A microphone with low-noise audio amplifier circuit

Abstract

This invention discloses a microphone with a low-noise audio amplification circuit, including a pickup module, an audio amplification module, and a SOC module. The pickup module and the SOC module are respectively connected to the audio amplification module. The pickup module is used to convert the collected sound signal into an audio signal. The audio amplification module includes a signal input unit, a signal amplification unit, and a bias circuit. The signal input unit is used to receive the audio signal and is connected to the signal amplification unit and the bias circuit. The signal amplification unit is used to amplify the audio signal, and the bias circuit is used to power the pickup module. This invention can achieve the effect of an operational amplifier, and the integration of the pickup module, audio amplification module, and SOC module reduces the circuit board footprint, thus miniaturizing the microphone product.

Description

Technical Field

[0001] This utility model relates to the field of audio processing technology, and in particular to a microphone with a low-noise audio amplification circuit. Background Technology

[0002] In existing technologies, microphone amplifier circuits built with discrete components generally employ a multi-stage amplifier topology. This approach has the following technical drawbacks: First, it requires a pre-amplifier impedance matching circuit, intermediate stage gain adjustment modules, and a final stage output buffer, resulting in more than 15 circuit nodes. Second, electromagnetic compatibility isolation zones must be reserved between each functional module, leading to redundant signal chain layout and low PCB space utilization in miniature microphone applications. This situation not only significantly increases BOM costs but also severely restricts the integration of peripheral functional modules.

[0003] Therefore, there is an urgent need to develop microphones with low-noise audio amplification circuits that have space compression characteristics in order to achieve the goals of reducing the footprint of the circuit board and miniaturizing the product. Utility Model Content

[0004] The main purpose of this invention is to propose a microphone with a low-noise audio amplification circuit, aiming to reduce the footprint of the circuit board and miniaturize the product.

[0005] To achieve the above objectives, this utility model proposes a microphone with a low-noise audio amplification circuit, comprising a pickup module, an audio amplification module, and a SOC module. The pickup module and the SOC module are respectively connected to the audio amplification module. The pickup module is used to convert the collected sound signal into an audio signal. The audio amplification module includes a signal input unit, a signal amplification unit, and a bias circuit. The signal input unit is used to receive the audio signal and is connected to the signal amplification unit and the bias circuit. The signal amplification unit is used to amplify the audio signal, and the bias circuit is used to power the pickup module.

[0006] In one embodiment, the signal input unit includes a first inductor, a second inductor, and a first capacitor; the pickup module includes a microphone; one end of the first inductor is connected to the positive terminal of the microphone; the other end of the second inductor is connected to one end of the first capacitor; the other end of the first capacitor is connected to the signal amplification unit; one end of the second inductor is connected to the negative terminal of the microphone; and the other end of the second inductor is grounded.

[0007] In one embodiment, the signal amplification unit includes a transistor and a second capacitor. The base of the transistor is connected to the signal input unit, the emitter of the transistor is connected to one end of the second capacitor, and the other end of the second capacitor is connected to the microphone input terminal.

[0008] In one embodiment, the bias circuit includes a first resistor, a third capacitor, a second resistor, and a third resistor. One end of the first resistor is connected to the base of the transistor. The third capacitor is connected in parallel with the second resistor. The other end of the first resistor is connected to one end of the third capacitor, one end of the second resistor, and one end of the third resistor, respectively. The other ends of the third capacitor and the second resistor are both grounded. The other end of the third resistor is connected to the SOC module.

[0009] In one embodiment, the microphone includes an antenna module connected to the SOC module.

[0010] In one embodiment, the antenna module includes an onboard antenna, a fourth resistor, an ESD transistor, a fourth capacitor, and a fifth capacitor. One end of the fourth resistor is connected to the RF feed point of the onboard antenna and the fourth capacitor, respectively. The other end of the fourth resistor is connected to one end of the ESD transistor and the fifth capacitor, respectively. The other end of the ESD transistor is connected to the ground feed point of the onboard antenna and grounded.

[0011] In one embodiment, the microphone includes a contact module connected to the SOC module, the contact module being used to connect the microphone's power supply.

[0012] In one embodiment, the microphone includes a battery module connected to the SOC module, the battery module being used to power the SOC module.

[0013] In one embodiment, the microphone includes an optocoupler indicator module connected to the SOC module.

[0014] In one embodiment, the microphone includes a button module connected to the SOC module, and the button module is used to turn the microphone on or off.

[0015] This invention receives the audio signal through a signal input unit, amplifies the audio signal through a signal amplification unit, and provides a bias voltage or bias current to the signal amplification unit through a bias circuit to achieve the effect of an operational amplifier. It integrates a pickup module, an audio amplification module, and a SOC module to reduce the footprint of the circuit board and make the microphone product miniaturized. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of a microphone module with a low-noise audio amplifier circuit.

[0018] Figure 2 This is the circuit diagram for the audio amplification module;

[0019] Figure 3 This is the circuit diagram of the antenna module;

[0020] Figure 4 This is the circuit diagram for the contact module;

[0021] Figure 5 This is the circuit diagram for the battery module;

[0022] Figure 6 This is the circuit diagram of the optocoupler indicator module;

[0023] Figure 7 This is the circuit diagram for the button module;

[0024] Figure 8 This is the circuit diagram of the SOC module.

[0025] Explanation of icon numbers:

[0026] 10. Sound pickup module; 20. Audio amplification module; 30. SOC module; 201. Signal input unit; 202. Signal amplification unit; 203. Bias circuit; L2. First inductor; L3. Second inductor; C15. First capacitor; 101. Microphone; Q2. Transistor; C23. Second capacitor; R26. First resistor; C3. Third capacitor; R9. Second resistor; R8. Third resistor; 40. Antenna module; 401. Onboard antenna; R3. Fourth resistor; ESD3. ESD tube; C16. Fourth capacitor; C17. Fifth capacitor; 50. Contact module; 60. Battery module; 70. Optocoupler indicator module; 80. Button module.

[0027] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0029] It should be noted that if the embodiments of this utility model involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0030] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, if the word "and / or" appears throughout the text, it means including three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution that simultaneously satisfies A and B. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0031] This invention proposes a microphone with a low-noise audio amplification circuit.

[0032] In the embodiments of this utility model, such as Figure 1 and Figure 8As shown, the microphone with a low-noise audio amplification circuit includes a pickup module 10, an audio amplification module 20, and a SOC module 30 (System on Chip). The pickup module 10 and the SOC module 30 are respectively connected to the audio amplification module 20. The pickup module 10 is used to convert the collected sound signal into an audio signal. The audio amplification module 20 includes a signal input unit 201, a signal amplification unit 202, and a bias circuit 203. The signal input unit 201 is used to receive the audio signal. The signal input unit 201 is connected to the signal amplification unit 202 and the bias circuit 203. The signal amplification unit 202 is used to amplify the audio signal. The bias circuit 203 is used to power the pickup module 10. The bias circuit 203 and the signal amplification unit 202 are respectively connected to the SOC chip U3 of the SOC module 30. The SOC chip U3 is a commonly available SOC main control chip.

[0033] This invention achieves the effect of an operational amplifier by receiving the audio signal through a signal input unit 201, amplifying the audio signal through a signal amplification unit 202, and providing a bias voltage or bias current to the signal amplification unit 202 through a bias circuit 203. It integrates a pickup module 10, an audio amplification module 20, and a SOC module 30 to reduce the footprint of the circuit board and make the microphone product miniaturized.

[0034] like Figure 2 As shown, the signal input unit 201 includes a first inductor L2, a second inductor L3, and a first capacitor C15. The pickup module 10 includes a microphone 101. One end of the first inductor L2 is connected to the positive terminal of the microphone 101. The other end of the second inductor L3 is connected to one end of the first capacitor C15. The other end of the first capacitor C15 is connected to the signal amplification unit 202. One end of the second inductor L3 is connected to the negative terminal of the microphone 101. The other end of the second inductor L3 is grounded.

[0035] The first inductor L2 and the second inductor L3 are used for filtering and impedance matching in signal transmission, reducing noise interference or performing appropriate impedance conversion in signal transmission. The first capacitor C15 transmits the audio signal picked up by the microphone 101 to the signal amplification unit 202, and also helps to remove the DC component. The microphone 101 is responsible for converting the sound wave signal into an electrical signal. The sound wave is transmitted to the internal circuit through the diaphragm of the microphone 101 and converted into a weak electrical signal.

[0036] The first capacitor C15 is connected to the signal amplification unit 202 and is used to transmit the signal from the pickup module 10 to the signal amplification unit 202. At the same time, it also serves to isolate the DC component. The other end of the second inductor L3 is grounded, which helps to stabilize the circuit and provide a reference ground for the signal, ensuring the correctness of signal processing.

[0037] The signal amplification unit 202 includes a transistor Q2 and a second capacitor C23. The base of transistor Q2 is connected to the signal input unit 201, and the emitter of transistor Q2 is connected to one end of the second capacitor C23. The other end of the second capacitor C23 is connected to the microphone input terminal. The base of transistor Q2 is connected to the signal input unit 201 to receive the audio signal transmitted from the pickup module 10. Using transistor Q2 as a signal amplifier, transistor Q2 amplifies the audio signal input to its base. Specifically, when transistor Q2 is working, the current change between its base and emitter affects the current at its collector, thereby amplifying the signal. The other end of the second capacitor C23 is connected to the microphone input terminal to transmit the amplified audio signal to the subsequent circuitry of the microphone. Due to the characteristics of a capacitor, it isolates direct current and only transmits alternating current signals, which helps protect subsequent circuitry from the influence of direct current.

[0038] The bias circuit 203 includes a first resistor R26, a third capacitor C3, a second resistor R9, and a third resistor R8. One end of the first resistor R26 is connected to the base of the transistor Q2. The third capacitor C3 is connected in parallel with the second resistor R9. The other end of the first resistor R26 is connected to one end of the third capacitor C3, one end of the second resistor R9, and one end of the third resistor R8, respectively. The other ends of the third capacitor C3 and the second resistor R9 are both grounded. The other end of the third resistor R8 is connected to the SOC module 30.

[0039] The bias circuit 203 provides stable operating conditions for transistor Q2, ensuring it operates in the linear amplification region and remains stable under various input signal conditions. By adjusting the current and voltage, the bias circuit 203 controls the base voltage and current of transistor Q2, preventing it from entering the saturation or cutoff region. This allows the signal amplifier to correctly amplify the input signal. The second resistor R9 and the first resistor R26 together form a voltage divider network, providing a stable bias voltage to the base of transistor Q2.

[0040] like Figure 3 As shown, the microphone includes an antenna module 40, which is connected to the SOC module 30. The antenna module 40 includes an onboard antenna 401, a fourth resistor R3, an ESD transistor ESD3, a fourth capacitor C16, and a fifth capacitor C17. One end of the fourth resistor R3 is connected to the RF feed point of the onboard antenna 401 and the fourth capacitor C16. The other end of the fourth resistor R3 is connected to one end of the ESD transistor ESD3 and the fifth capacitor C17. The other end of the ESD transistor ESD3 is connected to the ground feed point of the onboard antenna 401 and grounded.

[0041] Antenna module 40 adopts an integrated design of RF circuitry and LDS antenna, effectively reducing coupling interference and improving radiation efficiency. The main function of the microphone antenna module 40 is to receive wireless signals (such as Bluetooth and Wi-Fi signals) and process them through the connected SOC module 30. The various components in antenna module 40 work together to ensure effective signal reception, noise suppression, and circuit safety. Onboard antenna 401 is responsible for receiving radio wave signals; it is the core component of antenna module 40, converting electromagnetic signals into electrical signals for subsequent processing. The fourth resistor R3 limits current and adjusts the amplitude of the RF signal to match the onboard antenna 401 and the back-end circuitry, preventing excessively strong signals from damaging the circuitry. The fourth capacitor C16 is used for high-frequency signal coupling or filtering, ensuring that the signal received by onboard antenna 401 can be effectively transmitted to the back-end circuitry. It also helps filter out unnecessary high-frequency noise and stabilize signal transmission. The ESD transistor ESD3 protects the circuit from electrostatic discharge (ESD) damage. Since wireless devices may be affected by static electricity during use, the ESD tube ESD3 can release static electricity to the ground, thereby protecting other components in the circuit from damage caused by high voltage. Grounding the ESD tube ESD3 can effectively release static electricity through the ground wire, protecting the antenna module 40 and other circuits from damage.

[0042] like Figure 4 As shown, the microphone includes a contact module 50, which is connected to the SOC module 30. The contact module 50 is used to connect the microphone's power supply. The contact module 50 provides an electrical connection point, allowing an external power source to connect to the microphone system's SOC module 30. The contact module 50 ensures that the microphone receives the necessary power to operate normally. The contact module 50 includes a button K1 and a diode ESD1. One end of the button K1 is connected to the SOC module 30, and the other end of the button K1 is grounded. One end of the button K1 is also grounded through the diode ESD1.

[0043] like Figure 5As shown, the microphone includes a battery module 60, which is connected to the SOC module 30 and supplies power to the SOC module 30. The battery module 60 provides necessary power support, especially in situations where there is no external power supply (e.g., for a wireless microphone), by powering the SOC module 30 and other circuit components through its built-in battery. The positive terminal of the battery module 60 is connected to the SOC module 30. The positive terminal of the battery module 60 is also connected to the first pin of the battery protection chip U2 through one end of a resistor R10. The negative terminal of the battery is connected to the second and third pins of the battery protection chip U2. The other end of the resistor R10 is connected to the negative terminal of the battery module 60 through a capacitor C5. The fourth pin of the battery protection chip U2 is grounded. The battery protection chip U2 is a commonly available battery protection chip.

[0044] like Figure 6 As shown, the microphone includes an optocoupler indicator module 70, which is connected to the SOC module 30. The optocoupler indicator module 70 is used to indicate the microphone's operating status, such as illuminating an indicator light to show the microphone's power-on status. The negative terminals of the LEDs R, G, and B in the optocoupler indicator module 70 are grounded, and the positive terminals of the LEDs R, G, and B are connected to the SOC module 30 through resistors R17, R12, and R15.

[0045] like Figure 7 As shown, the microphone includes a button module 80, which is connected to the SOC module 30. The button module 80 is used to turn the microphone on or off. The button module 80 allows the user to manually control the microphone's on and off state.

[0046] Pins 2, 4, and 5 of SOC module 30 are connected to optocoupler indicator module 70. Pin 6 of SOC module 30 is connected to contact module 50 through resistor R11. Pin 6 of SOC module 30 is also grounded through capacitor C20. Pin 7 of SOC module 30 is grounded through capacitor C21. Pin 8 of SOC module 30 is grounded through capacitors C22 and C27. Pin 8 of SOC module 30 is also connected to power supply module, which is connected to battery module 60. Pin 9 of SOC module 30 is grounded. Pin 10 of SOC module 30 is connected to pin 11 of SOC module 30 through inductor L1. Pin 11 of SOC module 30 is grounded through capacitor C18. Pin 15 of SOC module 30 is connected to button module 80. Pin 16 of SOC module 30 is connected to antenna module 40. Pins 17 and 18 of SOC module 30 are connected to crystal oscillators. Pins 23 and 24 of SOC module 30 are connected to pickup module 10.

[0047] The above description is merely a preferred embodiment of this utility model and is not intended to limit the scope of this utility model. For those skilled in the art, this utility model can have various modifications, combinations, and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the scope of the claims of this utility model.

Claims

1. A microphone with a low-noise audio amplification circuit, characterized in that, The system includes a sound pickup module, an audio amplification module, and a SOC module. The sound pickup module and the SOC module are respectively connected to the audio amplification module. The sound pickup module is used to convert the collected sound signal into an audio signal. The audio amplification module includes a signal input unit, a signal amplification unit, and a bias circuit. The signal input unit is used to receive the audio signal and is connected to the signal amplification unit and the bias circuit. The signal amplification unit is used to amplify the audio signal, and the bias circuit is used to supply power to the sound pickup module.

2. The microphone as described in claim 1, characterized in that, The signal input unit includes a first inductor, a second inductor, and a first capacitor. The pickup module includes a microphone. One end of the first inductor is connected to the positive terminal of the microphone. The other end of the second inductor is connected to one end of the first capacitor. The other end of the first capacitor is connected to the signal amplification unit. One end of the second inductor is connected to the negative terminal of the microphone. The other end of the second inductor is grounded.

3. The microphone as described in claim 1, characterized in that, The signal amplification unit includes a transistor and a second capacitor. The base of the transistor is connected to the signal input unit, the emitter of the transistor is connected to one end of the second capacitor, and the other end of the second capacitor is connected to the microphone input terminal.

4. The microphone as described in claim 3, characterized in that, The bias circuit includes a first resistor, a third capacitor, a second resistor, and a third resistor. One end of the first resistor is connected to the base of the transistor. The third capacitor is connected in parallel with the second resistor. The other end of the first resistor is connected to one end of the third capacitor, one end of the second resistor, and one end of the third resistor, respectively. The other ends of the third capacitor and the second resistor are both grounded. The other end of the third resistor is connected to the SOC module.

5. The microphone as claimed in claim 1, characterized in that, The microphone includes an antenna module, which is connected to the SOC module.

6. The microphone as described in claim 5, characterized in that, The antenna module includes an onboard antenna, a fourth resistor, an ESD diode, a fourth capacitor, and a fifth capacitor. One end of the fourth resistor is connected to the RF feed point of the onboard antenna and the fourth capacitor, respectively. The other end of the fourth resistor is connected to one end of the ESD diode and the fifth capacitor, respectively. The other end of the ESD diode is connected to the ground feed point of the onboard antenna and grounded.

7. The microphone as claimed in claim 1, characterized in that, The microphone includes a contact module connected to the SOC module, and the contact module is used to connect the microphone's power supply.

8. The microphone as claimed in claim 1, characterized in that, The microphone includes a battery module connected to the SOC module, and the battery module is used to power the SOC module.

9. The microphone as claimed in claim 1, characterized in that, The microphone includes an optocoupler indicator module, which is connected to the SOC module.

10. The microphone as claimed in claim 1, characterized in that, The microphone includes a button module, which is connected to the SOC module and is used to turn the microphone on or off.

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