Startup and shutdown mute control circuit, audio system and electronic equipment

Abstract

The utility model discloses a switch-on and switch-off mute control circuit, an audio system and an electronic device, the switch-on and switch-off mute control circuit comprises a switch module, the first end of the switch module is electrically connected with the output end of an audio amplification circuit, and the second end of the switch module is grounded. The switch module is used for pulling down the level at the output end of the audio amplification circuit in a conducting state; the first end of the power supply detection module is suitable for receiving a reset level signal, the second end of the power supply detection module is electrically connected with the third end of the switch module, and the power supply detection module is used for controlling the on-off state of the switch module according to the reset level signal. The circuit is simple in design, the POP sound can be eliminated when the audio system is powered on and powered off, and meanwhile the circuit cost and space are saved.

Description

Technical Field

[0001] This utility model relates to the field of audio technology, and in particular to a power-on / off mute control circuit, an audio system, and an electronic device. Background Technology

[0002] In the consumer electronics field, some products have audio amplifier circuits. When the product is powered on and off, the audio amplifier will generate noise signals due to power fluctuations and send them to the speaker, thus producing a pop sound.

[0003] In related technologies, RC circuits are used to eliminate pop noise. However, this RC circuit requires a large capacitor for charging and discharging, which makes the circuit complex, costly, and space-consuming. If the device is turned on quickly, the effect of eliminating pop noise is poor. Utility Model Content

[0004] This invention aims to solve at least one of the technical problems existing in the prior art. Therefore, one objective of this invention is to provide a power-on / off mute control circuit that is simple in design, can eliminate pop-up sounds when the audio system is powered on and off, and simultaneously saves circuit cost and space.

[0005] The second objective of this invention is to provide an audio system.

[0006] The third objective of this utility model is to propose an electronic device.

[0007] To address the aforementioned problems, a first aspect of this utility model provides a power-on / off mute control circuit, comprising: a switch module, wherein a first terminal of the switch module is electrically connected to the output terminal of an audio amplifier circuit, and a second terminal of the switch module is grounded, and the switch module is used to pull down the level at the output terminal of the audio amplifier circuit in a conducting state; and a power supply detection module, wherein a first terminal of the power supply detection module is adapted to receive a reset level signal, and a second terminal of the power supply detection module is electrically connected to a third terminal of the switch module, and the power supply detection module is used to control the switching state of the switch module according to the reset level signal.

[0008] According to the power-on / off mute control circuit of this utility model embodiment, based on the design of the switch module and the power supply detection module, the power supply detection module controls the switching state of the switch module according to the reset level signal during power-on and power-off, thereby eliminating pop-up sounds when the audio system is powered on and off, and saving circuit cost and space.

[0009] In some embodiments, the power supply detection module includes: a power supply unit, a first terminal of which is adapted to be electrically connected to a power supply, and a second terminal of which is grounded; and a switch control unit, a first terminal of which is adapted to receive the reset level signal, a second terminal of which is electrically connected to a third terminal of the power supply unit, a third terminal of which is electrically connected to a third terminal of the switch module, and a fourth terminal of which is grounded. The switch control unit is used to control the switching state of the switch module according to the reset level signal under the power supply of the power supply.

[0010] In some embodiments, the power supply unit includes: a first resistor, a first end of which is adapted to be electrically connected to the power supply, and a second end of which is electrically connected to a second end of the switch control unit; and a second resistor, a first end of which is electrically connected to the second end of the first resistor and the second end of the switch control unit, and a second end of which is grounded.

[0011] In some embodiments, the switch control unit includes: a third resistor, a first terminal of which is adapted to receive the reset level signal; a capacitor, a first terminal of which is electrically connected to a second terminal of the third resistor, and the second terminal of which is grounded; a first transistor, the base of which is electrically connected to the second terminal of the third resistor and the first terminal of the capacitor, the emitter of which is electrically connected to the first terminal of the second resistor and the second terminal of the first resistor, and the collector of which is electrically connected to a third terminal of the switch module; and a fourth resistor, a first terminal of which is electrically connected to the collector of the first transistor and the third terminal of the switch module, and the second terminal of which is grounded.

[0012] In some embodiments, the first transistor is a PNP transistor.

[0013] In some embodiments, the switching module includes: a first switching unit, a first terminal of which is electrically connected to the left channel output terminal of the audio amplifier circuit, a second terminal of which is grounded, and a third terminal of which is electrically connected to the second terminal of the power supply detection module, wherein the first switching unit is used to pull down the level at the left channel output terminal when in a conducting state; and a second switching unit, a first terminal of which is electrically connected to the right channel output terminal of the audio amplifier circuit, a second terminal of which is grounded, and a third terminal of which is electrically connected to the second terminal of the power supply detection module, wherein the second switching unit is used to pull down the level at the right channel output terminal when in a conducting state.

[0014] In some embodiments, the first switching unit or the second switching unit includes: a fifth resistor, the first end of which is electrically connected to the second end of the power supply detection module; a second transistor, the base of which is electrically connected to the second end of the fifth resistor, the collector of which is electrically connected to the left channel output terminal / the right channel output terminal, and the emitter of which is grounded.

[0015] A second aspect of this utility model provides an audio system, including an audio amplifier circuit; and a power-on / mute control circuit as described in the above embodiment, wherein the power-on / mute control circuit is electrically connected to the output terminal of the audio amplifier circuit.

[0016] According to the embodiment of the present invention, the audio system eliminates pop noise when the audio system is powered on and off by setting a power-on mute circuit, thereby saving circuit cost and space.

[0017] In some embodiments, the audio system further includes: an audio control module, wherein a first terminal of the audio control module is adapted to receive an audio control signal, a second terminal of the audio control module is adapted to be connected to a power supply, a third terminal of the audio control module is electrically connected to a preset power supply, a fourth terminal of the audio control module is electrically connected to the third terminal of the switch module in the power-on / off mute control circuit, and a fifth terminal of the audio control module is grounded, and the audio control module is used to control the switching state of the switch module according to the audio control signal.

[0018] A third aspect of this invention provides an electronic device including the audio system described in the above embodiments.

[0019] According to the embodiments of the present invention, the electronic device eliminates pop noise when the audio system is powered on and off, and saves circuit costs and space by setting up an audio system.

[0020] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0021] The above and / or additional aspects and advantages of this utility model will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0022] Figure 1 This is a circuit topology diagram of an audio system according to an embodiment of the present invention;

[0023] Figure 2 This is a structural block diagram of an electronic device according to an embodiment of the present invention.

[0024] Figure label:

[0025] Electronic equipment 2000;

[0026] Audio System 1000;

[0027] Power-on / off mute circuit 100; audio amplifier circuit 200; audio control module 300;

[0028] Switching module 10; Power supply detection module 20;

[0029] Power supply unit 1; switch control unit 2; first switch unit 3; second switch unit 4;

[0030] First resistor R1; second resistor R2; third resistor R3; fourth resistor R5; fifth resistor R5; capacitor C1; first transistor Q1; second transistor Q2. Detailed Implementation

[0031] The embodiments of the present invention are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. The embodiments of the present invention are described in detail below.

[0032] To address the aforementioned problems, the first aspect of this utility model proposes a power-on / off mute control circuit. This circuit is simple in design and can eliminate pop noise when the audio system is powered on and off, while also saving circuit cost and space.

[0033] The following is for reference. Figure 1 The power-on / off mute control circuit 100 according to an embodiment of the present utility model is described as follows: Figure 1 As shown, the power-on / off mute control circuit 100 includes a switch module 10 and a power supply detection module 20.

[0034] The first terminal of the switch module 10 is electrically connected to the output terminal of the audio amplifier circuit, and the second terminal of the switch module 10 is grounded. The switch module 10 is used to pull down the level at the output terminal of the audio amplifier circuit when it is in the on state. The first terminal of the power supply detection module 20 is adapted to receive a reset level signal, and the second terminal of the power supply detection module 20 is electrically connected to the third terminal of the switch module 10. The power supply detection module 20 is used to control the switching state of the switch module 10 according to the reset level signal.

[0035] Specifically, during the power-on and power-off cycles of the product (i.e., the moment the audio system powers on and off), the audio amplifier circuit sends noise signals generated by power supply jitter to the speaker, resulting in pop-up sounds. This application utilizes the unique physical characteristics of the reset level signal during power-on and power-off. By receiving the reset level signal through a power supply detection module, the power supply status is detected to confirm whether the audio amplifier circuit is at the moment of power-on and power-off. Based on the reset level signal, the switching state of the switching module is controlled. When it is confirmed that the audio circuit may output pop-up sounds, the switching module is turned on, pulling down the level of the audio amplifier circuit output terminal, so that the audio amplifier circuit output terminal is directly grounded. This outputs a mute signal at the moment of power-on and power-off of the audio system, eliminating pop-up sounds, while saving circuit cost and space.

[0036] According to the embodiment of the present utility model, the power-on mute control circuit 100 is based on the design of the switch module 10 and the power supply detection module 20. It utilizes the unique physical characteristics of the reset level signal during power-on and power-off. The power supply detection module 20 controls the switching state of the switch module 10 according to the reset level signal, thereby eliminating pop-up sounds when the audio system is powered on and off, and saving circuit cost and space.

[0037] In some embodiments, such as Figure 1 As shown, the power supply detection module 20 includes a power supply unit 1 and a switch control unit 2.

[0038] The first end of the power supply unit 1 is adapted to be electrically connected to the power supply, and the second end of the power supply is grounded; the first end of the switch control unit 2 is adapted to receive a reset level signal, the second end of the switch control unit 2 is electrically connected to the third end of the power supply unit 1, the third end of the switch control unit 2 is electrically connected to the third end of the switch module 10, and the fourth end of the switch control unit 2 is grounded. The switch control unit 2 is used to control the switching state of the switch module 10 according to the reset level signal under the power supply.

[0039] Specifically, when the power supply starts, the power supply unit 1 divides the voltage to supply power to the switch control unit 2. The voltage of the power supply is denoted as VCC. When the power supply starts and stops, the switch control unit 2 receives a reset level signal, i.e., RESET_n signal. The switch control unit 2 can determine the power supply status of the audio system based on this signal and control the switching state of the switch module 10 according to the power supply status of the audio system. Specifically, the reset level signal will remain unchanged at the same level at the moment of power-on until the power-on is completed. Based on this characteristic, after receiving the reset level signal, the switch control unit 2 determines that the power supply status of the audio system is that the audio system may output pop sound at the moment of power-on. In order to avoid the output of pop sound affecting the user experience, this application controls the switch module 10 to conduct through the switch control unit 2, so that the output terminal of the audio amplifier circuit is directly grounded, pulling down the level of the output terminal of the audio amplifier circuit. At this time, the audio amplifier circuit outputs a mute signal, and the audio system has no audio output, thereby realizing instantaneous mute of the audio system when power-on and power-off to eliminate pop sound. Similarly, the principle of noise reduction at the moment of power-off is the same as that of noise reduction at the moment of power-on, and will not be elaborated on here.

[0040] For example, at the moment the power supply starts, the switch control unit 2 receives a low-level reset signal and controls the switch module 10 to turn on. The output terminal of the audio amplifier circuit is directly grounded, meaning the output level is pulled low, and the audio system has no audio output. Subsequently, the audio system begins to reset until the reset is complete. The reset signal remains low, and the switch module 10 remains on. During this process, the audio system has no audio output. After the audio system reset is complete, to ensure that the audio system can work normally, the switch control unit 2 receives the reset signal and changes it from low to high, controlling the switch module 10 to turn off. The output terminal of the audio amplifier circuit is no longer grounded, and the audio system can output audio normally. At the moment the power supply stops, the switch control unit 2 receives the reset signal and changes it from high to low, controlling the switch module 10 to turn on. The output terminal of the audio amplifier circuit is directly grounded, meaning the output level is pulled low, and the audio system has no audio output. Thus, during the power-on and power-off processes of the audio system, the switch module 10 controls the audio amplifier circuit to directly ground, meaning the output level is pulled low, and the audio amplifier circuit outputs a mute signal, eliminating the pop sound. In some embodiments, such as Figure 1 As shown, the power supply unit 1 includes a first resistor R1 and a second resistor R2.

[0041] The first end of the first resistor R1 is electrically connected to the power supply, and the second end of the first resistor R1 is electrically connected to the second end of the switch control unit 2; the first end of the second resistor R2 is electrically connected to the second end of the first resistor R1 and the second end of the switch control unit 2, and the second end of the second resistor R2 is grounded.

[0042] Specifically, after the power supply starts, the power supply unit 1 supplies power to the switch control unit 2 by voltage division through the first resistor R1 and the second resistor R2. When the power supply stops, the supply voltage of the switch control unit 2 decreases. By adjusting the resistance values ​​of the first resistor R1 and the second resistor R2, the voltage after voltage division is controlled, so that the switch control unit 2 can receive a stable operating voltage. Taking a power supply voltage of 12V as an example, when the power supply is on, it provides 3.3V to the switch control unit 2 after voltage division through the first resistor R1 and the second resistor R2. When the audio system is powered off, the voltage received by the switch control unit 2 will drop. If the voltage received by the switch control unit 2 drops to 2.93V, the reset level signal received by the switch control unit 2 will change from a high level signal to a low level signal. At this time, the switch control unit 2 controls the switch module 10 to turn on, and the output terminal of the audio amplifier circuit is directly grounded, that is, the output terminal level is pulled low, and the audio system has no audio output. The supply voltage of the switch control unit 2 can be set according to the actual situation, and no specific limitation is made here.

[0043] In some embodiments, such as Figure 1 As shown, the switch control unit 2 includes a third resistor R3, a capacitor C1, a first transistor Q1, and a fourth resistor R4.

[0044] The first terminal of the third resistor R3 is adapted to receive a reset level signal; the first terminal of the capacitor C1 is electrically connected to the second terminal of the third resistor R3, and the second terminal of the capacitor C1 is grounded; the base of the first transistor Q1 is electrically connected to the second terminal of the third resistor R3 and the first terminal of the capacitor C1; the emitter of the first transistor Q1 is electrically connected to the first terminal of the second resistor R2 and the second terminal of the first resistor R1; the collector of the first transistor Q1 is electrically connected to the third terminal of the switch module 10; the first terminal of the fourth resistor R4 is connected to the collector of the first transistor Q1 and the third terminal of the switch module 10; and the second terminal of the fourth resistor R4 is grounded.

[0045] Specifically, at the instant the power supply is turned on, the reset level signal is low, the first transistor Q1 is turned on, and the base of the first transistor Q1 is grounded through capacitor C1 and the third resistor R3. At this time, the base of the first transistor Q1 is at a low level, and the first transistor Q1 outputs a high level to control the switching module 10 to turn on. The output terminal of the audio amplifier circuit is directly grounded, which pulls down the level of the audio amplifier circuit output. The audio amplifier circuit outputs a mute signal to mute the audio system. After the power supply is turned on, the audio system begins to reset. During the reset, the reset level signal remains low, the first transistor Q1 remains turned on and continues to output a high level to control the switching module 10 to turn on. During this process, the output terminal of the audio amplifier circuit remains grounded and continuously outputs the mute signal. The audio system has no audio output until the audio system reset is complete. To ensure the normal operation of the audio system, the reset level signal changes from low to high. To prevent the audio system from outputting pop sounds, a third resistor R3 and capacitor C1 are used to delay the conduction of the first transistor Q1. After capacitor C1 is fully charged, the first transistor Q1 is turned off, and the switch module 10 is turned off, allowing the audio system to output audio normally. When the power supply stops, the supply voltage of the switch control unit 2 decreases, and the reset IC operates. For example, if the voltage received by the switch control unit drops from 3.3V to 2.93V, the reset level signal changes from a high level to a low level, the first transistor Q1 conducts, and outputs a high level to control the switch module 10 to conduct. The output terminal of the audio amplifier circuit is directly grounded, meaning the output level is pulled low, and the audio amplifier circuit outputs a mute signal. The audio system has no audio output, thus achieving mute. Based on this, the switch control unit 2 controls the switching state of the switch module 10 according to the reset control signal to achieve mute during the power-on and power-off processes of the audio system, eliminating pop sounds. The delay time can be calculated according to Formula 1, where R3 is the resistance value of the third resistor, T is the delay duration, and C1 is the capacitance value.

[0046]

[0047] In some embodiments, the first transistor Q1 is a PNP transistor.

[0048] In addition, it should be noted that the above refers to... Figure 1 The specific circuit connection design of the power supply detection module shown is only one example. Any other modified circuit structures based on this circuit structure that can achieve the detection and control principle of the power supply detection module are also within the scope of protection of this application. For example, the switch control unit can also use other devices besides transistors to implement the switch control function. For example, a MOSFET can be used instead of a PNP transistor, or an NPN transistor can be used, etc., without limitation.

[0049] In some embodiments, such as Figure 1 As shown, the switch module 10 includes a first switch unit 3 and a second switch unit 4.

[0050] The first terminal of the first switching unit 3 is electrically connected to the left channel output terminal of the audio amplifier circuit, the second terminal of the first switching unit 3 is grounded, and the third terminal of the first switching unit 3 is electrically connected to the second terminal of the power supply detection module 20. The first switching unit 3 is used to pull down the level at the left channel output terminal when it is in the conducting state. The first terminal of the second switching unit 4 is electrically connected to the right channel output terminal of the audio amplifier circuit, the second terminal of the second switching unit 4 is grounded, and the third terminal of the second switching unit 4 is electrically connected to the second terminal of the power supply detection module 20. The second switching unit 4 is used to pull down the level at the right channel output terminal when it is in the conducting state.

[0051] Specifically, when the switch module 10 is off, the first switch unit 3 and the second switch unit 4 are in the open state, and the left channel output terminal AR_OUT and the right channel output terminal AL_OUT of the audio system work normally; when the switch module 10 is on, the first switch unit 3 and the second switch unit 4 are in the closed state, and the levels at the left channel output terminal AR_OUT and the right channel output terminal AL_OUT of the audio system are pulled low, and the left channel output terminal AR_OUT and the right channel output terminal AL_OUT are directly grounded, thereby achieving mute of the audio system and eliminating pop sounds.

[0052] In some embodiments, such as Figure 1 As shown, the first switching unit 3 or the second switching unit 4 includes a fifth resistor R5 and a second transistor Q2.

[0053] Among them, the first end of the fifth resistor R5 is electrically connected to the second end of the power supply detection module 20; the base of the second transistor Q2 is electrically connected to the second end of the fifth resistor R5; the collector of the second transistor Q2 is electrically connected to the left channel output terminal AR_OUT / right channel output terminal AL_OUT; and the emitter of the second transistor Q2 is grounded.

[0054] Specifically, taking the first switch unit 3 as an example, when the first switch unit 3 is in the open state, the second transistor Q2 is cut off; when the first switch unit 3 is in the closed state, the second transistor Q2 is turned on, so the left channel output terminal AR_OUT is directly grounded, the level at the left channel output terminal AR_OUT is pulled up, and the left channel output terminal is muted. The control method of the second switch unit 4 is the same as that of the first switch unit 3, and will not be described in detail here.

[0055] A second aspect of this utility model provides an audio system 1000, with reference to... Figure 1 and Figure 2As shown, the audio system 1000 includes an audio amplifier circuit 200 and a power-on / power-off mute control circuit 100.

[0056] The power-on / off mute control circuit 100 is electrically connected to the output terminal of the audio amplifier circuit 200.

[0057] According to the embodiment of the present invention, the audio system 1000 eliminates pop noise when the audio system 1000 is powered on and off by setting a power-on mute circuit 100, thereby saving circuit cost and space.

[0058] In some embodiments, reference Figure 1 and Figure 2 As shown, the audio system also includes an audio control module 300.

[0059] The audio control module 300 has a first terminal adapted to receive audio control signals, a second terminal adapted to connect to a power supply, a third terminal electrically connected to a preset power supply, a fourth terminal electrically connected to the third terminal of the switch module 10 in the power-on / off mute control circuit 100, and a fifth terminal grounded. The audio control module 300 is used to control the switching state of the switch module 10 according to the audio control signals.

[0060] Specifically, when the audio system 1000 is operating normally, the RESET_n signal is always high, and the first transistor Q1 is cut off. Therefore, the switching module 10 is completely controlled by the audio control module 300. That is, the audio control module 300 controls the switching state of the switching module 10 through the audio control signal, i.e., MCU GPIO_1, so that the user can control the audio output of the audio system 1000. The audio control module 300 and the power supply detection module 20 each operate independently to control the audio amplifier circuit.

[0061] The preset power supply voltage is denoted as VA, and the working power supply voltage is denoted as VC. The preset power supply voltage can be set according to the actual situation, such as 4V, 5V, 6V, etc. The working power supply voltage can be set according to the actual situation, such as 3.2V, 3.3V, 3.4V, etc. There are no specific restrictions here.

[0062] The third aspect of this utility model provides an electronic device 2000, such as... Figure 2 As shown, the electronic device 2000 includes an audio system 1000.

[0063] According to the embodiment of the present invention, the electronic device 2000 eliminates pop noise when the audio system 1000 is powered on and off, thereby saving circuit costs and space.

[0064] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0065] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A power-on / off mute control circuit, characterized in that, include: A switching module, wherein the first terminal of the switching module is electrically connected to the output terminal of the audio amplifier circuit, and the second terminal of the switching module is grounded, and the switching module is used to pull down the level at the output terminal of the audio amplifier circuit when it is in the on state; A power supply detection module is provided, wherein a first terminal of the power supply detection module is adapted to receive a reset level signal, a second terminal of the power supply detection module is electrically connected to a third terminal of the switch module, and the power supply detection module is used to control the switching state of the switch module according to the reset level signal.

2. The power-on / off mute control circuit according to claim 1, characterized in that, The power supply detection module includes: A power supply unit, wherein a first end of the power supply unit is adapted to be electrically connected to a power supply, and a second end of the power supply is grounded; A switch control unit, wherein a first terminal of the switch control unit is adapted to receive the reset level signal, a second terminal of the switch control unit is electrically connected to a third terminal of the power supply unit, a third terminal of the switch control unit is electrically connected to a third terminal of the switch module, and a fourth terminal of the switch control unit is grounded. The switch control unit is used to control the switching state of the switch module according to the reset level signal under the power supply.

3. The power-on / off mute control circuit according to claim 2, characterized in that, The power supply unit includes: A first resistor, a first end of which is adapted to be electrically connected to the power supply, and a second end of which is electrically connected to the second end of the switch control unit; The second resistor has its first end electrically connected to the second end of the first resistor and the second end of the switch control unit, and its second end is grounded.

4. The power-on / off mute control circuit according to claim 3, characterized in that, The switch control unit includes: A third resistor, the first end of which is adapted to receive the reset level signal; A capacitor, wherein the first terminal of the capacitor is electrically connected to the second terminal of the third resistor, and the second terminal of the capacitor is grounded; The first transistor has its base electrically connected to the second terminal of the third resistor and the first terminal of the capacitor, its emitter electrically connected to the first terminal of the second resistor and the second terminal of the first resistor, and its collector electrically connected to the third terminal of the switching module. The fourth resistor has its first end electrically connected to the collector of the first transistor and the third end of the switching module, and its second end grounded.

5. The power-on / off mute control circuit according to claim 4, characterized in that, The first transistor is a PNP type transistor.

6. The power-on / off mute control circuit according to any one of claims 1-5, characterized in that, The switching module includes: The first switching unit has a first terminal electrically connected to the left channel output terminal of the audio amplifier circuit, a second terminal grounded, and a third terminal electrically connected to the second terminal of the power supply detection module. The first switching unit is used to pull down the level at the left channel output terminal when it is in the on state. The second switching unit has a first terminal electrically connected to the right channel output terminal of the audio amplifier circuit, a second terminal grounded, and a third terminal electrically connected to the second terminal of the power supply detection module. The second switching unit is used to pull down the level at the right channel output terminal when it is in the on state.

7. The power-on / off mute control circuit according to claim 6, characterized in that, The first switching unit or the second switching unit includes: The fifth resistor, the first end of which is electrically connected to the second end of the power supply detection module; The base of the second transistor is electrically connected to the second terminal of the fifth resistor, the collector of the second transistor is electrically connected to the left channel output terminal / the right channel output terminal, and the emitter of the second transistor is grounded.

8. An audio system, characterized in that, include: Audio amplifier circuit; The power-on / off mute control circuit according to any one of claims 1-7, wherein the power-on / off mute control circuit is electrically connected to the output terminal of the audio amplifier circuit.

9. The audio system according to claim 8, characterized in that, Also includes: An audio control module is provided, wherein a first terminal of the audio control module is adapted to receive an audio control signal, a second terminal of the audio control module is adapted to connect to a working power supply, a third terminal of the audio control module is electrically connected to a preset power supply, a fourth terminal of the audio control module is electrically connected to the third terminal of the switch module in the power-on / off mute control circuit, and a fifth terminal of the audio control module is grounded. The audio control module is used to control the switching state of the switch module according to the audio control signal.

10. An electronic device, characterized in that, Includes the audio system as described in claim 8 or 9.

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