CN105047212A - Audio play circuit and player - Google Patents
Audio play circuit and player Download PDFInfo
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- CN105047212A CN105047212A CN201510447067.4A CN201510447067A CN105047212A CN 105047212 A CN105047212 A CN 105047212A CN 201510447067 A CN201510447067 A CN 201510447067A CN 105047212 A CN105047212 A CN 105047212A
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- audio
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- audio playing
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Abstract
The invention discloses an audio play circuit, comprising a power supply module, an audio conversion module and an isolation module, wherein the input end of the power supply module is connected with the power supply end of an external device; the output end of the power supply module is connected with the voltage input end of the audio conversion module; the signal input end of the audio conversion module is used for receiving input of an audio signal; the signal output end of the audio conversion module is used for outputting a converted audio signal to the audio signal input end of the external device; the grounding end of the power supply module serves as the system grounding end of the audio play circuit; the grounding end of the audio conversion module serves as the audio grounding end of the audio play circuit; and an isolation module is connected between the system grounding end of the audio play circuit and the audio grounding end of the audio play circuit. The invention further discloses a player. According to the audio play circuit and the player, the isolation module is adopted for isolating the system grounding end of the player from the audio grounding end, and power supply current noise does not interfere the audio grounding end, so that the interference of the current noise on the audio signal is effectively avoided.
Description
Technical field
The present invention relates to audio frequency play-back technology field, particularly audio playing circuit and player.
Background technology
In portable media player, usually can be provided with USB power source input interface and audio output interface.When player is connected with power amplifying device, connects the USB power source input interface of player and the power output interface of power amplifying device by USB line, realize power amplifying device and power to the system power supply circuit of player; And connecting the audio output interface of player and the audio input interface of power amplifying device by tone frequency channel wire, the audio frequency realizing player plays exports sound by power amplifying device.In player circuit, the earth terminal of system power supply circuit and the earth terminal of voicefrequency circuit link together, while sound signal is exported to power amplifying device by tone frequency channel wire by player, power amplifying device is also powered to player, supply current noise can be superimposed upon in sound signal, causes in audio frequency playing process and produces larger interference noise.
Summary of the invention
Fundamental purpose of the present invention is for providing a kind of audio playing circuit and player, and in effective minimizing player, supply current noise is to the interference of sound signal.
The present invention proposes a kind of audio playing circuit, be connected to an external unit, comprise power module, audio conversion module and isolation module, the input end of described power module connects the feeder ear of described external unit, and the output terminal of described power module connects the voltage input end of described audio conversion module; The input of the signal input part received audio signal of described audio conversion module, the signal output part of described audio conversion module exports the audio signal input end of the sound signal after changing to described external unit; The earth terminal of described power module is as the system earth end of described audio playing circuit, the earth terminal of described audio conversion module, as the audio frequency earth terminal of described audio playing circuit, is connected described isolation module between the system earth end of described audio playing circuit and the audio frequency earth terminal of described audio playing circuit.
Preferably, described isolation module comprises the first resistance, and described first resistance is connected between the system earth end of described audio playing circuit and the audio frequency earth terminal of described audio playing circuit.
Preferably, multiple electric capacity in parallel is also connected with between the system earth end of described audio playing circuit and the audio frequency earth terminal of described audio playing circuit.
Preferably, described audio playing circuit also comprises filtration module, described audio conversion module comprises voltage regulation unit and D/A conversion unit, the input end of described filtration module connects the output terminal of described power module, the output terminal of described filtration module connects the voltage input end of described voltage regulation unit, the earth terminal of described filtration module connects the earth terminal of described voltage regulation unit, the voltage output end of described voltage regulation unit connects the voltage input end of described D/A conversion unit, described voltage regulation unit is all connected the audio frequency earth terminal of described audio playing circuit with the earth terminal of D/A conversion unit.
Preferably, described filtration module comprises the second resistance and the first electric capacity, described voltage regulation unit comprises low pressure difference linear voltage regulator, described second resistance is connected between the voltage input end of described low pressure difference linear voltage regulator and the output terminal of described power module, be connected described first electric capacity between the voltage input end of described low pressure difference linear voltage regulator and the earth terminal of described low pressure difference linear voltage regulator, the earth terminal of described low pressure difference linear voltage regulator connects the audio frequency earth terminal of described audio playing circuit.
Preferably, the Enable Pin of described low pressure difference linear voltage regulator is through the input of the 3rd resistance receiving key control signal, the voltage output end of described low pressure difference linear voltage regulator connects the voltage input end of described D/A conversion unit, and the voltage output end of described low pressure difference linear voltage regulator also connects the audio frequency earth terminal of described audio playing circuit through the second electric capacity.
Preferably, the resistance R1 ∈ [1 Ω, 100 Ω] of described first resistance.
Preferably, the resistance R1=10 Ω of described first resistance.
The present invention also proposes a kind of player, be connected with external unit, comprise audio playing circuit, described audio playing circuit connects described external unit, comprise power module, audio conversion module and isolation module, the input end of described power module connects the feeder ear of external unit, and the output terminal of described power module connects the voltage input end of described audio conversion module; The input of the signal input part received audio signal of described audio conversion module, the signal output part of described audio conversion module exports the audio signal input end of the sound signal after changing to described external unit; The earth terminal of described power module is as the system earth end of described audio playing circuit, the earth terminal of described audio conversion module, as the audio frequency earth terminal of described audio playing circuit, is connected described isolation module between the system earth end of described audio playing circuit and the audio frequency earth terminal of described audio playing circuit.
Preferably, the signal output part of described audio conversion module is connected through tone frequency channel wire with between the audio signal input end of described external unit, be connected through USB line between the input end of described power module and the feeder ear of described external unit, the audio frequency earth terminal of described audio playing circuit connects the audio frequency earth terminal of described external unit through the ground wire of described tone frequency channel wire, and the system earth end of described audio playing circuit connects the system earth end of described external unit through the ground wire of described USB line.
The present invention adopts isolation module the system earth end of audio playing circuit and audio frequency earth terminal to be isolated, audio frequency earth terminal no longer affects by system earth end, the supply current noise of EVAC (Evacuation Network Computer Model) earth terminal can not be crosstalked on audio frequency earth terminal, and then the sound signal of player output can not be affected, effectively prevent the interference of current noise to sound signal.
Accompanying drawing explanation
Fig. 1 is the schematic diagram that in the embodiment of the present invention, player is connected with external unit;
Fig. 2 is the module diagram of the first embodiment of sound intermediate frequency playing circuit of the present invention;
Fig. 3 is the circuit diagram of the first embodiment that in the first embodiment of sound intermediate frequency playing circuit of the present invention, isolation module is connected with system earth end and audio frequency earth terminal;
Fig. 4 be embodiment illustrated in fig. 3 in equivalent electrical circuit;
Fig. 5 is the circuit diagram of the second embodiment that in the first embodiment of sound intermediate frequency playing circuit of the present invention, isolation module is connected with system earth end and audio frequency earth terminal;
Fig. 6 is the module diagram of the second embodiment of audio playing circuit of the present invention;
Fig. 7 is the circuit diagram that in the second embodiment of audio playing circuit of the present invention, filtration module is connected with voltage regulation unit.
The realization of the object of the invention, functional characteristics and advantage will in conjunction with the embodiments, are described further with reference to accompanying drawing.
Embodiment
Should be appreciated that specific embodiment described herein only in order to explain the present invention, be not intended to limit the present invention.
Reference Fig. 1, Fig. 1 are the schematic diagram that in the embodiment of the present invention, player is connected with external unit.Player 100 in the present embodiment is connected with external unit 200, and external unit 200 can be voice frequency power amplification equipment.Player 100 comprises USB power source input interface and sound signal output interface, and external unit 200 comprises USB feeder ear and audio signal input end.The USB power source input interface of player 100 connects the USB feeder ear of external unit 200 through USB line, powered to player 100 by external unit 200.The sound signal output interface of player 100 connects the audio signal input end of external unit 200 through tone frequency channel wire, by player 100, the sound signal play is exported to external unit 200 and carry out outer putting.Respective ground wire is all included in USB line and tone frequency channel wire, the audio frequency earth terminal of player 100 connects the audio frequency earth terminal of external unit 200 through the ground wire of tone frequency channel wire, and the system earth end of player 100 connects the system earth end of external unit 200 through the ground wire of USB line.The player 100 of the present embodiment includes audio playing circuit 101, and concrete structure and the principle of work of this audio playing circuit 101 elaborate in subsequent embodiment.
With reference to the module diagram that Fig. 2, Fig. 2 are the first embodiment of sound intermediate frequency playing circuit of the present invention.The audio playing circuit 101 that the present embodiment is mentioned, be connected with external unit 200, comprise power module 110, audio conversion module 120 and isolation module 130, the input end of power module 110 connects the feeder ear of external unit 200, and the output terminal of power module 110 connects the voltage input end of audio conversion module 120; The input of the signal input part received audio signal of audio conversion module 120, the signal output part of audio conversion module 120 exports the audio signal input end of the sound signal after changing to external unit 200; The earth terminal of power module 110 is as the system earth end of audio playing circuit 101, the earth terminal of audio conversion module 120, as the audio frequency earth terminal of audio playing circuit 101, is connected isolation module 130 between the system earth end of audio playing circuit 101 and the audio frequency earth terminal of audio playing circuit 101.
Because external unit 200 is powered to player 100, supply current noise can impact the system earth end of player 100, be crosstalked into the audio frequency earth terminal of player 100 in order to avoid supply current noise from the system earth end of player 100, and then be added in the sound signal of audio conversion module 120 output, the present embodiment employing connects isolation module 130 and is isolated by the earth terminal of the earth terminal of power module 110 and audio conversion module 120, the audio frequency earth terminal of audio playing circuit 101 no longer affects by the system earth end of audio playing circuit 101, the supply current noise of EVAC (Evacuation Network Computer Model) earth terminal can not be crosstalked on audio frequency earth terminal, and then the sound signal of audio conversion module 120 output can not be affected, effectively prevent the interference of current noise to sound signal.
Further, be the circuit diagram of the first embodiment that in the first embodiment of sound intermediate frequency playing circuit of the present invention, isolation module is connected with system earth end and audio frequency earth terminal with reference to figure 3 and Fig. 4, Fig. 3, Fig. 4 be embodiment illustrated in fig. 3 in equivalent electrical circuit.In figure 3, isolation module 130 comprises the first resistance R1, and the first resistance R1 is connected between the system earth end of audio playing circuit 101 and the audio frequency earth terminal of audio playing circuit 101.System earth end due to audio playing circuit 101 is connected on the ground wire of USB line, the ground wire of USB line exists line resistance R
uSB ground wire, so in player 100 course of work, supply current is carried in the ground wire two ends of USB line, forms a voltage noise U
uSB noise.Equally, also there is a line resistance R in the ground wire of tone frequency channel wire
audio frequency ground wire, so, supply current is carried in the voltage noise U at the ground wire two ends of tone frequency channel wire
audio-frequency noise=U
uSB noise* R
audio frequency ground wire/ (R1+R
audio frequency ground wire).From this formula, when R1 equals 0 ohm, U
audio-frequency noise=U
uSB noise; Work as R1>>R
audio frequency ground wiretime, U
audio-frequency noise<<U
uSB noise.Supplying in electronic Noise Suppression, R1 resistance is larger, and power supply noise suppression effect is better.But, owing to R1 also existing the working current that audio conversion module 120 provides, if R1 resistance is too large, the logic input of audio conversion module 120 can be affected.Therefore, the resistance of R1 can be limited in the scope of R1 ∈ [1 Ω, 100 Ω], can U be made
audio-frequency noiseeffectively reduced.In addition, the resistance value R on the ground wire of tone frequency channel wire is considered
audio frequency ground wireusually at 0.1 ohms, the resistance R1=10 Ω of the first resistance R1 can be made, make the voltage noise U at the ground wire two ends of tone frequency channel wire
audio-frequency noisereduce by tens times, effectively improve the impact of supply current noise on sound signal.
Further, with reference to figure 5, Fig. 5 be sound intermediate frequency playing circuit of the present invention the first embodiment in the circuit diagram of the second embodiment that is connected with system earth end and audio frequency earth terminal of isolation module.Multiple electric capacity in parallel is also connected with between the system earth end of audio playing circuit 101 and the audio frequency earth terminal of audio playing circuit 101, as have employed two electric capacity Ca and Cb in Fig. 5, be connected in parallel between the system earth end of audio playing circuit 101 and audio frequency earth terminal.Adopt the supply current on Capacitor apart system earth end to be loaded into audio frequency earth terminal, further obviate the impact of supply current noise on sound signal.
With reference to the module diagram that Fig. 6, Fig. 6 are the second embodiment of audio playing circuit of the present invention.The present embodiment is on basis embodiment illustrated in fig. 2, add filtration module 140, audio conversion module 120 comprises voltage regulation unit 121 and D/A conversion unit 122, the input end of filtration module 140 connects the output terminal of power module 110, the output terminal of filtration module 140 connects the voltage input end of voltage regulation unit 121, the earth terminal of filtration module 140 connects the earth terminal of voltage regulation unit 121, the voltage output end of voltage regulation unit 121 connects the voltage input end of D/A conversion unit 122, voltage regulation unit 121 is all connected the audio frequency earth terminal of audio playing circuit 101 with the earth terminal of D/A conversion unit 122.The filtration module 140 of the present embodiment can design according to frequency range residing for current noise, the signal of frequency range residing for filtering current noise, is conducive to reducing supply current noise to the interference of audio frequency earth terminal.
Further, reference Fig. 7, Fig. 7 is the circuit diagram that in the second embodiment of audio playing circuit of the present invention, filtration module is connected with voltage regulation unit.Voltage regulation unit 121 in the present embodiment comprises low pressure difference linear voltage regulator LDO, in order to reduce the reference noise of low pressure difference linear voltage regulator LDO, filtration module 140 have employed low-pass filter, comprise the second resistance R2 and the first electric capacity C1, the second resistance R2 is connected between the voltage input end VIN of low pressure difference linear voltage regulator LDO and the output terminal of power module 110, the first electric capacity C1 is connected between the voltage input end VIN of low pressure difference linear voltage regulator LDO and the earth terminal GND of low pressure difference linear voltage regulator LDO, the earth terminal GND of low pressure difference linear voltage regulator LDO connects the audio frequency earth terminal of audio playing circuit 101.Further, the Enable Pin EN of low pressure difference linear voltage regulator LDO is through the input of the 3rd resistance R3 receiving key control signal, the voltage output end VOUT of low pressure difference linear voltage regulator LDO connects the voltage input end of D/A conversion unit 122, and the voltage output end VOUT of low pressure difference linear voltage regulator LDO also connects the audio frequency earth terminal of audio playing circuit 101 through the second electric capacity C2.The present embodiment forms low-pass filter by the second resistance R2 and the first electric capacity C1, HFS in the voltage signal that filter out power module exports, the simultaneously also filtering noise of HFS, make the voltage signal that is input in LDO more stable, be conducive to the reference noise reducing LDO, further obviate the impact of supply current noise on sound signal.
The foregoing is only the preferred embodiments of the present invention; not thereby the scope of the claims of the present invention is limited; every utilize instructions of the present invention and accompanying drawing content to do equivalent structure or equivalent flow process conversion; or be directly or indirectly used in other relevant technical fields, be all in like manner included in scope of patent protection of the present invention.
Claims (10)
1. an audio playing circuit, be connected to an external unit, it is characterized in that, comprise power module, audio conversion module and isolation module, the input end of described power module connects the feeder ear of described external unit, and the output terminal of described power module connects the voltage input end of described audio conversion module; The input of the signal input part received audio signal of described audio conversion module, the signal output part of described audio conversion module exports the audio signal input end of the sound signal after changing to described external unit; The earth terminal of described power module is as the system earth end of described audio playing circuit, the earth terminal of described audio conversion module, as the audio frequency earth terminal of described audio playing circuit, is connected described isolation module between the system earth end of described audio playing circuit and the audio frequency earth terminal of described audio playing circuit.
2. audio playing circuit as claimed in claim 1, it is characterized in that, described isolation module comprises the first resistance, and described first resistance is connected between the system earth end of described audio playing circuit and the audio frequency earth terminal of described audio playing circuit.
3. audio playing circuit as claimed in claim 2, is characterized in that, be also connected with multiple electric capacity in parallel between the system earth end of described audio playing circuit and the audio frequency earth terminal of described audio playing circuit.
4. audio playing circuit as claimed in claim 1 or 2, it is characterized in that, described audio playing circuit also comprises filtration module, described audio conversion module comprises voltage regulation unit and D/A conversion unit, the input end of described filtration module connects the output terminal of described power module, the output terminal of described filtration module connects the voltage input end of described voltage regulation unit, the earth terminal of described filtration module connects the earth terminal of described voltage regulation unit, the voltage output end of described voltage regulation unit connects the voltage input end of described D/A conversion unit, described voltage regulation unit is all connected the audio frequency earth terminal of described audio playing circuit with the earth terminal of D/A conversion unit.
5. audio playing circuit as claimed in claim 4, it is characterized in that, described filtration module comprises the second resistance and the first electric capacity, described voltage regulation unit comprises low pressure difference linear voltage regulator, described second resistance is connected between the voltage input end of described low pressure difference linear voltage regulator and the output terminal of described power module, be connected described first electric capacity between the voltage input end of described low pressure difference linear voltage regulator and the earth terminal of described low pressure difference linear voltage regulator, the earth terminal of described low pressure difference linear voltage regulator connects the audio frequency earth terminal of described audio playing circuit.
6. audio playing circuit as claimed in claim 5, it is characterized in that, the Enable Pin of described low pressure difference linear voltage regulator is through the input of the 3rd resistance receiving key control signal, the voltage output end of described low pressure difference linear voltage regulator connects the voltage input end of described D/A conversion unit, and the voltage output end of described low pressure difference linear voltage regulator also connects the audio frequency earth terminal of described audio playing circuit through the second electric capacity.
7. audio playing circuit as claimed in claim 2, is characterized in that, the resistance R1 ∈ [1 Ω, 100 Ω] of described first resistance.
8. audio playing circuit as claimed in claim 2, is characterized in that, the resistance R1=10 Ω of described first resistance.
9. a player, is connected with external unit, it is characterized in that, comprises the audio playing circuit described in any one of claim 1 to 8.
10. player as claimed in claim 9, it is characterized in that, the signal output part of described audio conversion module is connected through tone frequency channel wire with between the audio signal input end of described external unit, be connected through USB line between the input end of described power module and the feeder ear of described external unit, the audio frequency earth terminal of described audio playing circuit connects the audio frequency earth terminal of described external unit through the ground wire of described tone frequency channel wire, and the system earth end of described audio playing circuit connects the system earth end of described external unit through the ground wire of described USB line.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510447067.4A CN105047212B (en) | 2015-07-27 | 2015-07-27 | Audio playing circuit and player |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510447067.4A CN105047212B (en) | 2015-07-27 | 2015-07-27 | Audio playing circuit and player |
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| Publication Number | Publication Date |
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| CN105047212A true CN105047212A (en) | 2015-11-11 |
| CN105047212B CN105047212B (en) | 2018-04-10 |
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| CN201510447067.4A Expired - Fee Related CN105047212B (en) | 2015-07-27 | 2015-07-27 | Audio playing circuit and player |
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| CN111130337A (en) * | 2019-12-03 | 2020-05-08 | 浪潮金融信息技术有限公司 | Audio isolation noise reduction scheme based on power isolation |
| CN114189257A (en) * | 2020-09-15 | 2022-03-15 | 瑞昱半导体股份有限公司 | Audio receiver and method for audio receiver |
| CN115150602A (en) * | 2022-08-31 | 2022-10-04 | 深圳市橙子数字科技有限公司 | High-fidelity DLP projector |
| CN117477952A (en) * | 2023-12-27 | 2024-01-30 | 吉林省龙电电气有限公司 | Power module with adjustable output based on multipath voltage |
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