CN214098403U - External sound card - Google Patents

Abstract

The utility model provides an external sound card, the application circuit of which comprises a digital circuit and an analog circuit, a level conversion module comprises a first level conversion unit and a second level conversion unit, the digital circuit comprises a first processing module, the analog circuit comprises a second processing module, and a live broadcast equipment interface is connected with the analog circuit; the external sound card also comprises a first isolation module and a second isolation module, the first isolation module is arranged between the second level conversion unit and the power management module, and the second isolation module is arranged between the first processing module and the second processing module, so that the reference ground of the charging loop and the reference ground of the audio signal loop are mutually isolated through the first isolation module and the second isolation module, the situation that the reference ground of the charging loop and the reference ground of the audio signal loop form a loop is avoided, the situation that the reference ground of the sound card audio signal loop generates extra fluctuation and obvious current sound occurs in an audio signal received by a live mobile phone is avoided, and the live effect is ensured.

Description

External sound card

Technical Field

The utility model relates to a sound card technical field, especially an external sound card.

Background

With the popularization of the live broadcast industry, more and more anchor broadcasters select simple live broadcast scenes carried by mobile terminals such as mobile phones and external sound cards to realize live broadcast. In the process of live broadcasting by a main broadcast, the situation that the electric quantity of a mobile phone and an external sound card is insufficient sometimes occurs.

When a multi-port USB charger or a computer is adopted to charge the mobile phone and the external sound card at the same time, obvious noise is generated, and the live broadcast effect is seriously influenced.

SUMMERY OF THE UTILITY MODEL

Based on above-mentioned current situation, the utility model discloses a main aim at provides an external sound card to solve the noise problem of charging that exists among the prior art.

In order to achieve the above object, the utility model adopts the following technical scheme:

an external sound card comprises a charging interface, a power management module, a battery, a level conversion module, an application circuit and a live broadcast equipment interface, wherein the charging interface and the battery are connected with the power management module, the power management module is used for controlling the battery charging process of the external sound card and the power supply process of the application circuit, the level conversion module is used for carrying out level conversion on the current output by the power management module and then transmitting the current to the application circuit,

the application circuit comprises a digital circuit and an analog circuit, the level conversion module comprises a first level conversion unit corresponding to the digital circuit and a second level conversion unit corresponding to the analog circuit, the digital circuit comprises a first processing module, the analog circuit comprises a second processing module, the digital circuit and the analog circuit are communicated through the first processing module and the second processing module, and the live broadcast equipment interface is connected with the analog circuit;

the external sound card further comprises a first isolation module and a second isolation module, wherein the first isolation module is arranged between the second level conversion unit and the power management module, and the second isolation module is arranged between the first processing module and the second processing module.

Preferably, first processing module includes audio processor and controller, the audio processor with the controller is connected, digital circuit still include with scene key, audio key and/or special effect key that the controller is connected, second processing module includes the codec mixer, the codec mixer with on the communication line between the audio processor, the codec mixer with on the communication line between the controller all be provided with the module is kept apart to the second.

Preferably, external sound card still includes headset interface and audio signal input interface, analog circuit still includes first amplifier, second amplifier and audio mixer, first amplifier sets up the audio input end of headset interface with between the encoding and decoding audio mixer, the second amplifier set up at audio signal input interface with between the encoding and decoding audio mixer, two inputs of audio mixer are connected respectively the encoding and decoding audio mixer with the audio input end of live equipment interface, the output of audio mixer is connected the audio output of headset interface.

Preferably, the first isolation module includes a first conversion circuit, a transformer and a second conversion circuit, which are connected in sequence, the first conversion circuit is configured to convert an input direct current into an alternating current and output the alternating current to a primary side of the transformer, and the second conversion circuit is configured to receive an alternating current output by a secondary side of the transformer and convert the alternating current into a direct current to output.

Preferably, the transformer includes more than two common mode inductors, primary windings of the more than two common mode inductors are arranged in parallel, and secondary windings of the more than two common mode inductors are arranged in series.

Preferably, the first conversion circuit comprises a control chip, a PMOS transistor and an NMOS transistor, and the control chip is configured to control on/off of the PMOS transistor and the NMOS transistor to generate a PWM signal wave with a set duty ratio.

Preferably, the second conversion circuit includes a first diode, a second diode, a third diode and a fourth diode, a negative end of the first diode and a positive end of the second diode are connected to one end of the secondary winding of the transformer, a negative end of the third diode and a positive end of the fourth diode are connected to the other end of the secondary winding of the transformer, a positive end of the first diode and a positive end of the third diode are connected to the ground, a negative end of the second diode and a negative end of the fourth diode are connected to the output end, and a third resistor, a fourth capacitor and a fifth capacitor are connected in parallel between the output end and the ground.

Preferably, a charging end and a data transmission end are integrated in the charging interface, the charging end is connected with the power management module, the data transmission end is connected with the application circuit, and a third isolation module is arranged between the data transmission end and the application circuit.

Preferably, the second isolation module comprises a photo coupler; and/or the presence of a gas in the gas,

the third isolation module includes a photocoupler.

Preferably, the sound card further comprises an accompaniment device interface, and the accompaniment device interface is connected with the analog circuit.

The utility model provides an in the external sound card, divide into digital circuit and analog circuit with application circuit, set up first isolation module between the second level conversion unit that corresponds with analog circuit and power management module, set up the second isolation module between the first processing module that communicates between digital circuit and analog circuit and second processing module, so, keep apart the module with the second through first isolation module and the reference ground that the module will charge the return circuit and separate each other with the reference ground in audio signal return circuit, avoid charging the return circuit reference ground and the reference ground in audio signal return circuit form the loop, lead to sound card audio signal return circuit reference ground to appear extra undulant and appear obvious electric current sound in the audio signal that live cell-phone received, guarantee live effect.

Other advantages of the present invention will be described in the detailed description, and those skilled in the art can understand the technical advantages brought by the technical features and technical solutions through the descriptions of the technical features and the technical solutions.

Drawings

Preferred embodiments according to the present invention will be described below with reference to the accompanying drawings. In the figure:

fig. 1 is a schematic view of a scenario in which a live phone, an external sound card, and an accompanying phone are used simultaneously, and a multi-port USB charger is used to charge the live phone and the external sound card simultaneously;

FIG. 2 is a current walk diagram for the scenario of FIG. 1;

fig. 3 is a current trend chart when the direct broadcasting mobile phone, the external sound card and the computer are used simultaneously and the direct broadcasting mobile phone and the external sound card are charged simultaneously by the computer;

fig. 4 is a circuit diagram of an external sound card according to a first embodiment of the present invention;

fig. 5 is a schematic connection diagram of an analog circuit, a digital circuit and each interface in the external sound card according to an embodiment of the present invention;

fig. 6 is a circuit diagram of a dc isolation power module of an external sound card according to an embodiment of the present invention;

fig. 7 is a current walking diagram when the live phone, the external sound card, and the computer are used simultaneously, the computer is used to charge the live phone and the external sound card simultaneously, and audio data is transmitted to the external sound card;

fig. 8 is a circuit diagram of an external sound card according to the second embodiment of the present invention.

In the figure:

1. an external sound card; 2. live broadcasting a mobile phone; 3. an accompaniment mobile phone; 4. a charger;

10. a charging interface; 20. a power management module; 30. a battery; 41. a first level conversion module; 42. A second level shift module; 51. a digital circuit; 511. a first processing module; 5111. a sound effect processor; 5112. a controller; 512. a scene key; 513. a sound effect key; 514. a special effect key; 52. an analog circuit; 521. a second processing module; 5211. an encoding/decoding mixer; 522. a first amplifier; 523. a second amplifier; 524. a sound mixer; 60. a live device interface; 70. an accompaniment device interface; 80. a first isolation module; 81. a first conversion circuit; 82. a transformer; 821. a common mode inductor; 83. a second conversion circuit; 90. a second isolation module; 110. a third isolation module; 120. a headset interface; 130. an audio signal input interface.

Detailed Description

The present invention will be described below based on examples, but the present invention is not limited to only these examples. In the following detailed description of the present invention, certain specific details are set forth in order to avoid obscuring the spirit of the present invention, well-known methods, procedures, flows, and components have not been described in detail.

Further, those of ordinary skill in the art will appreciate that the drawings provided herein are for illustrative purposes and are not necessarily drawn to scale.

Unless the context clearly requires otherwise, throughout the description and the claims, the words "comprise", "comprising", and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is, what is meant is "including, but not limited to".

In the description of the present invention, it is to be understood that the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. In addition, in the description of the present invention, "a plurality" means two or more unless otherwise specified.

For the problem of charging noise of the existing external sound card, the applicant finds that, when a multi-port USB charger charges the external sound card and the live broadcast mobile phone at the same time, as shown in fig. 1 and fig. 2, a solid line is a 5V charging circuit, a dotted line is a charging reference ground, a two-dot chain line is an audio signal, the charging reference ground and the audio signal reference ground form a loop, a large loop is easily subjected to electromagnetic interference, and as the charging current is large, the ground of the charger fluctuates greatly, so that No. 1 ground fluctuates additionally, so that the audio signal received by the live broadcast mobile phone 2 appears obvious current sound, that is, the noise monitored when the external sound card 1 and the mobile phone are charged by using one charger 4 is current sound. The situation is similar when a multi-port USB charger is used for simultaneously charging the external sound card 1 and the accompaniment mobile phone 3. In addition, as shown in fig. 3, the solid line is a 5V charging circuit, the dotted line is a charging reference ground, the two-dot chain line is an audio signal, when the external sound card and the live broadcast mobile phone are charged by using the same computer, the charging reference ground and the original ground network of the system form a loop, the change of the magnetic field in the circuit surrounded by the loop generates a potential difference on the ground network, a difference value Δ V exists between the ground networks of the transmitting end a and the receiving end B of the analog audio loop during charging in fig. 3, the Δ V fluctuation frequency is related to the charger circuit, and the output end of the audio circuit represents continuous noise. In order to solve the problem, the present application provides an external sound card, as shown in fig. 4, the external sound card includes a charging interface 10, a power management module 20, a battery 30, a level conversion module, an application circuit, and a direct broadcast device interface 60, both the charging interface 10 and the battery 30 are connected to the power management module 20, the power management module 20 is used to control a charging process of the battery 30 of the external sound card 1 and a power supply process to the application circuit, for example, the power management module 20 controls a current of the charging interface 10 and/or the battery to be output to the level conversion module, when the external sound card is externally connected with a power supply, the power management module 20 controls a current of the charging interface 10 to be directly output to the level conversion module through the power management module 20, or controls a current of the charging interface 10 and a current of the battery to be output to the level conversion module through the power management module 20 respectively, or controlling the current of the charging interface 10 to enter the battery 30 to charge the battery 30, and controlling the current of the battery 30 to be output to the level conversion module, and when the external sound card is not externally connected with a power supply, the power management module 20 controls the current of the battery 30 to be output to the level conversion module. The level conversion module is used for performing level conversion on the current output by the power management module 20 and then transmitting the current to an application circuit, and the application circuit comprises an audio processing circuit for processing audio, a control circuit for controlling a button and an indicator light, and the like. The level converting module is, for example, a level converting chip, and is configured to convert an input voltage into a voltage required by each of the circuits, where the voltage required by different circuits may be different, for example, 3.3V, 2.5V, 1.8V, 1.2V, and so on, and each voltage is set by the level converting chip separately for voltage conversion.

The live broadcast equipment interface 60 is connected with an application circuit, and audio signals, control signals and the like in the application circuit can be transmitted to live broadcast equipment (such as a live broadcast mobile phone) through the live broadcast equipment interface 60, so that live broadcast is realized.

In order to solve the problem of charging noise, as shown in fig. 4, in the present application, an application circuit is divided into a digital circuit 51 and an analog circuit 52, the digital circuit 51 is configured to process a digital signal, the analog circuit 52 is configured to process an analog signal, the analog circuit 52 is connected to a live device interface 60, the external sound card 1 outputs audio data to a live device through the analog circuit 52 and the live device interface 60, the digital circuit 51 includes a first processing module 511, the analog circuit 52 includes a second processing module 521, and the digital circuit 51 and the analog circuit 52 communicate with each other through the first processing module 511 and the second processing module 521, for example, the digital circuit 51 may transmit data to the second processing module 521 through the first processing module 511 for processing, and the second processing module 521 may also transmit the processed data to the first processing module 511. It is to be understood that, since the digital circuit 51 processes digital signals and the analog circuit 52 processes analog signals, when the first processing module 511 communicates with the second processing module 521, analog-to-digital or digital-to-analog conversion is required, the digital-to-analog conversion module and the analog-to-digital conversion module may be classified as digital circuits or analog circuits, and are generally classified as analog circuits, that is, the digital-to-analog conversion module and the analog-to-digital conversion module are disposed in the second processing module 521.

Correspondingly, the level shift module includes a first level shift unit 41 corresponding to the digital circuit 51 and a second level shift unit 42 corresponding to the analog circuit 52, the first level shift unit 41 is configured to perform level shift on the current output by the power management module 20 and then transmit the current to the digital circuit 51, the second level shift unit 42 is configured to perform level shift on the current output by the power management module 20 and then transmit the current to the analog circuit 52, the first level shift unit 41 and the second level shift unit 42 are, for example, level shift chips, and both the digital circuit 51 and the analog circuit 52 may need input voltages with different sizes, therefore, in the digital circuit 51, each voltage is individually provided with the corresponding first level shifter 41 for voltage conversion, and in the analog circuit 52, each voltage is also individually provided with the corresponding second level shifter 42 for voltage conversion.

The external sound card further comprises a first isolation module 80 and a second isolation module 90, the first isolation module 80 is arranged between the second level conversion unit 42 and the power management module 20, the second isolation module 90 is arranged between the first processing module 511 and the second processing module 521, the first isolation module 80 and the second isolation module 90 are arranged not to affect the charging and the communication between the processing modules, but also to isolate the reference ground of the charging loop and the reference ground of the audio signal loop from each other, so as to avoid the reference ground of the charging loop and the reference ground of the audio signal loop from forming a loop, and to avoid the additional fluctuation of the reference ground of the sound card audio signal loop to cause obvious current sound in the audio signal received by the live phone, thereby ensuring the live effect.

Further, as shown in fig. 4, the external sound card 1 may further include an accompaniment device interface 70, the accompaniment device interface 70 is connected to the analog circuit 52, accompaniment devices such as the accompaniment phone 3 may be connected to the analog circuit 52 through the accompaniment device interface 70, so as to provide accompaniment audio to the analog circuit 52 through the accompaniment device interface 70, and the analog circuit 52 mixes the accompaniment audio and the main broadcast audio and transmits the mixture to the live broadcast devices such as the live broadcast phone 2 through the live broadcast device interface 60. The external sound card 1 and the accompaniment mobile phone 3 can also have the problem of obvious noise when simultaneously charging by using one charger 4, and the external sound card 1 provided by the application can also solve the problem.

The first isolation module 80 can adopt any module capable of achieving an isolation effect, and in a preferred embodiment, as shown in fig. 6, the first isolation module 80 includes a first conversion circuit 81, a transformer 82 and a second conversion circuit 83 connected in sequence, where the first conversion circuit 81 is configured to convert an input direct current into an alternating current and output the alternating current to a primary side of the transformer 82, and the second conversion circuit 83 is configured to receive an alternating current output by a secondary side of the transformer 82 and convert the alternating current into a direct current for output. The first conversion circuit 81 includes a control chip, a PMOS transistor and an NMOS transistor, the control chip is used for controlling on/off of the PMOS transistor and the NMOS transistor to generate a PWM signal wave with a set duty ratio, so as to convert the direct current input to the first conversion circuit 81 into an alternating current in the form of the PWM signal wave, so as to be transmitted to the second conversion circuit 83 through the transformer 82, and the second conversion circuit 83 converts the alternating current transmitted by the transformer 82 into a direct current for the circuit 50 to use. For example, in a specific embodiment, the control chip includes a TON pin, a CLK pin, a GDN pin, a VCC pin, an NMOS pin, and a PMOS pin, wherein the TON pin, the CLK pin, and the VCC pin are all connected to the source of the PMOS transistor through a first line, the PMOS pin is connected to the gate of the PMOS transistor through a second line, the GDN pin is connected to the source of the NMOS transistor through a third line, the NMOS pin is connected to the gate of the NMOS transistor through a fourth line, the drain of the PMOS transistor is connected to the drain of the NMOS transistor through a fifth line, the TON pin is further connected to the positive electrode of the power supply side through a sixth line, the GDN pin is further connected to the negative electrode of the power supply side through a seventh line, a first resistor R1 is disposed between the first line and the second line, a second resistor R2 is disposed between the third line and the fourth line, a first capacitor C1 is connected between the sixth line and the seventh line, one end of the primary winding of the transformer 82 is connected to the fifth line, and a second capacitor C2 is disposed between the other end of the first line, and a third capacitor C3 is arranged between the third line and the third circuit. The first conversion circuit forms a control signal generation circuit, and a PWM signal wave with a set duty ratio is generated by controlling the on-off of the PMOS tube and the NMOS tube through the control chip.

Since the output will have a voltage drop when the circuit load is running, in order to ensure that the output voltage is within the required range, the transformer 82 needs to be set to 1: n, the value of N may be determined according to the specific circuit, and the transformer 82 needs to be customized. Preferably, as shown in fig. 6, the transformer 82 includes a common mode inductor 821 (the number of primary windings of the common mode inductor 821 is equal to the number of secondary windings), two or more common mode inductors 821 are provided, two or more primary windings of the common mode inductor 821 are connected in parallel, and two or more secondary windings of the common mode inductor 821 are connected in series, so that the plurality of common mode inductors 821 are connected in the manner of forming a 1: the N transformers do not need to be specially customized, and the common-mode inductors with proper quantity are selected according to specific circuits to be connected, so that industrial production is facilitated. The number of the common mode inductors 821 is also determined according to the specific circuit, so as to meet the output voltage requirement, for example, in the embodiment shown in fig. 6, the number of the common mode inductors 821 is three, and of course, may be set to 2, 4 or more according to the specific requirement.

Further, the second converting circuit 83 is provided with a load of about 1mA to prevent the no-load output voltage of the circuit from exceeding the input of the subsequent stage, and in the embodiment shown in fig. 6, the load is a third resistor R3 arranged between the output terminal of the second converting circuit 83 and the ground terminal.

As shown in fig. 6, the second conversion circuit 83 includes a first diode D1, a second diode D2, a third diode D3 and a fourth diode D4, a negative terminal of the first diode D1 and a positive terminal of the second diode D2 are connected to one end of the secondary winding of the transformer 82, a negative terminal of the third diode D3 and a positive terminal of the fourth diode D4 are connected to the other end of the secondary winding of the transformer 82, a positive terminal of the first diode D1 and a positive terminal of the third diode D3 are connected to the ground, a negative terminal of the second diode D2 and a negative terminal of the fourth diode D4 are connected to the output terminal, and a fourth capacitor C4 and a fifth capacitor C5 are connected in parallel between the output terminal and the ground. In this way, the alternating current on the secondary winding side is converted into direct current by the first diode D1, the second diode D2, the third diode D3, and the fourth diode D4 and is output.

The number of the second isolation modules 90 is set according to the number of communication lines between the first processing module 511 and the second processing module 521, that is, the second isolation module 90 is set on each communication line between the first processing module 511 and the second processing module 521. For example, in the embodiment shown in fig. 5, the second processing module 521 includes an encoding and decoding mixer 5211, the external sound card 1 further includes a headset interface 120 and an audio signal input interface 130, the analog circuit 52 further includes a first amplifier 522, a second amplifier 523 and a mixer 524, the first amplifier 522 is disposed between an audio input end of the headset interface 120 and the encoding and decoding mixer 5211, the second amplifier 523 is disposed between the audio signal input interface 130 and the encoding and decoding mixer 5211, two input ends of the mixer 524 are respectively connected to the encoding and decoding mixer 5211 and an audio input end of the live device interface 60, an output end of the mixer 524 is connected to an audio output end of the headset interface 120, the audio signal input interface 130 can be an external microphone or an instrument, and the encoding and decoding mixer 5211 is used for inputting an audio signal input from the headset interface 120 and amplified by the first amplifier 522 and an audio signal input interface 130 and amplifying the audio signal amplified by the second amplifier 523 The digital audio mixing device comprises a sound effect processor 5111 and a controller 5112, the sound effect processor 5111 is connected with the controller 5112, the digital circuit 51 further comprises a scene key 512, a sound effect key 513 and/or an effect key 514 which are connected with the controller 5112, when a key is pressed by a main player, the controller 5112 sends a corresponding control signal to the sound effect processor 5111, the sound effect processor 5111 carries out corresponding sound effect processing on the received digital audio mixing signal, sends the processed audio to an encoding and decoding audio mixer 5211, the processed audio is converted into an analog signal by the encoding and decoding audio mixer 5211 and then output to an audio output end of a live broadcast equipment interface 60 to be uploaded to a live broadcast platform through live broadcast equipment and also output to an audio mixer 524, and the audio mixer 524 conveys the audio input by the audio input end of the audio and the live broadcast equipment interface 60 to the earphone interface 120 While the controller 5112 may also send the control signal to the codec mixer 5211 and to the live device via the codec mixer 5211. The scene key 512 includes, for example, a shouting scene key, a comic scene key, and the like, the sound effect key 513 includes, for example, a doll key, a male-to-female sound key, a female-to-male-to-female-to-male key, a tremble key, and the like, and the special effect key 514 includes, for example, a palm key, an ear lighting key, a laughter key, and the like. Since communication lines exist between the codec mixer 5211 and the sound effects processor 5111 and the controller 5112, a second isolation module 90 is disposed on the communication line between the codec mixer 5211 and the sound effects processor 5111 and on the communication line between the codec mixer 5211 and the controller 5112.

The second isolation module 90 can be any module capable of realizing the above-mentioned isolation effect, preferably, the second isolation module 90 includes a photoelectric coupler, and the photoelectric coupler has advantages of small volume, long service life, impact resistance, strong anti-interference capability and the like. Since the photocouplers are used for unidirectional transmission, two photocouplers connected in parallel are required to be arranged on a bidirectional communication line to realize bidirectional signal transmission.

In the above embodiment, the charging interface 10 is an interface that only has a charging function, the audio data transmission is performed through other interfaces, such as a 3.5mm audio interface, a USB interface, and the like, in another embodiment, the charging interface 10 is used for performing data transmission in addition to the charging of the external sound card 1, that is, a charging terminal and a data transmission terminal are integrated in the charging interface 10, the charging terminal is connected with the power management module 20 to charge the external sound card 1 through the charging terminal, and the data transmission terminal is connected with the application circuit 50, so that the data interaction between the external sound card 1 and the external device is realized through the charging interface 10, for example, as shown in fig. 8, the external device is a computer, and the computer can transmit accompaniment audio data to the digital circuit 51 through the data transmission terminal of the charging interface 10. When the computer is used to charge the direct-broadcast mobile phone 2 and the external sound card 1 at the same time, and the computer is used to transmit audio data to the external sound card 1, as shown in fig. 7, the solid line is a 5V charging circuit, the dotted line is a charging reference ground, and the two-dot chain line is an audio signal, in order to isolate the charging reference ground from the original ground grid of the system, the first isolation module 80 is required to be arranged, and the addition of the first isolation module 80 may damage an audio data transmission loop, so as shown in fig. 8, a third isolation module 110 is also required to be arranged between the data transmission end and the digital circuit 51, so that the circuit may not form a ground loop, but may normally transmit the audio signal. The third isolation module 110 may be any structure capable of achieving isolation without affecting data transmission, such as a photocoupler. Of course, it can be understood that, in the case that the charging terminal and the data transmission terminal are integrated in the charging interface 10, the external sound card may also be additionally provided with a 3.5mm audio interface, a USB interface, and other data transmission interfaces.

It will be appreciated by those skilled in the art that the above-described preferred embodiments may be freely combined, superimposed, without conflict.

It will be understood that the above-described embodiments are illustrative only and not restrictive, and that various obvious and equivalent modifications and substitutions may be made in the details described herein by those skilled in the art without departing from the basic principles of the invention.

Claims (10)

1. An external sound card comprises a charging interface, a power management module, a battery, a level conversion module, an application circuit and a live broadcast equipment interface, wherein the charging interface and the battery are connected with the power management module, the power management module is used for controlling the battery charging process of the external sound card and the power supply process of the application circuit, the level conversion module is used for carrying out level conversion on the current output by the power management module and then transmitting the current to the application circuit, and the external sound card is characterized in that,

the application circuit comprises a digital circuit and an analog circuit, the level conversion module comprises a first level conversion unit corresponding to the digital circuit and a second level conversion unit corresponding to the analog circuit, the digital circuit comprises a first processing module, the analog circuit comprises a second processing module, the digital circuit and the analog circuit are communicated through the first processing module and the second processing module, and the live broadcast equipment interface is connected with the analog circuit;

the external sound card further comprises a first isolation module and a second isolation module, wherein the first isolation module is arranged between the second level conversion unit and the power management module, and the second isolation module is arranged between the first processing module and the second processing module.

2. The external sound card of claim 1, wherein the first processing module comprises a sound effect processor and a controller, the sound effect processor is connected with the controller, the digital circuit further comprises a scene key, a sound effect key and/or a special effect key connected with the controller, the second processing module comprises a codec mixer, and the second isolation module is disposed on a communication line between the codec mixer and the sound effect processor and a communication line between the codec mixer and the controller.

3. The external sound card of claim 2, further comprising a headset interface and an audio signal input interface, wherein the analog circuit further comprises a first amplifier, a second amplifier and a mixer, the first amplifier is disposed between the audio input terminal of the headset interface and the codec mixer, the second amplifier is disposed between the audio signal input interface and the codec mixer, two input terminals of the mixer are respectively connected to the codec mixer and the audio input terminal of the live device interface, and an output terminal of the mixer is connected to an audio output terminal of the headset interface.

4. The external sound card according to claim 1, wherein the first isolation module comprises a first conversion circuit, a transformer and a second conversion circuit, which are connected in sequence, the first conversion circuit is configured to convert an input direct current into an alternating current and output the alternating current to a primary side of the transformer, and the second conversion circuit is configured to receive an alternating current output from a secondary side of the transformer and convert the alternating current into a direct current for output.

5. The external sound card of claim 4, wherein the transformer comprises more than two common mode inductors, primary windings of the more than two common mode inductors are connected in parallel, and secondary windings of the more than two common mode inductors are connected in series.

6. The external sound card of claim 4, wherein the first conversion circuit comprises a control chip, a PMOS transistor and an NMOS transistor, and the control chip is configured to control on/off of the PMOS transistor and the NMOS transistor to generate a PWM signal wave with a set duty ratio.

7. The external sound card of claim 4, wherein the second conversion circuit comprises a first diode, a second diode, a third diode and a fourth diode, a negative terminal of the first diode and a positive terminal of the second diode are connected to one end of the secondary winding of the transformer, a negative terminal of the third diode and a positive terminal of the fourth diode are connected to the other end of the secondary winding of the transformer, a positive terminal of the first diode and a positive terminal of the third diode are connected to the ground of the second conversion circuit, a negative terminal of the second diode and a negative terminal of the fourth diode are connected to the output of the second conversion circuit, and a third resistor, a fourth capacitor and a fifth capacitor are connected in parallel between the output of the second conversion circuit and the ground of the second conversion circuit.

8. The external sound card according to any one of claims 1 to 7, wherein a charging terminal and a data transmission terminal are integrated in the charging interface, the charging terminal is connected to the power management module, the data transmission terminal is connected to the application circuit, and a third isolation module is disposed between the data transmission terminal and the application circuit.

9. The external sound card of claim 8, wherein the second isolation module comprises an opto-coupler; and/or the presence of a gas in the gas,

the third isolation module includes a photocoupler.

10. The external sound card of any one of claims 1 to 7, wherein the sound card further comprises an accompaniment device interface, the accompaniment device interface being connected to the analog circuit.

Images