CN109861649B - Signal processing circuit and audio power amplifying circuit - Google Patents
Signal processing circuit and audio power amplifying circuit Download PDFInfo
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- CN109861649B CN109861649B CN201910132236.3A CN201910132236A CN109861649B CN 109861649 B CN109861649 B CN 109861649B CN 201910132236 A CN201910132236 A CN 201910132236A CN 109861649 B CN109861649 B CN 109861649B
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
- H03F1/30—Modifications of amplifiers to reduce influence of variations of temperature or supply voltage or other physical parameters
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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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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/68—Combinations of amplifiers, e.g. multi-channel amplifiers for stereophonics
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Abstract
The application provides a signal processing circuit and audio power amplifier circuit, include: the first amplifying unit is used for receiving a first input signal and a second input signal, amplifying the first input signal and the second input signal and outputting a first output signal and a second output signal; the adjusting unit is connected with the first amplifying unit and used for receiving the first output signal and the second output signal; when the first output signal is larger than or equal to the common-mode level signal, the adjusting unit outputs a first output signal and a second adjusting signal according to the first output signal and the second output signal; when the first output signal is smaller than the common-mode level signal, the adjusting unit outputs a first adjusting signal and a second output signal according to the first output signal and the second output signal; wherein the first adjustment signal is less than the first output signal; the second adjusting signal is smaller than the second output signal, and the conduction loss of the audio power amplifying circuit can be reduced by outputting different adjusting signals.
Description
Technical Field
The invention relates to the technical field of integrated circuits, in particular to a signal processing circuit and an audio power amplifying circuit.
Background
With the continuous development of integrated circuit technology, the integrated circuit technology is applied to portable electronic products more and more widely. In the application fields of mobile phones and the like, the volume and the tone quality can have important influence on user experience, and an audio power amplifier in an audio power amplifying circuit commonly used at present mainly obtains larger volume and better sound effect by outputting higher power. The AB-class audio power amplifier has the advantages of good linearity, simple design structure, few peripheral components, no EMI interference problem and pure tone quality, and is widely applied to audio power amplification circuits.
Although the class AB audio power amplifier has the above advantages, a series of problems are generated in the application process of obtaining a larger volume and a better sound effect by enabling the class AB audio power amplifier to output a higher power, wherein most importantly, when the audio power amplifier circuit of the class AB audio power amplifier is applied to output a higher power, the voltage drop of the power tube in the output stage circuit of the audio power amplifier circuit is larger, and the output voltage of the switching power supply providing the power supply voltage for the audio power amplifier is always constant, which results in an increase in the loss of the power tube in the output stage circuit of the audio power amplifier circuit, and further causes a very low efficiency of the audio power amplifier circuit, so that the heat productivity of the class AB audio power amplifier in the audio power amplifier circuit is greatly increased, and further causes an excessive heat productivity of a system using the class AB audio power amplifier, in severe cases, the power amplifier even starts over-temperature protection, which affects the normal operation of the electronic product.
Therefore, it is desirable to provide an audio power amplifier, which can improve the efficiency of the audio power amplifier to solve the problem of excessive heat generation of the system due to too low efficiency.
Disclosure of Invention
The invention provides a signal processing circuit and an audio power amplifying circuit, which improve the efficiency of an audio power amplifier in the audio power amplifying circuit and solve the problem of overlarge heat productivity of a system caused by low efficiency in the using process.
In order to achieve the above object, the embodiments of the present invention provide the following technical solutions:
a first aspect of the present invention discloses a signal processing circuit, including:
the first amplifying unit is used for receiving a first input signal and a second input signal, amplifying the first input signal and the second input signal and outputting a first output signal and a second output signal;
the adjusting unit is connected with the first amplifying unit and used for receiving the first output signal and the second output signal; when the first output signal is greater than or equal to a common mode level signal, the adjusting unit outputs the first output signal and a second adjusting signal according to the first output signal and the second output signal; when the first output signal is smaller than the common mode level signal, the adjusting unit outputs a first adjusting signal and a second output signal according to the first output signal and the second output signal;
wherein the first adjustment signal is less than the first output signal; the second adjustment signal is less than the second output signal.
Optionally, in the signal processing circuit, the adjusting unit includes:
the comparison unit is connected with the first amplification unit and used for receiving the first output signal, comparing the first output signal with the common-mode level signal, and outputting a first comparison signal when the first output signal is greater than or equal to the common-mode level signal; when the first output signal is smaller than the common mode level signal, the comparison unit outputs a second comparison signal;
the adjusting subunit is respectively connected with the first amplifying unit and the comparing unit and is used for receiving the first comparison signal, the second comparison signal, the first output signal and the second output signal, and the adjusting subunit outputs the first output signal and the second adjusting signal according to the first comparison signal, the first output signal and the second output signal; the adjusting subunit outputs a first adjusting signal and a second output signal according to the second comparison signal, the first output signal and the second output signal.
Optionally, in the signal processing circuit, the comparison unit includes:
a comparator, wherein a non-inverting input of the comparator is configured to receive the first output signal, an inverting input of the comparator is configured to receive the common mode level signal, and the comparator is configured to compare a magnitude between the first output signal and the common mode level signal;
when the first output signal is greater than or equal to the common mode level signal, the inverted output end of the comparator outputs a first comparison signal; and when the first output signal is smaller than the common mode level signal, the in-phase output end of the comparator outputs a second comparison signal.
Optionally, in the signal processing circuit, the adjusting subunit includes:
a first switch and a second switch; one end of the first switch is connected with one end of a first resistor, the other end of the first switch is connected with one end of the second switch, and the other end of the second switch is respectively connected with the other end of the first resistor and one end of a second resistor;
the on-off of the first switch is controlled by the first comparison signal, and the on-off of the second switch is controlled by the second comparison signal;
a common terminal of the first resistor and the first switch serves as a first input port of the adjusting subunit and is used for receiving the first output signal;
a common terminal of the first switch and the second switch is used as a first output port of the adjusting subunit to output the first output signal or the first adjusting signal;
a third switch and a fourth switch; one end of the third switch is connected with the other end of the second resistor and one end of the third resistor respectively, the other end of the third switch is connected with one end of the fourth switch, and the other end of the fourth switch is connected with the other end of the third switch;
the on-off of the third switch is controlled by the first comparison signal, and the on-off of the fourth switch is controlled by the second comparison signal;
a common terminal of the third resistor and the fourth switch serves as a second input port of the adjusting subunit, and is configured to receive the second output signal;
and a common terminal of the third switch and the fourth switch is used as a second output port of the adjusting subunit to output the second output signal or the second adjusting signal.
Optionally, in the signal processing circuit, the first amplifying unit includes:
an operational amplifier, wherein an inverting input terminal of the operational amplifier receives the first input signal through a fourth resistor, and a non-inverting output terminal of the operational amplifier outputs the first output signal, wherein a fifth resistor is connected between the inverting input terminal of the operational amplifier and the non-inverting output terminal of the operational amplifier;
the non-inverting input end of the operational amplifier receives the second input signal through a sixth resistor, and the inverting output end of the operational amplifier outputs the second output signal, wherein a seventh resistor is connected between the non-inverting input end of the operational amplifier and the inverting output end of the operational amplifier;
the operational amplifier is also for receiving the common-mode level and a supply voltage.
The second aspect of the present invention discloses an audio power amplifying circuit, comprising:
a second amplifying unit, and a signal processing circuit as described in any of the above; wherein:
the second amplifying unit is used for receiving the first output signal and the second adjusting signal output by the signal processing circuit, or receiving the second output signal and the first adjusting signal output by the signal processing circuit;
the second amplifying unit amplifies the first output signal and the second adjustment signal and outputs the amplified first output signal and the amplified second adjustment signal, or amplifies the second output signal and the first adjustment signal and outputs the amplified second output signal and the amplified first adjustment signal.
Optionally, in the audio power amplifying circuit, the second amplifying unit includes:
the power amplifier, the output stage circuit, the eighth resistor, the ninth resistor, the eleventh resistor and the tenth resistor;
wherein the inverting input terminal of the power amplifier receives the first output signal or the first adjustment signal through the eighth resistor; the non-inverting input end of the power amplifier receives the second output signal or a second adjusting signal through the ninth resistor;
the amplified second output signal or the amplified second adjustment signal output by the non-inverting output terminal of the power amplifier;
the amplified first output signal or the amplified first adjustment signal output by the inverting output terminal of the power amplifier;
the output stage circuit receives the second output signal amplified by the power amplifier or the second adjustment signal amplified by the power amplifier and the first output signal amplified by the power amplifier or the first adjustment signal amplified by the power amplifier, and outputs the second output signal amplified by the output stage circuit or the second adjustment signal amplified by the output stage circuit and the first output signal amplified by the output stage circuit or the first adjustment signal amplified by the output stage circuit;
the tenth resistor is connected between the inverting input end of the power amplifier and a port of the amplified second output signal or the amplified second adjustment signal output by the output stage circuit;
and the eleventh resistor is connected between the non-inverting input end of the power amplifier and a port of the amplified first output signal or the amplified first adjusting signal output by the output stage circuit.
Optionally, in the audio power amplifying circuit, the power amplifier is further configured to receive the common mode level signal.
Optionally, in the audio power amplifying circuit, the audio power amplifying circuit further includes:
the switching power supply unit is used for providing power supply voltage for the audio power amplification circuit;
wherein the switching power supply unit includes: the device comprises a reference generating unit and a basic switching power supply unit connected with the reference generating unit;
the reference generation unit generates a reference voltage corresponding to the sampling signal according to the sampling signal, and the basic switching power supply unit adjusts the power supply voltage according to the reference voltage.
According to the technical scheme, in the signal processing circuit and the audio power amplifying circuit, the first amplifying unit in the signal processing circuit is used for receiving the first input signal and the second input signal, amplifying the first input signal and the second input signal and outputting the first output signal and the second output signal; the adjusting unit is connected with the first amplifying unit and used for receiving the first output signal and the second output signal, and when the first output signal is larger than or equal to the common-mode level signal, the adjusting unit outputs the first output signal and the second adjusting signal according to the first output signal and the second output signal; when the first output signal is smaller than the common-mode level signal, the adjusting unit outputs a first adjusting signal and a second output signal according to the first output signal and the second output signal; wherein the first adjustment signal is less than the first output signal; the second adjusting signal is smaller than the second output signal, the first output signal and the second output signal can be adjusted according to the magnitude relation between the first output signal and the common mode level through the signal processing circuit, so that the conduction loss of a power tube in an output stage circuit of the audio power amplifying circuit can be reduced when the audio power amplifying circuit works, the problems that the power of the audio power amplifying circuit is too low due to unnecessary power waste, the calorific value of an AB type audio power amplifier in the audio power amplifying circuit is greatly increased, the calorific value of a system is too large and the like are solved, and the problem that the efficiency of the audio power amplifying circuit is low due to the fact that the voltage output by the switching power supply of the audio power amplifying circuit is constant is solved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
Fig. 1 is a circuit diagram of a conventional audio power amplifier circuit;
fig. 2 is a block diagram of a signal processing circuit according to an embodiment of the disclosure;
fig. 3 is a circuit diagram of a signal processing circuit according to an embodiment of the present disclosure;
fig. 4 is a structural diagram of an audio power amplifying circuit disclosed in an embodiment of the present application;
fig. 5 is a circuit diagram of an audio power amplifying circuit disclosed in an embodiment of the present application;
fig. 6 is a waveform diagram of a node of an audio power amplifying circuit according to an embodiment of the present disclosure.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Currently, an audio power amplifying circuit applied in an integrated circuit, as shown in fig. 1, includes: a first amplifying unit 101, configured to receive the first input signal INN and the second input signal INP, and amplify the first input signal INN and the second input signal INP to output a first output signal V1n and a second output signal V1 p; the second amplifying unit 102 is connected to the first amplifying unit 101, and is configured to receive the first output signal V1n and the second output signal V1p output by the first amplifying unit 101, amplify the first output signal V1n and the second output signal V1p, and output the amplified first output signal VON and the amplified second output signal VOP.
It should be noted that the second amplifying unit 102 includes a power amplifier AMPAB and an output stage circuit 103 connected to the power amplifier AMPAB, where the power amplifier AMPAB may be a class AB audio power amplifier, and the output stage circuit 103 includes a power tube. The first output signal V1n and the second output signal V1p output from the first amplifying unit 101 are received by the second amplifying unit 102 and amplified and output to make the audio power amplifying circuit operate. However, in the operation process of the audio power amplifying circuit, in order to make the audio power amplifying circuit obtain a larger volume and a better sound effect, the audio power amplifying circuit is usually implemented in a manner that the audio power amplifying circuit outputs a higher power.
In the application process of the audio power amplifying circuit outputting higher power to obtain higher volume and better sound effect, the voltage drop of a power tube in an output stage circuit in the audio power amplifying circuit is larger, the output voltage of a switching power supply providing power supply voltage for the audio power amplifier is always constant, the loss of the power tube of the output stage circuit in the audio power amplifying circuit is increased, and further the efficiency of the audio power amplifying circuit is very low, so that the calorific value of an AB type audio power amplifier in the audio power amplifying circuit is greatly increased, the calorific value of a system using the AB type audio power amplifier is overlarge, and even the power amplifier in the audio power amplifying circuit starts over-temperature protection to influence the normal work of an electronic product in severe cases.
In view of the above problems, an embodiment of the application provides a signal processing circuit and an audio power amplifying circuit, so as to solve the problem that the efficiency of the generated audio power amplifying circuit is too low and the heat value of a system is too large in the process that the audio power amplifying circuit obtains a larger volume and a better sound effect.
Referring to fig. 2, an embodiment of the present application provides a signal processing circuit, including:
the first amplifying unit 201 is configured to receive a first input signal and a second input signal, and the first amplifying unit 201 amplifies the first input signal and the second input signal and outputs a first output signal and a second output signal.
It should be noted that the first amplifying unit 201 may amplify the first input signal and the second output signal through an operational amplifier, or amplify the signal through another device having a function of amplifying the signal, where the amplification factor of the signal may be manually set or adjusted according to a user requirement, and the amplification factor is not limited or required.
An adjusting unit 202 connected to the first amplifying unit 201, for receiving the first output signal and the second output signal; when the first output signal is greater than or equal to the common mode level signal, the adjusting unit 202 outputs a first output signal and a second adjusting signal according to the first output signal and the second output signal; when the first output signal is smaller than the common mode level signal, the adjusting unit 202 outputs a first adjusting signal and a second output signal according to the first output signal and the second output signal.
Wherein the first adjustment signal is less than the first output signal; the second adjustment signal is less than the second output signal.
It should be further noted that the adjusting unit 202 may adjust the first output signal and the second output signal through a component having an adjusting signal size, so that the adjusted signals can meet the user requirement.
Through the first amplifying unit 201 and the adjusting unit 202, the first output signal and the second output signal can be adjusted according to the magnitude relation between the first output signal and the common mode level signal, so that the conduction loss of a power tube in an output stage circuit of the audio power amplifying circuit can be reduced when the audio power amplifying circuit works, the problems that the power of the audio power amplifying circuit is too low due to unnecessary power waste, the heat productivity of an AB class audio power amplifier in the audio power amplifying circuit is greatly increased, the heat productivity of a system is too large, and the problem that the efficiency of the audio power amplifying circuit is low due to the fact that the voltage output by a switching power supply is constant in the audio power amplifying circuit are solved.
Optionally, referring to fig. 3, in another embodiment of the present application, an implementation manner of the adjusting unit 302 includes:
a comparing unit 303 connected to the first amplifying unit 301, for receiving the first output signal V1n, comparing the first output signal V1n with the common mode level signal Vcm, and when the first output signal V1n is greater than or equal to the common mode level signal Vcm, the comparing unit 303 outputs a first comparison signal Q1; when the first output signal V1n is less than the common mode level signal Vcm, the comparing unit 303 outputs a second comparison signal Q2.
The comparing unit 303 may compare the received first output signal V1n with the common mode level signal Vcm through a comparator or other devices capable of comparing signals, and then output a comparison signal according to the comparison result. Of course, the comparator may compare the second output signal V1p with the common mode level signal Vcm in addition to the received first output signal V1n with the common mode level signal Vcm, and the specific implementation of the present embodiment is not affected by any comparison method.
Note that the common mode level signal Vcm mentioned in the comparing unit 303 is related to the common mode level signal in the first amplifying unit 301, and the numerical relationship thereof is an equivalent relationship. The common mode level signal Vcm at the first amplifying unit 301 is used to provide a bias voltage to the operational amplifier at the first amplifying unit 301, so that the operational amplifier is in an amplifying state, while the common mode level signal Vcm at the comparing unit 303 is only used as a comparison signal received by the comparator.
An adjusting subunit 304 connected to the first amplifying unit 301 and the comparing unit 303, respectively, and configured to receive the first comparison signal Q1, the second comparison signal Q2, the first output signal V1n, and the second output signal V1p, where the adjusting subunit 304 outputs a first output signal V1n and a second adjusting signal V2p according to the first comparison signal Q1, the first output signal V1n, and the second output signal V1 p; the adjusting subunit 304 outputs a first adjusting signal V2n and a second output signal V1p according to the second comparison signal Q2, the first output signal V1n and the second output signal V1 p.
In this embodiment, the comparison unit 303 connected to the first amplification unit 301 and the adjustment subunit 304 connected to the first amplification unit 301 and the comparison unit 303 are used to compare and adjust the first output signal V1n and the second output signal V1p output by the first amplification unit 301, so that the conduction loss of the power tube in the output stage circuit of the audio power amplification circuit is reduced, thereby avoiding the power of the audio power amplification circuit from being too low due to unnecessary power waste, and avoiding the heat generation of the class AB audio power amplifier in the audio power amplification circuit from being greatly increased, which results in the excessive heat generation of the system, and solving the problem of the low efficiency of the audio power amplification circuit due to the constant voltage output by the switching power supply.
Optionally, referring also to fig. 3, in another embodiment of the present application, an implementation of the comparing unit 303 includes:
a comparator COMP, wherein a non-inverting input terminal of the comparator COMP is configured to receive the first output signal V1n, an inverting input terminal of the comparator COMP is configured to receive the common mode level signal Vcm, and the comparator COMP is configured to compare a magnitude between the first output signal V1n and the common mode level signal Vcm.
When the first output signal V1n is greater than or equal to the common mode level signal Vcm, the inverting output terminal of the comparator COMP outputs a first comparison signal Q1; when the first input signal V1n is smaller than the common mode level signal Vcm, the non-inverting output terminal of the comparator COMP outputs a second comparison signal Q2.
In this embodiment, the comparing unit 303 compares the first output signal V1n with the common mode level signal Vcm and outputs a comparison signal by using a comparator, and controls the adjusting subunit 304 to adjust the first output signal V1n and the second output signal V1p, so as to achieve the purpose of adjusting and outputting the output signal.
In this embodiment, the function of the comparing unit 303 is realized by adopting an implementation manner of a comparator. The comparison unit 303 compares the first output signal and the second output signal output by the first amplification unit 301 according to the comparison result of the comparator, and then outputs the adjusted signal through the adjustment subunit 304, so that the conduction loss of a power tube in an output stage circuit of the audio power amplification circuit can be reduced when the audio power amplification circuit works, and therefore the problems that the power of the audio power amplification circuit is too low due to unnecessary power waste, the heat productivity of an AB-type audio power amplifier in the audio power amplification circuit is greatly increased, the heat productivity of a system is too high, and the problem that the efficiency of the audio power amplification circuit is low due to the constant voltage output by a switching power supply of the audio power amplification circuit is solved.
Optionally, referring also to fig. 3, in another embodiment of the present application, an implementation of the adjustment subunit 304 includes:
a first switch S1 and a second switch S2; one end of the first switch S1 is connected to one end of the first resistor R1, the other end of the first switch S1 is connected to one end of the second switch S2, and the other end of the second switch S2 is connected to the other end of the first resistor R1 and one end of the second resistor R2, respectively.
The on/off of the first switch S1 is controlled by a first comparison signal Q1, and the on/off of the second switch S2 is controlled by a second comparison signal Q2.
The common terminal of the first resistor R1 and the first switch S1 serves as a first input port of the adjusting subunit 304, for receiving the first input signal V1 n.
A common terminal of the first switch S1 and the second switch S2 serves as a first output port of the adjusting subunit 304, and outputs the first output signal V1n or the first adjusting signal V2 n.
A third switch S3 and a fourth switch S4; one end of the third switch S3 is connected to the other end of the second resistor R2 and one end of the third resistor R3, respectively, the other end of the third switch S3 is connected to one end of the fourth switch S4, and the other end of the fourth switch S4 is connected to the other end of the third switch S3.
The on/off of the third switch S3 is controlled by a first comparison signal Q1, and the on/off of the fourth switch S4 is controlled by a second comparison signal Q2.
The common terminal of the third resistor R3 and the fourth switch S4 serves as a second input port of the adjusting subunit 304, for receiving the second output signal V1 p.
A common terminal of the third switch S3 and the fourth switch S4 serves as a second output port of the adjusting subunit 304, and outputs the second output signal V1p or the second adjusting signal V2 p.
It should be noted that, when the first output signal V1n is greater than or equal to the common mode level signal Vcm, the comparing unit 303 outputs the first comparison signal Q1, and the first comparison signal Q1 controls on/off of the first switch S1 and the third switch S3, specifically, when the first output signal V1n is greater than or equal to the common mode level signal Vcm, the first switch S1 and the third switch S3 are controlled by the first comparison signal Q1 to be in a conducting state, and at this time, the signals output by the adjusting subunit 304 are the first output signal V1n and the second adjusting signal V2 p. When the first output signal V1n is smaller than the common mode level signal Vcm, the comparing unit 303 outputs a second comparison signal Q2, and the second comparison signal Q2 controls on/off of the second switch S2 and the fourth switch S4, specifically, when the first output signal V1n is smaller than the common mode level signal Vcm, the second switch S2 and the fourth switch S4 are controlled by the second comparison signal Q2 and are in a conducting state, and at this time, the signals output by the adjusting subunit 304 are the first adjusting signal V2n and the second output signal V1P.
It should be further noted that in the present embodiment, the first resistor R1 and the third resistor R3 are resistors with equal resistance, wherein the amplitude of the adjustment of the output signal by the adjustment subunit 304 is determined by the resistances of the first resistor R1, the second resistor R2, and the third resistor R3.
According to the connection relationship of the components in fig. 3, when the amplification factor of the operational amplifier in the first power amplification unit 301 is 2 and the common mode level signal Vcm is biased at Vdd/2, the following mathematical relationship can be obtained for the signal processing circuit:
V2n-Vocm=(V1n-Vcm)/2
V2p-Vocm=(V1p-Vcm)/2
it should be noted that Vocm represents a common mode level signal of the output of the operational amplifier, and its value is equal to the common mode level signal Vcm of the operational amplifier.
In this embodiment, the output signal is adjusted by controlling the on/off of the switch in the adjustment subunit, so that the adjusted output signal can reduce the conduction loss of the power tube in the output stage circuit of the audio power amplification circuit, thereby avoiding the power of the audio power amplification circuit from being too low due to unnecessary power waste, avoiding the over-high system heat productivity caused by the greatly increased heat productivity of the class AB audio power amplifier in the audio power amplification circuit, and solving the problem of low efficiency of the audio power amplification circuit due to the constant voltage output by the switching power supply.
Optionally, referring also to fig. 3, in another embodiment of the present application, an implementation of the first amplification unit 301, includes:
an operational amplifier AMP1, wherein an inverting input of the operational amplifier AMP1 receives the first input signal INN through a fourth resistor R4, and a non-inverting output of the operational amplifier AMP1 outputs a first output signal V1n, wherein a fifth resistor R5 is connected between the inverting input of the operational amplifier AMP1 and the non-inverting output of the operational amplifier AMP 1.
The non-inverting input terminal of the operational amplifier AMP1 receives the second input signal INP via the sixth resistor R6, and the inverting output terminal of the operational amplifier AMP1 outputs the second output signal V1p, wherein a seventh resistor R7 is connected between the non-inverting input terminal of the operational amplifier AMP1 and the inverting output terminal of the operational amplifier AMP 1.
The operational amplifier AMP1 is also operative to receive a common mode level signal Vcm and a power supply voltage Vbat. The common mode level signal Vcm is used to provide a bias voltage to the operational amplifier AMP1 to put it in an amplified state. The power supply voltage Vbat is the own power supply voltage of the operational amplifier AMP1 itself, and is mainly used for supplying the operational amplifier AMP1 to operate.
It should be noted that the resistances of the fourth resistor R4 and the fifth resistor R5 in the first amplifying unit 301 are equal in size and are resistors with the same type of parameters, which mainly play a role in stabilizing the input signal in the first amplifying unit 301, and prevent the input signal voltage received at the input terminal of the operational amplifier AMP1 from being too large, which may cause damage to components in the operational amplifier AMP 1. The sixth resistor R6 and the seventh resistor R7 are also resistors with equal resistance values and same type parameters, and are feedback resistors in the first amplifying unit 301, and the feedback resistors are used for determining the gain of the operational amplifier AMP1, so the gain of the above circuit is Av1= R5/R4= R7/R6.
Specific implementations of the present invention are described below with respect to a schematic diagram of the structure of an audio power amplification circuit.
Referring to fig. 4, an audio power amplifying circuit according to another embodiment of the present invention includes:
a second amplification unit 401, and the signal processing circuit 402 described above; wherein:
the second amplifying unit 401 is configured to receive the first output signal and the second adjustment signal output by the signal processing circuit 402, or receive the second output signal and the first adjustment signal output by the signal processing circuit 402;
the second amplification unit 401 amplifies the first output signal and the second adjustment signal and outputs the amplified first output signal and the amplified second adjustment signal, or amplifies the second output signal and the first adjustment signal and outputs the amplified second output signal and the amplified first adjustment signal.
As shown in fig. 5, in the audio power amplifying circuit disclosed in the embodiment of the present invention, the second amplifying unit 501 includes:
the power amplifier AMPAB, the output stage circuit 502, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, and an eleventh resistor R11.
Wherein, the inverting input terminal of the power amplifier AMPAB receives the first output signal V1n or the first adjusting signal V2n through the eighth resistor R8; the non-inverting input of the power amplifier AMPAB receives either said second output signal V1p or a second regulation signal V2p through said ninth resistor R9.
The amplified second output signal V1p or the amplified second adjustment signal V2p output by the non-inverting output of the power amplifier AMPAB.
The amplified first output signal V1n or the amplified first adjustment signal V2n output by the inverting output of the power amplifier AMPAB.
The output stage circuit 502 receives the second output signal V1p amplified by the power amplifier or the second adjustment signal V2p amplified by the power amplifier, and the first output signal V1n amplified by the power amplifier or the first adjustment signal V2n amplified by the power amplifier, and outputs the second output signal V1p amplified by the output stage circuit or the second adjustment signal V2p amplified by the output stage circuit, and the first output signal V1n amplified by the output stage circuit or the first adjustment signal V2n amplified by the output stage circuit.
The output stage circuit 502 receives the first output signal V1n amplified by the power amplifier or the first adjustment signal V2n amplified by the power amplifier, and the second output signal V1p amplified by the power amplifier or the second adjustment signal V2p amplified by the power amplifier, and then amplifies and outputs the received signals again.
For convenience of illustration and explanation, the output of the amplified second output signal V1p or the amplified second adjustment signal V2p is denoted by VON in the figure. The output of the amplified first output signal V1n or the amplified first adjustment signal V2n is indicated by VOP in the figure.
The amplified second output signal V1p or the amplified second adjustment signal V2p has a signal-inverted relationship with the first output signal V1n and the first adjustment signal V2n, i.e., VON has a signal-inverted relationship with the first output signal V1n and the first adjustment signal V2 n. The amplified first output signal V1n or the amplified first adjustment signal V2n has a signal-inverted relationship with the second output signal V1p and the second adjustment signal V2p, i.e., the VOP has a signal-inverted relationship with the second output signal V1p and the second adjustment signal V2 p.
A tenth resistor R10 is connected between the inverting input terminal of the power amplifier AMPAB and the port of the amplified second output signal V1p or the amplified second adjustment signal V2p output from the output stage circuit 502.
An eleventh resistor R11 is connected between the non-inverting input terminal of the power amplifier AMPAB and the port of the amplified first output signal V1n or the amplified first adjustment signal V2n output by the output stage circuit 502.
It should be noted that, in the second amplification unit 501, the power amplifier AMPAB receives the first output signal V1n or the first adjustment signal V2n through the eighth resistor R8, and receives the second adjustment signal V2p or the second output signal V1p through the ninth resistor R9, where the eighth resistor R8 and the ninth resistor R9 are resistors with equal resistance, and the main function of the second amplification unit 501 is to prevent the signal received by the power amplifier AMPAB from being too large and causing damage to the components in the power amplifier AMPAB. The tenth resistor R10 and the eleventh resistor R11 are also resistors with equal resistance values and same type parameters, and are feedback resistors in the second amplifying unit 501, and the feedback resistors are used for determining the gain of the power amplifier, so the gain of the above circuit is Av2= R10/R8= R11/R9.
It should be further noted that, in this embodiment, the power amplifier AMPAB may be a class AB power amplifier, or may be another type of power amplifier.
Optionally, referring to fig. 5 as well, in the audio power amplifying circuit disclosed in another embodiment of the present invention, the power amplifier is further configured to receive a common mode level signal Vcm.
It should be noted that the common mode level signal Vcm is used to provide a bias voltage to the power amplifier, so that the power amplifier is in an amplification state.
In this embodiment, the adjusted first output signal and the adjusted second output signal, or the adjusted first adjustment signal and the adjusted second output signal, are output by the received signal processing circuit, and are amplified by the second amplifying unit, so that the output amplified signal can reduce the conduction loss of a power tube in an output stage circuit of the audio power amplifying circuit when the audio power amplifying circuit is in operation, thereby avoiding that the power of the audio power amplifying circuit is too low due to unnecessary power waste, and the heat productivity of an AB class audio power amplifier in the audio power amplifying circuit is greatly increased, resulting in too large heat productivity of a system, and solving the problem of low efficiency of the audio power amplifying circuit due to the constant voltage output by the switching power supply.
Optionally, in the audio power amplifying circuit disclosed in another embodiment of the present invention, the audio power amplifying circuit further includes:
and the switching power supply unit is used for providing power supply voltage for the audio power amplification circuit.
Wherein, switching power supply unit includes: the device comprises a reference generating unit and a basic switching power supply unit connected with the reference generating unit.
The reference generating unit generates a reference voltage corresponding to the sampling signal according to the sampling signal, and the basic switching power supply unit adjusts the power supply voltage according to the reference voltage.
It should be noted that the switching power supply unit may be used to provide a supply voltage for a power amplifier and an output stage circuit in the audio power amplifying circuit. The switching power supply unit can generate power supply voltage which changes along with the change of the sampling signal in the reference generation unit according to the reference generation unit and the basic switching power supply unit, and the generated power supply voltage can reduce the conduction loss of a power tube in an output stage circuit of the audio power amplification circuit, so that the problem that the audio power amplification circuit is low in efficiency due to the fact that the voltage output by the switching power supply is constant is solved.
Referring to fig. 6, the present embodiment provides a waveform diagram of each node in fig. 4 and 5. From the figure, it can be seen that the signal output by the signal processing circuit 801 is related to the magnitude relationship between the first output signal V1n and the common mode level signal Vcm, and according to the magnitude relationship between the first output signal V1n and the common mode level signal Vcm, the on/off of the first switch, the second switch, the third switch and the fourth switch is controlled by the comparing unit, so that when the signal output by the signal processing circuit is greater than the common mode level signal, the positive signal is compressed and the negative signal is amplified, and when the signal passes through the second amplifying unit of the audio power amplifying circuit 802, the signal is inverted by the power amplifier, that is, the positive signal and the negative signal of the output signal after passing through the second amplifying unit are normally amplified and compressed.
In the signal processing circuit 801, the common mode level signal Vcm is used as a reference standard, the output signal higher than the common mode level Vcm is used as a positive-going signal, and the output signal lower than the common mode level Vcm is used as a negative-going signal, that is, the first output signal V1n and the second output signal V1p in the figure are negative-going signals, and the first adjusting signal V2n and the second adjusting signal V2p are positive-going signals.
At this time, the positive signal is normally amplified to enable the audio power amplifying circuit to normally work and output, and the compressed negative signal can reduce the conduction loss of an output stage power tube in the audio power amplifying circuit, namely the conduction loss of an NMOS power tube in the output stage circuit is optimized, so that unnecessary power waste is reduced, and the efficiency of the audio power amplifying circuit is improved.
Those skilled in the art can make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention 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.
It is further noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, 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 an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
Claims (9)
1. A signal processing circuit, comprising:
the first amplifying unit is used for receiving a first input signal and a second input signal, amplifying the first input signal and the second input signal and outputting a first output signal and a second output signal;
the adjusting unit is connected with the first amplifying unit and used for receiving the first output signal and the second output signal; when the first output signal is greater than or equal to a common mode level signal, the adjusting unit outputs the first output signal and a second adjusting signal according to the first output signal and the second output signal; when the first output signal is smaller than the common mode level signal, the adjusting unit outputs a first adjusting signal and a second output signal according to the first output signal and the second output signal;
wherein the first adjustment signal is less than the first output signal; the second adjustment signal is less than the second output signal.
2. The signal processing circuit of claim 1, wherein the adjustment unit comprises:
the comparison unit is connected with the first amplification unit and used for receiving the first output signal, comparing the first output signal with the common-mode level signal, and outputting a first comparison signal when the first output signal is greater than or equal to the common-mode level signal; when the first output signal is smaller than the common mode level signal, the comparison unit outputs a second comparison signal;
the adjusting subunit is respectively connected with the first amplifying unit and the comparing unit and is used for receiving the first comparison signal, the second comparison signal, the first output signal and the second output signal, and the adjusting subunit outputs the first output signal and the second adjusting signal according to the first comparison signal, the first output signal and the second output signal; the adjusting subunit outputs a first adjusting signal and a second output signal according to the second comparison signal, the first output signal and the second output signal.
3. The signal processing circuit of claim 2, wherein the comparison unit comprises:
a comparator, wherein a non-inverting input of the comparator is configured to receive the first output signal, an inverting input of the comparator is configured to receive the common mode level signal, and the comparator is configured to compare a magnitude between the first output signal and the common mode level signal;
when the first output signal is greater than or equal to the common mode level signal, the inverted output end of the comparator outputs a first comparison signal; and when the first output signal is smaller than the common mode level signal, the in-phase output end of the comparator outputs a second comparison signal.
4. The signal processing circuit of claim 2, wherein the adjustment subunit comprises:
a first switch and a second switch; one end of the first switch is connected with one end of a first resistor, the other end of the first switch is connected with one end of the second switch, and the other end of the second switch is respectively connected with the other end of the first resistor and one end of a second resistor;
the on-off of the first switch is controlled by the first comparison signal, and the on-off of the second switch is controlled by the second comparison signal;
a common terminal of the first resistor and the first switch serves as a first input port of the adjusting subunit and is used for receiving the first output signal;
a common terminal of the first switch and the second switch is used as a first output port of the adjusting subunit to output the first output signal or the first adjusting signal;
a third switch and a fourth switch; one end of the third switch is connected with the other end of the second resistor and one end of the third resistor respectively, the other end of the third switch is connected with one end of the fourth switch, and the other end of the fourth switch is connected with the other end of the third switch;
the on-off of the third switch is controlled by the first comparison signal, and the on-off of the fourth switch is controlled by the second comparison signal;
a common terminal of the third resistor and the fourth switch serves as a second input port of the adjusting subunit, and is configured to receive the second output signal;
and a common terminal of the third switch and the fourth switch is used as a second output port of the adjusting subunit to output the second output signal or the second adjusting signal.
5. The signal processing circuit of claim 1, wherein the first amplification unit comprises:
an operational amplifier, wherein an inverting input terminal of the operational amplifier receives the first input signal through a fourth resistor, and a non-inverting output terminal of the operational amplifier outputs the first output signal, wherein a fifth resistor is connected between the inverting input terminal of the operational amplifier and the non-inverting output terminal of the operational amplifier;
the non-inverting input end of the operational amplifier receives the second input signal through a sixth resistor, and the inverting output end of the operational amplifier outputs the second output signal, wherein a seventh resistor is connected between the non-inverting input end of the operational amplifier and the inverting output end of the operational amplifier;
the operational amplifier is also for receiving the common-mode level and a supply voltage.
6. An audio power amplification circuit, comprising:
a second amplification unit, and the signal processing circuit of any one of claims 1 to 5; wherein:
the second amplifying unit is used for receiving the first output signal and the second adjusting signal output by the signal processing circuit, or receiving the second output signal and the first adjusting signal output by the signal processing circuit;
the second amplifying unit amplifies the first output signal and the second adjustment signal and outputs the amplified first output signal and the amplified second adjustment signal, or amplifies the second output signal and the first adjustment signal and outputs the amplified second output signal and the amplified first adjustment signal.
7. The audio power amplification circuit of claim 6, wherein the second amplification unit comprises:
the power amplifier, the output stage circuit, the eighth resistor, the ninth resistor, the eleventh resistor and the tenth resistor;
wherein the inverting input terminal of the power amplifier receives the first output signal or the first adjustment signal through the eighth resistor; the non-inverting input end of the power amplifier receives the second output signal or a second adjusting signal through the ninth resistor;
the amplified second output signal or the amplified second adjustment signal output by the non-inverting output terminal of the power amplifier;
the amplified first output signal or the amplified first adjustment signal output by the inverting output terminal of the power amplifier;
the output stage circuit receives the second output signal amplified by the power amplifier or the second adjustment signal amplified by the power amplifier and the first output signal amplified by the power amplifier or the first adjustment signal amplified by the power amplifier, and outputs the second output signal amplified by the output stage circuit or the second adjustment signal amplified by the output stage circuit and the first output signal amplified by the output stage circuit or the first adjustment signal amplified by the output stage circuit;
the tenth resistor is connected between the inverting input end of the power amplifier and a port of the amplified second output signal or the amplified second adjustment signal output by the output stage circuit;
and the eleventh resistor is connected between the non-inverting input end of the power amplifier and a port of the amplified first output signal or the amplified first adjusting signal output by the output stage circuit.
8. The audio power amplification circuit of claim 7, wherein the power amplifier is further configured to receive the common mode level signal.
9. The audio power amplification circuit of claim 6, further comprising:
the switching power supply unit is used for providing power supply voltage for the audio power amplification circuit;
wherein the switching power supply unit includes: the device comprises a reference generating unit and a basic switching power supply unit connected with the reference generating unit;
the reference generation unit generates a reference voltage corresponding to the sampling signal according to the sampling signal, and the basic switching power supply unit adjusts the power supply voltage according to the reference voltage.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910132236.3A CN109861649B (en) | 2019-02-22 | 2019-02-22 | Signal processing circuit and audio power amplifying circuit |
| PCT/CN2020/075479 WO2020168993A1 (en) | 2019-02-22 | 2020-02-17 | Signal processing circuit and audio power amplifying circuit |
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| CN201910132236.3A CN109861649B (en) | 2019-02-22 | 2019-02-22 | Signal processing circuit and audio power amplifying circuit |
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| CN109861649B true CN109861649B (en) | 2020-12-11 |
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| CN109861649B (en) * | 2019-02-22 | 2020-12-11 | 上海艾为电子技术股份有限公司 | Signal processing circuit and audio power amplifying circuit |
| CN114137865B (en) * | 2021-11-01 | 2024-03-19 | 上海美控智慧建筑有限公司 | Output control circuit, controller and air conditioner |
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| US7365600B1 (en) * | 2005-06-02 | 2008-04-29 | Linear Technology Corporation | Non-feedback implemented control of the output-common mode of a differential amplifier |
| KR101155892B1 (en) * | 2006-09-11 | 2012-06-20 | 엘지전자 주식회사 | Audio unit of portable device and method of controlling the same |
| CN100588115C (en) * | 2006-09-18 | 2010-02-03 | 晶豪科技股份有限公司 | Half-wave impulse bandwidth modulation D audio amplifier |
| CN101465622B (en) * | 2007-12-18 | 2011-01-12 | 北京东微世纪科技有限公司 | D-genus audio power amplifier |
| US7973569B1 (en) * | 2010-03-17 | 2011-07-05 | Microchip Technology Incorporated | Offset calibration and precision hysteresis for a rail-rail comparator with large dynamic range |
| CN101931369B (en) * | 2010-08-02 | 2012-08-22 | 复旦大学 | Bridge output power supply voltage adaptive variable audio power amplifier |
| CN202334444U (en) * | 2011-10-31 | 2012-07-11 | 四川和芯微电子股份有限公司 | Adjustable-gain audio power amplifying circuit |
| CN104767498B (en) * | 2015-04-30 | 2017-07-21 | 上海艾为电子技术股份有限公司 | Gain control method and device |
| CN109861649B (en) * | 2019-02-22 | 2020-12-11 | 上海艾为电子技术股份有限公司 | Signal processing circuit and audio power amplifying circuit |
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