Audio control circuit and bluetooth device

Abstract

The scheme discloses an audio control circuit and a Bluetooth device, which comprise a first feedback module, a second feedback module, an amplification module and a matching module. The matching module is arranged between the first feedback module, the second feedback module and an audio playing module connected with the circuit. The amplification module amplifies the received audio signal, and sends the output audio signal after amplification to the audio playing module connected with the circuit. The first feedback module feeds back the first output audio signal of the first output end of the amplification module to the first input end of the amplification module. The second feedback module feeds back the second output audio signal of the second output end of the amplification module to the second input end of the amplification module. The matching module makes the difference between the target parameters of the first output audio signal and the second output audio signal input to the amplification module less than a threshold value. The bottom noise of the audio playing module can be reduced, and the anti-interference capability of the Bluetooth device is improved.

Description

Technical Field

[0001] This application relates to electronic technology, and to, but is not limited to, an audio control circuit and a Bluetooth device. Background Technology

[0002] With the development of Bluetooth technology, the trends of intelligence and wireless connectivity have been deeply reflected in Bluetooth products. As Bluetooth products become more compactly stacked and the power of Bluetooth operation increases, radio frequency interference with audio modules is gradually becoming apparent, and noise issues such as current hum are becoming increasingly challenging.

[0003] Therefore, how to reduce the noise of Bluetooth devices is an urgent problem to be solved. Summary of the Invention

[0004] In view of this, the audio control circuit and Bluetooth device provided in this application embodiment can reduce the background noise of the audio playback module and improve the anti-interference capability and user experience of the Bluetooth device. The audio control circuit and Bluetooth device provided in this application embodiment are implemented as follows:

[0005] In a first aspect, embodiments of this application provide an audio control circuit, the circuit including a first feedback module, a second feedback module, an amplification module, and a matching module, wherein the first feedback module and the second feedback module are respectively connected in parallel with the amplification module, and the matching module is disposed between the first feedback module, the second feedback module, and an audio playback module connected to the circuit, wherein:

[0006] The amplification module is used to amplify the received audio signal and send the amplified output audio signal to the audio playback module.

[0007] The first feedback module is used to feed back the first output audio signal from the first output terminal of the amplification module to the first input terminal of the amplification module;

[0008] The second feedback module is used to feed back the second output audio signal from the second output terminal of the amplification module to the second input terminal of the amplification module;

[0009] The output audio signal includes the first output audio signal and the second output audio signal;

[0010] The matching module is configured to ensure that the difference between the target parameters of the first output audio signal and the second output audio signal input to the amplification module is less than a threshold, wherein the target parameters include amplitude and / or phase.

[0011] Secondly, embodiments of this application provide a Bluetooth device, including an audio control circuit.

[0012] The audio control circuit and Bluetooth device provided in this application embodiment, by adding a matching module to the audio control circuit, the matching module is set between the first feedback module, the second feedback module and the audio playback module connected to the circuit, so that the difference in amplitude and / or phase between the first output audio signal input to the amplification module via the feedback module and the second output audio signal is less than a threshold, thereby effectively reducing the background noise and improving the anti-interference capability and user experience of the Bluetooth device. Attached Figure Description

[0013] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with this application and, together with the specification, serve to explain the technical solutions of this application.

[0014] Figure 1 This is a schematic diagram illustrating the effect of an earphone provided in an embodiment of this application;

[0015] Figure 2 An impedance characteristic curve of each magnetic bead is provided for an embodiment of this application;

[0016] Figure 3 This is a schematic diagram of the structure of an audio control circuit provided in an embodiment of this application;

[0017] Figure 4 This is a schematic diagram of another audio control circuit provided in an embodiment of this application;

[0018] Figure 5 This is a schematic diagram of the structure of another audio control circuit provided in an embodiment of this application;

[0019] Figure 6 This is a schematic diagram of another audio control circuit provided in an embodiment of this application;

[0020] Figure 7 This is a schematic diagram of the structure of an audio control circuit provided in an embodiment of this application;

[0021] Figure 8 This is a schematic diagram of another audio control circuit provided in an embodiment of this application;

[0022] Figure 9 This is a schematic diagram of another audio control circuit provided in an embodiment of this application. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the specific technical solutions of this application will be further described in detail below with reference to the accompanying drawings of the embodiments of this application. The following embodiments are used to illustrate this application, but are not intended to limit the scope of this application.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0025] In the following description, references are made to “some embodiments,” which describe a subset of all possible embodiments. However, it is understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0026] It should be noted that the terms "first, second, third" used in the embodiments of this application are used to distinguish similar or different objects and do not represent a specific order of objects. It can be understood that "first, second, third" can be interchanged in a specific order or sequence where permitted, so that the embodiments of this application described herein can be implemented in an order other than that illustrated or described herein.

[0027] With the development of Bluetooth technology, the trends of intelligence and wireless connectivity have been deeply reflected in Bluetooth products. As Bluetooth products become more compactly stacked and the power of Bluetooth operation increases, radio frequency interference with audio modules is gradually becoming apparent, and noise issues such as current hum are becoming increasingly challenging.

[0028] Figure 1 Provide a schematic diagram of the effect of one type of headphone. For example... Figure 1 As shown, the left and right earbuds of TWS earbuds do not require a cable connection and can work independently by wirelessly separating the left and right channels. This completely eliminates the hassle of wires, making exercise more free; the usage is also more versatile, allowing for solo use, sharing, or even using one device as two.

[0029] TWS earbuds have two metal pins at the bottom, called spring pins. When the earbuds are placed in the charging case, they enable the circuit between the earbuds and the charging case to conduct, thus fulfilling the charging and communication functions of the earbuds.

[0030] Typical TWS earbuds have two or three POGO PINs, located in corresponding positions on the earbuds and charging case. When the earbuds are placed in the charging case, the POGO PINs on the earbuds and the charging case will make contact and conduct electricity.

[0031] The charging case serves to store and charge the earbuds. When not in use, the portable charging case can be used to store and charge the earbuds. Typically, the earbuds are placed inside the charging case, where they are magnetically secured in place, and the case then begins charging.

[0032] In Bluetooth devices such as Bluetooth headsets, noise is often audible, which is often referred to as background noise. There are two main sources of this noise: electrical hum and white noise. Electrical hum primarily originates from interference from electronic components such as power inductors and batteries; while white noise is mainly related to the chip itself.

[0033] As Bluetooth devices become increasingly compact and their operating power increases, radio frequency interference with the audio modules within these devices is becoming more apparent, making the issue of hum increasingly challenging.

[0034] For the audio module of a Bluetooth chip, in order to ensure its performance (such as power consumption, sound quality, noise floor, etc.), the internal power amplifier module (PA) operates differently depending on whether the input audio signal is a high-volume signal or a low-volume signal.

[0035] When the input audio signal is a low-frequency signal, the power amplifier (PA) reduces its internal drive current during low-signal conditions to lower power consumption, causing the transistor to operate in the subthreshold or weak inversion region. At this time, the PA's transconductance (gm) decreases, the gain decreases, but the power consumption drops significantly. The reduced drive current leads to an increase in the PA's output impedance, resulting in poorer matching with the speaker (SPK). Radio frequency interference (such as 2.4GHz Bluetooth signals) can easily couple into the audio path through parasitic capacitance, causing noise (such as current noise).

[0036] In related technologies, a common method to solve this problem is to string a ferrite bead in the SPK path. The audio ferrite bead weakens the radio frequency interference of Bluetooth 2.4G and prevents it from entering the audio module of the Bluetooth chip.

[0037] However, connecting an inductor or ferrite bead in series in the SPK path will attenuate the audio signal due to its resistive and capacitive characteristics, which will affect the sound quality.

[0038] Figure 2 The impedance characteristic curves of various magnetic beads are given. For example... Figure 2 As shown, ferrite beads possess resistive-capacitive-inductive characteristics. Although their impedance is relatively low, it still affects sound quality. Currently, Direct Current Resistance (DCR) is a crucial parameter for selecting audio ferrite beads; that is, the resistance value exhibited by electronic components under direct current conditions is a key factor in choosing audio ferrite beads. Ferrite beads can currently achieve impedances of several hundred mΩ, but further reduction is difficult due to manufacturing limitations. Furthermore, ferrite beads can affect signal distortion, thus impacting sound quality. Additionally, ferrite beads are relatively expensive, increasing the overall cost of the device.

[0039] In view of this, embodiments of this application provide an audio control circuit that can be applied to Bluetooth devices. Bluetooth devices may include, but are not limited to, headphones, speakers, and music lights.

[0040] Figure 3 This is a schematic diagram of an audio control circuit provided in an embodiment of this application.

[0041] like Figure 3 As shown, the audio control circuit includes a first feedback module, a second feedback module, an amplification module, and a matching module. The first feedback module and the second feedback module are connected in parallel with the amplification module, and the matching module is located between the first feedback module, the second feedback module, and the audio playback module connected to the circuit.

[0042] In this embodiment of the application, the amplification module is used to amplify the received audio signal and send the amplified output audio signal to the audio playback module connected to the audio control circuit.

[0043] In this embodiment of the application, the amplification module may be a power amplifier PA. In an audio system, the power amplifier PA can amplify the received audio signal to a degree sufficient to drive the audio playback module (such as a speaker) to emit sound.

[0044] The first feedback module is used to feed back the first output audio signal from the first output terminal of the amplification module to the first input terminal of the amplification module.

[0045] The second feedback module is used to feed back the second output audio signal from the second output terminal of the amplification module to the second input terminal of the amplification module.

[0046] The output audio signal includes a first output audio signal and a second audio signal.

[0047] like Figure 3 As shown, in some embodiments, the first feedback module FB1 may be the feedback network corresponding to the positive terminal (SPK_P) of the audio playback module, and the second feedback module FB2 may be the feedback network corresponding to the negative terminal (SPK_N) of the audio playback module.

[0048] Thus, when the interference signal is transmitted to the input of the power amplifier (PA) through the feedback network (FB1 and FB2), the trace lengths from SPK_P and SPK_N to the interference source are often different in actual circuit design. According to the principle of electromagnetic wave propagation, signal propagation on transmission lines is delayed, and the longer the trace, the more opportunities for electromagnetic interference coupling. For example, if the trace of SPK_P is much longer than that of SPK_N, then SPK_P is more susceptible to interference from surrounding electromagnetic fields during transmission, thus introducing more interference signals and causing the interference experienced by the two to be inconsistent.

[0049] Alternatively, in a compact circuit layout, it may not be possible to guarantee that the traces of SPK_P and SPK_N have a completely symmetrical environment. For example, in a multilayer circuit board, the trace of SPK_P may be located on a layer with higher interference, while the trace of SPK_N may be located on a layer with lower interference; or the distribution of other components around them may be different, resulting in different electromagnetic shielding effects and thus inconsistent interference.

[0050] These factors can cause differences in the interference signals transmitted to the PA input.

[0051] In addition, there are nonlinear devices inside the PA. These nonlinear devices will detect inconsistent interference signals, thereby generating low-frequency envelope (DC) signals, which will ultimately manifest as noise.

[0052] Based on this, in the embodiments of this application, by setting a matching module between the first feedback module, the second feedback module and the audio playback module connected to the circuit, the difference between the target parameters of the first output audio signal and the second output audio signal can be made less than a threshold. The target parameters include amplitude and / or phase.

[0053] Figure 4 This is a schematic diagram of an audio control circuit provided in an embodiment of this application.

[0054] like Figure 4 As shown, the matching module is an adjustment module. When the adjustment module forms a loop with the audio playback module, the difference between the target parameters of the first output audio signal and the second output audio signal is less than a threshold.

[0055] In other words, the adjustment module is connected to the two output terminals of the amplification module, such as... Figure 4 As shown, after the adjustment module is connected in parallel across SPK_P and SPK_N, the audio playback module and the adjustment module form a loop. This loop provides an additional path for interference signals, allowing them to be better balanced between SPK_P and SPK_N. Ideally, it can eliminate interference signals; even if it cannot completely eliminate them, it can reduce the amplitude and / or phase difference between the first and second output audio signals transmitted to both ends of the PA, thereby reducing the detection effect caused by the nonlinear devices inside the PA and reducing noise.

[0056] In this embodiment, the audio control circuit may be part of the Bluetooth chip, and the adjustment module may be located inside or outside the Bluetooth chip, with no limitation on the specific installation location.

[0057] In some embodiments, the adjustment module is a resistor or an inductor.

[0058] In some embodiments, when the adjustment module is a resistor, the value of the resistor can be determined based on parameters that affect the audio performance of the audio control circuit.

[0059] Here, parameters affecting the audio performance of the audio control circuit may include one or more of the following: the gain coefficient of the amplification module, the length of the connection line between the adjustment module and the audio playback module, the impedance and frequency response of the audio playback module.

[0060] When the adjustment module is a resistor, its value should match the rated impedance of the audio playback module to ensure that it does not excessively affect the amplitude and phase of the audio signal during normal audio signal transmission. Generally, the resistance value of the adjustment module should be greater than the rated impedance of the audio playback module to avoid excessive shunting of the audio signal.

[0061] Furthermore, when selecting the value of the adjustment module, its impedance stability within the audio frequency range needs to be considered to ensure that interference signals can be effectively balanced throughout the entire audio frequency band.

[0062] In some embodiments, the value of the adjustment module may also take into account the frequency and amplitude of the interference signal. For example, for high-frequency interference signals, a smaller resistor value may be needed to provide a lower impedance path for better guidance of the interference signal; while for low-frequency interference signals, a larger resistor value may be sufficient. If the interference signal amplitude is large, a smaller resistor value may be needed to ensure sufficient signal shunting, thereby effectively reducing the interference difference transmitted to the PA input.

[0063] In this embodiment, by adding an adjustment module to the audio control circuit, the adjustment module is connected to the two input terminals of the amplification module, thereby enabling the adjustment module to form a loop with the audio playback module. This ensures that the difference in amplitude and / or phase between the first output audio signal input to the amplification module via the feedback module and the second output audio signal is less than a threshold, thereby effectively reducing background noise and improving the anti-interference capability and user experience of the Bluetooth device.

[0064] Figure 5 This is a schematic diagram of an audio control circuit provided in an embodiment of this application.

[0065] like Figure 5 As shown, in Figure 4 Based on the given audio control circuit, the audio control circuit also includes a first switching circuit, which is connected to the adjustment module, and the audio control circuit is also connected to the control module.

[0066] In this way, the control module can be used to control the first switching circuit to be in a connected state, so that the adjustment module and the audio playback module form a loop, and the difference in amplitude and / or phase between the first output audio signal and the second output audio signal input to both ends of the amplification module is less than a threshold.

[0067] Here, the first switching circuit can be a field-effect transistor (FET) or a bipolar junction transistor (BJT), wherein the field-effect transistor includes a metal oxide semiconductor field-effect transistor (MOS FET) and a junction field-effect transistor (JFET).

[0068] It should be noted that the specific types of switching circuits mentioned above are merely illustrative examples. The embodiments of this application do not limit the specific types of switching circuits, and any device with switching circuit function is applicable to the circuits provided in this application.

[0069] Figure 6 This is a schematic diagram of an audio control circuit provided in an embodiment of this application.

[0070] like Figure 6 As shown, in Figure 5 Based on the given audio control circuit, the audio control circuit is connected to the detection module.

[0071] The detection module is used to detect the voltage amplitude and / or signal power of the audio signal and send the voltage amplitude and / or signal power to the control module connected to the circuit.

[0072] It should be noted that in audio control circuits, the detection of the volume of an audio signal is usually based on the measurement and analysis of specific physical quantities of the signal. In essence, the volume is characterized by detecting parameters such as the amplitude, power, energy, or sample value of the digital audio signal.

[0073] For example, in analog audio signal processing, volume is directly related to the amplitude of the signal. The larger the signal amplitude, the louder the sound perceived by the human ear. Therefore, volume can be characterized by detecting the voltage amplitude of the audio signal.

[0074] Alternatively, the power of an audio signal is also closely related to its volume. The greater the power, the more energy the signal carries, and the louder the sound produced.

[0075] Based on this, in some embodiments, the voltage amplitude and / or signal power of the audio signal can be detected by the detection module to determine the audio level of the audio signal.

[0076] Of course, in digital audio systems, audio signals are sampled and quantized into digital signals. Each sample point has a corresponding digital value, which reflects the amplitude of the signal at that moment. By analyzing the sampled values ​​over a period of time, the volume of the signal can be calculated.

[0077] Alternatively, digital audio signals are typically processed in multiple frames, each containing a certain number of sampling points. By calculating the energy of each frame's signal, the intensity of the audio signal within that frame can be reflected, thus characterizing the volume.

[0078] Therefore, in some embodiments, the volume of the audio signal can also be determined by the detection module in the manner described above, without limitation.

[0079] In some embodiments, the detection module may be an application processor (AP) or a digital signal processor (DSP), which can analyze the voltage amplitude or signal power of the received audio signal to evaluate the volume of the audio signal.

[0080] In some embodiments, the detection module may also be a digital volume control register, and the volume of the currently input audio signal can be indirectly obtained by reading the value of the digital volume register.

[0081] The control module can control the first switching circuit to be in a connected state when the received voltage amplitude is less than the voltage threshold and / or the signal power is less than the power threshold, so that the adjustment module and the audio playback module form a loop, and the difference in amplitude and / or phase between the first output audio signal and the second output audio signal input to both ends of the amplification module is less than the threshold.

[0082] It should be noted that in some embodiments, it is not necessary to perform the step of the detection module detecting the voltage amplitude and / or signal power of the audio signal to determine the volume of the audio signal. In this way, regardless of whether the input audio signal is a high-volume signal or a low-volume signal, the loop between the adjustment module and the audio playback module can be connected, so that the difference in amplitude and / or phase between the first output audio signal and the second output audio signal input to both ends of the amplification module is less than the threshold, thereby reducing the background noise.

[0083] However, it is understandable that when the audio signal is a high-volume signal, due to the large operating current inside the PA, its strong anti-interference capability, and the adjustment of the feedback network, and because the audio signal is much larger than the interference signal, the impact of interference on the audio system becomes smaller. Therefore, in some embodiments, if the volume of the audio signal is greater than a threshold, the loop between the adjustment module and the audio playback module can be disconnected.

[0084] By implementing this embodiment, the loop between the adjustment module and the audio playback module can be reconnected when the input audio signal is a low-volume signal. This effectively reduces the background noise when the input audio signal is a low-volume signal, improving the device's anti-interference capability.

[0085] Figure 7 This is a schematic diagram of an audio control circuit provided in an embodiment of this application.

[0086] like Figure 7 As shown, the matching module may include a second switching circuit and a third switching circuit.

[0087] The second switching circuit is connected between the first feedback module and the audio playback module, and the third switching circuit is connected between the second feedback module and the audio module.

[0088] The detection module is used to detect the voltage amplitude and / or signal power of the audio signal and send the voltage amplitude and / or signal power to the control module connected to the circuit.

[0089] The control module is used to control the second and third switching circuits to be in an open state when the received voltage amplitude is less than a voltage threshold and / or the signal power is less than a power threshold.

[0090] In this way, when the input audio signal is determined to be a low-volume audio signal, the control module can also control the first feedback module and the second feedback to be in a closed state. In this way, the interference signal cannot be directly transmitted to the input end of the amplification module, so that the difference in amplitude and / or phase between the first output audio signal and the second output audio signal can be less than the threshold, thereby effectively reducing the background noise and improving the anti-interference capability of the Bluetooth device.

[0091] Understandably, if the feedback gain of the feedback module is too large, the feedback signal may overwrite the original audio signal, causing the nonlinear devices inside the PA (such as transistors) to produce a detection effect, generating a low-frequency envelope (DC) signal, which will cause noise.

[0092] Therefore, in some embodiments, the feedback gain of the first feedback module and the second feedback module can be reduced so that the difference in amplitude and / or phase between the first output audio signal input to the amplification module and the second output audio signal can be less than a threshold, thereby effectively reducing the background noise and improving the anti-interference capability of the Bluetooth device.

[0093] In some embodiments, where the matching module includes a second switching circuit and a third switching circuit, such as Figure 4 As shown, an adjustment module can still be connected between the two output terminals of the amplification module and the audio playback module. That is, a resistor can still be connected between the two output terminals of the amplification module and the audio playback module, so that the resistor and the audio playback module form a loop, in order to further reduce the difference of the target parameter between the first output audio signal and the second output audio signal.

[0094] Implementing this embodiment significantly reduces the background noise of Bluetooth devices, making the played audio more comfortable to listen to and improving the user experience.

[0095] Figure 8 This is a schematic diagram of an audio control circuit provided in an embodiment of this application.

[0096] like Figure 8 As shown, the audio control circuit also includes a second capacitor, one end of which is connected to the first feedback module or the second feedback module, and the other end of which is connected to ground.

[0097] In this way, by connecting a second capacitor in parallel with the first feedback module and / or the second feedback module, the characteristics of the capacitor in blocking DC and passing AC and storing energy and filtering can be utilized. That is, it presents high impedance (equivalent to an open circuit) for DC signals and low impedance (equivalent to a short circuit) for AC signals, thereby causing a short circuit to high-frequency interference signals.

[0098] In other words, the frequency of high-frequency interference signals is much higher than that of audio signals, and the capacitor presents extremely low impedance to them. In this way, the interference signals flow directly to the ground through the capacitor, avoiding entering the input terminal of the amplifier module.

[0099] The capacitance value of the first capacitor can be selected based on the interference frequency and circuit impedance.

[0100] It should be noted that, if a matching module is already included in the audio control circuit, a second capacitor can be further introduced to reduce the amplitude and / or phase difference between the input to the first output audio signal and the second output audio signal through the combined action of the matching module and the second capacitor. Alternatively, either the matching module or the second capacitor can be used alone; there is no limitation on this.

[0101] By implementing this embodiment, by connecting capacitors in parallel to the first feedback module and / or the second feedback module, interference signals can flow directly to the ground through the capacitors, avoiding entering the input of the amplification module. This ensures that the difference in amplitude and / or phase between the first output audio signal and the second output audio signal is less than a threshold, thereby effectively reducing the background noise and improving the anti-interference capability of the Bluetooth device.

[0102] Figure 9 This is a schematic diagram of an audio control circuit provided in an embodiment of this application.

[0103] like Figure 9 As shown, the audio control circuit also includes a first capacitor, which is connected in parallel with the first feedback module and / or the second feedback module.

[0104] In this way, by connecting the first capacitor in parallel across the first feedback module and / or the second feedback module, the characteristics of the capacitor in blocking DC and passing AC and storing energy and filtering can be utilized. That is, it presents high impedance (equivalent to an open circuit) for DC signals and low impedance (equivalent to a short circuit) for AC signals, thereby causing a short circuit to high-frequency interference signals.

[0105] In other words, the frequency of high-frequency interference signals is much higher than that of audio signals, and the capacitor presents extremely low impedance to them. In this way, the interference signals flow directly to another path through the capacitor, avoiding entering the input terminal of the amplifier module.

[0106] The capacitance value of the first capacitor can be selected based on the interference frequency and circuit impedance.

[0107] It should be noted that, if a matching module is already included in the audio control circuit, a first capacitor can be further introduced to reduce the amplitude and / or phase difference between the input to the first output audio signal and the second output audio signal through the combination of the matching module and the first capacitor. Alternatively, either the matching module or the first capacitor can be used alone; there is no limitation on this.

[0108] By implementing this embodiment, by connecting capacitors in parallel to the first feedback module and / or the second feedback module, interference signals can flow directly to another path through the capacitors, avoiding entering the input terminal of the amplification module. This ensures that the difference in amplitude and / or phase between the first output audio signal and the second output audio signal is less than a threshold, thereby effectively reducing the background noise and improving the anti-interference capability of the Bluetooth device.

[0109] Implementing this embodiment significantly improves the product's performance. It reduces Bluetooth device noise without increasing the distance between the battery and speaker, and avoids the need to increase device size due to distance, thus preventing changes in the device's shape.

[0110] Based on the audio control circuit provided in the above embodiments, this application further provides an audio control method for eliminating background noise generated in the audio control circuit. The method is applied to the audio control circuit provided in the above embodiments and includes the following:

[0111] The voltage amplitude and / or signal power of the input audio signal are detected; if the voltage amplitude is less than a voltage threshold and / or the signal power is less than a power threshold, the first switching circuit connected to the control and adjustment module is in a connected state, so that the adjustment module and the audio playback module form a loop.

[0112] In this way, even when the input audio signal is at a low volume, a loop can be established between the adjustment module and the audio playback module. This loop provides an additional path for interference signals, allowing them to be better balanced between the two input terminals of the amplification module. Ideally, it can eliminate interference signals; even if it cannot completely eliminate them, it can reduce the amplitude and / or phase difference between the first and second output audio signals transmitted to both ends of the amplification module, thereby reducing the detection effect caused by the nonlinear devices inside the amplification module and reducing noise.

[0113] It should be noted that the module division in the embodiments of this application is illustrative and only represents one logical functional division. In actual implementation, there may be other division methods. Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, exist as separate physical units, or have two or more units integrated into one unit. The integrated units can be implemented in hardware, as software functional units, or a combination of software and hardware.

[0114] This application provides a Bluetooth device, which refers to a device with audio playback function, such as headphones, speakers, music lights, etc.

[0115] It should be understood that the phrases "one embodiment," "an embodiment," or "some embodiments" mentioned throughout the specification mean that a specific feature, structure, or characteristic related to an embodiment is included in at least one embodiment of this application. Therefore, "in one embodiment," "in one embodiment," or "in some embodiments" appearing throughout the specification do not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. It should be understood that in the various embodiments of this application, the sequence numbers of the above-described processes do not imply a sequential order of execution; the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application. The sequence numbers of the above-described embodiments are merely for descriptive purposes and do not represent the superiority or inferiority of the embodiments. The descriptions of the various embodiments above tend to emphasize the differences between the various embodiments; their similarities or commonalities can be referred to mutually, and for the sake of brevity, they will not be repeated here.

[0116] In this article, the term "and / or" is merely a description of the relationship between related objects, indicating that there can be three kinds of relationships. For example, object A and / or object B can represent three situations: object A exists alone, object A and object B exist simultaneously, and object B exists alone.

[0117] In the several embodiments provided in this application, it should be understood that the disclosed device can be implemented in other ways. The embodiments described above are merely illustrative. For example, the division of modules is only a logical functional division, and in actual implementation, there may be other division methods, such as: multiple modules or components can be combined, or integrated into another system, or some features can be ignored or not executed. In addition, the coupling, direct coupling, or communication connection between the various components shown or discussed can be through some interfaces, and the indirect coupling or communication connection between devices or modules can be electrical, mechanical, or other forms.

[0118] The modules described above as separate components may or may not be physically separate. The components shown as modules may or may not be physical modules. They may be located in one place or distributed across multiple network units. Some or all of the modules may be selected to achieve the purpose of this embodiment according to actual needs.

[0119] In addition, each functional module in the various embodiments of this application can be integrated into one processing unit, or each module can be a separate unit, or two or more modules can be integrated into one unit; the integrated modules can be implemented in hardware or in the form of hardware plus software functional units.

[0120] The above description is merely an embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An audio control circuit, characterized in that, The audio control circuit includes a first feedback module, a second feedback module, an amplification module, and a matching module. The first feedback module and the second feedback module are connected in parallel with the amplification module, respectively. The matching module is disposed between the first feedback module, the second feedback module, and the audio playback module connected to the audio control circuit. The amplification module is used to amplify the received audio signal and send the amplified output audio signal to the audio playback module. The first feedback module is used to feed back the first output audio signal from the first output terminal of the amplification module to the first input terminal of the amplification module; The second feedback module is used to feed back the second output audio signal from the second output terminal of the amplification module to the second input terminal of the amplification module; The output audio signal includes the first output audio signal and the second output audio signal; The matching module is configured to ensure that the difference between the target parameters of the first output audio signal and the second output audio signal input to the amplification module is less than a threshold, wherein the target parameters include amplitude and / or phase. The audio control circuit further includes a first switching circuit, which is connected to the matching module. The audio control circuit is also connected to the control module, wherein: The control module is used to control the first switching circuit to be in a connected state so that the matching module and the audio playback module form a loop; The audio control circuit is connected to the detection module, which is used to detect the voltage amplitude and / or signal power of the received audio signal and send the voltage amplitude and / or signal power to the control module connected to the audio control circuit. The control module is used to control the first switching circuit to be in a connected state when the voltage amplitude is less than the voltage threshold and / or the signal power is less than the power threshold, so that the matching module and the audio playback module form a loop.

2. The audio control circuit according to claim 1, characterized in that, The matching module is an adjustment module. When the adjustment module forms a loop with the audio playback module, the difference between the target parameters of the first output audio signal and the second output audio signal is less than a threshold.

3. The audio control circuit according to claim 2, characterized in that, The adjustment module is a resistor or an inductor.

4. The audio control circuit according to claim 2 or 3, characterized in that, The value of the adjustment module is determined based on the parameters that affect the audio performance of the audio control circuit.

5. The audio control circuit according to claim 4, characterized in that, The parameters affecting the audio performance of the audio control circuit include one or more of the following: the gain coefficient of the amplification module, the length of the connection line between the adjustment module and the audio playback module, the length of the connection line between the amplification module and the audio playback module, the impedance and frequency response of the audio playback module.

6. The audio control circuit according to claim 1, characterized in that, The matching module includes a second switching circuit and a third switching circuit. The second switching circuit is connected between the first feedback module and the audio playback module, and the third switching circuit is connected between the second feedback module and the audio playback module, wherein: The control module is used to control the second switching circuit and the third switching circuit to be in an open state when the voltage amplitude is less than the voltage threshold and / or the signal power is less than the power threshold.

7. The audio control circuit according to claim 1, characterized in that, The audio control circuit further includes a first capacitor, which is connected in parallel with the first feedback module and / or the first capacitor is connected in parallel with the second feedback module.

8. The audio control circuit according to claim 1, characterized in that, The audio control circuit further includes a second capacitor, one end of which is connected to the first feedback module or the second feedback module, and the other end of which is connected to ground.

9. A Bluetooth device, characterized in that, Includes the audio control circuit as described in any one of claims 1 to 8.

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