CN116614091A - Plosive eliminating circuit of class D audio power amplifier - Google Patents

Plosive eliminating circuit of class D audio power amplifier Download PDF

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Publication number
CN116614091A
CN116614091A CN202310902319.2A CN202310902319A CN116614091A CN 116614091 A CN116614091 A CN 116614091A CN 202310902319 A CN202310902319 A CN 202310902319A CN 116614091 A CN116614091 A CN 116614091A
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driving
counter
stage
class
power amplifier
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CN116614091B (en
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兰金保
宋志勋
陈建威
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Shenzhen Qianhai Shenlei Semiconductor Co ltd
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Shenzhen Qianhai Shenlei Semiconductor Co ltd
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
    • H03F1/26—Modifications of amplifiers to reduce influence of noise generated by amplifying elements
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/181—Low-frequency amplifiers, e.g. audio preamplifiers
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/20—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/68—Combinations of amplifiers, e.g. multi-channel amplifiers for stereophonics
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K7/00—Modulating pulses with a continuously-variable modulating signal
    • H03K7/08—Duration or width modulation ; Duty cycle modulation
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
    • Y02D30/00—Reducing energy consumption in communication networks
    • Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Multimedia (AREA)
  • Amplifiers (AREA)

Abstract

The invention relates to the technical field of integrated circuits and discloses a plosive eliminating circuit of a class D audio power amplifier, which is used for eliminating plosive of the class D audio power amplifier. Comprising the following steps: a loop filter, a PWM generator, an auxiliary driving stage resistor, a power output stage, a feedback resistor and an input resistor; the output end of the loop filter is connected with the input end of the PWM generator, the output end of the PWM generator is respectively connected with the input end of the auxiliary driving stage and the input end of the power output stage, the output end of the auxiliary driving stage is connected with the input end of the auxiliary driving stage resistor, the output end of the auxiliary driving stage resistor is connected with the input end of the loop filter, the output end of the power output stage is respectively connected with the input end of the feedback resistor and the loudspeaker, the output end of the feedback resistor is connected with the input end of the loop filter, the input end of the input resistor is used for receiving input voltage, and the output end of the input resistor is connected with the input end of the loop filter.

Description

Plosive eliminating circuit of class D audio power amplifier
Technical Field
The invention relates to the technical field of integrated circuits, in particular to a plosive eliminating circuit of a class D audio power amplifier.
Background
The ClassD power amplifier has the advantages of high efficiency, small volume and the like, and is widely applied to audio systems such as handheld devices, notebook computers, televisions, vehicle-mounted systems and the like for driving a loudspeaker to sound. These systems generally require higher audio quality, and nonlinear distortion requirements reach below 0.01%, so the current mainstream audio class d power amplifier is still based on the design of pure analog circuits. However, due to systematic or random parameter errors in the IC components used in the analog circuit, mismatch occurs in the pair of components that should be precisely matched, resulting in an offset voltage in the output of the class d power amplifier, i.e., the input is 0 but the output is not 0, and the offset voltage is typically between several mV and 20mV. Although the value is very small, when the Class power amplifier D is started and shut down, the offset voltage is output instantaneously, or the offset voltage jumps to 0 instantaneously, namely, an upward or downward step is formed at the moment, an impact is caused on the loudspeaker, the amplitude of the value is generally more than 2-5 mV, and a human ear can hear the loudspeaker to make a slamming sound.
The conventional solution to the pop-click problem is shown in fig. 1 and 2. class d is generally comprised of a loop filter 101, a pwm generator 102, a correction circuit 103, and a power output 104 stage. Fig. 1 shows a schematic diagram of the correction process. Before the ClassD power amplifier is started, offset is corrected, a feedback resistor Rfb106 is disconnected from the power output stage 104, and simultaneously the Rfb106 is connected to a 0.5-time pvdd voltage buffer 105, and the correction circuit finds an input voltage through a binary algorithm to offset the offset voltage of the ClassD power amplifier, wherein the input voltage 107. Fig. 2 shows a schematic diagram of normal operation of class d, loop filter 201, pwm generator 202, correction circuit 203, power output 204, feedback resistor 205, and input resistor 206. After correction is completed, the ClassD power amplifier is started again, so that output impact of the ClassD power amplifier during starting is reduced. However, this approach is sensitive to changes in pvdd, which is typically connected directly to the battery in a portable device. At the beginning, the battery voltage is higher, and after a period of time, the battery voltage drops, and the correction accuracy is lost. In addition, in high voltage applications, where pvdd is as high as 30V or higher, it is not easy to generate pvdd/2 circuits, and the forced power output stage power driver output high and low can be used to correct once each, and the two correction results are averaged as the correction result, but the circuit complexity is increased. In addition, for the class d power amplifier composed of the high-order loop, this method corrects the offset of the first-stage integrator, and the offset of the subsequent integrator and comparator is not corrected, and although these systems are finally suppressed by the loop, at the moment of starting, these offsets have an immediate effect on the systems, and since the bandwidth of the systems is limited, it takes a while to suppress these offsets slowly, so that at the moment of starting, even if the correction is already done very accurately, a pop sound will still be generated.
Disclosure of Invention
The invention provides a plosive eliminating circuit of a class D audio power amplifier, which is used for eliminating plosive of the class D audio power amplifier.
A first aspect of the present invention provides a plosive cancellation circuit of a class d audio power amplifier, the plosive cancellation circuit of the class d audio power amplifier comprising:
a loop filter, a PWM generator, an auxiliary driving stage resistor, a power output stage, a feedback resistor and an input resistor;
the output end of the loop filter is connected with the input end of the PWM generator, the output end of the PWM generator is respectively connected with the input end of the auxiliary driving stage and the input end of the power output stage, the output end of the auxiliary driving stage is connected with the input end of the auxiliary driving stage resistor, the output end of the auxiliary driving stage resistor is connected with the input end of the loop filter, the output end of the power output stage is respectively connected with the input end of the feedback resistor and the loudspeaker, the output end of the feedback resistor is connected with the input end of the loop filter, the input end of the input resistor is used for receiving input voltage, and the output end of the input resistor is connected with the input end of the loop filter.
With reference to the first aspect, in a first implementation manner of the first aspect of the present invention, the plosive cancellation circuit of the class d audio power amplifier is specifically configured to:
when the class d audio power amplifier is started, the driving capability of the auxiliary driving stage is adjusted to be maximum, and the driving capability of the power output stage is adjusted to be 0.
With reference to the first aspect, in a second implementation manner of the first aspect of the present invention, the plosive cancellation circuit of the class d audio power amplifier is specifically configured to:
when the class d audio power amplifier is turned off, the driving capability of the auxiliary driving stage is adjusted to 0, and the driving capability of the power output stage is adjusted to the maximum.
With reference to the first aspect, in a third implementation manner of the first aspect of the present invention, the auxiliary driving stage includes driving of 128 units of driving strength.
With reference to the first aspect, in a fourth implementation manner of the first aspect of the present invention, the power output stage includes 128 driving intensities of units and 128 driving intensities of 16 times.
With reference to the first aspect, in a fifth implementation manner of the first aspect of the present invention, the plosive cancellation circuit of the class d audio power amplifier further includes: a control module; the control module includes: the first counter, the second counter, the first encoder, the second encoder and the inverter.
With reference to the first aspect, in a sixth implementation manner of the first aspect of the present invention, the control module is specifically configured to:
initializing the first counter to a maximum value and generating a first counter output by the first counter prior to starting the class d audio power amplifier;
the output code of the first counter is output to be all 1 through the first encoder, the driving of all unit driving intensity in the auxiliary driving stage is controlled to be started, and the driving of all 16 times of driving intensity in the power output stage is controlled to be closed;
initializing the second counter to a minimum value and generating a second counter output according to the second counter;
and outputting the output code of the second counter to be all 0 through the second encoder, and turning off all the driving of 16 times of driving intensity in the power output stage.
With reference to the first aspect, in a seventh implementation manner of the first aspect of the present invention, the control module is specifically configured to:
at the starting moment of the classD audio power amplifier, performing transient response on the classD audio power amplifier through the auxiliary driving stage, and starting to perform down-counting through the first counter after the transient response is stable;
when the value of the first counter is reduced by 1, the driving of the unit driving intensity in the auxiliary driving stage is turned off, and meanwhile, the driving of the unit driving intensity in the power output stage is turned on until the value of the first counter is reduced to be 0;
after the first counter is all 0, keeping the first counter to be all 0 and stopping counting, meanwhile, starting to count by adding the second counter, and starting one driving of 16 times of driving strength in the power output stage when the value of the second counter is increased by 1, until the second counter reaches the maximum value and stops counting, and finishing the starting process.
With reference to the first aspect, in an eighth implementation manner of the first aspect of the present invention, the control module is specifically configured to:
when the class D audio power amplifier is shut down, the second counter starts to count down, and the drive of 16 times of drive intensity in the power output stage is gradually shut down;
when all the drives with 16 times of the drive intensity in the power output stage are closed, the first counter starts to count in an addition mode, meanwhile, the drives with unit drive intensity in the power output stage are gradually closed, and the drives with unit drive intensity in the auxiliary drive stage are gradually opened;
when the driving of the unit driving intensity in the power output stage is completely closed, the driving of the unit driving intensity in the auxiliary driving stage is completely opened, the output offset of the class D audio power amplifier is gradually reduced to 0, and the first counter and the second counter return to the initial state and wait for the next starting.
In the technical scheme provided by the invention, a PWM generator, an auxiliary driving stage resistor, a power output stage, a feedback resistor and an input resistor are arranged through a loop filter; the output end of the loop filter is connected with the input end of the PWM generator, the output end of the PWM generator is respectively connected with the input end of the auxiliary driving stage and the input end of the power output stage, the output end of the auxiliary driving stage is connected with the input end of the auxiliary driving stage resistor, the output end of the auxiliary driving stage resistor is connected with the input end of the loop filter, the output end of the power output stage is respectively connected with the input end of the feedback resistor and the loudspeaker, the output end of the feedback resistor is connected with the input end of the loop filter, the input end of the input resistor is used for receiving input voltage, and the output end of the input resistor is connected with the input end of the loop filter.
Drawings
FIG. 1 is a schematic diagram of a conventional correction of misalignment used to reduce pop in an embodiment of the present invention;
FIG. 2 is a schematic diagram of a conventional pop reduction by correcting a misalignment in an embodiment of the present invention;
FIG. 3 is a simulated graph of the response of a human ear to signals of different rates of change in an embodiment of the present invention;
fig. 4 (1) is a schematic diagram of a plosive cancellation circuit of a class d audio power amplifier according to an embodiment of the invention;
FIG. 4 (2) is a graph showing the driving capability variation of the auxiliary driving stage and the power output stage during the start-up and shutdown processes according to the embodiment of the present invention;
FIG. 5 (1) is a schematic diagram of a 1-unit driving strength driving and a 16-unit driving strength driving in an embodiment of the present invention;
FIG. 5 (2) is a schematic circuit diagram of an embodiment of the present invention;
FIG. 5 (3) is a schematic diagram of a control module according to an embodiment of the present invention;
fig. 5 (4) is a control schematic diagram in an embodiment of the present invention.
Detailed Description
The embodiment of the invention provides a plosive eliminating circuit of a class D audio power amplifier, which is used for eliminating plosive of the class D audio power amplifier. The terms "first," "second," "third," "fourth" and the like in the description and in the claims and in the above drawings, if any, are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments described herein may be implemented in other sequences than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed or inherent to such process, method, article, or apparatus.
For ease of understanding, a detailed flow of an embodiment of the present invention is described below with reference to fig. 4 (1), and an embodiment of a plosive cancellation circuit of a class d audio power amplifier of the embodiment of the present invention includes: a loop filter, a PWM generator, an auxiliary driving stage resistor, a power output stage, a feedback resistor and an input resistor;
the output end of the loop filter is connected with the input end of the PWM generator, the output end of the PWM generator is respectively connected with the input end of the auxiliary driving stage and the input end of the power output stage, the output end of the auxiliary driving stage is connected with the input end of the auxiliary driving stage resistor, the output end of the auxiliary driving stage resistor is connected with the input end of the loop filter, the output end of the power output stage is respectively connected with the input end of the feedback resistor and the loudspeaker, the output end of the feedback resistor is connected with the input end of the loop filter, the input end of the input resistor is used for receiving input voltage, and the output end of the input resistor is connected with the input end of the loop filter.
The human ear corresponds to a band-pass filter, is most sensitive to sounds around 1KHz, and gradually decreases in sensitivity to sounds exceeding 1KHz and below 1KHz, and sounds exceeding 20KHz and below 20Hz are generally considered to be inaudible to the human ear. Fig. 3 is a corresponding schematic diagram of a filter 301,302 simulating the human ear for two signals, for a sudden step signal waveform 303 passing through the filter to produce a larger spike waveform 304, the amplitude of which generally exceeds the amplitude of the step, and for a slowly varying signal waveform 305, which passes through the filter to produce a waveform 306 with a very small peak amplitude, the output spike may theoretically be less than 1mV if the rate of change is sufficiently slow, and with little correlation to the amplitude of the change. Therefore, the invention considers that the class D power amplifier gradually outputs the offset when being started, slowly stabilizes the offset to the final offset value, gradually reduces the offset when being shut down, and finally returns to 0.
The plosive eliminating circuit of the class D audio power amplifier is specifically used for:
when the class d audio power amplifier is started, the driving capability of the auxiliary driving stage is adjusted to be maximum, and the driving capability of the power output stage is adjusted to be 0.
The plosive eliminating circuit of the class D audio power amplifier is specifically used for:
when the class d audio power amplifier is turned off, the driving capability of the auxiliary driving stage is adjusted to 0, and the driving capability of the power output stage is adjusted to the maximum.
Specifically, fig. 4 (1) is a schematic diagram of a plosive cancellation circuit of the class d audio power amplifier. There are two driving stages with adjustable driving strength, an auxiliary driving stage aux-driver404 and a power output stage power driver403. The circuit comprises a loop filter401, a PWM generator 402, a feedback resistor Rfb406, an auxiliary driving stage resistor Raux405, an input resistor Rin407 and an input voltage Vin. When the auxiliary driving stage aux-driver404 is started, the driving capability of the power output stage power driver403 is adjusted to be maximum, the stabilizing process and the offset establishing process of the circuit system at the moment of starting are completed through the auxiliary driving stage aux-driver404, and the circuit system cannot be output to the loudspeaker 410. After the system is established, the driving capability of the auxiliary driving stage aux-driver404 is reduced linearly, the driving capability of the power output stage power driver403 starts to increase linearly, and the driving capability increase is equal to the reduction of the auxiliary driving stage aux-driver 404. Thus, the reduced driving capability of the auxiliary driving stage aux-driver404 will be provided by the power output stage power driver403, keeping the overall driving capability of this process unchanged. During this process, the maladjustment of the class d power amplifier gradually increases from 0, and as long as the process is controlled slowly enough, the plosive cannot be heard by the human ear. When the driving of the auxiliary driving stage aux-driver404 falls to 0, the output offset at this time has stabilized to the final value, which is to accelerate the increase rate of the driving capability of the power output stage power driver403, and finally reach the maximum driving capability, so that the music can be played normally. The shutdown process is just the reverse of the startup process, and also no plosive sound is generated. The curve 409 in fig. 4 (2) shows the driving capability variation of the auxiliary driving stage aux-driver404 during the start-up and shutdown processes of the system, and the curve 408 in fig. 4 (2) shows the driving capability variation of the power output stage power driver403 during the start-up and shutdown processes.
The auxiliary drive stage includes a drive of 128 units of drive strength.
The power output stage includes 128 drives of unit drive strength and 128 drives of 16 drive strength.
Specifically, in terms of controlling the auxiliary driving stage aux-driver404 and the power output stage power driver403, the control schematic is 511 and 512 in fig. 5 (4), where the auxiliary driving stage aux-driver404 is implemented as the auxiliary driving stage 504 in fig. 5 (2), and includes the driving 501 with 128 driving intensities, and the driving with 1 driving intensity is shown in fig. 5 (1). The power output stage power driver403 is specifically implemented as the power output stage 505 and the power output stage 506 in fig. 5 (2), where the power output stage 505 includes 128 driving strength drives 501, and the power output stage 506 includes 128 driving strength drives 502 that are 16 times, where the 16 driving strength drives are shown in fig. 5 (1).
The plosive cancellation circuit of the class d audio power amplifier further comprises: a control module; the control module includes: the first counter, the second counter, the first encoder, the second encoder and the inverter.
As shown in fig. 5 (3), fig. 5 (3) is a schematic diagram of a control module, and the control module is composed of a first counter 507, a second counter 509, a first encoder 508, a second encoder 510, and an inverter 503. The control signals of the 1-unit driving strength driving 501 and the 16-unit driving strength driving 502 are en, when en is high level, the driving is turned on, and when en is level, the driving is in a high resistance state. The first encoder 508 encodes aux_counter [6:0] into 128-bit thermometer codes, controls the driving of 128 units of driving intensity in the auxiliary driving stages 504, respectively, and the reverse signal controls the driving of 128 units of driving intensity in the power output stages 505, so that the number of on in the auxiliary driving stages 504 and the number of off in the power output stages 505 are equal, and the sum of the number of on in the auxiliary driving stages 504 and the number of on in the power output stages 505 is always equal to 128, simply, one of the power output stages 505 is turned off when one of the auxiliary driving stages 504 is turned off, and one of the power output stages 505 is turned on when one of the auxiliary driving stages 504 is turned off.
The control module is specifically used for:
initializing the first counter to a maximum value and generating a first counter output by the first counter prior to starting the class d audio power amplifier;
the output code of the first counter is output to be all 1 through the first encoder, the driving of all unit driving intensity in the auxiliary driving stage is controlled to be started, and the driving of all 16 times of driving intensity in the power output stage is controlled to be closed;
initializing the second counter to a minimum value and generating a second counter output according to the second counter;
and outputting the output code of the second counter to be all 0 through the second encoder, and turning off all the driving of 16 times of driving intensity in the power output stage.
Specifically, prior to starting the class d audio power amplifier, the first counter 507 is initialized to a maximum value, which outputs aux_counter [6:0] =7' b111_1111 (corresponding to decimal 127), the first encoder encodes aux_counter [6:0] to output aux_en [127:0] as all "1", driving of all unit driving intensities of the control 540 is turned on, and all of the power output stages 505 are turned off. The second counter 509 is initialized to a minimum value, its output drv_counter [5:0] =6' b00_0000 (corresponding to decimal 0), the second encoder encodes the drv_counter [5:0] output drv_en [63:0] to all "0", turning off all 16 times the driving of the driving intensity in the power output stage 506. The entire class d loop now passes through the auxiliary drive stage aux-driver404, wherein the auxiliary drive stage aux-driver404 is embodied as an auxiliary drive stage 504 and Raux405 forming a closed loop, and the power output stage power driver403 is embodied as a power output stage 505 and a power output stage 506 disconnected from the horn.
The control module is specifically used for:
at the starting moment of the classD audio power amplifier, performing transient response on the classD audio power amplifier through the auxiliary driving stage, and starting to perform down-counting through the first counter after the transient response is stable;
when the value of the first counter is reduced by 1, the driving of the unit driving intensity in the auxiliary driving stage is turned off, and meanwhile, the driving of the unit driving intensity in the power output stage is turned on until the value of the first counter is reduced to be 0;
after the first counter is all 0, keeping the first counter to be all 0 and stopping counting, meanwhile, starting to count by adding the second counter, and starting one driving of 16 times of driving strength in the power output stage when the value of the second counter is increased by 1, until the second counter reaches the maximum value and stops counting, and finishing the starting process.
The starting process is as follows, at the moment of starting, the transient response of the class d will be completed by the auxiliary driving stage aux-driver404, after the transient response is stable, the first counter 507 starts to count down, and each time the value of the transient response is reduced by "1", the unit driving in the auxiliary driving stage 504 is turned off, and at the same time the unit driving in the power output stage 505 is turned on, the process continues until the value of the first counter 507 is reduced to all "0", and during the process, the output offset of the class d gradually increases gradually from 0 to the final value, that is, the slow variation process in 305 is realized. After the first counter 507 is all "0", the first counter 507 is kept all "0" and the counting is stopped. The second counter 509 starts to count up, and starts one driving of 16 times driving capability in the power output stage 506 every time its value is increased by "1", and finally reaches the maximum drv_counter [5:0] =6' b11_1111 and stops counting, all driving is started, and the strongest driving force of the whole power output stage power driver is reached, and the starting process is completed.
The control module is specifically used for:
when the class D audio power amplifier is shut down, the second counter starts to count down, and the drive of 16 times of drive intensity in the power output stage is gradually shut down;
when all the drives with 16 times of the drive intensity in the power output stage are closed, the first counter starts to count in an addition mode, meanwhile, the drives with unit drive intensity in the power output stage are gradually closed, and the drives with unit drive intensity in the auxiliary drive stage are gradually opened;
when the driving of the unit driving intensity in the power output stage is completely closed, the driving of the unit driving intensity in the auxiliary driving stage is completely opened, the output offset of the class D audio power amplifier is gradually reduced to 0, and the first counter and the second counter return to the initial state and wait for the next starting.
The shutdown process is as follows, and is an inverse process of starting up, first the second counter 509 starts to count down, the driving in the power output stage 506 is gradually turned off, after all the driving in the power output stage 506 is turned off, the first counter 507 starts to count up, at this time, the driving in the power output stage 505 is gradually turned off, the driving in the auxiliary driving stage 504 is gradually turned on, finally the power output stage 505 is completely turned off, the auxiliary driving stage 504 is completely turned on, the output offset of class d is gradually reduced to 0, and the curve in 305 is realized. At this time, each counter returns to the initial state again and waits for the next start.
In the embodiment of the invention, a PWM generator, an auxiliary driving stage resistor, a power output stage, a feedback resistor and an input resistor are arranged through a loop filter; the output end of the loop filter is connected with the input end of the PWM generator, the output end of the PWM generator is respectively connected with the input end of the auxiliary driving stage and the input end of the power output stage, the output end of the auxiliary driving stage is connected with the input end of the auxiliary driving stage resistor, the output end of the auxiliary driving stage resistor is connected with the input end of the loop filter, the output end of the power output stage is respectively connected with the input end of the feedback resistor and the loudspeaker, the output end of the feedback resistor is connected with the input end of the loop filter, the input end of the input resistor is used for receiving input voltage, and the output end of the input resistor is connected with the input end of the loop filter.
It will be clear to those skilled in the art that, for convenience and brevity of description, specific working procedures of the above-described systems, apparatuses and units may refer to corresponding procedures in the foregoing method embodiments, which are not repeated herein.
The integrated units, if implemented in the form of software functional units and sold or used as stand-alone products, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied essentially or in part or all of the technical solution or in part in the form of a software product stored in a storage medium, including instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a read-only memory (ROM), a random access memory (random acceS memory, RAM), a magnetic disk, or an optical disk, or other various media capable of storing program codes.
The above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims (9)

1. A plosive cancellation circuit of a class d audio power amplifier, the plosive cancellation circuit of the class d audio power amplifier comprising: a loop filter, a PWM generator, an auxiliary driving stage resistor, a power output stage, a feedback resistor and an input resistor;
the output end of the loop filter is connected with the input end of the PWM generator, the output end of the PWM generator is respectively connected with the input end of the auxiliary driving stage and the input end of the power output stage, the output end of the auxiliary driving stage is connected with the input end of the auxiliary driving stage resistor, the output end of the auxiliary driving stage resistor is connected with the input end of the loop filter, the output end of the power output stage is respectively connected with the input end of the feedback resistor and the loudspeaker, the output end of the feedback resistor is connected with the input end of the loop filter, the input end of the input resistor is used for receiving input voltage, and the output end of the input resistor is connected with the input end of the loop filter.
2. The blasts canceling circuit of a class d audio power amplifier of claim 1 wherein said blasts canceling circuit of a class d audio power amplifier is specifically configured to:
when the class d audio power amplifier is started, the driving capability of the auxiliary driving stage is adjusted to be maximum, and the driving capability of the power output stage is adjusted to be 0.
3. The blasts canceling circuit of a class d audio power amplifier of claim 2 wherein said blasts canceling circuit of a class d audio power amplifier is specifically configured to:
when the class d audio power amplifier is turned off, the driving capability of the auxiliary driving stage is adjusted to 0, and the driving capability of the power output stage is adjusted to the maximum.
4. A plosive e cancellation circuit of a class d audio power amplifier according to claim 3, wherein the auxiliary drive stage comprises a drive of 128 units drive strength.
5. The blaster circuit of a class d audio power amplifier of claim 4, wherein the power output stage comprises 128 drives of unit drive strength and 128 drives of 16 drive strength.
6. The blasts cancellation circuit of a class d audio power amplifier of claim 5, further comprising: a control module; the control module includes: the first counter, the second counter, the first encoder, the second encoder and the inverter.
7. The blasts cancellation circuit of a class d audio power amplifier of claim 6, wherein the control module is specifically configured to:
initializing the first counter to a maximum value and generating a first counter output by the first counter prior to starting the class d audio power amplifier;
the output code of the first counter is output to be all 1 through the first encoder, the driving of all unit driving intensity in the auxiliary driving stage is controlled to be started, and the driving of all 16 times of driving intensity in the power output stage is controlled to be closed;
initializing the second counter to a minimum value and generating a second counter output according to the second counter;
and outputting the output code of the second counter to be all 0 through the second encoder, and turning off all the driving of 16 times of driving intensity in the power output stage.
8. The blasts cancellation circuit of a class d audio power amplifier of claim 7, wherein the control module is specifically configured to:
at the starting moment of the classD audio power amplifier, performing transient response on the classD audio power amplifier through the auxiliary driving stage, and starting to perform down-counting through the first counter after the transient response is stable;
when the value of the first counter is reduced by 1, the driving of the unit driving intensity in the auxiliary driving stage is turned off, and meanwhile, the driving of the unit driving intensity in the power output stage is turned on until the value of the first counter is reduced to be 0;
after the first counter is all 0, keeping the first counter to be all 0 and stopping counting, meanwhile, starting to count by adding the second counter, and starting one driving of 16 times of driving strength in the power output stage when the value of the second counter is increased by 1, until the second counter reaches the maximum value and stops counting, and finishing the starting process.
9. The blasts cancellation circuit of a class d audio power amplifier of claim 8, wherein the control module is specifically configured to:
when the class D audio power amplifier is shut down, the second counter starts to count down, and the drive of 16 times of drive intensity in the power output stage is gradually shut down;
when all the drives with 16 times of the drive intensity in the power output stage are closed, the first counter starts to count in an addition mode, meanwhile, the drives with unit drive intensity in the power output stage are gradually closed, and the drives with unit drive intensity in the auxiliary drive stage are gradually opened;
when the driving of the unit driving intensity in the power output stage is completely closed, the driving of the unit driving intensity in the auxiliary driving stage is completely opened, the output offset of the class D audio power amplifier is gradually reduced to 0, and the first counter and the second counter return to the initial state and wait for the next starting.
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