Audio link and vehicle-mounted audio equipment

Abstract

The embodiment of the invention discloses an audio link and vehicle-mounted audio equipment, and belongs to the field of audio processing. The audio link comprises a tuning circuit, a digital signal processor, a power amplifier circuit, a distortion detection circuit and a system chip; the digital signal processor is connected with the input end of the system chip through the power amplifier circuit and the distortion detection circuit in sequence, the output end of the system chip is connected with the control end of the digital signal processor, and the tuning circuit is connected with the input end of the digital signal processor. Under the condition that the vehicle-mounted audio equipment is not integrated with an audio processing chip, various functions of high-efficiency audio signal processing, distortion detection and tone tuning can be realized on the premise of low cost by connecting the audio link, and the audio function of the vehicle-mounted audio equipment is prevented from being limited.

Description

Technical Field

[0001] The present invention relates to the field of audio processing, and particularly to an audio link and an in-vehicle audio device. Background Art

[0002] With the continuous development of in-vehicle systems, automobiles have gradually evolved from a single means of transportation to a mobile intelligent terminal. Users' demands for automobiles are not limited to power performance and mechanical quality, but also require a more comfortable intelligent cockpit environment and a more excellent intelligent interaction experience. For the intelligent cockpit of a vehicle, audio devices are an important part of enhancing the user experience, and it is required that in-vehicle audio devices have efficient audio signal processing capabilities to provide users with high-quality audio experiences.

[0003] Existing in-vehicle audio devices usually use highly integrated audio processing chips to implement audio processing functions such as distortion detection and tuning. However, due to the high cost of highly integrated audio processing chips, the audio functions of in-vehicle audio devices are limited, and it is impossible to provide efficient distortion detection functions and tuning functions on the premise of low cost. In addition, due to the high integration of audio processing chips, in the case where an in-vehicle audio device does not have an audio processing chip pre-integrated, it will cause the in-vehicle audio device to be unable to provide distortion detection functions and tuning functions, thereby limiting the audio functions of the in-vehicle audio device. Summary of the Invention

[0004] The purpose of the embodiments of the present invention is to provide an audio link and an in-vehicle audio device for solving the problem that the audio functions of in-vehicle audio devices are limited.

[0005] To achieve the above purpose, in a first aspect, the present application provides an audio link, which includes a tuning circuit, a digital signal processor, a power amplifier circuit, a distortion detection circuit, and a system chip;

[0006] The digital signal processor is sequentially connected to the input end of the system chip through the power amplifier circuit and the distortion detection circuit, the output end of the system chip is connected to the control end of the digital signal processor, and the tuning circuit is connected to the input end of the digital signal processor;

[0007] The tuning circuit is configured to input a tuning signal to the digital signal processor when the audio link is in a tuning mode;

[0008] The power amplifier circuit is configured to convert the digital audio signal output by the digital signal processor into a power amplifier signal to be output;

[0009] The distortion detection circuit is configured to generate a detection signal when the signal of the power amplifier circuit is distorted;

[0010] A system-on-chip for outputting a control signal to a digital signal processor when a detection signal is generated by a distortion detection circuit;

[0011] A digital signal processor for adjusting the gain of a digital audio signal according to a received control signal.

[0012] In an embodiment of the present application, the audio link includes an analog signal processing circuit;

[0013] The output end of the analog signal processing circuit is connected to the input end of the digital signal processor;

[0014] An analog signal processing circuit for converting a received analog audio signal into a digital audio signal and outputting the digital audio signal to the digital signal processor.

[0015] In an embodiment of the present application, the audio link further includes a first analog switch and a second analog switch;

[0016] The first analog switch is connected to the digital signal processor through the analog signal processing circuit, the system-on-chip is connected to the digital signal processor through the second analog switch, and the tuning circuit is connected to the node between the first analog switch and the analog signal processing circuit;

[0017] The first analog switch and the second analog switch are used to remain disconnected when the audio link is in the tuning mode.

[0018] In an embodiment of the present application, the analog signal processing circuit includes at least two audio signal processing sub-circuits, and each audio signal processing sub-circuit includes an operational amplifier, a low-pass filter, and a high-pass filter;

[0019] The low-pass filter includes a first capacitor and a first resistor, and the high-pass filter includes a second capacitor and an analog-to-digital converter;

[0020] The output end of the operational amplifier is grounded through the first capacitor and the first resistor in sequence, and the first capacitor and the first resistor are also connected to the analog-to-digital converter through the second capacitor;

[0021] The first input end and the second input end of the operational amplifier are both used to connect to an audio input device.

[0022] In an embodiment of the present application, the analog signal processing circuit includes a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, and a seventh resistor;

[0023] One end of the second resistor is used to connect to a control power supply, the other end of the second resistor is grounded through the third resistor, one end of the fifth resistor is used to connect to an audio input device, the other end of the fifth resistor is connected to the node between the second resistor and the third resistor through the fourth resistor, and the first input end of the operational amplifier is connected to the node between the fourth resistor and the fifth resistor;

[0024] One end of the sixth resistor is used to connect to an audio input device, and the other end of the sixth resistor is connected to the output end of the operational amplifier through the seventh resistor. The second input end of the operational amplifier is connected to the node between the sixth resistor and the seventh resistor.

[0025] In an embodiment of the present application, the audio link further includes a microcontroller;

[0026] The distortion detection circuit is connected to the system chip through the microcontroller;

[0027] The microcontroller is configured to output an interaction signal to the system chip when the distortion detection circuit generates a detection signal;

[0028] The system chip is configured to output a control signal to the digital signal processor according to the received interaction signal.

[0029] In an embodiment of the present application, the power amplifier circuit includes a first power amplifier chip and a second power amplifier chip, and the distortion detection circuit includes a first voltage comparator and a second voltage comparator;

[0030] The clip pin of the first power amplifier chip is connected to the first input end of the first voltage comparator, and the output end of the first voltage comparator is connected to the first input end of the microcontroller;

[0031] The clip pin of the second power amplifier chip is connected to the first input end of the second voltage comparator, and the output end of the second voltage comparator is connected to the second input end of the microcontroller;

[0032] The second input end of the first voltage comparator and the second input end of the second voltage comparator are both connected to the signal output end of the microcontroller;

[0033] The microcontroller is further configured to output a reference audio signal to the first voltage comparator and the second voltage comparator respectively.

[0034] In an embodiment of the present application, the distortion detection circuit further includes a first voltage-dividing resistor, a second voltage-dividing resistor, a third voltage-dividing resistor, a fourth voltage-dividing resistor, a fifth voltage-dividing resistor, a sixth voltage-dividing resistor, a third capacitor in parallel with the first voltage-dividing resistor, a fourth capacitor in parallel with the fourth voltage-dividing resistor, and a fifth capacitor in parallel with the sixth voltage-dividing resistor;

[0035] One end of the first voltage-dividing resistor is used to connect to a control power supply, the other end of the first voltage-dividing resistor is connected to the clip pin of the first power amplifier chip through the second voltage-dividing resistor, and the first input end of the first voltage comparator is connected to the node between the first voltage-dividing resistor and the second voltage-dividing resistor;

[0036] The signal output end of the microcontroller is grounded sequentially through the third voltage-dividing resistor and the fourth voltage-dividing resistor;

[0037] One end of the sixth voltage-dividing resistor is used to connect to the control power supply. The other end of the sixth voltage-dividing resistor is connected to the clip pin of the second power amplifier chip through the fifth voltage-dividing resistor. The first input terminal of the second voltage comparator is connected to the node between the fifth voltage-dividing resistor and the sixth voltage-dividing resistor.

[0038] In an embodiment of the present application, the distortion detection circuit further includes a first pull-up resistor and a second pull-up resistor;

[0039] One end of the first pull-up resistor is connected to the output terminal of the first voltage comparator. The other end of the first pull-up resistor is connected to the output terminal of the second voltage comparator through the second pull-up resistor. The other end of the first pull-up resistor is used to connect to the control power supply.

[0040] In a second aspect, the present application provides a vehicle-mounted audio device, which includes an audio input device, an audio output device, and the above-mentioned audio link;

[0041] The audio input device is connected to the audio output device through the audio link.

[0042] The present application provides an audio link, including: a tuning circuit, a digital signal processor, a power amplifier circuit, a distortion detection circuit, and a system chip; the digital signal processor is sequentially connected to the input terminal of the system chip through the power amplifier circuit and the distortion detection circuit. The output terminal of the system chip is connected to the control terminal of the digital signal processor. The tuning circuit is connected to the input terminal of the digital signal processor. The audio link can detect and adjust the gain in a timely manner when the audio signal is distorted, thereby ensuring the quality of the audio output. In addition, the audio link also has a tuning function, and can adjust the audio signal through the tuning circuit and the digital signal processor. In the case where the vehicle-mounted audio device does not integrate an audio processing chip, by connecting the audio link, it is possible to realize multiple functions of efficient audio signal processing, distortion detection, and tuning at low cost, and avoid the limitation of the audio function of the vehicle-mounted audio device.

[0043] Other features and advantages of the embodiments of the present invention will be described in detail in the subsequent specific implementation part. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The drawings are used to provide a further understanding of the embodiments of the present invention, and constitute a part of the specification. Together with the following specific implementation manners, they are used to explain the embodiments of the present invention, but do not constitute a limitation to the embodiments of the present invention. In the drawings:

[0045] Figure 1 The first structural schematic diagram of the audio link provided by the embodiment of the present application is shown;

[0046] Figure 2 The second structural schematic diagram of the audio link provided by the embodiment of the present application is shown;

[0047] Figure 3 shows a schematic structural diagram of an audio signal processing sub - circuit provided by an embodiment of the present application;

[0048] Figure 4 shows a schematic structural diagram of a distortion detection circuit provided by an embodiment of the present application;

[0049] Figure 5 shows a schematic structural diagram of an in - vehicle audio device provided by an embodiment of the present application.

[0050] Description of Reference Numerals

[0051] 1000 - in - vehicle audio device; 100 - audio link, 200 - audio input device, 300 - audio output device; 110 - tone control circuit, 120 - digital signal processor, 130 - power amplifier circuit, 140 - distortion detection circuit, 150 - system chip, 160 - analog signal processing circuit, 170 - first analog switch, 180 - second analog switch, 190 - microcontroller; 111 - tone control interface, 112 - AUX sub - circuit; U1 - operational amplifier, U2 - first voltage comparator, U3 - second voltage comparator, C1 - first capacitor, C2 - second capacitor, C3 - third capacitor, C4 - fourth capacitor, C5 - fifth capacitor, R11 - first resistor, R12 - second resistor, R13 - third resistor, R14 - fourth resistor, R15 - fifth resistor, R16 - sixth resistor, R17 - seventh resistor, R21 - first voltage - dividing resistor, R22 - second voltage - dividing resistor, R23 - third voltage - dividing resistor, R24 - fourth voltage - dividing resistor, R25 - fifth voltage - dividing resistor, R26 - sixth voltage - dividing resistor, R27 - first pull - up resistor, R28 - second pull - up resistor, ADC - analog - to - digital converter, AMP1 - first power amplifier chip, AMP2 - second power amplifier chip. Detailed Embodiments

[0052] Next, the specific embodiments of the present invention will be described in detail with reference to the accompanying drawings in the embodiments of the present invention. It should be understood that the specific embodiments described herein are only for explaining and illustrating the embodiments of the present invention, and are not used to limit the embodiments of the present invention.

[0053] Generally, the components of the embodiments of the present invention described and illustrated in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0054] In the following text, the terms "comprising", "having" and their cognates that can be used in various embodiments of the present invention are only intended to indicate specific features, numbers, steps, operations, elements, components or combinations of the foregoing items, and should not be construed as precluding the existence of one or more other features, numbers, steps, operations, elements, components or combinations of the foregoing items or as precluding the possibility of adding one or more features, numbers, steps, operations, elements, components or combinations of the foregoing items.

[0055] In addition, the terms "first", "second", "third", etc. are only used for distinguishing descriptions and should not be construed as indicating or implying relative importance.

[0056] Unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meaning as commonly understood by those of ordinary skill in the art to which various embodiments of the present invention pertain. The terms (such as those defined in a commonly used dictionary) will be construed to have the same meaning as the contextual meaning in the relevant technical field and will not be construed to have an idealized meaning or an overly formal meaning unless clearly defined in various embodiments of the present invention.

[0057] Please refer to Figure 1 , Figure 1 which shows a first structural schematic diagram of an audio link provided by an embodiment of the present application.

[0058] In an embodiment of the present application, the audio link 100 includes a tone adjustment circuit 110, a digital signal processor 120, a power amplifier circuit 130, a distortion detection circuit 140 and a system chip 150;

[0059] The digital signal processor 120 is sequentially connected to the input end of the system chip 150 through the power amplifier circuit 130 and the distortion detection circuit 140. The output end of the system chip 150 is connected to the control end of the digital signal processor 120, and the tone adjustment circuit 110 is connected to the input end of the digital signal processor 120;

[0060] The tone adjustment circuit 110 is configured to input a tone adjustment signal to the digital signal processor 120 when the audio link 100 is in a tone adjustment mode;

[0061] The power amplifier circuit 130 is configured to convert the digital audio signal output by the digital signal processor 120 into a power amplifier signal to be output;

[0062] The distortion detection circuit 140 is configured to generate a detection signal when the signal of the power amplifier circuit 130 is distorted;

[0063] The system chip 150 is configured to output a control signal to the digital signal processor 120 when the distortion detection circuit 140 generates a detection signal;

[0064] A digital signal processor 120 is configured to adjust the gain of a digital audio signal according to a received control signal.

[0065] When the audio input device 200 obtains an analog audio signal, the analog audio signal is converted into a digital audio signal. Digital Signal Processing (DSP) is used to analyze, transform, and operate on digital signals. In this embodiment, the digital audio signal is processed by the digital signal processor 120 to obtain a processed digital audio signal. The power amplifier circuit 130 is configured to convert the processed digital audio signal output by the digital signal processor 120 into a power amplifier signal to be output, and then the power amplifier signal is converted into a sound signal through the audio output device 300.

[0066] The system-on-chip 150 (SOC) is a technology in which multiple components such as registers and memory of a computer or electronic device are integrated on a single chip. The audio link 100 in this embodiment can provide an audio distortion detection function. Specifically, the distortion detection circuit 140 is configured to analyze the signal of the power amplifier circuit 130 to determine whether signal distortion occurs. When signal distortion occurs in the signal of the power amplifier circuit 130, the distortion detection circuit 140 generates a detection signal. When the distortion detection circuit 140 generates a detection signal, the system-on-chip 150 outputs a control signal to the control terminal of the digital signal processor 120. The digital signal processor 120 adjusts the gain of the digital audio signal according to the received control signal. The audio link 100 can detect and adjust the gain in a timely manner when the audio signal is distorted, thereby ensuring the quality of audio output.

[0067] The audio link 100 in this embodiment can provide a tuning function. Specifically, the tuning circuit 110 is configured to input a tuning signal to the digital signal processor 120 when the audio link 100 is in the tuning mode. The type of the tuning signal is set according to actual requirements and is not limited herein. For ease of understanding, in the embodiments of the present application, the tuning signal is an AUX (Auxiliary) signal to provide an auxiliary audio input signal or output signal through the tuning circuit 110. The audio link 100 also has a tuning function and can adjust the audio signal through the tuning circuit 110 and the digital signal processor 120. When the in-vehicle audio device 1000 does not integrate an audio processing chip, by connecting the audio link 100, it is possible to implement multiple functions of efficient audio signal processing, distortion detection, and tuning at low cost, and avoid limiting the audio function of the in-vehicle audio device 1000.

[0068] Please refer to Figure 2 , Figure 2The second structural schematic diagram of the audio link provided by the embodiment of the present application is shown.

[0069] In the embodiment of the present application, the audio link 100 includes an analog signal processing circuit 160;

[0070] The output end of the analog signal processing circuit 160 is connected to the input end of the digital signal processor 120;

[0071] The analog signal processing circuit 160 is configured to convert the received analog audio signal into a digital audio signal and output the digital audio signal to the digital signal processor 120.

[0072] The analog signal processing circuit 160 is configured to convert the received analog audio signal into a digital audio signal and output the digital audio signal to the digital signal processor 120. For the convenience of understanding, in the embodiment of the present application, the analog signal processing circuit 160 outputs a digital audio signal in TDM (Time Division Multiplexing) format. The digital signal processor 120 performs processing such as gain adjustment and filtering on the digital audio signal to obtain the processed digital audio signal, and outputs the processed digital audio signal to the power amplifier circuit 130.

[0073] In the embodiment of the present application, the audio link 100 further includes a first analog switch 170 and a second analog switch 180;

[0074] The first analog switch 170 is connected to the digital signal processor 120 through the analog signal processing circuit 160, the system chip 150 is connected to the digital signal processor 120 through the second analog switch 180, and the tuning circuit 110 is connected to the node between the first analog switch 170 and the analog signal processing circuit 160;

[0075] The first analog switch 170 and the second analog switch 180 are configured to remain disconnected when the audio link 100 is in the tuning mode.

[0076] For the convenience of understanding, in the embodiment of the present application, the tuning circuit 110 includes an AUX sub-circuit 112 and a tuning interface 111. The tuning interface 111 is connected to the node between the first analog switch 170 and the analog signal processing circuit 160 through the AUX sub-circuit 112, and the tuning interface 111 is also connected to the node between the digital signal processing and the second analog switch 180.

[0077] For ease of understanding, in the embodiments of the present application, the tuning circuit 110 is connected to a conversion board of a PC (Personal Computer), that is, the tuning interface 111 is connected to the conversion board. The conversion board converts the data output by the PC into an SPI (Serial Peripheral Interface) signal, and the SPI signal can control the digital signal processor 120 through the tuning interface 111.

[0078] When the audio link 100 is in the tuning mode, both the first analog switch 170 and the second analog switch 180 are kept open. By opening the first analog switch 170, the path between the audio input device 200 and the audio output device 300 is cut off. By opening the second analog switch 180, the SPI signal path between the system chip 150 and the digital signal processor 120 is cut off. After the AUX signal is output to the analog signal processing circuit 160 through the tuning interface 111 and the AUX sub-circuit 112, it passes through the digital signal processor 120, the power amplifier circuit 130, and the audio output device 300, and then emits the audio for debugging. The PC is connected to the tuning interface 111 through the conversion board for tuning. By opening the first analog switch 170 and the second analog switch 180, signal interference from the audio input device 200 during tuning is avoided.

[0079] In the embodiments of the present application, the analog signal processing circuit 160 includes at least two audio signal processing sub-circuits 112 - AUX, and each audio signal processing sub-circuit 112 - AUX includes an operational amplifier U1, a low-pass filter, and a high-pass filter;

[0080] The low-pass filter includes a first capacitor C1 and a first resistor R11, and the high-pass filter includes a second capacitor C2 and an analog-to-digital converter ADC;

[0081] The output terminal of the operational amplifier U1 is grounded through the first capacitor C1 and the first resistor R11 in sequence, and the first capacitor C1 and the first resistor R11 are also connected to the analog-to-digital converter ADC through the second capacitor C2;

[0082] The first input terminal and the second input terminal of the operational amplifier U1 are both used to connect to the audio input device 200.

[0083] Please refer to Figure 3 , Figure 3 which shows the structural schematic diagram of the audio signal processing sub-circuit provided by the embodiments of the present application.

[0084] Generally, the in-vehicle audio device 1000 includes a left microphone and a right microphone. In this embodiment, a path of audio signal processing sub-circuit 112 - AUX is provided corresponding to the left microphone, and a path of audio signal processing sub-circuit 112 - AUX is provided corresponding to the right microphone. In this embodiment, the low-pass filter includes a first capacitor C1 and a first resistor R11, and the high-pass filter includes a second capacitor C2 and an analog-to-digital converter ADC. The analog-to-digital converter ADC is used to convert the analog audio signal into a digital audio signal. Generally, the maximum sound that the human ear can hear is 20KHZ. In this embodiment, the cut-off frequency of the low-pass filter is 33.88KHZ, and the cut-off frequency of the high-pass filter is 3.7Hz. By adjusting the values of the first capacitor C1, the second capacitor C2, and the first resistor R11, the bandwidth range of the output of the operational amplifier U1 can be adjusted, and further the output bandwidth range of the operational amplifier U1 is limited within 3.7Hz to 33.88KHZ, so that the analog signal processing circuit 160 can both satisfy the input of the audio signal and block the input of other frequency signals.

[0085] In the embodiment of the present application, the analog signal processing circuit 160 includes a second resistor R12, a third resistor R13, a fourth resistor R14, a fifth resistor R15, a sixth resistor R16, and a seventh resistor R17;

[0086] One end of the second resistor R12 is used to connect to the control power supply, the other end of the second resistor R12 is grounded through the third resistor R13, one end of the fifth resistor R15 is used to connect to the audio input device 200, the other end of the fifth resistor R15 is connected to the node between the second resistor R12 and the third resistor R13 through the fourth resistor R14, and the first input terminal of the operational amplifier U1 is connected to the node between the fourth resistor R14 and the fifth resistor R15;

[0087] One end of the sixth resistor R16 is used to connect to the audio input device 200, the other end of the sixth resistor R16 is connected to the output terminal of the operational amplifier U1 through the seventh resistor R17, and the second input terminal of the operational amplifier U1 is connected to the node between the sixth resistor R16 and the seventh resistor R17.

[0088] For ease of understanding, in the embodiment of the present application, the first input terminal of the operational amplifier U1 is the non-inverting input terminal, and the second input terminal is the inverting input terminal. For ease of understanding, a total of 6 nodes T1, T2, T3, T4, T5, and T6 are shown in the figure. According to the virtual open of the analog signal processing circuit 160, it is obtained that:

[0089]

[0090] Among them, V T1 is the voltage of the T1 node, V T2 is the voltage of the T2 node, V T3The voltage of node T3, V T4 The voltage of node T4, V T5 The voltage of node T5, V T6 The voltage of node T6, the resistance value of the fourth resistor R14 is R4, the resistance value of the fifth resistor R15 is R5, the resistance value of the sixth resistor R16 is R6, and the resistance value of the seventh resistor R17 is R7.

[0091] According to the virtual open of the analog signal processing circuit 160, we get:

[0092] V T3 = V T5 Formula (3)

[0093] Among them, V T3 The voltage of node T3, V T5 The voltage of node T5.

[0094] The analog signal processing circuit 160 also satisfies the following relationship:

[0095] R4 = R7 Formula (4)

[0096] R5 = R6 Formula (5)

[0097]

[0098] Among them, V T1 The voltage of node T1, the resistance value of the second resistor R12 is R2, the resistance value of the third resistor R13 is R3, the resistance value of the fourth resistor R14 is R4, the resistance value of the fifth resistor R15 is R5, the resistance value of the sixth resistor R16 is R6, and the resistance value of the seventh resistor R17 is R7.

[0099] According to the above formula, the output of the operational amplifier U1, that is, the voltage of node T4, is:

[0100]

[0101] Among them, V T2 The voltage of node T2, V T4 The voltage of node T4, V T6 The voltage of node T6, the resistance value of the second resistor R12 is R2, the resistance value of the third resistor R13 is R3, the resistance value of the sixth resistor R16 is R6, and the resistance value of the seventh resistor R17 is R7.

[0102] From the relational expression of the output of the operational amplifier U1, it can be determined that by adjusting the resistance values of the second resistor R12, the third resistor R13, the sixth resistor R16, and the seventh resistor R17, the output of the operational amplifier U1 can be adjusted.

[0103] In an embodiment of the present application, the audio link 100 further includes a microcontroller 190;

[0104] The distortion detection circuit 140 is connected to the system chip 150 through the microcontroller 190;

[0105] The microcontroller 190 is configured to output an interaction signal to the system chip 150 when the distortion detection circuit 140 generates a detection signal;

[0106] The system chip 150 is configured to output a control signal to the digital signal processor 120 according to the received interaction signal.

[0107] In this embodiment, the distortion detection circuit 140 determines whether the signal is distorted according to the THD (Total Harmonic Distortion) + N (Noise) signal in the power amplifier circuit 130. Specifically, it detects whether the value of the THD + N signal exceeds the calibrated signal threshold. When the value of the THD + N signal exceeds the calibrated signal threshold, the distortion detection circuit 140 generates a detection signal, thereby triggering the microcontroller 190 (Microcontroller Unit, MCU) to generate an interaction signal.

[0108] The microcontroller 190 interacts with the system chip 150, outputs the interaction signal to the system chip 150, and triggers a distortion event of the system chip 150. After the system chip 150 triggers the distortion event, it interacts with the digital signal processor 120, and outputs a control signal to the digital signal processor 120 according to the received interaction signal. The gain of the audio signal is reduced by the digital signal processor 120, thereby optimizing the signal distortion occurring in the power amplifier circuit 130. The gain adjustment method of the audio signal is set according to actual requirements and is not limited herein. For ease of understanding, in the embodiment of the present application, the gain of the audio signal is stepwise reduced by the digital signal processor 120, and the gain of the audio signal is discretely reduced in stages to avoid oscillation or instability caused by changes in the gain of the audio signal.

[0109] Please refer to Figure 4 , Figure 4 which shows a schematic structural diagram of the distortion detection circuit provided by the embodiment of the present application.

[0110] In an embodiment of the present application, the power amplifier circuit 130 includes a first power amplifier chip AMP1 and a second power amplifier chip AMP2, and the distortion detection circuit 140 includes a first voltage comparator U2 and a second voltage comparator U3;

[0111] The clip pin of the first power amplifier chip AMP1 is connected to the first input terminal of the first voltage comparator U2, and the output terminal of the first voltage comparator U2 is connected to the first input terminal of the microcontroller 190;

[0112] The clip pin of the second power amplifier chip AMP2 is connected to the first input terminal of the second voltage comparator U3, and the output terminal of the second voltage comparator U3 is connected to the second input terminal of the microcontroller 190;

[0113] The second input terminals of the first voltage comparator U2 and the second voltage comparator U3 are both connected to the signal output terminal of the microcontroller 190;

[0114] The microcontroller 190 is further configured to output the reference audio signal to the first voltage comparator U2 and the second voltage comparator U3 respectively.

[0115] Generally, a plurality of speakers need to be set in the vehicle audio device 1000. In this embodiment, according to the audio requirements of the vehicle audio device 1000, the power amplifier circuit 130 includes a first power amplifier chip AMP1 and a second power amplifier chip AMP2. The distortion detection circuit 140 corresponds to two power amplifier chips and provides the first voltage comparator U2 and the second voltage comparator U3. In this embodiment, the clip (Current Limit) pins of the first power amplifier chip AMP1 and the second power amplifier chip AMP2 are modified to a non-latching model, that is, after the pin state is triggered, the level state of the pin will not be continuously latched.

[0116] The number of consecutive PWM pulses with a duty cycle of 100% can indirectly reflect the distortion of the audio. Taking the first power amplifier chip AMP1 as an example, when the first power amplifier chip AMP1 detects that the PWM (Pulse Width Modulation) waveform output by the power amplifier circuit 130 has consecutive M pulses with a 100% duty cycle, the clip pin will be pulled low. It should be understood that M can be set through the register of the power amplifier chip, and the value of M is set according to actual needs and is not limited here. When audio distortion occurs, the level of the clip pin will continuously change between high and low.

[0117] In the embodiment of the present application, the distortion detection circuit 140 further includes a first voltage-dividing resistor R21, a second voltage-dividing resistor R22, a third voltage-dividing resistor R23, a fourth voltage-dividing resistor R24, a fifth voltage-dividing resistor R25, a sixth voltage-dividing resistor R26, a third capacitor C3 connected in parallel with the first voltage-dividing resistor R21, a fourth capacitor C4 connected in parallel with the fourth voltage-dividing resistor R24, and a fifth capacitor C5 connected in parallel with the sixth voltage-dividing resistor R26;

[0118] One end of the first voltage-dividing resistor R21 is used to connect to the control power supply. The other end of the first voltage-dividing resistor R21 is connected to the clip pin of the first power amplifier chip AMP1 through the second voltage-dividing resistor R22. The first input terminal of the first voltage comparator U2 is connected to the node between the first voltage-dividing resistor R21 and the second voltage-dividing resistor R22;

[0119] The signal output terminal of the microcontroller 190 is grounded through the third voltage-dividing resistor R23 and the fourth voltage-dividing resistor R24 in sequence;

[0120] One end of the sixth voltage-dividing resistor R26 is used to connect to the control power supply. The other end of the sixth voltage-dividing resistor R26 is connected to the clip pin of the second power amplifier chip AMP2 through the fifth voltage-dividing resistor R25. The first input terminal of the second voltage comparator U3 is connected to the node between the fifth voltage-dividing resistor R25 and the sixth voltage-dividing resistor R26.

[0121] The first voltage-dividing resistor R21 and the second voltage-dividing resistor R22 form a voltage-dividing circuit 112-AUX corresponding to the first power amplifier chip AMP1. The third voltage-dividing resistor R23 and the fourth voltage-dividing resistor R24 form a voltage-dividing circuit 112-AUX corresponding to the microcontroller 190. The fifth voltage-dividing resistor R25 and the sixth voltage-dividing resistor R26 form a voltage-dividing circuit 112-AUX corresponding to the second power amplifier chip AMP2. The third capacitor C3, the fourth capacitor C4, and the fifth capacitor C5 are all filter capacitors, which are used for signal filtering to make the output of the circuit 112-AUX a stable level.

[0122] For ease of understanding, in the embodiments of the present application, the first input terminal of the first voltage comparator U2 is the non-inverting input terminal, and the second input terminal is the inverting input terminal. Similarly, the first input terminal of the second voltage comparator U3 is the non-inverting input terminal, and the second input terminal is the inverting input terminal. Taking the first power amplifier chip AMP1 and the first voltage comparator U2 as an example, the circuit 112-AUX composed of the first voltage-dividing resistor R21, the second voltage-dividing resistor R22, and the third capacitor C3 outputs a stable level, which serves as the potential of the non-inverting input terminal of the first voltage comparator U2. The duty-cycle adjustable PWM signal output by the microcontroller 190 is sent to the circuit 112-AUX composed of the three voltage-dividing resistors, the fourth voltage-dividing resistor R24, and the fourth capacitor C4 to output a reference level to the inverting input terminal of the first voltage comparator U2.

[0123] In the embodiments of the present application, the distortion detection circuit 140 further includes a first pull-up resistor R27 and a second pull-up resistor R28;

[0124] One end of the first pull-up resistor R27 is connected to the output terminal of the first voltage comparator U2. The other end of the first pull-up resistor R27 is connected to the output terminal of the second voltage comparator U3 through the second pull-up resistor R28. The other end of the first pull-up resistor R27 is used to connect to the control power supply.

[0125] The voltage of the control power supply is set according to actual requirements and is not limited herein. For ease of understanding, in the embodiments of the present application, the voltage of the control power supply is 3.3V. Taking the first power amplifier chip AMP1 as an example, when the power amplifier circuit 130 does not show distortion, the clip pin is at a high level, and the non-inverting input terminal of the first voltage comparator U2 is also at a high level of 3.3V. The level of the inverting input terminal of the first voltage comparator U2 is less than the level of the non-inverting input terminal, causing the first voltage comparator U2 to output a high level. Since the operational amplifier U1 has an open-drain output, the first pull-up resistor R27 and the second pull-up resistor R28 are pulled up to the voltage of 3.3V.

[0126] When the power amplifier circuit 130 shows distortion, the level of the inverting input terminal of the first voltage comparator U2 is greater than the level of the non-inverting input terminal, causing the first voltage comparator U2 to output a low level. The microcontroller 190 triggers a distortion event based on the recognized low level, and then controls the digital signal processor 120 to reduce the signal gain through the system chip 150.

[0127] The present application provides an audio link 100, including: a tuning circuit 110, a digital signal processor 120, a power amplifier circuit 130, a distortion detection circuit 140, and a system chip 150; the digital signal processor 120 is sequentially connected to the input terminal of the system chip 150 through the power amplifier circuit 130 and the distortion detection circuit 140, the output terminal of the system chip 150 is connected to the control terminal of the digital signal processor 120, and the tuning circuit 110 is connected to the input terminal of the digital signal processor 120. The audio link 100 can detect and adjust the gain in a timely manner when the audio signal is distorted, so as to ensure the quality of the audio output. In addition, the audio link 100 also has a tuning function, and can adjust the audio signal through the tuning circuit 110 and the digital signal processor 120. In the case where the in-vehicle audio device 1000 does not integrate an audio processing chip, by connecting the audio link 100, it is possible to achieve multiple functions of efficient audio signal processing, distortion detection, and tuning at a low cost, and avoid the limitation of the audio function of the in-vehicle audio device 1000.

[0128] In this embodiment, a calibration method for the distortion detection circuit 140 is further provided, including:

[0129] Set the trigger conditions for the clip pins of the first power amplifier chip AMP1 and the second power amplifier chip AMP2. Adjust the audio signal to distort the signal of the power amplifier circuit 130. Obtain the input voltages of the non-inverting input terminals of the first voltage comparator U2 and the second voltage comparator U3, and obtain the output frequencies of the clip pins of the first power amplifier chip AMP1 and the second power amplifier chip AMP2. Determine the resistance values of the first voltage-dividing resistor R21, the second voltage-dividing resistor R22, the fifth voltage-dividing resistor R25, and the sixth voltage-dividing resistor R26, and determine the values of the third capacitor C3 and the fifth capacitor C5 according to the input voltages of the non-inverting input terminals of the first voltage comparator U2 and the second voltage comparator U3. Determine the input voltages of the inverting input terminals of the first voltage comparator U2 and the second voltage comparator U3 according to the input voltages of the non-inverting input terminals of the first voltage comparator U2 and the second voltage comparator U3, and the output frequencies of the clip pins of the first power amplifier chip AMP1 and the second power amplifier chip AMP2. Determine the resistance values of the third voltage-dividing resistor R23 and the fourth voltage-dividing resistor R24 required for the input voltages of the inverting input terminals, determine the duty cycle of the PWM pulse issued by the microcontroller 190, and determine the value of the fourth capacitor C4.

[0130] In this embodiment, the trigger condition for the clip pin is that the power amplifier chip detects that the output PWM signal has M consecutive pulses with a 100% duty cycle, pulling down the level of the clip pin. The distortion detection circuit 140 determines whether the signal is distorted according to the THD+N signal in the power amplifier circuit 130. Determine the resistance and capacitance values of the non-inverting input terminal according to the input voltage of the non-inverting input terminal, so that the voltage of the non-inverting input terminal meets the design requirements, and meets the requirement that the clip pin frequency is greater than the cut-off frequency of the filter circuit 112-AUX composed of the resistor and the capacitor. Determine the duty cycle of the PWM pulse according to the input voltage of the non-inverting input terminal, and it is required that the PWM pulse frequency is much greater than the cut-off frequency of the filter circuit 112-AUX composed of the resistor and the capacitor.

[0131] Please refer to Figure 5 , Figure 5 which shows the schematic structural diagram of the in-vehicle audio device provided by the embodiment of the present application.

[0132] The embodiment of the present application further provides an in-vehicle audio device 1000, and the in-vehicle audio device 1000 includes an audio input device 200, an audio output device 300, and the above-mentioned audio link 100;

[0133] The audio input device 200 is connected to the audio output device 300 through the audio link 100.

[0134] The audio input device 200 is connected to the audio output device 300 through the audio link 100. Specifically, the audio input device 200 is connected to the analog signal processing circuit 160 through the first analog switch 170 to convert the analog audio signal into a digital audio signal through the analog signal processing circuit 160. The audio output device 300 is connected to the power amplifier circuit 130 to convert the power amplifier signal into a sound signal.

[0135] It should be understood that the types of the audio input device 200 and the audio output device 300 are both set according to actual requirements and are not limited herein. For ease of understanding, in the embodiments of the present application, the audio input device 200 is an analog microphone, and the audio output device 300 is a speaker.

[0136] It should also be noted that the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent in such process, method, commodity or device. Without further limitation, the element defined by the statement "including one..." does not exclude the existence of additional identical elements in the process, method, commodity or device including the element.

[0137] The above are only the embodiments of the present application and are not used to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the scope of the claims of the present application.

Claims

1. An audio link, characterized in that, The audio link includes a tuning circuit, a digital signal processor, a power amplifier circuit, a distortion detection circuit, and a system chip; The digital signal processor is sequentially connected to the input end of the system chip through the power amplifier circuit and the distortion detection circuit. The output end of the system chip is connected to the control end of the digital signal processor, and the tuning circuit is connected to the input end of the digital signal processor; The tuning circuit is configured to input a tuning signal to the digital signal processor when the audio link is in the tuning mode; The power amplifier circuit is configured to convert the digital audio signal output by the digital signal processor into a power amplifier signal to be output; The distortion detection circuit is configured to generate a detection signal when the signal of the power amplifier circuit is distorted; The system chip is configured to output a control signal to the digital signal processor when the distortion detection circuit generates a detection signal; The digital signal processor is configured to adjust the gain of the digital audio signal according to the received control signal.

2. The audio link according to claim 1, characterized in that, The audio link includes an analog signal processing circuit; The output end of the analog signal processing circuit is connected to the input end of the digital signal processor; The analog signal processing circuit is configured to convert the received analog audio signal into a digital audio signal and output the digital audio signal to the digital signal processor.

3. The audio link according to claim 2, characterized in that, The audio link further includes a first analog switch and a second analog switch; The first analog switch is connected to the digital signal processor through the analog signal processing circuit. The system chip is connected to the digital signal processor through the second analog switch, and the tuning circuit is connected to the node between the first analog switch and the analog signal processing circuit; The first analog switch and the second analog switch are configured to remain disconnected when the audio link is in the tuning mode.

4. The audio link according to claim 2, wherein The analog signal processing circuit includes at least two audio signal processing sub-circuits, and each audio signal processing sub-circuit includes an operational amplifier, a low-pass filter, and a high-pass filter; The low-pass filter includes a first capacitor and a first resistor, and the high-pass filter includes a second capacitor and an analog-to-digital converter; The output end of the operational amplifier is grounded sequentially through the first capacitor and the first resistor, and the first capacitor and the first resistor are also connected to the analog-to-digital converter through the second capacitor; The first input end and the second input end of the operational amplifier are both configured to be connected to an audio input device.

5. The audio link according to claim 4, characterized in that, The analog signal processing circuit includes a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, and a seventh resistor; One end of the second resistor is configured to be connected to a control power supply, the other end of the second resistor is grounded through the third resistor, one end of the fifth resistor is configured to be connected to the audio input device, the other end of the fifth resistor is connected to the node between the second resistor and the third resistor through the fourth resistor, and the first input end of the operational amplifier is connected to the node between the fourth resistor and the fifth resistor; One end of the sixth resistor is used to connect to the audio input device, and the other end of the sixth resistor is connected to the output end of the operational amplifier through the seventh resistor. The second input end of the operational amplifier is connected to the node between the sixth resistor and the seventh resistor.

6. The audio link according to claim 1, characterized in that, The audio link further includes a microcontroller; The distortion detection circuit is connected to the system chip through the microcontroller; The microcontroller is configured to output an interaction signal to the system chip when the distortion detection circuit generates a detection signal; The system chip is configured to output a control signal to the digital signal processor according to the received interaction signal.

7. The audio link according to claim 6, wherein The power amplifier circuit includes a first power amplifier chip and a second power amplifier chip, and the distortion detection circuit includes a first voltage comparator and a second voltage comparator; The clip pin of the first power amplifier chip is connected to the first input end of the first voltage comparator, and the output end of the first voltage comparator is connected to the first input end of the microcontroller; The clip pin of the second power amplifier chip is connected to the first input end of the second voltage comparator, and the output end of the second voltage comparator is connected to the second input end of the microcontroller; The second input ends of the first voltage comparator and the second voltage comparator are both connected to the signal output end of the microcontroller; The microcontroller is further configured to output a reference audio signal to the first voltage comparator and the second voltage comparator respectively.

8. The audio link according to claim 7, wherein The distortion detection circuit further includes a first voltage-dividing resistor, a second voltage-dividing resistor, a third voltage-dividing resistor, a fourth voltage-dividing resistor, a fifth voltage-dividing resistor, a sixth voltage-dividing resistor, a third capacitor connected in parallel with the first voltage-dividing resistor, a fourth capacitor connected in parallel with the fourth voltage-dividing resistor, and a fifth capacitor connected in parallel with the sixth voltage-dividing resistor; One end of the first voltage-dividing resistor is used to connect to a control power supply, and the other end of the first voltage-dividing resistor is connected to the clip pin of the first power amplifier chip through the second voltage-dividing resistor. The first input end of the first voltage comparator is connected to the node between the first voltage-dividing resistor and the second voltage-dividing resistor; The signal output end of the microcontroller is grounded sequentially through the third voltage-dividing resistor and the fourth voltage-dividing resistor; One end of the sixth voltage-dividing resistor is used to connect to a control power supply, and the other end of the sixth voltage-dividing resistor is connected to the clip pin of the second power amplifier chip through the fifth voltage-dividing resistor. The first input end of the second voltage comparator is connected to the node between the fifth voltage-dividing resistor and the sixth voltage-dividing resistor.

9. The audio link according to claim 7, characterized in that, The distortion detection circuit further includes a first pull-up resistor and a second pull-up resistor; One end of the first pull-up resistor is connected to the output end of the first voltage comparator, and the other end of the first pull-up resistor is connected to the output end of the second voltage comparator through the second pull-up resistor. The other end of the first pull-up resistor is used to connect to a control power supply.

10. An in-vehicle audio device, characterized in that, The in-vehicle audio device includes an audio input device, an audio output device, and the audio link according to any one of claims 1 to 9; The audio input device is connected to the audio output device through the audio link.

Images