CN205454077U - NOISE -CANCELLING HEADPHONES and audio input switching circuit thereof - Google Patents
NOISE -CANCELLING HEADPHONES and audio input switching circuit thereof Download PDFInfo
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- CN205454077U CN205454077U CN201521133628.5U CN201521133628U CN205454077U CN 205454077 U CN205454077 U CN 205454077U CN 201521133628 U CN201521133628 U CN 201521133628U CN 205454077 U CN205454077 U CN 205454077U
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Abstract
The utility model belongs to the technical field of the earphone, especially, relate to a NOISE -CANCELLING HEADPHONES and audio input switching circuit thereof. A NOISE -CANCELLING HEADPHONES's audio input switching circuit, connects the audio frequency to connect J1, fall make an uproar microphone MIC and loudspeaker B1 respectively, L channel or R channel that the audio frequency connects J1 connect all the way the input of audio input filtering coupling unit, the output termination of audio input filtering coupling unit BTL earphone power amplifier unit's input, BTL earphone power amplifier unit just, negative output end connects through resistance R9 and resistance R8 respectively loudspeaker B1 just, the negative pole, resistance R10 and electric capacity C2 establish ties between loudspeaker B1's the positive pole and ground, the input termination of noise reduction system unit the microphone MIC that makes an uproar falls. The embodiment of the utility model provides an in, this NOISE -CANCELLING HEADPHONES's audio input switching circuit adopts four switch tubes of discrete component to remove to replace mechanical switch and realizes that input audio signal switches the function, and this circuit structure not only simple structure is reliable to avoid using the noise of mechanical switch production or the phenomenon of spike noise.
Description
Technical field
This utility model belongs to ear phone technology field, particularly relates to a kind of noise cancelling headphone and audio frequency inputting switching circuit thereof.
Background technology
Noise cancelling headphone is owing to can stop outside noise, it is achieved good noise reduction, is widely used in the middle of daily life.
The input audio signal of existing noise cancelling headphone is leaded up to export after BTL earphone power amplifier module and is play to loudspeaker, and another road is directly output to loudspeaker and plays, and present noise cancelling headphone uses mechanical switch to realize input audio signal handoff functionality.But, use mechanical switch can bring the phenomenon such as switch noise or spike noise, so can have a strong impact on the result of broadcast of earphone.
Utility model content
The purpose of this utility model embodiment is to provide the audio frequency inputting switching circuit of a kind of noise cancelling headphone, it is intended to solves present noise cancelling headphone and uses mechanical switch can bring switch noise or the problem of spike noise.
This utility model embodiment is achieved in that the audio frequency inputting switching circuit of a kind of noise cancelling headphone, meets audio connector J1, noise reduction microphone MIC and loudspeaker B1 respectively, and the audio frequency inputting switching circuit of described noise cancelling headphone includes:
Noise reduction switch S1, the first switching tube, second switch pipe, the 3rd switching tube, the 4th switching tube, noise reduction system unit, audio frequency input filter coupling unit, BTL earphone power amplifier unit, resistance R1, resistance R2, resistance R3, resistance R4, resistance R5, resistance R6, resistance R7, resistance R8, resistance R9, resistance R10, electric capacity C1 and electric capacity C2；
nullThe L channel of described audio connector J1 or R channel one tunnel connect the input of described audio frequency input filter coupling unit，The output of described audio frequency input filter coupling unit terminates the input of described BTL earphone power amplifier unit，Described BTL earphone power amplifier unit is just、Negative output terminal is just meeting described loudspeaker B1 by resistance R9 and resistance R8 respectively、Negative pole，Described resistance R10 and electric capacity C2 is connected between positive pole and the ground of described loudspeaker B1，The input of described noise reduction system unit terminates described noise reduction microphone MIC，The output of described noise reduction system unit terminates the outfan of described audio frequency input filter coupling unit，The end that controls controlling end and BTL earphone power amplifier unit of described noise reduction system unit connects first end of described noise reduction switch S1 simultaneously，The second termination power VDD of described noise reduction switch S1，The L channel of described audio connector J1 or R channel separately lead up to series connection resistance R6、Resistance R1、Electric capacity C1 and resistance R7 connects the negative pole of described loudspeaker B1，The high potential of described first switching tube terminates described resistance R6 and the public connecting end of resistance R1，The cold end ground connection of described first switching tube，The high potential of described second switch pipe terminates described resistance R6 and the public connecting end of resistance R1，The cold end ground connection of described second switch pipe，The high potential of described 3rd switching tube terminates described resistance R1 and the public connecting end of electric capacity C1，The cold end ground connection of described 3rd switching tube，The high potential of described 4th switching tube terminates described resistance R1 and the public connecting end of electric capacity C1，The cold end ground connection of described 4th switching tube，Described first switching tube and second switch pipe connect first end of described noise reduction switch S1 respectively by resistance R4 and resistance R2，Described 3rd switching tube and the 4th switching tube connect first end of described noise reduction switch S1 respectively by resistance R5 and resistance R3.
In said structure, described first switching tube uses audion Q1, the hot end of the most described first switching tube of current collection of described audion Q1, the cold end of the most described first switching tube of transmitting of described audion Q1, the base stage of described audion Q1 is the control end of described first switching tube.
In said structure, described second switch pipe uses audion Q2, the hot end of the transmitting the most described second switch pipe of described audion Q2, the cold end of the current collection the most described second switch pipe of described audion Q2, the base stage of described audion Q2 is the control end of described second switch pipe.
In said structure, described 3rd switching tube uses audion Q3, the hot end of the most described 3rd switching tube of current collection of described audion Q3, the cold end of the most described 3rd switching tube of transmitting of described audion Q3, the base stage of described audion Q3 is the control end of described 3rd switching tube.
In said structure, described 4th switching tube uses audion Q4, the hot end of the most described 4th switching tube of transmitting of described audion Q4, the cold end of the most described 4th switching tube of current collection of described audion Q4, the base stage of described audion Q4 is the control end of described 4th switching tube.
The another object of this utility model embodiment is to provide a kind of noise cancelling headphone, audio frequency inputting switching circuit including noise cancelling headphone, the audio frequency inputting switching circuit of described noise cancelling headphone meets audio connector J1, noise reduction microphone MIC and loudspeaker B1 respectively, and the audio frequency inputting switching circuit of described noise cancelling headphone includes:
Noise reduction switch S1, the first switching tube, second switch pipe, the 3rd switching tube, the 4th switching tube, noise reduction system unit, audio frequency input filter coupling unit, BTL earphone power amplifier unit, resistance R1, resistance R2, resistance R3, resistance R4, resistance R5, resistance R6, resistance R7, resistance R8, resistance R9, resistance R10, electric capacity C1 and electric capacity C2；
nullThe L channel of described audio connector J1 or R channel one tunnel connect the input of described audio frequency input filter coupling unit，The output of described audio frequency input filter coupling unit terminates the input of described BTL earphone power amplifier unit，Described BTL earphone power amplifier unit is just、Negative output terminal is just meeting described loudspeaker B1 by resistance R9 and resistance R8 respectively、Negative pole，Described resistance R10 and electric capacity C2 is connected between positive pole and the ground of described loudspeaker B1，The input of described noise reduction system unit terminates described noise reduction microphone MIC，The output of described noise reduction system unit terminates the outfan of described audio frequency input filter coupling unit，The end that controls controlling end and BTL earphone power amplifier unit of described noise reduction system unit connects first end of described noise reduction switch S1 simultaneously，The second termination power VDD of described noise reduction switch S1，The L channel of described audio connector J1 or R channel separately lead up to series connection resistance R6、Resistance R1、Electric capacity C1 and resistance R7 connects the negative pole of described loudspeaker B1，The high potential of described first switching tube terminates described resistance R6 and the public connecting end of resistance R1，The cold end ground connection of described first switching tube，The high potential of described second switch pipe terminates described resistance R6 and the public connecting end of resistance R1，The cold end ground connection of described second switch pipe，The high potential of described 3rd switching tube terminates described resistance R1 and the public connecting end of electric capacity C1，The cold end ground connection of described 3rd switching tube，The high potential of described 4th switching tube terminates described resistance R1 and the public connecting end of electric capacity C1，The cold end ground connection of described 4th switching tube，Described first switching tube and second switch pipe connect first end of described noise reduction switch S1 respectively by resistance R4 and resistance R2，Described 3rd switching tube and the 4th switching tube connect first end of described noise reduction switch S1 respectively by resistance R5 and resistance R3.
In said structure, described first switching tube uses audion Q1, the hot end of the most described first switching tube of current collection of described audion Q1, the cold end of the most described first switching tube of transmitting of described audion Q1, the base stage of described audion Q1 is the control end of described first switching tube.
In said structure, described second switch pipe uses audion Q2, the hot end of the transmitting the most described second switch pipe of described audion Q2, the cold end of the current collection the most described second switch pipe of described audion Q2, the base stage of described audion Q2 is the control end of described second switch pipe.
In said structure, described 3rd switching tube uses audion Q3, the hot end of the most described 3rd switching tube of current collection of described audion Q3, the cold end of the most described 3rd switching tube of transmitting of described audion Q3, the base stage of described audion Q3 is the control end of described 3rd switching tube.
In said structure, described 4th switching tube uses audion Q4, the hot end of the most described 4th switching tube of transmitting of described audion Q4, the cold end of the most described 4th switching tube of current collection of described audion Q4, the base stage of described audion Q4 is the control end of described 4th switching tube.
In this utility model embodiment, the audio frequency inputting switching circuit of this noise cancelling headphone uses four switching tubes of discrete component to go to substitute mechanical switch to realize input audio signal handoff functionality, this circuit structure is not only simple in structure reliably, and avoids noise or the phenomenon of spike noise using mechanical switch to produce.
Accompanying drawing explanation
Fig. 1 is the circuit structure diagram of the audio frequency inputting switching circuit of the noise cancelling headphone that this utility model embodiment provides.
Detailed description of the invention
In order to make the purpose of this utility model, technical scheme and advantage clearer, below in conjunction with drawings and Examples, this utility model is further elaborated.Should be appreciated that specific embodiment described herein, only in order to explain this utility model, is not used to limit this utility model.
Fig. 1 shows the circuit structure of the audio frequency inputting switching circuit of the noise cancelling headphone that this utility model embodiment provides, and for convenience of description, illustrate only the part relevant to this utility model embodiment.
The audio frequency inputting switching circuit of a kind of noise cancelling headphone, meets audio connector J1, noise reduction microphone MIC and loudspeaker B1 respectively, and the audio frequency inputting switching circuit of described noise cancelling headphone includes:
Noise reduction switch S1, the first switching tube 1, second switch pipe the 2, the 3rd switching tube the 3, the 4th switching tube 4, noise reduction system unit 5, audio frequency input filter coupling unit 6, BTL earphone power amplifier unit 7, resistance R1, resistance R2, resistance R3, resistance R4, resistance R5, resistance R6, resistance R7, resistance R8, resistance R9, resistance R10, electric capacity C1 and electric capacity C2；
nullThe L channel of described audio connector J1 or R channel one tunnel connect the input of described audio frequency input filter coupling unit 6，The output of described audio frequency input filter coupling unit 6 terminates the input of described BTL earphone power amplifier unit 7，Described BTL earphone power amplifier unit 7 is just、Negative output terminal is just meeting described loudspeaker B1 by resistance R9 and resistance R8 respectively、Negative pole，Described resistance R10 and electric capacity C2 is connected between positive pole and the ground of described loudspeaker B1，The input of described noise reduction system unit 5 terminates described noise reduction microphone MIC，5 outputs of described noise reduction system unit terminate the outfan of described audio frequency input filter coupling unit 7，The end that controls controlling end and BTL earphone power amplifier unit 7 of described noise reduction system unit 5 connects first end of described noise reduction switch S1 simultaneously，The second termination power VDD of described noise reduction switch S1，The L channel of described audio connector J1 or R channel separately lead up to series connection resistance R6、Resistance R1、Electric capacity C1 and resistance R7 connects the negative pole of described loudspeaker B1，The high potential of described first switching tube 1 terminates described resistance R6 and the public connecting end of resistance R1，The cold end ground connection of described first switching tube 1，The high potential of described second switch pipe 2 terminates described resistance R6 and the public connecting end of resistance R1，The cold end ground connection of described second switch pipe 2，The high potential of described 3rd switching tube 3 terminates described resistance R1 and the public connecting end of electric capacity C1，The cold end ground connection of described 3rd switching tube 3，The high potential of described 4th switching tube 4 terminates described resistance R1 and the public connecting end of electric capacity C1，The cold end ground connection of described 4th switching tube 4，Described first switching tube 1 and second switch pipe 2 connect first end of described noise reduction switch S1 respectively by resistance R4 and resistance R2，Described 3rd switching tube 3 and the 4th switching tube 4 connect first end of described noise reduction switch S1 respectively by resistance R5 and resistance R3.
As this utility model one embodiment, described first switching tube 1 uses audion Q1, the hot end of the most described first switching tube 1 of current collection of described audion Q1, the cold end of the most described first switching tube 1 of transmitting of described audion Q1, the base stage of described audion Q1 is the control end of described first switching tube 1.
As this utility model one embodiment, described second switch pipe 2 uses audion Q2, the hot end of the transmitting the most described second switch pipe 2 of described audion Q2, the cold end of the current collection the most described second switch pipe 2 of described audion Q2, the base stage of described audion Q2 is the control end of described second switch pipe 2.
As this utility model one embodiment, described 3rd switching tube 3 uses audion Q3, the hot end of the most described 3rd switching tube 3 of current collection of described audion Q3, the cold end of the most described 3rd switching tube 3 of transmitting of described audion Q3, the base stage of described audion Q3 is the control end of described 3rd switching tube 3.
As this utility model one embodiment, described 4th switching tube 4 uses audion Q4, the hot end of the most described 4th switching tube 4 of transmitting of described audion Q4, the cold end of the most described 4th switching tube 4 of current collection of described audion Q4, the base stage of described audion Q4 is the control end of described 4th switching tube 4.
This utility model embodiment also provides for a kind of noise cancelling headphone, audio frequency inputting switching circuit including noise cancelling headphone, the audio frequency inputting switching circuit of described noise cancelling headphone meets audio connector J1, noise reduction microphone MIC and loudspeaker B1 respectively, and the audio frequency inputting switching circuit of described noise cancelling headphone includes:
Noise reduction switch S1, the first switching tube 1, second switch pipe the 2, the 3rd switching tube the 3, the 4th switching tube 4, noise reduction system unit 5, audio frequency input filter coupling unit 6, BTL earphone power amplifier unit 7, resistance R1, resistance R2, resistance R3, resistance R4, resistance R5, resistance R6, resistance R7, resistance R8, resistance R9, resistance R10, electric capacity C1 and electric capacity C2；
nullThe L channel of described audio connector J1 or R channel one tunnel connect the input of described audio frequency input filter coupling unit 6，The output of described audio frequency input filter coupling unit 6 terminates the input of described BTL earphone power amplifier unit 7，Described BTL earphone power amplifier unit 7 is just、Negative output terminal is just meeting described loudspeaker B1 by resistance R9 and resistance R8 respectively、Negative pole，Described resistance R10 and electric capacity C2 is connected between positive pole and the ground of described loudspeaker B1，The input of described noise reduction system unit 5 terminates described noise reduction microphone MIC，5 outputs of described noise reduction system unit terminate the outfan of described audio frequency input filter coupling unit 7，The end that controls controlling end and BTL earphone power amplifier unit 7 of described noise reduction system unit 5 connects first end of described noise reduction switch S1 simultaneously，The second termination power VDD of described noise reduction switch S1，The L channel of described audio connector J1 or R channel separately lead up to series connection resistance R6、Resistance R1、Electric capacity C1 and resistance R7 connects the negative pole of described loudspeaker B1，The high potential of described first switching tube 1 terminates described resistance R6 and the public connecting end of resistance R1，The cold end ground connection of described first switching tube 1，The high potential of described second switch pipe 2 terminates described resistance R6 and the public connecting end of resistance R1，The cold end ground connection of described second switch pipe 2，The high potential of described 3rd switching tube 3 terminates described resistance R1 and the public connecting end of electric capacity C1，The cold end ground connection of described 3rd switching tube 3，The high potential of described 4th switching tube 4 terminates described resistance R1 and the public connecting end of electric capacity C1，The cold end ground connection of described 4th switching tube 4，Described first switching tube 1 and second switch pipe 2 connect first end of described noise reduction switch S1 respectively by resistance R4 and resistance R2，Described 3rd switching tube 3 and the 4th switching tube 4 connect first end of described noise reduction switch S1 respectively by resistance R5 and resistance R3.
As this utility model one embodiment, described first switching tube 1 uses audion Q1, the hot end of the most described first switching tube 1 of current collection of described audion Q1, the cold end of the most described first switching tube 1 of transmitting of described audion Q1, the base stage of described audion Q1 is the control end of described first switching tube 1.
As this utility model one embodiment, described second switch pipe 2 uses audion Q2, the hot end of the transmitting the most described second switch pipe 2 of described audion Q2, the cold end of the current collection the most described second switch pipe 2 of described audion Q2, the base stage of described audion Q2 is the control end of described second switch pipe 2.
As this utility model one embodiment, described 3rd switching tube 3 uses audion Q3, the hot end of the most described 3rd switching tube 3 of current collection of described audion Q3, the cold end of the most described 3rd switching tube 3 of transmitting of described audion Q3, the base stage of described audion Q3 is the control end of described 3rd switching tube 3.
As this utility model one embodiment, described 4th switching tube 4 uses audion Q4, the hot end of the most described 4th switching tube 4 of transmitting of described audion Q4, the cold end of the most described 4th switching tube 4 of current collection of described audion Q4, the base stage of described audion Q4 is the control end of described 4th switching tube 4.
The operation principle of the audio frequency inputting switching circuit of this noise cancelling headphone is:
When noise reduction switch S1 opens, power vd D powers to noise reduction system unit 5 and BTL earphone power amplifier unit 7, and noise reduction system unit 5 and BTL earphone power amplifier unit 7 normally works.
Now when audio connector J1 inputs music, concert is divided into two-way, and audio frequency input filter coupling unit 6 of leading up to is input in BTL earphone power amplifier unit 7, promotes loudspeaker B1 playback music by BTL earphone power amplifier unit 7 after being amplified；nullAnother road is then entered in electrical switch handover network by resistance R6，Because noise reduction switch S1 opens，Power vd D passes through resistance R2、Resistance R3、Resistance R4、Resistance R5 puts audion Q1、Audion Q2、Audion Q3、The base stage of audion Q4 is high level，Four audions are in conducting state，The music signal come from resistance R6 is all by audion Q1、Audion Q2 be conducting to (GND)，Because of audion Q3、Audion Q4 is also switched on ground connection，Resistance R7 and electric capacity C1 is equivalent to a LC series filtering network and receives GND and be connected on BTL earphone power amplifier unit 7 and export the negative pole of loudspeaker B1，Resistance R10 and electric capacity C2 composition LC series network has been connected on BTL earphone power amplifier unit 7 and has exported the positive pole of loudspeaker B1，So loudspeaker B1 exports positive and negative signal shaping network balance.
When noise reduction switch S1 closes or battery VDD does not has electricity, noise reduction system unit 5 and BTL earphone power amplifier unit 7 is not powered and is not worked, and music signal can not promote loudspeaker B1 playback music signal by BTL earphone power amplifier unit 7.
Now four audions are made to be in high-impedance state because of audion Q1, audion Q2, audion Q3, the base stage dead electricity of audion Q4, CE electrode resistance is the biggest, the music signal come from resistance R6 can not flow to GND, directly it is input to loudspeaker B1 from resistance R1, electric capacity C1, resistance R7, GND is returned to again from resistance R10, electric capacity C2, so loudspeaker B1 playback music.
In this utility model embodiment, the audio frequency inputting switching circuit of this noise cancelling headphone uses four switching tubes of discrete component to go to substitute mechanical switch to realize input audio signal handoff functionality, this circuit structure is not only simple in structure reliably, and avoids noise or the phenomenon of spike noise using mechanical switch to produce.
The foregoing is only preferred embodiment of the present utility model, not in order to limit this utility model, all any amendment, equivalent and improvement etc. made within spirit of the present utility model and principle, within should be included in protection domain of the present utility model.
Claims (10)
1. an audio frequency inputting switching circuit for noise cancelling headphone, meets audio connector J1, noise reduction microphone MIC and loudspeaker B1, it is characterised in that the audio frequency inputting switching circuit of described noise cancelling headphone includes respectively:
Noise reduction switch S1, the first switching tube, second switch pipe, the 3rd switching tube, the 4th switching tube, noise reduction system unit, audio frequency input filter coupling unit, BTL earphone power amplifier unit, resistance R1, resistance R2, resistance R3, resistance R4, resistance R5, resistance R6, resistance R7, resistance R8, resistance R9, resistance R10, electric capacity C1 and electric capacity C2；
nullThe L channel of described audio connector J1 or R channel one tunnel connect the input of described audio frequency input filter coupling unit，The output of described audio frequency input filter coupling unit terminates the input of described BTL earphone power amplifier unit，Described BTL earphone power amplifier unit is just、Negative output terminal is just meeting described loudspeaker B1 by resistance R9 and resistance R8 respectively、Negative pole，Described resistance R10 and electric capacity C2 is connected between positive pole and the ground of described loudspeaker B1，The input of described noise reduction system unit terminates described noise reduction microphone MIC，The output of described noise reduction system unit terminates the outfan of described audio frequency input filter coupling unit，The end that controls controlling end and BTL earphone power amplifier unit of described noise reduction system unit connects first end of described noise reduction switch S1 simultaneously，The second termination power VDD of described noise reduction switch S1，The L channel of described audio connector J1 or R channel separately lead up to series connection resistance R6、Resistance R1、Electric capacity C1 and resistance R7 connects the negative pole of described loudspeaker B1，The high potential of described first switching tube terminates described resistance R6 and the public connecting end of resistance R1，The cold end ground connection of described first switching tube，The high potential of described second switch pipe terminates described resistance R6 and the public connecting end of resistance R1，The cold end ground connection of described second switch pipe，The high potential of described 3rd switching tube terminates described resistance R1 and the public connecting end of electric capacity C1，The cold end ground connection of described 3rd switching tube，The high potential of described 4th switching tube terminates described resistance R1 and the public connecting end of electric capacity C1，The cold end ground connection of described 4th switching tube，Described first switching tube and second switch pipe connect first end of described noise reduction switch S1 respectively by resistance R4 and resistance R2，Described 3rd switching tube and the 4th switching tube connect first end of described noise reduction switch S1 respectively by resistance R5 and resistance R3.
2. the audio frequency inputting switching circuit of noise cancelling headphone as claimed in claim 1, it is characterized in that, described first switching tube uses audion Q1, the hot end of the most described first switching tube of current collection of described audion Q1, the cold end of the most described first switching tube of transmitting of described audion Q1, the base stage of described audion Q1 is the control end of described first switching tube.
3. the audio frequency inputting switching circuit of noise cancelling headphone as claimed in claim 1, it is characterized in that, described second switch pipe uses audion Q2, the hot end of the transmitting the most described second switch pipe of described audion Q2, the cold end of the current collection the most described second switch pipe of described audion Q2, the base stage of described audion Q2 is the control end of described second switch pipe.
4. the audio frequency inputting switching circuit of noise cancelling headphone as claimed in claim 1, it is characterized in that, described 3rd switching tube uses audion Q3, the hot end of the most described 3rd switching tube of current collection of described audion Q3, the cold end of the most described 3rd switching tube of transmitting of described audion Q3, the base stage of described audion Q3 is the control end of described 3rd switching tube.
5. the audio frequency inputting switching circuit of noise cancelling headphone as claimed in claim 1, it is characterized in that, described 4th switching tube uses audion Q4, the hot end of the most described 4th switching tube of transmitting of described audion Q4, the cold end of the most described 4th switching tube of current collection of described audion Q4, the base stage of described audion Q4 is the control end of described 4th switching tube.
6. a noise cancelling headphone, audio frequency inputting switching circuit including noise cancelling headphone, the audio frequency inputting switching circuit of described noise cancelling headphone meets audio connector J1, noise reduction microphone MIC and loudspeaker B1 respectively, it is characterised in that the audio frequency inputting switching circuit of described noise cancelling headphone includes:
Noise reduction switch S1, the first switching tube, second switch pipe, the 3rd switching tube, the 4th switching tube, noise reduction system unit, audio frequency input filter coupling unit, BTL earphone power amplifier unit, resistance R1, resistance R2, resistance R3, resistance R4, resistance R5, resistance R6, resistance R7, resistance R8, resistance R9, resistance R10, electric capacity C1 and electric capacity C2；
nullThe L channel of described audio connector J1 or R channel one tunnel connect the input of described audio frequency input filter coupling unit，The output of described audio frequency input filter coupling unit terminates the input of described BTL earphone power amplifier unit，Described BTL earphone power amplifier unit is just、Negative output terminal is just meeting described loudspeaker B1 by resistance R9 and resistance R8 respectively、Negative pole，Described resistance R10 and electric capacity C2 is connected between positive pole and the ground of described loudspeaker B1，The input of described noise reduction system unit terminates described noise reduction microphone MIC，The output of described noise reduction system unit terminates the outfan of described audio frequency input filter coupling unit，The end that controls controlling end and BTL earphone power amplifier unit of described noise reduction system unit connects first end of described noise reduction switch S1 simultaneously，The second termination power VDD of described noise reduction switch S1，The L channel of described audio connector J1 or R channel separately lead up to series connection resistance R6、Resistance R1、Electric capacity C1 and resistance R7 connects the negative pole of described loudspeaker B1，The high potential of described first switching tube terminates described resistance R6 and the public connecting end of resistance R1，The cold end ground connection of described first switching tube，The high potential of described second switch pipe terminates described resistance R6 and the public connecting end of resistance R1，The cold end ground connection of described second switch pipe，The high potential of described 3rd switching tube terminates described resistance R1 and the public connecting end of electric capacity C1，The cold end ground connection of described 3rd switching tube，The high potential of described 4th switching tube terminates described resistance R1 and the public connecting end of electric capacity C1，The cold end ground connection of described 4th switching tube，Described first switching tube and second switch pipe connect first end of described noise reduction switch S1 respectively by resistance R4 and resistance R2，Described 3rd switching tube and the 4th switching tube connect first end of described noise reduction switch S1 respectively by resistance R5 and resistance R3.
7. noise cancelling headphone as claimed in claim 6, it is characterized in that, described first switching tube uses audion Q1, the hot end of the most described first switching tube of current collection of described audion Q1, the cold end of the most described first switching tube of transmitting of described audion Q1, the base stage of described audion Q1 is the control end of described first switching tube.
8. noise cancelling headphone as claimed in claim 6, it is characterized in that, described second switch pipe uses audion Q2, the hot end of the transmitting the most described second switch pipe of described audion Q2, the cold end of the current collection the most described second switch pipe of described audion Q2, the base stage of described audion Q2 is the control end of described second switch pipe.
9. noise cancelling headphone as claimed in claim 6, it is characterized in that, described 3rd switching tube uses audion Q3, the hot end of the most described 3rd switching tube of current collection of described audion Q3, the cold end of the most described 3rd switching tube of transmitting of described audion Q3, the base stage of described audion Q3 is the control end of described 3rd switching tube.
10. noise cancelling headphone as claimed in claim 6, it is characterized in that, described 4th switching tube uses audion Q4, the hot end of the most described 4th switching tube of transmitting of described audion Q4, the cold end of the most described 4th switching tube of current collection of described audion Q4, the base stage of described audion Q4 is the control end of described 4th switching tube.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN108632710A (en) * | 2018-05-11 | 2018-10-09 | 深圳市天微电子股份有限公司 | active noise reduction chip, device and method |
| CN112672252A (en) * | 2020-12-07 | 2021-04-16 | 阮兰敏 | Hearing aid circuit for medical bed |
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2015
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108632710A (en) * | 2018-05-11 | 2018-10-09 | 深圳市天微电子股份有限公司 | active noise reduction chip, device and method |
| CN112672252A (en) * | 2020-12-07 | 2021-04-16 | 阮兰敏 | Hearing aid circuit for medical bed |
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