JP2004273267A

JP2004273267A - Led lighting device

Info

Publication number: JP2004273267A
Application number: JP2003062133A
Authority: JP
Inventors: Hiroyuki Sako; 浩行迫; Norio Kanai; 教郎金井; Shigeaki Yamazaki; 茂章山崎; Shunsuke Shibata; 俊介柴田
Original assignee: Ikeda Electric Co Ltd; Matsushita Electric Works Ltd
Current assignee: Panasonic Electric Works Co Ltd; Panasonic Life Solutions Ikeda Electric Co Ltd
Priority date: 2003-03-07
Filing date: 2003-03-07
Publication date: 2004-09-30
Anticipated expiration: 2023-03-07
Also published as: JP4199567B2

Abstract

PROBLEM TO BE SOLVED: To provide an LED lighting device capable of dimming stably by using a dimmer of phase control type. SOLUTION: The LED lighting device comprises a triac TRC connected in series to a commercial alternate current power source AC, and having its ON phase angle controlled by the dimmer 3, a rectifying circuit DB for connecting a series circuit for the commercial alternate current power source AC and the triac TRC between the input terminals and for rectifying the alternate current voltage to a pulsating direct current voltage, a smoothing capacitor C0 for smoothing the output of the rectifying circuit DB, an LED lighting circuit 1 for lighting a plurality of LEDs, LD1-LD40 using the output of the smoothing capacitor C0 as a power source, a detection circuit 2 for detecting ON period of the triac TRC by detecting the output voltage of the rectifying circuit DB, and a transistor Tr1 for interrupting current supply to the LED lighting device 1 from the smoothing capacitor C0 for the OFF period of the triac TRC, based on the detection result of the detection circuit 2. COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、ＬＥＤ点灯装置に関するものである。
【０００２】
【従来の技術】
近年青色ＬＥＤの商品化によって白色の高輝度ＬＥＤが開発され、従来は主に表示などの用途で使用されていたＬＥＤが照明用途にも使用されつつある。
【０００３】
例えば数百個のＬＥＤを平面状に並べて、あたかも平面光源のような形状にモジュール化した器具が提供されており、道路の信号灯や、踏切の警報信号灯などの用途にも用いられている（例えば特許文献１参照）。
【０００４】
また白熱電球と置き換えることができるように、ＬＥＤをＥベースの口金を有する電球型の本体に実装し、ＬＥＤの点灯回路を口金部分に収納した電球形のＬＥＤ点灯装置も提供されている。
【０００５】
このような電球形のＬＥＤ点灯装置では、白熱電球を調光点灯させる場合によく利用される位相制御式の調光器と組み合わせて使用されることを考慮して、図１０に示すように、位相制御された交流電圧を整流した脈流の直流電圧を直接ＬＥＤ点灯回路１に供給する回路方式が多く用いられている。
【０００６】
本回路は、商用交流電源ＡＣに直列に接続されたトライアックＴＲＣと、入力端子間に商用交流電源ＡＣ及びトライアックＴＲＣの直列回路が接続されたダイオードブリッジのような整流回路ＤＢと、整流回路ＤＢの出力端子間に接続されたＬＥＤ点灯回路１とで構成される。またＬＥＤ点灯回路１は、整流回路ＤＢの出力端子間に電流制限用の抵抗Ｒ１を介して接続された発光ダイオードＬＤ１〜ＬＤ４の直列回路と、整流回路ＤＢの出力端子間に電流制限用の抵抗Ｒ２を介して接続された発光ダイオードＬＤ５〜ＬＤ８の直列回路とで構成される。
【０００７】
そして本回路では、図示しない調光器からのトリガ信号を受けてトライアックＴＲＣで商用交流電源ＡＣの電源電圧を位相制御した後、整流回路ＤＢで整流して得た脈流電圧Ｖ２を、発光ダイオードＬＤ１〜ＬＤ４及び抵抗Ｒ１の直列回路と、発光ダイオードＬＤ５〜ＬＤ８及び抵抗Ｒ２の直列回路にそのまま印加しており、発光ダイオードＬＤ１〜ＬＤ４に流れる電流は抵抗Ｒ１で、発光ダイオードＬＤ５〜ＬＤ８に流れる電流は抵抗Ｒ２でそれぞれ決定される。
【０００８】
ここで図１１（ａ）（ｂ）はトライアックＴＲＣにより位相制御を行っている場合の各部の波形図であり、同図（ａ）は整流回路ＤＢの出力電圧Ｖ２の波形図、同図（ｂ）は発光ダイオードＬＤ１〜ＬＤ８に流れる電流の波形図である。図１１（ａ）（ｂ）の波形はトライアックＴＲＣのオン位相角を脈流電圧のピーク付近（９０度）に設定した場合の波形であり、オン位相角を矢印Ａ又はＢの方向にずらすことで、発光ダイオードＬＤ１〜ＬＤ８への供給電流を変化させて調光点灯している。
【０００９】
【特許文献１】
特開２０００−１７３３０４号公報（第６頁−第８頁、及び、第５図、第６図）
【００１０】
【発明が解決しようとする課題】
上記構成のＬＥＤ点灯装置では、発光ダイオードＬＤ１〜ＬＤ８に流れる電流の波形が脈流波形となり（図１１（ｂ）参照）、また発光ダイオードＬＤ１〜ＬＤ８自身にもオン電圧があって、整流回路ＤＢの出力電圧Ｖ２がオン電圧以下になると点灯しなくなるので、脈流電圧Ｖ２の電圧値が低いところでは発光ダイオードＬＤ１〜ＬＤ８の点灯維持電圧Ｖ_ＯＮよりも低くなって発光ダイオードＬＤ１〜ＬＤ８が消灯してしまうという問題があった。
【００１１】
そのため発光ダイオードＬＤ１〜ＬＤ８に安定した直流電圧を印加できるように、整流回路ＤＢの出力電圧（脈流電圧）を平滑コンデンサで平滑し、平滑コンデンサで平滑した電圧を発光ダイオードＬＤ１〜ＬＤ８に印加することも考えられるが、この場合はトライアックＴＲＣのオフ期間にも平滑コンデンサの充電電荷によって発光ダイオードＬＤ１〜ＬＤ８に電流が流れることになる。したがって、平滑コンデンサの容量次第では、オン位相角が０度から９０度までの範囲で調光器のボリュームを回してトライアックＴＲＣの位相角を変化させたとしても、平滑コンデンサに充分な電荷が充電されているために発光ダイオードＬＤ１〜ＬＤ８に流れる電流が変化せず、その結果調光が行われなくなり、またトライアックＴＲＣのオン位相角が９０度から１８０度までの範囲では平滑コンデンサを充電しつつ、急激に調光制御してしまうから、不安定な調光になってしまうという問題があった。
【００１２】
本発明は上記問題点に鑑みて為されたものであり、その目的とするところは、位相制御式の調光器を用いて安定に調光することが可能なＬＥＤ点灯装置を提供することにある。
【００１３】
【課題を解決するための手段】
上記目的を達成するために、請求項１の発明では、交流電源に直列に接続され位相制御調光器によってオン位相角が制御される位相制御素子と、入力端子間に交流電源及び位相制御素子の直列回路が接続され、交流電圧を整流して脈流直流電圧に変換する整流回路と、整流回路の出力を平滑する平滑コンデンサと、平滑コンデンサの出力を電源として１乃至複数の発光ダイオードを点灯させるＬＥＤ点灯回路とを備えたＬＥＤ点灯回路において、位相制御素子によって位相制御された交流電圧を検出することで位相制御素子のオン期間を検出する検出手段と、検出手段の検出結果をもとに位相制御素子のオフ期間に平滑コンデンサからＬＥＤ点灯回路への電流供給を遮断する遮断手段とを設けて成ることを特徴とする。
【００１４】
請求項２の発明では、交流電源に直列に接続され位相制御調光器によってオン位相角が制御される位相制御素子と、入力端子間に交流電源及び位相制御素子の直列回路が接続され、交流電圧を整流して脈流直流電圧に変換する整流回路と、整流回路の出力を平滑する平滑コンデンサと、平滑コンデンサにより平滑された直流電圧をスイッチング素子でスイッチングすることによって所望の電圧値の直流電圧に降圧する直流電源回路と、直流電源回路の出力を電源として１乃至複数の発光ダイオードを点灯させるＬＥＤ点灯回路とを備えたＬＥＤ点灯回路において、直流電源回路の出力を上記１乃至複数の発光ダイオードのオン電圧と略同じ電圧とし、位相制御素子によって位相制御された交流電圧を検出することで位相制御素子のオン期間を検出する検出手段と、検出手段の検出結果をもとに位相制御素子のオフ期間に平滑コンデンサからＬＥＤ点灯回路への電流供給を遮断する遮断手段とを設けて成ることを特徴とする。
【００１５】
請求項３の発明では、請求項２の発明において、上記直流電源回路は、上記スイッチング素子及びそのドライブ回路をワンチップ化したインテリジェントパワーデバイスを用いて構成した非絶縁型のチョッパ・レギュレータであることを特徴とする。
【００１６】
請求項４の発明では、請求項２の発明において、上記直流電源回路は、絶縁トランスを用いて構成した１石式のスイッチング電源であることを特徴とする。
【００１７】
請求項５の発明では、請求項１〜４の何れか１つの発明において、上記遮断手段は平滑コンデンサとＬＥＤ点灯回路との間に接続されたスイッチ素子からなり、上記検出手段は、整流回路の出力端子間に接続された複数の抵抗の直列回路と、一端が複数の抵抗の接続点に接続されるとともに、他端がスイッチ素子の制御端子に接続されたトリガ素子からなり、整流回路の脈流出力を検出することで位相制御素子で位相制御された交流電圧を間接的に検出することを特徴とする。
【００１８】
請求項６の発明では、請求項１〜４の何れか１つの発明において、上記遮断手段は平滑コンデンサとＬＥＤ点灯回路との間に接続されたスイッチ素子からなり、上記検出手段は、整流回路の入力端子にアノードが接続されたダイオードと、当該ダイオードのカソードと整流回路の低電位側の出力端子との間に接続された複数の抵抗の直列回路と、一端が複数の抵抗の接続点に接続されるとともに、他端がスイッチ素子の制御端子に接続されたトリガ素子からなることを特徴とする。
【００１９】
請求項７の発明では、請求項１〜４の何れか１つの発明において、上記遮断手段は平滑コンデンサとＬＥＤ点灯回路との間に接続されたスイッチ素子からなり、上記検出手段は、整流回路の各入力端子にそれぞれアノードが接続されるとともにカソードが共通接続された一対のダイオードと、両ダイオードのカソードと整流回路の低電位側の出力端子との間に接続された複数の抵抗の直列回路と、一端が複数の抵抗の接続点に接続されるとともに、他端がスイッチ素子の制御端子に接続されたトリガ素子からなることを特徴とする。
【００２０】
請求項８の発明では、請求項１〜７の何れか１つの発明において、上記ＬＥＤ点灯回路は、発光ダイオードに流れる電流を略一定にするミラー回路構成の定電流回路を具備して成ることを特徴とする。
【００２１】
【発明の実施の形態】
本発明の実施の形態を図面に基づいて説明する。
【００２２】
（実施形態１）
本発明の実施形態１を図１〜図３に基づいて説明する。
【００２３】
図１は本実施形態のＬＥＤ点灯装置の回路図であり、本装置は商用交流電源ＡＣに直列に接続され位相制御式の調光器３からのトリガ信号によってオン位相角が制御されるトライアックＴＲＣと、入力端子間に商用交流電源ＡＣ及びトライアックＴＲＣの直列回路が接続されたダイオードブリッジのような整流回路ＤＢと、整流回路ＤＢの高電位側の出力端子にアノードが接続された逆流防止用のダイオードＤ１と、ダイオードＤ１のカソードと整流回路ＤＢの低電位側の出力端子との間に接続された平滑コンデンサＣ０と、整流回路ＤＢの低電位側の出力端子にエミッタが接続されたスイッチ素子としてのＮＰＮ形のトランジスタＴｒ１と、平滑コンデンサＣ０の両端間にトランジスタＴｒ１を介して接続されたＬＥＤ点灯回路１と、トライアックＴＲＣで位相制御された交流電圧を検出することによってトライアックＴＲＣのオン状態を検出し、検出信号をトランジスタＴｒ１の制御端（ベース）に与える検出回路２（検出手段）とを備える。尚、検出回路２では、トライアックＴＲＣで位相制御された交流電圧を直接検出する代わりに、その交流電圧を整流回路ＤＢで全波整流した脈流直流電圧を検出しており、脈流直流電圧からトライアックＴＲＣのオン期間を検出している。
【００２４】
またＬＥＤ点灯回路１は、トランジスタＴｒ１のコレクタに一端がそれぞれ接続された電流制限用の抵抗Ｒ１，Ｒ２と、ダイオードＤ１及びコンデンサＣ０の接続点と抵抗Ｒ１の他端との間に順方向に直列接続された２０個の発光ダイオードＬＤ１，ＬＤ２…ＬＤ２０と、ダイオードＤ１及びコンデンサＣ０の接続点と抵抗Ｒ２の他端との間に順方向に直列接続された２０個の発光ダイオードＬＤ２１，ＬＤ２２…ＬＤ４０とで構成される。
【００２５】
また図２は検出回路２の具体回路であり、整流回路ＤＢの出力端子間に接続された抵抗Ｒ１０，Ｒ１１の直列回路と、抵抗Ｒ１０，Ｒ１１の接続点に一端が接続されるとともに他端がトランジスタＴｒ１のベースに接続されたトリガ素子Ｔとで構成される。ここで整流回路ＤＢの出力端子に脈流電圧が発生して、抵抗Ｒ１０，Ｒ１１の接続点が所定のトリガレベルＶａを超えると、トリガ素子Ｔが導通して、トランジスタＴｒ１のベースに電圧が印加されて、トランジスタＴｒ１がオンになる（図３（ａ）（ｂ）参照）。而してトランジスタＴｒ１は、トライアックＴＲＣのオン期間にオンして発光ダイオードＬＤ１〜ＬＤ４０に電流を供給するとともに、トライアックＴＲＣのオフ期間にオフして発光ダイオードＬＤ１〜ＬＤ４０への電流供給を遮断する。つまりトランジスタＴｒ１により、検出回路２の検出結果をもとにトライアックＴＲＣのオフ期間に平滑コンデンサＣ０からＬＥＤ点灯回路１への電流供給を遮断する遮断手段が構成される。なお遮断手段としてトランジスタＴｒ１からなるスイッチ素子を用いているが、スイッチ素子をトランジスタに限定する趣旨のものではなく、ＦＥＴなどのスイッチ素子を用いても良いことは言うまでもない。
【００２６】
次に本装置の動作について簡単に説明する。本装置では商用交流電源ＡＣの交流電源電圧をトライアックＴＲＣで位相制御するとともに、位相制御された脈流の交流電圧を整流回路ＤＢで直流の脈流電圧に変換した後、平滑コンデンサＣ０で平滑して得た電圧を発光ダイオードＬＤ１〜ＬＤ４０に供給している。
【００２７】
そして本装置の特徴は平滑コンデンサＣ０に２０個分の発光ダイオードのオン電圧以上の電圧を発生させて、平滑コンデンサＣ０からＬＥＤ点灯回路１へ安定した直流電圧を供給しつつ、整流回路ＤＢの出力電圧を検出することによってトライアックＴＲＣのオン状態を検出し、トライアックＴＲＣのオフ時にはトランジスタＴｒ１をオフさせて、ＬＥＤ点灯回路１への供給電流を強制的にカットしている。図３（ａ）（ｂ）はトライアックＴＲＣにより位相制御を行っている場合の各部の波形図であり、同図（ａ）は整流回路ＤＢの出力電圧Ｖ２の波形図、同図（ｂ）は発光ダイオードＬＤ１〜ＬＤ４０に流れる電流の波形図である。図３（ａ）（ｂ）の波形はトライアックＴＲＣのオン位相角を脈流電圧のピーク付近（９０度）に設定した場合の波形であり、オン位相角を矢印Ａ又はＢの方向にずらすことで、発光ダイオードへの供給電流のパルス幅を変化させて調光点灯している。
【００２８】
つまりＬＥＤ点灯回路１には、平滑コンデンサＣ０によって安定化された直流電圧がトランジスタＴｒ１を介して印加されており、トランジスタＴｒ１のオン／オフに応じて発光ダイオードＬＤ１〜ＬＤ４０に流れる電流がオン／オフされるので、発光ダイオードＬＤ１〜ＬＤ４０に流れる電流は矩形波のパルス電流となって、トライアックＴＲＣのオン位相角に応じてパルス幅が変化する。したがって、トライアックＴＲＣの全位相角にわたって平滑コンデンサＣ０からＬＥＤ点灯回路１に安定した電圧を供給することができ、従来のＬＥＤ点灯装置のように発光ダイオードに印加する電圧がオン電圧（点灯維持電圧）よりも下がることがないから、ＬＥＤ点灯回路１に電流が供給される期間中発光ダイオードＬＤ１〜ＬＤ４０を点灯させることができる。
【００２９】
また本回路は、図１０に示す従来のＬＥＤ点灯装置において、ＬＥＤ点灯回路１と直列に接続されるトランジスタＴｒ１と、トライアックＴＲＣのオン期間を検出する検出回路２とを追加しただけで、検出回路２は図２に示すように２個の抵抗Ｒ１０，Ｒ１１とトリガ素子Ｔのみで構成できるので、大きなコストアップとなることはない。
【００３０】
尚、本実施形態では各２０個の発光ダイオードＬＤ１〜ＬＤ２０、ＬＤ２１〜ＬＤ４０をそれぞれ直列に接続し、発光ダイオードＬＤ１〜ＬＤ２０の直列回路と発光ダイオードＬＤ２１〜ＬＤ４０の直列回路を平滑コンデンサＣ０と並列に接続しているが、直列に接続する発光ダイオードの個数や、平滑コンデンサＣ０と並列に接続する発光ダイオードの直列回路の数を上記の数に限定する趣旨のものではなく、入力電圧に応じて適宜決定すれば良い。本実施形態では入力電圧が１００Ｖの場合に効率良く点灯するように発光ダイオードの接続数を２０個としている。また、平滑コンデンサＣ０と並列に接続する発光ダイオードの直列回路の数を２つにしているのは、平滑コンデンサＣ０の両端間に４０個の発光ダイオードＬＤ１〜ＬＤ４０を全て直列に接続すると、その内の１個がオープン破壊した場合に残りの発光ダイオードが全て不点になるが、本回路では平滑コンデンサＣ０の両端間に発光ダイオードＬＤ１〜ＬＤ２０の直列回路（系統１）と、発光ダイオードＬＤ２１〜ＬＤ４０の直列回路（系統２）とを並列に接続することで、４０個の内の１個がオープン破壊しても、一方の系統の発光ダイオードが不点になるだけで、他の系統の２０個の発光ダイオードが不点になるのを防止して、全ての発光ダイオードＬＤ１〜ＬＤ４０が不点になるのを防止している。
【００３１】
（実施形態２）
本発明の実施形態２を図４及び図５に基づいて説明する。
【００３２】
上述の実施形態１では検出回路２が整流回路ＤＢの出力側の脈流直流電圧Ｖ２を検出することによって、トライアックＴＲＣで位相制御された交流電圧を間接的に検出して、トライアックＴＲＣのオン期間を求めているのに対して、本実施形態では図４に示すように検出回路２が整流回路ＤＢの入力側の交流電圧Ｖ１を検出しており、トライアックＴＲＣで位相制御された交流電圧Ｖ１を直接検出することで、トライアックＴＲＣのオン期間を検出している。尚、検出回路２以外は実施形態１と同様であるので、共通する構成要素には同一の符号を付してその説明は省略する。
【００３３】
図５は本実施形態の具体例を示し、検出回路２を、整流回路ＤＢの各入力端子にそれぞれアノードが接続されるとともにカソードが共通接続された一対のダイオードＤ２，Ｄ３と、両ダイオードＤ２，Ｄ３のカソードに発生する電圧を検出することで交流電圧Ｖ２を検出して、トライアックＴＲＣのオン期間を検出する検出部２ａとで構成している。なお検出部２ａは図２に示すような回路構成を有し、ダイオードＤ２，Ｄ３のカソードと整流回路ＤＢの低電位側の出力端子との間に接続された抵抗Ｒ１０，Ｒ１１の直列回路と、抵抗Ｒ１０，Ｒ１１の接続点に一端が接続されるとともに他端がトランジスタＴｒ１のベースに接続されたトリガ素子Ｔとで構成される。
【００３４】
ここで検出回路２では、整流回路ＤＢの入力電圧をダイオードＤ２，Ｄ３で整流して、抵抗Ｒ１０，Ｒ１１の直列回路に印加しており、抵抗Ｒ１０，Ｒ１１の接続点が所定のトリガレベルＶａを超えると、トリガ素子Ｔが導通してトランジスタＴｒ１のベースに電圧が印加され、トランジスタＴｒ１がオンになる。而してトランジスタＴｒ１は、トライアックＴＲＣのオン期間にオンして発光ダイオードＬＤ１〜ＬＤ４０に電流を供給するとともに、トライアックＴＲＣのオフ期間にオフして発光ダイオードＬＤ１〜ＬＤ４０への電流供給を遮断する。
【００３５】
このように本実施形態においても、平滑コンデンサＣ０からＬＥＤ点灯回路１へ安定した直流電圧を供給しつつ、位相制御された交流電圧Ｖ１を検出することによってトライアックＴＲＣのオン状態を検出し、トライアックＴＲＣのオフ時にはトランジスタＴｒ１をオフさせて、ＬＥＤ点灯回路１への供給電流を強制的にカットしているので、発光ダイオードＬＤ１〜ＬＤ４０に流れる電流が矩形波のパルス電流となって、トライアックＴＲＣのオン位相角に応じてパルス幅が変化し、発光ダイオードＬＤ１〜ＬＤ４０を調光することができる。したがって、トライアックＴＲＣの全位相角にわたって平滑コンデンサＣ０からＬＥＤ点灯回路１に安定した電圧を供給することができ、従来のＬＥＤ点灯装置のように発光ダイオードに印加する電圧がオン電圧（点灯維持電圧）よりも下がることがないから、ＬＥＤ点灯回路１に電流が供給される期間中発光ダイオードＬＤ１〜ＬＤ４０を点灯させることができる。
【００３６】
尚、本実施形態では検出回路２によりトライアックＴＲＣで位相制御された交流電圧Ｖ１を検出しているので、整流回路ＤＢとは別に交流電圧を整流して検出部２ａに入力するためのダイオードＤ２，Ｄ３、もしくは絶縁する手段が必要になり、実施形態１のように整流回路ＤＢの出力側の直流電圧を検出すことで、位相制御された交流電圧Ｖ１を間接的に検出する方がコスト的には有利である。
【００３７】
（実施形態３）
本発明の実施形態３を図６〜図８に基づいて説明する。
【００３８】
上述した実施形態１では、整流回路ＤＢの出力を平滑コンデンサＣ０で平滑して、平滑コンデンサＣ０で平滑された直流電圧をＬＥＤ点灯回路１に印加しているのに対して、本実施形態では、ＬＥＤ点灯回路１に供給する電圧を発光ダイオードの個数に応じた電圧に設定するため、図６に示すように平滑コンデンサＣ０で平滑された直流電圧をスイッチング素子でスイッチングすることによって発光ダイオードのオン電圧と略同じ電圧まで降圧する直流電源回路４を設け、直流電源回路４の低電位側の出力端子にトランジスタＴｒ１のエミッタを接続し、直流電源回路４の高電位側の出力端子とトランジスタＴｒ１のコレクタとの間にＬＥＤ点灯回路１を接続している。尚、ＬＥＤ点灯回路１及び直流電源回路４以外は実施形態１と同様であるので、共通する構成要素には同一の符号を付して、その説明は省略する。
【００３９】
本実施形態ではＬＥＤ点灯回路１を、トランジスタＴｒ１のコレクタに一端がそれぞれ接続された電流制限用の抵抗Ｒ１，Ｒ２と、直流電源回路４の高電位側の出力端子と抵抗Ｒ１の他端との間に順方向に直列接続された１０個の発光ダイオードＬＤ１，ＬＤ２…ＬＤ１０と、直流電源回路４の高電位側の出力端子と抵抗Ｒ２の他端との間に順方向に直列接続された１０個の発光ダイオードＬＤ１１，ＬＤ１２…ＬＤ２０とで構成している。
【００４０】
通常、発光ダイオードＬＤ１〜ＬＤ２０のオン電圧は約２〜４Ｖであるから、ＬＥＤ点灯回路１全体でオン電圧が４（Ｖ／個）×１０（個）＝４０Ｖ程度となり、実施形態１に比べて低電圧に設定している。したがって、直流電源回路４では、商用交流電源ＡＣを位相制御した電圧を整流回路ＤＢで整流し、平滑コンデンサＣ０で平滑して得た電圧を約４０Ｖ付近に降圧することで、ＬＥＤ点灯回路１に発光ダイオードの個数に応じた電圧を供給できる。
【００４１】
尚、直流電源回路４の出力端子間に全ての発光ダイオードＬＤ１〜ＬＤ２０を直列接続した場合はその内の１個がオープン破壊すると、残りの発光ダイオードまで不点になるが、直流電源回路４の出力端子間に発光ダイオードＬＤ１〜ＬＤ１０の直列回路（系統１）と、発光ダイオードＬＤ１１〜ＬＤ２０の直列回路（系統２）とを並列接続しているので、２０個の発光ダイオードＬＤ１〜ＬＤ２の内の１個がオープン破壊しても、一方の系統の発光ダイオードが不点になるだけで、他の系統の１０個の発光ダイオードは点灯するので、全ての発光ダイオードＬＤ１〜ＬＤ２０が不点になるのを防止できる。
【００４２】
ところで、図７及び図８は直流電源回路４の具体回路を示し、図７の例ではインテリジェントパワーデバイス（以下、ＩＰＤ素子と言う）４ａと、抵抗Ｒ５と、コンデンサＣ１〜Ｃ３と、インダクタＬ１と、ダイオードＤ４，Ｄ５と、ツェナーダイオードＺＤ１とからなる非絶縁型のチョッパ・レギュレータで直流電源回路４を構成している。
【００４３】
ＩＰＤ素子４ａはスイッチング素子としてのパワーＭＯＳＦＥＴ及びそのドライブ回路をワンチップ化したもので、出力電圧をツェナーダイオードＺＤ１及びダイオードＤ４を介してコントロール端子Ｃにフィードバックしており、出力電圧が（Ｖ_ＺＤ＋Ｖ_ＣＳ）となるように、内部のドライブ回路によりパワーＭＯＳＦＥＴのオン／オフを制御している。但し、Ｖ_ＺＤはツェナーダイオードＺＤ１のツェナー電圧、Ｖ_ＣＳはＩＰＤ素子４ａのコントロール端子Ｃとソース端子Ｓとの間の電圧である。
【００４４】
本回路ではスイッチング素子とそのドライブ回路をワンチップ化したＩＰＤ素子４ａを用いているので、回路の小型化、低コスト化が図れるが、非絶縁型であるので安全性には注意が必要である。なお本回路ではスイッチング素子とそのドライブ回路をワンチップ化したＩＰＤ素子４ａを用いているが、ＩＰＤ素子４ａの代わりにＭＯＳＦＥＴなどのスイッチング素子を用いても良く、その場合は制御用の外付け部品が若干必要になる。
【００４５】
また図８の例ではＩＰＤ素子４ａと、絶縁トランスＴ１と、抵抗Ｒ６，Ｒ７と、コンデンサＣ４，Ｃ５と、フォトカプラＰＣ１と、ダイオードＤ６〜Ｄ８と、ツェナーダイオードＺＤ２，ＺＤ３とからなる１石式のフライバック方式のスイッチング電源で直流電源回路４を構成している。
【００４６】
本回路では、安全性を高めるために絶縁トランスＴ１を用いて入力側と出力側とを絶縁しており、絶縁された出力電圧をフォトカプラＰＣ１で検出して、ＩＰＤ素子のコントロール端子にフィードバックしている。なお本回路ではスイッチング素子とそのドライブ回路をワンチップ化したＩＰＤ素子４ａを用いているが、ＩＰＤ素子４ａの代わりにＭＯＳＦＥＴなどのスイッチング素子を用いても良く、その場合は制御用の外付け部品が若干必要になる。
【００４７】
尚本実施形態では実施形態１のＬＥＤ点灯装置に直流電源回路４を付加しているが、実施形態２において直流電源回路４を付加しても良く、上述と同様の効果が得られる。
【００４８】
（実施形態４）
本発明の実施形態４を図９に基づいて説明する。
【００４９】
本実施形態では、上述の実施形態３において、ＬＥＤ点灯回路１にミラー回路構成の定電流回路５を設けており、発光ダイオードＬＤ１〜ＬＤ４に流れる電流を略一定に制御している。尚、ＬＥＤ点灯回路１及び定電流回路５以外の構成は実施形態３と同様であるので、共通する構成要素には同一の符号を付して、その説明は省略する。
【００５０】
ＬＥＤ点灯回路１は、トランジスタＴｒ１のコレクタに一端がそれぞれ接続された電流制限用の抵抗Ｒ１，Ｒ２と、直流電源回路４の高電位側の出力端と抵抗Ｒ１の他端との間にトランジスタＴｒ３を介して順方向に直列接続された２個の発光ダイオードＬＤ１，ＬＤ２と、直流電源回路４の高電位側の出力端と抵抗Ｒ２の他端との間にトランジスタＴｒ４を介して順方向に直列接続された２個の発光ダイオードＬＤ３，ＬＤ４とで構成される。本回路では実施形態３に比べて発光ダイオードＬＤ１…の接続個数を更に少なくしており、直流電源回路４の出力電圧を４（Ｖ／個）×２（個）＝８（Ｖ）付近の低電圧に設定している。
【００５１】
そして、一般的に発光ダイオードＬＤ１…のオン電圧は順方向電圧Ｖｆのセンター値に対して２割は変動するので、順方向電圧Ｖｆが変動しても、発光ダイオードＬＤ１…に流れる電流が変化しないように定電流回路５を設けている。
【００５２】
定電流回路５は、直流電源回路４の高電位側の出力端に一端が接続された抵抗Ｒ８と、トランジスタＴｒ１のコレクタに一端が接続された抵抗Ｒ９と、コレクタ−ベース間が短絡されるとともに抵抗Ｒ８の他端と抵抗Ｒ９の他端との間にコレクタ−エミッタ間が接続されたトランジスタＴｒ２と、トランジスタＴｒ２とベース同士が共通接続されたトランジスタＴｒ３，Ｔｒ４と、からなるミラー電流回路で構成され、発光ダイオードＬＤ１〜ＬＤ４に流れる電流を略一定にしているので、発光ダイオードＬＤ１〜ＬＤ４を安定に点灯させることができる。
【００５３】
尚、本実施形態では実施形態３においてＬＥＤ点灯回路１に定電流回路５を付加しているが、実施形態１又は２においてＬＥＤ点灯回路１に定電流回路５を付加しても良く、上述と同様の効果が得られる。
【００５４】
【発明の効果】
上述のように、請求項１の発明は、交流電源に直列に接続され位相制御調光器によってオン位相角が制御される位相制御素子と、入力端子間に交流電源及び位相制御素子の直列回路が接続され、交流電圧を整流して脈流直流電圧に変換する整流回路と、整流回路の出力を平滑する平滑コンデンサと、平滑コンデンサの出力を電源として１乃至複数の発光ダイオードを点灯させるＬＥＤ点灯回路とを備えたＬＥＤ点灯回路において、位相制御素子によって位相制御された交流電圧を検出することで位相制御素子のオン期間を検出する検出手段と、検出手段の検出結果をもとに位相制御素子のオフ期間に平滑コンデンサからＬＥＤ点灯回路への電流供給を遮断する遮断手段とを設けて成ることを特徴とし、検出手段により位相制御素子のオン状態を検出し、検出手段の検出結果をもとに位相制御素子のオフ期間は遮断手段が平滑コンデンサからＬＥＤ点灯回路への電流供給を遮断しているので、位相制御素子のオン位相角に応じたパルス幅で発光ダイオードに電流を流して調光することができ、そのうえ平滑コンデンサの出力を１乃至複数の発光ダイオードのオン電圧以上として、平滑コンデンサの出力をＬＥＤ点灯回路に供給しているので、位相制御素子の全位相角にわたってＬＥＤ点灯回路に安定した電圧を供給できるから、位相制御式の調光器を用いて発光ダイオードを安定に調光できるという効果がある。
【００５５】
請求項２の発明は、交流電源に直列に接続され位相制御調光器によってオン位相角が制御される位相制御素子と、入力端子間に交流電源及び位相制御素子の直列回路が接続され、交流電圧を整流して脈流直流電圧に変換する整流回路と、整流回路の出力を平滑する平滑コンデンサと、平滑コンデンサにより平滑された直流電圧をスイッチング素子でスイッチングすることによって所望の電圧値の直流電圧に降圧する直流電源回路と、直流電源回路の出力を電源として１乃至複数の発光ダイオードを点灯させるＬＥＤ点灯回路とを備えたＬＥＤ点灯回路において、直流電源回路の出力を上記１乃至複数の発光ダイオードのオン電圧と略同じ電圧とし、位相制御素子によって位相制御された交流電圧を検出することで位相制御素子のオン期間を検出する検出手段と、検出手段の検出結果をもとに位相制御素子のオフ期間に平滑コンデンサからＬＥＤ点灯回路への電流供給を遮断する遮断手段とを設けて成ることを特徴とし、検出手段により位相制御素子のオン状態を検出し、検出手段の検出結果をもとに位相制御素子のオフ期間は遮断手段が平滑コンデンサからＬＥＤ点灯回路への電流供給を遮断しているので、位相制御素子のオン位相角に応じたパルス幅で発光ダイオードに電流を流して調光することができ、そのうえ直流電源回路は平滑コンデンサで平滑した電圧を１乃至複数の発光ダイオードのオン電圧と略同じ電圧まで降圧し、その出力ををＬＥＤ点灯回路に供給しているので、位相制御素子の全位相角にわたってＬＥＤ点灯回路に安定した電圧を供給できるから、位相制御式の調光器を用いて発光ダイオードを安定に調光できるという効果がある。
【００５６】
請求項３の発明は、請求項２の発明において、上記直流電源回路は、上記スイッチング素子及びそのドライブ回路をワンチップ化したインテリジェントパワーデバイスを用いて構成した非絶縁型のチョッパ・レギュレータであることを特徴とし、請求項２の発明と同様の効果を奏する。
【００５７】
請求項４の発明は、請求項２の発明において、上記直流電源回路は、絶縁トランスを用いて構成した１石式のスイッチング電源であることを特徴とし、請求項２の発明と同様の効果を奏する。
【００５８】
請求項５の発明は、請求項１〜４の何れか１つの発明において、上記遮断手段は平滑コンデンサとＬＥＤ点灯回路との間に接続されたスイッチ素子からなり、上記検出手段は、整流回路の出力端子間に接続された複数の抵抗の直列回路と、一端が複数の抵抗の接続点に接続されるとともに、他端がスイッチ素子の制御端子に接続されたトリガ素子からなり、整流回路の脈流出力を検出することで位相制御素子で位相制御された交流電圧を間接的に検出することを特徴とし、抵抗の接続点の電位がトリガ素子のトリガレベルを超えると、トリガ素子が導通してスイッチ素子がオンするので、位相制御素子のオン／オフに応じてスイッチ素子をオン／オフさせて、発光ダイオードを調光することができる。
【００５９】
請求項６の発明は、請求項１〜４の何れか１つの発明において、上記遮断手段は平滑コンデンサとＬＥＤ点灯回路との間に接続されたスイッチ素子からなり、上記検出手段は、整流回路の入力端子にアノードが接続されたダイオードと、当該ダイオードのカソードと整流回路の低電位側の出力端子との間に接続された複数の抵抗の直列回路と、一端が複数の抵抗の接続点に接続されるとともに、他端がスイッチ素子の制御端子に接続されたトリガ素子からなることを特徴とし、ダイオードで交流電圧を整流して複数の抵抗の直列回路に印加しており、抵抗の接続点の電位がトリガ素子のトリガレベルを超えると、トリガ素子が導通してスイッチ素子がオンするので、位相制御素子のオン／オフに応じてスイッチ素子をオン／オフさせて、発光ダイオードを調光することができる。
【００６０】
請求項７の発明は、請求項１〜４の何れか１つの発明において、上記遮断手段は平滑コンデンサとＬＥＤ点灯回路との間に接続されたスイッチ素子からなり、上記検出手段は、整流回路の各入力端子にそれぞれアノードが接続されるとともにカソードが共通接続された一対のダイオードと、両ダイオードのカソードと整流回路の低電位側の出力端子との間に接続された複数の抵抗の直列回路と、一端が複数の抵抗の接続点に接続されるとともに、他端がスイッチ素子の制御端子に接続されたトリガ素子からなることを特徴とし、ダイオードで交流電圧を整流して複数の抵抗の直列回路に印加しており、抵抗の接続点の電位がトリガ素子のトリガレベルを超えると、トリガ素子が導通してスイッチ素子がオンするので、位相制御素子のオン／オフに応じてスイッチ素子をオン／オフさせて、発光ダイオードを調光することができる。
【００６１】
請求項８の発明は、請求項１〜７の何れか１つの発明において、上記ＬＥＤ点灯回路は、発光ダイオードに流れる電流を略一定にするミラー回路構成の定電流回路を具備して成ることを特徴とし、定電流回路により発光ダイオードに流れる電流を略一定にすることで、発光ダイオードを安定して調光することができる。
【図面の簡単な説明】
【図１】実施形態１のＬＥＤ点灯装置のブロック回路図である。
【図２】同上の要部の回路図である。
【図３】同上の位相制御時の各部の波形図であり、（ａ）は整流器の出力電圧の波形図、（ｂ）は発光ダイオードに流れる電流の波形図である。
【図４】実施形態２のＬＥＤ点灯装置のブロック回路図である。
【図５】同上のブロック回路図である。
【図６】実施形態３のＬＥＤ点灯装置のブロック回路図である。
【図７】同上の直流電源回路の回路図である。
【図８】同上の別の直流電源回路の回路図である。
【図９】実施形態４のＬＥＤ点灯装置のブロック回路図である。
【図１０】従来のＬＥＤ点灯装置のブロック回路図である。
【図１１】同上の位相制御時の各部の波形図であり、（ａ）は整流器の出力電圧の波形図、（ｂ）は発光ダイオードに流れる電流の波形図である。
【符号の説明】
１ＬＥＤ点灯回路
２検出回路
３調光器
ＡＣ商用交流電源
Ｃ０平滑コンデンサ
ＤＢ整流回路
ＬＤ１〜ＬＤ４０発光ダイオード
ＴＲＣトライアック
Ｔｒ１トランジスタ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an LED lighting device.
[0002]
[Prior art]
In recent years, white high-brightness LEDs have been developed due to the commercialization of blue LEDs, and LEDs that have been conventionally used mainly for display and the like are now being used for illumination.
[0003]
For example, there are provided appliances in which hundreds of LEDs are arranged in a plane so as to be modularized into a shape like a flat light source, and are also used for applications such as road signal lights and level crossing warning signal lights (for example, Patent Document 1).
[0004]
In order to replace the lamp with an incandescent light bulb, a bulb-shaped LED lighting device in which an LED is mounted on a bulb-type main body having an E-base base and a lighting circuit of the LED is housed in the base is also provided.
[0005]
In such a bulb-shaped LED lighting device, considering that it is used in combination with a phase control type dimmer that is often used when dimming and lighting an incandescent bulb, as shown in FIG. A circuit system in which a pulsating DC voltage obtained by rectifying a phase-controlled AC voltage is directly supplied to the LED lighting circuit 1 is often used.
[0006]
This circuit includes a rectifier circuit DB such as a diode bridge having a triac TRC connected in series to the commercial AC power supply AC, a series circuit of the commercial AC power supply AC and the triac TRC connected between input terminals, and a rectifier circuit DB. And an LED lighting circuit 1 connected between the output terminals. The LED lighting circuit 1 includes a series circuit of light emitting diodes LD1 to LD4 connected between output terminals of the rectifier circuit DB via a current limiting resistor R1 and a current limiting resistor between the output terminals of the rectifier circuit DB. It is composed of a series circuit of light emitting diodes LD5 to LD8 connected via R2.
[0007]
In this circuit, after receiving a trigger signal from a dimmer (not shown) and controlling the phase of the power supply voltage of the commercial AC power supply AC by the triac TRC, the pulsating voltage V2 obtained by rectification by the rectification circuit DB is converted to a light emitting diode. The current is directly applied to the series circuit of LD1 to LD4 and the resistor R1 and the series circuit of the light emitting diodes LD5 to LD8 and the resistor R2. The current flowing through the light emitting diodes LD1 to LD4 is the resistor R1 and the current flowing through the light emitting diodes LD5 to LD8. Is determined by the resistor R2.
[0008]
Here, FIGS. 11A and 11B are waveform diagrams of respective parts when the phase control is performed by the triac TRC, and FIG. 11A is a waveform diagram of the output voltage V2 of the rectifier circuit DB, and FIG. () Is a waveform diagram of a current flowing through the light emitting diodes LD1 to LD8. 11A and 11B are waveforms when the ON phase angle of the triac TRC is set near the peak of the pulsating voltage (90 degrees), and the ON phase angle is shifted in the direction of arrow A or B. Thus, dimming lighting is performed by changing the supply current to the light emitting diodes LD1 to LD8.
[0009]
[Patent Document 1]
JP-A-2000-173304 (pages 6 to 8 and FIGS. 5 and 6)
[0010]
[Problems to be solved by the invention]
In the LED lighting device having the above-described configuration, the waveform of the current flowing through the light emitting diodes LD1 to LD8 becomes a pulsating waveform (see FIG. 11B). When the output voltage V2 becomes lower than the on-state voltage, the light is not turned on. Therefore, where the voltage value of the pulsating voltage V2 is low, the lighting sustaining voltage V of the light emitting diodes LD1 to LD8 is low. _ON And the light emitting diodes LD1 to LD8 are turned off.
[0011]
Therefore, the output voltage (pulsating current voltage) of the rectifier circuit DB is smoothed by a smoothing capacitor so that a stable DC voltage can be applied to the light emitting diodes LD1 to LD8, and the voltage smoothed by the smoothing capacitor is applied to the light emitting diodes LD1 to LD8. However, in this case, even in the OFF period of the triac TRC, a current flows through the light emitting diodes LD1 to LD8 due to the charge of the smoothing capacitor. Therefore, depending on the capacity of the smoothing capacitor, even if the phase angle of the triac TRC is changed by turning the volume of the dimmer in the range where the ON phase angle is in the range of 0 to 90 degrees, sufficient charge is charged in the smoothing capacitor. As a result, the current flowing in the light emitting diodes LD1 to LD8 does not change, and as a result, dimming is not performed. In addition, while the ON phase angle of the triac TRC is in the range of 90 degrees to 180 degrees, the smoothing capacitor is charged. However, there is a problem that the dimming control is suddenly performed, resulting in unstable dimming.
[0012]
The present invention has been made in view of the above problems, and an object of the present invention is to provide an LED lighting device capable of stably dimming using a phase control type dimmer. is there.
[0013]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the present invention, a phase control element connected in series to an AC power supply and having an ON phase angle controlled by a phase control dimmer, and an AC power supply and a phase control element between input terminals. A rectifier circuit that rectifies an AC voltage and converts it into a pulsating DC voltage, a smoothing capacitor that smoothes the output of the rectifier circuit, and turns on one or a plurality of light emitting diodes using the output of the smoothing capacitor as a power supply An LED lighting circuit comprising: an LED lighting circuit for detecting an AC voltage phase-controlled by the phase control element to detect an ON period of the phase control element; and And a cutoff means for cutting off the current supply from the smoothing capacitor to the LED lighting circuit during the off period of the phase control element.
[0014]
According to the second aspect of the present invention, a phase control element connected in series to an AC power supply and having an ON phase angle controlled by a phase control dimmer, and a series circuit of an AC power supply and a phase control element connected between input terminals, A rectifier circuit that rectifies the voltage to convert it into a pulsating DC voltage, a smoothing capacitor that smoothes the output of the rectifier circuit, and a DC voltage having a desired voltage value by switching the DC voltage smoothed by the smoothing capacitor with a switching element. An LED lighting circuit comprising: a DC power supply circuit for stepping down the voltage; and an LED lighting circuit for lighting one or more light emitting diodes using the output of the DC power supply as a power source. The ON voltage of the phase control element is set to be substantially the same as the ON voltage of the phase control element. Detection means for output, characterized by comprising a detection result of the detecting means provided with blocking means for blocking the supply of current from the smoothing capacitor based on the off-period of the phase control element to the LED lighting circuit.
[0015]
According to a third aspect of the present invention, in the second aspect of the present invention, the DC power supply circuit is a non-insulated chopper regulator configured by using an intelligent power device in which the switching element and its drive circuit are integrated into one chip. It is characterized by.
[0016]
According to a fourth aspect of the present invention, in the second aspect of the invention, the DC power supply circuit is a single-switch type switching power supply configured using an insulating transformer.
[0017]
According to a fifth aspect of the present invention, in any one of the first to fourth aspects of the present invention, the cutoff means includes a switch element connected between the smoothing capacitor and the LED lighting circuit, and the detection means includes a rectifier circuit. A series circuit of a plurality of resistors connected between output terminals, and a trigger element having one end connected to a connection point of the plurality of resistors and the other end connected to a control terminal of a switch element, and includes a pulse of a rectifier circuit. It is characterized in that an AC voltage phase-controlled by the phase control element is indirectly detected by detecting a current output.
[0018]
According to a sixth aspect of the present invention, in any one of the first to fourth aspects of the present invention, the shutoff means includes a switch element connected between the smoothing capacitor and the LED lighting circuit, and the detection means includes a rectifier circuit. A diode having an anode connected to the input terminal, a series circuit of a plurality of resistors connected between the cathode of the diode and the output terminal on the low potential side of the rectifier circuit, and one end connected to a connection point of the plurality of resistors And a trigger element having the other end connected to the control terminal of the switch element.
[0019]
According to a seventh aspect of the present invention, in any one of the first to fourth aspects of the present invention, the cutoff means includes a switch element connected between the smoothing capacitor and the LED lighting circuit, and the detection means includes a rectifier circuit. A pair of diodes each having an anode connected to each input terminal and a cathode connected in common, and a series circuit of a plurality of resistors connected between the cathodes of both diodes and a low potential side output terminal of the rectifier circuit; And a trigger element having one end connected to a connection point of the plurality of resistors and the other end connected to a control terminal of the switch element.
[0020]
According to an eighth aspect of the present invention, in any one of the first to seventh aspects, the LED lighting circuit includes a constant current circuit having a mirror circuit configuration for making a current flowing through the light emitting diode substantially constant. Features.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to the drawings.
[0022]
(Embodiment 1)
First Embodiment A first embodiment of the present invention will be described with reference to FIGS.
[0023]
FIG. 1 is a circuit diagram of an LED lighting device according to the present embodiment. This device is connected in series to a commercial AC power supply AC, and has a triac TRC whose ON phase angle is controlled by a trigger signal from a phase control type dimmer 3. A rectifier circuit DB such as a diode bridge in which a series circuit of a commercial AC power supply AC and a triac TRC is connected between input terminals; and a backflow prevention device in which an anode is connected to a high-potential side output terminal of the rectifier circuit DB. A diode D1, a smoothing capacitor C0 connected between the cathode of the diode D1 and the low-potential output terminal of the rectifier circuit DB, and a switch element having an emitter connected to the low-potential output terminal of the rectifier circuit DB An NPN-type transistor Tr1, an LED lighting circuit 1 connected between both ends of a smoothing capacitor C0 via the transistor Tr1, Detecting the ON state of the triac TRC by detecting the AC voltage phase-controlled by the acknowledgment TRC, and a detection circuit 2 (detecting means) for providing a detection signal to the control terminal of the transistor Tr1 (base). Note that, in the detection circuit 2, instead of directly detecting the AC voltage whose phase is controlled by the triac TRC, a pulsating DC voltage obtained by full-wave rectifying the AC voltage by the rectifier circuit DB is detected. The on period of the triac TRC is detected.
[0024]
The LED lighting circuit 1 is connected in series in the forward direction between the current limiting resistors R1 and R2 each having one end connected to the collector of the transistor Tr1 and the connection point between the diode D1 and the capacitor C0 and the other end of the resistor R1. LD20, and 20 light-emitting diodes LD21, LD22,..., LD40 connected in series in the forward direction between the connection point of the diode D1 and the capacitor C0 and the other end of the resistor R2. It is composed of
[0025]
FIG. 2 shows a specific circuit of the detection circuit 2, wherein one end is connected to a connection point between the resistors R10 and R11 connected between the output terminals of the rectifier circuit DB, and the other end is connected to the connection point between the resistors R10 and R11. A trigger element T connected to the base of the transistor Tr1. Here, when a pulsating voltage is generated at the output terminal of the rectifier circuit DB and the connection point of the resistors R10 and R11 exceeds a predetermined trigger level Va, the trigger element T conducts and a voltage is applied to the base of the transistor Tr1. As a result, the transistor Tr1 is turned on (see FIGS. 3A and 3B). The transistor Tr1 is turned on during the ON period of the triac TRC to supply current to the light emitting diodes LD1 to LD40, and is turned off during the off period of the triac TRC to cut off the current supply to the light emitting diodes LD1 to LD40. That is, the transistor Tr 1 constitutes a cutoff unit that cuts off current supply from the smoothing capacitor C 0 to the LED lighting circuit 1 during the OFF period of the triac TRC based on the detection result of the detection circuit 2. Although the switching element including the transistor Tr1 is used as the cutoff means, it is needless to say that the switching element is not limited to the transistor and a switching element such as an FET may be used.
[0026]
Next, the operation of the present apparatus will be briefly described. In this apparatus, the AC power supply voltage of the commercial AC power supply AC is phase-controlled by the triac TRC, and the phase-controlled pulsating AC voltage is converted into a DC pulsating voltage by the rectifier circuit DB, and then smoothed by the smoothing capacitor C0. The obtained voltage is supplied to the light emitting diodes LD1 to LD40.
[0027]
The feature of this device is that the smoothing capacitor C0 generates a voltage equal to or higher than the ON voltage of the 20 light emitting diodes, and supplies a stable DC voltage from the smoothing capacitor C0 to the LED lighting circuit 1 while outputting the output of the rectifier circuit DB. By detecting the voltage, the on-state of the triac TRC is detected. When the triac TRC is off, the transistor Tr1 is turned off to forcibly cut off the supply current to the LED lighting circuit 1. 3 (a) and 3 (b) are waveform diagrams of respective parts when the phase control is performed by the triac TRC. FIG. 3 (a) is a waveform diagram of the output voltage V2 of the rectifier circuit DB, and FIG. It is a wave form diagram of the electric current which flows into light emitting diode LD1-LD40. 3A and 3B are waveforms when the on-phase angle of the triac TRC is set near the peak of the pulsating voltage (90 degrees), and the on-phase angle is shifted in the direction of arrow A or B. Thus, dimming lighting is performed by changing the pulse width of the current supplied to the light emitting diode.
[0028]
That is, the DC voltage stabilized by the smoothing capacitor C0 is applied to the LED lighting circuit 1 via the transistor Tr1, and the current flowing through the light emitting diodes LD1 to LD40 is turned on / off according to the on / off of the transistor Tr1. Therefore, the current flowing through the light emitting diodes LD1 to LD40 becomes a rectangular pulse current, and the pulse width changes according to the ON phase angle of the triac TRC. Therefore, a stable voltage can be supplied from the smoothing capacitor C0 to the LED lighting circuit 1 over the entire phase angle of the triac TRC, and the voltage applied to the light emitting diode as in the conventional LED lighting device becomes an ON voltage (lighting maintenance voltage). Therefore, the light emitting diodes LD 1 to LD 40 can be turned on during the period when the current is supplied to the LED lighting circuit 1.
[0029]
Further, this circuit is different from the conventional LED lighting device shown in FIG. 10 only in that a transistor Tr1 connected in series with the LED lighting circuit 1 and a detection circuit 2 for detecting the ON period of the triac TRC are added. 2 can be composed of only two resistors R10 and R11 and a trigger element T as shown in FIG. 2, so that the cost does not increase significantly.
[0030]
In this embodiment, 20 light emitting diodes LD1 to LD20 and LD21 to LD40 are respectively connected in series, and a series circuit of the light emitting diodes LD1 to LD20 and a series circuit of the light emitting diodes LD21 to LD40 are connected in parallel with the smoothing capacitor C0. Although they are connected, the number of light emitting diodes connected in series and the number of series circuits of light emitting diodes connected in parallel with the smoothing capacitor C0 are not intended to be limited to the above numbers, and are appropriately determined according to the input voltage. You only have to decide. In this embodiment, the number of connected light emitting diodes is set to 20 so that the light is efficiently turned on when the input voltage is 100V. The reason why the number of light emitting diodes connected in parallel with the smoothing capacitor C0 is two is that if all 40 light emitting diodes LD1 to LD40 are connected in series between both ends of the smoothing capacitor C0, In the case where one of the light emitting diodes is broken open, all the remaining light emitting diodes become ineffective. In this circuit, a series circuit (system 1) of the light emitting diodes LD1 to LD20 and the light emitting diodes LD21 to LD40 are provided between both ends of the smoothing capacitor C0. Is connected in parallel with the series circuit (system 2), even if one of the 40 circuits is openly destroyed, only the light emitting diode of one of the systems becomes a point and the other 20 circuits of the other system are broken. Of the light emitting diodes LD1 to LD40 is prevented.
[0031]
(Embodiment 2)
Embodiment 2 of the present invention will be described with reference to FIGS.
[0032]
In the first embodiment, the detection circuit 2 indirectly detects the AC voltage phase-controlled by the triac TRC by detecting the pulsating DC voltage V2 on the output side of the rectifier circuit DB, and detects the ON period of the triac TRC. On the other hand, in the present embodiment, the detection circuit 2 detects the AC voltage V1 on the input side of the rectifier circuit DB as shown in FIG. By directly detecting, the ON period of the triac TRC is detected. The components other than the detection circuit 2 are the same as those of the first embodiment. Therefore, the same reference numerals are given to the same components, and the description will be omitted.
[0033]
FIG. 5 shows a specific example of the present embodiment, in which the detection circuit 2 includes a pair of diodes D2 and D3, each having an anode connected to each input terminal of the rectifier circuit DB and a common cathode, and both diodes D2 and D2. The AC voltage V2 is detected by detecting the voltage generated at the cathode of D3, and the detection unit 2a detects the ON period of the triac TRC. The detection unit 2a has a circuit configuration as shown in FIG. 2, and includes a series circuit of resistors R10 and R11 connected between the cathodes of the diodes D2 and D3 and the low-potential output terminal of the rectifier circuit DB. One end is connected to the connection point of the resistors R10 and R11, and the other end is formed of a trigger element T connected to the base of the transistor Tr1.
[0034]
Here, in the detection circuit 2, the input voltage of the rectifier circuit DB is rectified by the diodes D2 and D3 and is applied to the series circuit of the resistors R10 and R11, and the connection point of the resistors R10 and R11 has a predetermined trigger level Va. If it exceeds, the trigger element T conducts, a voltage is applied to the base of the transistor Tr1, and the transistor Tr1 turns on. The transistor Tr1 is turned on during the ON period of the triac TRC to supply current to the light emitting diodes LD1 to LD40, and is turned off during the off period of the triac TRC to cut off the current supply to the light emitting diodes LD1 to LD40.
[0035]
As described above, also in the present embodiment, the ON state of the triac TRC is detected by detecting the phase-controlled AC voltage V1 while supplying a stable DC voltage from the smoothing capacitor C0 to the LED lighting circuit 1, thereby detecting the triac TRC. When the transistor is turned off, the transistor Tr1 is turned off and the current supplied to the LED lighting circuit 1 is forcibly cut, so that the current flowing through the light emitting diodes LD1 to LD40 becomes a rectangular pulse current, and the triac TRC is turned on. The pulse width changes according to the phase angle, and the light emitting diodes LD1 to LD40 can be adjusted. Therefore, a stable voltage can be supplied from the smoothing capacitor C0 to the LED lighting circuit 1 over the entire phase angle of the triac TRC, and the voltage applied to the light emitting diode as in the conventional LED lighting device becomes an ON voltage (lighting maintenance voltage). Therefore, the light emitting diodes LD 1 to LD 40 can be turned on during the period when the current is supplied to the LED lighting circuit 1.
[0036]
In this embodiment, since the detection circuit 2 detects the AC voltage V1 whose phase is controlled by the triac TRC, the diode D2 for rectifying the AC voltage and inputting it to the detection unit 2a separately from the rectification circuit DB. D3 or an insulating means is required, and it is more cost effective to detect the phase-controlled AC voltage V1 indirectly by detecting the DC voltage on the output side of the rectifier circuit DB as in the first embodiment. Is advantageous.
[0037]
(Embodiment 3)
Embodiment 3 of the present invention will be described with reference to FIGS.
[0038]
In Embodiment 1 described above, the output of the rectifier circuit DB is smoothed by the smoothing capacitor C0, and the DC voltage smoothed by the smoothing capacitor C0 is applied to the LED lighting circuit 1, whereas in the present embodiment, In order to set the voltage supplied to the LED lighting circuit 1 to a voltage corresponding to the number of light emitting diodes, the DC voltage smoothed by the smoothing capacitor C0 is switched by a switching element as shown in FIG. A DC power supply circuit 4 for stepping down the voltage to substantially the same voltage as that of the DC power supply circuit 4. An emitter of the transistor Tr1 is connected to a low potential side output terminal of the DC power supply circuit 4; And the LED lighting circuit 1 is connected. The components other than the LED lighting circuit 1 and the DC power supply circuit 4 are the same as those in the first embodiment, and thus the same reference numerals are given to the same components, and the description thereof will be omitted.
[0039]
In this embodiment, the LED lighting circuit 1 includes a current limiting resistor R1, R2 having one end connected to the collector of the transistor Tr1, an output terminal on the high potential side of the DC power supply circuit 4, and the other end of the resistor R1. .., LD10 connected in series in the forward direction between the output terminal on the high potential side of the DC power supply circuit 4 and the other end of the resistor R2. The light emitting diodes LD11, LD12,..., LD20.
[0040]
Normally, the on-voltage of the light emitting diodes LD1 to LD20 is about 2 to 4 V, so that the on-voltage of the entire LED lighting circuit 1 is about 4 (V / piece) × 10 (pieces) = 40 V, compared to the first embodiment. Set to low voltage. Therefore, in the DC power supply circuit 4, the voltage obtained by phase-controlling the commercial AC power supply AC is rectified by the rectifier circuit DB, and the voltage obtained by smoothing the voltage with the smoothing capacitor C0 is reduced to about 40 V, thereby providing the LED lighting circuit 1 with the LED lighting circuit 1. A voltage corresponding to the number of light emitting diodes can be supplied.
[0041]
When all of the light-emitting diodes LD1 to LD20 are connected in series between the output terminals of the DC power supply circuit 4, if one of them is opened and destroyed, the remaining light-emitting diodes become infallible. Since a series circuit (system 1) of the light emitting diodes LD1 to LD10 and a series circuit (system 2) of the light emitting diodes LD11 to LD20 are connected in parallel between the output terminals, of the 20 light emitting diodes LD1 to LD2, Even if one of the light emitting diodes breaks open, only one of the light emitting diodes of one system becomes a point and the ten light emitting diodes of the other system are turned on, so that all the light emitting diodes LD1 to LD20 become a point. Can be prevented.
[0042]
7 and 8 show a specific circuit of the DC power supply circuit 4. In the example of FIG. 7, an intelligent power device (hereinafter referred to as an IPD element) 4a, a resistor R5, capacitors C1 to C3, and an inductor L1 are shown. , The diodes D4 and D5 and the zener diode ZD1 constitute the DC power supply circuit 4 with a non-insulated chopper regulator.
[0043]
The IPD element 4a is obtained by integrating a power MOSFET as a switching element and a drive circuit thereof into a single chip. The output voltage is fed back to the control terminal C via a Zener diode ZD1 and a diode D4. _ZD + V _CS ), The on / off of the power MOSFET is controlled by an internal drive circuit. Where V _ZD Is the Zener voltage of the Zener diode ZD1, V _CS Is a voltage between the control terminal C and the source terminal S of the IPD element 4a.
[0044]
This circuit uses the IPD element 4a in which the switching element and its drive circuit are integrated into one chip, so that the circuit can be reduced in size and cost. However, since it is a non-insulated type, it is necessary to pay attention to safety. . Although this circuit uses the IPD element 4a in which the switching element and its drive circuit are integrated into one chip, a switching element such as a MOSFET may be used instead of the IPD element 4a, in which case an external control component is used. Is required slightly.
[0045]
In the example of FIG. 8, a one-piece type including an IPD element 4a, an insulating transformer T1, resistors R6 and R7, capacitors C4 and C5, a photocoupler PC1, diodes D6 to D8, and Zener diodes ZD2 and ZD3. The DC power supply circuit 4 is constituted by the flyback type switching power supply.
[0046]
In this circuit, the input side and the output side are insulated by using an isolation transformer T1 in order to enhance safety. The insulated output voltage is detected by the photocoupler PC1 and fed back to the control terminal of the IPD element. ing. Although this circuit uses the IPD element 4a in which the switching element and its drive circuit are integrated into one chip, a switching element such as a MOSFET may be used instead of the IPD element 4a, in which case an external control component is used. Is required slightly.
[0047]
In this embodiment, the DC power supply circuit 4 is added to the LED lighting device of the first embodiment. However, the DC power supply circuit 4 may be added in the second embodiment, and the same effects as described above can be obtained.
[0048]
(Embodiment 4)
Embodiment 4 of the present invention will be described with reference to FIG.
[0049]
In the present embodiment, a constant current circuit 5 having a mirror circuit configuration is provided in the LED lighting circuit 1 in the above-described third embodiment, and the current flowing through the light emitting diodes LD1 to LD4 is controlled to be substantially constant. Since the configuration other than the LED lighting circuit 1 and the constant current circuit 5 is the same as that of the third embodiment, the same reference numerals are given to the same components, and the description thereof will be omitted.
[0050]
The LED lighting circuit 1 includes a current limiting resistor R1, R2 having one end connected to the collector of the transistor Tr1, and a transistor Tr3 connected between the output terminal on the high potential side of the DC power supply circuit 4 and the other end of the resistor R1. And two serially connected light emitting diodes LD1 and LD2 in the forward direction through the transistor Tr4 between the high-potential output terminal of the DC power supply circuit 4 and the other end of the resistor R2. It is composed of two connected light emitting diodes LD3 and LD4. In this circuit, the number of connected light emitting diodes LD1... Is further reduced as compared with the third embodiment, and the output voltage of the DC power supply circuit 4 is reduced to about 4 (V / piece) × 2 (pieces) = 8 (V). Voltage is set.
[0051]
Since the on-voltage of the light emitting diodes LD1 generally fluctuates by 20% with respect to the center value of the forward voltage Vf, the current flowing through the light emitting diodes LD1 does not change even if the forward voltage Vf fluctuates. Thus, the constant current circuit 5 is provided.
[0052]
The constant current circuit 5 includes a resistor R8 having one end connected to the output terminal on the high potential side of the DC power supply circuit 4, a resistor R9 having one end connected to the collector of the transistor Tr1, and a short circuit between the collector and the base. A mirror current circuit including a transistor Tr2 having a collector and an emitter connected between the other end of the resistor R8 and the other end of the resistor R9, and transistors Tr3 and Tr4 having a common connection between the transistor Tr2 and the base. Since the current flowing through the light emitting diodes LD1 to LD4 is substantially constant, the light emitting diodes LD1 to LD4 can be stably turned on.
[0053]
In the present embodiment, the constant current circuit 5 is added to the LED lighting circuit 1 in the third embodiment. However, the constant current circuit 5 may be added to the LED lighting circuit 1 in the first or second embodiment. Similar effects can be obtained.
[0054]
【The invention's effect】
As described above, a first aspect of the present invention is a series circuit of an AC power supply and a phase control element connected between an input terminal and a phase control element connected in series to an AC power supply and having an ON phase angle controlled by a phase control dimmer. Is connected, a rectifier circuit that rectifies an AC voltage and converts it into a pulsating DC voltage, a smoothing capacitor that smoothes the output of the rectifier circuit, and an LED lighter that lights one or more light emitting diodes using the output of the smoothing capacitor as a power supply. Detecting means for detecting an on-period of the phase control element by detecting an AC voltage phase-controlled by the phase control element, and a phase control element based on a detection result of the detection means. And a cut-off means for cutting off the current supply from the smoothing capacitor to the LED lighting circuit during the off period of the phase control element. During the off period of the phase control element based on the detection result of the detection means, the cutoff means cuts off the current supply from the smoothing capacitor to the LED lighting circuit. It is possible to dimm light by passing a current through the light emitting diode with a width, and furthermore, by setting the output of the smoothing capacitor to the ON voltage of one or more light emitting diodes or more and supplying the output of the smoothing capacitor to the LED lighting circuit. Since a stable voltage can be supplied to the LED lighting circuit over the entire phase angle of the control element, there is an effect that the light emitting diode can be stably dimmed using a phase control type dimmer.
[0055]
According to a second aspect of the present invention, a series circuit of an AC power supply and a phase control element is connected between an input terminal and a phase control element which is connected in series to an AC power supply and whose ON phase angle is controlled by a phase control dimmer. A rectifier circuit that rectifies the voltage to convert it into a pulsating DC voltage, a smoothing capacitor that smoothes the output of the rectifier circuit, and a DC voltage having a desired voltage value by switching the DC voltage smoothed by the smoothing capacitor with a switching element. An LED lighting circuit comprising: a DC power supply circuit for stepping down the voltage; and an LED lighting circuit for lighting one or more light emitting diodes using the output of the DC power supply as a power source. And the on-period of the phase control element is detected by detecting the AC voltage phase-controlled by the phase control element. And a cutoff means for cutting off the current supply from the smoothing capacitor to the LED lighting circuit during the off period of the phase control element based on the detection result of the detection means. The on-state of the control element is detected, and based on the detection result of the detection means, the off-state of the phase control element interrupts the supply of current from the smoothing capacitor to the LED lighting circuit. Dimming can be performed by supplying a current to the light emitting diode with a pulse width corresponding to the phase angle, and the DC power supply circuit reduces the voltage smoothed by the smoothing capacitor to a voltage substantially equal to the on voltage of one or more light emitting diodes. Since the output is supplied to the LED lighting circuit, a stable voltage can be supplied to the LED lighting circuit over the entire phase angle of the phase control element. There is an effect that can be stably dimming a light emitting diode using a dimmer.
[0056]
According to a third aspect of the present invention, in the second aspect of the present invention, the DC power supply circuit is a non-insulated chopper regulator configured using an intelligent power device in which the switching element and its drive circuit are integrated into one chip. And has the same effect as the second aspect of the invention.
[0057]
According to a fourth aspect of the present invention, in the second aspect of the present invention, the DC power supply circuit is a one-switch type switching power supply configured using an insulating transformer. Play.
[0058]
According to a fifth aspect of the present invention, in any one of the first to fourth aspects of the present invention, the blocking means includes a switch element connected between the smoothing capacitor and the LED lighting circuit, and the detecting means includes a rectifying circuit. A series circuit of a plurality of resistors connected between the output terminals, and a trigger element having one end connected to a connection point of the plurality of resistors and the other end connected to a control terminal of the switch element, It is characterized by indirectly detecting the AC voltage phase-controlled by the phase control element by detecting the current output.If the potential at the connection point of the resistor exceeds the trigger level of the trigger element, the trigger element conducts. Since the switching element is turned on, the light emitting diode can be dimmed by turning on / off the switching element in accordance with the on / off of the phase control element.
[0059]
According to a sixth aspect of the present invention, in any one of the first to fourth aspects of the present invention, the blocking means comprises a switch element connected between the smoothing capacitor and the LED lighting circuit, and the detecting means includes a rectifying circuit. A diode having an anode connected to the input terminal, a series circuit of a plurality of resistors connected between the cathode of the diode and the output terminal on the low potential side of the rectifier circuit, and one end connected to a connection point of the plurality of resistors And a trigger element having the other end connected to the control terminal of the switch element.The AC voltage is rectified by a diode and applied to a series circuit of a plurality of resistors. When the potential exceeds the trigger level of the trigger element, the trigger element conducts and the switch element turns on. Therefore, the switch element is turned on / off according to the on / off of the phase control element, and light emission is performed. Diode can be dimming.
[0060]
According to a seventh aspect of the present invention, in any one of the first to fourth aspects of the present invention, the blocking means includes a switch element connected between the smoothing capacitor and the LED lighting circuit, and the detecting means includes a rectifying circuit. A pair of diodes each having an anode connected to each input terminal and a cathode connected in common, and a series circuit of a plurality of resistors connected between the cathodes of both diodes and a low potential side output terminal of the rectifier circuit; , One end of which is connected to a connection point of a plurality of resistors, and the other end of which is formed of a trigger element connected to a control terminal of a switch element. When the potential at the connection point of the resistor exceeds the trigger level of the trigger element, the trigger element conducts and the switch element turns on, and the phase control element turns on / off. The switching elements are turned on / off, the light emitting diode can be the dimming in accordance with the.
[0061]
According to an eighth aspect of the present invention, in any one of the first to seventh aspects of the present invention, the LED lighting circuit includes a constant current circuit having a mirror circuit configuration for making a current flowing through the light emitting diode substantially constant. As a feature, the current flowing through the light emitting diode is made substantially constant by the constant current circuit, so that the light emitting diode can be stably dimmed.
[Brief description of the drawings]
FIG. 1 is a block circuit diagram of an LED lighting device according to a first embodiment.
FIG. 2 is a circuit diagram of a main part of the above.
FIGS. 3A and 3B are waveform diagrams of respective parts at the time of phase control according to the first embodiment; FIG. 3A is a waveform diagram of an output voltage of a rectifier; FIG.
FIG. 4 is a block circuit diagram of an LED lighting device according to a second embodiment.
FIG. 5 is a block circuit diagram of the same.
FIG. 6 is a block circuit diagram of an LED lighting device according to a third embodiment.
FIG. 7 is a circuit diagram of the DC power supply circuit according to the first embodiment;
FIG. 8 is a circuit diagram of another DC power supply circuit according to the first embodiment.
FIG. 9 is a block circuit diagram of an LED lighting device according to a fourth embodiment.
FIG. 10 is a block circuit diagram of a conventional LED lighting device.
FIGS. 11A and 11B are waveform diagrams of respective units at the time of phase control of the above, where FIG. 11A is a waveform diagram of an output voltage of a rectifier, and FIG. 11B is a waveform diagram of a current flowing through a light emitting diode.
[Explanation of symbols]
1 LED lighting circuit
2 Detection circuit
3 dimmer
AC commercial AC power supply
C0 Smoothing capacitor
DB rectifier circuit
LD1 to LD40 Light emitting diode
TRC triac
Tr1 transistor

Claims

A phase control element that is connected in series to an AC power supply and whose ON phase angle is controlled by a phase control dimmer, and a series circuit of the AC power supply and the phase control element are connected between the input terminals, rectify the AC voltage and pulsate the current. In an LED lighting circuit including a rectifier circuit for converting to a DC voltage, a smoothing capacitor for smoothing the output of the rectifier circuit, and an LED lighting circuit for lighting one or more light emitting diodes using the output of the smoothing capacitor as a power supply, Detecting means for detecting the on-period of the phase control element by detecting an AC voltage phase-controlled by the element; and, from the smoothing capacitor to the LED lighting circuit during the off-period of the phase control element based on the detection result of the detecting means. An LED lighting device comprising: a cutoff means for cutting off current supply.

A phase control element that is connected in series to an AC power supply and whose ON phase angle is controlled by a phase control dimmer, and a series circuit of the AC power supply and the phase control element are connected between the input terminals, rectify the AC voltage and pulsate the current. A rectifier circuit for converting to a DC voltage, a smoothing capacitor for smoothing the output of the rectifier circuit, and a DC power supply circuit for reducing the DC voltage smoothed by the smoothing capacitor to a DC voltage of a desired voltage value by switching the DC voltage with a switching element. And an LED lighting circuit for lighting one or more light emitting diodes using the output of the DC power supply circuit as a power supply, wherein the output of the DC power supply circuit is substantially the same as the ON voltage of the one or more light emitting diodes. And detecting means for detecting the ON period of the phase control element by detecting the AC voltage phase-controlled by the phase control element, Detecting means for detecting the result LED lighting apparatus characterized by comprising providing a cutoff unit for cutting off the supply of current from the smoothing capacitor based on the off-period of the phase control element to the LED lighting circuit.

3. The LED lighting device according to claim 2, wherein the DC power supply circuit is a non-insulated chopper regulator configured using an intelligent power device in which the switching element and its drive circuit are integrated into one chip.

The LED lighting device according to claim 2, wherein the DC power supply circuit is a one-switch type switching power supply configured using an insulating transformer.

The cutoff means includes a switch element connected between the smoothing capacitor and the LED lighting circuit. The detection means includes a series circuit of a plurality of resistors connected between output terminals of the rectifier circuit, and a plurality of resistors each having one end connected to the output terminal of the rectifier circuit. And a trigger element connected at the other end to the control terminal of the switch element. The AC voltage phase-controlled by the phase control element is indirectly detected by detecting the pulsating current output of the rectifier circuit. The LED lighting device according to any one of claims 1 to 4, wherein the detection is performed at the following timing.

The cutoff means includes a switch element connected between the smoothing capacitor and the LED lighting circuit. The detection means includes a diode having an anode connected to an input terminal of the rectifier circuit, and a cathode of the diode and a low voltage of the rectifier circuit. A series circuit of a plurality of resistors connected between the output terminal on the potential side and a trigger element having one end connected to a connection point of the plurality of resistors and the other end connected to a control terminal of the switch element The LED lighting device according to claim 1, wherein:

The blocking means comprises a switch element connected between the smoothing capacitor and the LED lighting circuit, and the detecting means comprises a pair of diodes each having an anode connected to each input terminal of the rectifier circuit and a cathode connected in common. A series circuit of a plurality of resistors connected between the cathodes of both diodes and a low potential side output terminal of the rectifier circuit, and one end connected to a connection point of the plurality of resistors, and the other end connected to a switch element The LED lighting device according to any one of claims 1 to 4, comprising a trigger element connected to the control terminal of (1).

The LED lighting device according to any one of claims 1 to 7, wherein the LED lighting circuit includes a constant current circuit having a mirror circuit configuration for making a current flowing through the light emitting diode substantially constant.