CN203942638U - Audio input circuit - Google Patents
Audio input circuit Download PDFInfo
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- CN203942638U CN203942638U CN201420288852.0U CN201420288852U CN203942638U CN 203942638 U CN203942638 U CN 203942638U CN 201420288852 U CN201420288852 U CN 201420288852U CN 203942638 U CN203942638 U CN 203942638U
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Abstract
The utility model discloses an audio input circuit, which comprises an analog switch circuit, an impedance conversion circuit and an earphone input circuit which are connected with the analog switch circuit, and a bias voltage circuit which is connected with the impedance conversion circuit; the analog switch circuit comprises an earphone interface, an earphone terminal CN18, an inductor L36, a switching control terminal SW, an audio signal terminal HP _ MIC0, a first input end HP _ MIC and a second input end HP _ MIC 1; when the earphone microphone interface is inserted into the electret microphone, the audio signal end HP _ MIC0 is connected with the first input end HP _ MIC; when the headset interface is inserted into a high impedance audio device, the audio signal terminal HP _ MIC0 and the second input terminal HP _ MIC1 are connected. Adopt the utility model discloses, can make the headset interface can support electret microphone and high resistant audio equipment simultaneously through analog switch circuit, expanded the compatibility of headset interface.
Description
Technical field
The utility model relates to electronic technology field, relates in particular to a kind of audio input circuit.
Background technology
Traditional computer earphone microphone interface is only supported headset style Electret condenser microphone, for call and low quality recording.And for equipment such as high-quality moving coil type microphone, electric guitar, electronic organs, because it has different output impedance separately, (as moving coil type microphone, output impedance is generally 200 Ω～600 Ω, the output impedance of electric guitar is 5k Ω～20k Ω, microphone output impedance is about 1k Ω, the output impedance of electronic organ is about 10k Ω), directly access earphone microphone interface, can cause serious distortion.And the principle of audio signal cascade is, rear class input impedance need be much larger than prime output impedance.Therefore, when design, need carry out impedance matching to the equipment of access.
In the prior art, in order to realize the support to high resistant audio frequency apparatus, on market, occur impedance inverter circuit to be arranged on the design in the adapter of customization.But impedance inverter circuit design, in adapter, need to be bought to corresponding adapter for different high resistant audio frequency apparatuses, and cost is higher and easily damage.And the fixedly design of impedance inverter circuit makes its poor compatibility.
Summary of the invention
Technical problem to be solved in the utility model is, a kind of audio input circuit is provided, and by analog switching circuit, makes earphone microphone interface can support Electret condenser microphone and high resistant audio frequency apparatus simultaneously, expanded the compatibility of earphone microphone interface.
For solving above technical problem, the utility model embodiment provides a kind of audio input circuit, comprise analog switching circuit, the impedance inverter circuit being connected with described analog switching circuit and headset input circuit, and the bias voltage circuit being connected with described impedance inverter circuit; Described analog switching circuit comprises earphone microphone interface, earphone terminal CN18, inductance L 36, switching controls end SW, audio signal end HP_MIC0, first input end HP_MIC and the second input HP_MIC1; Described earphone terminal CN18 comprises the first pin;
The first pin of described earphone terminal CN18 is connected with described earphone microphone interface, and one end of described inductance L 36 is connected with the first pin of described earphone terminal CN18, and the other end of described inductance L 36 is connected with described audio signal end HP_MIC0; Described first input end HP_MIC is connected with described headset input circuit; Described the second input HP_MIC1 is connected with described impedance inverter circuit;
When described earphone microphone interface inserts Electret condenser microphone, described switching controls end SW controls described audio signal end HP_MIC0 and is connected with described first input end HP_MIC;
When described earphone microphone interface inserts high resistant audio frequency apparatus, described switching controls end SW controls described audio signal end HP_MIC0 and is connected with described the second input HP_MIC1.
The audio input circuit that the utility model embodiment provides, can pass through analog switching circuit, makes earphone microphone interface can support Electret condenser microphone and high resistant audio frequency apparatus simultaneously, has expanded the compatibility of earphone microphone interface; Impedance inverter circuit is built in computer, makes computer can support different high resistant audio frequency apparatuses.
Accompanying drawing explanation
Fig. 1 is the structural representation of first embodiment in the audio input circuit that provides of the utility model;
Fig. 2 is the structural representation of second embodiment in the audio input circuit that provides of the utility model;
Fig. 3 is the structural representation of an embodiment of the impedance inverter circuit in the audio input circuit that provides of the utility model;
Fig. 4 is first's structural representation of the bias voltage circuit in the audio input circuit that provides of the utility model;
Fig. 5 is the second portion structural representation of the bias voltage circuit in the audio input circuit that provides of the utility model;
Fig. 6 is the structural representation of an embodiment of the headset input circuit in the audio input circuit that provides of the utility model.
Embodiment
Below in conjunction with the accompanying drawing in the utility model embodiment, the technical scheme in the utility model embodiment is clearly and completely described.
Referring to Fig. 1, it is the structural representation of first embodiment of the audio input circuit that provides of the utility model.
The present embodiment provides a kind of audio input circuit, comprises analog switching circuit 101, the impedance inverter circuit 102 being connected with analog switching circuit 101 and headset input circuit 104, and the bias voltage circuit 103 being connected with impedance inverter circuit 102.As shown in Figure 2, analog switching circuit 101 comprises earphone microphone interface, earphone terminal CN18, inductance L 36, switching controls end SW, audio signal end HP_MIC0, first input end HP_MIC and the second input HP_MIC1; Earphone terminal CN18 comprises the first pin;
The first pin of earphone terminal CN18 is connected with earphone microphone interface, and one end of inductance L 36 is connected with the first pin of earphone terminal CN18, and the other end of inductance L 36 is connected with audio signal end HP_MIC0; First input end HP_MIC is connected with headset input circuit 104; The second input HP_MIC1 is connected with impedance inverter circuit 102;
When earphone microphone interface inserts Electret condenser microphone, switching controls end SW controls audio signal end HP_MIC0 and is connected with first input end HP_MIC;
When earphone microphone interface inserts high resistant audio frequency apparatus, switching controls end SW controls audio signal end HP_MIC0 and is connected with the second input HP_MIC1.
Further, as shown in Figure 3, impedance inverter circuit 102 comprises the first capacitor C 55, the second capacitor C 54, the first resistance R 16, the second resistance R 18, operational amplifier U1, power supply VCC and the first output terminals A U_VINI_P;
One end of the first capacitor C 55 is connected with the second input HP_MIC1, and the other end of the first capacitor C 55 is connected with one end of the first resistance R 16, and the other end of the first resistance R 16 is connected with the inverting input of operational amplifier U1;
The in-phase input end of operational amplifier U1 is connected with bias voltage circuit 103, and the output of operational amplifier U1 is connected with one end of the second capacitor C 54, and the other end of the second capacitor C 54 connects the first output terminals A U_VINI_P; The positive power source terminal of operational amplifier U1 connects power supply VCC, the negative power end ground connection of operational amplifier U1;
One end of the second resistance R 18 is connected with the inverting input of operational amplifier U1, and the other end of the second resistance R 18 is connected with the output of operational amplifier U1.
It should be noted that, impedance inverter circuit 102 is reverse voltage followers.Wherein, the first capacitor C 55 and the second capacitor C 54 are the coupling capacitance that capacitance is at least 1uF.
Further, as shown in Figure 4 and Figure 5, bias voltage circuit 103 comprises power supply VBAT, the 3rd resistance R 85, the 4th resistance R 19, the 5th resistance R 60, the 6th resistance R 61, the 3rd capacitor C 138, the 4th capacitor C 134, the 5th capacitor C 74, the 6th capacitor C 95, field effect transistor Q7 and Enable Pin EN;
The source electrode of field effect transistor Q7 connects power supply VBAT, and the drain electrode of field effect transistor Q7 connects power supply VCC, and the grid of field effect transistor Q7 is connected with one end of the 4th resistance R 19, and the other end of the 4th resistance R 19 connects Enable Pin EN;
One end of the 3rd capacitor C 138 connects power supply VBAT, the other end ground connection of the 3rd capacitor C 138; One end of the 3rd resistance R 85 is connected with the source electrode of field effect transistor Q7, and the other end of the 3rd resistance R 85 is connected with the grid of field effect transistor Q7;
One end of the 4th capacitor C 134 connects power supply VCC, the other end ground connection of the 4th capacitor C 134;
One end of the 5th resistance R 60 connects power supply VCC, and the other end of the 5th resistance R 60 is connected with the in-phase input end of operational amplifier U1, the 5th capacitor C 74 and the 5th resistance R 60 parallel connections; One end of the 6th resistance R 61 is connected with the in-phase input end of operational amplifier U1, the other end ground connection of the 6th resistance R 61, the 6th capacitor C 95 and the 6th resistance R 61 parallel connections.
Further, as shown in Figure 6, headset input circuit 104 comprises the 7th capacitor C 129, the 8th capacitor C 137, the 9th capacitor C 133, the tenth capacitor C the 131, the 11 capacitor C the 135, the 12 capacitor C 130, the 7th resistance R 79, the 8th resistance R 81, power supply MICBIAS1 and the second output terminals A U_VINI_N;
One end of the 7th resistance R 79 connects power supply MICBIAS1, and the other end of the 7th resistance R 79 the respectively with seven capacitor C 129, the 9th capacitor C 133, the tenth capacitor C the 131, the 12 capacitor C 130 are connected with one end of the 8th resistance R 81;
The other end of the 7th capacitor C 129 is connected with the second output terminals A U_VINI_N, the other end of the 9th capacitor C 133 is connected with first input end HP_MIC, the tenth capacitor C 131 other end ground connection, the other end of the 8th resistance R 81 is connected with first input end HP_MIC, the other end ground connection of the 12 capacitor C 130;
One end ground connection of the 9th capacitor C 133, the other end of the 9th capacitor C 133 is connected with first input end HP_MIC; One end of the 8th capacitor C 137 is connected with first input end HP_MIC, and the other end of the 8th capacitor C 137 connects the first output terminals A U_VINI_P.
It should be noted that, power supply MICBIAS1 is that the audio signal of Electret condenser microphone output improves bias supply.In order to guarantee the normal transmission of audio signal, the 7th capacitor C 129 and the 8th capacitor C 137 are the coupling capacitance that capacitance is 0.1uF.And the 9th capacitor C 133, the tenth capacitor C 131 and the 11 capacitor C 135 are capacitance, be pF level electric capacity, for the High-frequency Interference of filtering audio signal.The 12 capacitor C 130 adopts the electric capacity of large capacitance, for exchanging ground connection.
Preferably, the first resistance R 16 and the second resistance R 18 are the resistance that resistance is 500k Ω.In order to support various high resistant audio frequency apparatuses, more than the input impedance of impedance inverter circuit at least should reach 500k Ω, therefore, the resistance of the first resistance R 16 and the second resistance R 18 is set to respectively to 500k Ω.
The operation principle of the audio input circuit below the utility model being provided is elaborated.
When earphone microphone interface inserts Electret condenser microphone, switching controls end SW controls audio signal end HP_MIC0 and is connected with first input end HP_MIC, power supply MICBIAS1 powers on, the audio signal of exporting for Electret condenser microphone provides bias supply, makes audio signal from the first output terminals A U_VINI_P and the second output terminals A U_VINI_N output.And Enable Pin EN is drawn high in bias voltage circuit 103, field effect transistor Q7 is operated in cut-off state, reduces circuit power consumption.
When earphone microphone interface inserts high resistant audio frequency apparatus, switching controls end SW controls audio signal end HP_MIC0 and is connected with the second input HP_MIC1, in bias voltage circuit 103, Enable Pin EN is dragged down, effect pipe Q7 is operated in conducting state, power supply VBAT powers to power supply VCC, the audio signal of exporting to high resistant audio frequency apparatus in impedance inverter circuit 102 by the in-phase input end of operational amplifier U1 provides bias supply, makes audio signal output to audio processing chip from the first output terminals A U_VINI_P and processes.
The above is preferred implementation of the present utility model; it should be pointed out that for those skilled in the art, do not departing under the prerequisite of the utility model principle; can also make some improvements and modifications, these improvements and modifications are also considered as protection range of the present utility model.
Claims (5)
1. an audio input circuit, is characterized in that, comprises analog switching circuit, the impedance inverter circuit being connected with described analog switching circuit and headset input circuit, and the bias voltage circuit being connected with described impedance inverter circuit; Described analog switching circuit comprises earphone microphone interface, earphone terminal CN18, inductance L 36, switching controls end SW, audio signal end HP_MIC0, first input end HP_MIC and the second input HP_MIC1; Described earphone terminal CN18 comprises the first pin;
The first pin of described earphone terminal CN18 is connected with described earphone microphone interface, and one end of described inductance L 36 is connected with the first pin of described earphone terminal CN18, and the other end of described inductance L 36 is connected with described audio signal end HP_MIC0; Described first input end HP_MIC is connected with described headset input circuit; Described the second input HP_MIC1 is connected with described impedance inverter circuit;
When described earphone microphone interface inserts Electret condenser microphone, described switching controls end SW controls described audio signal end HP_MIC0 and is connected with described first input end HP_MIC;
When described earphone microphone interface inserts high resistant audio frequency apparatus, described switching controls end SW controls described audio signal end HP_MIC0 and is connected with described the second input HP_MIC1.
2. audio input circuit as claimed in claim 1, is characterized in that, described impedance inverter circuit comprises the first capacitor C 55, the second capacitor C 54, the first resistance R 16, the second resistance R 18, operational amplifier U1, power supply VCC and the first output terminals A U_VINI_P;
One end of described the first capacitor C 55 is connected with described the second input HP_MIC1, and the other end of described the first capacitor C 55 is connected with one end of described the first resistance R 16, and the other end of described the first resistance R 16 is connected with the inverting input of described operational amplifier U1;
The in-phase input end of described operational amplifier U1 is connected with described bias voltage circuit, and the output of described operational amplifier U1 is connected with one end of described the second capacitor C 54, and the other end of described the second capacitor C 54 connects the first output terminals A U_VINI_P; The positive power source terminal of described operational amplifier U1 connects power supply VCC, the negative power end ground connection of described operational amplifier U1;
One end of described the second resistance R 18 is connected with the inverting input of described operational amplifier U1, and the other end of described the second resistance R 18 is connected with the output of described operational amplifier U1.
3. audio input circuit as claimed in claim 2, it is characterized in that, described bias voltage circuit comprises power supply VBAT, the 3rd resistance R 85, the 4th resistance R 19, the 5th resistance R 60, the 6th resistance R 61, the 3rd capacitor C 138, the 4th capacitor C 134, the 5th capacitor C 74, the 6th capacitor C 95, field effect transistor Q7 and Enable Pin EN;
The source electrode of described field effect transistor Q7 connects described power supply VBAT, and the drain electrode of described field effect transistor Q7 connects power supply VCC, and the grid of described field effect transistor Q7 is connected with one end of described the 4th resistance R 19, and the other end of described the 4th resistance R 19 connects Enable Pin EN;
One end of described the 3rd capacitor C 138 connects described power supply VBAT, the other end ground connection of described the 3rd capacitor C 138; Described the 3rd one end of resistance R 85 and the source electrode of described field effect transistor Q7 are connected, and described the 3rd other end of resistance R 85 and the grid of described field effect transistor Q7 are connected;
One end of described the 4th capacitor C 134 connects power supply VCC, the other end ground connection of described the 4th capacitor C 134;
One end of described the 5th resistance R 60 connects power supply VCC, and the other end of described the 5th resistance R 60 is connected with the in-phase input end of described operational amplifier U1, described the 5th capacitor C 74 and described the 5th resistance R 60 parallel connections; One end of described the 6th resistance R 61 is connected with the in-phase input end of described operational amplifier U1, the other end ground connection of described the 6th resistance R 61, described the 6th capacitor C 95 and described the 6th resistance R 61 parallel connections.
4. audio input circuit as claimed in claim 1, it is characterized in that, described headset input circuit comprises the 7th capacitor C 129, the 8th capacitor C 137, the 9th capacitor C 133, the tenth capacitor C the 131, the 11 capacitor C the 135, the 12 capacitor C 130, the 7th resistance R 79, the 8th resistance R 81, power supply MICBIAS1 and the second output terminals A U_VINI_N;
One end of described the 7th resistance R 79 connects power supply MICBIAS1, the other end of described the 7th resistance R 79 is connected with one end of described the 8th resistance R 81 with described the 7th capacitor C 129, described the 9th capacitor C 133, described the tenth capacitor C 131, described the 12 capacitor C 130 respectively;
The other end of described the 7th capacitor C 129 is connected with described the second output terminals A U_VINI_N, the other end of described the 9th capacitor C 133 is connected with described first input end HP_MIC, described the tenth capacitor C 131 other end ground connection, the other end of described the 8th resistance R 81 is connected with described first input end HP_MIC, the other end ground connection of described the 12 capacitor C 130;
One end ground connection of described the 9th capacitor C 133, the other end of described the 9th capacitor C 133 is connected with described first input end HP_MIC; One end of described the 8th capacitor C 137 is connected with described first input end HP_MIC, and the other end of described the 8th capacitor C 137 connects described the first output terminals A U_VINI_P.
5. audio input circuit as claimed in claim 2, is characterized in that, described the first resistance R 16 and described the second resistance R 18 are the resistance that resistance is 500 k Ω.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420288852.0U CN203942638U (en) | 2014-05-30 | 2014-05-30 | Audio input circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420288852.0U CN203942638U (en) | 2014-05-30 | 2014-05-30 | Audio input circuit |
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| CN203942638U true CN203942638U (en) | 2014-11-12 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201420288852.0U Expired - Lifetime CN203942638U (en) | 2014-05-30 | 2014-05-30 | Audio input circuit |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2016095597A1 (en) * | 2014-12-16 | 2016-06-23 | 中兴通讯股份有限公司 | Impedance matching method and apparatus for electret microphone, and communication device |
| CN109889953A (en) * | 2019-03-08 | 2019-06-14 | 李志飞 | Sound equipment and its audio signal and microphone signal input control circuit |
-
2014
- 2014-05-30 CN CN201420288852.0U patent/CN203942638U/en not_active Expired - Lifetime
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2016095597A1 (en) * | 2014-12-16 | 2016-06-23 | 中兴通讯股份有限公司 | Impedance matching method and apparatus for electret microphone, and communication device |
| US10284949B2 (en) | 2014-12-16 | 2019-05-07 | Zte Corporation | Impedance matching method and apparatus for electret microphone, and communication device |
| CN109889953A (en) * | 2019-03-08 | 2019-06-14 | 李志飞 | Sound equipment and its audio signal and microphone signal input control circuit |
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Legal Events
| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C41 | Transfer of patent application or patent right or utility model | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20151229 Address after: Ke Xue Cheng Guang Bao Lu, Guangzhou high tech Development Zone in Guangdong province 510663 No. 192 4 floor Patentee after: Guangzhou Shiyuan Electronic Technology Company Limited Patentee after: GUANGZHOU RUIXIN ELECTRONICS Co.,Ltd. Address before: Ke Xue Cheng Guang Bao Lu, Guangzhou high tech Development Zone in Guangdong province 510663 No. 192 4 floor Patentee before: Guangzhou Shiyuan Electronic Technology Company Limited |
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| TR01 | Transfer of patent right | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20200507 Address after: 510530 Guangdong city of Guangzhou province YUNPU Whampoa district four Road No. 6 Patentee after: Guangzhou Shiyuan Electronic Technology Company Limited Address before: Ke Xue Cheng Guang Bao Lu, Guangzhou high tech Development Zone in Guangdong province 510663 No. 192 4 floor Co-patentee before: GUANGZHOU RUIXIN ELECTRONICS Co.,Ltd. Patentee before: Guangzhou Shiyuan Electronic Technology Company Limited |
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| CX01 | Expiry of patent term | ||
| CX01 | Expiry of patent term |
Granted publication date: 20141112 |