An audio low frequency signal gain control circuit and related apparatus

Abstract

The embodiment of the application provides an audio low-frequency signal gain control circuit and a related device, which comprise an input processing sub-circuit, a non-dynamic low-frequency signal processing sub-circuit, a dynamic low-frequency signal processing sub-circuit, a signal synthesis sub-circuit, an adaptive gain control sub-circuit and a bass speaker. The input processing sub-circuit is used for pre-processing an input stereo audio signal to obtain a first audio low-frequency signal; the non-dynamic low-frequency signal processing sub-circuit is used for processing the first audio low-frequency signal to obtain a non-dynamic audio low-frequency signal; the dynamic low-frequency signal processing sub-circuit is used for separating a dynamic audio low-frequency signal; the signal synthesis sub-circuit is used for merging the non-dynamic audio low-frequency signal and the dynamic audio low-frequency signal to obtain an audio low-frequency signal; the adaptive gain control sub-circuit is used for gain control on the audio low-frequency signal; and the bass speaker is used for outputting the audio low-frequency signal. In this way, the adaptive gain on the audio low-frequency signal is realized through an analog circuit.

Description

Technical Field

[0001] This application belongs to the field of audio signal processing technology, specifically relating to an audio low-frequency signal gain control circuit and related devices. Background Technology

[0002] Currently, existing technologies achieve adaptive dynamic gain control of low-frequency audio signals through digital circuits (DSP chips). However, chip-level (DSP) technology is costly and requires the writing of corresponding programs, which complicates the simple processing of low-frequency audio signals. Summary of the Invention

[0003] This application provides an audio low-frequency signal gain control circuit and related device, aiming to achieve adaptive gain of audio low-frequency signals through analog circuits.

[0004] In a first aspect, embodiments of this application provide an audio low-frequency signal gain control circuit, applied to an electronic device, comprising:

[0005] The input processing sub-circuit is used to preprocess the input stereo audio signal to obtain the first low-frequency audio signal;

[0006] A non-dynamic low-frequency signal processing sub-circuit, connected to the input processing sub-circuit, is used to process the first audio low-frequency signal to obtain a non-dynamic audio low-frequency signal.

[0007] A dynamic low-frequency signal processing sub-circuit, connected to the input processing sub-circuit, is used to separate the dynamic audio low-frequency signal;

[0008] A signal synthesis sub-circuit, connected to the non-dynamic low-frequency signal processing sub-circuit and the dynamic low-frequency signal processing sub-circuit, is used to combine the non-dynamic audio low-frequency signal and the dynamic audio low-frequency signal to obtain an audio low-frequency signal;

[0009] An adaptive gain control sub-circuit, connected to the dynamic low-frequency signal processing sub-circuit, is used to perform adaptive gain control on the audio low-frequency signal and adjust the audio low-frequency signal.

[0010] A subwoofer, connected to the signal synthesis sub-circuit, is used to output the low-frequency audio signal.

[0011] Secondly, embodiments of this application provide an audio low-frequency signal gain control device, characterized in that it is applied to an electronic device and includes the audio low-frequency signal gain control circuit as described in the first aspect.

[0012] Thirdly, embodiments of this application provide an audio device, characterized in that it includes an audio low-frequency signal gain control circuit as described in the first aspect.

[0013] Fourthly, embodiments of this application provide an electronic device, characterized in that it includes an audio low-frequency signal gain control circuit as described in the first aspect.

[0014] As can be seen, in this embodiment, the input stereo audio signal is first preprocessed by the input processing sub-circuit to obtain a first low-frequency audio signal; secondly, the first low-frequency audio signal is processed by the non-dynamic low-frequency signal processing sub-circuit to obtain a non-dynamic low-frequency audio signal; then, the dynamic low-frequency audio signal is separated from the first low-frequency audio signal by the dynamic low-frequency signal processing sub-circuit; finally, the non-dynamic low-frequency audio signal and the dynamic low-frequency audio signal are combined by the signal synthesis sub-circuit to obtain the low-frequency audio signal; the adaptive gain control sub-circuit controls the gain of the low-frequency audio signal; and the woofer outputs the low-frequency audio signal. Thus, adaptive gain of the low-frequency audio signal is achieved through analog circuitry. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the structure of an audio low-frequency signal gain control circuit provided in an embodiment of this application;

[0017] Figure 2 This is a schematic diagram of the specific structure of an audio low-frequency signal gain control circuit provided in an embodiment of this application;

[0018] Figure 3 This is a schematic diagram of the adaptive gain control value circuit in an audio low-frequency signal gain control circuit provided in this application embodiment;

[0019] Figure 4 This is a circuit diagram of an input processing sub-circuit, a portion of a non-dynamic low-frequency signal processing sub-circuit, and a portion of a dynamic low-frequency signal processing sub-circuit in an audio low-frequency signal gain control circuit provided in this application embodiment;

[0020] Figure 5 This is a circuit diagram of another part of the non-dynamic low-frequency signal processing sub-circuit, another part of the dynamic low-frequency signal processing sub-circuit, and the signal synthesis sub-circuit in an audio low-frequency signal gain control circuit provided in this application embodiment;

[0021] Figure 6This is a circuit diagram of an adaptive gain control sub-circuit for an audio low-frequency signal gain control circuit provided in an embodiment of this application. Detailed Implementation

[0022] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0023] The terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, systems, products, or apparatuses.

[0024] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0025] The following is a brief introduction to the relevant terminology used in this application.

[0026] Non-dynamic low-frequency audio signal: a general audio signal, which in this application refers to a signal that does not participate in adaptive gain control.

[0027] Dynamic low-frequency audio signal: An audio signal connected to an adaptive gain control circuit that has automatic gain compensation or attenuation. In this application, it refers to a signal that participates in adaptive gain control to adjust the low-frequency audio signal.

[0028] Currently, existing technologies achieve adaptive dynamic gain control of low-frequency audio signals through digital circuits (DSP chips). However, chip-level (DSP) technology is costly and requires the writing of corresponding programs, which complicates the simple processing of low-frequency audio signals.

[0029] To address the aforementioned problems, this application provides an audio low-frequency signal gain control circuit. This circuit can be applied to scenarios where audio low-frequency signals need to be amplified. The input processing sub-circuit preprocesses the input stereo audio signal to obtain a first audio low-frequency signal; then, a non-dynamic low-frequency signal processing sub-circuit processes the first audio low-frequency signal to obtain a non-dynamic audio low-frequency signal; next, a dynamic low-frequency signal processing sub-circuit separates the dynamic audio low-frequency signal from the first audio low-frequency signal; finally, a signal synthesis sub-circuit merges the non-dynamic and dynamic audio low-frequency signals to obtain the audio low-frequency signal; an adaptive gain control sub-circuit controls the gain of the audio low-frequency signal; and a subwoofer outputs the audio low-frequency signal. This solution is applicable to various scenarios, including but not limited to the applications mentioned above.

[0030] The specific circuit will be described in detail below.

[0031] Please see Figure 1 This application also provides an audio low-frequency signal gain control circuit, applied to electronic devices, comprising:

[0032] The input processing sub-circuit 10 is used to preprocess the input stereo audio signal to obtain the first low-frequency audio signal;

[0033] The non-dynamic low-frequency signal processing sub-circuit 20 is connected to the input processing sub-circuit 10 and is used to process the first audio low-frequency signal to obtain a non-dynamic audio low-frequency signal.

[0034] The dynamic low-frequency signal processing sub-circuit 30 is connected to the input processing sub-circuit 10 and is used to separate the dynamic audio low-frequency signal from the first audio low-frequency signal.

[0035] The signal synthesis sub-circuit 40 is connected to the non-dynamic low-frequency signal processing sub-circuit 20 and the dynamic low-frequency signal processing sub-circuit 30, and is used to combine the non-dynamic audio low-frequency signal and the dynamic audio low-frequency signal to obtain an audio low-frequency signal.

[0036] The adaptive gain control sub-circuit 50 is connected to the dynamic low-frequency signal processing sub-circuit 30 and is used to perform adaptive gain control on the audio low-frequency signal to adjust the audio low-frequency signal.

[0037] The woofer 60 is connected to the signal synthesis sub-circuit 40 and is used to output the low-frequency audio signal.

[0038] For example, the input processing sub-circuit 10, the non-dynamic low-frequency signal processing sub-circuit 20, the dynamic low-frequency signal processing sub-circuit 30, the signal synthesis sub-circuit 40, and the adaptive gain control sub-circuit 50 are all analog circuits composed of discrete components.

[0039] In specific implementation, the audio low-frequency signal gain control circuit is mainly used to adaptively gain the audio low-frequency signal in the electronic device. Typically, if the sound pressure level is less than 40dB, the bass frequencies are almost inaudible. Therefore, it is necessary to gain the audio low-frequency signal corresponding to the bass frequencies so that the human ear can clearly hear them. In this embodiment, the input processing sub-circuit 10 receives the stereo audio signal from the audio output terminal, separates the first audio low-frequency signal from the stereo audio signal, and then sets up two circuit branches to obtain the non-dynamic audio low-frequency signal and the dynamic audio low-frequency signal, respectively. Specifically, one of the two circuit branches processes the non-dynamic low-frequency audio signal. The non-dynamic low-frequency signal processing sub-circuit 20 processes the first low-frequency audio signal to obtain a non-dynamic low-frequency audio signal, which is then amplified. The other circuit branch processes the dynamic low-frequency audio signal. The dynamic low-frequency signal processing sub-circuit 30 separates the dynamic low-frequency audio signal from the first low-frequency audio signal and amplifies it. Finally, the non-dynamic and dynamic low-frequency audio signals are combined and amplified to obtain the final low-frequency audio signal, which is the processed stereo audio signal. The adaptive gain control sub-circuit 50 adjusts the dynamic low-frequency audio signal in the other circuit branch, thereby affecting the intensity of the low-frequency audio signal and realizing the adaptive dynamic gain control process. Finally, the low-frequency audio signal with the correct gain is output through the woofer 60 to compensate for bass.

[0040] As can be seen, in this embodiment, adaptive gain of low-frequency audio signals is achieved through analog circuits, which is more targeted and lower in cost compared to the chip implementation method.

[0041] In one possible embodiment, please refer to Figure 2The input processing sub-circuit includes a first signal synthesis unit 101, an AC coupling unit 102, a first low-pass filter unit 103, a first low-frequency amplification unit 104, and a first current-limiting coupling unit 105. The non-dynamic low-frequency signal processing sub-circuit 20 includes a second current-limiting coupling unit 201 and a second low-frequency amplification unit 202. The dynamic low-frequency signal processing sub-circuit 30 includes a second low-pass filter unit 301 and a third low-frequency amplification unit 302. The signal synthesis sub-circuit 40 includes a second signal synthesis unit 401 and the fourth low-frequency amplification unit 402. The first signal synthesis unit 101... The system is used to combine input stereo audio signals into a mono audio signal; an AC coupling unit 102, connected to the first signal synthesis unit 101, is used to AC couple the mono audio signal; a first low-pass filter unit 103, connected to the AC coupling unit 102, is used to separate a second low-frequency audio signal from the mono audio signal; a first low-frequency amplification unit 104, connected to the first low-pass filter unit 103, is used to amplify the second low-frequency audio signal; and a first current-limiting coupling unit 105, connected to the first low-frequency amplification unit 104, is used to amplify the second low-frequency audio signal. The signal is coupled and attenuated to obtain a first low-frequency audio signal; a second current-limiting coupling unit 201, connected to the first current-limiting coupling unit 105, is used to attenuate the first low-frequency audio signal to obtain a non-dynamic low-frequency audio signal; a second low-frequency amplification unit 202, connected to the second current-limiting coupling unit 201, is used to amplify the non-dynamic low-frequency audio signal; a second low-pass filter unit 301, connected to the first current-limiting coupling unit 105, is used to convert the first low-frequency audio signal into a dynamic low-frequency audio signal; a third low-frequency amplification unit 302, connected to the second low-pass filter unit 301... The system comprises: 01 and an adaptive gain control sub-circuit 50, used to amplify the dynamic low-frequency audio signal and adjust the power supply resistance to ground under the control of the adaptive gain control sub-circuit 50; a second signal synthesis unit 401, connected to the third low-frequency amplification unit 302 and the second low-frequency amplification unit 202, used to superimpose the non-dynamic low-frequency audio signal and the dynamic low-frequency audio signal to obtain an audio superimposed signal; and a fourth low-frequency amplification unit 402, connected to the second signal synthesis unit 401 and the subwoofer 60, used to amplify the superimposed signal to obtain an audio low-frequency signal.

[0042] For example, the unit structures included in the input processing sub-circuit 10, the non-dynamic low-frequency signal processing sub-circuit 20, the dynamic low-frequency signal processing sub-circuit 30, and the signal synthesis sub-circuit 40 are not limited to the unit structures in this embodiment, and may be other unit structures that can achieve the same or corresponding functions, without being limited to uniqueness here.

[0043] As can be seen, in this embodiment, preprocessing of low-frequency audio signals is achieved through multiple analog circuit units.

[0044] In one possible embodiment, please refer to Figure 3 The adaptive gain control sub-circuit 50 includes: a third current-limiting coupling unit 501 connected to the fourth low-frequency amplification unit 402, used for coupling and attenuating the audio low-frequency signal; a third low-pass filter unit 502 connected to the third current-limiting coupling unit 501, used for separating the adaptive audio low-frequency signal from the attenuated audio low-frequency signal; a fifth low-frequency amplification unit 503 connected to the third low-pass filter unit 502, used for amplifying the adaptive audio low-frequency signal; a rectification filter unit 504 connected to the fifth low-frequency amplification unit 503, used for filtering and rectifying the amplified first dynamic audio low-frequency signal to obtain a DC voltage; and a multi-stage switching unit 505 connected to the rectification filter unit 504 and the third low-frequency amplification unit 302, used to control the gain of the audio low-frequency signal by changing the resistance to ground at the power supply terminal of the third low-frequency amplification unit 302 under the control of the DC voltage.

[0045] For example, the unit structure of the adaptive gain control sub-circuit 50 is not limited to the unit structure in this embodiment, but can also be other unit structures that can achieve the same or corresponding functions, and is not limited to uniqueness here.

[0046] As can be seen, in this embodiment, automatic gain control of low-frequency audio signals is achieved through multiple analog circuit units in the adaptive gain control sub-circuit 50.

[0047] In one possible embodiment, please refer to Figure 4 and Figure 5The first signal synthesis unit 101 includes a first resistor R1 and a second resistor R2; the AC coupling unit 102 includes a first capacitor C1; the first low-pass filter unit 103 includes a third resistor R3, a fourth resistor R4, and a second capacitor C2; the first low-frequency amplification unit 104 includes a fifth resistor R5, a sixth resistor R6, and a first transistor Q1; the first current-limiting coupling unit 105 includes a seventh resistor R7 and a third capacitor C3; the second current-limiting coupling unit 201 includes an eighth resistor R8 and a fourth capacitor C4; and the second low-pass filter unit 301... The second low-frequency amplification unit 202 includes a ninth resistor R9, a tenth resistor R10, and a fifth capacitor C5; the third low-frequency amplification unit 302 includes an eleventh resistor R11, a twelfth resistor R12, and a second transistor Q2; the fourth low-frequency amplification unit 302 includes a fourteenth resistor R14, a fifteenth resistor R15, and a third transistor Q3; the second signal synthesis unit 401 includes a thirteenth resistor R13, a sixteenth resistor R16, and a sixth capacitor C6; and the fourth low-frequency amplification unit 402 includes a seventeenth resistor R17, an eighteenth resistor R18, a seventh capacitor C7, and a fourth transistor Q4.

[0048] One end of the first resistor R1 is connected to the left channel output terminal L-IN, one end of the second resistor R2 is connected to the right channel output terminal R-IN, the other ends of the first resistor R1 and the other ends of the second resistor R2 are connected to one end of the first capacitor C1, and the other end of the first capacitor C1 is connected to one end of the third resistor R3.

[0049] The other end of the third resistor R3 is connected to one end of the second capacitor C2 and one end of the fourth resistor R4, the other end of the second capacitor C2 is grounded, the other end of the fourth resistor R4 is connected to one end of the fifth resistor R5 and the base of the first transistor Q1, the other end of the fifth resistor R5 is connected to one end of the sixth resistor R6, one end of the seventh resistor R7 and the collector of the first transistor Q1, the other end of the sixth resistor R6 is connected to the first power supply VDD, the emitter of the first transistor Q1 is grounded, and the other end of the seventh resistor R7 is connected to one end of the third capacitor C3;

[0050] The other end of the third capacitor C3 is connected to one end of the eighth resistor R8 and one end of the ninth resistor R9, respectively. The other end of the eighth resistor R8 is connected to one end of the fourth capacitor C4. The other end of the fourth capacitor C4 is connected to one end of the eleventh resistor R11 and the base of the second transistor Q2, respectively. The other end of the eleventh resistor R11 is connected to the collector of the second transistor Q2, one end of the twelfth resistor R12 and one end of the thirteenth resistor R13, respectively. The other end of the twelfth resistor R12 is connected to the first power supply VDD, and the emitter of the second transistor Q2 is grounded.

[0051] The other end of the ninth resistor R9 is connected to one end of the tenth resistor R10 and one end of the fifth capacitor C5. The other end of the fifth capacitor C5 is grounded. The other end of the tenth resistor R10 is connected to one end of the fourteenth resistor R14 and the base of the third transistor Q3. The other end of the fourteenth resistor R14 is connected to the collector of the third transistor Q3, one end of the fifteenth resistor R15, and one end of the sixteenth resistor R16. The other end of the fifteenth resistor R15 is connected to the adaptive gain control sub-circuit 50.

[0052] The other ends of the thirteenth resistor R13 and the sixteenth resistor R16 are respectively connected to one end of the seventeenth resistor R17 and the base of the fourth transistor Q4. The other end of the seventeenth resistor R17 is connected to the collector of the fourth transistor Q4, one end of the eighteenth resistor R18 and one end of the seventh capacitor C7. The other end of the eighteenth resistor R18 is connected to the first power supply VDD, and the other end of the seventh capacitor C7 is connected to the adaptive gain control sub-circuit 50.

[0053] In a specific implementation, the audio output terminal includes a left channel output terminal L-IN and a right channel output terminal R-IN. The stereo audio signal includes a left channel audio signal and a right channel audio signal. The L-IN outputs the left channel audio signal, and the right channel output terminal R-IN outputs the right channel audio signal.

[0054] Specifically, in this embodiment, the left channel audio signal is input from the left channel output terminal L-IN via the first resistor R1, and the right channel audio signal is input from the right channel output terminal R-IN via the second resistor R2. Then, the left channel audio signal and the right channel audio signal are coupled into a mono audio signal via the first capacitor C1. Then, the signal is processed by the first low-pass filter unit 103 composed of the third resistor R3, the fourth resistor R4, and the second capacitor C2 to separate the second low-frequency audio signal. The second low-frequency audio signal is amplified by the first low-frequency amplifier circuit composed of the fifth resistor R5, the sixth resistor R6, and the first transistor Q1, making it easier for subsequent circuits to process the first low-frequency audio signal. After the first low-frequency audio signal is current-limited and coupled by the seventh resistor R7 and the third capacitor C3, the first low-frequency audio signal is attenuated. Then, the attenuated first low-frequency audio signal is divided into two routes and processed by two circuit branches.

[0055] One of the circuit branches consists of the second current-limiting coupling unit 201 and the second low-frequency amplification unit 202. The second current-limiting coupling unit 201, which consists of the eighth resistor R8 and the fourth capacitor C4, limits and attenuates the attenuated first audio low-frequency signal again to obtain a non-dynamic audio low-frequency signal NON-DYNAMIC_BASS. The non-dynamic audio low-frequency signal NON-DYNAMIC_BASS is then amplified by the second low-frequency amplification circuit, which consists of the eleventh resistor R11, the twelfth resistor R12 and the second transistor Q2, to obtain the amplified non-dynamic audio low-frequency signal NON-DYNAMIC_BASS.

[0056] Another circuit branch consists of the second low-pass filter unit 301 and the third low-frequency amplifier unit 302; wherein, the second low-pass filter circuit, composed of the ninth resistor R9, the tenth resistor R10 and the fifth capacitor C5, separates the dynamic audio low-frequency signal DYNAMIC_BASS from the first audio low-frequency signal, and then the third low-frequency amplifier unit 302, composed of the fourteenth resistor R14, the fifteenth resistor R15 and the third transistor Q3, amplifies the dynamic audio low-frequency signal DYNAMIC_BASS.

[0057] Furthermore, after obtaining the non-dynamic low-frequency audio signal NON-DYNAMIC_BASS and the dynamic low-frequency audio signal DYNAMIC_BASS, the second signal synthesis unit 401 merges the non-dynamic low-frequency audio signal NON-DYNAMIC_BASS and the dynamic low-frequency audio signal DYNAMIC_BASS. Then, the fourth low-frequency amplification unit 402 amplifies the merged audio signal to obtain the low-frequency audio signal BASS-OUT, which is output from the woofer 60 to compensate for bass frequencies. The dynamic low-frequency audio signal DYNAMIC_BASS changes according to the adaptive gain control sub-circuit 50 to achieve adaptive gain control of the low-frequency audio signal BASS-OUT.

[0058] As can be seen, in this embodiment, the low-frequency audio signal BASS-OUT is separated, and a dynamically changing dynamic low-frequency audio signal DYNAMIC_BASS and a fixed non-dynamic low-frequency audio signal NON-DYNAMIC_BASS are set, so that the final synthesized low-frequency audio signal BASS-OUT can achieve the purpose of automatic gain.

[0059] In one possible embodiment, please refer to Figure 6The third current-limiting coupling unit 501 includes a nineteenth resistor R19 and an eighth capacitor C8; the third low-pass filter unit 502 includes a twentieth resistor R20, a twenty-first resistor R21 and a ninth capacitor C9; the fifth low-frequency amplification unit 503 includes a twenty-second resistor R22, a twenty-third resistor R23 and a fifth transistor Q5; the rectifier filter unit 504 includes a tenth capacitor C10, a first diode and a second diode; and the multi-stage switching unit 505 includes multiple common-emitter transistor switching units.

[0060] The other end of the seventh capacitor C7, the nineteenth resistor R19, the eighth capacitor C8, and one end of the twentieth resistor R20 are connected in sequence. The other end of the twentieth resistor R20 is connected to one end of the twenty-first resistor R21 and one end of the ninth capacitor C9. The other end of the ninth capacitor C9 is grounded. The other end of the twenty-first resistor R21 is connected to one end of the twenty-second resistor R22 and the base of the fifth transistor Q5. The other end of the twenty-second resistor R22 is connected to the collector of the fifth transistor Q5, one end of the twenty-third resistor R23, and one end of the tenth capacitor C10. The other end of the twenty-third resistor R23 is connected to the first power supply VDD. The emitter of the fifth transistor Q5 is grounded. The other end of the tenth capacitor C10 is connected to the anode of the first diode D1 and the cathode of the second diode D2. The anode of the second diode D2 is grounded. The cathode of the first diode D1 is connected to the plurality of transistor switching units. The plurality of transistor switching units are all connected to the other end of the fifteenth resistor R15.

[0061] For example, the voltage of the first power supply VDD is 5V. However, different first power supply VDDs can be adapted to specific electronic devices, and no unique limitation is made here.

[0062] The adaptive gain control process for dynamic bass audio signals is explained below.

[0063] Specifically, the low-frequency audio signal BASS-OUT, amplified by the fourth transistor Q4, is output to the nineteenth resistor R19. The nineteenth resistor R19 and the eighth capacitor C8 limit and couple the low-frequency audio signal BASS-OUT before outputting it to the third low-pass filter unit 502. The twentieth resistor R20, the twenty-first resistor R21, and the ninth capacitor C9 perform low-pass filtering to obtain the adaptive low-frequency audio signal BASS-OUT. This signal is then amplified by the fifth transistor Q5, coupled by the tenth capacitor C10, and finally rectified by the first and second diodes to obtain a DC voltage. This DC voltage controls the switching state of the multiple transistor switching units, thereby changing the voltage at the collector of the fifteenth resistor R15 in the third low-frequency amplifier circuit. Since the collector voltage of the fifteenth resistor R15 has changed, the gain of the final synthesized low-frequency audio signal BASS-OUT also changes with the change in the collector power supply, thus realizing the adaptive dynamic gain control process.

[0064] Furthermore, Figure 6 An example of three transistor switching units is shown, but it is understood that the number of transistor switching units is not limited to three and can be increased or decreased according to gain requirements. No uniqueness is specified here.

[0065] As can be seen, in this embodiment, adaptive dynamic gain control of the low-frequency audio signal BASS-OUT is achieved.

[0066] In one possible embodiment, please continue reading Figure 6 Each of the plurality of transistor switching units includes a twenty-fourth resistor R24, a twenty-fifth resistor R25, a twenty-sixth resistor R26, and a sixth transistor Q6;

[0067] One end of the 24th resistor R24 ​​is connected to the cathode of the first diode D1. The other end of the 24th resistor is connected to one end of the 25th resistor R25 and the base of the sixth transistor Q6. The other end of the 25th resistor R25 is grounded. The collector of the sixth transistor Q6 is connected to one end of the 26th resistor R26. The emitter of the sixth transistor Q6 is grounded. The other end of the 26th resistor R26 is connected to the first power supply VDD and the other end of the 15th resistor R15.

[0068] In specific implementation, the sixth transistor Q6 in the transistor switching unit is turned on or off depending on the magnitude of the dynamic audio low-frequency signal DYNAMIC_BASS. When the dynamic audio low-frequency signal DYNAMIC_BASS is greater than the conduction threshold of the sixth transistor Q6, the sixth transistor Q6 is turned on; when the dynamic audio low-frequency signal DYNAMIC_BASS is less than the conduction threshold of the sixth transistor Q6, the sixth transistor Q6 is turned off. Thus, the gain of the audio low-frequency signal BASS-OUT can be controlled according to specific circumstances.

[0069] As can be seen, in this embodiment, by controlling the switching state of the transistor switching unit according to the dynamic low-frequency audio signal DYNAMIC_BASS, adaptive gain of the low-frequency audio signal BASS-OUT is achieved.

[0070] This application also provides an audio low-frequency signal gain control device, applied to an electronic device, including the audio low-frequency signal gain control circuit as described in the first aspect. Specifically, the device can be any audio device, such as a speaker, headphones, a voice recorder, an MP3 player, a mobile phone, etc., and is not limited to a single type. Since the audio low-frequency signal gain control circuit has been described in detail above, it will not be repeated here.

[0071] This application also provides an audio device, including the audio low-frequency signal gain control circuit as described in the first aspect. Specifically, the device can be any audio device, such as a speaker, headphones, a voice recorder, an MP3 player, a mobile phone, etc., and is not limited to a single type. Since the audio low-frequency signal gain control circuit has been described in detail above, it will not be repeated here.

[0072] This application also provides an electronic device, including the audio low-frequency signal gain control circuit as described in the first aspect. Specifically, the device can be any audio device, such as a speaker, headphones, a voice recorder, an MP3 player, a mobile phone, a computer, etc., and is not limited to a single type. Since the audio low-frequency signal gain control circuit has been described in detail above, it will not be repeated here.

[0073] In the several embodiments provided in this application, it should be understood that the disclosed methods, apparatuses, and systems can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for example, the division of units is merely a logical functional division, and other division methods may exist in actual implementation; for example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces, and the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0074] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0075] In addition, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can be physically included separately, or two or more units can be integrated into one unit.

[0076] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can easily conceive of variations or substitutions without departing from the spirit and scope of the present invention, and various modifications and alterations can be made, including combinations of the different functions and implementation steps described above, as well as software and hardware implementation methods, all of which are within the protection scope of the present invention.

Claims

1. An audio low-frequency signal gain control circuit, characterized in that, Applied to electronic devices, including: The input processing sub-circuit is used to preprocess the input stereo audio signal to obtain the first low-frequency audio signal; A non-dynamic low-frequency signal processing sub-circuit, connected to the input processing sub-circuit, is used to process the first audio low-frequency signal to obtain a non-dynamic audio low-frequency signal; A dynamic low-frequency signal processing sub-circuit, connected to the input processing sub-circuit, is used to separate the dynamic audio low-frequency signal from the first audio low-frequency signal; A signal synthesis sub-circuit, connected to the non-dynamic low-frequency signal processing sub-circuit and the dynamic low-frequency signal processing sub-circuit, is used to combine the non-dynamic audio low-frequency signal and the dynamic audio low-frequency signal to obtain an audio low-frequency signal; An adaptive gain control subcircuit, connected to the dynamic low-frequency signal processing subcircuit, is used to adaptively control the gain of the audio low-frequency signal and adjust the audio low-frequency signal. The adaptive gain control subcircuit includes: a third current-limiting coupling unit, connected to the signal synthesis subcircuit, used to couple and attenuate the audio low-frequency signal; a third low-pass filtering unit, connected to the third current-limiting coupling unit, used to separate the adaptive dynamic audio low-frequency signal from the attenuated audio low-frequency signal; a fifth low-frequency amplification unit, connected to the third low-pass filtering unit, used to amplify the adaptive dynamic audio low-frequency signal; a rectification and filtering unit, connected to the fifth low-frequency amplification unit, used to filter and rectify the amplified adaptive dynamic audio low-frequency signal to obtain a DC voltage; and a multi-stage switching unit, connected to the rectification and filtering unit and the dynamic low-frequency signal processing subcircuit, used to change the resistance to ground at the power supply terminal of the third low-frequency amplification unit under the control of the DC voltage, thereby changing the power supply terminal voltage of the dynamic low-frequency signal processing subcircuit to control the gain of the audio low-frequency signal. A subwoofer, connected to the signal synthesis sub-circuit, is used to output the low-frequency audio signal.

2. The circuit according to claim 1, characterized in that, The input processing sub-circuit includes a first signal synthesis unit, an AC coupling unit, a first low-pass filter unit, a first low-frequency amplification unit, and a first current-limiting coupling unit. The non-dynamic low-frequency signal processing sub-circuit includes a second current-limiting coupling unit and a second low-frequency amplification unit. The dynamic low-frequency signal processing sub-circuit includes a second low-pass filter unit and a third low-frequency amplification unit. The signal synthesis sub-circuit includes a second signal synthesis unit and a fourth low-frequency amplification unit. The first signal synthesis unit is used to combine the input stereo audio signal into a mono audio signal; An AC coupling unit, connected to the first signal synthesis unit, is used to AC couple the mono audio signal. A first low-pass filter unit, connected to the AC coupling unit, is used to separate a second low-frequency audio signal from the mono audio signal; The first low-frequency amplification unit is connected to the first low-pass filter unit and is used to amplify the second low-frequency audio signal; The first current-limiting coupling unit is connected to the first low-frequency amplification unit and is used to couple and attenuate the amplified second audio low-frequency signal to obtain the first audio low-frequency signal. The second current-limiting coupling unit is connected to the first current-limiting coupling unit and is used to attenuate the first audio low-frequency signal to obtain a non-dynamic audio low-frequency signal. The second low-frequency amplification unit is connected to the second current-limiting coupling unit and is used to amplify the non-dynamic audio low-frequency signal; The second low-pass filter unit is connected to the first current-limiting coupling unit and is used to convert the first low-frequency audio signal into a dynamic low-frequency audio signal. The third low-frequency amplification unit is connected to the second low-pass filter unit and the adaptive gain control sub-circuit. It is used to amplify the dynamic audio low-frequency signal and is controlled by the adaptive gain control sub-circuit to adjust the power supply terminal to ground resistance. The second signal synthesis unit is connected to the third low-frequency amplification unit and the second low-frequency amplification unit, and is used to superimpose the non-dynamic audio low-frequency signal and the dynamic audio low-frequency signal to obtain an audio superimposed signal; The fourth low-frequency amplification unit is connected to the second signal synthesis unit and the subwoofer, and is used to amplify the superimposed signal to obtain a low-frequency audio signal.

3. The circuit according to claim 2, characterized in that, The first signal synthesis unit includes a first resistor and a second resistor; the AC coupling unit includes a first capacitor; the first low-pass filter unit includes a third resistor, a fourth resistor, and a second capacitor; the first low-frequency amplification unit includes a fifth resistor, a sixth resistor, and a first transistor; the first current-limiting coupling unit includes a seventh resistor and a third capacitor; the second current-limiting coupling unit includes an eighth resistor and a fourth capacitor; the second low-pass filter unit includes a ninth resistor, a tenth resistor, and a fifth capacitor; the second low-frequency amplification unit includes an eleventh resistor, a twelfth resistor, and a second transistor; the third low-frequency amplification unit includes a fourteenth resistor, a fifteenth resistor, and a third transistor; the second signal synthesis unit includes a thirteenth resistor, a sixteenth resistor, and a sixth capacitor; and the fourth low-frequency amplification unit includes a seventeenth resistor, an eighteenth resistor, a seventh capacitor, and a fourth transistor. One end of the first resistor is connected to the left channel output terminal, one end of the second resistor is connected to the right channel output terminal, the other ends of the first resistor and the other ends of the second resistor are connected to one end of the first capacitor, and the other end of the first capacitor is connected to one end of the third resistor. The other end of the third resistor is connected to one end of the second capacitor and one end of the fourth resistor, the other end of the second capacitor is grounded, the other end of the fourth resistor is connected to one end of the fifth resistor and the base of the first transistor, the other end of the fifth resistor is connected to one end of the sixth resistor, one end of the seventh resistor and the collector of the first transistor, the other end of the sixth resistor is connected to the first power supply, the emitter of the first transistor is grounded, and the other end of the seventh resistor is connected to one end of the third capacitor. The other end of the third capacitor is connected to one end of the eighth resistor and one end of the ninth resistor, respectively. The other end of the eighth resistor is connected to one end of the fourth capacitor. The other end of the fourth capacitor is connected to one end of the eleventh resistor and the base of the second transistor, respectively. The other end of the eleventh resistor is connected to the collector of the second transistor, one end of the twelfth resistor, and one end of the thirteenth resistor, respectively. The other end of the twelfth resistor is connected to the first power supply, and the emitter of the second transistor is grounded. The other end of the ninth resistor is connected to one end of the tenth resistor and one end of the fifth capacitor, the other end of the fifth capacitor is grounded, the other end of the tenth resistor is connected to one end of the fourteenth resistor and the base of the third transistor, the other end of the fourteenth resistor is connected to the collector of the third transistor, one end of the fifteenth resistor and one end of the sixteenth resistor, and the other end of the fifteenth resistor is connected to the adaptive gain control sub-circuit. The other ends of the thirteenth resistor and the sixteenth resistor are both connected to one end of the sixth capacitor. The other end of the sixth capacitor is connected to one end of the seventeenth resistor and the base of the fourth transistor. The other end of the seventeenth resistor is connected to the collector of the fourth transistor, one end of the eighteenth resistor, and one end of the seventh capacitor. The other end of the eighteenth resistor is connected to the first power supply. The other end of the seventh capacitor is connected to the adaptive gain control sub-circuit.

4. The circuit according to claim 3, characterized in that, The third current-limiting coupling unit includes a nineteenth resistor and an eighth capacitor; the third low-pass filter unit includes a twentieth resistor, a twenty-first resistor, and a ninth capacitor; the fifth low-frequency amplification unit includes a twenty-second resistor, a twenty-third resistor, and a fifth transistor; the rectifier filter unit includes a tenth capacitor, a first diode, and a second diode; and the multi-stage switching unit includes multiple common-emitter transistor switching units. The other end of the seventh capacitor, the nineteenth resistor, the eighth capacitor, and one end of the twentieth resistor are connected in sequence. The other end of the twentieth resistor is connected to one end of the twentieth resistor and one end of the ninth capacitor. The other end of the ninth capacitor is grounded. The other end of the twentieth resistor is connected to one end of the twentieth resistor and the base of the fifth transistor. The other end of the twentieth resistor is connected to the collector of the fifth transistor, one end of the twentieth resistor, and one end of the tenth capacitor. The other end of the twentieth resistor is connected to the first power supply. The emitter of the fifth transistor is grounded. The other end of the tenth capacitor is connected to the anode of the first diode and the cathode of the second diode. The anode of the second diode is grounded. The cathode of the first diode is connected to the plurality of transistor switching units. The plurality of transistor switching units are all connected to the other end of the fifteenth resistor.

5. The circuit according to claim 4, characterized in that, Each of the plurality of transistor switching units includes a 24th resistor, a 25th resistor, a 26th resistor, and a 6th transistor; One end of the 24th resistor is connected to the cathode of the first diode, and the other end of the 24th resistor is connected to one end of the 25th resistor and the base of the sixth transistor. The other end of the 25th resistor is grounded. The collector of the sixth transistor is connected to one end of the 26th resistor, and the emitter of the sixth transistor is grounded. The other end of the 26th resistor is connected to the first power supply and the other end of the 15th resistor.

6. The circuit according to claim 3 or 4, characterized in that, The voltage of the first power supply is 5V.

7. An audio low-frequency signal gain control device, characterized in that, Applied to electronic devices, including the audio low-frequency signal gain control circuit as described in any one of claims 1-6.

8. An audio device, characterized in that, Includes the audio low-frequency signal gain control circuit as described in any one of claims 1-6.

9. An electronic device, characterized in that, Includes the audio low-frequency signal gain control circuit as described in any one of claims 1-6.

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