CN115333495A - Audio amplifier and related device - Google Patents

Audio amplifier and related device Download PDF

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CN115333495A
CN115333495A CN202110506666.4A CN202110506666A CN115333495A CN 115333495 A CN115333495 A CN 115333495A CN 202110506666 A CN202110506666 A CN 202110506666A CN 115333495 A CN115333495 A CN 115333495A
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voltage
output
output voltage
audio amplifier
circuit
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胡孔生
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Shanghai Awinic Technology Co Ltd
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Shanghai Awinic Technology Co Ltd
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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

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Abstract

The application discloses audio amplifier and relevant device includes: the circuit comprises a preamplifier, an integrator, a pulse width modulation circuit, a common-mode reference voltage modulator and an output stage circuit; and the common-mode reference voltage modulator is used for outputting a first common-mode reference voltage according to the first output voltage and the second output voltage when the first output voltage or the second output voltage output by the integrator is greater than the direct-current reference level, so that the first output voltage and the second output voltage are less than or equal to the direct-current reference level. In the audio amplifier provided by the embodiment of the application, when the first output voltage or the second output voltage is greater than the dc reference level, the first common mode reference voltage is adjusted so that the first output voltage and the second output voltage are less than or equal to the dc reference level. Therefore, the first common mode reference voltage of the audio amplifier provided by the embodiment of the application can be larger than half of the analog power supply voltage, and the overall power consumption of the LC filter application circuit connected with the audio amplifier is reduced.

Description

Audio amplifier and related device
Technical Field
The present application relates to the field of electronic circuits, and more particularly, to an audio amplifier and related apparatus.
Background
The audio amplifier generally includes: the amplifier comprises a preamplifier, an integrator, a common-mode reference voltage modulator and an output stage circuit. The pre-stage amplifier is used for amplifying the received differential signal; the integrator is used for amplifying the differential signal output by the preamplifier and outputting the differential signal to the pulse width modulation circuit; the pulse width modulation circuit is used for modulating the received differential signal and outputting an output signal; and the output stage circuit is used for improving the driving capability of the output signal.
Currently, in an audio amplifier, in order to completely output an input signal, a common mode reference voltage is half of an analog power supply voltage, so that a duty ratio of a square wave signal output by the audio amplifier is fixed to 50%. The power consumption of the LC filter application circuit connected with the audio amplifier is in direct proportion to the duty ratio of the square wave signal output by the audio amplifier, and the power consumption of the LC filter application circuit connected with the audio amplifier is higher due to the fact that the duty ratio of the square wave signal output by the audio amplifier is higher.
Disclosure of Invention
In order to solve the above technical problem, the present application provides an audio amplifier and a related apparatus for reducing power consumption of an LC filter application circuit connected to the audio amplifier.
In order to achieve the above purpose, the technical solutions provided in the embodiments of the present application are as follows:
an embodiment of the present application provides an audio amplifier, including: the circuit comprises a preamplifier, an integrator, a pulse width modulation circuit, a common-mode reference voltage modulator and an output stage circuit;
the first input end and the second input end of the common mode reference voltage modulator are respectively connected with the first output end and the second output end of the integrator, and the output end of the common mode reference voltage modulator is connected with the first input end of the integrator;
the common mode reference voltage modulator is used for outputting a first common mode reference voltage to the first input end of the integrator according to the first output voltage and the second output voltage when at least one of the first output voltage of the first output end of the integrator and the second output voltage of the second output end of the integrator is larger than a direct current reference level, so that the first output voltage and the second output voltage are smaller than or equal to the direct current reference level.
Optionally, the common-mode reference voltage modulator is further configured to output a fixed second common-mode reference voltage to the first input terminal of the integrator when the first output voltage and the second output voltage are both smaller than the dc reference level; the fixed second common-mode reference voltage is greater than half of the analog supply voltage.
Optionally, the common mode reference voltage modulator includes:
the comparison circuit and the current-to-voltage circuit;
the comparison circuit is used for generating a first current according to the first output voltage and the second output voltage when the first output voltage is greater than a direct current reference level or the second output voltage is greater than the direct current reference level;
the current-to-voltage circuit is configured to output the first common-mode reference voltage to a first input terminal of the integrator according to the fixed second common-mode reference voltage and the first current.
Optionally, the comparison circuit is specifically configured to, when the first output voltage is greater than the dc reference level, positively correlate the magnitude of the first current with a difference between the dc reference level and the first output voltage;
when the second output voltage is greater than the DC reference level, the magnitude of the first current is positively correlated with the difference between the DC reference level and the second output voltage.
Optionally, the current-to-voltage circuit includes:
an operational amplifier and a resistor;
the positive input end of the operational amplifier is connected with the fixed second common mode reference voltage; the negative input end of the operational amplifier is connected with the output end of the operational amplifier; the first end of the resistor is connected with the output end of the operational amplifier, and the second end of the resistor is connected with the first output current output by the output end of the comparison circuit and connected with the first input end of the integrator.
Optionally, when the first output voltage is greater than the dc reference level, a voltage across the resistor is equal to a difference between the dc reference level and the first output voltage;
when the second output voltage is greater than the dc reference level, the voltage across the resistor is equal to the difference between the dc reference level and the second output voltage.
Optionally, the pulse width modulation circuit includes: the device comprises a first modulation comparator, a second modulation comparator and a triangular wave generating circuit;
the first modulation comparator is used for outputting a first modulation square wave according to the first output voltage and the triangular wave voltage generated by the triangular wave generating circuit;
the second modulation comparator is used for outputting a second modulation square wave according to the second output voltage and the triangular wave voltage generated by the triangular wave generating circuit;
the direct current reference level is greater than the maximum value of the triangular wave voltage.
Optionally, a difference between the maximum value of the triangular wave voltage and the dc reference level is determined by maximum voltage ripple amplitudes of the first output voltage and the second output voltage.
Optionally, an average value of the first output voltage and the second output voltage is the first common mode reference voltage or the fixed second common mode reference voltage.
Optionally, the output stage circuit includes:
a gate drive circuit and a power tube circuit.
The embodiment of the application also provides a sound box, which comprises the audio amplifier, an LC filter application circuit and a loudspeaker;
the audio amplifier is connected with the first end of the LC filter application circuit, and the second end of the LC filter application circuit is connected with the loudspeaker.
According to the technical scheme, the method has the following beneficial effects:
the embodiment of the present application provides an audio amplifier, which includes: the circuit comprises a preamplifier, an integrator, a pulse width modulation circuit, a common-mode reference voltage modulator and an output stage circuit; the first input end and the second input end of the common-mode reference voltage modulator are respectively connected with the first output end and the second output end of the integrator, and the output end of the common-mode reference voltage modulator is connected with the first input end of the integrator; and the common-mode reference voltage modulator is used for outputting a first common-mode reference voltage to the first input end of the integrator according to the first output voltage and the second output voltage when at least one of the first output voltage at the first output end of the integrator and the second output voltage at the second output end of the integrator is greater than the direct-current reference level, so that the first output voltage and the second output voltage are less than or equal to the direct-current reference level.
As can be seen from the above, in the audio amplifier provided in the embodiments of the present application, when the first output voltage or the second output voltage is greater than the dc reference level, the first common mode reference voltage is adjusted to make the first output voltage and the second output voltage less than or equal to the dc reference level. Therefore, under the condition of ensuring complete output of signals, the first common-mode reference voltage of the audio amplifier provided by the embodiment of the application can be larger than half of the voltage of the analog power supply, so that the average duty ratio of the audio amplifier is smaller than 50%, and the overall power consumption of an LC filter application circuit connected with the audio amplifier is reduced.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
Fig. 1 is a schematic structural diagram of an audio amplifier according to an embodiment of the present disclosure;
fig. 2 is a circuit diagram of an audio amplifier according to an embodiment of the present application;
fig. 3 is a schematic structural diagram of a common mode reference voltage modulator according to an embodiment of the present disclosure;
FIG. 4 is a circuit diagram of a common mode reference voltage modulator according to an embodiment of the present application;
fig. 5 is a signal diagram of an audio amplifier operating in a full-wave modulation mode according to an embodiment of the present application;
fig. 6 is a signal diagram of an audio amplifier operating in a single-side modulation mode according to an embodiment of the present application;
fig. 7 is a circuit diagram of an LC filter application circuit according to an embodiment of the present application;
fig. 8 is a line graph of inductor current in an LC filter application circuit according to an embodiment of the present application.
Detailed Description
In order to help better understand the scheme provided in the embodiment of the present application, before the method provided in the embodiment of the present application is introduced, a scenario of an application of the scheme in the embodiment of the present application is introduced.
Currently, in an audio amplifier, in order to completely output an input signal, a common mode reference voltage is half of an analog power supply voltage, so that a duty ratio of a square wave signal output by the audio amplifier is fixed to 50%. The power consumption of the LC filter application circuit connected with the audio amplifier is in direct proportion to the duty ratio of the square wave signal output by the audio amplifier, and the power consumption of the LC filter application circuit connected with the audio amplifier is higher due to the fact that the duty ratio of the square wave signal output by the audio amplifier is higher.
In order to solve the above technical problem, an embodiment of the present application provides an audio amplifier, including: the circuit comprises a preamplifier, an integrator, a pulse width modulation circuit, a common-mode reference voltage modulator and an output stage circuit; a pre-amplifier for amplifying the received differential signal; the integrator is used for amplifying the differential signal output by the preamplifier and outputting the differential signal to the pulse width modulation circuit; the pulse width modulation circuit is used for modulating the received differential signal and outputting an output signal; the output stage circuit is used for improving the driving capability of the output signal; the first input end and the second input end of the common mode reference voltage modulator are respectively connected with the first output end and the second output end of the integrator, and the output end of the common mode reference voltage modulator is connected with the first input end of the integrator; the common-mode reference voltage modulator is used for outputting a first common-mode reference voltage to the first input end of the integrator according to the first output voltage and the second output voltage when at least one of the first output voltage at the first output end of the integrator and the second output voltage at the second output end of the integrator is greater than the direct current reference level, so that the first output voltage and the second output voltage are less than or equal to the direct current reference level; when the first output voltage and the second output voltage are both smaller than the direct current reference level, outputting a fixed second common mode reference voltage to a first input end of the integrator; the fixed second common-mode reference voltage is greater than half of the analog supply voltage.
As can be seen from the above, when the voltage output by the integrator is greater than the dc reference level, the fixed second common-mode reference voltage is greater than half of the analog power supply voltage, so that the duty ratio of the square wave signal output by the audio amplifier is less than 50%. When the voltage output by the integrator is greater than the direct current reference level, in order to completely output the input signal, the first common mode reference voltage is adjusted so that the voltage output by the integrator is less than or equal to the direct current reference level, and the duty ratio of the square wave signal output by the audio amplifier is usually less than 50%. Therefore, the duty ratio of the audio amplifier provided by the embodiment of the present application is usually less than 50%, and since the power consumption of the LC filter application circuit connected to the audio amplifier is in direct proportion to the duty ratio of the square wave signal output by the audio amplifier, the overall power consumption of the LC filter application circuit connected to the audio amplifier is reduced by the audio amplifier provided by the embodiment of the present application.
In order to make the aforementioned objects, features and advantages of the present application more comprehensible, embodiments accompanying the drawings are described in detail below.
Referring to fig. 1, a schematic diagram of an audio amplifier according to an embodiment of the present disclosure is shown. As shown in fig. 1, an audio amplifier provided in an embodiment of the present application includes: a preamplifier 100, an integrator 200, a pulse width modulation circuit 300, an output stage circuit 400 and a common mode reference voltage modulator 500;
a first input end and a second input end of the common mode reference voltage modulator 500 are respectively connected with a first output end and a second output end of the integrator 200, and an output end of the common mode reference voltage modulator 500 is connected with the first input end of the integrator 200;
a common mode reference voltage modulator 500, configured to output a first common mode reference voltage to a first input terminal of the integrator 200 according to a first output voltage and a second output voltage when the first output voltage at a first output terminal of the integrator 200 or the second output voltage at a second output terminal of the integrator 200 is greater than a dc reference level, so that the first output voltage and the second output voltage are less than or equal to the dc reference level; when the first output voltage and the second output voltage are both smaller than the dc reference level, outputting a fixed second common mode reference voltage to the first input terminal of the integrator 200; the fixed second common-mode reference voltage is greater than half of the analog supply voltage.
It should be noted that, in the embodiment of the present application, the preamplifier 100 is configured to amplify the received differential signal; an integrator 200 for amplifying the differential signal output from the preamplifier and outputting the amplified signal to the pwm circuit; the pulse width modulation circuit 300 is configured to modulate the received differential signal and output an output signal; the output stage circuit 400 is configured to improve the driving capability of the output signal.
It can be understood that, in the embodiment of the present application, by making the first common-mode reference voltage and the fixed second common-mode reference voltage greater than half of the analog power supply voltage when the audio amplifier is in a static state, the duty ratio of the square wave signal output by the audio amplifier is less than 50%, and since the power consumption of the LC filter application circuit connected to the audio amplifier is in a direct proportion relationship with the duty ratio of the square wave signal output by the audio amplifier, the audio amplifier provided in the embodiment of the present application reduces the overall power consumption of the LC filter application circuit connected to the audio amplifier.
On the other hand, when the voltage output by the integrator is greater than the direct current reference level, in order to enable the input signal to be completely output, the first common mode reference voltage is adjusted to enable the voltage output by the integrator to be less than or equal to the direct current reference level, and the duty ratio of the square wave signal output by the audio amplifier is fixed to be smaller than 50% compared with the traditional full-wave modulation on the whole, so that the overall power consumption of an LC filter application circuit connected with the audio amplifier is further reduced.
In summary, in the audio amplifier provided in the embodiments of the present application, when the first output voltage or the second output voltage is greater than the dc reference level, the first common mode reference voltage is adjusted to make the first output voltage and the second output voltage less than or equal to the dc reference level. Therefore, under the condition of ensuring complete output of signals, the first common-mode reference voltage of the audio amplifier provided by the embodiment of the application can be larger than half of the voltage of the analog power supply, so that the average duty ratio of the audio amplifier is smaller than 50%, and the overall power consumption of an LC filter application circuit connected with the audio amplifier is reduced. The audio amplifier provided by the embodiment of the present application is described below by a specific embodiment:
referring to fig. 2, the circuit diagram of an audio amplifier provided in the embodiment of the present application is shown. As shown in fig. 2, an audio amplifier provided in an embodiment of the present application includes: a preamplifier 100, an integrator 200, a pulse width modulation circuit 300, and a common mode reference voltage modulator 500;
the preamplifier 100 includes: the circuit comprises a capacitor C1, a resistor R1, an adjustable resistor RF1 and a fully differential operational amplifier Amp1. The first end of the C1 is connected with the output differential signal, the second end of the C1 is connected with the first input end of the Amp1 through the R1, and the first output end of the Amp1 is connected with the first input end of the Amp1 through the RF 1. Since the circuit provided in the embodiment of the present application is a differential circuit, and the connection manner of the circuit connected to the second input terminal of the Amp1 is similar to that of the first input terminal of the Amp1, this application is not described herein again. The voltage output by the first output end of the Amp1 is VON1, and the voltage output by the second output end of the Amp1 is VOP1.
The integrator 200 includes: a resistor R2, a resistor RF2, a capacitor CF2 and a fully differential operational amplifier Amp1. The first end of R2 is connected with the output end of Amp1 in the preamplifier, the second end of R2 is connected with the first input end of Amp2, the first output end of Amp2 is connected with the first input end of Amp2 through CF2, and the first input end of Amp2 is connected with the first output end of the pulse width modulation circuit 300 through RF 2. Since the circuit provided in the embodiment of the present application is a fully differential circuit, the connection mode of the circuit connected to the second input terminal of the Amp2 is similar to that of the first input terminal of the Amp2, which is not described herein again. The voltage output by the first output end of the Amp2 is VON2, and the voltage output by the second output end of the Amp2 is VOP2.
The pulse width modulation circuit 300 includes: the first modulation comparator comp1, the second modulation comparator comp2 and the triangular wave generating circuit RAMP; the first modulation comparator comp1 is used for outputting a first modulation square wave VON according to the first output voltage and the triangular wave voltage generated by the triangular wave generating circuit RAMP; the second modulation comparator comp2 is used for outputting a second modulation square wave VOP according to a second output voltage and a triangular wave voltage generated by the triangular wave generating circuit RAMP; wherein the DC reference level is greater than the maximum value of the triangular wave voltage.
The common mode reference voltage modulator 500 in the embodiment of the present application is specifically described as follows:
referring to fig. 3, the figure is a schematic structural diagram of a common mode reference voltage modulator according to an embodiment of the present application. As shown in fig. 3, the common mode reference voltage modulator provided in the embodiment of the present application includes:
a comparison circuit 301 and a current-to-voltage circuit 302;
a comparison circuit 301, configured to generate a first current I1 according to the first output voltage VON2 and the second output voltage VOP2 when the first output voltage VON2 is greater than the dc reference level VL or the second output voltage VOP2 is greater than the dc reference level VL;
the current-to-voltage circuit 302 is configured to output a first common mode reference voltage VCOM2 to a first input terminal of the integrator 200 according to the fixed second common mode reference voltage VC and the first current I1.
It can be understood that, when the first output voltage VON2 is greater than the dc reference level VL or the second output voltage VOP2 is greater than the dc reference level VL, the comparison circuit 301 generates the first current I1 according to the first output voltage VON2 and the second output voltage VOP2. In the embodiment of the application, when the first output voltage is greater than the dc reference level, the magnitude of the first current is positively correlated with the difference between the dc reference level and the first output voltage; when the second output voltage is greater than the dc reference level, the magnitude of the first current is positively correlated with the difference between the dc reference level and the second output voltage.
The current-to-voltage circuit 302 is configured to output a first common-mode reference voltage VCOM2 to the first input terminal of the integrator 200 according to the fixed second common-mode reference voltage VC and the first current I1, so that the first output voltage VON2 and the second output voltage VOP2 output by the integrator 200 are greater than or equal to the dc reference level VL, and further, the input signal can be completely output.
Referring to fig. 4, the figure is a circuit diagram of a common mode reference voltage modulator according to an embodiment of the present application. As shown in fig. 3, the common mode reference voltage modulator provided in the embodiment of the present application includes:
a comparison circuit 301 and a current-to-voltage circuit 302;
the comparison circuit 301 includes: transistor M1, transistor M2, transistor M3, transistor M4, transistor M5, transistor M6, transistor M7, transistor M8, resistor R4, and resistor R5.
The source electrode of the M1 is connected with the source electrode of the M3 through the R4, and the source electrode of the M2 is connected with the source electrode of the M3 through the R5; the grid of M1 is connected with VL, the grid of M2 is connected with VOP2, and the grid of M3 is connected with VON2; the drain electrode of the M1 is connected with the drain electrode of the M4, the drain electrode of the M4 is connected with the grid electrode of the M4, and the source electrode of the M4 is connected with the analog power supply VDD; the drain electrode of M2 and the drain electrode of M3 are both connected with the drain electrode of M5, the grid electrode of M5 is connected with the grid electrode of M4, and the source electrode of M5 is connected with an analog power supply VDD; the drain electrode of M6 is respectively connected with the drain electrode of M5 and the grid electrode of M6, and the source electrode of M6 is connected with an analog power supply VDD; the grid electrode of M7 is connected with the grid electrode of M6, the source electrode of M7 is connected with the analog power supply VDD, the drain electrode of M7 outputs a second current I2, and the second current I2 is the mirror image current of the first current I1.
The current-to-voltage circuit 302 includes: an operational amplifier AMP and a resistor R3;
the positive input end of the operational amplifier AMP is connected with the fixed second common-mode reference voltage; the negative input end of the operational amplifier AMP is connected with the output end of the operational amplifier AMP; a first end of the resistor R3 is connected to the output end of the operational amplifier AMP, and a second end of the resistor R3 is connected to the first output current I1 output by the output end of the comparison circuit 301 and connected to a first input end of the integrator 200.
It should be noted that the current I1 flows through the resistor R3, the voltage at the first end of R3 is equal to VC, and the voltage at the first input end of the integrator 200 connected to the second end of R3 is equal to the sum of VC and the voltage at the two ends of R3, i.e., the product of I1 multiplied by R3. In practical application, when the first output voltage is greater than the dc reference level, the voltage across the resistor is equal to the difference between the dc reference level and the first output voltage; when the second output voltage is greater than the DC reference level, the voltage across the resistor is equal to the difference between the DC reference level and the second output voltage.
The following specifically describes the principle of the LC filter with LC filter application circuit for reducing the overall power consumption of the audio amplifier according to the embodiment of the present application:
referring to fig. 5, a signal diagram of an audio amplifier operating in a full-wave modulation mode according to an embodiment of the present application is shown.
As shown in fig. 5, a signal diagram of an audio amplifier operating in a full-wave modulation mode according to an embodiment of the present application includes: half of the analog supply voltage HALFAVDD, VOP2, VON, and VOP. When VOP2 and VON2 are both less than VL, the voltage at the first input of integrator 200 is a fixed second common-mode reference voltage VC. At this time, the duty cycle of VON and VOP is equal to VC/2 × halfvdd. Since VC is greater than halfvdd, the duty cycles of VON and VOP are both less than 50% at this time.
Referring to fig. 6, a signal diagram of an audio amplifier operating in a single-side modulation mode according to an embodiment of the present application is shown.
As shown in fig. 6, a signal diagram of an audio amplifier operating in a single-side modulation mode according to an embodiment of the present application includes: half of the analog supply voltage HALFAVDD, VOP2, VON, and VOP. When VOP2 and VON2 are greater than VL, the voltage at the first input terminal of the integrator 200 is the first common-mode reference signal VCOM2. At this time, in order to completely output the information carried by VON2 and VOP2, when the first output voltage VON2 or the second output voltage VOP2 is greater than the dc reference level VL, VCOM2 is modulated so that the amplitude of the waveform of VON2 or VOP2 clamped in the lower half of VL, VOP2 or VON2 is greater than that before VCOM2 is modulated.
It should be noted that, in the audio amplifier, the average value of the first output voltage VON2 and the second output voltage VOP2 is the first common-mode reference voltage VCOM2 or the fixed second common-mode reference voltage VC. As shown in fig. 6, when VON2 is greater than VL, the embodiment of the present application may increase VCOM2 so that VON2 is clamped exactly at VL, and since VCOM2 is increased, VOP2 will be greater than VOP2 when VCOM2 is not modulated. At this time, the average of the duty ratios of VON and VOP is equal to VCOM2/2 × halfvdd. Since VCOM2 is typically larger than HALFAVDD, the average duty cycle of VON and VOP is typically less than 50% at this time.
Considering that voltage ripples may exist in VON2 and VOP2, in the embodiment of the present application, as a possible implementation manner, a difference between a maximum value of the triangular wave voltage and the dc reference level VL is determined by maximum voltage ripple amplitudes of the first output voltage VON2 and the second output voltage VOP2.
The external LC filter application circuit of the audio amplifier provided by the embodiment of the present application will be described as follows: referring to fig. 7, the circuit diagram of an LC filter application circuit provided in the embodiment of the present application is shown. As shown in fig. 7, the current I of the inductor in the LC filter application circuit provided in the embodiment of the present application ripple ：
Figure BDA0003058645910000101
Where D is the duty cycle of VON2 and VOP2, PVDD is the output supply voltage, f sw Is the output waveform frequency and L is the LC filter inductance value. It can be known that the current I on the inductor ripple The maximum value is proportional to the duty cycle, since the power consumption of the LC filter application circuit is proportional to the current I on the inductor ripple The duty cycles of VON2 and VOP2 are therefore positively correlated with the power consumption of the LC filter application circuit. Therefore, the method provided by the embodiment of the application can reduce the power consumption of the LC filter application circuit by reducing the duty ratio of VON2 and VOP2.
Referring to fig. 8, the graph is a line graph of an inductor current in an LC filter application circuit according to an embodiment of the present application. As shown in fig. 8, LC filtering in conventional full-wave modulationInductive current I in wave filter application circuit ripple The corresponding power consumption is larger than the inductive current I in the LC filter application circuit in the unilateral modulation provided by the embodiment of the application ripple Corresponding power consumption.
In the audio amplifier provided in the embodiment of the present application, as a possible implementation manner, the output stage circuit includes: a gate drive circuit and a power tube circuit. It is understood that the audio amplifier provided by the present application may have a low driving capability for the output signal of the audio amplifier, so that the device to which the audio amplifier is connected cannot be driven. Therefore, the audio amplifier provided by the application can improve the driving capability of the output signal through the output circuit and the driving circuit.
To sum up, when the voltage output by the integrator is smaller than the dc reference level, the audio amplifier provided in the embodiment of the present application makes the fixed second common mode reference voltage greater than half of the analog power voltage, so that the duty ratio of the square wave signal output by the audio amplifier is smaller than 50%. On the other hand, when the voltage output by the integrator is greater than the dc reference level, in order to completely output the input signal, the first common mode reference voltage is adjusted so that the voltage output by the integrator is less than or equal to the dc reference level, and then the duty ratio of the square wave signal output by the audio amplifier is fixed to be 50% smaller as a whole compared with the conventional full wave modulation, thereby further reducing the overall power consumption of the LC filter application circuit connected with the audio amplifier. Therefore, the duty ratio of the audio amplifier provided by the embodiment of the application is usually less than 50%, and the power consumption of the LC filter application circuit connected with the audio amplifier is in direct proportion to the duty ratio of the square wave signal output by the audio amplifier, so that the overall power consumption of the LC filter application circuit connected with the audio amplifier is reduced by the audio amplifier provided by the embodiment of the application.
According to the audio amplifier provided by the above embodiment, an embodiment of the present application further provides a sound apparatus, which is characterized by including the audio amplifier provided by the above embodiment, an LC filter application circuit and a speaker; the audio amplifier is connected with the first end of the LC filter application circuit, and the second end of the LC filter application circuit is connected with the loudspeaker.
According to the audio amplifier provided by the embodiment, the embodiment of the application also provides a water meter, which is characterized by comprising the audio amplifier, an LC filter application circuit and a loudspeaker, wherein the audio amplifier, the LC filter application circuit and the loudspeaker are provided by the embodiment; the audio amplifier is connected with the first end of the LC filter application circuit, and the second end of the LC filter application circuit is connected with the loudspeaker.
As can be seen from the above description of the embodiments, those skilled in the art can clearly understand that all or part of the steps in the above embodiment methods can be implemented by software plus a necessary general hardware platform. Based on such understanding, the technical solution of the present application may be essentially or partially implemented in the form of a software product, which may be stored in a storage medium, such as a ROM/RAM, a magnetic disk, an optical disk, etc., and includes several instructions for enabling a computer device (which may be a personal computer, a server, or a network communication device such as a media gateway, etc.) to execute the method according to the embodiments or some parts of the embodiments of the present application.
It should be noted that, in the present specification, each embodiment is described in a progressive manner, and each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments may be referred to each other. The method disclosed by the embodiment corresponds to the system disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the system part for description.
It should also be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising a … …" does not exclude the presence of another identical element in a process, method, article, or apparatus that comprises the element.
The foregoing description of the disclosed embodiments will enable those skilled in the art to make or use the invention in various modifications to these embodiments, which will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (11)

1. An audio amplifier, comprising: an integrator and a common mode reference voltage modulator;
the first input end and the second input end of the common mode reference voltage modulator are respectively connected with the first output end and the second output end of the integrator, and the output end of the common mode reference voltage modulator is connected with the first input end of the integrator;
the common mode reference voltage modulator is used for outputting a first common mode reference voltage to the first input end of the integrator according to the first output voltage and the second output voltage when at least one of the first output voltage of the first output end of the integrator and the second output voltage of the second output end of the integrator is larger than a direct current reference level, so that the first output voltage and the second output voltage are smaller than or equal to the direct current reference level.
2. The audio amplifier of claim 1, wherein the common mode reference voltage modulator is further configured to output a second fixed common mode reference voltage to the first input of the integrator when the first output voltage and the second output voltage are both less than the dc reference level; the fixed second common-mode reference voltage is greater than half of the analog supply voltage.
3. The audio amplifier of claim 2, wherein the common mode reference voltage modulator comprises:
a comparison circuit and a current-to-voltage circuit;
the comparison circuit is used for generating a first current according to the first output voltage and the second output voltage when the first output voltage is greater than a direct current reference level or the second output voltage is greater than the direct current reference level;
the current-to-voltage circuit is configured to output the first common-mode reference voltage to a first input terminal of the integrator according to the fixed second common-mode reference voltage and the first current.
4. The audio amplifier of claim 3, wherein the comparison circuit is specifically configured to positively correlate the magnitude of the first current with the difference between the dc reference level and the first output voltage when the first output voltage is greater than the dc reference level;
when the second output voltage is greater than the DC reference level, the magnitude of the first current is positively correlated to the difference between the DC reference level and the second output voltage.
5. The audio amplifier of claim 3 or 4, wherein the current to voltage conversion circuit comprises:
an operational amplifier and a resistor;
the positive input end of the operational amplifier is connected with the fixed second common-mode reference voltage; the negative input end of the operational amplifier is connected with the output end of the operational amplifier; the first end of the resistor is connected with the output end of the operational amplifier, and the second end of the resistor is connected with the first output current output by the output end of the comparison circuit and connected with the first input end of the integrator.
6. The audio amplifier of claim 5, wherein when the first output voltage is greater than the DC reference level, the voltage across the resistor is equal to the difference between the DC reference level and the first output voltage;
when the second output voltage is greater than the dc reference level, the voltage across the resistor is equal to the difference between the dc reference level and the second output voltage.
7. The audio amplifier of claim 1, wherein the pulse width modulation circuit comprises: the device comprises a first modulation comparator, a second modulation comparator and a triangular wave generating circuit;
the first modulation comparator is used for outputting a first modulation square wave according to the first output voltage and the triangular wave voltage generated by the triangular wave generating circuit;
the second modulation comparator is used for outputting a second modulation square wave according to the second output voltage and the triangular wave voltage generated by the triangular wave generating circuit;
the direct current reference level is greater than the maximum value of the triangular wave voltage.
8. The audio amplifier of claim 7, wherein the difference between the maximum value of the triangular wave voltage and the dc reference level is determined by the maximum voltage ripple amplitude of the first output voltage and the second output voltage.
9. The audio amplifier of claim 2, wherein an average of the first output voltage and the second output voltage is the first common mode reference voltage or the fixed second common mode reference voltage.
10. The audio amplifier of claim 1, wherein the output stage circuit comprises:
a gate drive circuit and a power tube circuit.
11. A sound box comprising an audio amplifier according to any one of claims 1 to 10, an LC filter application circuit and a loudspeaker;
the audio amplifier is connected with the first end of the LC filter application circuit, and the second end of the LC filter application circuit is connected with the loudspeaker.
CN202110506666.4A 2021-05-10 2021-05-10 Audio amplifier and related device Pending CN115333495A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110506666.4A CN115333495A (en) 2021-05-10 2021-05-10 Audio amplifier and related device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110506666.4A CN115333495A (en) 2021-05-10 2021-05-10 Audio amplifier and related device

Publications (1)

Publication Number Publication Date
CN115333495A true CN115333495A (en) 2022-11-11

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110506666.4A Pending CN115333495A (en) 2021-05-10 2021-05-10 Audio amplifier and related device

Country Status (1)

Country Link
CN (1) CN115333495A (en)

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