CN203120140U - Audio amplification circuit with standby function - Google Patents
Audio amplification circuit with standby function Download PDFInfo
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- CN203120140U CN203120140U CN 201320042169 CN201320042169U CN203120140U CN 203120140 U CN203120140 U CN 203120140U CN 201320042169 CN201320042169 CN 201320042169 CN 201320042169 U CN201320042169 U CN 201320042169U CN 203120140 U CN203120140 U CN 203120140U
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Abstract
An audio amplification circuit with a standby function comprises a primary amplification circuit, a reference voltage generating circuit, an audio power amplifying circuit and an intelligent switch circuit. The reference voltage generating circuit is provided with a first operational amplifier, wherein the first operational amplifier forms a follower and provides reference voltage; the primary amplifying circuit is provided with a second operational amplifier, wherein the second operational amplifier forms an inverse proportion amplifying circuit and performs primary magnification on audio input signals; the audio power amplifying circuit is provided with a third operational amplifier, wherein the third operational amplifier forms an inverse proportion amplifying circuit and performs power amplification on primary signals outputted by the primary amplifying circuit and is connected with a loudspeaker; the audio power amplifying circuit is further provided with a fourth operational amplifier, wherein the fourth operational amplifier forms an inverting circuit and performs inversion on signals outputted by the third operational amplifier and is connected with the loudspeaker; the intelligent switch circuit is provided with a fifth operational amplifier, wherein the fifth operational amplifier forms a comparison circuit and triggers a time-delay circuit formed by a sixth operational amplifier when the primary signals outputted by the primary amplifying circuit exceed a certain magnitude, and opens a signal input channel of the audio power amplifying circuit.
Description
Technical field
The utility model relates to a kind of audio amplifier circuit with idle function to be put, and belongs to the electron controls technology field.
Background technology
Carry out the front end of speech play at loud speaker, need one will faint audio signal to carry out that amplitude is amplified and the electronic equipment of power amplification, owing to during the influence of environment or transmission course effectively do not shield, can often sneak into noise in the audio signal.After these noises process amplitudes amplifications and audio frequency amplify, can from loud speaker, play back.If useful signal is very little even do not have in the audio signal, this time, noise will highlight, and gave the great discomfort of artificial one-tenth, and such as in places such as elevator cage, classroom, assembly halls, such harmful effect is unacceptable.
The utility model content
The purpose of this utility model is in order to overcome weak point of the prior art, a kind of audio amplifier circuit with idle function is provided, this device carries out amplitude to the audio signal of input and judges, have only when amplitude reaches certain size just can start audio power amplifying circuit, can effectively avoid The noise like this.
The technical scheme that its technical problem that solves the utility model adopts is:
A kind of audio amplifier circuit with idle function, comprise the audio signal of input is carried out the elementary amplifying circuit that amplitude is amplified, the reference voltage generating circuit of stable reference voltage is provided, to the audio power amplifying circuit that the output signal of described elementary amplifying circuit is carried out power amplification, can turn-off or open the intelligent switch circuit of described audio power amplifying circuit.Resistance R 5 is set described reference voltage generating circuit and 6 couples of power supply VCC of resistance R carry out dividing potential drop, and carry out filtering by capacitor C 3, connects the in-phase end of first operational amplifier again, and described first operational amplifier constitutes follower and output reference voltage V2.5;
The resistance R 1 that described elementary amplifying circuit setting is connected with audio input signal, the other end of described resistance R 1 connects resistance R 2, capacitor C 1 and capacitor C 2, the other end ground connection of described resistance R 2 and capacitor C 1, the other end of described capacitor C 2 connects resistance R 3, the other end of described resistance R 3 connects end of oppisite phase and the resistance R 4 of second operational amplifier, the in-phase end of described second operational amplifier connects reference voltage V2.5, the other end of described resistance R 4 connects the output of described second operational amplifier, and the output primary signal;
Described audio power amplifying circuit setting is connected capacitor C 4 with the output of described second operational amplifier, the other end of described capacitor C 4 connects resistance R 7, described resistance R 7 other ends connect capacitor C 5 and output switching signal, described capacitor C 5 other ends connect resistance R 8, the other end of described resistance R 8 connects end of oppisite phase and the resistance R 9 of the 3rd operational amplifier, the in-phase end of described the 3rd operational amplifier connects reference voltage V2.5, the other end of described resistance R 9 connects the output of described the 3rd operational amplifier, the output of described the 3rd operational amplifier connects positive pole and the resistance R 10 of loud speaker, the other end of described resistance R 10 connects end of oppisite phase and the resistance R 11 of four-operational amplifier, the in-phase end of described four-operational amplifier connects reference voltage V2.5, and the other end of described resistance R 11 connects the output of described four-operational amplifier and the negative pole of loud speaker;
The setting of described intelligent switch circuit is connected capacitor C 6 with the output of described second operational amplifier, the other end of described capacitor C 6 connects resistance R 14, the in-phase end of capacitor C 7 and the 5th operational amplifier, the other end ground connection of described resistance R 14 and capacitor C 7, the end of oppisite phase of described the 5th operational amplifier connects resistance R 12, resistance R 13 and capacitor C 8, the other end ground connection of described resistance R 12 and capacitor C 8, described resistance R 13 other ends connect power supply VCC, the output of described the 5th operational amplifier connects the base stage of triode Q1 by resistance R 15, the grounded emitter of described triode Q1, its collector electrode connects resistance R 16, the in-phase end of capacitor C 9 and the 6th operational amplifier, the other end of described resistance R 16 connects power supply VCC, the other end ground connection of described capacitor C 9, the end of oppisite phase of described the 6th operational amplifier connects reference voltage V2.5, output connects the base stage of triode Q2 by resistance R 18, the grounded emitter of described triode Q2, collector electrode connect the switching signal of resistance R 7 outputs of described audio power amplifying circuit.
The beneficial effects of the utility model mainly show: can carry out amplitude to the audio signal of input and judge, have only when amplitude reaches certain size and just can start audio power amplifying circuit, this device quits work and enters holding state under the situation that useful signal is close to zero, and can effectively avoid The noise like this.
Description of drawings
Fig. 1 is elementary amplifying circuit of the present utility model and reference voltage generating circuit theory diagram;
Fig. 2 is audio power amplifying circuit theory diagram of the present utility model;
Fig. 3 is intelligent switch schematic block circuit diagram of the present utility model.
Embodiment
Below in conjunction with accompanying drawing the utility model is further described:
With reference to Fig. 1-3, a kind of audio amplifier circuit with idle function, comprise the audio signal of input is carried out the elementary amplifying circuit that amplitude is amplified, the reference voltage generating circuit of stable reference voltage is provided, to the audio power amplifying circuit that the output signal of described elementary amplifying circuit is carried out power amplification, can turn-off or open the intelligent switch circuit of described audio power amplifying circuit.
Resistance R 5 is set described reference voltage generating circuit and 6 couples of power supply VCC of resistance R carry out dividing potential drop, and carry out filtering by capacitor C 3, connects the in-phase end of first operational amplifier again, and described first operational amplifier constitutes follower and output reference voltage V2.5.Described resistance R 5 and resistance R 6 are got similar resistance.Stable and the strong reference voltage of load capacity can be provided like this.
The resistance R 1 that described elementary amplifying circuit setting is connected with audio input signal, the other end of described resistance R 1 connects resistance R 2, capacitor C 1 and capacitor C 2, the other end ground connection of described resistance R 2 and capacitor C 1, the other end of described capacitor C 2 connects resistance R 3, the other end of described resistance R 3 connects end of oppisite phase and the resistance R 4 of second operational amplifier, the in-phase end of described second operational amplifier connects reference voltage V2.5, the other end of described resistance R 4 connects the output of described second operational amplifier, the output primary signal.Described second operational amplifier constitutes see-saw circuit, audio input signal is carried out amplitude amplify, and lays the foundation for follow-up power amplification and voltage ratio provide.
Described audio power amplifying circuit setting is connected capacitor C 4 with the output of described second operational amplifier, the other end of described capacitor C 4 connects resistance R 7, described resistance R 7 other ends connect capacitor C 5 and output switching signal, described capacitor C 5 other ends connect resistance R 8, the other end of described resistance R 8 connects end of oppisite phase and the resistance R 9 of the 3rd operational amplifier, the in-phase end of described the 3rd operational amplifier connects reference voltage V2.5, the other end of described resistance R 9 connects the output of described the 3rd operational amplifier, the output of described the 3rd operational amplifier connects positive pole and the resistance R 10 of loud speaker, the other end of described resistance R 10 connects end of oppisite phase and the resistance R 11 of four-operational amplifier, the in-phase end of described four-operational amplifier connects reference voltage V2.5, and the other end of described resistance R 11 connects the output of described four-operational amplifier and the negative pole of loud speaker.Described the 3rd operational amplifier constitutes see-saw circuit and carries out power amplification, and described four-operational amplifier formation amplification coefficient is 1 inverter, therefore constituting one group of opposite audio signal of phase place removes to drive described loud speaker, realizes effective power amplification.
The setting of described intelligent switch circuit is connected capacitor C 6 with the output of described second operational amplifier, the other end of described capacitor C 6 connects resistance R 14, the in-phase end of capacitor C 7 and the 5th operational amplifier, the other end ground connection of described resistance R 14 and capacitor C 7, the end of oppisite phase of described the 5th operational amplifier connects resistance R 12, resistance R 13 and capacitor C 8, the other end ground connection of described resistance R 12 and capacitor C 8, described resistance R 13 other ends connect power supply VCC, the output of described the 5th operational amplifier connects the base stage of triode Q1 by resistance R 15, the grounded emitter of described triode Q1, its collector electrode connects resistance R 16, the in-phase end of capacitor C 9 and the 6th operational amplifier, the other end of described resistance R 16 connects power supply VCC, the other end ground connection of described capacitor C 9, the end of oppisite phase of described the 6th operational amplifier connects reference voltage V2.5, output connects the base stage of triode Q2 by resistance R 18, the grounded emitter of described triode Q2, collector electrode connect the switching signal of resistance R 7 outputs of described audio power amplifying circuit.In the time of described triode Q2 conducting, be zero with the voltage clamp between described resistance R 7 and the capacitor C 5, therefore follow-up circuit does not have the signal input, and described loud speaker quits work, and enters holding state.
Described the 5th operational amplifier has constituted a comparator, comparative voltage is determined by described resistance R 12 and resistance R 13, when elementary signal surpasses described comparative voltage, described the 5th operational amplifier output high level, thereby described capacitor C 9 discharge, described the 6th operational amplifier output low levels are then given in described triode Q1 conducting, described triode Q2 state is converted to by state, and described resistance R 7 and capacitor C 5 allow signal to pass through.
In sum, this utility model can be carried out amplitude to the audio signal of input and be judged, have only when amplitude reaches certain size and just can start audio power amplifying circuit, this device quits work and enters holding state under the situation that useful signal is close to zero, and can effectively avoid The noise like this.
Claims (1)
1. audio amplifier circuit with idle function, comprise the audio signal of input is carried out the elementary amplifying circuit that amplitude is amplified, the reference voltage generating circuit of stable reference voltage is provided, the output signal of described elementary amplifying circuit is carried out the audio power amplifying circuit of power amplification, can turn-off or open the intelligent switch circuit of described audio power amplifying circuit, it is characterized in that: resistance R 5 is set described reference voltage generating circuit and 6 couples of power supply VCC of resistance R carry out dividing potential drop, and carry out filtering by capacitor C 3, the in-phase end that connects first operational amplifier again, described first operational amplifier constitutes follower and output reference voltage V2.5;
The resistance R 1 that described elementary amplifying circuit setting is connected with audio input signal, the other end of described resistance R 1 connects resistance R 2, capacitor C 1 and capacitor C 2, the other end ground connection of described resistance R 2 and capacitor C 1, the other end of described capacitor C 2 connects resistance R 3, the other end of described resistance R 3 connects end of oppisite phase and the resistance R 4 of second operational amplifier, the in-phase end of described second operational amplifier connects reference voltage V2.5, the other end of described resistance R 4 connects the output of described second operational amplifier, and the output primary signal;
Described audio power amplifying circuit setting is connected capacitor C 4 with the output of described second operational amplifier, the other end of described capacitor C 4 connects resistance R 7, described resistance R 7 other ends connect capacitor C 5 and output switching signal, described capacitor C 5 other ends connect resistance R 8, the other end of described resistance R 8 connects end of oppisite phase and the resistance R 9 of the 3rd operational amplifier, the in-phase end of described the 3rd operational amplifier connects reference voltage V2.5, the other end of described resistance R 9 connects the output of described the 3rd operational amplifier, the output of described the 3rd operational amplifier connects positive pole and the resistance R 10 of loud speaker, the other end of described resistance R 10 connects end of oppisite phase and the resistance R 11 of four-operational amplifier, the in-phase end of described four-operational amplifier connects reference voltage V2.5, and the other end of described resistance R 11 connects the output of described four-operational amplifier and the negative pole of loud speaker;
The setting of described intelligent switch circuit is connected capacitor C 6 with the output of described second operational amplifier, the other end of described capacitor C 6 connects resistance R 14, the in-phase end of capacitor C 7 and the 5th operational amplifier, the other end ground connection of described resistance R 14 and capacitor C 7, the end of oppisite phase of described the 5th operational amplifier connects resistance R 12, resistance R 13 and capacitor C 8, the other end ground connection of described resistance R 12 and capacitor C 8, described resistance R 13 other ends connect power supply VCC, the output of described the 5th operational amplifier connects the base stage of triode Q1 by resistance R 15, the grounded emitter of described triode Q1, its collector electrode connects resistance R 16, the in-phase end of capacitor C 9 and the 6th operational amplifier, the other end of described resistance R 16 connects power supply VCC, the other end ground connection of described capacitor C 9, the end of oppisite phase of described the 6th operational amplifier connects reference voltage V2.5, output connects the base stage of triode Q2 by resistance R 18, the grounded emitter of described triode Q2, collector electrode connect the switching signal of resistance R 7 outputs of described audio power amplifying circuit.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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CN 201320042169 CN203120140U (en) | 2013-01-27 | 2013-01-27 | Audio amplification circuit with standby function |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
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CN 201320042169 CN203120140U (en) | 2013-01-27 | 2013-01-27 | Audio amplification circuit with standby function |
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CN203120140U true CN203120140U (en) | 2013-08-07 |
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CN 201320042169 Expired - Fee Related CN203120140U (en) | 2013-01-27 | 2013-01-27 | Audio amplification circuit with standby function |
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Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN110311639A (en) * | 2019-06-27 | 2019-10-08 | 深圳和而泰智能控制股份有限公司 | A kind of sound detection circuit, voice recognition circuit and electronic equipment |
CN112036870A (en) * | 2020-08-27 | 2020-12-04 | 武汉奇致激光技术股份有限公司 | Non-contact IC card for playing audio and control method |
-
2013
- 2013-01-27 CN CN 201320042169 patent/CN203120140U/en not_active Expired - Fee Related
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN110311639A (en) * | 2019-06-27 | 2019-10-08 | 深圳和而泰智能控制股份有限公司 | A kind of sound detection circuit, voice recognition circuit and electronic equipment |
CN112036870A (en) * | 2020-08-27 | 2020-12-04 | 武汉奇致激光技术股份有限公司 | Non-contact IC card for playing audio and control method |
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Legal Events
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C14 | Grant of patent or utility model | ||
GR01 | Patent grant | ||
C17 | Cessation of patent right | ||
CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20130807 Termination date: 20140127 |