JP5788242B2

JP5788242B2 - LED lighting device and display device having the same

Info

Publication number: JP5788242B2
Application number: JP2011141794A
Authority: JP
Inventors: 柴田　行裕; 行裕柴田; 正夫國分; 岡本　雅之; 雅之岡本
Original assignee: Shindengen Electric Manufacturing Co Ltd; Nihon Funen Co Ltd
Current assignee: Shindengen Electric Manufacturing Co Ltd; Nihon Funen Co Ltd
Priority date: 2011-06-27
Filing date: 2011-06-27
Publication date: 2015-09-30
Anticipated expiration: 2031-06-27
Also published as: JP2013008630A

Description

本発明は、ＬＥＤ点灯装置及びこれを備えた表示装置に関する。 The present invention relates to an LED lighting device and a display device including the same.

従来、歩行者用信号機には、一般的に、点灯素子として白熱電球が用いられている。図５に示すように、この歩行者用信号機２００は、白熱電球２１０と、白熱電球２１０の点灯を制御する信号機制御盤２０とを備える。 Conventionally, incandescent bulbs are generally used as lighting elements in pedestrian traffic lights. As shown in FIG. 5, the pedestrian traffic light 200 includes an incandescent light bulb 210 and a traffic light control panel 20 that controls lighting of the incandescent light bulb 210.

信号機制御盤２０は、交流電源Ｅから供給される交流電圧を白熱電球２１０に伝えるか否かスイッチングする半導体リレーＳＳＲ（ＳｏｌｉｄＳｔａｔｅＲｅｌａｙ）を有する。半導体リレーＳＳＲは、等価回路で表すと、スイッチＳＷ１と、スイッチＳＷ１のオン／オフを制御する制御回路ＣＣと、が入出力端子間に並列接続されている。半導体リレーＳＳＲの制御回路ＣＣは、スイッチＳＷ１のオン／オフに拘らず電流を流す。そのため、半導体リレーＳＳＲは、オフ時に、制御回路ＣＣに起因した抵抗成分（例えば数十ｋΩ）を入出力端子間に等価的に有し、交流電圧を完全に遮断することはできない。白熱電球２１０は、半導体リレーＳＳＲのオフ時の抵抗成分を介して電圧及び電流が加えられても点灯しない特性を有している。 The traffic light control panel 20 includes a semiconductor relay SSR (Solid State Relay) that switches whether to transmit the AC voltage supplied from the AC power source E to the incandescent bulb 210. When the semiconductor relay SSR is represented by an equivalent circuit, a switch SW1 and a control circuit CC that controls on / off of the switch SW1 are connected in parallel between input and output terminals. The control circuit CC of the semiconductor relay SSR allows a current to flow regardless of whether the switch SW1 is on or off. Therefore, the semiconductor relay SSR has a resistance component (for example, several tens of kΩ) due to the control circuit CC equivalently between the input and output terminals when it is off, and cannot completely cut off the AC voltage. The incandescent lamp 210 has a characteristic that it does not light even when a voltage and a current are applied through a resistance component when the semiconductor relay SSR is turned off.

一方、近年、白熱電球に比して低消費電力、高寿命、メンテナンスが容易、且つ、高信頼性という特性を有する発光ダイオード（ＬＥＤ）が注目されている。このような発光ダイオードの優れた特性のため、点灯素子として発光ダイオードを用いた歩行者用信号機が求められている。発光ダイオードを用いた歩行者用信号機として、例えば、特許文献１に記載のものが知られている。 On the other hand, in recent years, attention has been paid to light emitting diodes (LEDs) having characteristics of low power consumption, long life, easy maintenance, and high reliability as compared with incandescent bulbs. Because of such excellent characteristics of the light emitting diode, a pedestrian traffic light using the light emitting diode as a lighting element is required. As a pedestrian traffic light using a light emitting diode, for example, the one described in Patent Document 1 is known.

特開２０００−２５９９９３号公報JP 2000-259993 A

しかしながら、上記特許文献１に記載の発光ダイオードを用いた歩行者用信号機と、白熱電球を用いた従来の歩行者用信号機２００とでは、回路構成が大きく異なるため、白熱電球２１０を発光ダイオードに置き換えるには、白熱電球を用いた従来の歩行者用信号機２００全体を交換する必要がある。従って、費用負担が大きくなるという問題がある。 However, the pedestrian traffic light using the light emitting diode described in Patent Document 1 and the conventional pedestrian traffic light 200 using an incandescent light bulb are greatly different in circuit configuration, so the incandescent light bulb 210 is replaced with a light emitting diode. Therefore, it is necessary to replace the entire conventional pedestrian traffic light 200 using an incandescent bulb. Therefore, there is a problem that the cost burden increases.

そのため、上記白熱電球を用いた従来の歩行者用信号機２００の信号機制御盤２０をそのまま用いて、白熱電球２１０のみを発光ダイオードに交換する技術が考えられる。しかし、前述のように、半導体リレーＳＳＲのスイッチがオフした状態であっても、半導体リレーＳＳＲは抵抗成分を有しているため、発光ダイオードに電圧及び電流が加えられて発光ダイオードが点灯してしまうという問題がある。 Therefore, a technique for replacing only the incandescent light bulb 210 with a light emitting diode using the signal control panel 20 of the conventional pedestrian traffic light 200 using the incandescent light bulb can be considered. However, as described above, even when the switch of the semiconductor relay SSR is in an off state, the semiconductor relay SSR has a resistance component, so that voltage and current are applied to the light emitting diode, and the light emitting diode is turned on. There is a problem of end.

そこで、本発明は、従来の信号機制御盤を用いつつ、半導体リレーのスイッチがオフした状態では発光ダイオードを消灯させることができるＬＥＤ点灯装置及びこれを備えた表示装置を提供することを目的とする。 SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an LED lighting device capable of turning off a light emitting diode when a semiconductor relay switch is turned off while using a conventional traffic light control panel, and a display device having the LED lighting device. .

本発明の一態様に係る実施例に従ったＬＥＤ点灯装置は、
交流電源からの交流電圧が、オン又はオフに切り替えられ且つオフ時に抵抗成分を有するスイッチ部を介して、供給されるＬＥＤ点灯装置であって、
供給された交流電圧を整流して第１端子及び第２端子間から整流電圧を出力する整流素子と、
前記整流電圧が供給されるＬＥＤ素子と、
第１抵抗及び第２抵抗を有し、供給された前記整流電圧に基づいて前記第１端子及び第２端子間の抵抗を切り替える抵抗切り替え部と、を備え、
前記抵抗切り替え部は、前記整流電圧が判定電圧未満の時、前記第１端子及び第２端子間に前記第１抵抗を接続し、これにより前記第１抵抗を前記整流素子を介して前記スイッチ部に電気的に接続し、前記整流電圧が前記判定電圧以上の時、前記第１端子及び第２端子間に、前記第１抵抗に代えて、前記第１抵抗より高抵抗な前記第２抵抗を接続し、これにより前記第２抵抗を前記整流素子を介して前記スイッチ部に電気的に接続し、
前記判定電圧は、前記ＬＥＤ素子が点灯するために必要な電圧未満である
ことを特徴とする。 An LED lighting device according to an embodiment according to one aspect of the present invention,
An LED lighting device in which an AC voltage from an AC power source is switched on or off and supplied via a switch unit having a resistance component when off,
A rectifying element that rectifies the supplied AC voltage and outputs a rectified voltage between the first terminal and the second terminal;
An LED element to which the rectified voltage is supplied;
A resistance switching unit that includes a first resistor and a second resistor, and switches a resistance between the first terminal and the second terminal based on the supplied rectified voltage;
The resistance switching unit is configured to connect the first resistor between the first terminal and the second terminal when the rectified voltage is lower than a determination voltage, and thereby connect the first resistor to the switch unit via the rectifying element. When the rectified voltage is equal to or higher than the determination voltage, the second resistor having a higher resistance than the first resistor is provided between the first terminal and the second terminal instead of the first resistor. And thereby electrically connecting the second resistor to the switch part via the rectifying element,
The determination voltage is less than a voltage necessary for the LED element to light up.

上記ＬＥＤ点灯装置において、
前記スイッチ部がオフ時に、前記整流電圧は、前記スイッチ部の前記抵抗成分と前記第１抵抗とによって前記判定電圧未満に降圧されても良い。 In the LED lighting device,
When the switch unit is off, the rectified voltage may be stepped down below the determination voltage by the resistance component of the switch unit and the first resistor.

上記ＬＥＤ点灯装置において、
前記第１抵抗は、前記スイッチ部の前記抵抗成分より低抵抗であっても良い。 In the LED lighting device,
The first resistor may have a lower resistance than the resistance component of the switch unit.

上記ＬＥＤ点灯装置において、
前記抵抗切り替え部は、
前記第１端子に一端が接続され、前記整流電圧が前記判定電圧以上の時に導通する電圧検出素子と、
前記電圧検出素子の他端に制御端子が接続され、前記第２抵抗と前記第２端子との間に一端及び他端が接続され、前記電圧検出素子が導通した時にオンする第１のスイッチング素子と、
前記第１のスイッチング素子の前記一端に制御端子が接続され、前記第１抵抗と前記第２端子との間に一端及び他端が接続され、前記第１のスイッチング素子がオンした時にオフする第２のスイッチング素子と、を有しても良い。 In the LED lighting device,
The resistance switching unit
A voltage detection element having one end connected to the first terminal and conducting when the rectified voltage is equal to or higher than the determination voltage;
A control terminal is connected to the other end of the voltage detection element, one end and the other end are connected between the second resistor and the second terminal, and the first switching element is turned on when the voltage detection element is turned on When,
A control terminal is connected to the one end of the first switching element, one end and the other end are connected between the first resistor and the second terminal, and the first switching element is turned off when the first switching element is turned on. 2 switching elements.

上記ＬＥＤ点灯装置において、
前記ＬＥＤ素子と前記整流素子の前記第２端子との間に接続され、前記ＬＥＤ素子に流れる電流を制御する電流制御部を備えても良い。 In the LED lighting device,
You may provide the electric current control part which is connected between the said LED element and the said 2nd terminal of the said rectifier element, and controls the electric current which flows into the said LED element.

上記ＬＥＤ点灯装置において、
前記電流制御部は、
前記ＬＥＤ素子に一端が接続された電流制御素子と、
前記電流制御素子の他端と前記第２端子との間に接続された第３抵抗と、
前記第１端子に一端が接続された第４抵抗と、
前記第４抵抗の他端に一端が接続され、前記第２端子に他端が接続され、生成した基準電圧を前記一端から前記電流制御素子の制御端子に供給する基準電圧生成素子と、を有しても良い。 In the LED lighting device,
The current controller is
A current control element having one end connected to the LED element;
A third resistor connected between the other end of the current control element and the second terminal;
A fourth resistor having one end connected to the first terminal;
One end connected to the other end of the fourth resistor, the other end connected to the second terminal, and a reference voltage generating element for supplying the generated reference voltage to the control terminal of the current control element from the one end. You may do it.

上記ＬＥＤ点灯装置において、
前記第４抵抗の一端は前記電圧検出素子を介して前記第１端子に接続されていても良い。 In the LED lighting device,
One end of the fourth resistor may be connected to the first terminal via the voltage detection element.

上記ＬＥＤ点灯装置において、
前記電流制御部は、前記ＬＥＤ素子と前記整流素子の前記第２端子との間に接続された電流制御抵抗を有しても良い。 In the LED lighting device,
The current control unit may include a current control resistor connected between the LED element and the second terminal of the rectifying element.

上記ＬＥＤ点灯装置において、
前記ＬＥＤ素子は、直列接続された複数のＬＥＤで構成されていても良い。 In the LED lighting device,
The LED element may be composed of a plurality of LEDs connected in series.

上記ＬＥＤ点灯装置において、
前記電圧検出素子は、ツェナーダイオードであっても良い。 In the LED lighting device,
The voltage detection element may be a Zener diode.

上記ＬＥＤ点灯装置において、
前記基準電圧生成素子は、前記電流制御素子の他端の電圧が一定となるように前記基準電圧を生成するシャントレギュレータであっても良い。 In the LED lighting device,
The reference voltage generation element may be a shunt regulator that generates the reference voltage so that the voltage at the other end of the current control element is constant.

上記ＬＥＤ点灯装置において、
前記第２抵抗の抵抗値は、前記第１抵抗の抵抗値の十倍以上であっても良い。 In the LED lighting device,
The resistance value of the second resistor may be ten times or more the resistance value of the first resistor.

上記ＬＥＤ点灯装置において、
前記抵抗切り替え部は、
前記電圧検出素子の他端と前記第１のスイッチング素子の制御端子との間に接続された第５抵抗を更に有しても良い。 In the LED lighting device,
The resistance switching unit
You may further have the 5th resistance connected between the other end of the said voltage detection element, and the control terminal of the said 1st switching element.

上記ＬＥＤ点灯装置において、
前記第１のスイッチング素子及び前記第２のスイッチング素子は、ＮＰＮトランジスタであっても良い。 In the LED lighting device,
The first switching element and the second switching element may be NPN transistors.

上記ＬＥＤ点灯装置において、
前記電流制御素子は、Ｎ型ＭＯＳトランジスタであっても良い。 In the LED lighting device,
The current control element may be an N-type MOS transistor.

本発明の一態様に係る実施例に従った表示装置は、
交流電源からの交流電圧が供給され、オン又はオフに切り替えられ且つオフ時に抵抗成分を有するスイッチ部と、
前記スイッチ部を介して供給された交流電圧を整流して第１端子及び第２端子間から整流電圧を出力する整流素子と、
前記整流電圧が供給されるＬＥＤ素子と、
第１抵抗及び第２抵抗を有し、供給された前記整流電圧に基づいて前記第１端子及び第２端子間の抵抗を切り替える抵抗切り替え部と、を備え、
前記抵抗切り替え部は、前記整流電圧が判定電圧未満の時、前記第１端子及び第２端子間に前記第１抵抗を接続し、これにより前記第１抵抗を前記整流素子を介して前記スイッチ部に電気的に接続し、前記整流電圧が前記判定電圧以上の時、前記第１端子及び第２端子間に、前記第１抵抗に代えて、前記第１抵抗より高抵抗な前記第２抵抗を接続し、これにより前記第２抵抗を前記整流素子を介して前記スイッチ部に電気的に接続し、
前記判定電圧は、前記ＬＥＤ素子が点灯するために必要な電圧未満である
ことを特徴とする表示装置。 A display device according to an embodiment of one aspect of the present invention includes:
An alternating voltage from an alternating current power source is supplied, switched on or off, and having a resistance component when turned off;
A rectifying element that rectifies an alternating voltage supplied via the switch unit and outputs a rectified voltage between the first terminal and the second terminal;
An LED element to which the rectified voltage is supplied;
A resistance switching unit that includes a first resistor and a second resistor, and switches a resistance between the first terminal and the second terminal based on the supplied rectified voltage;
The resistance switching unit is configured to connect the first resistor between the first terminal and the second terminal when the rectified voltage is lower than a determination voltage, and thereby connect the first resistor to the switch unit via the rectifying element. When the rectified voltage is equal to or higher than the determination voltage, the second resistor having a higher resistance than the first resistor is provided between the first terminal and the second terminal instead of the first resistor. And thereby electrically connecting the second resistor to the switch part via the rectifying element,
The display device, wherein the determination voltage is less than a voltage necessary for the LED element to light.

本発明の一態様に係るＬＥＤ点灯装置によれば、抵抗切り替え部が、整流電圧が判定電圧未満の時、第１抵抗を、整流素子を介してスイッチ部に電気的に接続して、整流電圧が判定電圧以上の時、第１抵抗より高抵抗である第２抵抗を、整流素子を介してスイッチ部に電気的に接続するようにしている。また、上記判定電圧は、ＬＥＤ素子が点灯するために必要な電圧未満になるようにしている。これにより、スイッチ部がオフ時には、整流電圧は、スイッチ部の抵抗成分と第１抵抗とによって降圧されるので、スイッチ部の抵抗成分が存在しても、ＬＥＤ素子を点灯しないようにできる。また、スイッチ部がオン時には、整流電圧が判定電圧以上になると、電流は第１抵抗に流れず高抵抗な第２抵抗に流れる。従って、ＬＥＤ素子の点灯に寄与しない電流が第１抵抗に流れる期間を短縮して、電力損失及び発熱量を低減できる。 According to the LED lighting device of one aspect of the present invention, the resistance switching unit electrically connects the first resistor to the switch unit via the rectifying element when the rectified voltage is less than the determination voltage, Is equal to or higher than the determination voltage, the second resistor having a higher resistance than the first resistor is electrically connected to the switch unit via the rectifying element. The determination voltage is set to be lower than a voltage necessary for the LED element to light. Thereby, when the switch unit is off, the rectified voltage is stepped down by the resistance component of the switch unit and the first resistor, so that the LED element can be prevented from being lit even if the resistance component of the switch unit exists. In addition, when the rectified voltage becomes equal to or higher than the determination voltage when the switch unit is on, current does not flow through the first resistor but flows through the high-resistance second resistor. Therefore, it is possible to shorten the period during which a current that does not contribute to lighting of the LED element flows through the first resistor, thereby reducing power loss and heat generation.

図１は、本発明の実施例１に係るＬＥＤ点灯装置を備える表示装置の回路図である。1 is a circuit diagram of a display device including an LED lighting device according to Embodiment 1 of the present invention. 図２は、比較例に係るＬＥＤ点灯装置を備える表示装置の回路図である。FIG. 2 is a circuit diagram of a display device including an LED lighting device according to a comparative example. 図３は、本発明の実施例１に係るＬＥＤ点灯装置と、比較例に係るＬＥＤ点灯装置と、の電流及び電圧を示す波形図である。FIG. 3 is a waveform diagram showing current and voltage of the LED lighting device according to Example 1 of the present invention and the LED lighting device according to the comparative example. 図４は、本発明の実施例２に係るＬＥＤ点灯装置を備える表示装置の回路図である。FIG. 4 is a circuit diagram of a display device including the LED lighting device according to Embodiment 2 of the present invention. 図５は、従来の歩行者用信号機の回路図である。FIG. 5 is a circuit diagram of a conventional pedestrian traffic light.

以下、本発明に係る各実施例について図面に基づいて説明する。 Embodiments according to the present invention will be described below with reference to the drawings.

図１は、本発明の実施例１に係るＬＥＤ点灯装置１０を備える表示装置の回路図である。表示装置は、ＬＥＤ点灯装置１０と、信号機制御盤（制御部）２０と、を備える。本実施例では、表示装置は、歩行者用信号機を構成しているものとする。 FIG. 1 is a circuit diagram of a display device including an LED lighting device 10 according to Embodiment 1 of the present invention. The display device includes an LED lighting device 10 and a traffic light control panel (control unit) 20. In this embodiment, it is assumed that the display device constitutes a pedestrian traffic light.

信号機制御盤２０は、電源Ｅに直列接続された半導体リレー（スイッチ部）ＳＳＲ（ＳｏｌｉｄＳｔａｔｅＲｅｌａｙ）を有する。半導体リレーＳＳＲは、オン又はオフに切り替えられ且つオフ時に抵抗成分Ｒｓｓｒを有する。即ち、半導体リレーＳＳＲは、等価回路で表すと、スイッチＳＷ１と抵抗成分Ｒｓｓｒとが入出力端子間に並列接続されている。抵抗成分Ｒｓｓｒは、例えば数十ｋΩであり、半導体リレーＳＳＲの形式によって異なる。 The traffic signal control panel 20 includes a semiconductor relay (switch unit) SSR (Solid State Relay) connected in series to the power source E. The semiconductor relay SSR is switched on or off and has a resistance component Rssr when it is off. That is, in the semiconductor relay SSR, when represented by an equivalent circuit, the switch SW1 and the resistance component Rssr are connected in parallel between the input and output terminals. The resistance component Rssr is, for example, several tens of kΩ, and varies depending on the type of the semiconductor relay SSR.

ＬＥＤ点灯装置１０には、交流電源Ｅからの交流電圧が、半導体リレーＳＳＲを介して、供給される。つまり、半導体リレーＳＳＲがオン時には、スイッチＳＷ１が閉じ、交流電源Ｅからの交流電圧がスイッチＳＷ１を介してそのままＬＥＤ点灯装置１０に供給される。半導体リレーＳＳＲがオフ時には、スイッチＳＷ１が開き、交流電源Ｅからの交流電圧が抵抗成分Ｒｓｓｒを介してＬＥＤ点灯装置１０に供給される。 The LED lighting device 10 is supplied with an AC voltage from the AC power source E via the semiconductor relay SSR. That is, when the semiconductor relay SSR is on, the switch SW1 is closed, and the AC voltage from the AC power source E is supplied to the LED lighting device 10 as it is through the switch SW1. When the semiconductor relay SSR is OFF, the switch SW1 is opened, and the AC voltage from the AC power source E is supplied to the LED lighting device 10 via the resistance component Rssr.

ＬＥＤ点灯装置１０は、整流素子Ｂ１と、ＬＥＤ素子１１と、電流制御部１２と、抵抗切り替え部１３と、を備える。 The LED lighting device 10 includes a rectifying element B1, an LED element 11, a current control unit 12, and a resistance switching unit 13.

整流素子Ｂ１は、４つのダイオードで構成されたブリッジダイオードである。整流素子Ｂ１は、交流電源Ｅから半導体リレーＳＳＲを介して供給された交流電圧を全波整流して第１端子Ｔ１及び第２端子Ｔ２間から整流電圧Ｖｒを出力する。 The rectifying element B1 is a bridge diode composed of four diodes. The rectifying element B1 performs full-wave rectification on the AC voltage supplied from the AC power supply E via the semiconductor relay SSR, and outputs the rectified voltage Vr between the first terminal T1 and the second terminal T2.

ＬＥＤ素子１１は、整流素子Ｂ１の第１端子Ｔ１にアノード（一端）が接続され、整流電圧Ｖｒが供給される。本実施例では、ＬＥＤ素子１１は、第１端子Ｔ１と電流制御部１２との間に直列接続された３４個のＬＥＤ（ＬＥＤ１〜ＬＥＤ３４）で構成されている。例えば、１つのＬＥＤの順方向電圧を３Ｖとすると、ＬＥＤ素子１１が点灯するために必要な電圧は、約１００Ｖである。 The LED element 11 has an anode (one end) connected to the first terminal T1 of the rectifying element B1 and is supplied with the rectified voltage Vr. In the present embodiment, the LED element 11 is composed of 34 LEDs (LED1 to LED34) connected in series between the first terminal T1 and the current control unit 12. For example, if the forward voltage of one LED is 3V, the voltage necessary for the LED element 11 to light is about 100V.

電流制御部１２は、ＬＥＤ素子１１のカソード（他端）と整流素子Ｂ１の第２端子Ｔ２との間に接続され、ＬＥＤ素子１１に流れる電流を制御する。 The current control unit 12 is connected between the cathode (the other end) of the LED element 11 and the second terminal T2 of the rectifying element B1, and controls the current flowing through the LED element 11.

抵抗切り替え部１３は、第１抵抗Ｒ１及び第２抵抗Ｒ２を有し、供給された整流電圧Ｖｒに基づいて第１端子Ｔ１及び第２端子Ｔ２間の抵抗を切り替える。第１抵抗Ｒ１は、一端が第１端子Ｔ１に接続され、半導体リレーＳＳＲの抵抗成分Ｒｓｓｒより低抵抗である。第２抵抗Ｒ２は、一端が第１端子Ｔ１に接続され、第１抵抗Ｒ１より高抵抗である。例えば、第２抵抗Ｒ２の抵抗値は、第１抵抗Ｒ１の抵抗値の十倍以上である。本実施例では、第１抵抗Ｒ１は約５ｋΩであり、第２抵抗Ｒ２は約２００ｋΩである。 The resistance switching unit 13 has a first resistor R1 and a second resistor R2, and switches the resistance between the first terminal T1 and the second terminal T2 based on the supplied rectified voltage Vr. One end of the first resistor R1 is connected to the first terminal T1, and has a lower resistance than the resistance component Rssr of the semiconductor relay SSR. One end of the second resistor R2 is connected to the first terminal T1, and has a higher resistance than the first resistor R1. For example, the resistance value of the second resistor R2 is ten times or more the resistance value of the first resistor R1. In the present embodiment, the first resistor R1 is about 5 kΩ, and the second resistor R2 is about 200 kΩ.

具体的には、抵抗切り替え部１３は、整流電圧Ｖｒが判定電圧未満の時、整流素子Ｂ１の第１端子Ｔ１及び第２端子Ｔ２間に第１抵抗Ｒ１を電気的に接続し、これにより第１抵抗Ｒ１を、整流素子Ｂ１を介して半導体リレーＳＳＲに電気的に接続する。よって、半導体リレーＳＳＲがオフ時に、整流電圧Ｖｒは、半導体リレーＳＳＲの抵抗成分Ｒｓｓｒと第１抵抗Ｒ１とによって降圧される。半導体リレーＳＳＲがオフ時に、整流電圧Ｖｒが判定電圧未満になるように、第１抵抗Ｒ１の値が設定されている。従って、半導体リレーＳＳＲがオフ時には、定常的に、第１抵抗Ｒ１が半導体リレーＳＳＲに電気的に接続されるようになっている。上記判定電圧は、ＬＥＤ素子１１が点灯するために必要な電圧未満である。 Specifically, when the rectified voltage Vr is less than the determination voltage, the resistance switching unit 13 electrically connects the first resistor R1 between the first terminal T1 and the second terminal T2 of the rectifier element B1, thereby One resistor R1 is electrically connected to the semiconductor relay SSR via the rectifying element B1. Therefore, when the semiconductor relay SSR is OFF, the rectified voltage Vr is stepped down by the resistance component Rssr and the first resistor R1 of the semiconductor relay SSR. The value of the first resistor R1 is set so that the rectified voltage Vr is less than the determination voltage when the semiconductor relay SSR is off. Therefore, when the semiconductor relay SSR is OFF, the first resistor R1 is electrically connected to the semiconductor relay SSR constantly. The determination voltage is less than a voltage necessary for the LED element 11 to light up.

また、抵抗切り替え部１３は、整流電圧Ｖｒが判定電圧以上の時、整流素子Ｂ１の第１端子Ｔ１及び第２端子Ｔ２間に、第１抵抗Ｒ１に代えて、第２抵抗Ｒ２を電気的に接続し、これにより第２抵抗Ｒ２を、整流素子Ｂ１を介して半導体リレーＳＳＲに電気的に接続する。 The resistance switching unit 13 electrically connects the second resistor R2 between the first terminal T1 and the second terminal T2 of the rectifying element B1 instead of the first resistor R1 when the rectified voltage Vr is equal to or higher than the determination voltage. Thus, the second resistor R2 is electrically connected to the semiconductor relay SSR via the rectifying element B1.

本実施例では、抵抗切り替え部１３は、ツェナーダイオード（電圧検出素子）ＺＤ１と、ＮＰＮトランジスタ（第２のスイッチング素子）Ｑ１と、ＮＰＮトランジスタ（第１のスイッチング素子）Ｑ２と、第５抵抗Ｒ４と、をさらに有する。 In this embodiment, the resistance switching unit 13 includes a Zener diode (voltage detection element) ZD1, an NPN transistor (second switching element) Q1, an NPN transistor (first switching element) Q2, and a fifth resistor R4. And further.

ツェナーダイオードＺＤ１は、第１端子Ｔ１にカソード（一端）が接続され、整流電圧Ｖｒが判定電圧以上の時に導通する。つまり、ツェナーダイオードＺＤ１のツェナー電圧が判定電圧となる。例えば、本実施例では、判定電圧は約３０Ｖである。 The Zener diode ZD1 is electrically connected when the cathode (one end) is connected to the first terminal T1 and the rectified voltage Vr is equal to or higher than the determination voltage. That is, the Zener voltage of the Zener diode ZD1 becomes the determination voltage. For example, in this embodiment, the determination voltage is about 30V.

ＮＰＮトランジスタＱ２は、ツェナーダイオードＺＤ１のアノード（他端）に、電流制限用の第５抵抗Ｒ４を介してベース（制御端子）が接続され、第２抵抗Ｒ２の他端にコレクタ（一端）が接続され、第２端子Ｔ２にエミッタ（他端）が接続されている。これにより、ＮＰＮトランジスタＱ２は、ツェナーダイオードＺＤ１が導通した時に、第５抵抗Ｒ４を介してベースに電流が流れてオンする。 The NPN transistor Q2 has a base (control terminal) connected to the anode (the other end) of the Zener diode ZD1 via a fifth resistor R4 for current limiting, and a collector (one end) connected to the other end of the second resistor R2. The emitter (the other end) is connected to the second terminal T2. As a result, when the Zener diode ZD1 becomes conductive, the NPN transistor Q2 is turned on by current flowing through the fifth resistor R4.

ＮＰＮトランジスタＱ１は、ＮＰＮトランジスタＱ２のコレクタにベース（制御端子）が接続され、第１抵抗Ｒ１の他端にコレクタ（一端）が接続され、第２端子Ｔ２にエミッタ（他端）が接続されている。ＮＰＮトランジスタＱ１は、ＮＰＮトランジスタＱ２がオンした時にオフする。 The NPN transistor Q1 has a base (control terminal) connected to the collector of the NPN transistor Q2, a collector (one end) connected to the other end of the first resistor R1, and an emitter (other end) connected to the second terminal T2. Yes. The NPN transistor Q1 is turned off when the NPN transistor Q2 is turned on.

電流制御部１２は、Ｎ型ＭＯＳトランジスタ（電流制御素子）Ｑ３と、第３抵抗Ｒ５と、第４抵抗Ｒ３と、シャントレギュレータ（基準電圧生成素子）ＩＣ１と、を有する。 The current control unit 12 includes an N-type MOS transistor (current control element) Q3, a third resistor R5, a fourth resistor R3, and a shunt regulator (reference voltage generation element) IC1.

Ｎ型ＭＯＳトランジスタＱ３は、ＬＥＤ素子１１のカソードにドレイン（一端）が接続されている。第３抵抗Ｒ５は、Ｎ型ＭＯＳトランジスタＱ３のソース（他端）と第２端子Ｔ２との間に接続されている。電流制限用の第４抵抗Ｒ３の一端は、ツェナーダイオードＺＤ１を介して第１端子Ｔ１に接続されている。 In the N-type MOS transistor Q3, the drain (one end) is connected to the cathode of the LED element 11. The third resistor R5 is connected between the source (the other end) of the N-type MOS transistor Q3 and the second terminal T2. One end of the current limiting fourth resistor R3 is connected to the first terminal T1 via a Zener diode ZD1.

シャントレギュレータＩＣ１は、第４抵抗Ｒ３の他端にカソード（一端）が接続され、第２端子Ｔ２にアノード（他端）が接続され、Ｎ型ＭＯＳトランジスタＱ３のソースに基準端子が接続されている。シャントレギュレータＩＣ１は、基準端子に供給されたＮ型ＭＯＳトランジスタＱ３のソースの電圧が一定となるように基準電圧を生成し、生成した基準電圧を、カソードからＮ型ＭＯＳトランジスタＱ３のゲート（制御端子）に供給する。Ｎ型ＭＯＳトランジスタＱ３のソースの電圧が一定となるように制御されるので、ＬＥＤ素子１１に流れる電流は、ほぼ一定に制御される。 The shunt regulator IC1 has a cathode (one end) connected to the other end of the fourth resistor R3, an anode (the other end) connected to the second terminal T2, and a reference terminal connected to the source of the N-type MOS transistor Q3. . The shunt regulator IC1 generates a reference voltage so that the source voltage of the N-type MOS transistor Q3 supplied to the reference terminal is constant, and the generated reference voltage is supplied from the cathode to the gate (control terminal) of the N-type MOS transistor Q3. ). Since the source voltage of the N-type MOS transistor Q3 is controlled to be constant, the current flowing through the LED element 11 is controlled to be substantially constant.

次に、発明者らが知得する比較例のＬＥＤ点灯装置１００について説明する。 Next, the LED lighting device 100 of the comparative example that the inventors know will be described.

図２は、比較例に係るＬＥＤ点灯装置１００を備える表示装置の回路図である。このＬＥＤ点灯装置１００においては、第５抵抗Ｒ４の一端が、ツェナーダイオードＺＤ１のアノードに接続される代わりに、Ｎ型ＭＯＳトランジスタＱ３のソースに接続されている点が、実施例１のＬＥＤ点灯装置１０と異なる。これら以外の構成は、図１の実施例１の構成と同一であるため、同一の構成要素に同一の符号を付し、説明を省略する。 FIG. 2 is a circuit diagram of a display device including the LED lighting device 100 according to the comparative example. In this LED lighting device 100, one end of the fifth resistor R4 is connected to the source of the N-type MOS transistor Q3 instead of being connected to the anode of the Zener diode ZD1. Different from 10. Since the configuration other than these is the same as the configuration of the first embodiment shown in FIG. 1, the same components are denoted by the same reference numerals, and description thereof is omitted.

比較例のＬＥＤ点灯装置１００は、ＬＥＤ素子１１に電流が流れたことを検出して、それにより第１抵抗Ｒ１に電流が流れないようにする。 The LED lighting device 100 of the comparative example detects that a current has flowed through the LED element 11, and thereby prevents a current from flowing through the first resistor R1.

次に、実施例１のＬＥＤ点灯装置１０の動作を、比較例のＬＥＤ点灯装置１００の動作と比較して説明する。 Next, operation | movement of the LED lighting device 10 of Example 1 is demonstrated compared with operation | movement of the LED lighting device 100 of a comparative example.

（１）半導体リレーＳＳＲがオフ時
半導体リレーＳＳＲがオフ時、実施例１のＬＥＤ点灯装置１０と、比較例のＬＥＤ点灯装置１００は、共に、第１抵抗Ｒ１に電流を流すように動作する。この時、交流電圧は抵抗成分Ｒｓｓｒを介して供給されるため、整流素子Ｂ１の第１端子Ｔ１及び第２端子Ｔ２間のインピーダンスに応じて、整流電圧Ｖｒは交流電圧より低い電圧となる。 (1) When the semiconductor relay SSR is off When the semiconductor relay SSR is off, the LED lighting device 10 of the first embodiment and the LED lighting device 100 of the comparative example both operate so as to pass a current through the first resistor R1. At this time, since the alternating voltage is supplied via the resistance component Rssr, the rectified voltage Vr is lower than the alternating voltage according to the impedance between the first terminal T1 and the second terminal T2 of the rectifying element B1.

実施例１のＬＥＤ点灯装置１０では、交流電圧の増加に応じて整流電圧Ｖｒが０Ｖから増加した直後、整流電圧Ｖｒは判定電圧未満であるため、ツェナーダイオードＺＤ１は導通しない。従って、ＮＰＮトランジスタＱ２はオフする。一方、整流電圧Ｖｒによって、第２抵抗Ｒ２を介してＮＰＮトランジスタＱ１のベースに電流が流れるので、ＮＰＮトランジスタＱ１がオンする。これにより、オフ状態にある半導体リレーＳＳＲの抵抗成分Ｒｓｓｒと、整流素子Ｂ１と、第１抵抗Ｒ１と、ＮＰＮトランジスタＱ１と、に電流が流れる。従って、交流電源Ｅからの交流電圧は、半導体リレーＳＳＲの抵抗成分Ｒｓｓｒと第１抵抗Ｒ１とによって分圧される。得られた整流電圧Ｖｒは、前述のように、判定電圧未満に降圧されている。よって、交流電圧が最大となってもＬＥＤ素子１１に電流が流れることは無いため、ＬＥＤ素子１１は点灯しない。 In the LED lighting device 10 according to the first embodiment, immediately after the rectified voltage Vr increases from 0 V in accordance with the increase in the AC voltage, the rectified voltage Vr is less than the determination voltage, and thus the Zener diode ZD1 is not turned on. Accordingly, the NPN transistor Q2 is turned off. On the other hand, since the current flows to the base of the NPN transistor Q1 via the second resistor R2 by the rectified voltage Vr, the NPN transistor Q1 is turned on. As a result, a current flows through the resistance component Rssr of the semiconductor relay SSR in the off state, the rectifying element B1, the first resistor R1, and the NPN transistor Q1. Therefore, the AC voltage from the AC power source E is divided by the resistance component Rssr and the first resistor R1 of the semiconductor relay SSR. The obtained rectified voltage Vr is stepped down below the determination voltage as described above. Therefore, even if the AC voltage is maximized, no current flows through the LED element 11, and thus the LED element 11 is not lit.

比較例のＬＥＤ点灯装置１００でも、以上と同様に、ツェナーダイオードＺＤ１は導通せず、ＬＥＤ素子１１にも電流は流れない。従って、トランジスタＱ１がオンし、トランジスタＱ２がオフする。整流電圧Ｖｒは、抵抗成分Ｒｓｓｒと第１抵抗Ｒ１とによって判定電圧未満に降圧される。これにより、ＬＥＤ素子１１は点灯しない。 In the LED lighting device 100 of the comparative example as well, the zener diode ZD1 is not conducted, and no current flows through the LED element 11 as described above. Therefore, the transistor Q1 is turned on and the transistor Q2 is turned off. The rectified voltage Vr is stepped down below the determination voltage by the resistance component Rssr and the first resistor R1. Thereby, the LED element 11 does not light up.

（２）半導体リレーＳＳＲがオン時
この時、実施例１のＬＥＤ点灯装置１０は、比較例のＬＥＤ点灯装置１００とは異なるタイミングで動作する。このことについて、図３を参照して以下に詳しく説明する。 (2) When the semiconductor relay SSR is ON At this time, the LED lighting device 10 of the first embodiment operates at a timing different from that of the LED lighting device 100 of the comparative example. This will be described in detail below with reference to FIG.

図３は、本発明の実施例１に係るＬＥＤ点灯装置１０と、比較例に係るＬＥＤ点灯装置１００との電流及び電圧を示す波形図である。図３は、半導体リレーＳＳＲがオン時の各波形を、交流電圧の１／２周期に対応する期間だけ示している。図３（ａ）は、整流電圧Ｖｒと、ＬＥＤ素子１１の電流とを示す。図３（ｂ）は、比較例のＬＥＤ点灯装置１００の第１抵抗Ｒ１の電流を示す。図３（ｃ）は、実施例１のＬＥＤ点灯装置１０の第１抵抗Ｒ１の電流を示す。 FIG. 3 is a waveform diagram showing current and voltage of the LED lighting device 10 according to the first embodiment of the present invention and the LED lighting device 100 according to the comparative example. FIG. 3 shows each waveform when the semiconductor relay SSR is on only for a period corresponding to a half cycle of the AC voltage. FIG. 3A shows the rectified voltage Vr and the current of the LED element 11. FIG.3 (b) shows the electric current of 1st resistance R1 of the LED lighting device 100 of a comparative example. FIG.3 (c) shows the electric current of 1st resistance R1 of the LED lighting device 10 of Example 1. FIG.

半導体リレーＳＳＲがオン時、交流電圧は閉状態のスイッチＳＷ１を介して直接的に供給されるため、整流電圧Ｖｒは交流電圧とほぼ等しい電圧となる。実施例１のＬＥＤ点灯装置１０において、時刻ｔ１からｔ２まで、交流電圧の増加に応じて整流電圧Ｖｒが０Ｖから増加していくと、整流電圧Ｖｒは判定電圧未満であるため、ツェナーダイオードＺＤ１は導通しない。一方、整流電圧Ｖｒによって、第２抵抗Ｒ２を介してＮＰＮトランジスタＱ１のベースに電流が流れるので、ＮＰＮトランジスタＱ１がオンして、第１抵抗Ｒ１に電流が流れる。図３（ｃ）に示すように、整流電圧Ｖｒの増加に合わせて第１抵抗Ｒ１の電流は増加する。 When the semiconductor relay SSR is turned on, the AC voltage is directly supplied through the closed switch SW1, so that the rectified voltage Vr is substantially equal to the AC voltage. In the LED lighting device 10 according to the first embodiment, when the rectified voltage Vr increases from 0 V as the AC voltage increases from the time t1 to the time t2, the rectified voltage Vr is less than the determination voltage, so the Zener diode ZD1 Not conducting. On the other hand, the rectified voltage Vr causes a current to flow to the base of the NPN transistor Q1 via the second resistor R2, so that the NPN transistor Q1 is turned on and a current flows to the first resistor R1. As shown in FIG. 3C, the current of the first resistor R1 increases as the rectified voltage Vr increases.

時刻ｔ２において、整流電圧Ｖｒが判定電圧に達すると、ツェナーダイオードＺＤ１は導通する。これにより、ツェナーダイオードＺＤ１及び第５抵抗Ｒ４を介してＮＰＮトランジスタＱ２のベースに電流が流れるので、ＮＰＮトランジスタＱ２がオンして、第２抵抗Ｒ２に流れる電流が増加する。すると、ＮＰＮトランジスタＱ１のベース電圧が低下して、ＮＰＮトランジスタＱ１はオフする。従って、図３（ｃ）に示すように、第１抵抗Ｒ１に電流が流れないようになる。前述のように、第２抵抗Ｒ２は第１抵抗Ｒ１の数十倍の抵抗値を有するので、第２抵抗Ｒ２に流れる電流は、第１抵抗Ｒ１に流れる電流に比して十分に小さい。 When the rectified voltage Vr reaches the determination voltage at time t2, the Zener diode ZD1 becomes conductive. As a result, a current flows to the base of the NPN transistor Q2 via the Zener diode ZD1 and the fifth resistor R4, so that the NPN transistor Q2 is turned on and the current flowing to the second resistor R2 increases. Then, the base voltage of the NPN transistor Q1 is lowered and the NPN transistor Q1 is turned off. Therefore, as shown in FIG. 3C, no current flows through the first resistor R1. As described above, since the second resistor R2 has a resistance value several tens of times that of the first resistor R1, the current flowing through the second resistor R2 is sufficiently smaller than the current flowing through the first resistor R1.

時刻ｔ３において、整流電圧Ｖｒが、ＬＥＤ素子１１が点灯するために必要な電圧以上になると、図３（ａ）に示すように、ＬＥＤ素子１１に電流が流れる。 When the rectified voltage Vr becomes equal to or higher than the voltage necessary for the LED element 11 to light at time t3, a current flows through the LED element 11 as shown in FIG.

時刻ｔ４において、整流電圧Ｖｒが、ＬＥＤ素子１１が点灯するために必要な電圧未満になると、図３（ａ）に示すように、ＬＥＤ素子１１に電流が流れないようになる。 When the rectified voltage Vr becomes less than a voltage necessary for the LED element 11 to light at time t4, no current flows through the LED element 11 as shown in FIG.

時刻ｔ５から時刻ｔ６において、整流電圧Ｖｒが判定電圧未満になると、ツェナーダイオードＺＤ１は導通しないようになる。従って、図３（ｃ）に示すように、時刻ｔ１からｔ２と同様に、第１抵抗Ｒ１に電流が流れる。 From time t5 to time t6, when the rectified voltage Vr becomes less than the determination voltage, the Zener diode ZD1 does not conduct. Accordingly, as shown in FIG. 3C, a current flows through the first resistor R1 in the same manner as from time t1 to time t2.

このように、時刻ｔ１からｔ２及び時刻ｔ５からｔ６の各期間Ｔ２において、第１抵抗Ｒ１に電流が流れ、時刻ｔ２からｔ５において、第１抵抗Ｒ１に電流が流れず、第２抵抗Ｒ２に電流が流れる。 Thus, in each period T2 from time t1 to t2 and from time t5 to t6, current flows through the first resistor R1, and from time t2 to t5, no current flows through the first resistor R1, and current flows through the second resistor R2. Flows.

これに対して、比較例のＬＥＤ点灯装置１００では、時刻ｔ１からｔ３まで、整流電圧Ｖｒが０Ｖから増加していくが、整流電圧ＶｒはＬＥＤ素子１１が点灯するために必要な電圧未満であるため、ＬＥＤ素子１１に電流は流れない。従って、ＮＰＮトランジスタＱ２がオフする。一方、整流電圧Ｖｒによって、第２抵抗Ｒ２を介してＮＰＮトランジスタＱ１のベースに電流が流れるので、ＮＰＮトランジスタＱ１がオンして、第１抵抗Ｒ１に電流が流れる。図３（ｂ）に示すように、整流電圧Ｖｒの増加に合わせて第１抵抗Ｒ１の電流は増加する。 On the other hand, in the LED lighting device 100 of the comparative example, the rectified voltage Vr increases from 0 V from time t1 to t3, but the rectified voltage Vr is less than a voltage necessary for the LED element 11 to light. Therefore, no current flows through the LED element 11. Accordingly, the NPN transistor Q2 is turned off. On the other hand, the rectified voltage Vr causes a current to flow to the base of the NPN transistor Q1 via the second resistor R2, so that the NPN transistor Q1 is turned on and a current flows to the first resistor R1. As shown in FIG. 3B, the current of the first resistor R1 increases as the rectified voltage Vr increases.

時刻ｔ３において、整流電圧Ｖｒが、ＬＥＤ素子１１が点灯するために必要な電圧以上になると、図３（ａ）に示すように、ＬＥＤ素子１１に電流が流れる。これにより、第５抵抗Ｒ４を介してＮＰＮトランジスタＱ２のベースに電流が流れるので、ＮＰＮトランジスタＱ２がオンして、第２抵抗Ｒ２に流れる電流が増加する。すると、ＮＰＮトランジスタＱ１はオフする。従って、図３（ｂ）に示すように、第１抵抗Ｒ１に電流が流れないようになる。 When the rectified voltage Vr becomes equal to or higher than the voltage necessary for the LED element 11 to light at time t3, a current flows through the LED element 11 as shown in FIG. As a result, a current flows to the base of the NPN transistor Q2 via the fifth resistor R4, so the NPN transistor Q2 is turned on and the current flowing to the second resistor R2 increases. Then, the NPN transistor Q1 is turned off. Accordingly, as shown in FIG. 3B, no current flows through the first resistor R1.

時刻ｔ４において、整流電圧Ｖｒが、ＬＥＤ素子１１が点灯するために必要な電圧未満になると、図３（ａ）に示すように、ＬＥＤ素子１１に電流が流れないようになる。従って、時刻ｔ１からｔ３と同様に、第１抵抗Ｒ１に電流が流れる。 When the rectified voltage Vr becomes less than a voltage necessary for the LED element 11 to light at time t4, no current flows through the LED element 11 as shown in FIG. Accordingly, a current flows through the first resistor R1 as from time t1 to time t3.

このように、比較例のＬＥＤ点灯装置１００では、時刻ｔ１からｔ３及び時刻ｔ４からｔ６の各期間Ｔ１に、第１抵抗Ｒ１に電流が流れる。即ち、ＬＥＤ素子１１に電流が流れていない全期間で、第１抵抗Ｒ１に電流が流れる。また、時刻ｔ３からｔ４において、第１抵抗Ｒ１に電流が流れず、第２抵抗Ｒ２に電流が流れる。 Thus, in the LED lighting device 100 of the comparative example, a current flows through the first resistor R1 during each period T1 from time t1 to t3 and from time t4 to t6. That is, the current flows through the first resistor R1 during the entire period when no current flows through the LED element 11. In addition, from time t3 to t4, no current flows through the first resistor R1, and a current flows through the second resistor R2.

一方、本実施例のＬＥＤ点灯装置１０では、前述のように、ＬＥＤ素子１１に電流が流れていない期間の一部、即ち整流電圧Ｖｒが判定電圧より低い期間で、第１抵抗Ｒ１に電流が流れる。従って、比較例のＬＥＤ点灯装置１００よりも、第１抵抗Ｒ１に電流が流れる期間を大幅に短縮できる。これにより、第１抵抗Ｒ１に流れる電流の最大値及び総量、並びに、第１抵抗Ｒ１に印加される電圧の最大値を低減できるので、第１抵抗Ｒ１での電力の損失も大幅に削減できる。 On the other hand, in the LED lighting device 10 according to the present embodiment, as described above, the current is supplied to the first resistor R1 during a part of the period in which the current does not flow through the LED element 11, that is, the rectified voltage Vr is lower than the determination voltage. Flowing. Therefore, the period during which current flows through the first resistor R1 can be significantly shortened compared to the LED lighting device 100 of the comparative example. Thereby, since the maximum value and the total amount of the current flowing through the first resistor R1 and the maximum value of the voltage applied to the first resistor R1 can be reduced, the power loss in the first resistor R1 can also be greatly reduced.

以上で説明したように、本実施例に係るＬＥＤ点灯装置１０によれば、抵抗切り替え部１３が、整流電圧Ｖｒが判定電圧未満の時、第１抵抗Ｒ１を、整流素子Ｂ１を介して半導体リレーＳＳＲに電気的に接続するようにしている。また、抵抗切り替え部１３が、整流電圧Ｖｒが判定電圧以上の時、第１抵抗Ｒ１より高抵抗である第２抵抗Ｒ２を、整流素子Ｂ１を介して半導体リレーＳＳＲに電気的に接続するようにしている。また、上記判定電圧は、ＬＥＤ素子１１が点灯するために必要な電圧未満になるようにしている。これにより、半導体リレーＳＳＲがオフ時には、整流電圧Ｖｒは、半導体リレーＳＳＲの抵抗成分Ｒｓｓｒと第１抵抗Ｒ１とによって降圧されるので、半導体リレーＳＳＲの抵抗成分Ｒｓｓｒが存在しても、ＬＥＤ素子１１を点灯しないようにできる。 As described above, according to the LED lighting device 10 according to the present embodiment, when the resistance switching unit 13 has the rectified voltage Vr less than the determination voltage, the first resistor R1 is connected to the semiconductor relay via the rectifying element B1. Electrical connection is made to the SSR. Further, when the rectified voltage Vr is equal to or higher than the determination voltage, the resistance switching unit 13 electrically connects the second resistor R2 having a higher resistance than the first resistor R1 to the semiconductor relay SSR through the rectifier element B1. ing. The determination voltage is set to be less than a voltage necessary for the LED element 11 to light up. As a result, when the semiconductor relay SSR is off, the rectified voltage Vr is stepped down by the resistance component Rssr and the first resistance R1 of the semiconductor relay SSR, so that even if the resistance component Rssr of the semiconductor relay SSR exists, the LED element 11 Can be turned off.

また、半導体リレーＳＳＲがオン時には、整流電圧Ｖｒが判定電圧以上になると、電流は第１抵抗Ｒ１に流れず高抵抗な第２抵抗Ｒ２に流れる。従って、ＬＥＤ素子１１の点灯に寄与しない電流が低抵抗な第１抵抗Ｒ１に流れる期間を、比較例のＬＥＤ点灯装置１００より短縮して、電力損失及び発熱量を低減できる。発熱量を低減できることで、歩行者用信号機の低い放熱性にも拘らず、ＬＥＤ点灯装置１０の耐久性及び信頼性を向上できる。 Further, when the semiconductor relay SSR is turned on, if the rectified voltage Vr becomes equal to or higher than the determination voltage, the current does not flow through the first resistor R1 but flows through the high resistance second resistor R2. Therefore, the period during which the current that does not contribute to the lighting of the LED element 11 flows through the first resistor R1 having a low resistance can be shortened compared to the LED lighting device 100 of the comparative example, thereby reducing power loss and heat generation. Since the amount of generated heat can be reduced, the durability and reliability of the LED lighting device 10 can be improved despite the low heat dissipation of the pedestrian traffic light.

このように、本実施例に係るＬＥＤ点灯装置１０では、第１抵抗Ｒ１の電力損失及び発熱量を低減できるので、第１抵抗Ｒ１として、比較例のものより小型、低耐圧且つ小電力な抵抗器を用いることもできる。従って、低コスト化できる。 As described above, in the LED lighting device 10 according to the present embodiment, the power loss and the heat generation amount of the first resistor R1 can be reduced. Therefore, the first resistor R1 has a smaller, lower withstand voltage and lower power resistor than that of the comparative example. A vessel can also be used. Therefore, the cost can be reduced.

さらに、第１抵抗Ｒ１に電流が流れる期間を短縮できることで、第１抵抗Ｒ１を比較例のものより低抵抗にしても、電力損失及び発熱量を比較例より低減できる。これにより、比較例より抵抗成分Ｒｓｓｒが低い半導体リレーＳＳＲを用いても、半導体リレーＳＳＲがオフ時に、整流電圧Ｖｒを十分に降圧させて、ＬＥＤ素子１１を点灯しないようにできる。従って、様々な形式（メーカー）の半導体リレーＳＳＲを用いることができる。 Furthermore, since the period during which a current flows through the first resistor R1 can be shortened, even if the first resistor R1 has a lower resistance than that of the comparative example, power loss and heat generation can be reduced as compared with the comparative example. Thus, even when the semiconductor relay SSR having the resistance component Rssr lower than that of the comparative example is used, the rectified voltage Vr can be sufficiently lowered when the semiconductor relay SSR is turned off so that the LED element 11 is not lit. Therefore, various types (manufacturers) of semiconductor relays SSR can be used.

また、第１抵抗Ｒ１に電流が流れる期間は、整流電圧Ｖｒによって決定される。従って、その期間は、直列接続されたＬＥＤの数、ＬＥＤ素子１１の通電幅、及び、ＬＥＤ素子１１の電流値等には影響されない。これに対して、比較例では、直列接続されたＬＥＤの数を増加させた場合や、ＬＥＤ素子１１の通電幅を減少させた場合には、ＬＥＤ素子１１に電流が流れる期間が短くなるので、その分、第１抵抗Ｒ１に電流が流れる期間が増加し、その結果、電力の損失が増加する。 The period during which current flows through the first resistor R1 is determined by the rectified voltage Vr. Therefore, the period is not affected by the number of LEDs connected in series, the energization width of the LED element 11, the current value of the LED element 11, and the like. On the other hand, in the comparative example, when the number of LEDs connected in series is increased or when the energization width of the LED element 11 is decreased, the period in which the current flows through the LED element 11 is shortened. Accordingly, the period during which current flows through the first resistor R1 increases, and as a result, power loss increases.

実施例２は、電流制御部の構成が実施例１と異なる。 The second embodiment is different from the first embodiment in the configuration of the current control unit.

図４は、本発明の実施例２に係るＬＥＤ点灯装置１０ａを備える表示装置の回路図である。電流制御部１２ａは、ＬＥＤ素子１１と整流素子Ｂ１の第２端子Ｔ２との間に接続された電流制御抵抗Ｒ５ａを有する。抵抗切り替え部１３において、ツェナーダイオードＺＤ１のアノードは第５抵抗Ｒ４のみに接続されている。その他の構成は、図１の実施例１の構成と同一であるため、同一の構成要素に同一の符号を付し、説明を省略する。 FIG. 4 is a circuit diagram of a display device including the LED lighting device 10a according to the second embodiment of the present invention. The current control unit 12a includes a current control resistor R5a connected between the LED element 11 and the second terminal T2 of the rectifying element B1. In the resistance switching unit 13, the anode of the Zener diode ZD1 is connected only to the fifth resistor R4. Since other configurations are the same as those of the first embodiment shown in FIG. 1, the same components are denoted by the same reference numerals and description thereof is omitted.

上記構成により、整流電圧Ｖｒが、ＬＥＤ素子１１が点灯するために必要な電圧以上に増加した時に、ＬＥＤ素子１１と電流制御抵抗Ｒ５ａに電流が流れて、ＬＥＤ素子１１が点灯する。また、抵抗切り替え部１３は、実施例１と同様に動作する。従って、本実施例のＬＥＤ点灯装置１０ａによっても、実施例１と同様の効果が得られる。 With the above configuration, when the rectified voltage Vr increases to a voltage higher than that necessary for the LED element 11 to light, current flows through the LED element 11 and the current control resistor R5a, and the LED element 11 lights. The resistance switching unit 13 operates in the same manner as in the first embodiment. Therefore, the effect similar to Example 1 is acquired also by the LED lighting device 10a of a present Example.

以上、本発明の実施例を詳述してきたが、具体的な構成は上記実施例に限定されるものではなく、本発明の要旨を逸脱しない範囲で種々に変形して実施することができる。 As mentioned above, although the Example of this invention was explained in full detail, a concrete structure is not limited to the said Example, A various deformation | transformation can be implemented in the range which does not deviate from the summary of this invention.

例えば、上記各実施例では、スイッチ部は半導体リレーＳＳＲである一例について説明したが、これに限られない。つまり、スイッチ部は、オフ時に交流電圧を遮断できない特性を有する素子であれば良い。例えば、スイッチ部は、交流電源Ｅからの交流電圧が供給され、オン又はオフに切り替えられ且つオフ時に抵抗成分を有する調光器（ディマー）でも良い。例えば、調光器は、オン時にはＬＥＤ素子１１の明るさを調光できる。また、調光器は、オフ時には抵抗成分を有するが、上記各実施例のＬＥＤ点灯装置１０，１０ａによれば、ＬＥＤ素子１１を消灯できる。 For example, in each of the above embodiments, an example in which the switch unit is the semiconductor relay SSR has been described, but the present invention is not limited to this. That is, the switch unit may be an element having a characteristic that cannot interrupt the AC voltage when it is off. For example, the switch unit may be a dimmer that is supplied with an AC voltage from the AC power supply E, switched on or off, and has a resistance component when turned off. For example, the dimmer can dimm the brightness of the LED element 11 when turned on. Further, the dimmer has a resistance component when turned off, but the LED element 11 can be turned off according to the LED lighting devices 10 and 10a of the respective embodiments.

また、表示装置が歩行者用信号機を構成している一例を説明したが、これに限られない。表示装置は、自動車用信号機を構成しても良く、また、ＬＥＤ素子１１の点灯及び消灯によって何らかの情報を表示するような装置でも良い。
さらに、ＬＥＤ素子１１は、１つ又は複数のＬＥＤで構成されていても良い。 Moreover, although the example which the display apparatus comprises the pedestrian traffic light was demonstrated, it is not restricted to this. The display device may constitute an automobile traffic light or may be a device that displays some information by turning on and off the LED element 11.
Further, the LED element 11 may be composed of one or a plurality of LEDs.

１０ＬＥＤ点灯装置
Ｂ１整流素子
１１ＬＥＤ素子
１２電流制御部
１３抵抗切り替え部
ＬＥＤ１〜ＬＥＤ３４ＬＥＤ
ＺＤ１ツェナーダイオード（電圧検出素子）
Ｑ１ＮＰＮトランジスタ（第２のスイッチング素子）
Ｑ２ＮＰＮトランジスタ（第１のスイッチング素子）
Ｑ３Ｎ型ＭＯＳトランジスタ（電流制御素子）
Ｒ１第１抵抗
Ｒ２第２抵抗
Ｒ３第４抵抗
Ｒ４第５抵抗
Ｒ５第３抵抗
Ｒ５ａ電流制御抵抗
ＩＣ１シャントレギュレータ（基準電圧生成素子）
２０信号機制御盤（制御部）
ＳＳＲ半導体リレー（スイッチ部）
Ｒｓｓｒ抵抗成分
ＳＷ１スイッチ DESCRIPTION OF SYMBOLS 10 LED lighting apparatus B1 Rectifier element 11 LED element 12 Current control part 13 Resistance switching part LED1-LED34 LED
ZD1 Zener diode (voltage detection element)
Q1 NPN transistor (second switching element)
Q2 NPN transistor (first switching element)
Q3 N-type MOS transistor (current control element)
R1 1st resistance R2 2nd resistance R3 4th resistance R4 5th resistance R5 3rd resistance R5a Current control resistance IC1 Shunt regulator (reference voltage generation element)
20 Traffic light control panel (control unit)
SSR semiconductor relay (switch part)
Rssr resistance component SW1 switch

Claims

An LED lighting device in which an AC voltage from an AC power source is switched on or off and supplied via a switch unit having a resistance component when off,
A rectifying element that rectifies the supplied AC voltage and outputs a rectified voltage between the first terminal and the second terminal;
An LED element to which the rectified voltage is supplied;
A resistance switching unit that includes a first resistor and a second resistor, and switches a resistance between the first terminal and the second terminal based on the supplied rectified voltage;
The resistance switching unit is configured to connect the first resistor between the first terminal and the second terminal when the rectified voltage is lower than a determination voltage, and thereby connect the first resistor to the switch unit via the rectifying element. When the rectified voltage is equal to or higher than the determination voltage, the second resistor having a higher resistance than the first resistor is provided between the first terminal and the second terminal instead of the first resistor. And thereby electrically connecting the second resistor to the switch part via the rectifying element,
The determination voltage is less than a voltage necessary for the LED element to light up,
The LED lighting device, wherein when the switch unit is off, the rectified voltage is stepped down below the determination voltage by the resistance component of the switch unit and the first resistor.

The LED lighting device according to claim 1, wherein the first resistor has a lower resistance than the resistance component of the switch unit.

The resistance switching unit
A voltage detection element having one end connected to the first terminal and conducting when the rectified voltage is equal to or higher than the determination voltage;
A control terminal is connected to the other end of the voltage detection element, one end and the other end are connected between the second resistor and the second terminal, and the first switching element is turned on when the voltage detection element is turned on When,
A control terminal is connected to the one end of the first switching element, one end and the other end are connected between the first resistor and the second terminal, and the first switching element is turned off when the first switching element is turned on. The LED lighting device according to claim 1, wherein the LED lighting device includes two switching elements.

The LED lighting device according to claim 3, further comprising a current control unit that is connected between the LED element and the second terminal of the rectifying element and controls a current flowing through the LED element.

The current controller is
A current control element having one end connected to the LED element;
A third resistor connected between the other end of the current control element and the second terminal;
A fourth resistor having one end connected to the first terminal;
One end connected to the other end of the fourth resistor, the other end connected to the second terminal, and a reference voltage generating element that supplies the generated reference voltage to the control terminal of the current control element from the one end. The LED lighting device according to claim 4.

The LED lighting device according to claim 5, wherein one end of the fourth resistor is connected to the first terminal via the voltage detection element.

The LED lighting device according to claim 4, wherein the current control unit includes a current control resistor connected between the LED element and the second terminal of the rectifying element.

The LED lighting device according to any one of claims 1 to 7, wherein the LED element includes a plurality of LEDs connected in series.

The LED lighting device according to claim 3, wherein the voltage detection element is a Zener diode.

The LED lighting device according to claim 5, wherein the reference voltage generation element is a shunt regulator that generates the reference voltage so that a voltage at the other end of the current control element is constant.

The LED lighting device according to any one of claims 1 to 10, wherein a resistance value of the second resistor is ten times or more of a resistance value of the first resistor.

The resistance switching unit
The LED lighting according to any one of claims 3 to 7, further comprising a fifth resistor connected between the other end of the voltage detection element and a control terminal of the first switching element. apparatus.

The LED lighting device according to any one of claims 3 to 7, wherein the first switching element and the second switching element are NPN transistors.

It said current control element, LED lighting device according to claim 5 or claim 6, characterized in that an N-type MOS transistor.

An alternating voltage from an alternating current power source is supplied, switched on or off, and having a resistance component when turned off;
A rectifying element that rectifies an alternating voltage supplied via the switch unit and outputs a rectified voltage between the first terminal and the second terminal;
An LED element to which the rectified voltage is supplied;
A resistance switching unit that includes a first resistor and a second resistor, and switches a resistance between the first terminal and the second terminal based on the supplied rectified voltage;
The resistance switching unit is configured to connect the first resistor between the first terminal and the second terminal when the rectified voltage is lower than a determination voltage, and thereby connect the first resistor to the switch unit via the rectifying element. When the rectified voltage is equal to or higher than the determination voltage, the second resistor having a higher resistance than the first resistor is provided between the first terminal and the second terminal instead of the first resistor. And thereby electrically connecting the second resistor to the switch part via the rectifying element,
The determination voltage is less than a voltage necessary for the LED element to light up,
When the switch unit is off, the rectified voltage is stepped down to less than the determination voltage by the resistance component of the switch unit and the first resistor.