Audio output control circuit and electronic device

Abstract

This application discloses an audio output control circuit and electronic device. The circuit includes an audio output circuit and a control circuit. The audio output circuit includes an audio power amplifier and a speaker. The control circuit includes a first switch and a switch control sub-circuit. A first output terminal of the audio power amplifier is connected to a first terminal of the speaker. A second output terminal of the audio power amplifier is connected to a first terminal of the first switch. A second terminal of the first switch is connected to a second terminal of the speaker. An input terminal of the audio power amplifier is connected to a first terminal of the switch control sub-circuit. A second terminal of the switch control sub-circuit is connected to a control terminal of the first switch. The switch control sub-circuit controls the first switch to be turned on or off by detecting the presence of an audio signal at the input terminal of the audio power amplifier.

Description

Technical Field

[0001] This application belongs to the field of electronic technology, specifically relating to an audio output control circuit and electronic device. Background Technology

[0002] With the rapid development of electronic technology, electronic devices have been widely used. Speakers are typically installed in electronic devices to provide audio output.

[0003] Other components can also be deployed on electronic devices. These components may experience intermittent high-current drawdowns during operation, which generate corresponding changing magnetic fields in the designed circuit loop. These changing magnetic fields affect the speaker coil, causing the speaker and audio amplifier to form a low-impedance closed loop even without an audio signal input. This results in a "buzzing" current noise, leading to poor audio output quality from the speaker. Summary of the Invention

[0004] The purpose of this application is to provide an audio output control circuit and electronic device to solve the technical problem of poor audio output quality of speakers in electronic devices, and to improve the audio output quality of speakers in electronic devices.

[0005] In a first aspect, embodiments of this application provide an audio output control circuit, including an audio output circuit and a control circuit. The audio output circuit includes an audio power amplifier and a speaker, and the control circuit includes a first switching element and a switching control sub-circuit.

[0006] The first output terminal of the audio power amplifier is connected to the first terminal of the speaker, the second output terminal of the audio power amplifier is connected to the first terminal of the first switch, the second terminal of the first switch is connected to the second terminal of the speaker, the input terminal of the audio power amplifier is connected to the first terminal of the switch control sub-circuit, and the second terminal of the switch control sub-circuit is connected to the control terminal of the first switch.

[0007] The switch control sub-circuit controls the first switch to be turned on or off by detecting the presence of an audio signal at the input terminal of the audio power amplifier.

[0008] Secondly, embodiments of this application provide an electronic device, including the audio output control circuit as described in the first aspect.

[0009] In this embodiment, a control circuit is provided in the audio output control circuit. This control circuit includes a first switch and a switch control sub-circuit. The first output terminal of the audio power amplifier in the audio output control circuit is connected to the first terminal of the speaker in the audio output control circuit. The second output terminal of the audio power amplifier is connected to the first terminal of the first switch, and the second terminal of the first switch is connected to the second terminal of the speaker. The input terminal of the audio power amplifier is connected to the first terminal of the switch control sub-circuit, and the second terminal of the switch control sub-circuit is connected to the control terminal of the first switch. The switch control sub-circuit controls the first switch to be turned on or off by detecting the presence of an audio signal at the input terminal of the audio power amplifier. Thus, when an audio signal is detected at the input terminal of the audio power amplifier, the switch control sub-circuit turns the first switch on, forming a loop between the audio power amplifier and the speaker to output audio. When no audio signal is detected at the input terminal of the audio power amplifier, the switch control sub-circuit turns the first switch off, breaking the loop between the audio power amplifier and the speaker, avoiding a buzzing sound, and thereby improving the audio output quality of the speaker. Attached Figure Description

[0010] Figure 1 This is one of the structural schematic diagrams of the audio output control circuit provided in the embodiments of this application;

[0011] Figure 2 This is a second schematic diagram of the audio output control circuit provided in the embodiments of this application;

[0012] Figure 3 It is a schematic diagram of the waveforms before and after the audio signal is amplified by the amplifier circuit;

[0013] Figure 4 It is a waveform diagram before and after half-wave rectification by the rectifier circuit;

[0014] Figure 5 This is a schematic diagram of a DC signal obtained by integrating a half-sine wave signal.

[0015] Figure 6 This is a schematic diagram showing the relationship between the intermittently input audio signal and the output signal of the discharge circuit;

[0016] Figure 7 This is a schematic diagram of the audio output control circuit provided in the embodiment of this application. Detailed Implementation

[0017] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0018] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0019] The audio output control circuit provided in this application will be described in detail below with reference to the accompanying drawings, through specific embodiments and application scenarios.

[0020] Figure 1 This is one of the structural schematic diagrams of the audio output control circuit provided in the embodiments of this application, such as... Figure 1 As shown, the audio output control circuit includes an audio output circuit 11 and a control circuit 12. The audio output circuit 11 includes an audio power amplifier 111 and a speaker 112. The control circuit 12 includes a first switch 121 and a switch control sub-circuit 122.

[0021] The first output terminal of the audio power amplifier 111 is connected to the first terminal of the speaker 112, the second output terminal of the audio power amplifier 111 is connected to the first terminal of the first switch 121, the second terminal of the first switch 121 is connected to the second terminal of the speaker 112, the input terminal of the audio power amplifier 111 is connected to the first terminal of the switch control sub-circuit 122, and the second terminal of the switch control sub-circuit 122 is connected to the control terminal of the first switch 121.

[0022] The switch control sub-circuit 122 controls the first switch 121 to be turned on or off by detecting the presence of an audio signal at the input terminal of the audio power amplifier 111.

[0023] The audio output circuit 11 may include an audio power amplifier 111 and a speaker 112. When the audio power amplifier 111 and the speaker 112 form a circuit, the speaker 112 will be energized. When the current passes through the coil in the speaker 112, a magnetic field will be generated around it. This magnetic field can drive the diaphragm of the speaker, thereby making the speaker 112 produce sound.

[0024] The audio power amplifier 111 is a device that amplifies the audio signal. The audio signal can be provided by the central processing unit (CPU) of the electronic device. When the electronic device has an audio output requirement, the CPU can control the audio power amplifier 111 to turn on, and when audio output is required, the audio signal is input to the audio power amplifier 111, so that the audio power amplifier 111 amplifies the audio signal and provides the audio signal of the power amplifier based on the circuit of the audio power amplifier 111 and the speaker 112, driving the speaker 112 to output audio.

[0025] The speaker 112 is a device that outputs audio. The speaker 112 can be composed of a coil, which is affected by a magnetic field. In some scenarios, when a third-party application installed on an electronic device is opened, although it does not provide external audio playback, the CPU will trigger the audio power amplifier to turn on because it needs to provide audio output to the third-party application. In this scenario, if the device deployed in the electronic device generates a corresponding changing magnetic field in the designed circuit loop, and this changing magnetic field affects the speaker coil, the speaker and the audio power amplifier will form a low-impedance closed loop even without an audio signal input, resulting in a "buzzing" current noise. This phenomenon is more pronounced in electronic devices with increasingly compact layouts. For example, if the speaker in an electronic device is close to the motherboard, or even directly placed in the motherboard's projection area, this "buzzing" current noise is more noticeable, leading to a poor user experience.

[0026] In related technologies, to prevent interference signals from affecting the normal operation of the speaker, a resistor is usually connected in series in the speaker circuit to reduce the current of the interference signal. However, this solution of connecting a resistor in series in the speaker circuit reduces the current of the audio signal input to the speaker, which reduces the loudness of the audio played by the speaker.

[0027] In related technologies, interference sources to the speaker can be sampled, a compensation signal can be generated through a processing module, and the compensation signal can be output to the speaker. The compensation signal and the interference signal cancel each other out, allowing the speaker to function normally. However, this solution has some drawbacks. For example, if there are many interference sources to the speaker, the process of sampling multiple interference sources and generating compensation signals through a processing module is very complex. If the phases of the compensation signal and the interference signal are not aligned, the compensation signal will become the interference signal, which will make the interference sound from the speaker even more severe.

[0028] In this embodiment, a first switch 121 is provided in the middle of the line between the audio power amplifier 111 and the speaker 112. The first switch 121 can be controlled by a switch control sub-circuit 122. The switch control sub-circuit 122 controls the first switch 121 to be turned on or off by detecting the presence of the audio signal at the input terminal of the audio power amplifier 111.

[0029] The first switch 121 can control the connection or disconnection of the circuit between the audio power amplifier 111 and the speaker 112 by turning the first switch 121 on or off. When the first switch 121 is on, the circuit between the audio power amplifier 111 and the speaker 112 is connected, creating a closed loop and outputting sound. When the first switch 121 is off, the circuit between the audio power amplifier 111 and the speaker 112 is disconnected, thus breaking the closed loop created by the circuit between the audio power amplifier 111 and the speaker 112, preventing the "buzzing" current noise phenomenon.

[0030] Wherein, the first switch 121 being on means that the first end and the second end of the first switch 121 are in a conductive state, and the first switch 121 being off means that the first end and the second end of the first switch 121 are in a disconnected state.

[0031] In some embodiments, since the audio signal is an AC signal, the first switching element 121 can be a bidirectional switch, that is, the first switching element 121 can be a device that conducts current bidirectionally.

[0032] In some embodiments, the first switch 121 can be controlled by a wireless signal. In some embodiments, since the audio signal has a relatively large voltage peak after being amplified by the audio power amplifier 111, the first switch 121 can be controlled by a relatively large voltage value to turn it on, that is, the first switch 121 can be controlled by a high-voltage signal conducted by the line.

[0033] In some embodiments, the first switching element 121 may be a packaged device of a bidirectional switch, which may have a control terminal that can be controlled by the switch control sub-circuit 122.

[0034] In some embodiments, the first switching element 121 may be a circuit composed of some devices. In some embodiments, the first switching element 121 may include a first switching unit and a second switching unit, which may be an N-type metal-oxide-semiconductor (NMOS) transistor or a device of the same type as an NMOS transistor.

[0035] In some embodiments, the first and second switching units are exemplified by NMOS transistors. The gates of the two NMOS transistors can be connected together, the sources of the two NMOS transistors can be connected together, and the drains of the two NMOS transistors can be connected between the lines of the audio power amplifier 111 and the speaker 112, respectively. That is, the drain of one NMOS transistor can be connected to the second output terminal of the audio power amplifier 111, and the drain of one NMOS transistor can be connected to the second terminal of the speaker 112. In this way, when the gate voltage of the NMOS transistor is relatively large, such that the voltage difference between the gate and the source is greater than the threshold voltage, the first and second switching units will be controlled to conduct simultaneously. When the gate voltage of the NMOS transistor is relatively small, such that the voltage difference between the gate and the source is less than the threshold voltage, the first and second switching units will be controlled to de-convert simultaneously. Thus, by controlling the gate voltage of the NMOS transistor, the conduction or de-conversion of the first switching device can be controlled.

[0036] In some embodiments, the switch control sub-circuit 122 may be a controller that can control the first switch 121 by sending wireless signals.

[0037] In some embodiments, the switch control sub-circuit 122 may also be a circuit composed of some devices, which can control the first switch 121 by transmitting voltage signals through the lines.

[0038] In some embodiments, the switch control sub-circuit 122 can determine whether an audio signal exists at the input terminal of the audio power amplifier 111 by detecting the magnitude of the signal voltage value at the input terminal of the audio power amplifier 111. For example, if the detected signal voltage value at the input terminal is greater than zero, it is determined that an audio signal exists at the input terminal of the audio power amplifier 111; if the detected signal voltage value at the input terminal is equal to zero, it is determined that no audio signal exists at the input terminal of the audio power amplifier 111.

[0039] In some embodiments, the switch control sub-circuit 122 can also detect the presence of an audio signal at the input terminal of the audio power amplifier 111 by detecting the signal waveform at the input terminal of the audio power amplifier 111. In this way, the presence of an audio signal can be detected by taking advantage of the waveform characteristics of the sine wave of the audio signal.

[0040] In some embodiments, the switch control subcircuit 122 can detect the presence of an audio signal at the input of the audio power amplifier 111 using a second switch. For example, the second switch can be in different on / off states depending on the presence of an audio signal at the input of the audio power amplifier 111. When an audio signal is present at the input of the audio power amplifier 111, the second switch is on; when no audio signal is present at the input of the audio power amplifier 111, the second switch is off. This way, the different signals transmitted through the line when the second switch is on or off can affect the control signal of the first switch 121, thereby enabling the first switch 121 to switch between on and off under different control signals transmitted by the switch control subcircuit 122.

[0041] In some embodiments, when the switch control sub-circuit 122 detects that there is no audio signal at the input terminal of the audio power amplifier 111, it can control the first switch 121 to open, thereby disconnecting the closed loop between the audio power amplifier 111 and the speaker 112, thereby preventing the changing magnetic field generated by other components of the electronic device from affecting the speaker coil and causing a "buzzing" current sound phenomenon to occur.

[0042] In some embodiments, when the switch control sub-circuit 122 detects that there is an audio signal at the input terminal of the audio power amplifier 111, it can control the first switch 121 to be turned on, thereby forming a closed loop between the audio power amplifier 111 and the speaker 112, and outputting the audio corresponding to the audio signal.

[0043] In this embodiment, a control circuit 12 is provided in the audio output control circuit. This control circuit 12 includes a first switch 121 and a switch control sub-circuit 122. The first output terminal of the audio power amplifier 111 in the audio output control circuit is connected to the first terminal of the speaker 112 in the audio output control circuit. The second output terminal of the audio power amplifier 111 is connected to the first terminal of the first switch 121, and the second terminal of the first switch 121 is connected to the second terminal of the speaker 112. The input terminal of the audio power amplifier 111 is connected to the first terminal of the switch control sub-circuit 122, and the second terminal of the switch control sub-circuit 122 is connected to the control terminal of the first switch 121. The switch control sub-circuit 122 controls the first switch 121 to be turned on or off by detecting the presence of an audio signal at the input terminal of the audio power amplifier 111. In this way, the switch control sub-circuit can control the first switch to turn on when an audio signal is detected at the input of the audio power amplifier, so that the audio power amplifier and the speaker form a circuit and output audio. When no audio signal is detected at the input of the audio power amplifier, the first switch is controlled to turn off to disconnect the circuit between the audio power amplifier and the speaker, so as to avoid the "buzzing" current noise phenomenon and thus improve the audio output quality of the speaker.

[0044] That is, the first switch 121 controls the opening and closing of the speaker 112 path. When the audio power amplifier 111 has an input signal, the first switch 121 is turned on, the speaker 112 path forms a closed loop, and the speaker 112 can work normally. At this time, even if the current noise generated by the external interference magnetic field is covered by the normal audio output, the "buzzing" current noise cannot be heard. When the first switch 121 is turned off, the speaker 112 path is disconnected, the speaker 112 cannot work normally, and similarly, the external interference magnetic field cannot interfere with the coil of the speaker 112 to generate the "buzzing" current noise.

[0045] In some embodiments, the switch control subcircuit 122 can control the first switch 121 by conducting a voltage signal through a line. Optionally, Figure 2 This is a second schematic diagram of the audio output control circuit provided in the embodiments of this application, as shown below. Figure 2 As shown, the switch control sub-circuit 122 includes a first conversion sub-circuit 1221 and a second conversion sub-circuit 1222; the input terminal of the audio power amplifier 111 is connected to the first terminal of the first conversion sub-circuit 1221, the second terminal of the first conversion sub-circuit 1221 is connected to the first terminal of the second conversion sub-circuit 1222, and the second terminal of the second conversion sub-circuit 1222 is connected to the control terminal of the first switch 121;

[0046] The first conversion sub-circuit 1221 is used to convert the audio signal at the input terminal of the audio power amplifier 111 into a DC signal to obtain a first DC signal. The second conversion sub-circuit 1222 is used to perform level conversion on the first level value in the first DC signal to obtain a second DC signal. The second DC signal includes a second level value obtained based on the first level value. The first level value is the level value obtained based on the audio signal. The second level value is greater than the first level value. The second DC signal is used to control the first switch 121 to be turned on.

[0047] In some embodiments, the audio signal can be a sinusoidal voltage signal, and its signal value is usually relatively small, such as a small sinusoidal signal of a few millivolts (mV) to several hundred mV. To ensure that the first switch 121 remains continuously on when an audio signal is input, the control signal for the first switch 121 can be a DC signal. Therefore, the audio signal at the input of the audio power amplifier 111 can be converted into a DC signal by the first conversion sub-circuit 1221 to obtain the first DC signal.

[0048] In some embodiments, the control voltage value of the first switching element 121 is typically relatively large, and in order to keep the first switching element 121 continuously in the on state, the control voltage of the first switching element 121 must typically be kept at a high voltage. Therefore, the first level value in the first DC signal can be level-converted by the second conversion sub-circuit 1222 to obtain a second DC signal, wherein the second level value in the second DC signal is greater than the first level value.

[0049] Thus, when an audio signal is present at the input of the audio power amplifier 111, the first DC signal obtained by converting the audio signal through the first conversion sub-circuit 1221 and the second conversion sub-circuit 1222 can be used to control the first switch 121 to conduct. This allows the first conversion sub-circuit 1221 to first convert the audio signal into a lower voltage signal that is easier to generate, and then into a DC signal, to control the first switch 121 to remain on. Then, the second conversion sub-circuit 122 converts the low-voltage signal into a high-voltage signal, thereby converting the high-voltage signal used to control the first switch 121 into a lower voltage signal that is easier to generate, simplifying the control of the first switch 121.

[0050] In some embodiments, when there is no audio signal at the input of the audio power amplifier 111, the first conversion sub-circuit 1221 and the second conversion sub-circuit 1222 may not operate, preventing the control signal of the downstream first switch 121 from turning on the first switch 121. In some embodiments, a discharge circuit may also be provided after the first conversion sub-circuit 1221 or the second conversion sub-circuit 1222. In this way, when the first switch 121 is in the on state, if no audio signal is detected at the input of the audio power amplifier 111, the discharge circuit can discharge the signal to control the first switch 121 to turn off.

[0051] In some embodiments, a branch can also be provided so that if the first switch 121 is turned on when no audio signal is detected at the input of the audio power amplifier 111, the first switch 121 can be turned off through the branch. Alternatively, if the first switch 121 is turned off, the control signal of the first switch 121 at the rear end can be prevented from turning on the first switch 121 through the branch.

[0052] In some embodiments, the first conversion sub-circuit 1221 can convert the audio signal into a DC signal via an integrator circuit. Optionally, as... Figure 2 As shown, the first conversion sub-circuit 1221 includes an amplification sub-circuit 12211 and an integrator sub-circuit 12212; the input terminal of the audio power amplifier 111 is connected to the first terminal of the amplification sub-circuit 12211, the second terminal of the amplification sub-circuit 12211 is connected to the first terminal of the integrator sub-circuit 12212, and the second terminal of the integrator sub-circuit 12212 is connected to the first terminal of the second conversion sub-circuit 1222.

[0053] The amplification sub-circuit 12211 is used to amplify the audio signal to obtain an audio AC signal, and the integrator sub-circuit 12212 is used to integrate the audio AC signal to obtain the first DC signal.

[0054] Since the audio signal value is relatively small, it can be amplified by the amplification sub-circuit 12211. In some embodiments, the amplification sub-circuit 12211 can amplify the small sinusoidal signal to a large sinusoidal signal at the level of 1 to 2 volts (V), so that after level conversion by the second conversion sub-circuit 1222, the control voltage level that enables the first switching element 121 to be turned on can be achieved.

[0055] Figure 3 This is a schematic diagram of the waveforms of the audio signal before and after amplification by the amplifier circuit, such as... Figure 3As shown, curve 301 is the sine wave waveform before amplification, and curve 302 is the sine wave waveform after amplification. The signal value of the amplified sine wave is significantly greater than that of the sine wave before amplification.

[0056] In some embodiments, the amplified sine wave can be integrated by the integrator circuit 12212 to convert the AC signal into a DC signal. In this way, by converting the AC signal into a DC signal that can continuously control the first switching element 121 to conduct, the control stability of the first switching element 121 can be guaranteed.

[0057] If a sine wave signal is directly passed through the integrator circuit 12212, the resulting DC signal may have a relatively small amplitude. In some embodiments, such as... Figure 2 As shown, the first conversion sub-circuit 1221 further includes a rectifier sub-circuit 12213; the second terminal of the amplification sub-circuit 12211 is connected to the first terminal of the integrator sub-circuit 12212 through the rectifier sub-circuit 12213.

[0058] The rectifier circuit 12213 is used to perform half-wave rectification on the audio AC signal to obtain a half-wave shaped signal, and the integrator circuit 12212 is specifically used to integrate the half-wave shaped signal to obtain the first DC signal.

[0059] In other words, in this embodiment, a half-wave rectifier can be added between the amplification sub-circuit 12211 and the integrator sub-circuit 12212 to intercept the negative half-cycle of the sine wave. In this way, the DC level obtained by integration by the integrator sub-circuit 12212 will be closer to the peak value of the sine wave.

[0060] like Figure 4 As shown, it is a schematic diagram of the waveforms before and after half-wave rectification by the rectifier circuit, as follows: Figure 4 As shown, curve 401 is the waveform without half-wave shaping, and curve 402 is the waveform after half-wave rectification. Compared with the waveform of curve 401, the negative half-cycle of the sine wave in curve 402 is intercepted, that is, the voltage value of the negative half-cycle is converted to zero level.

[0061] Then, the integrator circuit 12212 can convert the half-sine wave signal after half-wave rectification into a DC signal with smaller sawtooth patterns, thereby continuously controlling the on / off state of the first switching device 121 at the downstream end. For example, as Figure 5 As shown, a half-sine wave signal with a short duration or intermittent time can be represented as... Figure 5 As shown in the left-middle figure, after integration by the integrator circuit 12212, a sawtooth-shaped DC signal can be output, such as... Figure 5As shown in the middle right figure, and the signal value is relatively large, after level conversion by the second conversion sub-circuit 1222, a high voltage signal with a relatively large voltage can be output, so that the first switch 121 at the back end remains in the conducting state. Thus, when there is an audio signal at the input end of the audio power amplifier 111, continuous control of the first switch 121 can be achieved.

[0062] In some embodiments, such as Figure 2 As shown, the first conversion sub-circuit 1221 further includes an electron discharge circuit 12214; the second terminal of the integrator sub-circuit 12212 is connected to the first terminal of the second conversion sub-circuit 1222 through the electron discharge circuit 12214.

[0063] The discharge circuit 12214 is used to discharge based on the first DC signal when there is no audio signal at the input terminal of the audio power amplifier, so as to control the first switch 121 to open.

[0064] In some embodiments, the electronic device does not continuously output audio. If the audio output needs to be turned off after the input audio signal, the first switch 121 needs to be turned off within a set time to switch the output circuit of the speaker. In this scenario, a discharge circuit 12214 can be set after the integrator circuit 12212 to discharge based on the first DC signal when there is no audio signal at the input of the audio power amplifier 111.

[0065] Since the voltage value at the first terminal of the second conversion sub-circuit 1222 is a first DC signal, during the discharge process, the second level value converted by the second conversion sub-circuit 1222 cannot turn on the first switch 121, and the first switch 121 is turned off accordingly. Furthermore, if the voltage value at the first terminal of the second conversion sub-circuit 1222 discharges below a certain value, the second conversion sub-circuit 1222 cannot perform its level conversion function. This may cause the control terminal voltage of the first switch 121 to fail to turn on the first switch 121, and the first switch 121 will also be turned off accordingly.

[0066] Figure 6 This is a schematic diagram showing the relationship between intermittently input audio signals and the output signal of the amplifier circuit, as shown below. Figure 6As shown, when the audio signal 601 is intermittently input, it is necessary to dynamically control the first switch 121 to be turned on or off. At the audio signal input time 602, the integrator circuit 12212 can perform integration processing on the audio signal, and its discharge circuit 12214 does not work. Its output can be the same as the output signal of the integrator circuit 12212. At the end of the audio signal input, or at the beginning of the negative half-cycle before the end of the audio signal input 603, the discharge circuit 12214 can start discharging based on the first DC signal until it discharges to zero level.

[0067] Thus, by setting an electronic discharge circuit 12214 in the first conversion sub-circuit 1221, the presence of the audio signal at the input terminal of the audio power amplifier 111 can be detected by setting only one branch in the switch control sub-circuit 122. Furthermore, the conduction and cutoff of the first switch 121 can be dynamically controlled based on the presence of the audio signal at the input terminal of the audio power amplifier 111, resulting in a simple circuit design.

[0068] In some embodiments, Figure 7 This is a schematic diagram of the audio output control circuit provided in an embodiment of this application, as shown below. Figure 7 As shown, the amplification sub-circuit 12211 includes a second switching element 122111; the input terminal of the audio power amplifier 111 is connected to the control terminal of the second switching element 122111, the first terminal of the second switching element 122111 is connected to the first voltage source 122112 and the first terminal of the integrating sub-circuit 12212 respectively, and the second terminal of the second switching element 122111 is connected to the ground terminal;

[0069] When an audio signal is present at the input of the audio power amplifier 111, the audio signal can control the second switch 122111 to be turned on, so as to amplify the audio signal and obtain an audio AC signal.

[0070] The voltage value of the first voltage source can be 3V.

[0071] In this embodiment, the amplification sub-circuit 12211 uses a second switch 122111 to detect whether there is an audio signal at the input of the audio power amplifier 111. When there is an audio signal at the input of the audio power amplifier 111, the second switch 122111 is turned on; when there is no audio signal at the input of the audio power amplifier 111, the second switch 122111 is turned off. When the second switch 122111 is turned on, the audio signal can be amplified.

[0072] The second switching element 122111 can be an NPN transistor or other devices of the same type. Taking an NPN transistor as an example, the control terminal of the second switching element 122111 can be the base, the first terminal of the second switching element 122111 can be the collector, and the second terminal of the second switching element 122111 can be the emitter. When an audio signal is input to the base terminal, the voltage between the base and the emitter exceeds the conduction threshold of the second switching element 122111, causing the second switching element 122111 to conduct. The amplifier sub-circuit 12211 can then amplify the audio signal, and the first conversion sub-circuit 1221 and the second conversion sub-circuit 1222 begin to operate, controlling the first switching element 121 to conduct. When no audio signal is input to the base terminal, the second switch 122111 is open, the amplifier sub-circuit 12211 can not work, the first conversion sub-circuit 1221 and the second conversion sub-circuit 1222 can not work, the amplifier circuit 12214 starts working, and controls the first switch 121 to open.

[0073] Thus, by setting a second switch 122111 in the amplification sub-circuit 12211, the presence of the audio signal at the input terminal of the audio power amplifier 111 can be detected through the second switch 122111. The amplification sub-circuit 12211 can simultaneously have the functions of audio signal detection and amplification.

[0074] In some embodiments, such as Figure 7 As shown, the amplification sub-circuit 12211 may further include a second capacitor 122113, a third capacitor 122114, a third resistor 122115, a fourth resistor 122116, and a fifth resistor 122117. The second capacitor 122113 is connected between the input terminal of the audio power amplifier 111 and the control terminal of the second switch 122111, and its function is to limit current. The third capacitor 122114 is connected between the first terminal of the second switch 122111 and one end of the rectifier sub-circuit 12213. The third resistor 122115 is connected between the first voltage source 122112 and the first terminal of the second switch 122111, and its function is to limit current. The fourth resistor 122116 is connected between the second terminal of the second switch 122111 and the ground terminal, and its function is to limit current. One end of the fifth resistor 122117 is connected to the control terminal of the second switch 122111, and the other end is connected to one end of the first voltage source 122112, and its function is to regulate voltage.

[0075] In some embodiments, such as Figure 7 As shown, rectifier circuit 12213 is a half-wave rectifier, which is a packaged device.

[0076] In some embodiments, such as Figure 7As shown, the integrator circuit 12212 includes a first resistor 122121 and a first capacitor 122122, and the amplifier circuit 12214 includes a second resistor 122141. One end of the first resistor 122121 is connected to the second end of the amplifier circuit 12211, and the other end of the first resistor 122121 is connected in series with the first capacitor 122122. The second resistor 122141 is connected in parallel with the first capacitor 122122. The second resistor 122141 is connected in parallel between the first end of the second conversion circuit 1222 and the ground end.

[0077] This simplifies the design of the integrator circuit 12212 and the discharge circuit 12214. This implementation method is a pure hardware control design, which can avoid the complex software design of phase control, amplitude cancellation, etc.

[0078] In some embodiments, such as Figure 7 As shown, the second conversion sub-circuit 1222 includes a third switch 12221 and a fourth switch 12222. The second terminal of the first conversion sub-circuit 1221 is connected to the control terminal of the third switch 12221. The first terminal of the third switch 12221 is connected to the control terminals of the second voltage source 12223 and the fourth switch 12222, respectively. The first terminal of the fourth switch 12222 is connected to the control terminals of the second voltage source 12223 and the first switch 1221, respectively. The second terminals of the third switch 12221 and the fourth switch 12222 are respectively connected to the ground terminal.

[0079] When an audio signal is present at the input of the audio power amplifier 111, the second level value of the control terminal of the fourth switch 12222 can control the first switch 121 to turn on; when no audio signal is present at the input of the audio power amplifier, the third level value of the control terminal of the fourth switch 12222 can control the first switch 121 to turn off.

[0080] The third switch 12221 can be an NMOS transistor or a device of the same type as an NMOS transistor, and the fourth switch 12222 can also be an NMOS transistor or a device of the same type as an NMOS transistor.

[0081] In some embodiments, the control terminal of the third switching element 12221 can be the gate of an NMOS transistor, the first terminal of the third switching element 12221 can be the drain, and the second terminal of the third switching element 12221 can be the source.

[0082] In some embodiments, the control terminal of the fourth switch 12222 can be the gate of an NMOS transistor, the first terminal of the fourth switch 12222 can be the drain of an NMOS transistor, and the second terminal of the fourth switch 12222 can be the source of an NMOS transistor.

[0083] In some embodiments, when an audio signal is present at the input of the audio power amplifier 111, the output signal of the discharge circuit 12214 and the integrator circuit 12212 is the same, which is a first DC signal. At this time, the third switch 12221 is turned on, the fourth switch 12222 is turned off, the drain of the fourth switch 12222 outputs a high level, and the first switch 121 is turned on. When there is no audio signal at the input of the audio power amplifier 111, the discharge circuit 12214 discharges based on the first DC signal. When the discharge reaches a certain level, the third switch 12221 is turned off, the fourth switch 12222 is turned on, the drain of the fourth switch 12222 outputs a low level, and the first switch 121 is turned off.

[0084] The voltage value of the second voltage source can be greater than that of the first voltage source, and it can be 9V.

[0085] In some embodiments, such as Figure 7 As shown, the second conversion sub-circuit 1222 may further include a sixth resistor 12224 and a seventh resistor 12225, which are connected in series. One end of the sixth resistor 12224 is connected to the second voltage source 12223, and one end of the seventh resistor 12225 is connected to the drain of the third switching element 12221. The function of the sixth resistor 12224 and the seventh resistor 12225 is to limit current.

[0086] In some embodiments, the first switching element 121 includes a first switching unit 1211 and a second switching unit 1212. The control terminals of the first switching unit 1211 and the second switching unit 1212 are both connected to the second terminal of the switch control sub-circuit 122. The first terminal of the first switching unit 1211 is connected to the second output terminal of the audio power amplifier 111. The first terminal of the second switching unit 1212 is connected to the second terminal of the speaker 112. The second terminal of the first switching unit 1211 is connected to the second terminal of the second switching unit 1212.

[0087] When both the first switching unit 1211 and the second switching unit 1212 are turned on, the first switching element 121 is turned on; when either the first switching unit 1211 or the second switching unit 1212 is turned off, the first switching element 121 is turned off.

[0088] In some embodiments, the control terminal of the first switching unit 1211 can be the gate of an NMOS transistor, the first terminal of the first switching unit 1211 can be the drain, and the second terminal of the first switching unit 1211 can be the source.

[0089] In some embodiments, the control terminal of the second switching unit 1212 can be the gate of an NMOS transistor, the first terminal of the second switching unit 1212 can be the drain of an NMOS transistor, and the second terminal of the second switching unit 1212 can be the source of an NMOS transistor.

[0090] In some embodiments, the first switching element 121 may further include an eighth resistor 1213 and a fourth capacitor 1214, which are connected in series. One end of the eighth resistor 1213 is connected to the first end of the first switching unit 1211, and one end of the fourth capacitor 1214 is connected to the control end of the first switching unit 1211. The function of the eighth resistor 1213 and the fourth capacitor 1214 is to stabilize the voltage.

[0091] This application also provides an electronic device that may include the audio output control circuit provided in the above embodiments, which can provide audio output for the electronic device.

[0092] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, it should be noted that the scope of the methods and apparatuses in the embodiments of this application is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

[0093] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a computer software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause an electronic device (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of this application.

[0094] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. An audio output control circuit, characterized in that, It includes an audio output circuit and a control circuit. The audio output circuit includes an audio power amplifier and a speaker. The control circuit includes a first switching element, an amplification sub-circuit, a half-wave rectifier, an integrator sub-circuit, an amplification circuit, and a second conversion sub-circuit. The first output terminal of the audio power amplifier is connected to the first terminal of the speaker, the second output terminal of the audio power amplifier is connected to the first terminal of the first switch, the second terminal of the first switch is connected to the second terminal of the speaker, the input terminal of the audio power amplifier is connected to the first terminal of the amplification sub-circuit, the second terminal of the amplification sub-circuit is connected to the first terminal of the integrator sub-circuit through the half-wave rectifier, the second terminal of the integrator sub-circuit is connected to the first terminal of the second conversion sub-circuit through the discharge circuit, and the second terminal of the second conversion circuit is connected to the control terminal of the first switch. The amplification sub-circuit is used to amplify the audio signal at the input terminal of the audio power amplifier to obtain an audio AC signal; the half-wave rectifier is used to perform half-wave rectification on the audio AC signal to obtain a half-wave shaped signal; the integrator sub-circuit is used to integrate the half-wave shaped signal to obtain a first DC signal; the discharge circuit is used to discharge based on the first DC signal when there is no audio signal at the input terminal of the audio power amplifier, so as to control the first switching device to open. The second conversion sub-circuit is used to convert the first level value in the first DC signal to obtain a second DC signal. The second DC signal includes a second level value obtained based on the first level value. The first level value is a level value obtained based on the audio signal. The second level value is greater than the first level value. The second DC signal is used to control the first switch to be turned on. The second conversion sub-circuit includes a third switch and a fourth switch. The second terminal of the integrating sub-circuit is connected to the control terminal of the third switch through the discharge circuit. The first terminal of the third switch is connected to the control terminal of the second voltage source and the fourth switch respectively. The first terminal of the fourth switch is connected to the control terminal of the second voltage source and the first switch respectively. The second terminals of the third switch and the fourth switch are connected to the ground terminal respectively. When an audio signal is present at the input of the audio power amplifier, the second level value of the control terminal of the fourth switch can control the first switch to be turned on; when no audio signal is present at the input of the audio power amplifier, the third level value of the control terminal of the fourth switch can control the first switch to be turned off.

2. The circuit according to claim 1, characterized in that, The amplification sub-circuit includes a second switching element; the input terminal of the audio power amplifier is connected to the control terminal of the second switching element, the first terminal of the second switching element is connected to the first voltage source and the first terminal of the integrating sub-circuit, and the second terminal of the second switching element is connected to the ground terminal. When an audio signal is present at the input of the audio power amplifier, the audio signal can control the second switch to turn on, thereby amplifying the audio signal to obtain an audio AC signal.

3. The circuit according to claim 1, characterized in that, The integrator circuit includes a first resistor and a first capacitor, and the amplification circuit includes a second resistor; one end of the first resistor is connected to the second end of the amplification circuit, the other end of the first resistor is connected in series with the first capacitor, and the second resistor is connected in parallel with the first capacitor; the second resistor is connected in parallel between the first end of the second conversion circuit and the ground terminal.

4. The circuit according to claim 1, characterized in that, The first switching device includes a first switching unit and a second switching unit. The second terminal of the integrator circuit is connected to the control terminal of the first switching unit and the control terminal of the second switching unit respectively through the discharge circuit. The first terminal of the first switching unit is connected to the second output terminal of the audio power amplifier. The first terminal of the second switching unit is connected to the second terminal of the speaker. The second terminal of the first switching unit is connected to the second terminal of the second switching unit. When both the first switching unit and the second switching unit are turned on, the first switching element is turned on; when either the first switching unit or the second switching unit is turned off, the first switching element is turned off.

5. An electronic device, characterized in that, Includes the audio output control circuit as described in any one of claims 1-4.

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