Digital-to-analog signal conversion circuit
A modular audio signal processing circuit using high-precision DA chips and strategic resistor-capacitor configurations addresses the issue of suboptimal audio quality in existing systems, achieving low distortion and noise with enhanced fidelity.
Patent Information
- Application Number
- CN202422111024.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-29
- Publication Date
- 2025-07-15
- Estimated Expiration
- 2034-08-29
AI Technical Summary
The existing digital-to-analog signal conversion circuits rely on the accuracy of the DA chip in signal processing capabilities, and lack comprehensive consideration of signal performance, resulting in poor quality of output sound signals.
The high-precision DA conversion chip CS4398 is adopted, and the peripheral circuit is built, including the AC voltage division conversion module and the linear partition module, and multiple signal processing is carried out to reduce noise and distortion through the cooperation of the DA conversion module, amplification matching module, filter module, op amp module, feedback adjustment module and protection module.
It realizes low distortion and low noise audio signal output, improves signal reduction and processing accuracy, and ensures circuit safety and signal quality.
Smart Images
Figure CN223109999U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of signal processing, in particular to a digital-to-analog signal conversion circuit. Background Art
[0002] When playing audio files such as music on a computer, a sound card is one of the essential components. The audio processing circuit of the sound card decodes the audio and outputs it to a power amplifier chip, and then plays the sound through a speaker.
[0003] The signal sent to the sound card in the computer is a digital signal, while the sound played by the speaker is an analog signal. Therefore, the performance of the digital-to-analog signal conversion circuit in the audio processing circuit determines the quality of the output sound signal. How to build a circuit to output an audio signal with low distortion and good sound quality to improve customer satisfaction is crucial.
[0004] The existing signal processing ability generally depends on the accuracy of the DA chip. The peripheral circuit is built according to the specifications of the chip, and it is rarely possible to consider building a signal processing circuit from aspects such as signal performance to assist in improving the signal quality. Summary of the Utility Model
[0005] To solve the problems in the prior art, the utility model provides a digital-to-analog signal conversion circuit.
[0006] The digital-to-analog signal conversion circuit of the utility model includes a DA conversion module, an amplification and matching module, a filtering module, an operational amplifier module, a feedback adjustment module, a protection module, and a signal output interface. Among them, the DA conversion module is used to convert a digital signal into an analog signal. The DA conversion module includes more than one set of first output terminals and second output terminals, and the first output terminal and the second output terminal cooperate to output a pair of differential signals. The first output terminal and the second output terminal are respectively connected to two input terminals of the amplification and matching module. The two output terminals of the amplification and matching module are respectively connected to the positive-phase input terminal and the negative-phase input terminal of the operational amplifier module through the filtering module. The output terminal of the operational amplifier module is respectively connected to the input terminal of the feedback adjustment module and the input terminal of the protection module. The output terminal of the feedback adjustment module is connected to one of the input terminals of the operational amplifier module. The output terminal of the protection module outputs the processed single-ended analog signal to the signal output interface.
[0007] Furthermore, it further includes an AC voltage division conversion module and a first DC blocking module, and the AC voltage division module and the first DC blocking module are arranged at the input terminal of the amplification and matching module.
[0008] Further, the AC voltage dividing and converting module includes more than one series-connected resistor. The first DC-blocking module uses a first-polarity capacitor. One end of the series-connected resistors is connected to the input end of the amplification and matching module, and the other end is connected to the positive electrode of the first-polarity capacitor. The negative electrode of the first-polarity capacitor is grounded.
[0009] Further, an adjustment module and a second DC-blocking module are further included. The adjustment module is arranged between the DA conversion module and the amplification and matching module, and the second DC-blocking module is arranged between the output end of the operational amplifier module and the input end of the protection module.
[0010] Further, the protection module includes an overcurrent protection unit, an interference suppression unit, and a filtering unit. Among them, the overcurrent protection unit is used to perform overcurrent protection on the circuit, the interference suppression unit is used to suppress high-frequency noise, spike interference, and electromagnetic interference on the signal line, and the filtering unit is used to perform filtering processing on the signal.
[0011] Further, the DA conversion module includes a DA chip U101 and peripheral devices. The DA chip U101 uses a CS4398 chip. Pins 3-6 of the DA chip U101 are connected to the main control for receiving signals from the main control. Pin 7 of the DA chip U101 is respectively connected to one end of a capacitor C114, the positive electrode of a polarized capacitor C113, and a 3.3V power supply. The other end of the capacitor C114 and the negative electrode of the polarized capacitor C113 are grounded. A parameter adjustment resistor is connected in series to each of pins 9-12 of the DA chip U101. The other ends of the parameter adjustment resistors of pins 9 and 12 are connected to the 3.3V power supply, and the other ends of the parameter adjustment resistors of pins 10-11 are grounded. Pin 13 is a reset pin and is connected between a series-connected resistor R113 and a capacitor C121. The other end of the resistor R113 is respectively connected to the 3.3V power supply and pin 14, and the other end of the capacitor C121 is grounded. Pin 15 is grounded through a parallel-connected capacitor C118 and a polarized capacitor C119. A capacitor C115 and a polarized capacitor C116 are connected in parallel between pin 16 and pin 17. Among them, pin 16 and pin 21 are grounded. Pin 17 and pin 22 are connected to the 5V power supply through a bead L111. In addition, pin 22 is also grounded through a parallel-connected capacitor C111 and a polarized capacitor C112. Pins 19 and 20 are the second differential signal output terminals, pins 23 and 24 are the second differential signal output terminals, pin 27 is connected to the 3.3V power supply and is connected to a grounded capacitor C106, and pin 26 is grounded through a polarized capacitor C109.
[0012] Further, the amplification and matching module includes a first resistor, a second resistor, a third resistor, and a fourth resistor. Among them, the first resistor and the second resistor are connected in series on the first differential signal line, the third resistor and the fourth resistor are connected in series on the second differential signal line, the filtering module includes two branches, the output end of the first branch is connected between the first resistor and the second resistor, and the output end of the second branch is connected between the third resistor and the fourth resistor.
[0013] Further, both the first branch and the second branch of the filtering module include one or more grounded capacitors connected in parallel.
[0014] Further, the feedback adjustment module includes a fifth resistor and a first capacitor. One end of the fifth resistor and the first capacitor is connected to the output end of the operational amplifier module, the other end of the fifth resistor is connected between the first resistor and the second resistor, and the first capacitor is connected to the output end of the second resistor.
[0015] Compared with the prior art, the beneficial effects of the present utility model are as follows:
[0016] Through the cooperation of each module after the DA conversion module of the present utility model, an audio signal with high indexes, low distortion, and low noise can be output.
[0017] By selecting a high-precision conversion chip and building parameter-setting resistors around the high-precision conversion chip, the reduction degree and processing precision of the signal can be set, meeting the reduction degree requirements of the present utility model, and the signal can be highly restored.
[0018] Through the amplification and matching module, the amplification multiple of the differential signal is accurately matched, and then it is sent to the operational amplifier module for processing to convert the differential signal into a single-ended signal. Before processing, through triple processing of the filtering module, the first DC blocking module, and the second DC blocking signal, the noise of the signal is effectively reduced. In addition, the differential signal is converted into an analog signal with a ratio of one to one, realizing a one-to-one restoration of the analog signal, with relatively low distortion rate and noise. In addition, through the protection module and filtering at the back end, the safety of the circuit and the quality of the output signal are improved.
[0019] The present utility model is built by simply selecting resistors, capacitors, etc. It has a simple and reliable structure, low cost, and good signal indexes. Description of the Drawings
[0020] In order to more clearly illustrate the solutions in the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.
[0021] Figure 1 Block diagram of the first embodiment of the present utility model;
[0022] Figure 2 Principle block diagram of the second embodiment of the present utility model;
[0023] Figure 3 Schematic diagram of the DA chip and its peripheral circuits;
[0024] Figure 4 Schematic diagram of a circuit of an amplification and matching module, a filtering module, an operational amplifier module, a feedback adjustment module, a protection module, and a signal output interface. Specific implementation manners
[0025] Unless otherwise defined, all technical and scientific terms used in the present utility model have the same meaning as commonly understood by those skilled in the technical field to which the present utility model belongs; the terms used in the description of the present utility model are only for the purpose of describing specific embodiments and are not intended to limit the present utility model; the terms "including" and "having" and any variations thereof in the description and claims of the present utility model and the above drawings are intended to cover non-exclusive inclusion. The terms "first", "second", etc. in the description and claims of the present utility model or the above drawings are used to distinguish different objects and not to describe a specific order.
[0026] Referring to "embodiment" in the present utility model means that the specific features, structures, or characteristics described in connection with the embodiment may be included in at least one embodiment of the present utility model. The phrase appearing at various positions in the description does not necessarily refer to the same embodiment, nor is it an exclusive, independent, or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described in the present utility model may be combined with other embodiments.
[0027] In order to enable those skilled in the art of the present technology to better understand the solution of the present utility model, the technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the drawings.
[0028] Such as Figure 1As shown in the figure, as an embodiment of the present utility model, the present utility model includes a DA conversion module, an amplification and matching module, a filtering module, an operational amplifier module, a feedback adjustment module, a protection module, and a signal output interface. Among them, the DA conversion module is used to convert digital signals into analog signals. The DA conversion module includes more than one group of first output terminals and second output terminals. The first output terminal and the second output terminal cooperate to output a pair of differential signals. The first output terminal and the second output terminal are respectively connected to two input terminals of the amplification and matching module. Two output terminals of the amplification and matching module are respectively connected to the non-inverting input terminal and the inverting input terminal of the operational amplifier module through the filtering module. The output terminal of the operational amplifier module is respectively connected to the input terminal of the feedback adjustment module and the input terminal of the protection module. The output terminal of the feedback adjustment module is connected to one of the input terminals of the operational amplifier module. The output terminal of the protection module outputs the processed single-ended analog signal to the signal output interface.
[0029] Through the cooperation of each module after the DA conversion module in this example, an audio signal with high indexes, low distortion, and low noise can be output. By selecting a high-precision conversion chip and building parameter-setting resistors around the high-precision conversion chip in the present utility model, the reduction degree and processing precision of the signal can be set, meeting the reduction degree requirements of the present utility model, and the signal can be highly restored.
[0030] Preferably, as another embodiment of the present utility model, this example further includes an AC voltage division conversion module and a first DC isolation module, and the AC voltage division module and the first DC isolation module are arranged at the input terminal of the amplification and matching module. Further, it also includes an adjustment module and a second DC isolation module. The adjustment module is arranged between the DA conversion module and the amplification and matching module, and the second DC isolation module is arranged between the output terminal of the operational amplifier module and the input terminal of the protection module.
[0031] The present utility model accurately matches the amplification factor of the differential signal through the amplification and matching module, and then conveys it to the operational amplifier module for processing to convert the differential signal into a single-ended signal. Before processing, through triple processing of the filtering module, the first DC isolation module, and the second DC isolation signal, the noise of the signal is effectively reduced. In addition, the differential signal is converted into an analog signal of one times, realizing a one-to-one restoration of the analog signal, with relatively low distortion rate and noise. In addition, through the protection module and filtering at the back end, the safety of the circuit and the quality of the output signal are improved.
[0032] Such as Figure 3As shown in the figure, the DA conversion module in this example includes a DA chip U101 and its peripheral devices. The DA chip U101 uses a CS4398 chip. Pins 3 - 6 of the DA chip U101 are connected to the main control for receiving signals from the main control. Pin 7 of the DA chip U101 is respectively connected to one end of a capacitor C114, the positive electrode of a polarized capacitor C113, and a 3.3V power supply. The other end of the capacitor C114 and the negative electrode of the polarized capacitor C113 are grounded. A parameter adjustment resistor is connected in series to each of pins 9 - 12 of the DA chip U101. The other ends of the parameter adjustment resistors of pins 9 and 12 are connected to the 3.3V power supply, and the other ends of the parameter adjustment resistors of pins 10 - 11 are grounded. Pin 13 is a reset pin and is connected between a series-connected resistor R113 and a capacitor C121. The other end of the resistor R113 is respectively connected to the 3.3V power supply and pin 14, and the other end of the capacitor C121 is grounded. Pin 15 is grounded through a parallel-connected capacitor C118 and a polarized capacitor C119. A capacitor C115 and a polarized capacitor C116 are connected in parallel between pin 16 and pin 17. Among them, pin 16 and pin 21 are grounded, pin 17 and pin 22 are connected to the 5V power supply through a bead L111. In addition, pin 22 is also grounded through a parallel-connected capacitor C111 and a polarized capacitor C112. Pins 19 and 20 are the second differential signal output terminals, pins 23 and 24 are the second differential signal output terminals, pin 27 is connected to the 3.3V power supply and is connected to a grounded capacitor C106, and pin 26 is grounded through a polarized capacitor C109.
[0033] In this example, a high-precision DA conversion chip is selected, which can provide clear audio conversion, achieve a 120 - decibel dynamic range and 0.0005% total harmonic distortion plus noise. In addition, the CS4398 chip supports 24 - bit conversion, and the sampling frequency can be as high as 192 kHz. In addition, in this example, by setting parameter setting resistors around the DA conversion chip and setting different resistors, different precisions and sampling rates, etc. can be adapted, so as to better adapt to the entire circuit of the present utility model.
[0034] As Figure 4 shown in the figure, the DA conversion chip in this example can output two groups of differential signals. Therefore, in this example, two signal processing branches are built to process the two groups of differential signals output by the DA conversion chip.
[0035] The structures of the first signal processing branch and the second signal processing branch are the same. In this example, one of the branches will be used to illustrate the present utility model in detail.
[0036] The adjustment module in this example includes two resistors R118 and R112 connected in series on the differential line for impedance matching of the signal input terminal. The resistance value is adjusted according to the actual situation.
[0037] The amplification matching module in this example includes a first resistor R119, a second resistor R120, a third resistor R123, and a fourth resistor R124. Among them, the first resistor R119 and the second resistor R120 are connected in series on the first differential signal line, and the third resistor R123 and the fourth resistor R124 are connected in series on the second differential signal line. It is used to set the amplification factor of the subsequent operational amplifier module. In this example, through operational amplifier processing, the differential signal is converted into an analog signal with a magnification of 1 times, so as to realize the equal-proportion restoration of the signal.
[0038] Similarly, the filtering module in this example includes two branches. The output end of the first branch is connected between the first resistor and the second resistor, and the output end of the second branch is connected between the third resistor and the fourth resistor. The filtering module in this example is filtering capacitors C117 and C128, and the circuit is simple and effective. Of course, this example can also be set as multiple parallel capacitors, or a Π-type filter and other structures.
[0039] The AC voltage division module in this example is set at the output end of the filtering module. The AC voltage division conversion module includes one or more series-connected resistors R127 and R128. The first DC blocking module uses a first-polarity capacitor C129. One end of the series-connected resistors R127 and R128 is connected to the input end of the amplification matching module, and the other end is connected to the positive electrode of the first-polarity capacitor C129. The negative electrode of the first-polarity capacitor C129 is grounded. Through the filtering module, AC voltage division, and then through the processing of the first DC blocking module, it can isolate the DC, convert the AC signal into a suitable signal intensity, send it into the operational amplifier module, reduce noise, and improve the signal accuracy at the input end of the operational amplifier module. In addition, in this example, a polarity capacitor C124 is also set at the output end of the operational amplifier module as the second DC blocking module to further isolate the DC signal of the signal.
[0040] The operational amplifier module in this example uses an operational amplifier U100. The operational amplifier U100 includes operational amplifiers U100A and U100B. The first signal processing branch and the second signal processing branch in this example share an operational amplifier. Among them, the first signal processing branch uses operational amplifier U100A, and the second signal processing branch uses operational amplifier U100B. The feedback adjustment module includes a fifth resistor R112 and a first capacitor C120. One end of the fifth resistor R112 and the first capacitor C120 is connected to the output end of the operational amplifier module U100B. The other end of the fifth resistor R112 is connected between the first resistor R119 and the second resistor R120, and the first capacitor C120 is connected to the output end of the second resistor R112. The first capacitor C120 in this example is used to adjust the phase of the operational amplifier U100B and suppress high-frequency oscillation. The second resistor R112 in this example serves as a feedback resistor and cooperates with the amplification matching resistor in the previous stage to enable the operational amplifier U100B to control the output of a reasonable amplification factor.
[0041] Such asFigure 4 As shown in the figure, the protection module in this example includes an overcurrent protection unit, an interference suppression unit, and a filtering unit. Among them, the overcurrent protection unit is used to protect the circuit against overcurrent, the interference suppression unit is used to suppress high-frequency noise, spike interference, and electromagnetic interference on the signal line, and the filtering unit is used to filter the signal. The overcurrent protection unit in this example can adopt devices such as resistors and switching tubes. The interference suppression unit in this example adopts a magnetic bead L102 and can also adopt devices such as electrostatic tubes. The filtering unit in this example adopts a filtering capacitor C105. After the output signal is processed by the protection module in this example, a highly restored analog signal is output to the output interface J101.
[0042] Compared with the prior art, the present utility model selects a high-precision processing chip and builds a signal processing circuit at the rear stage. Although simple resistors, capacitors, etc. are used for building, the structure is simple and reliable, the cost is low, and various indicators such as the noise, distortion degree, and signal-to-noise ratio of the signal are good, meeting the decoding requirements of various audio signals.
[0043] The above-described specific implementation manners are the preferred implementation manners of the present utility model, and do not limit the specific implementation scope of the present utility model thereby. The scope of the present utility model includes but is not limited to this specific implementation manner. All equivalent changes made in accordance with the present utility model are within the protection scope of the present utility model.
Claims
1. A digital-to-analog signal conversion circuit, characterized in that: It includes a DA conversion module, an amplification and matching module, a filtering module, an operational amplifier module, a feedback adjustment module, a protection module, and a signal output interface. Among them, the DA conversion module is used to convert digital signals into analog signals. The DA conversion module includes more than one set of first output terminals and second output terminals. The first output terminals and the second output terminals cooperate to output a pair of differential signals. The first output terminals and the second output terminals are respectively connected to the two input terminals of the amplification and matching module. The two output terminals of the amplification and matching module are respectively connected to the non-inverting input terminal and the inverting input terminal of the operational amplifier module through the filtering module. The output terminal of the operational amplifier module is respectively connected to the input terminal of the feedback adjustment module and the input terminal of the protection module. The output terminal of the feedback adjustment module is connected to one of the input terminals of the operational amplifier module. The output terminal of the protection module outputs the processed single-ended analog signal to the signal output interface.
2. The digital-to-analog signal conversion circuit according to claim 1, wherein: It further includes an AC voltage division and conversion module and a first DC isolation module, and the AC voltage division and conversion module and the first DC isolation module are arranged at the input terminal of the amplification and matching module.
3. The digital-to-analog signal conversion circuit according to claim 2, wherein: The AC voltage division and conversion module includes more than one series-connected resistor. The first DC isolation module uses a first-polarity capacitor. One end of the series-connected resistors is connected to the input terminal of the amplification and matching module, and the other end is connected to the positive electrode of the first-polarity capacitor. The negative electrode of the first-polarity capacitor is grounded.
4. The digital-to-analog signal conversion circuit according to claim 1, wherein: It further includes an adjustment module and a second DC isolation module. The adjustment module is arranged between the DA conversion module and the amplification and matching module. The second DC isolation module is arranged between the output terminal of the operational amplifier module and the input terminal of the protection module.
5. The digital-to-analog signal conversion circuit according to any one of claims 1-4, characterized in that: The protection module includes an overcurrent protection unit, an interference suppression unit, and a filtering unit. Among them, the overcurrent protection unit is used to perform overcurrent protection on the circuit. The interference suppression unit is used to suppress high-frequency noise, spike interference, and electromagnetic interference on the signal line. The filtering unit is used to perform filtering processing on the signal.
6. The digital-to-analog signal conversion circuit according to any one of claims 1-4, characterized in that: The DA conversion module includes a DA chip U101 and peripheral devices. The DA chip U101 uses a CS4398 chip. Pins 3-6 of the DA chip U101 are connected to the main control for receiving signals from the main control. Pin 7 of the DA chip U101 is connected to one end of a capacitor C114, the positive electrode of a polarized capacitor C113, and a 3.3V power supply. The other end of the capacitor C114 and the negative electrode of the polarized capacitor C113 are grounded. A parameter adjustment resistor is connected in series to each of pins 9-12 of the DA chip U101. The other ends of the parameter adjustment resistors of pins 9 and 12 are connected to the 3.3V power supply, and the other ends of the parameter adjustment resistors of pins 10-11 are grounded. Pin 13 is a reset pin and is connected between a series-connected resistor R113 and a capacitor C121. The other end of the resistor R113 is connected to the 3.3V power supply and pin 14 respectively, and the other end of the capacitor C121 is grounded. Pin 15 is grounded through a parallel-connected capacitor C118 and a polarized capacitor C119. A capacitor C115 and a polarized capacitor C116 are connected in parallel between pin 16 and pin 17. Among them, pin 16 and pin 21 are grounded, pin 17 and pin 22 are connected to the 5V power supply through a bead L111. In addition, pin 22 is also grounded through a parallel-connected capacitor C111 and a polarized capacitor C112. Pins 19 and 20 are the second differential signal output terminals, pins 23 and 24 are the second differential signal output terminals, pin 27 is connected to the 3.3V power supply and is connected to a grounded capacitor C106, and pin 26 is grounded through a polarized capacitor C109.
7. The digital-to-analog signal conversion circuit according to any one of claims 1-4, characterized in that: The amplification and matching module includes a first resistor, a second resistor, a third resistor, and a fourth resistor. Among them, the first resistor and the second resistor are connected in series on the first differential signal line, and the third resistor and the fourth resistor are connected in series on the second differential signal line. The filtering module includes two branches. The output terminal of the first branch is connected between the first resistor and the second resistor, and the output terminal of the second branch is connected between the third resistor and the fourth resistor.
8. The digital-to-analog signal conversion circuit according to claim 7, wherein: Both the first branch and the second branch of the filtering module include one or more parallel-connected grounded capacitors.
9. The digital-to-analog signal conversion circuit according to claim 7, wherein: The feedback adjustment module includes a fifth resistor and a first capacitor. One end of the fifth resistor and the first capacitor is connected to the output terminal of the operational amplifier module. The other end of the fifth resistor is connected between the first resistor and the second resistor, and the first capacitor is connected to the output terminal of the second resistor.