JP2520379B2 - Balanced constant current circuit - Google Patents
Balanced constant current circuitInfo
- Publication number
- JP2520379B2 JP2520379B2 JP62080193A JP8019387A JP2520379B2 JP 2520379 B2 JP2520379 B2 JP 2520379B2 JP 62080193 A JP62080193 A JP 62080193A JP 8019387 A JP8019387 A JP 8019387A JP 2520379 B2 JP2520379 B2 JP 2520379B2
- Authority
- JP
- Japan
- Prior art keywords
- amplifier
- output
- input
- constant current
- voltage
- 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 - Lifetime
Links
Description
【発明の詳細な説明】 （ａ）発明の技術分野 この発明は、平衡回線で構成する通信線路の導体抵抗
を測定する場合に、この導体抵抗に測定用の定電流をフ
ローティング状態で供給することができる平衡型定電流
回路についてのものである。Description: (a) Technical Field of the Invention The present invention, when measuring the conductor resistance of a communication line constituted by a balanced line, supplies a constant current for measurement to the conductor resistance in a floating state. This is for a balanced constant current circuit that can
（ｂ）従来技術と問題点 平衡回線で構成されている通信回線の導体抵抗を測定
する場合には、この導体抵抗に定電流を流し、導体抵抗
の電圧降下から導体抵抗の抵抗値を算出する。(B) Prior art and problems When measuring the conductor resistance of a communication line composed of a balanced line, a constant current is applied to this conductor resistance and the resistance value of the conductor resistance is calculated from the voltage drop of the conductor resistance. .
この場合に、定電流を供給する定電流源は、接地に対
してフローティングの状態になければならない。In this case, the constant current source that supplies the constant current must be floating with respect to ground.
定電流回路をフローティングさせる従来技術には、DC
−DCコンバータを使用する方法がある。The conventional technology for floating the constant current circuit is DC
-There is a method of using a DC converter.
しかし、DC−DCコンバータを使用する方法は、DC−DC
コンバータから発生するスイッチング状のノイズが通信
回線に重畳するという問題がある。However, the method of using the DC-DC converter is DC-DC.
There is a problem that switching noise generated from the converter is superimposed on the communication line.
（ｃ）発明の目的 この発明は、平衡回線で構成されている通信回線の導
体抵抗を測定する場合に、DC−DCコンバータを使用しな
いで、接地に対してフローティング状態になる定電流回
路の提供を目的とする。(C) Object of the Invention The present invention provides a constant current circuit that is in a floating state with respect to ground without using a DC-DC converter when measuring the conductor resistance of a communication line configured by a balanced line. With the goal.
（ｄ）発明の実施例 まず、この発明による実施例の構成図を第１図に示
す。(D) Embodiment of the Invention First, FIG. 1 shows a block diagram of an embodiment according to the present invention.
第１図の１と２は定電流回路、３は基準電源、４は加
算器、５は導体抵抗である。1 and 2 in FIG. 1 are constant current circuits, 3 is a reference power source, 4 is an adder, and 5 is a conductor resistance.
導体抵抗５は平衡回線で構成されている通信回線の導
体抵抗を等価的に示したものである。導体抵抗５の両端
の電圧をVeとする。The conductor resistance 5 is equivalent to the conductor resistance of the communication line constituted by the balanced line. The voltage across the conductor resistance 5 is Ve.
定電流回路１は、増幅器1a、負荷抵抗1b、増幅器1cか
ら構成される。The constant current circuit 1 includes an amplifier 1a, a load resistor 1b, and an amplifier 1c.
増幅器1aは入出力が同相の増幅器であり、増幅器1cも
入出力が同相の増幅器である。The input / output of the amplifier 1a is an in-phase amplifier, and the input / output of the amplifier 1c is also an in-phase amplifier.
負荷抵抗1bは増幅器1aの出力と導体抵抗５の端部5aの
間に接続される。The load resistor 1b is connected between the output of the amplifier 1a and the end 5a of the conductor resistor 5.
増幅器1cは、入力側を導体抵抗５の端部5aに接続し、
出力側を増幅器1aの入力に接続する。The amplifier 1c has the input side connected to the end 5a of the conductor resistor 5,
The output side is connected to the input of the amplifier 1a.
基準電源３は、出力電圧Voを増幅器1aの入力に接続す
る。The reference power supply 3 connects the output voltage Vo to the input of the amplifier 1a.
定電流回路２は、増幅器2a、負荷抵抗2b、増幅器2cか
ら構成される。定電流回路２は、定電流回路１と同じ部
品で構成することができる。The constant current circuit 2 includes an amplifier 2a, a load resistor 2b, and an amplifier 2c. The constant current circuit 2 can be composed of the same parts as the constant current circuit 1.
増幅器2aは入出力が同相の増幅器であり、増幅器2cも
入出力が同相の増幅器である。The input / output of the amplifier 2a is an in-phase amplifier, and the input / output of the amplifier 2c is also an in-phase amplifier.
負荷抵抗2bは増幅器2aの出力と導体抵抗５の端部5bの
間に接続される。The load resistor 2b is connected between the output of the amplifier 2a and the end 5b of the conductor resistor 5.
増幅器2cは、入力側を導体抵抗５の端部5bに接続し、
出力側を増幅器2aの入力に接続する。The amplifier 2c has the input side connected to the end 5b of the conductor resistor 5,
The output side is connected to the input of the amplifier 2a.
加算器４は、加算用の抵抗4a、4b、4cと増幅器4dから
構成される。The adder 4 is composed of resistors 4a, 4b, 4c for addition and an amplifier 4d.
増幅器4dは、入出力が逆相の増幅器である。 The amplifier 4d is an amplifier whose input and output have opposite phases.
加算器４は、基準電源３の出力電圧Voと、導体抵抗５
の端部5aの電圧＋ΔVeaと、導体抵抗５の端部5bの電圧
−ΔVebとを加算し、加算出力を増幅器4dで反転する。The adder 4 outputs the output voltage Vo of the reference power source 3 and the conductor resistance 5
The voltage + ΔVea at the end portion 5a and the voltage −ΔVeb at the end portion 5b of the conductor resistance 5 are added, and the addition output is inverted by the amplifier 4d.
加算器４の出力は、増幅器2aの入力に接続される。 The output of the adder 4 is connected to the input of the amplifier 2a.
次に、第１図の作用を説明する。 Next, the operation of FIG. 1 will be described.
定電流回路１からの定電流は負荷抵抗1b、導体抵抗５
及び負荷抵抗2bを通り、定電流回路２で吸収される。The constant current from the constant current circuit 1 is load resistance 1b, conductor resistance 5
And the load resistance 2b, and is absorbed by the constant current circuit 2.
導体抵抗５の抵抗値は、例えば10kΩ、1kΩ、100Ωな
どの場合があり、負荷抵抗1b＝100Ω、負荷抵抗2b＝100
Ωなどにする。The resistance value of the conductor resistance 5 may be, for example, 10 kΩ, 1 kΩ, 100 Ω, etc., and the load resistance 1b = 100 Ω and the load resistance 2b = 100.
Ω, etc.
基準電源３の電圧を1Vとし、増幅器1aの利得を２、増
幅器1cの利得を１とすると、負荷抵抗1bの両端には1Vの
電圧が現れる。Assuming that the voltage of the reference power source 3 is 1V, the gain of the amplifier 1a is 2, and the gain of the amplifier 1c is 1, a voltage of 1V appears across the load resistor 1b.
同じように、負荷抵抗2bの両端にも1Vが現れる。この
場合、基準電源３を接地しているので、負荷抵抗1bと負
荷抵抗2bの電圧は極性が反転する。Similarly, 1V appears across the load resistor 2b. In this case, since the reference power source 3 is grounded, the polarities of the voltages of the load resistance 1b and the load resistance 2b are reversed.
前述のとおり、加算器４は基準電源３の出力電圧Vo、
導体抵抗５の端部5aの電圧＋ΔVea及び導体抵抗５の端
部5bの電圧−ΔVebを加算する。As mentioned above, the adder 4 outputs the output voltage Vo of the reference power source 3,
The voltage + ΔVea at the end 5a of the conductor resistance 5 and the voltage −ΔVeb at the end 5b of the conductor resistance 5 are added.
電圧＋ΔVeaと電圧−ΔVebが等しければ、電圧＋ΔVe
aと電圧−ΔVebで相殺され、加算器４の出力は、基準電
圧Voの反転電圧−Voだけが増幅器2aの入力に加えられ
る。この結果、導体抵抗５の端部5aは＋（1/2）Veの電
圧になり、導体抵抗５の他端5bは−（1/2）Veの電圧に
なる。If voltage + ΔVea and voltage −ΔVeb are equal, voltage + ΔVe
The value a and the voltage −ΔVeb cancel each other out, and the output of the adder 4 is only the inverted voltage −Vo of the reference voltage Vo applied to the input of the amplifier 2a. As a result, the end 5a of the conductor resistor 5 has a voltage of + (1/2) Ve, and the other end 5b of the conductor resistor 5 has a voltage of-(1/2) Ve.
電圧＋ΔVeaと電圧−ΔVebが等しくないときは、差の
電圧の反転電圧が−Voとともに増幅器2aの入力に加えら
れ、定電流回路２の負荷抵抗2bの両端の電圧が変化し、
導体抵抗５の端部5aが＋（1/2）Veの電圧になり、導体
抵抗５の端部5bが−（1/2）Veの電圧になるように働
く。When the voltage + ΔVea is not equal to the voltage −ΔVeb, the inversion voltage of the difference voltage is applied to the input of the amplifier 2a together with −Vo, and the voltage across the load resistor 2b of the constant current circuit 2 changes.
The end 5a of the conductor resistor 5 is at a voltage of + (1/2) Ve, and the end 5b of the conductor resistor 5 is at a voltage of-(1/2) Ve.
すなわち、第１図の回路は、基準電源３、加算器４を
使い、負荷抵抗1b、負荷抵抗2bの電圧を調節し、絶えず
導体抵抗５の両端の電圧が極性が反対で同じ電圧になる
ようにするものである。That is, the circuit of FIG. 1 uses the reference power supply 3 and the adder 4 to adjust the voltages of the load resistance 1b and the load resistance 2b so that the voltage across the conductor resistance 5 is always the same with opposite polarities. It is something to do.
（ｅ）発明の効果 この発明によれば、基準電源、加算器及び２個の定電
流回路を使用し、加算器出力で導体抵抗に供給する電圧
を調整しているので、接地に対してフローティングした
定電流を導体抵抗に供給することができる。(E) Effect of the Invention According to the present invention, the reference power supply, the adder, and the two constant current circuits are used, and the voltage supplied to the conductor resistance is adjusted at the output of the adder. The constant current can be supplied to the conductor resistance.
第１図はこの発明による実施例の構成図。 １……定電流回路、1a……増幅器、1b……負荷抵抗、1c
……増幅器、 ２……定電流回路、2a……増幅器、2b……負荷抵抗、2c
……増幅器、 ３……基準電源、４……加算器、 ５……導体抵抗。FIG. 1 is a block diagram of an embodiment according to the present invention. 1 ... Constant current circuit, 1a ... Amplifier, 1b ... Load resistance, 1c
…… Amplifier, 2 …… Constant current circuit, 2a …… Amplifier, 2b …… Load resistance, 2c
…… Amplifier, 3 …… Reference power supply, 4 …… Adder, 5 …… Conductor resistance.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 渡辺 正義 東京都大田区蒲田４丁目19番７号 安藤 電気株式会社内 審査官 張谷 雅人 (56)参考文献 特開 昭62−125415（ＪＰ，Ａ) 実開 昭63−90172（ＪＰ，Ｕ) 特公 昭46−39187（ＪＰ，Ｂ２) ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masayoshi Watanabe 4-19-7 Kamata, Ota-ku, Tokyo Masato Hariya (56) References, Ando Electric Co., Ltd. References JP-A-62-125415 (JP, A) ) Actually open Sho 63-90172 (JP, U) Japanese Patent Sho 46-39187 (JP, B2)
Claims (1)
幅器の出力と導体抵抗の第１の端部の間に接続する第１
の負荷抵抗と、第１の端部を入力に接続し、出力を第１
の増幅器の入力に接続する入出力が同相の第２の増幅器
とで構成する第１の定電流回路と、 入出力が同相の第３の増幅器と、第３の増幅器の出力と
前記導体抵抗の第２の端部の間に接続する第２の負荷抵
抗と、第２の端部を入力に接続し、出力を第３の増幅器
の入力に接続する入出力が同相の第４の増幅器で構成す
る第２の定電流回路と、 第１の増幅器の入力に接続される基準電源と、 前記基準電源の出力Voと、第１の端部の電圧＋ΔVea
と、第２の端部の電圧−ΔVebとを加算し、極性を反転
し、加算出力を第３の増幅器の入力に接続する加算器と
を備えることを特徴とする平衡型定電流回路。1. A first amplifier whose input and output are in phase, and a first amplifier which is connected between the output of the first amplifier and the first end of the conductor resistance.
Connect the load resistance and the first end to the input and connect the output to the first
A first constant current circuit having an input / output connected to the input of the second amplifier and a second amplifier having the same phase, a third amplifier having the same input / output, and an output of the third amplifier and the conductor resistor A second load resistor connected between the second ends, and a fourth amplifier having the same input / output connecting the second end to the input and connecting the output to the input of the third amplifier. A second constant current circuit, a reference power source connected to the input of the first amplifier, an output Vo of the reference power source, and a voltage at the first end + ΔVea
And a voltage at the second end −ΔVeb are added, the polarity is inverted, and an adder for connecting the addition output to the input of the third amplifier is provided.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62080193A JP2520379B2 (en) | 1987-04-01 | 1987-04-01 | Balanced constant current circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62080193A JP2520379B2 (en) | 1987-04-01 | 1987-04-01 | Balanced constant current circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63245703A JPS63245703A (en) | 1988-10-12 |
| JP2520379B2 true JP2520379B2 (en) | 1996-07-31 |
Family
ID=13711547
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62080193A Expired - Lifetime JP2520379B2 (en) | 1987-04-01 | 1987-04-01 | Balanced constant current circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2520379B2 (en) |
-
1987
- 1987-04-01 JP JP62080193A patent/JP2520379B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63245703A (en) | 1988-10-12 |
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