CN102510274A - PWM frequency control method for class-D power amplifiers and device adopting same - Google Patents

PWM frequency control method for class-D power amplifiers and device adopting same Download PDF

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Publication number
CN102510274A
CN102510274A CN2011103708136A CN201110370813A CN102510274A CN 102510274 A CN102510274 A CN 102510274A CN 2011103708136 A CN2011103708136 A CN 2011103708136A CN 201110370813 A CN201110370813 A CN 201110370813A CN 102510274 A CN102510274 A CN 102510274A
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China
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variable
pwm frequency
signal
pwm
power amplifier
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CN2011103708136A
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李春雨
虞培良
李小建
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ZTE Corp
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ZTE Corp
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Priority to CN2011103708136A priority Critical patent/CN102510274A/en
Priority to PCT/CN2012/071216 priority patent/WO2013075413A1/en
Publication of CN102510274A publication Critical patent/CN102510274A/en
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    • 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
    • H03F3/21—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers with semiconductor devices only
    • H03F3/217—Class D power amplifiers; Switching amplifiers

Abstract

The invention discloses a PWM (Pulse-Width Modulation) frequency control method for class-D power amplifiers and a device adopting the same. The method comprises the following steps: class-D power amplifiers are sequentially endowed with different PWM frequencies; in the different PWM frequencies of the class-D power amplifiers, the signal-to-noise ratio of FM (Frequency Modulation) broadcasting signals received by FM receiving modules are sequentially acquired; the PWM frequency value corresponding to the maximum signal-to-noise is acquired and taken as the optimal PWM frequency; and the optimal PWM frequency is designed to the PWM frequency of the class-D power amplifier. By virtue of the technical scheme of the invention, the electromagnetic interference of the class-D power amplifiers on the FM receiving modules is reduced to the minimum, so that a user can receive clear wireless broadcasting signals.

Description

The PWM control method for frequency and the device of D class power amplifier
Technical field
The present invention relates to field of mobile communication, particularly relate to a kind of PWM control method for frequency and device of D class power amplifier.
Background technology
At present, along with the maturation and the development of mobile communication technology, the function of handheld device (for example: mobile phone, MP3 etc.) is more and more, and these functions have been brought very big convenience to people.At present, many handheld devices all have been equipped with frequency modulation(FM) (Frequency Modulation abbreviates FM as) receiver module, have the function that receives the FM broadcast singal, greatly facilitate the user and listen to the FM program.
The FM receiver module can convert the FM broadcast singal to audio signal, after through audio-frequency power amplifier audio signal being amplified then, sends loud speaker to and plays.
In China, the operating frequency of FM receiver module (claiming frequency again) scope is traditionally arranged to be 87.5MHz～108.0MHz, and step-length is 100KHz (being to differ 100KHz at least between the frequency of each FM broadcast singal).Can find out that the operating frequency of FM broadcasting is limited.The FM receiver module must be equipped with antenna just can receive the FM broadcast singal preferably.Handheld terminal generally adopts lead-in wire in the earphone as the antenna of FM receiver module, but the user must insert earphone when listening to radio broadcasting like this, has brought inconvenience to the user.The handheld terminal that has adopts the antenna of ceramic antenna as the FM receiver module, but the price of ceramic antenna is more expensive, has increased the cost of handheld terminal.
In the prior art, also a kind of technology, the lead-in wire of loud speaker that promptly adopts handheld terminal has advantage easy to use, that cost is low as the antenna of FM receiver module.Fig. 1 be the lead-in wire of loud speaker of available technology adopting handheld terminal as the sketch map of the antenna of FM receiver module, as shown in Figure 1, microcontroller connects D power-like amplifier and FM receiver module, the FM receiver module is connected in the D power-like amplifier.
Subjective, the sound that the user broadcasts from loud speaker is usually assessed the reception of FM receiver module, and sound is clear more, noise is more little, explains that the result of broadcast of FM receiver module is good more.Objectively, use this parameter of signal to noise ratio (signal noise ratio) usually, assess the reception of FM receiver module.Signal to noise ratio is big more, explains that signal quality is good more, electronic noise is more little, thereby the sound that loud speaker is broadcasted is clear more, noise is more little.
In the prior art, the FM receiver module just utilizes the signal to noise ratio parameter to realize the function of automatic channel search.Be that the FM receiver module begins from a certain operating frequency, each operating frequency increases a step-length (100KHz), receives the FM broadcast singal.If under a certain operating frequency, the signal to noise ratio of the FM broadcast singal that receives surpasses predetermined threshold, and for example 50dB then is regarded as an effective radio station, and handheld terminal then can be provided with the FM receiver module and be operated in this operating frequency and get off to receive the FM broadcast singal.
At present, handheld terminal is used to drive the audio frequency amplifier of loud speaker, has generally adopted D class power amplifier.So-called D class power amplifier is meant D genus audio power amplifier (being also referred to as digital power amplifier sometimes); It can be transformed into pulse width modulation (Pulse Width Modulation with the simulated audio signal of input; Abbreviate PWM as) pulse signal; The pulse signal of PWM goes to control the conducting or the disconnection of high-power switch device then, thereby drives loud speaker.Generally speaking, the PWM frequency values of D class power amplifier is at 300KHz～1200KHz.The frequency values of the PWM of D class power amplifier, microcontroller can be provided with through communication interface.
Compare characteristics such as the efficient height of D class power amplifier, volume are little with general linear AB class power amplifier.Yet; D class power amplifier also has shortcoming, because the output signal of D class power amplifier is big electric current and is high-speed pwm switch signal, so can produce electromagnetic interference; This interference contains broad frequency spectrum; Can directly have influence on the receptivity of the FM receiver module that is connected with it, cause the quality of reception to descend, thereby the sound that loud speaker is broadcasted contain more noise.
Therefore, need a kind of method of controlling D class power amplifier PWM frequency, D class power amplifier is reduced to the electromagnetic interference of FM receiver module minimum, thereby make the user receive radio broadcasting signal clearly.
Summary of the invention
The present invention provides a kind of PWM control method for frequency and device of D class power amplifier, and D class power amplifier produces electromagnetic interference to the FM receiver module in the prior art to solve, thereby makes the user can't receive the problem of radio broadcasting signal clearly.
The present invention provides a kind of PWM control method for frequency of D class power amplifier, comprising:
D class power amplifier is set gradually different PWM frequencies;
Under the different PWM frequency of D class power amplifier, obtain the signal to noise ratio of the FM broadcast singal that frequency modulation(FM) FM receiver module receives successively;
Obtaining the pairing PWM frequency values of signal to noise ratio maximum in the signal to noise ratio, as best PWM frequency, and is the PWM frequency of D class power amplifier with best PWM frequency configuration with the PWM frequency values.
The present invention also provides a kind of PWM frequency control apparatus of D class power amplifier, comprising:
The signal to noise ratio acquisition module is used for D class power amplifier is set gradually different PWM frequencies, under the different PWM frequency of D class power amplifier, obtains the signal to noise ratio of the FM broadcast singal that frequency modulation(FM) FM receiver module receives successively;
Best PWM frequency acquisition module is used for obtaining the pairing PWM frequency values of signal to noise ratio maximum of signal to noise ratio, with the PWM frequency values as best PWM frequency;
The PWM frequency setting module, being used for best PWM frequency configuration is the PWM frequency of D class power amplifier.
Beneficial effect of the present invention is following:
Through setting gradually the PWM frequency of D class power amplifier; Under the different PWM frequency of D class power amplifier; Obtain the signal to noise ratio of the FM broadcast singal that receives of FM receiver module, and select the PWM frequency values of the pairing D class of signal to noise ratio maximum power amplifier, as the PWM frequency values of best D class power amplifier.Solved in the prior art D class power amplifier FM receiver module has been produced electromagnetic interference; Thereby make the user can't receive the problem of radio broadcasting signal clearly; When the FM receiver module converted the FM broadcast singal into voice signal, the operating frequency that microcontroller is current according to the FM receiver module found the PWM frequency values of best D class power amplifier to carry out sound playing; Thereby D class power amplifier is reduced to minimum to the electromagnetic interference of FM receiver module, make the user can receive radio broadcasting signal clearly.
Description of drawings
Fig. 1 is that the lead-in wire of loud speaker of available technology adopting handheld terminal is as the sketch map of the antenna of FM receiver module;
Fig. 2 is the flow chart of PWM control method for frequency of the D class power amplifier of the embodiment of the invention;
Fig. 3 is the flow chart of detailed process of PWM control method for frequency of the D class power amplifier of the embodiment of the invention;
Fig. 4 is the structural representation of PWM frequency control apparatus of the D class power amplifier of the embodiment of the invention.
Embodiment
D class power amplifier produces electromagnetic interference to the FM receiver module in the prior art in order to solve; Thereby make the user can't receive the problem of radio broadcasting signal clearly; The invention provides a kind of PWM control method for frequency and device of D class power amplifier, reduce to minimum to the electromagnetic interference of FM receiver module D class power amplifier.Below in conjunction with accompanying drawing and embodiment, the present invention is further elaborated.Should be appreciated that specific embodiment described herein only in order to explain the present invention, does not limit the present invention.
Method embodiment
According to embodiments of the invention; A kind of PWM control method for frequency of D class power amplifier is provided; Fig. 2 is the flow chart of PWM control method for frequency of the D class power amplifier of the embodiment of the invention, and is as shown in Figure 2, comprises following processing according to the PWM control method for frequency of the D class power amplifier of the embodiment of the invention:
Step 201 sets gradually different PWM frequencies to D class power amplifier;
Preferably; Before execution in step 201; Can variable be set in advance and with initialization of variable; Wherein, the variable of setting comprises four, is respectively: first variable, peaked second variable of storage signal to noise ratio, the ternary of the current signal to noise ratio of storage and the 4th variable of storing current PWM frequency of storing best PWM frequency.
Step 202 under the different PWM frequency of D class power amplifier, is obtained the signal to noise ratio of the FM broadcast singal that frequency modulation(FM) FM receiver module receives successively;
Preferably, in practical application, step 201 and step 202 are specifically handled as follows:
Step 1, the 4th variable are set to current PWM frequency values;
Step 2, control FM receiver module receives the FM signal broadcasting;
Step 3 is obtained the snr value under the current PWM frequency from the FM receiver module;
Step 4 stores snr value in the ternary into.
Step 203 is obtained the pairing PWM frequency values of signal to noise ratio maximum in the signal to noise ratio, as best PWM frequency, and is the PWM frequency of D class power amplifier with best PWM frequency configuration with the PWM frequency values.
Preferably, in practical application, step 203 specifically comprises following processing:
Step 5, the size of the ternary and second variable relatively, if the value of ternary greater than second variable, then the value with ternary stores second variable into, stores the value of the 4th variable into first variable; If the value of ternary less than second variable, then keeps the value of value and second variable of first variable constant;
Step 6; Make the 4th variable=current PWM frequency values+predetermined steps long value, and judge that the 4th variable whether greater than the power maximum that is provided with in advance, if be judged as is; Then obtain the PWM frequency values in first variable; With the PWM frequency configuration of D class power amplifier is the value in first variable, if be judged as not, then execution in step 1.
Below in conjunction with accompanying drawing, the technique scheme of the embodiment of the invention is elaborated.
In this example, suppose that the PWM frequency values scope of the D class power amplifier that this handheld terminal adopts is 500KHz～600KHz, step-length 10KHz.
Fig. 3 is the flow chart of detailed process of PWM control method for frequency of the D class power amplifier of the embodiment of the invention, and is as shown in Figure 3, comprises following processing:
Step 1 is provided with 4 variablees, and carries out initialization: wherein, 4 variablees are specially:
D_PWM_Best=500KHz, this variable are used to store the PWM frequency values of best D class power amplifier;
FM_SN_Best=0dB, this variable are used to store the maximum of the signal to noise ratio of the FM broadcast singal that receives;
D_PWM=500KHz, this variable are used to store the PWM frequency values of current D class power amplifier;
FM_SN=0dB, this variable are used to store the signal to noise ratio of current FM broadcast singal.
It is D PWM that step 2, microcontroller are provided with D class power amplifier PWM frequency values, and sends to receive to instruct and receive the FM broadcast singal for the FM receiver module, and the signal to noise ratio of redispatching query statement is given the FM receiver module.After microcontroller is received the signal to noise ratio numerical value that the FM receiver module returns, with the signal to noise ratio value storage to the FM_SN variable;
Step 3, the size of comparison FM_SN and FM_SN_Best is if FM_SN more than or equal to FM_SN_Best, then makes D_PWM_Best=D_PWM, FM_SN_Best=FM_SN;
Step 4, D_PWM=D_PWM+10K, if D_PWM smaller or equal to 600KHz, then repeating step 2, step 3 and step 4;
The PWM frequency values that step 5, microcontroller are provided with D class power amplifier is D_PWM_Best, finishes.
According to above-mentioned steps, can obtain data as shown in table 1:
Table 1
D class power amplifier PWM frequency values The signal to noise ratio of FM broadcast singal
500KHz 60dB
510KHz 58dB
520KHz 58dB
530KHz 59dB
540KHz 59dB
550KHz 60dB
560KHz 61dB
570KHz 60dB
580KHz 59dB
590KHz 58dB
600KHz 58dB
PWM frequency values scope at D class power amplifier is 500KHz～600KHz; Under the situation of step-length 10KHz; Can find out that from last table microcontroller sets gradually D class power amplifier PWM frequency values and is: 500KHz, 510KHz, 520KHz, 530KHz, 540KHz, 550KHz, 560KHz, 570KHz, 580KHz, 590KHz, 600KHz.
The FM receiver module is under the situation of the different PWM frequency values of D class power amplifier, and the signal to noise ratio of the FM broadcast singal that receives is followed successively by: 60dB, 58dB, 58dB, 59dB, 59dB, 60dB, 61dB, 60dB, 59dB, 58dB, 58dB.
Can find out that the signal to noise ratio maximum FM_SN_Best of the FM broadcast singal that receives is 61dB, corresponding D class power amplifier PWM frequency values D_PWM_Best is 560KHz.
Through above-mentioned processing, microcontroller is according to the frequency with the FM receiver module, and the PWM frequency values of best D class power amplifier is set, thus D class power amplifier is reduced to the electromagnetic interference of FM receiver module minimum, thereby make the user receive radio broadcasting signal clearly.
Device embodiment
According to embodiments of the invention; A kind of PWM frequency control apparatus of D class power amplifier is provided; Fig. 4 is the structural representation of PWM frequency control apparatus of the D class power amplifier of the embodiment of the invention; As shown in Figure 4, comprise according to the PWM frequency control apparatus of the D class power amplifier of the embodiment of the invention: signal to noise ratio acquisition module 40, best PWM frequency acquisition module 42, PWM frequency setting module 44, below each module of the embodiment of the invention is carried out detailed explanation.
Particularly, signal to noise ratio acquisition module 40 is used for D class power amplifier is set gradually different PWM frequencies, under the different PWM frequency of D class power amplifier, obtains the signal to noise ratio of the FM broadcast singal that frequency modulation(FM) FM receiver module receives successively;
Best PWM frequency acquisition module 42 is used for obtaining the pairing PWM frequency values of signal to noise ratio maximum of signal to noise ratio, with the PWM frequency values as best PWM frequency;
PWM frequency setting module 44, being used for best PWM frequency configuration is the PWM frequency of D class power amplifier.
Preferably; PWM frequency control apparatus according to the D class power amplifier of the embodiment of the invention also comprises: variable is provided with module; Be used to be provided with variable and with initialization of variable; Wherein, variable comprises: first variable, peaked second variable of storage signal to noise ratio, the ternary of the current signal to noise ratio of storage and the 4th variable of storing current PWM frequency of storing best PWM frequency.
Signal to noise ratio acquisition module 40 specifically is used for: the 4th variable is set to current PWM frequency values; Control FM receiver module receives the FM signal broadcasting; Obtain the snr value under the current PWM frequency from the FM receiver module; Snr value is stored in the ternary.
Best PWM frequency acquisition module 42 specifically is used for: the size of the ternary and second variable relatively, if the value of ternary greater than second variable, then the value with ternary stores second variable into, stores the value of the 4th variable into first variable; If the value of ternary less than second variable, then keeps the value of value and second variable of first variable constant; Make the 4th variable=current PWM frequency values+predetermined steps long value, and judge that the 4th variable whether greater than the power maximum that is provided with in advance, if be judged as is, then obtain the PWM frequency values in first variable,, then call the signal to noise ratio acquisition module if be judged as not.
PWM frequency setting module 44 specifically is used for: with the PWM frequency configuration of D class power amplifier is the value of first variable.
Below in conjunction with accompanying drawing, the technique scheme of the embodiment of the invention is elaborated.
In this example, suppose that the PWM frequency values scope of the D class power amplifier that this handheld terminal adopts is 500KHz～600KHz, step-length 10KHz.
Fig. 3 is the flow chart of detailed process of PWM control method for frequency of the D class power amplifier of the embodiment of the invention, and is as shown in Figure 3, comprises following processing:
Step 1, variable are provided with module 4 variablees are set, and carry out initialization: wherein, 4 variablees are specially:
D_PWM_Best=500KHz, this variable are used to store the PWM frequency values of best D class power amplifier;
FM_SN_Best=0dB, this variable are used to store the maximum of the signal to noise ratio of the FM broadcast singal that receives;
D_PWM=500KHz, this variable are used to store the PWM frequency values of current D class power amplifier;
FM_SN=0dB, this variable are used to store the signal to noise ratio of current FM broadcast singal.
It is D_PWM that step 2, the signal to noise ratio acquisition module 40 of microcontroller are provided with D class power amplifier PWM frequency values, and sends to receive to instruct and receive the FM broadcast singal for the FM receiver module, and the signal to noise ratio of redispatching query statement is given the FM receiver module.After the signal to noise ratio acquisition module 40 of microcontroller is received the signal to noise ratio numerical value that the FM receiver module returns, with the signal to noise ratio value storage to the FM_SN variable;
Step 3, best PWM frequency acquisition module 42 compares the size of FM_SN and FM_SN_Best, if FM_SN more than or equal to FM_SN_Best, then makes D_PWM_Best=D_PWM, FM_SN_Best=FM_SN;
Step 4, best PWM frequency acquisition module 42 calculates D_PWM=D_PWM+10K, if D_PWM smaller or equal to 600KHz, then repeating step 2, step 3 and step 4;
The PWM frequency values that step 5, the PWM frequency setting module 44 of microcontroller are provided with D class power amplifier is D_PWM_Best, finishes.
According to above-mentioned steps, can obtain data as shown in table 1:
Table 1
D class power amplifier PWM frequency values The signal to noise ratio of FM broadcast singal
500KHz 60dB
510KHz 58dB
520KHz 58dB
530KHz 59dB
540KHz 59dB
550KHz 60dB
560KHz 61dB
570KHz 60dB
580KHz 59dB
590KHz 58dB
600KHz 58dB
PWM frequency values scope at D class power amplifier is 500KHz～600KHz; Under the situation of step-length 10KHz; Can find out that from last table microcontroller sets gradually D class power amplifier PWM frequency values and is: 500KHz, 510KHz, 520KHz, 530KHz, 540KHz, 550KHz, 560KHz, 570KHz, 580KHz, 590KHz, 600KHz.
The FM receiver module is under the situation of the different PWM frequency values of D class power amplifier, and the signal to noise ratio of the FM broadcast singal that receives is followed successively by: 60dB, 58dB, 58dB, 59dB, 59dB, 60dB, 61dB, 60dB, 59dB, 58dB, 58dB.
Can find out that the signal to noise ratio maximum FM_SN_Best of the FM broadcast singal that receives is 61dB, corresponding D class power amplifier PWM frequency values D_PWM_Best is 560KHz.
In sum; The embodiment of the invention is through setting gradually the PWM frequency of D class power amplifier; Under the different PWM frequency of D class power amplifier; Obtain the signal to noise ratio of the FM broadcast singal that receives of FM receiver module, and select the PWM frequency values of the pairing D class of signal to noise ratio maximum power amplifier, as the PWM frequency values of best D class power amplifier.Solved in the prior art D class power amplifier FM receiver module has been produced electromagnetic interference; Thereby make the user can't receive the problem of radio broadcasting signal clearly; When the FM receiver module converted the FM broadcast singal into voice signal, the operating frequency that microcontroller is current according to the FM receiver module found the PWM frequency values of best D class power amplifier to carry out sound playing; Thereby D class power amplifier is reduced to minimum to the electromagnetic interference of FM receiver module, make the user can receive radio broadcasting signal clearly.
Although be the example purpose, the preferred embodiments of the present invention are disclosed, it also is possible those skilled in the art will recognize various improvement, increase and replacement, therefore, scope of the present invention should be not limited to the foregoing description.

Claims (10)

1. the pulse width modulation (PWM) control method for frequency of a D class power amplifier is characterized in that, comprising:
D class power amplifier is set gradually different PWM frequencies;
Under the different PWM frequency of said D class power amplifier, obtain the signal to noise ratio of the FM broadcast singal that frequency modulation(FM) FM receiver module receives successively;
Obtain the pairing PWM frequency values of signal to noise ratio maximum in the said signal to noise ratio, with said PWM frequency values as best PWM frequency, and with the said best PWM frequency configuration PWM frequency that is said D class power amplifier.
2. the method for claim 1 is characterized in that, said method also comprises:
Variable is set and with said initialization of variable; Wherein, said variable comprises: first variable, peaked second variable of the said signal to noise ratio of storage, the ternary of the current signal to noise ratio of storage and the 4th variable of storing current PWM frequency of storing said best PWM frequency.
3. method as claimed in claim 2 is characterized in that, under the different PWM frequency of said D class power amplifier, the signal to noise ratio of obtaining the FM broadcast singal that frequency modulation(FM) FM receiver module receives successively specifically comprises:
Step 1, said the 4th variable is set to current PWM frequency values;
Step 2 is controlled said FM receiver module and is received the FM signal broadcasting;
Step 3 is obtained the snr value under the current PWM frequency from said FM receiver module;
Step 4 stores said snr value in the said ternary into.
4. method as claimed in claim 3 is characterized in that, obtains the pairing PWM frequency values of signal to noise ratio maximum in the said signal to noise ratio, and said PWM frequency values is specifically comprised as best PWM frequency:
Step 5, the size of more said ternary and said second variable, if the value of said ternary greater than said second variable, then the value with said ternary stores said second variable into, stores the value of said the 4th variable into said first variable; If the value of said ternary less than said second variable, then keeps the value of value and said second variable of said first variable constant;
Step 6 makes the 4th variable=current PWM frequency values+predetermined steps long value, and judges that whether said the 4th variable is greater than the power maximum that is provided with in advance; If be judged as be; Then obtain the PWM frequency values in said first variable, if be judged as not, then execution in step 1.
5. method as claimed in claim 4 is characterized in that, the PWM frequency that is said D class power amplifier with said best PWM frequency configuration specifically comprises:
With the PWM frequency configuration of said D class power amplifier is the value in said first variable.
6. the pulse width modulation (PWM) frequency control apparatus of a D class power amplifier is characterized in that, comprising:
The signal to noise ratio acquisition module is used for D class power amplifier is set gradually different PWM frequencies, under the different PWM frequency of said D class power amplifier, obtains the signal to noise ratio of the FM broadcast singal that frequency modulation(FM) FM receiver module receives successively;
Best PWM frequency acquisition module is used for obtaining the pairing PWM frequency values of signal to noise ratio maximum of said signal to noise ratio, with said PWM frequency values as best PWM frequency;
The PWM frequency setting module, the PWM frequency that to be used for said best PWM frequency configuration be said D class power amplifier.
7. device as claimed in claim 6 is characterized in that, said device also comprises:
Variable is provided with module; Be used to be provided with variable and with said initialization of variable; Wherein, said variable comprises: first variable, peaked second variable of the said signal to noise ratio of storage, the ternary of the current signal to noise ratio of storage and the 4th variable of storing current PWM frequency of storing said best PWM frequency.
8. device as claimed in claim 7 is characterized in that, said signal to noise ratio acquisition module specifically is used for: said the 4th variable is set to current PWM frequency values; Control said FM receiver module and receive the FM signal broadcasting; Obtain the snr value under the current PWM frequency from said FM receiver module; Said snr value is stored in the said ternary.
9. device as claimed in claim 8; It is characterized in that; Said best PWM frequency acquisition module specifically is used for: the size of more said ternary and said second variable; If the value of said ternary is greater than said second variable, then the value with said ternary stores said second variable into, stores the value of said the 4th variable into said first variable; If the value of said ternary less than said second variable, then keeps the value of value and said second variable of said first variable constant; Make the 4th variable=current PWM frequency values+predetermined steps long value; And judge that said the 4th variable whether greater than the power maximum that is provided with in advance, is then to obtain the PWM frequency values in said first variable if be judged as; If be judged as not, then call said signal to noise ratio acquisition module.
10. device as claimed in claim 9 is characterized in that, said PWM frequency setting module specifically is used for: with the PWM frequency configuration of said D class power amplifier is the value of said first variable.
CN2011103708136A 2011-11-21 2011-11-21 PWM frequency control method for class-D power amplifiers and device adopting same Pending CN102510274A (en)

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PCT/CN2012/071216 WO2013075413A1 (en) 2011-11-21 2012-02-16 Pwm frequency control method and device for d-class power amplifier

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CN103780996B (en) * 2014-02-20 2018-10-02 深圳市京泉华科技股份有限公司 It is a kind of to eliminate circuit of the Switching Power Supply to the sound equipment AM noises generated
CN110572592A (en) * 2019-09-27 2019-12-13 深圳市掌锐电子有限公司 Anti-interference method and device for simultaneous working of high-definition automobile data recorder and FM (frequency modulation)
WO2023220861A1 (en) * 2022-05-16 2023-11-23 Techtronic Cordless Gp Radio and radio circuit including dual controllers
CN115483944A (en) * 2022-09-01 2022-12-16 浙江吉利控股集团有限公司 PWM control method, device, vehicle and storage medium
CN115483944B (en) * 2022-09-01 2023-12-05 浙江吉利控股集团有限公司 PWM control method and device, vehicle and storage medium

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