CN101977025A - Method and device for eliminating noise in class-D power amplifier - Google Patents
Method and device for eliminating noise in class-D power amplifier Download PDFInfo
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- CN101977025A CN101977025A CN 201010527789 CN201010527789A CN101977025A CN 101977025 A CN101977025 A CN 101977025A CN 201010527789 CN201010527789 CN 201010527789 CN 201010527789 A CN201010527789 A CN 201010527789A CN 101977025 A CN101977025 A CN 101977025A
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Abstract
The invention relates to a method and a device for eliminating noise in a class-D power amplifier. The class-D power amplifier comprises an integrator, a triangular wave generator, comparators, a driving stage, an output stage and a feedback network. In the invention, the triangular wave generator is adopted to generate a triangular wave, and an adjustable delay circuit is adopted to delay the triangular wave and respectively input the delayed triangular wave and the original triangular wave to the input ends of the two comparators; or two independent triangular wave generators are adopted to generate two independent triangular waves, the adjustable delay circuit is arranged behind one of the triangular wave generators so as to generate a delayed triangular wave, and the delayed triangular wave and the triangular wave generated by the other triangular wave generator are applied to the input ends of the two comparators together, thus the two output ends of the class-D power amplifier generate delays, so that certain effective signals are held on a load when output pulse signals are switched. The invention can effectively restrain or eliminate the noise generated at the output ends of the class-D power amplifier, and ensure the class-D power amplifier to maintain smaller quiescent current.
Description
Technical field
The present invention be more particularly directed to a kind of method and device of in the D power-like amplifier, eliminating noise and reducing quiescent current.
Background technology
D power-like amplifier commonly used at present adopts the same phase structure of fully differential mostly,, comprises integrator, comparator, driving stage, output stage, triangular-wave generator, feedback network etc. that is.Integrator adopts the difference amplifier to cooperate realization with electric capacity usually, the input analog signal is input to the integrator input simultaneously with the output pulse feedback signal, the sawtooth signal that changes with input signal that two phase places of integrator output are opposite, these two signals are added to the input of two comparators, and the triangular wave that produces with triangular-wave generator compares output pulse signal; After this pulse signal strengthens driving force through driving stage, be sent to output stage and carry out power amplification output, the signal of output stage output feeds back to the integrator input through feedback network gain is set.When not having input audio signal, the output pulse signal of two outputs of power amplifier is a same phase, promptly is all high level or is all low level.When audio signal of input, the duty ratio of an output increases according to the amplitude of input signal, and the duty ratio of another output is corresponding to be reduced, and the difference of the duty ratio of two outputs has just reflected real effective output signal.When such most D power-like amplifiers does not have input signal, two output same-phases, can reduce quiescent current like this, but when the output pulse is switched, because when two switching tubes of an output are opened simultaneously or are turn-offed, useful signal in the load is zero, and noise is reflected in output easily, will bring noise into to load like this.
Summary of the invention
The objective of the invention is to propose the method and the device of noise in a kind of D of elimination power-like amplifier, it can suppress or eliminate the noise that D power-like amplifier output produces, and make the D power-like amplifier keep smaller quiescent current, thereby overcome deficiency of the prior art.
For achieving the above object, the present invention has adopted following technical scheme:
A kind of method of eliminating noise in the D power-like amplifier, described D power-like amplifier comprises integrator, triangular-wave generator, comparator, driving stage, output stage and feedback network, behind the integrator receiving inputted signal, export the opposite sawtooth signal that changes with input signal of two phase places, the triangular wave that these two sawtooth signals and triangular-wave generator produce is transfused to after two comparators compare, output pulse signal, after this pulse signal strengthens driving force through driving stage, be sent to output stage and carry out power amplification output, the signal of output stage output feeds back to integrator through feedback network gain is set, it is characterized in that this method is:
(1) in this D power-like amplifier, adopts a triangular-wave generator, after this triangular-wave generator of mat produces triangular wave, with an adjustable delay circuit this triangular wave is postponed to handle, the triangular wave of the triangular wave before then will postponing after postponing adds to the input of two comparators;
(2) or, in this D power-like amplifier, adopt two independent triangular-wave generators, and behind the triangular-wave generator triangular wave that an adjustable delay circuit generation band postpones is set therein, then will add to the input of two comparators with the triangular wave that the triangular wave that postpones produces with another triangular-wave generator;
The operation of mat aforementioned (1) or (2) makes producing a delay between two outputs of D power-like amplifier, keeps being not equal to zero useful signal when output pulse signal is switched in the load, thereby suppresses or eliminate the noise of D power-like amplifier output.
Say that further in this method, the time that produces delay between two outputs of described D power-like amplifier is regulated by described adjustable delay circuit, to reduce the quiescent current of D power-like amplifier.
Described delay circuit adopts electric capacity and/or resistance-capacitance network.
A kind of device of eliminating noise in the D power-like amplifier, comprise the D power-like amplifier, described D power-like amplifier comprises integrator, triangular-wave generator, two comparators, driving stage, output stage and feedback network, behind the integrator receiving inputted signal, export the opposite sawtooth signal that changes with input signal of two phase places, the triangular wave that these two sawtooth signals and triangular-wave generator produce is transfused to after two comparators compare, output pulse signal, after this pulse signal strengthens driving force through driving stage, be sent to output stage and carry out power amplification output, the signal of output stage output feeds back to integrator through feedback network gain is set, and it is characterized in that:
Described triangular-wave generator is one, this triangular-wave generator is connected with comparator through an adjustable delay circuit, after the delayed processing of circuit of triangular wave that this triangular-wave generator produces, triangular wave before postponing adds to the input of two comparators, produce a delay between two outputs of D power-like amplifier thereby make, keep being not equal to zero useful signal when output pulse signal is switched in the load;
Or, described triangular-wave generator is two independently triangular-wave generators, one adjustable delay circuit wherein is set to produce the triangular wave that band postpones behind the triangular-wave generator, the triangular wave that the triangular wave that this band postpones produces with another triangular-wave generator adds to the input of two comparators, produce a delay between two outputs of D power-like amplifier thereby make, keep being not equal to zero useful signal when output pulse signal is switched in the load.
Particularly, described delay circuit adopts electric capacity and/or resistance-capacitance network.
The time that produces delay between two outputs of described D power-like amplifier is regulated by described adjustable delay circuit, to reduce the quiescent current of D power-like amplifier.
As previously mentioned, when the D power-like amplifier did not have input signal, two output same-phases promptly were all high level or are all low level, can reduce quiescent current like this, but were easy to generate distorted signals when the output pulse is switched, and brought noise into.The present invention can regulate two time of delays between the output for the D power-like amplifier is provided with a variable delay, keeps certain useful signal in the load when output pulse signal is switched, and reduces noise.
Postpone among the present invention to be added in before the comparator, can adopt a triangular-wave generator to produce triangular wave, adopt a delay circuit that this triangular wave is postponed again after, be added to two comparator input terminals with former triangular wave; Also can adopt two independently triangular-wave generator produce two independently triangular waves, and a triangular-wave generator back increases an adjustable delay generation circuit therein, the triangular wave of delay and the input that another undelayed triangular wave is added to two comparators will be arranged again, finally produce adjustable delay at two outputs of D power-like amplifier, keep certain useful signal in the load when output pulse signal is switched, reduce the noise of output.Further, consider when time of delay is excessive that the quiescent current of D power-like amplifier may increase, the present invention also can regulate output delay time by the parameter of control lag circuit, makes the D power-like amplifier keep smaller quiescent current.
Compared with prior art, beneficial effect of the present invention is: can effectively suppress or eliminate the noise that D power-like amplifier output produces, and make the D power-like amplifier keep smaller quiescent current.
Description of drawings
Fig. 1 is the structural representation of D power-like amplifier in the utility model preferred embodiment;
Fig. 2 is that the D power-like amplifier postpones to produce one of schematic diagram in the utility model preferred embodiment;
Fig. 3 is that the D power-like amplifier postpones to produce two of schematic diagram in the utility model preferred embodiment;
Fig. 4 is during for no input signal, the output waveform schematic diagram of D power-like amplifier in the utility model preferred embodiment;
Fig. 5 when input signal is arranged, the output waveform schematic diagram of D power-like amplifier in the utility model preferred embodiment.
Embodiment
Below in conjunction with accompanying drawing and preferred embodiment technical scheme of the present invention is described further.
The D power-like amplifier comprises first integrator as described in Figure 1, first, second comparator, driving stage, output stage, triangular-wave generator, adjustable delay circuit unit.Described first integrator is made of difference amplifier and first, second capacitor C 1, C2; Described driving stage is by first, second not gate, and the one the second NAND gate constitute; Forward input analog signal and negative sense output pulse feedback signal are input to the in-phase input end of integrator simultaneously, negative sense input analog signal and forward output pulse feedback signal are input to the inverting input of integrator simultaneously, the sawtooth signal A that changes with input signal that two phase places of integrator output are opposite, B; A, B connect the in-phase end of the one the second comparators respectively, and through the signal S1 that the triangular wave generator produces, S1 S2 behind the adjustable delay circuit unit, S1, S2 connect the one the second relatively the end of oppisite phase respectively, and the one the second comparators are output pulse signal C respectively, D; C, D export forward output pulse E and negative sense output pulse F respectively after driving; EF exports loud speaker to through output-stage circuit.
Consult Fig. 1, the structure of present embodiment D power-like amplifier is to commonly use the D power-like amplifier similar, but also comprises the delay circuit unit of scalable time of delay, and possess effective adjusting step-length and adjustable range by register controlled the time of delay of this unit.One of method that realizes is to adopt two triangular-wave generators and an adjustable delay circuit unit (as shown in Figure 2) or a triangular-wave generator and an adjustable delay circuit unit (as shown in Figure 3).
Consult shown in Figure 2, adopt two independently the triangular-wave generator unit produce two independently triangular waves of same frequency respectively, one of them triangular-wave generator output triangular wave S1, behind the triangular wave output process adjustable delay circuit unit of another triangular-wave generator, produce triangular wave S2 through postponing.
Consult shown in Figure 3ly, adopt triangular-wave generator to produce a triangular wave S1, this triangular wave S1 is added to the delay circuit unit and produces a triangular signal S2 that delay is arranged.
Consult Fig. 2～Fig. 3, even using, described delay circuit unit produces the triangular signal S2 that arranged time of delay, promptly between S1 and S2, produce a time of delay, through two comparators relatively after, produce a time of delay at two comparator output terminals, finally produce a delay, keep non-vanishing useful signal in the load when output pulse signal is switched, the noise of output is suppressed reduce or eliminates at two outputs of D class A amplifier A.
Consider when time of delay is excessive that the quiescent current of D power-like amplifier can increase, the parameter that present embodiment can the control lag circuit is regulated output delay time, makes the D power-like amplifier keep smaller quiescent current.
The delay circuit unit of present embodiment can adopt multiple mode and circuit structure to realize delay feature.For example, can realize postponing, also can realize postponing, also can realize with other multiple conventional methods by resistance-capacitance network by in circuit, increasing electric capacity.When realizing, adjust time of delay by adjusting capacitance with electric capacity; When using resistance-capacitance network, can adjust time of delay by regulating the resistance capacitance value.
Above-mentioned implementing method not only can be added in S1 among Fig. 1, and the S2 place also can be added in C among Fig. 1, the D place.
Consult Fig. 4, when present embodiment D power-like amplifier does not have the signal input, can can replace output pulse signal at two outputs, the width of pulse just equals the time of delay that adjustable delay circuit of the present invention produces, make total signal that keeps certain amplitude in the output loading, the noise of output just obtains suppressing to reduce.
Consult Fig. 5, when present embodiment D power-like amplifier had input signal, an output output signal duty ratio of D power-like amplifier increased gradually, and other end duty ratio then correspondence reduces gradually; The continuous output pulse signal of an end when input signal is enough big, the other end is then exported the direct current low level.
Mat technology of the present invention can effectively suppress or eliminate the noise that D power-like amplifier output produces, and makes the D power-like amplifier keep smaller quiescent current.
Above-mentioned preferred embodiment only is explanation technical conceive of the present invention and characteristics, and its purpose is to allow the personage who is familiar with this technology can understand content of the present invention and enforcement according to this, can not limit protection scope of the present invention with this.All equivalences that spirit is done according to the present invention change or modify, and all should be encompassed within protection scope of the present invention.
Claims (6)
1. method of eliminating noise in the D power-like amplifier, described D power-like amplifier comprises integrator, triangular-wave generator, comparator, driving stage, output stage and feedback network, behind the integrator receiving inputted signal, export the opposite sawtooth signal that changes with input signal of two phase places, the triangular wave that these two sawtooth signals and triangular-wave generator produce is transfused to after two comparators compare, output pulse signal, after this pulse signal strengthens driving force through driving stage, be sent to output stage and carry out power amplification output, the signal of output stage output feeds back to integrator through feedback network gain is set, it is characterized in that this method is:
(1) in this D power-like amplifier, adopts a triangular-wave generator, after this triangular-wave generator of mat produces triangular wave, with an adjustable delay circuit this triangular wave is postponed to handle, the triangular wave of the triangular wave before then will postponing after postponing adds to the input of two comparators;
(2) or, in this D power-like amplifier, adopt two independent triangular-wave generators, and behind the triangular-wave generator triangular wave that an adjustable delay circuit generation band postpones is set therein, then will add to the input of two comparators with the triangular wave that the triangular wave that postpones produces with another triangular-wave generator;
The operation of mat aforementioned (1) or (2) makes producing a delay between two outputs of D power-like amplifier, keeps being not equal to zero useful signal when output pulse signal is switched in the load, thereby suppresses or eliminate the noise of D power-like amplifier output.
2. the method for noise in the elimination D power-like amplifier according to claim 1, it is characterized in that, in this method, the time that produces delay between two outputs of described D power-like amplifier is regulated by described adjustable delay circuit, to reduce the quiescent current of D power-like amplifier.
3. the method for noise is characterized in that described delay circuit adopts electric capacity and/or resistance-capacitance network in the elimination D power-like amplifier according to claim 1 and 2.
4. device of eliminating noise in the D power-like amplifier, comprise the D power-like amplifier, described D power-like amplifier comprises integrator, triangular-wave generator, two comparators, driving stage, output stage and feedback network, behind the integrator receiving inputted signal, export the opposite sawtooth signal that changes with input signal of two phase places, the triangular wave that these two sawtooth signals and triangular-wave generator produce is transfused to after two comparators compare, output pulse signal, after this pulse signal strengthens driving force through driving stage, be sent to output stage and carry out power amplification output, the signal of output stage output feeds back to integrator through feedback network gain is set, and it is characterized in that:
Described triangular-wave generator is one, this triangular-wave generator is connected with comparator through an adjustable delay circuit, after the delayed processing of circuit of triangular wave that this triangular-wave generator produces, triangular wave before postponing adds to the input of two comparators, produce a delay between two outputs of D power-like amplifier thereby make, keep being not equal to zero useful signal when output pulse signal is switched in the load;
Or, described triangular-wave generator is two independently triangular-wave generators, one adjustable delay circuit wherein is set to produce the triangular wave that band postpones behind the triangular-wave generator, the triangular wave that the triangular wave that this band postpones produces with another triangular-wave generator adds to the input of two comparators, produce a delay between two outputs of D power-like amplifier thereby make, keep being not equal to zero useful signal when output pulse signal is switched in the load.
5. the device of noise is characterized in that described delay circuit adopts electric capacity and/or resistance-capacitance network in the elimination D power-like amplifier as claimed in claim 4.
6. the device of noise in the elimination D power-like amplifier as claimed in claim 4, it is characterized in that, the time that produces delay between two outputs of described D power-like amplifier is regulated by described adjustable delay circuit, to reduce the quiescent current of D power-like amplifier.
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| CN 201010527789 CN101977025A (en) | 2010-11-02 | 2010-11-02 | Method and device for eliminating noise in class-D power amplifier |
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| CN 201010527789 CN101977025A (en) | 2010-11-02 | 2010-11-02 | Method and device for eliminating noise in class-D power amplifier |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103490734A (en) * | 2013-07-26 | 2014-01-01 | 江苏科技大学 | Device for canceling input-stage thermal noise of resistive feedback power current amplifier |
| CN103516315A (en) * | 2013-07-26 | 2014-01-15 | 江苏科技大学 | Device for offsetting passive feedback network noise |
| CN105703717A (en) * | 2014-11-24 | 2016-06-22 | 上海贝岭股份有限公司 | Explosion sound suppression circuit and method |
| CN107438962A (en) * | 2015-03-30 | 2017-12-05 | 高通股份有限公司 | Power supply inhibiting rate is improved by noise cancellation in audio-frequency amplifier loop |
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| CN1642001A (en) * | 2003-11-26 | 2005-07-20 | 雅马哈株式会社 | Class-D amplifier |
| CN101369802A (en) * | 2007-08-16 | 2009-02-18 | 美国芯源系统股份有限公司 | Closed-loop D-class power amplifier and its control method |
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2010
- 2010-11-02 CN CN 201010527789 patent/CN101977025A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1642001A (en) * | 2003-11-26 | 2005-07-20 | 雅马哈株式会社 | Class-D amplifier |
| CN101369802A (en) * | 2007-08-16 | 2009-02-18 | 美国芯源系统股份有限公司 | Closed-loop D-class power amplifier and its control method |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103490734A (en) * | 2013-07-26 | 2014-01-01 | 江苏科技大学 | Device for canceling input-stage thermal noise of resistive feedback power current amplifier |
| CN103516315A (en) * | 2013-07-26 | 2014-01-15 | 江苏科技大学 | Device for offsetting passive feedback network noise |
| CN103516315B (en) * | 2013-07-26 | 2015-12-23 | 江苏科技大学 | A kind of device of offsetting passive feedback network noise |
| CN103490734B (en) * | 2013-07-26 | 2016-01-20 | 江苏科技大学 | A kind of device of offsetting resistive feedback power current amplifier input stage thermal noise |
| CN105703717A (en) * | 2014-11-24 | 2016-06-22 | 上海贝岭股份有限公司 | Explosion sound suppression circuit and method |
| CN105703717B (en) * | 2014-11-24 | 2019-04-12 | 上海贝岭股份有限公司 | Explosion sound suppression circuit and method |
| CN107438962A (en) * | 2015-03-30 | 2017-12-05 | 高通股份有限公司 | Power supply inhibiting rate is improved by noise cancellation in audio-frequency amplifier loop |
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Inventor after: Fan Mao Inventor after: Wu Qing Inventor after: Lin Kun Inventor before: Fan Mao |
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Application publication date: 20110216 |