JPH06291562A - Power amplifier - Google Patents
Power amplifierInfo
- Publication number
- JPH06291562A JPH06291562A JP5096880A JP9688093A JPH06291562A JP H06291562 A JPH06291562 A JP H06291562A JP 5096880 A JP5096880 A JP 5096880A JP 9688093 A JP9688093 A JP 9688093A JP H06291562 A JPH06291562 A JP H06291562A
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- signal
- circuit
- feedback
- amplifier
- output signal
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は電力増幅器に関し、例え
ばスピーカの駆動回路に適用して好適なものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power amplifier, and is preferably applied to, for example, a speaker driving circuit.
【０００２】[0002]
【従来の技術】従来、音響機器の増幅器においては、周
波数特性を向上させるため出力信号を入力段に負帰還す
る帰還増幅器が多く用いられている。この帰還増幅器
は、出力信号と入力信号とを比較し、その差分を増幅す
るようになされている。2. Description of the Related Art Conventionally, in an amplifier of an audio device, a feedback amplifier which negatively feeds back an output signal to an input stage is often used in order to improve frequency characteristics. This feedback amplifier compares the output signal with the input signal and amplifies the difference.
【０００３】[0003]
【発明が解決しようとする課題】ところで、この種の帰
還増幅器をスピーカの駆動回路として用いる場合、帰還
増幅器は出力信号として正逆の電流をボイスコイルに与
え、スピーカを前後に駆動している。ところがボイスコ
イルにはスピーカのコーンが押し出し又は引き込まれた
後、ダンパーによつて通常位置へ戻ろうとする際にフレ
ミング右手の法則による逆起電力が発生し、この逆起電
力が帰還回路を介して初段へ戻されていた。従つて増幅
器自身の帰還信号にこの逆起電力が重畳され、本来の出
力信号と入力信号との差分を増幅できなかつた。これに
より本来の帰還回路がスピーカの影響を受ける問題があ
つた。By the way, when this type of feedback amplifier is used as a speaker driving circuit, the feedback amplifier applies forward and reverse currents as output signals to the voice coil to drive the speaker back and forth. However, after the speaker cone is pushed out or pulled into the voice coil, a counter electromotive force is generated by the Fleming's right-hand rule when trying to return to the normal position by the damper, and this counter electromotive force is generated via the feedback circuit. It was returned to the first stage. Therefore, this counter electromotive force was superimposed on the feedback signal of the amplifier itself, and the difference between the original output signal and the input signal could not be amplified. This causes a problem that the original feedback circuit is affected by the speaker.
【０００４】本発明は以上の点を考慮してなされたもの
で、負荷に発生する逆起電力の影響を受けることなく出
力信号の周波数特性を一段と向上することができる電力
増幅器を提案しようとするものである。The present invention has been made in consideration of the above points, and proposes a power amplifier capable of further improving the frequency characteristic of an output signal without being affected by a back electromotive force generated in a load. It is a thing.
【０００５】[0005]
【課題を解決するための手段】かかる課題を解決するた
め本発明においては、入力信号Ｓ１を増幅し、第１の出
力信号Ｓ２として出力し、出力端に接続された負荷５を
駆動する第１の増幅回路２と、第１の増幅回路２と同電
気特性でなり、かつ、入力信号Ｓ１を増幅し、第２の出
力信号Ｓ３として出力する第２の増幅回路３と、第２の
出力信号Ｓ３を第１及び第２の増幅回路２及び３の入力
端に負帰還する帰還回路６とを設けるようにする。In order to solve such a problem, in the present invention, a first signal for amplifying an input signal S1 and outputting it as a first output signal S2 for driving a load 5 connected to an output terminal is provided. Second amplification circuit 2, which has the same electrical characteristics as those of the first amplification circuit 2, and which amplifies the input signal S1 and outputs it as the second output signal S3, and the second output signal A feedback circuit 6 for negatively feeding back S3 to the input ends of the first and second amplifier circuits 2 and 3 is provided.
【０００６】[0006]
【作用】同電気特性を有する第１及び第２の増幅回路２
及び３に入力信号Ｓ１を並列に入力することとし、負荷
５が接続されていない第２の増幅回路３より出力される
第２の出力信号Ｓ３を第１及び第２の増幅回路２及び３
に負帰還する。これにより負荷５を駆動する第１の増幅
回路２の入力端には負荷５に発生する逆起電力を含まな
い本来の出力信号が帰還されることができる。この結
果、従来逆起電力の影響によつて励化していた増幅後の
周波数特性を一段と向上させることができる。Operation: First and second amplifier circuits 2 having the same electrical characteristics
And 3 to input the input signal S1 in parallel, and to output the second output signal S3 output from the second amplifier circuit 3 to which the load 5 is not connected, to the first and second amplifier circuits 2 and 3.
Negative feedback to. As a result, the original output signal that does not include the back electromotive force generated in the load 5 can be fed back to the input terminal of the first amplifier circuit 2 that drives the load 5. As a result, it is possible to further improve the frequency characteristic after amplification, which has been conventionally excited by the influence of the back electromotive force.
【０００７】[0007]
【実施例】以下図面について、本発明の一実施例を詳述
する。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.
【０００８】図１において、１は全体としてスピーカ駆
動回路を示し、同等の電気特性を有する演算増幅器２及
び３の非反転入力端に入力信号Ｓ１をそれぞれ入力する
ようになされている。演算増幅器２は抵抗Ｒ１及びＲ２
でなる直列回路４及びこれと並列に接続されたスピーカ
５に出力信号Ｓ２を与える。In FIG. 1, reference numeral 1 denotes a speaker drive circuit as a whole, and an input signal S1 is input to the non-inverting input terminals of operational amplifiers 2 and 3 having equivalent electrical characteristics. The operational amplifier 2 has resistors R1 and R2.
The output signal S2 is given to the series circuit 4 and the speaker 5 connected in parallel.
【０００９】また演算増幅器３は出力信号Ｓ２と同等の
出力信号Ｓ３を帰還回路６に与え、これにより得られた
帰還信号Ｓ４を演算増幅器２及び３の反転入力端に与え
るようになされている。これにより演算増幅器３及び帰
還回路６は演算増幅器２及び直列回路４のダミー回路と
なり、直列回路４を介して帰還される帰還信号に代え
て、スピーカ５に発生する逆起電力の影響を受けない帰
還信号Ｓ４を演算増幅器２及び３に与えるようになされ
ている。Further, the operational amplifier 3 supplies an output signal S3 equivalent to the output signal S2 to the feedback circuit 6, and the feedback signal S4 thus obtained is supplied to the inverting input terminals of the operational amplifiers 2 and 3. As a result, the operational amplifier 3 and the feedback circuit 6 become dummy circuits of the operational amplifier 2 and the series circuit 4, and instead of the feedback signal fed back through the series circuit 4, there is no influence of the counter electromotive force generated in the speaker 5. The feedback signal S4 is applied to the operational amplifiers 2 and 3.
【００１０】ここで演算増幅器２及び３はそれぞれ図２
に示すように構成されている。Here, the operational amplifiers 2 and 3 are respectively shown in FIG.
It is configured as shown in.
【００１１】演算増幅器２の初段２Ａは電界効果トラン
ジスタＱ１及びＱ２の差動対によつてなる差動増幅回路
でなる。トランジスタＱ１及びＱ２のドレインには抵抗
Ｒ３及びＲ４を介して電源電圧＋Ｖ1 が与えられ、共通
ソースには電流源７を介して電源電圧−Ｖ1 が与えられ
ている。電界効果トランジスタＱ１のゲートには入力端
子Ｐ１が接続され、抵抗Ｒ５を介して流れる入力信号Ｓ
１によつて発生された電圧が与えられており、ドレイン
より電圧増幅段２Ｂの電圧増幅回路８に入力信号Ｓ１を
増幅した出力信号Ｓ５を与えている。The first stage 2A of the operational amplifier 2 is a differential amplifier circuit formed by a differential pair of field effect transistors Q1 and Q2. The power supply voltage + V 1 is applied to the drains of the transistors Q1 and Q2 via the resistors R3 and R4, and the power supply voltage −V 1 is applied to the common source via the current source 7. The input terminal P1 is connected to the gate of the field effect transistor Q1 and the input signal S flowing through the resistor R5.
The voltage generated by 1 is given, and the output signal S5 obtained by amplifying the input signal S1 is given from the drain to the voltage amplification circuit 8 of the voltage amplification stage 2B.
【００１２】同様に演算増幅器３の初段３Ａはトランジ
スタＱ３及びＱ４の差動対によつてなる差動増幅回路で
なり、入力信号Ｓ１を増幅し、ドレインより電圧増幅段
３Ｂの電圧増幅回路１０に出力信号Ｓ５を与えている。Similarly, the first stage 3A of the operational amplifier 3 is a differential amplifier circuit composed of a differential pair of transistors Q3 and Q4, which amplifies the input signal S1 and outputs it from the drain to the voltage amplifier circuit 10 of the voltage amplifier stage 3B. The output signal S5 is given.
【００１３】同じ回路構成でなる電圧増幅回路８及び１
０は２つの出力端を有し、この２つの出力端が電流増幅
段２Ｃ及び３ＣのトランジスタＱ５、Ｑ６及びＱ７、Ｑ
８のベースにそれぞれ接続されている。これにより電圧
増幅回路８及び１０は出力信号Ｓ５の電圧を増幅した出
力信号Ｓ６を電流増幅段２Ｃ及び３Ｃに与える。Voltage amplifier circuits 8 and 1 having the same circuit configuration
0 has two outputs, which are the transistors Q5, Q6 and Q7, Q of the current amplification stages 2C and 3C.
8 bases are connected respectively. As a result, the voltage amplification circuits 8 and 10 give the output signal S6 obtained by amplifying the voltage of the output signal S5 to the current amplification stages 2C and 3C.
【００１４】電流増幅段２Ｃ及び３ＣはトランジスタＱ
５、Ｑ６及びＱ７及びＱ８のコンプリメンタリ型シング
ルエンデツドプツシユプル回路によつて構成されてい
る。ここで各エミツタ間には抵抗Ｒ８、Ｒ９及びＲ１
０、Ｒ１１がそれぞれ接続され、出力信号Ｓ６を電流増
幅した出力信号Ｓ２及びＳ３が、抵抗Ｒ８、Ｒ９及びＲ
１０、Ｒ１１の接続中点より出力される。The current amplification stages 2C and 3C include a transistor Q.
5, Q6, Q7, and Q8 complementary type single-ended push-pull circuits. Here, resistors R8, R9 and R1 are provided between the emitters.
0 and R11 are respectively connected, and output signals S2 and S3 obtained by current-amplifying the output signal S6 are connected to resistors R8, R9 and R
It is output from the midpoint of connection of 10 and R11.
【００１５】帰還回路６は演算増幅器２とスピーカ５の
中点に接続されている帰還回路４と同様、抵抗Ｒ１２及
びＲ１３の直列回路でなり、その接続中点を介して電界
効果トランジスタＱ２及びＱ４のゲートに帰還信号Ｓ４
を帰還している。因みに抵抗Ｒ１２の値は抵抗Ｒ１の値
と同一であり、抵抗Ｒ１３の値は抵抗Ｒ２の値と同一で
ある。また直列回路４及び帰還回路６のインピーダンス
はスピーカのインピーダンスに比して十分に大きく設定
されている。Like the feedback circuit 4 connected to the midpoint of the operational amplifier 2 and the speaker 5, the feedback circuit 6 is a series circuit of resistors R12 and R13, and the field effect transistors Q2 and Q4 are connected via the midpoint of the connection. Return signal S4 to the gate of
Are returning. Incidentally, the value of the resistor R12 is the same as the value of the resistor R1, and the value of the resistor R13 is the same as the value of the resistor R2. The impedances of the series circuit 4 and the feedback circuit 6 are set sufficiently higher than the impedance of the speaker.
【００１６】以上の構成において、入力端子Ｐ１に入力
信号Ｓ１が与えられると、入力信号Ｓ１は抵抗Ｒ５で電
圧変換されて演算増幅器２及び３に与えられる。演算増
幅器２は入力信号Ｓ１を電力増幅し、これにより得られ
る出力信号Ｓ２を直列回路４及びスピーカ５のみに与え
る。In the above configuration, when the input signal S1 is applied to the input terminal P1, the input signal S1 is voltage converted by the resistor R5 and applied to the operational amplifiers 2 and 3. The operational amplifier 2 power-amplifies the input signal S1 and supplies the output signal S2 obtained thereby to only the series circuit 4 and the speaker 5.
【００１７】スピーカ５は、出力信号Ｓ２によつてコー
ン部を前後に駆動され、音を再生する。このときコイル
には誘導成分Ｌによる逆起電力が発生するが、帰還経路
が設けられていないため演算増幅器２の初段に帰還され
ることはなく負帰還制御に全く影響を与えない。The speaker 5 drives the cone portion back and forth by the output signal S2 to reproduce sound. At this time, a counter electromotive force due to the inductive component L is generated in the coil, but since the feedback path is not provided, it is not fed back to the first stage of the operational amplifier 2 and has no influence on the negative feedback control.
【００１８】演算増幅器３は入力信号Ｓ１を電力増幅
し、これにより得られる出力信号Ｓ２と同一の出力信号
Ｓ３を帰還回路６に与える。これによつて帰還信号Ｓ４
は、出力信号Ｓ２を与えられた直列回路４より取り出す
場合の帰還信号と同一となると共に、逆起電力の成分が
ない。The operational amplifier 3 power-amplifies the input signal S1 and supplies the feedback circuit 6 with the same output signal S3 as the output signal S2 obtained thereby. As a result, the feedback signal S4
Is the same as the feedback signal when the output signal S2 is taken out from the given series circuit 4, and has no counter electromotive force component.
【００１９】これにより帰還信号Ｓ４が初段２Ａ及び３
Ａの電界効果トランジスタＱ２及びＱ４に与えられる
と、演算増幅器２及び３は出力信号Ｓ２及びＳ３が同一
となるように負帰還制御される。As a result, the feedback signal S4 is transmitted to the first stage 2A and 3
When applied to the field effect transistors Q2 and Q4 of A, the operational amplifiers 2 and 3 are negatively feedback controlled so that the output signals S2 and S3 are the same.
【００２０】以上の構成によれば、演算増幅器２におい
ては、スピーカ５の誘導成分Ｌによる逆起電力が初段２
Ａの反転入力端に帰還しないようにし、かつ演算増幅器
３においては、逆起電力の影響を受けない帰還信号Ｓ４
を初段２Ａの反転入力端に帰還させるようにしたことに
より出力信号Ｓ２の負帰還制御に対する逆起電力の影響
をなくせる。According to the above configuration, in the operational amplifier 2, the counter electromotive force due to the inductive component L of the speaker 5 is the first stage 2.
In the operational amplifier 3, the feedback signal S4 is set so as not to be fed back to the inverting input terminal of A and is not affected by the back electromotive force.
By feeding back to the inverting input terminal of the first stage 2A, the influence of the back electromotive force on the negative feedback control of the output signal S2 can be eliminated.
【００２１】なお上述の実施例においては、演算増幅器
２がスピーカ５を駆動する場合について述べたが、本発
明はこれに限らず、磁気記録再生装置の磁気ヘツド、モ
ータ、アクチエータ等のコイル素子を含み、かつ磁束を
横切るように駆動される負荷に出力信号を供給する増幅
器にも適用し得る。In the above embodiment, the case where the operational amplifier 2 drives the speaker 5 has been described, but the present invention is not limited to this, and coil elements such as a magnetic head, a motor and an actuator of a magnetic recording / reproducing apparatus are used. It may also be applied to an amplifier that provides an output signal to a load that includes and is driven across the magnetic flux.
【００２２】[0022]
【発明の効果】上述のように本発明によれば、負荷を駆
動する第１の増幅回路に対して並列に設けられた第２の
増幅回路によつて帰還回路を駆動し、これにより得た帰
還信号を第１及び第２の増幅回路の入力端に負帰還させ
ることによつて、負帰還の特性が負荷の逆起電力の影響
を受けず、また出力信号の歪みを減少させることができ
る電力増幅器を容易に実現することができる。As described above, according to the present invention, the feedback circuit is driven by the second amplifier circuit provided in parallel with the first amplifier circuit for driving the load, and the feedback circuit is obtained by this. By negatively feeding back the feedback signal to the input terminals of the first and second amplifier circuits, the characteristics of the negative feedback are not affected by the back electromotive force of the load, and the distortion of the output signal can be reduced. The power amplifier can be easily realized.
【図１】本発明による電力増幅器の一実施例を示す接続
図である。FIG. 1 is a connection diagram showing an embodiment of a power amplifier according to the present invention.
【図２】その等価回路を示す接続図である。FIG. 2 is a connection diagram showing an equivalent circuit thereof.
１……スピーカ駆動回路、２、３……演算増幅器、２
Ａ、３Ａ……初段、２Ｂ、３Ｂ……電圧増幅段、２Ｃ、
３Ｃ……電流増幅段、４……直列回路、５……スピー
カ、６……帰還回路、７、９……電流源、８、１０……
電圧増幅回路。1 ... Speaker drive circuit, 2,3 ... Operational amplifier, 2
A, 3A ... First stage, 2B, 3B ... Voltage amplification stage, 2C,
3C ... Current amplification stage, 4 ... Series circuit, 5 ... Speaker, 6 ... Feedback circuit, 7,9 ... Current source, 8,10 ...
Voltage amplifier circuit.
Claims (3)
出力し、出力端に接続された負荷を駆動する第１の増幅
回路と、 上記第１の増幅回路と同電気特性でなり、かつ、上記入
力信号を増幅し、第２の出力信号として出力する第２の
増幅回路と、 上記第２の出力信号を上記第１及び第２の増幅回路の入
力端に負帰還する帰還回路とを具えることを特徴とする
電力増幅器。1. A first amplifier circuit for amplifying an input signal, outputting the amplified signal as a first output signal, and driving a load connected to an output terminal, and having the same electrical characteristics as those of the first amplifier circuit, And a second amplifier circuit that amplifies the input signal and outputs it as a second output signal; and a feedback circuit that negatively feeds back the second output signal to the input ends of the first and second amplifier circuits. A power amplifier characterized by comprising:
とする請求項１に記載の電力増幅器。2. The power amplifier according to claim 1, wherein the load is a moving coil.
力信号及び第２の出力信号の差分を増幅して出力する差
動入力段と、 上記差動入力段より出力された差分信号を電圧増幅して
出力する電圧増幅段と、 上記電圧増幅段より出力された信号を入力し、電流増幅
して出力する電流増幅部とを有することを特徴とする請
求項１又は請求項２に記載の電力増幅器。3. A differential input for inputting the input signal and the second output signal, amplifying a difference between the input signal and the second output signal, and outputting the amplified differential signal. A voltage amplification stage that voltage-amplifies and outputs the differential signal output from the differential input stage, and a current amplification unit that inputs the signal output from the voltage amplification stage and current-amplifies and outputs the signal. The power amplifier according to claim 1 or 2, further comprising:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP09688093A JP3410146B2 (en) | 1993-03-31 | 1993-03-31 | Power amplifier |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP09688093A JP3410146B2 (en) | 1993-03-31 | 1993-03-31 | Power amplifier |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH06291562A true JPH06291562A (en) | 1994-10-18 |
| JP3410146B2 JP3410146B2 (en) | 2003-05-26 |
Family
ID=14176734
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP09688093A Expired - Fee Related JP3410146B2 (en) | 1993-03-31 | 1993-03-31 | Power amplifier |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3410146B2 (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH11174127A (en) * | 1997-12-09 | 1999-07-02 | Hitachi Electron Eng Co Ltd | Load-current output circuit to electronic device and ic tester |
| JPH11174128A (en) * | 1997-12-09 | 1999-07-02 | Hitachi Electron Eng Co Ltd | Load-current output circuit to electronic device and ic tester |
| JPH11195933A (en) * | 1997-12-27 | 1999-07-21 | Murata Mfg Co Ltd | Amplifier for speaker |
| JP2007325812A (en) * | 2006-06-09 | 2007-12-20 | Matsushita Electric Ind Co Ltd | Induction heating rice cooker |
| US7550999B2 (en) | 2005-08-15 | 2009-06-23 | Nec Electronics Corporation | Receiver capable of increasing operation speed with suppressing increase of power consumption |
| JP2016082520A (en) * | 2014-10-21 | 2016-05-16 | 邦男 中山 | Current drive circuit |
| JP2020014223A (en) * | 2014-10-21 | 2020-01-23 | 邦男 中山 | Current drive device |
-
1993
- 1993-03-31 JP JP09688093A patent/JP3410146B2/en not_active Expired - Fee Related
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH11174127A (en) * | 1997-12-09 | 1999-07-02 | Hitachi Electron Eng Co Ltd | Load-current output circuit to electronic device and ic tester |
| JPH11174128A (en) * | 1997-12-09 | 1999-07-02 | Hitachi Electron Eng Co Ltd | Load-current output circuit to electronic device and ic tester |
| JPH11195933A (en) * | 1997-12-27 | 1999-07-21 | Murata Mfg Co Ltd | Amplifier for speaker |
| US7550999B2 (en) | 2005-08-15 | 2009-06-23 | Nec Electronics Corporation | Receiver capable of increasing operation speed with suppressing increase of power consumption |
| JP2007325812A (en) * | 2006-06-09 | 2007-12-20 | Matsushita Electric Ind Co Ltd | Induction heating rice cooker |
| JP2016082520A (en) * | 2014-10-21 | 2016-05-16 | 邦男 中山 | Current drive circuit |
| JP2020014223A (en) * | 2014-10-21 | 2020-01-23 | 邦男 中山 | Current drive device |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3410146B2 (en) | 2003-05-26 |
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| LAPS | Cancellation because of no payment of annual fees |