JPH0131328B2 - - Google Patents
Info
- Publication number
- JPH0131328B2 JPH0131328B2 JP57108221A JP10822182A JPH0131328B2 JP H0131328 B2 JPH0131328 B2 JP H0131328B2 JP 57108221 A JP57108221 A JP 57108221A JP 10822182 A JP10822182 A JP 10822182A JP H0131328 B2 JPH0131328 B2 JP H0131328B2
- Authority
- JP
- Japan
- Prior art keywords
- amplifier
- circuit
- transfer function
- input
- output
- 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
- 239000003990 capacitor Substances 0.000 claims description 2
- 238000010586 diagram Methods 0.000 description 4
Landscapes
- Amplifiers (AREA)
Description
【発明の詳細な説明】
本発明は増幅回路の中でも、特に入力段にエミ
ツタフオロア回路を持つものに関し、その目的は
帯域幅を拡大することにある。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to amplifier circuits, particularly those having an emitter follower circuit in the input stage, and its purpose is to expand the bandwidth.
第１図は従来の前記増幅回路を示し、１，２は
入出力端子、３はエミツタフオロア回路を形成す
るトランジスタ、４は増幅器である。 FIG. 1 shows the conventional amplifier circuit, in which 1 and 2 are input/output terminals, 3 is a transistor forming an emitter follower circuit, and 4 is an amplifier.
このような増幅回路は増幅器４の入力にエミツ
タフオロア回路を有するため高い入力インピーダ
ンスを持つが、トランジスタ３のコレクタ出力容
量Cpbが増幅器４の入力容量Ciとなるため、高い
信号源インピーダンスを持つ信号源に接続する場
合には帯域幅が制限されてしまう欠点がある。つ
まり、第１図の増幅回路を第２図に示すような信
号源インピーダンスRGを持つ信号源５に接続す
ると、増幅回路自体の遮断周波数fc1が高くとも、
信号源インピーダンスRGと入力容量Ciの積で決
まる遮断周波数fcに制限を受け、広い帯域を得る
ことができないもので、遮断周波数fcは、
fc＝１／2π・Cpb・RG ……
と表わすことができる。よつて、信号源インピー
ダンスRGとコレクタ出力容量Cpbが大きいほど帯
域幅が低下するのが現状である。 Such an amplifier circuit has a high input impedance because it has an emitter follower circuit at the input of the amplifier 4, but since the collector output capacitance C pb of the transistor 3 becomes the input capacitance Ci of the amplifier 4, the signal source has a high signal source impedance. The disadvantage is that the bandwidth is limited when connecting to In other words, when the amplifier circuit shown in Fig. 1 is connected to the signal source 5 having the signal source impedance R G as shown in Fig. 2, even if the cut-off frequency fc 1 of the amplifier circuit itself is high,
It is limited by the cutoff frequency fc determined by the product of the signal source impedance R G and the input capacitance Ci, and cannot obtain a wide band. The cutoff frequency fc is f c = 1/2π・C pb・R G …… It can be expressed as Therefore, the current situation is that the larger the signal source impedance R G and the collector output capacitance C pb are, the lower the bandwidth is.
本発明は、エミツタフオロア回路を介して信号
源から信号が入力される増幅器と、この増幅器の
出力端子に入力端子が接続され出力端子が前記エ
ミツタフオロア回路を構成するトランジスタのコ
レクタ端子に接続された位相回路とを設け、前記
位相回路の伝達関数を前記増幅器の伝達関数の逆
数に設定して前記増幅器の出力端子から出力信号
を得ることを特徴とし、信号源インピーダンスに
よつて周波数帯域制限を受けることがなく、増幅
器本来の遮断周波数まで有効に利用した増幅がで
きる効果が得られる。 The present invention provides an amplifier into which a signal is input from a signal source via an emitter follower circuit, and a phase circuit having an input terminal connected to the output terminal of the amplifier and an output terminal connected to a collector terminal of a transistor constituting the emitter follower circuit. and an output signal is obtained from the output terminal of the amplifier by setting the transfer function of the phase circuit to be the reciprocal of the transfer function of the amplifier, and is characterized in that the frequency band is not limited by the signal source impedance. Therefore, the effect of amplification that effectively utilizes the original cutoff frequency of the amplifier can be obtained.
以下、本発明の一実施例を第３図〜第５図に基
づいて説明する。なお、第１図ならびに第２図と
同様のものには同一符号を付けてその説明を省
く。 Hereinafter, one embodiment of the present invention will be described based on FIGS. 3 to 5. Components similar to those in FIG. 1 and FIG. 2 are given the same reference numerals and their explanations will be omitted.
６は位相回路で、入力端子７が増幅器４の出力
に接続され、出力端子８がトランジスタ３のコレ
クタに接続されており、増幅器４の伝達関数をA〓
とし位相回路６の伝達関数をB〓とした時、この位
相回路６の伝達関数B〓は、B〓＝１／A〓に設定され
ている。 6 is a phase circuit, the input terminal 7 is connected to the output of the amplifier 4, the output terminal 8 is connected to the collector of the transistor 3, and the transfer function of the amplifier 4 is expressed as A〓
Assuming that the transfer function of the phase circuit 6 is B〓, the transfer function B〓 of this phase circuit 6 is set as B〓=1/A〓.
第４図は第３図の等価回路を示し、これによつ
てB〓＝１／A〓の理由を説明する。 FIG. 4 shows an equivalent circuit of FIG. 3, and explains the reason for B=1/A.
ここで、信号源５の出力電圧をEi、増幅回路の
入力電圧をei、増幅回路の出力電圧をEp、位相回
路６の出力電圧をepとして、伝達特性（Eo／Ei）
を求
増幅器４の入出力特性より、
ei・A〓＝Ep ……
位相回路６の入出力特性より、
Ep・B〓＝ep ……
また、増幅器４の入力インピーダンスが高いも
のとすると、
Ei−（ei−ep）・jωCpb・RG＝ei ……
となり、伝達特性（Eo／Ei）は次式で表わせる。 Here, assuming that the output voltage of the signal source 5 is Ei, the input voltage of the amplifier circuit is e i , the output voltage of the amplifier circuit is E p , and the output voltage of the phase circuit 6 is e p , the transfer characteristic (Eo/Ei)
From the input/output characteristics of the amplifier 4, e i・A〓=E p ... From the input/output characteristics of the phase circuit 6, E p・B〓=e p ... Also, assuming that the input impedance of the amplifier 4 is high, Then, E i −(e i −e p )・jωC pb・R G = e i ..., and the transfer characteristic (Eo/Ei) can be expressed by the following equation.
（Eo／Ei）＝Ａ／・／１＋Ｓ・Cpb・RG（１−Ａ・Ｂ）
……
但し、Ｓ＝2jπf
この５式はA〓が周波数特性を持たなくとも
（Eo／Ei）が周波数特性を持つことを示している
が、
ここで、
１−A〓・B〓＝０ ……
すなわち、
B〓＝１／A〓 ……
となるように位相回路６の伝達関数B〓を選ぶと、
（Eo／Ei）＝A〓 ……
となり、信号源インピーダンスRGおよび容量Cpb
の値は（Eo／Ei）と無関係となり、増幅回路の
帯域は増幅器４のそれと同じになる。従つて、信
号源インピーダンスRGが高く、このRGと容量Cpb
により決まる遮断周波数が低い従来のものと比べ
て遮断周波数を高くすることができる。(Eo/Ei)=A/・/1+S・C pb・R G (1−A・B) ... However, S=2jπf This formula 5 shows that even if A〓 does not have frequency characteristics, (Eo/Ei) This shows that it has a frequency characteristic, but here, select the transfer function B of the phase circuit 6 so that 1-A〓・B〓=0... In other words, B〓=1/A〓... Then, (Eo/Ei)=A〓..., and the signal source impedance R G and capacitance C pb
The value of is independent of (Eo/Ei), and the band of the amplifier circuit becomes the same as that of the amplifier 4. Therefore, the signal source impedance R G is high, and this R G and the capacitance C pb
The cut-off frequency can be made higher than that of the conventional system, which has a low cut-off frequency determined by
通常、増幅器４の伝達関数A〓は、遮断時定数を
τとすると、
A〓＝Ａ／１＋Ｓ・τ ……
（但し、Ｓ＝jω）
と表わすことができ、位相回路６の伝達関数B〓
を、
B〓＝１／Ａ＝１＋Ｓ・τ／Ａ ……
に設定すれば目的を達成できる。 Normally, the transfer function A〓 of the amplifier 4 can be expressed as A〓=A/1+S・τ (where S=jω), where the cutoff time constant is τ, and the transfer function B〓 of the phase circuit 6
The purpose can be achieved by setting B=1/A=1+S・τ/A...
第５図は増幅器４が反転増幅器で構成した場合
の前記位相回路６の具体例を示す。ベースが入力
端子となるトランジスタ９のエミツタと基準電位
としての接地間には、エミツタ抵抗R1とピーキ
ング用コンデンサC1とを並列接続して成る帰還
回路１０が介装されている。R2は前記トランジ
スタ９のコレクタと電源との間に介装された負荷
抵抗で、この負荷抵抗R2とコレクタとの接続点
から信号が出力される。このように構成された位
相回路６の伝達関数B〓は、
B〓＝１＋Ｓ・C1・R1／−R1／R2 ……
と表わすことができ、
−R1／R2＝Ａ ……
C1・R1＝τ ……
と定数を選ぶことにより前記第10式が満足され
る。 FIG. 5 shows a specific example of the phase circuit 6 in the case where the amplifier 4 is constituted by an inverting amplifier. A feedback circuit 10 comprising an emitter resistor R 1 and a peaking capacitor C 1 connected in parallel is interposed between the emitter of the transistor 9 whose base is an input terminal and the ground serving as a reference potential. R 2 is a load resistor interposed between the collector of the transistor 9 and the power supply, and a signal is output from the connection point between the load resistor R 2 and the collector. The transfer function B〓 of the phase circuit 6 configured in this way can be expressed as B〓=1+S・C 1・R 1 /−R 1 /R 2 ..., and −R 1 /R 2 =A ... ...C 1 · R 1 = τ ... By selecting a constant, the above-mentioned formula 10 is satisfied.
以上説明のように本発明の増幅回路によると、
遮断周波数は信号源インピーダンスと入力容量の
関数でなくなるため、高い信号源インピーダンス
の信号源に増幅回路を接続した場合に、入力段の
トランジスタの出力容量により帯域の制限を受け
ることがなく、増幅器本来の遮断周波数まで使用
できる。従つて、高い信号源インピーダンスの信
号を増幅する場合に、高周波特性の良好な増幅を
実施できるものである。 As explained above, according to the amplifier circuit of the present invention,
Since the cutoff frequency is no longer a function of the signal source impedance and input capacitance, when an amplifier circuit is connected to a signal source with high signal source impedance, the band is not limited by the output capacitance of the transistor in the input stage, and the amplifier Can be used up to the cutoff frequency of Therefore, when amplifying a signal with a high signal source impedance, it is possible to perform amplification with good high frequency characteristics.
第１図は従来のエミツタフオロア回路付増幅回
路の構成図、第２図は信号源の等価回路、第３図
は本発明による増幅回路の一実施例の構成図、第
４図は第３図の等価回路図、第５図は位相回路の
具体構成図である。
１……入力端子、２……出力端子、３……トラ
ンジスタ、４……増幅器、６……位相回路、A〓…
…増幅器の伝達関数、B〓……位相回路の伝達関
数。
FIG. 1 is a block diagram of a conventional amplifier circuit with an emitter follower circuit, FIG. 2 is an equivalent circuit of a signal source, FIG. 3 is a block diagram of an embodiment of an amplifier circuit according to the present invention, and FIG. The equivalent circuit diagram, FIG. 5, is a concrete configuration diagram of the phase circuit. 1...Input terminal, 2...Output terminal, 3...Transistor, 4...Amplifier, 6...Phase circuit, A〓...
…transfer function of amplifier, B〓…transfer function of phase circuit.
Claims (1)
号が入力される増幅器と、この増幅器の出力端子
に入力端子が接続され出力端子が前記エミツタフ
オロア回路を構成するトランジスタのコレクタ端
子に接続された位相回路とを設け、前記位相回路
の伝達関数を前記増幅器の伝達関数の逆数に設定
して前記増幅器の出力端子から出力信号を得る増
幅回路。 ２ 増幅器を、反転増幅器とし、かつ位相回路
を、ベースに信号が入力されエミツタと基準電位
との間に抵抗と容量とを並列接続して成る帰還回
路が介装されコレクタと負荷抵抗との接続点から
信号を出力するよう構成し、前記帰還回路の時定
数を位相回路の伝達関数が前記増幅器の伝達関数
の逆数となるように設定したことを特徴とする特
許請求の範囲第１項記載の増幅回路。[Claims] 1. An amplifier into which a signal is input from a signal source via an emitter follower circuit, an input terminal connected to the output terminal of this amplifier, and an output terminal connected to a collector terminal of a transistor constituting the emitter follower circuit. and a phase circuit, the transfer function of the phase circuit being set to the reciprocal of the transfer function of the amplifier to obtain an output signal from the output terminal of the amplifier. 2 The amplifier is an inverting amplifier, and the phase circuit is connected to the collector and the load resistor by interposing a feedback circuit in which a signal is input to the base and a resistor and a capacitor are connected in parallel between the emitter and the reference potential. Claim 1, characterized in that the feedback circuit is configured to output a signal from a point, and the time constant of the feedback circuit is set such that the transfer function of the phase circuit is a reciprocal of the transfer function of the amplifier. Amplification circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10822182A JPS58223905A (en) | 1982-06-22 | 1982-06-22 | Amplifier circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10822182A JPS58223905A (en) | 1982-06-22 | 1982-06-22 | Amplifier circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS58223905A JPS58223905A (en) | 1983-12-26 |
| JPH0131328B2 true JPH0131328B2 (en) | 1989-06-26 |
Family
ID=14479105
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10822182A Granted JPS58223905A (en) | 1982-06-22 | 1982-06-22 | Amplifier circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS58223905A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6306343B2 (en) * | 2013-12-25 | 2018-04-04 | 株式会社半導体エネルギー研究所 | Source follower |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5193147A (en) * | 1975-02-12 | 1976-08-16 | ||
| JPS51107054A (en) * | 1975-02-12 | 1976-09-22 | Siemens Ag | KORYUDENATSUZOFUKUKI |
| JPS537159A (en) * | 1976-07-09 | 1978-01-23 | Toshiba Corp | Transistor amplifier |
-
1982
- 1982-06-22 JP JP10822182A patent/JPS58223905A/en active Granted
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5193147A (en) * | 1975-02-12 | 1976-08-16 | ||
| JPS51107054A (en) * | 1975-02-12 | 1976-09-22 | Siemens Ag | KORYUDENATSUZOFUKUKI |
| JPS537159A (en) * | 1976-07-09 | 1978-01-23 | Toshiba Corp | Transistor amplifier |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS58223905A (en) | 1983-12-26 |
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