JP2010003810A - Light-emitting diode-driving circuit - Google Patents
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本発明は、発光ダイオード（Ｌｉｇｈｔ Ｅｍｉｔｔｉｎｇ Ｄｉｏｄｅ：ＬＥＤ）を用いた照明装置等における発光ダイオードの駆動回路に関するものである。 The present invention relates to a drive circuit for a light emitting diode in a lighting device or the like using a light emitting diode (LED).
従来より、白熱電球や蛍光灯と比べて消費電力の小さい発光ダイオードが照明装置に用いられている。通常、発光ダイオードは同じ製品でも内部抵抗にばらつきがあるため、輝度のばらつきを防止するために定電流回路を用いて点灯する。発光ダイオードは、使用しているうちに駆動回路の発熱などに起因して徐々に内部抵抗が上昇し、やがてオープン故障に至る。定電流回路では常に一定の電流が流れるため、発光ダイオードが劣化しオープン故障に至ることを阻止できなかった。 Conventionally, light emitting diodes that consume less power than incandescent bulbs and fluorescent lamps have been used in lighting devices. Usually, since the light emitting diodes have variations in internal resistance even in the same product, they are lit using a constant current circuit in order to prevent variations in luminance. As the light emitting diode is being used, the internal resistance gradually increases due to heat generated in the drive circuit, and eventually an open failure occurs. Since a constant current always flows in the constant current circuit, it was impossible to prevent the light emitting diode from deteriorating and causing an open failure.
特許文献１には、発光ダイオードがオープン故障したときに電流をバイパスさせる発光ダイオード照明装置が開示されている。
しかしながら、特許文献１のようなバイパス回路では発光ダイオードがオープン故障した後で電流をバイパスさせるのみで、直列に接続された他の発光ダイオードまで点灯しなくなることは防止できても、発光ダイオードのオープン故障自体を防止することはできなかった。 However, in the bypass circuit as in Patent Document 1, even if the current is bypassed only after the light emitting diode has an open failure, it is possible to prevent the other light emitting diodes connected in series from being turned off. The failure itself could not be prevented.
そこで、本発明は劣化の始まった発光ダイオードのオープン故障を未然に防止する発光ダイオード駆動回路を提供することを目的とする。 Accordingly, an object of the present invention is to provide a light emitting diode driving circuit that prevents an open failure of a light emitting diode that has started to deteriorate.
本発明は、電流が流れると発光する発光ダイオードと、前記発光ダイオードと並列に設けられ、予め設定した一定の電気抵抗を発生する並列回路と、前記発光ダイオードに流れる電流と前記並列回路に流れる電流との和が一定になるような電流を付与する定電流回路と、を備え、前記発光ダイオードの内部抵抗が大きくなると、前記並列回路に流れる電流の割合が大きくなり、相対的に前記発光ダイオードに流れる電流が減少することによって、前記発光ダイオードの負荷を低減することを特徴とする。 The present invention includes a light emitting diode that emits light when a current flows, a parallel circuit that is provided in parallel with the light emitting diode and generates a predetermined electric resistance, a current that flows through the light emitting diode, and a current that flows through the parallel circuit. And a constant current circuit for applying a current that makes the sum of the light emitting diode constant, and when the internal resistance of the light emitting diode increases, the ratio of the current flowing through the parallel circuit increases, and the light emitting diode relatively The load of the light emitting diode is reduced by reducing the flowing current.
本発明によれば、発光ダイオードが劣化して内部抵抗が増加してくると、発光ダイオードと並列に設けられ一定の電気抵抗を発生する並列回路に流れる電流の割合が大きくなり、発光ダイオードに流れる電流は減少する。よって、劣化した発光ダイオードに無理な電流を流すことはなく、発光ダイオードのオープン故障を未然に防止できる発光ダイオード駆動回路を得ることができる。 According to the present invention, when the light emitting diode deteriorates and the internal resistance increases, the ratio of the current flowing in the parallel circuit that is provided in parallel with the light emitting diode and generates a certain electric resistance increases and flows to the light emitting diode. The current decreases. Therefore, it is possible to obtain a light emitting diode driving circuit that can prevent an open failure of the light emitting diode without causing an excessive current to flow through the deteriorated light emitting diode.
以下、図面を参照しながら本発明の実施の形態に係る発光ダイオード駆動回路について説明する。 Hereinafter, a light emitting diode driving circuit according to an embodiment of the present invention will be described with reference to the drawings.
図１は本発明の実施の形態に係る発光ダイオード駆動回路の回路図、図２は発光ダイオードを駆動する定電流回路の一例の回路図である。 FIG. 1 is a circuit diagram of a light emitting diode driving circuit according to an embodiment of the present invention, and FIG. 2 is a circuit diagram of an example of a constant current circuit for driving the light emitting diode.
発光ダイオード駆動回路１００は、発光ダイオード１１と、発光ダイオード１１と並列に設けられる並列回路２０とを備える。 The light emitting diode drive circuit 100 includes a light emitting diode 11 and a parallel circuit 20 provided in parallel with the light emitting diode 11.
発光ダイオード１１は、順方向に電圧を印加すると発光する半導体素子である。発光ダイオード１１は可視光のみを発するため、白熱電球や蛍光灯のように赤外線を発光することによって発熱することはない。しかし、発光ダイオード１１の内部の配線や駆動回路は電流が流れることで発熱する。よって、発光ダイオード１１は使用を続けるうちに駆動回路等の発した熱によって徐々に劣化する。発光ダイオード１１の素子自体は半永久的に使用できるが、このように熱，衝撃，電極部分の劣化等によって内部の配線が断線し、いわゆるオープン故障の状態になって使用できなくなることがある。発光ダイオード１１は内部抵抗を有し、その内部抵抗は劣化と共に大きくなり、やがて内部の配線が断線すると内部抵抗は無限大になる。 The light emitting diode 11 is a semiconductor element that emits light when a voltage is applied in the forward direction. Since the light emitting diode 11 emits only visible light, it does not generate heat by emitting infrared rays unlike an incandescent bulb or a fluorescent lamp. However, the wiring and driving circuit inside the light emitting diode 11 generate heat when a current flows. Therefore, the light emitting diode 11 gradually deteriorates due to the heat generated by the drive circuit or the like while continuing to be used. Although the element of the light emitting diode 11 itself can be used semipermanently, the internal wiring may be disconnected due to heat, shock, deterioration of the electrode portion, and so on, so that it may become a so-called open failure state and cannot be used. The light-emitting diode 11 has an internal resistance, and the internal resistance increases with deterioration, and eventually the internal resistance becomes infinite when the internal wiring is disconnected.
発光ダイオード１１には、赤，緑，青などの可視光を発光するものや、赤外線，紫外線を発光するもの、又はこれらを組み合わせて白色に発光するものなどがある。発光ダイオード１１は、水銀等の有害物質を含有せず消費電力も小さいことから、白熱電球や蛍光灯に替えて用いられることが多い。 Examples of the light emitting diode 11 include those that emit visible light such as red, green, and blue, those that emit infrared rays and ultraviolet rays, and those that combine these to emit white light. Since the light emitting diode 11 does not contain harmful substances such as mercury and consumes little power, it is often used instead of an incandescent bulb or a fluorescent lamp.
並列回路２０は、発光ダイオード１１と並列に設けられ、予め設定した一定の電気抵抗を付与する回路である。並列回路２０は、二つのダイオード２１と抵抗器２２とを備える。 The parallel circuit 20 is a circuit that is provided in parallel with the light emitting diode 11 and applies a predetermined electric resistance. The parallel circuit 20 includes two diodes 21 and a resistor 22.
ダイオード２１は電流を片方向にしか流さない半導体素子である。ダイオード２１は電流を順方向へは流すが、整流作用によって電流を逆方向にはほとんど流さない。ダイオード２１は、並列に備えられた発光ダイオード１１と同じ方向にのみ電流を流す向きで配置される。ダイオード２１は、回路内で電流が逆流することを防止する。 The diode 21 is a semiconductor element that allows current to flow only in one direction. The diode 21 allows current to flow in the forward direction, but hardly allows current to flow in the reverse direction due to rectification. The diode 21 is arranged in a direction in which current flows only in the same direction as the light emitting diode 11 provided in parallel. The diode 21 prevents a current from flowing backward in the circuit.
抵抗器２２は、一定の電気抵抗により電気を流れにくくすることができる受動素子である。 The resistor 22 is a passive element that can make electricity difficult to flow due to a certain electric resistance.
本実施形態では、並列回路２０はダイオード２１を二つと抵抗器２２を一つ備えるが、この組み合わせに限られずダイオード２１の内部抵抗と抵抗器２２との合計が、設定した抵抗値になるようにすればよい。具体的には、ダイオード２１と抵抗器２２とを組み合わせた並列回路２０の全体としての抵抗値が、発光ダイオード１１の初期の内部抵抗値よりも大きな抵抗値になるように、ダイオード２１の個数や抵抗器２２の抵抗値の大きさを決定する。 In the present embodiment, the parallel circuit 20 includes two diodes 21 and one resistor 22. However, the present invention is not limited to this combination, and the total resistance of the internal resistance of the diode 21 and the resistor 22 becomes a set resistance value. do it. Specifically, the number of diodes 21 and the number of diodes 21 are set so that the overall resistance value of the parallel circuit 20 combining the diodes 21 and the resistors 22 is larger than the initial internal resistance value of the light emitting diodes 11. The resistance value of the resistor 22 is determined.
発光ダイオード１１と並列回路２０に付与される電流の和が一定になるように電流を供給する定電流回路２００は、オペアンプ５０とトランジスタ６０とを備える。図２のＲＬは負荷を意味し、本実施形態ではＲＬには発光ダイオード駆動回路１００が直列に多数設けられる。こうすることで多数の発光ダイオード１１を等しい電流で発光させることができる。 A constant current circuit 200 that supplies current so that the sum of currents applied to the light emitting diode 11 and the parallel circuit 20 is constant includes an operational amplifier 50 and a transistor 60. RL in FIG. 2 means a load. In this embodiment, a number of light emitting diode drive circuits 100 are provided in series in the RL. By doing so, a large number of light emitting diodes 11 can be made to emit light with an equal current.
負荷ＲＬに流れる出力電流Ｉｃは抵抗器Ｒ１を通じてアースされる。つまり、オペアンプ５０の−（マイナス）端子にはＩｃ×Ｒ１の電圧が生じ、この電圧とオペアンプ５０の＋（プラス）端子の電圧とが等しくなるようにオペアンプ５０が動作する。よって、電気抵抗の大きさが変化しても常に一定の電流がこの回路には流れることとなる。 The output current Ic flowing through the load RL is grounded through the resistor R1. That is, a voltage of Ic × R1 is generated at the − (minus) terminal of the operational amplifier 50, and the operational amplifier 50 operates so that this voltage is equal to the voltage of the + (plus) terminal of the operational amplifier 50. Therefore, a constant current always flows through this circuit even if the magnitude of the electrical resistance changes.
オペアンプ５０は、＋（プラス：非反転入力）と−（マイナス：反転入力）との二つの入力と一つの出力を備え、二つの入力間の電位差によって動作する差動増幅回路である。 The operational amplifier 50 is a differential amplifier circuit that has two inputs of + (plus: non-inverting input) and-(minus: inverting input) and one output, and operates by a potential difference between the two inputs.
トランジスタ６０は、増幅やスイッチの役割を果たす半導体素子である。トランジスタ６０にベース電流が流れると、それがスイッチとなり大きな出力電流Ｉｃが流れる。本実施形態ではトランジスタ６０にＮＰＮ型のバイポーラトランジスタを用いたが、ジャンクション型のＦＥＴ（電界効果トランジスタ）を用いてもよい。ジャンクション型のＦＥＴを用いた場合には、出力電流Ｉｃがベース電流分だけ少なくなることを防止できる。 The transistor 60 is a semiconductor element that plays the role of amplification and switching. When a base current flows through the transistor 60, it becomes a switch and a large output current Ic flows. In this embodiment, an NPN-type bipolar transistor is used as the transistor 60, but a junction-type FET (field effect transistor) may be used. When the junction type FET is used, it is possible to prevent the output current Ic from being reduced by the base current.
通常、発光ダイオード１１を駆動する場合には定電流回路２００のように流れる電流を一定に保つ定電流回路が用いられる。例えば白色発光ダイオードについて考えてみると、白色発光ダイオードの順方向電圧Ｖｆは、他の色の光を発する発光ダイオードと比して高く、Ｖｆ＝３．６Ｖ程度である。この順方向電圧は、それぞれの白色発光ダイオードで個体差があり全く同じ値ではないため、同じだけの電圧を印加しても同じように発光しない場合がある。そこで白色発光ダイオードを直列に接続して、それを定電流回路で駆動する方法が用いられる。 Normally, when driving the light emitting diode 11, a constant current circuit that keeps the flowing current constant, such as the constant current circuit 200, is used. For example, when considering a white light emitting diode, the forward voltage Vf of the white light emitting diode is higher than that of the light emitting diode emitting light of other colors, and is about Vf = 3.6V. This forward voltage has individual differences among the white light emitting diodes and is not exactly the same value. Therefore, even if the same voltage is applied, the forward voltage may not be emitted in the same manner. Therefore, a method of connecting white light emitting diodes in series and driving them with a constant current circuit is used.
定電流回路２００は、オペアンプ５０を用いた吸い込み型の定電流回路である。しかし、この形態に限られず吐き出し型の定電流回路やトランジスタを利用した定電流回路を用いてもよい。 The constant current circuit 200 is a suction type constant current circuit using the operational amplifier 50. However, the present invention is not limited to this configuration, and a discharge type constant current circuit or a constant current circuit using a transistor may be used.
以下では、本発明の実施の形態に係る発光ダイオード駆動回路１００の動作を説明する。 Hereinafter, the operation of the light emitting diode driving circuit 100 according to the embodiment of the present invention will be described.
定電流回路２００から電流が流されると、抵抗値の小さい発光ダイオード１１側の回路に多く電流が流れる。発光ダイオード１１は、電流が流れることによって固有の色に発光する。 When a current flows from the constant current circuit 200, a large amount of current flows through the circuit on the light emitting diode 11 side having a small resistance value. The light emitting diode 11 emits light in a unique color when a current flows.
発光ダイオード１１と並列に設けられ、ダイオード２１と抵抗器２２とを備える並列回路２０に流れる電流は、発光ダイオード１１の内部抵抗が小さなうちは少ないが、発光ダイオード１１の劣化により発光ダイオード１１の内部抵抗が大きくなってくると徐々に増加する。それに伴い、発光ダイオード１１に流れる電流は徐々に減少する。そうなると、発光ダイオード１１自体に流れる電流は劣化する前よりも少なくなるため、その発光の輝度は低くなる。しかし、発光ダイオード１１には無理に大きな電流を流さないため、オープン故障に至る可能性はそのまま大きな電流を流し続けた場合よりも低くなる。発光ダイオード１１がやがてオープン故障に至っても、そこで電流の流れが断たれることはなく、並列回路２０に全ての電流が流れるため、直列に接続された他の発光ダイオード１１の発光までも阻害することはない。 The current flowing through the parallel circuit 20 provided in parallel with the light emitting diode 11 and including the diode 21 and the resistor 22 is small while the internal resistance of the light emitting diode 11 is small. As resistance increases, it gradually increases. Along with this, the current flowing through the light emitting diode 11 gradually decreases. As a result, the current flowing through the light emitting diode 11 itself becomes smaller than before the deterioration, and the luminance of the light emission becomes low. However, since a large current is not forced to flow through the light emitting diode 11, the possibility of an open failure is lower than when a large current is continued to flow. Even if the light emitting diode 11 eventually reaches an open failure, the current flow is not interrupted there, and all the current flows through the parallel circuit 20, so that even the light emission of other light emitting diodes 11 connected in series is obstructed. There is nothing.
以上の実施の形態によれば、以下の効果を奏する。 According to the above embodiment, the following effects are produced.
発光ダイオード１１が劣化して内部抵抗が増加してくると、並列に設けられたダイオード２１と抵抗器２２とを備える回路に流れる電流の割合が大きくなり、発光ダイオード１１に流れる電流は減少する。よって、劣化した発光ダイオード１１に無理な電流を流すことはなく、発光ダイオード１１のオープン故障を未然に防止でき、発光ダイオード１１を長寿命にする発光ダイオード駆動回路を得ることができる。 When the light emitting diode 11 deteriorates and the internal resistance increases, the ratio of the current flowing through the circuit including the diode 21 and the resistor 22 provided in parallel increases, and the current flowing through the light emitting diode 11 decreases. Therefore, an unreasonable current is not passed through the deteriorated light emitting diode 11, an open failure of the light emitting diode 11 can be prevented in advance, and a light emitting diode drive circuit that extends the life of the light emitting diode 11 can be obtained.
例えば、内照式看板は一般に高い場所に取り付けられており、内部に設けられた照明ユニットを交換することは困難である。しかし、本発明に係る発光ダイオード駆動回路１００を内照式看板の照明ユニットに用いた場合には、発光ダイオード１１の交換の回数を減らすことができる。 For example, an internally illuminated signboard is generally mounted at a high place, and it is difficult to replace a lighting unit provided inside. However, when the light emitting diode driving circuit 100 according to the present invention is used in an illumination unit for an internally illuminated signboard, the number of replacements of the light emitting diodes 11 can be reduced.
このように、本発明に係る発光ダイオード駆動回路１００は発光ダイオード１１の交換が困難であるなど、交換の回数を少なくしたい場合に用いることが有効である。 As described above, it is effective to use the light emitting diode driving circuit 100 according to the present invention when it is desired to reduce the number of times of replacement such as the replacement of the light emitting diode 11 is difficult.
本発明は上記の実施の形態に限定されずに、その技術的な思想の範囲内において種々の変更がなしうることは明白である。 The present invention is not limited to the above-described embodiment, and it is obvious that various modifications can be made within the scope of the technical idea.
本発明に係る発光ダイオード駆動回路は、照明装置など発光ダイオードを用いる機器に利用することができる。 The light emitting diode driving circuit according to the present invention can be used for an apparatus using a light emitting diode such as a lighting device.
１００ 発光ダイオード駆動回路
１１ 発光ダイオード
２０ 並列回路
２１ ダイオード
２２ 抵抗器
５０ オペアンプ
６０ トランジスタ
２００ 定電流回路
DESCRIPTION OF SYMBOLS 100 Light emitting diode drive circuit 11 Light emitting diode 20 Parallel circuit 21 Diode 22 Resistor 50 Operational amplifier 60 Transistor 200 Constant current circuit
Claims (2)
前記発光ダイオードと並列に設けられ、予め設定した一定の電気抵抗を発生する並列回路と、
前記発光ダイオードに流れる電流と前記並列回路に流れる電流との和が一定になるような電流を付与する定電流回路と、
を備え、
前記発光ダイオードの内部抵抗が大きくなると、前記並列回路に流れる電流の割合が大きくなり、相対的に前記発光ダイオードに流れる電流が減少することによって、前記発光ダイオードの負荷を低減することを特徴とする発光ダイオード駆動回路。 A light emitting diode that emits light when a current flows;
A parallel circuit that is provided in parallel with the light emitting diode and generates a predetermined electrical resistance;
A constant current circuit for applying a current such that a sum of a current flowing through the light emitting diode and a current flowing through the parallel circuit is constant;
With
When the internal resistance of the light emitting diode increases, the ratio of the current flowing through the parallel circuit increases, and the current flowing through the light emitting diode relatively decreases, thereby reducing the load of the light emitting diode. Light emitting diode drive circuit.
前記ダイオードと直列に設けられ、一定の電気抵抗を付与する抵抗器と、
を備えることを特徴とする請求項１に記載の発光ダイオード駆動回路。 The parallel circuit includes a diode that allows current to flow only in the same direction as the light emitting diode;
A resistor provided in series with the diode to provide a certain electrical resistance;
The light emitting diode drive circuit according to claim 1, further comprising:
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2012178559A (en) * | 2011-02-11 | 2012-09-13 | Tai-Her Yang | Led device |
| US8879010B2 (en) | 2010-01-24 | 2014-11-04 | Semiconductor Energy Laboratory Co., Ltd. | Display device |
| US9064452B2 (en) | 2012-03-19 | 2015-06-23 | Samsung Display Co., Ltd. | Organic light emitting diode display |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02272778A (en) * | 1989-04-13 | 1990-11-07 | Sharp Corp | Driving circuit for optical semiconductor element |
| JPH10256610A (en) * | 1997-01-10 | 1998-09-25 | Rohm Co Ltd | Semiconductor light emitting device |
| JPH11307815A (en) * | 1998-04-23 | 1999-11-05 | Abikkusu Kk | Collective led lamp for ac power source |
| JP2006228904A (en) * | 2005-02-16 | 2006-08-31 | Sanken Electric Co Ltd | Compound semiconductor device |
| JP2007165161A (en) * | 2005-12-15 | 2007-06-28 | Sharp Corp | Led illumination device, led backlight device, and image display device |
| JP2007295758A (en) * | 2006-04-26 | 2007-11-08 | Denso Corp | Surge protector |
| JP2007324355A (en) * | 2006-05-31 | 2007-12-13 | Sony Corp | Light-emitting-diode lighting circuit, illuminating device, and liquid-crystal display device |
| JP2008130989A (en) * | 2006-11-24 | 2008-06-05 | Matsushita Electric Works Ltd | Led lighting circuit, and luminaire using the same |
-
2008
- 2008-06-19 JP JP2008160433A patent/JP2010003810A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02272778A (en) * | 1989-04-13 | 1990-11-07 | Sharp Corp | Driving circuit for optical semiconductor element |
| JPH10256610A (en) * | 1997-01-10 | 1998-09-25 | Rohm Co Ltd | Semiconductor light emitting device |
| JPH11307815A (en) * | 1998-04-23 | 1999-11-05 | Abikkusu Kk | Collective led lamp for ac power source |
| JP2006228904A (en) * | 2005-02-16 | 2006-08-31 | Sanken Electric Co Ltd | Compound semiconductor device |
| JP2007165161A (en) * | 2005-12-15 | 2007-06-28 | Sharp Corp | Led illumination device, led backlight device, and image display device |
| JP2007295758A (en) * | 2006-04-26 | 2007-11-08 | Denso Corp | Surge protector |
| JP2007324355A (en) * | 2006-05-31 | 2007-12-13 | Sony Corp | Light-emitting-diode lighting circuit, illuminating device, and liquid-crystal display device |
| JP2008130989A (en) * | 2006-11-24 | 2008-06-05 | Matsushita Electric Works Ltd | Led lighting circuit, and luminaire using the same |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8879010B2 (en) | 2010-01-24 | 2014-11-04 | Semiconductor Energy Laboratory Co., Ltd. | Display device |
| JP2012178559A (en) * | 2011-02-11 | 2012-09-13 | Tai-Her Yang | Led device |
| US9064452B2 (en) | 2012-03-19 | 2015-06-23 | Samsung Display Co., Ltd. | Organic light emitting diode display |
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