Audio circuit and audio and video playing device

Abstract

The utility model discloses an audio circuit and an audio and video playing device. The audio circuit comprises at least one parallel audio transmission branch, and each audio transmission branch comprises an audio input module used for inputting an audio signal; the audio output module is used for outputting the audio signal; the switch module is connected between the audio input module and the audio output module and is used for connecting the transmission of the audio signal in the audio transmission branch; and the switch control module is connected with the switch module, and the switch control module is used for controlling the on-off of the switch module. According to the technical scheme provided by the embodiment of the utility model, noise generated when the audio circuit is turned on or turned off is eliminated.

Description

Technical Field

[0001] The utility model relates to the technical field of audio, in particular to an audio circuit and an audio-video playing device. Background Art

[0002] With the continuous improvement of people's living quality, the requirements for the quality of life are also getting higher and higher. For some audio-video playing devices, during the startup and shutdown processes, the audio circuit may cause the speaker to output some noise, which inevitably reduces the user experience of the audio-video playing device. Summary of the Utility Model

[0003] The utility model provides an audio circuit and an audio-video playing device to solve the problem of noise generated when the audio circuit starts up or shuts down.

[0004] According to one aspect of the utility model, an audio circuit is provided, including: at least one parallel audio transmission branch

[0005] The audio transmission branch includes:

[0006] An audio input module for inputting an audio signal;

[0007] An audio output module for outputting the audio signal;

[0008] A switch module, which is connected between the audio input module and the audio output module and is used to connect the transmission of the audio signal in the audio transmission branch;

[0009] A switch control module, which is connected to the switch module, and the switch control module is used to control the on-off of the switch module.

[0010] Optionally, the switch module includes: a first transistor, a first end of the first transistor is connected to the audio input module, and a second end of the first transistor is connected to the audio output module;

[0011] The switch control module includes: a first triode, a first end of the first triode is connected to the control end of the first transistor, and a second end of the first triode is grounded.

[0012] Optionally, the audio circuit further includes: a control module, which is connected to the switch control module and the audio input module;

[0013] The control module is used to generate a first control signal within a first time threshold when the audio input module receives the audio signal or stops receiving the audio signal;

[0014] The switch control module is configured to generate a second control signal according to the first control signal; the second control signal is input into the control terminal of the first transistor through the first end of the first triode; the first transistor is configured to turn off according to the second control signal.

[0015] Optionally, the audio transmission branch further includes: a filtering module;

[0016] The filtering module is connected to the audio output module, and the filtering module is configured to filter high-frequency signals in the audio transmission branch.

[0017] Optionally, the filtering module includes: a first capacitor, and the first capacitor is connected between the audio output module and the ground terminal, and the first capacitor is configured to filter high-frequency signals in the audio signal.

[0018] Optionally, the audio transmission branch further includes: a radiation-resistant module;

[0019] The radiation-resistant module is connected to the audio input module, and the radiation-resistant module is configured to filter radiation interference signals from the audio circuit to the outside.

[0020] Optionally, the radiation-resistant module includes: a first inductor, which is connected in series between the audio input module and the switch module.

[0021] Optionally, the audio transmission branch further includes: a soft-start module;

[0022] The soft-start module is connected to the radiation-resistant module, and the soft-start module is configured to slowly start the audio circuit;

[0023] A DC component filtering module; the DC component filtering module includes: a second capacitor;

[0024] The second capacitor is connected between the first inductor and the switch module, and the second capacitor is configured to filter DC components in the audio signal.

[0025] Optionally, the audio circuit further includes: a sounding module, which is connected to the audio output module and is configured to generate sound according to the audio signal.

[0026] According to another aspect of the present invention, there is provided an audio-video playing device, including: the audio circuit according to any embodiment of the present invention.

[0027] In the technical solution provided by the embodiment of the present utility model, by setting a switch control module, the switch module can be turned off at the moment of starting or shutting down the audio circuit, so that the audio signal cannot be output through the audio output module, thereby avoiding the generation of noise. The embodiment of the present utility model does not need to additionally set a new chip for filtering the audio signal, the circuit design is simple, the cost is low, and it has higher applicability.

[0028] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the present utility model, nor is it used to limit the scope of the present utility model. Other features of the present utility model will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0030] Figure 1 is a schematic structural diagram of an audio circuit provided by an embodiment of the present utility model;

[0031] Figure 2 is a schematic structural diagram of another audio circuit provided by an embodiment of the present utility model;

[0032] Figure 3 is a schematic structural diagram of yet another audio circuit provided by an embodiment of the present utility model;

[0033] Figure 4 is a schematic structural diagram of yet another audio circuit provided by an embodiment of the present utility model;

[0034] Figure 5 is a schematic structural diagram of a dual - audio transmission branch provided by an embodiment of the present utility model. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] In order to enable those skilled in the art to better understand the solution of the present utility model, the following will clearly and completely describe the technical solutions in the embodiments of the present utility model with reference to the drawings in the embodiments of the present utility model. Obviously, the described embodiments are only some of the embodiments of the present utility model, rather than all of the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.

[0036] It should be noted that the terms "first", "second", etc. in the description, claims and above-mentioned drawings of the present utility model are used to distinguish similar objects, and do not necessarily have to be used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the present utility model described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0037] An embodiment of the present utility model provides an audio circuit. The circuit includes: at least one parallel audio transmission branch. Figure 1 It is a schematic structural diagram of an audio circuit provided by an embodiment of the present utility model. Refer to Figure 1 , the audio transmission branch includes: an audio input module 1 for inputting an audio signal; an audio output module 2 for outputting an audio signal; a switch module 3 connected between the audio input module 1 and the audio output module 2 for connecting the transmission of the audio signal in the audio transmission branch; a switch control module 4 connected to the switch module 3, and the switch control module 4 is used to control the on / off of the switch module 3.

[0038] Among them, the audio transmission branch is used to transmit audio signals, and multiple audio transmission branches can form the transmission of multi-channel audio signals. Exemplarily, when two audio transmission branches are set, the audio circuit can form left and right channels.

[0039] Specifically, when the audio circuit starts or shuts down instantaneously, the coupling capacitors in the audio circuit will cause interference to the audio transmission branch due to charging and discharging. If at this moment, the audio signal is directly output from the audio output module 2, this audio signal will cause the generation of noise. This noise includes a pop sound, a short sound similar to "bang", resulting in a poor experience in the actual use of the audio circuit.

[0040] To avoid the generation of noise, the switch control module 4 can control the switch module 3 to turn off at the moment when the audio circuit starts or shuts down, so that the audio signal cannot be input into the audio output module 2. Exemplarily, at the moment when the audio circuit starts or shuts down, the switch control module 4 can receive a control signal, and the switch control module 4 converts this control signal into a control signal for controlling the switch module 3 to turn off, thereby controlling the turn-off of the switch module 3. At this time, the audio output module 2 cannot output an audio signal, and thus will not make any sound, thereby avoiding the generation of noise.

[0041] When the audio circuit is fully started and the audio output module 2 needs to output an audio signal, the switch control module 4 can receive a control signal and convert it into a control signal for controlling the switch module 3 to turn on, thereby controlling the switch module 3 to turn on. At this time, the audio output module 2 can normally output an audio signal. And at this time, the audio circuit has been fully started, and the coupling capacitors in the audio circuit have also been fully charged, which will not interfere with the audio transmission branch, so no noise will be generated.

[0042] In the technical solution provided by the embodiment of the present invention, by setting the switch control module 4, the switch module 3 can be turned off at the moment of starting or turning off the audio circuit, so that the audio signal cannot be output through the audio output module 2, thereby avoiding the generation of noise. The embodiment of the present invention does not need to additionally set a new chip for filtering the audio signal, has a simple circuit design, low cost, and higher applicability.

[0043] Figure 2 It is a schematic structural diagram of another audio circuit provided by the embodiment of the present invention. Refer to Figure 2 , on the basis of the above embodiments, optionally, the switch module 3 includes: a first transistor Q1, a first end of the first transistor Q1 is connected to the audio input module 1, and a second end of the first transistor Q1 is connected to the audio output module 2. The switch control module 4 includes: a first triode T1, a first end of the first triode T1 is connected to the control end of the first transistor Q1, and a second end of the first triode T1 is grounded.

[0044] Among them, the first triode T1 can be used to control the turn-off of the first transistor Q1. Compared with the control method in which the control signal directly acts on the control end of the first transistor Q1, the setting method of controlling the first transistor Q1 through the first triode T1 has higher reliability. Exemplarily, there may be reverse injection of current or voltage in the audio circuit, which causes the first transistor Q1 to be accidentally turned on. Setting the first triode T1 can be used to prevent the reverse injection of current or voltage and avoid the accidental turn-on of the first transistor Q1. There may also be leakage current in the audio circuit, which causes the first transistor Q1 to be unable to be turned on. By setting the first triode T1, it can be used to ensure the reliable turn-on of the first transistor Q1.

[0045] Continue to refer to Figure 2 , on the basis of the above embodiments, optionally, the audio circuit further includes: a control module 5, the control module 5 is connected to the switch control module 4 and the audio input module 1. The control module 5 is used to generate a first control signal within a first time threshold when the audio input module 1 receives an audio signal or stops receiving an audio signal. The switch control module 4 is used to generate a second control signal according to the first control signal. The second control signal is input to the control end of the first transistor Q1 through the first end of the first triode T1, and the first transistor Q1 is used to turn off according to the second control signal.

[0046] A first resistor R1 is provided between the first transistor Q1 and the first triode T1. A seventh resistor R7 is connected in parallel between the first end and the control end of the first triode T1. The seventh resistor R7 is used to enable the first transistor Q1 to quickly switch between the on or off states, ensuring that the first transistor Q1 can stably operate in the expected state under different working conditions. A sixth resistor R6 is provided at the second end of the first triode T1. A fifth resistor R5 is provided between the sixth resistor R6 and the ground terminal. The fifth resistor R5 is used to maintain the stability of the audio signal output and reduce the output fluctuations. A second resistor R2 is provided between the control module 5 and the first triode T1, which can be used to limit the current flowing into the first triode T1 and keep it within a safe range. A third capacitor C3 is connected in parallel between the control end and the second end of the first triode T1. A third resistor R3 is connected in series between the third capacitor C3 and the ground terminal, which can be used to provide a grounded potential signal to the first triode T1.

[0047] Among them, at the moment when the audio circuit is started, that is, within the first time threshold, the control module 5 can detect that the audio input module 1 inputs an audio signal. To avoid the noise caused by the direct output of the audio signal through the audio output module 2, the control module 5 generates a first control signal to control the switch control module 4 to turn off the switch module 3. Exemplarily, the control module 5 may include an MCU (Microcontroller Unit) or an SOC (System on Chip).

[0048] Specifically, the first control signal output by the control module 5 is input to the control end of the first triode T1 through the second resistor R2, and the first control signal can be a low-level signal. Also, because the third resistor R3 is grounded, the third resistor R3 can provide a 0 potential signal to the first triode T1. At this time, there is no negative voltage difference between the second end and the control end of the first triode T1, and the first triode T1 is cut off. The first end of the first triode T1 outputs a second control signal. The second control signal can be a high-level signal. Also, because the first end of the first transistor Q1 can receive the audio signal, and the audio signal is also a high-level signal, there is no negative voltage difference between the first end and the control end of the first transistor Q1, and the first transistor Q1 is turned off. At this time, the audio signal cannot be input into the audio output module 2. Therefore, when the audio circuit is powered on, the first triode T1 is in the cut-off state, causing the first transistor Q1 to be turned off, thereby avoiding the noise generated during the startup process.

[0049] After the audio circuit is fully started, when sound needs to be played, the control module 5 outputs a first control signal with a high level. The first triode T1 conducts, and the first end of the first triode T1 outputs a second control signal, and the second control signal is a low-level signal. Also, since the first end of the first transistor Q1 is a high-level signal, a negative pressure difference is formed between the first end and the control end of the first transistor Q1. The first transistor Q1 conducts, and the audio signal is input to the audio output module 2 through the first transistor Q1. At this time, the audio circuit can output the audio signal normally.

[0050] Figure 3 It is a schematic structural diagram of another audio circuit provided by an embodiment of the present invention. Refer to Figure 3 , on the basis of the above embodiments, optionally, the audio transmission branch further includes: a filtering module 6. The filtering module 6 is connected to the audio output module 2, and the filtering module 6 is used to filter high-frequency signals in the audio transmission branch.

[0051] Among them, when the audio circuit is operating, due to the interference of some high-frequency signals, the audio signal output by the audio output module 2 may generate a rattling noise. Exemplarily, the high-frequency signal may include a 2.4 GHz high-frequency signal from a wireless local area network (wifi) in space. By setting the filtering module 6 at the input end of the audio output module 2, the high-frequency signals input to the audio output module 2 can be filtered, thereby avoiding the noise generated by the audio circuit due to the interference of high-frequency signals.

[0052] Continue to refer to Figure 3 , on the basis of the above embodiments, optionally, the filtering module 6 includes: a first capacitor C1. The first capacitor C1 is connected between the audio output module 2 and the ground terminal, and the first capacitor C1 is used to filter high-frequency signals in the audio signal.

[0053] Among them, the first capacitor C1 exhibits a low impedance characteristic to high-frequency signals. When a high-frequency signal passes through the capacitor, the first capacitor C1 will short-circuit the high-frequency signal to the ground, thereby attenuating the high-frequency signal. It is equivalent to a shunt of the high-frequency signal in the audio signal on the first capacitor C1, thereby achieving the purpose of filtering high-frequency signals. Exemplarily, the first capacitor C1 may be a ceramic capacitor.

[0054] Continue to refer to Figure 3 , on the basis of the above embodiments, optionally, the audio transmission branch further includes: an anti-radiation module 7. The anti-radiation module 7 is connected to the audio input module 1, and the anti-radiation module 7 is used to filter the radiation interference signals from the audio circuit to the outside.

[0055] Among them, during the operation of the audio circuit, there may be electromagnetic radiation that affects other components or other circuits outside the circuit. Therefore, by setting the anti-radiation module 7, the radiation generated by the audio circuit can be reduced, making it more reliable and secure.

[0056] Continue to refer to Figure 4 , based on the above embodiments, optionally, the anti-radiation module 7 includes: a first inductor L1, which is connected in series between the audio input module 1 and the switch module 3.

[0057] Among them, the first inductor L1 will generate a hindering effect on the changing current. By setting the first inductor L1 in the audio circuit, the rapid change of the current can be suppressed, thereby reducing the intensity of electromagnetic radiation. In other embodiments, the anti-radiation module 7 may also include a magnetic bead, which has the same beneficial effect as the first inductor L1.

[0058] Figure 4 This is a schematic structural diagram of another audio circuit provided by an embodiment of the present invention. Refer to Figure 4 , based on the above embodiments, optionally, the audio transmission branch further includes: a soft start module 8; the soft start module 8 is connected to the anti-radiation module 7, and the soft start module 8 is used to slowly start the audio circuit.

[0059] Among them, to prevent the impact on the audio circuit caused by the sudden audio signal during the startup process of the audio circuit, the soft start module 8 can be set to gradually increase the audio signal to the rated value. Through this setting method, the stability of the audio circuit during startup can be improved.

[0060] The soft start module 8 includes an eighth resistor R8 and a fourth capacitor C4, which are connected in series between the anti-radiation module 7 and the ground terminal. The soft start module 8 further includes a fourth resistor R4, which is connected in series between the switch module 3 and the ground terminal. The fourth resistor R4 is a pull-down resistor, which can be used to ensure the stability of the audio signal. The eighth resistor R8 and the fourth capacitor C4 can also form an RC filter circuit, and different filter matching can be performed according to different application scenarios of the audio circuit.

[0061] Continue to refer to Figure 4 , based on the above embodiments, optionally, the audio transmission branch further includes: a DC component filtering module 9; the DC component filtering module 9 includes: a second capacitor C2. The second capacitor C2 is connected between the first inductor L1 and the switch module 3, and the second capacitor C2 is used to filter the DC component in the audio signal.

[0062] Among them, by setting the DC component filtering module 9, the DC component in the audio signal can be filtered, thereby avoiding the interference caused by the DC component to the audio signal and improving the purity of the audio signal.

[0063] Continue to refer to Figure 4 , optionally, based on the above embodiments, the audio circuit further includes: a sound generating module 10, connected to the audio output module of the audio output module 2, for generating sound according to the audio signal.

[0064] Among them, the sound generating module 10 may include audio playback devices such as headphones and speakers, for generating sound according to the audio signal.

[0065] Figure 5 This is a schematic structural diagram of a dual audio transmission branch provided by an embodiment of the present invention. Refer to Figure 5 , optionally, based on the above embodiments, the audio circuit includes: a first audio transmission branch 100 and a second audio transmission branch 200. Exemplarily, the first audio transmission branch 100 may be a left-channel audio transmission branch, and the second audio transmission branch 200 may be a right-channel audio transmission branch.

[0066] Among them, the switch control module in the second audio transmission branch 200 includes a second triode T2, whose first end is connected to the control end of the second transistor Q2 through a ninth resistor R9, the control end is connected to the control module 5 through a tenth resistor R10, the second end is grounded through an eleventh resistor R11, and a seventh capacitor R7 is connected in series between the control end and the second end. The switch module includes a second transistor Q2, and a thirteenth resistor R13 is connected in parallel between the first end and the control end of the second transistor Q2, and a fourteenth resistor R14 is connected to the second end. The filtering module includes a fifth capacitor C5, connected between the audio output module 2 and the ground terminal. The anti-radiation module includes a second inductor L2, connected to the audio input module. The soft-start module includes a fifteenth resistor R15 and an eighth capacitor C8, connected in series between the anti-radiation module and the ground terminal, and also includes a twelfth resistor R12, connected in series between the switch module and the ground terminal. The DC component filtering module is a sixth capacitor C6, connected between the second inductor L2 and the switch module. The second audio transmission branch 200 has the same structure as the first audio transmission branch 100, and shares the control module 10 and the audio output module 2.

[0067] An embodiment of the present invention also provides an audio-video playback device. The device includes: the audio circuit provided by any embodiment of the present invention, having the beneficial effects of the audio circuit provided by any of the above embodiments, which will not be elaborated here.

[0068] It should be understood that the various forms of the processes shown above can be used, re-ordered, steps added or deleted. For example, the steps described in the present invention can be executed in parallel, sequentially, or in a different order, as long as the desired results of the technical solution of the present invention can be achieved, and no limitations are made herein.

[0069] The above specific embodiments do not constitute a limitation to the protection scope of the present utility model. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. An audio circuit, characterized in that, Comprising: At least one parallel audio transmission branch, The audio transmission branch includes: An audio input module for inputting an audio signal; An audio output module for outputting the audio signal; A switch module, the switch module is connected between the audio input module and the audio output module for connecting the transmission of the audio signal in the audio transmission branch; A switch control module, the switch control module is connected to the switch module, and the switch control module is used to control the on / off of the switch module.

2. The audio circuit according to claim 1, wherein The switch module includes: a first transistor, a first end of the first transistor is connected to the audio input module, and a second end of the first transistor is connected to the audio output module; The switch control module includes: a first triode, a first end of the first triode is connected to a control end of the first transistor, and a second end of the first triode is grounded.

3. The audio circuit according to claim 2, wherein The audio circuit further includes: a control module, the control module is connected to the switch control module and the audio input module; The control module is configured to generate a first control signal within a first time threshold when the audio input module receives the audio signal or stops receiving the audio signal; The switch control module is configured to generate a second control signal according to the first control signal; the second control signal is input into the control end of the first transistor through the first end of the first triode; the first transistor is configured to turn off according to the second control signal.

4. The audio circuit according to claim 1, characterized in that, The audio transmission branch further includes: a filtering module; The filtering module is connected to the audio output module, and the filtering module is used to filter high-frequency signals in the audio transmission branch.

5. The audio circuit according to claim 4, characterized in that, The filtering module includes: a first capacitor, the first capacitor is connected between the audio output module and the ground terminal, and the first capacitor is used to filter high-frequency signals in the audio signal.

6. The audio circuit according to claim 1, characterized in that The audio transmission branch further includes: an anti-radiation module; The anti-radiation module is connected to the audio input module, and the anti-radiation module is used to filter radiation interference signals from the audio circuit to the outside.

7. The audio circuit according to claim 6, wherein The anti-radiation module includes: a first inductor, connected in series between the audio input module and the switch module.

8. The audio circuit according to claim 7, wherein The audio transmission branch further includes: a soft start module; The soft start module is connected to the anti-radiation module, and the soft start module is used to slowly start the audio circuit; A DC component filtering module; the DC component filtering module includes: a second capacitor; The second capacitor is connected between the first inductor and the switch module, and the second capacitor is used to filter DC components in the audio signal.

9. The audio circuit according to claim 1, wherein The audio circuit further includes: a sounding module, connected to the audio output module, for sounding according to the audio signal.

10. An audio-video playing device, characterized in that, Comprising: The audio circuit according to any one of claims 1-9.

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