A voice module for serial communication

Abstract

The utility model relates to a kind of voice module of serial communication, belong to voice equipment technical field, including voice input module, main control module, voice synthesis module and voice amplification circuit, voice input module includes analog interface J1, signal conditioning circuit, double on-off quantity interface J2 and isolation circuit;Analog interface J1 is connected to the first input end of main control module by signal conditioning circuit, double on-off quantity interface J2 is connected to the second input end of main control module by isolation circuit;The input end of voice synthesis module is connected to the output end of main control module, and the output end of voice synthesis module is connected to external loudspeaker B1 by voice amplification circuit.The utility model can simultaneously collect analog voice signal and complex on-off control signal by setting analog interface J1 and double on-off quantity interface J2, greatly widen the application range of voice module, so that it can be applied to the field of higher requirement for input signal diversity, such as intelligent customer service, vehicle-mounted system.

Description

Technical Field

[0001] This utility model belongs to the field of voice equipment technology, specifically relating to a serial communication voice module. Background Technology

[0002] With the rapid development of intelligent devices, voice interaction has become a key requirement in fields such as smart homes, industrial control, and vehicle systems. Serial communication, due to its advantages of simple wiring, low cost, and strong anti-interference capabilities, is widely used in data interaction between voice modules and external devices. However, existing serial communication voice modules still have many technical problems in practical applications, especially in signal input and processing.

[0003] Specifically, some modules with dual analog and digital input interfaces lack effective signal optimization structures for their analog interfaces. Analog voice signals are susceptible to external electromagnetic interference and line noise during transmission, leading to signal distortion, reduced signal-to-noise ratio, and insufficient accuracy of the voice data received by the main control module, thus affecting subsequent voice processing. Simultaneously, the digital interfaces and the main control module often use direct electrical connections without isolation protection. Electrical noise introduced during digital signal transmission can easily be conducted to the main control module, interfering with its normal operation, reducing overall module stability, and even causing main control module failure. Utility Model Content

[0004] The purpose of this invention is to address the aforementioned deficiencies in the existing technology by providing a serial communication voice module, comprising a voice input module, a main control module, a voice synthesis module, and a voice amplification circuit. The voice input module includes an analog interface J1, a signal conditioning circuit, a dual-switch interface J2, and an isolation circuit. The analog interface J1 is connected to the first input terminal of the main control module through the signal conditioning circuit, and the dual-switch interface J2 is connected to the second input terminal of the main control module through the isolation circuit. The input terminal of the voice synthesis module is connected to the output terminal of the main control module, and the output terminal of the voice synthesis module is connected to an external speaker B1 through the voice amplification circuit.

[0005] Further improvements to this technical solution include a signal conditioning circuit comprising an adjustable resistor R1, a resistor R2, a Zener diode D1, a resistor R3, a resistor R4, a capacitor C1, an amplifier U1, a resistor R5, a resistor R6, an amplifier U2, a resistor R7, a resistor R8, a resistor R9, a resistor R10, a capacitor C2, a diode D2, and a diode D3. The first terminal of adjustable resistor R1, the first terminal of resistor R2, and the cathode of Zener diode D1 are all connected to the first pin of analog interface J1. The second terminal of adjustable resistor R1, the second terminal of resistor R2, the anode of Zener diode, the second pin of analog interface J1, and the third pin of analog interface J1 are all grounded. The movable terminal of resistor R1 is connected to the first terminal of resistor R3 and the first terminal of resistor R4. The second terminal of resistor R3 and the first terminal of capacitor C1 are both connected to the non-inverting input of amplifier U1. The second terminal of resistor R4 and the second terminal of capacitor C1 are both grounded. The output terminal of amplifier U1 is connected to the inverting input of amplifier U1 and the first terminal of resistor R5. The second end of resistor R5 is connected to the non-inverting input of amplifier U2 and the first end of resistor R6. The second end of resistor R6 is connected to the power supply. The inverting input of amplifier U2 is grounded through resistor R7. The output of amplifier U2 is connected to the first ends of resistors R8 and R9. The second end of resistor R8 is connected to the inverting input of amplifier U2. The second end of resistor R9 is connected to the first end of resistor R10, the first end of capacitor C2, the cathode of diode D2, the anode of diode D3, and the main control module. The second ends of resistor R10, capacitor C2, and diode D2 are all grounded. The cathode of diode D3 is connected to the power supply.

[0006] Further improvements to this technical solution include an isolation circuit comprising resistors R11 and R12, LED1 and LED2, resistor R13, diode D4, capacitor C3, MOSFET Q1, optocoupler chip U3, resistors R14 and R15. The first end of resistor R11 is connected to the first pin of the dual-switch interface J2. The second end of resistor R11 is connected to the second pin of the dual-switch interface J2, the first end of capacitor C3, the cathode of diode D4, the first end of resistor R13, and the gate of MOSFET Q1. The second end of capacitor C3, the anode of diode D4, the second end of resistor R13, and the source of MOSFET Q1 are all grounded. The first end of resistor R12 is connected to the second pin of the dual-switch interface J2 and the anode of LED1. The second end of resistor R12 is connected to the anode of LED2. The cathodes of LED1 and LED2 are both connected to the third pin of the dual-switch interface J2 and grounded. The drain of MOSFET Q1 is connected to the cathode of the light-emitting terminal of optocoupler chip U3. The anode of the light-emitting terminal of optocoupler chip U3 is connected to the power supply through resistor R14. The collector of the light-receiving terminal of optocoupler chip U3 is connected to the power supply. The emitter of the light-receiving terminal of optocoupler chip U3 is connected to the first end of resistor R15 and the main control module. The second end of resistor R15 is grounded.

[0007] A further improvement to this technical solution is that the optocoupler chip U3 adopts the HCPL2201 optocoupler chip.

[0008] Further improvements to this technical solution include a voice amplification circuit comprising resistor R16, capacitor C4, capacitor C5, resistor R17, resistor R18, capacitor C8, capacitor C6, capacitor C7, resistor R19, operational amplifier U4, capacitor C9, resistor R20, adjustable resistor R21, resistor R22, resistor R23, capacitor C10, inductor L1, and capacitor C11. The first terminals of resistor R16, capacitor C4, and capacitor C5 are all connected to the output of the speech synthesis module. The second terminal of capacitor C4 is grounded. The second terminal of resistor R16 is connected to the power supply. The first terminals of resistor R17, capacitor C6, and capacitor C7 are connected to the power supply. The second terminals of capacitor C6 and capacitor C7 are grounded. The second terminal of resistor R17 is connected to the first terminals of resistor R18 and capacitor C8. The second terminals of resistor R18 and capacitor C8 are both grounded. The second terminal of capacitor C5 is connected to the first pin of operational amplifier U4, the first terminal of capacitor C9, the first terminal of resistor R20, and the adjustable resistor R2 through resistor R19. The first terminal of 1 is connected to the active terminal of the adjustable resistor R21. The second terminal of resistor R20 is connected to the first terminal of resistor R22. The second terminals of capacitor C9, adjustable resistor R21, and resistor R22 are all connected to the second pin of operational amplifier U4. The third pin of operational amplifier U4 is connected to the second terminal of resistor R17 and the first terminal of resistor R23. The second terminal of resistor R23 is connected to the first terminal of capacitor C10 and the first terminal of inductor L1. The second terminal of capacitor C10 is grounded. The second terminal of inductor L1 is connected to the first terminal of capacitor C11 and the first pin of external speaker B1. The second terminal of capacitor C11 and the second pin of external speaker B1 are both grounded.

[0009] Further improvements to this technical solution include the use of an ESP32-C3 main control chip in the main control module.

[0010] A further improvement to this technical solution is that the speech synthesis module uses the SNR9816 speech synthesis chip.

[0011] Further improvements to this technical solution include a WIFI module, through which the main control module connects to an external terminal.

[0012] The beneficial effects of this utility model are as follows: In the signal conditioning circuit, a circuit composed of adjustable resistors R1 and R2, and a Zener diode D1, performs preliminary processing on the analog voice signal input from the analog interface J1. The Zener diode's voltage regulation characteristics prevent excessive voltage from damaging subsequent circuits, while the adjustable resistors allow for signal amplitude adjustment. The signal then passes through an amplification and filtering circuit composed of amplifiers U1 and U2, effectively suppressing external electromagnetic interference and line noise, reducing signal distortion, improving the signal-to-noise ratio, and ensuring the main control module receives accurate and reliable voice data, thereby enhancing the subsequent voice processing performance.

[0013] The isolation circuit consists of resistors R11-R15, LEDs LED1 and LED2, diode D4, capacitor C3, MOSFET Q1, and optocoupler chip U3. When a switching signal is input through the dual switching interface J2, MOSFET Q1 performs preliminary signal processing, and then optocoupler chip U3 achieves electrical isolation before transmitting the switching signal to the main control module. This isolation mechanism effectively prevents electrical noise introduced during switching signal transmission from being conducted to the main control module, avoiding interference with the normal operation of the main control module, greatly improving the overall stability of the module, and reducing the probability of main control module failure.

[0014] The voice amplification circuit performs targeted processing on the output signal of the voice synthesis module. Operational amplifier U4, together with adjustable resistor R21, forms an adjustable gain amplification structure, which can control the signal gain between 20dB and 60dB according to actual needs, ensuring that the signal power meets the driving requirements. Capacitors C4, C6, C7, C8, C10, and C11, together with inductor L1, form a multi-stage filtering network, which sequentially filters out high-frequency interference, low-frequency noise, and harmonic components, reducing signal distortion. The final audio signal output to external speaker B1 has high purity and appropriate volume, and can achieve clear voice playback even in complex environments, making it suitable for various application scenarios such as intelligent customer service and in-vehicle systems.

[0015] Furthermore, the design principle of this utility model is reliable, the structure is simple, and it has a very wide range of application prospects.

[0016] It is evident that this utility model has outstanding substantive features and significant progress compared with the prior art, and the beneficial effects of its implementation are also obvious. Attached Figure Description

[0017] To more clearly illustrate the technical solution of this utility model, the drawings used in the description 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 these drawings without creative effort.

[0018] Figure 1 This is a schematic block diagram of the voice module.

[0019] Figure 2 This is a schematic diagram of a signal conditioning circuit.

[0020] Figure 3 This is a schematic diagram of an isolation circuit.

[0021] Figure 4 This is a schematic diagram of a voice amplifier circuit.

[0022] 110 is the voice input module, J1 is the analog interface, 111 is the signal conditioning circuit, J2 is the dual switch interface, 112 is the isolation circuit, 120 is the main control module, 130 is the voice synthesis module, and 140 is the voice amplification circuit. Detailed Implementation

[0023] To make the objectives, features, and advantages of this utility model more apparent and understandable, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings of the specific embodiments. Obviously, the embodiments described below are only some embodiments of this utility model, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

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

[0025] like Figure 1 As shown, this utility model provides a serial communication voice module, including a voice input module, a main control module, a voice synthesis module, and a voice amplification circuit. The voice input module includes an analog interface J1, a signal conditioning circuit, a dual-switch interface J2, and an isolation circuit. The analog interface J1 is connected to the first input terminal of the main control module through the signal conditioning circuit, and the dual-switch interface J2 is connected to the second input terminal of the main control module through the isolation circuit. The input terminal of the voice synthesis module is connected to the output terminal of the main control module, and the output terminal of the voice synthesis module is connected to an external speaker B1 through the voice amplification circuit. The main control module uses an ESP32-C3 main control chip, and the voice synthesis module uses an SNR9816 voice synthesis chip.

[0026] like Figure 2As shown, the signal conditioning circuit includes adjustable resistor R1, resistor R2, Zener diode D1, resistor R3, resistor R4, capacitor C1, amplifier U1, resistor R5, resistor R6, amplifier U2, resistor R7, resistor R8, resistor R9, resistor R10, capacitor C2, diode D2, and diode D3. The first terminal of adjustable resistor R1, the first terminal of resistor R2, and the cathode of Zener diode D1 are all connected to the first pin of analog interface J1. The second terminal of adjustable resistor R1, the second terminal of resistor R2, the anode of Zener diode, the second pin of analog interface J1, and the third pin of analog interface J1 are all grounded. The movable terminal of resistor R1 is connected to the first terminal of resistor R3 and the first terminal of resistor R4. The second terminal of resistor R3 and the first terminal of capacitor C1 are both connected to the non-inverting input of amplifier U1. The second terminals of resistor R4 and capacitor C1 are both grounded. The output terminal of amplifier U1 is connected to the inverting input terminal of amplifier U1 and the first terminal of resistor R5. The second terminal of resistor R5 is connected to the non-inverting input terminal of amplifier U2 and the first terminal of resistor R6. The second terminal of resistor R6 is connected to the power supply. The inverting input terminal of amplifier U2 is grounded through resistor R7. The output terminal of amplifier U2 is connected to the first terminals of resistor R8 and resistor R9. The second terminal of resistor R8 is connected to the inverting input terminal of amplifier U2. The second terminal of resistor R9 is connected to the first terminal of resistor R10, the first terminal of capacitor C2, the cathode of diode D2, the anode of diode D3, and the main control module. The second terminals of resistor R10, capacitor C2, and diode D2 are all grounded. The cathode of diode D3 is connected to the power supply.

[0027] Specifically, the input protection and voltage divider section: The first pin of the analog interface J1 serves as the signal input terminal, connected to the first terminals of adjustable resistor R1 and R2, and the cathode of Zener diode D1, respectively. The second and third pins of the analog interface J1 are both grounded, forming the circuit reference ground.

[0028] The positive terminal of the Zener diode D1 is grounded. Its function is to limit the voltage amplitude of the input signal, prevent excessive voltage from damaging subsequent circuit components, and play an overvoltage protection role.

[0029] The second terminal of resistor R2 is grounded, forming a voltage divider circuit with the adjustable resistor R1. The second terminal of the adjustable resistor R1 is grounded, and its movable terminal can be adjusted to change the resistance value connected to the circuit, thereby adjusting the voltage division ratio of the input signal and achieving preliminary adjustment of the input signal amplitude to adapt to different ranges of input signals.

[0030] Filtering and first-stage amplification section: The signal output from the movable terminal of the adjustable resistor R1 is split into two paths, which are connected to the first terminals of resistors R3 and R4, respectively. The second terminal of resistor R4 is grounded, and together with resistor R3, it forms a voltage divider to further adjust the signal amplitude.

[0031] The second terminal of resistor R3 is connected to the first terminal of capacitor C1, and together they are connected to the non-inverting input of amplifier U1. The second terminal of capacitor C1 is grounded, forming an RC low-pass filter circuit with resistor R3 to filter out high-frequency noise in the input signal, making the signal smoother.

[0032] Amplifier U1 adopts a voltage follower structure, with its output terminal directly connected to the inverting input terminal. This enables the conversion of high-impedance input and low-impedance output of the input signal, serving as a buffer and isolation mechanism to prevent subsequent circuits from affecting the signal of the preceding stage.

[0033] Second-stage amplification and bias section: The output of amplifier U1 is connected to the first terminal of resistor R5. The second terminal of resistor R5 is split into two paths: one path connects to the non-inverting input of amplifier U2, and the other path connects to the first terminal of resistor R6. The second terminal of resistor R6 is connected to a power supply (e.g., +5V) to provide a suitable DC bias voltage to the non-inverting input of amplifier U2, ensuring that amplifier U2 operates in the normal linear amplification region.

[0034] The inverting input of amplifier U2 is grounded through resistor R7 and connected to the output of amplifier U2 through resistor R8. Resistors R7 and R8 form a feedback network, which together determine the amplification factor of amplifier U2 (the amplification factor is calculated by the formula 1 + R8 / R7), thereby amplifying the signal again to meet the signal amplitude requirements of the main control module.

[0035] Output filtering and limiting section: The output terminal of amplifier U2 is connected to the first terminal of resistor R9. The second terminal of resistor R9 serves as the output terminal of the signal conditioning circuit and is connected to the main control module. It is also connected to the first terminal of resistor R10, the first terminal of capacitor C2, the negative terminal of diode D2, and the positive terminal of diode D3.

[0036] The second terminals of resistor R10 and capacitor C2 are both grounded, forming an RC low-pass filter circuit to filter the amplified signal again and further suppress noise.

[0037] The anode of diode D2 is grounded, and the cathode of diode D3 is connected to the power supply (e.g., +3.3V). Together, they form a clamping circuit. When the output signal voltage is higher than the power supply voltage, diode D3 conducts, clamping the voltage near the power supply voltage. When the output signal voltage is lower than ground potential, diode D2 conducts, clamping the voltage near ground potential. This limits the range of signal voltage output to the main control module, preventing damage to the main control module from excessively high or low voltages.

[0038] The analog interface J1 is connected to the main control module through a signal conditioning circuit. This circuit filters, amplifies, and stabilizes the analog voice signal, effectively suppressing noise interference, improving signal quality, and ensuring that the main control module receives a clear and accurate voice signal.

[0039] In the signal conditioning circuit, a circuit composed of adjustable resistors R1 and R2, and a Zener diode D1, performs preliminary processing on the analog voice signal input from the analog interface J1. The Zener diode's voltage regulation characteristics prevent excessive voltage from damaging subsequent circuits, while the adjustable resistors allow for signal amplitude adjustment. The signal then passes through an amplification and filtering circuit composed of amplifiers U1 and U2, effectively suppressing external electromagnetic interference and line noise, reducing signal distortion, improving the signal-to-noise ratio, and ensuring the main control module receives accurate and reliable voice data, thereby enhancing the subsequent voice processing performance.

[0040] like Figure 3As shown, the isolation circuit includes resistors R11 and R12, LED1 and LED2, resistor R13, diode D4, capacitor C3, MOSFET Q1, optocoupler U3, resistors R14 and R15. The first terminal of resistor R11 is connected to the first pin of the dual-switch interface J2. The second terminal of resistor R11 is connected to the second pin of the dual-switch interface J2, the first terminal of capacitor C3, the cathode of diode D4, the first terminal of resistor R13, and the gate of MOSFET Q1. The second terminal of capacitor C3, the anode of diode D4, the second terminal of resistor R13, and the source of MOSFET Q1 are all grounded. The first terminal of resistor R12 is connected to the second pin of the dual-switch interface J2 and the positive terminal of LED1. The second terminal of resistor R12 is connected to the positive terminal of LED2. The negative terminals of both LED1 and LED2 are connected to the third pin of the dual-switch interface J2 and grounded. The drain of MOSFET Q1 is connected to the negative terminal of the light-emitting end of optocoupler chip U3. The positive terminal of the light-emitting end of optocoupler chip U3 is connected to the power supply through resistor R14. The collector of the light-receiving end of optocoupler chip U3 is connected to the power supply. The emitter of the light-receiving end of optocoupler chip U3 is connected to the first terminal of resistor R15 and the main control module. The second terminal of resistor R15 is grounded. The optocoupler chip U3 is an HCPL2201 model.

[0041] Specifically, the switch signal input and indication section: The first and second pins of the dual-switch interface J2 are signal input terminals, and the third pin is a common ground terminal. The first end of resistor R11 is connected to the first pin of the dual-switch interface J2, and the second end is connected to the second pin of the dual-switch interface J2, forming an input path for the switch signal.

[0042] The first terminal of resistor R12 is connected to the second pin of the dual-switch interface J2 and the positive terminal of LED1, while the second terminal is connected to the positive terminal of LED2. The negative terminals of both LED1 and LED2 are connected to the third pin of the dual-switch interface J2 and grounded. When a switch signal is input to the dual-switch interface J2, LED1 or LED2 lights up according to the signal status, visually indicating the input status of the switch signal (e.g., LED1 corresponds to the first switch signal, and LED2 corresponds to the second switch signal). Resistor R12 provides current limiting protection for the LEDs to prevent overcurrent damage.

[0043] Signal preprocessing and driving section: The second pin of the dual-switch interface J2 is simultaneously connected to the first terminal of capacitor C3, the cathode of diode D4, the first terminal of resistor R13, and the gate of MOSFET Q1. The second terminal of capacitor C3 is grounded to filter out high-frequency interference in the input signal and stabilize the signal input to the gate of MOSFET Q1; the anode of diode D4 is grounded to clamp the reverse voltage of the gate of MOSFET Q1 and prevent the gate from being damaged due to reverse overvoltage.

[0044] The first end of resistor R13 is connected to the gate of MOSFET Q1, and the second end is grounded (signal ground) together with the source of MOSFET Q1. Resistor R13 provides a pull-down resistor for the gate of MOSFET Q1 to ensure that MOSFET Q1 is reliably turned off when there is no input signal.

[0045] The field-effect transistor Q1 is an N-channel enhancement-mode MOSFET. Its gate receives a pre-processed switching signal, its source is grounded, and its drain is connected to the negative terminal of the light-emitting terminal of the optocoupler chip U3, serving as the driving switching device for the optocoupler chip U3. When the input switching signal is high, the gate voltage of the field-effect transistor Q1 increases and it conducts, providing a path for the light-emitting terminal of the optocoupler chip U3. When the input signal is low, the field-effect transistor Q1 is cut off, and no current flows through the light-emitting terminal of the optocoupler chip U3.

[0046] Opto-isolation and signal output section: The optocoupler chip U3 uses a high-speed optocoupler of model HCPL2201, which integrates light-emitting diodes and phototransistors. It achieves electrical isolation between the input side (signal ground) and the output side (main control module side) through optical signal transmission. The isolation voltage can reach 2500Vrms, effectively blocking common-mode interference between the two sides.

[0047] The positive terminal of the light-emitting end (input terminal) of the optocoupler chip U3 is connected to the power supply (e.g., +5V power supply) through resistor R14, and the negative terminal is connected to the drain of the field-effect transistor Q1; resistor R14 provides current limiting protection for the light-emitting diode of the optocoupler chip U3 to ensure that its operating current is within the rated range (typical value is 5-10mA).

[0048] The collector of the light-receiving (output) end of the optocoupler chip U3 is connected to a power supply (e.g., +3.3V, matching the operating voltage of the main control module). The emitter is connected to the first terminal of resistor R15 and the signal input terminal of the main control module, while the second terminal of resistor R15 is grounded. When the light-emitting end of the optocoupler chip U3 is turned on, the phototransistor at the light-receiving end is turned on, and the emitter outputs a low-level signal to the main control module. When the light-emitting end is turned off, the phototransistor at the light-receiving end is turned off, and the emitter is pulled up to the power supply voltage through resistor R15, outputting a high-level signal to the main control module, thereby achieving isolated transmission of switching signals.

[0049] The dual switch interface J2 is connected to the main control module through an isolation circuit, which can achieve electrical isolation and prevent electrical noise introduced during the transmission of switch signals from interfering with the main control module, thereby enhancing the stability and reliability of the system.

[0050] The isolation circuit consists of resistors R11-R15, LEDs LED1 and LED2, diode D4, capacitor C3, MOSFET Q1, and optocoupler chip U3. When a switching signal is input through the dual switching interface J2, MOSFET Q1 performs preliminary signal processing, and then optocoupler chip U3 achieves electrical isolation before transmitting the switching signal to the main control module. This isolation mechanism effectively prevents electrical noise introduced during switching signal transmission from being conducted to the main control module, avoiding interference with the normal operation of the main control module, greatly improving the overall stability of the module, and reducing the probability of main control module failure.

[0051] In addition, the voice input module of this utility model is equipped with an analog interface J1 and a dual switch interface J2, which can simultaneously acquire analog voice signals and complex switch control signals, greatly expanding the application range of the voice module and making it suitable for fields with high requirements for the diversity of input signals, such as intelligent customer service and vehicle systems.

[0052] like Figure 4As shown, the voice amplification circuit includes resistor R16, capacitors C4 and C5, resistors R17 and R18, capacitors C8, C6, C7, and R19, operational amplifier U4, capacitor C9, resistor R20, adjustable resistors R21, R22, and R23, capacitor C10, inductor L1, and capacitor C11. The first terminals of resistors R16, C4, and C5 are all connected to the output of the voice synthesis module. The second terminal of capacitor C4 is grounded. The second terminal of resistor R16 is connected to the power supply. The first terminals of resistors R17, C6, and C7 are connected to the power supply. The second terminals of capacitors C6 and C7 are grounded. The second terminal of resistor R17 is connected to the first terminal of resistor R18 and capacitor C8. The second terminals of resistor R18 and capacitor C8 are also connected to the power supply. The second terminal of capacitor C5 is connected to the first pin of operational amplifier U4, the first terminal of capacitor C9, the first terminal of resistor R20, the first terminal of adjustable resistor R21, and the movable terminal of adjustable resistor R21 through resistor R19. The second terminal of resistor R20 is connected to the first terminal of resistor R22. The second terminals of capacitor C9, adjustable resistor R21, and resistor R22 are all connected to the second pin of operational amplifier U4. The third pin of operational amplifier U4 is connected to the second terminal of resistor R17 and the first terminal of resistor R23. The second terminal of resistor R23 is connected to the first terminal of capacitor C10 and the first terminal of inductor L1. The second terminal of capacitor C10 is grounded. The second terminal of inductor L1 is connected to the first terminal of capacitor C11 and the first pin of external speaker B1. The second terminal of capacitor C11 and the second pin of external speaker B1 are both grounded.

[0053] Specifically, the signal input and preprocessing section: The output of the speech synthesis module serves as the audio signal input, connected to the first terminals of resistor R16, capacitor C4, and capacitor C5, respectively. The second terminal of capacitor C4 is grounded, forming a high-frequency filtering branch for the input signal. This branch filters out high-frequency interference components in the speech signal, preventing interference signals from entering subsequent amplification circuits.

[0054] The second terminal of resistor R16 is connected to the power supply (e.g., +5V), and simultaneously connected to the first terminal of resistor R17, the first terminal of capacitor C6, and the first terminal of capacitor C7. The second terminals of capacitors C6 and C7 are both grounded, forming a power supply filter circuit (e.g., C6 is a 10μF electrolytic capacitor to filter low-frequency ripple, and C7 is a 0.1μF ceramic capacitor to filter high-frequency noise), providing a stable operating voltage for the entire amplifier circuit.

[0055] The second end of resistor R17 is connected to the first end of resistor R18 and the first end of capacitor C8. The second ends of resistor R18 and capacitor C8 are both grounded. The three together form a voltage divider bias and filter network, which provides a stable reference bias voltage for operational amplifier U4 and further filters out noise introduced by the power supply.

[0056] Audio amplification and gain adjustment section: The second end of capacitor C5 serves as the coupling end for the audio signal and is connected to the first pin (non-inverting input) of operational amplifier U4 through resistor R19. Capacitor C5 is a DC blocking coupling capacitor, used to block the DC component in the output signal of the speech synthesis module and only allow the AC audio signal to enter the amplifier circuit.

[0057] The first pin (non-inverting input) of operational amplifier U4 is simultaneously connected to the first terminal of capacitor C9, the first terminal of resistor R20, the first terminal of adjustable resistor R21, and the movable terminal. The second terminal of capacitor C9 is connected to the second pin (inverting input) of operational amplifier U4, forming a phase compensation capacitor to prevent self-oscillation of the operational amplifier at high frequencies and ensure stable circuit operation.

[0058] The second end of resistor R20 is connected to the first end of resistor R22. The second ends of both adjustable resistor R21 and resistor R22 are connected to the second pin (inverting input) of operational amplifier U4. Resistors R20, R21, and R22 together form the negative feedback network of operational amplifier U4. By adjusting the position of the movable end of adjustable resistor R21, the feedback coefficient can be changed, thereby adjusting the gain of the entire amplifier circuit (for example, the gain range can be set to 20dB-60dB) to adapt to different volume requirements.

[0059] The third pin (output terminal) of operational amplifier U4 is connected to the first terminal of resistor R23 to amplify the power of the audio signal. The amplitude of the amplified signal can meet the basic requirements for driving a speaker.

[0060] Output filtering and speaker driver section: The second end of resistor R23 is connected to the first end of capacitor C10 and the first end of inductor L1. The second end of capacitor C10 is grounded, forming an RC high-pass filter circuit with resistor R23 to filter out low-frequency noise in the amplified signal and avoid low-frequency interference causing noise from the speaker.

[0061] The second terminal of inductor L1 is connected to the first terminal of capacitor C11 and the first pin of external speaker B1. Both the second terminal of capacitor C11 and the second terminal of speaker B1 are grounded. Inductor L1 and capacitor C11 form an LC low-pass filter circuit (e.g., with the resonant frequency set to 20kHz) to filter out high-frequency harmonic components, making the audio signal output to the speaker cleaner, while protecting the speaker from damage by high-frequency signals.

[0062] An external speaker B1 (e.g., an 8Ω, 0.5W speaker) receives the filtered and amplified signal, converts the electrical signal into a sound signal, and enables clear speech playback.

[0063] The voice amplification circuit performs targeted processing on the output signal of the voice synthesis module. Operational amplifier U4, together with adjustable resistor R21, forms an adjustable gain amplification structure, which can control the signal gain between 20dB and 60dB according to actual needs, ensuring that the signal power meets the driving requirements. Capacitors C4, C6, C7, C8, C10, and C11, together with inductor L1, form a multi-stage filtering network, which sequentially filters out high-frequency interference, low-frequency noise, and harmonic components, reducing signal distortion. The final audio signal output to external speaker B1 has high purity and appropriate volume, and can achieve clear voice playback even in complex environments, making it suitable for various application scenarios such as intelligent customer service and in-vehicle systems.

[0064] In addition, the voice module also includes a Wi-Fi module. The main control module connects to the external terminal via the Wi-Fi module, and communication between the main control module and the Wi-Fi module is achieved through a UART (Universal Asynchronous Receiver / Transmitter) interface. The main control module establishes a communication connection with the external terminal through this Wi-Fi module, thereby realizing functions such as remote control, data uploading, and command reception. Through the above structure and working method, the Wi-Fi module enables wireless data interaction between the main control module and the external terminal, allowing users to remotely monitor the device's operating status and issue control commands, improving the device's intelligence and ease of use. Furthermore, the use of the mature ESP8266 module and UART communication method ensures communication stability and reliability, reducing the system's development difficulty and cost.

[0065] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A serial communication voice module, characterized in that, It includes a voice input module, a main control module, a voice synthesis module, and a voice amplification circuit. The voice input module includes an analog interface J1, a signal conditioning circuit, a dual-switch interface J2, and an isolation circuit. The analog interface J1 is connected to the first input terminal of the main control module through the signal conditioning circuit, and the dual-switch interface J2 is connected to the second input terminal of the main control module through the isolation circuit. The input terminal of the voice synthesis module is connected to the output terminal of the main control module, and the output terminal of the voice synthesis module is connected to an external speaker B1 through the voice amplification circuit.

2. The serial communication voice module according to claim 1, characterized in that, The signal conditioning circuit includes adjustable resistor R1, resistor R2, Zener diode D1, resistor R3, resistor R4, capacitor C1, amplifier U1, resistor R5, resistor R6, amplifier U2, resistor R7, resistor R8, resistor R9, resistor R10, capacitor C2, diode D2, and diode D3. The first terminal of adjustable resistor R1, the first terminal of resistor R2, and the cathode of Zener diode D1 are all connected to the first pin of analog interface J1. The second terminal of adjustable resistor R1, the second terminal of resistor R2, the anode of Zener diode, the second pin of analog interface J1, and the third pin of analog interface J1 are all grounded. The movable terminal of resistor R1 is connected to the first terminal of resistor R3 and the first terminal of resistor R4. The second terminal of resistor R3 and the first terminal of capacitor C1 are both connected to the non-inverting input of amplifier U1. The second terminal of resistor R4 and the second terminal of capacitor C1 are both grounded. The output terminal of amplifier U1 is connected to the inverting input of amplifier U1 and the first terminal of resistor R5. The second end of resistor R5 is connected to the non-inverting input of amplifier U2 and the first end of resistor R6. The second end of resistor R6 is connected to the power supply. The inverting input of amplifier U2 is grounded through resistor R7. The output of amplifier U2 is connected to the first ends of resistors R8 and R9. The second end of resistor R8 is connected to the inverting input of amplifier U2. The second end of resistor R9 is connected to the first end of resistor R10, the first end of capacitor C2, the cathode of diode D2, the anode of diode D3, and the main control module. The second ends of resistor R10, capacitor C2, and diode D2 are all grounded. The cathode of diode D3 is connected to the power supply.

3. The voice module for serial communication according to claim 1, characterized in that, The isolation circuit includes resistor R11, resistor R12, light-emitting diode LED1, light-emitting diode LED2, resistor R13, diode D4, capacitor C3, field-effect transistor Q1, optocoupler chip U3, resistor R14, and resistor R15. The first end of resistor R11 is connected to the first pin of the dual-switch interface J2. The second end of resistor R11 is connected to the second pin of the dual-switch interface J2, the first end of capacitor C3, the cathode of diode D4, the first end of resistor R13, and the gate of MOSFET Q1. The second end of capacitor C3, the anode of diode D4, the second end of resistor R13, and the source of MOSFET Q1 are all grounded. The first end of resistor R12 is connected to the second pin of the dual-switch interface J2 and the anode of LED1. The second end of resistor R12 is connected to the anode of LED2. The cathodes of LED1 and LED2 are both connected to the third pin of the dual-switch interface J2 and grounded. The drain of MOSFET Q1 is connected to the cathode of the light-emitting terminal of optocoupler chip U3. The anode of the light-emitting terminal of optocoupler chip U3 is connected to the power supply through resistor R14. The collector of the light-receiving terminal of optocoupler chip U3 is connected to the power supply. The emitter of the light-receiving terminal of optocoupler chip U3 is connected to the first end of resistor R15 and the main control module. The second end of resistor R15 is grounded.

4. The serial communication voice module according to claim 3, characterized in that, The optocoupler chip U3 uses the HCPL2201 model.

5. The serial communication voice module according to claim 1, characterized in that, The voice amplifier circuit includes resistor R16, capacitor C4, capacitor C5, resistor R17, resistor R18, capacitor C8, capacitor C6, capacitor C7, resistor R19, operational amplifier U4, capacitor C9, resistor R20, adjustable resistor R21, resistor R22, resistor R23, capacitor C10, inductor L1, and capacitor C11. The first terminals of resistor R16, capacitor C4, and capacitor C5 are all connected to the output of the speech synthesis module. The second terminal of capacitor C4 is grounded. The second terminal of resistor R16 is connected to the power supply. The first terminals of resistor R17, capacitor C6, and capacitor C7 are connected to the power supply. The second terminals of capacitor C6 and capacitor C7 are grounded. The second terminal of resistor R17 is connected to the first terminals of resistor R18 and capacitor C8. The second terminals of resistor R18 and capacitor C8 are both grounded. The second terminal of capacitor C5 is connected to the first pin of operational amplifier U4, the first terminal of capacitor C9, the first terminal of resistor R20, and the adjustable resistor R2 through resistor R19. The first terminal of 1 is connected to the active terminal of the adjustable resistor R21. The second terminal of resistor R20 is connected to the first terminal of resistor R22. The second terminals of capacitor C9, adjustable resistor R21, and resistor R22 are all connected to the second pin of operational amplifier U4. The third pin of operational amplifier U4 is connected to the second terminal of resistor R17 and the first terminal of resistor R23. The second terminal of resistor R23 is connected to the first terminal of capacitor C10 and the first terminal of inductor L1. The second terminal of capacitor C10 is grounded. The second terminal of inductor L1 is connected to the first terminal of capacitor C11 and the first pin of external speaker B1. The second terminal of capacitor C11 and the second pin of external speaker B1 are both grounded.

6. The serial communication voice module according to claim 1, characterized in that, The main control module uses an ESP32-C3 main control chip.

7. The voice module for serial communication according to claim 1, characterized in that, The speech synthesis module uses the SNR9816 speech synthesis chip.

8. The voice module for serial communication according to claim 1, characterized in that, It also includes a WIFI module, through which the main control module connects to an external terminal.

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