JPH0342825B2 - - Google Patents
Info
- Publication number
- JPH0342825B2 JPH0342825B2 JP59158156A JP15815684A JPH0342825B2 JP H0342825 B2 JPH0342825 B2 JP H0342825B2 JP 59158156 A JP59158156 A JP 59158156A JP 15815684 A JP15815684 A JP 15815684A JP H0342825 B2 JPH0342825 B2 JP H0342825B2
- Authority
- JP
- Japan
- Prior art keywords
- voltage
- current
- circuit
- amplifier
- line terminals
- 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
- 238000010586 diagram Methods 0.000 description 9
- 230000003321 amplification Effects 0.000 description 5
- 238000003199 nucleic acid amplification method Methods 0.000 description 5
- 239000003990 capacitor Substances 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 238000009434 installation Methods 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M1/00—Substation equipment, e.g. for use by subscribers
- H04M1/60—Substation equipment, e.g. for use by subscribers including speech amplifiers
- H04M1/6025—Substation equipment, e.g. for use by subscribers including speech amplifiers implemented as integrated speech networks
Landscapes
- Engineering & Computer Science (AREA)
- Signal Processing (AREA)
Description
【発明の詳細な説明】
産業上の利用分野
本発明は、電話機回路、特に増幅素子を有する
電子化された電話機回路（以下「電子化回路」と
いう。）に関するものである。DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a telephone circuit, and particularly to an electronic telephone circuit having an amplifier element (hereinafter referred to as "electronic circuit").
従来技術とその問題点
従来、増幅素子（例えば送話増幅器及び（又
は）受話増幅器としてのトランジスタ）を有する
電子化回路は、通話電流に対して抵抗型の負荷と
なるように構成されていた。第３図は、このよう
な電子化回路の従来例を示す略式回路図である。
同図において、Ｌ１は正の局線端子、Ｌ２は負の
局線端子、Ｒ１〜Ｒ６は抵抗器（Ｒ３は基準抵抗
器）、Ｃ１〜Ｃ３はコンデンサ、Trは送話増幅用
トランジスタ、１は演算増幅器（オペアンプ）、
２は側音平衡回路綱、３は受話増幅器、４は送話
器、５は受話器を示す。両局線端子Ｌ１，Ｌ２間
の電圧VLは図のように抵抗器Ｒ１，Ｒ２により
電圧Ｖ１に分圧され、この電圧Ｖ１はオペアンプ
１の一方の入力例えば非反転入力に供給される。
オペアンプ１の他方の反転入力には、出力側にお
ける基準抵抗器Ｒ３の流端電圧Ｖ２が抵抗器Ｒ５
を介して帰還されると共に、送話器４の出力電圧
が供給されている。したがつて、オペアンプ１
は、電圧Ｖ１とＶ２とが等しくなるように作用す
ると共に送話電流を増幅用トランジスタTrのベ
ースに供給する。BACKGROUND ART Conventionally, an electronic circuit having an amplification element (for example, a transistor as a transmitting amplifier and/or a receiving amplifier) has been configured to serve as a resistive load for the transmitting current. FIG. 3 is a schematic circuit diagram showing a conventional example of such an electronic circuit.
In the figure, L1 is a positive station line terminal, L2 is a negative station line terminal, R1 to R6 are resistors (R3 is a reference resistor), C1 to C3 are capacitors, Tr is a transmission amplification transistor, and 1 is a operational amplifier (op amp),
2 is a sidetone balance circuit, 3 is a receiver amplifier, 4 is a transmitter, and 5 is a receiver. As shown in the figure, the voltage V L between the two station line terminals L1 and L2 is divided into a voltage V1 by resistors R1 and R2, and this voltage V1 is supplied to one input of the operational amplifier 1, for example, a non-inverting input.
The current end voltage V2 of the reference resistor R3 on the output side is connected to the other inverting input of the operational amplifier 1 through the resistor R5.
The output voltage of the transmitter 4 is also supplied. Therefore, operational amplifier 1
acts so that the voltages V1 and V2 become equal, and supplies a transmitting current to the base of the amplification transistor Tr.
このような回路において、通話電流ILと局線端
子間電圧VLとの関係は、次式で表される。 In such a circuit, the relationship between the communication current I L and the voltage V L between the station line terminals is expressed by the following equation.
VL＝（R3／R2）（R1＋R2）IL ……(1)
第４図は、この関係を示すVL−IL特性図であ
る。この図から分かるように、通話電流ILが減少
すると局線端子間電圧VLは電流ILに正比例して減
少する。したがつて、通常の電流条件で電子化回
路の直流抵抗値を低くしようとすると、低通話電
流時に電子化回路内部の送話及び（又は）受話増
幅器の最低動作電圧を確保できなくなり、遠端設
置条件でのブランチ使用が不可能になり、また、
低通話電流でも安定に動作させようとすれば、電
子化回路の直流抵抗値を高くしなければならない
という欠点があつた。 V L = (R3/R2) (R1 + R2) I L (1) Fig. 4 is a V L - I L characteristic diagram showing this relationship. As can be seen from this figure, when the communication current I L decreases, the voltage V L between the station line terminals decreases in direct proportion to the current I L. Therefore, if you try to lower the DC resistance value of the electronic circuit under normal current conditions, you will not be able to secure the minimum operating voltage of the transmitting and/or receiving amplifier inside the electronic circuit at low talking currents, and the far end Branch use becomes impossible under the installation conditions, and
In order to operate stably even at low communication currents, the disadvantage was that the DC resistance value of the electronic circuit had to be increased.
問題点を解決するための手段及びその作用
本発明は、上述の如き欠点を除去することを目
的とし、そのため、通常の電流条件のもとでは従
来技術と互換性をもたせて抵抗型の負荷性であ
り、低電流条件では電子化回路内部の送話及び
（又は）受話増幅器の最低動作電圧を確保するた
めに定電圧型の負荷特性となるように電子化回路
を構成した。このように構成すれば、低通話電流
でも安定して動作する電子化回路を得ることがで
きる。以下、図示の実施例に基づいて本発明を具
体的に説明する。MEANS FOR SOLVING THE PROBLEMS AND THEIR OPERATION The present invention aims to eliminate the above-mentioned drawbacks and, therefore, provides a resistance-type load capability that is compatible with the prior art under normal current conditions. Under low current conditions, the electronic circuit was configured to have a constant voltage type load characteristic in order to ensure the minimum operating voltage of the transmitting and/or receiving amplifiers inside the electronic circuit. With this configuration, it is possible to obtain an electronic circuit that operates stably even at low communication currents. Hereinafter, the present invention will be specifically explained based on illustrated embodiments.
実施例
第１図は、本発明の好適な実施例を示す略式回
路図である。この図において、第３図と対応する
部分には同一の符号を付した。本例において第３
図の回路に加えられた素子は、抵抗器Ｒ７及びＲ
８、コンデンサＣ４、ダイオードＤ１及びＤ２並
びに定電圧ダイオードＤ３である。すなわち、オ
ペアンプ１の反転入力に、基準抵抗器Ｒ３の両端
電圧Ｖ２及び定電圧ダイオードＤ３の両端電圧Ｖ
３がそれぞれダイオードＤ１及びＤ２を介し抵抗
器Ｒ５を通して供給される。こうすると、オペア
ンプ１は、局線端子間電圧VLを抵抗器Ｒ１とＲ
２で分圧した電圧Ｖ１が基準抵抗器Ｒ３にかかる
電圧Ｖ２と定電圧Ｖ３のいずれか高い方の電圧と
等しくなるように働く。すなわち、ダイオードＤ
１，Ｄ２を順方向電圧降下がない理想的ダイオー
ドとした場合、通話電流ILが或る一定種より多い
ときにはＶ２＞Ｖ３となるように設定しておけ
ば、VL−IL特性は、このILの一定値までは上記(1)
式で表わされ第４図に示す従来のものと同じにな
る。一方、通話電流ILがその一定値より減少する
とＶ２＜Ｖ３となるが、この場合のVL−IL特性は
次式で表わされる。Embodiment FIG. 1 is a schematic circuit diagram illustrating a preferred embodiment of the invention. In this figure, parts corresponding to those in FIG. 3 are given the same reference numerals. In this example, the third
The elements added to the circuit shown are resistors R7 and R
8, a capacitor C4, diodes D1 and D2, and a constant voltage diode D3. That is, the voltage V2 across the reference resistor R3 and the voltage V2 across the constant voltage diode D3 are applied to the inverting input of the operational amplifier 1.
3 are supplied through resistor R5 via diodes D1 and D2, respectively. In this way, operational amplifier 1 connects the voltage V L between the station line terminals to resistors R1 and R
The voltage V1 divided by 2 is equal to the higher of the voltage V2 applied to the reference resistor R3 and the constant voltage V3. That is, diode D
1. If D2 is an ideal diode with no forward voltage drop, if the talking current I L is set to be greater than a certain level, V2>V3, then the V L - I L characteristic is The above (1) applies up to a certain value of I L.
It is expressed by the formula and is the same as the conventional one shown in FIG. On the other hand, when the communication current I L decreases below the constant value, V2<V3, and the V L -I L characteristic in this case is expressed by the following equation.
VL＝V3（R1＋R2）／R2 ……(2)
ここに、電圧Ｖ３は電流ILに無関係な一定値で
あるから、電圧VLも電流ILに無関係に一定とな
る。 V L = V3 (R1 + R2)/R2 (2) Here, since the voltage V3 is a constant value independent of the current I L , the voltage V L is also constant independent of the current I L.
第２図は、上記実施例のVL−IL特性を示す図で
ある。同図において、は上述した通話電流ILの
一定値を示す。すなわち、電流ILがのときＶ２
＝Ｖ３となり、は負荷特性の変化点となる。上
記実施例においては、通常の電流条件が20ｍＡか
ら約100ｍＡ程度であることを考慮して点を20
ｍＡとし、電話機の直流抵抗値を220Ω以下とす
るため点における電圧VLの値を約3Vとした。 FIG. 2 is a diagram showing the V L -I L characteristics of the above embodiment. In the figure, indicates the constant value of the above-mentioned communication current I L. That is, when the current I L is V2
=V3, and becomes the point of change in the load characteristics. In the above example, considering that the normal current condition is about 20 mA to about 100 mA, the points are set at 20 mA.
mA, and the voltage V L at the point was set to about 3 V in order to keep the direct current resistance of the telephone set to 220 Ω or less.
なお、第１図において、コンデンサＣ３は直流
阻止作用をし、抵抗器Ｒ８は定電圧ダイオードＤ
３の両端に定電圧V3を発生させるために設けた
ものである。定電圧V3を発生させるためには必
ずしも定電圧ダイオードＤ３を用いる必要はな
く、例えば電池など他の定電圧源を使用すること
もできる。その場合は、抵抗器Ｒ８は不要とな
る。 In FIG. 1, capacitor C3 acts as a direct current blocker, and resistor R8 acts as a constant voltage diode D.
This is provided to generate a constant voltage V 3 across the terminal 3. In order to generate the constant voltage V3 , it is not necessarily necessary to use the constant voltage diode D3, and other constant voltage sources such as a battery can also be used. In that case, resistor R8 becomes unnecessary.
なお、本発明は、上記の実施例に限らず、特許
請求の範囲内において種々の変形・変更をしうる
ものである。 Note that the present invention is not limited to the above-described embodiments, and can be variously modified and changed within the scope of the claims.
以上説明したところから明らかなように、本発
明によれば、通常の電流条件で電子化回路の直流
抵抗値を高くすることなく、低通話電流で安定に
動作する電話機回路が得られるので、遠端設置条
件でも電話機のブランチ使用が可能となる。ま
た、本発明をボタン電話装置の内線電話機等に適
用すれば、装置全体の消費電力を低下させること
ができる。 As is clear from the above explanation, according to the present invention, it is possible to obtain a telephone circuit that operates stably at a low communication current without increasing the DC resistance value of the electronic circuit under normal current conditions. Branch use of the telephone is possible even in edge installation conditions. Furthermore, if the present invention is applied to an extension telephone of a key telephone device, the power consumption of the entire device can be reduced.
第１図は本発明の好適な実施例を示す略式回路
図、第２図はそのVL−IL特性図、第３図は従来例
を示す略式回路図、第４図はそのVL−IL特性図で
ある。
Ｌ１，Ｌ２……局線端子、VL……局線端子間
電圧、Ｖ１……局線端子間電圧を分圧した電圧、
１……演算増幅器、Tr……増幅素子、Ｒ３……
基準抵抗器、Ｖ２……増幅素子と基準抵抗器の中
間接続点の電圧、４……送話器、Ｄ３……定電圧
源としての定電圧ダイオード、Ｖ３……定電圧源
電圧。
Fig. 1 is a schematic circuit diagram showing a preferred embodiment of the present invention, Fig. 2 is its V L -I L characteristic diagram, Fig. 3 is a schematic circuit diagram showing a conventional example, and Fig. 4 is its V L -I L characteristic diagram. It is an IL characteristic diagram. L1, L2: Office line terminal, V L : Voltage between office line terminals, V1: Voltage obtained by dividing the voltage between office line terminals,
1...Operation amplifier, Tr...Amplification element, R3...
Reference resistor, V2... Voltage at the intermediate connection point between the amplification element and reference resistor, 4... Transmitter, D3... Constant voltage diode as a constant voltage source, V3... Constant voltage source voltage.
Claims (1)
網において、通話電流が多いときには上記回路網
の局線端子間電圧が通話電流と正比例して変化す
る抵抗型の負荷となり、通話電流が少ないときに
は上記回路網の局線端子間電圧が送話アンプと受
話アンプの動作電圧を確保するように通話電流に
よらず一定となる定電圧型の負荷となる様に構成
されたことを特徴とする電話機回路。1 In a telephone circuit network having a transmitting amplifier and a receiving amplifier, when the talking current is large, the voltage between the office line terminals of the circuit becomes a resistive load that changes in direct proportion to the talking current, and when the talking current is low, the voltage between the station line terminals of the circuit changes in direct proportion to the talking current. A telephone circuit characterized in that the voltage between the station line terminals of the network is configured to be a constant voltage type load that is constant regardless of the communication current so as to ensure the operating voltage of the transmitting amplifier and the receiving amplifier.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15815684A JPS6135661A (en) | 1984-07-28 | 1984-07-28 | Telephone set circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15815684A JPS6135661A (en) | 1984-07-28 | 1984-07-28 | Telephone set circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6135661A JPS6135661A (en) | 1986-02-20 |
| JPH0342825B2 true JPH0342825B2 (en) | 1991-06-28 |
Family
ID=15665486
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15815684A Granted JPS6135661A (en) | 1984-07-28 | 1984-07-28 | Telephone set circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6135661A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2181324B (en) * | 1985-10-07 | 1989-02-01 | Motorola Inc | Telephone circuits |
| FR2686757B1 (en) * | 1992-01-29 | 1997-03-28 | Sgs Thomson Microelectronics | CURRENT MODULATOR OF A TELEPHONE LINE. |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5494213A (en) * | 1978-01-10 | 1979-07-25 | Nec Corp | Amplifier for transmitter |
-
1984
- 1984-07-28 JP JP15815684A patent/JPS6135661A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5494213A (en) * | 1978-01-10 | 1979-07-25 | Nec Corp | Amplifier for transmitter |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6135661A (en) | 1986-02-20 |
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