Wide-amplitude audio input circuit and microphone
By designing a wide-amplitude audio input circuit and combining amplitude amplification and attenuation modules with a switching module, the problems of damage and poor processing effect of existing audio input circuits when the sound amplitude is too large or too small are solved, and the microphone achieves stable and clear sound pickup in different sound environments.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- GUANGZHOU BAOLUN ELECTRONICS CO LTD
- Filing Date
- 2025-05-26
- Publication Date
- 2026-05-01
AI Technical Summary
Existing audio input circuits are prone to burning out active components in subsequent modules when the input sound amplitude is too high, leading to microphone damage. Furthermore, when the input sound amplitude is too low, the subsequent module's processing effect on the audio signal is poor, resulting in a poor user experience.
Design a wide-amplitude audio input circuit, including an amplitude amplification module, an amplitude attenuation module, a switching module, and an amplitude sampling module. The switching module controls the amplification or attenuation of the audio signal as an equalized audio signal output by the judgment module, ensuring that the amplitude of the audio signal received by the subsequent processing module is moderate.
It effectively broadens the variable range of input sound amplitude, avoids device damage caused by excessive audio signal amplitude, improves safety and circuit lifespan, and improves the post-processing effect, ensuring the clarity of microphone sound pickup and user experience.
Smart Images
Figure CN224192028U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of circuits, and in particular to a wide-amplitude audio input circuit and microphone. Background Technology
[0002] This section is intended to provide background or context for the embodiments of the present invention set forth herein. The description herein is not intended to imply that it is prior art simply because it is included in this section.
[0003] Microphones all include an internal audio input circuit. This circuit converts sound into an audio signal, which is then transmitted to subsequent modules such as an ADC (Analog-to-Digital Converter) for post-processing. However, existing audio input circuits, when the input sound amplitude is too high, will produce a high-amplitude audio signal. This high-amplitude signal, when input to subsequent modules, may burn out the active components in the modules, potentially damaging the microphone. Conversely, when the input sound amplitude is too low, the existing audio input circuits will produce a low-amplitude audio signal. Post-processing of low-amplitude audio signals by subsequent modules is ineffective, resulting in problems such as blurry sound reception and a poor user experience. Utility Model Content
[0004] Therefore, the purpose of this utility model is to provide a wide-range audio input circuit and microphone.
[0005] This utility model provides a wide-amplitude audio input circuit, comprising: an amplitude amplification module for amplifying the original audio signal to obtain an amplified audio signal; an amplitude attenuation module for attenuating the original audio signal to obtain an attenuated audio signal; a switching module connected to the output terminals of the amplitude amplification module and the amplitude attenuation module, for outputting the amplified audio signal or the attenuated audio signal as an equalized audio signal; an amplitude sampling module for sampling the amplitude of the original audio signal to obtain a sampled amplitude; and a judgment module for controlling the switching module to output the amplified audio signal or the attenuated audio signal as an equalized audio signal based on the sampled amplitude.
[0006] This invention's wide-amplitude audio input circuit suppresses the amplitude of the original audio signal when the input sound amplitude is too high, and amplifies the amplitude of the original audio signal when the input sound amplitude is too low, ensuring that the amplitude of the equalized audio signal output to the subsequent processing module is moderate. This avoids damage to sensitive components caused by excessively large original audio signal amplitude, improving safety and extending circuit lifespan. Furthermore, it improves the post-processing effect of the audio signal, avoiding signal saturation distortion, ensuring clear microphone pickup, and providing a better user experience. Compared to existing audio input circuits, this invention significantly expands the variable range of input sound amplitude, allowing the microphone to acquire a relatively balanced audio signal whether the user shouts loudly or whispers.
[0007] Further, the switching module includes: a first switch disposed between the output terminal of the amplitude amplification module and the input terminal of the post-processing module, and a second switch disposed between the output terminal of the amplitude attenuation module and the input terminal of the post-processing module; the judgment module controls the switching module to output the amplified audio signal or the attenuated audio signal as an equalized audio signal according to the sampled amplitude, specifically including: if the sampled amplitude is greater than or equal to a preset threshold, controlling the first switch in the switching module to open and the second switch to open, thereby making the attenuated audio signal output as an equalized audio signal; if the sampled amplitude is less than the preset threshold, controlling the first switch in the switching module to open and the second switch to open, thereby making the amplified audio signal output as an equalized audio signal.
[0008] Furthermore, the judgment module is a comparator or a microcontroller; the first switch and the second switch are transistors or MOSFETs; the output terminal of the judgment module is connected to the base or gate of the first switch and the second switch.
[0009] Furthermore, the amplitude amplification module, amplitude attenuation module, and amplitude sampling module are all proportional amplifier circuits based on operational amplifiers.
[0010] Furthermore, the amplitude amplification module specifically includes: a first operational amplifier, a first resistor, a second resistor, a third resistor, and a first capacitor; the non-inverting input terminal of the first operational amplifier is connected to the original audio signal through the first resistor, and the inverting input terminal is grounded through the second resistor; the third resistor and the first capacitor are both connected across the inverting input terminal and the output terminal of the first operational amplifier; the output terminal of the first operational amplifier outputs the amplified audio signal.
[0011] Furthermore, the amplitude attenuation module specifically includes: a second operational amplifier, a fourth resistor, a fifth resistor, a third operational amplifier, a sixth resistor, a seventh resistor, and a second capacitor; the inverting input terminal of the second operational amplifier is connected to the original audio signal through the fourth resistor, and the non-inverting input terminal is grounded; the fifth resistor is connected between the inverting input terminal and the output terminal of the second operational amplifier; the inverting input terminal of the third operational amplifier is connected to the output terminal of the second operational amplifier through the sixth resistor, and the non-inverting input terminal is grounded; the seventh resistor and the second capacitor are connected between the inverting input terminal and the output terminal of the third operational amplifier; the output terminal of the third operational amplifier outputs the attenuated audio signal.
[0012] Furthermore, the amplitude sampling module specifically includes: a fourth operational amplifier, an eighth resistor, a ninth resistor, a first diode, a second diode, and a third capacitor; the inverting input terminal of the fourth operational amplifier is connected to the original audio signal through the eighth resistor, and the non-inverting input terminal is grounded; the ninth resistor is connected between the inverting input terminal and the output terminal of the fourth operational amplifier; the anode of the first diode is connected to the output terminal of the fourth operational amplifier; the anode of the second diode is connected to the non-inverting input terminal of the fourth operational amplifier, and the cathode is connected to the cathode of the first diode; one end of the third capacitor is connected to the cathode of the first diode D1, and the other end is grounded; the cathode of the first diode outputs the sampled amplitude to the judgment module.
[0013] Furthermore, the first operational amplifier and the fourth operational amplifier are integrated in the first dual operational amplifier chip; the second operational amplifier and the third operational amplifier are integrated in the second dual operational amplifier chip; and the first switch and the second switch of the switching module are integrated in the analog switch chip.
[0014] Furthermore, the first dual operational amplifier chip and the second dual operational amplifier chip are both NJM5532M; the analog switch chip is CH443K; and the judgment module is a microcontroller, model ESP32-C3.
[0015] Based on the same inventive concept, this utility model also provides a microphone, the internal circuit of which includes: any of the above-mentioned wide-amplitude audio input circuits, and a post-processing module; the audio input circuit is used to receive sound and convert the sound into a raw audio signal, and then perform gain control on the raw audio signal to obtain an equalized audio signal; the post-processing module is used to perform post-processing on the equalized audio signal.
[0016] To better understand and implement this invention, the following detailed description is provided in conjunction with the accompanying drawings. Attached Figure Description
[0017] Figure 1This is a schematic diagram of the internal circuit of the microphone of this utility model;
[0018] Figure 2 This is a schematic diagram of the wide-amplitude audio input circuit of this utility model;
[0019] Figure 3 This is a schematic diagram of the wide-amplitude audio input circuit of Embodiment 1 of this utility model;
[0020] Figure 4 This is a schematic diagram of the wide-amplitude audio input circuit of Embodiment 2 of this utility model. Detailed Implementation
[0021] It should be understood that the described embodiments are merely some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of the embodiments of this application.
[0022] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the embodiments of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.
[0023] In the following description, when referring to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims. In the description of this application, it should be understood that the terms "first," "second," "third," etc., are used only to distinguish similar objects and are not necessarily used to describe a specific order or sequence, nor should they be construed as indicating or implying relative importance. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.
[0024] Furthermore, in the description of this application, "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. The character " / " generally indicates that the related objects before and after it are in an "or" relationship.
[0025] It should be understood that the embodiments of this application are not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from their scope. The scope of the embodiments of this application is limited only by the appended claims.
[0026] This invention addresses the shortcomings of existing audio input circuits, such as excessively large or small sound amplitudes. When the input sound amplitude is too large, it suppresses the amplitude of the original audio signal; when the input sound amplitude is too small, it amplifies the amplitude of the original audio signal. This results in an audio signal with a moderate amplitude output to the subsequent processing module, thereby greatly expanding the range of possible input sound amplitude variations. It provides high safety and good sound reception in both noisy and quiet environments.
[0027] Please see Figure 1 , Figure 1 This is a schematic diagram of the internal circuitry of the microphone of this invention. The internal circuitry of the microphone of this invention includes: an audio input circuit 1 and a post-processing module 2. The audio input circuit 1 is the wide-amplitude audio input circuit of this invention, used to receive sound and convert it into a raw audio signal. Then, gain control is applied to the raw audio signal to obtain an equalized audio signal, which is then transmitted to the post-processing module 2. The post-processing module 2 is used to perform analog-to-digital conversion, noise reduction, equalization, compression, and other post-processing on the equalized audio signal to meet user needs. The post-processing module 2 may include functional modules such as an ADC (analog-to-digital converter), a filter, and a processor. Those skilled in the art can determine the specific functions and structure of the post-processing module 2 as needed; this invention does not impose specific limitations.
[0028] Please see Figure 2 , Figure 2 This is a schematic diagram of the wide-amplitude audio input circuit of this utility model. The audio input circuit 1 includes: an amplitude amplification module 11, an amplitude attenuation module 12, a switching module 13, an amplitude sampling module 14, and a judgment module 15.
[0029] The amplitude amplification module 11 amplifies the original audio signal to obtain an amplified audio signal. The amplitude attenuation module 12 attenuates the original audio signal to obtain an attenuated audio signal. The switching module 13 is connected to the output terminals of the amplitude amplification module 11 and the amplitude attenuation module 12, and is used to transmit the amplified audio signal or the attenuated audio signal as an equalized audio signal to the subsequent processing module 2.
[0030] The amplitude sampling module 14 is used to sample the amplitude of the original audio signal to obtain a sampled amplitude, and transmit the sampled amplitude to the judgment module 15. The judgment module 15 determines whether the amplitude of the original audio signal is too large based on the magnitude of the sampled amplitude, and controls the switching module 13 to transmit the amplified audio signal or the attenuated audio signal as an equalized audio signal to the post-processing module 2 based on the judgment result.
[0031] Specifically, the amplitude amplification module 11 and the amplitude attenuation module 12 are proportional amplifier circuits based on operational amplifiers. The gain of the proportional amplifier circuit can be adjusted by changing the resistance value of the resistors in the proportional amplifier circuit. When the gain is greater than 1, the amplitude amplification module 11 amplifies the original audio signal. When the gain is less than 1, the amplitude attenuation module 12 attenuates the original audio signal.
[0032] Specifically, the judgment module 15 determines whether the amplitude of the original audio signal is too large by comparing the sampled amplitude with a preset threshold. If the sampled amplitude is greater than or equal to the preset threshold, the amplitude of the original audio signal is determined to be too large. In this case, the judgment module 15 controls the switching module 13 to transmit the attenuated audio signal as an equalized audio signal to the post-processing module 2. If the sampled amplitude is less than the preset threshold, the amplitude of the original audio signal is determined not to be too large. In this case, the judgment module 15 controls the switching module 13 to transmit the amplified audio signal as an equalized audio signal to the post-processing module 2. The judgment module 15 can be a comparator circuit based on an operational amplifier or a microcontroller.
[0033] Specifically, the switching module 13 includes a first switch S1 disposed between the output terminal of the amplitude amplification module and the input terminal of the post-processing module, and a second switch S2 disposed between the output terminal of the amplitude attenuation module and the input terminal of the post-processing module. The judgment module 15 specifically controls the switching module 13 to transmit the amplified audio signal or the attenuated audio signal as an equalized audio signal to the post-processing module 2 by controlling the on / off state of the first switch S1 and the second switch S2.
[0034] In one embodiment, the first switch S1 and / or the second switch S2 are transistors and / or MOSFETs. The signal output terminal of the judgment module 15 is electrically connected to the base and / or gate of the first switch S1 and / or the second switch S2. The judgment module 15 controls the conduction or cutoff of the CBE (collector-base-emitter junction) conduction channel and / or DS (drain-source) channel of the transistor and / or MOSFET by controlling the level state of its signal output terminal, thereby controlling the on / off state of the first switch S1 and / or the second switch S2.
[0035] Example 1
[0036] Please see Figure 3 , Figure 3 This is a schematic diagram of the wide-amplitude audio input circuit of Embodiment 1 of this utility model.
[0037] In this embodiment, the amplitude amplification module 11 specifically includes: a first operational amplifier A1, a first resistor R1, a second resistor R2, a third resistor R3, and a first capacitor C1. The non-inverting input terminal of the first operational amplifier A1 is connected to the original audio signal Ui through the first resistor R1, and the inverting input terminal is grounded through the second resistor R2. The third resistor R3 and the first capacitor C1 are both connected across the inverting input terminal and the output terminal of the first operational amplifier A1. The output terminal of the first operational amplifier A1 outputs the amplified audio signal Uo1.
[0038] The first operational amplifier A1, the first resistor R1, the second resistor R2, and the third resistor R3 form a proportional amplifier circuit, and the first capacitor C1 serves as a voltage regulator and filter. Based on the circuit principle, it can be deduced that the amplified audio signal Uo1 and the original audio signal Ui satisfy the following relationship: In the formula, R2 and R3 represent the resistance values of the second resistor R2 and the third resistor R3, respectively. It can be seen that the amplitude amplification module 11 amplifies the amplitude of the original audio signal Ui, and the specific amplification factor can be adjusted by adjusting the resistance values of the second resistor R2 and the third resistor R3.
[0039] The amplitude attenuation module 12 specifically includes: a second operational amplifier A2, a fourth resistor R4, a fifth resistor R5, a third operational amplifier A3, a sixth resistor R6, a seventh resistor R7, and a second capacitor C2. The inverting input of the second operational amplifier A2 is connected to the original audio signal Ui through the fourth resistor R4, and its non-inverting input is grounded. The fifth resistor R5 is connected between the inverting input and output of the second operational amplifier A2. The inverting input of the third operational amplifier A3 is connected to the output of the second operational amplifier A2 through the sixth resistor R6, and its non-inverting input is grounded. The seventh resistor R7 and the second capacitor C2 are connected between the inverting input and output of the third operational amplifier A3. The output of the third operational amplifier A3 outputs an attenuated audio signal Uo2.
[0040] The second operational amplifier A2, the fourth resistor R4, the fifth resistor R5, the third operational amplifier A3, the sixth resistor R6, and the seventh resistor R7 form a two-stage proportional amplifier circuit, and the second capacitor C2 serves as a voltage regulator and filter. Based on the circuit principle, it can be deduced that the attenuated audio signal Uo2 and the original audio signal Ui satisfy the following relationship: In the formula, R4, R5, R6, and R7 represent the resistance values of the fourth resistor R4, the fifth resistor R5, the sixth resistor R6, and the seventh resistor R7, respectively. It can be seen that by adjusting the resistance values of the fourth resistor R4, the fifth resistor R5, the sixth resistor R6, and the seventh resistor R7, the following can be achieved: The amplitude attenuation module 12 can attenuate the amplitude of the original audio signal Ui. Furthermore, by adjusting the resistance values of the fourth resistor R4, the fifth resistor R5, the sixth resistor R6, and the seventh resistor R7, the specific attenuation factor can be adjusted.
[0041] The amplitude sampling module 14 specifically includes: a fourth operational amplifier A4, an eighth resistor R8, a ninth resistor R9, a first diode D1, a second diode D2, and a third capacitor C3. The inverting input of the fourth operational amplifier A4 is connected to the original audio signal Ui through the eighth resistor R8, and the non-inverting input is grounded. The ninth resistor R9 is connected between the inverting input and output of the fourth operational amplifier A4. The anode of the first diode D1 is connected to the output of the fourth operational amplifier A4, and the cathode is connected to the signal input of the judgment module 15. The anode of the second diode D2 is connected to the non-inverting input of the fourth operational amplifier A4, and the cathode is connected to the cathode of the first diode D1. One end of the third capacitor C3 is connected to the cathode of the first diode D1, and the other end is grounded. The cathode of the first diode D1 outputs the sampled amplitude Usmp to the signal input of the judgment module 15.
[0042] The fourth operational amplifier A4, the eighth resistor R8, and the ninth resistor R9 form a proportional amplifier circuit, making the voltage at the output of the fourth operational amplifier A4 proportional to the original audio signal Ui. The first diode D1 and the second diode D2 rectify the voltage at the output of the fourth operational amplifier A4 to extract the amplitude of the voltage at the output of the fourth operational amplifier A4, so that the sampling amplitude Usmp output from the cathode of the first diode D1 can reflect the amplitude of the original audio signal Ui.
[0043] The judgment module 15 is specifically a microcontroller, whose internal program stores a preset threshold. The judgment module 15 determines whether the amplitude of the original audio signal Ui is too large by comparing the sampled amplitude Usmp with the preset threshold. If the sampled amplitude Usmp is greater than or equal to the preset threshold, the amplitude of the original audio signal Ui is determined to be too large. In this case, the judgment module 15 outputs a control signal SEL to control the first switch S1 in the switching module 13 to open and the second switch S2 to open, thereby allowing the attenuated audio signal Uo2 to be transmitted as the equalized audio signal Uo to the post-processing module 2. If the sampled amplitude Usmp is less than the preset threshold, the amplitude of the original audio signal Ui is determined not to be too large. In this case, the judgment module 15 outputs a control signal SEL to control the first switch S1 in the switching module 13 to open and the second switch S2 to open, thereby allowing the amplified audio signal Uo1 to be transmitted as the equalized audio signal Uo to the post-processing module 2.
[0044] Example 2
[0045] Please see Figure 4 , Figure 4 This is a schematic diagram of the wide-amplitude audio input circuit of Embodiment 2 of this utility model. The structure of the wide-amplitude audio input circuit of Embodiment 2 is basically the same as that of Embodiment 1, except that: the first operational amplifier A1 and the fourth operational amplifier A4 are integrated in... Figure 4 The first dual operational amplifier chip U1 shown; the second operational amplifier A2 and the third operational amplifier A3 are integrated in Figure 4 In the second dual operational amplifier chip U2 shown; the first switch S1 and the second switch S2 of the switching module 13 are integrated in Figure 4 The analog switch chip U3 shown is used.
[0046] Specifically, the first dual operational amplifier chip U1 has its VCC pin connected to the positive power supply, its VEE pin connected to the negative power supply, its IN1+ pin being the non-inverting input of the first operational amplifier A1, its IN1- pin being the inverting input of the first operational amplifier A1, its OUT1 pin being the output of the first operational amplifier A1, its IN2+ pin being the non-inverting input of the fourth operational amplifier A4, its IN2- pin being the inverting input of the fourth operational amplifier A4, and its OUT2 pin being the output of the fourth operational amplifier A4.
[0047] Specifically, the second dual operational amplifier chip U2 has its VCC pin connected to the positive power supply, its VEE pin connected to the negative power supply, its IN1+ pin being the non-inverting input of the second operational amplifier A2, its IN1- pin being the inverting input of the second operational amplifier A2, its OUT1 pin being the output of the second operational amplifier A2, its IN2+ pin being the non-inverting input of the third operational amplifier A3, its IN2- pin being the inverting input of the third operational amplifier A3, and its OUT2 pin being the output of the third operational amplifier A3.
[0048] Specifically, the analog switch chip U3 has its VCC pin connected to a +3.3V power supply, its GND pin grounded, its CH0 pin connected to the amplified audio signal Uo1, its CH1 pin connected to the attenuated audio signal Uo2, its SEL pin connected to the control signal SEL output by the judgment module, and its COM pin outputting the equalized audio signal Uo to the subsequent processing module 2. The analog switch chip U3 is equivalent to a single-pole double-throw switch, and the level of the control signal SEL output by the judgment module determines whether the equalized audio signal Uo is the amplified audio signal Uo1 or the attenuated audio signal Uo2.
[0049] Furthermore, the first dual operational amplifier chip U1 and the second dual operational amplifier chip U2 are model NJM5532M(DMP-8), the analog switch chip U3 is model CH443K, and the judgment module 15 is model ESP32-C3.
[0050] Furthermore, the amplitude amplification module 11 adjusts the amplification factor of the original audio signal to 6dB, and the amplitude attenuation module 12 adjusts the attenuation factor of the original audio signal to 12dB.
[0051] Furthermore, the positive terminal of the power supply connected to the VCC pin of the first dual op-amp chip U1 and the second dual op-amp chip U2 is +8V, and the negative terminal of the power supply connected to the VEE pin of the first dual op-amp chip U1 and the second dual op-amp chip U2 is -8V.
[0052] This invention offers the following technical advantages: The wide-amplitude audio input circuit of this invention suppresses the amplitude of the original audio signal when the input sound amplitude is too high, and amplifies the amplitude of the original audio signal when the input sound amplitude is too low, resulting in a moderate amplitude of the equalized audio signal output to the subsequent processing module. This avoids damage to sensitive components caused by excessively large amplitude original audio signals, improving safety and extending circuit lifespan. Furthermore, it improves the post-processing effect of the audio signal, avoiding signal saturation distortion, ensuring clear microphone pickup, and providing a better user experience. Compared to existing audio input circuits, this invention significantly expands the variable range of input sound amplitude. Whether the user shouts loudly or whispers, the subsequent processing module can obtain a relatively balanced audio signal, improving not only the safety of the subsequent processing module but also enhancing the user experience.
[0053] The embodiments described above are merely examples of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and this utility model also intends to include these modifications and variations.
Claims
1. A wide range audio input circuit, characterized by, include: The amplitude amplification module amplifies the original audio signal to obtain an amplified audio signal; The amplitude attenuation module attenuates the original audio signal to obtain an attenuated audio signal. A switching module is connected to the output terminals of the amplitude amplification module and the amplitude attenuation module, and outputs the amplified audio signal or the attenuated audio signal as an equalized audio signal. An amplitude sampling module samples the amplitude of the original audio signal to obtain the sampled amplitude. The judgment module controls the switching module to output the amplified audio signal or the attenuated audio signal as an equalized audio signal based on the sampling amplitude.
2. The wide-amplitude audio input circuit according to claim 1, characterized in that: The switching module includes: a first switch disposed between the output terminal of the amplitude amplification module and the input terminal of the post-processing module, and a second switch disposed between the output terminal of the amplitude attenuation module and the input terminal of the post-processing module; The judgment module controls the switching module to output the amplified or attenuated audio signal as an equalized audio signal based on the sampling amplitude, specifically including: If the sampling amplitude is greater than or equal to a preset threshold, the first switch in the switching module is turned off and the second switch is turned on, so that the attenuated audio signal is output as an equalized audio signal. If the sampling amplitude is less than a preset threshold, the first switch in the switching module is turned on and the second switch is turned off, so that the amplified audio signal is output as an equalized audio signal.
3. The wide-amplitude audio input circuit according to claim 2, characterized in that: The judgment module is a comparator or a microcontroller; the first switch and the second switch are transistors or MOSFETs. The output terminal of the judgment module is connected to the base or gate of the first switch and the second switch.
4. The wide-amplitude audio input circuit according to claim 3, characterized in that: The amplitude amplification module, amplitude attenuation module, and amplitude sampling module are all proportional amplifier circuits based on operational amplifiers.
5. The wide-amplitude audio input circuit according to claim 4, characterized in that: The amplitude amplification module specifically includes: a first operational amplifier, a first resistor, a second resistor, a third resistor, and a first capacitor; the non-inverting input terminal of the first operational amplifier is connected to the original audio signal through the first resistor, and the inverting input terminal is grounded through the second resistor; the third resistor and the first capacitor are both connected across the inverting input terminal and the output terminal of the first operational amplifier; the output terminal of the first operational amplifier outputs the amplified audio signal.
6. The wide-amplitude audio input circuit according to claim 5, characterized in that: The amplitude attenuation module specifically includes: a second operational amplifier, a fourth resistor, a fifth resistor, a third operational amplifier, a sixth resistor, a seventh resistor, and a second capacitor; the inverting input terminal of the second operational amplifier is connected to the original audio signal through the fourth resistor, and the non-inverting input terminal is grounded; the fifth resistor is connected between the inverting input terminal and the output terminal of the second operational amplifier; the inverting input terminal of the third operational amplifier is connected to the output terminal of the second operational amplifier through the sixth resistor, and the non-inverting input terminal is grounded; the seventh resistor and the second capacitor are connected between the inverting input terminal and the output terminal of the third operational amplifier; the output terminal of the third operational amplifier outputs the attenuated audio signal.
7. The wide-amplitude audio input circuit according to claim 6, characterized in that: The amplitude sampling module specifically includes: a fourth operational amplifier, an eighth resistor, a ninth resistor, a first diode, a second diode, and a third capacitor; the inverting input of the fourth operational amplifier is connected to the original audio signal through the eighth resistor, and the non-inverting input is grounded; the ninth resistor is connected between the inverting input and output of the fourth operational amplifier; the anode of the first diode is connected to the output of the fourth operational amplifier; the anode of the second diode is connected to the non-inverting input of the fourth operational amplifier, and the cathode is connected to the cathode of the first diode; one end of the third capacitor is connected to the cathode of the first diode D1, and the other end is grounded; the cathode of the first diode outputs the sampled amplitude to the judgment module.
8. The wide-amplitude audio input circuit according to claim 7, characterized in that: The first operational amplifier and the fourth operational amplifier are integrated in a first dual operational amplifier chip; the second operational amplifier and the third operational amplifier are integrated in a second dual operational amplifier chip; the first switch and the second switch of the switching module are integrated in an analog switch chip.
9. The wide-amplitude audio input circuit according to claim 8, characterized in that: The first dual operational amplifier chip and the second dual operational amplifier chip are both model NJM5532M; the analog switch chip is model CH443K; the judgment module is a microcontroller, model ESP32-C3.
10. A microphone, characterized by Its internal circuitry includes: The wide-amplitude audio input circuit according to any one of claims 1-9, and the subsequent processing module; The audio input circuit is used to receive sound and convert it into a raw audio signal, and then perform gain control on the raw audio signal to obtain a balanced audio signal; The post-processing module is used to perform post-processing on the equalized audio signal.