A high fidelity audio limiting circuit

Abstract

The application provides a high-fidelity audio limiting circuit, comprising: an audio amplification component and a limiting control component; the output end of the audio amplification component is connected with the input end of the limiting control component; the input end of the audio amplification component is connected with the output end of the limiting control component; when an audio input signal is transmitted to the audio amplification component, the amplification signal of the audio amplification component is transmitted to the input end of the limiting control component, the limiting signal of the limiting control component is transmitted to the input end of the audio amplification component, and the output end of the audio amplification component outputs an audio output signal. The application improves the fidelity of the audio output signal by feedback adjustment of the input end of the audio amplification component by the limiting control component.

Description

Technical Field

[0001] This application relates to the field of audio control circuits, specifically to a high-fidelity audio limiting circuit. Background Technology

[0002] An audio limiting circuit is a circuit used to control the amplitude of an audio signal to prevent excessive signal strength from causing distortion or other adverse effects. Limiters protect speakers, amplifiers, and other audio equipment from overload damage by limiting the maximum signal level and ensuring that the audio signal remains within a safe and acceptable range.

[0003] Existing audio limiting circuits typically use diodes as limiting elements. When the input signal voltage exceeds the diode's forward voltage, the diode begins to conduct and limits the signal from increasing further.

[0004] However, when the input signal approaches the limiting threshold, the existing audio limiting circuit can easily cause a certain degree of nonlinear distortion, affecting the audio output effect. Utility Model Content

[0005] In view of the aforementioned problems, this application is made in order to provide a high-fidelity audio limiting circuit that overcomes or at least partially solves the aforementioned problems.

[0006] This application provides a high-fidelity audio limiting circuit, including: an audio amplification component and a limiting control component; The output terminal of the audio amplification component is connected to the input terminal of the limiting control component; the input terminal of the audio amplification component is connected to the output terminal of the limiting control component. When the audio input signal is transmitted to the audio amplification component, the amplification signal of the audio amplification component is transmitted to the input terminal of the limiting control component, the limiting signal of the limiting control component is transmitted to the input terminal of the audio amplification component, and the output terminal of the audio amplification component outputs an audio output signal.

[0007] Furthermore, the limiting control component includes: transistor Q1, transistor Q2, diode D1, and diode D2; The negative terminal of diode D1 is connected to the control terminal of transistor Q2; the positive terminal of diode D2 is connected to the control terminal of transistor Q1. The input terminals of transistor Q1 and transistor Q2 are connected to the input terminal of the audio amplification component; The output terminals of transistor Q1 and transistor Q2 are connected to ground. When the audio input signal is transmitted to the audio amplification component, the positive periodic signal of the amplified signal is transmitted to the control terminal of transistor Q2 through diode D1, and the negative periodic signal of the amplified signal is transmitted to the control terminal of transistor Q1 through diode D2. Transistor Q1 and transistor Q2 are turned on and the audio input signal is shunted.

[0008] Furthermore, transistor Q1 is a PNP transistor, and transistor Q2 is an NPN transistor; The negative terminal of diode D1 is connected to the base of transistor Q2; the positive terminal of diode D2 is connected to the base of transistor Q1. The input terminal of the audio amplification component is connected to the collector of transistor Q1 and the collector of transistor Q2. The emitters of transistor Q1 and transistor Q2 are connected to ground.

[0009] Furthermore, the limiting control component includes: capacitor C3 and capacitor C4; One end of capacitor C3 is connected to the negative terminal of diode D1; the other end of capacitor C3 is connected to ground. One end of capacitor C4 is connected to the positive terminal of diode D2; the other end of capacitor C4 is connected to ground.

[0010] Furthermore, the limiting control component includes: resistor R5 and resistor R6; One end of resistor R5 is connected to the negative terminal of diode D1; the other end of resistor R5 is connected to the control terminal of transistor Q2. One end of the resistor R6 is connected to the positive terminal of the diode D2; the other end of the resistor R6 is connected to the control terminal of the transistor Q1.

[0011] Furthermore, the limiting control component includes: resistor R4, capacitor C1, and capacitor C2; One end of capacitor C2 is connected to the output terminal of the audio amplifier component; the other end of capacitor C2 is connected to one end of resistor R4; the other end of resistor R4 is connected to the positive terminal of diode D1 and the negative terminal of diode D2. One end of capacitor C1 is connected to the input terminal of the audio amplification component; the other end of capacitor C1 is connected to the output terminals of transistor Q1 and transistor Q2.

[0012] Furthermore, the audio amplification component includes: amplifier U1A; The inverting input terminal of the amplifier U1A is connected to the output terminal of the limiting control component; the non-inverting input terminal of the amplifier U1A is grounded; the output terminal of the amplifier U1A is connected to the input terminal of the limiting control component. When the audio input signal is transmitted to the audio amplification component, the audio input signal is input from the inverting input terminal of the amplifier U1A, the limiting signal of the limiting control component is transmitted to the inverting input terminal of the amplifier U1A, and the audio output signal is output from the output terminal of the amplifier U1A.

[0013] Furthermore, the audio amplification component includes: resistors R1, R2, and R3; One end of resistor R2 is connected to one end of resistor R3 and the output terminal of the limiting control component; the other end of resistor R3 is connected to one end of resistor R1 and the inverting input terminal of amplifier U1A; the other end of resistor R1 is connected to the output terminal of amplifier U1A and the input terminal of the limiting control component. When the audio input signal is transmitted to the audio amplification component, the audio input signal is input from the other end of the resistor R2, and the feedback signal of the output terminal of the amplifier U1A is transmitted to the inverting input terminal of the amplifier U1A through the resistor R1.

[0014] This application has the following advantages: In the embodiments of this application, addressing the issue that existing audio limiting circuits easily lead to a certain degree of nonlinear distortion, affecting audio output quality, this application provides a solution that uses a limiting control component to provide feedback adjustment to the input of an audio amplification component. Specifically, it includes: an audio amplification component and a limiting control component; the output terminal of the audio amplification component is connected to the input terminal of the limiting control component; the input terminal of the audio amplification component is connected to the output terminal of the limiting control component; when an audio input signal is transmitted to the audio amplification component, the amplified signal of the audio amplification component is transmitted to the input terminal of the limiting control component, the limiting signal of the limiting control component is transmitted to the input terminal of the audio amplification component, and the output terminal of the audio amplification component outputs an audio output signal. This application improves the fidelity of the audio output signal by using a limiting control component to provide feedback adjustment to the input terminal of the audio amplification component. Attached Figure Description

[0015] To more clearly illustrate the technical solution of this application, the drawings used in the description of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1This is a structural block diagram of a high-fidelity audio limiting circuit provided in one embodiment of this application; Figure 2 This is a schematic diagram of the circuit structure of a high-fidelity audio limiting circuit provided in one embodiment of this application. Detailed Implementation

[0017] To make the objectives, features, and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0018] The inventors discovered through analysis of existing technology that when traditional limiting circuits use diodes as limiting elements, the diode's current-voltage characteristic is non-linear near the conduction voltage region. When the input signal approaches the limiting threshold, the diode's conduction behavior causes non-linear compression of the signal amplitude. This non-linearity causes signal distortion near the limiting point, affecting the purity and quality of the audio output, resulting in degraded sound quality and unnatural sound effects.

[0019] Reference Figure 1 This illustration shows a high-fidelity audio limiting circuit according to an embodiment of the present application, including: an audio amplification component and a limiting control component; The output terminal of the audio amplification component is connected to the input terminal of the limiting control component; the input terminal of the audio amplification component is connected to the output terminal of the limiting control component. When the audio input signal is transmitted to the audio amplification component, the amplification signal of the audio amplification component is transmitted to the input terminal of the limiting control component, the limiting signal of the limiting control component is transmitted to the input terminal of the audio amplification component, and the output terminal of the audio amplification component outputs an audio output signal.

[0020] In the embodiments of this application, addressing the issue that existing audio limiting circuits easily lead to a certain degree of nonlinear distortion, affecting audio output quality, this application provides a solution that uses a limiting control component to provide feedback adjustment to the input of an audio amplification component. Specifically, it includes: an audio amplification component and a limiting control component; the output terminal of the audio amplification component is connected to the input terminal of the limiting control component; the input terminal of the audio amplification component is connected to the output terminal of the limiting control component; when an audio input signal is transmitted to the audio amplification component, the amplified signal of the audio amplification component is transmitted to the input terminal of the limiting control component, the limiting signal of the limiting control component is transmitted to the input terminal of the audio amplification component, and the output terminal of the audio amplification component outputs an audio output signal. This application improves the fidelity of the audio output signal by using a limiting control component to provide feedback adjustment to the input terminal of the audio amplification component.

[0021] The following will further describe a high-fidelity audio limiting circuit in this exemplary embodiment.

[0022] Reference Figure 2 In one embodiment of this application, the limiting control component includes: transistor Q1, transistor Q2, diode D1, and diode D2; The negative terminal of diode D1 is connected to the control terminal of transistor Q2; the positive terminal of diode D2 is connected to the control terminal of transistor Q1. The input terminals of transistor Q1 and transistor Q2 are connected to the input terminal of the audio amplification component; The output terminals of transistor Q1 and transistor Q2 are connected to ground. When the audio input signal is transmitted to the audio amplification component, the positive periodic signal of the amplified signal is transmitted to the control terminal of transistor Q2 through diode D1, and the negative periodic signal of the amplified signal is transmitted to the control terminal of transistor Q1 through diode D2. Transistor Q1 and transistor Q2 are turned on and the audio input signal is shunted.

[0023] It should be noted that, based on the conduction characteristics of diodes D1 and D2, positive periodic signals can only be transmitted through diode D1 and not through diode D2, and negative periodic signals can only be transmitted through diode D2 and not through diode D1.

[0024] Based on the conduction characteristics of transistors Q1 and Q2, since the conduction of transistors Q1 and Q2 requires the on-state voltage to be reached at their control terminals, when the peak value of the amplified signal is small, transistors Q1 and Q2 are in the off state, and the limiting control component does not shunt the audio input signal, thus having no effect on the audio input and output signals. However, when the peak value of the amplified signal is large, transistors Q1 and Q2 are in the on state, and transistors Q1 and Q2 together attenuate the audio input signal. After the attenuated audio input signal is amplified by the audio amplification component, since the amplification factor remains unchanged but the input becomes smaller, the resulting audio output signal becomes smaller, thereby achieving limiting.

[0025] Positive periodic signals correspond to the peaks of amplified signals, while negative periodic signals correspond to the troughs. Based on this principle, this embodiment can control transistor Q1 using the peak-to-trough of a negative periodic signal and control transistor Q2 using the peak-to-peak of a positive periodic signal. Therefore, the limiting control component of this embodiment can fully sample the signal peaks, avoiding distortion. Furthermore, it has a simple structure, low cost, and contributes to product miniaturization. Actual testing showed that when the audio input signal exceeds the limit by three times, the total harmonic distortion (THD) of the circuit using the limiting control component of this embodiment is only 2%.

[0026] In one embodiment of this application, transistor Q1 is a PNP transistor and transistor Q2 is an NPN transistor; The negative terminal of diode D1 is connected to the base of transistor Q2; the positive terminal of diode D2 is connected to the base of transistor Q1. The input terminal of the audio amplification component is connected to the collector of transistor Q1 and the collector of transistor Q2. The emitters of transistor Q1 and transistor Q2 are connected to ground.

[0027] It should be noted that, in this embodiment, when a positive periodic signal with a peak value greater than the conduction threshold is transmitted to the base of NPN transistor Q2, NPN transistor Q2 conducts and shunts the audio input signal; when a negative periodic signal with a peak value greater than the conduction threshold is transmitted to the base of PNP transistor Q1, PNP transistor Q1 conducts and shunts the audio input signal.

[0028] It should be understood that this embodiment achieves feedback of the amplified signal by transmitting the positive periodic signal and the negative periodic signal to two different transistors for control, and then controls the attenuation of the audio input signal by transistors Q1 and Q2 together. Without departing from the above inventive concept, as an example, transistors Q1 and Q2 can also be MOS transistors or junction field-effect transistors, etc.

[0029] In one embodiment of this application, the limiting control component includes: capacitor C3 and capacitor C4; One end of capacitor C3 is connected to the negative terminal of diode D1; the other end of capacitor C3 is connected to ground. One end of capacitor C4 is connected to the positive terminal of diode D2; the other end of capacitor C4 is connected to ground.

[0030] It should be noted that capacitors C3 and C4 can complement the nonlinear changes in the voltages sampled from diodes D1 and D2. For example, when the amplified signal is in a negative cycle, capacitor C3 is in a discharging state, its voltage gradually decreases, and the resistance of transistor Q2 gradually increases, exhibiting a nonlinear state. At the same time, capacitor C4 is in a charging state, and the resistance of transistor Q1 gradually decreases. The reverse changes in the resistance values ​​of transistors Q1 and Q2 can compensate for these changes, keeping the parallel resistor value stable and avoiding audio distortion caused by the nonlinear state of the transistors when the resistance changes.

[0031] When the amplified signal is in a positive period, similarly, the resistance of transistor Q2 gradually decreases while the resistance of transistor Q2 gradually increases. The nonlinear states of transistors Q1 and Q2 compensate for each other, resulting in near-linear performance, avoiding audio distortion, and achieving high fidelity.

[0032] It should be understood that, due to the presence of capacitors C3 and C4, changes in the positive and negative cycles of the amplified signal will only alter the charging and discharging states of capacitors C3 and C4, and will not directly affect the conduction states of transistors Q1 and Q2.

[0033] In one embodiment of this application, the limiting control component includes: resistor R5 and resistor R6; One end of resistor R5 is connected to the negative terminal of diode D1; the other end of resistor R5 is connected to the control terminal of transistor Q2. One end of the resistor R6 is connected to the positive terminal of the diode D2; the other end of the resistor R6 is connected to the control terminal of the transistor Q1.

[0034] It should be noted that resistor R5 can be used to limit the current of the amplified signal at the control terminal of transistor Q2; resistor R6 can be used to limit the current of the amplified signal at the control terminal of transistor Q1.

[0035] In one embodiment of this application, the limiting control component includes: resistor R4, capacitor C1, and capacitor C2; One end of capacitor C2 is connected to the output terminal of the audio amplifier component; the other end of capacitor C2 is connected to one end of resistor R4; the other end of resistor R4 is connected to the positive terminal of diode D1 and the negative terminal of diode D2. One end of capacitor C1 is connected to the input terminal of the audio amplification component; the other end of capacitor C1 is connected to the output terminals of transistor Q1 and transistor Q2.

[0036] It should be noted that the resistor R4 can be used to limit the current of the amplified signal at the input of the amplitude limiting control component; the capacitors C1 and C2 can be used to block the DC component in the audio signal, allowing only the AC signal to pass through.

[0037] In one embodiment of this application, the audio amplification component includes: amplifier U1A; The inverting input terminal of the amplifier U1A is connected to the output terminal of the limiting control component; the non-inverting input terminal of the amplifier U1A is grounded; the output terminal of the amplifier U1A is connected to the input terminal of the limiting control component. When the audio input signal is transmitted to the audio amplification component, the audio input signal is input from the inverting input terminal of the amplifier U1A, the limiting signal of the limiting control component is transmitted to the inverting input terminal of the amplifier U1A, and the audio output signal is output from the output terminal of the amplifier U1A.

[0038] It should be noted that the amplifier U1A is the core component of the audio amplification assembly, and its function is to amplify the audio input signal to the required amplitude level and output an audio output signal.

[0039] In one embodiment of this application, the audio amplification component includes: resistor R1, resistor R2, and resistor R3; One end of resistor R2 is connected to one end of resistor R3 and the output terminal of the limiting control component; the other end of resistor R3 is connected to one end of resistor R1 and the inverting input terminal of amplifier U1A; the other end of resistor R1 is connected to the output terminal of amplifier U1A and the input terminal of the limiting control component. When the audio input signal is transmitted to the audio amplification component, the audio input signal is input from the other end of the resistor R2, and the feedback signal of the output terminal of the amplifier U1A is transmitted to the inverting input terminal of the amplifier U1A through the resistor R1.

[0040] It should be noted that resistor R1 serves as the feedback resistor for amplifier U1A, and resistors R2 and R3 together constitute the input resistor for amplifier U1A. The above structure forms a negative feedback loop, enabling amplifier U1A to operate in the linear amplification region. The amplification factor can be precisely set by adjusting the resistance values ​​of resistors R1, R2, and R3.

[0041] In the above embodiments of this application, the feedback function of the limiting control component is not affected by the specific technical solution of the audio amplification component, and the audio amplification component in the above embodiments can be other types of amplification circuits. Furthermore, the order of some series-connected components can be changed without affecting the functionality of the components; for example, the series connection order of capacitor C2 and resistor R4 can be changed.

[0042] Although preferred embodiments of the present application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the embodiments of the present application.

[0043] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or terminal device that includes said element.

[0044] The high-fidelity audio limiting circuit provided in this application has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A high-fidelity audio limiting circuit, characterized in that, include: Audio amplification components and limiting control components; The output of the audio amplification component is connected to the input of the limiting control component; The input terminal of the audio amplification component is connected to the output terminal of the limiting control component; When the audio input signal is transmitted to the audio amplification component, the amplification signal of the audio amplification component is transmitted to the input terminal of the limiting control component, the limiting signal of the limiting control component is transmitted to the input terminal of the audio amplification component, and the output terminal of the audio amplification component outputs an audio output signal.

2. The circuit according to claim 1, characterized in that, The limiting control component includes: transistor Q1, transistor Q2, diode D1, and diode D2; The negative terminal of diode D1 is connected to the control terminal of transistor Q2; the positive terminal of diode D2 is connected to the control terminal of transistor Q1. The input terminals of transistor Q1 and transistor Q2 are connected to the input terminal of the audio amplification component; The output terminals of transistor Q1 and transistor Q2 are connected to ground. When the audio input signal is transmitted to the audio amplification component, the positive periodic signal of the amplified signal is transmitted to the control terminal of transistor Q2 through diode D1, and the negative periodic signal of the amplified signal is transmitted to the control terminal of transistor Q1 through diode D2. Transistor Q1 and transistor Q2 are turned on and the audio input signal is shunted.

3. The circuit according to claim 2, characterized in that, The transistor Q1 is a PNP transistor, and the transistor Q2 is an NPN transistor; The negative terminal of diode D1 is connected to the base of transistor Q2; the positive terminal of diode D2 is connected to the base of transistor Q1. The input terminal of the audio amplification component is connected to the collector of transistor Q1 and the collector of transistor Q2. The emitters of transistor Q1 and transistor Q2 are connected to ground.

4. The circuit according to claim 2, characterized in that, The limiting control component includes: capacitor C3 and capacitor C4; One end of capacitor C3 is connected to the negative terminal of diode D1; the other end of capacitor C3 is connected to ground. One end of capacitor C4 is connected to the positive terminal of diode D2; the other end of capacitor C4 is connected to ground.

5. The circuit according to claim 4, characterized in that, The limiting control component includes: resistor R5 and resistor R6; One end of resistor R5 is connected to the negative terminal of diode D1; the other end of resistor R5 is connected to the control terminal of transistor Q2. One end of the resistor R6 is connected to the positive terminal of the diode D2; the other end of the resistor R6 is connected to the control terminal of the transistor Q1.

6. The circuit according to claim 4, characterized in that, The limiting control component includes: resistor R4, capacitor C1, and capacitor C2; One end of capacitor C2 is connected to the output terminal of the audio amplifier component; the other end of capacitor C2 is connected to one end of resistor R4; the other end of resistor R4 is connected to the positive terminal of diode D1 and the negative terminal of diode D2. One end of capacitor C1 is connected to the input terminal of the audio amplification component; the other end of capacitor C1 is connected to the output terminals of transistor Q1 and transistor Q2.

7. The circuit according to claim 1, characterized in that, The audio amplification component includes: amplifier U1A; The inverting input terminal of the amplifier U1A is connected to the output terminal of the limiting control component; the non-inverting input terminal of the amplifier U1A is grounded; the output terminal of the amplifier U1A is connected to the input terminal of the limiting control component. When the audio input signal is transmitted to the audio amplification component, the audio input signal is input from the inverting input terminal of the amplifier U1A, the limiting signal of the limiting control component is transmitted to the inverting input terminal of the amplifier U1A, and the audio output signal is output from the output terminal of the amplifier U1A.

8. The circuit according to claim 7, characterized in that, The audio amplification component includes: resistor R1, resistor R2, and resistor R3; One end of resistor R2 is connected to one end of resistor R3 and the output terminal of the limiting control component; the other end of resistor R3 is connected to one end of resistor R1 and the inverting input terminal of amplifier U1A; the other end of resistor R1 is connected to the output terminal of amplifier U1A and the input terminal of the limiting control component. When the audio input signal is transmitted to the audio amplification component, the audio input signal is input from the other end of the resistor R2, and the feedback signal of the output terminal of the amplifier U1A is transmitted to the inverting input terminal of the amplifier U1A through the resistor R1.

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