JPS62276909A - Output switching circuit - Google Patents

Output switching circuit

Info

Publication number
JPS62276909A
JPS62276909A JP61120543A JP12054386A JPS62276909A JP S62276909 A JPS62276909 A JP S62276909A JP 61120543 A JP61120543 A JP 61120543A JP 12054386 A JP12054386 A JP 12054386A JP S62276909 A JPS62276909 A JP S62276909A
Authority
JP
Japan
Prior art keywords
output
power amplifier
headphone
speaker
input
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.)
Pending
Application number
JP61120543A
Other languages
Japanese (ja)
Inventor
Noboru Katagishi
片岸　昇
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Panasonic Holdings Corp
Original Assignee
Matsushita Electric Industrial Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Matsushita Electric Industrial Co Ltd filed Critical Matsushita Electric Industrial Co Ltd
Priority to JP61120543A priority Critical patent/JPS62276909A/en
Publication of JPS62276909A publication Critical patent/JPS62276909A/en
Pending legal-status Critical Current

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  • Control Of Amplification And Gain Control (AREA)
  • Amplifiers (AREA)
  • Circuit For Audible Band Transducer (AREA)

Abstract

PURPOSE:To set the output of a power amplifier suitable for the listening by a headphone automatically by changing the input impedance of the power amplifier as soon as the output of the power amplifier is switched. CONSTITUTION:An input signal of the power amplifier 3 is inputted via a sound volume 2 at the output from a speaker and its output signal is outputted from a switching transistor (TR) 10 from the speaker 7. In throwing a changeover switch 4 to the position HP, TRs 8, 9 are operated at the same time. Therefore the input signal of the anplifier 3 is reduced more than that at the speaker output because an input resistor 1 is added as a load. The output signal of the amplifier 3 is fed to a headphone output terminal 6 via the TR 9. Thus, in selecting the input resistor 1 properly at the output of the headphone, the output of the power amplifier suitable for the listening by the headphone is set automatically.

Description

【発明の詳細な説明】 ３、発明の詳細な説明 産業上の利用分野 本発明は、負荷としてのヘッドホンとスピーカが切換え
接続されるパワーアンプにおける出力切換回路に関する
ものである。Detailed Description of the Invention 3. Detailed Description of the Invention Field of Industrial Application The present invention relates to an output switching circuit in a power amplifier to which headphones and speakers as loads are switched and connected.

従来の技術 従来、ヘッドホンとスピーカに兼用のパワーアンプにお
ける出力切換えは、パワーアンプの出力側で切換えてい
た。BACKGROUND OF THE INVENTION Conventionally, output switching in power amplifiers used for both headphones and speakers was performed on the output side of the power amplifier.

以下、図面全参照しながら従来の出力切換回路について
第２図を参照して説明する。第２図において、パワーア
ンプ３への入力信号ｉは入力抵抗１と音量ボリウム２を
経て入力され、出力信号は出力切換スイッチ４の共通端
子に供給され、この出力切換スイッチ４を切換えること
によってスピーカ７あるいは出力調整抵抗Ｓを介してヘ
ッドホンが接続される端子６に供給される。Hereinafter, a conventional output switching circuit will be explained with reference to FIG. 2 while referring to all the drawings. In FIG. 2, an input signal i to a power amplifier 3 is inputted via an input resistor 1 and a volume adjuster 2, and an output signal is supplied to a common terminal of an output selector switch 4. By switching this output selector switch 4, a speaker 7 or via an output adjustment resistor S to a terminal 6 to which headphones are connected.

発明が解決しようとする問題点 しかしながら、上記のような構成では、小型音響機器の
場合釦スピーカ７は小口径のものとなり、出力自体も小
さいため、スピーカ７の鳴シヲ十分確保するようにパワ
ーアンプ３のゲインを設定すると、パワーアンプ３自体
がクリップしてしまい、所定の音量ボリウム２の位置の
ままで出力切換スイッチ４をヘッドホン側に切換えた場
合、ヘッドホン出力がクリップしてしまっているために
ヘッドホン受聴に悪影響を与え、音量ボリウム２を調整
して使用しなければならない。つまシスピー力とヘッド
ホンを切換える時は音量ボリウム２ｔ−必ず調整しなけ
ればならないという操作性の面で問題があった。Problems to be Solved by the Invention However, in the above configuration, in the case of a small audio device, the button speaker 7 has a small diameter and the output itself is small, so a power amplifier is required to ensure sufficient sound quality from the speaker 7. If you set a gain of 3, the power amplifier 3 itself will clip, and if you switch the output selector switch 4 to the headphone side with the volume volume 2 at the specified position, the headphone output will clip. This has a negative effect on headphone listening, and the volume volume 2 must be adjusted before use. There was a problem in terms of operability, as the volume volume had to be adjusted to 2T when switching between the speaker system and the headphones.

問題点を解決するための手段 上記問題点全解決するには本発明の出力切換回路は、パ
ワーアンプの出力側に接続されるスピーカとヘッドホン
の切換手段に応動する切換手段によって上記パワーアン
プの入力インピーダンスを変えるようにし几ことを特徴
とするものである。Means for Solving the Problems To solve all of the above problems, the output switching circuit of the present invention switches the input of the power amplifier by a switching means responsive to switching means for speakers and headphones connected to the output side of the power amplifier. The feature is that the impedance is changed.

作　　用 本発明は上記した構成によって、パワーアンプの出力切
換えに応動してパワーアンプの入力インピーダンスを切
換えることによりヘッドホン受聴に適し之パワーアンプ
の出力を自動的に設定することができることとなり、音
量ボリウムの定位置でも好適なヘッドホン受聴を実現す
ることができるものである。According to the above-described configuration, the present invention can automatically set the output of the power amplifier suitable for headphone listening by switching the input impedance of the power amplifier in response to switching the output of the power amplifier. It is possible to realize suitable headphone listening even in a fixed position.

実施例 以下、本発明の一実施例を第１図にて説明する。Example An embodiment of the present invention will be described below with reference to FIG.

第１図において、まず、パワーアンプ３の入力信号ｉは
、スピーカ出力時は音量ボリウム２を経て入力され、出
力信号はスピーカ７からスピーカ出カスイツチングトラ
ンジスタ１ｏを経て出力される。第２図はスピーカ出力
時を示す。次に出力切換スイッチ４をヘッドホン出力側
に切換えると、入力抵抗スイッチングトランジスタ８と
へソドホン出カスイツチングトランジスタ９が同時に動
作する。パワーアンプ３の入力信号は入力抵抗１が負荷
として付加されるので、スピーカ出力時より減少する。In FIG. 1, first, the input signal i of the power amplifier 3 is inputted via the volume control 2 when outputting from the speaker, and the output signal is outputted from the speaker 7 via the speaker output switching transistor 1o. FIG. 2 shows the output from the speaker. Next, when the output selector switch 4 is switched to the headphone output side, the input resistance switching transistor 8 and the hesophone output switching transistor 9 operate simultaneously. Since the input resistor 1 is added as a load to the input signal of the power amplifier 3, the input signal is reduced compared to when the signal is output from the speaker.

パワーアンプ３の出力信号はヘッドホン出力スイッチン
グトランジスタ９を経てヘッドホン出力端子６に供給さ
れる。つまり、パワーアンプ３のゲインをスピーカ出力
で十分に確保し、ヘッドホン出力時には入力抵抗１の値
を任意に設定することによってヘッドホン時の出力を調
整することが出来るので、音量ボリウム２の定位置での
ヘッドホン受聴が可能となる。The output signal of the power amplifier 3 is supplied to the headphone output terminal 6 via the headphone output switching transistor 9. In other words, by ensuring sufficient gain for the power amplifier 3 at the speaker output, and by arbitrarily setting the value of the input resistor 1 when outputting to headphones, the output when using headphones can be adjusted. can be listened to with headphones.

発明の効果 以上の様に本発明によれば、パワーアンプの出力切換え
を行なった際にその出力切換えと同時にパワーアンプの
入力インピーダンスを変化させることによって、ヘッド
ホン受聴に適したパワーアンプの出力を自動的に設定す
ることができ、もって、音量ボリウムの定位置でも好適
なヘッドホン受聴全実現することができるものである。Effects of the Invention As described above, according to the present invention, when the output of the power amplifier is changed, the input impedance of the power amplifier is changed at the same time as the output is changed, thereby automatically adjusting the output of the power amplifier suitable for headphone listening. Therefore, it is possible to achieve suitable headphone listening even with the volume control in a fixed position.

【図面の簡単な説明】[Brief explanation of drawings]

第１図は本発明の実施例における出力切換回路のブロッ
ク図、第２図は従来の出力切換回路のブロック図である
。 １・・・・人力抵抗、２・・・・・・音量ボリウム、３
・・・・・・パワーアンプ、４・・・・・・出力切換ス
イッチ、６・・・・・・ヘッドホン出力端子、７・・・
・・・スピーカ、８，９゜１０・・・・・・スイッチン
グトランジスタ。 代理人の氏名　弁理士　中　尾　敏　男　ほか１名第　
２　図FIG. 1 is a block diagram of an output switching circuit according to an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional output switching circuit. 1...Human resistance, 2...Volume volume, 3
...Power amplifier, 4...Output selector switch, 6...Headphone output terminal, 7...
...Speaker, 8,9°10...Switching transistor. Name of agent: Patent attorney Toshio Nakao and 1 other person
2 figure

Claims (1)

【特許請求の範囲】[Claims] パワーアンプの出力側に接続されるヘッドホンとスピー
カの第１切換手段と、この第１切換手段に応動して上記
パワーアンプの入力インピーダンスを切換える第２切換
手段を備えてなる出力切換回路。An output switching circuit comprising: first switching means for headphones and speakers connected to the output side of a power amplifier; and second switching means for switching input impedance of the power amplifier in response to the first switching means.
JP61120543A 1986-05-26 1986-05-26 Output switching circuit Pending JPS62276909A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP61120543A JPS62276909A (en) 1986-05-26 1986-05-26 Output switching circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP61120543A JPS62276909A (en) 1986-05-26 1986-05-26 Output switching circuit

Publications (1)

Publication Number Publication Date
JPS62276909A true JPS62276909A (en) 1987-12-01

Family

ID=14788898

Family Applications (1)

Application Number Title Priority Date Filing Date
JP61120543A Pending JPS62276909A (en) 1986-05-26 1986-05-26 Output switching circuit

Country Status (1)

Country Link
JP (1) JPS62276909A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04116426U (en) * 1991-03-28 1992-10-19 太陽誘電株式会社 signal attenuation circuit
JP2017069925A (en) * 2015-10-02 2017-04-06 レノボ・シンガポール・プライベート・リミテッド Voice reproduction device, voice reproduction method, and computer-executable program
CN106954137A (en) * 2017-01-04 2017-07-14 上海傅硅电子科技有限公司 A kind of double mode drive device for loudspeaker

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04116426U (en) * 1991-03-28 1992-10-19 太陽誘電株式会社 signal attenuation circuit
JP2017069925A (en) * 2015-10-02 2017-04-06 レノボ・シンガポール・プライベート・リミテッド Voice reproduction device, voice reproduction method, and computer-executable program
CN106954137A (en) * 2017-01-04 2017-07-14 上海傅硅电子科技有限公司 A kind of double mode drive device for loudspeaker

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