CN201674469U - Audio-frequency power amplifier circuit with automatic gain control circuit - Google Patents
Audio-frequency power amplifier circuit with automatic gain control circuit Download PDFInfo
- Publication number
- CN201674469U CN201674469U CN2010201411380U CN201020141138U CN201674469U CN 201674469 U CN201674469 U CN 201674469U CN 2010201411380 U CN2010201411380 U CN 2010201411380U CN 201020141138 U CN201020141138 U CN 201020141138U CN 201674469 U CN201674469 U CN 201674469U
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- operational amplifier
- audio
- automatic gain
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Abstract
The utility model relates to an audio-frequency power amplifier circuit with an automatic gain control circuit, comprising a full-differential operational amplifier, wherein each of the same-phase input end and an inverse-phase input end of the amplifier is provided with a voltage-dividing resistor, and a feedback resistor is respectively arranged between the same-phase input end and an output end and between the inverse-phase input end and the output end; and a bias circuit is connected with the full-differential operational amplifier. The utility model is also provided with the automatic gain control circuit; the input end of the control circuit is connected with the output end of the full-differential operational amplifier; a reference voltage circuit is connected with the control circuit; and the output end of the control circuit is connected with an adjustable resistor on the input end of the full-differential operational amplifier. The audio-frequency power amplifier circuit compares an output signal with reference voltage to obtain a digital signal, and uses the digital signal to control a front resistance value at the input end of the amplifier, thus being capable of realizing that the fixed gain is maintained to amplify the audio-frequency signals when small signals are input, and guaranteeing that the output audio-frequency signals obtain high linearity and low harmonic distortion by reducing the closed-loop gain in the circuit when the large audio-frequency signals are input.
Description
[technical field]
The utility model relates to the audio-frequency power amplifier in the extensive analog integrated circuit design field, particularly a kind of audio-frequency power amplifier circuit that has automatic gain control.
[background technology]
Fig. 1 is the circuit structure of power audio amplifier traditional in a kind of prior art, and in the sort circuit structure, audio signal is amplified through the fully differential operational amplifier.The output of audio signal changes with the variation of input, when importing big audio signal (Vi+ and Vi-are bigger), after this audio input signal amplifies through the fully differential operational amplifier, output Vo-, Vo+ is also bigger, thereby causes the output peakedness ratio of audio signal bigger, again this signal is carried out modulation and demodulation, then the signal after the demodulation can produce the top distortion, thereby causes big harmonic distortion amount, both poor sound quality.
Prior art increases the signal amplitude of input signal in order to overcome above-mentioned defective, guarantees that simultaneously the harmonic distortion amount is few, has mainly adopted and has improved supply voltage and the technical method that reduces the gain of fully differential operational amplifier in the circuit.Though increase the amplitude that power source voltage can increase the audio frequency input variable, this method can increase the design cost of circuit and consume big power consumption, also can introduce big noise simultaneously; Signal to noise ratio when the gain that reduces circuit can reduce the small-signal input, but the amplitude output signal of circuit can be reduced, cause the power output of circuit to reduce.
[summary of the invention]
Technical problem to be solved in the utility model is to overcome existing defective in the above-mentioned prior art, promptly when big audio signal is imported, the problem that output causes harmonic distortion through occurring after the modulation and demodulation cutting the top, and a kind of audio-frequency power amplifier circuit that has automatic gain control is provided.
The utility model has adopted following technical proposal to solve its technical problem: a kind of audio-frequency power amplifier circuit that has automatic gain control, comprise a fully differential operational amplifier, this fully differential operational amplifier same, be equipped with divider resistance on the inverting input respectively, and between in-phase input end and the output, all be equipped with feedback resistance between inverting input and the output respectively, a biasing circuit is connected with this fully differential operational amplifier, it is characterized in that: also have an automatic gain control circuit, this automatic gain control circuit input connects the output of fully differential operational amplifier, a reference voltage circuit is connected with this automatic gain control circuit, and the output of this automatic gain control circuit is connected with adjustable resistance on the fully differential operational amplifier input.
The utility model is comparing through in the automatic gain control circuit output signal of fully differential operational amplifier with reference voltage, obtain a digital signal, and this digital signal gone to control variable resistor size before the fully differential operational amplifier input again, thereby realize the automatic adjusting of circuit gain.
[description of drawings]
Fig. 1 is a kind of traditional fully differential operation amplifier circuit structure chart in the prior art;
Fig. 2 is the utility model electrical block diagram;
Automatic gain control circuit in Fig. 3 the utility model (AGC) structural representation
Each sequence number is expressed as respectively among the figure:
1-adjustable resistance 1; 2-adjustable resistance 2;
The 3-feedback resistance; The 4-feedback resistance;
5-fully differential operational amplifier; 6-automatic gain control circuit (AGC);
7-audio output 8-reference voltage circuit;
The 9-biasing circuit; 10-operational amplifier (EA);
The 11-clamp circuit; 12-analog to digital conversion circuit (ADC).
[embodiment]
The utility model will be further described below in conjunction with embodiment and accompanying drawing.
With reference to Fig. 2, the utility model comprises a fully differential operational amplifier 5, is equipped with adjustable resistance 1, adjustable resistance 2 respectively on same, the inverting input of this fully differential operational amplifier 5.Between in-phase input end and output, be equipped with feedback resistance 3, between inverting input and output, be equipped with feedback resistance 4, a biasing circuit 9 is connected with this fully differential operational amplifier 5, the input of an automatic gain control circuit (AGC) 6 connects the audio output 7 of fully differential operational amplifier 5, reference voltage circuit 8 is connected with this automatic gain control circuit 6, and the output of this automatic gain control circuit 6 is connected with adjustable resistance 1,2 on the fully differential operational amplifier input.
With reference to Fig. 3, automatic gain control circuit 6 described in the utility model is made of operational amplifier 10, clamp circuit 11 and analog to digital conversion circuit 12.The in-phase input end of this operational amplifier 10 is connected with audio output 7 on the fully differential operational amplifier 5, its inverting input is connected with reference voltage circuit 8, the output of this operational amplifier 10 connects clamp circuit 11 inputs, the output of this clamp circuit 11 connects the input of analog to digital conversion circuit 12, and two outputs on this analog to digital conversion circuit 12 are connected with adjustable resistance 1,2 on 5 two inputs of fully differential operational amplifier respectively.
The input of automatic gain control circuit 6 described in the utility model, promptly the in-phase input end of this operational amplifier 10 can be connected with any end in two audio outputs 7 on the fully differential operational amplifier 5 in the circuit.
The particular circuit configurations of the reference voltage circuit 8 described in the utility model, biasing circuit 9, clamp circuit 11, analog to digital conversion circuit 12 all is a circuit of the prior art, is not giving unnecessary details here.
The circuit working principle is as follows in the utility model:
In the utility model by adjustable resistance 1,2; Fully differential operational amplifier 5; Feedback resistance 3,4 is formed operational amplifier and is amplified loop, and audio input signal is amplified.Audio signal after will amplifying is then come out the audio signal peak detection after this amplification through automatic gain control circuit (AGC) 6, is converted into digital signal again, thereby regulates the resistance of adjustable resistance 1,2, reaches the purpose of the gain that changes circuit.
Audio input signal is from the input port (Vi+ of fully differential operational amplifier 5, Vi-) input, after fully differential arithmetic unit 5 amplifies, output port (Vo+ from this operational amplifier 5, Vo-) output audio signal, this audio signal is connected to the input (IN+) of operational amplifier 10 (EA) in the automatic gain control circuit 6, and compares with the AGC reference voltage.
(1) when the audio output signal peak value less than the AGC reference voltage, be zero through the output voltage after operational amplifier 10 (EA); Signal after this amplification also is zero through the output behind the clamp circuit 11, because the output of clamp circuit 11 does not change, the input analog signal of analog to digital conversion circuit 12 (ADC) does not change yet, so the output of the digital signal of analog to digital conversion circuit 12 does not change, thereby the value of variable resistor 1,2 is constant, and the gain constant of circuit is constant.
(2) when the reference voltage of audio output signal peak value more than or equal to AGC, this audio output signal amplifies audio output signal through operational amplifier 10, again this signal is input to clamp circuit 11, the peak value of clamp circuit 11 these signals of output, and keep constant.This crest voltage changes into the output of string number signal through analog to digital conversion circuit 12 (ADC), this digital output signal is regulated the value of variable resistor 1,2, then change the gain of circuit, crest voltage increases, the resistance of adjustable resistance also increases, circuit gain reduces, and when strengthening input like this, it is constant to export the value that keeps constant.
In sum, of the present utility modelly can when small-signal is imported, be maintained fixed gain and amplify audio signal.When importing, big audio signal, guarantees that output audio signal can access the high linearity and low harmonic distortion by reducing the amplifying circuit closed loop gain.
Claims (3)
1. one kind has the audio-frequency power amplifier circuit that automatic gain is controlled, comprise a fully differential operational amplifier, this fully differential operational amplifier same, be equipped with divider resistance on the inverting input respectively, and between in-phase input end and the output, all be equipped with feedback resistance between inverting input and the output respectively, a biasing circuit is connected with this fully differential operational amplifier, it is characterized in that: also have an automatic gain control circuit, this automatic gain control circuit input connects the output of fully differential operational amplifier, a reference voltage circuit is connected with this automatic gain control circuit, and the output of this automatic gain control circuit is connected with adjustable resistance on the fully differential operational amplifier input.
2. the audio-frequency power amplifier circuit that has automatic gain control according to claim 1, it is characterized in that: described automatic gain control circuit is by operational amplifier, clamp circuit and analog to digital conversion circuit constitute, this operational amplifier in-phase input end is connected with audio output on the fully differential operational amplifier, its inverting input is connected with reference voltage circuit, this operational amplifier output terminal connects the clamp circuit input, this clamp circuit output connection mode number conversion circuit input end, two outputs on this analog to digital conversion circuit are connected with adjustable resistance on two inputs of fully differential operational amplifier respectively.
3. according to claim 1 or the 2 described audio-frequency power amplifier circuit that have automatic gain control, it is characterized in that: described automatic gain control circuit input, promptly this operational amplifier in-phase input end of circuit can be connected with any end of two audio outputs on the fully differential operational amplifier.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010201411380U CN201674469U (en) | 2010-03-25 | 2010-03-25 | Audio-frequency power amplifier circuit with automatic gain control circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010201411380U CN201674469U (en) | 2010-03-25 | 2010-03-25 | Audio-frequency power amplifier circuit with automatic gain control circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201674469U true CN201674469U (en) | 2010-12-15 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2010201411380U Expired - Lifetime CN201674469U (en) | 2010-03-25 | 2010-03-25 | Audio-frequency power amplifier circuit with automatic gain control circuit |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102201792A (en) * | 2010-03-25 | 2011-09-28 | 上海沙丘微电子有限公司 | Automatic gain control circuit of audio power amplifier |
| CN103018696A (en) * | 2011-09-28 | 2013-04-03 | 南京丹迪克科技开发有限公司 | Three-phase power harmonic standard source |
| CN103580634A (en) * | 2013-10-29 | 2014-02-12 | 中国电子科技集团公司第四十一研究所 | Automatic gain controller in audio signal analysis |
| CN104360158A (en) * | 2014-11-18 | 2015-02-18 | 国电南瑞科技股份有限公司 | Self-adaptive key phase collection circuit |
| CN108923757A (en) * | 2018-07-02 | 2018-11-30 | 成都九洲电子信息系统股份有限公司 | The detection of radio frequency power output closed loop and regulating device |
| CN109756269A (en) * | 2019-01-23 | 2019-05-14 | 西安电子科技大学 | A kind of visible light communication reception circuit |
| CN111903119A (en) * | 2018-03-12 | 2020-11-06 | 华为技术有限公司 | Full-band receiver and television tuner |
-
2010
- 2010-03-25 CN CN2010201411380U patent/CN201674469U/en not_active Expired - Lifetime
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102201792A (en) * | 2010-03-25 | 2011-09-28 | 上海沙丘微电子有限公司 | Automatic gain control circuit of audio power amplifier |
| CN103018696A (en) * | 2011-09-28 | 2013-04-03 | 南京丹迪克科技开发有限公司 | Three-phase power harmonic standard source |
| CN103580634A (en) * | 2013-10-29 | 2014-02-12 | 中国电子科技集团公司第四十一研究所 | Automatic gain controller in audio signal analysis |
| CN104360158A (en) * | 2014-11-18 | 2015-02-18 | 国电南瑞科技股份有限公司 | Self-adaptive key phase collection circuit |
| CN111903119A (en) * | 2018-03-12 | 2020-11-06 | 华为技术有限公司 | Full-band receiver and television tuner |
| CN111903119B (en) * | 2018-03-12 | 2022-05-24 | 华为技术有限公司 | Full-band receiver and television tuner |
| CN108923757A (en) * | 2018-07-02 | 2018-11-30 | 成都九洲电子信息系统股份有限公司 | The detection of radio frequency power output closed loop and regulating device |
| CN109756269A (en) * | 2019-01-23 | 2019-05-14 | 西安电子科技大学 | A kind of visible light communication reception circuit |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| ASS | Succession or assignment of patent right |
Owner name: SHANGHAI XINDI INFORMATION TECHNOLOGY CO., LTD. Free format text: FORMER OWNER: SHANGHAI SANDHILL MICROELECTRONICS CO., LTD. Effective date: 20130705 |
|
| C41 | Transfer of patent application or patent right or utility model | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20130705 Address after: 201108, No. 4299 Jin Du Road, Shanghai, Minhang District Patentee after: Shanghai Xindi Information Technology Co., Ltd. Address before: 203 room 1508, Guanghua Road, Shanghai, Minhang District 201108 Patentee before: Shanghai SandHill Microelectronics Co., Ltd. |
|
| ASS | Succession or assignment of patent right |
Owner name: XIAO GUOQING Free format text: FORMER OWNER: SHANGHAI XINDI INFORMATION TECHNOLOGY CO., LTD. Effective date: 20150216 |
|
| C41 | Transfer of patent application or patent right or utility model | ||
| COR | Change of bibliographic data |
Free format text: CORRECT: ADDRESS; FROM: 201108 MINHANG, SHANGHAI TO: 201199 MINHANG, SHANGHAI |
|
| TR01 | Transfer of patent right |
Effective date of registration: 20150216 Address after: 201199 Shanghai city Minhang District No. 6269 humin road Yinxiao building B building room 1704 Patentee after: Xiao Guoqing Address before: 201108, No. 4299 Jin Du Road, Shanghai, Minhang District Patentee before: Shanghai Xindi Information Technology Co., Ltd. |
|
| ASS | Succession or assignment of patent right |
Owner name: JIANGXI XINCHENG MICROELECTRONICS CO., LTD. Free format text: FORMER OWNER: XIAO GUOQING Effective date: 20150721 |
|
| C41 | Transfer of patent application or patent right or utility model | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20150721 Address after: 330013, Jiangxi Nanchang Nanchang Airport Economic Zone small and medium-sized micro enterprise Industrial Park office two floor Patentee after: Jiangxi core Microelectronics Co., Ltd. Address before: 201199 Shanghai city Minhang District No. 6269 humin road Yinxiao building B building room 1704 Patentee before: Xiao Guoqing |
|
| CX01 | Expiry of patent term |
Granted publication date: 20101215 |
|
| CX01 | Expiry of patent term |