CN217770035U - Low-frequency enhancement circuit and audio playing device - Google Patents
Low-frequency enhancement circuit and audio playing device Download PDFInfo
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- CN217770035U CN217770035U CN202221438633.7U CN202221438633U CN217770035U CN 217770035 U CN217770035 U CN 217770035U CN 202221438633 U CN202221438633 U CN 202221438633U CN 217770035 U CN217770035 U CN 217770035U
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Abstract
The application discloses a low-frequency enhancing circuit of a low-frequency enhancing circuit, which comprises a signal receiving circuit, an audio power amplifying circuit, a low-frequency feedback circuit and an audio output circuit; the signal receiving circuit is used for receiving an audio signal sent by external audio equipment; the audio power amplifying circuit is connected with the signal receiving circuit and is used for receiving the audio signal sent by the signal receiving circuit and carrying out power amplification; the low-frequency feedback circuit is connected with the audio power amplifying circuit and is used for feeding back the audio signal output by the audio power amplifying circuit to the audio power amplifying circuit; the audio output circuit is connected with the audio power amplifying circuit and is used for outputting the audio signal amplified by the audio power amplifying circuit; furthermore, the low-frequency enhancing circuit can directly play the audio signals with the frequency of the low frequency band of 50HZ-150HZ to be beneficial to sleep aiding, and meanwhile, the low-frequency enhancing circuit can be used for enhancing the audio signals with the low frequency band in the common audio signals to enable the enhanced low-frequency signals to help users to sleep.
Description
Technical Field
The application relates to the field of music sleep aiding, in particular to a low-frequency enhancement circuit and an audio playing device.
Background
Modern people's life rhythm is fast and life pressure is big, causes the difficulty of falling asleep, and music helps dormancy equipment can help people fall asleep relatively fast to satisfy people's normal life and the energy demand of work.
The music sleep-aiding equipment is specially used for playing low-frequency audio of 50HZ-150HZ to aid sleep; but cannot enhance the low frequency band of 50HZ-150HZ that contributes to sleep in normal audio.
SUMMERY OF THE UTILITY MODEL
The embodiment of the application provides a low frequency enhancement circuit and audio playing device, can strengthen the low-frequency audio frequency that helps sleep in the ordinary audio frequency, and then can help effectively sleeping.
In a first aspect, the present application provides a low frequency enhancement circuit, comprising:
the signal receiving circuit is used for receiving an audio signal sent by external audio equipment;
the audio power amplifying circuit is connected with the signal receiving circuit and used for receiving the audio signal sent by the signal receiving circuit and carrying out power amplification;
the low-frequency feedback circuit is connected with the audio power amplifying circuit and is used for feeding the audio signal output by the audio power amplifying circuit back to the audio power amplifying circuit so as to enable the audio power amplifying circuit to perform power amplification on the low-frequency signal in the audio signal, wherein the frequency of the low-frequency signal is greater than or equal to 50Hz and less than or equal to 150Hz;
and the audio output circuit is connected with the audio power amplifying circuit and is used for outputting the audio signal amplified by the audio power amplifying circuit.
In some of these embodiments, the low frequency boost circuit further comprises:
the low-frequency feedback circuit is connected with the audio power amplifying circuit through the selective switch circuit; when the audio signal is an audio signal of common music, the selection switch circuit is switched on, so that the low-frequency feedback circuit feeds back the low-frequency signal to the audio power amplifying circuit through the selection switch circuit; when the audio signal is the audio signal of the sleep-aid music, the selection switch circuit is closed.
In some embodiments, the selection switch circuit is turned on or off according to the type of the received audio signal, or the selection switch circuit is turned on or off according to a user-triggered instruction.
IN some of these embodiments, the audio power amplification circuit has a first pin (IN +) for receiving an audio signal, a second pin (OUT) for outputting an audio signal, and a third pin (AV) for connecting with the selection switch circuit;
a first pin (IN +) of the audio power amplifying circuit is connected with the signal receiving circuit;
the second pin (OUT) of the audio power amplifying circuit is connected with the audio output circuit so as to transmit the processed audio signal to the audio output circuit.
In some embodiments, the selection switch circuit has a first pin (B1) and a second pin (a), the low frequency feedback circuit is connected between the second pin (OUT) of the audio power amplification circuit and the first pin (B1) of the selection switch circuit, and the third pin (AV) of the audio power amplification circuit is connected with the second pin (a) of the selection switch circuit.
In some embodiments, the low frequency feedback circuit comprises a first capacitor (C3) and a first resistor (R8) connected in series with the first capacitor (C3), and the second pin (OUT) of the audio power amplifying circuit is connected to the first pin (B1) of the selection switch circuit through the first capacitor (C3) and the first resistor (R8).
In some of these embodiments, the audio output circuit comprises a second capacitance (C20) and an output port (CN 1) connected to the second capacitance (C20);
the output port (CN 1) comprises a first pin (D1) and a second pin (D2), the first pin (D1) of the output port is connected with a second pin (OUT) of the audio power amplifying circuit through the second capacitor (C20), the second pin (D2) is grounded, and the first pin (D1) and the second pin (D2) are further used for being connected with an external loudspeaker and/or an external bone conduction vibrator.
In some of these embodiments, the signal receiving circuit comprises a third capacitor (C15), a fourth capacitor (C29), and a second resistor (R9);
the third capacitor (C15) comprises a first end and a second end, and the first end of the third capacitor (C15) is used for being connected with an external audio device so as to be coupled with an analog signal input by the external audio device;
the second end of the third capacitor (C15) is provided with three paths, and the first path of the second end of the third capacitor (C15) is connected with the first pin (IN +) of the audio power amplifying circuit;
a second path of the second end of the third capacitor (C15) is grounded through the fourth capacitor (C29);
the third path of the second end of the third capacitor (C15) is grounded through the second resistor (R9), so that the first pin (IN +) of the audio power amplifying circuit is IN a low level state, and the noise IN the analog signal is reduced.
In some embodiments, the low frequency enhancement circuit further comprises a fifth capacitor (C5), the audio power amplification circuit further has a fourth pin (DET), and the fourth pin (DET) of the audio power amplification circuit is grounded through the fifth capacitor (C5) to filter noise generated during transmission of the audio signal.
In some embodiments, the low frequency enhancement circuit further comprises a sixth capacitor (C6), the audio power amplification circuit further has a fifth pin (VDD), and the fifth pin (VDD) of the audio power amplification circuit is grounded through the sixth capacitor (C6) to store energy at the moment when the audio power amplification circuit is powered on and deliver the stored energy to the audio output circuit.
In some embodiments, the low frequency enhancement circuit further includes a seventh capacitor (C2) and a third resistor (R4), and the second pin (OUT) of the audio power amplification circuit is further grounded through the seventh capacitor (C2) and the third resistor (R4) to block an ac voltage output by the audio power amplification circuit, so as to avoid damage to a speaker and/or a bone conduction vibrator connected to the audio output circuit.
In a second aspect, the present application provides an audio playing apparatus, which includes the above-mentioned low frequency enhancement circuit.
Based on the low-frequency enhancement circuit provided by the embodiment of the application, the low-frequency enhancement circuit can directly play the audio signal with the frequency of 50HZ-150HZ low frequency band so as to be beneficial to sleep, and meanwhile, the low-frequency enhancement circuit can be used for enhancing the audio signal with the low frequency band in the common audio signal so as to enable the enhanced low-frequency signal to help a user to sleep.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative efforts.
FIG. 1 is a block diagram of an overall low frequency enhancement circuit according to an embodiment of the present application;
FIG. 2 is a circuit diagram of an LM386M power amplifier in one embodiment of the present application;
FIG. 3 is a circuit diagram of an SGM3157 analog switch according to one embodiment of the present application;
FIG. 4 is a circuit diagram of a power supply circuit according to an embodiment of the present application;
FIG. 5 is a circuit diagram of a low frequency feedback circuit in an embodiment of the present application;
FIG. 6 is a circuit diagram of a second capacitor according to an embodiment of the present application;
FIG. 7 is a circuit diagram of an output port according to an embodiment of the present application;
FIG. 8 is a circuit diagram of a signal receiving circuit according to an embodiment of the present application;
FIG. 9 is a schematic circuit diagram of a fifth capacitor according to an embodiment of the present application;
FIG. 10 is a schematic diagram of a connection circuit of a sixth capacitor according to an embodiment of the present application;
FIG. 11 is a schematic diagram of a connection circuit of a seventh capacitor and a third resistor according to an embodiment of the present application;
fig. 12 is an overall circuit diagram of a low frequency enhancement circuit according to an embodiment of the present application.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.
Modern people's life rhythm is fast and life pressure is big, causes the difficulty of falling asleep, and music helps dormancy equipment can help people fall asleep relatively fast to satisfy people's normal life and the energy demand of work.
The music sleep-aiding equipment is specially used for playing low-frequency audio of 50HZ-150HZ to aid sleep; but cannot enhance the low frequency band of 50HZ-150HZ that contributes to sleep in normal audio.
In order to solve the above problem, in a first aspect, please refer to fig. 1, the present application provides a low frequency enhancement circuit, which includes a signal receiving circuit 2, an audio power amplifying circuit 1, a low frequency feedback circuit 5, and an audio output circuit 3.
The signal receiving circuit 2 is configured to receive an audio signal transmitted by an external audio device in a wireless manner, for example, the external audio device may be transmitted through a bluetooth transmitting unit, and the signal receiving circuit 2 may be configured with a bluetooth receiving unit, so that the audio signal transmitted by the bluetooth transmitting unit may be received by the bluetooth receiving unit; external audio equipment can also transmit audio signals to signal receiving circuit 2 through WIFI signal transmission technology, and external audio equipment can also transmit audio signals to signal receiving circuit 2 in a wired manner, for example: the external audio device is a mobile terminal, such as a mobile phone or a music player, and the mobile phone or the music player can convert an audio signal into an electrical signal and transmit the audio signal to the signal receiving circuit 2 through a signal transmission line. The audio output by the external audio equipment can be common audio, and the common audio comprises low-frequency-band audio, middle-frequency-band audio and high-frequency-band audio; the low-band audio may also include sleep-aid audio at frequencies in the low-band of 50HZ-150 HZ.
The audio power amplifying circuit 1 is electrically connected to the signal receiving circuit 2, and is configured to receive an audio signal sent by the signal receiving circuit 2 and perform power amplification on the received audio signal, the audio output circuit 3 is connected to the audio power amplifying circuit 1, and is configured to output the audio signal processed by the audio power amplifying circuit 1, and the audio output circuit 3 may include a load, such as a speaker and a bone conduction vibrator.
The audio power amplifying circuit 1 can amplify the audio signal transmitted by the signal receiving circuit 2 without distortion, and output the audio signal with sufficient power to drive the load to make a sound or generate vibration. The audio power amplifier circuit 1 may include a pre-amplifier circuit (not shown) and a power amplifier circuit (not shown), the pre-amplifier circuit may include a voltage amplifier, and the voltage amplifier may amplify the amplitude of the audio signal; the power amplifying circuit can amplify the power of the audio signal, so that the audio signal after power amplification can drive a load to make a sound or generate vibration. It should be noted that the power amplifying circuit is an energy conversion circuit, and the power amplifying circuit can output an audio signal with a larger power within a distortion allowable range, so that the audio signal with the larger power can drive the load to make a sound or generate vibration.
The low-frequency enhancement circuit also comprises a low-frequency feedback circuit 5, wherein the low-frequency feedback circuit 5 is positioned between the power amplification circuit and the pre-amplification circuit and is used for connecting the power amplification circuit and the pre-amplification circuit; the low-frequency feedback circuit 5 is used for feeding back the audio signal output by the power amplifying circuit to the pre-amplifying circuit. When the audio signal received by the low-frequency feedback circuit 5 is a low-frequency signal (the frequency is in a low-frequency range of 50HZ-150 HZ), the pre-amplification circuit does not process the audio signal output by the power amplification circuit; when the audio signal received by the low frequency feedback circuit 5 is a normal audio signal (the normal audio signal includes a low frequency band audio, a middle frequency band audio and a high frequency band audio), the pre-amplifier circuit may amplify the amplitude of the low frequency band audio signal with a frequency of 50HZ to 150HZ in the normal audio signal, so as to enhance the low frequency band audio signal in the normal audio signal.
Further, the low frequency enhancement circuit may further include a selection switch circuit 4, and the low frequency feedback circuit 5 is connected to the preamplifier circuit through the selection switch circuit 4. When the audio signal output by the power amplifying circuit is a common audio signal (the common audio signal includes a low-frequency band audio, a middle-frequency band audio and a high-frequency band audio), the selection switch circuit 4 is turned on, so that the low-frequency feedback circuit 5 feeds back the low-frequency signal to the pre-amplifying circuit through the selection switch circuit 4, so that the pre-amplifying circuit amplifies the amplitude of the low-frequency band of the low-frequency signal in the range of 50HZ to 150HZ, and enhances the low-frequency signal in the common audio, so that the power amplifying circuit outputs the audio signal of which the bass enhanced frequency is in the low-frequency band of 50HZ to 150HZ, and the audio signal is helpful for sleeping. When the audio signal is a low-frequency signal (with a frequency in a low frequency range of 50HZ to 150 HZ) of the sleep-aid music, the selection switch circuit 4 is turned off, and the power amplification circuit directly enhances the low-frequency signal, so that the low-frequency signal after power enhancement can well drive the load, the load can make a sound or generate vibration to be received by the user, and the sleep of the user can be facilitated.
Further, the selection switch circuit 4 is turned on or off according to the type of the received audio signal, specifically, when the audio signal is a normal audio signal, the selection switch circuit 4 is turned on, and the pre-amplification circuit amplifies the amplitude of a low-frequency signal in the normal audio; when the audio signal is the low-frequency signal of the sleep-aiding music, the selection switch circuit 4 is closed, the power amplification circuit directly amplifies the audio signal of the sleep-aiding music, and the load is driven to make a sound or generate vibration to be received by a user, so that the user can sleep.
In some embodiments, the selection switch circuit 4 may also be turned on or off according to an instruction triggered by a user, specifically, when the audio signal is a normal audio signal, the user triggers the selection switch circuit 4 to turn on the instruction; when the audio signal is a low-frequency signal of the sleep-aid music, the user does not send an instruction, and the selection switch circuit 4 is closed.
Referring to fig. 2 IN conjunction with fig. 12, the audio power amplifier circuit 1 may be an LM386M power amplifier, the LM386M power amplifier is configured with a first pin IN +, a second pin OUT, and a third pin AV, and the first pin IN + is electrically connected to the signal receiving circuit 2 to receive the audio signal sent by the signal receiving circuit 2; the second pin OUT is electrically connected with the audio output circuit 3 to transmit the audio signal processed by the audio power amplifying circuit 1 to the audio output circuit 3; the third pin AV is electrically connected to the selection switch circuit 4.
Further, referring to fig. 3 in conjunction with fig. 12, the selection switch circuit 4 may be an SGM3157 analog switch, the SGM3157 analog switch has a first pin B1 and a second pin a, the low frequency feedback circuit 5 is connected between the second pin OUT of the audio power amplifier circuit 1 and the first pin B1 of the selection switch circuit 4, and the third pin AV of the audio power amplifier circuit 1 is connected to the second pin a of the selection switch circuit 4. The SGM3157 analog switch is used for controlling the on-off of an audio signal passing through the SGM3157 analog switch, further, the on-off of the audio signal passing through the SGM3157 analog switch is controlled by a switching mode of an MOS (metal oxide semiconductor) tube, and by utilizing the on-off characteristic of the MOS tube, the SGM3157 analog switch can realize Gao Guanduan impedance, and can make the on-resistance lower, so that the on-off and isolation of the audio signal passing through the SGM3157 analog switch can be realized.
Referring to fig. 1, 3 to 4, the sgm3157 analog switch further has a third pin VCC, and the low frequency enhancement circuit further includes a power supply circuit 6, where the power supply circuit 6 includes a fourth resistor R22, an eighth capacitor C39 and a zener diode D4; a fifth pin VDD of the audio power amplifying circuit 1 is connected to a third pin VCC of the selection switch circuit 4 through a fourth resistor R22, and the fourth resistor R22 serves as a current-limiting resistor, which can limit a current signal transmitted to the selection switch circuit 4 by the audio power amplifying circuit 1, and prevent an excessive current from damaging the selection switch circuit 4; the larger the resistance value of the fourth resistor R22 is, the more obvious the current limiting effect is; the smaller the resistance of the fourth resistor R22, the weaker the current limiting effect. The resistance value of the fourth resistor R22 is not limited in the present application, and may be set according to actual requirements.
The fifth pin VDD of the audio power amplifier circuit 1 is connected to the cathode of the zener diode D4 through the fourth resistor R22, and the anode of the zener diode D4 is grounded. The zener diode D4 utilizes the PN junction reverse breakdown state, the current through the zener diode D4 can vary over a wide range while the voltage across the zener diode D4 is substantially constant. Further, the resistance of the voltage stabilizing diode D4 is small when the voltage stabilizing diode D4 is conducted, and normal work of the voltage stabilizing diode D4 can be guaranteed through the current limiting effect of the fourth resistor R22; if the current is not limited by the fourth resistor R22, the current passing through the zener diode D4 exceeds the rated working current of the zener diode D4, which causes damage to the zener diode D4, and meanwhile, the higher current passing through the zener diode D4 causes an increase in the heat generated by the zener diode D4, which causes a rise in the temperature of the PN junction in the zener diode D4, and the temperature of the PN junction of the diode is in negative correlation with the on-resistance of the diode; the higher the temperature is, the smaller the resistance is, and the lower the temperature is, the larger the resistance is; with the rising of the temperature of the PN junction, the resistance value of the on-resistance of the diode is reduced, the current passing through the diode is increased, and the temperature of the PN junction is further increased until the voltage stabilizing diode D4 is burnt out. The eighth capacitor C39 can store electric energy and stably output the electric energy, so that the voltage stabilizing effect of the zener diode D4 is stable and smooth, and further, the voltage of the cathode of the zener diode D4 is prevented from being too high when the power is turned on, thereby avoiding the damage to the zener diode D4.
It should be noted that the low frequency enhancement circuit further includes a main control chip (not shown in the figure), and the main control chip is connected to the audio power amplification circuit 1 through the SGM3157 analog switch, so as to control the conversion process of the SGM3157 analog switch and the audio power amplification circuit 1. Meanwhile, the low-frequency enhancement circuit further comprises a key, and the key is electrically connected with the main control chip, so that the key can control the audio signal output by the power amplification circuit, for example: the modes of the previous song, the next song, the sound +, the sound-pause and the like can be switched through the keys, and the convenience of controlling the output audio signal can be further improved.
Further, referring to fig. 5, the low frequency feedback circuit 5 includes a first capacitor C3 and a first resistor R8 connected in series with the first capacitor C3, and the second pin OUT of the audio power amplifying circuit 1 is connected to the first pin B1 of the selection switch circuit 4 through the first capacitor C3 and the first resistor R8. The low-frequency feedback circuit 5 can feed back the audio signal output by the power amplifying circuit to the pre-amplifying circuit; the low-frequency feedback circuit 5 feeds the output audio signal back to the pre-amplification circuit in time, so that the audio signal output by the power amplification circuit can be enhanced in time, and when the audio signal received by the low-frequency feedback circuit 5 is a common audio signal (the common audio signal comprises a low-frequency signal and a high-frequency signal), the pre-amplification circuit can amplify the amplitude of the low-frequency-band audio signal with the frequency of 50HZ-150HZ in the common audio signal so as to enhance the low-frequency-band audio signal in the common audio signal.
Further, the feedback action of the low frequency feedback circuit 5 can increase the output gain of the audio power amplifier circuit 1, thereby reducing the nonlinear distortion of the audio power amplifier circuit 1, widening the frequency band of the audio power amplifier circuit 1, reducing the noise of the audio power amplifier circuit 1, and stabilizing the operating state of the audio power amplifier circuit 1. Meanwhile, the audio signals are transmitted in the form of electric signals, and the larger the resistance value of the first resistor R8 is, the fewer the fed audio signals are; the smaller the resistance of the same first resistor R8 is, the more the audio signal is fed back, and further, in order to transmit the audio signal output by the power amplification circuit to the power amplification circuit through the low frequency feedback circuit 5 relatively completely, the smaller the resistance of the first resistor R8 is required to feed back the more audio signal. The resistance value of the first resistor (R8) is not limited in the application and can be set according to actual requirements.
Further, referring to fig. 6 to 7, the audio output circuit 3 includes a second capacitor C20 and an output port CN1, and the output port CN1 is electrically connected to the second capacitor C20. The output port CN1 includes a first pin D1 and a second pin D2, the first pin D1 of the output port CN1 is connected to a second pin OUT of the audio power amplifier circuit 1 through a second capacitor C20, the second pin D2 is grounded, and the first pin D1 and the second pin D2 are further used for being connected to a load. It should be noted that the output port CN1 may be an output socket, and the output socket is used for connecting an external audio device to make a load sound or generate vibration. It should be noted that the second capacitor C20 is an output coupling capacitor, and the coupling capacitor couples and isolates the strong current system and the weak current system through the capacitor, so as to provide a high-frequency signal path, prevent the low-frequency current from entering the weak current system, and ensure personal safety; meanwhile, the high-frequency signal can provide energy for the loudspeaker or the bone conduction vibrator to drive the loudspeaker to make sound, and the bone conduction vibrator generates vibration. The second capacitor C20 is an output coupling capacitor, and functions as two: firstly, alternating current can pass through, direct current cannot pass through, and direct current signals are cut off, so that a loudspeaker coil and a vibrating diaphragm of a vibrator are prevented from being damaged by large direct current signals; secondly, coupling isolation is performed, alternating current signals are coupled, the second capacitor C20 and the load form a high-pass filter, the capacitance value of the second capacitor C20 is reduced, and the amplitude and the width of noise energy impact can be reduced. The output port CN1 further includes two buffer/latch units PAD, both of which are grounded and can be used for buffering or buffering part of the audio signal.
Referring to fig. 8 in conjunction with fig. 12, further, the signal receiving circuit 2 includes a third capacitor C15, a fourth capacitor C29 and a second resistor R9; the third capacitor C15 includes a first terminal AVINL and a second terminal, the first terminal AVINL of the third capacitor C15 is used for connecting with an external audio device to couple with an analog signal input by the external audio device; the second end of the third capacitor C15 has three paths, and the first path of the second end of the third capacitor C15 is connected with the first pin (IN +) of the audio power amplifying circuit 1; further, analog signals input by external audio equipment can be connected to the audio power amplification circuit 1 through a third capacitor C15, the third capacitor C15 is a coupling capacitor, alternating current signals input by the external audio equipment can be transmitted to the audio power amplification circuit 1 through the third capacitor C15 by utilizing the alternating current and direct current passing characteristic of the third capacitor C15, and accordingly static working points of front and rear two stages of circuits located on the third capacitor C15 can not affect each other; the third capacitor C15 can pass through an alternating current signal, the frequency of an input analog signal is high, the coupling capacitor has large capacity, and the analog signal input by an external audio device can be transmitted to the audio power amplifying circuit 1 under the condition of small attenuation.
The second path of the second end of the third capacitor C15 is grounded through the fourth capacitor C29, the fourth capacitor C29 can modulate alternating current signals, and the capacity of a filter capacitor can be increased in a rectifying part. The capacitor has the functions of passing high frequency and blocking low frequency, and by utilizing the filtering function of the capacitor, particularly, when the capacity of the third capacitor C15 is larger, low-frequency electric signals can be filtered; when the capacity of the third capacitor C15 is smaller, high-frequency signals can be filtered; while the voltage across the third capacitor C15 remains constant, the higher the signal frequency the greater the signal attenuation. When the external audio equipment is modulated and the input alternating current signals are connected, the input alternating current signals can be filtered through the fourth capacitor, and then interference of interference signals on the audio signals is avoided.
A third path of the second end of the third capacitor C15 is grounded through a second resistor R9, so that the first pin IN + of the audio power amplifying circuit 1 is IN a low level state, and noise IN the analog signal is further reduced; an audio signal input by external audio equipment is transmitted to the audio power amplifying circuit 1 through the second resistor R9, so that the voltage generated at the moment of starting up is prevented from influencing the input of the audio power amplifying circuit 1, and meanwhile, the attenuation degree of the voltage depends on the resistance value of the resistor.
Further, referring to fig. 9 in conjunction with fig. 12, the low frequency enhancement circuit further includes a fifth capacitor C5, the audio power amplifier circuit 1 further has a fourth pin DET, and the fourth pin DET of the audio power amplifier circuit 1 is grounded through the fifth capacitor C5 to filter noise generated during transmission of the audio signal and prevent the audio power amplifier circuit 1 from generating self-payment; the fourth pin DET is grounded through a fifth capacitor C5, so that the noise is filtered; the output of the audio power amplifying circuit 1 is stable, and the voltage value at the fourth pin DET can be half of the power supply voltage; the capacitance value of the fifth capacitor C5 is increased, so that the rising and falling speeds of the direct current reference voltage can be slowed down, and further, the noise can be effectively suppressed.
Further, referring to fig. 10 in conjunction with fig. 12, the low frequency enhancement circuit further includes a sixth capacitor C6, the audio power amplification circuit 1 further has a fifth pin VDD, and the fifth pin VDD of the audio power amplification circuit 1 is grounded through the sixth capacitor C6, so as to store energy at the moment when the audio power amplification circuit 1 is powered on, and transmit the stored energy to the audio output circuit 3. Specifically, the sixth capacitor C6 may serve as an energy storage capacitor for storing input electric energy and releasing stored electric energy. The sixth capacitor C6 for energy storage may collect charge through a rectifier and deliver the stored energy to the output of the power supply through the converter leads.
Further, referring to fig. 11 to 12, the low frequency enhancement circuit further includes a seventh capacitor C2 and a third resistor R4, the second pin OUT of the audio power amplifier circuit 1 is further grounded through the seventh capacitor C2 and the third resistor R4, so as to soften the sound emitted by the load, and block the ac voltage output by the audio power amplifier circuit 1, thereby avoiding damage to the speaker and/or the bone conduction vibrator connected to the audio output circuit 3; meanwhile, the seventh capacitor C2 can be used for filtering, and the larger the accommodating capacity of the seventh capacitor C2 is, the smaller the impedance is, so that the high-frequency signal can pass through, and the high-frequency signal can be filtered.
In a second aspect, the present application provides an audio playing device, where the audio playing device includes a low-frequency enhancing circuit, and the audio playing device can directly play audio signals with a frequency in a low frequency band of 50HZ to 150HZ, so as to facilitate sleep, and meanwhile, the low-frequency enhancing circuit can also be used to enhance the audio signals in the low frequency band of the common audio signals, so as to enable the enhanced low-frequency signals to help a user to go to sleep.
The same or similar reference numerals in the drawings of the present embodiment correspond to the same or similar components; in the description of the present application, it is to be understood that if there is an orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", etc. based on the orientation or positional relationship shown in the drawings, it is only for convenience of description and simplification of description, but it is not intended to indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and therefore, the terms describing the positional relationship in the drawings are only for illustrative purposes and are not to be construed as limitations of the present patent, and specific meanings of the above terms may be understood by those skilled in the art according to specific situations.
The present invention is not intended to be limited to the particular embodiments shown and described, but is to be accorded the widest scope consistent with the principles and novel features herein disclosed.
Claims (12)
1. A low frequency boost circuit, characterized in that said low frequency boost circuit comprises:
the signal receiving circuit is used for receiving an audio signal sent by external audio equipment;
the audio power amplifying circuit is connected with the signal receiving circuit and used for receiving the audio signal sent by the signal receiving circuit and carrying out power amplification;
the low-frequency feedback circuit is connected with the audio power amplifying circuit and is used for feeding the audio signal output by the audio power amplifying circuit back to the audio power amplifying circuit so as to enable the audio power amplifying circuit to perform power amplification on the low-frequency signal in the audio signal, wherein the frequency of the low-frequency signal is greater than or equal to 50Hz and less than or equal to 150Hz;
and the audio output circuit is connected with the audio power amplifying circuit and is used for outputting the audio signal amplified by the audio power amplifying circuit.
2. The low frequency boost circuit of claim 1, further comprising:
the low-frequency feedback circuit is connected with the audio power amplifying circuit through the selective switch circuit; when the audio signal is an audio signal of common music, the selection switch circuit is switched on, so that the low-frequency feedback circuit feeds back the low-frequency signal to the audio power amplification circuit through the selection switch circuit; when the audio signal is the audio signal of the sleep-aid music, the selection switch circuit is closed.
3. The low frequency enhancement circuit of claim 2, wherein the selection switch circuit is turned on or off according to a type of the received audio signal, or wherein the selection switch circuit is turned on or off according to a user-triggered instruction.
4. The low frequency boost circuit of claim 2, characterized IN that said audio power amplification circuit has a first pin (IN +) for receiving an audio signal, a second pin (OUT) for outputting an audio signal and a third pin (AV) for connection with said selection switch circuit;
a first pin (IN +) of the audio power amplifying circuit is connected with the signal receiving circuit;
the second pin (OUT) of the audio power amplifying circuit is connected with the audio output circuit so as to transmit the processed audio signal to the audio output circuit.
5. The low frequency boost circuit according to claim 4, wherein said selection switch circuit has a first pin (B1) and a second pin (A), said low frequency feedback circuit being connected between the second pin (OUT) of said audio power amplification circuit and the first pin (B1) of said selection switch circuit, and a third pin (AV) of said audio power amplification circuit being connected to the second pin (A) of said selection switch circuit.
6. Low frequency boost circuit according to claim 5, characterized in that said low frequency feedback circuit comprises a first capacitor (C3) and a first resistor (R8) in series with said first capacitor (C3), the second pin (OUT) of said audio power amplification circuit being connected to the first pin (B1) of said selection switch circuit through said first capacitor (C3) and said first resistor (R8).
7. The low frequency boost circuit according to claim 4, characterized in that said audio output circuit comprises a second capacitance (C20) and an output port (CN 1) connected to said second capacitance (C20);
the output port (CN 1) comprises a first pin (D1) and a second pin (D2), the first pin (D1) of the output port is connected with a second pin (OUT) of the audio power amplifying circuit through the second capacitor (C20), the second pin (D2) is grounded, and the first pin (D1) and the second pin (D2) are further used for being connected with an external loudspeaker and/or an external bone conduction vibrator.
8. The low frequency boost circuit of claim 4, wherein said signal receiving circuit comprises a third capacitor (C15), a fourth capacitor (C29) and a second resistor (R9);
the third capacitor (C15) comprises a first end and a second end, and the first end of the third capacitor (C15) is used for being connected with an external audio device so as to be coupled with an analog signal input by the external audio device;
the second end of the third capacitor (C15) is provided with three paths, and the first path of the second end of the third capacitor (C15) is connected with the first pin (IN +) of the audio power amplifying circuit;
a second path of the second end of the third capacitor (C15) is grounded through the fourth capacitor (C29);
the third path of the second end of the third capacitor (C15) is grounded through the second resistor (R9), so that the first pin (IN +) of the audio power amplifying circuit is IN a low level state, and the noise IN the analog signal is reduced.
9. The low frequency enhancement circuit according to claim 4, further comprising a fifth capacitor (C5), wherein the audio power amplification circuit further has a fourth pin (DET), and wherein the fourth pin (DET) of the audio power amplification circuit is grounded through the fifth capacitor (C5) to filter noise generated during transmission of the audio signal.
10. The low frequency boost circuit of claim 4, further comprising a sixth capacitor (C6), wherein said audio power amplifier circuit further has a fifth pin (VDD), and wherein said fifth pin (VDD) of said audio power amplifier circuit is grounded via said sixth capacitor (C6) to store energy at the instant of power-on of said audio power amplifier circuit and to deliver the stored energy to an audio output circuit.
11. The low frequency enhancement circuit according to claim 4, further comprising a seventh capacitor (C2) and a third resistor (R4), wherein the second pin (OUT) of the audio power amplifier circuit is further grounded via the seventh capacitor (C2) and the third resistor (R4) to block the AC voltage outputted by the audio power amplifier circuit, thereby preventing damage to a speaker and/or a bone conduction vibrator connected to the audio output circuit.
12. An audio playback apparatus, comprising:
a low frequency enhancement circuit as claimed in any one of claims 1 to 11.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202221438633.7U CN217770035U (en) | 2022-06-09 | 2022-06-09 | Low-frequency enhancement circuit and audio playing device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202221438633.7U CN217770035U (en) | 2022-06-09 | 2022-06-09 | Low-frequency enhancement circuit and audio playing device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN217770035U true CN217770035U (en) | 2022-11-08 |
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ID=83892800
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202221438633.7U Active CN217770035U (en) | 2022-06-09 | 2022-06-09 | Low-frequency enhancement circuit and audio playing device |
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| Country | Link |
|---|---|
| CN (1) | CN217770035U (en) |
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2022
- 2022-06-09 CN CN202221438633.7U patent/CN217770035U/en active Active
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