CN106788304B - Automatic gain control circuit and audio equipment - Google Patents
Automatic gain control circuit and audio equipment Download PDFInfo
- Publication number
- CN106788304B CN106788304B CN201710054270.4A CN201710054270A CN106788304B CN 106788304 B CN106788304 B CN 106788304B CN 201710054270 A CN201710054270 A CN 201710054270A CN 106788304 B CN106788304 B CN 106788304B
- Authority
- CN
- China
- Prior art keywords
- unit
- resistor
- capacitor
- output
- voltage
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 230000003321 amplification Effects 0.000 claims abstract description 140
- 238000003199 nucleic acid amplification method Methods 0.000 claims abstract description 140
- 238000001914 filtration Methods 0.000 claims abstract description 6
- 239000003990 capacitor Substances 0.000 claims description 72
- 230000035945 sensitivity Effects 0.000 abstract description 9
- 238000010586 diagram Methods 0.000 description 6
- 230000007423 decrease Effects 0.000 description 3
- 230000003111 delayed effect Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03G—CONTROL OF AMPLIFICATION
- H03G3/00—Gain control in amplifiers or frequency changers
- H03G3/20—Automatic control
- H03G3/30—Automatic control in amplifiers having semiconductor devices
- H03G3/3005—Automatic control in amplifiers having semiconductor devices in amplifiers suitable for low-frequencies, e.g. audio amplifiers
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03G—CONTROL OF AMPLIFICATION
- H03G2201/00—Indexing scheme relating to subclass H03G
- H03G2201/40—Combined gain and bias control
Landscapes
- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Control Of Amplification And Gain Control (AREA)
Abstract
The invention discloses an automatic gain control circuit and audio equipment, and relates to the field of signal processing. The invention adopts the automatic gain control circuit comprising a preceding stage amplification unit, an output following unit, a voltage-multiplying rectification unit, a quick response unit and an amplification factor adjusting unit, and the preceding stage amplification unit and the output following unit carry out two-stage amplification on an input signal; the voltage-multiplying rectifying unit is used for rectifying and filtering the input signal subjected to the two-stage amplification to generate a negative voltage, and the negative voltage and the positive power supply voltage act on the input end of the amplification factor adjusting unit together; the amplification factor of the preceding stage amplification unit is proportionally adjusted by the amplification factor adjustment unit according to the voltage of the input end of the amplification factor adjustment unit, so that when the amplitude of an input signal is small, the amplification factor of the preceding stage amplification unit is large, and the receiving sensitivity of a circuit is not influenced; and the quick response unit directly couples the output signal to the output end of the preceding stage amplification unit, so that the response speed of the circuit is improved.
Description
Technical Field
The invention belongs to the field of signal processing, and particularly relates to an automatic gain control circuit and audio equipment.
Background
An Automatic Gain Control (AGC) circuit is usually disposed in an audio device (e.g., a sound box, a radio, etc.) and is used for amplifying an input signal, and the AGC circuit can automatically adjust a Gain of an amplifier according to a voltage amplitude of the input signal, so that when the amplitude of the input signal changes greatly, the voltage amplitude of an output signal is stable and unchanged or changes within a small range.
The conventional audio equipment uses a simple AGC circuit (as shown in fig. 1), which includes a pre-amplifier unit, an output follower unit, a voltage-doubler rectifier unit, and a pre-amplifier. After the input signal passes through the pre-stage amplification unit and the output following unit, the voltage-multiplying rectification unit performs voltage-multiplying rectification on the input signal subjected to two-stage amplification to generate a voltage which is negative with respect to the ground and acts on the base of the pre-stage amplifier together with a positive power supply voltage. When the voltage amplitude of the input signal is small, the negative voltage is also present, which results in a decrease in the receiving sensitivity of the circuit, and the feedback signal acts on the input terminal of the preceding stage amplification unit, which results in a slow response speed of the circuit.
In summary, the conventional simple agc circuit has the problems of low receiving sensitivity and slow response speed when small signals are input.
Disclosure of Invention
The invention aims to provide an automatic gain control circuit and audio equipment, and aims to solve the problems of low receiving sensitivity and low response speed in small signal input of the conventional simple automatic gain control circuit.
The invention is realized in this way, an automatic gain control circuit, including preceding stage amplification unit, output following unit and voltage-multiplying rectification unit, the said automatic gain control circuit also includes: a quick response unit and a magnification adjustment unit;
the input end of the preceding stage amplification unit is the input end of the automatic gain control circuit, the output end of the preceding stage amplification unit is connected with the input end of the output following unit, the output end of the output following unit is the output end of the automatic gain control circuit, the input end of the rapid response unit and the input end of the voltage doubling rectification unit are commonly connected with the output end of the output following unit, the output end of the rapid response unit is connected with the output end of the preceding stage amplification unit, and the input end and the output end of the amplification factor adjustment unit are respectively connected with the output end of the voltage doubling rectification unit and the feedback end of the preceding stage amplification unit;
the pre-stage amplification unit and the output following unit sequentially perform first-stage amplification and second-stage amplification on an input signal, and the output following unit outputs the input signal subjected to the two-stage amplification; the voltage-multiplying rectifying unit is used for rectifying and filtering the input signal subjected to the two-stage amplification, generating a voltage which is negative with respect to the ground, and enabling the voltage which is negative with respect to the ground and a positive power supply voltage to jointly act on an input end of the amplification factor adjusting unit; the amplification factor adjusting unit adjusts the amplification factor of the preceding stage amplification unit in a positive proportion according to the voltage of the input end of the amplification factor adjusting unit; the quick response unit couples the signal output by the output following unit to the output end of the pre-stage amplification unit.
The invention also provides audio equipment, which comprises an audio output unit and the automatic gain control circuit, wherein the audio output unit comprises a first amplifier and a second amplifier;
and the output end of the automatic gain control circuit is connected with the input end of the audio output unit.
According to the invention, by adopting the automatic gain control circuit comprising the pre-stage amplification unit, the output following unit, the voltage-multiplying rectification unit, the quick response unit and the amplification factor adjusting unit, the pre-stage amplification unit and the output following unit sequentially perform first-stage amplification and second-stage amplification on an input signal, and the output following unit outputs the input signal subjected to the two-stage amplification; the voltage-multiplying rectifying unit is used for rectifying and filtering the input signal subjected to the two-stage amplification, generating a voltage which is negative to the ground, and enabling the voltage which is negative to the ground and the positive power supply voltage to jointly act on the input end of the amplification factor adjusting unit; the amplification factor of the preceding stage amplification unit is proportionally adjusted by the amplification factor adjustment unit according to the voltage of the input end of the amplification factor adjustment unit, so that when the voltage amplitude of an input signal is small, the amplification factor of the preceding stage amplification unit is large, and the receiving sensitivity of the whole circuit is not influenced; and because the quick response unit directly couples the signal output by the output following unit to the output end of the preceding stage amplification unit, the response speed of the circuit is improved, and the delay of the output signal is avoided.
Drawings
Fig. 1 is a schematic block diagram of an automatic gain control circuit provided in the prior art;
fig. 2 is a schematic block diagram of an automatic gain control circuit according to an embodiment of the present invention;
fig. 3 is a schematic circuit diagram of an automatic gain control circuit according to an embodiment of the present invention;
fig. 4 is a schematic block diagram of an audio device according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Fig. 2 is a schematic block diagram of an agc circuit according to an embodiment of the present invention, and for convenience of description, only the parts related to the embodiment of the present invention are shown, and the details are as follows:
as shown in fig. 2, an automatic gain control circuit 1 includes a pre-stage amplifying unit 10, an output follower unit 20, and a voltage-doubler rectifying unit 30, and the automatic gain control circuit 1 further includes: a fast response unit 40 and a magnification adjustment unit 50.
The input end of the preceding stage amplification unit 10 is the input end of the automatic gain control circuit 1, the output end of the preceding stage amplification unit 10 is connected with the input end of the output following unit 20, the output end of the output following unit 20 is the output end of the automatic gain control circuit 1, the input end of the fast response unit 40 and the input end of the voltage doubling rectification unit 30 are connected to the output end of the output following unit 20 in common, the output end of the fast response unit 40 is connected with the output end of the preceding stage amplification unit 10, and the input end and the output end of the amplification factor adjustment unit 50 are connected with the output end of the voltage doubling rectification unit 30 and the feedback end of the preceding stage amplification unit 10 respectively.
The pre-amplification unit 10 and the output following unit 20 sequentially perform first-stage amplification and second-stage amplification on the input signal, and the output following unit 20 outputs the input signal subjected to the two-stage amplification; the voltage-multiplying rectifying unit 30 rectifies and filters the input signal subjected to the two-stage amplification, generates a voltage negative to ground, and applies the voltage negative to ground and the positive power supply voltage to the input end of the amplification factor adjusting unit 50; the amplification factor adjusting unit 50 adjusts the amplification factor of the preceding stage amplifying unit 10 in a direct proportion according to the voltage at the input end; the fast response unit 40 couples the signal output by the output follower unit 20 to the output of the pre-amplifier unit 10.
In the embodiment of the present invention, the amplification factor adjusting unit 50 performs a proportional adjustment on the amplification factor of the pre-stage amplifying unit 10 according to the voltage at the input terminal thereof. That is, the higher the voltage at the input terminal of the amplification factor adjusting unit 50 is, the larger the amplification factor of the preceding stage amplification unit 10 is adjusted by the amplification factor adjusting unit 50; the lower the voltage at the input terminal of the amplification factor adjustment unit 50, the smaller the amplification factor adjustment unit 50 adjusts the amplification factor of the preceding stage amplification unit 10.
Specifically, when the amplitude of the input signal is small, the absolute value of the negative voltage to ground generated by the voltage-doubling rectifying unit 30 is small, and the negative voltage and the positive power voltage act on the input end of the amplification factor adjusting unit 50 together, so that the voltage at the input end of the amplification factor adjusting unit 50 is high, at this time, the amplification factor adjusting unit 50 adjusts the amplification factor adjustment of the pre-stage amplifying unit 10, so that the amplification factor of the pre-stage amplifying unit 10 is large, and the receiving sensitivity of the circuit is not affected even when the amplitude of the input signal is small. And since the fast response unit 40 directly couples the signal output by the output follower unit 20 to the output terminal of the pre-amplifier unit 10, the response speed of the circuit is increased, so that the output signal is not delayed.
Fig. 3 is a schematic circuit diagram of an automatic gain control circuit according to an embodiment of the present invention, and for convenience of description, only the portions related to the embodiment of the present invention are shown, and the details are as follows:
as shown in fig. 3, as an embodiment of the present invention, the fast response unit 40 is a ninth capacitor C9.
The first terminal and the second terminal of the ninth capacitor C9 are the output terminal and the input terminal of the fast response unit 40, respectively.
As an embodiment of the present invention, the magnification adjustment unit 50 includes: an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, a twelfth resistor R12, a thirteenth capacitor C13, and a first switch Q1.
A first end of the twelfth resistor R12, a first end of the thirteenth capacitor C13, and a high potential end of the first switch tube Q1 are commonly connected as an output end of the amplification factor adjusting unit 50, a second end of the twelfth resistor R12 is grounded, a second end of the thirteenth capacitor C13 is connected to a first end of the eighth resistor R8, a control end of the first switch tube Q1 is connected to a first end of the ninth resistor R9, a second end of the eighth resistor R8 and a second end of the ninth resistor R9 are commonly connected to a first end of the tenth resistor R10, a second end of the tenth resistor R10 is an input end of the amplification factor adjusting unit 50, and a low potential end of the first switch tube Q1 is grounded.
In the embodiment of the present invention, the first switch Q1 may be an NMOS transistor. Wherein, the grid, the drain and the source of the NMOS tube are respectively the control end, the high potential end and the low potential end of the first switch tube Q1.
Of course, the first switch transistor Q1 can also be a P-JFET transistor, which is specifically configured according to actual requirements, and is not limited herein.
In the embodiment of the present invention, since the NMOS transistor has the dynamic on-resistance, and the resistance of the dynamic on-resistance is inversely proportional to the gate voltage of the NMOS transistor, the dynamic adjustment of the amplification factor of the pre-stage amplification unit 10 can be realized.
As an embodiment of the present invention, the pre-amplification unit 10 includes: the circuit comprises a first operational amplifier U1A, a first capacitor C1, a first resistor R1, a third capacitor C3, a third resistor R3, a fifth capacitor C5, an eighth capacitor C8, a sixth resistor R6, a seventh resistor R7 and a twelfth capacitor C12.
A first end of the third capacitor C3 and a first end of the fifth capacitor C5 are commonly connected to be an input end of the pre-amplifier unit 10, a second end of the fifth capacitor C5 is grounded, a second end of the third capacitor C3 and a first end of the third resistor R3 are connected to be a non-inverting input end of the first operational amplifier U1A, a second end of the first resistor R1 and a second end of the first capacitor C1 are commonly connected to the first power VDD, a first end of the first capacitor C1 is grounded, a first end of the eighth capacitor C8 is a feedback end of the pre-amplifier unit 10, a second end of the eighth capacitor C8 and a first end of the sixth resistor R6 are commonly connected to be an inverting input end of the first operational amplifier U1A, an output end of the first operational amplifier U1A is an output end of the pre-amplifier unit 10, and a second end of the seventh resistor R7 and a first end of the twelfth capacitor C12 are commonly connected to be an inverting input end of the first operational amplifier U1A.
As an embodiment of the present invention, the output follower unit 20 includes: the circuit comprises a second operational amplifier U1B, a fourth capacitor C4, a fourth resistor R4, a fifth resistor R5, a second resistor R2, a second capacitor C2, a tenth capacitor C10 and an eleventh capacitor C11.
A first end of the fourth capacitor C4 is an input end of the output follower unit 20, a second end of the fourth capacitor C4 is connected to a first end of the fourth resistor R4, a second end of the fourth resistor R4, a first end of the fifth resistor R5, and a first end of the second capacitor C2 are commonly connected to a first end of the second resistor R2, a second end of the second resistor R2 and a second end of the second capacitor C2 are commonly connected to an output end of the second operational amplifier U1B, an output end of the second operational amplifier U1B is an output end of the output follower unit 20, a second end of the fifth resistor R5 and a first end of the eleventh capacitor C11 are commonly connected to an inverting input end of the second operational amplifier U1B, a second end of the eleventh capacitor C11 is grounded, a first end of the tenth capacitor C10 and a non-inverting input end of the second operational amplifier U1B are commonly connected to the first power supply VDD, and a second end of the tenth capacitor C10 is grounded.
As an embodiment of the present invention, the voltage-doubler rectification unit 30 includes: a first diode D1, an eleventh resistor R11, a tenth capacitor C10, a second diode D2, a fourteenth resistor R14, a third diode D3, and a thirteenth resistor R13.
A first end of the tenth capacitor C10, a cathode of the second diode D2, a first end of the fourteenth resistor R14, and a cathode of the first diode D1 are commonly connected as an output end of the voltage-doubler rectification unit 30, an anode of the first diode D1, a cathode of the third diode D3, and a first end of the thirteenth resistor R13 are commonly connected to a first end of the eleventh resistor R11, a second end of the eleventh resistor R11 is an input end of the voltage-doubler rectification unit 30, and a second end of the tenth capacitor C10, an anode of the second diode D2, a second end of the fourteenth resistor R14, an anode of the third diode D3, and a second end of the thirteenth resistor R13 are commonly connected to ground.
In the embodiment of the present invention, the automatic gain control circuit 1 further includes a sixth capacitor C6 and a fourteenth capacitor C14, which are used for filtering the signal output by the second operational amplifier U1B.
In the embodiment of the invention, the first operational amplifier U1A and the second operational amplifier U1B may both adopt operational amplifiers with model number JRC 4558. Of course, the first operational amplifier U1A and the second operational amplifier U1B may also adopt operational amplifiers of other types, which are specifically set according to actual requirements, and are not limited here.
The following further describes an automatic gain control circuit provided in an embodiment of the present invention with reference to specific operating principles:
as shown in fig. 3, an input signal is input from the non-inverting input terminal of the first operational amplifier U1A, and the first operational amplifier U1A has a high amplification characteristic, so that the input sensitivity can be improved. The first operational amplifier U1A and the second operational amplifier U1B sequentially perform first-stage amplification and second-stage amplification on an input signal, and the amplification factor Av = Av1A + Av1B of the whole circuit. Where Av1a is the amplification factor of the preceding stage amplification unit 10, and Av1b is the amplification factor of the output follower unit 20. The amplification factor Av1b = R2/R3 of the output follower unit 20, and since the resistance values of the second resistor R2 and the third resistor R3 are both fixed values, the amplification factor Av1b of the output follower unit 20 is a fixed value. The amplification factor Av1a = R7/(R6 + Rd) of the pre-stage amplification unit 10. Wherein Rd is the dynamic on-resistance of the first switching tube Q1. The resistance value of Rd is inversely proportional to the voltage of the gate of the first switching tube Q1, that is, the resistance value of Rd decreases with the increase of the voltage of the gate of the first switching tube Q1, or the resistance value of Rd increases with the decrease of the voltage of the gate of the first switching tube Q1. Because the gate bias voltage of the first switching tube Q1 is obtained by performing voltage-doubling rectification on the input signal subjected to two-stage amplification by the voltage-doubling rectification unit 30, when the voltage amplitude of the input signal is small, the first switching tube Q1 can still be turned on, at this time, because the negative voltage is small, the gate voltage of the first switching tube Q1 is large, the resistance value of the dynamic on-resistance Rd of the first switching tube Q1 is small, and the amplification factor Av1A of the first operational amplifier U1A is large, so that the receiving sensitivity of the circuit is not affected when a small signal is input. Meanwhile, the ninth capacitor C9 directly couples the signal output by the second operational amplifier U1B to the output terminal of the first operational amplifier U1A, so that the fast response of the circuit is realized.
Fig. 4 shows a module structure of an audio device according to an embodiment of the present invention, and for convenience of description, only the relevant parts related to the embodiment of the present invention are shown, which are detailed as follows:
as shown in fig. 4, an audio device 100 includes an audio output unit 2, and further includes the above-mentioned automatic gain control circuit 1.
The output end of the automatic gain control circuit 1 is connected with the input end of the audio output unit 2.
In the embodiment of the present invention, the audio device 100 may be an audio device such as a sound box, a radio, or a speaker, or may be other types of audio devices, which is determined according to actual situations, and is not limited herein.
It should be noted that the circuit structure of the agc circuit 1 in the embodiment corresponding to fig. 4 is completely the same as the circuit structure of the agc circuit 1 in the embodiment corresponding to fig. 3, and please refer to the related description in the embodiments corresponding to fig. 3 and fig. 3, which is not repeated herein.
According to the embodiment of the invention, the automatic gain control circuit comprising the pre-amplification unit, the output following unit, the voltage-multiplying rectification unit, the quick response unit and the amplification factor adjusting unit is adopted, the pre-amplification unit and the output following unit sequentially perform first-stage amplification and second-stage amplification on an input signal, and the output following unit outputs the input signal subjected to the two-stage amplification; the voltage-multiplying rectifying unit is used for rectifying and filtering the input signal subjected to the two-stage amplification, generating a voltage which is negative to the ground, and enabling the voltage which is negative to the ground and the positive power supply voltage to jointly act on the input end of the amplification factor adjusting unit; the amplification factor of the preceding stage amplification unit is proportionally adjusted by the amplification factor adjustment unit according to the voltage of the input end of the amplification factor adjustment unit, so that when the voltage amplitude of an input signal is small, the amplification factor of the preceding stage amplification unit is large, and the receiving sensitivity of the whole circuit is not influenced; and because the quick response unit directly couples the signal output by the output following unit to the output end of the preceding stage amplification unit, the response speed of the circuit is improved, and the delay of the output signal is avoided.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
Claims (8)
1. An automatic gain control circuit, includes preceding stage amplification unit, output follow unit and voltage-multiplying rectification unit, its characterized in that, automatic gain control circuit still includes: a quick response unit and a magnification adjustment unit;
the input end of the preceding stage amplification unit is the input end of the automatic gain control circuit, the output end of the preceding stage amplification unit is connected with the input end of the output following unit, the output end of the output following unit is the output end of the automatic gain control circuit, the input end of the rapid response unit and the input end of the voltage doubling rectification unit are commonly connected with the output end of the output following unit, the output end of the rapid response unit is connected with the output end of the preceding stage amplification unit, and the input end and the output end of the amplification factor adjustment unit are respectively connected with the output end of the voltage doubling rectification unit and the feedback end of the preceding stage amplification unit;
the pre-stage amplification unit and the output following unit sequentially perform first-stage amplification and second-stage amplification on an input signal, and the output following unit outputs the input signal subjected to the two-stage amplification; the voltage-multiplying rectifying unit is used for rectifying and filtering the input signal subjected to the two-stage amplification, generating a voltage which is negative with respect to the ground, and enabling the voltage which is negative with respect to the ground and a positive power supply voltage to jointly act on an input end of the amplification factor adjusting unit; the amplification factor adjusting unit adjusts the amplification factor of the preceding stage amplification unit in a positive proportion according to the voltage of the input end of the amplification factor adjusting unit; the higher the voltage at the input end of the amplification factor adjusting unit is, the larger the amplification factor adjusting unit adjusts the amplification factor of the preceding stage amplification unit to be larger, and the lower the voltage at the input end of the amplification factor adjusting unit is, the smaller the amplification factor adjusting unit adjusts the amplification factor of the preceding stage amplification unit to be smaller; the quick response unit couples the signal output by the output following unit to the output end of the pre-stage amplification unit.
2. The automatic gain control circuit of claim 1 wherein said fast response unit is a ninth capacitor;
and a first end and a second end of the ninth capacitor are respectively an output end and an input end of the fast response unit.
3. The automatic gain control circuit of claim 1, wherein the amplification adjustment unit comprises: the circuit comprises an eighth resistor, a ninth resistor, a tenth resistor, a twelfth resistor, a thirteenth capacitor and a first switch tube;
a first end of the twelfth resistor, a first end of the thirteenth capacitor and a high potential end of the first switching tube are connected in common to serve as an output end of the amplification adjustment unit, a second end of the twelfth resistor is connected to ground, a second end of the thirteenth capacitor is connected to a first end of the eighth resistor, a control end of the first switching tube is connected to a first end of the ninth resistor, a second end of the eighth resistor and a second end of the ninth resistor are connected in common to a first end of the tenth resistor, a second end of the tenth resistor is an input end of the amplification adjustment unit, and a low potential end of the first switching tube is connected to ground.
4. The automatic gain control circuit of claim 1, wherein said pre-amplifier unit comprises: the circuit comprises a first operational amplifier, a first capacitor, a first resistor, a third capacitor, a third resistor, a fifth capacitor, an eighth capacitor, a sixth resistor, a seventh resistor and a twelfth capacitor;
the first end of the third capacitor and the first end of the fifth capacitor are connected in common to serve as the input end of the pre-stage amplification unit, the second end of the fifth capacitor is grounded, the second end of the third capacitor and the first end of the third resistor are connected, the second end of the third resistor and the second end of the first resistor are connected in common to the non-inverting input end of the first operational amplifier, the first end of the first resistor and the second end of the first capacitor are connected in common to a first power supply, the first end of the first capacitor is grounded, the first end of the eighth capacitor is the feedback end of the pre-stage amplification unit, the second end of the eighth capacitor is connected with the first end of the sixth resistor, the second end of the sixth resistor, the first end of the seventh resistor and the first end of the twelfth capacitor are connected in common to the inverting input end of the first operational amplifier, the output end of the first operational amplifier is the output end of the pre-stage amplification unit, and the second end of the seventh resistor and the second end of the twelfth capacitor are connected in common to the output end of the first operational amplifier.
5. The automatic gain control circuit of claim 1 wherein said output follower unit comprises: the second operational amplifier, a fourth capacitor, a fourth resistor, a fifth resistor, a second capacitor, a tenth capacitor and an eleventh capacitor;
the first end of the fourth capacitor is the input end of the output follower unit, the second end of the fourth capacitor is connected with the first end of the fourth resistor, the second end of the fourth resistor, the first end of the fifth resistor and the first end of the second capacitor are connected to the first end of the second resistor in common, the second end of the second resistor and the second end of the second capacitor are connected to the output end of the second operational amplifier in common, the output end of the second operational amplifier is the output end of the output follower unit, the second end of the fifth resistor and the first end of the eleventh capacitor are connected to the inverting input end of the second operational amplifier in common, the second end of the eleventh capacitor is grounded, the first end of the tenth capacitor and the non-inverting input end of the second operational amplifier are connected to the first power supply in common, and the second end of the tenth capacitor is grounded.
6. The automatic gain control circuit of claim 1 wherein said voltage doubler rectification unit comprises: the circuit comprises a first diode, an eleventh resistor, a tenth capacitor, a second diode, a fourteenth resistor, a third diode and a thirteenth resistor;
a first end of the tenth capacitor, a cathode of the second diode, a first end of the fourteenth resistor, and a cathode of the first diode are commonly connected as an output end of the voltage-doubler rectifier unit, an anode of the first diode, a cathode of the third diode, and a first end of the thirteenth resistor are commonly connected to a first end of the eleventh resistor, a second end of the eleventh resistor is an input end of the voltage-doubler rectifier unit, and a second end of the tenth capacitor, an anode of the second diode, a second end of the fourteenth resistor, an anode of the third diode, and a second end of the thirteenth resistor are commonly connected to ground.
7. The automatic gain control circuit of claim 3 wherein said first switch transistor is an NMOS transistor;
the grid electrode, the drain electrode and the source electrode of the NMOS tube are respectively a control end, a high potential end and a low potential end of the first switch tube.
8. An audio device comprising an audio output unit, characterized in that the audio device further comprises an automatic gain control circuit according to any one of claims 1 to 7;
and the output end of the automatic gain control circuit is connected with the input end of the audio output unit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710054270.4A CN106788304B (en) | 2017-01-24 | 2017-01-24 | Automatic gain control circuit and audio equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710054270.4A CN106788304B (en) | 2017-01-24 | 2017-01-24 | Automatic gain control circuit and audio equipment |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN106788304A CN106788304A (en) | 2017-05-31 |
| CN106788304B true CN106788304B (en) | 2023-04-07 |
Family
ID=58943337
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710054270.4A Active CN106788304B (en) | 2017-01-24 | 2017-01-24 | Automatic gain control circuit and audio equipment |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN106788304B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107565921B (en) * | 2017-10-11 | 2024-04-05 | 绍兴职业技术学院 | Automatic circulation programmable amplifying circuit capable of being compared |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201682458U (en) * | 2010-03-03 | 2010-12-22 | 陈耀华 | Automatic gain control magnifier and low noise hearing aid system |
| CN203761342U (en) * | 2013-12-24 | 2014-08-06 | 青岛歌尔声学科技有限公司 | Variable gain amplification circuit and signal processing device |
| CN106160688A (en) * | 2016-07-18 | 2016-11-23 | 华南理工大学 | A kind of automatic gain control circuit based on photoconductive resistance |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101499783B (en) * | 2008-01-31 | 2012-05-16 | 鸿富锦精密工业（深圳）有限公司 | Gain automatic regulating circuit and electronic product using same |
-
2017
- 2017-01-24 CN CN201710054270.4A patent/CN106788304B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201682458U (en) * | 2010-03-03 | 2010-12-22 | 陈耀华 | Automatic gain control magnifier and low noise hearing aid system |
| CN203761342U (en) * | 2013-12-24 | 2014-08-06 | 青岛歌尔声学科技有限公司 | Variable gain amplification circuit and signal processing device |
| CN106160688A (en) * | 2016-07-18 | 2016-11-23 | 华南理工大学 | A kind of automatic gain control circuit based on photoconductive resistance |
Also Published As
| Publication number | Publication date |
|---|---|
| CN106788304A (en) | 2017-05-31 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101271344B (en) | High-power supply noise restraint low-voltage difference voltage regulator | |
| CN101826844B (en) | Power amplifier and signal amplifying method based on power amplifier | |
| CN103838287B (en) | A kind of linear voltage regulator of offset zero point dynamic conditioning | |
| US7622992B2 (en) | Power amplifier circuit having a bias signal inputted into input terminal and method thereof | |
| US10333473B1 (en) | Stabilizing high performance audio amplifiers | |
| US20130156226A1 (en) | Volume adjustment circuit with automatic gain control and electronic device using same | |
| CN108183690B (en) | Audio voltage follower circuit | |
| CN113037222B (en) | Bias circuit and amplifier | |
| CN103760943B (en) | A kind of slew rate enhancing circuit being applied to LDO | |
| US7342454B2 (en) | Analog multistage amplification circuit in the field of sensor | |
| JP2018169719A (en) | Power supply circuit | |
| KR20150054214A (en) | Sensor read out integrated circuit of capacitor type | |
| CN106788304B (en) | Automatic gain control circuit and audio equipment | |
| CN106026940B (en) | A kind of DC bias circuit of trans-impedance amplifier | |
| CN207442795U (en) | Suitable for low noise, the high bandwidth trans-impedance amplifier of wide dynamic range | |
| JP4573602B2 (en) | Amplifier | |
| US20080317262A1 (en) | Microphone Having an Output Signal Amplifier | |
| CN208890774U (en) | A kind of circuit structure improving load switch stability | |
| KR20130044576A (en) | Sound detect circuit and amplifier circuit thereof | |
| TWI508437B (en) | Voltage adjusting circuit for amplifier circuit and method thereof | |
| KR20110068613A (en) | Analog circuit with improved response speed feature | |
| CN107368139B (en) | Low-noise L DO of integrated chip circuit | |
| CN104104345A (en) | Low-noise microphone input amplifier | |
| JP2012151539A (en) | Transmission power control circuit | |
| TW202109056A (en) | Logarithmic power detector |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |