JPH0127311Y2 - - Google Patents
Info
- Publication number
- JPH0127311Y2 JPH0127311Y2 JP1982173703U JP17370382U JPH0127311Y2 JP H0127311 Y2 JPH0127311 Y2 JP H0127311Y2 JP 1982173703 U JP1982173703 U JP 1982173703U JP 17370382 U JP17370382 U JP 17370382U JP H0127311 Y2 JPH0127311 Y2 JP H0127311Y2
- Authority
- JP
- Japan
- Prior art keywords
- loop circuit
- current loop
- light emitting
- current
- transmission line
- 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.)
- Expired
Links
- 230000005540 biological transmission Effects 0.000 claims description 27
- 230000000295 complement effect Effects 0.000 claims description 2
- 230000005669 field effect Effects 0.000 claims 1
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 1
Description
【考案の詳細な説明】
産業上の利用分野
本考案はフオトカプラーを用いた情報伝送回路
に採用されて有用なカレントループ回路に関す
る。[Detailed Description of the Invention] Industrial Application Field The present invention relates to a current loop circuit useful for use in an information transmission circuit using a photocoupler.
従来技術
情報伝送回路に於ては、送信側と受信側とを電
気的に完全に分離した状態として両者が互に干渉
する事のないような構成を採る為に発光素子と受
光素子とから成るフオトカプラーが用いられてい
る。そしてそのフオトカプラーの発光素子を駆動
する為の回路として第１図に示すカレントループ
回路が多用されている。 Prior Art Information transmission circuits consist of a light-emitting element and a light-receiving element in order to completely electrically separate the transmitting side and the receiving side so that they do not interfere with each other. A photocoupler is used. A current loop circuit shown in FIG. 1 is often used as a circuit for driving the light emitting element of the photocoupler.
この第１図に於て、Q1，Q2は伝送すべき情報
DTに依つて相補的にON，OFF動作するスイツ
チングトランジスタで、その各コレクタは伝送抵
抗R1，R2及び伝送路T1，T2を介してフオトカプ
ラーPCを構成している発光ダイオードLEDに連
つている。BDは該発光ダイオードLEDに逆並列
に接続されたバイパスダイオード、PTは発光ダ
イオードLEDと共にフオトカプラーを構成して
いるフオトトランジスタで、このトランジスタ
PTのコレクタから受信情報DRが得られる。 In this Figure 1, Q 1 and Q 2 are the information to be transmitted.
A switching transistor that turns ON and OFF in a complementary manner depending on the DT, each collector of which is a light emitting diode LED that constitutes a photocoupler PC via transmission resistors R 1 and R 2 and transmission lines T 1 and T 2 . It is connected to BD is a bypass diode connected in antiparallel to the light emitting diode LED, and PT is a phototransistor that forms a photocoupler together with the light emitting diode LED.
Reception information DR is obtained from the PT collector.
斯る構成のカレントループ回路の場合、伝送路
T1，T2の距離が長くなると、ノイズ等の影響を
多く受け、信頼性が低下する。 In the case of a current loop circuit with such a configuration, the transmission line
As the distance between T 1 and T 2 becomes longer, the reliability is lowered due to the influence of noise and the like.
この欠点を改良したのが第２図に示した抵抗分
割型のカレントループ回路である。この回路は伝
送路T1，T2とフオトカプラーPCとの間に直列抵
抗R3，R4及び並列低抗R5から成るブリツジRBを
設けたもので、ノイズ等の影響を受けないように
伝送路T1，T2に充分の電流を流し、発光ダイオ
ードLEDにはそのうちの一部を流して残りの電
流は並列抵抗R5に流すようにしている。 The resistance division type current loop circuit shown in FIG. 2 has improved this drawback. In this circuit, a bridge RB consisting of series resistors R 3 , R 4 and parallel low resistance R 5 is installed between the transmission lines T 1 , T 2 and the photocoupler PC to avoid being affected by noise etc. A sufficient amount of current is passed through the transmission lines T 1 and T 2 , a portion of which is passed through the light emitting diode LED, and the remaining current is passed through the parallel resistor R 5 .
この改良されたカレントループ回路に依ると、
ノイズ等に対しては強くなるが、伝送路T1，T2
の線路抵抗が変化した場合、発光ダイオード
LEDに流れる電流も変化するのでその都度抵抗
値の設定が必要となる。 According to this improved current loop circuit,
Although it is resistant to noise etc., the transmission lines T 1 and T 2
If the line resistance changes, the light emitting diode
Since the current flowing through the LED also changes, it is necessary to set the resistance value each time.
考案の目的
本考案は上述の諸問題を改善すべく為されたも
のであつて、ノイズ耐性は強く、且つ伝送路の線
路抵抗が変化しても調整不要のカレントループ回
路を提供する事を目的としている。 Purpose of the invention The present invention was made to improve the above-mentioned problems, and the purpose is to provide a current loop circuit that has strong noise resistance and does not require adjustment even if the line resistance of the transmission line changes. It is said that
考案の構成
本考案は、フオトカプラーを構成している発光
ダイオードの両端を定電流素子を介して伝送路に
結合したところに主たる特徴を有する。 Structure of the invention The main feature of the invention is that both ends of a light emitting diode constituting a photocoupler are coupled to a transmission line via a constant current element.
実施例
第３図は本考案カレントループ回路を示してお
り、第１図、第２図と同様にQ1，Q2はスイツチ
ンブトランジスタ、T1，T2は伝送路、PCはフオ
トカプラーである。CCは伝送路T1，T2とフオト
カプラーPCを構成している発光ダイオードLED
との間に設けられた定電流回路で、この定電流回
路CCは、伝送路T1と発光ダイオードLEDのアノ
ードとの間に挿入接続された第１のジヤンクシヨ
ン型FET，JF1と、伝送路T2と発光ダイオード
LEDのカソードとの間に挿入接続された第２の
ジヤンクシヨン型FET，JE2と、これ等の両
FETJE1，JE2の各伝送路T1，T2側に並列に設け
られた分流抵抗R6と、から構成されている。更
に詳しく説明するならば、各FET，JE1，JE2の
各ゲートＧはソースＳに直結されており、そのソ
ースＳは夫々伝送路T1，T2側に接続され、また
ドレインＤは夫々発光ダイオードLEDに連つて
いる。 Embodiment Figure 3 shows the current loop circuit of the present invention, in which Q 1 and Q 2 are switch transistors, T 1 and T 2 are transmission lines, and PC is a photocoupler, as in Figures 1 and 2. be. CC is the light emitting diode LED that composes the transmission lines T 1 and T 2 and the photocoupler PC
This constant current circuit CC is a constant current circuit provided between the transmission line T 1 and the first junction FET, JF 1 , which is inserted and connected between the transmission line T 1 and the anode of the light emitting diode LED, and the transmission line T 2 and light emitting diode
A second junction type FET, JE 2 , inserted and connected between the cathode of the LED, and both of these
It consists of a shunt resistor R 6 provided in parallel on the transmission lines T 1 and T 2 sides of FETJE 1 and JE 2 . To explain in more detail, each gate G of each FET, JE 1 and JE 2 is directly connected to a source S, the source S is connected to the transmission line T 1 and T 2 side, respectively, and the drain D is connected to the respective transmission line T 1 and T 2 side. It is connected to a light emitting diode LED.
このようにジヤンクシヨン型FET，JE1，JE2
のソース・ゲート間を短絡した状態でソース・ド
レイン間に該FET，JE1，JE2の閾値電圧以上の
電圧を印加すると定電流特性を示すので、伝送路
T1，T2にダイオードLEDに流す電流に対して余
裕を持たした電流を流しておく事に依つて、伝送
路T1，T2の経路が長くなつて線路抵抗が増大し
ても発光ダイオードLEDには常に定電流が流れ、
それ以外の電流は分流抵抗を流れる事となる。 In this way, junction type FET, JE 1 , JE 2
If a voltage higher than the threshold voltage of the FET, JE 1 , and JE 2 is applied between the source and drain with the source and gate short-circuited, constant current characteristics will be exhibited, so the transmission line
By allowing current to flow through T 1 and T 2 with a margin for the current flowing through the diode LED, even if the transmission paths T 1 and T 2 become longer and the line resistance increases, the light emitting diode A constant current always flows through the LED,
Other currents will flow through the shunt resistor.
考案の効果
本考案は以上の説明から明らかな如く、発光素
子は定電流素子を介して伝送路に接続されている
ので、伝送路の線路抵抗が変化しても発光素子に
は常電流しか流れず、伝送路が変る都度回路定数
を調整する必要がなく、汎用性の高いカレントル
ープ回路を得る事が出来る。 Effects of the invention As is clear from the above explanation, the light emitting element is connected to the transmission line via the constant current element, so even if the line resistance of the transmission line changes, only a constant current flows through the light emitting element. First, there is no need to adjust circuit constants every time the transmission path changes, and a highly versatile current loop circuit can be obtained.
第１図、第２図は夫々従来回路を示す電気回路
図、第３図は本考案カレントループ回路の電気回
路図であつて
Ｑはスイツチングトランジスタ、Ｔは伝送路、
PTはフオトカプラ、CCは定電流回路、JFはジ
ヤンクシヨンFET、を夫々示している。
1 and 2 are electric circuit diagrams showing conventional circuits, and FIG. 3 is an electric circuit diagram of the current loop circuit of the present invention, where Q is a switching transistor, T is a transmission line,
PT indicates a photocoupler, CC indicates a constant current circuit, and JF indicates a junction FET.
Claims (1)
動作する一対のスイツチング素子と、該各素子
に伝送路を経由して両端が接続された発光素子
と、から成るカレントループ回路に於て、該発
光素子の両端は夫々定電流素子を介して伝送路
に接続されると共に、該定電流素子の各他端間
に分流抵抗を連結した事を特徴とするカレント
ループ回路。 (2) 上記定電流素子はゲートを伝送路側に直結し
た電界効果型トランジスタである事を特徴とし
た実用新案登録請求の範囲第１項記載のカレン
トループ回路。[Scope of utility model registration claims] (1) Turning on and off in a complementary manner to each other in response to a transmission signal
In a current loop circuit consisting of a pair of operating switching elements and a light emitting element whose both ends are connected to each element via a transmission line, both ends of the light emitting element transmit data via constant current elements. 1. A current loop circuit, characterized in that the current loop circuit is connected to a current loop circuit, and a shunt resistor is connected between each other end of the constant current element. (2) The current loop circuit according to claim 1, wherein the constant current element is a field effect transistor whose gate is directly connected to the transmission line side.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1982173703U JPS5978756U (en) | 1982-11-16 | 1982-11-16 | current loop circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1982173703U JPS5978756U (en) | 1982-11-16 | 1982-11-16 | current loop circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5978756U JPS5978756U (en) | 1984-05-28 |
| JPH0127311Y2 true JPH0127311Y2 (en) | 1989-08-15 |
Family
ID=30378340
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1982173703U Granted JPS5978756U (en) | 1982-11-16 | 1982-11-16 | current loop circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5978756U (en) |
-
1982
- 1982-11-16 JP JP1982173703U patent/JPS5978756U/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5978756U (en) | 1984-05-28 |
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