Dynamic modulation method of class D amplifier and electronic circuit thereof

Abstract

The invention provides a dynamic modulation method of a class-D amplifier and an electronic circuit thereof, and in the dynamic modulation method of the class-D amplifier, the average duty ratio of an audio amplification signal is dynamically adjusted, so that the average duty ratio of the audio amplification signal is a proper duty ratio, the power consumption of the circuit is reduced, and the reliability of the circuit is improved. Therefore, even if the average duty ratio of the audio amplification signal is kept at a low level when no audio is input, the static power consumption is reduced, and the loss caused by the inductance ripple current is also reduced at medium and small power.

Description

Technical Field

[0001] The present invention relates to the field of electronic circuits, and in particular to a dynamic modulation method of a class D amplifier and an electronic circuit thereof. Background Art

[0002] The purpose of an audio power amplifier is to reproduce the input audio signal on the sound-generating output element, providing the required volume and power level, ensuring high power reproduction and low distortion.

[0003] Among the various types of audio power amplifiers, the Class D amplifier is a high-efficiency audio amplifier that works in a switching mode. It converts the input audio signal into a high-frequency pulse signal through pulse width modulation or pulse density modulation technology, then amplifies it through a switching element, and finally restores it to an analog audio signal through a filter. The Class D amplifier has many advantages, especially high efficiency.

[0004] However, in the PWM modulation technology of the Class D amplifier, its output signal swings around the power supply voltage of the power amplifier, so that when the Class D amplifier is not playing music, the inductor ripple current is very large, resulting in high static power consumption. In addition, when the volume of the Class D amplifier is small or medium, the swing of the output signal is limited, so that the common-mode voltage leaves too much margin for the output signal to swing, resulting in waste of power consumption.

[0005] To improve the above problems, please refer to Figure 1 The prior art provides a modulation circuit of a class D amplifier, the modulation circuit includes a signal input terminal and a common-mode voltage dynamic adjustment module, wherein the signal input terminal is used to convert the received analog audio signal into a differential audio signal Vin, and the common-mode voltage dynamic adjustment unit is used to dynamically adjust the common-mode voltage of the differential audio signal. However, since the circuit modulates the analog audio signal, its design is difficult and the circuit is relatively complex. Summary of the invention

[0006] The technical solution of the present invention provides a dynamic modulation method of a class D amplifier and an electronic circuit thereof, so as to reduce the power consumption of the circuit through a simple circuit.

[0007] According to the technical solution of the present invention, a dynamic modulation method of a class D amplifier is provided, comprising: Continuously collecting a first signal from the digital signal processing module; generating a current second signal according to the current first signal, wherein the amplitude of the current second signal is the same as the amplitude of the audio amplified signal; A current control signal is generated according to the current second signal to control an average duty cycle of the audio amplification signal.

[0008] Optionally, the acquisition location of the first signal is any location in the digital signal processing module.

[0009] Optionally, generating a current second signal according to the current first signal, wherein the amplitude of the current second signal is the same as the amplitude of the amplified audio signal, includes: Obtaining a configuration gain A, where the configuration gain A is used to characterize the product of various gains that affect the amplitude of the audio amplification signal in the process from the first signal at the corresponding collection position to the output audio amplification signal, and each collection position has a corresponding configuration gain A; A current second signal is generated according to the current first signal and the configured gain A, wherein the amplitude of the current second signal is F2=A×F1, and F1 is used to characterize the amplitude of the current first signal.

[0010] Optionally, the Class D amplifier also includes an analog amplification module, an input end of the analog amplification module is coupled to the digital signal processing module through a digital-to-analog conversion unit, an output end of the analog amplification module is used to output an audio amplification signal, and the control signal controls the duty cycle of the audio amplification signal by controlling the common mode level of the analog amplification module.

[0011] Optionally, generating a current control signal according to the current second signal to control an average duty cycle of the amplified audio signal includes: Providing a plurality of judgment thresholds, wherein the plurality of judgment thresholds correspond one to one with a plurality of duty cycles; Obtaining a first judgment threshold: if the current second signal is an initial second signal, taking one of the plurality of judgment thresholds as the first judgment threshold; if the current second signal is a changed second signal, taking the second judgment threshold formed under the previous second signal as the first judgment threshold; The amplitude of the current second signal is compared with the first judgment threshold to adjust or maintain the first judgment threshold to form a second judgment threshold under the current second signal, and a current control signal is generated to control the average duty cycle of the audio amplified signal.

[0012] Optionally, generating a current control signal according to the current second signal to control an average duty cycle of the amplified audio signal further includes: Providing a number of judgment levels corresponding to a number of judgment thresholds; Obtain the corresponding first judgment threshold according to the first judgment level: if the current second signal is the initial second signal, use the preset judgment level as the first judgment level, and the judgment threshold corresponding to the first judgment level as the first judgment threshold; if the current second signal is the changed second signal, use the second judgment level formed under the previous second signal as the first judgment level, and the judgment threshold corresponding to the second judgment level as the first judgment threshold.

[0013] Optionally, the plurality of judgment thresholds include M judgment thresholds set in ascending order, the M judgment thresholds set in ascending order correspond to M duty cycles set in ascending order, and in any two adjacent judgment thresholds, the latter judgment threshold is greater than the former judgment threshold, M is a positive integer, and the amplitude of the current second signal is compared with the first judgment threshold to adjust or maintain the first judgment threshold to form a second judgment threshold, and generate a current control signal to control the average duty cycle of the audio amplified signal, including: Set a first value to 0 and a second value to 0, wherein the first value is used to represent the number of consecutive times that the amplitude of the second signal is greater than the first judgment threshold, and the second value is used to represent the number of consecutive times that the amplitude of the second signal is less than the first judgment threshold; Compare the amplitude of the current second signal with the first judgment threshold to update the first value and the second value: if the amplitude of the current second signal is greater than the first judgment threshold, the first value is increased by 1, and the second value is cleared; if the amplitude of the current second signal is less than the first judgment threshold, the second value is increased by 1, and the first value is cleared; if the amplitude of the current second signal is equal to the first judgment threshold, the first value and the second value are both cleared; According to the first value and the second value, the second judgment threshold is formed, and a current control signal is generated: if the first value is m, the first value is cleared, a judgment threshold after the current first judgment threshold is used as the second judgment threshold, and a current control signal is generated to increase the average duty cycle of the audio amplified signal to the duty cycle corresponding to the second judgment threshold; if the second value is n, the second value is cleared, a judgment threshold before the current first judgment threshold is used as the second judgment threshold, and a current control signal is generated to reduce the average duty cycle of the audio amplified signal to the duty cycle corresponding to the second judgment threshold; if the first value is less than m and the second value is less than n, the current first judgment threshold is used as the second judgment threshold, and a current control signal is generated to keep the average duty cycle of the audio amplified signal the same as the duty cycle corresponding to the second judgment threshold, and m and n are both positive integers.

[0014] Optionally, before comparing the amplitude of the current second signal with the first judgment threshold, the method also includes: smoothing the N second signals within the first time, outputting a second smoothed signal, the amplitude of the second smoothed signal Avg = (T1 + T2 + ... + TN) / N, N is a positive integer, and TN is used to characterize the amplitude of the Nth second signal within the first time.

[0015] Optionally, before comparing the amplitude of the current second signal with the first judgment threshold, the method also includes: smoothing the current second signal, outputting a second smoothed signal, and the amplitude of the output Nth second smoothed signal Avg2 = Avg1×alpha+ TN×(1-alpha), where N is a positive integer, TN is used to characterize the amplitude of the Nth second signal, Avg1 is used to characterize the amplitude of the (N-1)th second smoothed signal, alpha is used to characterize the smoothing weight of the smoothing process, and 0<alpha<1.

[0016] According to the technical solution of the present invention, an electronic circuit is also provided for implementing the above-mentioned dynamic modulation method of the class D amplifier.

[0017] Compared with the prior art, the technical solution of the present invention has the following beneficial effects: In the dynamic modulation method of the Class D amplifier provided by the technical solution of the present invention, the average duty cycle of the audio amplification signal is dynamically adjusted to be a suitable duty cycle to reduce circuit power consumption, that is, the average duty cycle of the audio amplification signal is maintained at a low level when there is no audio input, thereby reducing static power consumption, and at low and medium power, the loss caused by the inductor ripple current is also reduced.

[0018] Furthermore, by performing data smoothing processing on the second signal input into the dynamic adjustment module, it is possible to prevent a sudden change in the average duty cycle of the subsequent audio amplified signal caused by a sudden change of the second signal in a short period of time.

[0019] In the electronic circuit provided by the technical solution of the present invention, since the digital signal collected from the digital signal processing module is a digital signal, the circuit for implementing the modulation method of the above-mentioned Class D amplifier is a digital circuit, and the digital circuit structure is simpler than the analog circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a circuit block diagram of a modulation circuit of a class D amplifier; Figure 2 is a flow chart of a dynamic modulation method of a class D amplifier provided by an embodiment of the present invention; Figure 3 The present invention provides a method for obtaining a current control signal according to a current second signal in a dynamic modulation method of a class D amplifier. Figure 1 ; Figure 4 The present invention provides a method for obtaining a current control signal according to a current second signal in a dynamic modulation method of a class D amplifier. Figure 2 ; Figure 5 It is a flowchart of a method for obtaining a corresponding first judgment threshold according to a first judgment level in a dynamic modulation method of a class D amplifier provided by another embodiment of the present invention. DETAILED DESCRIPTION

[0021] As described in the background technology, the Class D amplifier will generate a large amount of power consumption waste when no music is played or when the volume is low or medium. The solution to this problem in the prior art is to change the common mode voltage of the analog audio signal. However, since the common mode voltage dynamic adjustment module processes analog signals, its design is difficult and the circuit is complex.

[0022] In view of this, the technical solution of the present invention creatively proposes a dynamic modulation method of a class D amplifier, comprising: Continuously collecting a first signal from the digital signal processing module; generating a current second signal according to the current first signal, wherein the amplitude of the current second signal is the same as the amplitude of the audio amplification signal; and generating a current control signal according to the current second signal to control the average duty cycle of the audio amplification signal.

[0023] By dynamically adjusting the average duty cycle of the audio amplified signal, the average duty cycle of the audio amplified signal is made to be a suitable duty cycle to reduce the power consumption of the circuit, that is, the average duty cycle of the audio amplified signal is kept at a low level when there is no audio input, thereby reducing the static power consumption, and at low and medium power, the loss caused by the inductor ripple current is also reduced.

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the embodiments in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention. The terms "first", "second", "third", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described here can be implemented in an order other than those illustrated or described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0025] Figure 2 is a flow chart of a dynamic modulation method of a class D amplifier provided by an embodiment of the present invention. Figure 3 The present invention provides a method for obtaining a current control signal according to a current second signal in a dynamic modulation method of a class D amplifier. Figure 1 , Figure 4 The present invention provides a method for obtaining a current control signal according to a current second signal in a dynamic modulation method of a class D amplifier. Figure 2 .

[0026] In this embodiment, the class D amplifier includes a digital signal processing module, a digital-to-analog conversion unit, and an analog amplification module, and the class D amplifier simulates and amplifies the digital audio signal obtained in the digital signal processing module to output an audio amplification signal. The digital signal processing module is used to perform digital processing according to the input digital audio signal, and its output end is connected to the input end of the digital-to-analog conversion unit, the output end of the digital-to-analog conversion unit is connected to the input end of the analog amplification module, and the output end of the analog amplification module is used to output the audio amplification signal.

[0027] Please refer to Figure 2 , the dynamic modulation method of the class D amplifier includes: The first signal is continuously collected from the digital signal processing module.

[0028] Specifically, the first signal is a signal which is discrete in time but continuous in amplitude and is acquired at a fixed frequency in a digital signal processing module.

[0029] In this embodiment, the first signal is collected at any position in the digital signal processing module. Specifically, the digital signal processing module includes a sampling rate conversion unit, a Σ-Δ modulator, etc. Any position can be understood as any position in the digital signal processing module that generates a digital signal.

[0030] A current second signal is generated according to the current first signal, wherein the amplitude of the current second signal is the same as the amplitude of the amplified audio signal.

[0031] In this embodiment, generating the current second signal according to the current first signal may include: A configuration gain A is obtained, where the configuration gain A is used to characterize the product of various gains that affect the amplitude of the audio amplification signal in the process from the first signal at the corresponding collection position to the output audio amplification signal, and each collection position has a corresponding configuration gain A.

[0032] According to the current first signal and the configuration gain A, the current second signal is generated, and the amplitude F2 of the current second signal is F2=A×F1, and F1 is used to characterize the amplitude of the current first signal. The amplitude F2 of the second signal will change accordingly with the amplitude F1 of the corresponding first signal, and the second signal is also a signal with discrete time but continuous amplitude.

[0033] In one embodiment, if the first signal acquisition position is close to the input end of the digital signal processing module, that is, there is a gain that affects the amplitude of the output signal of the digital signal processing module in the process from the acquisition position of the first signal to the output end of the digital signal processing module, then the configuration gain is the product of the digital gain and the analog gain. The digital gain can be understood as the gain that affects the amplitude of the output signal of the digital signal processing module in the process from the acquisition position of the first signal to the output end of the digital signal processing module, and the analog gain can be understood as the gain in the analog amplification module that can affect the amplitude of the audio amplification signal.

[0034] In another embodiment, if the first signal acquisition position is close to the output end of the digital signal processing module, that is, there is no gain that affects the amplitude of the output signal of the digital signal processing module in the process from the acquisition position of the first signal to the output end of the digital signal processing module, then the configuration gain includes an analog gain, which can be understood as a gain in the analog amplification module that can affect the amplitude of the audio amplification signal.

[0035] Among them, the amplitude F2 of each second signal is the same as the amplitude of the corresponding audio amplified signal, and the amplitude of the corresponding audio amplified signal can be understood as the amplitude of the corresponding first signal passing through the subsequent digital signal processing module part, digital-to-analog conversion unit and analog amplification module of the acquisition position until the amplitude of the corresponding audio amplified signal is output.

[0036] It should be noted that, since the size of the configured gain is not exactly the same as the gain received by the signal in the process from the first signal to the audio amplified signal in the actual circuit, there will be a deviation between the amplitude F2 of the audio amplified signal and the second signal, but this deviation is acceptable to the present technical solution and will not affect the beneficial effects of the present technical solution. Therefore, to a certain extent, it can be considered that the amplitude F2 of the audio amplified signal is the same as that of the second signal.

[0037] In one embodiment, after generating the current second signal based on the current first signal, the dynamic modulation method of the Class D amplifier also includes smoothing the N second signals within the first time and outputting a second smoothed signal, wherein the amplitude of the second smoothed signal Avg = (T1 + T2 + ... + TN) / N, wherein N is a positive integer, and TN is used to characterize the amplitude of the Nth second signal within the first time.

[0038] In another embodiment, after generating the current second signal according to the current first signal, the dynamic modulation method of the class D amplifier further includes smoothing the current second signal, outputting the second smoothed signal, and the amplitude of the output Nth second smoothed signal Avg2 = Avg1× alpha+ TN×(1-alpha), wherein N is a positive integer, TN is used to characterize the amplitude of the Nth second signal, Avg1 is used to characterize the amplitude of the (N-1)th second smoothed signal, alpha is used to characterize the smoothing weight of the smoothing process, and 0<alpha<1. Among them, those skilled in the art can set different values ​​of alpha according to actual needs, for example, it can be 0.9.

[0039] The smoothing process on the current second signal can prevent a sudden change in the average duty cycle of the subsequent audio amplified signal caused by a sudden change in the second signal in a short period of time.

[0040] A current control signal C{...} is generated according to the current second signal to control an average duty cycle of the audio amplification signal.

[0041] In this embodiment, the control signal C{...} controls the average duty cycle of the audio amplified signal by controlling the common mode level of the analog amplification module. Of course, those skilled in the art will appreciate that there are many other ways to change the average duty cycle of the audio amplified signal, all of which are within the scope of protection of the present invention.

[0042] In one embodiment, please refer to Figure 3 , generating a current control signal C{...} according to the current second signal to control the average duty cycle of the audio amplified signal may include: A plurality of determination thresholds D{...} are provided, and the plurality of determination thresholds D{...} correspond one-to-one to a plurality of duty cycles.

[0043] In this embodiment, the plurality of judgment thresholds D{...} include N judgment thresholds D{...} set in ascending order, the N judgment thresholds D{...} set in ascending order correspond to N duty cycles set in ascending order, and in any two adjacent judgment thresholds D{...}, the latter judgment threshold D{...} is greater than the former judgment threshold D{...}, and N is a positive integer. The difference between the duty cycles corresponding to any two adjacent judgment thresholds D{...} may be the same or different, and the maximum duty cycle is less than or equal to 50%.

[0044] Obtain a first judgment threshold M1: if the current second signal is an initial second signal, use one of the several judgment thresholds D{...} as the first judgment threshold M1; if the current second signal is a changed second signal, use the second judgment threshold M2 formed under the previous second signal as the first judgment threshold M1.

[0045] The amplitude F2 of the current second signal is compared with the first judgment threshold M1 to adjust or maintain the first judgment threshold M1 to form a second judgment threshold M2 under the current second signal, and a current control signal C{...} is generated to control the average duty cycle of the audio amplified signal.

[0046] Among them, please refer to Figure 4 , comparing the amplitude F2 of the current second signal with the first judgment threshold M1 to adjust or maintain the first judgment threshold M1 to form a second judgment threshold M2 under the current second signal, and generating a current control signal C{...} to control the average duty cycle of the audio amplified signal, may include: Set the first value V1 to 0 and the second value V2 to 0. The first value V1 is used to represent the number of consecutive times that the amplitude F2 of the second signal is greater than the first judgment threshold M1, and the second value V2 is used to represent the number of consecutive times that the amplitude F2 of the second signal is less than the first judgment threshold M1.

[0047] The amplitude F2 of the current second signal is compared with the first judgment threshold M1 to update the first value V1 and the second value V2: if the amplitude F2 of the current second signal is greater than the first judgment threshold M1, the first value V1 is increased by 1, and the second value V2 is cleared; if the amplitude F2 of the current second signal is less than the first judgment threshold M1, the second value V2 is increased by 1, and the first value V1 is cleared; if the amplitude F2 of the current second signal is equal to the first judgment threshold M1, both the first value V1 and the second value V2 are cleared.

[0048] According to the first value V1 and the second value V2, the second judgment threshold M2 is formed, and a current control signal C{...} is generated: if the first value V1 is m, the first value V1 is cleared, the judgment threshold after the current first judgment threshold M1 is used as the second judgment threshold M2, and the current control signal C{...} is generated to increase the average duty cycle of the audio amplified signal to the duty cycle corresponding to the second judgment threshold M2; if the second value V2 is n, the second value V2 is cleared, the judgment threshold before the current first judgment threshold M1 is used as the second judgment threshold M2, and the current control signal C{...} is generated to reduce the average duty cycle of the audio amplified signal to the duty cycle corresponding to the second judgment threshold M2; if the first value V1 is less than m and the second value V2 is less than n, the current first judgment threshold M1 is used as the second judgment threshold M2, and the current control signal C{...} is generated to keep the average duty cycle of the audio amplified signal the same as the duty cycle corresponding to the second judgment threshold M2, and m and n are both positive integers. Among them, m and n can be the same or different, and m and n can be set according to actual conditions.

[0049] For details, please refer to Figure 4, initially, that is, before the first second signal is input, the first value is set to 0, the second value is set to 0, and the first judgment threshold M1 is the x-th judgment threshold D{x}, that is, M1=D{x}. If the amplitude F2 of the current second signal is greater than the first judgment threshold M1, the first value V1 is increased by 1, and the second value V2 is cleared; if the amplitude F2 of the current second signal is less than the first judgment threshold M1, the second value V2 is increased by 1, and the first value V1 is cleared; if the amplitude F2 of the current second signal is equal to the first judgment threshold M1, both the first value V1 and the second value V2 are cleared. Therefore, when the amplitudes F2 of the m second signals continuously input are all greater than the first judgment threshold D{x}, the first value V1=m, the second value V2=0, at this time, the second judgment threshold M2 formed is the next judgment threshold of the current first judgment threshold M1=D{x}, that is, M2=D{x+1}, and the corresponding control signal C{x+1} is generated to control the average duty cycle of the audio amplified signal to the duty cycle corresponding to the second judgment threshold M2=D{x+1}; when the amplitudes F2 of the n second signals continuously input are all less than the first judgment threshold D{x}, the second value V2=n, the first value V1=0, at this time, the second judgment threshold formed is the previous judgment threshold of the current first judgment threshold M1=D{x}, that is, M2=D{x-1}, and the corresponding control signal C{x+1} is generated. x-1}, to control the average duty cycle of the audio amplified signal to the duty cycle corresponding to the second judgment threshold M2=D{x-1}; when the first value V1 is less than m and the second value V2 is less than n, the current first judgment threshold M1=D{x} is used as the second judgment threshold M2=D{x}, and the current control signal C{x} is generated to keep the average duty cycle of the audio amplified signal the same as the duty cycle corresponding to the second judgment threshold M2=D{x}. Therefore, the average duty cycle of the audio amplified signal is adjusted progressively in sequence, so that the change of the duty cycle each time can be reduced, thereby reducing the sound quality loss caused by the duty cycle. If m is greater than 1, the average duty cycle of the audio amplified signal will be increased only when the amplitudes F2 of m consecutive second signals are judged to be greater than the first judgment threshold M1. If n is greater than 1, the average duty cycle of the audio amplified signal will be reduced only when the amplitudes F2 of n consecutive second signals are judged to be less than the first judgment threshold M1. This can avoid sudden changes and frequent changes in the average duty cycle of the audio amplified signal caused by sudden changes in the second signal, thereby increasing the stability of the average duty cycle of the audio amplified signal.

[0050] In one embodiment, the control signal C{...} includes M different control signals C{...}, and the M control signals C{...} correspond one-to-one to M different duty cycles, so as to control the average duty cycle of the audio amplified signal to be the corresponding duty cycle.

[0051] In another embodiment, the control signal C{...} includes three control signals to increase, decrease or maintain the average duty cycle of the audio amplified signal. In this case, the analog amplification module further includes a signal parsing unit for converting the received control signal into a control signal corresponding to a specific duty cycle to control the average duty cycle of the audio amplified signal to be the corresponding duty cycle.

[0052] In another embodiment, generating a current control signal C{...} according to the current second signal to control the average duty cycle of the audio amplified signal may include: A plurality of determination thresholds D{...} are provided, and the plurality of determination thresholds D{...} correspond one-to-one to a plurality of duty cycles.

[0053] A plurality of judgment levels corresponding one to one with the plurality of judgment thresholds D{...} are provided.

[0054] Obtain the corresponding first judgment threshold M1 according to the first judgment level: if the current second signal is the initial second signal, take the preset judgment level as the first judgment level, and the judgment threshold D{...} corresponding to the first judgment level as the first judgment threshold M1; if the current second signal is the changed second signal, take the second judgment level formed under the previous second signal as the first judgment level, and the judgment threshold D{...} corresponding to the second judgment level as the first judgment threshold M1.

[0055] In this embodiment, please refer to Figure 5 , Figure 5 It is a flowchart of a method for obtaining a corresponding first judgment threshold according to a first judgment level in a dynamic modulation method of a Class D amplifier provided by another embodiment of the present invention. A step-by-step judgment method is adopted to obtain a corresponding first judgment threshold M1 according to the first judgment level. For example, starting from the Mth judgment level, if the first judgment level is judged to be the Mth level, then the first judgment threshold M1 is equal to the Mth judgment threshold corresponding to the Mth judgment level. If the first judgment level is judged not to be equal to the Mth level, then the first judgment level will continue to be judged whether it is the M-1th judgment level.

[0056] The amplitude F2 of the current second signal is compared with the first judgment threshold M1 to adjust or maintain the first judgment level, form a second judgment level under the current second signal, and generate a current control signal C{...} to control the average duty cycle of the audio amplified signal.

[0057] Among them, comparing the amplitude F2 of the current second signal with the first judgment threshold M1 to adjust or maintain the first judgment level to form a second judgment level under the current second signal, and generating a current control signal C{...} to control the average duty cycle of the audio amplified signal may include: Set the first value V1 to 0 and the second value V2 to 0. The first value V1 is used to represent the number of consecutive times that the amplitude F2 of the second signal is greater than the first judgment threshold M1, and the second value V2 is used to represent the number of consecutive times that the amplitude F2 of the second signal is less than the first judgment threshold M1.

[0058] The amplitude F2 of the current second signal is compared with the first judgment threshold M1 to update the first value V1 and the second value V2: if the amplitude F2 of the current second signal is greater than the first judgment threshold M1, the first value V1 is increased by 1, and the second value V2 is cleared; if the amplitude F2 of the current second signal is less than the first judgment threshold M1, the second value V2 is increased by 1, and the first value V1 is cleared; if the amplitude F2 of the current second signal is equal to the first judgment threshold M1, both the first value V1 and the second value V2 are cleared.

[0059] According to the first value V1 and the second value V2, the second judgment level is formed, and the current control signal C{...} is generated: if the first value V1 is m, the first value V1 is cleared, the judgment level after the current first judgment level is used as the second judgment level, and the current control signal C{...} is generated to increase the average duty cycle of the audio amplified signal to the duty cycle corresponding to the second judgment threshold M2; if the second value V2 is n, the second value V2 is cleared, the judgment level before the current first judgment level is used as the second judgment level, and the current control signal C{...} is generated to reduce the average duty cycle of the audio amplified signal to the duty cycle corresponding to the second judgment threshold M2; if the first value V1 is less than m and the second value V2 is less than n, the current first judgment level is used as the second judgment level, and the current control signal C{...} is generated to keep the average duty cycle of the audio amplified signal the same as the duty cycle corresponding to the second judgment threshold M2, and m and n are both positive integers. Among them, m and n can be the same or different, and m and n can be set according to actual conditions.

[0060] In summary, by dynamically adjusting the average duty cycle of the audio amplified signal, the average duty cycle of the audio amplified signal is made to be a suitable duty cycle to reduce the power consumption of the circuit, that is, the average duty cycle of the audio amplified signal is kept at a low level when there is no audio input, thereby reducing the static power consumption, and at low and medium power, the loss caused by the inductor ripple current is also reduced.

[0061] An embodiment of the present invention further provides an electronic circuit for implementing the dynamic modulation method of the class D amplifier in the above embodiment.

[0062] Among them, since the signal collected from the digital signal processing module is a digital signal, the circuit for implementing the modulation method of the class D amplifier in the above embodiment is a digital circuit, and the structure of the digital circuit is simpler than that of the analog circuit.

[0063] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A dynamic modulation method for a class D amplifier, wherein the class D amplifier comprises a digital signal processing module, and the class D amplifier simulates and amplifies a digital audio signal obtained in the digital signal processing module to output an audio amplified signal, characterized in that: include: Continuously collecting a first signal from the digital signal processing module; generating a current second signal according to the current first signal, wherein the amplitude of the current second signal is the same as the amplitude of the audio amplified signal; Generate a current control signal according to the current second signal to control the average duty cycle of the audio amplified signal, including: providing a plurality of judgment thresholds, wherein the plurality of judgment thresholds correspond to a plurality of duty cycles one by one; obtain a first judgment threshold: if the current second signal is an initial second signal, use one of the plurality of judgment thresholds as the first judgment threshold; if the current second signal is a changed second signal, use the second judgment threshold formed under the previous second signal as the first judgment threshold; compare the amplitude of the current second signal with the first judgment threshold to adjust or maintain the first judgment threshold, form the second judgment threshold under the current second signal, and generate the current control signal to control the average duty cycle of the audio amplified signal.

2. The dynamic modulation method of a class D amplifier according to claim 1, characterized in that: The acquisition position of the first signal is any position in the digital signal processing module.

3. The dynamic modulation method of a class D amplifier according to claim 2, characterized in that: Generating a current second signal according to the current first signal, wherein the amplitude of the current second signal is the same as the amplitude of the audio amplified signal, comprising: Obtaining a configuration gain A, where the configuration gain A is used to characterize the product of various gains that affect the amplitude of the audio amplification signal in the process from the first signal at the corresponding collection position to the output audio amplification signal, and each collection position has a corresponding configuration gain A; A current second signal is generated according to the current first signal and the configured gain A, wherein the amplitude of the current second signal is F2=A×F1, and F1 is used to characterize the amplitude of the current first signal.

4. The dynamic modulation method of a class D amplifier according to claim 1, characterized in that: The Class D amplifier also includes an analog amplification module, an input end of the analog amplification module is coupled to the digital signal processing module through a digital-to-analog conversion unit, an output end of the analog amplification module is used to output an audio amplification signal, and the control signal controls the duty cycle of the audio amplification signal by controlling the common mode level of the analog amplification module.

5. The dynamic modulation method of a class D amplifier according to claim 1, characterized in that: Generating a current control signal according to the current second signal to control the average duty cycle of the audio amplified signal also includes: Providing a number of judgment levels corresponding to a number of judgment thresholds; Obtain the corresponding first judgment threshold according to the first judgment level: if the current second signal is the initial second signal, use the preset judgment level as the first judgment level, and the judgment threshold corresponding to the first judgment level as the first judgment threshold; if the current second signal is the changed second signal, use the second judgment level formed under the previous second signal as the first judgment level, and the judgment threshold corresponding to the second judgment level as the first judgment threshold.

6. The dynamic modulation method of a class D amplifier according to claim 1, characterized in that: The plurality of judgment thresholds include M judgment thresholds arranged in ascending order, the M judgment thresholds arranged in ascending order correspond to M duty cycles arranged in ascending order, and in any two adjacent judgment thresholds, the latter judgment threshold is greater than the former judgment threshold, M is a positive integer, and the amplitude of the current second signal is compared with the first judgment threshold to adjust or maintain the first judgment threshold to form a second judgment threshold, and a current control signal is generated to control the average duty cycle of the audio amplified signal, including: Set a first value to 0 and a second value to 0, wherein the first value is used to represent the number of consecutive times that the amplitude of the second signal is greater than the first judgment threshold, and the second value is used to represent the number of consecutive times that the amplitude of the second signal is less than the first judgment threshold; Compare the amplitude of the current second signal with the first judgment threshold to update the first value and the second value: if the amplitude of the current second signal is greater than the first judgment threshold, the first value is increased by 1, and the second value is cleared; if the amplitude of the current second signal is less than the first judgment threshold, the second value is increased by 1, and the first value is cleared; if the amplitude of the current second signal is equal to the first judgment threshold, the first value and the second value are both cleared; According to the first value and the second value, the second judgment threshold is formed, and a current control signal is generated: if the first value is m, the first value is cleared, a judgment threshold after the current first judgment threshold is used as the second judgment threshold, and a current control signal is generated to increase the average duty cycle of the audio amplified signal to the duty cycle corresponding to the second judgment threshold; if the second value is n, the second value is cleared, a judgment threshold before the current first judgment threshold is used as the second judgment threshold, and a current control signal is generated to reduce the average duty cycle of the audio amplified signal to the duty cycle corresponding to the second judgment threshold; if the first value is less than m and the second value is less than n, the current first judgment threshold is used as the second judgment threshold, and a current control signal is generated to keep the average duty cycle of the audio amplified signal the same as the duty cycle corresponding to the second judgment threshold, and m and n are both positive integers.

7. The dynamic modulation method of a class D amplifier according to claim 1, characterized in that: Before comparing the amplitude of the current second signal with the first judgment threshold, the method also includes: smoothing the N second signals within the first time, outputting a second smoothed signal, the amplitude of the second smoothed signal Avg = (T1 + T2 + ... + TN) / N, N is a positive integer, and TN is used to characterize the amplitude of the Nth second signal within the first time.

8. The dynamic modulation method of a class D amplifier according to claim 1, characterized in that: Before comparing the amplitude of the current second signal with the first judgment threshold, the method also includes: smoothing the current second signal, outputting a second smoothed signal, and the amplitude of the output Nth second smoothed signal Avg2= Avg1×alpha+ TN×(1-alpha), where N is a positive integer, TN is used to characterize the amplitude of the Nth second signal, Avg1 is used to characterize the amplitude of the (N-1)th second smoothed signal, alpha is used to characterize the smoothing weight of the smoothing process, and 0<alpha<1.

9. An electronic circuit, characterized in that: A dynamic modulation method for implementing a class D amplifier as claimed in any one of claims 1 to 8.

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