable range (step S6). If abnormal, the process proceeds to step S15 described later, and if normal, lighting determination is performed. Is performed (step S7). Here, if it is determined that the discharge lamp voltage does not decrease to a predetermined value, or if the discharge lamp current does not flow, or the like, the process returns to step S1 and this process is repeated until it is determined that the discharge lamp is lit.
[0020]
  On the other hand, when it is determined that the discharge lamp 1 is lit, the multiplexer 41 is controlled so that the detection signals for the discharge lamp voltage, discharge lamp current, power supply voltage, and lighting time for one or a predetermined number of times are A. The data is taken in by the / D converter 42 and converted into digital detection data (steps S8 to S11), and the signal processing unit 43 averages each detection data (step S12). Next, abnormality determination is performed based on a criterion such as whether the calculation data after processing is within or outside the allowable range in the lighting state (step S13). If abnormal, the process proceeds to step S15 described later. Power calculation processing is performed based on the calculation data (step S7). For example, in the case where a control program for gradually reducing the power as time elapses from immediately after lighting is stored in the ROM, the calculation process is performed so that the detected release is performed along the power control based on the control program. The calculation is performed using the lamp voltage, current, etc., and the process returns to step S8. As long as it is determined that the calculation data is normal, steps S8 to S14 are repeatedly executed.
[0021]
  In step S15, the multiplexer 41 is controlled again, and the detection signals for the discharge lamp voltage, the discharge lamp current, the power supply voltage, and the lighting time for one or a predetermined number of times are taken into the A / D converter 42 and digitally converted. The detection data is converted into detection data (steps S15 to S18), and the signal processing unit 43 averages each detection data (step S19). Next, abnormality determination is performed based on a criterion such as whether the processed calculation data is within or outside the allowable range before and after lighting (step S20). The process of S20 is repeated, and if it is determined that the process has returned to normal, the process returns to the first step S1.
[0022]
  As described above, in the first embodiment, by removing noise as much as possible by signal processing, it is possible to perform higher-speed processing than those using a conventional filter or using an integral type.
[0023]
  Embodiment 2
  In the second embodiment, when a large current is required immediately after lighting, unnecessary radiation noise from the discharge lamp 1 and the discharge lamp lighting circuit 2 is large, and therefore noise mixed in the outputs of the detection units 5 to 8 is also large. Therefore, the change control unit 441 changes the signal processing method in accordance with the magnitude of noise expected from the lighting state of the discharge lamp 1.
[0024]
  FIG. 3 is a flowchart for explaining the operation of the second embodiment. In the second embodiment, first, the multiplexer 41 is controlled, and detection signals for a predetermined number of discharge lamp voltages, discharge lamp currents, power supply voltages, and lighting times are taken into the A / D converter 42 and converted into digital detection data. Conversion is performed (steps S31 to S34), and the signal processing unit 43 averages N1 detection data for each of these detection data (step S35). During this period, the light is not lit yet, so the noise is small. Therefore, a small value is set as the data sampling number N1. Next, abnormality determination is performed based on criteria such as whether the averaged data is within or outside the allowable range (step S36). If abnormal, the process proceeds to step S45 described later, and if normal, lighting determination is performed. (Step S37). Here, if it is determined that the discharge lamp voltage does not decrease to a predetermined value, or that the discharge lamp current does not flow, or the like, the process returns to step S31 and this process is repeated.
[0025]
  On the other hand, when it is determined that the discharge lamp 1 is lit, the multiplexer 41 is controlled to detect a predetermined number of discharge lamp voltage, discharge lamp current, power supply voltage, and lighting time detection signals. 42, and is converted into digital detection data (steps S38 to S41). The signal processing unit 43 averages N2 pieces of detection data for each detection data (step S42). At this time, since it is immediately after lighting that can be recognized from the lighting time data from the lighting time detector 8, the noise is large, and therefore it is necessary to prioritize increasing the noise removal rate rather than the processing speed. A large value is set as the sampling number N2. Next, abnormality determination is performed based on criteria such as whether the averaged data (calculation data) is within or outside the permissible range in the lighting state (step S43). If abnormal, the process proceeds to step S45, which will be described later, and is normal. If there is, a power calculation process is performed based on the calculation data (step S44), and the process returns to step S38. As long as the calculation data is determined to be normal, steps S38 to S44 are repeatedly executed. In this repetitive loop, the lighting state becomes stable with the passage of time after lighting that can be recognized from the lighting time data from the lighting time detector 8, and the noise is reduced, so that the original processing speed In order to achieve the above, the change control unit 441 is changed so that the value of the sampling number N2 gradually decreases in accordance with the elapsed time. The contents of this gradual change are stored in the control program, and for example, are made to be made every sampling or every predetermined number of times until a predetermined number is reached.
[0026]
  In step S45, the multiplexer 41 is controlled again, and detection signals for the discharge lamp voltage, discharge lamp current, power supply voltage, and lighting time for a predetermined number of times are taken into the A / D converter 42 and converted into digital detection data. Then, the signal processing unit 43 averages N3 pieces of detection data for each of these pieces of detection data (step S49). Next, abnormality determination is performed based on criteria such as whether the processed calculation data is within or outside the allowable range before and after lighting (step S50). On the other hand, if it is determined that the process returns to normal, the process returns to the first step S31. At this time, the sampling number N3 is set from the lighting time data from the lighting time detector 8.
[0027]
  As described above, in the second embodiment, the sampling number N2 is changed so as to be gradually decreased according to the time immediately after lighting, so that a large noise is generated due to the high discharge current level immediately after lighting. In view of the fact that while the number of samplings is increased to increase the noise removal rate, the noise decreases with the passage of time, it is possible to control to shift to processing that prioritizes processing speed over noise removal. Control with high accuracy can be realized in the entire period after lighting.
[0028]
  Embodiment 3
  In general, in order for the discharge lamp 1 to start discharging, a voltage is applied to the discharge lamp, and a dielectric breakdown is caused by superimposing a higher voltage pulse with an igniter, thereby starting the discharge. There is a need to shift to sustained control. Therefore, the calculation unit 44 needs to quickly detect the start of discharge of the discharge lamp 1 and perform power control. The discharge of the discharge lamp 1 can be started by detecting a rapid decrease in the discharge lamp voltage or a rapid increase in the discharge lamp current. However, the signal processing unit 43 applies a plurality of sampling data to remove noise. If averaging processing is performed, there is a possibility that a sudden rise or fall may be overlooked (cannot be detected), or the detection may be delayed, and the transition to lighting control may not be performed properly. is there. Therefore, in the third embodiment, before starting the discharge, the detection data of the A / D converter 42 is not guided to the signal processing unit 43 to perform the signal processing, that is, as it is (that is, the processing by the signal processing unit 43). In the method, the input detection data is not processed but is output as it is) and used as an input to the calculation unit 44, and the time from detection to control is increased to a real time order. This is because before the discharge starts, since the discharge lamp 1 has not yet been discharged, unnecessary radiation noise from the discharge lamp 1 does not appear or is quite small, so that noise may be mixed in the detection signals from the detection units 5 to 8. This is in consideration of almost none.
[0029]
  FIG. 4 is a flowchart for explaining the operation of the third embodiment. In the third embodiment, first, the multiplexer 41 is controlled, and detection signals for the first discharge lamp voltage, discharge lamp current, power supply voltage, and lighting time are taken into the A / D converter 42 and converted into digital detection data. The signal is converted (steps S61 to S64), passed through the signal processing unit 43, and led to the calculation unit 44. Next, abnormality determination is performed based on criteria such as whether the detected data is within or outside the allowable range (step S65). If abnormal, the process proceeds to step S74 described later, and if normal, lighting determination is performed (step S66). ). Here, if it is determined that the discharge lamp voltage does not decrease to a predetermined value, or if the discharge lamp current does not flow, or the like, the process returns to step S61, and this process is repeated until it is determined that the discharge lamp is lit.
[0030]
  In the third embodiment, the process when it is determined that the discharge lamp is lit (steps S67 to S73) and the process when it is determined that the discharge lamp is abnormal (NO in steps S65 and S72) (steps S74 to S79). Are the same as steps S8 to S14 and steps S15 to S21 described in the first embodiment, and a description thereof will be omitted.
[0031]
  As described above, in the third embodiment, since the change control unit 441 guides the detection data to the calculation unit 44 as it is before the start of discharge, high-speed processing is realized, and the voltage accompanying the start of discharge is rapidly increased. It is possible to reliably detect a drop or a sudden rise in the discharge current, and it is possible to smoothly and smoothly shift to drive control after the start of discharge, so that high-precision control can be realized.
[0032]
  Embodiment 4
  Immediately after the discharge of the discharge lamp 1 starts, a current having a peak such as an inrush current may be superimposed on the discharge lamp current. When this inrush current is A / D converted and input to the calculation unit 44, control to suppress the current excessively works to cause the discharge lamp 1 to turn off or to make the rise of the luminous flux of the discharge lamp 1 unstable. Cause. Therefore, in the fourth embodiment, for example, an empirical / experimental substitute value is stored as a value in place of the actual detection value in the above-described ROM in the calculation unit 44, discharge starts, and an inrush current is generated. During the flow, A / D conversion is not performed on the detection signal from the discharge lamp current detection unit 6, and an alternative value is read from the ROM in the calculation unit 44 and set in the calculation unit 44, so that this value is regarded as detection data. Thus, power control is performed to ensure stability immediately after the discharge lamp is turned on.
[0033]
  FIG. 5 is a flowchart for explaining the operation of the fourth embodiment. In the fourth embodiment, first, the multiplexer 41 is controlled, and the detection signals of the discharge lamp voltage, the discharge lamp current, the power supply voltage, and the lighting time are taken into the A / D converter 42 and converted into digital detection data ( In steps S81 to S84, the signal processing unit 43 performs an average process for each detection data (step S85). Next, abnormality determination is performed based on criteria such as whether the processed calculation data is within or outside the allowable range (step S86). If abnormal, the process proceeds to step S101 to be described later, and if normal, lighting determination is performed. (Step S87). Here, if it is determined that the discharge lamp voltage does not decrease to a predetermined value, or if the discharge lamp current does not flow, or the like, the process returns to step S81 and this process is repeated until it is determined that the lamp is lit.
[0034]
  On the other hand, when it is determined that the discharge lamp 1 has been turned on, the multiplexer 41 is controlled to detect the discharge lamp voltage, the power supply voltage, and the lighting time detection signals other than the discharge lamp current into the A / D converter 42. Are converted into digital detection data (steps S88 to S90), and each of the detection data is processed by the signal processing unit 43, and an alternative value prepared in advance is read out from the ROM and calculated. Is set in the unit 44 (step S91). Next, abnormality determination is performed based on a criterion such as whether the data after the arithmetic processing is within the allowable range in the lighting state (step S92). If abnormal, the process proceeds to step S101 to be described later. Arithmetic processing is performed (step S93).
[0035]
  Subsequently, the multiplexer 41 is controlled again, and this time, each detection signal of the discharge lamp voltage, discharge lamp current, power supply voltage, and lighting time is taken into the A / D converter 42 and converted into digital detection data ( In steps S94 to S97, the signal processing unit 43 performs processing for each detection data (step S98). In this case, since it is considered that the inrush current immediately after lighting has already occurred, the detection data from the discharge lamp current detector 6 is used as the discharge lamp current. Next, abnormality determination is performed based on criteria such as whether the processed data is within or outside the allowable range after lighting (step S99). If abnormal, the process proceeds to step S101, and if normal, the process returns to step S94. In the loop of steps S94 to S100, for example, when a control program for gradually reducing the power as time elapses immediately after lighting is stored in the ROM, the power control based on the control program is performed. The calculation is executed using the detected discharge lamp voltage, current, etc., and as long as the calculation data is determined to be normal, steps S94 to S100 are repeatedly executed.
[0036]
  In addition, since step S101-S106 in Embodiment 4 are the same as step S15-S20 of Embodiment 1, description is abbreviate | omitted.
[0037]
  As described above, in the fourth embodiment, an alternative value is adopted as the discharge lamp current immediately after the start of discharge so as not to be affected by noise such as an inrush current generated immediately after the start of discharge. Stability immediately thereafter is ensured, and high-speed processing is possible.
[0038]
  Embodiment 5
  Even after the discharge lamp is turned on, the discharge lamp may be turned off for some reason. In this case, it is necessary to relight the lamp at a high speed. Therefore, in the fifth embodiment, since unnecessary radiation noise from the discharge lamp disappears in response to the discharge lamp being extinguished, noise is not mixed in the detection data. Therefore, a processing method using the detection data as it is is adopted. Thus, it is guided directly to the calculation unit 44.
[0039]
  FIG. 6 is a flowchart for explaining the operation of the fifth embodiment. Since steps S111 to S124 in the fifth embodiment are the same as steps S1 to S14 in the first embodiment, description thereof will be omitted.
[0040]
  When the lighting of the discharge lamp 1 is normally continued in steps S118 to S124, if an abnormality, that is, a rapid increase in the discharge lamp voltage or a rapid decrease in the discharge lamp current (extinguishment) is detected in step S123, step S125 and subsequent steps. Transition to control.
[0041]
  First, the multiplexer 41 is controlled, and each detection signal of discharge lamp voltage, discharge lamp current, power supply voltage, and lighting time is taken into the A / D converter 42 and converted into digital detection data (steps S125 to S128). Through the signal processing unit 43, the signal processing unit 43 is guided to the calculation unit 44 as it is. Then, abnormality determination based on a criterion such as whether the detected data is within or outside the allowable range is directly performed (step S129). If abnormal, the process returns to step S125 and the same processing is repeated. Return to S111.
[0042]
  As described above, in the fifth embodiment, the detection data is directly processed by the calculation unit 44 when the light is extinguished due to some influence while the lighting is continued. Therefore, high-speed processing for returning to relighting is possible.
[0043]
  Embodiment 6
  The discharge lamp lighting circuit 2 increases the power supplied to the discharge lamp 1 at the start of lighting, and controls the power to be reduced with the passage of time so that the rise of the luminous flux of the discharge lamp 1 is improved. At this time, the unnecessary radiation noise generated from the discharge lamp 1 also decreases with the passage of time after the discharge lamp 1 is turned on. Therefore, in the sixth embodiment, the change control unit 441 changes the data sampling of the signal processing in the signal processing unit 43 with the time after lighting. That is, the number of samplings is increased immediately after lighting, and the number of samplings is decreased as time passes, so that the influence of noise is uniformly removed regardless of the elapsed time after lighting.
[0044]
  FIG. 7 is a flowchart for explaining the operation of the sixth embodiment. In FIG. 7, for example, the first embodiment is employed until the discharge lamp 1 is turned on. When it is determined that the discharge lamp 1 has been lit, a timer T is started (step S131), and the elapsed time from the lighting of the discharge lamp 1 is measured and monitored. Next, it is determined whether or not the elapsed time T has exceeded the first predetermined value T0 (step S132), and if not, it is taken into the A / D converter 42 from each of the detection units 5 to 8 via the multiplexer 41. In addition, averaging processing is performed on the sampling data for N1 times (step S133). On the other hand, if the elapsed time T exceeds T0, it is determined whether or not the elapsed time T exceeds a predetermined value T1 (> T0) (step S134). An averaging process is performed on the sampling data of N2 (<N1) times taken into the A / D converter 42 via 41 (step S135). On the other hand, if the elapsed time T exceeds T1, it is determined whether or not the elapsed time T exceeds a predetermined value T2 (> T1) (step S136). An averaging process is performed on the sampling data of N3 (<N2) times taken into the A / D converter 42 via 41 (step S137). On the other hand, if the elapsed time T exceeds T2, it is determined whether or not the elapsed time T exceeds a predetermined value T3 (> T2) (step S138). An averaging process is performed on the sampling data of N4 (<N3) times taken into the A / D converter 42 via 41 (step S139). When the elapsed time T exceeds T3, the averaging process is performed on the sampling data for N5 (<N4) times taken into the A / D converter 42 from the detection units 5 to 8 via the multiplexer 41, respectively. (Step S140). Each average processed data is guided to the calculation unit 44 as calculation data.
[0045]
  As described above, in the sixth embodiment, the number of samplings is increased immediately after lighting, and the number of samplings is decreased as time passes, so that the influence of noise can be uniformly removed regardless of the elapsed time after lighting. It becomes.
[0046]
  Embodiment 7
  In the seventh embodiment, the discharge lamp voltage is used instead of the lighting time of the sixth embodiment. By changing the sampling number of the detection data in the signal processing unit 43 according to the discharge lamp voltage, the noise can be reduced. Remove the effect.
[0047]
  FIG. 8 is a flowchart for explaining the operation of the seventh embodiment. In FIG. 8, for example, Embodiment 1 is adopted as the processing until the discharge lamp 1 is turned on. If it is determined that the discharge lamp 1 is turned on, the detection voltage from the discharge lamp voltage detection unit 5 is obtained by A / D conversion (step S141). Next, it is determined whether or not the discharge lamp voltage Vla exceeds the initial predetermined value Vla0 (step S142). If not, the detectors 5 to 8 pass through the multiplexer 41 to the A / D converter 42. An average process is performed on the acquired sampling data for N1 times (step S143). On the other hand, if the discharge lamp voltage Vla exceeds Vla0, it is determined whether or not the discharge lamp voltage Vla exceeds a predetermined value Vla1 (> Vla0) (step S144). The averaging process is performed on the sampling data of N2 (<N1) times, which is taken into the A / D converter 42 from 8 through the multiplexer 41 (step S145). On the other hand, if the discharge lamp voltage Vla exceeds Vla1, it is determined whether or not the discharge lamp voltage Vla exceeds a predetermined value Vla2 (> Vla1) (step S146). The averaging process is performed on the sampling data of N3 (<N2) times, which is taken into the A / D converter 42 from 8 through the multiplexer 41 (step S147). On the other hand, if the discharge lamp voltage Vla exceeds Vla2, it is determined whether or not the discharge lamp voltage Vla exceeds a predetermined value Vla3 (> Vla2) (step S148). The averaging process is performed on the sampling data of N4 (<N3) times, which is taken into the A / D converter 42 from 8 through the multiplexer 41 (step S149). When the discharge lamp voltage Vla exceeds Vla3, the average processing is performed on the sampling data for N5 (<N4) times taken into the A / D converter 42 from the detectors 5 to 8 via the multiplexer 41, respectively. Is applied (step S150). Each average processed data is guided to the calculation unit 44 as calculation data.
[0048]
  Thus, in the seventh embodiment, the number of samplings is decreased as the discharge voltage is higher and increased as the discharge lamp voltage is lower according to the level of the discharge lamp voltage, that is, according to the magnitude of the unnecessary radiation noise. The influence of noise can be uniformly removed regardless of the level of the discharge lamp voltage after lighting.
[0049]
  Embodiment 8
  In the eighth embodiment, the detection signals necessary for the high-speed processing are weighted to the detection signals from the four detection units 5 to 8 as elements for monitoring the operation state by the discharge lamp lighting circuit 2, that is, the detection signals are appropriately thinned out. The signal is sampled in a focused and effective manner. For example, the lighting time detector 8 stops taking in when a sufficient time has elapsed after the discharge and the light flux becomes stable. In addition, the power supply voltage detector 7 generally reduces the number of samplings in consideration of the fact that there is no sudden change. That is, the discharge lamp voltage and the discharge lamp current important for power control are sampled intensively. For example, the power supply voltage is in the order of once every 10 times or every 20 times the sampling of the discharge lamp voltage and the discharge lamp current. By sampling by thinning out, the discharge lamp voltage and discharge lamp current are sampled as fast as possible to improve the accuracy of power control.
[0050]
  9 and 10 are flowcharts for explaining the operation of the eighth embodiment. First, when the control is started, a count N indicating the number of samplings before lighting is initially set to 0 (step S161). Next, it is determined whether or not the count N is a multiple of 10 (step S162). Otherwise, it is determined whether or not it is a multiple of 5 (step S163). If it is not a multiple of 5, only the discharge lamp voltage and discharge lamp current are taken in and A / D converted (steps S164 and S165). Then, the signal processing unit 43 performs signal processing on the obtained detection data of the discharge lamp voltage and discharge lamp current (step S173). Next, abnormality determination is performed based on criteria such as whether the processed calculation data is within or outside the allowable range (step S174). If abnormal, the process proceeds to step S200 described later, and if normal, lighting determination is performed. (Step S175). Here, if it is determined that the discharge lamp voltage does not decrease to a predetermined value, or that the discharge lamp current does not flow, or the like, the counter N is incremented (step S176), and the process returns to step S162. If it is determined that the lamp is lit, the process proceeds to step S177.
[0051]
  Returning to step S162, if the count N is not a multiple of 10 but a multiple of 5 (YES in step S163), the detection signals of the discharge lamp voltage, the discharge lamp current, and the power supply voltage are taken in, and A / D Conversion is performed (steps S166 to S168). Then, the detected data of the discharge lamp voltage, the discharge lamp current, and the power supply voltage is subjected to signal processing by the signal processing unit 43 (step S173), then abnormality determination is performed (step S174), and further lighting determination is performed. Is performed (step S175). If it is determined that the lamp is not lit, the count N is incremented (step S176), and the process returns to step S162.
[0052]
  On the other hand, if the count N is a multiple of 10 in step S162, the detection signals of the discharge lamp voltage, discharge lamp current, power supply voltage, and lighting time are captured and A / D converted (steps S169 to S172). . Then, the obtained detection data is subjected to signal processing by the signal processing unit 43 (step S173), then abnormality determination is performed (step S174), and further lighting determination is performed (step S175). If it is determined that the lamp is not lit, the count N is incremented (step S176), and the process returns to step S162. This process is repeated until it is determined that the lighting is on.
[0053]
  Thus, in the non-lighting period, the discharge lamp voltage and the discharge lamp current are sampled for all the counts N, the power supply voltage is sampled only when the count N is a multiple of 5, and the lighting time is a count N of 10 It is sampled only when it is a multiple of. As a result, the discharge lamp voltage and the discharge lamp current are sampled 10 times, and the lighting time is 1 and the power supply voltage is 2 times. Thus, the power supply voltage and the lighting time are thinned out at a given ratio. The discharge lamp voltage and the discharge lamp current can be sampled intensively.
[0054]
  Subsequently, when it is determined in step S175 that lighting is performed, a count a indicating the number of times of sampling after lighting is initially set to 0 (step S177). Next, it is determined whether or not the count a is less than the predetermined value al (step S178). Here, if the count a is greater than or equal to al, it is determined that a predetermined time has elapsed since the lighting, and the process proceeds to step S194. On the other hand, if the count a is less than al, it is determined whether the count a is a multiple of 10 (step S179). Otherwise, it is determined whether it is a multiple of 5 (step S180). If it is not a multiple of 5, only the discharge lamp voltage and discharge lamp current are taken in and A / D converted (steps S181 and S182). Then, the signal processing unit 43 performs signal processing on the obtained detection data of the discharge lamp voltage and discharge lamp current (step S190). Next, abnormality determination is performed based on criteria such as whether the processed data is within or outside the allowable range (step S191). If abnormal, the process proceeds to step S200 described later, and if normal, power calculation is performed ( In step S192), the count a is incremented (step S193), and the process returns to step S178.
[0055]
  Returning to step S178, if the count N is less than a1 and not a multiple of 10 (NO in step S179) and a multiple of 5 (YES in step S180), the discharge lamp voltage, discharge lamp current, and power supply voltage are The detection signal is taken in and A / D converted (steps S183 to S185). The obtained detection data of the discharge lamp voltage, the discharge lamp current, and the power supply voltage are signal-processed by the signal processing unit 43 (step S190), and then abnormality determination is performed (step S191). For example, the process proceeds to step S200 described later, and if it is normal, power calculation is performed (step S192), the count a is incremented (step S193), and the process returns to step S178.
[0056]
  On the other hand, if the count N is less than a1 and a multiple of 10 in step S178 (YES in step S179), the detection signals of the discharge lamp voltage, discharge lamp current, power supply voltage, and lighting time are taken in, and A / D conversion is performed (steps S186 to S189). Then, the obtained detection data is subjected to signal processing by the signal processing unit 43 (step S190), and then abnormality determination is performed (step S191). If abnormal, the process proceeds to step S200 to be described later. If there is, the power calculation is performed (step S192), the count a is incremented (step S193), and the process returns to step S178. This process is repeated while normal lighting continues.
[0057]
  Thus, in the normal lighting period, the discharge lamp voltage and the discharge lamp current are sampled for all the counts a, the power supply voltage is sampled only when the count a is a multiple of 5, and the lighting time output is the count a. It is sampled only when it is a multiple of 10. As a result, when the discharge lamp voltage and the discharge lamp current are sampled 10 times, the lighting time output is 1 and the power supply voltage is 2 times. By thus thinning out the power supply voltage and the lighting time output, The voltage and discharge lamp current can be sampled intensively.
[0058]
  When the count a reaches the value a1 in step S178, it is determined whether or not the count a is a multiple of 10 (step S194). If it is not a multiple of 10, only the discharge lamp voltage and the discharge lamp current are taken in and A / D converted (steps S195 and S196). Then, the signal processing unit 43 performs signal processing on the obtained detection data of the discharge lamp voltage and discharge lamp current (step S190). Next, abnormality determination is performed based on criteria such as whether the processed data is within or outside the allowable range (step S191). If abnormal, the process proceeds to step S200 described later, and if normal, power calculation is performed ( In step S192), the count a is incremented (step S193), and the process returns to step S178.
[0059]
  On the other hand, if the count a is a multiple of 10 (YES in step S194), detection signals for the discharge lamp voltage, discharge lamp current, and power supply voltage are taken in and A / D converted (steps S197 to S199). The obtained detection data of the discharge lamp voltage, the discharge lamp current, and the power supply voltage are signal-processed by the signal processing unit 43 (step S190), and then abnormality determination is performed (step S191). For example, the process proceeds to step S200 described later, and if it is normal, power calculation is performed (step S192), the count a is incremented (step S193), and the process returns to step S178. This process is repeated while normal lighting continues.
[0060]
  As described above, after a predetermined time (corresponding to the count value a1) has elapsed since the lighting was normal, the discharge lamp voltage and the discharge lamp current are sampled for all of the count a, and the power supply voltage is also counted by a. Sampling is stopped only when it is a multiple of 10, while sampling is stopped during the lighting time. Thereby, by stopping the acquisition of the detection signal that is no longer necessary, the sampling opportunity of the discharge lamp voltage and the discharge lamp current can be increased, and the discharge lamp voltage and the discharge lamp current can be sampled with priority.
[0061]
  If it is determined that there is an abnormality in steps S174 and S191, the process proceeds to step S200 and subsequent steps. Since the process here is the same as steps S15 to S20 of the first embodiment, the description thereof is omitted.
[0062]
  Although the present invention has been described in terms of a configuration in which the A / D converter 42 is used as one unit and the miniaturization is realized, and the multiplexer 41 selectively captures four detection signals, the present invention is not limited to this. It is also applicable to a configuration in which four A / D converters are provided corresponding to the above.
[0063]
  FIG. 11 is an overall configuration diagram showing another circuit configuration of the discharge lamp lighting device according to the present invention. The discharge lamp lighting device is basically the same as the circuit configuration shown in FIG. 1 and has a lighting time detecting means 8, a part of the arithmetic circuit 44 having an additional function, and a direct arithmetic circuit from the A / D converter 42. The difference is that the signal line to 44 is also clearly shown on the drawing.
[0064]
  The arithmetic circuit 44 calculates a power command value to be given to the discharge lamp 1 based on detection data from the lighting time detection means 8 and the power supply voltage detection means 7. The electric power command value is set high when the discharge lamp 1 is cold, while it is lit after that, and the lighting efficiency increases because the temperature rises as the lighting time increases. Accordingly, the power command value is gradually lowered. Further, when the power supply voltage is lowered, the current value from the power supply 3 increases in order to keep giving constant power to the discharge lamp 1, so that the rating of the electronic elements in the discharge lamp lighting circuit 2 is not exceeded. It is necessary to. Therefore, when the power supply voltage decreases, the arithmetic circuit 44 controls to reduce the power command value.
[0065]
  The arithmetic circuit 44 calculates the actual power input to the discharge lamp 1 from the discharge lamp voltage detected by the discharge lamp voltage detection means 5 and the discharge lamp current detected by the discharge lamp current detection means, Control data is generated and output so that the actual input power and the power command value are the same. These controls are executed based on the same control program stored in the arithmetic circuit 44 as described above.
[0066]
  Embodiment 9
  In the ninth embodiment, the discharge lamp voltage detection means 5, the discharge lamp current detection means 6, the power supply voltage detection means 7 and the lighting time detection means 8 are used for each data of the discharge lamp voltage, discharge lamp current, power supply voltage and lighting time. For example, the noise of the voltage input to the A / D converter 42 is removed by performing an averaging process on a predetermined number of data, and the signal from which the noise component is removed is input to the arithmetic circuit 44. is there.
[0067]
  Embodiment 10
  In the tenth embodiment, when a large amount of power is required immediately after the discharge lamp 1 is lit, unnecessary radiation noise from the discharge lamp 1 and the discharge lamp lighting circuit 2 is large, and therefore noise superimposed on the detection voltage from each detection means. In view of this, the change control unit 441 changes the processing method in the signal processing circuit 43 in order to increase the noise removal rate.
[0068]
  For example, the number of samplings for averaging is increased to increase the noise removal rate rather than the signal processing speed. When a steady state is reached after sufficient time has elapsed after lighting, the power is stabilized and the noise component is reduced. Therefore, the processing speed is prioritized over the signal processing circuit 43 over the noise removal rate. Thus, power control is performed with high accuracy without being affected by noise.
[0069]
  Embodiment 11
  In general, the discharge lamp 1 starts discharging by applying a voltage to the discharge lamp 1 and then superimposing a higher voltage pulse with a pulse generator such as an igniter to cause dielectric breakdown. With this operation, the control circuit block 4 needs to quickly detect the discharge start of the discharge lamp 1 and control the power. The discharge start of the discharge lamp 1 can be detected by detecting a rapid decrease in the discharge lamp voltage or a rapid increase in the discharge lamp current, but the signal processing circuit 43 performs an averaging process to remove noise. If this is the case, a sudden current rise or voltage drop cannot be detected, or detection may be delayed. For this reason, the change control unit 441 does not perform signal processing in the signal processing circuit 43 only before the start of discharge, but directly inputs detection data from the A / D converter 42 shown in FIG. Increase the start detection speed. Further, since no unwanted radiation is generated from the discharge lamp 1 that is not discharged, the detected voltage is hardly affected.
[0070]
  Embodiment 12
  Immediately after the discharge lighting of the discharge lamp 1 is started, a current having a large peak as an inrush current is generated in the discharge lamp 1 superimposed on the discharge lamp current. When this inrush current is A / D converted by the A / D converter 42 and input to the arithmetic circuit 44, control data in a direction to suppress the current excessively is obtained, and the discharge lamp 1 is turned off or the discharge lamp 1 is turned off. Cause instability in the rise of luminous flux. Therefore, the change control unit 441 does not perform the A / D conversion of the discharge lamp current from the discharge lamp current detection means 6 while the discharge starts, the arithmetic circuit 44 shifts to the lighting control, and the inrush current flows. A preset substitute value is set in the arithmetic circuit 44, and the power is controlled by the substitute value, so that the stability immediately after the discharge lamp 1 is turned on is increased.
[0071]
  Embodiment 13
  When the discharge lamp 1 is turned on and detects any abnormality, the change control unit 441 inputs the detection data from the A / D converter 42 shown in FIG. 11 directly to the arithmetic circuit 44 through the signal line. The detection speed is increased. Further, for the noise, unnecessary radiation noise does not occur from the discharge lamp 1 that is not discharged, so that the detection voltage is hardly affected.
[0072]
  Embodiment 14
  The fourteenth embodiment is characterized in that the lighting time detecting means 8 shown in FIG. 12 is used. In the lighting time detection means 8, one end of the capacitor 81 is connected to the fixed contact of the switch 82, and a line having the resistor 83 and a series line of the resistor 84 and a predetermined power source 85 are connected to the movable contact of the switch 82, respectively. In addition, one end of the capacitor 81 is an output terminal. The switch 82 is connected to a line on the power supply 85 side when discharging starts to charge the capacitor 81, and switches to the line on the resistor 83 side to discharge when turned off, for example, a sensor that receives lighting light. It is controlled by using.
[0073]
  Then, it is set in advance by the arithmetic circuit 44 so that the power command value becomes rated when the capacitor 81 is saturated. At this time, if the discharge lamp 1 continues to be lit, the output of the lighting time detecting means 8 is saturated with the voltage of the power supply 85 and does not change. Therefore, the output of the lighting time detecting means 8 is periodically sampled immediately after lighting by the arithmetic circuit 44, and the capacitor 81 is saturated when the increase in change from the previous and current sampling values becomes 0 or below a predetermined value. Accordingly, the A / D conversion of the output of the lighting time detecting means 8 is stopped. In this way, since the four types of signals to be A / D converted can be made into three types, the time required for A / D conversion can be reduced to 3/4, and the control speed can be increased.
[0074]
  Embodiment 15
  In the fifteenth embodiment, the discharge lamp lighting device shown in FIG. 13 is employed. This device is obtained by adding a timer 45 to the discharge lamp lighting device of FIG. The timer 45 measures time according to the output from the lighting time detection means 8 when power is turned on, that is, when control is started, and outputs time data as digital data. The change control unit 441 substitutes the output of the timer 45 for the output of the lighting time detection means 8, and A / D converts the output of the lighting time detection means 8 once or several times at the start of control. After that, A / D conversion of the output from the lighting time detection means 8 is stopped. In this way, since the four types of signals to be A / D converted can be made into three types, the time required for A / D conversion can be reduced to 3/4, and the control speed can be increased.
[0075]
  Embodiment 16
  FIG. 14 is a timing chart of detection data, where (a) is a discharge lamp voltage waveform, (b) is a discharge lamp current waveform, and (c) is a diagram showing A / D conversion timing. In FIG. 14, VLA is the discharge lamp voltage, ILA is the discharge lamp current, VIN is the power supply voltage, VCIN is the lighting time, and (c) is the A / D conversion timing. Further, this detection process is repeated with a period including three or four pieces of data separated by bold lines as one cycle.
[0076]
  The lighting of the discharge lamp 1 starts when a high voltage is applied to the discharge lamp 1 and the high voltage is further superimposed by an igniter. When lighting is started, the resistance value of the discharge lamp 1 decreases and the discharge lamp voltage also decreases at the same time. Moreover, when lighting starts, the discharge lamp current starts to flow. Here, in order to reliably start the lighting of the discharge lamp 1, first, when the discharge lamp voltage is A / D converted as a value lower than a predetermined voltage threshold ((1) timing in FIG. 14), the arithmetic circuit 44 Shifts to lighting control. When the discharge lamp current is A / D converted for the first time after shifting to the lighting control ((2) timing in FIG. 14), the arithmetic circuit 44 determines whether or not the discharge lamp current is higher than a predetermined current threshold value. . Here, if the discharge lamp current has a value higher than the predetermined current threshold, the lighting control is continued, and conversely, if the discharge lamp current has a value lower than the predetermined current threshold, it is assumed that the lamp is not lit, and again By returning to the pre-lighting control and detecting the start of lighting with two types of discharge lamp voltage and discharge lamp current, malfunction due to noise is prevented.
[0077]
  Embodiment 17
  In the pre-lighting control, A / D conversion of the discharge lamp current is stopped. That is, before the discharge lamp 1 is turned on as in the A / D conversion timing of FIG. 14, the A / D conversion is performed on three types of input signals of the discharge lamp voltage, the power supply voltage, and the lighting time, and the discharge lamp 1 is turned on. When the discharge lamp voltage is A / D converted for the first time ((1) timing in FIG. 14), the arithmetic circuit 44 recognizes the lighting of the discharge lamp 1 and shifts to lighting control from the next cycle. To start A / D conversion of the discharge lamp current. Thus, by stopping the A / D conversion of the discharge lamp current in the pre-lighting control, the time from when the discharge lamp 1 is lit until the arithmetic circuit 44 recognizes the lighting and shifts to the lighting control is shortened. can do. For this reason, it is possible to prevent a large current from flowing through the discharge lamp 1 and to enable stable control.
[0078]
  Embodiment 18
  FIG. 15 is a timing chart of detection data, where (a) shows the discharge lamp voltage waveform, (b) shows the discharge lamp current waveform, and (c) shows the A / D conversion timing. In FIG. 15, VLA is the discharge lamp voltage, ILA is the discharge lamp current, VIN is the power supply voltage, VCIN is the lighting time, and (c) is the A / D conversion timing. Further, this detection process is repeated with a period including three or four pieces of data separated by bold lines as one cycle.
[0079]
  The lighting of the discharge lamp 1 starts when a high voltage is applied to the discharge lamp 1 and the high voltage is further superimposed by an igniter. When lighting is started, the resistance value of the discharge lamp 1 decreases and the discharge lamp voltage also decreases at the same time. Moreover, when lighting starts, the discharge lamp current starts to flow. Here, in order to reliably start the lighting of the discharge lamp 1, first, when the discharge lamp current is A / D converted as a value higher than a predetermined current threshold ((1) timing in FIG. 15), the arithmetic circuit 44 Shifts to lighting control. When the discharge lamp voltage is first A / D converted after the transition to the lighting control ((2) timing in FIG. 15), the arithmetic circuit 44 determines whether or not the discharge lamp voltage is lower than a predetermined voltage threshold value. . Here, if the discharge lamp voltage is lower than the predetermined voltage threshold, the lighting control is continued, and conversely, if the discharge lamp voltage is higher than the predetermined voltage threshold, it is considered that the lamp is not lit, and again. By returning to the pre-lighting control and detecting the start of lighting with two types of discharge lamp voltage and discharge lamp current, malfunction due to noise is prevented.
[0080]
  Embodiment 19
  In the pre-lighting control, A / D conversion of the discharge lamp voltage is stopped. That is, before the discharge lamp 1 is turned on as shown in the A / D conversion timing of FIG. 15, three types of input signals of the discharge lamp voltage, the power supply voltage, and the lighting time are A / D converted, and the discharge lamp 1 is turned on. When the discharge lamp current is A / D converted for the first time (timing (1) in FIG. 15), the arithmetic circuit 44 recognizes lighting of the discharge lamp 1 and shifts to lighting control from the next cycle. To start A / D conversion of the discharge lamp voltage. Thus, by stopping the A / D conversion of the discharge lamp voltage in the pre-lighting control, the time from when the discharge lamp 1 is lit until the arithmetic circuit 44 recognizes the lighting and shifts to the lighting control is shortened. can do. For this reason, it is possible to prevent a large current from flowing through the discharge lamp 1 and to enable stable control.
[0081]
  Embodiment 20.
  Immediately after the start of lighting, when a large amount of electric power is applied to the discharge lamp 1, unnecessary radiation noise from the discharge lamp 1 is also increased. In addition, the discharge lamp 1 when a sufficient time has elapsed after lighting is in a steady state, and unnecessary radiation noise emitted from the discharge lamp 1 is also reduced. Therefore, the change control unit 441 changes the signal processing data sampling in the signal processing circuit 43 with the passage of time after lighting so that the influence of noise is not easily received immediately after lighting.
[0082]
  That is, after lighting, a large number of samplings are taken and the number of samplings is reduced as time passes. For example, immediately after lighting in the signal processing circuit 43, A / D conversion values for the past 10 times are stored in memory, and the average value of the 10 data is used as the output of the signal processing circuit 43, and the number of data is reduced as the lighting time elapses. In a steady state, A / D conversion values for three times are stored in memory, and an average value of the three times of data is used as an output of the signal processing circuit 43. By performing such signal processing, a discharge lamp lighting device that is less susceptible to noise can be realized.
[0083]
  Embodiment 21.
  The change control unit 441 removes the influence of noise by changing the number of samplings used for signal processing in the signal processing circuit 43 in accordance with the discharge lamp voltage or the discharge lamp current. For example, in the signal processing circuit 43, when the value of the discharge lamp current is large, the A / D conversion values for the past 10 times are stored in memory, and the average value of the 10 times of data is used as the output of the signal processing circuit 43. As the value of the discharge lamp current becomes smaller, the number of data sampling is reduced, and in the steady state where the discharge lamp current becomes smaller, the A / D conversion values for the past three times are memorized, and the average of the three data The value is used as the output of the signal processing circuit 43. By performing such signal processing, a discharge lamp lighting device that is less susceptible to noise can be realized.
[0084]
  Embodiment 22
  The twenty-second embodiment relates to signal processing in the signal processing circuit 43, and FIG. 16 is a waveform diagram illustrating the operation thereof. The points indicated by (1) to (7) in FIG. 16 indicate the values obtained by A / D converting the discharge lamp voltage, and the solid line indicates the output of the signal processing circuit 43. For example, assuming that the signal processing in the signal processing circuit 43 is an average of A / D conversion values for the past three times, the signal processing circuit 43 between (3) and (4) The average value of (3) is output. Here, as a countermeasure against noise, a voltage higher by a voltage V1 is set as an upper allowable (range) value than an output voltage Vab of the signal processing circuit 43, and a voltage lower by a voltage V2 is set as a lower allowable (range) value. When the newly obtained signal is outside V1 to V2, it is regarded as a signal including noise and is not used for sampling.
[0085]
  For example, in FIG. 16, when the A / D conversion value of (5) is taken as a value lower than the lower allowable (range) value V2 for the output value immediately before the signal processing circuit 43, it is not used for sampling. . In the sections (4) to (5), the average value of (2), (3), and (4) is output from the signal processing circuit 43, but the data of (5) is a signal lower than Vab−V2. And treat it as noise. As a result, in the section (5) to (6), the previous value, that is, the average value of (2), (3) and (4) is output. Next, in the sections (6) to (7), except for (5), the average values of (3), (4) and (6) are output. By performing such signal processing, operation control that is not affected by noise becomes possible.
[0086]
  Embodiment 23
  In Embodiment 22, when the abnormality detection lower limit value V3 and the abnormality detection upper limit value V4 are set and the A / D conversion value is V3 or less, or V4 or more, the A / D conversion value is not regarded as noise, It is processed as a valid value. When the A / D conversion value is below the abnormality detection lower limit value V3 or above the abnormality detection upper limit value V4, it is considered that the discharge lamp 1 is short-circuited, disconnected, or extinguished, and is not averaged. The output from the signal processing circuit 43 is used as it is.
[0087]
  In FIG. 16, although the A / D conversion value of (7) is smaller than Vab−V2, it is not regarded as noise, but is regarded as an abnormal signal when it is lower than the abnormality detection lower limit V3, and is output from the signal processing circuit 43 as it is. The Similarly, when the A / D conversion value is equal to or greater than the abnormality detection upper limit value, the signal processing circuit 43 outputs the signal as it is without considering it as an abnormality signal. By performing such signal processing, it is possible to perform quick response control in the event of an abnormality without being affected by noise.
[0088]
  Embodiment 24.
  In the twenty-fourth embodiment, the change control unit 441 weights a part or each of the four types of detection voltages of the discharge lamp voltage, the discharge lamp current, the power supply voltage, and the lighting time, and performs data thinning, etc. The sampling speed of data that requires quick control is increased.
[0089]
  For example, since the output from the lighting time detection means 8 and the output from the power supply voltage detection means 7 do not change suddenly, the number of samplings can be reduced. That is, the discharge lamp voltage and the discharge lamp current important for power control are sampled intensively. For example, the power supply voltage is thinned out so that it is sampled once for every 10 times of sampling of the discharge lamp voltage and discharge lamp current, or once for every 20 times. Thereby, the sampling time of the discharge lamp voltage and the discharge lamp current is made faster to improve the accuracy of power control.
[0090]
【The invention's effect】
  According to the first aspect of the present invention, it is possible to remove noise as much as possible and to perform high-speed processing of discharge lamp control.Further, by weighting each detection signal as an element for monitoring the operation state, that is, by appropriately decimating the capture of the detection signal, the detection signal necessary for high-speed processing can be focused and effectively sampled.
[0091]
  According to the second aspect of the present invention, the operating state of the discharge lamp shifts from the transient state to the stable state immediately after the discharge lamp is turned on and thereafter.,Processing methodThe lawBy changing, noise removal and high-speed processing can be realized in each operation state.
[0092]
  According to the third aspect of the present invention, it is possible to reliably detect a rapid decrease in voltage and a rapid increase in discharge current associated with the start of discharge, and accurately and smoothly shift to drive control after the start of discharge.
[0093]
  According to the fourth aspect of the present invention, an alternative value is adopted as the discharge lamp current immediately after the start of discharge so as not to be affected by noise such as an inrush current generated immediately after the start of discharge. Stability immediately after lighting can be ensured, and high-speed processing is possible.
[0094]
  According to the fifth aspect of the present invention, when the light is extinguished due to some influence while the lighting is continued, the captured data is directly processed by the data processing unit, so that high-speed processing for returning to relighting is possible.
[0095]
  Claim6According to the described invention, according to the level of the discharge lamp voltage, that is, according to the magnitude of unnecessary radiation noise, the number of samplings is decreased as the discharge lamp voltage is higher, and is increased as the discharge lamp voltage is lower. Therefore, the influence of noise can be removed uniformly regardless of the level of the discharge lamp voltage after lighting.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of a discharge lamp lighting device according to the present invention.
FIG. 2 is a flowchart for explaining the operation of the first embodiment.
FIG. 3 is a flowchart for explaining the operation of the second embodiment.
FIG. 4 is a flowchart for explaining the operation of the third embodiment.
FIG. 5 is a flowchart for explaining the operation of the fourth embodiment.
FIG. 6 is a flowchart for explaining the operation of the fifth embodiment.
FIG. 7 is a flowchart for explaining the operation of the sixth embodiment.
FIG. 8 is a flowchart for explaining the operation of the seventh embodiment.
FIG. 9 is a flowchart for explaining the operation of the eighth embodiment.
FIG. 10 is a flowchart for explaining the operation of the eighth embodiment.
FIG. 11 is an overall configuration diagram showing another circuit configuration of the discharge lamp lighting device according to the present invention.
FIG. 12 is a circuit diagram showing an example of lighting time detection means.
13 is an overall configuration diagram of a discharge lamp lighting device obtained by adding a timer 45 to the discharge lamp lighting device of FIG. 11 in Embodiment 15. FIG.
14A and 14B are timing charts of detection waveforms, in which FIG. 14A shows a discharge lamp voltage waveform, FIG. 14B shows a discharge lamp current waveform, and FIG. 14C shows A / D conversion timing;
FIG. 15 is a timing chart of detection waveforms, where (a) is a discharge lamp voltage waveform, (b) is a discharge lamp current waveform, and (c) is a diagram showing A / D conversion timing.
FIG. 16 is a waveform diagram illustrating the operation of signal processing in the signal processing circuit.
[Explanation of symbols]
  1 Discharge lamp
  2 Discharge lamp lighting circuit
  3 Power supply
  4 Control circuit block
  41 Multiplexer
  42 A / D converter
  43 Signal processor
  44 Calculation unit
  441 Change control unit
  45 timer
  5 Discharge lamp voltage detector
  6 Discharge lamp current detector
  7 Power supply voltage detector
  8 Lighting time detector
  81 capacitors

Claims (6)

A plurality of detecting means for detecting a plurality of elements related to the operating state of the discharge lamp controlled to be turned on by the discharge lamp lighting circuit; and a taking-in means for converting the detection signal from each detecting means into digital detection data and taking it in , A signal processing means for performing a process of passing through the detected detection data or a process of obtaining calculation data by averaging, and an output supplied to the discharge lamp from the discharge lamp lighting circuit from the calculation data Calculation means for obtaining control data to be controlled; and change control means for changing at least one of the detection signal capture operation in the capture means and the processing method in the signal processing means in accordance with the operating state of the discharge lamp; wherein the change control means, as the change in the incorporation operation of the detection signal in the capturing means in accordance with the operating state of the discharge lamp, the operation of the discharge lamp The discharge lamp lighting apparatus characterized by comprising that those are weighted set according to the type of the detection signal acquisition count from the capturing means in accordance with the state. The change control means, wherein in the after lighting of the discharge lamp then the discharge lamp lighting apparatus according to claim 1, wherein changing the process how the pre SL signal processing means.   2. The discharge lamp lighting device according to claim 1, wherein the change control unit uses the data acquired by the capturing unit as the calculation data before the discharge lamp is turned on.   The storage means which stores beforehand the alternative value corresponding to the detection data immediately after lighting is provided, The said change control means supplies the alternative value from the said storage means to the said calculating means immediately after lighting of the said discharge lamp. Discharge lamp lighting device.   3. The discharge lamp lighting device according to claim 2, wherein when the change control unit is turned off after the discharge lamp is turned on, the captured data in the capture unit is used as the calculation data. The change control unit, a discharge lamp lighting apparatus according to claim 1, wherein the change to the uptake count for the capturing means in accordance with the discharge lamp voltage detected by said detection means.

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