JPS623605B2 - - Google Patents
Info
- Publication number
- JPS623605B2 JPS623605B2 JP52043852A JP4385277A JPS623605B2 JP S623605 B2 JPS623605 B2 JP S623605B2 JP 52043852 A JP52043852 A JP 52043852A JP 4385277 A JP4385277 A JP 4385277A JP S623605 B2 JPS623605 B2 JP S623605B2
- Authority
- JP
- Japan
- Prior art keywords
- transistors
- differential amplifier
- constant current
- differential
- signal component
- 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
- 230000003321 amplification Effects 0.000 claims description 3
- 238000003199 nucleic acid amplification method Methods 0.000 claims description 3
- 238000001514 detection method Methods 0.000 claims 2
- 239000003990 capacitor Substances 0.000 description 4
- 230000008878 coupling Effects 0.000 description 3
- 238000010168 coupling process Methods 0.000 description 3
- 238000005859 coupling reaction Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/45—Differential amplifiers
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Amplifiers (AREA)
Description
【発明の詳細な説明】
この発明は、差動増幅器の入力端子にバイアス
電圧を与える回路に関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a circuit for applying a bias voltage to the input terminals of a differential amplifier.
差動増幅器の場合、一般の増幅器と異なり増幅
の対象となる差動信号成分の他に、不要な同相信
号成分をも入力信号として考慮に入れなければな
らない。従つて、差動増幅器のダイナミツクレン
ジは、「差動信号成分+同相信号成分」の振幅分
が必要とされる。 In the case of a differential amplifier, unlike a general amplifier, in addition to the differential signal component to be amplified, an unnecessary common-mode signal component must also be taken into account as an input signal. Therefore, the dynamic range of the differential amplifier requires the amplitude of "differential signal component + common mode signal component".
通常、差動増幅器内部で同相負帰還回路を形成
するなどの方法により、増幅器の電源電圧まで同
相信号に対するダイナミツクレンジを確保するこ
とも可能である。一方、同相信号成分の振幅は差
動信号成分の振幅を上まわることもめずらしくな
く、又、差動増幅器の電源電圧を超えることもま
れではない。こういう場合、不要である同相信号
成分の振幅分まで入力ダイナミツクレンジを確保
するのは、しばしば不可能であり、又、不経済な
ことである。 Usually, it is also possible to secure the dynamic range for the common mode signal up to the power supply voltage of the amplifier by forming a common mode negative feedback circuit inside the differential amplifier. On the other hand, it is not uncommon for the amplitude of the common-mode signal component to exceed the amplitude of the differential signal component, and it is not uncommon for the amplitude to exceed the power supply voltage of the differential amplifier. In such cases, it is often impossible and uneconomical to ensure input dynamics range up to the amplitude of unnecessary in-phase signal components.
この発明は、差動増幅器の入力端子に必要なバ
イアス電圧を与えるとともに、差動増幅器に加わ
る同相信号成分のみを検出して、これにある基準
電圧と比較し、入力端子の電位が同相信号成分に
より変化することを妨げ、予め設定された電圧を
維持するように制御することにより、前述の従来
の欠点である同相信号成分に対するダイナミツク
レンジを確保することを可能とする差動増幅器を
提供することを目的とする。 This invention applies the necessary bias voltage to the input terminals of the differential amplifier, detects only the common-mode signal component applied to the differential amplifier, and compares it with a reference voltage, so that the potential of the input terminals is in the same phase. A differential amplifier that makes it possible to secure the dynamic range for the common-mode signal component, which is the drawback of the conventional method, by preventing changes due to signal components and controlling the voltage to maintain a preset voltage. The purpose is to provide
以下に本発明の実施例について図面を参照して
説明する。第1図は、その一実施例を示す回路図
である。図中、1,2はトランジスタであり、当
該差動増幅器を構成している。3は基準電圧を与
える電源であり、4は差動増幅器内の接続点であ
る15の電位と、基準電圧3の電圧との差を増幅
し、接続点15の電位変化と同じ位相の電位変化
を出力するようになつている誤差増幅器であり、
トランジスタ11,12を介して、差動増幅器の
入力点13,14に定電流電源9,10とともに
接続されて、負帰還ループを形成する。17,1
8は結合コンデンサであり、5,6,7,8はバ
イアス抵抗である。 Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram showing one embodiment thereof. In the figure, 1 and 2 are transistors, which constitute the differential amplifier. 3 is a power supply that provides a reference voltage, and 4 is a power supply that amplifies the difference between the potential at connection point 15 in the differential amplifier and the voltage at reference voltage 3, and generates a potential change in the same phase as the potential change at connection point 15. It is an error amplifier designed to output
It is connected to input points 13 and 14 of the differential amplifier together with constant current power supplies 9 and 10 via transistors 11 and 12 to form a negative feedback loop. 17,1
8 is a coupling capacitor, and 5, 6, 7, and 8 are bias resistors.
差動増幅器の入力点13,14のバイアス電圧
はトランジスタ1,2と抵抗7,8を通して、接
続点15において検出され、基準電圧3の電圧と
比較し誤差増幅器4とトランジスタ11,12を
介して制御されることになり、接続点15の電位
と基準電圧3の電圧が一致したところで安定す
る。従つて、基準電圧3の電圧と接続点15の電
位を選択することにより、差動増幅器の入力点1
3,14のバイアス電圧は設定される。 The bias voltage at the input points 13 and 14 of the differential amplifier is detected at the connection point 15 through the transistors 1 and 2 and the resistors 7 and 8, and compared with the voltage of the reference voltage 3, the bias voltage is detected through the error amplifier 4 and the transistors 11 and 12. The voltage is controlled and stabilized when the potential at the connection point 15 and the voltage at the reference voltage 3 match. Therefore, by selecting the voltage of the reference voltage 3 and the potential of the connection point 15, the input point 1 of the differential amplifier
Bias voltages 3 and 14 are set.
図中の1と2、5と6、7と8、9と10、1
1と12のそれぞれの特性がそろつていれば、1
3,14の電位は充分平衡させることができる。
今、端子19,20に同相信号成分が印加され
て、入力点13,14の電位が同相変動をうける
と、前述したように、その変動分は、接続点15
において同相信号成分として検出され、誤差増幅
器4により増幅されてトランジスタ11,12を
介し、入力点13,14に逆位相にて加えられる
負帰還ループにより、入力点13,14の電位の
変動を妨げるように制御される。この帰還ループ
のループ利得を大きくすれば入力点13,14に
おける電位変動は充分抑圧することが可能とな
る。つまり、第1図の回路で回路の各部の平衡を
とり、接続点15にては同相信号成分のみ検出す
るようにすれば、差動増幅器の入力点13,14
の電位を、端子19,20に印加された同相信号
成分に対しては応動しないようにすることがで
き、印加された同相信号成分の電圧は、結合コン
デンサ17,18のそれぞれの両端にほぼそのま
まの電圧として現出することになる。なお、接続
点15では差動信号成分は現われないので、この
負帰還ループは入力点13,14における差動信
号成分に対しては応動しないこととなり、差動信
号成分の増幅には支障をきたさない。 1 and 2, 5 and 6, 7 and 8, 9 and 10, 1 in the diagram
If the characteristics of 1 and 12 are the same, then 1
The potentials of 3 and 14 can be sufficiently balanced.
Now, when an in-phase signal component is applied to the terminals 19 and 20 and the potentials at the input points 13 and 14 undergo an in-phase variation, as described above, the variation is
is detected as an in-phase signal component at , is amplified by error amplifier 4, and is applied to input points 13 and 14 in opposite phase via transistors 11 and 12. Through a negative feedback loop, fluctuations in the potential at input points 13 and 14 are suppressed. controlled to prevent. By increasing the loop gain of this feedback loop, potential fluctuations at input points 13 and 14 can be sufficiently suppressed. In other words, if each part of the circuit is balanced in the circuit shown in Fig. 1, and only the common-mode signal component is detected at the connection point 15, then
The voltage of the applied common-mode signal component can be made to be unresponsive to the common-mode signal component applied to the terminals 19 and 20, and the voltage of the applied common-mode signal component is applied across the coupling capacitors 17 and 18, respectively. It will appear as almost the same voltage. Note that since the differential signal component does not appear at the connection point 15, this negative feedback loop does not respond to the differential signal component at the input points 13 and 14, and the amplification of the differential signal component is not hindered. do not have.
以上、述べたように本発明によれば、差動増幅
器の入力端子に必要なバイアス電圧を与えるとと
もに、差動増幅器に加わる同相信号成分の為のダ
イナミツクレンジへの配慮を大幅に軽減できると
いう効果がある。 As described above, according to the present invention, it is possible to provide the necessary bias voltage to the input terminals of the differential amplifier, and to significantly reduce the need to consider the dynamic range due to the common-mode signal component applied to the differential amplifier. There is an effect.
結合コンデンサ17,18は差動増幅器を駆動
する際の駆動源インピーダンスに置き換えても、
本発明の効果は変わらないことは今までの説明よ
り容易に類推できる。又、第1図中でトランジス
タ1,2によつて形成される差動増幅器は、差動
増幅器の形を規定するものではなく、本発明は一
般の差動増幅器に対して適用できるものである。
本発明は、平衡対線路に挿入されるトランスレス
中継器において、特に有用となる。 Even if the coupling capacitors 17 and 18 are replaced with the drive source impedance when driving the differential amplifier,
It can be easily inferred from the previous explanation that the effects of the present invention remain the same. Furthermore, the differential amplifier formed by transistors 1 and 2 in FIG. 1 does not define the shape of the differential amplifier, and the present invention can be applied to general differential amplifiers. .
The present invention is particularly useful in transformerless repeaters inserted into balanced pair lines.
第1図は本発明の一実施例を示す。
図中、1,2,11,12……トランジスタ、
5,6,7,8……抵抗、3……電源、4……誤
差増幅器、9,10,16……定電流源、13,
14,15……接続点、17,18……コンデン
サ、19,20……入力端子。
FIG. 1 shows an embodiment of the invention. In the figure, 1, 2, 11, 12...transistors,
5, 6, 7, 8... Resistor, 3... Power supply, 4... Error amplifier, 9, 10, 16... Constant current source, 13,
14, 15... connection point, 17, 18... capacitor, 19, 20... input terminal.
Claims (1)
1および第2の定電流源と接続された第1および
第2のトランジスタと;前記第1の定電流源と前
記第1のトランジスタのコレクタとの接続点に接
続した第1の入力端子と、前記第2の定電流源と
前記第2のトランジスタのコレクタとの接続点に
接続した第2の入力端子とを有し前記第1および
第2の入力端子にベースが接続された1対のトラ
ンジスタを備えた差動増幅手段と;前記差動幅手
段のトランジスタのエミツタに各々接続され前記
第1および第2の入力端子に印加される第1およ
び第2の入力信号の同相信号成分を検出する検出
手段と;該検出手段で検出した同相信号成分と基
準電圧とを比較し増幅し結果を前記第1および第
2のトランジスタのベースに出力する比較増幅手
段とから構成したことを特徴とする差動増幅器。1 first and second constant current sources; first and second transistors connected to the first and second constant current sources, respectively; said first constant current source and said first transistor; a first input terminal connected to a connection point with the collector; and a second input terminal connected to a connection point between the second constant current source and the collector of the second transistor; differential amplification means comprising a pair of transistors whose bases are connected to a second input terminal; each connected to the emitters of the transistors of the differential width means and applied to the first and second input terminals; a detection means for detecting common-mode signal components of the first and second input signals; comparing and amplifying the common-mode signal components detected by the detection means with a reference voltage; and transmitting the results to the first and second transistors; A differential amplifier comprising a comparison amplification means for outputting an output to a base.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP4385277A JPS53128960A (en) | 1977-04-15 | 1977-04-15 | Differential amplifier |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP4385277A JPS53128960A (en) | 1977-04-15 | 1977-04-15 | Differential amplifier |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS53128960A JPS53128960A (en) | 1978-11-10 |
JPS623605B2 true JPS623605B2 (en) | 1987-01-26 |
Family
ID=12675235
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP4385277A Granted JPS53128960A (en) | 1977-04-15 | 1977-04-15 | Differential amplifier |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS53128960A (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2946952A1 (en) * | 1979-11-21 | 1981-06-04 | Philips Patentverwaltung Gmbh, 2000 Hamburg | DIFFERENTIAL AMPLIFIER |
US4533876A (en) * | 1983-10-18 | 1985-08-06 | American Microsystems, Inc. | Differential operational amplifier with common mode feedback |
-
1977
- 1977-04-15 JP JP4385277A patent/JPS53128960A/en active Granted
Also Published As
Publication number | Publication date |
---|---|
JPS53128960A (en) | 1978-11-10 |
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