JP2010114224A - Light-emitting diode (led) lighting device - Google Patents

Light-emitting diode (led) lighting device Download PDF

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JP2010114224A
JP2010114224A JP2008284856A JP2008284856A JP2010114224A JP 2010114224 A JP2010114224 A JP 2010114224A JP 2008284856 A JP2008284856 A JP 2008284856A JP 2008284856 A JP2008284856 A JP 2008284856A JP 2010114224 A JP2010114224 A JP 2010114224A
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JP5153578B2 (en
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Matsuo Uno
松夫 宇野
Kazuyoshi Kiyono
一喜 清野
Yukiya Takahashi
幸也 高橋
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AW JAPAN KK
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Abstract

<P>PROBLEM TO BE SOLVED: To provide an LED lighting device for actualizing constant current drive even if the number of LEDs is varied without causing a problem of heat generation and for providing a switch for turning the LED ON and OFF in series to a serial LED circuit. <P>SOLUTION: The LED lighting device includes a constant current circuit 20 connected in series to the LED serial circuit 2 for controlling a current i<SB>c</SB>flowing through the LED serial circuit to the predetermined constant current, a stabilizing power supply circuit 10 for controlling a feedback voltage not to exceed the predetermined voltage by feeding back an output voltage +V for the LED serial circuit, and an output voltage control circuit 30 for supplying a feedback signal FB to the stabilizing power supply circuit 10 to control the voltage of constant current circuit 20 to the predetermined constant voltage. The stabilizing power supply circuit 10 variably controls the output voltage +V in accordance with addition of the feedback signal by adding the feedback signal FB from the output voltage control circuit 30 to the feedback route of the output voltage +V. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

本発明は、例えば照明器具や液晶のバックライト等に使用されるＬＥＤ（発光ダイオード）を点灯するためのＬＥＤ点灯装置に関する。   The present invention relates to an LED lighting device for lighting an LED (light emitting diode) used in, for example, a lighting fixture or a liquid crystal backlight.

ＬＥＤを照明器具や大型のフラットディスプレイ等に使用する場合は、複数個のＬＥＤを直列接続して駆動するのが一般的である。下記特許文献１には、直流電源とＬＥＤ直列回路との間に定電流素子を直列に接続し、１乃至複数のＬＥＤを定電流駆動する構成が示されている。しかし、そのような構成では、その点灯回路で許容する最大個数のＬＥＤを接続した場合と、それよりも少数のＬＥＤを接続した場合とで、ＬＥＤ直列回路及び定電流素子における全体の消費電力が同じであるため、ＬＥＤ直列回路におけるＬＥＤの数が少ないほど定電流素子が分担する消費電力が増大し、発熱の問題が生じる。   When LEDs are used in lighting equipment, large flat displays, etc., it is common to drive a plurality of LEDs connected in series. Patent Document 1 below shows a configuration in which a constant current element is connected in series between a DC power supply and an LED series circuit to drive one or more LEDs at a constant current. However, in such a configuration, the total power consumption of the LED series circuit and the constant current element is reduced when the maximum number of LEDs allowed in the lighting circuit is connected and when a smaller number of LEDs are connected. Since the same is true, the smaller the number of LEDs in the LED series circuit, the more the power consumed by the constant current element increases, causing the problem of heat generation.

そのような発熱の問題を解決するために、下記特許文献２においては、ＬＥＤ定電流点灯ユニットにおいて定電流制御回路と定電圧制御回路と組み合わせて具備し、該ＬＥＤ定電流点灯ユニットの出力側に負荷としてＬＥＤ直列回路を接続し、該ＬＥＤ直列回路を流れる電流を検出・フィードバックしてこの電流が所定の定電流となるように定電流制御回路によりＬＥＤ定電流点灯ユニットの出力電圧を制御し、かつ、該ＬＥＤ定電流点灯ユニットの出力電圧が所定電圧以上にならないように定電圧制御回路により制御している。   In order to solve such a problem of heat generation, in Patent Document 2 below, an LED constant current lighting unit is provided in combination with a constant current control circuit and a constant voltage control circuit, and on the output side of the LED constant current lighting unit. Connect the LED series circuit as a load, detect and feed back the current flowing through the LED series circuit, and control the output voltage of the LED constant current lighting unit by the constant current control circuit so that this current becomes a predetermined constant current, In addition, the constant voltage control circuit controls so that the output voltage of the LED constant current lighting unit does not exceed a predetermined voltage.

一方、下記特許文献３においては、直流電源とＬＥＤ直列回路との間に定電流制御用トランジスタのコレクタ−エミッタを直列に接続し、複数のＬＥＤを定電流駆動する構成において、該トランジスタのコレクタ電圧が所定電圧以上のときに導通するツェナーダイオードを設け、該ツェナーダイオードが導通したとき定電流動作を解除してＬＥＤ駆動電流を下げることにより、定電流制御用トランジスタの発熱を回避するようにしたことが示されている。しかし、このような構成では、ＬＥＤ直列回路におけるＬＥＤの数が変動したとき、ＬＥＤの定電流駆動が行えない、という不都合がある。
特開２００５−１０９０２５号公報 特開２００７−４９９５号公報 特開２００７−１４２１３９号公報 On the other hand, in the following Patent Document 3, a collector-emitter of a constant current control transistor is connected in series between a DC power supply and an LED series circuit, and a plurality of LEDs are driven at a constant current. A Zener diode that conducts when the voltage is higher than a predetermined voltage is provided, and when the Zener diode conducts, the constant current operation is canceled and the LED drive current is lowered to avoid the heat generation of the constant current control transistor. It is shown. However, such a configuration has a disadvantage that constant current driving of the LEDs cannot be performed when the number of LEDs in the LED series circuit varies.
JP 2005-109025 A Japanese Patent Laid-Open No. 2007-4995 JP 2007-142139 A

ところで、上記特許文献２のようなタイプのＬＥＤ定電流点灯ユニットにおいては、ＬＥＤの点灯／消灯を制御するスイッチは、ＬＥＤ定電流点灯ユニットの出力側にＬＥＤ直列回路に直列に設けることはできなかった。その理由は、そのようにスイッチを設けたとすると、スイッチがＯＦＦのときはユニット内の定電流制御回路を構成する半導体素子は動作状態となっておらず、スイッチＯＮに応じてＬＥＤ直列回路に駆動電流が流れた後に該駆動電流の検出・フィードバック信号に基づき該半導体素子の動作が開始するため、該半導体素子の動作遅れにより、スイッチＯＦＦからＯＮに切り替わった直後の短時間の間、定電流動作が正常に行われないからである。その場合、その間は、ユニット開放電圧がＬＥＤ直列回路に印加され、過大な電流がＬＥＤに流れ、ＬＥＤへのストレスあるいは損傷といった問題が生じる。   By the way, in the LED constant current lighting unit of the type as described in Patent Document 2, a switch for controlling the turning on / off of the LED cannot be provided in series with the LED series circuit on the output side of the LED constant current lighting unit. It was. The reason is that if a switch is provided in such a manner, when the switch is OFF, the semiconductor elements constituting the constant current control circuit in the unit are not in the operating state, and are driven to the LED series circuit according to the switch ON. Since the operation of the semiconductor element starts based on the detection / feedback signal of the drive current after the current flows, the constant current operation is performed for a short time immediately after the switch is switched from OFF to ON due to the operation delay of the semiconductor element. This is because is not performed normally. In that case, a unit open voltage is applied to the LED series circuit during that period, and an excessive current flows through the LED, causing problems such as stress or damage to the LED.

しかし、照明器具にＬＥＤを多用する傾向になると、ＬＥＤ定電流点灯ユニットとＬＥＤ直列回路との距離が離れ、その間にスイッチを設ける、といった使い方が要求されることになる。そのような要求に応えることができるようにするには、ＬＥＤ点灯／消灯制御用のスイッチを、ＬＥＤ定電流点灯ユニットの出力側にＬＥＤ直列回路と直列に設けることができるようにする必要がある。   However, if the LED tends to be used frequently in the lighting fixture, the usage of providing a switch between the LED constant current lighting unit and the LED series circuit is required. In order to be able to meet such demands, it is necessary to provide a switch for LED lighting / extinguishing control in series with the LED series circuit on the output side of the LED constant current lighting unit. .

本発明は、上述の点に鑑みてなされたもので、ＬＥＤ直列回路におけるＬＥＤの数が変動した場合でも定電流駆動を行うことができると共に発熱の問題が生じないＬＥＤ点灯装置を提供しようとするものである。更には、ＬＥＤ点灯／消灯制御用のスイッチをＬＥＤ直列回路と直列に設けることを可能にする構成からなるＬＥＤ点灯装置を提供しようとするものである。   The present invention has been made in view of the above points, and intends to provide an LED lighting device that can be driven at a constant current even when the number of LEDs in the LED series circuit fluctuates and does not cause a problem of heat generation. Is. Furthermore, the present invention intends to provide an LED lighting device having a configuration that enables a switch for LED lighting / extinguishing control to be provided in series with an LED series circuit.

本発明は、１乃至複数のＬＥＤを直列接続したＬＥＤ直列回路に対して電力を供給するＬＥＤ点灯装置であって、前記ＬＥＤ直列回路に直列接続され、該ＬＥＤ直列回路を流れる電流を所定の定電流に制御する定電流回路と、前記ＬＥＤ直列回路に電力を供給する安定化電源回路であって、該ＬＥＤ直列回路に対する出力電圧をフィードバックして該フィードバックされた電圧が所定電圧を超えないように制御するものと、前記定電流回路の電圧を所定の定電圧に制御するよう前記安定化電源回路にフィードバック信号を供給する出力電圧制御回路とを備え、前記安定化電源回路では、前記出力電圧のフィードバック経路に前記出力電圧制御回路から供給される前記フィードバック信号を追加することで、該フィードバック信号の追加に応じて前記出力電圧を可変制御するようにしたことを特徴とする。   The present invention is an LED lighting device that supplies electric power to an LED series circuit in which one or more LEDs are connected in series. The LED lighting device is connected in series to the LED series circuit, and a current flowing through the LED series circuit is determined in a predetermined manner. A constant current circuit for controlling the current, and a stabilized power supply circuit for supplying power to the LED series circuit, wherein the output voltage to the LED series circuit is fed back so that the fed back voltage does not exceed a predetermined voltage. And an output voltage control circuit for supplying a feedback signal to the stabilized power supply circuit so as to control the voltage of the constant current circuit to a predetermined constant voltage. In the stabilized power supply circuit, By adding the feedback signal supplied from the output voltage control circuit to the feedback path, according to the addition of the feedback signal And characterized in that said output voltage is variably controlled.

本発明によれば、定電流回路は、ＬＥＤ直列回路に直列接続され、該ＬＥＤ直列回路を流れる電流を所定の定電流に制御し、安定化電源回路は、ＬＥＤ直列回路に対する出力電圧が所定電圧を超えないように制御して該ＬＥＤ直列回路に電力を供給する。これにより、安定化電源回路の出力電圧の前記所定電圧の範囲内で任意の複数のＬＥＤをＬＥＤ直列回路に接続して、これらのＬＥＤを定電流駆動できる。更に、出力電圧制御回路により、前記定電流回路の電圧を所定の定電圧に制御するよう前記安定化電源回路にフィードバック信号を供給し、安定化電源回路では、出力電圧のフィードバック経路に該フィードバック信号を追加することで該フィードバック信号の追加に応じて前記出力電圧を可変制御することにより、定電流回路の電圧を所定の定電圧に制御することが実現される。従って、定電流回路の電圧が上昇しようとするときに安定化電源回路の出力電圧を低下させることでその上昇を防ぎ、該定電流回路の消費電力を一定に保つことができ、これにより、ＬＥＤ直列回路に接続するＬＥＤの数が減少したときに発熱の問題が生じないようになる。また、定電流回路は、ＬＥＤ直列回路に直列接続されて、該ＬＥＤ直列回路を流れる電流を所定の定電流に制御することを直接行うので、動作時間遅れがない。従って、ＬＥＤ点灯／消灯制御用のスイッチをＬＥＤ直列回路に直列に設けたときに、動作時間遅れなしに定電流制御を行うことができ、ＬＥＤの劣化や損傷を防ぐことができる。   According to the present invention, the constant current circuit is connected in series to the LED series circuit, the current flowing through the LED series circuit is controlled to a predetermined constant current, and the stabilized power supply circuit has an output voltage for the LED series circuit of a predetermined voltage. The power is supplied to the LED series circuit by controlling so as not to exceed. Thereby, arbitrary LED can be connected to LED series circuit within the range of the said predetermined voltage of the output voltage of a stabilized power supply circuit, and these LEDs can be driven by constant current. Further, the output voltage control circuit supplies a feedback signal to the stabilized power supply circuit so as to control the voltage of the constant current circuit to a predetermined constant voltage, and the stabilized power supply circuit supplies the feedback signal to the feedback path of the output voltage. By controlling the output voltage in response to the addition of the feedback signal, the voltage of the constant current circuit can be controlled to a predetermined constant voltage. Therefore, when the voltage of the constant current circuit is about to rise, the output voltage of the stabilized power supply circuit is lowered to prevent the rise, and the power consumption of the constant current circuit can be kept constant. The problem of heat generation does not occur when the number of LEDs connected to the series circuit decreases. Further, the constant current circuit is connected in series to the LED series circuit and directly controls the current flowing through the LED series circuit to a predetermined constant current, so there is no operation time delay. Therefore, when the LED on / off control switch is provided in series with the LED series circuit, constant current control can be performed without delay in operation time, and deterioration or damage of the LED can be prevented.

以下、添付図面を参照して本発明の実施例を詳細に説明しよう。
図１は本発明の一実施例に係るＬＥＤ点灯装置１の回路図である。ＬＥＤ点灯装置１は、大別して、安定化電源回路１０と、定電流回路２０と、出力電圧制御回路３０とで構成され、商用交流電源ＡＣを入力して交直変換を行い、直流の出力電圧＋Ｖを出力端子Ｔ１から出力する。ＬＥＤ点灯装置１の２つの出力端子Ｔ１，Ｔ２の間に、１乃至複数個のＬＥＤを直列接続したＬＥＤ直列回路２が接続される。また、出力端子Ｔ１の側においてＬＥＤ直列回路２に直列にスイッチ３が設けられる。更に、スイッチ３に対して直列にかつＬＥＤ直列回路２に対して並列にサージ吸収用のコンデンサ４を設けるとよい。図２は、定電流回路２０及び出力電圧制御回路３０、並びに安定化電源回路１０の一部、を拡大して示す回路図である。 Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a circuit diagram of an LED lighting device 1 according to an embodiment of the present invention. The LED lighting device 1 is roughly composed of a stabilized power supply circuit 10, a constant current circuit 20, and an output voltage control circuit 30. The commercial AC power supply AC is input to perform AC / DC conversion, and a DC output voltage + V Is output from the output terminal T1. An LED series circuit 2 in which one or a plurality of LEDs are connected in series is connected between two output terminals T1 and T2 of the LED lighting device 1. A switch 3 is provided in series with the LED series circuit 2 on the output terminal T1 side. Further, a surge absorbing capacitor 4 may be provided in series with the switch 3 and in parallel with the LED series circuit 2. FIG. 2 is an enlarged circuit diagram showing the constant current circuit 20, the output voltage control circuit 30, and a part of the stabilized power supply circuit 10. As shown in FIG.

定電流回路２０は、出力端子Ｔ２を介してＬＥＤ直列回路２に直列接続され、該ＬＥＤ直列回路２を流れる電流を所定の定電流に制御するものである。詳しくは、図２に示すように、トランジスタＱ１のコレクタ−エミッタ接合と抵抗Ｒ１，Ｒ２とによって直列回路が構成され、トランジスタＱ１のコレクタ側が出力端子Ｔ２に接続されることで、Ｑ１，Ｒ１，Ｒ２の直列回路がＬＥＤ直列回路２に直列接続される。トランジスタＱ１のベースには抵抗Ｒ３を介して安定化電源回路１０の主電源出力ライン１１からの直流電圧（出力電圧＋Ｖ）が電源電圧として印加され、かつ、トランジスタＱ１のベースにはシャントレギュレータＩＣ１のカソードが接続される。シャントレギュレータＩＣ１のリファレンスには、Ｑ１，Ｒ１，Ｒ２直列回路における抵抗Ｒ１，Ｒ２の電圧降下Ｖｒが印加される。シャントレギュレータＩＣ１のアノードは、０ボルト（０ｖ）に接地される。   The constant current circuit 20 is connected in series to the LED series circuit 2 via the output terminal T2, and controls the current flowing through the LED series circuit 2 to a predetermined constant current. Specifically, as shown in FIG. 2, a series circuit is formed by the collector-emitter junction of the transistor Q1 and the resistors R1 and R2, and the collector side of the transistor Q1 is connected to the output terminal T2, whereby Q1, R1, and R2 Are connected in series to the LED series circuit 2. A DC voltage (output voltage + V) from the main power supply output line 11 of the stabilized power supply circuit 10 is applied as a power supply voltage to the base of the transistor Q1 via the resistor R3, and the shunt regulator IC1 of the shunt regulator IC1 is applied to the base of the transistor Q1. The cathode is connected. The voltage drop Vr of the resistors R1 and R2 in the Q1, R1, R2 series circuit is applied to the reference of the shunt regulator IC1. The anode of the shunt regulator IC1 is grounded to 0 volts (0v).

スイッチ３がオンされているとして、定電流回路２０の定電流制御動作について説明する。シャントレギュレータＩＣ１のリファレンスに加わる抵抗Ｒ１，Ｒ２の電圧降下ＶｒがシャントレギュレータＩＣ１の基準電圧以下のときは、シャントレギュレータＩＣ１のカソード−アノード間は不導通（オフ）である。このとき、トランジスタＱ１のコレクタに流せる最大電流は、「抵抗Ｒ３を流れる電流」×「Ｑ１のＨｆｅ（エミッタ接地電流増幅率）」である。抵抗Ｒ１，Ｒ２の電圧降下ＶｒがシャントレギュレータＩＣ１の基準電圧よりも大きくなると、シャントレギュレータＩＣ１のカソード−アノード間が導通（オン）し、抵抗Ｒ３からトランジスタＱ１のベースに流れる電流を抑制してＱ１のコレクタ電流ｉcを抑制し、これに伴い抵抗Ｒ１，Ｒ２の電圧降下Ｖｒが低くなるようにする。電圧降下Ｖｒが基準電圧まで低下すると、シャントレギュレータＩＣ１がオフする。こうして、抵抗Ｒ１，Ｒ２の電圧降下ＶｒがシャントレギュレータＩＣ１の基準電圧に等しくなるように制御され、コレクタ電流ｉcつまりＬＥＤ直列回路２を流れるＬＥＤ駆動電流は、「シャントレギュレータＩＣ１の基準電圧」÷「Ｒ１＋Ｒ２」に相当する値に定電流制御される。 The constant current control operation of the constant current circuit 20 will be described assuming that the switch 3 is turned on. When the voltage drop Vr of the resistors R1 and R2 applied to the reference of the shunt regulator IC1 is equal to or lower than the reference voltage of the shunt regulator IC1, the cathode and anode of the shunt regulator IC1 are not conductive (off). At this time, the maximum current that can flow through the collector of the transistor Q1 is “current flowing through the resistor R3” × “Hfe of Q1 (grounded emitter current amplification factor)”. When the voltage drop Vr of the resistors R1 and R2 becomes larger than the reference voltage of the shunt regulator IC1, the cathode-anode of the shunt regulator IC1 becomes conductive (turns on), and the current flowing from the resistor R3 to the base of the transistor Q1 is suppressed, so that Q1 The collector current ic is suppressed, and the voltage drop Vr of the resistors R1 and R2 is lowered accordingly. When the voltage drop Vr decreases to the reference voltage, the shunt regulator IC1 is turned off. Thus, the voltage drop Vr of the resistors R1 and R2 is controlled to be equal to the reference voltage of the shunt regulator IC1, and the collector current i c, that is, the LED driving current flowing through the LED series circuit 2, is “reference voltage of the shunt regulator IC1” ÷. Constant current control is performed to a value corresponding to “R1 + R2”.

ところで、従来のように、出力電圧制御回路３０を設けずに、安定化電源回路１０により出力電圧＋Ｖを定電圧制御したとすると、ＬＥＤ直列回路２に設けられるＬＥＤの数の違いによって、ＬＥＤ直列回路２が分担する電圧が変動するので、定電流回路２０が分担する電圧が変化する。特に、ＬＥＤの数が少なくなると、ＬＥＤ直列回路２が分担する電圧が小さくなり、その分だけ定電流回路２０が分担する電圧が増大し、定電流回路２０での電力消費が無駄に増加し、発熱の問題が生じる。例えば、出力電圧＋Ｖ＝２０（Ｖ：ボルト）、定電流値＝１（Ａ：アンペア）で、ＬＥＤ１個当りの電圧降下Ｖｆ＝３（Ｖ）、とするとき、ＬＥＤ直列回路２のＬＥＤが５個の場合の定電流回路２の消費電力は（２０−１５）×１＝５（Ｗ：ワット）であるのに対して、ＬＥＤ直列回路２のＬＥＤが１個の場合の定電流回路２の消費電力は（２０−３）×１＝１７（Ｗ）となる。このように、ＬＥＤ直列回路２に直列に定電流回路２０を設けるだけでは、ＬＥＤ直列回路２に接続するＬＥＤの数が少なくなるほど、電力損失が多くなり、発熱も大となる。このような問題を解決するために、本発明では、出力電圧制御回路３０を設けている。   By the way, when the output voltage + V is controlled at a constant voltage by the stabilized power supply circuit 10 without providing the output voltage control circuit 30 as in the prior art, the LED series is different depending on the number of LEDs provided in the LED series circuit 2. Since the voltage shared by the circuit 2 varies, the voltage shared by the constant current circuit 20 changes. In particular, when the number of LEDs decreases, the voltage shared by the LED series circuit 2 decreases, the voltage shared by the constant current circuit 20 increases accordingly, and power consumption in the constant current circuit 20 increases unnecessarily. The problem of heat generation occurs. For example, when the output voltage + V = 20 (V: volt), the constant current value = 1 (A: ampere), and the voltage drop per LED Vf = 3 (V), the number of LEDs in the LED series circuit 2 is 5 The power consumption of the constant current circuit 2 in the case of a single unit is (20−15) × 1 = 5 (W: Watt), whereas the constant current circuit 2 in the case of a single LED series circuit 2 has one LED. The power consumption is (20−3) × 1 = 17 (W). In this way, simply by providing the constant current circuit 20 in series with the LED series circuit 2, the smaller the number of LEDs connected to the LED series circuit 2, the greater the power loss and the greater the heat generation. In order to solve such a problem, an output voltage control circuit 30 is provided in the present invention.

出力電圧制御回路３０は、定電流回路２０の電圧Ｖｃを所定の定電圧に制御するよう安定化電源回路１０にフィードバック信号を供給する。詳しくは、図２に示すように、定電流回路２０のＱ１，Ｒ１，Ｒ２直列回路の電圧Ｖｃ（つまりＱ１のコレクタ電圧）に対応する電圧を、コンデンサＣ１と抵抗Ｒ４のＣＲ並列回路を介して、比較器（オペアンプ）３１の＋入力に入力している。比較器３１の−入力には、抵抗Ｒ５，Ｒ６，Ｒ７及びツェナーダイオードＺ１からなる基準電圧発生回路で発生される比較基準電圧が入力される。すなわち、安定化電源回路１０の副電源出力ライン１２と接地ライン１３との間に抵抗Ｒ５，Ｒ６，Ｒ７の直列回路が接続され、抵抗Ｒ５とＲ６の接続点と接地ライン１３との間にツェナーダイオードＺ１が接続され、抵抗Ｒ６，Ｒ７の接続点が比較器３１の−入力に接続されている。これにより、定常状態において抵抗Ｒ５とＲ６の接続点の電圧はツェナーダイオードＺ１のツェナー電圧によって規定される一定電圧となり、この一定電圧を抵抗Ｒ６，Ｒ７で分圧した電圧が比較基準電圧として比較器３１の−入力に入力される。比較器３１の出力は、抵抗Ｒ８、ダイオードＤ１を介して、安定化電源回路１０に対してフィードバック信号ＦＢとして出力される。   The output voltage control circuit 30 supplies a feedback signal to the stabilized power supply circuit 10 so as to control the voltage Vc of the constant current circuit 20 to a predetermined constant voltage. Specifically, as shown in FIG. 2, a voltage corresponding to the voltage Vc (that is, the collector voltage of Q1) of the Q1, R1, R2 series circuit of the constant current circuit 20 is passed through a CR parallel circuit of a capacitor C1 and a resistor R4. Are input to the + input of a comparator (op-amp) 31. A comparison reference voltage generated by a reference voltage generation circuit including resistors R5, R6, R7 and a Zener diode Z1 is input to the negative input of the comparator 31. That is, a series circuit of resistors R5, R6, and R7 is connected between the sub power output line 12 and the ground line 13 of the stabilized power supply circuit 10, and a Zener is connected between the connection point of the resistors R5 and R6 and the ground line 13. The diode Z1 is connected, and the connection point of the resistors R6 and R7 is connected to the negative input of the comparator 31. Thereby, in the steady state, the voltage at the connection point of the resistors R5 and R6 becomes a constant voltage defined by the Zener voltage of the Zener diode Z1, and a voltage obtained by dividing the constant voltage by the resistors R6 and R7 is used as a comparison reference voltage. 31 is input to the-input. The output of the comparator 31 is output as a feedback signal FB to the stabilized power supply circuit 10 via the resistor R8 and the diode D1.

出力電圧制御回路３０の動作について説明する。比較器３１の＋入力に加わる定電流回路２０の電圧Ｖｃに対応する電圧が、比較器３１の−入力に入力される比較基準電圧よりも小さいときは、比較器３１の出力は０である。比較器３１の＋入力に加わる定電流回路２０の電圧Ｖｃに対応する電圧が、比較器３１の−入力に入力される比較基準電圧よりも大きくなると、比較器３１の出力からは所定のプラス電圧が出力される。比較器３１から出力されたプラス電圧のフィードバック信号ＦＢは、次に述べるように、安定化電源回路１０の主電源出力ライン１１の出力電圧＋Ｖを可変制御する（詳しくは、低下させる）ように、該安定化電源回路１０に対して供給される。   The operation of the output voltage control circuit 30 will be described. When the voltage corresponding to the voltage Vc of the constant current circuit 20 applied to the + input of the comparator 31 is smaller than the comparison reference voltage input to the − input of the comparator 31, the output of the comparator 31 is zero. When the voltage corresponding to the voltage Vc of the constant current circuit 20 applied to the + input of the comparator 31 becomes larger than the comparison reference voltage input to the − input of the comparator 31, a predetermined positive voltage is output from the output of the comparator 31. Is output. The positive voltage feedback signal FB output from the comparator 31 variably controls (specifically decreases) the output voltage + V of the main power supply output line 11 of the stabilized power supply circuit 10 as described below. It is supplied to the stabilized power circuit 10.

安定化電源回路１０は、ＬＥＤ直列回路２に対する主電源出力ライン１１の出力電圧＋Ｖをフィードバックして該フィードバックされた電圧が所定電圧を超えないように制御するものであり、かつ、この出力電圧＋Ｖのフィードバック経路に出力電圧制御回路３０から出力されるフィードバック信号ＦＢを追加することで、該フィードバック信号ＦＢの追加に応じて出力電圧＋Ｖを可変制御する（低下させる）。このように、フィードバック信号ＦＢに応じて出力電圧＋Ｖを可変制御する（低下させる）ことで、定電流回路２０の電圧Ｖｃを所定の定電圧に維持する。   The stabilized power supply circuit 10 feeds back the output voltage + V of the main power supply output line 11 to the LED series circuit 2 and controls the fed back voltage so as not to exceed a predetermined voltage, and this output voltage + V By adding the feedback signal FB output from the output voltage control circuit 30 to the feedback path, the output voltage + V is variably controlled (reduced) according to the addition of the feedback signal FB. In this way, the output voltage + V is variably controlled (reduced) in accordance with the feedback signal FB, thereby maintaining the voltage Vc of the constant current circuit 20 at a predetermined constant voltage.

詳しくは、図２に示すように、安定化電源回路１０は、主電源出力ライン１１と接地ライン１３との間に抵抗Ｒ９，Ｒ１０，Ｒ１１の直列回路を接続し、抵抗Ｒ１０，Ｒ１１の接続点をシャントレギュレータＩＣ２のリファレンスに入力している。これにより、通常は、主電源出力ライン１１の電圧＋ＶをＲ１１／（Ｒ９＋Ｒ１０＋Ｒ１１）の比で分圧した電圧ＶｒｒがシャントレギュレータＩＣ２のリファレンスに入力される。抵抗Ｒ９，Ｒ１０，Ｒ１１の直列回路は、主電源出力ライン１１の出力電圧＋Ｖをフィードバックするためのフィードバック経路を形成しており、シャントレギュレータＩＣ２は、該フィードバック経路を介してフィードバックされた電圧が所定電圧を超えないように制御するための比較手段として機能する。出力電圧制御回路３０から出力されるフィードバック信号ＦＢは、フィードバック経路における抵抗Ｒ１０，Ｒ１１の接続点に印加される。これにより、主電源出力ライン１１の電圧＋ＶをＲ１１／（Ｒ９＋Ｒ１０＋Ｒ１１）の比で分圧した電圧に出力電圧制御回路３０からのフィードバック信号ＦＢが追加（加算）され、加算された電圧がシャントレギュレータＩＣ２のリファレンスに入力される。   Specifically, as shown in FIG. 2, the stabilized power supply circuit 10 includes a series circuit of resistors R9, R10, and R11 connected between the main power supply output line 11 and the ground line 13, and a connection point between the resistors R10 and R11. Is input to the reference of the shunt regulator IC2. Thereby, normally, the voltage Vrr obtained by dividing the voltage + V of the main power supply output line 11 by the ratio of R11 / (R9 + R10 + R11) is input to the reference of the shunt regulator IC2. The series circuit of the resistors R9, R10, and R11 forms a feedback path for feeding back the output voltage + V of the main power supply output line 11, and the shunt regulator IC2 receives a voltage fed back through the feedback path. It functions as a comparison means for controlling so as not to exceed the voltage. The feedback signal FB output from the output voltage control circuit 30 is applied to the connection point of the resistors R10 and R11 in the feedback path. As a result, the feedback signal FB from the output voltage control circuit 30 is added (added) to the voltage obtained by dividing the voltage + V of the main power supply output line 11 by the ratio of R11 / (R9 + R10 + R11), and the added voltage is added to the shunt regulator IC2. Input to the reference.

シャントレギュレータＩＣ２のカソードには、抵抗Ｒ１２，Ｒ１３を介して副電源出力ライン１２からの直流電圧が電源電圧として印加され、アノードは接地ライン１３に接続される。抵抗Ｒ１３に並列にフォトカプラ１４の発光ダイオード１４ａが接続される。これにより、シャントレギュレータＩＣ２が導通（オン）するとき、フォトカプラ１４の発光ダイオード１４ａが点灯し、フォトトランジスタ１４ｂを導通する。安定化電源回路１０においては、通常知られているように、フォトカプラ１４のフォトトランジスタ１４ｂのオン・オフに応じてトランス１５（図１）に対するＡＣ電源の供給をスイッチング制御し、交直変換後の出力電圧（フィードバック経路を介してフィードバックされた電圧）が所定電圧を超えないように制御する。なお、安定化電源回路１０の構成それ自体は公知のものを用いてよいため、詳細説明を省略する。   A DC voltage from the sub power output line 12 is applied as a power supply voltage to the cathode of the shunt regulator IC2 via resistors R12 and R13, and an anode is connected to the ground line 13. A light emitting diode 14a of the photocoupler 14 is connected in parallel with the resistor R13. Thereby, when the shunt regulator IC2 is turned on (on), the light emitting diode 14a of the photocoupler 14 is turned on and the phototransistor 14b is turned on. In the stabilized power supply circuit 10, as is generally known, the supply of AC power to the transformer 15 (FIG. 1) is switched in accordance with the on / off state of the phototransistor 14 b of the photocoupler 14, and the AC / AC conversion is performed. Control is performed so that the output voltage (voltage fed back via the feedback path) does not exceed a predetermined voltage. Note that a well-known configuration may be used for the stabilized power supply circuit 10 and detailed description thereof is omitted.

安定化電源回路１０における定電圧制御動作について説明する。まず、出力電圧制御回路３０からのフィードバック信号ＦＢが０である場合について説明する。その場合は、従来より知られた安定化電源の定電圧制御動作と同様である。すなわち、主電源出力ライン１１の電圧＋ＶをＲ１１／（Ｒ９＋Ｒ１０＋Ｒ１１）の比で分圧した電圧ＶｒｒがシャントレギュレータＩＣ２の基準電圧より大きくなると、シャントレギュレータＩＣ２がオンし、フォトカプラ１４のフォトトランジスタ１４ｂをオンして交直変換後の出力電圧＋Ｖを下げるようにする。出力電圧＋Ｖの低下によってフィードバックされる電圧Ｖｒｒが基準電圧より低下するとシャントレギュレータＩＣ２がオフする。これにより、フィードバック経路における抵抗Ｒ１０，Ｒ１１の接続点からシャントレギュレータＩＣ２のリファレンスに入力される電圧ＶｒｒがシャントレギュレータＩＣ２の基準電圧を超えないように、主電源出力ライン１１の出力電圧＋Ｖが定電圧制御される。すなわち、出力電圧＋Ｖは、＋Ｖ＝「ＩＣ２の基準電圧」×（Ｒ９＋Ｒ１０＋Ｒ１１）／Ｒ１１となるように定電圧制御される。   The constant voltage control operation in the stabilized power supply circuit 10 will be described. First, the case where the feedback signal FB from the output voltage control circuit 30 is 0 will be described. In that case, it is the same as the constant voltage control operation of the stabilized power supply conventionally known. That is, when the voltage Vrr obtained by dividing the voltage + V of the main power supply output line 11 by the ratio of R11 / (R9 + R10 + R11) becomes larger than the reference voltage of the shunt regulator IC2, the shunt regulator IC2 is turned on, and the phototransistor 14b of the photocoupler 14 is turned on. Turn on to reduce the output voltage + V after AC / DC conversion. When the voltage Vrr fed back due to the decrease in the output voltage + V decreases below the reference voltage, the shunt regulator IC2 is turned off. Thereby, the output voltage + V of the main power supply output line 11 is a constant voltage so that the voltage Vrr input to the reference of the shunt regulator IC2 from the connection point of the resistors R10 and R11 in the feedback path does not exceed the reference voltage of the shunt regulator IC2. Be controlled. That is, the output voltage + V is controlled at a constant voltage so that + V = “IC2 reference voltage” × (R9 + R10 + R11) / R11.

出力電圧制御回路３０からのフィードバック信号ＦＢがプラス電圧である場合は、シャントレギュレータＩＣ２のリファレンスに入力される電圧Ｖｒｒは、主電源出力ライン１１の電圧＋ＶをＲ１１／（Ｒ９＋Ｒ１０＋Ｒ１１）の比で分圧した電圧に出力電圧制御回路３０からのフィードバック信号ＦＢを加算したものとなる。これにより、上記と同様に、シャントレギュレータＩＣ２のリファレンスに入力される電圧ＶｒｒがシャントレギュレータＩＣ２の基準電圧を超えないように、主電源出力ライン１１の出力電圧＋Ｖが制御されるのであるが、制御の結果得られる出力電圧＋Ｖの値は、フィードバック信号ＦＢが０の場合に比べて、フィードバック信号ＦＢのプラス電圧が出力電圧＋Ｖのフィードバック電圧に加算されている場合の方が、小さな値となる。すなわち、フィードバック信号ＦＢの追加に応じて出力電圧＋Ｖが低下するように可変制御されることになる。出力電圧＋Ｖの低下にともない、定電流回路２０が分担する電圧Ｖｃも低下し、比較器３１の＋入力に加わる電圧が低下する。これにより、比較器３１の＋入力に加わる定電流回路２０の電圧Ｖｃに対応する電圧が、比較器３１の−入力に入力される比較基準電圧よりも小さくなると、比較器３１の出力が０となり、出力電圧制御回路３０からのフィードバック信号ＦＢが０となる。こうして、定電流回路２０の電圧Ｖｃが、比較器３１の−入力に入力される比較基準電圧に対応する所定の定電圧になるように定電圧制御される。一方、フィードバック信号ＦＢが０になると、シャントレギュレータＩＣ２のリファレンスに入力される電圧Ｖｒｒが低下するので、シャントレギュレータＩＣ２はオフし、主電源出力ライン１１の出力電圧＋Ｖはその状態で安定し、低下した値の出力電圧＋Ｖを安定的に維持する。   When the feedback signal FB from the output voltage control circuit 30 is a positive voltage, the voltage Vrr input to the reference of the shunt regulator IC2 divides the voltage + V of the main power supply output line 11 by a ratio of R11 / (R9 + R10 + R11). The feedback signal FB from the output voltage control circuit 30 is added to the voltage. Thus, as described above, the output voltage + V of the main power supply output line 11 is controlled so that the voltage Vrr input to the reference of the shunt regulator IC2 does not exceed the reference voltage of the shunt regulator IC2. The value of the output voltage + V obtained as a result of the above is smaller when the plus voltage of the feedback signal FB is added to the feedback voltage of the output voltage + V than when the feedback signal FB is 0. That is, the output voltage + V is variably controlled so as to decrease in accordance with the addition of the feedback signal FB. As the output voltage + V decreases, the voltage Vc shared by the constant current circuit 20 also decreases, and the voltage applied to the + input of the comparator 31 decreases. As a result, when the voltage corresponding to the voltage Vc of the constant current circuit 20 applied to the + input of the comparator 31 becomes smaller than the comparison reference voltage input to the − input of the comparator 31, the output of the comparator 31 becomes 0. The feedback signal FB from the output voltage control circuit 30 becomes zero. Thus, the constant voltage control is performed so that the voltage Vc of the constant current circuit 20 becomes a predetermined constant voltage corresponding to the comparison reference voltage input to the negative input of the comparator 31. On the other hand, when the feedback signal FB becomes 0, the voltage Vrr input to the reference of the shunt regulator IC2 decreases, so the shunt regulator IC2 is turned off, and the output voltage + V of the main power supply output line 11 is stabilized and decreased in that state. The output voltage + V of the obtained value is stably maintained.

例えば、ＬＥＤ直列回路２において最大で５個のＬＥＤが接続できるように安定化電源回路２が設計されているとし、そのときの出力電圧＋Ｖが２０（Ｖ）、定電流値が１（Ａ）、ＬＥＤ１個当りの電圧降下Ｖｆが３（Ｖ）、定電流回路２０の電圧Ｖｃが５（ｖ）、とする。ＬＥＤ直列回路２のＬＥＤを４個に減らすと、ＬＥＤ直列回路２が分担する電圧が１２（ｖ）となり、定電流回路２０の電圧Ｖｃを５（ｖ）に維持するために、出力電圧＋Ｖが１７（Ｖ）に低下される。同様に、ＬＥＤ直列回路２のＬＥＤを３個にすると、ＬＥＤ直列回路２が分担する電圧が９（ｖ）となり、定電流回路２０の電圧Ｖｃを５（ｖ）に維持するために、出力電圧＋Ｖが１４（Ｖ）に低下される。また、ＬＥＤ直列回路２のＬＥＤを２個にすると、ＬＥＤ直列回路２が分担する電圧が６（ｖ）となり、定電流回路２０の電圧Ｖｃを５（ｖ）に維持するために、出力電圧＋Ｖが１１（Ｖ）に低下される。また、ＬＥＤ直列回路２のＬＥＤを１個にすると、ＬＥＤ直列回路２が分担する電圧が３（ｖ）となり、定電流回路２０の電圧Ｖｃを５（ｖ）に維持するために、出力電圧＋Ｖが８（Ｖ）に低下される。いずれの場合も、定電流回路２０の電圧Ｖｃは５（ｖ）、電流は１（Ａ）、であり、消費電力は最低の５（Ｗ）に維持される。従って、消費電力の無駄がなく、発熱の問題も生じない。   For example, it is assumed that the stabilized power supply circuit 2 is designed so that a maximum of five LEDs can be connected in the LED series circuit 2, and the output voltage + V at that time is 20 (V) and the constant current value is 1 (A). The voltage drop Vf per LED is 3 (V), and the voltage Vc of the constant current circuit 20 is 5 (v). When the number of LEDs in the LED series circuit 2 is reduced to four, the voltage shared by the LED series circuit 2 becomes 12 (v), and in order to maintain the voltage Vc of the constant current circuit 20 at 5 (v), the output voltage + V is Reduced to 17 (V). Similarly, when the number of LEDs in the LED series circuit 2 is three, the voltage shared by the LED series circuit 2 becomes 9 (v), and the output voltage is maintained in order to maintain the voltage Vc of the constant current circuit 20 at 5 (v). + V is reduced to 14 (V). Further, when the number of LEDs in the LED series circuit 2 is two, the voltage shared by the LED series circuit 2 becomes 6 (v), and the output voltage + V in order to maintain the voltage Vc of the constant current circuit 20 at 5 (v). Is reduced to 11 (V). When the LED series circuit 2 has one LED, the voltage shared by the LED series circuit 2 is 3 (v), and the voltage Vc of the constant current circuit 20 is maintained at 5 (v). Is reduced to 8 (V). In any case, the voltage Vc of the constant current circuit 20 is 5 (v), the current is 1 (A), and the power consumption is maintained at the minimum of 5 (W). Therefore, there is no waste of power consumption and no problem of heat generation occurs.

次に、ＬＥＤ直列回路２に直列に設けられたスイッチ３をオフからオンに切り替えたときの動作について説明する。安定化電源回路２の出力電圧＋Ｖは設計上定められた最大数のＬＥＤに対応する値で出力され、また、定電流回路２０のトランジスタＱ１のベース−エミッタはバイアスされているので、スイッチ３がオフからオンに切り替わると同時にＬＥＤ直列回路２及び定電流回路２０からなる直列回路に駆動電流ｉcが流れる。ここで、駆動電流ｉcが所定の定電流を超えようとすると、即座にシャントレギュレータＩＣ１がオンし、定電流制御がなされる。従って、定電流制御の動作時間遅れは問題にならない。また、このとき、サージ電流が発生したとしても、ＬＥＤ直列回路２に並列に設けられたコンデンサ４で吸収される。そして、ＬＥＤ直列回路２に設けられたＬＥＤの数に応じて、該ＬＥＤの数が少ない場合は、定電流回路２０の電圧Ｖｃは当初は一瞬大きな値を示すが、上述した出力電圧制御回路３０による定電圧制御動作によって、速やかに出力電圧＋Ｖを低下させて電圧Ｖｃを定電圧に制御する。 Next, an operation when the switch 3 provided in series in the LED series circuit 2 is switched from OFF to ON will be described. The output voltage + V of the stabilized power supply circuit 2 is output at a value corresponding to the maximum number of LEDs determined by design, and the base-emitter of the transistor Q1 of the constant current circuit 20 is biased. At the same time as switching from OFF to ON, a drive current ic flows through a series circuit including the LED series circuit 2 and the constant current circuit 20. Here, when the drive current ic tries to exceed a predetermined constant current, the shunt regulator IC1 is immediately turned on and constant current control is performed. Therefore, the operation time delay of the constant current control is not a problem. At this time, even if a surge current is generated, it is absorbed by the capacitor 4 provided in parallel with the LED series circuit 2. Then, depending on the number of LEDs provided in the LED series circuit 2, when the number of LEDs is small, the voltage Vc of the constant current circuit 20 initially shows a large value for a moment, but the output voltage control circuit 30 described above. By the constant voltage control operation by, the output voltage + V is quickly reduced to control the voltage Vc to a constant voltage.

なお、点灯／消灯制御用のスイッチ３を、点灯装置１の出力とＬＥＤ直列回路２との間に設けることは、本発明の必須の要素ではなく、どこに設けてもよい。また、スイッチ３を設けずに、ＡＣ電源に対するコンセントの抜き差しで点灯／消灯制御を行うものであってもよい。しかし、上記実施例のように、点灯／消灯制御用のスイッチ３を点灯装置１の出力とＬＥＤ直列回路２との間に設ければ、使い勝手がよくなるので、有利である。そのような使い勝手のよさは、本発明に係るＬＥＤ点灯装置１を採用することによって初めて実現されるものである。   In addition, providing the switch 3 for lighting / extinguishing control between the output of the lighting device 1 and the LED series circuit 2 is not an essential element of the present invention, and may be provided anywhere. Further, without providing the switch 3, the lighting / extinguishing control may be performed by plugging / unplugging the AC power supply. However, if the switch 3 for lighting / extinguishing control is provided between the output of the lighting device 1 and the LED series circuit 2 as in the above embodiment, it is advantageous because it is easy to use. Such ease of use is realized for the first time by adopting the LED lighting device 1 according to the present invention.

また、シャントレギュレータＩＣ１，ＩＣ２は、ＩＣ素子からなるものに限らず、オペアンプを比較器として用いた回路構成からなるものを用いてもよい。
また、安定化電源回路２の方式及び回路構成は図示したものに限らず、どのような方式及び回路構成を用いてもよい。 Further, the shunt regulators IC1 and IC2 are not limited to those composed of IC elements, but may be those composed of a circuit configuration using an operational amplifier as a comparator.
Further, the system and circuit configuration of the stabilized power supply circuit 2 are not limited to those illustrated, and any system and circuit configuration may be used.

本発明の一実施例に係るＬＥＤ点灯装置の回路図である。It is a circuit diagram of the LED lighting device which concerns on one Example of this invention. 図１における定電流回路及び出力電圧制御回路、並びに安定化電源回路の一部、を拡大して示す回路図である。FIG. 2 is an enlarged circuit diagram showing a constant current circuit, an output voltage control circuit, and a part of a stabilized power supply circuit in FIG. 1.

符号の説明Explanation of symbols

１ ＬＥＤ点灯装置
２ ＬＥＤ直列回路
３ スイッチ
４ コンデンサ
１０ 安定化電源回路
２０ 定電流回路
３０ 出力電圧制御回路
ＩＣ１，ＩＣ２ シャントレギュレータ DESCRIPTION OF SYMBOLS 1 LED lighting device 2 LED series circuit 3 Switch 4 Capacitor 10 Stabilized power supply circuit 20 Constant current circuit 30 Output voltage control circuit IC1, IC2 Shunt regulator

Claims (4)

１乃至複数のＬＥＤを直列接続したＬＥＤ直列回路に対して電力を供給するＬＥＤ点灯装置であって、
前記ＬＥＤ直列回路に直列接続され、該ＬＥＤ直列回路を流れる電流を所定の定電流に制御する定電流回路と、
前記ＬＥＤ直列回路に電力を供給する安定化電源回路であって、該ＬＥＤ直列回路に対する出力電圧をフィードバックして該フィードバックされた電圧が所定電圧を超えないように制御するものと、
前記定電流回路の電圧を所定の定電圧に制御するよう前記安定化電源回路にフィードバック信号を供給する出力電圧制御回路と
を備え、前記安定化電源回路では、前記出力電圧のフィードバック経路に前記出力電圧制御回路から供給される前記フィードバック信号を追加することで、該フィードバック信号の追加に応じて前記出力電圧を可変制御するようにしたことを特徴とするＬＥＤ点灯装置。 An LED lighting device for supplying power to an LED series circuit in which one or more LEDs are connected in series,
A constant current circuit connected in series to the LED series circuit and controlling a current flowing through the LED series circuit to a predetermined constant current;
A stabilized power supply circuit for supplying power to the LED series circuit, wherein the output voltage to the LED series circuit is fed back and controlled so that the fed back voltage does not exceed a predetermined voltage;
An output voltage control circuit for supplying a feedback signal to the stabilized power supply circuit so as to control the voltage of the constant current circuit to a predetermined constant voltage, and the output to the feedback path of the output voltage in the stabilized power supply circuit An LED lighting device characterized in that the output voltage is variably controlled according to the addition of the feedback signal by adding the feedback signal supplied from a voltage control circuit. 前記出力電圧制御回路は、前記定電流回路の電圧を取り出して基準電圧と比較する比較器を含み、該比較器の出力を前記フィードバック信号として前記安定化電源回路に供給し、
前記安定化電源回路は、前記出力電圧に対応するフィードバック電圧に前記出力電圧制御回路から供給される前記フィードバック信号を加算することで、修正したフィードバック電圧を生成する回路を含み、該修正したフィードバック電圧が前記所定電圧を超えないように前記出力電圧を可変制御することを特徴とする請求項１に記載のＬＥＤ点灯装置。 The output voltage control circuit includes a comparator that takes out the voltage of the constant current circuit and compares it with a reference voltage, and supplies the output of the comparator as the feedback signal to the stabilized power circuit.
The stabilized power supply circuit includes a circuit that generates a corrected feedback voltage by adding the feedback signal supplied from the output voltage control circuit to a feedback voltage corresponding to the output voltage, and the corrected feedback voltage The LED lighting device according to claim 1, wherein the output voltage is variably controlled so that the voltage does not exceed the predetermined voltage. 前記ＬＥＤ点灯装置の出力と前記ＬＥＤ直列回路との間に該ＬＥＤ直列回路に対する電力の供給を制御するスイッチを設けたことを特徴とする請求項１又は２に記載のＬＥＤ点灯装置。   The LED lighting device according to claim 1, wherein a switch for controlling power supply to the LED series circuit is provided between an output of the LED lighting device and the LED series circuit. 前記スイッチに直列かつ前記ＬＥＤ直列回路に並列にサージ吸収用コンデンサを設けたことを特徴とする請求項３に記載のＬＥＤ点灯装置。   The LED lighting device according to claim 3, wherein a surge absorbing capacitor is provided in series with the switch and in parallel with the LED series circuit.
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