JPS58196734A - Photoelectric converting circuit - Google Patents

Photoelectric converting circuit

Info

Publication number
JPS58196734A
JPS58196734A JP57079360A JP7936082A JPS58196734A JP S58196734 A JPS58196734 A JP S58196734A JP 57079360 A JP57079360 A JP 57079360A JP 7936082 A JP7936082 A JP 7936082A JP S58196734 A JPS58196734 A JP S58196734A
Authority
JP
Japan
Prior art keywords
voltage
photodetecting element
source
conversion circuit
photoelectric conversion
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.)
Granted
Application number
JP57079360A
Other languages
Japanese (ja)
Other versions
JPH0145783B2 (en
Inventor
Akira Fukuda
晃 福田
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.)
Sumitomo Electric Industries Ltd
Original Assignee
Sumitomo Electric Industries 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 Sumitomo Electric Industries Ltd filed Critical Sumitomo Electric Industries Ltd
Priority to JP57079360A priority Critical patent/JPS58196734A/en
Publication of JPS58196734A publication Critical patent/JPS58196734A/en
Publication of JPH0145783B2 publication Critical patent/JPH0145783B2/ja
Granted legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/60—Receivers
    • H04B10/66—Non-coherent receivers, e.g. using direct detection
    • H04B10/69—Electrical arrangements in the receiver
    • H04B10/691—Arrangements for optimizing the photodetector in the receiver
    • H04B10/6911—Photodiode bias control, e.g. for compensating temperature variations

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Optical Communication System (AREA)

Abstract

PURPOSE:To obtain the amplitude of an output signal which is nearly equal to that of a power supply voltage, by using a depletion type FET, and canceling the parasitic capacity of a photodetecting element and widening a received signal band. CONSTITUTION:This photoelectric converting circuit is constituted by connecting the photodetecting element 1 between the source and gate of the depletion type FET3 which operates as a source follower amplifier. The source follower amplifier has extremely large impedance and a resistance R3 is set sufficiently large. When there is no light signal, the gate voltage VG of the FET3 is zero and the source voltage is a reverse voltage necessary for a circuit including the photodetecting element 1. When a light signal arrives, a photodetection current generated by the photodetecting element 1 flows through the resistance R3 and the voltage VG varies. Consequently, the voltage across an output reresistance R4 also varies following up the voltage VG. In this case, the reverse bias voltage of the photodetecting element 1 is still constant and this circuit operates without the influence of the parasitic capacity of the element 1.

Description

【発明の詳細な説明】 本発明は九通信システムにおいて光信号を電気信号に変
換する光電変換回路に関し、詳細には受信信号帯域が受
光素子の寄生容量によって制限を受けずかつ電源電圧の
大きさにはソ等しい出力振幅を有する電気信号が得られ
る光電変換回路に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a photoelectric conversion circuit that converts an optical signal into an electrical signal in a nine-way communication system, and more particularly, the present invention relates to a photoelectric conversion circuit that converts an optical signal into an electrical signal in a communication system, and more particularly, the present invention relates to a photoelectric conversion circuit that converts an optical signal into an electrical signal in a communication system. The present invention relates to a photoelectric conversion circuit that can obtain electrical signals having equal output amplitudes.

第１図はｆｌ’ｆ：末の光電変換回路を例示する図であ
る。この光電変換回路は光信号を受光素子であるフォト
ダイオード１を流れる電流に変換し５、このフォトダイ
オード１の電流を直列に設けた負曲り（抗Ｒ１に流しこ
の負荷抵抗ｔｔ　１の両端に発生した電圧を電気信号出
力として取り出すものである。FIG. 1 is a diagram illustrating a photoelectric conversion circuit at the end of fl'f. This photoelectric conversion circuit converts an optical signal into a current flowing through a photodiode 1, which is a light receiving element. This voltage is extracted as an electrical signal output.

この方式の光電変換回路はフォトダイオード１の寄生容
量と、直列に設けられた負荷抵抗１（１による回路時定
数により受信信号帯域が制限されるという欠点がある。This type of photoelectric conversion circuit has the drawback that the received signal band is limited by the parasitic capacitance of the photodiode 1 and the circuit time constant due to the load resistor 1 (1) provided in series.

第２図は従来の別の光電変換回路を例示する図である。FIG. 2 is a diagram illustrating another conventional photoelectric conversion circuit.

この光電変換回路はフォトダイオード１に変換器である
。逆相増幅器２は帯域が十分広く増幅１Ｗの大きいもの
が用いられているので、この方式の九′亀変換回路は受
信信号帯域が広い１．シかし７、この光電変換回路は十
分な受信信号帯域と利得とを持った逆相増幅器２が必要
であり、これを安定に動作させることは困難である。This photoelectric conversion circuit is a converter for the photodiode 1. Since the anti-phase amplifier 2 has a sufficiently wide band and a large amplification capacity of 1 W, this type of nine-tortoise conversion circuit has a wide receiving signal band. However, this photoelectric conversion circuit requires an anti-phase amplifier 2 having a sufficient reception signal band and gain, and it is difficult to operate it stably.

本発明の目的は、デプレッション形Ｆ１．，４１　ヲ用
いてバイアスを簡素化し、受光素子の寄生容量を打ち消
して受信信号帯域を広帯域化し、しかもはソ電源電圧に
等しい出力信号振幅が得られる光電変換回路を提供する
ことである。The object of the present invention is to provide a depression type F1. , 41 to simplify the bias, cancel out the parasitic capacitance of the light receiving element, widen the received signal band, and provide a photoelectric conversion circuit which can obtain an output signal amplitude equal to the power supply voltage.

↓゛Ｊ、下に図面を参照して本発明について詳細に説明
する。↓゛J, The present invention will be described in detail below with reference to the drawings.

第ろ図は本発明の光電変換回路の実施例を示す図である
。この光電変換回路はデプレッション形１・”　Ｉ＞　
Ｔ。・）ソースホロワ−増幅器であり、受光素子１はソ
ース・ゲート間に接続されている。この回路は電圧増幅
率が１であり、その入力インピーダンスが非常に高いの
でフォトダイオード等の受光素子１の負荷抵抗となる抵
抗Ｒろが十分大きく設定できる。ＦＴ＝；Ｔ　３はデプ
レッション形ＰＥＴでありバイアス電圧は負の電圧であ
って、受光素子１にはＩ”１＞Ｔ”３の逆バイアス電圧
がそのままか＼る。FIG. 5 is a diagram showing an embodiment of the photoelectric conversion circuit of the present invention. This photoelectric conversion circuit is a depression type 1.
T.・) It is a source follower amplifier, and the light receiving element 1 is connected between the source and gate. Since this circuit has a voltage amplification factor of 1 and an extremely high input impedance, the resistance R serving as the load resistance of the light receiving element 1 such as a photodiode can be set sufficiently large. FT=;T3 is a depletion type PET and the bias voltage is a negative voltage, and the reverse bias voltage of I"1>T"3 is applied to the light receiving element 1 as it is.

光信号がない場合には、負荷抵抗Ｒ６に流れる電流は受
光素子１の暗電流とＦＦ、Ｔろのゲート漏れ電流とであ
る。従って、ＦＥＴ３のゲート電圧ＶＧはほとんどＯＶ
となり、ＦＥＴろのソース電圧はこの回路に必要な逆バ
イアス電圧となる。この逆バイアス電圧が受光素子１の
逆バイアス電圧とｔｃる４、光信号が入力された場合に
は、受光素子１に生じる受光電流が負荷抵抗）Ｌ３に流
れてゲート電圧■；が変動する。この回路は電圧増幅率
が１であるから、出力端であるバイアス抵抗Ｒ４の電圧
もゲート電圧ＷＧに追従して変動する。つまり、受光素
子１の逆バイアス電圧は一定のま＼出力信号電圧が取り
出せることになり、受光素子１の寄生各州に対する充放
電は行なわれない。そのため信号帯域は受光素子１の負
荷抵抗Ｒろとその漂遊容址によって決まる時定数で制限
されるだけであり、光電変換回路の広帯域化が実現でき
る。また、出力電圧の振幅は電源電圧から光信号がない
場合の逆バイアス電圧とＦＥＴろのソース・ドレイン間
の飽和電圧とを差し引いた電圧となり、はゾ電源電圧と
同じ振幅が得られ電源電圧を有効に利用できる。When there is no optical signal, the current flowing through the load resistor R6 is the dark current of the light receiving element 1 and the gate leakage current of the FF and T filter. Therefore, the gate voltage VG of FET3 is almost OV
Therefore, the source voltage of the FET becomes the reverse bias voltage necessary for this circuit. This reverse bias voltage is the reverse bias voltage of the light-receiving element 1. When an optical signal is input, the light-receiving current generated in the light-receiving element 1 flows through the load resistor L3, and the gate voltage (2) changes. Since this circuit has a voltage amplification factor of 1, the voltage of the bias resistor R4, which is the output end, also fluctuates following the gate voltage WG. In other words, the output signal voltage can be obtained while the reverse bias voltage of the light receiving element 1 remains constant, and the parasitic states of the light receiving element 1 are not charged or discharged. Therefore, the signal band is limited only by the time constant determined by the load resistance R of the light receiving element 1 and its stray capacity, and a wide band of the photoelectric conversion circuit can be realized. Also, the amplitude of the output voltage is the voltage obtained by subtracting the reverse bias voltage when there is no optical signal and the saturation voltage between the source and drain of the FET from the power supply voltage, and the same amplitude as the power supply voltage can be obtained. Can be used effectively.

更に、この回路はＦＥＴ３をゲート入力を２つもつもの
に替えることにより出力バイアスの設定が容　　　　１
易にできる。Furthermore, this circuit allows you to set the output bias by replacing FET3 with one that has two gate inputs.
It's easy to do.

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

第１図及び第２図はそれぞれ従来の光電変換回路を例示
する図、第３図は本発明の光電変換回路の実施例を示す
図である。 １：受光素子　　　　　　　２：逆相増幅器３−電界効
宋トランジスタ　Ｒ１，Ｒ２，［５：負荷抵抗　ＩＬ４
：バイアス抵抗 特許出願人　住友電気工業株式会・社 第１図 第２図 第３図1 and 2 are diagrams each illustrating a conventional photoelectric conversion circuit, and FIG. 3 is a diagram illustrating an embodiment of the photoelectric conversion circuit of the present invention. 1: Photodetector 2: Negative phase amplifier 3 - field effect transistor R1, R2, [5: Load resistance IL4
: Bias resistor patent applicant: Sumitomo Electric Industries, Ltd. Figure 1 Figure 2 Figure 3

Claims (2)

【特許請求の範囲】[Claims] （１）デプレッション形電界効果トランジスタによるソ
ースホロワ−増幅器のソース−ゲート端子間に該トラン
ジスタのソース電圧が逆バイアス電圧となる向きに受光
素子を接続して成ることを特徴とする光電変換回路。(1) A photoelectric conversion circuit characterized in that a light receiving element is connected between the source and gate terminals of a source follower amplifier using a depletion type field effect transistor in such a direction that the source voltage of the transistor becomes a reverse bias voltage. （２）　　（１）において、前記受光素子がフォトダイ
オードからなることを特徴とする光電変換回路。(2) The photoelectric conversion circuit according to (1), characterized in that the light receiving element is composed of a photodiode.
JP57079360A 1982-05-12 1982-05-12 Photoelectric converting circuit Granted JPS58196734A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP57079360A JPS58196734A (en) 1982-05-12 1982-05-12 Photoelectric converting circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP57079360A JPS58196734A (en) 1982-05-12 1982-05-12 Photoelectric converting circuit

Publications (2)

Publication Number Publication Date
JPS58196734A true JPS58196734A (en) 1983-11-16
JPH0145783B2 JPH0145783B2 (en) 1989-10-04

Family

ID=13687723

Family Applications (1)

Application Number Title Priority Date Filing Date
JP57079360A Granted JPS58196734A (en) 1982-05-12 1982-05-12 Photoelectric converting circuit

Country Status (1)

Country Link
JP (1) JPS58196734A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS593650U (en) * 1982-06-30 1984-01-11 ソニー株式会社 Light receiving device
US4958500A (en) * 1989-04-20 1990-09-25 Hitachi, Ltd. Air conditioner and air conditioning method

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4921049A (en) * 1972-04-17 1974-02-25

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4921049A (en) * 1972-04-17 1974-02-25

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS593650U (en) * 1982-06-30 1984-01-11 ソニー株式会社 Light receiving device
US4958500A (en) * 1989-04-20 1990-09-25 Hitachi, Ltd. Air conditioner and air conditioning method

Also Published As

Publication number Publication date
JPH0145783B2 (en) 1989-10-04

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