CN2744068Y

CN2744068Y - Preceding stage audio amplifier

Info

Publication number: CN2744068Y
Application number: CN 200420091887
Authority: CN
Inventors: 郝晋青
Original assignee: Taiyuan Normal University
Current assignee: Taiyuan Normal University
Priority date: 2004-09-30
Filing date: 2004-09-30
Publication date: 2005-11-30
Anticipated expiration: 2014-09-30

Abstract

The utility model relates to a preceding stage audio amplifier. The circuit comprises a shell and an internal circuit, wherein the internal circuit comprises an integrated amplification chip, and a lead-out wire connected with an inverted input end of the integrated amplification chip is arranged on the shell. The feedback signal may be introduced through the lead-out. The pre-stage audio amplifier is integrated independently, and the feedback signal of the pre-stage audio amplifier can be acquired from a post-stage amplifier or other feedback signal sources just due to the existence of the outgoing line connected with the inverting input end of the amplifying chip. A feedback capacitor is connected in series with the lead-out wire in the shell. The pre-stage audio amplifier is provided with a special feedback signal lead terminal, so that the pre-stage audio amplifier is independent and integrated, and the feedback signal can be acquired from a post-stage amplifier or other feedback signal sources. The front-stage audio amplifier enriches the structural form of the audio amplifier and is suitable for application occasions with special requirements.

Description

pre-amplifier

技术领域technical field

本实用新型涉及音频放大器，具体为一种前级音频放大器。The utility model relates to an audio amplifier, in particular to a pre-stage audio amplifier.

背景技术Background technique

现有的单级音频放大器，其反馈信号都来源于本级放大芯片的输出端；而反馈信号来源于后级放大器或其它的反馈信号源的音频放大器(或音频放大电路)，往往又与后级的其它放大器(或放大电路)或产生反馈信号源的电路连成一体，构成多级的音频放大器、频放大模块或者综合的功能电路模块。而在实际使用中，有时需要一种单独的前级放大器，需要其反馈信号采自后级放大器或其它的反馈信号源，而其又不与后级放大器或产生反馈信号源的电路构成一体。而现有产品中没有满足这种条件的可单独使用的前级放大器。Existing single-stage audio amplifier, its feedback signal all originates from the output end of this stage amplifier chip; And the audio amplifier (or audio frequency amplifying circuit) that feedback signal originates from rear stage amplifier or other feedback signal sources, often with rear Other amplifiers (or amplifying circuits) of the same stage or circuits that generate feedback signal sources are connected together to form a multi-stage audio amplifier, frequency amplification module or a comprehensive functional circuit module. However, in actual use, sometimes a separate pre-amplifier is needed, and its feedback signal needs to be collected from the post-stage amplifier or other feedback signal sources, and it is not integrated with the post-stage amplifier or the circuit that generates the feedback signal source. However, there is no pre-amplifier that can be used independently that meets this condition in existing products.

发明内容Contents of the invention

本实用新型解决现有技术没有反馈信号采自后级放大器或其它的反馈信号源、而又自成一体的单独的前级音频放大器的问题，提供一种这样的前级音频放大器。The utility model solves the problem in the prior art that there is no independent pre-stage audio amplifier whose feedback signal is collected from a rear-stage amplifier or other feedback signal sources, and is self-contained, and provides such a pre-stage audio amplifier.

本实用新型是采用如下技术方案实现的：前级音频放大器，包含壳体和内部电路，内部电路包含集成放大芯片，在壳体上有与集成放大芯片的反相输入端相连的引出线。该前级音频放大器单独自成一体，同时正是由于与放大芯片反相输入端相连的引出线的存在，使该前级放大器的反馈信号采自后级放大器或其它的反馈信号源成为可能。The utility model is realized by adopting the following technical scheme: the pre-stage audio amplifier includes a shell and an internal circuit, the internal circuit includes an integrated amplifier chip, and there is a lead wire connected to the inverting input end of the integrated amplifier chip on the shell. The pre-stage audio amplifier is independent and self-contained. At the same time, it is possible to collect the feedback signal of the pre-amplifier from the post-stage amplifier or other feedback signal sources just because of the existence of the lead wire connected to the inverting input terminal of the amplifier chip.

本实用新型所述的前级音频放大器设置了专门的反馈信号引线端，使该前级音频放大器既单独自成一体，又能使反馈信号采自后级放大器或其它的反馈信号源。该前级音频放大器丰富了音频放大器的结构形式，适用于有特殊要求的应用场合。The pre-stage audio amplifier described in the utility model is provided with a special feedback signal lead terminal, so that the pre-stage audio amplifier is independent and self-contained, and the feedback signal can be collected from the post-stage amplifier or other feedback signal sources. The pre-stage audio amplifier enriches the structural form of the audio amplifier and is suitable for applications with special requirements.

附图说明Description of drawings

图1为本实用新型所述前级音频放大器的壳体外观结构示意图；Fig. 1 is a schematic diagram of the shell appearance structure of the pre-stage audio amplifier described in the present invention;

图2为内部电路原理图；Figure 2 is a schematic diagram of the internal circuit;

图3为另一种结构的内部电路原理图；Fig. 3 is the internal circuit schematic diagram of another kind of structure;

具体实施方式Detailed ways

前级音频放大器，包含壳体1和内部电路，内部电路包含集成放大芯片G，在壳体上有与集成放大芯片的反相输入端相连的引出线2。该前级音频放大器所需的反馈信号可通过引出线2引入，此时，与引出线2相连的反馈支路上需连接有反馈电容。该前级音频放大器的壳体上有三个引出线端，即放大信号输出线端、接地线端和增设的引出线端2。The pre-stage audio amplifier includes a casing 1 and an internal circuit, the internal circuit includes an integrated amplifier chip G, and a lead wire 2 connected to the inverting input terminal of the integrated amplifier chip is provided on the casing. The feedback signal required by the pre-stage audio amplifier can be introduced through the lead-out line 2 , and at this time, a feedback capacitor needs to be connected to the feedback branch connected to the lead-out line 2 . There are three lead-out terminals on the housing of the pre-stage audio amplifier, namely the amplified signal output terminal, the grounding terminal and the additional lead-out terminal 2 .

在壳体内的引出线2上串接有反馈电容C2。这样，在使用时可简化与引出线2相连的反馈支路的结构，即引出线端2可直接与反馈信号采样点连接。A feedback capacitor C2 is connected in series with the lead-out line 2 inside the casing. In this way, the structure of the feedback branch connected to the lead-out line 2 can be simplified during use, that is, the lead-out line end 2 can be directly connected to the sampling point of the feedback signal.

当反馈信号频率较高时，单一电容C2的介质极化方向反复变化，不但因分子摩擦损耗增加，降低了电容反应速度，而且影响反馈信号传输的快速、准确性。为此，壳体内的引出线2上的反馈电容由电容C3、C4串联而成，并使电容C3、C4之间的连接点通过电阻R3与集成放大芯片的电源(正电源或负电源)相连。这样，通过给电容一个(足够高的)偏置电压，使反馈电容的介质极化方向始终保持不变，从而提高反馈电容对反馈信号传输的速度和准确性。When the frequency of the feedback signal is high, the polarization direction of the medium of the single capacitor C2 changes repeatedly, which not only reduces the reaction speed of the capacitor due to the increase of molecular friction loss, but also affects the speed and accuracy of the feedback signal transmission. For this reason, the feedback capacitance on the lead-out line 2 in the casing is formed by series connection of capacitors C3 and C4, and the connection point between capacitors C3 and C4 is connected to the power supply (positive power supply or negative power supply) of the integrated amplifier chip through resistor R3 . In this way, by giving the capacitor a (sufficiently high) bias voltage, the medium polarization direction of the feedback capacitor is always kept unchanged, thereby improving the speed and accuracy of the feedback signal transmission by the feedback capacitor.

Claims

1. A pre-stage audio amplifier comprising a housing (1) and an internal circuit, the internal circuit comprising an integrated amplifier chip G, characterized in that: the housing has a lead wire ( 2).

2. The pre-stage audio amplifier according to claim 1, characterized in that: a feedback capacitor (C2) is connected in series to the lead-out line (2) in the casing.

3. The pre-stage audio amplifier according to claim 2, characterized in that: the feedback capacitance on the lead-out line (2) in the housing is formed by series connection of capacitors (C3, C4), and the capacitors (C3, C4) The connecting point between them is connected to the power supply of the integrated amplifier chip through a resistor (R3).