阅读说明：本技术 D类功放的上电噪声抑制电路、方法和装置 (D class power amplifier powers on noise suppression circuit, method and apparatus ) 是由 魏建磊 丁庆 于 2019-08-02 设计创作，主要内容包括：本发明涉及一种D类功放的上电噪声抑制电路、方法和装置。数字输入模块,数字输入模块用于接收数字音频信号,并将数字音频信号输入D类功放模块；噪声抑制模块,噪声抑制模块用于检测数字输入模块中的数字音频信号输入,并且在检测到D类功放模块上电时,将D类功放模块中脉宽调制的占空比的初始值设置为预设值,当噪声抑制模块检测到数字输入模块中有数字音频信号输入时,根据数字音频信号的幅值,设置工作值；预设值小于工作值。本发明可以在实现上电噪声抑制的情况下,降低电路成本和电路体积。(Noise suppression circuit, method and apparatus are powered on the present invention relates to a kind of D class power amplifier.Digital input module, digital input module input D class power amplifier module for receiving digital audio and video signals, and by digital audio and video signals；Noise suppression module, noise suppression module is used to detect the digital audio and video signals input in digital input module, and when detecting that D class power amplifier module powers on, preset value is set by the initial value of the duty ratio of pulsewidth modulation in D class power amplifier module, when noise suppression module, which detects in digital input module, digital audio and video signals input, according to the amplitude of digital audio and video signals, working value is set；Preset value is less than working value.The present invention can reduce circuit cost and circuit volume in realization in the case where electronic Noise Suppression.)

1. a kind of D class power amplifier powers on noise suppression circuit characterized by comprising

Digital input module, the digital input module are used to receive digital audio and video signals, and the digital audio and video signals are defeated Enter D class power amplifier module；

Noise suppression module, the digital audio and video signals that the noise suppression module is used to detect in the digital input module are defeated Enter, and when detecting that D class power amplifier module powers on, the initial value of the duty ratio of pulsewidth modulation in D class power amplifier module is arranged For preset value；

When the noise suppression module, which detects, has digital audio and video signals input in the digital input module, according to the number The working value is arranged in the amplitude of word audio signal；The preset value is less than working value.

2. circuit according to claim 1, which is characterized in that it is defeated that the digital input module is also used to detect the number Enter the volume amplitude of module；

The noise suppression module receives the volume amplitude.

3. circuit according to claim 2, which is characterized in that the noise suppression module is also used to the volume amplitude It is compared with pre-set threshold value, according to comparison result, generates pulse-width control signal, the pulse-width control signal is for controlling The working value of pulsewidth modulation in D class power amplifier module processed.

4. circuit according to claim 1, which is characterized in that the D class power amplifier module includes pulse width modulator and power Driving stage；

The analog audio signal output of two half-bridge switch of the power drive grade is fed back to corresponding by negative-feedback unit Two inputs of the pulse width modulator.

5. circuit according to claim 4, which is characterized in that the noise suppression module connects the pulse width modulator；

The pulse-width control signal of generation is sent to the pulse width modulator, the pulse width modulator root by the noise suppression module Exporting setting output duty cycle according to the pulse-width control signal is working value.

6. circuit according to any one of claims 1 to 5, which is characterized in that the noise suppression module will be in D class power amplifier The initial value of the duty ratio of pulsewidth modulation is set as 10%；

The working value of the duty ratio of pulsewidth modulation is set as 50% in D class power amplifier.

7. circuit according to any one of claims 1 to 6, which is characterized in that the duty ratio of the pulsewidth modulation is pulsewidth The common mode duty ratio of modulation.

8. a kind of D class power amplifier powers on noise suppressing method characterized by comprising

When D class power amplifier module powers on, the duty ratio that the D class power amplifier module pulsewidth modulation is arranged is preset value；

When detecting in digital input module has digital audio and video signals input, the number of the digital input module output is received The audio amplitude of audio signal；

According to the audio amplitude, pulse-width control signal is generated, and the pulse-width control signal is sent to D class power amplifier module, So that the D class power amplifier module carries out audio output with the duty ratio of working value；The preset value is less than the working value.

9. according to the method described in claim 8, generate pulse-width control signal it is characterized in that, according to the audio amplitude, and The pulse-width control signal is sent to D class power amplifier module, comprising:

The audio amplitude is compared with pre-set threshold value, according to comparison result, generates pulse-width control signal；

The pulse-width control signal is sent to D class power amplifier module.

10. a kind of D class power amplifier powers on Noise Suppression Device characterized by comprising

Detection module is powered on, for the duty of the pulsewidth modulation of the D class power amplifier module to be arranged when D class power amplifier module powers on Than for preset value；

Amplitude detection module, for receiving the number when detecting in digital input module has digital audio and video signals input The audio amplitude of the digital audio and video signals of input module output；

Duty cycle control module, for according to the audio amplitude, generating pulse-width control signal, and by the pulse-width control signal It is sent to D class power amplifier module, so that the D class power amplifier module carries out audio output with the duty ratio of working value；The preset value Less than the working value.

Technical field

The present invention relates to power electronics field, more particularly to a kind of D class power amplifier power on noise suppression circuit and Method.

Background technique

The purposes of audio-frequency amplifier is to reappear input audio signal on sounding output element, provide required for volume and Power level --- guarantee fidelity, high efficiency and the low distortion of reproduction.In face of this task, class-D amplifier performance Various advantages out.In open loop D class power amplifier, power supply noise is almost directly coupled to output loudspeaker, has very little Inhibiting effect.It is because power supply is connected to low pass by a low-down resistance by output stage transistor that this thing happens Filter.Filter inhibits high-frequency noise, but all audio frequencies can all pass through, including audio-frequency noise.

In traditional technology, by the way of analog circuit, an input signal changed over time is generated, to solve D Noise problem of the class method device when powering on.However, circuit realizes complexity in traditional technology, should consider to generate input signal Size, also to consider timing, realize complicated, higher cost so as to cause analog circuit.

Summary of the invention

Based on this, it is necessary to for first there is upper electronic Noise Suppression to realize challenge, provide a kind of powering on for D class power amplifier and make an uproar Sound suppression circuit and method.

A kind of D class power amplifier powers on noise suppression circuit, comprising:

Digital input module, the digital input module believe the digital audio for receiving digital audio and video signals Number input D class power amplifier module；

Noise suppression module, the noise suppression module are used to detect the digital audio and video signals in the digital input module Input, and when detecting that D class power amplifier module powers on, the initial value of the duty ratio of pulsewidth modulation in D class power amplifier module is set It is set to preset value；

When the noise suppression module, which detects, has digital audio and video signals input in the digital input module, according to institute The working value is arranged in the amplitude for stating digital audio and video signals；The preset value is less than working value.

The digital input module is also used to detect the volume width of the digital input module in one of the embodiments, Value；The noise suppression module receives the volume amplitude.

The noise suppression module is also used to the volume amplitude and pre-set threshold in one of the embodiments, Value is compared, and according to comparison result, generates pulse-width control signal, the pulse-width control signal is for controlling D class power amplifier module The common mode operation value of middle pulsewidth modulation.

The D class power amplifier module includes pulse width modulator and power drive grade in one of the embodiments,；The power The analog audio signal of two half-bridge switch of driving stage, which is exported, feeds back to the corresponding pulsewidth modulation by negative-feedback unit Two inputs of device.

The noise suppression module connects the pulse width modulator in one of the embodiments,；The noise suppression module The pulse-width control signal of generation is sent to the pulse width modulator by block, and the pulse width modulator is according to the pulse-width control signal Output setting output duty cycle is working value.

In one of the embodiments, the noise suppression module by D class power amplifier the duty ratio of pulsewidth modulation it is initial Value is set as 10%；The working value of the duty ratio of pulsewidth modulation is set as 50% in D class power amplifier.

The duty ratio of the pulsewidth modulation is the common mode duty ratio of pulsewidth modulation in one of the embodiments,.

A kind of D class power amplifier powers on noise suppressing method, comprising:

When D class power amplifier module powers on, the duty ratio that the D class power amplifier module pulsewidth modulation is arranged is preset value；

When detecting in digital input module has digital audio and video signals input, the digital input module output is received The audio amplitude of digital audio and video signals；

According to the audio amplitude, pulse-width control signal is generated, and the pulse-width control signal is sent to D class power amplifier mould Block, so that the D class power amplifier module carries out audio output with the duty ratio of working value；The preset value is less than the working value.

The audio amplitude is compared with pre-set threshold value in one of the embodiments, is tied according to comparing Fruit generates pulse-width control signal；The pulse-width control signal is sent to D class power amplifier module.

A kind of D class power amplifier powers on Noise Suppression Device, comprising:

Detection module is powered on, for the pulsewidth modulation of the D class power amplifier module to be arranged when D class power amplifier module powers on Duty ratio is preset value；

Amplitude detection module, for when detecting in digital input module has digital audio and video signals input, described in reception The audio amplitude of the digital audio and video signals of digital input module output；

Duty cycle control module, for according to the audio amplitude, generating pulse-width control signal, and by the pulse-width controlled Signal is sent to D class power amplifier module, so that the D class power amplifier module carries out audio output with the duty ratio of working value；It is described pre- If value is less than the working value.

Above-mentioned D class power amplifier powers on noise suppression circuit, method and apparatus, using digital input module, receives digital sound Pulsewidth modulation in D class power amplifier module is arranged when detecting that D class power amplifier module powers in the input of frequency signal, noise suppression module The initial value of duty ratio is preset value, when having digital audio and video signals input in detecting digital input module, passes through audio width Value detection, the working value of corresponding output pulse width modulation.It is exported when due to powering on the duty ratio of preset value, so as to significantly The upper electric noise that the mismatch of LC filter introduces is reduced, and the embodiment of the present invention is realized by the way of digital circuit, can be with By all circuit packages in a chip, to considerably reduce circuit volume and cost.

Detailed description of the invention

Fig. 1 is the structural schematic diagram for powering on noise suppression circuit of D class power amplifier in one embodiment；

Fig. 2 is the structural schematic diagram for powering on noise suppression circuit of D class power amplifier in another embodiment；

Fig. 3 is the schematic flow chart for powering on noise suppressing method of D class power amplifier in one embodiment；

Fig. 4 is the schematic flow chart for powering on Noise Suppression Device of D class power amplifier in one embodiment.

Specific embodiment

Purpose, technical solution and technical effect for a better understanding of the present invention, below in conjunction with drawings and examples Further explaining illustration is carried out to the present invention.State simultaneously, embodiments described below for explaining only the invention, not For limiting the present invention

In one embodiment, as shown in Figure 1, proposing a kind of structural representation for powering on noise suppression circuit of D class power amplifier Figure, the noise suppression circuit that powers on of D class power amplifier specifically include that digital input module 102 and noise suppression module 104, D class power amplifier Module 106 can be common D-type power amplifier.

Directly it is connected with D class power amplifier module 106 to can be seen that digital input module 102 in Fig. 1, numeral input mould Block can receive digital audio and video signals input, so that received digital audio and video signals, which are sent to D class power amplifier module 106, carries out function Rate is amplified with audio output.

D class power amplifier module 106 carries out signal output when carrying out power amplification, with the duty ratio of certain pulsewidth modulation, Due to the audio signal and phonation unit almost direct-coupling of output, most of noise can be exported with audio form.

Noise suppression module 104 is directly connected with digital input module 102 and D class power amplifier module 106, i.e., from numeral input Module 102 acquires the audio amplitude of digital audio and video signals, and D class power amplifier module is fed back in the form of pulse-width control signal 106, to realize the pulse-width controlled of D class power amplifier module.When realizing noise suppression module, the shape of digital circuit can be used Formula, such as the logical code for carrying out specified function to digit chip are write, so that chip be written, realize noise suppression module.Cause This, the noise suppression circuit that powers on of D class power amplifier can be integrated on a single die, to reduce the volume of circuit.

Above-mentioned D class power amplifier powers on noise suppression circuit in specific implementation, specific as follows: on D class power amplifier module 106 Electricity is equivalent to the power-on operation of D class power amplifier module, and the duty ratio that D class power amplifier module 106 is arranged in noise suppression module 104 is pre- If value, and continue to detect in digital input module 102 whether have audio signal input, digital input module 102 waits number Audio signal input, when noise suppression module 104, which detects, has digital audio and video signals input in digital input module 102, root According to the amplitude of audio signal, pulse-width control signal is generated, and pulse-width control signal is sent to D class power amplifier module 106, so that D class power amplifier module 106 sets working value for output duty cycle according to pulse-width control signal, and working value is greater than preset value.

It is worth noting that noise suppression module 104 detects digital audio and video signals input, the side of active detecting can be used Formula, can also be by the way of passive detection, and active detecting refers to digital audio and video signals in monitoring digital input module 102 Situation is transmitted, passive detection refers to that digital input module 102 is waited to send digital audio and video signals to noise suppression module 104 Information.In addition, can choose a ginseng during gradually setting working value by preset value for the duty ratio of pulsewidth modulation According to, for example, select audio frequency for referring to, audio amplitude be referring to etc..Furthermore preset value is the root when designing digital circuit According to the numerical value that demand is arranged, such as: 5%, 10% etc..Working value refers to that the output of D class power amplifier module in normal work accounts for Empty ratio, it is however generally that output duty cycle 50%, in addition, the output duty cycle of the D class power amplifier module of concrete model may be different, Working value is arranged according to actual output duty cycle in the present embodiment.

In the present embodiment, using digital input module, digital audio and video signals input is received, noise suppression module is detecting When D class power amplifier module powers on, the initial value that the duty ratio of pulsewidth modulation in D class power amplifier module is arranged is preset value, is being detected It when having digital audio and video signals input in digital input module, is detected by audio amplitude, the working value of corresponding output pulse width modulation. It is exported when due to powering on the duty ratio of preset value, is made an uproar so as to which the powering on for mismatch introducing of LC filter is greatly lowered Sound, and the embodiment of the present invention is realized by the way of digital circuit, can by all circuit packages in a chip, thus Considerably reduce circuit volume and cost.

In one embodiment, the working principle of noise suppression module is as follows: when D class power amplifier module, noise suppression module BOB(beginning of block) work, noise suppression module whether to have audio input in the clock cycle cycle detection digital input module that is arranged, If running without audio input with power up mode, pulsewidth is set as preset value, and pulsewidth is the duty ratio exported, is then controlled Signal coding processed, generates the pulse-width control signal corresponding to preset value, and D class power amplifier module can be with according to pulse-width control signal Preset value carries out duty ratio output.It when detecting audio input, is run with operating mode, detects the audio of digital audio and video signals The working value of pulsewidth is arranged according to audio amplitude for amplitude, then carries out control Signal coding, generates and corresponds to the arteries and veins that the work refers to Width control signal, D class power amplifier module can carry out duty ratio output according to pulse-width control signal with working value.

In another embodiment, audio amplitude detection is carried out for noise suppression module, it can be in noise suppression module Inside executes, and specifically gets digital audio and video signals, then carries out channel separation, smothing filtering and audio amplitude inspection respectively It surveys, to obtain the corresponding audio amplitude of digital audio and video signals.

Digital input module is made of input logic unit in one of the embodiments, and logic input unit can be examined The audio amplitude of input digital audio signal is surveyed, audio amplitude is sent to noise suppression module by logic input unit.This implementation Example provides the case where a kind of detection of audio amplitude carries out not in noise suppression module, and audio amplitude detection equally may be implemented.

Specifically, whether noise suppression module can send audio amplitude by logic input unit, so that it is determined that digital There is digital audio and video signals input in input module.

Noise suppression module receives audio amplitude in one of the embodiments, by volume amplitude with it is pre-set Threshold value is compared, and according to comparison result, generates pulse-width control signal, pulse-width control signal is for controlling in D class power amplifier module The working value of pulsewidth modulation.

Specifically, multiple threshold ranges are pre-set in noise suppression module, then by audio amplitude and various countries' threshold value It is compared, so that it is determined that in the threshold range that audio amplitude is fallen in, and then determine corresponding pulsewidth.

Specifically, providing a kind of threshold value setting example, the comparison rules of audio amplitude and threshold value are as shown in table 1:

1 threshold range of table and the duty ratio table of comparisons

Threshold range/dB	Duty ratio
		0-10	20%
10-20	30%
		20-30	40%
30-40	50%

For example, current audio amplitude is 25dB, then can determine that corresponding duty ratio is 40%, then noise suppressed Pulsewidth modulation is exported in module control D class power amplifier module with 40% duty ratio.

In the present embodiment, since the initial duty cycle of pulsewidth modulation in D class power amplifier module is smaller, initial duty cycle is small to just Common-mode voltage it is few, on LC filter caused by upper electric noise with regard to small.If there is the biggish signal input of audio amplitude at this time, It would be possible that since low duty ratio exports, the saturation for causing pulse width to modulate further results in audio distortion.According to input number The audio amplitude of word audio signal is come the problem of switching output duty cycle, can solve saturation.

In another embodiment, since noise is to export to account in generation, especially power up in duty ratio switching From scratch, the noise of generation is easiest to be audible empty ratio, so small initial duty cycle can inhibit upper electric noise.And audio width Because having there is audio signal output when being worth the switching of increased duty ratio, common mode switching bring noise can be submerged in audio not It can be heard, in order to prevent audio distortion, need to quickly increase common mode duty ratio according to audio amplitude, therefore, exported When the selection of duty ratio, threshold value comparison is only carried out when audio amplitude increases, to keep the output duty cycle of D class power amplifier module most Reach working value fastly.

In the present embodiment, since the initial duty cycle of D class power amplifier module is smaller, electric noise greatly reduces, When carrying out duty ratio switching, due to audio signal existing in channel, noise exports simultaneously with audio signal, noise It much smaller than audio signal, therefore can not be perceived, to realize noise suppressed.The present embodiment is cut by hierarchical duty ratio It changes, also centainly reduces noise.

In one of the embodiments, as shown in Fig. 2, D class power amplifier module includes pulse width modulator 202 and power drive grade 204, the analog audio signal of two half-bridge switch of power drive grade 204, which is exported, feeds back to corresponding arteries and veins by negative-feedback unit Two inputs of wide modulator 202.

Specifically, noise suppression module connects pulse width modulator, noise suppression module is for controlling the defeated of pulse width modulator Duty ratio out.

Noise suppression module sets the initial value of the duty ratio of pulsewidth modulation in D class power amplifier in one of the embodiments, The working value for being set to the duty ratio of pulsewidth modulation in 10%, D class power amplifier is set as 50%.When being powered on so as to realize noise compared with It is small.

The duty ratio of pulsewidth modulation is the common mode duty ratio of pulsewidth modulation in one of the embodiments,.Since differential mode is believed Number output when, noise can cancel out each other, thus only needing to common mode export duty ratio be adjusted.

In one embodiment, as shown in figure 3, provide a kind of D class power amplifier powers on the schematic of noise suppressing method Flow chart, comprising the following steps:

Step 302, when D class power amplifier module powers on, it is default that the duty ratio of the pulsewidth modulation of D class power amplifier module, which is arranged, Value.

It powers on and refers to being powered with the operating voltage of D class power amplifier module, so that D class power amplifier module be made to work normally.

Step 304, when detecting in digital input module has digital audio and video signals input, it is defeated to receive digital input module The audio amplitude of digital audio and video signals out.

Step 306, according to audio amplitude, pulse-width control signal is generated, and pulse-width control signal is sent to D class power amplifier mould Block, so that D class power amplifier module carries out audio output with the duty ratio of working value.

Preset value is less than working value.

In the present embodiment, by setting preset value for the output duty cycle of D class power amplifier module when powering on, due to default Value is less than working value, therefore can reduce electrical noise.It is true using detection audio amplitude for the noise for inhibiting duty ratio to switch Surely the current duty cycle switched, to realize the noise suppressed of whole process.

Audio amplitude is compared with pre-set threshold value in one of the embodiments, it is raw according to comparison result At pulse-width control signal, pulse-width control signal is sent to D class power amplifier module.

The specific implementation for powering on noise suppressing method about D class power amplifier may refer to above for the upper of D class power amplifier The restriction of electronic Noise Suppression circuit, details are not described herein.

In one of the embodiments, as shown in figure 4, providing a kind of knot for powering on Noise Suppression Device of D class power amplifier Structure schematic diagram, comprising: power on detection module 402, amplitude detection module 404 and duty cycle control module 406.

Detection module 402 is powered on, for the pulsewidth modulation of the D class power amplifier module to be arranged when D class power amplifier module powers on Duty ratio be preset value；

Amplitude detection module 404, for receiving institute when detecting in digital input module has digital audio and video signals input State the audio amplitude of the digital audio and video signals of digital input module output；

Duty cycle control module 406, for according to the audio amplitude, generating pulse-width control signal, and by the pulsewidth Control signal is sent to D class power amplifier module, so that the D class power amplifier module carries out audio output with the duty ratio of working value；Institute Preset value is stated less than the working value.

Amplitude detection module 404 is also used to the audio amplitude and pre-set threshold in one of the embodiments, Value is compared, and according to comparison result, generates pulse-width control signal；The pulse-width control signal is sent to D class power amplifier module.

The specific restriction for powering on Noise Suppression Device about D class power amplifier may refer to above for the upper of D class power amplifier The restriction of electronic Noise Suppression method, details are not described herein.The modules of above-mentioned D class power amplifier powered in Noise Suppression Device can It is realized fully or partially through software, hardware and combinations thereof.Above-mentioned each module can be embedded in the form of hardware or independently of meter It calculates in the processor in machine equipment, can also be stored in a software form in the memory in computer equipment, in order to handle Device, which calls, executes the corresponding operation of the above modules.

Each technical characteristic of embodiment described above can be combined arbitrarily, for simplicity of description, not to above-mentioned reality It applies all possible combination of each technical characteristic in example to be all described, as long as however, the combination of these technical characteristics is not deposited In contradiction, all should be considered as described in this specification.

The embodiments described above only express several embodiments of the present invention, and the description thereof is more specific and detailed, but simultaneously It cannot therefore be construed as limiting the scope of the patent.It should be pointed out that coming for those of ordinary skill in the art It says, without departing from the inventive concept of the premise, various modifications and improvements can be made, these belong to protection of the invention Range.Therefore, the scope of protection of the patent of the invention shall be subject to the appended claims.