Low-distortion amplifying circuit

Abstract

The utility model relates to the technical field of amplifying circuits, and discloses a low-distortion amplifying circuit with reliable output audio quality, which comprises a signal input circuit (110) used for receiving audio signals input by a preceding stage, a first amplifying circuit (120) and a second amplifying circuit (130), when an input level signal is at a high level, the second amplifying circuit (130) is controlled to be switched off, and when the input level signal is at a low level, the second amplifying circuit (130) is controlled to be switched off. The first amplification circuit (120) is controlled to work and amplifies the first path of signal; and when the input level signal is at a low level, the first amplification circuit (120) is controlled to be turned off, and the second amplification circuit (130) is controlled to work to amplify the second path of signal.

Description

Technical Field

[0001] This utility model relates to the field of amplifier circuit technology, and more specifically, to a low-distortion amplifier circuit. Background Technology

[0002] In practical audio amplifier systems, power amplifier circuits amplify the amplitude of the input signal while maintaining its waveform without distortion, thereby achieving linear amplification of the input signal. However, existing power amplifier circuits have low power and high distortion, resulting in limited output sound quality that is difficult to meet the needs of high-end audio equipment.

[0003] Therefore, how to achieve low-distortion signal power output has become a technical problem that urgently needs to be solved by those skilled in the art. Utility Model Content

[0004] The technical problem to be solved by this utility model is to provide a low-distortion amplifier circuit with reliable output audio quality, which addresses the shortcomings of existing power amplifier circuits, such as low power and high distortion, resulting in limited output sound quality and difficulty in meeting the needs of high-end audio equipment.

[0005] The technical solution adopted by this utility model to solve its technical problem is: to construct a low-distortion amplifier circuit, which has the following features:

[0006] The signal input circuit, which is configured within the amplifier circuit, is used to receive the audio signal input from the preamplifier.

[0007] The first amplifier circuit has one signal terminal used to receive the first signal.

[0008] A signal terminal of the first amplifier circuit is connected to the output terminal of the signal input circuit, and is used to receive the level signal output by the signal input circuit;

[0009] The second amplifier circuit has one signal terminal used to receive the second signal.

[0010] One signal terminal of the second amplifier circuit is connected to the output terminal of the signal input circuit, and is used to receive the level signal output by the signal input circuit;

[0011] When the input signal is high, the second amplifier circuit is turned off, and the first amplifier circuit is activated to amplify the first signal.

[0012] When the input signal level is low, the first amplifier circuit is turned off and the second amplifier circuit is turned on to amplify the second signal.

[0013] In some embodiments, the signal input circuit includes an operational amplifier module and a feedback module.

[0014] One input terminal of the operational amplifier module is used to receive the audio signal input from the previous stage and to perform operational amplification on the audio signal.

[0015] The other input terminal of the operational amplifier module is connected to one end of the feedback module.

[0016] The other end of the feedback module is connected to the output of the low-distortion amplifier circuit.

[0017] The output terminal of the operational amplifier module is connected to a signal terminal of the first amplifier circuit and a signal terminal of the second amplifier circuit, respectively.

[0018] In some embodiments, the operational amplifier module includes an operational amplifier, a first resistor, and a second resistor.

[0019] One end of the first resistor is connected to the output of the preceding circuit to receive the input audio signal.

[0020] The other end of the first resistor is connected to the non-inverting input of the operational amplifier and one end of the second resistor, respectively.

[0021] The inverting input of the operational amplifier is connected to one end of the feedback module.

[0022] The output terminal of the operational amplifier is connected to a signal terminal of the first amplifier circuit and a signal terminal of the second amplifier circuit, respectively.

[0023] The other end of the second resistor is connected to the common terminal.

[0024] In some embodiments, the first amplifier circuit includes at least a first transistor, a second transistor, and a third transistor.

[0025] The base and collector of the first transistor are connected to the output terminal of the operational amplifier.

[0026] The collector of the second transistor is connected to the emitter of the first transistor.

[0027] The base of the second transistor is connected to the output terminal of the first signal through a fourth resistor.

[0028] The base of the third transistor is connected to the emitter of the first transistor.

[0029] The emitter of the third transistor is connected to the load input terminal.

[0030] The emitter of the second transistor is connected to the -9V power supply terminal through the fifth resistor.

[0031] The collector of the third transistor is connected to the -9V power supply terminal.

[0032] In some embodiments, the first amplifier circuit further includes a fourth transistor.

[0033] The base of the fourth transistor is connected to the emitter of the second transistor.

[0034] The collector of the fourth transistor is connected to the base of the second transistor.

[0035] The emitter of the fourth transistor is connected to the -9V power supply terminal.

[0036] In some embodiments, the second amplifier circuit includes at least a fifth transistor, a sixth transistor, and an eighth transistor.

[0037] The base of the fifth transistor is connected to the output terminal of the second signal via the seventh resistor.

[0038] The collector of the fifth transistor is connected to the base and collector of the sixth transistor.

[0039] The emitter of the fifth transistor is connected to the +9V power supply terminal.

[0040] The emitter of the sixth transistor is connected to the output terminal of the operational amplifier.

[0041] The base of the eighth transistor is connected to the emitter of the fifth transistor.

[0042] The emitter of the eighth transistor is connected to the load input terminal through the ninth resistor.

[0043] In some embodiments, the second amplifier circuit further includes a seventh transistor.

[0044] The base of the seventh transistor is connected to the +9V power supply terminal through the eighth resistor.

[0045] The emitter of the seventh transistor is connected to the +9V power supply terminal.

[0046] The collector of the seventh transistor is connected to the base of the fifth transistor.

[0047] In some embodiments, the first transistor, the sixth transistor, and the eighth transistor are selected as NPN transistors.

[0048] The third transistor is selected as a PNP type transistor.

[0049] The low-distortion amplifier circuit described in this invention includes a signal input circuit for receiving audio signals from a preamplifier, a first amplifier circuit, and a second amplifier circuit. When the input signal is high, the second amplifier circuit is turned off, and the first amplifier circuit is activated to amplify the first signal. When the input signal is low, the first amplifier circuit is turned off, and the second amplifier circuit is activated to amplify the second signal. Compared to existing technologies, the low-distortion amplifier circuit incorporates a closed-loop voltage feedback circuit at the output load terminal, which effectively reduces the distortion of the amplifier circuit, significantly improves the quality of the audio signal, and faithfully reproduces the original flavor and details of the audio signal. Furthermore, the circuit is simple, reliable, and low-cost. Attached Figure Description

[0050] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0051] Figure 1 This is a circuit diagram of an embodiment of the low-distortion amplifier circuit provided by this utility model. Detailed Implementation

[0052] To provide a clearer understanding of the technical features, objectives, and effects of this utility model, the specific embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0053] like Figure 1 As shown, in the first embodiment of the low-distortion amplifier circuit of this utility model, the low-distortion amplifier circuit 10 includes a signal input circuit 110, a first amplifier circuit 120, and a second amplifier circuit 130.

[0054] The signal input circuit 110 has the functions of receiving, amplifying and feeding back audio signals. It is used to receive the audio signal input from the preamplifier module and amplify the audio signal in the preamplifier stage.

[0055] The first amplifier circuit 120 has the function of signal amplification and output;

[0056] The second amplifier circuit 130 has the function of signal amplification and output;

[0057] Specifically, the signal input circuit 110 is configured in the amplifier circuit to receive the audio signal input from the preamplifier module or the amplifier circuit, perform preamplification on the input audio signal, and then output it to the first amplifier circuit 120 and the second amplifier circuit 130.

[0058] Among them, a signal terminal of the first amplifier circuit 120 is used to receive the first signal input from the power amplifier module or power amplifier circuit, and to amplify the input first signal.

[0059] A signal terminal of the first amplifier circuit 120 is connected to the output terminal of the signal input circuit 110, and is used to receive the level signal output by the signal input circuit 110. The level signal is used to control the on / off state of the first amplifier circuit 120.

[0060] Furthermore, one signal terminal of the second amplifier circuit 130 is used to receive the second signal input from the power amplifier module or power amplifier circuit, and to amplify the input second signal.

[0061] A signal terminal of the second amplifier circuit 130 is connected to the output terminal of the signal input circuit 110 and is used to receive the level signal output by the signal input circuit 110. This level signal is used to control the on / off state of the first amplifier circuit 120.

[0062] When the input signal is high, the second amplifier circuit 130 is turned off and the first amplifier circuit 120 is turned on to amplify the first signal and output it to the load (corresponding to the OUT terminal).

[0063] When the input signal is low, the first amplifier circuit 120 is turned off and the second amplifier circuit 130 is turned on to amplify the second signal and output it to the load (corresponding to the OUT terminal).

[0064] Using this technical solution, a closed voltage feedback loop is added to the output load terminal of the low-distortion amplifier circuit, which can effectively reduce the distortion of the amplifier circuit, improve the signal quality, and truly reproduce the original flavor and details of the audio signal. Moreover, the circuit is simple, reliable, and low in cost.

[0065] In some implementations, in order to improve the output quality of audio signals, an operational amplifier module 111 and a feedback module 112 can be provided in the signal input circuit 110. The operational amplifier module 111 has the function of signal amplification, and the feedback module 112 is used to feed back the signal from the output side of the amplifier circuit to an input terminal of the operational amplifier module 111.

[0066] Specifically, one input terminal of the operational amplifier module 111 is used to receive the audio signal input from the power amplifier module or power amplifier circuit, and to perform operational amplification processing on the audio signal to output a level signal.

[0067] The other input terminal of the operational amplifier module 111 is connected to one end of the feedback module 112.

[0068] The other end of the feedback module 112 is connected to the output of the low-distortion amplifier circuit. The feedback module 112 feeds back the audio signal output by the low-distortion amplifier circuit to the other input of the operational amplifier module 111.

[0069] The output terminal of the operational amplifier module 111 is connected to a signal terminal of the first amplifier circuit 120 and a signal terminal of the second amplifier circuit 130, respectively.

[0070] In some implementations, in order to improve the output quality of the audio signal, an operational amplifier U101, a first resistor R101 and a second resistor R102 can be provided in the operational amplifier module 111. The resistors can be used to adjust the input impedance of the circuit so as to match the output impedance of the source device, thereby optimizing signal transmission and reducing signal reflection.

[0071] One end of the first resistor R101 is connected to the output terminal (corresponding to IN) of the preceding circuit to receive the input audio signal.

[0072] The other end of the first resistor R101 is connected to the non-inverting input (pin 5) of the operational amplifier U101 and one end of the second resistor R102, respectively. That is, the audio signal is input to the non-inverting input (pin 5) of the operational amplifier U101 through the first resistor R101.

[0073] The inverting input (pin 6) of operational amplifier U101 is connected to one end of feedback module 112. Feedback module 112 feeds back the audio signal output from the low-distortion amplifier circuit to the inverting input (pin 6) of operational amplifier U101.

[0074] The output terminal (corresponding to pin 7) of operational amplifier U101 is connected to a signal terminal of the first amplifier circuit 120 and a signal terminal of the second amplifier circuit 130, respectively, so as to input the pre-amplified audio signal into the first amplifier circuit 120 and the second amplifier circuit 130.

[0075] The other end of the second resistor R102 is connected to the common terminal.

[0076] In some embodiments, the feedback module 112 includes a third resistor R103 and a first capacitor C101 connected in parallel. One end of the third resistor R103 and the first capacitor C101 is connected to the load (corresponding to the OUT terminal), and the other end of the third resistor R103 and the first capacitor C101 is connected to the inverting terminal (corresponding to pin 6) of the operational amplifier U101, which feeds back the audio signal output by the load (corresponding to the OUT terminal) to the operational amplifier U101.

[0077] In some implementations, to improve the output quality of the audio signal, a first transistor Q101, a second transistor Q102, and a third transistor Q103 can be configured in the first amplifier circuit 120. The first transistor Q101 and the second transistor Q102 are NPN type transistors, and the third transistor Q103 is a PNP type transistor, all of which function as switches.

[0078] Specifically, the base and collector of the first transistor Q101 are connected to the output terminal (pin 7) of the operational amplifier U101.

[0079] The collector of the second transistor Q102 is connected to the emitter of the first transistor Q101.

[0080] The base of the second transistor Q102 is connected to the output terminal of the first signal (corresponding to the LINK-PP terminal) through the fourth resistor R104. The first signal is input to the base of the second transistor Q102 through the fourth resistor R104.

[0081] The base of the third transistor Q103 is connected to the emitter of the first transistor Q101.

[0082] The emitter of the third transistor Q103 is connected to the input terminal of the load (corresponding to the OUT terminal) through the sixth resistor R106.

[0083] The emitter of the second transistor Q102 is connected to the -9V power supply terminal through the fifth resistor R105.

[0084] The collector of the third transistor Q103 is connected to the -9V power supply terminal.

[0085] In some embodiments, the first amplifier circuit 120 further includes a fourth transistor Q104, a second capacitor C102, and a third capacitor C103. The transistor is selected as a PNP type and functions as a switch. The second capacitor C102 and the third capacitor C103 function as filters.

[0086] Specifically, the base of the fourth transistor Q104 is connected to the emitter of the second transistor Q102.

[0087] The collector of the fourth transistor Q104 is connected to the base of the second transistor Q102. The collector of the fourth transistor Q104 is also connected to the output terminal of the first signal (corresponding to the LINK-PP terminal) through the fourth resistor R104.

[0088] The emitter of the fourth transistor Q104 is connected to the -9V power supply terminal.

[0089] One end of the second capacitor C102 and the third capacitor C103 are connected to the -9V power supply terminal to filter the voltage signal input from the -9V power supply terminal. The other end of the second capacitor C102 and the third capacitor C103 are connected to the common terminal.

[0090] In some implementations, to improve the output quality of the audio signal, a fifth transistor Q105, a sixth transistor Q106, and an eighth transistor Q108 can be provided in the second amplifier circuit 130. The fifth transistor Q105 is selected as a PNP type transistor, while the sixth transistor Q106 and the eighth transistor Q108 are selected as NPN type transistors, all of which function as switches.

[0091] Specifically, the base of the fifth transistor Q105 is connected to the output terminal (corresponding to the LINK-PP terminal) of the second signal through the seventh resistor R107. That is, the second signal is input to the base of the fifth transistor Q105 via the seventh resistor R107.

[0092] The collector of the fifth transistor Q105 is connected to the base and collector of the sixth transistor Q106.

[0093] The emitter of the fifth transistor Q105 is connected to the +9V power supply terminal through the eighth resistor R108.

[0094] The emitter of transistor Q106 is connected to the output terminal (pin 7) of operational amplifier U101.

[0095] The base of the eighth transistor Q108 is connected to the emitter of the fifth transistor Q105.

[0096] The emitter of the eighth transistor Q108 is connected to the load (corresponding to the OUT terminal) through the ninth resistor R109.

[0097] In some embodiments, the second amplifier circuit 130 further includes a seventh transistor Q107, a fourth capacitor C104, and a fifth capacitor C105. These are selected as PNP transistors and function as switches. The fourth capacitor C104 and the fifth capacitor C105 function as filters.

[0098] In this circuit, the base of the seventh transistor Q107 is connected to the +9V power supply terminal through the eighth resistor R108.

[0099] The emitter of transistor Q107 is connected to the +9V power supply.

[0100] The collector of transistor Q107 is connected to the base of transistor Q105.

[0101] One end of the fourth capacitor C104 and the fifth capacitor C105 is connected to the +9V power supply terminal to filter the voltage signal input from the +9V power supply terminal, and the other end of the fourth capacitor C104 and the fifth capacitor C105 is connected to the common terminal.

[0102] Specifically, +9V and -9V provide power to transistors Q101-Q8 and operational amplifier U101. When the low-distortion amplifier circuit 10 is in amplification mode, and the audio signal is input to operational amplifier U101 through the first resistor R101, the input signal is divided by the first resistor R101 and the second resistor R102, and then enters the buffer amplification of pin 5 of operational amplifier U101. Then it is output from pin 7 of operational amplifier U101, clamped by the first transistor Q101 and the sixth transistor Q106, and input to the base of the third transistor Q103 and the eighth transistor Q108.

[0103] Among them, the third transistor Q103 and the eighth transistor Q108 are two heterogeneous transistors with identical characteristics. The eighth transistor Q108 conducts during the positive half-cycle of the signal input, while the third transistor Q103 conducts during the negative half-cycle of the signal input. After the input signal is amplified by the third transistor Q103 and the eighth transistor Q108, it is connected to the output terminal after being current-limited by the sixth resistor R106 and the ninth resistor R109, and output to the load (such as headphones or speakers). At the same time, the output voltage at the output terminal is fed back to the inverting terminal (corresponding to pin 6) of the operational amplifier U101 through the third resistor R103 and the first capacitor C101 to form a closed feedback loop to stabilize the operating point of the amplifier circuit.

[0104] This technical solution enables signal amplification with minimal loss and high signal fidelity, allowing users to better capture the original flavor and details of the music. It effectively solves the problems of existing power amplifier circuits having low power, high distortion, and limited sound quality, making it difficult to meet the needs of high-end audio equipment.

[0105] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A low-distortion amplification circuit, characterized by comprising: Possess: Signal input circuit, configured in the amplifier circuit, for receiving the front stage input audio signal; The first amplifier circuit, a signal end for receiving the first signal, The first amplifier circuit, a signal end and the output end of the signal input circuit are connected, for receiving the level signal output by the signal input circuit; The second amplifier circuit, a signal end for receiving the second signal, The second amplifier circuit, a signal end and the output end of the signal input circuit are connected, for receiving the level signal output by the signal input circuit; When the input level signal is high, the second amplifier circuit is controlled off, the first amplifier circuit is controlled to work, the first signal is amplified, When the input level signal is low, the first amplifier circuit is controlled off, the second amplifier circuit is controlled to work, the second signal is amplified.

2. The low distortion amplifier circuit according to claim 1, wherein The signal input circuit comprises an operational amplifier module and a feedback module, The operational amplifier module is used for receiving the front stage input audio signal and performing operational amplification on the audio signal, The other input end of the operational amplifier module is connected with one end of the feedback module, The other end of the feedback module is connected with the output end of the low distortion amplifier circuit, The output end of the operational amplifier module is connected with the signal end of the first amplifier circuit and the signal end of the second amplifier circuit respectively.

3. The low distortion amplifier circuit according to claim 2, wherein The operational amplifier module comprises an operational amplifier, a first resistor and a second resistor, One end of the first resistor is connected with the output end of the front stage circuit, for receiving the input audio signal, The other end of the first resistor is connected with the non-inverting terminal of the operational amplifier and one end of the second resistor respectively, The inverting terminal of the operational amplifier is connected with one end of the feedback module, The output end of the operational amplifier is connected with the signal end of the first amplifier circuit and the signal end of the second amplifier circuit respectively, The other end of the second resistor is connected with the common terminal.

4. The low distortion amplifier circuit according to claim 3, wherein The first amplifier circuit comprises at least a first transistor, a second transistor and a third transistor, The base and the collector of the first transistor are connected with the output end of the operational amplifier, The collector of the second transistor is connected with the emitter of the first transistor, The base of the second transistor is connected with the output end of the first signal through a fourth resistor, The base of the third transistor is connected with the emitter of the first transistor, The emitter of the third transistor is connected with the load input end, The emitter of the second transistor is connected with the -9V power supply end through a fifth resistor, The collector of the third transistor is connected with the -9V power supply end.

5. The low distortion amplifier circuit according to claim 4, wherein The first amplifier circuit further comprises a fourth transistor, The base of the fourth transistor is connected with the emitter of the second transistor, The collector of the fourth triode is connected with the base of the second triode, The emitter of the fourth triode is connected with the -9V power terminal.

6. The low-distortion amplification circuit according to claim 5, wherein, The second amplification circuit comprises at least a fifth triode, a sixth triode and an eighth triode, The base of the fifth triode is connected with the output terminal of the second signal through a seventh resistor, The collector of the fifth triode is connected with the base and the collector of the sixth triode, The emitter of the fifth triode is connected with the +9V power terminal, The emitter of the sixth triode is connected with the output terminal of the operational amplifier, The base of the eighth triode is connected with the emitter of the fifth triode, The emitter of the eighth triode is connected with the load input terminal through a ninth resistor.

7. The low-distortion amplification circuit according to claim 6, wherein, The second amplification circuit further comprises a seventh triode, The base of the seventh triode is connected with the +9V power terminal through an eighth resistor, The emitter of the seventh triode is connected with the +9V power terminal, The collector of the seventh triode is connected with the base of the fifth triode.

8. The low-distortion amplification circuit according to claim 7, wherein, The first triode, the sixth triode and the eighth triode are selected as NPN triodes, The third triode is selected as a PNP triode.

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