Differential vehicle-mounted microphone module

Abstract

The utility model relates to differential formula vehicle -mounted microphone module, including microphone module MIC1, is used for gathering audio signal, input signal conditioning module is connected with the signal output end of microphone module MIC1, is used for carrying out conditioning to microphone signal, gain module its input end is connected with the output of input signal conditioning module, difference output module is connected with the output of gain module, is used for converting the single -end signal after gain adjustment into difference signal, difference output module is connected with the output of gain module, is used for converting the single -end signal after gain adjustment into difference signal, difference output module includes double operational amplifier U1, feedback module and output protection module, connector is used for the signal output after difference output module processing is exported to external device, the utility model discloses utilize difference signal output, effectively offsets common mode noise, improves microphone module in complex electromagnetic environment such as vehicle -mounted anti -interference ability, ensures the intelligibility and reliability of audio signal.

Description

Technical Field

[0001] This utility model relates to the field of audio signal processing technology, and in particular to a differential vehicle microphone module. Background Technology

[0002] With the rapid development and widespread application of electronic devices, microphones, as a key component for audio signal acquisition, are playing an increasingly important role in the fields of computers, mobile phones, automobiles, smart homes, and artificial intelligence. These applications place higher demands on the performance of microphones, especially in the in-vehicle environment, where microphones need to work stably in complex electromagnetic environments while resisting interference from wireless communications (such as WiFi).

[0003] Traditional microphone modules, especially MEMS microphones with metal housings, have a certain degree of anti-interference capability. However, with the development of wireless communication technology and the increase in electromagnetic interference sources, the design of automotive microphone modules needs to consider not only anti-interference capability but also signal integrity and electromagnetic compatibility. Traditional analog microphone modules may not be able to meet these requirements, especially in complex electromagnetic environments.

[0004] Therefore, there is an urgent need for a differential vehicle microphone module to address the shortcomings of existing technologies. Utility Model Content

[0005] Therefore, the technical problem to be solved by this utility model is to overcome the shortcomings of the prior art and provide a differential vehicle microphone module that uses differential signal output to effectively cancel common-mode noise, significantly improves the anti-interference ability of the microphone module in complex electromagnetic environments such as vehicles, and ensures the clarity and reliability of audio signals.

[0006] To solve the above-mentioned technical problems, this utility model provides a differential vehicle microphone module, comprising: The microphone module MIC1 is used to collect audio signals; An input signal conditioning module is connected to the signal output terminal of the microphone module MIC1 and is used to condition the microphone signal. A gain module, whose input terminal is connected to the output terminal of the input signal conditioning module, is used to adjust the gain of the signal conditioned by the input signal conditioning module. A differential output module, connected to the output of the gain module, is used to convert the gain-adjusted single-ended signal into a differential signal. The differential output module includes a dual operational amplifier U1, a feedback module, and an output protection module. The feedback module is connected to the dual operational amplifier U1 for impedance matching, gain setting, and AC coupling. The power input of the dual operational amplifier U1 is connected to the power supply VCC via a ferrite bead. The output protection module is connected to the first output terminal OUT1 and the second output terminal OUT2 of the dual operational amplifier U1, and is used to provide current limiting protection for the output of the dual operational amplifier U1. A connector is used to output the signal processed by the differential output module to an external device.

[0007] In one embodiment of this utility model, a power filtering module is further included, which is connected to the power input terminal of the microphone module MIC1, and is used to filter out high-frequency noise on the power line; the power filtering module includes a first inductor L1, a seventh capacitor C7 and a fifth electrostatic discharge protection element ESD5, the electrostatic discharge protection element ESD5 and the seventh capacitor C7 are connected in parallel, and the first terminals of the seventh capacitor C7 and the electrostatic discharge protection element ESD5 are both connected to the ground terminal, and the second terminal of the first inductor L1 is connected to the power input terminal of the microphone.

[0008] In one embodiment of this utility model, the input signal conditioning module includes a first resistor R1, a second resistor R2, a third resistor R3, and a first capacitor C1. The first resistor R1 and the second resistor R2 are connected in series. The first end of the first capacitor C1 is connected to the first end of the second resistor R2. The second end of the first capacitor C1 is connected to the intermediate connection point of the first resistor R1 and the second resistor R2 and the first end of the third resistor R3.

[0009] In one embodiment of this utility model, the gain module includes a second capacitor C2, a first adjustable resistor RA1, a second adjustable resistor RA2, an eighth capacitor C8, a fourth resistor R4, and a fifth resistor R5. The first end of the second capacitor C2 is connected to the signal output terminal of the microphone module MIC1, and the second end of the second capacitor C2 is connected to the first end of the second adjustable resistor RA2. The second end of the second adjustable resistor RA2 is connected to the first end of the first adjustable resistor RA1 and the first inverting input terminal IN- of the dual operational amplifier U1. The second end of the first adjustable resistor RA1 is connected to the first output terminal OUT1 of the dual operational amplifier U1. The eighth capacitor C8 is connected in parallel with the second adjustable resistor RA2. The first end of the fourth resistor R4 is connected to the second end of the second resistor R2, and the second end of the fourth resistor R4 is connected to the first non-inverting input terminal IN+ of the dual operational amplifier U1. The first end of the fifth resistor R5 is connected to the first non-inverting input terminal IN+ of the dual operational amplifier U1, and the second end of the fifth resistor R5 is connected to the ground terminal.

[0010] In one embodiment of this utility model, the gain module further includes a third capacitor C3 and a tenth capacitor C10, both of which are connected in parallel with the fifth resistor R5.

[0011] In one embodiment of this utility model, the feedback module includes a first feedback resistor RB1, a second feedback resistor RB2, and a ninth capacitor C9. The first feedback resistor RB1 is connected between the second output terminal OUT2 and the second inverting input terminal IN2- of the dual operational amplifier U1. The second feedback resistor RB2 is disposed between the first output terminal OUT1 and the second inverting input terminal IN2-. The ninth capacitor C9 is connected in parallel with the first feedback resistor RB1.

[0012] In one embodiment of this utility model, the output protection module includes a seventh resistor R7, an eighth resistor R8, a second electrostatic discharge protection element ESD2, and a third electrostatic discharge protection element ESD3. The seventh resistor R7 is disposed between the second output terminal of the dual operational amplifier U1 and the MIC+ terminal of the connector; the eighth resistor R8 is disposed between the first output terminal of the dual operational amplifier U1 and the MIC- terminal of the connector. The second terminal of the seventh resistor R7 is connected to the ground terminal through the second electrostatic discharge protection element ESD2, and the eighth resistor R8 is connected to the ground terminal through the third electrostatic discharge protection element ESD3.

[0013] In one embodiment of this utility model, a power decoupling module is further included. The power decoupling module is disposed between the power input terminal and the ground terminal of the dual operational amplifier U1 and is used to decouple the power supplied to the dual operational amplifier U1. The power decoupling module includes a fourth capacitor C4, a fifth capacitor C5 and a fourth electrostatic discharge protection element ESD4. The fourth capacitor C4, the fifth capacitor C5 and the fourth electrostatic discharge protection element ESD4 are connected in parallel between the power pin and the ground terminal of the dual operational amplifier U1.

[0014] In one embodiment of this utility model, a sixth resistor R6 is further included. The first end of the sixth resistor R6 is connected to the ground terminal, and the second end of the sixth resistor R6 is connected to the SHD pin of the connector.

[0015] In one embodiment of this utility model, the output terminal of the microphone module MIC1 is connected to the sixth capacitor C6 and the first electrostatic discharge protection element ESD1.

[0016] Compared with the prior art, the above-mentioned technical solution of this utility model has the following beneficial effects: The differential vehicle microphone module described in this utility model combines an input signal conditioning module and a gain module to ensure the integrity of the audio signal during amplification, reduce signal distortion, and improve sound quality. By using a differential output module to convert the amplified single-ended signal into a differential signal output, common-mode noise can be effectively canceled, significantly improving the signal's anti-interference capability, thereby maintaining the clarity and reliability of the audio signal in the high electromagnetic interference environment of a vehicle. Attached Figure Description

[0017] To make the content of this utility model easier to understand, the present utility model will be further described in detail below with reference to specific embodiments and accompanying drawings. Figure 1 This is a circuit diagram of the differential vehicle microphone module in a preferred embodiment of the present invention; Figure 2 This is a schematic diagram of the structure and circuit of the dual operational amplifier U1 of this utility model. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments are not intended to limit the present invention.

[0019] Reference Figure 1 As shown, this utility model provides a differential vehicle microphone module, comprising: The microphone module MIC1 is used to collect audio signals; The input signal conditioning module is connected to the signal output terminal of the microphone module MIC1 and is used to condition the microphone signal. The gain module, whose input is connected to the output of the input signal conditioning module, is used to adjust the gain of the signal after it has been conditioned by the input signal conditioning module. The differential output module, connected to the output of the gain module, is used to convert the gain-adjusted single-ended signal into a differential signal. The differential output module includes a dual operational amplifier U1, a feedback module, and an output protection module. The feedback module is connected to the dual operational amplifier U1 for impedance matching, gain setting, and AC coupling. The power input of the dual operational amplifier U1 is connected to the power supply VCC via a ferrite bead. The output protection module is connected to the first output terminal OUT1 and the second output terminal OUT2 of the dual operational amplifier U1, and is used to provide current limiting protection for the output of the dual operational amplifier U1. Connectors are used to output signals processed by the differential output module to external devices.

[0020] In this embodiment, the dual operational amplifier U1 is preferably the OPA1652, which features low noise, low quiescent current, low distortion, general-purpose FET input audio operational amplifier, and is unity-gain stable, providing excellent dynamic performance over a wide load range.

[0021] It also includes a power filtering module, connected to the power input terminal of the microphone module MIC1, used to filter out high-frequency noise on the power line. The power filtering module includes a first inductor L1, a seventh capacitor C7, and a fifth electrostatic discharge (ESD) protection element ESD5. The ESD protection element ESD5 and the seventh capacitor C7 are connected in parallel, and the first terminals of both the seventh capacitor C7 and the ESD protection element ESD5 are connected to the ground terminal. The second terminal of the first inductor L1 is connected to the power input terminal of the microphone. The design of the power filtering module effectively filters out high-frequency noise on the power line, providing a more stable power supply for the microphone module MIC1. The parallel connection of the fifth ESD protection element ESD5 and the seventh capacitor C7 enhances the protection capability of the power supply and improves the safety of the circuit.

[0022] The input signal conditioning module includes a first resistor R1, a second resistor R2, a third resistor R3, and a first capacitor C1. The first resistor R1 and the second resistor R2 are connected in series. The first terminal of the first capacitor C1 is connected to the first terminal of the second resistor R2, and the second terminal of the first capacitor C1 is connected to the midpoint between the first and second resistors R1 and R2, and the first terminal of the third resistor R3. The input signal conditioning module sets appropriate input impedances for the second resistor R2 and the third resistor R3 to match the output impedance of the microphone module MIC1 and the input impedance of the operational amplifier, thereby maximizing signal transmission efficiency and reducing signal reflection. The first capacitor C1, together with the first resistor R1 and the second resistor R2, forms an RC filter to achieve low-pass filtering, allowing low-frequency signals to pass while attenuating high-frequency signals.

[0023] The gain module includes a second capacitor C2, a first adjustable resistor RA1, a second adjustable resistor RA2, an eighth capacitor C8, a fourth resistor R4, and a fifth resistor R5. The first end of the second capacitor C2 is connected to the signal output terminal of the microphone module MIC1. The second end of the second capacitor C2 is connected to the first end of the second adjustable resistor RA2. The second end of the second adjustable resistor RA2 is connected to the first end of the first adjustable resistor RA1 and the first inverting input terminal IN- of the dual operational amplifier U1. The second end of the first adjustable resistor RA1 is connected to the first output terminal OUT1 of the dual operational amplifier U1. The eighth capacitor C8 is connected in parallel with the second adjustable resistor RA2. The first end of the fourth resistor R4 is connected to the second end of the second resistor R2. The second end of the fourth resistor R4 is connected to the first non-inverting input terminal IN+ of the dual operational amplifier U1. The first end of the fifth resistor R5 is connected to the first non-inverting input terminal IN+ of the dual operational amplifier U1. The second end of the fifth resistor R5 is connected to the ground terminal.

[0024] The gain module also includes a third capacitor C3 and a tenth capacitor C10, both of which are connected in parallel with the fifth resistor R5.

[0025] In one embodiment of this invention, the feedback module includes a first feedback resistor RB1, a second feedback resistor RB2, and a ninth capacitor C9. The first feedback resistor RB1 is connected between the second output terminal OUT2 and the second inverting input terminal IN2- of the dual operational amplifier U1. The second feedback resistor RB2 is located between the first output terminal OUT1 and the second inverting input terminal IN2-. The ninth capacitor C9 is connected in parallel with the first feedback resistor RB1. The feedback module optimizes the feedback control of the dual operational amplifier U1, improving gain stability and frequency response.

[0026] In one embodiment of this invention, the output protection module includes a seventh resistor R7, an eighth resistor R8, a second electrostatic discharge (ESD) protection element ESD2, and a third ESD protection element ESD3. The seventh resistor R7 is positioned between the second output terminal of the dual operational amplifier U1 and the MIC+ terminal of the connector; the eighth resistor R8 is positioned between the first output terminal of the dual operational amplifier U1 and the MIC- terminal of the connector. The second terminal of the seventh resistor R7 is connected to the ground terminal via the second ESD protection element ESD2, and the eighth resistor R8 is connected to the ground terminal via the third ESD protection element ESD3. The seventh resistor R7 and the eighth resistor R8 provide current-limiting protection for the output of the dual operational amplifier U1, enhancing the circuit's durability and safety.

[0027] It also includes a power supply decoupling module, which is located at the power input and ground terminals of the dual operational amplifier U1 to decouple the power supplied to the dual operational amplifier U1. The power supply decoupling module includes a fourth capacitor C4, a fifth capacitor C5, and a fourth electrostatic discharge protection element ESD4, which are connected in parallel between the power supply pin and the ground terminal of the dual operational amplifier U1. The power supply decoupling module provides a more stable power supply for the dual operational amplifier U1 and reduces the impact of power supply noise on the circuit.

[0028] The power decoupling module also includes a sixth resistor, R6. The first terminal of R6 is connected to the ground terminal, and the second terminal is connected to the SHD pin of the connector. The integration of the sixth resistor R6 provides a more stable ground connection, reduces ground noise, and improves the overall performance of the circuit. The output of microphone module MIC1 is connected to the sixth capacitor C6 and the first electrostatic discharge protection element ESD1. This design provides additional ESD protection and signal coupling for the output of microphone module MIC1, improving its reliability.

[0029] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the protection scope of this invention.

Claims

1. A differential vehicle-mounted microphone module, characterized in that: include: The microphone module MIC1 is used to collect audio signals; An input signal conditioning module is connected to the signal output terminal of the microphone module MIC1 and is used to condition the microphone signal. A gain module, whose input terminal is connected to the output terminal of the input signal conditioning module, is used to adjust the gain of the signal conditioned by the input signal conditioning module. A differential output module, connected to the output of the gain module, is used to convert the gain-adjusted single-ended signal into a differential signal. The differential output module includes a dual operational amplifier U1, a feedback module, and an output protection module. The feedback module is connected to the dual operational amplifier U1 for impedance matching, gain setting, and AC coupling. The power input of the dual operational amplifier U1 is connected to the power supply VCC via a ferrite bead. The output protection module is connected to the first output terminal OUT1 and the second output terminal OUT2 of the dual operational amplifier U1, and is used to provide current limiting protection for the output of the dual operational amplifier U1. A connector is used to output the signal processed by the differential output module to an external device.

2. The differential vehicle-mounted microphone module according to claim 1, characterized in that: It also includes a power filtering module, which is connected to the power input terminal of the microphone module MIC1, and is used to filter out high-frequency noise on the power line. The power filtering module includes a first inductor L1, a seventh capacitor C7 and a fifth electrostatic discharge protection element ESD5. The electrostatic discharge protection element ESD5 and the seventh capacitor C7 are connected in parallel, and the first terminals of the seventh capacitor C7 and the electrostatic discharge protection element ESD5 are both connected to the ground terminal. The second terminal of the first inductor L1 is connected to the power input terminal of the microphone.

3. A differential vehicle-mounted microphone module according to claim 1, characterized in that: The input signal conditioning module includes a first resistor R1, a second resistor R2, a third resistor R3, and a first capacitor C1. The first resistor R1 and the second resistor R2 are connected in series. The first end of the first capacitor C1 is connected to the first end of the second resistor R2. The second end of the first capacitor C1 is connected to the midpoint between the first resistor R1 and the second resistor R2 and the first end of the third resistor R3.

4. A differential vehicle-mounted microphone module according to claim 3, characterized in that: The gain module includes a second capacitor C2, a first adjustable resistor RA1, a second adjustable resistor RA2, an eighth capacitor C8, a fourth resistor R4, and a fifth resistor R5. The first end of the second capacitor C2 is connected to the signal output terminal of the microphone module MIC1, and the second end of the second capacitor C2 is connected to the first end of the second adjustable resistor RA2. The second end of the second adjustable resistor RA2 is connected to the first end of the first adjustable resistor RA1 and the first inverting input terminal IN- of the dual operational amplifier U1. The second end of the first adjustable resistor RA1 is connected to the first output terminal OUT1 of the dual operational amplifier U1. The eighth capacitor C8 is connected in parallel with the second adjustable resistor RA2. The first end of the fourth resistor R4 is connected to the second end of the second resistor R2, and the second end of the fourth resistor R4 is connected to the first non-inverting input terminal IN+ of the dual operational amplifier U1. The first end of the fifth resistor R5 is connected to the first non-inverting input terminal IN+ of the dual operational amplifier U1, and the second end of the fifth resistor R5 is connected to the ground terminal.

5. A differential vehicle-mounted microphone module according to claim 4, characterized in that: The gain module also includes a third capacitor C3 and a tenth capacitor C10, both of which are connected in parallel with the fifth resistor R5.

6. A differential vehicle-mounted microphone module according to claim 1, characterized in that: The feedback module includes a first feedback resistor RB1, a second feedback resistor RB2, and a ninth capacitor C9. The first feedback resistor RB1 is connected between the second output terminal OUT2 and the second inverting input terminal IN2- of the dual operational amplifier U1. The second feedback resistor RB2 is located between the first output terminal OUT1 and the second inverting input terminal IN2-. The ninth capacitor C9 is connected in parallel with the first feedback resistor RB1.

7. A differential vehicle-mounted microphone module according to claim 1, characterized in that: The output protection module includes a seventh resistor R7, an eighth resistor R8, a second electrostatic discharge protection element ESD2, and a third electrostatic discharge protection element ESD3. The seventh resistor R7 is disposed between the second output terminal of the dual operational amplifier U1 and the MIC+ terminal of the connector; the eighth resistor R8 is disposed between the first output terminal of the dual operational amplifier U1 and the MIC- terminal of the connector. The second terminal of the seventh resistor R7 is connected to the ground terminal through the second electrostatic discharge protection element ESD2, and the eighth resistor R8 is connected to the ground terminal through the third electrostatic discharge protection element ESD3.

8. A differential vehicle-mounted microphone module according to claim 1, characterized in that: It also includes a power decoupling module, which is disposed between the power input terminal and the ground terminal of the dual operational amplifier U1, and is used to decouple the power supplied to the dual operational amplifier U1; the power decoupling module includes a fourth capacitor C4, a fifth capacitor C5 and a fourth electrostatic discharge protection element ESD4, which are connected in parallel between the power pin and the ground terminal of the dual operational amplifier U1.

9. A differential vehicle-mounted microphone module according to claim 8, characterized in that: The power decoupling module also includes a sixth resistor R6, the first end of which is connected to the ground terminal, and the second end of which is connected to the SHD pin of the connector.

10. A differential vehicle-mounted microphone module according to claim 1, characterized in that: The output terminal of the microphone module MIC1 is connected to the sixth capacitor C6 and the first electrostatic discharge protection element ESD1.

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