JPH11340925A - Semiconductor integrated circuit for receiving light - Google Patents
Semiconductor integrated circuit for receiving lightInfo
- Publication number
- JPH11340925A JPH11340925A JP10147399A JP14739998A JPH11340925A JP H11340925 A JPH11340925 A JP H11340925A JP 10147399 A JP10147399 A JP 10147399A JP 14739998 A JP14739998 A JP 14739998A JP H11340925 A JPH11340925 A JP H11340925A
- Authority
- JP
- Japan
- Prior art keywords
- light receiving
- receiving element
- current
- output
- light
- 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
Landscapes
- Optical Communication System (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、半導体基板上に発
生する寄生容量の悪影響を低減する受光用半導体集積回
路に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light receiving semiconductor integrated circuit for reducing the adverse effect of parasitic capacitance generated on a semiconductor substrate.
【０００２】[0002]
【従来の技術】例えば、ＣＤプレーヤーや赤外線通信機
においては、レザー光や赤外線等を受光する受光素子が
備えられている。一般に、受光素子としてフォトダイオ
ードが使用され、受光された光の強度に応じて出力電流
が発生する。この受光素子からは電流モードで出力信号
が発生するが、受光素子の後段の信号処理する回路は電
圧モードで動作する。従って、受光素子と信号処理回路
との間には受光素子の出力電流を電圧変換する電流電圧
変換回路が必要となる。図２は従来の電流電圧変換回路
を示す。2. Description of the Related Art For example, a CD player or an infrared communication device is provided with a light receiving element for receiving laser light, infrared light or the like. Generally, a photodiode is used as a light receiving element, and an output current is generated according to the intensity of received light. An output signal is generated from this light receiving element in a current mode, but a signal processing circuit at a subsequent stage of the light receiving element operates in a voltage mode. Therefore, a current-to-voltage conversion circuit for converting the output current of the light receiving element into a voltage is required between the light receiving element and the signal processing circuit. FIG. 2 shows a conventional current-voltage conversion circuit.
【０００３】図２の増幅器１は、受光素子２からの出力
信号がない時、平衡状態にある。つまり、増幅器１の出
力信号が帰還抵抗３を介して増幅器１の負入力端子に帰
還される。その際、増幅器１の出力信号は、増幅器１の
負入力端子の入力電圧が正入力端子の入力電圧に等しく
なるように調整される。帰還抵抗３に流れる電流をＩ
１、出力電圧をＶ１、帰還抵抗３の抵抗値をＲ１とする
と、Ｖ１＝Ｒ１×Ｉ１となる。この状態にて、受光素子
に例えば赤外線が照射され、受光素子２から出力電流Ｉ
２が発生したとすると、出力電流Ｉ２は帰還抵抗３に流
れるので、出力電圧Ｖ２は、Ｖ２＝Ｒ１×（Ｉ１＋Ｉ
２）となる。従って、受光素子の出力電流は帰還抵抗３
で電流電圧変換されたことになる。The amplifier 1 shown in FIG. 2 is in a balanced state when there is no output signal from the light receiving element 2. That is, the output signal of the amplifier 1 is fed back to the negative input terminal of the amplifier 1 via the feedback resistor 3. At this time, the output signal of the amplifier 1 is adjusted so that the input voltage of the negative input terminal of the amplifier 1 becomes equal to the input voltage of the positive input terminal. The current flowing through the feedback resistor 3 is represented by I
Assuming that 1, the output voltage is V1, and the resistance value of the feedback resistor 3 is R1, V1 = R1 × I1. In this state, the light receiving element is irradiated with, for example, infrared light, and the output current I
2 occurs, the output current I2 flows through the feedback resistor 3, so that the output voltage V2 is V2 = R1 × (I1 + I
2). Therefore, the output current of the light receiving element is equal to the feedback resistance 3
This means that current-voltage conversion has been performed.
【０００４】[0004]
【発明が解決しようとする課題】近年では、少なくとも
増幅器１及び受光素子２が同一の半導体基板上に集積化
される。しかし、このような半導体基板上では、受光素
子１となるフォトダイオードのカソードと、サブストレ
ートとの間に、図２の如く寄生容量Ｃが発生する。寄生
容量Ｃの大きさは電圧電流変換回路の特性に影響を与え
る大きさであって、無視することはできなかった。ま
た、従来では、増幅器１の出力電圧にノイズが発生する
ことを防止するため、ノイズ低減用の抵抗４が接続され
る。その結果、寄生容量Ｃと抵抗４との時定数により電
流電圧変換回路の周波数特性が悪化するという問題があ
った。In recent years, at least the amplifier 1 and the light receiving element 2 are integrated on the same semiconductor substrate. However, on such a semiconductor substrate, a parasitic capacitance C is generated between the cathode of the photodiode serving as the light receiving element 1 and the substrate as shown in FIG. The magnitude of the parasitic capacitance C affects the characteristics of the voltage-current conversion circuit and cannot be ignored. Conventionally, a noise reducing resistor 4 is connected to prevent noise from occurring in the output voltage of the amplifier 1. As a result, there is a problem that the time constant of the parasitic capacitance C and the resistance 4 deteriorates the frequency characteristics of the current-voltage conversion circuit.
【０００５】[0005]
【課題を解決するための手段】本発明に依れば、受光素
子と、受光素子の出力信号を電流電圧変換する電流電圧
変換回路とを同一半導体基板上に集積化された受光用半
導体集積回路において、前記受光素子は複数の領域に分
割されると共に、電流電圧変換回路は複数の受光素子に
対応して複数の変換部を備えて成り、さらに、前記変換
部の出力信号を加算する加算回路を備えることを特徴と
する。According to the present invention, a light-receiving semiconductor integrated circuit in which a light-receiving element and a current-to-voltage conversion circuit for converting the output signal of the light-receiving element into a current-voltage circuit are integrated on the same semiconductor substrate. , The light receiving element is divided into a plurality of regions, the current-voltage conversion circuit includes a plurality of conversion units corresponding to the plurality of light receiving elements, and further, an addition circuit for adding an output signal of the conversion unit It is characterized by having.
【０００６】特に、前記変換部は、基準電圧が印加され
る正入力端子、前記受光素子が接続される負入力端子、
及び出力電圧が発生する出力端子を有する増幅器と、前
記負入力端子及び出力端子間に接続された帰還抵抗とに
より構成されることを特徴とする。In particular, the converter includes a positive input terminal to which a reference voltage is applied, a negative input terminal to which the light receiving element is connected,
And an amplifier having an output terminal for generating an output voltage, and a feedback resistor connected between the negative input terminal and the output terminal.
【０００７】本発明に依れば、受光素子を複数個に分割
したことにより、寄生容量が小さくなり、出力周波数特
性が改善される。According to the present invention, by dividing the light receiving element into a plurality, the parasitic capacitance is reduced and the output frequency characteristic is improved.
【０００８】[0008]
【発明の実施の形態】図１は本発明の実施の形態を示す
図であり、５は例えば３つに分割された受光部５ａ〜５
ｃから成る受光素子、６乃至８は受光素子５ａ〜５ｃの
出力信号をそれぞれ電流電圧変換する電流電圧変換回
路、９は電流電圧変換回路６乃至８の出力電圧を加算す
る加算回路である。FIG. 1 is a view showing an embodiment of the present invention. Reference numeral 5 denotes, for example, three divided light receiving portions 5a to 5a.
The light receiving elements 6 to 8 are current-to-voltage conversion circuits for converting the output signals of the light receiving elements 5a to 5c into current-to-voltage conversions, respectively.
【０００９】図１において、受光素子５ａ〜５ｃに光が
照射されていないと、受光素子５ａ〜５ｃから出力信号
が発生しない。この状態では、電流電圧変換回路６乃至
８は平衡状態になり、無信号時に対応する所定レベルの
出力電圧が電流電圧変換回路６乃至８から発生する。In FIG. 1, if the light receiving elements 5a to 5c are not irradiated with light, no output signal is generated from the light receiving elements 5a to 5c. In this state, the current-voltage conversion circuits 6 to 8 are in a balanced state, and output voltages of a predetermined level corresponding to the absence of a signal are generated from the current-voltage conversion circuits 6 to 8.
【００１０】例えば、電流電圧変換回路６では、増幅器
６ａの出力信号が帰還抵抗６ｂを介して増幅器６ａの負
入力端子に帰還される。その際、増幅器６ａの出力信号
は、増幅器６ａの負入力端子の入力電圧が正入力端子の
入力電圧に等しくなるように調整される。無信号時帰還
抵抗６ｂには帰還信号しか流れず、受光素子５ａの出力
信号は流れない。無信号時、帰還抵抗６ｂに流れる電流
をＩａ１、出力電圧をＶａ１、帰還抵抗６ｂの抵抗値を
Ｒａとすると、Ｖａ１＝Ｒａ×Ｉａ１となる。For example, in the current-voltage conversion circuit 6, the output signal of the amplifier 6a is fed back to the negative input terminal of the amplifier 6a via the feedback resistor 6b. At this time, the output signal of the amplifier 6a is adjusted so that the input voltage of the negative input terminal of the amplifier 6a becomes equal to the input voltage of the positive input terminal. Only the feedback signal flows through the feedback resistor 6b when there is no signal, and the output signal of the light receiving element 5a does not flow. When there is no signal, if the current flowing through the feedback resistor 6b is Ia1, the output voltage is Va1, and the resistance value of the feedback resistor 6b is Ra, then Va1 = Ra × Ia1.
【００１１】無信号時には、電流電圧変換回路７及び８
においても電流電圧変換回路６と同様の動作が行われ
る。無信号時、他の受光素子５ｂ及び５ｃからも出力信
号が発生しないので、電流電圧変換回路７及び８の出力
電圧は無信号時に対応する所定レベルの電圧が発生す
る。つまり、増幅器７ａ及び８ａの帰還信号をそれぞれ
帰還抵抗７ｂ及び８ｂで電圧変換した出力電圧Ｖｂ１及
びＶｃ１が発生する。When there is no signal, the current-voltage conversion circuits 7 and 8
The same operation as in the current-voltage conversion circuit 6 is performed in When there is no signal, no output signal is generated from the other light receiving elements 5b and 5c, so that the output voltage of the current / voltage conversion circuits 7 and 8 has a predetermined level corresponding to the time when there is no signal. That is, output voltages Vb1 and Vc1 are generated by converting the feedback signals of the amplifiers 7a and 8a by the feedback resistors 7b and 8b, respectively.
【００１２】電流電圧変換回路６乃至８の出力電圧Ｖａ
１乃至Ｖｃ１は、加算回路９で加算され、出力電圧Ｖｏ
ｕｔとして出力される。The output voltage Va of the current-voltage conversion circuits 6 to 8
1 to Vc1 are added by the adding circuit 9, and the output voltage Vo
ut is output.
【００１３】ここで、受光素子５ａ乃至５ｃに例えば赤
外線が照射されると、各々の受光素子５ａ乃至５ｃから
出力信号が発生する。それぞれの受光素子５ａ乃至５ｃ
からの出力電流は帰還抵抗６ｂ乃至８ｂで電圧変換され
る。例えば、受光素子５ａから出力電流Ｉａ２が発生し
たとすると、出力電流Ｉａ２は帰還抵抗６ｂに流れるの
で、出力電圧Ｖａ２は、Ｖａ２＝Ｒａ×（Ｉａ１＋Ｉａ
２）となる。Here, when the light receiving elements 5a to 5c are irradiated with, for example, infrared rays, output signals are generated from the respective light receiving elements 5a to 5c. Each light receiving element 5a to 5c
Is converted into a voltage by the feedback resistors 6b to 8b. For example, if an output current Ia2 is generated from the light receiving element 5a, the output current Ia2 flows through the feedback resistor 6b, so that the output voltage Va2 is Va2 = Ra × (Ia1 + Ia
2).
【００１４】また、他の受光素子５ｂ及び５ｃでも、出
力電流が発生すると、電流電圧変換回路６の出力電圧と
同様にして、電流電圧変換回路７及び８から電圧変換さ
れた出力電圧Ｖｂ２及びＶｃ２が発生する。When an output current is generated in the other light receiving elements 5b and 5c, the output voltages Vb2 and Vc2 converted from the current / voltage conversion circuits 7 and 8 are converted in the same manner as the output voltage of the current / voltage conversion circuit 6. Occurs.
【００１５】それぞれの電流電圧発生回路６乃至８から
の出力電圧Ｖａ２乃至Ｖｃ２は加算された後、出力電圧
Ｖｏｕｔとして出力される。The output voltages Va2 to Vc2 from the current voltage generators 6 to 8 are added and output as an output voltage Vout.
【００１６】ところで、本発明の回路をＩＣ化した場
合、受光素子や電流電圧変換回路、加算回路のパターン
は、例えば、図３のように形成される。本発明の受光素
子の全体の面積は、従来の受光素子の面積に略等しい大
きさに設定される。従って、本発明による受光素子の分
割は、従来の受光素子を複数個に分割したのであり、新
たに受光素子領域を付加したものではない。By the way, when the circuit of the present invention is formed into an IC, the patterns of the light receiving element, the current-voltage conversion circuit, and the addition circuit are formed as shown in FIG. 3, for example. The entire area of the light receiving element of the present invention is set to a size substantially equal to the area of the conventional light receiving element. Therefore, the division of the light receiving element according to the present invention is obtained by dividing the conventional light receiving element into a plurality, and does not add a new light receiving element region.
【００１７】受光素子に生成される寄生容量の大きさ
は、受光素子の面積に比例される。各々の受光素子の面
積は従来に比べ小さくなるので、本発明の受光素子での
寄生容量は小さくなる。その為、ノイズ低減用の抵抗と
寄生容量とによる時定数も小さくなり、各々の電流電圧
変換回路６乃至８の出力の周波数特性が改善される。従
って、加算回路９は入力信号を単に加算するだけなの
で、加算回路９の出力の周波数特性も改善される。尚、
前記時定数は遮断周波数を定め、遮断周波数は寄生容量
が大きくなるほど低くなる。The magnitude of the parasitic capacitance generated in the light receiving element is proportional to the area of the light receiving element. Since the area of each light receiving element is smaller than that of the related art, the parasitic capacitance of the light receiving element of the present invention is smaller. Therefore, the time constant due to the noise reducing resistor and the parasitic capacitance is also reduced, and the frequency characteristics of the outputs of the current-to-voltage conversion circuits 6 to 8 are improved. Accordingly, since the addition circuit 9 simply adds the input signals, the frequency characteristic of the output of the addition circuit 9 is also improved. still,
The time constant determines the cutoff frequency, and the cutoff frequency decreases as the parasitic capacitance increases.
【００１８】[0018]
【発明の効果】本発明に依れば、受光素子を分割したの
で、寄生容量が小さくなり、電流電圧発生回路の周波数
特性を改善することができる。According to the present invention, since the light receiving element is divided, the parasitic capacitance is reduced, and the frequency characteristics of the current / voltage generating circuit can be improved.
【図１】本発明の実施の形態を示す回路図である。FIG. 1 is a circuit diagram showing an embodiment of the present invention.
【図２】従来例を示す回路図である。FIG. 2 is a circuit diagram showing a conventional example.
【図３】本発明の回路図を半導体基板上に配置したパタ
ーンを示す図である。FIG. 3 is a diagram showing a pattern in which the circuit diagram of the present invention is arranged on a semiconductor substrate.
５ａ〜５ｃ 受光素子 ６〜８ 電流電圧変換回路 ９ 加算回路 5a-5c Light receiving element 6-8 Current-voltage conversion circuit 9 Addition circuit
Claims (2)
電圧変換する電流電圧変換回路とを同一半導体基板上に
集積化された受光用半導体集積回路において、前記受光
素子は複数の領域に分割されると共に、電流電圧変換回
路は複数の受光素子に対応して複数の変換部を備えて成
り、さらに、前記変換部の出力信号を加算する加算回路
を備えることを特徴とする受光用半導体集積回路。1. A light-receiving semiconductor integrated circuit in which a light-receiving element and a current-to-voltage conversion circuit for current-to-voltage conversion of an output signal of the light-receiving element are integrated on the same semiconductor substrate, wherein the light-receiving element is divided into a plurality of regions. And a current-voltage conversion circuit including a plurality of conversion units corresponding to the plurality of light-receiving elements, and further including an addition circuit for adding an output signal of the conversion unit. circuit.
入力端子、前記受光素子が接続される負入力端子、及び
出力電圧が発生する出力端子を有する増幅器と、前記負
入力端子及び出力端子間に接続された帰還抵抗とにより
構成されることを特徴とする請求項1記載の受光用半導
体集積回路。2. An amplifier having a positive input terminal to which a reference voltage is applied, a negative input terminal to which the light receiving element is connected, and an output terminal to generate an output voltage, the conversion unit comprising: a negative input terminal; 2. The light receiving semiconductor integrated circuit according to claim 1, comprising a feedback resistor connected between terminals.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10147399A JPH11340925A (en) | 1998-05-28 | 1998-05-28 | Semiconductor integrated circuit for receiving light |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10147399A JPH11340925A (en) | 1998-05-28 | 1998-05-28 | Semiconductor integrated circuit for receiving light |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH11340925A true JPH11340925A (en) | 1999-12-10 |
Family
ID=15429415
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10147399A Pending JPH11340925A (en) | 1998-05-28 | 1998-05-28 | Semiconductor integrated circuit for receiving light |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH11340925A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005531129A (en) * | 2002-03-22 | 2005-10-13 | メレキシス ゲーエムベーハー | Optical fiber receiver with increasing bandwidth |
| JP2007318645A (en) * | 2006-05-29 | 2007-12-06 | Sanyo Electric Co Ltd | Subtraction circuit |
| JP2008153930A (en) * | 2006-12-18 | 2008-07-03 | Taiko Denki Co Ltd | Light receiving device for spatial optical communication |
| JP2014044841A (en) * | 2012-08-27 | 2014-03-13 | West Japan Railway Co | Arc detection device for dc high-voltage circuit breaker |
-
1998
- 1998-05-28 JP JP10147399A patent/JPH11340925A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005531129A (en) * | 2002-03-22 | 2005-10-13 | メレキシス ゲーエムベーハー | Optical fiber receiver with increasing bandwidth |
| JP2007318645A (en) * | 2006-05-29 | 2007-12-06 | Sanyo Electric Co Ltd | Subtraction circuit |
| JP2008153930A (en) * | 2006-12-18 | 2008-07-03 | Taiko Denki Co Ltd | Light receiving device for spatial optical communication |
| JP2014044841A (en) * | 2012-08-27 | 2014-03-13 | West Japan Railway Co | Arc detection device for dc high-voltage circuit breaker |
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