Mini conference host with audio interface

Abstract

The utility model relates to a mini meeting host with audio interface, which comprises a mainboard provided with a power output end, an audio signal input end, an audio signal output end and a control signal output end, and an audio interface board provided with an audio input port, an audio output port, an input audio processing unit, an output audio processing unit and a power supply unit; the power supply unit is connected to the power output end of the mainboard; the audio input port is connected to a sound pickup device to receive a first balanced audio signal; the input audio processing unit is connected to the audio input port and the audio signal input end of the mainboard, receives the first balanced audio signal and outputs a first single-end analog audio signal; the output audio processing unit is connected to the audio output port, the audio signal output end and the control signal output end of the mainboard, receives a second single-end analog audio signal and a control level and outputs a second balanced audio signal to the audio output port; and the audio output port is connected to a sound playing device. The utility model can expand the application scenarios of the meeting host.

Description

Technical Field

[0001] This utility model relates to the field of audio technology, and more specifically, to a mini conference host with an audio interface. Background Technology

[0002] With the widespread adoption of remote collaboration, mini converged meeting hosts have become core equipment for modern smart conferencing. They integrate a processor, operating system, and multiple interfaces, allowing the installation of various cloud conferencing software and connection to monitors, cameras, and microphones via HDMI, USB, and other interfaces, thus enabling convenient and intelligent conferencing. Currently, most mini conferencing hosts use 3.5mm headphone jacks or standard microphone input interfaces, which are consumer-grade audio interfaces. Their anti-interference capabilities are weak, and their signal-to-noise ratio is low, making them unsuitable for direct connection to professional audio equipment such as condenser microphones, mixing consoles, and digital audio processors that require 48V phantom power. This limits their audio input and output quality, making it difficult to meet the demands of professional scenarios with stringent sound quality requirements, such as high-end conference rooms, training classrooms, live streaming and recording, and music collaboration. Furthermore, the relatively large size of professional audio interfaces presents a significant technical challenge in terms of how to rationally arrange them within a compact design while simultaneously mitigating circuit interference. Utility Model Content

[0003] The technical problem to be solved by this utility model is to provide a mini conference host with an audio interface, addressing some of the technical deficiencies of the prior art.

[0004] The technical solution adopted by this utility model to solve its technical problem is: to construct a mini conference host with an audio interface, including: a motherboard with a power output terminal, an audio signal input terminal, an audio signal output terminal and a control signal output terminal, and an audio interface board; The audio interface board includes: an audio input port, an audio output port, an input audio processing unit, an output audio processing unit, and a power supply unit; wherein... The power supply unit is connected to the power supply output terminal of the motherboard and is used to convert the power supply output terminal of the motherboard to supply power to the audio interface board. The audio input port is used to connect to a sound pickup device to receive a first balanced audio signal input by the sound pickup device; The input audio processing unit is connected to the audio input port and the audio signal input terminal of the motherboard, and is used to receive the first balanced audio signal and output a first single-ended analog audio signal to the audio signal input terminal of the motherboard, wherein the motherboard is used to output a second single-ended analog audio signal when receiving the first single-ended analog audio signal; The output audio processing unit is connected to the audio output port and the audio signal output terminal and control signal output terminal of the motherboard, and is used to receive the second single-ended analog audio signal and the control level generated by the motherboard to output the second balanced audio signal to the audio output port; The audio output port is used to connect to a sound playback device to play the second balanced audio signal through the sound playback device.

[0005] In one embodiment of the mini conference host of this utility model, the power supply unit includes a phantom power supply unit; The phantom power unit connects the power output terminal of the motherboard and the audio input port, and is used to power the sound pickup device through the audio input port.

[0006] In one embodiment of the mini conference host of this utility model, the phantom power supply unit includes: a phantom power supply switch, a first power conversion circuit, and a second power conversion circuit; The first power conversion circuit is connected to the power output terminal of the motherboard and the phantom power switch, and is used to supply power to the phantom power switch. The phantom power switch generates an enable level when it is turned on and turns off the enable level when it is turned off. The second power conversion circuit is connected to the power output terminal of the motherboard, the phantom power switch and the audio input port, and is used to supply power to the sound pickup device through the audio input port when the enable level is received.

[0007] In one embodiment of the mini conference host of this utility model, the input audio processing unit includes a first filtering circuit, a second filtering circuit, and a balanced-to-unbalanced circuit; The first end of the first filter circuit is connected to the first end of the audio input port, and the second end of the first filter circuit is connected to the first input end of the balanced-to-unbalanced circuit. The first end of the second filter circuit is connected to the second end of the audio input port, and the second end of the second filter circuit is connected to the first input end of the balanced-to-unbalanced circuit. The output of the balanced-to-unbalanced circuit is connected to the audio signal input of the motherboard.

[0008] In one embodiment of the mini conference host of this utility model, the balanced-to-unbalanced circuit includes a first operational amplifier chip, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, and a fifth capacitor; The first end of the first resistor is connected to the second end of the first filter circuit. The second end of the first resistor is connected to the first non-inverting input of the first operational amplifier chip, the first end of the second resistor, and the first end of the first capacitor. The first inverting input of the first operational amplifier chip is connected to the first output of the first operational amplifier chip and the first end of the third resistor. The second end of the third resistor is connected to the second inverting input of the first operational amplifier chip, the first end of the fourth resistor, and the first end of the second capacitor. The second end of the fourth resistor and the second end of the second capacitor are connected to the second output of the first operational amplifier chip and the first end of the third capacitor. The second end of the third capacitor is connected to the audio signal input of the motherboard. The second end of the second resistor and the second end of the first capacitor are connected to the second end of the second filter circuit, the first end of the fifth resistor and the first end of the fourth capacitor. The second end of the fifth resistor is connected to the second non-inverting input terminal of the first operational amplifier chip, the first end of the sixth resistor and the first end of the fifth capacitor. The second end of the fifth resistor, the second end of the sixth resistor and the second end of the fifth capacitor are grounded. The power supply terminal of the first operational amplifier chip is connected to the power supply unit.

[0009] In one embodiment of the mini conference host of this utility model, the audio input port includes: an XLR interface, a first electrostatic discharge protection circuit, and a second electrostatic discharge protection circuit; The first end of the XLR interface is connected to the first end of the first electrostatic discharge protection circuit, the output end of the phantom power supply unit and the first end of the first filter circuit, and the second end of the first electrostatic discharge protection circuit is grounded. The second end of the XLR interface is connected to the first end of the second electrostatic discharge protection circuit, the output end of the phantom power supply unit, and the first end of the second filter circuit, and the second end of the second electrostatic discharge protection circuit is grounded.

[0010] In one embodiment of the mini conference host of this utility model, the output audio processing unit includes an unbalanced to balanced circuit, a third filter circuit, a fourth filter circuit, a first optocoupler isolation circuit, a second optocoupler isolation circuit, and a switching circuit; The input terminal of the unbalanced to balanced circuit is connected to the audio signal output terminal of the motherboard, the first output terminal of the unbalanced to balanced circuit is connected to the first terminal of the third filter circuit, the second terminal of the third filter circuit is connected to the fourth terminal of the first optocoupler isolation circuit, and the third terminal of the first optocoupler isolation circuit is connected to the first terminal of the audio output port. The second output terminal of the unbalanced to balanced circuit is connected to the first terminal of the fourth filter circuit, the second terminal of the fourth filter circuit is connected to the fourth terminal of the second optocoupler isolation circuit, and the third terminal of the second optocoupler isolation circuit is connected to the second terminal of the audio output port. The first terminal of the first optocoupler isolation single channel and the first terminal of the second optocoupler isolation circuit are connected to the power supply unit. The second terminal of the first optocoupler isolation circuit and the second terminal of the first optocoupler isolation circuit are connected to the first terminal of the switching circuit. The second terminal of the switching circuit is grounded. The control terminal of the switching circuit is connected to the control signal output terminal of the motherboard.

[0011] In one embodiment of the mini conference host of this utility model, the unbalanced to balanced circuit includes a second operational amplifier chip, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a sixth capacitor, a seventh capacitor, and an eighth capacitor. The first end of the sixth capacitor is connected to the audio signal output terminal of the motherboard; the second end of the sixth capacitor is connected to the first end of the seventh resistor; the second end of the seventh resistor is connected to the first end of the eighth resistor and the first non-inverting input terminal of the second operational amplifier chip; the first inverting input terminal of the second operational amplifier chip is connected to the first end of the ninth resistor, the first end of the tenth resistor, and the first end of the seventh capacitor; the second end of the tenth resistor, the second end of the seventh capacitor, and the first output terminal of the second operational amplifier chip are connected to the first end of the third filter circuit and the first end of the eleventh resistor. The second end of the eleventh resistor is connected to the second inverting input terminal of the second operational amplifier chip, the first end of the twelfth resistor, and the first end of the eighth capacitor. The second end of the twelfth resistor, the second end of the eighth capacitor, and the second output terminal of the second operational amplifier chip are connected to the first end of the fourth filter circuit. The second non-inverting input terminal of the second operational amplifier chip, the second terminal of the eighth resistor, and the second terminal of the ninth resistor are grounded; The power supply terminal of the second operational amplifier chip is connected to the power supply unit.

[0012] In one embodiment of the mini conference host of this utility model, the audio output port includes: a TRS interface, a third electrostatic discharge protection circuit, and a fourth electrostatic discharge protection circuit; The first end of the TRS interface is connected to the first end of the third electrostatic discharge protection circuit and the third end of the first optocoupler isolation single channel, and the second end of the third electrostatic discharge protection circuit is grounded. The second end of the TRS interface is connected to the first end of the fourth electrostatic discharge protection circuit and the third end of the second optocoupler isolation single channel, and the second end of the fourth electrostatic discharge protection circuit is grounded.

[0013] In one embodiment of the mini conference host of this utility model, the audio interface board includes a first connector and a second connector; The audio signal input terminal, the audio signal output terminal, and the control signal output terminal of the motherboard are connected to the audio interface board via the first connector; The power output terminal of the motherboard is connected to the audio interface board via the second connector.

[0014] The mini conference host with an audio interface that implements this utility model has the following beneficial effects: it greatly expands the application scenarios of the conference host, enabling it to be applied to various high-end professional fields. Attached Figure Description

[0015] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings: Figure 1 This is a schematic diagram of the structure of an embodiment of a mini conference host with an audio interface according to this utility model; Figure 2 This is a partial circuit diagram of an embodiment of a mini conference host with an audio interface according to this utility model; Figure 3 This is a partial circuit diagram of another embodiment of the mini conference host with an audio interface according to this utility model; Figure 4 This is a partial circuit diagram of another embodiment of a mini conference host with an audio interface according to this utility model; Figure 5 This is a partial circuit diagram of another embodiment of a mini conference host with an audio interface according to this utility model; Figure 6 This is a partial circuit diagram of another embodiment of a mini conference host with an audio interface according to this utility model. Detailed Implementation

[0016] To provide a clearer understanding of the technical features, objectives, and effects of this utility model, the specific embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0017] like Figure 1 The image shows an embodiment of a mini conference host with an audio interface according to this utility model. Figure 1In one embodiment of the present invention, a mini conference host with an audio interface is shown. The conference host includes: a motherboard 100 having a power output terminal, an audio signal input terminal, an audio signal output terminal, and a control signal output terminal, and an audio interface board 200; the audio interface board 200 includes: an audio input port 220, an audio output port 230, an input audio processing unit 240, an output audio processing unit 250, and a power supply unit 210; wherein, the power supply unit 210 is connected to the power output terminal of the motherboard 100 and is used to convert the power output terminal of the motherboard 100 to power the audio interface board 200; the audio input port 220 is used to connect to a sound pickup device to receive a first balanced audio signal input by the sound pickup device; The input audio processing unit 240 is connected to the audio input port 220 and the audio signal input terminal of the motherboard 100. It is used to receive the first balanced audio signal and output the first single-ended analog audio signal to the audio signal input terminal of the motherboard 100. The motherboard 100 is used to output the second single-ended analog audio signal when receiving the first single-ended analog audio signal. The output audio processing unit 250 is connected to the audio output port 230 and the audio signal output terminal and control signal output terminal of the motherboard 100. It is used to receive the second single-ended analog audio signal and the control level generated by the motherboard to output the second balanced audio signal to the audio output port 230. The audio output port 230 is used to connect to a sound playback device to play the second balanced audio signal through the sound playback device.

[0018] Specifically, the conference host includes a motherboard 100 and an audio interface board 200. The motherboard 100 has a power output terminal, an audio signal input terminal, an audio signal output terminal, and a control signal output terminal. The power output terminal of the motherboard 100 provides power, the audio signal input terminal receives analog audio, the audio signal output terminal outputs analog audio, and the control signal output terminal provides control levels. The motherboard 100 provides this power output through a corresponding power supply circuit. The audio processor encodes, decodes, and performs intermediate processing on the received analog audio signal and outputs the corresponding analog audio. The power supply circuit and processor structure in the motherboard can use commonly used circuits or modules, and are not limited here. For example, the processor in the motherboard 100 can be a Core i5 1135G7, which receives analog audio through the motherboard 100's audio signal input terminal, processes it, and outputs the corresponding analog audio through the motherboard 100's audio signal output terminal, and outputs control levels through corresponding circuits. The power supply circuit in the motherboard 100 can be configured to perform voltage conversion as needed to obtain the required voltage output at the power supply output terminal of the motherboard 100.

[0019] In the audio interface board 200, an external device is connected via the audio input port 220 to receive external audio signals. This external device can be a microphone or other sound pickup device. The external audio signal output by the sound pickup device corresponds to a first balanced audio signal. This first balanced signal is processed by the input audio processing unit 240 to obtain a first single-ended analog audio signal, which is then input to the motherboard 100. The motherboard 100 performs encoding and decoding processing on the received analog audio to obtain a second single-ended analog audio signal. This second single-ended analog audio signal is input to the output audio processing unit 250 via the audio signal output terminal of the motherboard 100. The output audio processing unit 250 converts the second single-ended analog audio signal to obtain a second balanced audio signal and inputs it to the audio output port 230. The second balanced audio signal is then input to an external device via the audio output port 230 for audio playback. This external device can be a speaker or other sound playback device.

[0020] In one embodiment, such as Figure 2 As shown, the power supply unit 210 includes a phantom power supply unit; the phantom power supply unit connects the power output terminal of the motherboard 100 and the audio input port 220, and is used to supply power to the sound pickup device through the audio input port 220. Specifically, the power supply unit 210 includes a phantom power supply unit to supply power to the sound pickup device.

[0021] In one embodiment, the phantom power unit includes: a phantom power switch, a first power conversion circuit, and a second power conversion circuit; the first power conversion circuit is connected to the power output terminal of the motherboard 100 and the phantom power switch, and is used to supply power to the phantom power switch, wherein the phantom power switch generates an enable level when it is turned on and turns off the enable level when it is turned off; the second power conversion circuit is connected to the power output terminal of the motherboard 100, the phantom power switch, and the audio input port 220, and is used to supply power to the sound pickup device through the audio input port 220 when the enable level is received.

[0022] Specifically, the phantom power switch is powered by a first power conversion circuit. The phantom power switch can be turned on or off by a trigger action. When the phantom power switch is on, the power supply causes it to generate an enable level. This enable level then drives a second power conversion circuit, which converts the output voltage of the motherboard 100's power supply terminal to provide phantom power to the audio pickup device. When the phantom power switch is off, it disables the enable level output, and the second power conversion circuit stops power conversion, thus stopping the phantom power supply to the audio pickup device. This process allows the conference host to be compatible with various audio pickup devices with different needs, expanding its application scenarios. Based on this embodiment, the independent phantom power switch prevents accidental damage to devices that do not support phantom power, improving system security and reliability.

[0023] In one embodiment, such as Figure 2 As shown, the phantom power switch includes switch SW1 and its peripheral circuitry. (As...) Figure 2 and Figure 3 As shown, the first power conversion circuit may include a power conversion chip U3 and its peripheral circuitry to provide power to the phantom power switch via the power conversion chip. Figure 4 As shown, the second power conversion circuit may include a boost chip U4 and its peripheral circuits, as well as an LDO chip U5 and its peripheral circuits. That is, the boost chip U4 boosts the 5V voltage to obtain the required voltage, such as 48V, and after being regulated by the LDO chip U5, it serves as the output of the phantom power supply unit.

[0024] In one embodiment, such as Figure 5 As shown, the input audio processing unit 240 includes a first filtering circuit 242, a second filtering circuit 243, and a balanced-to-unbalanced circuit 241. The first end of the first filtering circuit 242 is connected to the first end of the audio input port 220, and the second end of the first filtering circuit 242 is connected to the first input end of the balanced-to-unbalanced circuit 241. The first end of the second filtering circuit 243 is connected to the second end of the audio input port 220, and the second end of the second filtering circuit 243 is connected to the first input end of the balanced-to-unbalanced circuit 241. The output end of the balanced-to-unbalanced circuit 241 is connected to the audio signal input end of the motherboard 100.

[0025] Specifically, in the input audio processing unit 240, the first balanced audio signal input to the audio input port 220 is filtered by the first filter circuit 242 and the second filter circuit 243 respectively. The filtered signal is converted by the balanced-to-unbalanced circuit 241 to obtain a single-ended audio signal, which is then input to the audio signal input terminal of the motherboard 100.

[0026] The first filter circuit 242 can be a π-shaped filter, which may include capacitor C4, ferrite bead FB1, capacitor C5, and capacitor C6. The first terminal of capacitor C4 is connected to the first terminal of the audio input interface and the first terminal of ferrite bead FB1, and the second terminal of capacitor C4 is grounded. The second terminal of ferrite bead FB1 is connected to the first terminal of capacitor C5 and the first terminal of capacitor C6, the second terminal of capacitor C5 is grounded, and the second terminal of capacitor C6 serves as the second terminal of the first filter circuit 242, connected to the first input terminal of the balanced-to-unbalanced circuit 241.

[0027] The second filter circuit 243 can be a π-shaped filter, which may include capacitor C8, ferrite bead FB2, capacitor C9, and capacitor C10. The first terminal of capacitor C8 is connected to the second terminal of the audio input interface and the first terminal of ferrite bead FB2, and the second terminal of capacitor C8 is grounded. The second terminal of ferrite bead FB2 is connected to the first terminal of capacitor C9 and the first terminal of capacitor C10, and the second terminal of capacitor C9 is grounded. The second terminal of capacitor C10 serves as the second terminal of the second filter circuit 243 and is connected to the second input terminal of the balanced-to-unbalanced circuit 241.

[0028] Adding a magnetic bead Π-shaped filter circuit to the audio signal path enhances anti-interference capability and ensures the signal-to-noise ratio of the audio signal.

[0029] In one embodiment, the first end of the first resistor is connected to the second end of the first filter circuit 242; the second end of the first resistor is connected to the first non-inverting input of the first operational amplifier chip, the first end of the second resistor, and the first end of the first capacitor; the first inverting input of the first operational amplifier chip is connected to the first output of the first operational amplifier chip and the first end of the third resistor; the second end of the third resistor is connected to the second inverting input of the first operational amplifier chip, the first end of the fourth resistor, and the first end of the second capacitor; the second end of the fourth resistor and the second end of the second capacitor are connected to the second output of the first operational amplifier chip and the first end of the third capacitor; the second end of the third capacitor is connected to the audio signal input of the motherboard 100; the second end of the second resistor and the second end of the first capacitor are connected to the second end of the second filter circuit 243, the first end of the fifth resistor, and the first end of the fourth capacitor; the second end of the fifth resistor is connected to the second non-inverting input of the first operational amplifier chip, the first end of the sixth resistor, and the first end of the fifth capacitor; the second ends of the fifth resistor, the sixth resistor, and the fifth capacitor are grounded; the power supply terminal of the first operational amplifier chip is connected to the power supply unit 210.

[0030] Specifically, the balanced-to-unbalanced circuit 241 is composed of a first operational amplifier chip integrating two sets of operational amplifiers. This operational amplifier chip is powered by a power supply unit 210. In a specific embodiment, the first operational amplifier chip includes operational amplifier chip U1. The second pin of operational amplifier chip U1 (i.e., the first inverting input terminal of the first operational amplifier chip) is connected to the first pin of operational amplifier chip U1 (i.e., the first output terminal of the first operational amplifier chip), and the third pin of operational amplifier chip U1 (i.e., the first non-inverting input terminal of the first operational amplifier chip) is connected to the second terminal of the first filter circuit 242 via resistor R3 (corresponding to the first resistor). Resistor R6 (corresponding to the second resistor) and capacitor C11 (corresponding to the first capacitor) together form a filter circuit connected between the third pin of operational amplifier chip U1 and resistor R7 (corresponding to the fifth resistor). The second terminal of resistor R7 is connected to the fifth pin of operational amplifier chip U1 (i.e., the second non-inverting input terminal of the first operational amplifier chip), and the first pin of operational amplifier chip U1 is also connected to the sixth pin of operational amplifier chip U1 (i.e., the second inverting input terminal of the first operational amplifier chip) via resistor R5 (corresponding to the third resistor). Meanwhile, the sixth pin of operational amplifier chip U1 is connected to the sixth pin of operational amplifier chip U1 (i.e., the second output terminal of the first operational amplifier chip) via resistor R4 (corresponding to the fourth resistor) and capacitor C7 (corresponding to the second capacitor). Finally, the sixth pin of operational amplifier chip U1 outputs the first single-ended analog audio signal and inputs it to the audio signal input terminal of motherboard 100 via capacitor C12 (corresponding to the third capacitor).

[0031] In one embodiment, the audio input port 220 includes: an XLR interface, a first electrostatic discharge (ESD) protection circuit, and a second ESD protection circuit; the first end of the XLR interface is connected to the first end of the first ESD protection circuit, the output end of the phantom power supply unit, and the first end of the first filter circuit 242, and the second end of the first ESD protection circuit is grounded; the second end of the XLR interface is connected to the first end of the second ESD protection circuit, the output end of the phantom power supply unit, and the first end of the second filter circuit 243, and the second end of the second ESD protection circuit is grounded.

[0032] Specifically, in audio input port 220, the XLR interface J1 is used to connect the sound pickup device. The first electrostatic discharge (ESD) protection circuit includes an ESD protection chip ESD1, one end of which is connected to one input pin of the XLR interface J1, and the other end is grounded. The second ESD protection circuit includes an ESD protection chip ESD2, one end of which is connected to the other input pin of the XLR interface J1, and the other end is grounded. The output of the phantom power unit is connected to the two input pins of the XLR interface J1 to supply power to the sound pickup device.

[0033] In one embodiment, such as Figure 6As shown, the output audio processing unit 250 includes an unbalanced to balanced circuit 251, a third filter circuit 252, a fourth filter circuit 253, a first optocoupler isolation circuit 254, a second optocoupler isolation circuit 255, and a switching circuit 256. The input terminal of the unbalanced to balanced circuit 251 is connected to the audio signal output terminal of the motherboard 100, the first output terminal of the unbalanced to balanced circuit 251 is connected to the first terminal of the third filter circuit 252, the second terminal of the third filter circuit 252 is connected to the fourth terminal of the first optocoupler isolation circuit 254, and the third terminal of the first optocoupler isolation circuit 254 is connected to the first terminal of the audio output port 230. The second output terminal of 251 is connected to the first terminal of the fourth filter circuit 253. The second terminal of the fourth filter circuit 253 is connected to the fourth terminal of the second optocoupler isolation circuit 255. The third terminal of the second optocoupler isolation circuit 255 is connected to the second terminal of the audio output port 230. The first terminal of the first optocoupler isolation circuit 254 and the first terminal of the second optocoupler isolation circuit 255 are connected to the power supply unit 210. The second terminals of the first optocoupler isolation circuit 254 and the second terminal of the first optocoupler isolation circuit 254 are connected to the first terminal of the switch circuit 256. The second terminal of the switch circuit 256 is grounded. The control terminal of the switch circuit 256 is connected to the control signal output terminal of the motherboard 100.

[0034] Specifically, the second single-ended analog audio signal output from the audio signal output terminal of the motherboard 100 is converted from an unbalanced to a balanced signal by the unbalanced-to-balanced circuit 251 to output a second balanced audio signal. This second balanced audio signal is then filtered by the third filter circuit 252 and the fourth filter circuit 253, and finally output to the audio output port 230 via the first optocoupler isolation circuit 254 and the second optocoupler isolation circuit 255. The first optocoupler isolation circuit 254 and the second optocoupler isolation circuit 255 are controlled to be turned on or off by the switch circuit 256 to control the audio output. The control terminal of the switch circuit 256 receives a control signal from the control signal output terminal of the motherboard 100 to control the operation of the first optocoupler isolation circuit 254 and the second optocoupler isolation circuit 255.

[0035] The third filter circuit 252 includes capacitor C20, resistor R18, resistor R20, and capacitor C21. The first output terminal of the unbalanced to balanced circuit 251 is connected to the first terminal of resistor R20 and capacitor C21 via cascaded capacitor C20 and resistor R18, and is also connected to the fourth terminal of the first optocoupler isolation circuit 254. The second terminal of resistor R20 and capacitor C21 is grounded. The fourth filter circuit 253 includes capacitor C16, resistor R12, resistor R14, and capacitor C17. The second output terminal of the unbalanced to balanced circuit 251 is connected to the first terminal of resistor R14 and capacitor C17 via cascaded capacitor C16 and resistor R12, and is also connected to the fourth terminal of the second optocoupler isolation circuit 255. The second terminal of resistor R14 and capacitor C17 is grounded.

[0036] The first optocoupler isolation circuit 254 includes an optocoupler chip Q1 and its peripheral circuits, and the second optocoupler isolation circuit 255 includes an optocoupler chip Q2 and its peripheral circuits. Both the first optocoupler isolation circuit 254 and the second optocoupler isolation circuit 255 are powered by the power supply unit 210. In one specific embodiment, the power output from the power supply output terminal of the motherboard 100 can be converted by the aforementioned first power conversion circuit to obtain the required operating voltage to power the first optocoupler isolation circuit 254 and the second optocoupler isolation circuit 255.

[0037] The switching circuit 256 may include a MOSFET Q3 and its peripheral circuitry. The gate of the MOSFET Q3 receives a control level output from the motherboard 100 to control its on / off state, thereby controlling the power supply unit 210 to power on / off the first optocoupler isolation circuit 254 and the second optocoupler isolation circuit 255. This controls the on / off state of the first and second optocoupler isolation circuits 254 and 255, ultimately enabling the audio playback device to play or stop playing the second balanced audio signal. In this embodiment, the optocoupler isolation circuits provide electrical isolation, improving anti-interference capabilities and further ensuring the signal-to-noise ratio of the audio signal.

[0038] In one embodiment, the unbalanced-to-balanced circuit 251 includes a second operational amplifier chip, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a sixth capacitor, a seventh capacitor, and an eighth capacitor; the first terminal of the sixth capacitor is connected to the audio signal output terminal of the motherboard 100, the second terminal of the sixth capacitor is connected to the first terminal of the seventh resistor, the second terminal of the seventh resistor is connected to the first terminal of the eighth resistor and the first non-inverting input terminal of the second operational amplifier chip, the first inverting input terminal of the second operational amplifier chip is connected to the first terminals of the ninth resistor, the tenth resistor, and the seventh capacitor, the second terminal of the tenth resistor, the second terminal of the seventh capacitor, and the first output terminal of the second operational amplifier chip are connected to the first terminal of the third filter circuit 252 and the first terminal of the eleventh resistor; the second terminal of the eleventh resistor is connected to the second inverting input terminal of the second operational amplifier chip, the first terminal of the twelfth resistor, and the first terminal of the eighth capacitor, the second terminal of the twelfth resistor, the second terminal of the eighth capacitor, and the second output terminal of the second operational amplifier chip are connected to the first terminal of the fourth filter circuit 253; the second non-inverting input terminal of the second operational amplifier chip, the second terminal of the eighth resistor, and the second terminal of the ninth resistor are grounded; the power supply terminal of the second operational amplifier chip is connected to the power supply unit 210.

[0039] Specifically, the unbalanced-to-balanced circuit 251 is composed of a second operational amplifier chip integrating two sets of operational amplifiers. This operational amplifier chip is powered by the power supply unit 210. In a specific embodiment, the second operational amplifier chip includes operational amplifier chip U2. The third pin of operational amplifier chip U2 (corresponding to the first non-inverting input terminal of the second operational amplifier chip) is connected to the audio signal output terminal of the motherboard 100 via a cascaded resistor R11 (corresponding to the seventh resistor) and capacitor C15 (corresponding to the sixth capacitor) to receive the audio signal output of the motherboard 100. The second pin of operational amplifier chip U2 (corresponding to the first inverting input terminal of the second operational amplifier chip) is connected to the first terminal of resistor R17 (corresponding to the eleventh resistor) and the first pin of operational amplifier chip U2 (corresponding to the first output terminal of the second operational amplifier chip) via a parallel-connected resistor R16 (corresponding to the tenth resistor) and capacitor C19 (corresponding to the seventh capacitor). The first pin of operational amplifier chip U2 is used to connect to the first terminal of the third filter circuit 252. The second end of resistor R17 is connected to the sixth pin of op-amp chip U2 (corresponding to the second inverting input of the second op-amp chip), and is connected to the first end of the fourth filter circuit 253 via resistor R13 (corresponding to the twelfth resistor) and capacitor C18 (corresponding to the eighth capacitor) connected in parallel.

[0040] In one embodiment, the audio output port 230 includes: a TRS interface, a third electrostatic discharge (ESD) protection circuit, and a fourth ESD protection circuit; the first end of the TRS interface is connected to the first end of the third ESD protection circuit and the third end of the first optocoupler isolation circuit, and the second end of the third ESD protection circuit is grounded; the second end of the TRS interface is connected to the first end of the fourth ESD protection circuit and the third end of the second optocoupler isolation circuit, and the second end of the fourth ESD protection circuit is grounded.

[0041] Specifically, in audio output port 230, the TRS interface J2 is used to connect to a sound playback device. The third electrostatic discharge (ESD) protection circuit includes an ESD protection chip T2 and a resistor R26. One end of the parallel connection between the ESD protection chip T2 and the resistor R26 is connected to one output pin of the TRS interface J2, and the other end is grounded. The fourth ESD protection circuit includes an ESD protection chip T1 and a resistor R23. One end of the parallel connection between the ESD protection chip T1 and the resistor R23 is connected to another output pin of the TRS interface J2, and the other end is grounded.

[0042] With its professional XLR balanced microphone input and 6.35mm TRS balanced audio output, this conference host is compatible with more external devices, thus expanding its application scenarios.

[0043] In one embodiment, such as Figure 2As shown, the audio interface board 200 includes a first connector and a second connector. The audio signal input terminal, audio signal output terminal, and control signal output terminal of the motherboard 100 are connected to the audio interface board 200 through the first connector; the power supply output terminal of the motherboard 100 is connected to the audio interface board 200 through the second connector. Specifically, the motherboard 100 and the audio interface board 200 can transmit audio signals and control signals through the first connector, and transmit power through the second connector. The first connector includes connector P2, and the second connector includes connector P1. The audio interface board 200 is connected to the motherboard 100 via connectors, which optimizes the internal space utilization of the conference host.

[0044] Meanwhile, this invention employs a balanced audio interface and a professional anti-interference design to ensure high fidelity in audio input and output, significantly improving the sound quality for meetings, recordings, and playback. Furthermore, through a modular sub-board design and a sophisticated internal layout, it successfully integrates larger professional interfaces while maintaining the mini size of the main unit, resolving the conflict between integration and size.

[0045] It is understood that the above embodiments only illustrate preferred embodiments of the present utility model, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present utility model patent. It should be noted that for those skilled in the art, the above technical features can be freely combined, and several modifications and improvements can be made without departing from the concept of the present utility model, all of which fall within the protection scope of the present utility model. Therefore, all equivalent transformations and modifications made within the scope of the claims of the present utility model should fall within the coverage of the claims of the present utility model.

Claims

1. A mini conference host with an audio interface, characterized in that, include: The motherboard is equipped with a power output terminal, an audio signal input terminal, an audio signal output terminal and a control signal output terminal, as well as an audio interface board; The audio interface board includes: an audio input port, an audio output port, an input audio processing unit, an output audio processing unit, and a power supply unit; wherein... The power supply unit is connected to the power supply output terminal of the motherboard and is used to convert the power supply output terminal of the motherboard to supply power to the audio interface board. The audio input port is used to connect to a sound pickup device to receive a first balanced audio signal input by the sound pickup device; The input audio processing unit is connected to the audio input port and the audio signal input terminal of the motherboard, and is used to receive the first balanced audio signal and output a first single-ended analog audio signal to the audio signal input terminal of the motherboard, wherein the motherboard is used to output a second single-ended analog audio signal when receiving the first single-ended analog audio signal; The output audio processing unit is connected to the audio output port and the audio signal output terminal and control signal output terminal of the motherboard, and is used to receive the second single-ended analog audio signal and the control level generated by the motherboard to output the second balanced audio signal to the audio output port; The audio output port is used to connect to a sound playback device to play the second balanced audio signal through the sound playback device.

2. The mini conference host according to claim 1, characterized in that, The power supply unit includes a phantom power supply unit; The phantom power unit connects the power output terminal of the motherboard and the audio input port, and is used to power the sound pickup device through the audio input port.

3. The mini conference host according to claim 2, characterized in that, The phantom power supply unit includes: a phantom power supply switch, a first power conversion circuit, and a second power conversion circuit; The first power conversion circuit is connected to the power output terminal of the motherboard and the phantom power switch, and is used to supply power to the phantom power switch. The phantom power switch generates an enable level when it is turned on and turns off the enable level when it is turned off. The second power conversion circuit is connected to the power output terminal of the motherboard, the phantom power switch and the audio input port, and is used to supply power to the sound pickup device through the audio input port when the enable level is received.

4. The mini conference host according to claim 2, characterized in that, The input audio processing unit includes a first filtering circuit, a second filtering circuit, and a balanced-to-unbalanced circuit; The first end of the first filter circuit is connected to the first end of the audio input port, and the second end of the first filter circuit is connected to the first input end of the balanced-to-unbalanced circuit. The first end of the second filter circuit is connected to the second end of the audio input port, and the second end of the second filter circuit is connected to the first input end of the balanced-to-unbalanced circuit. The output of the balanced-to-unbalanced circuit is connected to the audio signal input of the motherboard.

5. The mini conference host according to claim 4, characterized in that, The balanced-to-unbalanced circuit includes a first operational amplifier chip, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, and a fifth capacitor; The first end of the first resistor is connected to the second end of the first filter circuit. The second end of the first resistor is connected to the first non-inverting input of the first operational amplifier chip, the first end of the second resistor, and the first end of the first capacitor. The first inverting input of the first operational amplifier chip is connected to the first output of the first operational amplifier chip and the first end of the third resistor. The second end of the third resistor is connected to the second inverting input of the first operational amplifier chip, the first end of the fourth resistor, and the first end of the second capacitor. The second end of the fourth resistor and the second end of the second capacitor are connected to the second output of the first operational amplifier chip and the first end of the third capacitor. The second end of the third capacitor is connected to the audio signal input of the motherboard. The second end of the second resistor and the second end of the first capacitor are connected to the second end of the second filter circuit, the first end of the fifth resistor and the first end of the fourth capacitor. The second end of the fifth resistor is connected to the second non-inverting input terminal of the first operational amplifier chip, the first end of the sixth resistor and the first end of the fifth capacitor. The second end of the fifth resistor, the second end of the sixth resistor and the second end of the fifth capacitor are grounded. The power supply terminal of the first operational amplifier chip is connected to the power supply unit.

6. The mini conference host according to claim 4, characterized in that, The audio input port includes: an XLR interface, a first electrostatic discharge protection circuit, and a second electrostatic discharge protection circuit; The first end of the XLR interface is connected to the first end of the first electrostatic discharge protection circuit, the output end of the phantom power supply unit and the first end of the first filter circuit, and the second end of the first electrostatic discharge protection circuit is grounded. The second end of the XLR interface is connected to the first end of the second electrostatic discharge protection circuit, the output end of the phantom power supply unit, and the first end of the second filter circuit, and the second end of the second electrostatic discharge protection circuit is grounded.

7. The mini conference host according to claim 1, characterized in that, The output audio processing unit includes an unbalanced to balanced circuit, a third filter circuit, a fourth filter circuit, a first optocoupler isolation circuit, a second optocoupler isolation circuit, and a switching circuit. The input terminal of the unbalanced to balanced circuit is connected to the audio signal output terminal of the motherboard, the first output terminal of the unbalanced to balanced circuit is connected to the first terminal of the third filter circuit, the second terminal of the third filter circuit is connected to the fourth terminal of the first optocoupler isolation circuit, and the third terminal of the first optocoupler isolation circuit is connected to the first terminal of the audio output port. The second output terminal of the unbalanced to balanced circuit is connected to the first terminal of the fourth filter circuit, the second terminal of the fourth filter circuit is connected to the fourth terminal of the second optocoupler isolation circuit, and the third terminal of the second optocoupler isolation circuit is connected to the second terminal of the audio output port. The first terminal of the first optocoupler isolation single channel and the first terminal of the second optocoupler isolation circuit are connected to the power supply unit. The second terminal of the first optocoupler isolation circuit and the second terminal of the first optocoupler isolation circuit are connected to the first terminal of the switching circuit. The second terminal of the switching circuit is grounded. The control terminal of the switching circuit is connected to the control signal output terminal of the motherboard.

8. The mini conference host according to claim 7, characterized in that, The unbalanced-to-balanced circuit includes a second operational amplifier chip, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a sixth capacitor, a seventh capacitor, and an eighth capacitor; The first end of the sixth capacitor is connected to the audio signal output terminal of the motherboard; the second end of the sixth capacitor is connected to the first end of the seventh resistor; the second end of the seventh resistor is connected to the first end of the eighth resistor and the first non-inverting input terminal of the second operational amplifier chip; the first inverting input terminal of the second operational amplifier chip is connected to the first end of the ninth resistor, the first end of the tenth resistor, and the first end of the seventh capacitor; the second end of the tenth resistor, the second end of the seventh capacitor, and the first output terminal of the second operational amplifier chip are connected to the first end of the third filter circuit and the first end of the eleventh resistor. The second end of the eleventh resistor is connected to the second inverting input terminal of the second operational amplifier chip, the first end of the twelfth resistor, and the first end of the eighth capacitor. The second end of the twelfth resistor, the second end of the eighth capacitor, and the second output terminal of the second operational amplifier chip are connected to the first end of the fourth filter circuit. The second non-inverting input terminal of the second operational amplifier chip, the second terminal of the eighth resistor, and the second terminal of the ninth resistor are grounded; The power supply terminal of the second operational amplifier chip is connected to the power supply unit.

9. The mini conference host according to claim 7, characterized in that, The audio output port includes: a TRS interface, a third electrostatic discharge protection circuit, and a fourth electrostatic discharge protection circuit; The first end of the TRS interface is connected to the first end of the third electrostatic discharge protection circuit and the third end of the first optocoupler isolation single channel, and the second end of the third electrostatic discharge protection circuit is grounded. The second end of the TRS interface is connected to the first end of the fourth electrostatic discharge protection circuit and the third end of the second optocoupler isolation single channel, and the second end of the fourth electrostatic discharge protection circuit is grounded.

10. The mini conference host according to claim 1, characterized in that, The audio interface board includes a first connector and a second connector; The audio signal input terminal, the audio signal output terminal, and the control signal output terminal of the motherboard are connected to the audio interface board via the first connector; The power output terminal of the motherboard is connected to the audio interface board via the second connector.

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