CN203407000U - Voice output adjustment circuit and audio and video playing equipment - Google Patents

Abstract

The utility model discloses a sound output adjustment circuit and an audio and video playback device. The sound output adjustment circuit is connected with a main controller of the audio and video playback device, and includes an earphone terminal, a loudspeaker, an audio output end, a signal coupling module, a signal attenuation module and a switch control module. In the sound output adjustment circuit of the present utility model, when the control signal output by the main controller is at a high level, the switch control module cuts off the channel from which the AC sound signal is output to the loudspeaker; when the control signal is at a low level, the switch control module controls the AC sound signal Output to the speaker, so that the AC sound signal can be output to both the headphone terminal and the speaker, so that the headphone terminal is compatible with the headphone function and the AV OUT audio output function at the same time, which solves the problem of standardization of the sound module of the audio and video playback equipment. Compatibility and matching problems are solved, the production and maintenance costs of standardized components are reduced, and it is easy to use.

Description

Sound output adjustment circuit and audio and video playback equipment

technical field

The utility model relates to the technical field of audio and video playback equipment, in particular to a sound output adjustment circuit and audio and video playback equipment.

Background technique

The modularized and componentized production and sales of consumer electronics products is already a reality, which can maximize the division of labor, improve production efficiency, and reduce production costs. Typical products such as personal computers and televisions are no exception, and the promotion of integrated production and sales of modules and components is being accelerated. This requires the classification and development of components of similar functional modules of the product, and integrate them into standardized components, such as power boards, main boards, and various functional small boards in TVs.

Take the motherboard of a TV as an example, it often has several standard sizes, and for each single size, even if the TV chip on the motherboard, that is, the SOC (System on Chip, System on Chip) has powerful functions, it may be due to The size of the mainboard is not enough, and there is no way to arrange enough terminals to realize all the functions of the SOC, which requires finding terminals that can be shared by multiple functions from the limited terminals. Take the sound module of the main board as an example, if a consumer needs the headphone function, it needs to add a headphone terminal on the main board; if a consumer needs the AV OUT audio output function, it needs to add an AV OUT audio output terminal on the main board, but If both the earphone terminal and the AV OUT audio output terminal are increased, the motherboard of the TV set will not have enough space to arrange the earphone terminal and the AV OUT audio output terminal, which will cause inconvenience to use. Therefore, it is a problem to be solved urgently to make the standardized components of the motherboard sound module compatible with the above-mentioned earphone function and the AV OUT audio output function.

Utility model content

The main purpose of the utility model is to propose a sound output adjustment circuit and audio and video playback equipment, aiming to solve the compatibility and matching problems encountered in the realization of standardized components of the sound module of the audio and video playback equipment, and reduce the production and maintenance costs of standardized components.

In order to achieve the above object, the utility model proposes a sound output adjustment circuit, the sound output adjustment circuit is connected with the main controller of the audio and video playback equipment, the sound output adjustment circuit includes an earphone terminal, a loudspeaker, and is used to output the and an audio output terminal of the amplified sound signal, a signal coupling module for filtering out the DC component in the sound signal to output an AC sound signal, a signal attenuation module for attenuating the AC sound signal, and a A switch control module that controls whether the AC sound signal is output to the speaker according to the control signal output by the main controller;

The input end of the signal coupling module is connected to the audio output end, the output end of the signal coupling module is connected to the input end of the signal attenuation module, and the output end of the signal attenuation module is connected to the earphone terminal; The input terminal of the switch control module is connected to the output terminal of the signal coupling module, the output terminal of the switch control module is connected to the speaker, and the control terminal of the switch control module is connected to the control signal of the main controller. output connection.

Preferably, the audio output terminal includes a right channel audio output terminal and a left channel audio output terminal, and the signal coupling module includes a first coupling capacitor and a second coupling capacitor;

The positive pole of the first coupling capacitor is connected to the audio output terminal of the right channel, the negative pole of the first coupling capacitor is connected to the first input terminal of the switch control module, and is connected to the first input terminal of the signal attenuation module. input connection;

The positive pole of the second coupling capacitor is connected to the left channel audio output terminal, the negative pole of the second coupling capacitor is connected to the second input terminal of the switch control module, and is connected to the second input terminal of the signal attenuation module. input connection.

Preferably, the signal attenuation module includes at least two attenuation resistors, one of the attenuation resistors is connected between the negative pole of the first coupling capacitor and the earphone terminal, and the other of the attenuation resistors is connected to the second between the negative pole of the coupling capacitor and the headphone terminal.

Preferably, the signal attenuation module includes a first attenuation resistor, a second attenuation resistor, a third attenuation resistor and a fourth attenuation resistor;

One end of the first attenuation resistor is connected to the negative pole of the first coupling capacitor and connected to the earphone terminal, and the other end of the first attenuation resistor is connected to the earphone terminal via the second attenuation resistor;

One end of the third attenuation resistor is connected to the negative pole of the second coupling capacitor and connected to the earphone terminal, and the other end of the third attenuation resistor is connected to the earphone terminal via the fourth attenuation resistor.

Preferably, the speaker includes a right channel speaker and a left channel speaker, and the switch control module includes a power input terminal, a first MOS tube, a second MOS tube, a third MOS tube, a fourth MOS tube, a first three pole tube and second triode;

The gate of the first MOS transistor is connected to the power supply input terminal, and is connected to the collector of the first triode, and the drain of the first MOS transistor is connected to the negative electrode of the first coupling capacitor , the source of the first MOS transistor is connected to the source of the second MOS transistor; the gate of the second MOS transistor is connected to the power input terminal, and is connected to the collector of the first triode electrode connection, the drain of the second MOS tube is connected to one end of the right channel speaker, and is connected to the earphone terminal, and the other end of the right channel speaker is grounded; the first triode The base is connected to the first input and output port of the main controller, and the emitter of the first triode is grounded;

The gate of the third MOS transistor is connected to the power supply input terminal, and is connected to the collector of the second triode, and the drain of the third MOS transistor is connected to the negative electrode of the second coupling capacitor , the source of the third MOS transistor is connected to the source of the fourth MOS transistor; the gate of the fourth MOS transistor is connected to the power supply input terminal, and is connected to the collector of the second triode electrode connection, the drain of the fourth MOS tube is connected to one end of the left channel speaker, and is connected to the earphone terminal, and the other end of the left channel speaker is grounded; The base is connected to the second input and output port of the main controller, and the emitter of the second triode is grounded.

Preferably, the switch control module further includes a first resistor, a second resistor, a third resistor and a fourth resistor;

One end of the first resistor is connected to the power supply input end, and the other end of the first resistor is respectively connected to the gate of the first MOS transistor and the gate of the second MOS transistor; the second One end of the resistor is connected to the emitter of the first triode, and the other end of the second resistor is grounded;

One end of the third resistor is connected to the power supply input end, and the other end of the third resistor is respectively connected to the gate of the third MOS transistor and the gate of the fourth MOS transistor; One end of the resistor is connected to the emitter of the second triode, and the other end of the fourth resistor is grounded.

Preferably, the sound output adjustment circuit further includes a filter module for filtering high-frequency signals in the sound signal, and the filter module includes a first filter capacitor and a second filter capacitor;

One end of the first filter capacitor is connected to the drain of the second MOS transistor, the other end of the first filter capacitor is grounded; one end of the second filter capacitor is connected to the drain of the fourth MOS transistor , the other end of the second filtering capacitor is grounded.

The utility model also proposes an audio and video playback device. The audio and video playback device includes a main controller and a sound output adjustment circuit. The sound output adjustment circuit is connected with the main controller of the audio and video playback device. The sound output adjustment circuit It includes a headphone terminal, a loudspeaker, an audio output terminal for outputting a pre-processed and amplified sound signal, a signal coupling module for filtering out a DC component in the sound signal and outputting an AC sound signal, and for connecting the A signal attenuation module for attenuating the AC sound signal, and a switch control module for controlling whether the AC sound signal is output to the speaker according to the control signal output by the main controller;

The input end of the signal coupling module is connected to the audio output end, the output end of the signal coupling module is connected to the input end of the signal attenuation module, and the output end of the signal attenuation module is connected to the earphone terminal; The input terminal of the switch control module is connected to the output terminal of the signal coupling module, the output terminal of the switch control module is connected to the speaker, and the control terminal of the switch control module is connected to the control signal of the main controller. output connection.

The sound output adjustment circuit proposed by the utility model filters out the DC component in the sound signal output from the audio output terminal through the signal coupling module, and outputs the AC sound signal, and the AC sound signal is output to the earphone terminal after being attenuated by the signal attenuation module At the same time, the switch control module is used to control whether the AC sound signal is output to the speaker according to the control signal output by the main controller. Only output to the earphone terminal to realize the earphone function; when the control signal is low level, the AC sound signal is output to the speaker through the switch control module, so that the AC sound signal can be output to both the earphone terminal and the speaker to realize the earphone function AV OUT audio output function. Therefore, the headphone terminal is compatible with the headphone function and the AV OUT audio output function at the same time, which solves the compatibility and matching problems encountered in the realization of standardized components of the sound module of audio and video playback equipment, reduces the production and maintenance costs of standardized components, and is easy to use.

Description of drawings

Fig. 1 is the functional block diagram of the preferred embodiment of the utility model sound output adjustment circuit;

FIG. 2 is a schematic diagram of the circuit structure of a preferred embodiment of the sound output adjustment circuit of the present invention.

The realization of the purpose, functional characteristics and advantages of the utility model will be further described in conjunction with the embodiments and with reference to the accompanying drawings.

Detailed ways

The technical solution of the utility model is further described below in conjunction with the accompanying drawings and specific embodiments of the description. It should be understood that the specific embodiments described here are only used to explain the utility model, and are not intended to limit the utility model.

The utility model provides a sound output adjustment circuit.

Referring to FIG. 1 , FIG. 1 is a functional block diagram of a preferred embodiment of the sound output adjustment circuit 10 of the present invention.

In a preferred embodiment of the present utility model, the sound output adjustment circuit 10 is connected with the main controller 20 of the audio and video playback equipment, and the sound output adjustment circuit 10 includes an earphone terminal 11, a loudspeaker 12, an audio output terminal 13, a signal coupling module 14, A signal attenuation module 15 and a switch control module 16 . The audio output terminal 13 is used to output the sound signal processed and amplified by the previous stage, the signal coupling module 14 is used to filter out the DC component in the sound signal to output the AC sound signal, and the signal attenuation module 15 is used to attenuate the AC sound signal, The switch control module 16 is used to control whether the AC sound signal is output to the speaker 12 according to the control signal output by the main controller 20 . In this embodiment, the audio and video playback device may be a TV set or other devices, which is not limited here.

Wherein, the input end of signal coupling module 14 is connected with audio output end 13, the output end of signal coupling module 14 is connected with the input end of signal attenuation module 15, and the output end of signal attenuation module 15 is connected with earphone terminal 11; Switch control module 16 The input end of the switch control module 16 is connected to the output end of the signal coupling module 14, the output end of the switch control module 16 is connected to the speaker 12, and the control end of the switch control module 16 is connected to the control signal output end of the main controller 20.

In this embodiment, the sound signal after pre-processing and amplification is output from the audio output terminal 13 to the signal coupling module 14, and the signal coupling module 14 filters out the DC component in the sound signal, and outputs an AC sound signal. The sound signal is output to the headphone terminal 11 after being attenuated by the signal attenuation module 15 . At the same time, the switch control module 16 controls whether the AC sound signal is output to the speaker 12 according to the control signal output by the main controller 20. In this embodiment, when the main controller 20 detects that the earphone function is in use, the main controller 20 outputs The control signal of the high level is at a high level, and the high level control signal is output to the switch control module 16, which controls the switch control module 16 to turn off, so that the switch control module 16 cuts off the path of the AC sound signal output to the speaker 12, the AC sound The signal can only be output to the earphone terminal 11; when the main controller 20 detects that the AV OUT audio output function is in use, the control signal output by the main controller 20 is low level, and the low level control signal is output to the switch control module 16 , control the switch control module 16 to be turned on, so that the switch control module 16 controls the AC sound signal to be output to the speaker 12 , and the AC sound signal can be output to both the earphone terminal 11 and the speaker 12 .

Equivalent to the prior art, the sound output adjustment circuit 10 of the present invention, when the control signal output by the main controller 20 is at a high level, cuts off the path of the AC sound signal output to the speaker 12 through the switch control module 16, so that the AC sound signal Only output to the earphone terminal 11 to realize the earphone function; when the control signal output by the main controller 20 is at a low level, the AC sound signal is controlled by the switch control module 16 to output to the speaker 12, so that the AC sound signal can be output to the earphone terminal 11 , can be output to loudspeaker 12 again, realizes earphone function AV OUT audio frequency output function. Therefore, the headphone terminal 11 is compatible with the headphone function and the AV OUT audio output function at the same time, which solves the compatibility and matching problems encountered by the sound module of the audio and video playback equipment to realize the standardized components, reduces the production and maintenance costs of the standardized components, and is easy to use .

In this embodiment, the sound output adjustment circuit 10 also includes a filter module 17, the filter module 17 is connected between the switch control module 16 and the speaker 12, when the switch control module 16 is turned on, the AC sound signal output by the switch control module 16 Usually mixed with high-frequency signals, the filter module 17 performs high-frequency filtering processing on the streaming sound signal to filter out the high-frequency signal in the sound signal to remove high-frequency noise, so that after the AC sound signal reaches the speaker 12, the sound from the speaker 12 Clear and noise-free, to achieve a better listening effect.

Referring to FIG. 1 and FIG. 2 together, FIG. 2 is a schematic circuit diagram of a preferred embodiment of the sound output adjustment circuit 10 of the present invention.

In the specific circuit of the present invention shown in FIG. 2 , the audio output terminal 13 includes a right channel audio output terminal SR and a left channel audio output terminal SL, and the signal coupling module 14 includes a first coupling capacitor C1 and a second coupling capacitor C2.

The positive pole of the first coupling capacitor C1 is connected to the right channel audio output terminal SR, the negative pole of the first coupling capacitor C1 is connected to the first input end of the switch control module 16, and is connected to the first input end of the signal attenuation module 15; The anode of the second coupling capacitor C2 is connected to the left channel audio output terminal SL, and the cathode of the second coupling capacitor C2 is connected to the second input end of the switch control module 16 and connected to the second input end of the signal attenuation module 15 .

In this embodiment, the signal attenuation module 15 includes at least two attenuation resistors. One attenuation resistor is connected between the negative pole of the first coupling capacitor C1 and the earphone terminal 11, and the other attenuation resistor is connected between the negative pole of the second coupling capacitor C2 and the earphone terminal. between terminals 11.

Specifically, the signal attenuation module 15 includes a first attenuation resistor R5 , a second attenuation resistor R6 , a third attenuation resistor R7 and a fourth attenuation resistor R8 .

One end of the first attenuation resistor R5 is connected to the negative pole of the first coupling capacitor C1, and is connected to the earphone terminal 11, and the other end of the first attenuation resistor R5 is connected to the earphone terminal 11 via the second attenuation resistor R6; the third attenuation resistor R7 One end is connected to the negative electrode of the second coupling capacitor C2 and connected to the earphone terminal 11 , and the other end of the third attenuating resistor R7 is connected to the earphone terminal 11 via the fourth attenuating resistor R8 .

In this embodiment, by changing the resistance values of the first attenuating resistor R5, the second attenuating resistor R6, the third attenuating resistor R7 and the fourth attenuating resistor R8, the degree of attenuation of the AC sound signal can be changed, so that by properly selecting the first The resistance values of the attenuating resistor R5, the second attenuating resistor R6, the third attenuating resistor R7 and the fourth attenuating resistor R8 make the voltage of the AC sound signal output to the earphone terminal 11 not only meet the voltage required by the earphone function, but also It can meet the voltage required to use the AV OUT audio output function to achieve a better listening effect. For example, the voltage output from the earphone terminal 11 is 0.57～0.9V, and the voltage output from the AV OUT audio output terminal is 0.2～0.8V. Two voltage ranges, the voltage of the AC sound signal attenuated by the first attenuating resistor R5, the second attenuating resistor R6, the third attenuating resistor R7 and the fourth attenuating resistor R8 should be 0.57-0.8V.

In this embodiment, the speaker 12 includes a right-channel speaker R_SPE and a left-channel speaker L_SPE, and the switch control module 16 includes a power input terminal VIN, a first MOS transistor M1, a second MOS transistor M2, a third MOS transistor M3, a fourth MOS transistor MOS transistor M4, the first triode Q1 and the second triode Q2; in this embodiment, the first MOS transistor M1, the second MOS transistor M2, the third MOS transistor M3 and the fourth MOS transistor M4 are all NMOS Since the AC sound signal output to the speaker 12 is an AC signal, and there is a parasitic diode between the drain and the source of the MOS tube, the first MOS tube M1 and the second MOS tube M2 are connected in series, and the third MOS tube M3 and the fourth MOS transistor M4 are connected in series as a switch for controlling the output of the AC sound signal, thereby eliminating the influence of the parasitic diode on the output of the AC sound signal.

Wherein, the gate of the first MOS transistor M1 is connected to the power input terminal VIN, and is connected to the collector of the first triode Q1, and the drain of the first MOS transistor M1 is connected to the negative electrode of the first coupling capacitor C1. The source of the MOS transistor M1 is connected to the source of the second MOS transistor M2; the gate of the second MOS transistor M2 is connected to the power input terminal VIN, and is connected to the collector of the first triode Q1, and the second MOS transistor M2 The drain of the right channel speaker R_SPE is connected to one end of the right channel speaker R_SPE, and is connected to the earphone terminal 11, and the other end of the right channel speaker R_SPE is grounded; the base of the first triode Q1 is connected to the first input and output port of the main controller 20 IO1 is connected, and the emitter of the first triode Q1 is grounded.

The gate of the third MOS transistor M3 is connected to the power input terminal VIN, and is connected to the collector of the second triode Q2, the drain of the third MOS transistor M3 is connected to the negative electrode of the second coupling capacitor C2, and the third MOS transistor M3 The source of M3 is connected to the source of the fourth MOS transistor M4; the gate of the fourth MOS transistor M4 is connected to the power input terminal VIN, and is connected to the collector of the second triode Q2; the drain of the fourth MOS transistor M4 Pole is connected with one end of the left channel speaker L_SPE, and is connected with the earphone terminal 11, and the other end of the left channel speaker L_SPE is grounded; the base of the second triode Q2 is connected with the second input and output port IO2 of the main controller 20 , the emitter of the second transistor Q2 is grounded.

Specifically, the switch control module 16 further includes a first resistor R1 , a second resistor R2 , a third resistor R3 and a fourth resistor R4 .

One end of the first resistor R1 is connected to the power input terminal VIN, and the other end of the first resistor R1 is respectively connected to the gate of the first MOS transistor M1 and the gate of the second MOS transistor M2; one end of the second resistor R2 is connected to the first The emitter of the transistor Q1 is connected, the other end of the second resistor R2 is connected to the ground; one end of the third resistor R3 is connected to the power input terminal VIN, and the other end of the third resistor R3 is respectively connected to the gate of the third MOS transistor M3 and the first The gates of the four MOS transistors M4 are connected; one end of the fourth resistor R4 is connected to the emitter of the second triode Q2, and the other end of the fourth resistor R4 is grounded.

In this embodiment, the filter module 17 includes a first filter capacitor C3 and a second filter capacitor C4.

One end of the first filter capacitor C3 is connected to the drain of the second MOS transistor M2, the other end of the first filter capacitor C3 is grounded; one end of the second filter capacitor C4 is connected to the drain of the fourth MOS transistor M4, and the second filter capacitor The other end of C4 is grounded.

The operating principle of the utility model sound output adjustment circuit 10 is specifically described as follows:

After the sound signal is pre-processed and amplified, the sound signal of the right channel is output from the right channel audio output terminal SR to the positive pole of the first coupling capacitor C1. Since the first coupling capacitor C1 has the function of blocking the output of the DC signal, the second A coupling capacitor C1 can filter out the DC component in the sound signal output from the right channel audio output terminal SR, so that the AC component in the sound signal can be completely output, so that after filtering out the DC component in the sound signal, the first coupling capacitor The sound signal output by C1 is an AC sound signal; similarly, the sound signal of the left channel is output from the left channel audio output terminal SL to the positive pole of the second coupling capacitor C2, and the second coupling capacitor C2 filters out the output signal from the left channel audio output terminal. The DC component in the sound signal output by SL makes the AC component in the sound signal output completely.

The AC sound signal output after the DC component is filtered by the first coupling capacitor C1 is divided into two paths, one path is attenuated by the first attenuation resistor R5 and the second attenuation resistor R6 in the signal attenuation module 15, and the energy of the AC sound signal is appropriately After weakening, the output is sent to the earphone terminal 11, and the other output is sent to the drain of the first MOS transistor M1.

The AC sound signal output after the DC component is filtered by the second coupling capacitor C2 is also divided into two paths, one path is attenuated by the third attenuation resistor R7 and the fourth attenuation resistor R8 in the signal attenuation module 15, and the energy of the AC sound signal After being appropriately weakened, the output is sent to the headphone terminal 11, and the other output is sent to the drain of the third MOS transistor M3.

When the main controller 20 detects that the earphone function is in use, the main controller 20 outputs a high-level control signal to the base of the first triode Q1 through its first input and output port IO1, and the main controller 20 passes through its first input and output port IO1. The second input and output port IO2 outputs a high-level control signal to the base of the second transistor Q2, so that the first transistor Q1 and the second transistor Q2 are turned on. At this time, the gate of the first MOS transistor M1, the gate of the second MOS transistor M2, the gate of the third MOS transistor M3 and the gate of the fourth MOS transistor M4 are equivalent to being connected to the ground through the second resistor R2, that is, the gate of the first MOS transistor M3 is connected to the ground through the second resistor R2. The gate of a MOS transistor M1, the gate of the second MOS transistor M2, the gate of the third MOS transistor M3 and the gate of the fourth MOS transistor M4 are at a low level, so that the first MOS transistor M1, the second MOS transistor M2, the third MOS transistor M3, and the fourth MOS transistor M4 are all cut off, and the AC sound signal output after the DC component is filtered by the first coupling capacitor C1 and the second coupling capacitor C2 cannot be output to the speaker 12, so the AC sound signal is only It can be output to the headphone terminal 11, and the headphone terminal 11 is used as a headphone function at this time.

When the main controller 20 detected that the AV OUT audio output function was in use, the control signal output by the main controller 20 to the base of the first triode Q1 through its first input and output port IO1 was low, and the main The control signal output by the controller 20 to the base of the second transistor Q2 through its second input and output port IO2 is also at low level, so that the first transistor Q1 and the second transistor Q2 are turned off. At this time, the voltage (such as 12V) input from the power input terminal VIN is respectively output to the gate of the first MOS transistor M1 and the gate of the second MOS transistor M2 through the first resistor R1, and is respectively output to the gate of the second MOS transistor M2 through the third resistor R3. The gate of the third MOS transistor M3 and the gate of the fourth MOS transistor M4, the gate of the first MOS transistor M1, the gate of the second MOS transistor M2, the gate of the third MOS transistor M3 and the gate of the fourth MOS transistor M4 The gates are all at high level, so that the first MOS transistor M1, the second MOS transistor M2, the third MOS transistor M3 and the fourth MOS transistor M4 are all turned on, and the AC output after filtering the DC component through the first coupling capacitor C1 The sound signal is filtered by the first filter capacitor C3 to filter out the high-frequency signal in the AC sound signal, remove the high-frequency noise, and output it to the right channel speaker R_SPE, and filter out the DC component by the second coupling capacitor C2 The output AC sound signal is filtered by the second filter capacitor C4 to remove high-frequency noise and then output to the left channel speaker L_SPE, so the AC sound signal can be output to both the headphone terminal 11 and the speaker 12 . At this time, the earphone terminal 11 can realize the AV OUT audio output function.

The utility model also proposes an audio and video playback device, the audio and video playback device includes a sound output adjustment circuit 10 and a main controller 20, and the structure, working principle and beneficial effects of the sound output adjustment circuit 10 refer to the above-mentioned The embodiment will not be repeated here. Wherein, the audio and video playback device may be a TV or other devices, which is not limited here.

The above descriptions are only preferred embodiments of the present utility model, and are not therefore limiting the patent scope of the present utility model. Any equivalent structure or equivalent process transformation made by using the specification of the utility model and the contents of the accompanying drawings may be directly or indirectly used in Other relevant technical fields are all included in the patent protection scope of the present utility model in the same way.

Claims (8)

1. A sound output adjustment circuit, which is connected with the main controller of the audio and video playback equipment, is characterized in that it includes an earphone terminal, a loudspeaker, an audio output end for outputting the sound signal after pre-processing and amplification, for a signal coupling module for outputting an AC sound signal by filtering out the DC component in the sound signal, a signal attenuation module for attenuating the AC sound signal, and a signal attenuation module for controlling the Whether the AC sound signal is output to the switch control module of the speaker; The input end of the signal coupling module is connected to the audio output end, the output end of the signal coupling module is connected to the input end of the signal attenuation module, and the output end of the signal attenuation module is connected to the earphone terminal; The input terminal of the switch control module is connected to the output terminal of the signal coupling module, the output terminal of the switch control module is connected to the speaker, and the control terminal of the switch control module is connected to the control signal of the main controller. output connection. 2. The sound output adjustment circuit according to claim 1, wherein the audio output terminal comprises a right channel audio output terminal and a left channel audio output terminal, and the signal coupling module comprises a first coupling capacitor and a second Two coupling capacitors; The positive pole of the first coupling capacitor is connected to the audio output terminal of the right channel, the negative pole of the first coupling capacitor is connected to the first input terminal of the switch control module, and is connected to the first input terminal of the signal attenuation module. input connection; The positive pole of the second coupling capacitor is connected to the left channel audio output terminal, the negative pole of the second coupling capacitor is connected to the second input terminal of the switch control module, and is connected to the second input terminal of the signal attenuation module. input connection. 3. The sound output adjustment circuit according to claim 2, wherein the signal attenuation module includes at least two attenuation resistors, and one of the attenuation resistors is connected to the negative pole of the first coupling capacitor and the earphone terminal Between, another attenuation resistor is connected between the negative pole of the second coupling capacitor and the earphone terminal. 4. The sound output adjustment circuit according to claim 3, wherein the signal attenuation module comprises a first attenuation resistor, a second attenuation resistor, a third attenuation resistor and a fourth attenuation resistor; One end of the first attenuation resistor is connected to the negative pole of the first coupling capacitor and connected to the earphone terminal, and the other end of the first attenuation resistor is connected to the earphone terminal via the second attenuation resistor; One end of the third attenuation resistor is connected to the negative pole of the second coupling capacitor and connected to the earphone terminal, and the other end of the third attenuation resistor is connected to the earphone terminal via the fourth attenuation resistor. 5. The sound output adjustment circuit according to any one of claims 2 to 4, wherein the loudspeaker includes a right channel speaker and a left channel speaker, and the switch control module includes a power input terminal, a first MOS tube, second MOS tube, third MOS tube, fourth MOS tube, first triode and second triode; The gate of the first MOS transistor is connected to the power supply input terminal, and is connected to the collector of the first triode, and the drain of the first MOS transistor is connected to the negative electrode of the first coupling capacitor , the source of the first MOS transistor is connected to the source of the second MOS transistor; the gate of the second MOS transistor is connected to the power input terminal, and is connected to the collector of the first triode electrode connection, the drain of the second MOS tube is connected to one end of the right channel speaker, and is connected to the earphone terminal, and the other end of the right channel speaker is grounded; the first triode The base is connected to the first input and output port of the main controller, and the emitter of the first triode is grounded; The gate of the third MOS transistor is connected to the power supply input terminal, and is connected to the collector of the second triode, and the drain of the third MOS transistor is connected to the negative electrode of the second coupling capacitor , the source of the third MOS transistor is connected to the source of the fourth MOS transistor; the gate of the fourth MOS transistor is connected to the power supply input terminal, and is connected to the collector of the second triode electrode connection, the drain of the fourth MOS tube is connected to one end of the left channel speaker, and is connected to the earphone terminal, and the other end of the left channel speaker is grounded; The base is connected to the second input and output port of the main controller, and the emitter of the second triode is grounded. 6. The sound output adjustment circuit according to claim 5, wherein the switch control module further comprises a first resistor, a second resistor, a third resistor and a fourth resistor; One end of the first resistor is connected to the power supply input end, and the other end of the first resistor is respectively connected to the gate of the first MOS transistor and the gate of the second MOS transistor; the second One end of the resistor is connected to the emitter of the first triode, and the other end of the second resistor is grounded; One end of the third resistor is connected to the power supply input end, and the other end of the third resistor is respectively connected to the gate of the third MOS transistor and the gate of the fourth MOS transistor; One end of the resistor is connected to the emitter of the second triode, and the other end of the fourth resistor is grounded. 7. The sound output adjustment circuit according to claim 6, characterized in that, the sound output adjustment circuit also includes a filter module for filtering out high-frequency signals in the sound signal, and the filter module includes a first a filter capacitor and a second filter capacitor; One end of the first filter capacitor is connected to the drain of the second MOS transistor, the other end of the first filter capacitor is grounded; one end of the second filter capacitor is connected to the drain of the fourth MOS transistor , the other end of the second filtering capacitor is grounded. 8. An audio and video playback device, comprising a main controller, further comprising the sound output adjustment circuit according to any one of claims 1 to 7.

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