A dual-channel audio control circuit

Abstract

This invention relates to a dual-channel audio control circuit, comprising a dual potentiometer circuit, a left channel driver circuit, a left channel output filter circuit, a right channel driver circuit, a right channel output filter circuit, a left channel speaker, and a right channel speaker. The dual potentiometer circuit receives and adjusts the dual-channel audio signals. The input terminal of the left channel driver circuit is connected to the left output terminal of the dual potentiometer circuit, and the input terminal of the right channel driver circuit is connected to the right output terminal of the dual potentiometer circuit. The left channel output filter circuit is connected between the left channel driver circuit and the left channel speaker, and the right channel output filter circuit is connected between the right channel driver circuit and the right channel speaker. This invention offers significant advantages in elevator voice systems, providing a more natural and immersive listening experience while meeting the requirements for high fidelity, flexible control, and system integration.

Description

Technical Field

[0001] This utility model relates to the field of elevator voice technology, and in particular to a dual-channel audio control circuit. Background Technology

[0002] With the rapid development of modern commercial office buildings, elevators, as core equipment in vertical transportation, have evolved from simple voice announcements to complex audio systems that also play background music. Traditional elevator voice systems often employ a mono design, resulting in thin sound quality and unclear sound field positioning, making it difficult to meet the demands of high-quality background music playback. While existing dual-channel audio control technology is mature in the consumer electronics field, its direct application in the elevator environment faces the following challenges:

[0003] Insufficient synchronization: Ordinary dual potentiometer circuits are prone to left and right channel imbalance during long-distance signal transmission, affecting stereo effect;

[0004] Anti-interference defects: The elevator electrical environment is complex, and the start and stop of the motor can easily introduce pulse noise, which leads to audio signal distortion;

[0005] High reliability requirements: It needs to operate stably for a long time and has overvoltage protection to avoid frequent maintenance.

[0006] Therefore, there is an urgent need for a dual-channel audio control circuit optimized for elevator scenarios, which can enhance anti-interference capabilities and system reliability while ensuring high-fidelity sound quality. Summary of the Invention

[0007] The present invention aims to address the shortcomings of the prior art by providing a dual-channel audio control circuit.

[0008] To achieve the above objectives, this utility model adopts the following technical solution: a dual-channel audio control circuit, comprising a dual potentiometer circuit, a left channel drive circuit, a left channel output filter circuit, a right channel drive circuit, a right channel output filter circuit, a left channel speaker, and a right channel speaker; the dual potentiometer circuit is used to receive and adjust the dual-channel audio signal; the input terminal of the left channel drive circuit is connected to the left output terminal of the dual potentiometer circuit to drive the left channel speaker; the input terminal of the right channel drive circuit is connected to the right output terminal of the dual potentiometer circuit to drive the right channel speaker; the left channel output filter circuit is connected between the left channel drive circuit and the left channel speaker to filter out unwanted frequency components in the left channel audio signal; the right channel output filter circuit is connected between the right channel drive circuit and the right channel speaker to filter out unwanted frequency components in the right channel audio signal.

[0009] Specifically, the two-channel audio signal includes the left channel audio signal and the right channel audio signal, namely DAC_L and DAC_R.

[0010] Specifically, the dual potentiometer circuit includes resistors R1 and R2, and a dual potentiometer. DAC_L is connected to the sliding contact 2 of the dual potentiometer through resistor R1, and the dual potentiometer outputs INN_L. DAC_R is connected to the sliding contact 5 of the dual potentiometer through resistor R2, and the dual potentiometer outputs INN_R. INN_L is connected to the input of the left channel driver circuit, and INN_R is connected to the input of the right channel driver circuit. By adjusting the positions of the sliding contacts 2 and 5 of the dual potentiometer, the output voltages of the left and right channels are controlled synchronously to achieve the volume adjustment function.

[0011] Specifically, the left channel driver circuit includes feedback resistor R4, feedback resistor R5, input resistor R6, filter capacitor C1, bypass capacitor C2, coupling capacitor C3, and left channel audio power amplifier U1; INN_L is connected to the input pin INN of the left channel audio power amplifier U1 via coupling capacitor C3 and input resistor R6; the power supply pin VDD of the left channel audio power amplifier U1 is grounded through filter capacitor C1 and connected to the operating voltage VCC5V; the ground pin GND of the left channel audio power amplifier U1 is grounded; the output pin of the left channel audio power amplifier U1... The VOP pin outputs the positive voltage VOP_L for the left channel, and the VON pin outputs the negative voltage VON_L for the left channel. The positive voltage VOP_L and the negative voltage VON_L for the left channel are output to the left channel output filter circuit. The bypass pin BYPASS of the left channel audio power amplifier U1 is grounded through the bypass capacitor C2. The feedback pin 1 of the left channel audio power amplifier U1 is connected to the power supply VCC5V through the feedback resistor R4, and the feedback pin 2 is grounded through the feedback resistor R5. The feedback resistor R4 and the feedback resistor R5 form a negative feedback network for accurately setting the voltage gain.

[0012] Specifically, the left channel output filter circuit includes an LC1 filter branch, an LC2 filter branch, and a transient voltage suppressor (TVS1). The LC1 filter branch consists of an inductor L1 and a filter capacitor C4, connected between VOP_L and the positive terminal of the left channel speaker. The LC2 filter branch consists of an inductor L2 and a filter capacitor C5, connected between VON_L and the negative terminal of the left channel speaker. The transient voltage suppressor (TVS1) is connected across the positive and negative terminals of the left channel speaker and in parallel with the LC1 and LC2 filter branches to absorb voltage spikes and protect the left channel speaker. The LC1 and LC2 filter branches together form a differential filter network to filter out high-frequency noise. The ground terminals of the filter capacitors C4 and C5 are connected to the system ground (GND).

[0013] Specifically, the right channel driver circuit includes feedback resistor R7, feedback resistor R8, input resistor R9, filter capacitor C6, bypass capacitor C7, coupling capacitor C8, and right channel audio power amplifier U2; INN_R is connected to the input pin INN of the right channel audio power amplifier U1 via coupling capacitor C8 and input resistor R9; the power supply pin VDD of the right channel audio power amplifier U2 is grounded through filter capacitor C6 and connected to the operating voltage VCC5V; the ground pin GND of the right channel audio power amplifier U2 is grounded; the output pin of the right channel audio power amplifier U2... The VOP pin outputs the positive voltage VOP_R for the right channel, and the VON pin outputs the negative voltage VON_R for the right channel. The positive and negative voltages VOP_R are output to the right channel output filter circuit. The bypass pin BYPASS of the right channel audio power amplifier U2 is grounded through the bypass capacitor C7. The feedback pin 1 of the right channel audio power amplifier U2 is connected to the power supply VCC5V through the feedback resistor R7, and the feedback pin 2 is grounded through the feedback resistor R8. The feedback resistor R7 and the feedback resistor R8 form a negative feedback network for precisely setting the voltage gain.

[0014] Specifically, the right channel output filter circuit includes an LC3 filter branch, an LC4 filter branch, and a transient voltage suppressor (TVS2). The LC3 filter branch consists of an inductor L3 and a filter capacitor C9, connected between VOP_R and the positive terminal of the right channel speaker. The LC4 filter branch consists of an inductor L4 and a filter capacitor C10, connected between VON_R and the negative terminal of the right channel speaker. The transient voltage suppressor (TVS2) is connected across the positive and negative terminals of the right channel speaker and in parallel with the LC3 and LC4 filter branches to absorb voltage spikes and protect the right channel speaker. The LC3 and LC4 filter branches together form a differential filter network to filter out high-frequency noise. The ground terminals of the filter capacitors C9 and C10 are connected to the system ground (GND).

[0015] The beneficial effects of this invention are as follows: This invention uses dual potentiometers to synchronously adjust the volume of the left and right channels, ensuring the consistency of the stereo sound field for background music, eliminating sound image shift within the enclosed space of an elevator, and enhancing passenger immersion. This invention employs an LC filter circuit to suppress high-frequency noise, improve audio signal purity, enhance sound quality, and improve anti-interference capabilities. This invention adds a transient voltage suppressor to effectively absorb voltage spikes, preventing speaker damage due to overvoltage, extending speaker lifespan, and improving reliability. This invention simplifies the layout and improves signal amplification accuracy by using symmetrically designed left and right channel drive circuits and feedback networks, reducing distortion. Simultaneously, the use of standardized components and universal audio power amplifier chips facilitates production and maintenance while ensuring long-term stable circuit operation. Attached Figure Description

[0016] Figure 1 This is a block diagram of the main circuit of this utility model;

[0017] Figure 2 This is a circuit diagram of the dual potentiometer circuit of this utility model;

[0018] Figure 3 This is a circuit diagram of the left channel drive circuit of this utility model;

[0019] Figure 4 This is a circuit diagram of the left channel output filter circuit of this utility model;

[0020] Figure 5 This is a circuit diagram of the right channel drive circuit of this utility model.

[0021] Figure 6 This is a circuit diagram of the right channel output filter circuit of this utility model;

[0022] The following will describe in detail the embodiments of this utility model with reference to the accompanying drawings. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0024] like Figure 1 As shown, a dual-channel audio control circuit includes a dual potentiometer circuit, a left channel driver circuit, a left channel output filter circuit, a right channel driver circuit, a right channel output filter circuit, a left channel speaker, and a right channel speaker. The dual potentiometer circuit is used to receive and adjust the dual-channel audio signals, which include a left channel audio signal and a right channel audio signal, namely DAC_L and DAC_R. The input terminal of the left channel driver circuit is connected to the left output terminal of the dual potentiometer circuit to drive the left channel speaker. The input terminal of the right channel driver circuit is connected to the right output terminal of the dual potentiometer circuit to drive the right channel speaker. The left channel output filter circuit is connected between the left channel driver circuit and the left channel speaker to filter out unwanted frequency components in the left channel audio signal. The right channel output filter circuit is connected between the right channel driver circuit and the right channel speaker to filter out unwanted frequency components in the right channel audio signal.

[0025] like Figure 2As shown, the dual potentiometer circuit includes resistors R1 and R2, and a dual potentiometer. DAC_L is connected to the sliding contact 2 of the dual potentiometer through resistor R1, and the dual potentiometer outputs INN_L. DAC_R is connected to the sliding contact 5 of the dual potentiometer through resistor R2, and the dual potentiometer outputs INN_R. INN_L is connected to the input terminal of the left channel driver circuit, and INN_R is connected to the input terminal of the right channel driver circuit. By adjusting the positions of the sliding contacts 2 and 5 of the dual potentiometer, the output voltages of the left and right channels are controlled synchronously to achieve the volume adjustment function.

[0026] Specifically, the dual potentiometer circuit synchronously adjusts the input signal volume of the left and right channels to ensure stereo balance. Smooth volume control is achieved by changing the output signal strength through a sliding contact. The dual-gang structure ensures synchronized volume changes between the left and right channels, avoiding the sound field shift caused by traditional independent potentiometers. Resistor voltage divider adjustment reduces quantization noise that may be introduced by digital volume control. It is compatible with analog audio input and can be directly connected to the output signal of a DAC (digital-to-analog converter).

[0027] like Figure 3 As shown, the left channel driver circuit includes feedback resistor R4, feedback resistor R5, input resistor R6, filter capacitor C1, bypass capacitor C2, coupling capacitor C3, and left channel audio power amplifier U1; INN_L is connected to the input pin INN of the left channel audio power amplifier U1 via coupling capacitor C3 and input resistor R6; the power supply pin VDD of the left channel audio power amplifier U1 is grounded through filter capacitor C1 and connected to the operating voltage VCC5V; the ground pin GND of the left channel audio power amplifier U1 is grounded; the output pin of the left channel audio power amplifier U1... The VOP pin outputs the positive voltage VOP_L for the left channel, and the VON pin outputs the negative voltage VON_L for the left channel. Both the positive and negative voltages VOP_L are output to the left channel output filter circuit. The BYPASS pin of the left channel audio power amplifier U1 is grounded through the bypass capacitor C2. The feedback pin 1 of the left channel audio power amplifier U1 is connected to the power supply VCC5V through the feedback resistor R4, and the feedback pin 2 is grounded through the feedback resistor R5. The feedback resistor R4 and the feedback resistor R5 form a negative feedback network for precisely setting the voltage gain.

[0028] Specifically, the left channel drive circuit amplifies the weak audio signal from the dual potentiometer, providing sufficient driving capability. A negative feedback network (R4, R5) stabilizes the gain and reduces distortion. The amplification factor can be flexibly set using feedback resistors (R4, R5) to adapt to speakers of different sensitivities. Capacitors (C1, C2) effectively suppress power supply noise and improve the signal-to-noise ratio.

[0029] like Figure 4As shown, the left channel output filter circuit includes an LC1 filter branch, an LC2 filter branch, and a transient voltage suppressor (TVS1). The LC1 filter branch consists of an inductor L1 and a filter capacitor C4, connected between VOP_L and the positive terminal of the left channel speaker. The LC2 filter branch consists of an inductor L2 and a filter capacitor C5, connected between VON_L and the negative terminal of the left channel speaker. The transient voltage suppressor (TVS1) is connected across the positive and negative terminals of the left channel speaker and in parallel with the LC1 and LC2 filter branches to absorb voltage spikes and protect the left channel speaker. The LC1 and LC2 filter branches together form a differential filter network to filter out high-frequency noise. The ground terminals of the filter capacitors C4 and C5 are connected to the system ground (GND).

[0030] Specifically, the left channel output filter circuit filters out high-frequency switching noise from the power amplifier output, provides impedance matching, and optimizes the speaker's frequency response. L1 / C4 and L2 / C5 form a second-order low-pass filter with a cutoff frequency that precisely matches the audio bandwidth, suppressing ultra-high frequency interference. The transient voltage suppressor TVS1 effectively absorbs voltage spikes, preventing speaker damage due to overvoltage. Together with the right channel output filter circuit, it forms a symmetrical filter network, maintaining phase consistency between the left and right channels and improving sound field positioning accuracy.

[0031] like Figure 5 As shown, the right channel driver circuit includes feedback resistor R7, feedback resistor R8, input resistor R9, filter capacitor C6, bypass capacitor C7, coupling capacitor C8, and right channel audio power amplifier U2; INN_R is connected to the input pin INN of the right channel audio power amplifier U1 via coupling capacitor C8 and input resistor R9; the power supply pin VDD of the right channel audio power amplifier U2 is grounded through filter capacitor C6 and connected to the operating voltage VCC5V; the ground pin GND of the right channel audio power amplifier U2 is grounded; the output pin of the right channel audio power amplifier U2 is... The VOP pin outputs the positive voltage VOP_R for the right channel, and the VON pin outputs the negative voltage VON_R for the right channel. Both the positive and negative voltages VOP_R are output to the right channel output filter circuit. The BYPASS pin of the right channel audio power amplifier U2 is grounded through the bypass capacitor C7. The feedback pin 1 of the right channel audio power amplifier U2 is connected to the power supply VCC5V through the feedback resistor R7, and the feedback pin 2 is grounded through the feedback resistor R8. The feedback resistor R7 and the feedback resistor R8 form a negative feedback network for precisely setting the voltage gain.

[0032] Specifically, the right channel drive circuit amplifies the weak audio signal from the dual potentiometer, providing sufficient driving capability. A negative feedback network (R7, R8) stabilizes the gain and reduces distortion. The amplification factor can be flexibly set via feedback resistors (R7, R8) to adapt to speakers of different sensitivities. Capacitors (C6, C7) effectively suppress power supply noise and improve the signal-to-noise ratio.

[0033] like Figure 6 As shown, the right channel output filter circuit includes an LC3 filter branch, an LC4 filter branch, and a transient voltage suppressor (TVS2). The LC3 filter branch consists of an inductor L3 and a filter capacitor C9, connected between VOP_R and the positive terminal of the right channel speaker. The LC4 filter branch consists of an inductor L4 and a filter capacitor C10, connected between VON_R and the negative terminal of the right channel speaker. The transient voltage suppressor (TVS2) is connected across the positive and negative terminals of the right channel speaker and in parallel with the LC3 and LC4 filter branches to absorb voltage spikes and protect the right channel speaker. The LC3 and LC4 filter branches together form a differential filter network to filter out high-frequency noise. The ground terminals of the filter capacitors C9 and C10 are connected to the system ground (GND).

[0034] Specifically, the right channel output filter circuit filters out high-frequency switching noise from the power amplifier output, provides impedance matching, and optimizes the speaker's frequency response. L3 / C9 and L4 / C10 form a second-order low-pass filter with a cutoff frequency that precisely matches the audio bandwidth, suppressing ultra-high frequency interference. The transient voltage suppressor TVS2 effectively absorbs voltage spikes, preventing speaker damage due to overvoltage. Together with the left channel output filter circuit, it forms a symmetrical filter network, maintaining phase consistency between the left and right channels and improving sound field positioning accuracy.

[0035] This invention uses dual potentiometers to synchronously adjust the volume of the left and right channels, ensuring consistent stereo sound field for background music, eliminating sound image shift within the enclosed space of an elevator, and enhancing passenger immersion. It employs an LC filter circuit to suppress high-frequency noise, improving audio signal purity, enhancing sound quality, and increasing anti-interference capabilities. A transient voltage suppressor is added to effectively absorb voltage spikes, preventing speaker damage due to overvoltage, extending speaker lifespan, and improving reliability. The symmetrically designed left and right channel drive circuits and feedback network simplify layout, improve signal amplification accuracy, and reduce distortion. Furthermore, the use of standardized components and universal audio power amplifier chips facilitates production and maintenance while ensuring long-term stable circuit operation.

[0036] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0037] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0038] The present invention has been described above with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any improvements made using the inventive concept and technical solution of the present invention, or direct application to other situations without modification, are all within the protection scope of the present invention.

Claims

1. A two-channel audio control circuit, characterized by It includes a dual potentiometer circuit, a left channel driver circuit, a left channel output filter circuit, a right channel driver circuit, a right channel output filter circuit, a left channel speaker, and a right channel speaker. The dual potentiometer circuit is used to receive and adjust the dual-channel audio signal. The input terminal of the left channel driver circuit is connected to the left output terminal of the dual potentiometer circuit to drive the left channel speaker. The input terminal of the right channel driver circuit is connected to the right output terminal of the dual potentiometer circuit to drive the right channel speaker. The left channel output filter circuit is connected between the left channel driver circuit and the left channel speaker to filter out unwanted frequency components in the left channel audio signal. The right channel output filter circuit is connected between the right channel driver circuit and the right channel speaker to filter out unwanted frequency components in the right channel audio signal.

2. A two-channel audio control circuit according to claim 1, characterized in that The two-channel audio signal includes the left channel audio signal and the right channel audio signal, namely DAC_L and DAC_R.

3. A two-channel audio control circuit according to claim 2, characterized in that The dual potentiometer circuit includes resistors R1 and R2, and a dual potentiometer. DAC_L is connected to the sliding contact 2 of the dual potentiometer through resistor R1, and the dual potentiometer outputs INN_L. DAC_R is connected to the sliding contact 5 of the dual potentiometer through resistor R2, and the dual potentiometer outputs INN_R. INN_L is connected to the input of the left channel driver circuit, and INN_R is connected to the input of the right channel driver circuit. By adjusting the positions of the sliding contacts 2 and 5 of the dual potentiometer, the output voltages of the left and right channels are controlled synchronously to achieve the volume adjustment function.

4. A dual-channel audio control circuit according to claim 3, characterized in that, The left channel driver circuit includes feedback resistor R4, feedback resistor R5, input resistor R6, filter capacitor C1, bypass capacitor C2, coupling capacitor C3, and left channel audio power amplifier U1. INN_L is connected to the input pin INN of the left channel audio power amplifier U1 via coupling capacitor C3 and input resistor R6. The power supply pin VDD of the left channel audio power amplifier U1 is grounded through filter capacitor C1 and connected to the operating voltage VCC5V. The ground pin GND of the left channel audio power amplifier U1 is grounded. The output pin V of the left channel audio power amplifier U1... The OP outputs a positive voltage VOP_L for the left channel, and the output pin VON outputs a negative voltage VON_L for the left channel. Both the positive and negative voltages VOP_L are output to the left channel output filter circuit. The bypass pin BYPASS of the left channel audio power amplifier U1 is grounded through the bypass capacitor C2. The feedback pin 1 of the left channel audio power amplifier U1 is connected to the power supply VCC5V through the feedback resistor R4, and the feedback pin 2 is grounded through the feedback resistor R5. The feedback resistor R4 and the feedback resistor R5 form a negative feedback network for precisely setting the voltage gain.

5. A two-channel audio control circuit according to claim 4, characterized in that The left channel output filtering circuit includes an LC1 filter branch, an LC2 filter branch, and a transient voltage suppressor (TVS1). The LC1 filter branch consists of an inductor L1 and a filter capacitor C4, connected between VOP_L and the positive terminal of the left channel speaker. The LC2 filter branch consists of an inductor L2 and a filter capacitor C5, connected between VON_L and the negative terminal of the left channel speaker. The transient voltage suppressor (TVS1) is connected across the positive and negative terminals of the left channel speaker and in parallel with the LC1 and LC2 filter branches to absorb voltage spikes and protect the left channel speaker. The LC1 and LC2 filter branches together form a differential filter network to filter out high-frequency noise. The ground terminals of the filter capacitors C4 and C5 are connected to the system ground (GND).

6. A two-channel audio control circuit according to claim 3, wherein The right channel driver circuit includes feedback resistor R7, feedback resistor R8, input resistor R9, filter capacitor C6, bypass capacitor C7, coupling capacitor C8, and right channel audio power amplifier U2; INN_R is connected to the input pin INN of the right channel audio power amplifier U1 via coupling capacitor C8 and input resistor R9; the power supply pin VDD of the right channel audio power amplifier U2 is grounded through filter capacitor C6 and connected to the operating voltage VCC5V; the ground pin GND of the right channel audio power amplifier U2 is grounded; the output pin V of the right channel audio power amplifier U2 is connected to the input pin VDD. The OP outputs a positive voltage VOP_R for the right channel, and the VON output pin outputs a negative voltage VON_R for the right channel. Both the positive and negative voltages VOP_R are output to the right channel output filter circuit. The bypass pin BYPASS of the right channel audio power amplifier U2 is grounded through the bypass capacitor C7. The feedback pin 1 of the right channel audio power amplifier U2 is connected to the power supply VCC5V through the feedback resistor R7, and the feedback pin 2 is grounded through the feedback resistor R8. The feedback resistor R7 and the feedback resistor R8 form a negative feedback network for precisely setting the voltage gain.

7. A two-channel audio control circuit according to claim 6, characterized in that The right channel output filter circuit includes an LC3 filter branch, an LC4 filter branch, and a transient voltage suppressor (TVS2). The LC3 filter branch consists of an inductor L3 and a filter capacitor C9, connected between VOP_R and the positive terminal of the right channel speaker. The LC4 filter branch consists of an inductor L4 and a filter capacitor C10, connected between VON_R and the negative terminal of the right channel speaker. The transient voltage suppressor (TVS2) is connected across the positive and negative terminals of the right channel speaker and in parallel with the LC3 and LC4 filter branches to absorb voltage spikes and protect the right channel speaker. The LC3 and LC4 filter branches together form a differential filter network to filter out high-frequency noise. The ground terminals of the filter capacitors C9 and C10 are connected to the system ground (GND).

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