Audio signal amplification circuit and audio equipment

Abstract

The utility model relates to the technical field of signal processing, in particular to an audio signal amplification circuit and audio equipment. The circuit comprises a phase switching unit and a signal amplification unit, the first end of the phase switching unit is connected with an external input signal, the second end of the phase switching unit is connected with the first input end of the signal amplification unit, the third end of the phase switching unit is connected with the second input end of the signal amplification unit, and a change-over switch is arranged in the phase switching unit. When the change-over switch is in an open state, the signal amplification unit carries out voltage amplification processing on the external input signal, and when the change-over switch is in a closed state, the external input signal is subjected to phase inversion and then is subjected to voltage amplification processing. By switching the phase state of the switch, reverse or normal amplification of the signal is realized, the requirement of the audio effect is met, and the application scene of the audio equipment is expanded.

Description

TECHNICAL FIELD

[0001] The utility model relates to signal processing technical field especially relates to an audio signal amplification circuit and audio equipment. BACKGROUND

[0002] In the field of audio amplification, the traditional power amplifier (power amplifier) design usually only provides positive or negative phase amplification function, only positive or negative phase amplification is carried out, and the phase of the output signal cannot be switched in real time according to the requirements of the actual application scene. The audio output performance is poor or the application scene is limited. To change the phase of the output signal, external additional equipment is often needed, such as using a special phase converter or manually adjusting the connection cable. Not only does it increase the complexity of the system, but it also brings inconvenience to the operation, and may introduce additional noise and distortion problems.

[0003] The above content is only used to assist in understanding the technical scheme of the utility model, and does not represent the recognition of the above content as prior art. UTILITY MODEL CONTENT

[0004] The main purpose of the utility model is to provide an audio signal amplification circuit and audio equipment, which aims to solve the technical problem that the power amplifier output cannot switch the positive and negative phase output according to the actual situation.

[0005] To achieve the above purpose, in the first aspect, the utility model technical scheme provides an audio signal amplification circuit, which comprises a phase switching unit and a signal amplification unit. The first end of the phase switching unit is connected with an external input signal, the second end of the phase switching unit is connected with the first input end of the signal amplification unit, the third end of the phase switching unit is connected with the second input end of the signal amplification unit, and the phase switching unit is internally provided with a switching switch. The phase switching unit is used for transmitting the external input signal to the first input end of the signal amplification unit when the switching switch is in the open state, and transmitting the external input signal to the second input end of the signal amplification unit when the switching switch is in the closed state. The signal amplification unit is used for carrying out voltage amplification processing on the external input signal when the first input end receives the external input signal, and carrying out voltage amplification processing on the external input signal after phase inversion when the second input end receives the external input signal. By switching the phase state of the switching switch, the signal can be inverted or amplified in positive phase, meeting the requirements of audio effect and expanding the application scene of the audio equipment.

[0006] In the second aspect, the application also provides an audio equipment, which comprises the audio signal amplification circuit as described above. DRAWING DESCRIPTION

[0007] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained according to the structures shown in these drawings without creative labor.

[0008] Figure 1 The structural schematic diagram of the first embodiment of the audio signal amplification circuit of the present application;

[0009] Figure 2 The output waveform diagram of the first embodiment of the audio signal amplification circuit of the present application;

[0010] Figure 3 The circuit connection diagram of the second embodiment of the audio signal amplification circuit of the present application;

[0011] Figure 4 The circuit connection diagram of the single power supply in the second embodiment of the audio signal amplification circuit of the present application;

[0012] Figure 5 The circuit connection diagram of the third embodiment of the audio signal amplification circuit of the present application;

[0013] Figure 6 The circuit connection diagram of the single power supply in the third embodiment of the audio signal amplification circuit of the present application.

[0014] The implementation, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings.

[0015] The figure mark explanation: R1, first resistance; R2, second resistance; R3, third resistance; R4, fourth resistance; C1, first capacitor; C2, second capacitor; C3, third capacitor; C4, fourth capacitor; 10, phase switching unit; 20, signal amplification unit; 30, impedance matching unit; SW, switching switch; U1, first operational amplifier; U2, second operational amplifier. Specific implementation

[0016] It should be understood that the specific embodiments described herein are only used to explain the present application, and are not used to limit the present application.

[0017] With reference to the accompanying drawings, the technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all the other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0018] It should be noted that all the directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present application are only used to explain the relative positional relationship, movement condition, etc. between components in a certain specific posture (as shown in the drawings), and if the specific posture changes, the directional indications will also change accordingly.

[0019] In addition, the description of "first", "second" and the like in the present application is only for the purpose of description, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first", "second" can explicitly or implicitly include at least one of the features. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the realization of the ordinary skilled in the art, when the combination of the technical solutions appears contradictory or unachievable, it should be considered that the combination of the technical solutions does not exist, and is not within the protection scope required by the present application.

[0020] With reference to Figure 1 , Figure 1 The figure is a structural schematic diagram of the first embodiment of the audio signal amplification circuit.

[0021] The present application provides a first embodiment of an audio signal amplification circuit.

[0022] In the embodiment, the audio signal amplification circuit comprises a phase switching unit 10 and a signal amplification unit 20. The first end of the phase switching unit 10 is connected with an external input signal, the second end of the phase switching unit 10 is connected with the first input end of the signal amplification unit 20, the third end of the phase switching unit 10 is connected with the second input end of the signal amplification unit 20, and the phase switching unit 10 is internally provided with a switching switch SW.

[0023] It should be noted that the phase switching unit 10 can be used to transmit the external input signal (Vin) to the first input end of the signal amplification unit 20 when the switching switch SW is in the open state, and transmit the external input signal to the second input end of the signal amplification unit 20 when the switching switch SW is in the closed state. The signal amplification unit 20 can be used to perform voltage amplification processing on the external input signal when the first input end receives the external input signal, and perform voltage amplification processing on the external input signal after phase inversion when the second input end receives the external input signal.

[0024] It should be understood that the phase switching unit 10 can be an electronic device with electrical signal transmission adjustment capability, such as a power tube, a solenoid valve, or a switching circuit, etc. The switching switch SW is internally provided, which can be a push switch or a single-pole double-throw switch, etc. By adjusting the state of the switching switch SW, the electrical signal input to the phase switching unit 10 is output through different ports. The state adjustment of the switching switch SW can be triggered by the user manually pressing, or a driving circuit can be designed to trigger by electrical signal.

[0025] Further, the signal amplification unit 20 can be an electronic device with voltage amplification function, which can amplify (or reduce) the voltage amplitude of the external input signal (such as an audio signal) by a certain ratio (such as twice). The voltage amplitude of the audio signal is usually low during generation, transmission and processing. The signal amplification unit is used to amplify these low-voltage audio signals to a sufficient amplitude, so that the loudspeaker or other output device can effectively convert these signals into sound or other signals. Because different audio output devices (such as loudspeakers) have different requirements for voltage amplitude. The signal amplification unit 20 can adapt the voltage amplitude of the signal to a suitable level matched with the audio output device by different proportional amplification.

[0026] It should be understood that the signal amplification unit 20 can simultaneously have a signal inversion function, which can convert positive voltage to negative voltage and negative voltage to positive voltage. The signal achieves the same proportional amplification of positive or negative output through different input ports. The signal input through the first input end is directly amplified and output, and the signal input through the second input end is amplified after phase inversion.

[0027] Referring to Figure 2 , Figure 2The output waveform diagram of the first embodiment of the audio signal amplification circuit of the utility model. The waveform with higher amplitude is the external input signal, and the waveform with lower amplitude is the output signal of the signal amplification unit. When the switch SW is in the open state, the phase switching unit 10 controls the external input signal to be transmitted to the first input end of the signal amplification unit 20, and the signal amplification unit 20 outputs after voltage amplification processing of the external input signal, referring to the waveform of the T1 time period in the figure, the phase of the input and output signals is the same. When the switch SW is in the closed state, the phase switching unit 10 controls the external input signal to be transmitted to the second input end of the signal amplification unit 20, and the signal amplification unit 20 outputs after voltage amplification processing of the phase-inverted external input signal, referring to the waveform of the T2 time period in the figure, the phase of the input and output signals is opposite.

[0028] The embodiment proposes an audio signal amplification circuit, which comprises a phase switching unit and a signal amplification unit. The first end of the phase switching unit is connected with an external input signal, the second end of the phase switching unit is connected with the first input end of the signal amplification unit, the third end of the phase switching unit is connected with the second input end of the signal amplification unit, and the phase switching unit is internally provided with a switch. The phase switching unit is used for transmitting the external input signal to the first input end of the signal amplification unit when the switch is in the open state, and transmitting the external input signal to the second input end of the signal amplification unit when the switch is in the closed state. The signal amplification unit is used for voltage amplification processing of the external input signal when the first input end receives the external input signal, and voltage amplification processing of the phase-inverted external input signal when the second input end receives the external input signal. By switching the phase state of the switch, signal inversion or positive phase amplification is realized, the requirements of audio effects are met, and the application scenarios of audio equipment are expanded.

[0029] Referring to Figure 3 , Figure 3 The utility model discloses an audio signal amplification circuit second embodiment's circuit connection drawing. Based on the first embodiment of the above-mentioned audio signal amplification circuit, the second embodiment of the utility model audio signal amplification circuit is proposed. In the second embodiment, the same or similar content as the above embodiment can refer to the introduction above, and the following will not be repeated.

[0030] The phase switching unit 10 comprises a first resistor R1, a second resistor R2 and a third resistor R3. The first end of the first resistor R1 is connected with the first end of the second resistor R2, the first end of the third resistor R3 and the external input signal, the second end of the first resistor R1 is connected with the first input end of the signal amplification unit 20 and the first end of the switching switch SW, the second end of the second resistor R2 is connected with the second input end of the signal amplification unit 20, and the second end of the third resistor R3 is connected with the second end of the switching switch SW and grounded.

[0031] Further, the signal amplification unit 20 comprises a first operational amplifier U1 and a fourth resistor R4. The non-inverting input end of the first operational amplifier U1 is connected with the second end of the first resistor R1, the inverting input end of the first operational amplifier U1 is connected with the second end of the second resistor R2 and the first end of the fourth resistor R4, and the output end of the first operational amplifier U1 is connected with the second end of the fourth resistor R4. In this embodiment, the switching switch SW is a touch switch.

[0032] It should be noted that when the switching switch SW is in the open state, the external input signal is transmitted to the non-inverting input end and the inverting input end of the first operational amplifier U1 through the first resistor R1 and the second resistor R2 respectively, forming a differential input. The signal amplified by the first operational amplifier U1 is output from the output end and fed back to the inverting input end of the first operational amplifier U1 through the fourth resistor R4, forming a negative feedback. According to the "virtual short and virtual open" state of the operational amplifier in the negative feedback working mode, the first operational amplifier U1 and the surrounding circuit constitute a non-inverting negative feedback amplification circuit, and the amplification factor A can be calculated according to the formula: A = R4 / R1. The resistance values of the fourth resistor R4 and the first resistor R1 are adjusted to adjust the amplification factor (for example, both are set to 10K ohms, and the amplification factor is 1), so as to realize the signal non-inverting amplification output. When the switching switch SW is in the closed state, the external input signal is transmitted to the non-inverting input end and the inverting input end of the first operational amplifier U1 through the first resistor R1 and the second resistor R2 respectively. Since the switching switch SW is in the closed state, the non-inverting input end of the first operational amplifier U1 is grounded. The signal amplified by the inverting input end of the first operational amplifier U1 is output from the output end and fed back to the inverting input end of the first operational amplifier U1 through the fourth resistor R4, forming a negative feedback. According to the "virtual short and virtual open" state of the operational amplifier in the negative feedback working mode, the first operational amplifier U1 and the surrounding circuit constitute an inverting negative feedback amplification circuit, and the amplification factor A can be calculated according to the formula: A = -R4 / R2. The resistance values of the fourth resistor R4 and the second resistor R2 are adjusted to adjust the amplification factor (for example, both are set to 10K ohms, and the amplification factor is -1), so as to realize the signal inverting amplification output.

[0033] Furthermore, since the audio signal of the audio device is an AC signal, the DC signal needs to be isolated and filtered, which can be achieved using a capacitor. The signal amplification unit 20 also includes: a first capacitor C1; the first end of the first capacitor C1 is connected to the output terminal of the first operational amplifier U1, and the second end of the first capacitor C1 is connected to the load. The voltage flowing through the load is the output voltage of the audio signal amplification circuit.

[0034] It should be understood that operational amplifiers in audio devices can operate in two modes: dual power supply and single power supply. In dual power supply mode, the positive power supply terminal of the first operational amplifier U1 is connected to the positive power supply voltage (VCC), and the negative power supply terminal is connected to the negative power supply voltage (VDD). Figure 3 Take the dual power supply mode as an example.

[0035] Reference Figure 4 , Figure 4 This is a circuit connection diagram for a single-supply operation in the second embodiment of the audio signal amplification circuit of this utility model. In the single-supply mode, the positive power supply terminal of the first operational amplifier U1 is connected to the positive power supply voltage, the negative power supply terminal of the first operational amplifier U1 is grounded, and the non-inverting input terminal of the first operational amplifier U1 is connected to the reference voltage (VREF1). The reference voltage can be the neutral point voltage at which the operational amplifier operates in the single-supply mode; for example, half of the positive power supply voltage can be used as the reference voltage.

[0036] Furthermore, in order to isolate the DC level signal of the reference voltage that increases during the use of a single power supply, the phase switching unit 10 further includes: a second capacitor C2; the first end of the second capacitor C2 is connected to the first end of the switching switch SW, and the second end of the second capacitor C2 is grounded.

[0037] In this embodiment, the phase switching unit includes a first resistor, a second resistor, and a third resistor; the signal amplification unit includes a first operational amplifier and a fourth resistor. By switching the phase state of the switch, the external input signal can be transmitted to either the non-inverting or inverting input of the first operational amplifier to achieve either non-inverting or inverting amplification, meeting audio performance requirements and expanding the application scenarios of the audio equipment. Simultaneously, the first and second capacitors are used for DC blocking to ensure stable signal output performance.

[0038] Reference Figure 5 , Figure 5 This is a circuit connection diagram of the third embodiment of the audio signal amplification circuit of this utility model. Based on the above embodiments of the audio signal amplification circuit, a third embodiment of the audio signal amplification circuit of this utility model is proposed.

[0039] The audio signal amplification circuit further includes an impedance matching unit 30. The input terminal of the impedance matching unit 30 is connected to the external input signal, and the output terminal of the impedance matching unit 30 is connected to the first terminal of the phase switching unit 10.

[0040] It should be noted that the impedance matching unit 30 can be used to adjust the input impedance of the audio signal amplification circuit to match the input impedance of the external input signal.

[0041] It should be understood that an impedance matching unit is an electronic device used to adjust the impedance between different parts of a circuit, ensuring that signals are not reflected or lost during transmission. By changing the impedance value in the circuit to accommodate different signal input impedances, the efficiency of signal transmission and energy conversion is optimized. For example, connecting a resistor in series increases the total impedance of the circuit, while connecting a resistor in parallel decreases the total impedance. Using an impedance matching unit in audio transmission ensures that the audio signal is transmitted to the load at maximum power, reducing signal distortion.

[0042] In one possible implementation, the impedance matching unit 30 includes a second operational amplifier U2; the non-inverting input of the second operational amplifier U2 is connected to the external input signal, and the inverting input of the second operational amplifier U2 is connected to its output and the first terminal of the phase switching unit 10. The external input signal enters the buffer formed by the second operational amplifier U2, realizing a 1:1 positive-phase low-impedance signal output from the output of the second operational amplifier U2, which can adapt to different signal input impedances.

[0043] Furthermore, the impedance matching unit 30 may further include a third capacitor C3 and a fourth capacitor C4. The first end of the third capacitor C3 is connected to the external input signal, the second end of the third capacitor C3 is connected to the non-inverting input terminal of the second operational amplifier U2, the first end of the fourth capacitor C4 is connected to the output terminal of the second operational amplifier U2, and the second end of the fourth capacitor C4 is connected to the first end of the phase switching unit 10.

[0044] It should be noted that the external input signal is input to the non-inverting input of the second operational amplifier U2 through the third capacitor C3 (DC blocking). After impedance matching by the buffer, it is output from the output terminal and then coupled through the fourth capacitor to the third resistor R3. When the switch SW is open, the signal is transmitted to the non-inverting and inverting inputs of the first operational amplifier U1 through the first resistor R1 and the second resistor R2, respectively, forming a differential input. The signal amplified by the first operational amplifier U1 is output from the output terminal and fed back to the inverting input of the first operational amplifier U1 through the fourth resistor R4, forming negative feedback. According to the "virtual short and virtual open" state of the operational amplifier in the negative feedback operating mode, the first operational amplifier U1 and its surrounding circuits constitute a positive-inverting negative feedback amplifier circuit, achieving the effect of in-phase signal amplification. High-fidelity output is achieved through DC blocking coupling by the first capacitor C1. When the switch SW is closed, the external input signal is transmitted to the non-inverting and inverting inputs of the first operational amplifier U1 through the first resistor R1 and the second resistor R2, respectively. Since the switch SW is closed, the non-inverting input of the first operational amplifier U1 is grounded. The signal amplified by the inverting input of the first operational amplifier U1 is output from the output terminal and fed back to the inverting input of the first operational amplifier U1 via the fourth resistor R4, forming negative feedback. According to the "virtual short and virtual open" state of the operational amplifier in the negative feedback working mode, the first operational amplifier U1 and its surrounding circuits constitute an inverting negative feedback amplifier circuit to achieve the effect of inverting the signal amplification, and output it through the DC blocking coupling of the first capacitor C1.

[0045] Reference Figure 6 , Figure 6 This is a circuit connection diagram for a single power supply in the third embodiment of the audio signal amplification circuit of this utility model. Similar to the first operational amplifier U1, the second operational amplifier U2 also has a single power supply mode. In the single power supply mode, the positive power supply terminal of the second operational amplifier U2 is connected to the positive power supply voltage VCC, the negative power supply terminal of the second operational amplifier U2 is grounded, and the non-inverting input terminal of the second operational amplifier U2 is connected to the reference voltage (VREF2).

[0046] In this embodiment, the audio signal amplification circuit further includes an impedance matching unit; the input terminal of the impedance matching unit is connected to the external input signal, and the output terminal of the impedance matching unit is connected to the first terminal of the phase switching unit; the impedance matching unit is used to adjust the input impedance of the audio signal amplification circuit to match the input impedance of the external input signal. It can adapt to different signal input impedances and can therefore be applied to audio-related products such as professional power amplifiers, analog power amplifiers, speakers, and mixing consoles to achieve analog audio phase switching functionality, while maintaining low circuit cost.

[0047] Furthermore, this embodiment of the invention also proposes an audio device. The audio device includes the audio signal amplification circuit described above.

[0048] Since the audio device adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be repeated here.

[0049] The above description is only a preferred embodiment of the present utility model and does not limit the patent scope of the present utility model. All equivalent structural transformations made under the inventive concept of the present utility model using the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present utility model.

Claims

1. An audio signal amplification circuit, characterized in that, The audio signal amplification circuit includes: a phase switching unit and a signal amplification unit; The first end of the phase switching unit is connected to an external input signal, the second end of the phase switching unit is connected to the first input end of the signal amplification unit, the third end of the phase switching unit is connected to the second input end of the signal amplification unit, and a switching switch is provided inside the phase switching unit. The phase switching unit is used to transmit the external input signal to the first input terminal of the signal amplification unit when the switching switch is in the open state, and to transmit the external input signal to the second input terminal of the signal amplification unit when the switching switch is in the closed state. The signal amplification unit is used to amplify the voltage of the external input signal when it receives the external input signal at the first input terminal, and to amplify the voltage of the external input signal after reversing its phase when it receives the external input signal at the second input terminal.

2. The audio signal amplification circuit as described in claim 1, characterized in that, The phase switching unit includes: a first resistor, a second resistor, and a third resistor; The first end of the first resistor is connected to the first end of the second resistor, the first end of the third resistor, and the external input signal. The second end of the first resistor is simultaneously connected to the first input end of the signal amplification unit and the first end of the switching switch. The second end of the second resistor is connected to the second input end of the signal amplification unit. The second end of the third resistor is connected to the second end of the switching switch and grounded.

3. The audio signal amplification circuit as described in claim 2, characterized in that, The signal amplification unit includes: a first operational amplifier and a fourth resistor; The non-inverting input of the first operational amplifier is connected to the second end of the first resistor, the inverting input of the first operational amplifier is connected to the second end of the second resistor and the first end of the fourth resistor, and the output of the first operational amplifier is connected to the second end of the fourth resistor.

4. The audio signal amplification circuit as described in claim 3, characterized in that, The signal amplification unit further includes: a first capacitor; The first terminal of the first capacitor is connected to the output terminal of the first operational amplifier, and the second terminal of the first capacitor is connected to the load.

5. The audio signal amplification circuit as described in claim 3, characterized in that, The positive power supply terminal of the first operational amplifier is connected to the positive power supply voltage, the negative power supply terminal of the first operational amplifier is grounded, and the non-inverting input terminal of the first operational amplifier is connected to the reference voltage. The phase switching unit includes: a second capacitor; The first terminal of the second capacitor is connected to the first terminal of the switching switch, and the second terminal of the second capacitor is grounded.

6. The audio signal amplification circuit as described in claim 1, characterized in that, The audio signal amplification circuit further includes: an impedance matching unit; The input terminal of the impedance matching unit is connected to the external input signal, and the output terminal of the impedance matching unit is connected to the first terminal of the phase switching unit. The impedance matching unit is used to adjust the input impedance of the audio signal amplification circuit to match the input impedance of the external input signal.

7. The audio signal amplification circuit as described in claim 6, characterized in that, The impedance matching unit includes: a second operational amplifier; The non-inverting input of the second operational amplifier is connected to the external input signal, and the inverting input of the second operational amplifier is connected to the output of the second operational amplifier and the first end of the phase switching unit.

8. The audio signal amplification circuit as described in claim 7, characterized in that, The impedance matching unit further includes: a third capacitor and a fourth capacitor; The first end of the third capacitor is connected to the external input signal, the second end of the third capacitor is connected to the non-inverting input of the second operational amplifier, the first end of the fourth capacitor is connected to the output of the second operational amplifier, and the second end of the fourth capacitor is connected to the first end of the phase switching unit.

9. The audio signal amplification circuit as described in claim 8, characterized in that, The positive power supply terminal of the second operational amplifier is connected to the positive power supply voltage, the negative power supply terminal of the second operational amplifier is grounded, and the non-inverting input terminal of the second operational amplifier is connected to the reference voltage.

10. An audio device, characterized in that, The audio device includes the audio signal amplification circuit as described in any one of claims 1-9.

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