WO2010021191A1 - Discharge tube lighting device - Google Patents

Discharge tube lighting device Download PDF

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Publication number
WO2010021191A1
WO2010021191A1 PCT/JP2009/060733 JP2009060733W WO2010021191A1 WO 2010021191 A1 WO2010021191 A1 WO 2010021191A1 JP 2009060733 W JP2009060733 W JP 2009060733W WO 2010021191 A1 WO2010021191 A1 WO 2010021191A1
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Prior art keywords
frequency
voltage
circuit
discharge tube
signal
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PCT/JP2009/060733
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French (fr)
Japanese (ja)
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中野謙治
荒井繁
渡部聡一
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株式会社村田製作所
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Priority to JP2010525631A priority Critical patent/JP5035422B2/en
Publication of WO2010021191A1 publication Critical patent/WO2010021191A1/en

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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
    • H05B41/14—Circuit arrangements
    • H05B41/26—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc
    • H05B41/28—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters
    • H05B41/282—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters with semiconductor devices
    • H05B41/2825—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters with semiconductor devices by means of a bridge converter in the final stage
    • H05B41/2827—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters with semiconductor devices by means of a bridge converter in the final stage using specially adapted components in the load circuit, e.g. feed-back transformers, piezoelectric transformers; using specially adapted load circuit configurations
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Definitions

  • the present invention relates to a lighting device for a discharge tube such as a cold cathode tube for a backlight of a liquid crystal display.
  • Cold cathode tubes are used for backlights of liquid crystal displays.
  • the cold cathode tube is lit with an alternating voltage of several hundred volts because of its lamp characteristics, and the light emission luminance is determined by the tube current. Therefore, the tube current is controlled by controlling the voltage applied to the cold cathode tube, thereby adjusting the luminance.
  • burst control has been adopted for dimming control in the conventional cold cathode tube lighting device.
  • the drive circuit of the cold cathode tube inverter constitutes an inverter circuit that generates an alternating voltage from a direct current input voltage
  • the conventional lighting device such as a dimmable cold cathode tube drives the inverter intermittently. Is. This makes it possible to perform dimming control while reducing the average value of the tube current while maintaining the applied voltage to the cold cathode tube at the required voltage, and preventing the light from being turned off.
  • intermittent drive control has a low frequency band of several tens to several hundreds of Hz, and in some cases, the screen of the liquid crystal display flickers or audible sound is generated from the transformer. was there.
  • Patent Document 1 discloses a technique for reducing the peak of the noise level by changing the intermittent drive frequency itself of the intermittent drive control.
  • FIG. 1 is a circuit diagram showing a configuration of a lighting device of Patent Document 1
  • FIG. 2 is a waveform diagram of a voltage applied to a cold cathode tube.
  • This lighting device includes an inverter circuit 1, a lighting tube 2, a variable DC voltage supply means 3, an input power supply 4, a DC pulse voltage supply means 7, and an OR circuit 8.
  • a variable DC voltage supply means 3 and a DC pulse voltage supply means 7 are provided in parallel between the input power supply 4 and the OR circuit 8. Further, the output of the OR circuit 8 is configured to be input to the inverter circuit 1. With this configuration, the applied voltage is switched between the period T1 and the period T2 shown in FIG.
  • an object of the present invention is to provide a discharge tube lighting device that suppresses the generation of audible sound and reduces power consumption while avoiding the problem of flickering of light emission luminance when performing dimming control by intermittent drive. It is in.
  • the present invention is configured as follows.
  • a discharge tube lighting device comprising intermittent driving means for performing light control by intermittent driving at a frequency of 2, During the off period of the drive voltage at the second frequency by the intermittent drive of the intermittent drive means, the first frequency at a third frequency lower than the first frequency and higher than the second frequency.
  • An auxiliary intermittent driving means for intermittently driving an AC voltage is provided.
  • the AC voltage of the first frequency is inserted for a very short time based on the third frequency, and vibration due to the intermittent drive is reduced in a short ON period. Since it is diffused by the vibration of another period that occurs, the spectrum of vibration is spread and noise is reduced.
  • auxiliary intermittent drive frequency control means for controlling the variation of the third frequency is provided.
  • dimming is performed by intermittent driving of the applied voltage to the discharge tube at the second frequency, and the vibration by the intermittent driving is diffused by the vibration by the driving at the third frequency, so that the vibration spectrum is It is diffused and noise is reduced. Moreover, since the discharge tube is always driven intermittently, an increase in power consumption can be suppressed.
  • FIG. 5 is a waveform diagram of signals S1 to S4 in FIG. It is a specific circuit diagram of the discharge tube lighting device 101 according to the second embodiment.
  • FIG. 3 is a block diagram showing the configuration of the discharge tube lighting device 100.
  • the discharge tube lighting device 100 includes a drive circuit 21 that drives the high-voltage transformer 22 and the discharge tube 23 based on an input voltage, an output current detection circuit 24 that detects an output current flowing through the discharge tube 23, and the output current detection circuit 24. And an inverter control circuit 25 for driving the drive circuit 21 based on the signal from the dimming signal generation circuit 10 in accordance with the detection signal.
  • the dimming signal generation circuit 10 includes a dimming burst control circuit 12 that generates a rectangular wave signal according to a voltage generated by the dimming voltage generation circuit 11 and a logic circuit 13 that generates a control signal for the inverter control circuit 25 from the signal. It has.
  • the inverter control circuit 25 controls the drive circuit 21 so that an AC voltage is applied to the high-voltage transformer 22 and the discharge tube 23, and the dimming signal generation circuit 10 intermittently drives the inverter control circuit 25. Dimming by
  • FIG. 4 is a specific circuit diagram of the discharge tube lighting device 100 shown in FIG.
  • the drive circuit 21 includes two transistors Q1 and Q2 and capacitors C1 and C2 connected in series between a power supply terminal to which an input voltage is input and the ground.
  • the primary windings of a plurality of high-voltage transformers 22a, 22b,... 22n are connected in parallel to the connection point of Q1, Q2 and the connection point of C1, C2.
  • the secondary windings of these high-voltage transformers 22a, 22b... 22n are connected to discharge tubes 23a, 23b.
  • output current detection circuits 24a, 24b... 24n are connected to these current paths.
  • the inverter control circuit 25 complementarily turns on / off the transistors Q1 and Q2 of the drive circuit 21 at the first frequency f1.
  • the inverter control circuit 25 corresponds to “AC voltage generating means” according to the present invention.
  • the inverter control circuit 25 intermittently controls the on / off of the transistors Q1 and Q2 in accordance with the logic level of the signal from the dimming signal generation circuit 10.
  • the output current detection circuit 24 detects the peak current value of the tube current flowing through the discharge tubes 23a, 23b,.
  • the inverter control circuit 25 performs feedback control by adjusting the on-duty ratios of the transistors Q1 and Q2 in order to stabilize the peak current value of the tube current detected by the output current detection circuit 24.
  • the triangular wave generation circuit 12b In the dimming signal generation circuit 10, the triangular wave generation circuit 12b generates a triangular wave signal of the second frequency f2 that intermittently drives the driving at the first frequency f1.
  • the dimming voltage generation circuit 11 generates a DC dimming voltage according to the user's operation.
  • the comparator 12d compares the output voltage of the dimming voltage generation circuit 11 with the output signal of the triangular wave generation circuit 12b, and generates a rectangular wave signal S2 that is PWM-modulated according to the dimming voltage.
  • the dimming voltage generation circuit 11, the triangular wave generation circuit 12b, and the comparator 12d correspond to the “intermittent drive means” according to the present invention.
  • the rectangular wave generation circuit 12c generates a rectangular wave signal S3 having a third frequency f3 lower than the first frequency f1 and higher than the second frequency f2.
  • the logic circuit 13 is a circuit that outputs a logical sum signal S4 of the signals S2 and S3.
  • FIG. 5 is a waveform diagram of the above signals.
  • the signal S1 is a signal of frequency f1 due to self-oscillation of the inverter control circuit 25, and S2, S3, S4 are signals of each part of the dimming signal generation circuit 10.
  • Dimming of the discharge tube 23 is performed by the dimming voltage generated by the dimming voltage generation circuit 11. That is, the frequency f2 of the signal S2 is constant according to the dimming voltage, but the on-duty ratio changes and the on-period Ton changes. As a result, the average value of the tube current flowing through the discharge tube 23 changes, thereby controlling the light emission luminance.
  • the frequency f1 of the signal S1 is about 20 to 50 kHz, and the frequency f2 of the signal S2 is about 60 to 300 Hz.
  • the frequency f3 of the signal S3 is about 2 to 20 times the frequency f2. Therefore, the auxiliary intermittent driving is performed at least once in the OFF period Toff of the signal S2 (“missing period of intermittent driving”).
  • the rectangular wave generating circuit 12c and the logic circuit 13 correspond to the “auxiliary intermittent driving means” according to the present invention.
  • the inverter is intermittently driven in the repetition period of the signal S3 even in the off period Toff of the signal S2, the vibration due to the frequency f2 is diffused, the spectrum of the vibration is diffused, and the audible noise is reduced. Even if auxiliary intermittent driving is performed, the period during which the tube current flows is not particularly long, and an increase in power consumption can be suppressed.
  • a half-bridge type inverter circuit is configured.
  • other circuit configurations such as a full-bridge type and a push-pull type can be similarly applied.
  • the high voltage transformer 22 may be a non-insulated type as long as the side that supplies the input power supply voltage is insulated from the commercial power supply.
  • a rectangular wave signal is generated by a circuit, and a signal that finally determines the on / off timing of the transistors Q1 and Q2 of the drive circuit 21 is generated by a logic circuit.
  • an on / off timing signal for the transistors Q1 and Q2 of the drive circuit 21 may be generated by program processing.
  • FIG. 6 shows a circuit of a discharge tube lighting device according to the second embodiment.
  • the first embodiment is different from the circuit shown in FIG. 4 in that the rectangular wave generating circuit 12c is a circuit in which the frequency generated by a modulation signal given from the outside changes, and the rectangular wave generating circuit 12c is modulated.
  • a modulation circuit 14 for supplying a signal is provided.
  • the modulation circuit 14 is a circuit that generates a sine wave signal or a triangular wave signal having a frequency lower than the frequency f3 of the signal S3 as a modulation signal.
  • the rectangular wave generating circuit 12c modulates the frequency of the rectangular wave in the frequency range of ⁇ ⁇ f with f3 as the center, according to the modulation signal.
  • the modulation circuit 14, the rectangular wave generation circuit 12c, and the logic circuit 13 correspond to “auxiliary intermittent drive frequency control means” according to the present invention.

Abstract

An inverter control circuit (25) subjects transistors (Q1), (Q2) of a drive circuit (21) to complementary on/off operation.  The inverter control circuit (25) generates a rectangular wave signal S1 of an on/off frequency (a first frequency f1) of the transistors (Q1), (Q2) by self-oscillation.  A triangular wave generation circuit (12b) in a light-control signal generation circuit (10) generates a triangular wave signal of a second frequency f2 for making driving by the first frequency f1 intermittent.  A comparator (12d) compares an output voltage of a light-control voltage generation circuit (11) with an output signal of the triangular wave generation circuit (12b) and generates a rectangular wave signal S2 PWN-modulated according to a light-control voltage.  A rectangular wave generation circuit (12c) generates a rectangular wave signal S3 so as to attain auxiliary intermittent driving by a third frequency f3 lower than the first frequency f1 and higher than the second frequency f2.

Description

放電管点灯装置Discharge tube lighting device
　この発明は、液晶ディスプレイのバックライト用冷陰極管等の放電管の点灯装置に関するものである。 The present invention relates to a lighting device for a discharge tube such as a cold cathode tube for a backlight of a liquid crystal display.
　液晶ディスプレイのバックライト等に冷陰極管が用いられている。冷陰極管は、そのランプ特性から、数百Ｖの交流電圧で点灯し、その発光輝度は管電流によって決まる。そのため、冷陰極管への印加電圧制御により管電流が制御され、これによって輝度が調整される。 Cold cathode tubes are used for backlights of liquid crystal displays. The cold cathode tube is lit with an alternating voltage of several hundred volts because of its lamp characteristics, and the light emission luminance is determined by the tube current. Therefore, the tube current is controlled by controlling the voltage applied to the cold cathode tube, thereby adjusting the luminance.
　しかし、冷陰極管の点灯後、輝度を低減するために印加電圧を下げるとしても、アーク放電を維持するための電圧値を下回ると放電状態を維持できず消灯してしまう。そこで従来の冷陰極管点灯装置における調光制御にはバースト制御と呼ばれる間欠駆動方式が採用されてきた。 However, even if the applied voltage is lowered to reduce the brightness after the cold cathode tube is turned on, the discharge state cannot be maintained and the light is turned off if the voltage value is lower than the voltage for maintaining the arc discharge. Therefore, an intermittent driving method called burst control has been adopted for dimming control in the conventional cold cathode tube lighting device.
　冷陰極管インバータのドライブ回路は、直流入力電圧から交流電圧を生成するインバータ回路を構成しているので、従来の調光可能な冷陰極管等の点灯装置は、上記インバータを間欠的に駆動するものである。このことによって、冷陰極管への印加電圧を必要電圧に維持したまま管電流の平均値を小さくして、消灯を防ぎつつ、調光制御が行える。 Since the drive circuit of the cold cathode tube inverter constitutes an inverter circuit that generates an alternating voltage from a direct current input voltage, the conventional lighting device such as a dimmable cold cathode tube drives the inverter intermittently. Is. This makes it possible to perform dimming control while reducing the average value of the tube current while maintaining the applied voltage to the cold cathode tube at the required voltage, and preventing the light from being turned off.
　しかしながら、間欠駆動制御は、その間欠駆動周波数が数十～数百Ｈｚ程度の低い周波数帯になるため、場合によっては液晶ディスプレイの画面がちらついて見えたり、トランスから可聴音が発生したりする問題があった。 However, intermittent drive control has a low frequency band of several tens to several hundreds of Hz, and in some cases, the screen of the liquid crystal display flickers or audible sound is generated from the transformer. was there.
　この問題を抑制するものとして、本来なら間欠の「欠」となる期間に、冷陰極管の点灯電圧より低い電圧が出るように駆動周波数を制御する（したがって実質的には間欠発振ではない）点灯装置が特許文献１に開示されている。また、間欠駆動制御の間欠駆動周波数自体を変動させることで雑音レベルのピークを下げるものが特許文献２に開示されている。 In order to suppress this problem, the driving frequency is controlled so that a voltage lower than the lighting voltage of the cold-cathode tube is emitted during a period of “intermittent” that is normally intermittent (and therefore, it is not substantially intermittent oscillation). An apparatus is disclosed in Patent Document 1. Patent Document 2 discloses a technique for reducing the peak of the noise level by changing the intermittent drive frequency itself of the intermittent drive control.
　図１は特許文献１の点灯装置の構成を示す回路図、図２は冷陰極管に対する印加電圧の波形図である。この点灯装置は、インバータ回路１、点灯管２、可変直流電圧供給手段３、入力電源４の他、直流パルス電圧供給手段７、ＯＲ回路８を備えている。入力電源４とＯＲ回路８との間に、可変直流電圧供給手段３と直流パルス電圧供給手段７とが並列に設けられている。またＯＲ回路８の出力がインバータ回路１に入力されるように構成されている。この構成により、図２に示したＴ１の期間とＴ２の期間で印加電圧が切り替えられる。 FIG. 1 is a circuit diagram showing a configuration of a lighting device of Patent Document 1, and FIG. 2 is a waveform diagram of a voltage applied to a cold cathode tube. This lighting device includes an inverter circuit 1, a lighting tube 2, a variable DC voltage supply means 3, an input power supply 4, a DC pulse voltage supply means 7, and an OR circuit 8. A variable DC voltage supply means 3 and a DC pulse voltage supply means 7 are provided in parallel between the input power supply 4 and the OR circuit 8. Further, the output of the OR circuit 8 is configured to be input to the inverter circuit 1. With this configuration, the applied voltage is switched between the period T1 and the period T2 shown in FIG.
特開平１１－８７０８５号公報Japanese Patent Laid-Open No. 11-87085 特開２０００－１２３９９４号公報JP 2000-123994 A
　ところが、特許文献１，２に示されている点灯装置ではトランスを常時駆動しているので、輝度あたりの電力消費が大きい。また特許文献２では、間欠駆動周波数が変動するので、液晶ディスプレイのバックライトに用いた場合に、画面のチラツキが日立つという問題があった。
　上述の問題は冷陰極管に限らず、放電管一般に当てはまることである。 However, in the lighting devices shown in Patent Documents 1 and 2, since the transformer is always driven, power consumption per luminance is large. Further, in Patent Document 2, since the intermittent drive frequency fluctuates, there is a problem that the screen flickers when used for a backlight of a liquid crystal display.
The above-mentioned problems are not limited to cold cathode tubes but apply to discharge tubes in general.
　そこで、この発明の目的は、間欠駆動による調光制御を行う際に、発光輝度のチラツキの問題を回避しつつ可聴音の発生を抑え、また電力消費を抑えた放電管点灯装置を提供することにある。 Accordingly, an object of the present invention is to provide a discharge tube lighting device that suppresses the generation of audible sound and reduces power consumption while avoiding the problem of flickering of light emission luminance when performing dimming control by intermittent drive. It is in.
　前記課題を解決するために、この発明は次のように構成する。
（１）直流電圧を第１の周波数の交流電圧に変換して放電管へ印加する駆動電圧を発生する交流電圧発生手段と、前記第１の周波数の交流電圧を前記第１の周波数より低い第２の周波数で間欠駆動することにより調光を行う間欠駆動手段と、を備えた放電管点灯装置において、
　前記間欠駆動手段の前記間欠駆動による前記第２の周波数での前記駆動電圧のオフ期間中に、前記第１の周波数より低く前記第２の周波数より高い第３の周波数で前記第１の周波数の交流電圧を間欠駆動する補助間欠駆動手段を設けたことを特徴とする。 In order to solve the above problems, the present invention is configured as follows.
(1) AC voltage generating means for converting a DC voltage into an AC voltage having a first frequency and generating a driving voltage applied to the discharge tube; and an AC voltage having the first frequency lower than the first frequency. In a discharge tube lighting device comprising intermittent driving means for performing light control by intermittent driving at a frequency of 2,
During the off period of the drive voltage at the second frequency by the intermittent drive of the intermittent drive means, the first frequency at a third frequency lower than the first frequency and higher than the second frequency. An auxiliary intermittent driving means for intermittently driving an AC voltage is provided.
　この構成により、間欠駆動周期の「欠」期間にも、第１の周波数の交流電圧が第３の周波数に基づいて極短時間挿入されることになり、間欠駆動による振動が、短いオン期間で発生する別周期の振動によって拡散されるので、振動のスペクトラムが拡散され、騒音が低減される。 With this configuration, even during the “missing” period of the intermittent drive cycle, the AC voltage of the first frequency is inserted for a very short time based on the third frequency, and vibration due to the intermittent drive is reduced in a short ON period. Since it is diffused by the vibration of another period that occurs, the spectrum of vibration is spread and noise is reduced.
（２）また、前記第３の周波数を変動制御する補助間欠駆動周波数制御手段を備える。
　これにより、上記短いオン期間によって発生する振動の周期性をランダムにでき、間欠駆動周期による振動のスペクトラム拡散効果がより大きくなり、騒音低減効果が大きくなる。 (2) In addition, auxiliary intermittent drive frequency control means for controlling the variation of the third frequency is provided.
Thereby, the periodicity of the vibration generated by the short ON period can be made random, the spectrum spread effect of the vibration due to the intermittent drive period is further increased, and the noise reduction effect is increased.
（３）また、前記第３の周波数でオン／オフ駆動される前記第１の周波数の交流電圧の波は、前記第２の周波数でのオフ期間中に複数波存在するものとする。
　これにより、間欠駆動周期による振動のスペクトラム拡散効果がより大きくなり、騒音低減効果が大きくなる。 (3) In addition, it is assumed that a plurality of AC voltage waves of the first frequency that are driven on / off at the third frequency exist during an off period at the second frequency.
As a result, the spread spectrum effect of vibration due to the intermittent drive cycle is further increased, and the noise reduction effect is increased.
　この発明によれば、放電管に対する印加電圧の第２の周波数での間欠駆動により調光がなされ、その間欠駆動による振動が第３の周波数での駆動による振動で拡散されて、振動のスペクトラムが拡散され、騒音が低減される。また、放電管は常に間欠駆動されるので、電力消費の増大を抑制できる。 According to the present invention, dimming is performed by intermittent driving of the applied voltage to the discharge tube at the second frequency, and the vibration by the intermittent driving is diffused by the vibration by the driving at the third frequency, so that the vibration spectrum is It is diffused and noise is reduced. Moreover, since the discharge tube is always driven intermittently, an increase in power consumption can be suppressed.
特許文献１の点灯装置の構成を示す回路図である。It is a circuit diagram which shows the structure of the lighting device of patent document 1. FIG. 放電管に対する印加電圧の波形図である。It is a wave form diagram of the applied voltage with respect to a discharge tube. 第１の実施形態に係る放電管点灯装置１００の構成を示すブロック図である。It is a block diagram which shows the structure of the discharge tube lighting device 100 which concerns on 1st Embodiment. 第１の実施形態に係る放電管点灯装置１００の具体的な回路図である。It is a specific circuit diagram of the discharge tube lighting device 100 according to the first embodiment. 図４中の信号Ｓ１～Ｓ４の波形図である。FIG. 5 is a waveform diagram of signals S1 to S4 in FIG. 第２の実施形態に係る放電管点灯装置１０１の具体的な回路図である。It is a specific circuit diagram of the discharge tube lighting device 101 according to the second embodiment.
《第１の実施形態》
　この発明の第１の実施形態に係る放電管点灯装置を図３～図５を参照して説明する。
　図３はその放電管点灯装置１００の構成を示すブロック図である。この放電管点灯装置１００は、入力電圧を基にして高圧トランス２２及び放電管２３を駆動する駆動回路２１、放電管２３に流れる出力電流を検出する出力電流検出回路２４、この出力電流検出回路２４による検出信号に応じて、また調光信号発生回路１０からの信号を基にして、駆動回路２１を駆動するインバータ制御回路２５を備えている。 << First Embodiment >>
A discharge tube lighting device according to a first embodiment of the present invention will be described with reference to FIGS.
FIG. 3 is a block diagram showing the configuration of the discharge tube lighting device 100. The discharge tube lighting device 100 includes a drive circuit 21 that drives the high-voltage transformer 22 and the discharge tube 23 based on an input voltage, an output current detection circuit 24 that detects an output current flowing through the discharge tube 23, and the output current detection circuit 24. And an inverter control circuit 25 for driving the drive circuit 21 based on the signal from the dimming signal generation circuit 10 in accordance with the detection signal.
　調光信号発生回路１０は、調光電圧発生回路１１が発生する電圧に応じて矩形波信号を発生する調光バースト制御回路１２及びその信号からインバータ制御回路２５に対する制御信号を発生する論理回路１３を備えている。 The dimming signal generation circuit 10 includes a dimming burst control circuit 12 that generates a rectangular wave signal according to a voltage generated by the dimming voltage generation circuit 11 and a logic circuit 13 that generates a control signal for the inverter control circuit 25 from the signal. It has.
　図３において、インバータ制御回路２５は、高圧トランス２２及び放電管２３に対して交流電圧が印加されるように駆動回路２１を制御し、調光信号発生回路１０がインバータ制御回路２５を間欠駆動することによって調光を行う。 In FIG. 3, the inverter control circuit 25 controls the drive circuit 21 so that an AC voltage is applied to the high-voltage transformer 22 and the discharge tube 23, and the dimming signal generation circuit 10 intermittently drives the inverter control circuit 25. Dimming by
　図４は、図３に示した放電管点灯装置１００の具体的な回路図である。駆動回路２１は、入力電圧が入力される電源端子とグランドとの間に直列接続された２つのトランジスタＱ１，Ｑ２及びコンデンサＣ１，Ｃ２を備えている。Ｑ１，Ｑ２の接続点とＣ１，Ｃ２の接続点には複数の高圧トランス２２ａ，２２ｂ・・・２２ｎの１次巻線が並列に接続されている。これらの高圧トランス２２ａ，２２ｂ・・・２２ｎの２次巻線には負荷である放電管２３ａ，２３ｂ・・・２３ｎが接続される。また、それらの電流経路に出力電流検出回路２４ａ，２４ｂ・・・２４ｎが接続されている。 FIG. 4 is a specific circuit diagram of the discharge tube lighting device 100 shown in FIG. The drive circuit 21 includes two transistors Q1 and Q2 and capacitors C1 and C2 connected in series between a power supply terminal to which an input voltage is input and the ground. The primary windings of a plurality of high- voltage transformers 22a, 22b,... 22n are connected in parallel to the connection point of Q1, Q2 and the connection point of C1, C2. The secondary windings of these high- voltage transformers 22a, 22b... 22n are connected to discharge tubes 23a, 23b. Also, output current detection circuits 24a, 24b... 24n are connected to these current paths.
　インバータ制御回路２５は、駆動回路２１のトランジスタＱ１，Ｑ２を第１の周波数ｆ１で相補的にオン／オフする。このインバータ制御回路２５がこの発明に係る「交流電圧発生手段」に相当する。また、インバータ制御回路２５は、調光信号発生回路１０からの信号の論理レベルに応じて、上記トランジスタＱ１，Ｑ２のオン／オフを間欠制御する。 The inverter control circuit 25 complementarily turns on / off the transistors Q1 and Q2 of the drive circuit 21 at the first frequency f1. The inverter control circuit 25 corresponds to “AC voltage generating means” according to the present invention. The inverter control circuit 25 intermittently controls the on / off of the transistors Q1 and Q2 in accordance with the logic level of the signal from the dimming signal generation circuit 10.
　出力電流検出回路２４は、放電管２３ａ，２３ｂ，・・・２３ｎに流れる管電流のピーク電流値を検出する。上記インバータ制御回路２５は、出力電流検出回路２４により検出された管電流のピーク電流値を安定化させるために、トランジスタＱ１，Ｑ２のオンデューティ比を加減することによってフィードバック制御する。 The output current detection circuit 24 detects the peak current value of the tube current flowing through the discharge tubes 23a, 23b,. The inverter control circuit 25 performs feedback control by adjusting the on-duty ratios of the transistors Q1 and Q2 in order to stabilize the peak current value of the tube current detected by the output current detection circuit 24.
　調光信号発生回路１０において、三角波発生回路１２ｂは上記第１の周波数ｆ１による駆動を間欠駆動する第２の周波数ｆ２の三角波信号を発生する。調光電圧発生回路１１は、利用者の操作に応じた直流の調光電圧を発生する。コンパレータ１２ｄはこの調光電圧発生回路１１の出力電圧と三角波発生回路１２ｂの出力信号とを比較して、調光電圧に応じてＰＷＭ変調された矩形波信号Ｓ２を発生する。この調光電圧発生回路１１、三角波発生回路１２ｂ、及びコンパレータ１２ｄがこの発明に係る「間欠駆動手段」に相当する。 In the dimming signal generation circuit 10, the triangular wave generation circuit 12b generates a triangular wave signal of the second frequency f2 that intermittently drives the driving at the first frequency f1. The dimming voltage generation circuit 11 generates a DC dimming voltage according to the user's operation. The comparator 12d compares the output voltage of the dimming voltage generation circuit 11 with the output signal of the triangular wave generation circuit 12b, and generates a rectangular wave signal S2 that is PWM-modulated according to the dimming voltage. The dimming voltage generation circuit 11, the triangular wave generation circuit 12b, and the comparator 12d correspond to the “intermittent drive means” according to the present invention.
　矩形波発生回路１２ｃは、第１の周波数ｆ１より低く、第２の周波数ｆ２より高い第３の周波数ｆ３の矩形波信号Ｓ３を発生する。 The rectangular wave generation circuit 12c generates a rectangular wave signal S3 having a third frequency f3 lower than the first frequency f1 and higher than the second frequency f2.
　論理回路１３は、上記信号Ｓ２，Ｓ３の論理和信号Ｓ４を出力する回路である。 The logic circuit 13 is a circuit that outputs a logical sum signal S4 of the signals S2 and S3.
　図５は上記各信号の波形図である。ここで、信号Ｓ１はインバータ制御回路２５の自励発振による周波数ｆ１の信号、Ｓ２，Ｓ３，Ｓ４は調光信号発生回路１０各部の信号である。放電管２３の調光は調光電圧発生回路１１が発生する調光電圧によって行われる。すなわち調光電圧に応じて信号Ｓ２の周波数ｆ２は一定であるが、そのオンデューティ比が変化してオン期間Ｔｏｎが変化する。これにより、放電管２３に流れる管電流の平均値が変化し、それによって発光輝度が制御される。 FIG. 5 is a waveform diagram of the above signals. Here, the signal S1 is a signal of frequency f1 due to self-oscillation of the inverter control circuit 25, and S2, S3, S4 are signals of each part of the dimming signal generation circuit 10. Dimming of the discharge tube 23 is performed by the dimming voltage generated by the dimming voltage generation circuit 11. That is, the frequency f2 of the signal S2 is constant according to the dimming voltage, but the on-duty ratio changes and the on-period Ton changes. As a result, the average value of the tube current flowing through the discharge tube 23 changes, thereby controlling the light emission luminance.
　信号Ｓ１の周波数ｆ１は２０～５０ｋＨｚ、信号Ｓ２の周波数ｆ２は６０～３００Ｈｚ程度である。また、信号Ｓ３の周波数ｆ３はｆ２の２～２０倍程度の周波数である。したがって、信号Ｓ２のオフ期間Ｔｏｆｆ（間欠駆動の「欠」期間）で１回以上補助間欠駆動がなされることになる。
　上記矩形波発生回路１２ｃ及び論理回路１３がこの発明に係る「補助間欠駆動手段」に相当する。 The frequency f1 of the signal S1 is about 20 to 50 kHz, and the frequency f2 of the signal S2 is about 60 to 300 Hz. The frequency f3 of the signal S3 is about 2 to 20 times the frequency f2. Therefore, the auxiliary intermittent driving is performed at least once in the OFF period Toff of the signal S2 (“missing period of intermittent driving”).
The rectangular wave generating circuit 12c and the logic circuit 13 correspond to the “auxiliary intermittent driving means” according to the present invention.
　なお、図５に示した例では、矩形波信号Ｓ３のオンデューティ比が５０％未満であるので、この信号Ｓ３で補助間欠駆動されても、放電管に流れる管電流の平均値の増加は殆どなく、発光輝度や消費電力の上昇は殆ど無い。 In the example shown in FIG. 5, since the on-duty ratio of the rectangular wave signal S3 is less than 50%, even if auxiliary intermittent driving is performed with this signal S3, the average value of the tube current flowing in the discharge tube is hardly increased. There is almost no increase in light emission brightness or power consumption.
　このように信号Ｓ２のオフ期間Ｔｏｆｆでも信号Ｓ３の繰り返し周期でインバータが間欠駆動されるので、周波数ｆ２による振動が拡散されて振動のスペクトラムが拡散され、聴感上の騒音が低減される。また、補助間欠駆動を行っても管電流の流れる期間が特に長くなることはなく、電力消費の増大は抑えられる。 As described above, since the inverter is intermittently driven in the repetition period of the signal S3 even in the off period Toff of the signal S2, the vibration due to the frequency f2 is diffused, the spectrum of the vibration is diffused, and the audible noise is reduced. Even if auxiliary intermittent driving is performed, the period during which the tube current flows is not particularly long, and an increase in power consumption can be suppressed.
　なお、図４に示した例ではハーフブリッジ型のインバータ回路を構成したが、その他にフルブリッジ型、プッシュプル型等、他の回路構成にも同様に適用できる。また、入力電源電圧を供給する側が商用電源から絶縁されていれば、高圧トランス２２は非絶縁型であってもよい。 In the example shown in FIG. 4, a half-bridge type inverter circuit is configured. However, other circuit configurations such as a full-bridge type and a push-pull type can be similarly applied. Further, the high voltage transformer 22 may be a non-insulated type as long as the side that supplies the input power supply voltage is insulated from the commercial power supply.
　また、図４に示した例では、矩形波信号を回路により発生し、それを論理回路によって、最終的に駆動回路２１のトランジスタＱ１，Ｑ２のオン／オフタイミングを決定する信号を生成するようにしたが、駆動回路２１のトランジスタＱ１，Ｑ２に対するオン／オフタイミング信号をプログラム処理によって発生するように構成してもよい。 In the example shown in FIG. 4, a rectangular wave signal is generated by a circuit, and a signal that finally determines the on / off timing of the transistors Q1 and Q2 of the drive circuit 21 is generated by a logic circuit. However, an on / off timing signal for the transistors Q1 and Q2 of the drive circuit 21 may be generated by program processing.
《第２の実施形態》
　第２の実施形態に係る放電管点灯装置の回路を図６に示す。
　第１の実施形態で図４に示した回路と異なるのは、矩形波発生回路１２ｃが外部から与えられる変調信号によって発生する周波数が変化する回路であることと、この矩形波発生回路１２ｃへ変調信号を与える変調回路１４を備えたことである。 << Second Embodiment >>
FIG. 6 shows a circuit of a discharge tube lighting device according to the second embodiment.
The first embodiment is different from the circuit shown in FIG. 4 in that the rectangular wave generating circuit 12c is a circuit in which the frequency generated by a modulation signal given from the outside changes, and the rectangular wave generating circuit 12c is modulated. A modulation circuit 14 for supplying a signal is provided.
　変調回路１４は、信号Ｓ３の周波数ｆ３より低い周波数の正弦波信号または三角波信号を変調信号として発生する回路である。矩形波発生回路１２ｃは、この変調信号に応じて、ｆ３を中心として±Δｆの周波数範囲で矩形波の周波数を変調する。
　上記変調回路１４、矩形波発生回路１２ｃ及び論理回路１３がこの発明に係る「補助間欠駆動周波数制御手段」に相当する。 The modulation circuit 14 is a circuit that generates a sine wave signal or a triangular wave signal having a frequency lower than the frequency f3 of the signal S3 as a modulation signal. The rectangular wave generating circuit 12c modulates the frequency of the rectangular wave in the frequency range of ± Δf with f3 as the center, according to the modulation signal.
The modulation circuit 14, the rectangular wave generation circuit 12c, and the logic circuit 13 correspond to “auxiliary intermittent drive frequency control means” according to the present invention.
　このことにより、図５に示した信号Ｓ４のＴｏｆｆ期間での補助間欠駆動の回数が変動し、間欠駆動周期による振動のスペクトラム拡散効果がより大きくなり、騒音低減効果が高まる。 As a result, the number of times of auxiliary intermittent driving during the Toff period of the signal S4 shown in FIG. 5 varies, and the spread spectrum effect of vibration due to the intermittent driving period becomes larger, and the noise reduction effect increases.
１０…調光信号発生回路
１１…調光電圧発生回路
１２…調光バースト制御回路
１２ｄ…コンパレータ
１３…論理回路
１４…変調回路
２１…駆動回路
２２…高圧トランス
２２ａ，２２ｂ・・・２２ｎ…高圧トランス
２３…放電管
２３ａ，２３ｂ・・・２３ｎ…放電管
２４…出力電流検出回路
２４ａ，２４ｂ・・・２４ｎ…出力電流検出回路
２５…インバータ制御回路
１００…放電管点灯装置
１０１…放電管点灯装置
Ｃ１，Ｃ２…コンデンサ
Ｑ１，Ｑ２…トランジスタ DESCRIPTION OF SYMBOLS 10 ... Dimming signal generation circuit 11 ... Dimming voltage generation circuit 12 ... Dimming burst control circuit 12d ... Comparator 13 ... Logic circuit ... Modulation circuit 21 ... Drive circuit 22 ... High voltage transformer 22a, 22b ... 22n ... High voltage transformer 23 ... Discharge tube 23a, 23b ... 23n ... Discharge tube 24 ... Output current detection circuit 24a, 24b ... 24n ... Output current detection circuit 25 ... Inverter control circuit 100 ... Discharge tube lighting device 101 ... Discharge tube lighting device C1 , C2 ... capacitors Q1, Q2 ... transistors

Claims (3)

  1. 　直流電圧を第１の周波数の交流電圧に変換して放電管へ印加する駆動電圧を発生する交流電圧発生手段と、前記第１の周波数の交流電圧を前記第１の周波数より低い第２の周波数で間欠駆動することにより調光を行う間欠駆動手段と、を備えた放電管点灯装置において、
    　前記間欠駆動手段の前記間欠駆動による前記第２の周波数での前記駆動電圧のオフ期間中に、前記第１の周波数より低く前記第２の周波数より高い第３の周波数で前記第１の周波数の交流電圧を間欠駆動する補助間欠駆動手段を設けたことを特徴とする放電管点灯装置。     AC voltage generating means for generating a drive voltage to be applied to the discharge tube by converting a DC voltage into an AC voltage having a first frequency, and an AC voltage having the first frequency being lower than the first frequency. In the discharge tube lighting device provided with intermittent drive means that performs dimming by intermittently driving,
    During the off period of the drive voltage at the second frequency by the intermittent drive of the intermittent drive means, the first frequency at a third frequency lower than the first frequency and higher than the second frequency. A discharge tube lighting device comprising auxiliary intermittent driving means for intermittently driving an AC voltage.
  2. 　前記第３の周波数を変動制御する補助間欠駆動周波数制御手段を備えた、請求項１に記載の放電管点灯装置。 2. The discharge tube lighting device according to claim 1, further comprising auxiliary intermittent drive frequency control means for performing fluctuation control on the third frequency.
  3. 　前記第３の周波数でオン／オフ駆動される前記第１の周波数の交流電圧の波は、前記第２の周波数でのオフ期間中に複数波存在する、請求項１または２に記載の放電管点灯装置。 3. The discharge tube according to claim 1, wherein a plurality of waves of the alternating-current voltage of the first frequency driven on / off at the third frequency are present during an off period at the second frequency. Lighting device.
PCT/JP2009/060733 2008-08-21 2009-06-12 Discharge tube lighting device WO2010021191A1 (en)

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Citations (3)

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JP2008192341A (en) * 2007-02-01 2008-08-21 Nec Tokin Corp Discharge tube lighting device

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JP3554270B2 (en) * 2000-11-29 2004-08-18 太平洋セメント株式会社 Strobe device
JP4686901B2 (en) * 2001-05-30 2011-05-25 パナソニック株式会社 Backlight dimmer
JP2006286287A (en) * 2005-03-31 2006-10-19 Matsushita Electric Ind Co Ltd Light control method of lighting device, lighting apparatus and liquid crystal display apparatus

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JP2000268992A (en) * 1999-03-19 2000-09-29 Fuji Electric Co Ltd Discharge lamp lighting device
JP2006180577A (en) * 2004-12-20 2006-07-06 Zippy Technology Corp Power supply control method in multiplex modulation mode
JP2008192341A (en) * 2007-02-01 2008-08-21 Nec Tokin Corp Discharge tube lighting device

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