Audio processing methods, electronic devices and computer-readable media

Abstract

This application provides an audio processing method, an electronic device, and a computer-readable medium. The method includes detecting that a first frequency of a first audio signal to be processed belongs to a first frequency range; adjusting the amplitude of the first audio signal based on a first target amplitude corresponding to the first frequency to obtain a second audio signal; and providing the second audio signal to a piezoelectric loudspeaker to drive the piezoelectric loudspeaker to emit sound, wherein the current generated by the second audio signal input to the piezoelectric loudspeaker is lower than the critical current of overcurrent protection. This application can prevent the operating circuit of the piezoelectric loudspeaker from triggering overcurrent protection due to playing high-frequency audio signals.

Description

Technical Field

[0001] This application relates to the field of smart terminal technology, and in particular to an audio processing method, electronic device, and computer-readable medium. Background Technology

[0002] A piezoelectric loudspeaker typically consists of a housing, a diaphragm, and a vibrating element. The vibrating element is a piezoelectric sheet made of piezoelectric ceramic material. See also Figure 1 The working principle of a piezoelectric loudspeaker is generally as follows: Utilizing the inverse piezoelectric effect of a piezoelectric element, applying a voltage causes it to extend upwards or contract downwards, thereby causing the diaphragm on the piezoelectric element to vibrate up and down, which in turn causes the air above the diaphragm to vibrate, thus producing sound. Specifically, when the upper surface O1 of the piezoelectric element is connected to the negative terminal of the voltage and the lower surface O2 is connected to the positive terminal, the piezoelectric element will extend upwards due to the generated mechanical stress; when the upper surface O3 is connected to the positive terminal and the lower surface O4 is connected to the negative terminal, the piezoelectric element will contract downwards due to the generated mechanical stress. Due to their thin size and low power consumption, piezoelectric loudspeakers are increasingly used in electronic devices such as mobile phones, tablets, and wearable devices.

[0003] However, since the impedance of a piezoelectric element is significantly affected by the frequency of the input signal, when high-frequency signals are present in the audio played by electronic devices such as mobile phones, the impedance of the piezoelectric element decreases under the instantaneous excitation of these high-frequency signals. This may lead to excessive transient current, triggering overcurrent protection. Overcurrent protection will cause the speaker's operating circuit to stop working for a certain period of time, which may interrupt audio playback and result in a poor user experience. Summary of the Invention

[0004] This application provides an audio processing method, an electronic device, and a computer-readable medium. This audio processing method can avoid triggering overcurrent protection while ensuring the playback effect of the audio signal in scenarios where the frequency of the audio signal played by the piezoelectric speaker is high and / or the temperature of the piezoelectric speaker is high, thus guaranteeing the user experience.

[0005] In a first aspect, this application provides an audio processing method, the method comprising: detecting that a first frequency of a first audio signal to be processed belongs to a first frequency range; adjusting the amplitude of the first audio signal based on a first target amplitude corresponding to the first frequency to obtain a second audio signal; providing the second audio signal to a piezoelectric loudspeaker to drive the piezoelectric loudspeaker to emit sound, wherein the current generated by the second audio signal input to the piezoelectric loudspeaker is lower than the critical current of overcurrent protection.

[0006] Thus, based on the influence of the frequency of the audio signal input to the piezoelectric speaker on the piezoelectric impedance of the speaker, the frequency range of the audio signal that is likely to trigger overcurrent protection can be determined, and this frequency range can be used as the aforementioned first frequency range. Furthermore, a first target amplitude corresponding to each frequency within this first frequency range can be determined. This first target amplitude ensures that the current generated by the second audio signal input to the piezoelectric speaker within the first frequency range is lower than the critical current of the overcurrent protection, thereby preventing the piezoelectric speaker's operating circuit from triggering overcurrent protection due to the current exceeding the critical current. In one exemplary embodiment, the first target amplitude ensures that the current generated by the second audio signal input to the piezoelectric speaker is lower than and close to the critical current. Therefore, when the second audio signal is input to the piezoelectric speaker for playback, the loudness of the second audio signal played by the piezoelectric speaker is close to the maximum loudness that the piezoelectric speaker can play. Here, the aforementioned critical current can be referred to as the standard current.

[0007] In one possible implementation of the first aspect described above, adjusting the amplitude of a first audio signal to obtain a second audio signal based on a first target amplitude corresponding to a first frequency includes: determining that the amplitude of the first audio signal is higher than the first target amplitude, adjusting the amplitude of the first audio signal to the first target amplitude, and obtaining the second audio signal. Here, the current generated by the audio signal with an amplitude higher than the first target amplitude within the first frequency range input to the piezoelectric loudspeaker is higher than a critical current.

[0008] For example, in one exemplary embodiment, the boundary amplitude that does not trigger overcurrent protection for each frequency of the audio signal within a first frequency range can be used as the first target amplitude for that frequency. For instance, the first target amplitude could be a boundary amplitude that causes the current generated by the piezoelectric speaker corresponding to the second audio signal input to be lower than and close to a standard current. In another exemplary embodiment, the amplitude adjustment parameter after adjusting the aforementioned boundary amplitude by an amplitude margin can be used as the first target amplitude for that frequency. This avoids triggering overcurrent protection due to transient changes in the current in the piezoelectric speaker's operating circuit.

[0009] Understandably, when the amplitude of an audio signal within the first frequency range is less than its corresponding boundary amplitude, overcurrent protection will not be triggered. Therefore, no amplitude reduction adjustment is needed for this type of audio signal. However, a first audio signal with an amplitude exceeding the first target amplitude within the first frequency range will trigger overcurrent protection. When processing the first audio signal, only its amplitude is adjusted to the first target amplitude to obtain the second audio signal. Therefore, it can be ensured that the tone of the second audio signal played by the piezoelectric speaker is consistent with that of the first audio signal, and only the loudness is suppressed to approximately the maximum loudness that the piezoelectric speaker can play. Understandably, audio signals exceeding this maximum loudness will be unable to play due to triggering overcurrent protection.

[0010] Therefore, based on the aforementioned method, the playback effect of audio signals that do not trigger overcurrent protection remains unchanged, and the first audio signal that would otherwise be unable to play due to overcurrent protection can be played with a playback effect close to the optimal performance that the piezoelectric speaker can deliver. In this way, overcurrent protection is avoided while ensuring the playback effect of the audio signal, thus guaranteeing the user experience.

[0011] In one possible implementation of the first aspect above, providing a second audio signal to a piezoelectric speaker to drive the piezoelectric speaker to emit sound includes: providing the second audio signal to the piezoelectric speaker such that the piezoelectric speaker outputs a first current, wherein the first current is lower than a critical current.

[0012] Here, the amplitude of the second audio signal is the aforementioned first target amplitude. Since the first target amplitude can make the first current generated by the second audio signal input to the piezoelectric speaker lower than and close to the standard current that triggers overcurrent protection, the second audio signal input to the piezoelectric speaker will not trigger overcurrent protection.

[0013] In one possible implementation of the first aspect above, providing a second audio signal to a piezoelectric speaker to cause the piezoelectric speaker to output a first current includes: providing the second audio signal to the piezoelectric speaker based on a first voltage to cause the piezoelectric speaker to output a first current, wherein the first voltage is the driving voltage of the piezoelectric speaker that provides the second audio signal to the first impedance, and the first impedance is the impedance of the piezoelectric speaker corresponding to the first frequency.

[0014] For example, based on the relationship between the amplitude of an audio signal and the driving voltage required by the piezoelectric speaker to play the audio signal, the driving voltage required by the piezoelectric speaker to play the second audio signal can be reduced to a first voltage by reducing the amplitude of the first audio signal to a first target amplitude. Since the first impedance of the piezoelectric speaker is relatively small under the influence of the first frequency, by reducing the driving voltage to the first voltage, the first current in the piezoelectric speaker's operating circuit can be controlled to be lower than and close to the standard current that triggers overcurrent protection.

[0015] In one possible implementation of the first aspect described above, adjusting the amplitude of the first audio signal to obtain a second audio signal based on a first target amplitude corresponding to a first frequency includes: detecting that the current first temperature of the piezoelectric loudspeaker belongs to a first temperature range; and adjusting the amplitude of the first audio signal to obtain the second audio signal based on the first target amplitude corresponding to the first frequency and a first amplitude adjustment amount corresponding to the first temperature.

[0016] For example, based on the effect of temperature on the impedance of the piezoelectric element of the piezoelectric speaker, the first temperature range that triggers overcurrent protection for such audio signals can be determined by observing the changes in current in the piezoelectric speaker's operating circuit when an audio signal with a boundary amplitude is input to the piezoelectric speaker under different temperature conditions. Within this first temperature range, because the higher temperature causes a decrease in the impedance of the piezoelectric element, such audio signals that would not normally trigger overcurrent protection may trigger it due to the increased current in the operating circuit. Therefore, a first amplitude adjustment amount corresponding to each temperature within the first temperature range can be determined to reduce the current in the operating circuit to less than and close to the standard current when such audio signals are input to the piezoelectric speaker. Here, the aforementioned first amplitude adjustment amount can be called the compensation amplitude, and the first temperature can be called temperature information.

[0017] Understandably, adjusting the amplitude of the first audio signal based on the first target amplitude can avoid the influence of frequency factors on triggering overcurrent protection; adjusting the amplitude of the first audio signal based on the first amplitude adjustment amount can avoid the influence of temperature factors on triggering overcurrent protection. Therefore, the second audio signal obtained by amplitude adjustment based on the first target amplitude and the first amplitude adjustment amount can avoid overcurrent protection in scenarios where its own frequency is relatively high and / or the piezoelectric speaker temperature is high.

[0018] In one possible implementation of the first aspect described above, adjusting the amplitude of a first audio signal to obtain a second audio signal based on a first target amplitude corresponding to a first frequency and a first amplitude adjustment amount corresponding to a first temperature includes: adjusting the amplitude of the first audio signal to a second target amplitude to obtain the second audio signal, wherein the second target amplitude is a target amplitude determined after adjusting the first target amplitude based on the first amplitude adjustment amount. Here, an audio signal with an amplitude higher than the second target amplitude within the first frequency range input to a piezoelectric loudspeaker within the first temperature range generates a current higher than a critical current.

[0019] For example, the difference between the first target amplitude and the first amplitude adjustment amount can be used as the second target amplitude. Understandably, when the amplitude of an audio signal within the first frequency range is less than the second target amplitude, the current generated by the piezoelectric speaker inputting that audio signal into the first temperature range is below the critical current, and overcurrent protection will not be triggered. Therefore, amplitude reduction adjustment is not necessary for this type of audio signal. However, inputting a first audio signal with an amplitude greater than the second target amplitude into the piezoelectric speaker within the first temperature range will trigger overcurrent protection. When processing the first audio signal, only its amplitude is adjusted to the second target amplitude to obtain the second audio signal. Similarly, overcurrent protection can be avoided while ensuring the playback effect of the audio signal, thus protecting the user experience.

[0020] In one possible implementation of the first aspect above, providing the second audio signal to the piezoelectric speaker includes: providing the second audio signal to the piezoelectric speaker based on a second voltage, wherein the second voltage is a driving voltage required to provide the second audio signal to the piezoelectric speaker with a second impedance, wherein the second impedance is the impedance of the piezoelectric speaker corresponding to a first frequency and a first temperature, and wherein the second impedance is less than the first impedance of the piezoelectric speaker corresponding to the first frequency.

[0021] Here, under the influence of the first temperature, the impedance of the piezoelectric speaker further decreases to a second impedance based on the aforementioned first impedance. Therefore, the aforementioned first voltage may not be able to control the current in the piezoelectric speaker's operating circuit below the standard current, triggering overcurrent protection. Therefore, it is necessary to further reduce the driving voltage of the piezoelectric speaker. This can be achieved by reducing the amplitude of the first audio signal to a second target amplitude to obtain the second audio signal, thus further reducing the driving voltage required for the piezoelectric speaker to play the second audio signal to a second voltage. Since the second impedance of the piezoelectric speaker is less than the first impedance under the combined influence of the first frequency and the first temperature, further reducing the driving voltage to a second voltage lower than the first voltage allows the current in the piezoelectric speaker's operating circuit to remain below and close to the standard current that triggers overcurrent protection.

[0022] In a second aspect, this application provides an electronic device comprising: one or more processors; one or more memories; the one or more memories storing one or more programs, which, when executed by one or more processors, cause the electronic device to perform the audio processing method provided by the first aspect and various possible implementations of the first aspect.

[0023] Thirdly, this application provides a computer-readable medium storing instructions that, when executed on a computer, cause the computer to perform the audio processing method provided by the first aspect and various possible implementations of the first aspect. Attached Figure Description

[0024] Figure 1 A schematic diagram of a piezoelectric loudspeaker provided for an embodiment of this application;

[0025] Figure 2 A schematic diagram of an audio playback scenario provided for an embodiment of this application;

[0026] Figure 3a Experimental data table for the piezoelectric loudspeaker operating circuit provided for embodiments of this application;

[0027] Figure 3b The implementation method provided in this application is based on Figure 3a Fitting curves of experimental data;

[0028] Figure 4a A comparison diagram of the frequency-impedance curves of the piezoelectric element of the piezoelectric loudspeaker provided in the embodiments of this application;

[0029] Figure 4b Frequency-capacitance diagram of the piezoelectric element of the piezoelectric loudspeaker provided in the embodiments of this application;

[0030] Figure 5a A working circuit diagram of a piezoelectric loudspeaker provided for an embodiment of this application;

[0031] Figure 5b The implementation method provided in this application is based on Figure 5a The experimental test curves obtained from the working circuit;

[0032] Figure 5c A frequency-amplitude adjustment parameter curve of a piezoelectric loudspeaker provided for an embodiment of this application;

[0033] Figure 5d Frequency-drive voltage curve of the operating circuit provided in the embodiments of this application;

[0034] Figure 6a Temperature-capacitance curve of the piezoelectric element of the piezoelectric loudspeaker provided in the embodiments of this application;

[0035] Figure 6b Frequency-impedance curves of the piezoelectric element of the piezoelectric loudspeaker under different temperature conditions provided for embodiments of this application;

[0036] Figure 6c A comparison diagram of the temperature-capacitance curves of the piezoelectric element of the piezoelectric loudspeaker provided in the embodiments of this application;

[0037] Figure 6d Temperature-compensation amplitude curve of a piezoelectric loudspeaker provided for embodiments of this application;

[0038] Figure 7a Another working circuit diagram of a piezoelectric loudspeaker provided for an embodiment of this application;

[0039] Figure 7b A flowchart illustrating an implementation method for an audio processing method provided in this application;

[0040] Figure 7c A comparison diagram of the playback loudness of audio signals provided in the embodiments of this application;

[0041] Figure 8 An exception handling block diagram provided for an embodiment of this application;

[0042] Figure 9 A schematic diagram of a mobile phone structure provided for an embodiment of this application. Detailed Implementation

[0043] The specific embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0044] To facilitate understanding of the solutions in the embodiments of this application by those skilled in the art, some concepts involved in the embodiments of this application will be explained below.

[0045] (1) Audio signal: It is composed of several single-frequency signals with different frequencies and amplitudes (or "amplitude" or "vibration amplitude") superimposed.

[0046] (2) Frequency domain: Points in the frequency domain represent single-frequency signals. The horizontal axis is the frequency of the single-frequency signal, and the vertical axis is the amplitude of the single-frequency signal. Therefore, the frequency domain can intuitively represent the individual single-frequency signals that make up the audio signal.

[0047] (3) Overcurrent protection (OCP): This refers to a passive protection mechanism designed to prevent damage to components in a circuit due to excessive current. It is usually manifested as an overcurrent protection circuit. Its principle is as follows: when the detected current exceeds the standard current value, the power supply to the load is cut off; when the current does not exceed the standard current value, the power supply to the load is restored.

[0048] Figure 2 An audio playback scenario diagram is shown according to an embodiment of this application.

[0049] like Figure 2 As shown, the scenario includes a mobile phone 100, which uses a piezoelectric speaker as its sound-producing element. Users can operate the mobile phone 100 to play music or record audio files. During the playback of an audio file, because the piezoelectric speaker circuit of the mobile phone 100 typically has an overcurrent protection mechanism, audio playback may be interrupted or stuttered when the mobile phone 100 plays high-frequency segments of the audio file.

[0050] To avoid triggering overcurrent protection, a common approach is to incorporate a high-power resistor into the piezoelectric speaker's circuitry. This resistor effectively suppresses the overall current flow, ensuring that even when the input audio signal frequency is high, the current will not exceed the overcurrent protection threshold. However, this solution increases the load on the piezoelectric speaker's circuitry, leading to increased power consumption in devices like mobile phones. Furthermore, this approach also results in suppressed current even when the input audio signal frequency is low, causing the loudness of the audio output to be lower than expected.

[0051] Therefore, the technical solution provided in this application aims to solve the problem of effectively preventing high-frequency signals from triggering overcurrent protection in the piezoelectric speaker's operating circuit without increasing the additional power consumption of the piezoelectric speaker's operating circuit or affecting the loudness of the audio output by the piezoelectric speaker.

[0052] To address the aforementioned problems, this application first investigates the frequency range corresponding to the audio signal input to the piezoelectric loudspeaker, which is prone to triggering overcurrent protection in the operating circuit. For example, refer to... Figure 3a The experimental data shown for the operating circuit of a certain type of piezoelectric loudspeaker reveals that when the frequency of the audio signal is below 1kHz, the current in the operating circuit of the piezoelectric loudspeaker (reference) is... Figure 3a The "raw current" in the data table shown can be stabilized below the standard current value of 1.2A, for example. Figure 3a The original current shown is 0.33A for 500Hz and 0.78A for 900Hz. However, when the audio signal frequency is in the range of 1kHz to 20kHz, the current in the piezoelectric speaker's operating circuit can easily exceed 1.2A, for example... Figure 3a The original current shown is 1.455A corresponding to 3kHz and 24.32A corresponding to 19kHz. This indicates that when using this type of piezoelectric speaker to process audio signals, the frequency range of audio signals that are likely to trigger overcurrent protection should be from 1kHz to 20kHz.

[0053] After determining the frequency range that is likely to trigger overcurrent protection, this application further analyzes the critical amplitude (hereinafter referred to as boundary amplitude) of the corresponding audio signal that will not trigger overcurrent protection, and then determines the amplitude adjustment parameters of the audio signal at the corresponding frequency based on the amplitude.

[0054] It can be understood that an audio signal is a superposition of several single-frequency signals, and the energy E of each single-frequency signal depends on the amplitude A of the corresponding single-frequency signal, where E is proportional to A. 2 Therefore, the larger the amplitude of the audio signal, the greater the energy, and the greater the driving voltage required from the piezoelectric speaker's operating circuit. (Reference) Figure 3a The experimental data shown reveals that as the amplitude of audio signals at different frequencies decreases, the driving voltage in the piezoelectric speaker circuit also decreases, leading to a reduction in the current. Therefore, the amplitude of audio signals within the frequency range that easily triggers overcurrent protection can be reduced to decrease the high initial current generated when these signals are input to the piezoelectric speaker circuit due to their higher frequency. For example, when a 3kHz audio signal is adjusted from its initial amplitude of 0dB to a boundary amplitude of -4dB, the current can be reduced from the initial current of 1.455A to the standard current of 1.2A.

[0055] By analogy, the boundary amplitude values ​​corresponding to audio signals in each frequency band within the frequency range that are prone to triggering overcurrent protection can be analyzed. These boundary amplitude values ​​ensure that the current value of the piezoelectric loudspeaker's operating circuit is equal to or close to the standard current value corresponding to the overcurrent protection limit when processing audio signals of the corresponding frequency. Based on these boundary amplitude values, the amplitude of audio signals within the frequency range that are prone to triggering overcurrent protection can be reduced before the audio signal is input to the piezoelectric loudspeaker, thereby reducing the current in the piezoelectric loudspeaker's operating circuit to below the corresponding standard current value.

[0056] It is understandable that, in the actual process of adjusting the amplitude of the corresponding frequency audio signal based on the above boundary amplitudes, in order to ensure that the current of the piezoelectric speaker's operating circuit does not exceed the standard current value, a partial amplitude margin can be lowered from the above boundary amplitudes and used as the amplitude adjustment parameter for the corresponding frequency audio signal. The amplitude margin can be set based on empirical values, such as 1dB, 2dB, etc., and is not limited here. For example, refer to... Figure 3a As shown, based on the boundary amplitude of -4dB corresponding to a 3kHz audio signal, the amplitude adjustment parameter for the corresponding audio signal can be set to -5dB; based on the boundary amplitude of -5dB corresponding to a 4kHz audio signal, the amplitude adjustment parameter for the corresponding audio signal can be set to -6dB.

[0057] Therefore, by adjusting the amplitude of the audio signal at the corresponding frequency based on the aforementioned amplitude adjustment parameters before inputting it into the piezoelectric speaker for playback, the current in the piezoelectric speaker's operating circuit can be controlled to not exceed the standard current value. For example, after inputting a 3kHz audio signal adjusted by -5dB amplitude adjustment parameter into the piezoelectric speaker, the driving voltage of the corresponding operating circuit can be reduced to 7.65V, and the current can be adjusted to 0.87A; after inputting a 4kHz audio signal adjusted by -6dB amplitude adjustment parameter into the piezoelectric speaker, the driving voltage of the corresponding operating circuit can be reduced to 6.94V, and the current can be adjusted to 1.04A, and so on, all without exceeding the standard current value of 1.2A.

[0058] The audio processing method provided in this application can be implemented based on the above. Figure 3a The experimental data shown were fitted to Figure 3b The frequency-amplitude relationship curve is shown. Figure 3b As shown, the horizontal axis of the frequency-amplitude relationship curve represents the frequency of the audio signal, and the vertical axis represents the amplitude of the audio signal. For comparison, Figure 3bThe frequency-amplitude relationship curves shown may include a frequency-original amplitude curve 301, a frequency-boundary amplitude curve 302, and a frequency-amplitude adjustment parameter curve 303. When the frequency of the audio signal input to the piezoelectric loudspeaker exceeds 1kHz, the audio signal with the original amplitude corresponding to the frequency-original amplitude curve 301 above the frequency-boundary amplitude curve 302 is more likely to trigger the overcurrent protection of the operating circuit. However, the audio signal with amplitude adjusted according to the amplitude adjustment parameters corresponding to the frequency-amplitude adjustment parameter curve 303 below the frequency-boundary amplitude curve 302 will never trigger the overcurrent protection of the operating circuit. Therefore, when implementing the audio processing method provided in this application, it is possible to utilize... Figure 3b The frequency-amplitude adjustment parameter curve 303 shown is used as a control curve to adjust the amplitude of the audio signal at the corresponding frequency before it is input to the piezoelectric speaker for processing.

[0059] Understandably, by reducing the amplitude of the audio signal according to the frequency-amplitude adjustment parameter curve 303, the current value of the piezoelectric loudspeaker's operating circuit when processing the audio signal can approach the standard current value corresponding to the overcurrent protection limit. However, since the piezoelectric element's impedance decreases due to increased temperature, if the current value of the piezoelectric loudspeaker's operating circuit is still to approach the standard current value when processing the audio signal, the driving voltage of the piezoelectric loudspeaker needs to be further reduced. Therefore, by reducing the amplitude adjustment parameter, the driving voltage of the piezoelectric loudspeaker when processing the audio signal can be further reduced, thereby ensuring that the current value of the piezoelectric loudspeaker's operating circuit approaches the standard current value and does not trigger overcurrent protection due to temperature increase.

[0060] Therefore, under different temperature conditions, this application can determine corresponding compensation adjustment parameters to compensate for the amplitude of the audio signal after the amplitude adjustment parameters based on the aforementioned frequency are adjusted, thereby further reducing the amplitude of the corresponding audio signal. Based on the above compensation adjustment parameters, even when the piezoelectric impedance of the piezoelectric speaker further decreases due to the corresponding temperature, the amplitude of the corresponding audio signal can still be controlled so that the current value of the corresponding operating circuit does not exceed the standard current value limited by the overcurrent protection.

[0061] Specifically, the aforementioned process of determining compensation adjustment parameters corresponding to different temperature conditions can also be achieved by fitting a temperature-compensation adjustment parameter curve based on experimental data obtained from testing. For example, when the temperature of the piezoelectric speaker is detected to exceed the corresponding temperature threshold, a compensation adjustment parameter matching the detected temperature can be determined based on the fitted temperature-compensation adjustment parameter curve. Then, the amplitude of the already adjusted audio signal is further adjusted using this compensation adjustment parameter. In other embodiments, the matched compensation adjustment parameter can also be used to compensate and correct the amplitude adjustment parameter determined based on the frequency-amplitude adjustment parameter curve 303, and then the corrected amplitude adjustment parameter can be used to adjust the initial amplitude of the audio signal. This application does not impose any limitations on this method.

[0062] It is understood that the audio processing method provided in this application embodiment can be applied to electronic devices including but not limited to mobile phones, tablets, desktops, laptops, handheld computers, netbooks, augmented reality (AR) / virtual reality (VR) devices, smart TVs, smartwatches and other wearable devices, in-vehicle devices, portable game consoles, portable music players, televisions with one or more processors embedded or coupled thereto, or other electronic devices that can play audio and are equipped with piezoelectric speakers as sound-producing devices.

[0063] To facilitate understanding of the specific implementation process of the audio processing method provided in this application, the process of establishing the frequency-amplitude adjustment parameter curve 303, which serves as the control curve, will be described in detail below with reference to the corresponding accompanying drawings. Then, with reference to the corresponding flowchart, the specific implementation process of adjusting the amplitude of the audio signal at the corresponding frequency based on the frequency-amplitude adjustment parameter curve 303 will be explained in detail.

[0064] Figure 4a The embodiments of this application illustrate frequency-impedance curves and comparison curves showing the change in impedance of the piezoelectric element of a piezoelectric loudspeaker as a function of the frequency of the input signal. It is understood that the piezoelectric element of the piezoelectric loudspeaker can be made of piezoelectric ceramic. The material composition of the piezoelectric ceramic affects the impedance of the piezoelectric element to some extent, but the impedance of piezoelectric elements made from piezoelectric ceramics with different material compositions exhibits similar or consistent patterns of change with the input signal frequency.

[0065] like Figure 4a As shown, the impedance of an ideal capacitor changes with frequency, typically exhibiting the following characteristics: Figure 4aThe impedance curve 401 of the ideal capacitor shows the variation pattern. On curve 401, the impedance of the ideal capacitor has a linear negative correlation with the change in frequency. For example, when the frequency changes from 200KHz to 1000KHz, the impedance of the ideal capacitor can decrease from 0.08Ω to below 0.02Ω.

[0066] The impedance of an ideal inductor varies with the frequency of the input signal, which typically exhibits the following characteristics: Figure 4a The curve 402 shows the variation of the impedance of the ideal inductor. On this curve 402, the impedance of the ideal inductor exhibits a linear positive correlation with the frequency of the input signal. For example, when the frequency of the input signal increases from 100kHz to 1000kHz, the impedance of the ideal capacitor can increase from 0.002Ω to 0.02Ω.

[0067] In addition, there may be some dielectric losses and electrode losses in the working circuit of a piezoelectric loudspeaker. If these losses are represented as equivalent series resistance (ESR), the impedance of this ESR also changes with the frequency of the input signal. The corresponding variation pattern can be found by referring to... Figure 4a The ESR curve 403 is shown. The impedance of the ESR curve 403 varies between 0.01Ω and 0.1Ω, which indicates that the impedance caused by dielectric loss and electrode loss in the working circuit of the piezoelectric loudspeaker is relatively small, and the corresponding impact of this part of the impedance on the total impedance of the working circuit is also relatively small.

[0068] Continue to refer to Figure 4a As shown, based on the experimental data on the impedance of the piezoelectric element of the piezoelectric loudspeaker as a function of frequency, a corresponding fit can be obtained. Figure 4a The piezoelectric impedance curve 404 is shown. On this curve 404, if the frequency of the input signal driving the piezoelectric loudspeaker is in a low range, such as the frequency range corresponding to 0MHz to 1MHz, the piezoelectric impedance will gradually decrease as the input signal frequency increases. For example, when the frequency of the input signal changes from 20kHz to 200kHz, the corresponding piezoelectric impedance can decrease from 0.9Ω to a value below 0.08Ω.

[0069] Continue to refer to Figure 4a As shown by curve 404, if the frequency of the input signal driving the piezoelectric loudspeaker is in a high range, such as the frequency range corresponding to 1000kHz to 10000kHz, then the piezoelectric impedance will gradually increase as the input signal frequency increases. For example, when the input signal frequency changes from 3000kHz to 10000kHz, the corresponding piezoelectric impedance can increase from 0.06Ω to 0.2Ω. Figure 4aAs shown, when the frequency of the input signal is in the range of 0KHz to 10000KHz, the piezoelectric impedance curve 404 generally exhibits a V-shaped or U-shaped curve.

[0070] Based on the variation patterns of the ideal capacitor impedance curve 401, the ideal inductor impedance curve 402, and the ESR impedance curve 403, it can be understood that the variation pattern corresponding to the piezoelectric impedance curve 404 is due to the technological and structural characteristics of the piezoelectric element used in the piezoelectric loudspeaker and the material properties of the piezoelectric ceramic material used in the piezoelectric element. Analysis reveals that when the input signal frequency is within a certain range, the impedance change of the piezoelectric element made of piezoelectric ceramic may exhibit a similar variation pattern to the ideal capacitor impedance curve 401; while when the input signal frequency is within another range, the impedance change of the piezoelectric element may exhibit a similar variation pattern to the ideal capacitor impedance curve 402.

[0071] Compare Figure 4a As shown in Figures 401 (ideal capacitor impedance), 402 (ideal inductor impedance), and 403 (ESR impedance), the piezoelectric impedance curve 404 approximates the ideal capacitor impedance curve 401 when the input signal frequency is in the lower range of 0kHz to 10000kHz. The difference between the two is reflected in the magnitude of the ESR impedance on curve 403. In this case, the impedance characteristic of the piezoelectric element can be approximately equivalent to that of an ideal capacitor. Similarly, when the input signal frequency is in the higher range of 1000kHz to 10000kHz, the piezoelectric impedance curve 401 approximates the ideal inductor impedance curve 402, and the difference between the two is again reflected in the magnitude of the ESR impedance on curve 403. In this case, the impedance characteristic of the piezoelectric element can be equivalent to that of an ideal inductor.

[0072] The frequency range of the audio signal is 20Hz to 20KHz, which is within the aforementioned lower range of 0KHz to 10000KHz. Based on the above conclusion, when the input signal is an audio signal, the impedance characteristics of the piezoelectric element can be approximately equivalent to the impedance characteristics of an ideal capacitor. Therefore, the impedance of the piezoelectric element when the piezoelectric loudspeaker processes the audio signal can be calculated using the calculation formula (1) determined by the frequency-impedance relationship of an ideal capacitor.

[0073]

[0074] Accordingly, the formula for calculating the current value flowing through the piezoelectric loudspeaker can be found in the following formula (2):

[0075]

[0076] Therefore, the formula (3) for calculating the current flowing through the piezoelectric loudspeaker can be derived:

[0077] I = V·2πfC L (3)

[0078] Where f is the frequency of the audio signal input to the piezoelectric loudspeaker, and C L V is the capacitance of the piezoelectric loudspeaker, V is the driving voltage of the piezoelectric loudspeaker when processing the input audio signal, and I is the current flowing through the piezoelectric loudspeaker.

[0079] Based on formula (3), in order to stabilize the current I in the working circuit of the piezoelectric loudspeaker, it is necessary to control the driving voltage V, the frequency f of the audio signal, and the capacitance C of the piezoelectric sheet of the piezoelectric loudspeaker. L The numerical product is relatively constant.

[0080] It can be understood that the above formula (3) corresponds to the determined capacitance value C. L The pattern of frequency variation of audio signals can be observed through... Figure 4b The capacitance-frequency variation curve shown illustrates this. For example... Figure 4b As shown, within the frequency range of 20Hz to 20kHz that is perceptible to the human ear, the capacitance C of the piezoelectric element increases with the increase of the frequency f of the audio signal. L The magnitude of the current I remains constant. Therefore, within the audio signal frequency range of 20Hz to 20kHz, the change in current I in the piezoelectric loudspeaker's operating circuit is only affected by the change in driving voltage V and the change in audio signal frequency f. It should be clarified here that, unless otherwise specified, the audio signals described below refer to audible audio signals within the range of 20Hz to 20kHz.

[0081] Therefore, when the frequency f of the input audio signal increases, it is necessary to reduce the driving voltage V of the piezoelectric speaker when processing the audio signal in order to stabilize the current I in the working circuit of the piezoelectric speaker.

[0082] As mentioned earlier, the larger the amplitude A of the audio signal, the larger the driving voltage V required for the piezoelectric speaker to process the audio signal. Therefore, in this embodiment, when the frequency f of the input audio signal increases to a frequency range that easily triggers overcurrent protection, the driving voltage V of the piezoelectric speaker to process the audio signal can be reduced by decreasing the amplitude A of the audio signal, thereby stabilizing the current I in the piezoelectric speaker's operating circuit below the standard current value corresponding to overcurrent protection.

[0083] Therefore, based on the above conclusions, this application can use experimental testing to find the boundary amplitude at which the current I in the piezoelectric loudspeaker's operating circuit reaches the standard overcurrent protection value I_max. Then, based on the found boundary amplitude, the amplitude adjustment parameters for the corresponding frequency audio signal are determined.

[0084] Furthermore, Figure 5a The circuit diagram of a piezoelectric loudspeaker is shown.

[0085] In the embodiments of this application, it can be based on Figure 5a The circuit shown was tested experimentally to determine the boundary amplitude corresponding to the audio signal at the corresponding frequency.

[0086] like Figure 5a As shown, the operating circuit 500A includes a power supply 501, a power amplifier 502, and a piezoelectric speaker 503. The power amplifier 502 includes a boost converter 502a and a modulator 502b. The power supply 501 provides the power amplifier 502 with a supply voltage V. BAT The power amplifier 502, based on the boost converter 502a, converts the supply voltage V... BAT Magnified to V BST And based on the boost voltage V BST The drive voltage V required for the piezoelectric loudspeaker 503 to process the input audio signal. OUT The modulator 502b includes an overcurrent protection circuit that limits the maximum current flowing through the power amplifier 502 to the piezoelectric speaker 503 to a standard current value I_max. In some embodiments, the modulator 502b may be a Class D amplifier modulator or a modulator with similar functionality; this application does not specify its specific type.

[0087] This application is based on the above. Figure 5a The experimental test process for the 500A working circuit shown is as follows:

[0088] A test signal can be input to the power amplifier 502 via an audio analyzer, and the original amplitude of this test signal should be relatively large. For example, see the above. Figure 3a The test signal for the input power amplifier 502 can include audio signals distributed at different frequencies, wherein the frequencies of each audio signal can be distributed between 100Hz and 20kHz, for example including... Figure 3a The table shows 29 example audio signals. The original amplitude of each audio signal can be 0dB, which is the maximum amplitude of the audio signal.

[0089] During the simulation experiment, when the audio signals included in the test signal are input into the working circuit 500A, the experimenter can monitor the current value I of each audio signal after it is input into the working circuit 500A and flows through the power amplifier 502 to the piezoelectric speaker 503 using an audio analyzer. L (refer to Figure 3a The data in the table shows the "raw current" and the driving voltage V supplied by the power amplifier 502 to the piezoelectric speaker 503. OUT Therefore, the above can be detected. Figure 3a The experimental data provided are as follows.

[0090] The frequency range at which the piezoelectric speaker 503 in the working circuit 500A is easily triggered by overcurrent protection can be determined by analyzing the experimental data described above. For example, see the above... Figure 3a As shown, when the test signal frequency is between 1kHz and 20kHz, the current value I... L All of these values ​​are greater than the standard current value of 1.2A. At this point, the frequency range of the audio signal that is likely to trigger overcurrent protection should be from 1KHz to 20KHz.

[0091] The amplitude of the test signal within the aforementioned frequency range that is prone to triggering overcurrent protection was adjusted through experimental testing. Specifically, the amplitude of the test signal was reduced to adjust the driving voltage V supplied by the power amplifier 502 to the piezoelectric speaker 503. OUT This reduces the current I flowing from the power amplifier 502 to the piezoelectric speaker 503. L Reduce. Lower the amplitude of the audio signal until a current value I is detected. L The current reaches the value corresponding to the standard current I_max. At this point, the reduced amplitude can be recorded as the boundary amplitude corresponding to the frequency of the audio signal.

[0092] Furthermore, based on the boundary amplitudes corresponding to the frequencies of each audio signal within the frequency range easily triggering overcurrent protection as detected in the above experiments, curve fitting can be performed to obtain the frequency-boundary amplitude curve of the piezoelectric loudspeaker 503. For example, see... Figure 5b , Figure 5b The frequency-boundary amplitude curve 515 of the piezoelectric loudspeaker 503 obtained by curve fitting is shown. Understandably, when the frequency of the audio signal is less than the lower limit of the frequency range that is likely to trigger overcurrent protection, such as audio signals with a frequency range of 20Hz to 1000Hz in curve 515, the corresponding boundary amplitude of such audio signals can be a large value, for example, the maximum amplitude of 0dB.

[0093] Figure 5bThe diagram also shows the frequency-original amplitude curve 514 corresponding to the test signal. The original amplitude of the test signal with a frequency exceeding 1000Hz in curve 514 exceeds the boundary amplitude curve corresponding to the audio signal in curve 515, which may trigger overcurrent protection.

[0094] Understandably, the material composition of the piezoelectric ceramic used to make the piezoelectric element affects the standard capacitance of the piezoelectric element at room temperature (25°C), thus causing differences in the frequency-boundary amplitude curves of different piezoelectric loudspeakers. However, through experimental testing and curve fitting, the variation patterns of the frequency-boundary amplitude curves of piezoelectric elements made from piezoelectric ceramics with different material compositions are similar or consistent. For example, the standard capacitance of the piezoelectric element corresponding to curve 515 for piezoelectric loudspeaker 503 is 3.5 μF. Figure 5b The frequency-boundary amplitude curve 516 for a piezoelectric element with a standard capacitance of 4.2 μF is also shown; see [reference]. Figure 5b It can be seen that curves 515 and 516 are different, but both show the variation law that the boundary amplitude corresponding to the input audio signal gradually decreases as the frequency of the audio signal increases.

[0095] Furthermore, in some embodiments, the aforementioned frequency range that is easily triggered by overcurrent protection, determined through experimental testing, can be verified based on formula (3). For example, the following calculation formula (4) can be obtained based on formula (3), which can be based on the drive voltage value V. OUT And the capacitance value C of the piezoelectric element L Calculate the frequency of the audio signal that drives the piezoelectric speaker to produce sound:

[0096]

[0097] Therefore, based on formula (4), the lower limit of the frequency range that is likely to trigger overcurrent protection can be obtained:

[0098]

[0099] Where V_max is the maximum driving voltage supplied by the power amplifier 502 to the piezoelectric speaker 503. It is understood that the piezoelectric element of the piezoelectric speaker 503 may break down under excessively high voltage. Therefore, V_max can be determined based on the maximum withstand voltage of the piezoelectric speaker 503. When the power amplifier 502 supplies the piezoelectric speaker 503 with the driving voltage V_max used for processing the test signal... OUT When the value is greater than V_max, the piezoelectric element of the piezoelectric loudspeaker 503 will be broken down and damaged.

[0100] Furthermore, f can be calculated based on the above formula (5). piezoThe reliability of the frequency range of the audio signal that is easily triggered by overcurrent protection, obtained from experimental testing, was verified.

[0101] In some embodiments, the driving voltage value V can also be monitored during the process of determining the boundary amplitude corresponding to the frequency of the test signal through experimental testing. OUT Is it greater than the maximum withstand voltage of the piezoelectric loudspeaker 503? For example, if the amplitude of the test signal corresponds to the driving voltage value V... OUT If the voltage exceeds the maximum withstand voltage, the amplitude of the test signal is reduced to determine the boundary amplitude corresponding to the frequency of the test signal based on the maximum withstand voltage and the standard current value. Adjusting the amplitude of the input audio signal based on the frequency-boundary amplitude curve determined in this way ensures that the piezoelectric speaker 503 is not at risk of breakdown when the audio signal amplitude does not exceed its corresponding boundary amplitude, and the operating circuit 500A will not trigger overcurrent protection when processing the audio signal.

[0102] Furthermore, the frequency-amplitude adjustment parameter curve can be determined based on the aforementioned frequency-boundary amplitude curve. In some embodiments, the current value I flowing through the power amplifier 502 to the piezoelectric speaker 503 is... L Transient current fluctuations may occur due to the influence of other factors. Therefore, to avoid these transient current fluctuations exceeding the standard current value I_max and triggering overcurrent protection, the amplitude of the test signal at its frequency can be adjusted by reducing the amplitude margin of the boundary amplitude corresponding to that frequency in the frequency-boundary amplitude curve, and this adjustment parameter can be used as the amplitude adjustment parameter for that frequency. For example, the reduced amplitude margin can be 1dB to 2dB, which is not limited in this application. Furthermore, curve fitting is performed based on the frequency of each test signal and its corresponding amplitude adjustment parameter. Figure 5c The diagram shows the frequency-amplitude adjustment parameter curve corresponding to the piezoelectric speaker 503, which can be obtained through curve fitting. After adjusting the amplitude of the aforementioned test signal according to this frequency-amplitude adjustment parameter curve, the power amplifier 502 provides the piezoelectric speaker 503 with a drive voltage V for processing the test signal. OUT See the frequency-voltage curve. Figure 5d It can be seen that when processing test signals of different frequencies, the corresponding driving voltage V OUT All values ​​do not exceed the maximum withstand voltage of the piezoelectric element, which is 11V.

[0103] Understandably, because the amplitude adjustment parameter corresponding to the frequency of the audio signal in the frequency-amplitude adjustment parameter curve is close to the boundary amplitude corresponding to that frequency, the current value I flowing from the power amplifier 502 to the piezoelectric speaker 503 when processing an audio signal with an amplitude adjustment parameter is also close. LThe current can be less than and close to the standard current value I_max. At this time, the loudness of the audio signal played through the piezoelectric speaker 503 can approach the maximum loudness that the audio signal can be played based on the working circuit 500A. Therefore, this embodiment ensures that the playback loudness of the audio signal is close to its maximum loudness while effectively preventing overcurrent protection from being triggered by transient current fluctuations generated by the working circuit 500A.

[0104] In addition, researchers found that if the temperature of the piezoelectric element in the piezoelectric loudspeaker changes, it will affect the above-mentioned Figure 3a The experimental data shown has a certain impact. Analysis reveals that an increase in the temperature of the piezoelectric element leads to a decrease in its impedance. Therefore, to ensure that the above-mentioned adjustment of the audio signal amplitude can control the current in the piezoelectric speaker's operating circuit to approach the standard current value, the influence of temperature on the piezoelectric element's impedance can be further studied. This will allow for the determination of the corresponding compensation amplitude at different temperatures, thus compensating for the amplitude adjustment of the audio signal input to the piezoelectric speaker driving the speaker.

[0105] Specifically, Figure 6a According to an embodiment of this application, a temperature-capacitance variation curve of a piezoelectric element corresponding to a piezoelectric loudspeaker 503 is shown.

[0106] like Figure 6a As shown, the curve represents the change in capacitance of the piezoelectric element of the piezoelectric loudspeaker 503 at different temperatures compared to the standard capacitance value. This change can be expressed as a percentage. For example, at a temperature of 55°C, the capacitance of the piezoelectric element is 19% higher than the standard capacitance value at room temperature of 25°C. Based on the aforementioned formula (1), it can also be seen that the increase in capacitance caused by the increase in temperature will lead to a decrease in the impedance of the piezoelectric element.

[0107] Specifically, see Figure 6b As shown in the frequency-impedance curves of the piezoelectric element of the piezoelectric speaker 503 under different temperature conditions, the impedance of the piezoelectric element decreases with increasing temperature. Therefore, as the temperature of the piezoelectric element increases, its impedance decreases, which in turn increases the current I flowing from the power amplifier 502 to the piezoelectric speaker 503. L It increases. And the increased current value I L This may exceed the standard current value I_max, triggering overcurrent protection.

[0108] Since the frequency factor of the input audio signal can be avoided from triggering overcurrent protection based on the aforementioned frequency-boundary amplitude curve and / or frequency-amplitude adjustment parameter curve, the following analysis of the influence of temperature factor on triggering overcurrent protection does not consider the frequency difference of the input audio signal. Furthermore, without considering the frequency difference of the input audio signal, and combining with the aforementioned formula (3), the current value I flowing from the power amplifier 502 to the piezoelectric speaker 503 is... L The change is only affected by the change in the driving voltage value V and the capacitance value C of the piezoelectric speaker 503. L The impact of changes.

[0109] Therefore, it can be seen that the capacitance C of the piezoelectric speaker 503 increases with temperature. L The voltage will increase accordingly, at which point it is necessary to reduce the driving voltage V of the piezoelectric speaker 503 when processing the audio signal. OUT So that the current I in the working circuit is 500A L It stabilizes below the standard current.

[0110] As mentioned earlier, the larger the amplitude of the audio signal, the higher the driving voltage V required for the piezoelectric loudspeaker to process that audio signal. OUT The larger the amplitude of the audio signal, the lower the required driving voltage V corresponding to the audio signal driving the piezoelectric speaker can be in this embodiment, thereby reducing the current I in the piezoelectric speaker's operating circuit. L Maintain stability.

[0111] Therefore, based on the above conclusions, this application can determine through experimental testing the current I in the piezoelectric loudspeaker operating circuit under different temperature conditions. L The compensation amplitude is maintained at the standard overcurrent protection current value I_max. The experimental test process is explained in detail below with reference to the 500A operating circuit.

[0112] At different temperatures of the piezoelectric element in the piezoelectric loudspeaker 503, a test signal within the aforementioned frequency range that is easily triggered by overcurrent protection is input to the power amplifier 502 based on the operating circuit 500A, and the amplitude of the test signal is its corresponding boundary amplitude. In one embodiment, simulation is performed based on each test signal and the operating circuit 500A to monitor the current value I flowing from the power amplifier 502 to the piezoelectric loudspeaker 503 during the processing of each test signal. L And the drive voltage V provided by the power amplifier 502 to the piezoelectric speaker 503 for processing the test signal. OUT The amplitude of each test signal is adjusted; specifically, the amplitude of the test signal is reduced until the corresponding current value I is reached. L With driving voltage value V OUTThe decrease is adjusted to the standard current value I_max. The amplitude adjustment amount corresponding to the test signal at this time is recorded as the compensation amplitude corresponding to that temperature value. Then, curve fitting can be performed based on each temperature value and its compensation amplitude to obtain the temperature-compensation amplitude curve.

[0113] Understandably, if, under certain temperature conditions, during the process of the working circuit 500A processing the aforementioned test signal whose amplitude is its boundary amplitude, the current value I flowing through the power amplifier 502 to the piezoelectric speaker 503 is... L Since none of the currents exceed the standard current value I_max, the experimental determination process for the temperature compensation amplitude is unnecessary. Accordingly, this temperature can be used as a temperature threshold. When the temperature of the piezoelectric element is greater than this temperature threshold, the temperature of the piezoelectric element belongs to the first temperature range. At this time, the amplitude of the input audio signal can be adjusted based on the aforementioned compensation amplitude.

[0114] In another embodiment for determining the temperature-compensation amplitude curve, the difference from the above embodiment is that the piezoelectric temperature can be determined by the piezoelectric capacitance value, thereby determining the temperature-compensation amplitude curve. See also Figure 6c The temperature-capacitance curves 601, 602, and 603 for a piezoelectric element with a standard capacitance of 4 μF all exhibit a linear relationship. Therefore, a relationship between temperature T and capacitance C can be constructed. L The linear equation (6):

[0115] C L =a1T+b1(6)

[0116] Within the operating temperature range of a piezoelectric loudspeaker, for example, -20°C to 55°C, the change in piezoelectric capacitance due to temperature is relatively small, for example, -20% to 20%. For a piezoelectric element with a standard capacitance of 3.5 μF, this capacitance change ranges from 2.8 μF to 4.2 μF. Within this relatively small capacitance change range, the capacitance C of the piezoelectric element... L and impedance Z L It can also be approximated as a linear relationship; therefore, an impedance Z can be constructed. L and capacitor C L The linear equation (7):

[0117] Z L =a2C L +b2(7)

[0118] Referring to the aforementioned formula (2), we can see that:

[0119] V OUT =I L ·ZL (8)

[0120] Furthermore, based on linear equations (6) and (7), a linear equation (9) relating the driving voltage V to the temperature T can be constructed:

[0121] V OUT =I L ·(a2C L +b2)

[0122] =I L ·(a2(a1T+b1)+b2)

[0123] =I L a2a1T+I L a2b1+I L b2

[0124] =a3T+b3(9)

[0125] Where, a3 = I L a2a1, b3 = I L a2b1+I L b2.

[0126] Therefore, based on the amplitude of the input audio signal and the driving voltage V OUT The linear relationship shows that there is also a linear relationship between the amplitude of the audio signal input to the piezoelectric loudspeaker and the temperature of the piezoelectric element of the loudspeaker.

[0127] Furthermore, in the aforementioned process of determining the compensation amplitude corresponding to the temperature value, only the correspondence between two sets of temperature values ​​and compensation amplitudes needs to be determined. A linear equation can then be constructed based on these two sets of correspondences, and the temperature-compensation amplitude curve can be determined based on this linear equation. For example, in the aforementioned process of determining the compensation amplitude corresponding to the temperature value, it is determined that the compensation amplitude of the audio signal is -0.2dB at a temperature of 45℃ and -1dB at a temperature of 55℃. Therefore, a compensation amplitude A can be constructed based on (55℃, -1dB) and (45℃, -0.2dB). T And the linear equation for temperature T: A T = -0.08T + 3.4. Furthermore, see... Figure 6d The curve corresponding to the linear equation is used as the temperature-compensation amplitude curve.

[0128] Understandably, based on the aforementioned frequency-amplitude adjustment parameter curve and temperature-compensation amplitude curve, the amplitude of the input audio signal is first adjusted based on its frequency and frequency-amplitude adjustment parameter curve to avoid overcurrent protection caused by frequency factors; then, the amplitude of the audio signal is further adjusted based on the temperature of the piezoelectric element and temperature-compensation amplitude curve to avoid overcurrent protection caused by temperature factors.

[0129] Ultimately, it can be constructed as follows Figure 5c The frequency-amplitude adjustment parameter curve shown and as follows Figure 6d The temperature-compensation amplitude curve is shown. The operating circuit of the piezoelectric speaker of the mobile phone 100 can implement an audio processing method based on the aforementioned frequency-amplitude adjustment parameter curve and temperature-compensation amplitude curve. For example, a digital processing module can be provided in the operating circuit of the piezoelectric speaker of the mobile phone 100. This module can execute the audio processing method provided in this application based on the aforementioned frequency-amplitude adjustment parameter curve and temperature-compensation amplitude curve, and perform amplitude adjustment processing on the audio signal to be processed. This digital processing module can refer to the following... Figure 7a The digital processing module 702 shown below can be referred to for details, which will not be repeated here.

[0130] Figure 7a A schematic diagram of an audio processing circuit for implementing the audio processing method provided in this application is shown according to an embodiment of this application.

[0131] The following is combined with Figure 7a The specific structure of the piezoelectric speaker operating circuit 700A of the mobile phone 100, which is capable of implementing the aforementioned audio processing method based on the aforementioned frequency-amplitude adjustment parameter curve and temperature-compensation amplitude curve, is described in detail.

[0132] like Figure 7a As shown, the operating circuit 700A of the piezoelectric speaker in mobile phone 100 may include a power supply 701, a digital processing module 702, a power amplifier 703, a piezoelectric speaker 704, and a filter 705. The digital processing module 702 may include a curve filter 702a, a temperature compensation module 702b, a capacitance detection module 702c, an anomaly detection module 702d, a pilot modulation module 702e, and a limiter 702f. The power amplifier 703 may include a boost converter 703a, a modulator 703b, and an amplifier 703c.

[0133] The aforementioned digital processing module 702 and its included curve filter 702a, temperature compensation module 702b, capacitance detection module 702c, anomaly detection module 702d, pilot modulation module 702e, and limiter 702f can be implemented by a processor executing corresponding algorithms. The processor can be a digital signal processor (DSP), a field programmable gate array (FPGA), etc., and there are no restrictions here.

[0134] Specifically, the curve filter 702a can be used to receive the audio signal to be played from the mobile phone 100 and adjust the amplitude of the audio signal based on the aforementioned frequency-amplitude adjustment parameter curve. For the sake of clarity, the specific implementation process of adjusting the amplitude of the audio signal based on the frequency-amplitude adjustment parameter curve will be described in detail below, and will not be repeated here.

[0135] The temperature compensation module 702b can be used to receive the audio signal after amplitude adjustment by the curve filter 702a, and further adjust the amplitude of the audio signal based on the aforementioned temperature-compensation amplitude curve. For the sake of clarity, the specific implementation process of further adjusting the amplitude of the audio signal based on the temperature-compensation amplitude curve will be described in detail below, and will not be repeated here.

[0136] The pilot modulation module 702e may include a pilot signal, which can be used to mix the audio signal output by the temperature compensation module 702b with the pilot signal. Here, the pilot signal can be a single-frequency signal with a low amplitude to reduce the impact of the pilot signal's high playback volume on the playback effect. For example, the pilot signal can be a 6kHz, -35dB single-frequency signal. Furthermore, to avoid the pilot signal affecting the playback effect, the frequency of the pilot signal can be set in a high-frequency range inaudible to the human ear; for example, the pilot signal can be a 30kHz, -35dB single-frequency signal. No limiting descriptions are made regarding the parameters of the pilot signal here.

[0137] Limiter 702f can be used to receive the mixed audio signal from pilot modulation module 702e and verify the amplitude of the audio signal V4 to ensure that overcurrent protection is not triggered when the audio signal is played. In one exemplary embodiment, limiter 702f can be used to determine whether the amplitude of the audio signal exceeds the amplitude adjustment parameter or boundary amplitude corresponding to its frequency. If the amplitude of the audio signal exceeds the amplitude adjustment parameter or boundary amplitude corresponding to its frequency, its amplitude can be adjusted to the corresponding amplitude adjustment parameter or boundary amplitude.

[0138] Power amplifier 703 amplifies the audio signal sent by limiter 702f and provides the drive voltage required for processing the audio signal to piezoelectric speaker 704. Specifically, boost converter 703a in power amplifier 703 can be used to convert the supply voltage V provided by power supply 701 into a boost converter voltage. BAT Amplified to boost voltage V BST And based on the boost voltage V BST The piezoelectric loudspeaker 704 is supplied with the drive voltage V required to process audio signals. OUT The amplifier 703c in the power amplifier 703 can be based on the boost voltage V. BST The audio signal sent by the limiter 702f is amplified. The modulator 703b in the power amplifier 703 may include an overcurrent protection circuit, a current feedback circuit, and a voltage feedback circuit. The overcurrent protection circuit limits the current I flowing through the power amplifier 703 to the piezoelectric speaker 704. L The current value I_max that triggers overcurrent protection shall not exceed the standard current value. The current feedback circuit and voltage feedback circuit can extract the drive voltage V based on the pilot signal in the audio signal. OUT and current I L The numerical information. Among them, modulator 703b can be a Class D amplifier modulator 703b, and no specific restriction is made on the specific type of modulator 703b here.

[0139] The capacitance detection module 702c is used to receive the drive voltage V from the modulator 703b. OUT and current I L The numerical information, and based on the driving voltage V OUT and current I L The numerical information determines the capacitance C of the piezoelectric loudspeaker 704 at this time. L .

[0140] Specifically, the capacitance detection module 702c can first be based on the drive voltage V OUT and current I L The numerical information is used to calculate the piezoelectric impedance Z of the piezoelectric loudspeaker 704. L Therefore, based on impedance Z L Calculate the piezoelectric capacitance C of the piezoelectric loudspeaker 704. L .

[0141] In a driving voltage V OUT and current I L The numerical information is used to calculate the piezoelectric impedance Z of the piezoelectric loudspeaker 704. L In this implementation, the capacitance detection module 702c can detect several sets of driving voltages V received. OUT and current I LThe numerical information is smoothed for calculation, and the smoothed current value I is calculated based on the smoothed current value. rms and smoothed voltage value V rms Calculate the impedance value Z L To avoid random noise that may exist in the current feedback circuit and voltage feedback circuit affecting the drive voltage V OUT and current I L The accuracy of the numerical information is affected. This, in turn, can improve the impedance value Z. L The accuracy of the calculation results is ensured. The specific process is as follows:

[0142]

[0143]

[0144]

[0145] Among them, I1 to I n For a current feedback circuit, n current values ​​I are determined based on n pilot signals, with the DC component removed. L ;I rms To smooth the calculated smooth current; U1 to U n The current feedback circuit uses n pilot signals to determine n drive voltage values ​​V after removing the DC component. OUT ;U rms The smoothed voltage obtained from the smoothing calculation; Z rms For smooth current I rms and smoothing voltage U rms The impedance value of the piezoelectric loudspeaker 704 is calculated. This calculation process can be implemented based on a smart power amplifier (Smart PA) algorithm. Furthermore, the capacitance detection module 702c is based on impedance Z. L Calculate the piezoelectric capacitance C of the piezoelectric loudspeaker 704. L .

[0146] The anomaly detection module 702d can detect the current I received from the power amplifier 703. L The numerical information and the piezoelectric capacitance value C sent by the capacitance detection module 702c L Anomaly detection is performed based on the numerical information. Specifically, it can be based on the piezoelectric capacitance value C. L The piezoelectric capacitance threshold is used to determine whether the piezoelectric element of the piezoelectric speaker 704 is at risk of damage and / or breakage. This can be determined based on the current I. L The open circuit current threshold and / or open circuit current threshold are used to determine whether the piezoelectric loudspeaker 704 is at risk of short circuit or open circuit.

[0147] For example, see Figure 8When it is determined that there is a risk of damage and / or breakage of the piezoelectric element and / or a risk of short circuit or open circuit, a command can be sent to the power amplifier 703 to stop the transmission of the audio signal, so as to shut down audio playback or switch the audio playback channel, such as using a backup speaker for audio playback. When the capacitance of the piezoelectric element is abnormally high, the working circuit can be instructed to further reduce the amplitude of the audio signal. In one embodiment, the anomaly detection module 702d can send a command to the curve filter 702a, so that the curve filter 702a, when processing the input audio signal, performs another amplitude reduction based on the frequency-amplitude adjustment parameter curve. At this time, the amplitude reduction amount can be a fixed amount or a variable, which is not limited here. In other embodiments, a command can also be sent to the temperature compensation module 702b, so that the temperature compensation module 702b, when processing the audio signal, performs another amplitude reduction based on the temperature-compensation amplitude curve. The anomaly detection module 702d can also report the aforementioned anomalies.

[0148] Furthermore, if the anomaly detection module 702d detects no anomalies, it can send a command to the power amplifier 703, causing the power amplifier 703 to send the amplified audio signal to the filter 705. Here, the commands sent by the anomaly detection module 702d to the power amplifier 703, the curve filter 702a, and / or the temperature compensation module 702b can be I2C commands sent via the I2C interface. No specific restrictions are placed on the type of commands sent by the anomaly detection module 702d.

[0149] The filter 705 can be used to receive the amplified audio signal output from the power amplifier 703, convert it into an analog signal, and then output it to the piezoelectric speaker 704.

[0150] The piezoelectric loudspeaker 704 is used to play audio signals in the form of received analog signals.

[0151] In one exemplary embodiment, the aforementioned curve filter 702a can be implemented based on an advanced biquad filter in a DSP. Specifically, the difference equation of the curve filter 702a implemented based on the advanced biquad filter is expressed as the following calculation formula (13):

[0152] Y(n)=a0X(n)+a1X(n-1)+a2X(n-2)-b1Y(n-1)-b2Y(n-2) (13)

[0153] Performing a z-transform on the above formula (7) yields:

[0154] Y(z)=b1Y(z)z -1 +b2Y(z)z -2= a0X(z) + a1X(z) -1 +a2X(z)z -2 (14)

[0155] According to equation (7):

[0156] Y(z)[1+b1z -1 +b2z -2 ]=X(z)[a0+a1z -1 +a2z -2 (15)

[0157] According to equation (9), the transfer function of the curve filter 702a in the z-domain is expressed as follows:

[0158]

[0159] Where b1, b2, a0, a1, and a2 are the parameters of the curve filter 702a, X(z) is the z-transform of the audio signal input to the curve filter 702a, and Y(z) is the z-transform of the audio signal output to the curve filter 702a.

[0160] Furthermore, the parameters b1, b2, a0, a1, and a2 of the curve filter 702a can be adaptively designed based on the frequency-amplitude adjustment parameter curve, thereby determining the transfer function of the curve filter 702a. This ensures that after the curve filter 702a processes the audio signal that can trigger overcurrent protection based on its transfer function, the amplitude of the audio signal is the amplitude adjustment parameter corresponding to its frequency in the frequency-amplitude adjustment parameter curve.

[0161] In some embodiments, after designing parameters b1, b2, a0, a1, a2 of the curve filter 702a, a verification signal can be input to the curve filter 702a. For example, the verification signal can be a single-frequency signal and / or a frequency sweep signal with an amplitude of 0dB, to ensure that after the audio signal to be played by the mobile phone 100 is processed based on the curve filter 702a, the audio signal will not trigger overcurrent protection.

[0162] It is understandable that the above Figure 7a The piezoelectric speaker operating circuit 700A shown can be installed in the aforementioned mobile phone 100 or tablet computer, desktop, laptop, handheld computer, netbook, as well as augmented reality / virtual reality devices, smart TVs, smartwatches and other wearable devices, in-vehicle devices, portable game consoles, portable music players, televisions and other electronic devices that use piezoelectric speakers as sound-generating devices.

[0163] Figure 7b An implementation flowchart of an audio processing method is shown according to an embodiment of this application. It can be understood that... Figure 7bThe execution subject of each step in the illustrated process can be an electronic device such as the aforementioned mobile phone 100. For ease of description, the following description of each step will use the mobile phone 100 as the execution subject. For a specific exemplary structure of the mobile phone 100, please refer to the following text. Figure 9 The descriptions and related information shown will not be repeated here.

[0164] Specifically, the implementation process includes the following steps:

[0165] 711: Obtain the frequency of the first audio signal to be processed.

[0166] 712: Determine that the frequency of the first audio signal is within the frequency range of the aforementioned easily triggered overcurrent protection.

[0167] 713: Adjust the amplitude of the first audio signal based on the amplitude adjustment parameter corresponding to the frequency of the first audio signal to obtain the third audio signal.

[0168] For example, when an audio file in mobile phone 100 needs to be played, the first audio signal of the audio file can be input to the above-mentioned... Figure 7b The curve filter 702a in the middle is used to perform the aforementioned steps 711 to 713. Specifically, the transfer function of the curve filter 702a is determined based on the aforementioned frequency-amplitude adjustment parameter curve, and the amplitude of the input first audio signal can be adjusted based on the frequency-amplitude adjustment parameter curve to obtain the third audio signal.

[0169] For example, when the frequency of the input first audio signal is not within the frequency range of the aforementioned easily triggered overcurrent protection, the amplitude adjustment parameter corresponding to that frequency in the aforementioned frequency-amplitude adjustment parameter curve can be the maximum amplitude of 0dB. In this case, the amplitude of the first audio signal does not exceed its corresponding amplitude adjustment parameter. Therefore, the curve filter 702a, based on its transfer function, does not need to adjust the amplitude of the first audio signal and directly outputs the first audio signal as the third audio signal. When the frequency of the input first audio signal is within the frequency range of the aforementioned easily triggered overcurrent protection, the curve filter 702a, based on its transfer function, can lower the amplitude of the first audio signal to the amplitude adjustment parameter corresponding to its frequency in the frequency-amplitude adjustment parameter curve to obtain the third audio signal. It can be understood that when the amplitude of the first audio signal within the aforementioned easily triggered overcurrent protection frequency range does not exceed its corresponding amplitude adjustment parameter, the amplitude of the first audio signal does not need to be adjusted, and the first audio signal is directly output as the third audio signal.

[0170] 714: The amplitude of the third audio signal is adjusted based on the temperature information and the corresponding compensation amplitude to obtain the second audio signal.

[0171] In one embodiment, the temperature of the piezoelectric element of the piezoelectric speaker 704 can be measured, for example, by a temperature sensor, and this temperature information is sent to the temperature compensation module 702b. The temperature compensation module 702b receives the third audio signal sent by the curve filter 702a and adjusts the amplitude of the third audio signal according to the aforementioned temperature information and the compensation amplitude corresponding to that temperature in the temperature-compensation amplitude curve to obtain a second audio signal. For example, if the temperature information is 55°C, and its corresponding compensation amplitude in the temperature-compensation amplitude curve is -1dB, then the amplitude of the received second audio signal is reduced by -1dB. Understandably, here, the temperature value of the piezoelectric element of the piezoelectric speaker 704 can be compared with a temperature threshold. If the temperature value is greater than the temperature threshold and belongs to a first temperature range, then the amplitude of the third audio signal can be adjusted based on the temperature value and the compensation amplitude corresponding to that temperature in the temperature-compensation amplitude curve to obtain the second audio signal.

[0172] In another embodiment, when the capacitance value of the piezoelectric element of the piezoelectric speaker 704 exhibits a linear relationship with its temperature value, the temperature compensation module 702b can determine the temperature information of the piezoelectric element based on its capacitance value. Then, based on this temperature information and its corresponding compensation amplitude in the temperature-compensation amplitude curve, the module adjusts the amplitude of the third audio signal to obtain the second audio signal. The specific implementation process of the temperature compensation module 702b obtaining the capacitance value of the piezoelectric element of the piezoelectric speaker 704 will be described below and will not be repeated here.

[0173] 715: Determine whether there is an abnormality in the working circuit of the piezoelectric speaker based on the second audio signal.

[0174] If the result is negative, it indicates that there is no abnormality in the detection. Then proceed to step 716 below.

[0175] If the judgment result is yes, it indicates that there is an abnormality in the detection, then proceed to step 717 below.

[0176] In an example method for anomaly detection based on a second audio signal, the specific process is as follows:

[0177] The pilot modulation module 702e can receive the second audio signal sent by the temperature compensation module 702b, and perform a mixing operation between the second audio signal and the pilot signal to obtain a fourth audio signal. Here, the pilot signal can be pre-stored in the pilot modulation module 702e. Furthermore, the pilot modulation module 702e can also send the fourth audio signal to the limiter 702f so that the limiter 702f can verify the amplitude of the fourth audio signal.

[0178] The power amplifier 703 can receive the fourth audio signal sent by the pilot modulation module 702e, and can extract the driving voltage V based on the pilot signal of the fourth audio signal. OUT and current I L Numerical information.

[0179] The capacitance detection module 702c can receive the drive voltage V sent by the power amplifier 703. OUT and current I L The numerical information, and based on the driving voltage V OUT and current I L The numerical information determines the capacitance C of the piezoelectric element of the piezoelectric loudspeaker 704 at this time. L Here, the capacitance detection module 702c can also detect the capacitance C of the piezoelectric element of the piezoelectric speaker 704. L Send to temperature compensation module 702b so that temperature compensation module 702b can use the capacitor C L The temperature information of the piezoelectric element is determined, thereby adjusting the amplitude of the subsequently received audio signal.

[0180] The anomaly detection module 702d can receive the current I sent by the power amplifier 703. L The numerical information and the piezoelectric capacitance value C sent by the capacitance detection module 702c L Numerical information, and then based on the current I L and the capacitance value C of the piezoelectric element L Anomaly detection was performed on the operating circuit of the piezoelectric loudspeaker 704.

[0181] The specific operations performed by the pilot modulation module 702e, limiter 702f, power amplifier 703, capacitor detection module 702c, and anomaly detection module 702d are detailed in the preceding text. Figure 7a The detailed explanation is omitted here.

[0182] 716: Drives the piezoelectric speaker 704 to play the second audio signal.

[0183] In one exemplary embodiment, a piezoelectric speaker 704 can be driven to play a fourth audio signal resulting from the mixing of a second audio signal and a pilot signal. When the anomaly detection module 702d determines that the operating circuit of the piezoelectric speaker 704 is normal, it can send a command to the power amplifier 703. Upon receiving the command, the power amplifier 703 can send the amplified fourth audio signal to the filter 705. The filter 705 can convert the received fourth audio signal into an analog signal. The piezoelectric speaker 704 can receive the fourth audio signal in analog form sent by the filter 705 and play it. Here, the reason why the pilot signal does not affect the playback effect is explained above. Figure 7aThe detailed explanation is omitted here.

[0184] For details regarding the operations performed by the power amplifier 703, filter 705, and piezoelectric speaker 704, please refer to the preceding text. Figure 7a The detailed explanation is omitted here.

[0185] 717: Exception handling.

[0186] In one exemplary embodiment, when the anomaly detection module 702d determines that there is an anomaly in the operating circuit of the piezoelectric speaker 704, it can report the anomaly and / or address the anomaly based on... Figure 8 The corresponding processing should be performed as shown. For details on the anomaly reporting and processing operations of the anomaly detection module 702d, please refer to the previous section on... Figure 7a The detailed explanation is omitted here.

[0187] Here, based on the aforementioned implementation process, the current of the piezoelectric speaker 704 in the mobile phone 100 when processing audio signals is suppressed to a standard current value that is less than and close to the overcurrent protection limit. Therefore, audio signals that would otherwise be unable to be played due to overcurrent protection can be played at a volume close to the maximum loudness that the piezoelectric speaker can play. Other audio signals that do not trigger overcurrent protection due to lower frequency and / or smaller amplitude are played through the piezoelectric speaker at their original loudness. Therefore, without triggering overcurrent protection, the loudness of the audio signal output can be maximized, thereby maximizing the SPL performance of the piezoelectric speaker 704.

[0188] See Figure 7c The audio signal playback loudness comparison chart shown indicates that audio signals above 1kHz would normally be unable to play due to overcurrent protection being triggered because their frequency reaches the range where overcurrent protection is easily triggered, and their amplitude is also large. The loudness curve of audio signals above 1kHz played based on the aforementioned technical solution of connecting a high-power resistor in series in the operating circuit of the piezoelectric speaker 704 is shown in curve 720b, and the loudness curve of audio signals above 1kHz played based on steps 701 to 706 is shown in curve 720a.

[0189] Comparing curves 720a and 720b, it can be seen that in curve 720b, the playback loudness of audio signals above 1kHz is generally suppressed, and it differs significantly from the maximum playback loudness of the piezoelectric speaker 704 (112dB). Although overcurrent protection is avoided, the SPL performance of the piezoelectric speaker 704 is not fully utilized. In contrast, in curve 720a, the playback loudness of audio signals above 1kHz is close to the maximum playback loudness of the piezoelectric speaker 704 (112dB). This avoids overcurrent protection while maximizing the SPL performance of the piezoelectric speaker 704.

[0190] Furthermore, in environments with varying temperatures, the audio processing method described above can also maximize the loudness of the audio signal output and maximize the sound pressure level (SPL) performance of the piezoelectric loudspeaker 704 without triggering overcurrent protection.

[0191] Figure 9 A schematic diagram of the structure of a mobile phone 100 is shown according to an embodiment of this application.

[0192] Mobile phone 100 may include processor 110, external memory interface 120, internal memory 121, universal serial bus (USB) interface 130, charging management module 140, power management module 141, battery 142, antenna 1, antenna 2, mobile communication module 150, wireless communication module 160, audio module 170, speaker 170A, receiver 170B, microphone 170C, headphone jack 170D, sensor module 180, buttons 190, motor 191, indicator 192, camera 193, display screen 194, and subscriber identification module (SIM) card interface 195, etc. The sensor module 180 may include a pressure sensor 180A, a gyroscope sensor 180B, a barometric pressure sensor 180C, a magnetic sensor 180D, an accelerometer sensor 180E, a distance sensor 180F, a proximity sensor 180G, a fingerprint sensor 180H, a temperature sensor 180J, a touch sensor 180K, an ambient light sensor 180L, a bone conduction sensor 180M, etc.

[0193] It is understood that the structures illustrated in the embodiments of the present invention do not constitute a specific limitation on the mobile phone 100. In other embodiments of this application, the mobile phone 100 may include more or fewer components than illustrated, or combine some components, or split some components, or have different component arrangements. The illustrated components may be implemented in hardware, software, or a combination of software and hardware.

[0194] Processor 110 may include one or more processing units, such as application processors (APs), modem processors, graphics processing units (GPUs), image signal processors (ISPs), controllers, video codecs, digital signal processors (DSPs), baseband processors, and / or neural network processing units (NPUs). These different processing units may be independent devices or integrated into one or more processors.

[0195] The controller can generate operation control signals based on the instruction opcode and timing signals to complete the control of instruction fetching and execution.

[0196] The processor 110 may also include a memory for storing instructions and data. In some embodiments, the memory in the processor 110 is a cache memory. This memory can store instructions or data that the processor 110 has just used or that are used repeatedly. If the processor 110 needs to use the instruction or data again, it can retrieve it directly from the aforementioned memory. This avoids repeated accesses, reduces the waiting time of the processor 110, and thus improves the efficiency of the system.

[0197] In some embodiments, the processor 110 may include one or more interfaces. Interfaces may include an inter-integrated circuit (I2C) interface, an inter-integrated circuit sound (I2S) interface, a pulse code modulation (PCM) interface, a universal asynchronous receiver / transmitter (UART) interface, a mobile industry processor interface (MIPI), a general-purpose input / output (GPIO) interface, a subscriber identity module (SIM) interface, and / or a universal serial bus (USB) interface, etc.

[0198] The I2C interface is a bidirectional synchronous serial bus, including a serial data line (SDA) and a serial clock line (SCL). In some embodiments, the processor 110 may include multiple I2C buses. In this application embodiment, instruction interaction between the anomaly detection module 702d and modules such as the power amplifier 703 can be performed based on the I2C interface.

[0199] The processor 110 can couple to the touch sensor 180K, charger, flash, camera 193, etc., through different I2C bus interfaces. For example, the processor 110 can couple to the touch sensor 180K through the I2C interface, enabling the processor 110 and the touch sensor 180K to communicate through the I2C bus interface, thus realizing the touch function of the mobile phone 100.

[0200] USB port 130 is a USB standard compliant interface, which can be a Mini USB port, Micro USB port, USB Type-C port, etc. USB port 130 can be used to connect a charger to charge mobile phone 100, and can also be used for data transfer between mobile phone 100 and peripheral devices. It can also be used to connect headphones for audio playback. This interface can also be used to connect other electronic devices, such as AR devices.

[0201] It is understood that the interface connection relationships between the modules illustrated in the embodiments of the present invention are merely illustrative and do not constitute a structural limitation on the mobile phone 100. In other embodiments of this application, the mobile phone 100 may also adopt different interface connection methods or combinations of multiple interface connection methods as described in the above embodiments.

[0202] The charging management module 140 receives charging input from a charger. The charger can be a wireless charger or a wired charger. In some wired charging embodiments, the charging management module 140 receives charging input from the wired charger via the USB interface 130. In some wireless charging embodiments, the charging management module 140 receives wireless charging input via the wireless charging coil of the mobile phone 100. While charging the battery 142, the charging management module 140 can also supply power to the electronic device via the power management module 141.

[0203] The power management module 141 connects the battery 142, the charging management module 140, and the processor 110. The power management module 141 receives input from the battery 142 and / or the charging management module 140, providing power to the processor 110, internal memory 121, display screen 194, camera 193, and wireless communication module 160, etc. The power management module 141 can also monitor parameters such as battery capacity, battery cycle count, and battery health status (leakage current, impedance). In some other embodiments, the power management module 141 may also be located within the processor 110. In other embodiments, the power management module 141 and the charging management module 140 may be located in the same device.

[0204] The modem processor may include a modulator and a demodulator. The modulator modulates the low-frequency baseband signal to be transmitted into a mid-to-high frequency signal. The demodulator demodulates the received electromagnetic wave signal into a low-frequency baseband signal. The demodulator then transmits the demodulated low-frequency baseband signal to the baseband processor for processing. After processing by the baseband processor, the low-frequency baseband signal is transmitted to the application processor. The application processor outputs sound signals through an audio device (not limited to speaker 170A, receiver 170B, etc.) or displays images or videos through the display screen 194. In some embodiments, the modem processor may be a separate device. In other embodiments, the modem processor may be independent of the processor 110 and may be housed in the same device as the mobile communication module 150 or other functional modules.

[0205] The mobile phone 100 implements display functions through a GPU, a display screen 194, and an application processor. The GPU is a microprocessor for image processing, connected to the display screen 194 and the application processor. The GPU is used to perform mathematical and geometric calculations and for graphics rendering. The processor 110 may include one or more GPUs, which execute program instructions to generate or modify display information.

[0206] The display screen 194 is used to display images, videos, etc. The display screen 194 includes a display panel. The display panel can be a liquid crystal display (LCD), an organic light-emitting diode (OLED), an active-matrix organic light-emitting diode (AMOLED), a flexible light-emitting diode (FLED), a Mini-LED, a Micro-LED, a Micro-OLED, a quantum dot light-emitting diode (QLED), etc. In some embodiments, the mobile phone 100 may include one or N displays 194, where N is a positive integer greater than 1.

[0207] A digital signal processor (DSP) is used to process digital signals. Besides digital image signals, it can also process other digital signals. For example, when a mobile phone 100 is selecting a frequency, the DSP performs Fourier transforms on the frequency energy.

[0208] The external storage interface 120 can be used to connect an external storage card, such as a Micro SD card, to expand the storage capacity of the mobile phone 100. The external storage card communicates with the processor 110 through the external storage interface 120 to perform data storage functions. For example, music, video, and other files can be saved on the external storage card.

[0209] Internal memory 121 can be used to store computer executable program code, including instructions. Internal memory 121 may include a program storage area and a data storage area. The program storage area may store the operating system, applications required for at least one function (such as sound playback, image playback, etc.), etc. The data storage area may store data created during the use of mobile phone 100 (such as audio data, phonebook, etc.). Furthermore, internal memory 121 may include high-speed random access memory, and may also include non-volatile memory, such as at least one disk storage device, flash memory device, universal flash storage (UFS), etc. Processor 110 executes various functional applications and data processing of mobile phone 100 by running instructions stored in internal memory 121 and / or instructions stored in memory located in the processor.

[0210] The mobile phone 100 can achieve audio functions such as music playback and recording through the audio module 170, speaker 170A, receiver 170B, microphone 170C, headphone jack 170D, and application processor.

[0211] The audio module 170 is used to convert digital audio information into analog audio signals for output, and also to convert analog audio input into digital audio signals. The audio module 170 can also be used for encoding and decoding audio signals. In some embodiments, the audio module 170 may be located in the processor 110, or some functional modules of the audio module 170 may be located in the processor 110. In this embodiment, the audio module 170 may include a filter 705.

[0212] The speaker 170A, also known as a "loudspeaker," is used to convert audio electrical signals into sound signals. The mobile phone 100 can listen to music or make hands-free calls through the speaker 170A. In this embodiment, the speaker 170A may be a piezoelectric speaker 704.

[0213] The receiver 170B, also known as the "earpiece," is used to convert audio electrical signals into sound signals. When the mobile phone 100 answers a call or voice message, the receiver 170B can be brought close to the user's ear to listen to the voice.

[0214] Microphone 170C, also known as a "microphone" or "voice transducer," is used to convert sound signals into electrical signals. When making a phone call or sending a voice message, the user can speak by bringing their mouth close to microphone 170C, inputting the sound signal into microphone 170C. Mobile phone 100 may have at least one microphone 170C. In some embodiments, mobile phone 100 may have two microphones 170C, which, in addition to collecting sound signals, can also perform noise reduction. In other embodiments, mobile phone 100 may also have three, four, or more microphones 170C, which can collect sound signals, reduce noise, identify the sound source, and perform directional recording, etc.

[0215] The 170D headphone jack is used to connect wired headphones. The 170D headphone jack can be a USB 130 interface or a 3.5mm Open Mobile Terminal Platform (OMTP) standard interface, a CTIA (Cellular Telecommunications Industry Association of the USA) standard interface.

[0216] Temperature sensor 180J is used to detect temperature. In some embodiments, mobile phone 100 uses the temperature detected by temperature sensor 180J to execute a temperature processing strategy. For example, when the temperature reported by temperature sensor 180J exceeds a threshold, mobile phone 100 reduces the performance of the processor located near temperature sensor 180J to reduce power consumption and implement thermal protection. In other embodiments, when the temperature is below another threshold, mobile phone 100 heats battery 142 to prevent abnormal shutdown of mobile phone 100 due to low temperature. In still other embodiments, when the temperature is below yet another threshold, mobile phone 100 boosts the output voltage of battery 142 to prevent abnormal shutdown caused by low temperature. In embodiments of this application, temperature sensor 180J can be used to detect the temperature of the piezoelectric element of piezoelectric speaker 804.

[0217] Touch sensor 180K, also known as a "touch device," can be located on display screen 194. The touch sensor 180K and display screen 194 together form a touchscreen, also known as a "touchscreen." Touch sensor 180K detects touch operations applied to or near it. The touch sensor can transmit the detected touch operation to the application processor to determine the type of touch event. Visual output related to the touch operation can be provided through display screen 194. In other embodiments, touch sensor 180K may also be located on the surface of mobile phone 100, in a different position than display screen 194.

[0218] The bone conduction sensor 180M can acquire vibration signals. In some embodiments, the bone conduction sensor 180M can acquire vibration signals from the vibrating bone segments of the human vocal cords. The bone conduction sensor 180M can also contact the human pulse to receive blood pressure signals. In some embodiments, the bone conduction sensor 180M can also be incorporated into headphones to form bone conduction headphones. The audio module 170 can parse the voice signals from the vibrating bone segments of the vocal cords acquired by the bone conduction sensor 180M to realize voice functionality. The application processor can parse heart rate information from the blood pressure signals acquired by the bone conduction sensor 180M to realize heart rate detection functionality.

[0219] Keypad 190 includes a power button, volume buttons, etc. Keypad 190 can be a mechanical keypad or a touch keypad. Mobile phone 100 can receive keypad input and generate key signal inputs related to user settings and function control of mobile phone 100.

[0220] Motor 191 can generate vibration alerts. Motor 191 can be used for incoming call vibration alerts or for touch vibration feedback. For example, different vibration feedback effects can correspond to touch operations performed on different applications (such as taking photos, playing audio, etc.). Motor 191 can also correspond to different vibration feedback effects for touch operations performed on different areas of the display screen 194. Different application scenarios (such as time reminders, receiving messages, alarm clocks, games, etc.) can also correspond to different vibration feedback effects. The touch vibration feedback effect can also be customized.

[0221] Indicator 192 can be an indicator light, used to indicate charging status, power changes, or to indicate messages, missed calls, notifications, etc.

[0222] The SIM card interface 195 is used to connect a SIM card. The SIM card can be inserted into or removed from the SIM card interface 195 to make contact with and separate from the mobile phone 100. The mobile phone 100 can support one or N SIM card interfaces, where N is a positive integer greater than 1. The SIM card interface 195 can support Nano SIM cards, Micro SIM cards, SIM cards, etc. Multiple cards can be inserted into the same SIM card interface 195 simultaneously. The types of these multiple cards can be the same or different. The SIM card interface 195 is also compatible with different types of SIM cards. The SIM card interface 195 is also compatible with external storage cards. The mobile phone 100 interacts with the network through the SIM card to realize functions such as calls and data communication. In some embodiments, the mobile phone 100 uses an eSIM, i.e., an embedded SIM card. The eSIM card can be embedded in the mobile phone 100 and cannot be separated from the mobile phone 100.

[0223] This application also provides a computer program product for implementing the audio processing methods provided in the above embodiments.

[0224] Various embodiments of the mechanisms disclosed in this application can be implemented in hardware, software, firmware, or combinations of these implementation methods. Embodiments of this application can be implemented as computer program modules or module code executable on a programmable system, the programmable system including at least one processor, a storage system (including volatile and non-volatile memory and / or storage elements), at least one input device, and at least one output device.

[0225] Computer program modules or module code can be applied to input instructions to perform the functions described in this application and generate output information. The output information can be applied to one or more output devices in a known manner. For the purposes of this application, the processing system includes any system having a processor such as, for example, a digital signal processor (DSP), a microcontroller, an application-specific integrated circuit (ASIC), or a microprocessor.

[0226] Module code can be implemented using a high-level modular language or an object-oriented programming language to communicate with the processing system. Assembly language or machine language can also be used to implement module code when needed. In fact, the mechanisms described in this application are not limited to any particular programming language. In either case, the language can be a compiled language or an interpreted language.

[0227] In some cases, the disclosed embodiments may be implemented in hardware, firmware, software, or any combination thereof. The disclosed embodiments may also be implemented as instructions carried or stored thereon on one or more temporary or non-temporary machine-readable (e.g., computer-readable) storage media, which may be read and executed by one or more processors. For example, the instructions may be distributed via a network or through other computer-readable media. Therefore, machine-readable media may include any mechanism for storing or transmitting information in a machine-readable (e.g., computer-readable) form, including but not limited to floppy disks, optical disks, optical discs, magneto-optical disks, read-only memory (ROM), random access memory (RAM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), magnetic cards or optical cards, flash memory, or tangible machine-readable storage for transmitting information (e.g., carrier waves, infrared signals, digital signals, etc.) using the Internet in the form of electrical, optical, acoustic, or other forms of propagated signals. Therefore, machine-readable media include any type of machine-readable medium suitable for storing or transmitting electronic instructions or information in a machine-readable (e.g., computer-readable) form.

[0228] In this specification, the reference to "an embodiment" or "an embodiment" means that a specific feature, structure, or characteristic described in connection with the embodiment is included in at least one exemplary implementation or technology disclosed according to an embodiment of this application. The appearance of the phrase "in an embodiment" in various places in the specification does not necessarily refer to the same embodiment.

[0229] The disclosure of embodiments of this application also relates to means for performing operations in text. This means may be specifically constructed for the claimed purpose or may include a general-purpose computer selectively activated or reconfigured by a computer program stored in a computer. Such a computer program may be stored on a computer-readable medium, such as, but not limited to, any type of disk, including floppy disks, optical disks, CD-ROMs, magneto-optical disks, read-only memory (ROM), random access memory (RAM), EPROM, EEPROM, magnetic or optical cards, application-specific integrated circuits (ASICs), or any type of medium suitable for storing electronic instructions, and each may be coupled to a computer system bus. Furthermore, the computer mentioned in the specification may include a single processor or may employ an architecture involving multiple processors for increased computing power.

[0230] Furthermore, the language used in this specification has been primarily chosen for readability and instructional purposes and may not have been chosen to depict or limit the disclosed subject matter. Therefore, the embodiments disclosed herein are intended to illustrate, and not limit, the scope of the concepts discussed herein.

Claims

1. An audio processing method applied to an electronic device, characterized in that, The method includes: The first frequency of the first audio signal to be processed is detected to belong to the first frequency range; Based on a first target amplitude corresponding to the first frequency, the amplitude of the first audio signal is adjusted to obtain a second audio signal, including: The piezoelectric loudspeaker's current temperature is detected to be within the first temperature range; The amplitude of the first audio signal is adjusted based on the first target amplitude corresponding to the first frequency and the first amplitude adjustment amount corresponding to the first temperature to obtain the second audio signal; The second audio signal is provided to the piezoelectric speaker to drive the piezoelectric speaker to produce sound, wherein the current generated by the second audio signal input to the piezoelectric speaker is lower than the critical current of the overcurrent protection.

2. The method according to claim 1, characterized in that, The step of adjusting the amplitude of the first audio signal based on a first target amplitude corresponding to the first frequency to obtain a second audio signal includes: If the amplitude of the first audio signal is determined to be higher than the first target amplitude, the amplitude of the first audio signal is adjusted to the first target amplitude to obtain the second audio signal.

3. The method according to claim 2, characterized in that, An audio signal with an amplitude higher than the first target amplitude within the first frequency range is input into the piezoelectric loudspeaker, and the current generated therefore is higher than the critical current.

4. The method according to claim 3, characterized in that, The step of providing the second audio signal to the piezoelectric speaker to drive the piezoelectric speaker to emit sound includes: The second audio signal is provided to the piezoelectric loudspeaker so that the piezoelectric loudspeaker outputs a first current, wherein the first current is lower than the critical current.

5. The method according to claim 4, characterized in that, Providing the second audio signal to the piezoelectric speaker so that the piezoelectric speaker outputs a first current includes: The second audio signal is provided to the piezoelectric speaker based on the first voltage, so that the piezoelectric speaker outputs a first current, wherein... The first voltage is the driving voltage required to provide the second audio signal to the piezoelectric speaker with the first impedance, and the first impedance is the impedance of the piezoelectric speaker corresponding to the first frequency.

6. The method according to claim 1, characterized in that, The step of adjusting the amplitude of the first audio signal to obtain the second audio signal based on a first target amplitude corresponding to the first frequency and a first amplitude adjustment amount corresponding to the first temperature includes: The amplitude of the first audio signal is adjusted to a second target amplitude to obtain the second audio signal, wherein the second target amplitude is the target amplitude determined after the first target amplitude is adjusted based on the first amplitude adjustment amount.

7. The method according to claim 6, characterized in that, An audio signal with an amplitude higher than the second target amplitude input into a piezoelectric speaker within the first temperature range generates a current higher than the critical current.

8. The method according to claim 7, characterized in that, Providing the second audio signal to the piezoelectric speaker includes: The second audio signal is provided to the piezoelectric speaker based on the second voltage, wherein... The second voltage is the driving voltage required to supply the second audio signal to the piezoelectric speaker with the second impedance, wherein, The second impedance is the impedance of the piezoelectric loudspeaker corresponding to the first frequency and the first temperature, wherein, The second impedance is less than the first impedance of the piezoelectric loudspeaker corresponding to the first frequency.

9. An electronic device, characterized in that, include: One or more processors; One or more memories; the one or more memories storing one or more programs, which, when executed by the one or more processors, cause the electronic device to perform the audio processing method of any one of claims 1 to 8.

10. A computer-readable storage medium, characterized in that, The storage medium stores instructions that, when executed on a computer, cause the computer to perform the audio processing method according to any one of claims 1 to 8.

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