JPS58137340A - Light emitting diode driving circuit - Google Patents

Light emitting diode driving circuit

Info

Publication number
JPS58137340A
JPS58137340A JP57019369A JP1936982A JPS58137340A JP S58137340 A JPS58137340 A JP S58137340A JP 57019369 A JP57019369 A JP 57019369A JP 1936982 A JP1936982 A JP 1936982A JP S58137340 A JPS58137340 A JP S58137340A
Authority
JP
Japan
Prior art keywords
emitting diode
light emitting
waveform
rectangular wave
current
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
Application number
JP57019369A
Other languages
Japanese (ja)
Inventor
Atsushi Iwaoka
岩岡 篤
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Panasonic Holdings Corp
Original Assignee
Matsushita Electric Industrial Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Matsushita Electric Industrial Co Ltd filed Critical Matsushita Electric Industrial Co Ltd
Priority to JP57019369A priority Critical patent/JPS58137340A/en
Publication of JPS58137340A publication Critical patent/JPS58137340A/en
Pending legal-status Critical Current

Links

Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B10/00Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/50Transmitters
    • H04B10/501Structural aspects
    • H04B10/502LED transmitters

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Led Devices (AREA)
  • Dc Digital Transmission (AREA)
  • Optical Communication System (AREA)

Abstract

PURPOSE:To drive a light emitting diode at a high speed by a single power source through a simple circuit, by using the incomplete differential wave of an input rectangular wave signal as a peaking current. CONSTITUTION:The rectangular wave (a) for driving the light emitting diode is applied through an input terminal 17 to a switch means 23 to allow a current with the same waveform with the rectangular wave (a) to flow from a positive power source terminal to the light emitting diode 22. An incomplete differentiator 8, on the other hand, differentiates the rectangular wave (a) to generate signal with a waveform (b), which is applied to an adder 19. Then, the adder 19 flows the current with a waveform (c) obtained by adding the rectangular wave (a) and waveform (b) together to the light emitting diode 22, which is driven at a high speed by a peaking current with an output waveform (b) from the incomplete differentiator.

Description

【発明の詳細な説明】 本発明は、発光ダイオードを発光素子に用いた光デジタ
ルデータ送信回路等に用いる発光ダイオード駆動回路に
関し、発光ダイオード出力光波形の立ち上り時間、及び
立ち下り時間を短縮することによって高速データ伝送を
行うことを目的とするものである。
DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a light emitting diode drive circuit used in an optical digital data transmission circuit using a light emitting diode as a light emitting element, and to shorten the rise time and fall time of a light waveform output from a light emitting diode. The purpose is to perform high-speed data transmission by using

第1図は従来の発光ダイオード駆動回路の回路図を示し
ている。第1図において、1は信号入力端、2〜4はタ
イミング回路、6は参照電圧源接続端、6〜9はトラン
ジスタ、10は発光ダイオード、11は発光ダイオード
を逆バイアス電圧から保護するだめのダイオード、12
.13は抵抗、14は定電流源、15は正電源端、16
は負電源端を示す。
FIG. 1 shows a circuit diagram of a conventional light emitting diode driving circuit. In Figure 1, 1 is a signal input terminal, 2 to 4 are timing circuits, 6 is a reference voltage source connection terminal, 6 to 9 are transistors, 10 is a light emitting diode, and 11 is a terminal for protecting the light emitting diode from reverse bias voltage. Diode, 12
.. 13 is a resistor, 14 is a constant current source, 15 is a positive power supply terminal, 16
indicates the negative power supply terminal.

第2図a −hはそれぞれ第1図に示す従来の発光ダイ
オード駆動回路のa−に4の各部の波形を示している。
FIGS. 2a to 2h show waveforms at respective portions a to 4 of the conventional light emitting diode drive circuit shown in FIG. 1, respectively.

第1図及び第2図ともに、a −cは各都電圧波形、d
−9は各部電流波形、hは出力光波形を示す。
In both Figures 1 and 2, a - c are voltage waveforms in each city, d
-9 indicates the current waveform of each part, and h indicates the output light waveform.

次に上記従来例の動作について説明する。発光ダイオー
ド1oを高速駆動する際に第2図dに示す電流波形で駆
動したのでは発光ダイオード10の接合容量及び拡散容
量のために光出力波形はなまってしまう。そこで同図e
、fのピーキングパルスを加えた電流波形qで駆動する
ことによって発光ダイオード10の接合容量及び拡散容
量の充放電時間を短縮することができ、出方光波形の立
ち上り時間及び立ち下り時間も短縮できる。第1図にお
いて信号入力端1に加えられた矩形波信号から、タイミ
ング回路2〜4によってパルス波形a ”−Cヲつくり
、これらでトランジスタ6〜18を駆動して発光ダイオ
ード駆動電流qを合成している。
Next, the operation of the above conventional example will be explained. If the light emitting diode 1o is driven at high speed with the current waveform shown in FIG. Therefore, the same figure e
By driving with the current waveform q to which peaking pulses of , f are added, the charging/discharging time of the junction capacitance and the diffusion capacitance of the light emitting diode 10 can be shortened, and the rise time and fall time of the output light waveform can also be shortened. . In FIG. 1, from the rectangular wave signal applied to the signal input terminal 1, the timing circuits 2 to 4 create a pulse waveform a''-C, which drives the transistors 6 to 18 to synthesize the light emitting diode drive current q. ing.

しかしながら上記従来例においては、正負の2電源が必
要であり、ピーキングパルスをつくるたののタイミング
回路2〜4を必要とするなど、簡易な光送信回路には適
用しにくいという欠点があった。
However, the above-mentioned conventional example requires two power sources, positive and negative, and requires timing circuits 2 to 4 for generating peaking pulses, which makes it difficult to apply to a simple optical transmission circuit.

本発明は上記従来の欠点を除去するものであり以下に本
発明の基本構成について第3図とともに説明する。
The present invention eliminates the above-mentioned conventional drawbacks, and the basic configuration of the present invention will be explained below with reference to FIG. 3.

第3図において、a % Cは各都電圧波形及び電流波
形、dは出力光波形を示す。また、17は信号電圧入力
端、18は不完全微分器、19は加算器、20.21は
抵抗、22は発光ダイオード、23はスイッチ手段、2
4は正電源端、25は接地端を示している。
In FIG. 3, a % C indicates each voltage waveform and current waveform, and d indicates an output light waveform. Further, 17 is a signal voltage input terminal, 18 is an incomplete differentiator, 19 is an adder, 20.21 is a resistor, 22 is a light emitting diode, 23 is a switch means, 2
4 indicates a positive power supply terminal, and 25 indicates a ground terminal.

次に第3図に示す回路の動作について第4図a〜dとと
もに説明する。第3図において信号入力端17に加えら
れた矩形波電圧信号aは信号がf(ighのときにはス
イッチ手段23を閉じ、Lowのときには開き、波形a
と同じ波形の電流を発光ダイオード22に流すように動
作する。一方、入力信号波形aは不完全微分器18によ
って波形すに変換され、加算器19によって発光ダイオ
ード駆動電流波形Cが合成される。なお、抵抗2oは発
光ダイオード22の負荷抵抗、抵抗21は入力信号の立
ち下がり時に発光ダイオード22を逆方向バイアスする
ためのバイアス抵抗である。
Next, the operation of the circuit shown in FIG. 3 will be explained with reference to FIGS. 4a to 4d. In FIG. 3, the rectangular voltage signal a applied to the signal input terminal 17 closes the switch means 23 when the signal f (high), opens it when it is low, and the waveform a
The light-emitting diode 22 operates to cause a current having the same waveform as that to flow through the light-emitting diode 22. On the other hand, the input signal waveform a is converted into a waveform S by an incomplete differentiator 18, and a light emitting diode drive current waveform C is synthesized by an adder 19. Note that the resistor 2o is a load resistance of the light emitting diode 22, and the resistor 21 is a bias resistor for biasing the light emitting diode 22 in the reverse direction when the input signal falls.

本発明の駆動回路は単に不完全微分器18のみでピーキ
ングパルスをつくることができるので従来例のような複
雑なタイミング回路を必要とせず単一電源で動作すると
いう利点を有する。
Since the drive circuit of the present invention can generate peaking pulses simply by using the imperfect differentiator 18, it has the advantage of not requiring a complicated timing circuit like the conventional example and operating with a single power supply.

第6図は本発明の実施例を示j〜た回路図である。FIG. 6 is a circuit diagram showing an embodiment of the present invention.

第5図において、26は信号電圧入力端、29は電源端
、28はインバータ、29.30はトランジスタ、31
〜33は抵抗、34はコンデンサ、35は発光ダイオー
ドを逆バイアス電圧から保護するためのダイオード、3
6は発光ダイオードを示す。
In FIG. 5, 26 is a signal voltage input terminal, 29 is a power supply terminal, 28 is an inverter, 29.30 is a transistor, and 31
~33 is a resistor, 34 is a capacitor, 35 is a diode for protecting the light emitting diode from reverse bias voltage, 3
6 indicates a light emitting diode.

次に上記実施例の動作について第5図とともに説明する
。第6図において、信号電圧入力端26に加えられた矩
形波信号はトランジスタ29によって電流信号に変換さ
れる。一方、インバータ28を通って位相が反転した信
号波形はトランジスタ30のコレクタ側に現われる。い
ま、入力信号が立ち上るとトランジスタ29によって発
光ダイオード36に順方向電流が流れるが、同時にトラ
ンジスタ3oはオフし、発光ダイオード36のアノード
にはコンデンサ34及び抵抗31などで決まる時定数を
もったピーキング電流が加えられる。
Next, the operation of the above embodiment will be explained with reference to FIG. In FIG. 6, a rectangular wave signal applied to signal voltage input terminal 26 is converted into a current signal by transistor 29. In FIG. On the other hand, a signal waveform whose phase has been inverted after passing through the inverter 28 appears on the collector side of the transistor 30. Now, when the input signal rises, a forward current flows through the light emitting diode 36 by the transistor 29, but at the same time, the transistor 3o turns off, and a peaking current with a time constant determined by the capacitor 34, the resistor 31, etc. is applied to the anode of the light emitting diode 36. is added.

また、入力信号が立ち下がると、トランジスタ29はオ
フし、抵抗33によって発光ダイオード36のカンード
は電源電圧となるが、同時にトランジスタ30はオンす
るので、コンデンサ34及びトランジスタ30などで決
まる時定数をもったピーキング電流により発光ダイオー
ド36を逆方向バイアスすることができる。
Furthermore, when the input signal falls, the transistor 29 is turned off and the cand of the light emitting diode 36 becomes the power supply voltage due to the resistor 33, but at the same time, the transistor 30 is turned on, so a time constant determined by the capacitor 34, the transistor 30, etc. The peaking current can reverse bias the light emitting diode 36.

以上の動作によって発光ダイオードゝ36を第4図Cに
示した電流波形で駆動することができる。
By the above operation, the light emitting diode 36 can be driven with the current waveform shown in FIG. 4C.

本実施例は、抵抗及びコンデンサのみによって微分時定
数、ピーキング電流値を設定でき、単一電源で動作する
ので、簡易な光デジタルデータ伝送回路などに適用でき
るという利点を有する。
This embodiment has the advantage that the differential time constant and peaking current value can be set using only a resistor and a capacitor, and it operates with a single power supply, so that it can be applied to a simple optical digital data transmission circuit.

本発明は上記のような構成であり、本発明によれば、単
に入力矩形波信号の不完全微分波形をピーキング電流と
して用いるので複雑なタイミング回路などは不要であり
、簡易な回路で、しかも単一電源で、発光ダイオードの
高速駆動が可能となる利点を有する。
The present invention has the above-described configuration, and according to the present invention, since the imperfectly differentiated waveform of the input rectangular wave signal is simply used as the peaking current, a complicated timing circuit is not necessary, and the circuit is simple. This has the advantage that the light emitting diode can be driven at high speed with a single power source.

【図面の簡単な説明】[Brief explanation of the drawing]

第1図は従来の発光ダイオード駆動回路の回路図、第2
図a −hは従来の発光ダイオニド駆動回路の各部の波
形を示す図、第3図は本発明の発光ダイオード駆動回路
の基本構成を示す図、第4図a −dは第3図の各部の
波形を示す図、第5図は本発明の一実施例における発光
ダイオード駆動回路の回路図である。 17・・・・・・信号電圧入力端、18・・・・・・不
完全微分器、19・・・・・・加算器、20.21・・
・・・・抵抗、22・・・・・・発光ダイオード、23
・・・・・・スイッチ手段、24・・・・・・正電源端
、26・・・・・・接地端、26・・・・・・信号電圧
入力端、27・・・・・・電源端、28@・・■・イン
バータ、29.30−・・・・・トランジスタ、31〜
33・・・・・0抵抗、34・・・・・・コンデンサ、
35・・・・・・ダイオード、36・・・・・・発光ダ
イオード。 代理人の氏名 弁理士 中 尾 敏 男 ほか1名第1
図 V 12図
Figure 1 is a circuit diagram of a conventional light emitting diode drive circuit;
Figures a to h are diagrams showing the waveforms of each part of a conventional light emitting diode drive circuit, Figure 3 is a diagram showing the basic configuration of the light emitting diode drive circuit of the present invention, and Figures 4a to d are diagrams showing the waveforms of each part of the conventional light emitting diode drive circuit. FIG. 5, a diagram showing waveforms, is a circuit diagram of a light emitting diode drive circuit in an embodiment of the present invention. 17...Signal voltage input terminal, 18...Incomplete differentiator, 19...Adder, 20.21...
...Resistor, 22...Light-emitting diode, 23
...Switch means, 24...Positive power supply terminal, 26...Ground terminal, 26...Signal voltage input terminal, 27...Power supply End, 28@...■ Inverter, 29.30-...Transistor, 31~
33...0 resistance, 34...capacitor,
35...Diode, 36...Light emitting diode. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure V 12

Claims (1)

【特許請求の範囲】[Claims] 入力矩形波信号によって制御されるスイッチ手段と、こ
のスイッチ手段によって制御される発光ダイオードと、
上記入力矩形波信号を不完全微分する不完全微分手段と
、上記スイッチ手段の導通時に上記発光ダイオードに流
れる電流に上記不完全微分手段の出力を加算する手段と
、上記入力矩形波信号の立ち下がり時に上記発光ダイオ
ードを逆バイアスする逆バイアス手段とを具備してなる
発光ダイオード駆動回路。
a switch means controlled by an input square wave signal; a light emitting diode controlled by the switch means;
imperfect differentiating means for imperfectly differentiating the input rectangular wave signal; means for adding the output of the imperfect differentiating means to the current flowing through the light emitting diode when the switch means is conductive; and a falling edge of the input rectangular wave signal. and reverse bias means for reverse biasing the light emitting diode.
JP57019369A 1982-02-09 1982-02-09 Light emitting diode driving circuit Pending JPS58137340A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP57019369A JPS58137340A (en) 1982-02-09 1982-02-09 Light emitting diode driving circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP57019369A JPS58137340A (en) 1982-02-09 1982-02-09 Light emitting diode driving circuit

Publications (1)

Publication Number Publication Date
JPS58137340A true JPS58137340A (en) 1983-08-15

Family

ID=11997424

Family Applications (1)

Application Number Title Priority Date Filing Date
JP57019369A Pending JPS58137340A (en) 1982-02-09 1982-02-09 Light emitting diode driving circuit

Country Status (1)

Country Link
JP (1) JPS58137340A (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6014535A (en) * 1983-07-05 1985-01-25 Nec Corp Optical transmitting circuit
JPS60108057U (en) * 1983-12-26 1985-07-23 ミツミ電機株式会社 optical transmitter
JPH0327580A (en) * 1989-06-24 1991-02-05 Sony Corp Light emitting diode drive circuit
JPH0327579A (en) * 1989-06-24 1991-02-05 Mitsubishi Rayon Co Ltd Light emitting diode drive circuit
US5140175A (en) * 1989-06-24 1992-08-18 Mitsubishi Rayon Co., Ltd. Light-emitting diode drive circuit with fast rise time and fall time

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS51147983A (en) * 1975-06-14 1976-12-18 Fujitsu Ltd Driving circuit for light emission diode
JPS5739593A (en) * 1980-08-22 1982-03-04 Nec Corp Driving circuit of semiconductor light emitting element

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS51147983A (en) * 1975-06-14 1976-12-18 Fujitsu Ltd Driving circuit for light emission diode
JPS5739593A (en) * 1980-08-22 1982-03-04 Nec Corp Driving circuit of semiconductor light emitting element

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6014535A (en) * 1983-07-05 1985-01-25 Nec Corp Optical transmitting circuit
JPH0224420B2 (en) * 1983-07-05 1990-05-29 Nippon Electric Co
JPS60108057U (en) * 1983-12-26 1985-07-23 ミツミ電機株式会社 optical transmitter
JPH0327580A (en) * 1989-06-24 1991-02-05 Sony Corp Light emitting diode drive circuit
JPH0327579A (en) * 1989-06-24 1991-02-05 Mitsubishi Rayon Co Ltd Light emitting diode drive circuit
US5140175A (en) * 1989-06-24 1992-08-18 Mitsubishi Rayon Co., Ltd. Light-emitting diode drive circuit with fast rise time and fall time

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