JPH05136461A - Led drive circuit for optical transmitter - Google Patents
Led drive circuit for optical transmitterInfo
- Publication number
- JPH05136461A JPH05136461A JP29896591A JP29896591A JPH05136461A JP H05136461 A JPH05136461 A JP H05136461A JP 29896591 A JP29896591 A JP 29896591A JP 29896591 A JP29896591 A JP 29896591A JP H05136461 A JPH05136461 A JP H05136461A
- Authority
- JP
- Japan
- Prior art keywords
- converter
- voltage
- leds
- power supply
- drive circuit
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、リモコン送信機や空間
伝送用光通信ユニット等の光送信器のＬＥＤ駆動回路に
関するもので、特に乾電池によって多数個のＬＥＤに大
電流を供給するときに使用されるものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LED drive circuit for an optical transmitter such as a remote control transmitter or an optical communication unit for space transmission, and is particularly used for supplying a large current to a large number of LEDs by dry batteries. Is done.
【０００２】[0002]
【従来の技術】従来のリモコン送信機や空間伝送用光通
信ユニットのＬＥＤ駆動回路は、図３に示すように、多
数個の乾電池１１を直列接続することによって高い直流
電圧を得、これを多数個の直列接続したＬＥＤ１２に印
加したり、図４に示すように、乾電池１１および駆動用
トランジスタ１３の許容範囲内で多数個のＬＥＤ１２を
並列接続したりして、個々のＬＥＤ１２に流れる電流を
大きく保ち、到達距離を伸ばしたり、指向性を広範囲に
していた。2. Description of the Related Art As shown in FIG. 3, a conventional LED drive circuit of a remote control transmitter or an optical communication unit for space transmission obtains a high DC voltage by connecting a large number of dry cells 11 in series, and outputs a high DC voltage. The current flowing to each LED 12 is increased by applying the voltage to each of the LEDs 12 connected in series or connecting a plurality of LEDs 12 in parallel within the allowable range of the dry battery 11 and the driving transistor 13 as shown in FIG. I kept it, extended the reach, and widened the directivity.
【０００３】なお図３，図４において、１４は駆動用ト
ランジスタ１３のベース電流制限抵抗、１５はＬＥＤ順
電流制限抵抗、１６は平滑用コンデンサである。In FIGS. 3 and 4, 14 is a base current limiting resistor of the driving transistor 13, 15 is an LED forward current limiting resistor, and 16 is a smoothing capacitor.
【０００４】[0004]
【発明が解決しようとする課題】従来のリモコン送信機
や空間伝送用光通信ユニットの駆動回路では、多数個の
ＬＥＤ１２を駆動する場合、図３に示すように、消費電
流を抑えるためＬＥＤ１２を直列接続して電源を供給す
るが、印加電圧を高くする必要があり、ＬＥＤ１２の数
に応じて乾電池１１の数も増やさなければならない。ま
た、図４に示すように、ＬＥＤ１２を並列接続すれば印
加電圧は高くする必要はないが、ＬＥＤ１２の数に応じ
て消費電流は大きくなる。さらに、駆動用トランジスタ
１３のコレクタ電流定格により、ＬＥＤ１２の数はむや
みに多くはできないという欠点もある。In the drive circuit of the conventional remote control transmitter or the optical communication unit for space transmission, when driving a large number of LEDs 12, as shown in FIG. 3, the LEDs 12 are connected in series in order to suppress current consumption. Although the power source is connected and power is supplied, the applied voltage needs to be increased and the number of dry cells 11 must be increased according to the number of LEDs 12. Further, as shown in FIG. 4, if the LEDs 12 are connected in parallel, it is not necessary to increase the applied voltage, but the current consumption increases according to the number of LEDs 12. Further, there is a drawback that the number of LEDs 12 cannot be unnecessarily increased due to the collector current rating of the driving transistor 13.
【０００５】本発明は、電源電圧は低いままかつ、消費
電流も小さいまま多数個のＬＥＤを駆動しようとするも
のである。The present invention is intended to drive a large number of LEDs while keeping the power supply voltage low and the current consumption low.
【０００６】[0006]
【課題を解決するための手段】本発明のＬＥＤ駆動回路
は、乾電池を電源とするＤＣ−ＤＣコンバータを備えて
おり、ＤＣーＤＣコンバータの一方極性の電圧出力端と
前記出力とは逆極性の電圧入力端との間に複数のＬＥＤ
を直列接続することを特徴とする。The LED drive circuit of the present invention is provided with a DC-DC converter using a dry battery as a power source, and the voltage output terminal of one polarity of the DC-DC converter and the output having the opposite polarity. Multiple LEDs between the voltage input terminal
Is connected in series.
【０００７】さらに、ＤＣ−ＤＣコンバータの電源供給
を制御するための電源コントロール回路を備えてもよ
い。Further, a power supply control circuit for controlling the power supply of the DC-DC converter may be provided.
【０００８】[0008]
【作用】ＤＣ−ＤＣコンバータは例えば負電圧出力のも
のであり、このＤＣーＤＣコンバータへの正電圧入力と
負電圧出力との間に複数個のＬＥＤを直列接続すること
により、ＬＥＤ列にはほぼ正電圧値と負電圧値の絶対値
の和の電圧が印加できる。またＤＣ−ＤＣコンバータ自
身も電流を消費するため、送信信号を出力するときの
み、直前にＤＣ−ＤＣコンバータへ電源供給するようコ
ントロールする。The DC-DC converter is, for example, of a negative voltage output. By connecting a plurality of LEDs in series between the positive voltage input and the negative voltage output of the DC-DC converter, the LED string is not connected. A voltage that is approximately the sum of the absolute values of the positive voltage value and the negative voltage value can be applied. Further, since the DC-DC converter itself consumes current, it is controlled to supply power to the DC-DC converter immediately before the transmission signal is output.
【０００９】[0009]
【実施例】本発明の実施例を図１に、また図１中の各点
のタイムチャートを図２に示す。本例では、リモコン送
信機や空間伝送用光通信ユニット等の駆動回路として負
電圧出力のＤＣ−ＤＣコンバータ１を用い、ＤＣ−ＤＣ
コンバータ１に入力する正電圧と負電圧出力の電位差に
より、多数個直列接続された赤外発光等のＬＥＤ１２を
駆動する。また、使用するＤＣ−ＤＣコンバータ１自身
の消費電流を抑えるため、電源コントロール回路２を付
加し、送信時のみＤＣ−ＤＣコンバータ１へ電源供給す
るようにしている。FIG. 1 shows an embodiment of the present invention, and FIG. 2 shows a time chart of each point in FIG. In this example, a negative voltage output DC-DC converter 1 is used as a drive circuit for a remote control transmitter, an optical communication unit for space transmission, etc.
A large number of LEDs 12 such as infrared rays connected in series are driven by the potential difference between the positive voltage input to the converter 1 and the negative voltage output. Further, in order to suppress the current consumption of the DC-DC converter 1 itself used, a power supply control circuit 2 is added so that power is supplied to the DC-DC converter 1 only during transmission.
【００１０】図２を参照してさらに具体的に説明する。A more specific description will be given with reference to FIG.
【００１１】リモコン送信機や空間伝送用光通信ユニッ
トにおいて、マイコンから送信信号ＳＩＧを出力する場
合、まずマイコンの別ポートから、電源コントロール信
号としてＣＯＮＴ＝“Ｈ”とする。ここで乾電池１１の
両端電圧ＶDDを＋６Ｖとし、これをレギュレートしてマ
イコンは＋５Ｖで動作しているとする。ＣＯＮＴ信号に
より電源コントロール回路２が制御され、ＤＣ−ＤＣコ
ンバータ１の入力端にＶI として＋６Ｖが印加される。
ＤＣ−ＤＣコンバータ１では直ちに出力端より負電圧−
ＶO を出力する。In the remote control transmitter or the optical communication unit for space transmission, when the transmission signal SIG is output from the microcomputer, CONT = “H” is set as a power supply control signal from another port of the microcomputer. Here, it is assumed that the voltage V DD across the dry battery 11 is set to + 6V, and this is regulated to operate the microcomputer at + 5V. The power supply control circuit 2 is controlled by the CONT signal, and + 6V is applied as V I to the input terminal of the DC-DC converter 1.
In the DC-DC converter 1, a negative voltage is immediately applied from the output end.
Output V O.
【００１２】ここで、一例として−ＶO を−１２Ｖとす
ると、ＬＥＤ１２の駆動用トランジスタ１３のエミッタ
と、ＤＣ−ＤＣコンバータ１の入力電圧ＶI との間の電
位差は１７Ｖとなるから、この間に赤外ＬＥＤ（順電圧
約２Ｖ）１２を８個直列接続して同一の電流で駆動でき
る。ＬＥＤ１２に流れる電流は直列に入れた電流制限抵
抗１５の値によって決まる。[0012] Here, when -12V to -V O as an example, and the emitter of the driving transistor 13 of the LED 12, the potential difference between the input voltage V I of the DC-DC converter 1 from the 17 V, during which Eight infrared LEDs (forward voltage of about 2 V) 12 can be connected in series and driven by the same current. The current flowing through the LED 12 is determined by the value of the current limiting resistor 15 placed in series.
【００１３】次に、このような高電圧を印加した状態で
マイコンから送信信号ＳＩＧを出力し、駆動用トランジ
スタ１３をＯＮ−ＯＦＦする。ＳＩＧ＝“Ｌ”のとき駆
動用トランジスタ１３がＯＦＦするよう、ベースにはＤ
Ｃ−ＤＣコンバータ１の負出力電圧ＶO にほぼ等しいツ
エナー電圧ＶZ をもつツエナーダイオード３を挿入して
いる。Next, the transmission signal SIG is output from the microcomputer while the high voltage is applied, and the driving transistor 13 is turned on and off. The base has D so that the driving transistor 13 is turned off when SIG = “L”.
A Zener diode 3 having a Zener voltage V Z substantially equal to the negative output voltage V O of the C-DC converter 1 is inserted.
【００１４】ＳＩＧ＝“Ｈ”のとき、駆動用トランジス
タ１３のコレクタは電圧ＶL≒１７Ｖで振幅するから、
先述のように、８個の赤外ＬＥＤ１２に抵抗１５で決め
られた同一の電流を流すことができる。マイコンは送信
終了と共にＣＯＮＴ＝“Ｌ”としてＤＣ−ＤＣコンバー
タ１への電源供給を停止し、無駄なＤＣ−ＤＣコンバー
タ１自身での電流消費を抑える。When SIG = “H”, the collector of the driving transistor 13 swings at a voltage V L ≈17 V,
As described above, the same current determined by the resistor 15 can be passed through the eight infrared LEDs 12. Upon completion of the transmission, the microcomputer sets CONT = “L” to stop the power supply to the DC-DC converter 1 and suppress wasteful consumption of current in the DC-DC converter 1 itself.
【００１５】[0015]
【発明の効果】以上のように本発明は、希望する到達距
離・指向性に必要な数のＬＥＤを直列接続して、同一の
電流で駆動できるだけの一極性出力のＤＣ−ＤＣコンバ
ータを備えてなり、一極性出力電圧と逆極性入力電圧の
電位差により、多数個のＬＥＤを通常のリモコン送信機
並の電源電圧供給，消費電流で駆動することができ、乾
電池の本数削減と寿命延長によりコストダウンが期待で
きる。As described above, the present invention comprises a DC-DC converter having a unipolar output capable of driving at the same current by connecting as many LEDs as necessary for a desired reach and directivity. Therefore, due to the potential difference between the one-polarity output voltage and the opposite-polarity input voltage, it is possible to drive a large number of LEDs with the same power supply voltage and current consumption as an ordinary remote control transmitter, reducing costs by reducing the number of dry cells and extending their life. Can be expected.
【図面の簡単な説明】[Brief description of drawings]
【図１】本発明の一実施例を示す回路図である。FIG. 1 is a circuit diagram showing an embodiment of the present invention.
【図２】図１の各部信号波形を示すタイムチャートであ
る。FIG. 2 is a time chart showing signal waveforms of respective parts of FIG.
【図３】従来例を示す回路図である。FIG. 3 is a circuit diagram showing a conventional example.
【図４】他の従来例を示す回路図である。FIG. 4 is a circuit diagram showing another conventional example.
１ ＤＣ−ＤＣコンバータ ２ 電源コントロール回路 １１ 乾電池 １２ ＬＥＤ １３ 駆動用トランジスタ ＶI ＤＣ−ＤＣコンバータへの入力電圧 ＶO ＤＣ−ＤＣコンバータへの出力電圧1 DC-DC converter 2 power control circuit 11 battery 12 LED 13 input voltage V O DC-DC output voltage to the converter to the driving transistor V I DC-DC converter
Claims (2)
タを備えてなり、前記ＤＣ−ＤＣコンバータの一方極性
の電圧出力端と前記出力とは逆極性の電圧入力端との間
に複数の光送信用ＬＥＤを直列接続したことを特徴とす
る光送信器のＬＥＤ駆動回路。1. A DC-DC converter using a dry battery as a power source, wherein a plurality of optical transmitters are provided between a voltage output terminal having one polarity of the DC-DC converter and a voltage input terminal having a polarity opposite to the output. An LED drive circuit for an optical transmitter, in which credit LEDs are connected in series.
制御する電源コントロール回路を備えたことを特徴とす
る請求項１に記載の光送信器のＬＥＤ駆動回路。2. The LED drive circuit for an optical transmitter according to claim 1, further comprising a power supply control circuit for controlling power supply of the DC-DC converter.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29896591A JPH05136461A (en) | 1991-11-14 | 1991-11-14 | Led drive circuit for optical transmitter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29896591A JPH05136461A (en) | 1991-11-14 | 1991-11-14 | Led drive circuit for optical transmitter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH05136461A true JPH05136461A (en) | 1993-06-01 |
Family
ID=17866480
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP29896591A Pending JPH05136461A (en) | 1991-11-14 | 1991-11-14 | Led drive circuit for optical transmitter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH05136461A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1286567A3 (en) * | 2001-07-31 | 2005-05-25 | Hella KGaA Hueck & Co. | Lighting device |
| JP2005136157A (en) * | 2003-10-30 | 2005-05-26 | Rohm Co Ltd | Light emitting element driving device, display module having same driving device, and electronic device having same module |
| JP2009517856A (en) * | 2005-11-25 | 2009-04-30 | オスラム ゲゼルシャフト ミット ベシュレンクテル ハフツング | Circuit device with high-side back transistor |
| WO2012098486A1 (en) | 2011-01-17 | 2012-07-26 | Koninklijke Philips Electronics N.V. | Driver device and driving method for driving a load, in particular an led unit |
| US8300041B2 (en) | 2006-07-14 | 2012-10-30 | Chimei Innolux Corporation | LCD display and backlight apparatus and driving method thereof |
-
1991
- 1991-11-14 JP JP29896591A patent/JPH05136461A/en active Pending
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1286567A3 (en) * | 2001-07-31 | 2005-05-25 | Hella KGaA Hueck & Co. | Lighting device |
| JP2005136157A (en) * | 2003-10-30 | 2005-05-26 | Rohm Co Ltd | Light emitting element driving device, display module having same driving device, and electronic device having same module |
| JP2009517856A (en) * | 2005-11-25 | 2009-04-30 | オスラム ゲゼルシャフト ミット ベシュレンクテル ハフツング | Circuit device with high-side back transistor |
| US8300041B2 (en) | 2006-07-14 | 2012-10-30 | Chimei Innolux Corporation | LCD display and backlight apparatus and driving method thereof |
| WO2012098486A1 (en) | 2011-01-17 | 2012-07-26 | Koninklijke Philips Electronics N.V. | Driver device and driving method for driving a load, in particular an led unit |
| US9271348B2 (en) | 2011-01-17 | 2016-02-23 | Koninklijke Philips N.V. | Driver device and driving method for driving a load, in particular an LED unit |
| US9596726B2 (en) | 2011-01-17 | 2017-03-14 | Philips Lighting Holding B.V. | Driver device and driving method for driving a load, in particular an LED unit |
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