JPH09172330A - Optical receiver - Google Patents
Optical receiverInfo
- Publication number
- JPH09172330A JPH09172330A JP7331992A JP33199295A JPH09172330A JP H09172330 A JPH09172330 A JP H09172330A JP 7331992 A JP7331992 A JP 7331992A JP 33199295 A JP33199295 A JP 33199295A JP H09172330 A JPH09172330 A JP H09172330A
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- JP
- Japan
- Prior art keywords
- equivalent
- amplifier
- current source
- circuit
- 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.)
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- Optical Communication System (AREA)
Abstract
(57)【要約】
【課題】帯域の広い光受信器を提供することを目的とし
ている。
【解決手段】本発明の光受信器は、一端が直流電圧源に
接続されると共に逆バイアスされ、等価回路が直列に接
続された電流値ｉの電流源及び等価抵抗Ｒと前記電流源
に並列に接続された等価容量ＣJ とで表されるフォトダ
イオードＤ１と、フォトダーオードＤ１の他端が入力端
に接続され、オープンループゲインがＡで表され、反転
出力端ーｖo と前記入力端との間に並列に負帰還抵抗Ｒ
F が接続された増幅器AMP と、前記増幅器の前記入力端
に接続された電流値ｉa の電流源Ｉと等価とみなしうる
補償回路とを備え、前記電流源Ｉの電流の符号は前記入
力端へ流れる向きが正で、その電流値ｉa は
ｉ×（Ｒ＋ＲF ／Ａ）／（Ｒ＋１／（ｊωＣJ ））
と表される電流値以下である。
(57) Abstract: An object is to provide an optical receiver having a wide band. An optical receiver of the present invention has one end connected to a DC voltage source and being reverse-biased, and an equivalent circuit connected in series with a current source having a current value i and an equivalent resistance R and a parallel connection to the current source. The photodiode D1 represented by the equivalent capacitance C J connected to the input terminal and the other end of the photodiode D1 are connected to the input terminal, the open loop gain is represented by A, the inverting output terminal -vo and the input terminal Negative feedback resistance R in parallel with
An amplifier AMP to which F is connected, and a compensation circuit that can be regarded as equivalent to the current source I having a current value ia connected to the input end of the amplifier are provided, and the sign of the current of the current source I is supplied to the input end. The flow direction is positive, and the current value ia thereof is not more than the current value represented by i × (R + R F / A) / (R + 1 / (jωC J )).
Description
【０００１】[0001]
【発明の属する技術分野】この発明は、光受信器に係
り、特に高速、広帯域なフォトダイオードと初段増幅器
の改良に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical receiver, and more particularly to improvement of a high speed and wide band photodiode and a first stage amplifier.
【０００２】[0002]
【従来の技術】従来の例について図面を参照して説明す
る。図４は光受信器の構成を示す図、図５（ａ）は交流
の小信号に関して受光素子であるｐｉｎ型のフォトダイ
オードの等価回路の構成を示す図、図５（ｂ）はそのフ
ォトダイオードの構造を示す図である。2. Description of the Related Art A conventional example will be described with reference to the drawings. 4 is a diagram showing a configuration of an optical receiver, FIG. 5 (a) is a diagram showing a configuration of an equivalent circuit of a pin type photodiode which is a light receiving element for an AC small signal, and FIG. 5 (b) is the photodiode. It is a figure which shows the structure of.
【０００３】図４に示すように、フォトダイオードＤ１
のカソードが正極の電源端子Ｖccに接続されている。フ
ォトダイオードＤ１のアノードは増幅器ＡＭＰの入力に
接続されている。増幅器ＡＭＰはオープンループゲイン
Ａで、その反転出力端は負帰還用の抵抗ＲF を介して入
力端子に接続されている。As shown in FIG. 4, a photodiode D1
Is connected to the positive power source terminal Vcc. The anode of the photodiode D1 is connected to the input of the amplifier AMP. The amplifier AMP has an open loop gain A, and its inverting output terminal is connected to the input terminal through a negative feedback resistor R F.
【０００４】図５（ａ）に示すように、電流源ｉ及び等
価抵抗Ｒは直列に接続されている。等価容量のコンデン
サＣJ は電流源ｉに並列に接続されている。この等価容
量はダイオードＤ１の接合容量と同じである。電流値ｉ
はフォトダイオードＤ１の入射光のパワー（仕事率）に
比例している。As shown in FIG. 5A, the current source i and the equivalent resistance R are connected in series. The capacitor C J having an equivalent capacitance is connected in parallel with the current source i. This equivalent capacitance is the same as the junction capacitance of the diode D1. Current value i
Is proportional to the power (power) of the incident light on the photodiode D1.
【０００５】図５（ｂ）に示すように、フォトダイオー
ドＤ１はｎ型半導体基板２の表面に形成されたｐ層１か
らなるアノードと、半導体基板２の裏面に形成されたｎ
+ 層３とにより構成される。フォトダイオードＤ１の逆
バイアスの電圧が小さい場合、ｎ層２にはｐ層に接して
ｎ+ 層３に向けて空乏層４、それ以外の層５が形成され
る。この空乏層以外の層５に起因する抵抗成分が等価抵
抗Ｒである。As shown in FIG. 5B, the photodiode D1 has an anode formed of the p layer 1 formed on the front surface of the n-type semiconductor substrate 2 and an n formed on the back surface of the semiconductor substrate 2.
+ Layer 3 and. When the reverse bias voltage of the photodiode D1 is small, the depletion layer 4 and the other layer 5 are formed in the n layer 2 in contact with the p layer toward the n + layer 3. The resistance component caused by the layer 5 other than the depletion layer is the equivalent resistance R.
【０００６】電流値ｉの電流源と等価容量Ｃに流れる電
流の和ｉ1 は次式（１）で表される。ただし、電流の符
号は増幅器ＡＭＰの入力端に向かう場合に正とする。 ｉ1 ＝ｉ＋ｊωＣJ （ｖa ーｖi ）…（１） また、フォトダイオードＤ１の等価回路の電流源の電流
値ｉ、等価抵抗Ｒ、等価容量ＣJ の接続点のキルヒホッ
フの法則から次式（２）が成り立つ。The sum i1 of the currents of the current value i and the equivalent capacitance C is expressed by the following equation (1). However, the sign of the current is positive when it goes to the input end of the amplifier AMP. i1 = i + jωC J (va-vi) (1) Further, from the Kirchhoff's law of the connection point of the current value i of the current source of the equivalent circuit of the photodiode D1, the equivalent resistance R, and the equivalent capacitance C J , the following equation (2) is obtained. Holds.
【０００７】 ｖa ／Ｒ＋ｉ＋ｊωＣJ （ｖa ーｖi ）＝０…（２） オープンループゲインＡが十分に大きい増幅器ＡＭＰの
場合、一般に式（３）〜（５）が成り立つ。Va / R + i + jωC J (va−vi) = 0 (2) In the case of the amplifier AMP having a sufficiently large open loop gain A, the equations (3) to (5) generally hold.
【０００８】ｖi ＝ｖo ／Ａ…（３） ｉ2 ＝（ーｖo ーｖi ）／ＲF …（４） １＞＞１／Ａ…（５） また、増幅器ＡＭＰの入力端でのキルヒホッフの法則か
ら、上記式（１）を用いて、次式（６）が成り立つ。Vi = vo / A (3) i2 = (-vo-vi) / R F (4) 1 >> 1 / A (5) Further, from Kirchhoff's law at the input end of the amplifier AMP, By using the above equation (1), the following equation (6) is established.
【０００９】ｉ1 ＋ｉ2 ＝０…（６） この場合、式（１）〜式（４）、式（６）から、式
（５）を用いた近似によって、出力電圧ｖo は次式
（７）で表される。I1 + i2 = 0 ... (6) In this case, the output voltage vo is expressed by the following equation (7) by the approximation using the equation (5) from the equations (1) to (4) and (6). expressed.
【００１０】 ｖo ＝ｉＲF ／（１＋ｊωＣJ （Ｒ＋ＲF ／Ａ））…（７） 従って、高域遮断周波数ｆc は式（８）で与えられる。 ｆc ＝１／（２πＣJ （Ｒ＋ＲF ／Ａ））…（８）Vo = iR F / (1 + jωC J (R + R F / A)) (7) Therefore, the high cutoff frequency fc is given by the equation (8). fc = 1 / (2πC J (R + R F / A)) (8)
【００１１】[0011]
【発明が解決しようとする課題】フォトダイオードＤ１
に十分な逆バイアス電圧が与えられ、空乏層４がｎ+ 層
まで広がっている場合、等価抵抗Ｒを無視することがで
きる。しかし、機器の低電圧化等で十分な逆バイアスが
加えられない場合、等価抵抗Ｒが無視できず周波数特性
が悪くなる。[Problems to be Solved by the Invention] Photodiode D1
When a sufficient reverse bias voltage is applied to the depletion layer 4 and the depletion layer 4 extends to the n + layer, the equivalent resistance R can be ignored. However, when a sufficient reverse bias cannot be applied due to a low voltage of the device, the equivalent resistance R cannot be ignored and the frequency characteristic deteriorates.
【００１２】また、特殊なｐｉｎフォトダイオードの場
合、カソードをアノードと同じ面から取り出すことがあ
る。しかし、厚いｎ層２を貫いて、不純物を拡散してｎ
+ 層を形成することはできないので、等価抵抗Ｒを除く
ことができない。In the case of a special pin photodiode, the cathode may be taken out from the same surface as the anode. However, it penetrates through the thick n-layer 2 and diffuses impurities to n.
Since the + layer cannot be formed, the equivalent resistance R cannot be removed.
【００１３】上記のように等価抵抗Ｒを無視できない場
合は、等価抵抗Ｒがない次式（９）で与えられる高域遮
断周波数ｆc0よりも低くなる。 ｆc0＝１／（２πＣJ ＲF ／Ａ）…（９） 一方、ｎ層２を薄くすれば等価抵抗Ｒを小さくできる
が、光を十分に吸収することができなくなり、従って感
度が悪くなる。例えば、赤外線までの光を十分に吸収す
るためには、ｎ層２の厚さは少なくとも２０μｍ必要で
ある。ｎ層２の不純物濃度が１０13ｃｍ-3（比抵抗１ｋ
Ωｃｍ）の場合、逆バイアス５Ｖまでは空乏層４が２０
μｍとなり問題はない。逆バイアスが１Ｖの場合、空乏
層４は１０μｍにしかならず、厚さ１０μｍ分の層５に
起因する等価抵抗Ｒが生ずる。この場合、受光径を４０
０μｍとすると、等価抵抗Ｒは２．５ｋΩとなる。ま
た、受光素子で伝送される信号の対称として１００Ｍｂ
ｐｓのディジタル信号を考えた場合、オープンループゲ
インは５０程度となり、通常帰還抵抗ＲF は１０ｋΩ程
度となる。この場合の高域遮断周波数ｆc1は式（１０）
で与えられる。When the equivalent resistance R cannot be ignored as described above, it becomes lower than the high cutoff frequency fc0 given by the following equation (9) without the equivalent resistance R. fc0 = 1 / (2πC J R F / A) (9) On the other hand, if the n layer 2 is thinned, the equivalent resistance R can be reduced, but light cannot be sufficiently absorbed, and thus the sensitivity is deteriorated. For example, the thickness of the n-layer 2 needs to be at least 20 μm in order to sufficiently absorb light up to infrared rays. The impurity concentration of the n-layer 2 is 10 13 cm −3 (specific resistance 1 k
Ωcm), the depletion layer 4 is 20 up to a reverse bias of 5V.
It becomes μm and there is no problem. When the reverse bias is 1 V, the depletion layer 4 has a thickness of only 10 μm, and the equivalent resistance R due to the layer 5 having a thickness of 10 μm occurs. In this case, the light receiving diameter should be 40
When it is 0 μm, the equivalent resistance R is 2.5 kΩ. In addition, as the symmetry of the signal transmitted by the light receiving element, 100 Mb
Considering a digital signal of ps, the open loop gain is about 50 and the normal feedback resistance R F is about 10 kΩ. The high cutoff frequency f c1 in this case is calculated by the equation (10).
Given by
【００１４】 ｆc1＝１／（２πＣJ （２．５×１０3 ＋２００））…（１０） このように、等価抵抗Ｒの影響が極めて大きくなり、十
分な周波数特性が得られないという問題があった。この
発明の目的は、ＳＮＲ（信号対ノイズ比）が悪くならず
帯域の広い光受信器を提供することにある。Fc1 = 1 / (2πC J (2.5 × 10 3 +200)) (10) As described above, the effect of the equivalent resistance R becomes extremely large, and there is a problem that sufficient frequency characteristics cannot be obtained. It was An object of the present invention is to provide an optical receiver having a wide band without deteriorating the SNR (signal to noise ratio).
【００１５】[0015]
【課題を解決するための手段】上記課題を解決し目的を
達成するために、この発明の光受信器においては以下の
手段を講じた。請求項１に記載した本発明の光受信器
は、一端が電源に接続されると共に逆バイアスされ、等
価回路が直列に接続された電流値ｉの電流源及び等価抵
抗Ｒと前記電流源に並列に接続された等価容量ＣJ とで
表される受光素子と、前記受光素子の他端が入力端に接
続され、オープンループゲインがＡで表され、反転出力
端と前記入力端との間に負帰還抵抗ＲF が接続された増
幅器とを備えている。前記増幅器の前記入力端に接続さ
れた電流値ｉa の電流源と等価とみなしうる補償回路を
備えている。前記電流源の電流の符号は前記入力端へ流
れる向きが正で、前記電流値ｉa は ｉ×（Ｒ＋ＲF ／Ａ）／（Ｒ＋１／（ｊωＣJ ）） と表される電流値以下である。In order to solve the above problems and achieve the object, the following means are taken in the optical receiver of the present invention. The optical receiver of the present invention according to claim 1 has one end connected to a power source and being reverse biased, and an equivalent circuit connected in series with a current source having a current value i and an equivalent resistance R and the current source connected in parallel. A light receiving element represented by an equivalent capacitance C J connected to the input terminal, the other end of the light receiving element is connected to an input terminal, an open loop gain is represented by A, and an inverting output terminal and the input terminal are connected. And an amplifier to which the negative feedback resistor R F is connected. A compensation circuit that can be regarded as equivalent to a current source having a current value ia connected to the input terminal of the amplifier is provided. The sign of the current of the current source is positive in the direction in which the current flows to the input end, and the current value ia is equal to or less than the current value represented by i × (R + R F / A) / (R + 1 / (jωC J )).
【００１６】上記本発明の光受信器においては、前記等
価抵抗Ｒまたは前記等価容量ＣJ が大きい受光素子であ
っても、前記受光素子から前記増幅器までの周波数特性
が実用上十分に改善される。従って、前記増幅器の前記
反転出力端の信号レベルの低下及びＳＮＲの悪化が生じ
ず、伝送される信号波形が改善される。In the optical receiver of the present invention, the frequency characteristic from the light receiving element to the amplifier is sufficiently improved practically even if the light receiving element has the large equivalent resistance R or the equivalent capacitance C J. . Therefore, the signal level at the inverting output of the amplifier is not lowered and the SNR is not deteriorated, and the transmitted signal waveform is improved.
【００１７】請求項２のように、前記増幅器のオープン
ループゲインＡは１＞＞１／Ａの近似を満たしている。
上記本発明の光受信器においては、前記等価抵抗Ｒまた
は前記等価容量ＣJ が大きい受光素子であっても、前記
受光素子から前記増幅器までの周波数特性が改善され
る。従って、前記増幅器の前記反転出力端の信号レベル
の低下及びＳＮＲの悪化が生じず伝送される信号波形が
改善される。As described in claim 2, the open loop gain A of the amplifier satisfies the approximation of 1 >> 1 / A.
In the above optical receiver of the present invention, the frequency characteristic from the light receiving element to the amplifier is improved even if the light receiving element has the large equivalent resistance R or the equivalent capacitance C J. Therefore, the signal level to be transmitted is improved without lowering the signal level at the inverting output terminal of the amplifier and deteriorating the SNR.
【００１８】請求項３に記載した本発明の光受信器は、
受光量に応じて電流を発生する等価電流源で表される一
つの受光素子と出力端とを有し、前記出力端からみたイ
ンピーダンスがＺである光検出回路と、前記光検出回路
の出力信号が入力端に入力され、反転出力端と前記入力
端との間に負帰還抵抗が接続され、同相出力端を有する
増幅器とを備えている。前記同相出力端の出力信号が入
力され、その出力信号を分圧して分圧出力端から出力す
る分圧回路と、二つの端子の間のインピーダンスが前記
インピーダンスＺと同じで、前記分圧出力端と前記増幅
器の前記入力端との間に直列に接続された正帰還回路と
を備えている。The optical receiver of the present invention according to claim 3 is
A light detection circuit having one light receiving element represented by an equivalent current source that generates a current according to the amount of received light and an output terminal, and an impedance of which is Z when viewed from the output terminal, and an output signal of the light detection circuit. Is input to the input end, a negative feedback resistor is connected between the inverting output end and the input end, and an amplifier having an in-phase output end is provided. The impedance between the voltage dividing circuit, which receives the output signal of the in-phase output terminal, divides the output signal and outputs from the voltage dividing output terminal, is the same as the impedance Z, and the voltage dividing output terminal And a positive feedback circuit connected in series between the amplifier and the input end of the amplifier.
【００１９】上記本発明の光受信器においては、前記同
相出力信号を分圧し前記光検出回路と同じ前記インピー
ダンスＺの前記正帰還回路を介して正帰還することによ
って、補償が行われる。従って、前記受光回路のインピ
ーダスＺの影響が低減され、前記増幅器の前記反転出力
端及び前記同相出力端の信号レベルの低下及びＳＮＲの
悪化が生じることなく周波数特性が改善される。In the above-described optical receiver of the present invention, compensation is performed by dividing the in-phase output signal and performing positive feedback via the positive feedback circuit having the same impedance Z as the photodetector circuit. Therefore, the influence of the impedance Z of the light receiving circuit is reduced, and the frequency characteristics are improved without lowering the signal level and deteriorating the SNR of the inverting output terminal and the in-phase output terminal of the amplifier.
【００２０】請求項４に記載した本発明の光受信器は、
一端が電源に接続されると共に逆バイアスされ、等価回
路が直列に接続された電流源及び等価抵抗と前記電流源
に並列に接続された等価容量とで表される受光素子と、
前記受光素子の他端が入力端に接続され、反転出力端と
前記入力端との間に負帰還抵抗が接続され、同相出力端
を有する増幅器とを備えている。前記同相出力端の出力
信号が入力され、その出力信号を分圧して分圧出力端か
ら出力する分圧回路と、前記分圧出力端と前記増幅器の
前記入力端との間に直列に接続されたコンデンサ及び抵
抗とを備えている。The optical receiver of the present invention according to claim 4 is
One end is connected to a power source and is reverse biased, and a light receiving element represented by a current source and an equivalent resistance in which an equivalent circuit is connected in series, and an equivalent capacitance connected in parallel to the current source,
The other end of the light receiving element is connected to an input end, a negative feedback resistor is connected between an inverting output end and the input end, and an amplifier having an in-phase output end is provided. An output signal of the in-phase output terminal is input, and a voltage divider circuit that divides the output signal and outputs from the voltage dividing output terminal is connected in series between the voltage dividing output terminal and the input terminal of the amplifier. And a capacitor and a resistor.
【００２１】上記本発明の光受信器においては、前記同
相出力信号を分圧し前記コンデンサ及び前記抵抗を介し
て正帰還されて補償が行われる。従って、前記受光素子
の前記等価抵抗Ｒ及び前記等価容量ＣJ の影響が低減さ
れ、前記増幅器の前記反転出力端及び前記同相出力端の
信号レベルの低下及びＳＮＲの悪化が生じることなく周
波数特性が改善される。In the optical receiver of the present invention, the in-phase output signal is divided and positively fed back through the capacitor and the resistor for compensation. Therefore, the influence of the equivalent resistance R and the equivalent capacitance C J of the light receiving element is reduced, and the frequency characteristics are reduced without lowering the signal level of the inverting output terminal and the common mode output terminal of the amplifier and deteriorating the SNR. Be improved.
【００２２】請求項５に示すように、前記増幅器のオー
プンループゲインは１＞＞１／Ａの近似式を満たすＡで
あり、前記コンデンサの容量値は前記等価容量の値と同
じで、前記抵抗の抵抗値は前記等価抵抗の値と同じであ
る。According to a fifth aspect of the present invention, the open loop gain of the amplifier is A which satisfies the approximate expression of 1 >> 1 / A, the capacitance value of the capacitor is the same as the equivalent capacitance value, and the resistance is the same. Has the same resistance value as the equivalent resistance value.
【００２３】上記本発明の光受信器においては、前記同
相出力信号が正帰還されて高域成分が補償される。従っ
て、前記増幅器の前記反転出力端及び前記同相出力端の
信号は前記受光素子の前記等価抵抗Ｒ及び前記等価容量
ＣJ に無関係となり、前記増幅器の前記反転出力端及び
前記同相出力端の信号レベルの低下及びＳＮＲの悪化が
生じることなく周波数特性が改善される。In the optical receiver of the present invention, the in-phase output signal is positively fed back to compensate for the high frequency component. Therefore, the signals at the inverting output terminal and the in-phase output terminal of the amplifier become irrelevant to the equivalent resistance R and the equivalent capacitance C J of the light receiving element, and the signal levels at the inverting output terminal and the in-phase output terminal of the amplifier. Of frequency and deterioration of SNR do not occur, and the frequency characteristic is improved.
【００２４】請求項６に記載した本発明の光受信器は、
エミッタが電源端子に接続された第１トランジスタと、
エミッタが前記第１トランジスタのエミッタに接続さ
れ、ベースが前記第１トランジスタのベースに接続され
た第２トランジスタとを備えている。一端が前記第１ト
ランジスタのコレクタ及びベースに接続されると共に逆
バイアスされ、等価回路が直列に接続された等価抵抗及
び電流源と前記電流源に並列に接続された等価容量とで
表される受光素子と、前記受光素子の他端が入力端に接
続され、反転出力端と前記入力端との間に負帰還抵抗が
接続された増幅器とを備えている。前記第２トランジス
タのコレクタと前記増幅器の入力端との間に接続された
コンデンサと、前記コンデンサと前記第２トランジスタ
のコレクタとの接続点と接地端子及び別の電源端子のい
ずれか一方との間に接続された抵抗とを備えている。上
記本発明の光受信器においては、前記第１、第２トラン
ジスタがカレントミラ回路を構成しており、容易に前記
受光素子の高域補償が行われる。The optical receiver of the present invention according to claim 6 is:
A first transistor whose emitter is connected to the power supply terminal,
A second transistor having an emitter connected to the emitter of the first transistor and a base connected to the base of the first transistor. One end is connected to the collector and the base of the first transistor and is reverse biased, and an equivalent circuit is represented by an equivalent resistance and a current source connected in series and an equivalent capacitance connected in parallel to the current source. An element and an amplifier in which the other end of the light receiving element is connected to the input end and a negative feedback resistor is connected between the inverting output end and the input end are provided. Between a capacitor connected between the collector of the second transistor and the input terminal of the amplifier, between a connection point of the capacitor and the collector of the second transistor, and one of a ground terminal and another power supply terminal. And a resistor connected to. In the above-described optical receiver of the present invention, the first and second transistors form a current mirror circuit, and the high frequency compensation of the light receiving element is easily performed.
【００２５】[0025]
【発明の実施の形態】以下、本発明の実施の形態につい
て図面を参照して説明する。尚、図４、図５と同一部分
には同一符号を付し、異なる部分についてのみ説明す
る。 （第１の実施の形態）図１（ａ）に示すように、この発
明の特徴は、受光素子であるｐｉｎ型のフォトダイード
Ｄ１のアノードと増幅器ＡＭＰの入力端との接続点及び
接地間に電流値ｉa の電流源Ｉと等価とみなしうる回路
を接続していることである。増幅器ＡＭＰの入力端に向
かう場合、この電流源Ｉの電流の符号を正としている。Embodiments of the present invention will be described below with reference to the drawings. The same parts as those in FIGS. 4 and 5 are designated by the same reference numerals, and only different parts will be described. (First Embodiment) As shown in FIG. 1A, the present invention is characterized in that a current is applied between a connection point between an anode of a pin type photodiode D1 which is a light receiving element and an input end of an amplifier AMP and ground. That is, a circuit that can be regarded as equivalent to the current source I having the value ia is connected. When going to the input end of the amplifier AMP, the sign of the current of the current source I is positive.
【００２６】図１（ｂ）は図１（ａ）の等価回路を示し
ている。この等価回路において、電流値ｉa は次式（１
１）のように表される。 ｉa ＝ｉ×（Ｒ＋ＲF ／Ａ）／（Ｒ＋１／（ｊωＣJ ））…（１１） この場合、増幅器ＡＭＰの出力端の電圧ｖo を入力信号
である等価回路の電流源の電流値ｉで表した式は周波数
の関数とならない。次にこの計算の概略を示す。FIG. 1 (b) shows an equivalent circuit of FIG. 1 (a). In this equivalent circuit, the current value ia is expressed by the following equation (1
It is expressed as 1). ia = i × (R + R F / A) / (R + 1 / (jωC J )) (11) In this case, the voltage vo at the output end of the amplifier AMP is represented by the current value i of the current source of the equivalent circuit as an input signal. The formula is not a function of frequency. The outline of this calculation is shown below.
【００２７】まず、増幅器ＡＭＰの入力端におけるキル
ヒホッフの法則から次式（１２）が成り立つ。 ｉ1 ＋ｉ2 ＋ｉa ＝０…（１２） 従って、式（１）、式（４）、式（１２）から次式（１
３）が成り立つ。First, the following equation (12) is established from Kirchhoff's law at the input end of the amplifier AMP. i1 + i2 + ia = 0 (12) Therefore, from the equation (1), the equation (4), and the equation (12), the following equation (1
3) holds.
【００２８】 ｉ＋ｊωＣJ （ｖa ーｖi ）＋（ーｖo ーｖi ）／ＲF ＋ｉa ＝０ …（１３） 上記式（１３）、式（２）、式（３）、式（１１）から
ｖa 、ｖi 、ｉa を消去する。まず、式（３）のｖi を
式（１３）代入すると共に式（５）を用いて近似すると
次式（１４）となる。I + jωC J (va −vi) + (− vo −vi) / R F + ia = 0 (13) The above formula (13), formula (2), formula (3), and formula (11) to va, Erase vi and ia. First, when v i in equation (3) is substituted into equation (13) and approximation is performed using equation (5), the following equation (14) is obtained.
【００２９】 ｉ＋ｊωＣJ （ｖa ーｖo ／Ａ）−ｖo ／ＲF ＋ｉa ＝０…（１４） 次に、式（２）、式（３）、式（１１）を用いて式（１
５）が導き出される。 ｖo ＝ｉＲF …（１５） 式（１５）に表されるように、ｖo は周波数の関数では
なく、受光素子の等価抵抗Ｒ及び等価容量ＣJ による影
響は全く生じない。尚、電流源Ｉの電流値ｉaは式（１
１）の右辺で表される電流の値に限らず、式（１１）の
右辺で表される電流値以下であればよい。電流値ｉa と
しては、式（１１）の右辺で表される電流値に近い値が
好適である。この場合、上記電流源Ｉの電流値ｉa に応
じてフォトダイオードＤ１の周波数特性が補償され改善
される。I + jωC J (va-vo / A) -vo / R F + ia = 0 ... (14) Next, using equation (2), equation (3), and equation (11), equation (1
5) is derived. vo = iR F (15) As represented by the equation (15), vo is not a function of frequency, and the equivalent resistance R and the equivalent capacitance C J of the light receiving element have no influence. The current value ia of the current source I can be calculated by the equation (1
The current value is not limited to the current value represented by the right side of 1), and may be equal to or less than the current value represented by the right side of Expression (11). As the current value ia, a value close to the current value represented by the right side of Expression (11) is suitable. In this case, the frequency characteristic of the photodiode D1 is compensated and improved according to the current value ia of the current source I.
【００３０】尚、上記の光受光素子はｐｉｎ型フォトダ
イオードに限らず、ジャンクション抵抗が大きい受光素
子ならよい。第１の実施の形態においては、等価抵抗Ｒ
または等価容量ＣJ が大きい受光素子、例えばフォトダ
イードＤ１であっても、その信号の高域成分が補償され
る。つまり、フォトダイオードＤ１から増幅器ＡＭＰま
での周波数特性が改善される。従って、増幅器ＡＭＰの
出力端の信号レベル及びＳＮＲが低下することなくその
出力の信号波形が改善される。結局、実施の形態の後段
には信号波形を改善するための回路が不要となる。The above light receiving element is not limited to the pin type photodiode, but may be any light receiving element having a large junction resistance. In the first embodiment, the equivalent resistance R
Alternatively, even in a light receiving element having a large equivalent capacitance C J , for example, the photodiode D1, the high frequency component of the signal is compensated. That is, the frequency characteristic from the photodiode D1 to the amplifier AMP is improved. Therefore, the signal level of the output of the amplifier AMP is improved without lowering the signal level and SNR at the output end. After all, a circuit for improving the signal waveform is not required in the latter stage of the embodiment.
【００３１】尚、式（１６）が成り立つ場合、電流値ｉ
a の電流源Ｉの代わりに次式（１７）の電流値ｉb の電
流源と等価とみなしうる回路を用いても同様に、式（１
５）を導き出すことができる。When the equation (16) is satisfied, the current value i
Even if a circuit that can be regarded as equivalent to the current source having the current value ib of the following equation (17) is used instead of the current source I of a, the equation (1
5) can be derived.
【００３２】Ｒ＞＞ＲF ／Ａ…（１６） ｉb ＝ｉＲ／（Ｒ＋１／（ｊωＣJ ））…（１７） 計算の概略を示す。式（１）、式（３）、式（４）、式
（１２）でｉa をｉbに置き換えたキルヒホッフの法則
による式（ｉ1 ＋ｉ2 ＋ｉb ＝０）、式（１７）、及
び、式（５）による近似を用いると次式（１８）が成り
立つ。R >> R F / A (16) ib = iR / (R + 1 / (jωC J )) (17) An outline of the calculation is shown. Expressions (i1 + i2 + ib = 0) according to Kirchhoff's law in which ia is replaced with ib in Expressions (1), (3), (4), and (12), Expression (17), and Expression (5) When the approximation by is used, the following equation (18) is established.
【００３３】 ｉ＋ｊωＣJ （ｖa ーｖo ／Ａ）ーｖo ／ＲF ＋ｉＲ／（Ｒ＋１／（ｊωＣJ ））＝０…（１８） この式（１８）と式（２）、式（３）から次式（１９）
となる。I + jωC J (va−vo / A) −vo / R F + iR / (R + 1 / (jωC J )) = 0 (18) From this equation (18), equation (2), and equation (3), Formula (19)
Becomes
【００３４】 ｖo ＝ｉＲF （１＋ｊωＣJ Ｒ）／（１＋ｊωＣJ （Ｒ＋ＲF ／Ａ）） …（１９） この式（１９）に式（１６）の近似を用いると、式（１
５）が導き出される。 （第２の実施の形態）図２（ａ）に第２実施の形態の回
路構成を示す。図１と同一部分には同一符号を付し、説
明は省略する。Vo = iR F (1 + jωC J R) / (1 + jωC J (R + R F / A)) (19) When the approximation of the formula (16) is applied to the formula (19), the formula (1
5) is derived. (Second Embodiment) FIG. 2A shows the circuit configuration of the second embodiment. The same parts as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted.
【００３５】図２（ａ）に示すように、増幅器ＡＭＰの
同相出力ｖo が分圧回路６で分圧され分圧出力端７から
出力される。その分圧出力端７と増幅器ＡＭＰの入力端
との間に、コンデンサＣJ1、抵抗ＲJ1の直列回路が接続
される。式（２０）のように、コンデンサＣJ1の容量は
ダイオードＤ１の等価容量ＣJ と同一であり、抵抗ＲJ1
の抵抗値はダイオードＤ１の抵抗Ｒと同一である。この
場合、コンデンサＣJ1、抵抗ＲJ1の直列回路のインピー
ダンスは増幅器ＡＭＰの入力端からみたフォトダイオー
ドＤ１のインピーダンスと同じである。As shown in FIG. 2A, the in-phase output vo of the amplifier AMP is divided by the voltage dividing circuit 6 and output from the voltage dividing output terminal 7. A series circuit of a capacitor C J1 and a resistor R J1 is connected between the voltage dividing output terminal 7 and the input terminal of the amplifier AMP. As in equation (20), the capacitance of the capacitor C J1 is the same as the equivalent capacitance C J of the diode D1, and the resistance R J1
Has the same resistance value as the resistance R of the diode D1. In this case, the impedance of the series circuit of the capacitor C J1 and the resistor R J1 is the same as the impedance of the photodiode D1 viewed from the input end of the amplifier AMP.
【００３６】ＲJ1＝Ｒ、ＣJ1＝ＣJ …（２０） 接続された状態の分圧回路６の分圧比ｒは式（２１）の
ようになっている。 ｒ＝（Ｒ＋２ＲF ／Ａ）／ＲF …（２１） また、抵抗ＲJ1から増幅器ＡＭＰの入力端に流れる電流
値ｉ3 は次式（２２）で表される。R J1 = R, C J1 = C J (20) The voltage division ratio r of the voltage dividing circuit 6 in the connected state is represented by the equation (21). r = (R + 2R F / A) / R F (21) Further, the current value i3 flowing from the resistor R J1 to the input terminal of the amplifier AMP is expressed by the following equation (22).
【００３７】 ｉ3 ＝（ｒ×ｖo ーｖi ）／（ＲJ1＋１／（ｊωＣJ1））…（２２） 第１の実施の形態の場合と同様に、増幅器ＡＭＰの入力
端におけるキルヒホッフの法則による式（ｉ1 ＋ｉ2 ＋
ｉ3 ＝０）を用い、式（１）、式（４）から式（２３）
となる。I3 = (r × vo−vi) / (R J1 + 1 / (jωC J1 )) (22) As in the case of the first embodiment, the expression according to Kirchhoff's law at the input end of the amplifier AMP. (I1 + i2 +
i3 = 0), and the equations (1), (4) to (23) are used.
Becomes
【００３８】 ｉ＋ｊωＣJ （ｖa ーｖi ）＋（ーｖo ーｖi ）／ＲF ＋ｉ3 ＝０ …（２３） 式（２）、式（３）、式（２１）〜式（２３）からｖi
、ｖa 、ｉ3 、ｒを消去する。第１の実施の形態の場
合と同様に、まず、式（２２）及び式（３）のｖi を式
（２３）に代入すると共に、式（５）を用いて近似する
と式（２４）になる。I + jωC J (va −vi) + (− vo −vi) / R F + i3 = 0 (23) Formula (2), Formula (3), Formula (21) to Formula (23) to vi
, Va, i3, r are erased. As in the case of the first embodiment, first, vi of Expressions (22) and (3) is substituted into Expression (23), and approximation is performed using Expression (5) to obtain Expression (24). .
【００３９】 ｉ＋ｊωＣJ （ｖa ーｖo ／Ａ）ーｖo ／ＲF ＋（ｒ×ｖo ーｖo ／Ａ）／（ＲJ1＋１／（ｊωＣJ1））＝０…（２４） この式（２４）と式（２）、式（３）、式（２１）から
式（１５）の関係式が計算される。I + jωC J (va−vo / A) −vo / R F + (r × vo−vo / A) / (R J1 + 1 / (jωC J1 )) = 0 ... (24) With this equation (24) The relational expression of Expression (15) is calculated from Expression (2), Expression (3), and Expression (21).
【００４０】従って、第１の実施の形態と同様に、ｖo
は周波数の関数とはならず、受光素子の等価抵抗Ｒ及び
等価容量ＣJ による影響は生じない。また、この時、式
（３）、式（１５）、式（２１）を式（２２）に代入す
ると次式（２５）が成り立っていることがわかる。Therefore, as in the first embodiment, vo
Does not become a function of frequency, and is not affected by the equivalent resistance R and equivalent capacitance C J of the light receiving element. Further, at this time, it is understood that the following expression (25) is established by substituting the expression (3), the expression (15), and the expression (21) into the expression (22).
【００４１】ｉ3 ＝ｉa …（２５） 次に実験例を示す。オープンループゲインＡ＝５０、Ｒ
＝２．５ｋΩ（または２．７ｋΩ）、ＣJ ＝２ｐＦ、Ｒ
F ＝１０ｋΩとすると、分圧比は０．２９（または０．
３１）とすればよいことがわかる。図２（ｂ）に示すよ
うに、実際の分圧回路６は通常の抵抗分圧でよい。つま
り、抵抗Ｒ1 及び抵抗Ｒ2 が増幅器ＡＭＰの同相出力端
ｖo と接地端子との間に直列に接続されている。抵抗Ｒ
1 と抵抗Ｒ2 の接続点が分圧出力端７となる。尚、分圧
出力端７からの出力信号をバッファを介して出力しても
よい。回路定数としてＪＩＳ規格の汎用部品を使うと、
抵抗Ｒ1 は６８０Ω、抵抗Ｒ2 は２７０Ωとすればよ
い。計算値（分圧比０．２９または０．３１）と実際の
回路定数（分圧比０．２８）とにずれ（３〜１０％）が
生じても実際上問題とならず、フォトダイオードＤ１の
周波数特性の補償は十分な効果を有する。また、この実
施の形態の構成は式（２１）からＲF をＲより大きくで
きる場合に適している。尚、抵抗ＲとコンデンサＣJ1と
のインピーダンスに比べて、抵抗Ｒ1 、Ｒ2 の抵抗値は
小さい値がよい。I3 = ia (25) Next, an experimental example will be shown. Open loop gain A = 50, R
= 2.5 kΩ (or 2.7 kΩ), C J = 2 pF, R
When F = 10 kΩ, the voltage division ratio is 0.29 (or 0.
It can be seen that 31) is sufficient. As shown in FIG. 2B, the actual voltage dividing circuit 6 may be a normal resistance voltage dividing. That is, the resistor R1 and the resistor R2 are connected in series between the in-phase output terminal vo of the amplifier AMP and the ground terminal. Resistance R
The connection point between 1 and the resistor R2 becomes the voltage division output terminal 7. The output signal from the voltage division output end 7 may be output via a buffer. If you use JIS standard general-purpose parts as circuit constants,
The resistance R1 may be 680Ω and the resistance R2 may be 270Ω. Even if the calculated value (divided voltage ratio 0.29 or 0.31) and the actual circuit constant (divided voltage ratio 0.28) are deviated (3 to 10%), there is no practical problem and the frequency of the photodiode D1 Characteristic compensation has a sufficient effect. Further, the configuration of this embodiment is suitable when R F can be made larger than R from the equation (21). The resistance values of the resistors R1 and R2 are preferably smaller than the impedances of the resistor R and the capacitor CJ1.
【００４２】第２の実施の形態においては、増幅器ＡＭ
Ｐの出力信号の高域成分が正帰還され、その高域成分が
補償される。従って、フォトダイオードＤ１の等価抵抗
Ｒ及び等価容量ＣJ が周波数特性に与える影響が低減さ
れる。また、増幅器ＡＭＰの出力端の信号レベルが低下
し及びそのＳＮＲが劣化することなく、及び信号波形が
改善される。 （変形例）図３は上記実施の形態の別の回路構成例を示
す図である。図１または図２と同一部分には同一符号を
付し、説明は省略する。この回路は式（１６）の条件が
成り立つ場合に有効である。In the second embodiment, the amplifier AM
The high frequency component of the output signal of P is positively fed back, and the high frequency component is compensated. Therefore, the influence of the equivalent resistance R and the equivalent capacitance C J of the photodiode D1 on the frequency characteristics is reduced. Further, the signal level at the output end of the amplifier AMP is not lowered and its SNR is not deteriorated, and the signal waveform is improved. (Modification) FIG. 3 is a diagram showing another circuit configuration example of the above embodiment. The same parts as those in FIG. 1 or FIG. This circuit is effective when the condition of Expression (16) is satisfied.
【００４３】カレントミラー回路を構成するＰＮＰ型ト
ランジスタＱ１、Ｑ２のエミッタは共に正極性電源Ｖcc
に接続されている。トランジスタＱ１のコレクタ、ベー
ス及びトランジスタＱ２のベースはフォトダイオードＤ
１のカソードに接続されている。前記トランジスタＱ２
のコレクタと増幅器ＡＭＰの入力端との間にはコンデン
サＣJ1が接続され、トランジスタＱ２のコレクタと接地
との間に抵抗ＲJ1が接続されている。尚、抵抗ＲJ1がト
ランジスタＱ２のコレクタと別の電源端子との間に接続
されて、バイアス回路を兼ねるようにしてもよい。コン
デンサＣJ1は等価容量ＣJ に近い値を選ぶ。及び、抵抗
ＲJ1は抵抗Ｒに近い値を選ぶ。The emitters of PNP type transistors Q1 and Q2 which compose the current mirror circuit are both positive polarity power source Vcc.
It is connected to the. The collector and base of the transistor Q1 and the base of the transistor Q2 are the photodiode D.
1 cathode. The transistor Q2
A capacitor C J1 is connected between the collector of the transistor Q2 and the input terminal of the amplifier AMP, and a resistor R J1 is connected between the collector of the transistor Q2 and the ground. The resistor R J1 may be connected between the collector of the transistor Q2 and another power supply terminal so as to also serve as a bias circuit. For the capacitor C J1 , a value close to the equivalent capacitance C J is selected. And, as the resistance R J1 , a value close to the resistance R is selected.
【００４４】例えば、この場合、回路定数はオープンル
ープゲインＡ＝５０、ＲJ1＝Ｒ＝２．５ｋΩ（または
２．７ｋΩ）、ＣJ1＝ＣJ ＝２ｐＦ、ＲF ＝１０ｋΩと
する。この構成によっても第１の実施の形態と同様に、
フォトダイオードＤ１の等価抵抗Ｒ及び等価容量ＣJ に
よる周波数特性への影響が低減され、信号波形が改善さ
れる。また、分圧比が式（１６）を満たす場合、つまり
Ｒが比較的大きい値の場合に適してる。また、等価容量
ＣJ に流れる電流の値が大きくない場合に適している。
この場合、カレントミラー回路Ｑ１、Ｑ２、抵抗ＲJ1、
コンデンサＣJ1によって、近似的に前述の実施の形態の
効果があり、つまり、簡易に受光素子の周波数特性の補
償が行われる。For example, in this case, the circuit constants are open loop gain A = 50, R J1 = R = 2.5 kΩ (or 2.7 kΩ), C J1 = C J = 2 pF, and R F = 10 kΩ. With this configuration, as in the first embodiment,
The influence of the equivalent resistance R and the equivalent capacitance C J of the photodiode D1 on the frequency characteristics is reduced, and the signal waveform is improved. Further, it is suitable when the voltage division ratio satisfies the expression (16), that is, when R has a relatively large value. It is also suitable when the value of the current flowing through the equivalent capacitance C J is not large.
In this case, the current mirror circuits Q1 and Q2, the resistor R J1 ,
By the capacitor C J1 , the effect of the above-described embodiment is approximately obtained, that is, the frequency characteristic of the light receiving element is easily compensated.
【００４５】尚、受光素子及びトランジスタＱ１、Ｑ２
に接続する正極性電源は負極性電源でよく、この場合ト
ランジスタＱ１、Ｑ２はＮＰＮ型となる。尚、第２、第
３の実施例でＲJ1、ＣJ1はＪＩＳ規格の汎用部品を使用
してもよい。Incidentally, the light receiving element and the transistors Q1 and Q2
The positive power source to be connected to may be a negative power source, and in this case, the transistors Q1 and Q2 are of NPN type. Incidentally, in the second and third embodiments, R J1 and C J1 may be general-purpose parts of JIS standard.
【００４６】[0046]
【発明の効果】以上説明したように、この発明によれ
ば、ＳＮＲが悪くならず帯域の広い光受信器を提供でき
る。As described above, according to the present invention, it is possible to provide an optical receiver having a wide band without deteriorating the SNR.
【図１】本発明の第１の実施の形態の一例に係る光受信
器を説明する図。FIG. 1 is a diagram illustrating an optical receiver according to an example of a first embodiment of the present invention.
【図２】本発明の第２の実施の形態の一例に係る光受信
器の構成を示す図。FIG. 2 is a diagram showing a configuration of an optical receiver according to an example of a second embodiment of the present invention.
【図３】本発明の実施の形態の一例に係る光受信器の構
成を示す図。FIG. 3 is a diagram showing a configuration of an optical receiver according to an example of an embodiment of the present invention.
【図４】従来の光受信器の一例の構成を示す図。FIG. 4 is a diagram showing a configuration of an example of a conventional optical receiver.
【図５】本発明及び従来の受光素子を説明するための
図。FIG. 5 is a diagram for explaining the present invention and a conventional light receiving element.
Ｄ１…フォトダイード、ＣJ …等価容量、Ｒ…等価抵
抗、ＣJ1、ＣJ2…コンデンサ、ＲJ1、ＲJ2、ＲF 、Ｒ1
、Ｒ2 …抵抗、６…分圧回路、ＡＭＰ…増幅器、Ｑ
１、Ｑ２…トランジスタ、Ｉ…電流源と等価な回路、
ｉ、ｉa 、ｉb …等価回路の電流源。D1 ... Photo diode, C J ... Equivalent capacitance, R ... Equivalent resistance, C J1 , C J2 ... Capacitor, R J1 , R J2 , R F , R1
, R2 ... Resistor, 6 ... Voltage dividing circuit, AMP ... Amplifier, Q
1, Q2 ... Transistor, I ... Circuit equivalent to current source,
i, ia, ib ... Current source of equivalent circuit.
フロントページの続き (51)Int.Cl.6 識別記号 庁内整理番号 ＦＩ 技術表示箇所 Ｈ０４Ｂ 10/06 Continuation of front page (51) Int.Cl. 6 Identification code Office reference number FI technical display area H04B 10/06
Claims (6)
され、等価回路が直列に接続された電流値ｉの電流源及
び等価抵抗Ｒと前記電流源に並列に接続された等価容量
ＣJとで表される受光素子と、 前記受光素子の他端が入力端に接続され、オープンルー
プゲインがＡで表され、反転出力端と前記入力端との間
に負帰還抵抗ＲF が接続された増幅器と、 前記増幅器の前記入力端に接続された電流値ｉa の電流
源と等価とみなしうる補償回路とを備え、 前記電流源の電流の符号は前記入力端へ流れる向きが正
で、前記電流値ｉa は ｉ×（Ｒ＋ＲF ／Ａ）／（Ｒ＋１／（ｊωＣJ ）） と表される電流値以下であることを特徴とする光受信
器。1. A current source having a current value i, one end of which is connected to a power source and is reverse biased, and an equivalent circuit is connected in series, and an equivalent resistance R, and an equivalent capacitance C J connected in parallel to the current source. And the other end of the light receiving element is connected to the input end, the open loop gain is represented by A, and the negative feedback resistor R F is connected between the inverting output end and the input end. An amplifier and a compensation circuit that can be regarded as equivalent to a current source having a current value ia connected to the input end of the amplifier are provided, and the sign of the current of the current source is positive in the direction in which the current flows to the input end. An optical receiver characterized in that a value ia is equal to or less than a current value represented by i × (R + R F / A) / (R + 1 / (jωC J )).
＞＞１／Ａの近似を満たすことを特徴とする請求項１に
記載の光受信器。2. The open loop gain A of the amplifier is 1
The optical receiver according to claim 1, wherein the approximation of >> 1 / A is satisfied.
で表される一つの受光素子と出力端とを有し、前記出力
端からみたインピーダンスがＺである光検出回路と、 前記光検出回路の出力信号が入力端に入力され、反転出
力端と前記入力端との間に負帰還抵抗が接続され、同相
出力端を有する増幅器と、 前記同相出力端の出力信号が入力され、その出力信号を
分圧して分圧出力端から出力する分圧回路と、 二つの端子の間のインピーダンスが前記インピーダンス
Ｚと同じで、前記分圧出力端と前記増幅器の前記入力端
との間に直列に接続された正帰還回路とを備えたことを
特徴とする光受信器。3. A photodetector circuit having one light receiving element represented by an equivalent current source that generates a current according to the amount of received light and an output terminal, and having an impedance of Z when viewed from the output terminal; The output signal of the detection circuit is input to the input end, a negative feedback resistor is connected between the inverting output end and the input end, an amplifier having an in-phase output end, and the output signal of the in-phase output end is input, A voltage divider circuit that divides the output signal and outputs the voltage from the voltage divider output terminal, and an impedance between the two terminals is the same as the impedance Z, and is connected in series between the voltage divider output terminal and the input terminal of the amplifier. And a positive feedback circuit connected to the optical receiver.
され、等価回路が直列に接続された電流源及び等価抵抗
と前記電流源に並列に接続された等価容量とで表される
受光素子と、 前記受光素子の他端が入力端に接続され、反転出力端と
前記入力端との間に負帰還抵抗が接続され、同相出力端
を有する増幅器と、 前記同相出力端の出力信号が入力され、その出力信号を
分圧して分圧出力端から出力する分圧回路と、 前記分圧出力端と前記増幅器の前記入力端との間に直列
に接続されたコンデンサ及び抵抗とを備えていることを
特徴とする光受信器。4. A light receiving element, one end of which is connected to a power supply and is reverse-biased, and which is represented by a current source and an equivalent resistance in which an equivalent circuit is connected in series, and an equivalent capacitance connected in parallel to the current source. The other end of the light receiving element is connected to an input end, a negative feedback resistor is connected between an inverting output end and the input end, and an amplifier having an in-phase output end, and an output signal of the in-phase output end are input. A voltage dividing circuit that divides the output signal and outputs the divided signal from a voltage dividing output terminal; and a capacitor and a resistor connected in series between the voltage dividing output terminal and the input terminal of the amplifier. Optical receiver characterized by.
＞１／Ａの近似式を満たすＡであり、 前記コンデンサの容量値は前記等価容量の値と同じで、
前記抵抗の抵抗値は前記等価抵抗の値と同じであること
を特徴とする請求項４に記載の光受信器。5. The open loop gain of the amplifier is 1>
A satisfying an approximate expression of> 1 / A, the capacitance value of the capacitor is the same as the equivalent capacitance value,
The optical receiver according to claim 4, wherein the resistance value of the resistor is the same as the equivalent resistance value.
ンジスタと、 エミッタが前記第１トランジスタのエミッタに接続さ
れ、ベースが前記第１トランジスタのベースに接続され
た第２トランジスタと、 一端が前記第１トランジスタのコレクタ及びベースに接
続されると共に逆バイアスされ、等価回路が直列に接続
された等価抵抗及び電流源と前記電流源に並列に接続さ
れた等価容量とで表される受光素子と、 前記受光素子の他端が入力端に接続され、反転出力端と
前記入力端との間に負帰還抵抗が接続された増幅器と、 前記第２トランジスタのコレクタと前記増幅器の入力端
との間に接続されたコンデンサと、 前記コンデンサと前記第２トランジスタのコレクタとの
接続点と接地端子及び別の電源端子のいずれか一方との
間に接続された抵抗とを備えたことを特徴とする光受信
器。6. A first transistor having an emitter connected to a power supply terminal; a second transistor having an emitter connected to the emitter of the first transistor and having a base connected to the base of the first transistor; A light receiving element which is connected to the collector and base of the first transistor and is reverse biased, and which is represented by an equivalent resistance and a current source in which an equivalent circuit is connected in series, and an equivalent capacitance connected in parallel to the current source; The other end of the light receiving element is connected to the input end, and an amplifier having a negative feedback resistor connected between the inverting output end and the input end, and between the collector of the second transistor and the input end of the amplifier. Connected between the connected capacitor, the connection point between the capacitor and the collector of the second transistor, and one of the ground terminal and another power supply terminal. Optical receiver is characterized in that a resistor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33199295A JP3410888B2 (en) | 1995-12-20 | 1995-12-20 | Optical receiver |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33199295A JP3410888B2 (en) | 1995-12-20 | 1995-12-20 | Optical receiver |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH09172330A true JPH09172330A (en) | 1997-06-30 |
| JP3410888B2 JP3410888B2 (en) | 2003-05-26 |
Family
ID=18249936
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP33199295A Expired - Fee Related JP3410888B2 (en) | 1995-12-20 | 1995-12-20 | Optical receiver |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3410888B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2002045300A1 (en) * | 2000-12-01 | 2002-06-06 | Transmode Systems Ab | A transmitter-receiver device and a communication system |
| WO2002045255A1 (en) * | 2000-12-01 | 2002-06-06 | Transmode Systems Ab | Amplifier circuit, an optical communication system and a method of controlling amplification |
| CN117849420A (en) * | 2024-03-08 | 2024-04-09 | 上海昇贻半导体科技有限公司 | Heavy current protection circuit in photoelectric TIA circuit |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03171908A (en) * | 1989-11-30 | 1991-07-25 | Toshiba Corp | Light receiving circuit |
| JPH06350351A (en) * | 1993-06-08 | 1994-12-22 | Sharp Corp | Light receiving amplifier |
| JPH0739112U (en) * | 1993-12-17 | 1995-07-14 | 新日本無線株式会社 | AC signal optical amplifier |
| JPH07212147A (en) * | 1994-01-19 | 1995-08-11 | Fujitsu Ltd | Current-voltage conversion circuit |
| JPH07226631A (en) * | 1994-02-16 | 1995-08-22 | Ricoh Co Ltd | Optical signal detection circuit |
-
1995
- 1995-12-20 JP JP33199295A patent/JP3410888B2/en not_active Expired - Fee Related
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03171908A (en) * | 1989-11-30 | 1991-07-25 | Toshiba Corp | Light receiving circuit |
| JPH06350351A (en) * | 1993-06-08 | 1994-12-22 | Sharp Corp | Light receiving amplifier |
| JPH0739112U (en) * | 1993-12-17 | 1995-07-14 | 新日本無線株式会社 | AC signal optical amplifier |
| JPH07212147A (en) * | 1994-01-19 | 1995-08-11 | Fujitsu Ltd | Current-voltage conversion circuit |
| JPH07226631A (en) * | 1994-02-16 | 1995-08-22 | Ricoh Co Ltd | Optical signal detection circuit |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2002045300A1 (en) * | 2000-12-01 | 2002-06-06 | Transmode Systems Ab | A transmitter-receiver device and a communication system |
| WO2002045255A1 (en) * | 2000-12-01 | 2002-06-06 | Transmode Systems Ab | Amplifier circuit, an optical communication system and a method of controlling amplification |
| US6943630B2 (en) | 2000-12-01 | 2005-09-13 | Transmode Systems Ab | Amplifier circuit, an optical communication system and a method of controlling amplification |
| US7212740B2 (en) | 2000-12-01 | 2007-05-01 | Transmode Systems Ab | Transmitter-receiver device and a communication system |
| CN117849420A (en) * | 2024-03-08 | 2024-04-09 | 上海昇贻半导体科技有限公司 | Heavy current protection circuit in photoelectric TIA circuit |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3410888B2 (en) | 2003-05-26 |
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