JPH0339928Y2 - - Google Patents
Info
- Publication number
- JPH0339928Y2 JPH0339928Y2 JP10496784U JP10496784U JPH0339928Y2 JP H0339928 Y2 JPH0339928 Y2 JP H0339928Y2 JP 10496784 U JP10496784 U JP 10496784U JP 10496784 U JP10496784 U JP 10496784U JP H0339928 Y2 JPH0339928 Y2 JP H0339928Y2
- Authority
- JP
- Japan
- Prior art keywords
- operational amplifier
- power supply
- voltage
- circuit
- transistor
- 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
- 230000010355 oscillation Effects 0.000 description 6
- 238000010586 diagram Methods 0.000 description 2
- 230000015556 catabolic process Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
Description
【考案の詳細な説明】
〈産業上の利用分野〉
この考案は動作電圧範囲がきわめて広く、かつ
高速、高精度に動作する電圧フオロワ回路に関す
る。例えば高インピーダンスの出力端子に低イン
ピーダンスの回路を接続する場合、高インピーダ
ンスの回路の状態が変化し、その電圧検出に誤差
が生じるのを防ぐために上記端子と回路の間に挿
入される入力バツフアとして使用されるもので、
特に直流特性の優れた演算増幅器を用いて高速、
高精度でかつ動作電圧範囲を大きくとれる電圧フ
オロワ回路を提供しようとするものである。[Detailed Description of the Invention] <Industrial Field of Application> This invention relates to a voltage follower circuit that has an extremely wide operating voltage range and operates at high speed and with high precision. For example, when connecting a low impedance circuit to a high impedance output terminal, an input buffer is inserted between the above terminal and the circuit to prevent the state of the high impedance circuit from changing and errors in voltage detection. It is used,
High speed, using operational amplifiers with particularly excellent DC characteristics.
The present invention aims to provide a voltage follower circuit with high accuracy and a wide operating voltage range.
〈従来技術の説明〉
演算増幅器単体の動作電圧の範囲を超える振幅
を有する信号を処理する電圧フオロワ回路として
例えば第２図に示すものがある。<Description of Prior Art> For example, there is a voltage follower circuit shown in FIG. 2 that processes a signal having an amplitude exceeding the operating voltage range of a single operational amplifier.
これは直流特性の優れた演算増幅器２１の出力
端子と各電源端子との間にそれぞれ第一ツエナダ
イオード４１と第一トランジスタ３１から成る第
一ブートストラツプ回路と、第二ツエナダイオー
ド４２と第二トランジスタ３２から成る第二ブー
トストラツプ回路を設けて、演算増幅器２１の正
及び負の電源端子に供給される電圧がその出力電
圧に追従して変化するようにしたものである。ま
た第一抵抗器５１、第二抵抗器５２、第三抵抗器
５３、第四抵抗器５４、第五抵抗器５５、第三ト
ランジスタ３３、第四トランジスタ３４、第一ダ
イオード４３及び第二ダイオード４４から成る回
路で、ツエナダイオード４１，４２に定電流が流
れるようにして、演算増幅器２１の出力電圧にか
かわらずそれらのツエナ電圧が一定になるように
している。従つて入力端子１１からの電圧Vioに
追従して演算増幅器２１の電源電圧が変化するの
で、電圧Vioの振幅は各トランジスタの耐圧と電
源電圧の許す限り大きくすることができる。また
入力電圧Vioに追従して演算増幅器２１の電源電
圧も変化するので、見かけ上の同相成分が加わら
なくなり、電圧フオロワ回路としての同相信号除
去比も問題とならない。 This includes a first bootstrap circuit consisting of a first Zener diode 41 and a first transistor 31, a second Zener diode 42, and a second transistor between the output terminal of the operational amplifier 21 having excellent DC characteristics and each power supply terminal. A second bootstrap circuit consisting of 32 is provided so that the voltage supplied to the positive and negative power supply terminals of operational amplifier 21 changes in accordance with its output voltage. Also, a first resistor 51, a second resistor 52, a third resistor 53, a fourth resistor 54, a fifth resistor 55, a third transistor 33, a fourth transistor 34, a first diode 43, and a second diode 44. In this circuit, a constant current flows through the Zener diodes 41 and 42 so that their Zener voltage remains constant regardless of the output voltage of the operational amplifier 21. Therefore, since the power supply voltage of the operational amplifier 21 changes following the voltage V io from the input terminal 11, the amplitude of the voltage V io can be made as large as the withstand voltage of each transistor and the power supply voltage allow. Further, since the power supply voltage of the operational amplifier 21 changes in accordance with the input voltage Vio , no apparent common-mode component is added, and the common-mode signal rejection ratio as a voltage follower circuit does not become a problem.
しかし上記の回路では演算増幅器２１の出力端
子からのブートストラツプ回路を経て電源端子に
帰還回路が構成されているために、発振が起こり
やすい。この発振を防ぐために演算増幅器２１の
位相補償用の容量を増やして発振帯域を狭めた
り、また帰還回路内に位相補償を施して発振を防
止している。従つて従来の電圧フオロワ回路でも
高精度化、高耐圧化は可能であるが、高速応答に
関しては期待できないという欠点がある。 However, in the above circuit, since a feedback circuit is constructed from the output terminal of the operational amplifier 21 via the bootstrap circuit to the power supply terminal, oscillation is likely to occur. To prevent this oscillation, the phase compensation capacitance of the operational amplifier 21 is increased to narrow the oscillation band, and the feedback circuit is provided with phase compensation to prevent oscillation. Therefore, although it is possible to achieve high accuracy and high breakdown voltage with conventional voltage follower circuits, there is a drawback that high-speed response cannot be expected.
〈考案の目的〉
この考案は直流特性のすぐれた演算増幅器を用
いて、高速、高精度、動作電圧範囲の広い電圧フ
オロワ回路を提供することを目的とする。<Purpose of the invention> The purpose of this invention is to provide a voltage follower circuit with high speed, high accuracy, and a wide operating voltage range using an operational amplifier with excellent DC characteristics.
〈考案の概要〉
この考案による電圧フオロワ回路は、入力信号
を直流特性の優れた演算増幅器の非反転入力端子
に供給し、出力信号を反転入力端子に帰還して電
圧フオロワ回路を更正すると共に、入力信号を高
速バツフア増幅器を通して、ツエナダイオードと
トランジスタ等から成る電源回路に供給し、該電
源回路の電圧を演算増幅器の電源端子に供給する
ようにしたものである。<Summary of the invention> The voltage follower circuit according to this invention supplies an input signal to the non-inverting input terminal of an operational amplifier with excellent DC characteristics, returns the output signal to the inverting input terminal, and corrects the voltage follower circuit. The input signal is supplied through a high-speed buffer amplifier to a power supply circuit consisting of a Zener diode, a transistor, etc., and the voltage of the power supply circuit is supplied to the power supply terminal of the operational amplifier.
従つてこの考案によれば、演算増幅器の出力側
と電源端子との間に帰還回路が構成されていない
ので、振幅の大きな信号に対しても高精度かつ高
速に応答できる電圧フオロワ回路が得られる。 Therefore, according to this invention, since no feedback circuit is configured between the output side of the operational amplifier and the power supply terminal, a voltage follower circuit that can respond with high precision and high speed even to signals with large amplitude can be obtained. .
〈考案の実施例〉
第１図にこの考案の一実施例を示す。図中、第
２図と同じものは同一符号で示す。これは入力端
子１１からの入力信号を演算増幅器２１の非反転
入力側に供給すると共に、入力信号を高速バツフ
ア２２を通してツエナダイオード４１，４２の接
続点に供給し、その電圧で第一ツエナダイオード
４１と第一トランジスタ３１から成る第一電源回
路と、第二ツエナダイオード４２と第二トランジ
スタ３２から成る第二電源回路とを通じて演算増
幅器２１の正及び負の電源電圧を調整している。
第一抵抗器５１、第二抵抗器５２、第三抵抗器５
３、第四抵抗器５４、第五抵抗器５５、第三トラ
ンジスタ３３、第四トランジスタ３４、第一ダイ
オード４３及び第二ダイオード４４から成る定電
流回路で、ツエナダイオード４１，４２に定電流
を流し、それらのツエナ電圧を一定に保つてい
る。<Example of the invention> Fig. 1 shows an example of the invention. In the figure, the same parts as in FIG. 2 are indicated by the same symbols. This supplies the input signal from the input terminal 11 to the non-inverting input side of the operational amplifier 21, and also supplies the input signal to the connection point between the Zener diodes 41 and 42 through the high-speed buffer 22, and uses that voltage to connect the first Zener diode 41. The positive and negative power supply voltages of the operational amplifier 21 are adjusted through a first power supply circuit consisting of a first transistor 31 and a second Zener diode 42 and a second power supply circuit consisting of a second transistor 32.
First resistor 51, second resistor 52, third resistor 5
3. A constant current circuit consisting of a fourth resistor 54, a fifth resistor 55, a third transistor 33, a fourth transistor 34, a first diode 43, and a second diode 44, in which a constant current is passed through the Zener diodes 41 and 42. , keeping their zener voltage constant.
今、第一ツエナダイオード４１、第二ツエナダ
イオード４２のツエナ電圧をそれぞれV1，V2、
トランジスタ３１，３２のベース・エミツタ間電
圧をVBE、演算増幅器２１の入力電圧をVioと置く
と、演算増幅器２１の正及び負の電源端子にはそ
れぞれV+＝Vio＋（V1−VBE）、V-＝Vio−（V2−
VBE）の電圧が供給される。即ち、演算増幅器２
１の電源電圧は入力電圧に追従して変化するの
で、入力信号の振幅を演算増幅器単体の動作電圧
範囲よりも大きくとることができる。そして演算
増幅器２１として直流特性の優れたものを用いて
いるので同相信号除去比は問題とならない。 Now, the Zener voltages of the first Zener diode 41 and the second Zener diode 42 are respectively V 1 , V 2 ,
If the base-emitter voltage of the transistors 31 and 32 is V BE and the input voltage of the operational amplifier 21 is V io , then the positive and negative power supply terminals of the operational amplifier 21 have V + =V io + (V 1 − V BE ), V - = V io - (V 2 -
A voltage of V BE ) is supplied. That is, operational amplifier 2
Since the power supply voltage of No. 1 changes in accordance with the input voltage, the amplitude of the input signal can be made larger than the operating voltage range of a single operational amplifier. Since the operational amplifier 21 has excellent direct current characteristics, the common-mode signal rejection ratio is not a problem.
また第２図に示された従来の電圧フオロワ回路
と異なり、電源端子への帰還回路が構成されてい
ないので、発振を起こすことがなく、従つて演算
増幅器２１の帯域を制限する必要はない。更に第
２図の演算増幅回路では演算増幅器２１自身の出
力電圧からその電源電圧をブートストラツプして
いたので、回路全体のスルーレートを高くするた
めに演算増幅器２１自身のスルーレートを高くす
る必要があつた。しかし本考案の回路では高速バ
ツフア２２により演算増幅器２１の電源電圧が入
力電圧に追従して変化するので、演算増幅器２１
のスルーレートを高くする必要はない。以上の理
由により高速化することができる。 Further, unlike the conventional voltage follower circuit shown in FIG. 2, since a feedback circuit to the power supply terminal is not configured, oscillation does not occur, and therefore there is no need to limit the band of the operational amplifier 21. Furthermore, in the operational amplifier circuit shown in FIG. 2, the power supply voltage is bootstrapped from the output voltage of the operational amplifier 21 itself, so in order to increase the slew rate of the entire circuit, it is necessary to increase the slew rate of the operational amplifier 21 itself. It was hot. However, in the circuit of the present invention, the power supply voltage of the operational amplifier 21 changes according to the input voltage due to the high-speed buffer 22.
There is no need to increase the slew rate. For the above reasons, the speed can be increased.
高速バツフア２２は演算増幅器２１の電源変動
除去比が期待できるので、そのオフセツト電圧や
同相信号除去比はある程度犠牲にでき、動作電圧
範囲が広く高速応答できればよく、FETやトラ
ンジスタ等を用いた簡単な回路で構成できる。 Since the high-speed buffer 22 can be expected to have the power supply fluctuation rejection ratio of the operational amplifier 21, its offset voltage and common-mode signal rejection ratio can be sacrificed to some extent, and it is only necessary to have a wide operating voltage range and high-speed response. It can be configured with a circuit.
〈考案の効果〉
以上説明したようにこの考案によれば、演算増
幅器として直流特性の優れたものを用い、その電
源電圧は電源回路を通じて入力信号に追従して変
化させているので、同相信号除去比は問題となら
ず、演算増幅器単体の動作電圧範囲よりも広い範
囲で、高精度に動作させることができる。また電
源回路は入力信号を基準としており、演算増幅器
の出力側と電源端子との間に帰還回路が構成され
ない。従つて発振も問題とならないので高速に応
答できる。<Effects of the invention> As explained above, according to this invention, an operational amplifier with excellent DC characteristics is used, and its power supply voltage is changed by following the input signal through the power supply circuit, so that the in-phase signal The rejection ratio is not a problem, and it can be operated with high precision over a wider range of operating voltages than that of a single operational amplifier. Further, the power supply circuit is based on the input signal, and no feedback circuit is configured between the output side of the operational amplifier and the power supply terminal. Therefore, oscillation is not a problem, and a high-speed response can be achieved.
第１図はこの考案による電圧フオロワ回路の一
実施例を示す回路図、第２図は従来の電圧フオロ
ワ回路の回路図である。
１１：入力端子、１２：出力端子、２１：演算
増幅器、２２：高速バツフア、３１：第一トラン
ジスタ、３２：第二トランジスタ、３３：第三ト
ランジスタ、３４：第四トランジスタ、４１：第
一ツエナダイオード、４２：第二ツエナダイオー
ド、４３：第一ダイオード、４４：第二ダイオー
ド、５１：第一抵抗器、５２：第二抵抗器、５
３：第三抵抗器、５４：第四抵抗器、５５：第五
抵抗器。
FIG. 1 is a circuit diagram showing an embodiment of a voltage follower circuit according to this invention, and FIG. 2 is a circuit diagram of a conventional voltage follower circuit. 11: input terminal, 12: output terminal, 21: operational amplifier, 22: high-speed buffer, 31: first transistor, 32: second transistor, 33: third transistor, 34: fourth transistor, 41: first Zener diode , 42: second Zener diode, 43: first diode, 44: second diode, 51: first resistor, 52: second resistor, 5
3: third resistor, 54: fourth resistor, 55: fifth resistor.
Claims (1)
入力端子と出力端子が接続された演算増幅器
と、 Ｂ 上記入力端子の信号を、第１ツエナダイオー
ドと第２ツエナダイオードの接続点に供給する
高速バツフア増幅器と、 Ｃ 上記第１ツエナダイオードとトランジスタか
ら成り、上記演算増幅器の正電源端子に接続す
る第１電源回路と、 Ｄ 上記第２ツエナダイオードとトランジスタか
ら成り、上記演算増幅器の負電源端子に接続す
る第２電源回路と、 から成ることを特徴とする電圧フオロワ回路。[Claims for Utility Model Registration] A: an operational amplifier whose non-inverting input terminal is connected to an input terminal, and whose inverting input terminal and output terminal are connected; a high-speed buffer amplifier that supplies the connection point of the diode; C a first power supply circuit comprising the first Zener diode and a transistor and connected to the positive power supply terminal of the operational amplifier; D comprising the second Zener diode and the transistor; A voltage follower circuit comprising: a second power supply circuit connected to the negative power supply terminal of the operational amplifier;
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10496784U JPS6121122U (en) | 1984-07-11 | 1984-07-11 | voltage follower circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10496784U JPS6121122U (en) | 1984-07-11 | 1984-07-11 | voltage follower circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6121122U JPS6121122U (en) | 1986-02-07 |
| JPH0339928Y2 true JPH0339928Y2 (en) | 1991-08-22 |
Family
ID=30664304
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10496784U Granted JPS6121122U (en) | 1984-07-11 | 1984-07-11 | voltage follower circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6121122U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9322958B2 (en) | 2004-08-27 | 2016-04-26 | Coopervision International Holding Company, Lp | Silicone hydrogel contact lenses |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006345328A (en) * | 2005-06-10 | 2006-12-21 | Hideo Kusakabe | Multistage amplifier |
-
1984
- 1984-07-11 JP JP10496784U patent/JPS6121122U/en active Granted
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9322958B2 (en) | 2004-08-27 | 2016-04-26 | Coopervision International Holding Company, Lp | Silicone hydrogel contact lenses |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6121122U (en) | 1986-02-07 |
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