CN117713818A - Audio signal processing circuit and electronic equipment - Google Patents

Audio signal processing circuit and electronic equipment Download PDF

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Publication number
CN117713818A
CN117713818A CN202311645382.9A CN202311645382A CN117713818A CN 117713818 A CN117713818 A CN 117713818A CN 202311645382 A CN202311645382 A CN 202311645382A CN 117713818 A CN117713818 A CN 117713818A
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China
Prior art keywords
input end
transistor
differential input
differential
signal
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CN202311645382.9A
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Inventor
陈文韬
芦文
梁展荣
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Shenzhen Zhongke Lanxun Technology Co ltd
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Shenzhen Zhongke Lanxun Technology Co ltd
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Priority to CN202311645382.9A priority Critical patent/CN117713818A/en
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M1/00—Analogue/digital conversion; Digital/analogue conversion
    • H03M1/06—Continuously compensating for, or preventing, undesired influence of physical parameters
    • H03M1/0617—Continuously compensating for, or preventing, undesired influence of physical parameters characterised by the use of methods or means not specific to a particular type of detrimental influence
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M1/00—Analogue/digital conversion; Digital/analogue conversion
    • H03M1/12—Analogue/digital converters
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R3/00—Circuits for transducers, loudspeakers or microphones

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  • Engineering & Computer Science (AREA)
  • Theoretical Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Amplifiers (AREA)

Abstract

The application relates to the technical field of signal processing and discloses an audio signal processing circuit and electronic equipment. The audio signal processing circuit includes an analog-to-digital converter and a clamp circuit. The analog-to-digital conversion circuit is used for receiving the single-ended analog signal and converting the single-ended analog signal into a digital signal, and is provided with a differential input end for receiving the single-ended analog signal. The clamping circuit is electrically connected with the differential input end and is used for converting a single-ended analog signal at the differential input end into a current differential signal and clamping the differential input end to a target voltage. Through the arrangement, the current differential signal is generated and input into the analog-to-digital converter, the voltage of the differential input end is clamped at the target voltage, and the voltage swing of the differential input end is avoided, so that the signal distortion problem output by the analog-to-digital converter is improved, and the linearity of the analog-to-digital converter meets the application scene requirement.

Description

Audio signal processing circuit and electronic equipment
Technical Field
The disclosure relates to the technical field of signal processing, and in particular relates to an audio signal processing circuit and electronic equipment.
Background
In conventional microphone signal input circuits, the microphone signal is a single-ended analog signal. In order to convert the microphone signal into a differential signal and realize digital processing, a single-ended differential-to-differential circuit is generally used to convert the microphone signal into a voltage differential signal, and the voltage differential signal is input into an analog-to-digital converter to be converted into a digital signal for subsequent circuit processing and analysis.
However, the voltage at the virtual short point of the conventional single-ended to differential circuit swings, resulting in poor signal linearity and failure to meet the application requirements.
Disclosure of Invention
An object of an embodiment of the present disclosure is to provide an audio signal processing circuit and an electronic device, which aim to solve the problem that linearity of an analog-to-digital converter cannot meet requirements due to voltage swing.
In a first aspect, embodiments of the present application provide an audio signal processing circuit, including:
the analog-to-digital conversion circuit is used for receiving a single-ended analog signal and converting the single-ended analog signal into a digital signal, and is provided with a differential input end for receiving the single-ended analog signal; and
and the clamping circuit is electrically connected with the differential input end and used for converting the single-ended analog signal at the differential input end into a current differential signal and clamping the differential input end to a target voltage.
Optionally, the clamping circuit includes:
the error amplifying module is electrically connected with the differential input end and is used for acquiring a common-mode voltage of the differential input end and amplifying an error between the common-mode voltage and a preset reference voltage to acquire an error amplifying signal; and
the current differential signal generating module is respectively and electrically connected with the error amplifying module and the differential input end, and forms negative feedback with the error amplifying module, and is used for absorbing the single-ended analog signal of the differential input end, generating a current differential signal according to the error amplifying signal and outputting the current differential signal to the differential input end, and clamping the differential input end to the target voltage through the negative feedback.
Optionally, the error amplification module includes:
the resistor unit is electrically connected with the differential input end and is used for eliminating alternating current signal components of the differential input end and acquiring the common mode voltage of the differential input end; and
and the error amplifying unit is respectively and electrically connected with the resistor unit and the current differential signal generating module and is used for amplifying the error between the common mode voltage and the preset reference voltage so as to obtain an error amplifying signal.
Optionally, the resistance unit includes a first resistor and a second resistor with equal resistance values;
one end of the first resistor is connected with the positive end of the differential input end, and the other end of the first resistor is connected with the error amplifying unit;
one end of the second resistor is connected with the negative end of the differential input end, and the other end of the second resistor is connected with the error amplifying unit.
Optionally, the error amplifying unit includes a first operational amplifier, a positive phase input end of the first operational amplifier is used for accessing the preset reference voltage, a negative phase input end of the first operational amplifier is respectively connected with the other end of the first resistor and the other end of the second resistor, and an output end of the first operational amplifier is connected with the current differential signal generating module.
Optionally, the error amplification module includes:
the positive phase input end of the second operational amplifier is used for being connected with the preset reference voltage, the negative phase input end of the second operational amplifier is split into a first input end and a second input end, the first input end is connected with the positive end of the differential input end, and the second input end is connected with the negative end of the differential input end.
Optionally, the current differential signal generating module comprises a third resistor and a fourth resistor with equal resistance values;
one end of the third resistor is connected with the positive end of the differential input end, and the other end of the third resistor is connected with the error amplifying module;
one end of the fourth resistor is connected with the negative end of the differential input end, and the other end of the fourth resistor is connected with the error amplifying module.
Optionally, the current differential signal generating module includes a first transconductance stage and a second transconductance stage configured to output currents of the same magnitude;
the output end of the first transconductance stage is connected with the positive end of the differential input end, and the output end of the first transconductance stage is connected with the error amplifying module;
the output end of the second transconductance stage is connected with the positive end of the differential input end, and the output end of the second transconductance stage is connected with the error amplifying module.
Optionally, the second operational amplifier includes a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, a tail current source, a gain stage, and an output stage;
the grid electrode of the first transistor is used for being connected with the preset reference voltage, the drain electrode of the first transistor is connected with the positive electrode of the tail current source, and the source electrode of the first transistor is connected with the drain electrode of the fourth transistor;
the grid electrode of the second transistor is connected with the positive end of the differential input end, the source electrode of the second transistor is connected with the positive electrode of the tail current source, and the drain electrode of the second transistor is connected with the drain electrode of the fifth transistor;
the grid electrode of the third transistor is connected with the negative end of the differential input end, the source electrode of the third transistor is connected with the positive electrode of the tail current source, and the drain electrode of the third transistor is connected with the drain electrode of the fifth transistor;
the grid electrode of the fourth transistor is connected with the source electrode of the first transistor, and the source electrode of the fourth transistor is connected with the source electrode of the fifth transistor;
the grid electrode of the fifth transistor is connected with the grid electrode of the fourth transistor, and the drain electrode of the fifth transistor is connected with the input end of the gain stage;
the output end of the gain stage is connected with the output stage, and the output stage is connected with the current differential signal generation module;
the negative pole of tail current source ground.
In a second aspect, embodiments of the present application provide an electronic device comprising an audio signal processing circuit as described in any one of the above.
In the audio signal processing circuit provided in the embodiment of the application, the analog-to-digital conversion circuit is provided with a differential input end, and the differential input end is configured to receive a single-ended analog signal. The clamping circuit is connected with the differential input end, converts a single-ended analog signal of the differential input end into a current differential signal, and clamps the differential input end to a target voltage. The current differential signal enters an analog-to-digital conversion circuit, is converted by the analog-to-digital conversion current to obtain a digital signal, and is provided for a later-stage circuit.
Through the arrangement, the current differential signal is generated and input into the analog-to-digital converter, the voltage of the differential input end is clamped at the target voltage, and the voltage swing of the differential input end is avoided, so that the signal distortion problem output by the analog-to-digital converter is improved, and the linearity of the analog-to-digital converter meets the application scene requirement.
In addition, compared with the conversion of the single-ended analog signal into the voltage differential signal, the method has better anti-interference capability, is not influenced by the parameter changes of devices such as capacitance and inductance on the transmission path, and meanwhile, the problem of signal errors caused by the voltage division influence of functional devices and transmission line resistors on the transmission path is solved, so that the signal quality and accuracy of the single-ended analog signal are ensured.
Drawings
One or more embodiments are illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like references indicate similar elements, and in which the figures of the drawings are not to be taken in a limiting sense, unless otherwise indicated.
Fig. 1 is a first schematic block diagram of an audio signal processing circuit according to an embodiment of the present invention;
FIG. 2 is a second schematic block diagram of an audio signal processing circuit according to an embodiment of the present invention;
fig. 3 is a third schematic block diagram of an audio signal processing circuit according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of an audio signal processing circuit according to an embodiment of the present invention;
FIG. 5 is a schematic diagram of a microphone signal input circuit of the prior art;
FIG. 6 is a second schematic diagram of a clamp circuit according to an embodiment of the present invention;
FIG. 7 is a third principle diagram of the clamp circuit according to the embodiment of the present invention;
fig. 8 is a schematic diagram of a second operational amplifier according to an embodiment of the present invention.
Detailed Description
In order to facilitate an understanding of the present disclosure, the present disclosure is described in more detail below in conjunction with the accompanying drawings and specific examples. It will be understood that when an element is referred to as being "fixed" to another element, it can be directly on the other element or one or more intervening elements may be present therebetween. When an element is referred to as being "electrically connected" to another element, it can be directly connected to the other element or one or more intervening elements may be present therebetween. The terms "upper," "lower," "inner," "outer," "bottom," and the like as used in this specification refer to an orientation or positional relationship based on that shown in the drawings, merely to facilitate description of the disclosure and to simplify the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the disclosure. Furthermore, the terms "first," "second," "third," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terminology used in the description of the present disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The term "and/or" as used in this specification includes any and all combinations of one or more of the associated listed items. In addition, the technical features referred to in the different embodiments of the present disclosure described below may be combined with each other as long as they do not make a conflict with each other.
Referring to fig. 1 to 8, the present embodiment provides an audio signal processing circuit, in which a single-ended analog signal is one of signal types of audio signals, and an exemplary single-ended analog signal may be a microphone signal.
Referring to fig. 1 to 4, an audio signal processing circuit includes an analog-to-digital conversion circuit 10 and a clamping circuit 20. The analog-to-digital conversion circuit 10 is configured to receive a single-ended analog signal and convert the single-ended analog signal into a digital signal, and the analog-to-digital conversion circuit 10 is provided with a differential input terminal 11 configured to receive the single-ended analog signal. The clamping circuit 20 is electrically connected to the differential input terminal 11 for converting a single-ended analog signal at the differential input terminal 11 into a current differential signal and clamping the differential input terminal 11 to a target voltage.
Specifically, the differential input terminal 11 includes a positive terminal O1 of the differential input terminal 11 and a negative terminal O2 of the differential input terminal 11, and the positive terminal O1 of the differential input terminal 11 is configured to receive a single-ended analog signal. The analog-to-digital conversion circuit 10 includes a fully differential operational amplifier, a positive end O1 of the differential input end 11 is connected to a positive phase input end of the fully differential operational amplifier in the analog-to-digital conversion circuit 10, and a negative end O2 of the differential input end 11 is connected to a negative phase input end of the fully differential operational amplifier in the analog-to-digital conversion circuit 10.
The working principle of the audio signal processing circuit of this embodiment is as follows: the analog-to-digital conversion circuit 10 is provided with differential inputs 11, the differential inputs 11 being configured to receive single-ended analog signals. The clamp circuit 20 is connected to the differential input terminal 11, and converts a single-ended analog signal of the differential input terminal 11 into a current differential signal while clamping the differential input terminal 11 to a target voltage. The current differential signal enters the analog-to-digital conversion circuit 10, and is converted by the analog-to-digital conversion current to obtain a digital signal, and the digital signal is provided for a subsequent circuit.
It can be appreciated that in this embodiment, the clamping circuit 20 is used to convert the single-ended analog signal of the differential input terminal 11 into the current differential signal, and clamp the voltage of the differential input terminal 11 at the target voltage, so as to avoid the voltage swing of the differential input terminal 11, thereby improving the signal distortion problem output by the analog-to-digital converter, and enabling the linearity of the analog-to-digital converter to meet the application scenario requirement.
In addition, compared with the conversion of the single-ended analog signal into the voltage differential signal, the method has better anti-interference capability, is not influenced by the parameter changes of devices such as capacitance and inductance on the transmission path, and meanwhile, the problem of signal errors caused by the voltage division influence of functional devices and transmission line resistors on the transmission path is solved, so that the signal quality and accuracy of the single-ended analog signal are ensured.
Further, in the prior art, a single-ended analog signal is converted into a voltage differential signal, and a filter circuit, an isolation circuit and the like are added on a transmission path to eliminate noise or improve the anti-interference capability of the signal, but the cost of the functional circuit is increased. Therefore, the audio signal processing circuit of the present embodiment also has an advantage of low cost.
In some embodiments, referring to fig. 2, the clamping circuit 20 includes an error amplifying module 21 and a current differential signal generating module 22. The error amplification module 21 is electrically connected to the differential input terminal 11, and is configured to obtain a common-mode voltage of the differential input terminal 11, and amplify an error between the common-mode voltage and a preset reference voltage VCM, so as to obtain an error amplified signal. The current differential signal generating module 22 is electrically connected to the error amplifying module 21 and the differential input terminal 11, and forms negative feedback with the error amplifying module 21, and is configured to absorb a single-ended analog signal of the differential input terminal 11, generate a current differential signal according to the error amplifying signal, output the current differential signal to the differential input terminal 11, and clamp the differential input terminal 11 to a target voltage through the negative feedback.
It can be appreciated that the error amplification module 21 obtains a common-mode voltage of the differential input terminals 11, compares the common-mode voltage with a preset reference voltage VCM, and outputs an error amplification signal according to the comparison result. The current differential signal generating module 22 absorbs the single-ended analog signal of the differential input terminal 11 and generates a current differential signal according to the error amplified signal. In addition, the current differential signal generating module 22 forms negative feedback with the error amplifying module 21, and adjusts the common mode voltage of the differential input terminal 11 through the negative feedback so as to clamp the common mode voltage to the target voltage.
In some embodiments, referring to fig. 3, the error amplifying module 21 includes a resistor unit 211 and an error amplifying unit 212. The resistor unit 211 is electrically connected to the differential input terminal 11, and is configured to cancel the ac signal component of the differential input terminal 11 and obtain the common mode voltage of the differential input terminal 11. The error amplifying unit 212 is electrically connected to the resistor unit 211 and the current differential signal generating module 22, respectively, and is configured to amplify an error between the common mode voltage and the preset reference voltage VCM, so as to obtain an error amplified signal.
It will be appreciated that since the differential input terminal 11 has an aliasing of the ac signal and the common mode signal, the common mode voltage signal is obtained by providing the resistor unit 211 at the input terminal of the error amplifying unit 212 to cancel the ac signal component.
In some embodiments, referring to fig. 4, the resistor unit 211 includes a first resistor R1 and a second resistor R2 with equal resistance values. One end of the first resistor R1 is connected to the positive terminal O1 of the differential input terminal 11, and the other end of the first resistor R1 is connected to the error amplifying unit 212. One end of the second resistor R2 is connected to the negative terminal O2 of the differential input terminal 11, and the other end of the second resistor R2 is connected to the error amplifying unit 212.
Further, the error amplifying unit 212 includes a first operational amplifier U1, a positive phase input end of the first operational amplifier U1 is used for accessing a preset reference voltage VCM, a negative phase input end of the first operational amplifier U1 is respectively connected to the other end of the first resistor R1 and the other end of the second resistor R2, and an output end of the first operational amplifier U1 is connected to the current differential signal generating module 22.
It can be understood that the voltage of the positive terminal O1 and the voltage of the negative terminal O2 of the differential input terminal 11 are detected by using resistors in the present embodiment, and since the resistances of the first resistor R1 and the second resistor R2 are the same, the voltage of the common junction (point F) between the first resistor R1, the second resistor R2 and the negative terminal of the first operational amplifier U1 is also the common mode voltage. In this embodiment, the differential input terminal 11 is detected by using a resistor to obtain a common-mode voltage of the differential input terminal 11, and the common-mode voltage is provided to the first operational amplifier U1, so that the first operational amplifier U1 compares the common-mode voltage with the preset reference voltage VCM, and an error amplification signal is output. In addition, the output terminal of the first operational amplifier U1 returns to the negative phase input terminal through the current differential signal generating unit to form negative feedback, and the common mode voltage of the differential input terminal 11 is adjusted to the preset reference voltage VCM, thereby clamping the differential input terminal 11 to the target voltage.
In some embodiments, the current differential signal generation module 22 includes a third resistor R3 and a fourth resistor R4 that have equal resistance values. One end of the third resistor R3 is connected to the positive end O1 of the differential input terminal 11, and the other end of the third resistor R3 is connected to the error amplifying module 21. One end of the fourth resistor R4 is connected to the negative terminal O2 of the differential input terminal 11, and the other end of the fourth resistor R4 is connected to the error amplifying module 21.
Illustratively, the other end of the third resistor R3 is connected to the output terminal of the first comparator, and the other end of the fourth resistor R4 is connected to the output terminal of the first comparator.
It can be understood that the current differential signal generating module 22 converts the error amplified signal at the output end of the error amplifying module 21 into a current signal by adopting a resistor mode, and absorbs the single-ended analog signal through the converted current signal, so that the single-ended analog signal is converted into a current differential signal and is output to the analog-to-digital conversion circuit 10.
To further illustrate the technical solution of the present embodiment, a microphone signal input circuit used in the prior art is exemplified. Referring to fig. 5, in a microphone signal input circuit adopted in the prior art, the input circuit includes a single-ended to differential circuit electrically connected to an analog-to-digital conversion circuit 10, and the single-ended to differential circuit is provided with resistors Rm and Rn and a fully differential operational amplifier Um. The microphone signal is received by the single-ended differential circuit to obtain a voltage differential signal, the voltage differential signal enters the analog-to-digital conversion circuit 10, the transmission path of the microphone signal passes through resistors Rm and Rn and a fully differential operational amplifier Um, and the resistors Rm and Rn and the fully differential operational amplifier Um easily generate noise interference in the microphone signal transmission process, so that the quality of the microphone signal is affected.
It can be understood that, in the microphone signal input circuit of the prior art, the noise on the single-ended analog signal transmission path is generated by the resistors Rm and Rn, the fully differential operational amplifier Um and the analog-to-digital conversion circuit 10 in the single-ended differential circuit, while the noise on the single-ended analog signal transmission path of the embodiment is provided by the first resistor R1, the second resistor R2 and the analog-to-digital conversion circuit 10 in the clamp circuit 20, and the matching resistor at the negative phase input end of the first operational amplifier U1 provides common mode noise, which does not interfere with the current differential signal. Therefore, in the specific structure of the audio signal processing circuit of the embodiment, there are fewer devices that interfere with the transmission of the current differential signal, and compared with the prior art, the audio signal processing circuit has the advantage of low noise.
In addition, the single-ended to differential circuit in the prior art needs to meet the requirements of single-ended to differential and low noise, so that the size of the transistor used by the fully differential operational amplifier Um in the single-ended to differential circuit needs to be increased to reduce noise, but increasing the size of the transistor will result in increasing parasitic capacitance, which will affect the stability of the transistor, and in order to ensure stability, the driving current of the transistor will generally be increased, so that the power consumption of the transistor will be increased, and the power consumption of the whole circuit will also be increased correspondingly. The first operational amplifier U1 of the present embodiment generates common mode noise, and does not interfere with the generated current differential signal, so the audio signal processing circuit of the present embodiment has the advantage of low power consumption compared with the prior art.
In other embodiments, referring to fig. 6, the current differential signal generating unit may also have another circuit structure. Wherein the current differential signal generation module 22 comprises a first transconductance stage 221 and a second transconductance stage 222 configured to output currents of the same magnitude. The output end of the first transconductance stage 221 is connected to the positive end O1 of the differential input end 11, and the output end of the first transconductance stage 221 is connected to the error amplifying module 21. The output end of the second transconductance stage 222 is connected to the positive end O1 of the differential input end 11, and the output end of the second transconductance stage 222 is connected to the error amplifying module 21.
It can be understood that, the transconductance stage is adopted as a current output stage, and the error amplification signal output by the error amplification module 21 is converted into a current signal through the first transconductance stage 221 and the second transconductance stage 222, and the current signal absorbs the single-ended analog signal, so that the single-ended analog signal is converted into a current differential signal and is output to the analog-to-digital conversion circuit 10.
In another embodiment, referring to fig. 7, the error amplifying module 21 may have another circuit structure. The error amplifying module 21 includes a second operational amplifier U2, a positive phase input end of the second operational amplifier U2 is used for accessing a preset reference voltage VCM, a negative phase input end of the second operational amplifier U2 is of a differential input structure, the negative phase input end of the second operational amplifier U2 includes a first input end P1 and a second input end P2, the first input end P1 is connected with a positive end O1 of the differential input end 11, and the second input end P2 is connected with a negative end O2 of the differential input end 11.
It can be understood that the negative phase input end of the second operational amplifier U2 adopts a differential input structure, including a first input end P1 and a second input end P2, the positive end O1 voltage and the negative end O2 voltage of the differential input end 11 are respectively obtained through the first input end P1 and the second input end P2, the common mode voltage of the differential input end 11 is obtained according to the positive end O1 voltage and the negative end O2 voltage, and then the common mode voltage is compared with the preset reference voltage VCM, so as to output an error amplification signal. In addition, the output terminal of the second operational amplifier U2 returns to the negative phase input terminal through the current differential signal generating unit to form negative feedback, and the common mode voltage of the differential input terminal 11 is adjusted to the preset reference voltage VCM, thereby clamping the differential input terminal 11 to the target voltage.
Optionally, referring to fig. 8, the specific structure of the second operational amplifier U2 is provided in this embodiment, and further described. The second operational amplifier U2 includes a first transistor Q1, a second transistor Q2, a third transistor Q3, a fourth transistor Q4, a fifth transistor Q5, a tail current source I1, a gain stage 213, and an output stage (not shown in the drawing). The gate of the first transistor Q1 is used for accessing a preset reference voltage VCM, the drain of the first transistor Q1 is connected to the positive electrode of the tail current source I1, and the source of the first transistor Q1 is connected to the drain of the fourth transistor Q4.
The gate of the second transistor Q2 is connected to the positive terminal O1 of the differential input terminal 11, the source of the second transistor Q2 is connected to the positive terminal of the tail current source I1, and the drain of the second transistor Q2 is connected to the drain of the fifth transistor Q5. The gate of the third transistor Q3 is connected to the negative terminal O2 of the differential input terminal 11, the source of the third transistor Q3 is connected to the positive terminal of the tail current source I1, and the drain of the third transistor Q3 is connected to the drain of the fifth transistor Q5. The gate of the fourth transistor Q4 is connected to the source of the first transistor Q1, and the source of the fourth transistor Q4 is connected to the source of the fifth transistor Q5.
The gate of the fifth transistor Q5 is connected to the gate of the fourth transistor Q4, and the drain of the fifth transistor Q5 is connected to the input of the gain stage 213. The output terminal of the gain stage 213 is connected to an output stage, which is connected to the current differential signal generating module 22. The negative pole of tail current source I1 is grounded.
It can be understood that the gate of the first transistor Q1 is the positive input terminal of the second operational amplifier U2, the gate of the second transistor Q2 is the first input terminal of the negative phase of the second operational amplifier U2, and the gate of the third transistor Q3 is the second input terminal of the second operational amplifier U2. The fourth transistor Q4 and the fifth transistor Q5 form a current mirror. The input end of the gain stage 213 obtains the voltages of the common junction of the drain electrode of the second transistor Q2, the drain electrode of the third transistor Q3 and the drain electrode of the fifth transistor Q5, and outputs an error amplified signal from the output stage after gain amplification. The dimensions of the second transistor Q2 and the third transistor Q3 are half the dimensions of the first transistor Q1.
In the second operational amplifier U2 of the present embodiment, compared with the first operational amplifier U1, the negative phase input terminal adopts the differential pair transistor composed of the second transistor Q2 and the third transistor Q3, and the common mode voltage of the differential input terminal 11 is obtained through this structure. In the working process of the second operational amplifier U2, if the common-mode voltage of the differential pair tube is lower than the preset reference voltage VCM, the voltage at the point E becomes high, the output of the gain stage 213 becomes high, and the positive terminal O1 and the negative terminal O2 of the differential input terminal 11 are pulled high under the action of negative feedback until the common-mode voltage is clamped at the preset reference voltage VCM. The voltage swing amplitude of the differential input terminal 11 of the present embodiment is limited by the input to the tube saturation voltage of the second operational amplifier U2, so that the present embodiment is suitable for application scenarios where the voltage swing of the differential input terminal 11 is small.
The embodiment also provides an electronic device, which comprises the audio signal processing circuit. The electronic device may be, for example, a microphone audio device or the like.
Finally, it should be noted that: the above embodiments are merely for illustrating the technical solution of the present disclosure, and are not limiting thereof; the technical features of the above embodiments or in different embodiments may also be combined under the idea of the present disclosure, the steps may be implemented in any order, and there are many other variations of the different aspects of the present disclosure as described above, which are not provided in details for the sake of brevity; although the present disclosure has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present disclosure.

Claims (10)

1. An audio signal processing circuit, comprising:
the analog-to-digital conversion circuit is used for receiving a single-ended analog signal and converting the single-ended analog signal into a digital signal, and is provided with a differential input end for receiving the single-ended analog signal; and
and the clamping circuit is electrically connected with the differential input end and used for converting the single-ended analog signal at the differential input end into a current differential signal and clamping the differential input end to a target voltage.
2. The audio signal processing circuit of claim 1, wherein the clamping circuit comprises:
the error amplifying module is electrically connected with the differential input end and is used for acquiring a common-mode voltage of the differential input end and amplifying an error between the common-mode voltage and a preset reference voltage to acquire an error amplifying signal; and
the current differential signal generating module is respectively and electrically connected with the error amplifying module and the differential input end, and forms negative feedback with the error amplifying module, and is used for absorbing the single-ended analog signal of the differential input end, generating a current differential signal according to the error amplifying signal and outputting the current differential signal to the differential input end, and clamping the differential input end to the target voltage through the negative feedback.
3. The audio signal processing circuit of claim 2, wherein the error amplification module comprises:
the resistor unit is electrically connected with the differential input end and is used for eliminating alternating current signal components of the differential input end and acquiring the common mode voltage of the differential input end; and
and the error amplifying unit is respectively and electrically connected with the resistor unit and the current differential signal generating module and is used for amplifying the error between the common mode voltage and the preset reference voltage so as to obtain an error amplifying signal.
4. The audio signal processing circuit according to claim 3, wherein the resistance unit includes a first resistance and a second resistance having equal resistance values;
one end of the first resistor is connected with the positive end of the differential input end, and the other end of the first resistor is connected with the error amplifying unit;
one end of the second resistor is connected with the negative end of the differential input end, and the other end of the second resistor is connected with the error amplifying unit.
5. The audio signal processing circuit according to claim 4, wherein the error amplifying unit includes a first operational amplifier, a positive phase input terminal of the first operational amplifier is used for accessing the preset reference voltage, a negative phase input terminal of the first operational amplifier is respectively connected to the other end of the first resistor and the other end of the second resistor, and an output terminal of the first operational amplifier is connected to the current differential signal generating module.
6. The audio signal processing circuit of claim 2, wherein the error amplification module comprises:
the positive phase input end of the second operational amplifier is used for being connected with the preset reference voltage, the negative phase input end of the second operational amplifier is split into a first input end and a second input end, the first input end is connected with the positive end of the differential input end, and the second input end is connected with the negative end of the differential input end.
7. The audio signal processing circuit according to claim 2, wherein the current differential signal generating module includes a third resistor and a fourth resistor having equal resistance values;
one end of the third resistor is connected with the positive end of the differential input end, and the other end of the third resistor is connected with the error amplifying module;
one end of the fourth resistor is connected with the negative end of the differential input end, and the other end of the fourth resistor is connected with the error amplifying module.
8. The audio signal processing circuit of claim 2, wherein the current differential signal generation module comprises a first transconductance stage and a second transconductance stage configured to output currents of equal magnitude;
the output end of the first transconductance stage is connected with the positive end of the differential input end, and the output end of the first transconductance stage is connected with the error amplifying module;
the output end of the second transconductance stage is connected with the positive end of the differential input end, and the output end of the second transconductance stage is connected with the error amplifying module.
9. The audio signal processing circuit of claim 6, wherein the second operational amplifier comprises a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, a tail current source, a gain stage, and an output stage;
the grid electrode of the first transistor is used for being connected with the preset reference voltage, the drain electrode of the first transistor is connected with the positive electrode of the tail current source, and the source electrode of the first transistor is connected with the drain electrode of the fourth transistor;
the grid electrode of the second transistor is connected with the positive end of the differential input end, the source electrode of the second transistor is connected with the positive electrode of the tail current source, and the drain electrode of the second transistor is connected with the drain electrode of the fifth transistor;
the grid electrode of the third transistor is connected with the negative end of the differential input end, the source electrode of the third transistor is connected with the positive electrode of the tail current source, and the drain electrode of the third transistor is connected with the drain electrode of the fifth transistor;
the grid electrode of the fourth transistor is connected with the source electrode of the first transistor, and the source electrode of the fourth transistor is connected with the source electrode of the fifth transistor;
the grid electrode of the fifth transistor is connected with the grid electrode of the fourth transistor, and the drain electrode of the fifth transistor is connected with the input end of the gain stage;
the output end of the gain stage is connected with the output stage, and the output stage is connected with the current differential signal generation module;
the negative pole of tail current source ground.
10. An electronic device comprising an audio signal processing circuit as claimed in any one of claims 1-9.
CN202311645382.9A 2023-12-01 2023-12-01 Audio signal processing circuit and electronic equipment Pending CN117713818A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202311645382.9A CN117713818A (en) 2023-12-01 2023-12-01 Audio signal processing circuit and electronic equipment

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202311645382.9A CN117713818A (en) 2023-12-01 2023-12-01 Audio signal processing circuit and electronic equipment

Publications (1)

Publication Number Publication Date
CN117713818A true CN117713818A (en) 2024-03-15

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
CN202311645382.9A Pending CN117713818A (en) 2023-12-01 2023-12-01 Audio signal processing circuit and electronic equipment

Country Status (1)

Country Link
CN (1) CN117713818A (en)

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