CN115395907A - Variable gain amplifier - Google Patents
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- CN115395907A CN115395907A CN202211022718.1A CN202211022718A CN115395907A CN 115395907 A CN115395907 A CN 115395907A CN 202211022718 A CN202211022718 A CN 202211022718A CN 115395907 A CN115395907 A CN 115395907A
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- 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
- H03G3/3036—Automatic control in amplifiers having semiconductor devices in high-frequency amplifiers or in frequency-changers
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/189—High-frequency amplifiers, e.g. radio frequency amplifiers
- H03F3/19—High-frequency amplifiers, e.g. radio frequency amplifiers with semiconductor devices only
- H03F3/195—High-frequency amplifiers, e.g. radio frequency amplifiers with semiconductor devices only in integrated circuits
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
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- H03F2200/451—Indexing scheme relating to amplifiers the amplifier being a radio frequency amplifier
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Abstract
The application provides a variable gain amplifier, and relates to the technical field of electronics. The variable gain amplifier includes: the input end of the variable gain unit is used as the input end of the variable gain amplifier, the control end of the variable gain unit is used for receiving an input gain control signal to adjust the gain range, the output end of the gain unit can be programmed to be connected with the input end of the first fixed gain unit, the output end of the at least one fixed gain unit is sequentially connected with the input end of the next fixed gain unit in a cascade mode, and the output end of the last fixed gain unit is used as the output end of the variable gain amplifier. The gain range of the variable gain amplifier can be enlarged, and the gain control precision is improved.
Description
Technical Field
The invention relates to the technical field of electronics, in particular to a variable gain amplifier.
Background
As an important module of a communication system, research on radio frequency transceiving links has been a central focus in the fields of communication technology and integrated circuits.
In an actual communication environment, due to interference of environmental factors, the Gain of the rf transceiving link in the communication device tends to vary widely, and therefore, a Variable Gain Amplifier (VGA) is generally disposed in the rf transceiving link for providing a Variable Gain to achieve a constant output signal power.
The variable gain step of the existing variable gain amplifier is large, so that the gain control precision of the variable gain amplifier is poor.
Disclosure of Invention
The present invention is directed to a variable gain amplifier to improve the accuracy of gain control, which overcomes the above-mentioned shortcomings of the prior art.
In order to achieve the above purpose, the technical solutions adopted in the embodiments of the present application are as follows:
in a first aspect, an embodiment of the present application provides a variable gain amplifier, including: a variable gain unit, at least one fixed gain unit;
the input end of the variable gain unit is used as the input end of the variable gain amplifier, and the control end of the variable gain unit is used for receiving an input gain control signal so as to adjust the gain range; the output end of the variable gain unit is connected with the input end of the first fixed gain unit, the output end of at least one fixed gain unit is sequentially cascaded with the input end of the next fixed gain unit, and the output end of the last fixed gain unit is used as the output end of the variable gain amplifier.
Optionally, the variable gain amplifier further includes: a numerical control adjusting unit;
at least one output end of the numerical control adjusting unit is connected with the control end of the at least one fixed gain unit to control the at least one fixed gain unit to start or close a gain function.
Optionally, the variable gain amplifier further includes: a controllable voltage unit;
the controllable voltage unit is connected with the control end of the variable gain unit.
Optionally, the variable gain amplifier further includes: at least one filtering unit;
one filter unit is connected between the variable gain unit and the first fixed gain unit, and the other filter units are connected between two adjacent fixed gain units.
Optionally, the variable gain unit includes: a transconductance unit and a transimpedance unit;
the input end of the transconductance unit is used as the input end of the variable gain unit, the output end of the transconductance unit is connected with the input end of the transimpedance unit, and the output end of the transimpedance unit is used as the output end of the variable gain unit.
Optionally, the transconductance unit includes: a differential input pair transistor consisting of a first transistor and a second transistor;
the grid electrode of the first transistor and the grid electrode of the second transistor are used as two differential input ends of the transconductance unit, the source electrode of the first transistor and the source electrode of the second transistor are grounded through a current source, and the drain electrode of the first transistor and the drain electrode of the second transistor are respectively connected with two input ends of the transimpedance unit.
Optionally, the transimpedance unit includes: the circuit comprises a third transistor, a fourth transistor, a fifth transistor, a sixth transistor, a seventh transistor, an eighth transistor, a first feedback resistor and a second feedback resistor;
the drain electrode of the third transistor and the drain electrode of the sixth transistor are used as two input ends of the transimpedance unit, and the source electrode of the third transistor is connected with the source electrode of the fourth transistor, the source electrode of the fifth transistor and the source electrode of the sixth transistor;
the drain electrode of the fourth transistor is connected with the drain electrode of the seventh transistor and one end of the first feedback resistor, and the grid electrode of the seventh transistor and the other end of the first feedback resistor are connected with one output end of the transconductance unit;
the drain of the fifth transistor is connected with the drain of the eighth transistor and one end of the second feedback resistor, and the gate of the eighth transistor and the other end of the second feedback resistor are connected with the other output end of the transconductance unit;
the grid electrode of the third transistor is connected with the grid electrode of the fourth transistor, and the grid electrode of the fifth transistor is connected with the grid electrode of the sixth transistor;
the source of the seventh transistor and the source of the eighth transistor are grounded through a current source, and the drain of the fourth transistor and the drain of the fifth transistor are used as two output ends of the transimpedance unit.
Optionally, the transimpedance unit further includes: a first capacitor and a second capacitor;
the first capacitor is connected in parallel at two ends of the first feedback resistor, and the second capacitor is connected in parallel at two ends of the second feedback resistor.
Optionally, the transimpedance unit further includes: the circuit comprises a first resistor, a second resistor, a third resistor and a fourth resistor;
the first resistor is connected in parallel across the source and the drain of the third transistor, the second resistor is connected in parallel across the source and the drain of the fourth transistor, the third resistor is connected in parallel across the source and the drain of the fifth transistor, and the fourth resistor is connected in parallel across the source and the drain of the sixth transistor.
Optionally, the first feedback resistor and the second feedback resistor are adjustable resistors.
The beneficial effect of this application is:
the application provides a variable gain amplifier, comprising: the input end of the variable gain unit is used as the input end of the variable gain amplifier, the control end of the variable gain unit is used for receiving an input gain control signal to adjust the gain range, the output end of the programmable gain unit is connected with the input end of the first fixed gain unit, the output end of the at least one fixed gain unit is sequentially connected with the input end of the next fixed gain unit in a cascade mode, and the output end of the last fixed gain unit is used as the output end of the variable gain amplifier. By controlling the gain range and the gain step length of the variable gain unit, the variable gain amplifier with wide gain range and small gain step length can be realized, and the gain control precision of the variable gain amplifier is improved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.
Fig. 1 is a schematic structural diagram of a first embodiment of a variable gain amplifier provided in the present application;
fig. 2 is a schematic structural diagram of a second embodiment of a variable gain amplifier provided in the present application;
fig. 3 is a schematic structural diagram of a variable gain unit according to an embodiment of the present application;
fig. 4 is a schematic circuit diagram of a variable gain unit according to an embodiment of the present application;
fig. 5 is a schematic diagram of a gain variation provided in the present application.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention.
Thus, the following detailed description of the embodiments of the present application, presented in the accompanying drawings, is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments in the present application without making any creative effort belong to the protection scope of the present application.
Furthermore, the terms "first," "second," and the like in the description and in the claims, as well as in the drawings, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in other sequences than those illustrated or described herein. Moreover, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
It should be noted that the features of the embodiments of the present application may be combined with each other without conflict. For better understanding of the objects, structure and function of the present invention, the variable gain amplifier provided in the present application will be described in further detail with reference to the accompanying drawings.
Referring to fig. 1, a schematic structural diagram of a variable gain amplifier according to a first embodiment of the present application is shown in fig. 1, where the variable gain amplifier includes: a variable gain unit 10 and at least one fixed gain unit 20. The embodiment takes 3 fixed gain units as an example for description, but the number of the fixed gain units in the solution of the present application is not limited to be only 3.
The input end of the variable gain unit 10 is used as the input end of the variable gain amplifier, and the control end of the variable gain unit 10 is used for receiving the input gain control signal to adjust the gain range; the output end of the variable gain unit 10 is connected to the input end of the first fixed gain unit, the output end of at least one fixed gain unit is sequentially cascaded with the input end of the next fixed gain unit, and the output end of the last fixed gain unit is used as the output end of the variable gain amplifier.
In this embodiment, the variable gain unit 10 includes a first differential input terminal V in And a second differential input terminal V ip The first differential input terminal V in And a second differential input terminal V ip Two differential input ends of the variable gain amplifier; a first differential output terminal of the variable gain unit 10 is connected to a first differential input terminal of a first fixed gain unit 21, and a second differential output terminal of the variable gain unit 10 is connected to a second differential input terminal of the first fixed gain unit; the first differential output terminal of each fixed gain unit is connected with the first differential input terminal of the next fixed gain unit, the first n-The second differential output end of each fixed gain unit in 1 fixed gain unit is connected with the second differential input end of the next fixed gain unit, and the first differential output end V of the last fixed gain unit on A first differential output terminal of the variable gain amplifier, and a second differential output terminal V of the last fixed gain unit op Is a second differential output of the variable gain amplifier.
In this embodiment, each fixed gain unit can realize a fixed gain of 12dB, and the control end of the variable gain unit 10 is configured to receive an input gain control signal, and is configured to adjust a dynamic gain range of the variable gain unit 10, so as to realize a gain compensation of 1dB and a dynamic gain range of 12 dB. For example, the present embodiment may employ a variable gain amplifier formed by cascading a variable gain unit 10 and three fixed gain units 20, which may achieve a gain in the range of 0-50 dB.
In an alternative embodiment, as shown in fig. 1, the variable gain amplifier further comprises: and a controllable voltage unit 30, wherein the controllable voltage unit 30 is connected with the control end of the variable gain unit 10.
In this embodiment, the controllable voltage unit 30 is configured to provide a gain control signal, and adjust the controllable voltage to linearly adjust the gain range of the variable gain unit.
The variable gain amplifier provided in the above embodiment includes: the input end of the variable gain unit is used as the input end of the variable gain amplifier, the control end of the variable gain unit is used for receiving an input gain control signal to adjust the gain range, the output end of the programmable gain unit is connected with the input end of the first fixed gain unit, the output end of the at least one fixed gain unit is sequentially connected with the input end of the next fixed gain unit in a cascade mode, and the output end of the last fixed gain unit is used as the output end of the variable gain amplifier. In the above embodiment, by controlling the gain range and the gain step of the variable gain unit, a variable gain amplifier with a wide gain range and a small gain step can be implemented, and the gain control accuracy of the variable gain amplifier is improved.
On the basis of the above embodiments, the present application also provides another embodiment of the variable gain amplifier. As shown in fig. 1, the variable gain amplifier further includes: and a numerical control adjusting unit 40.
At least one output terminal of the digitally controlled adjusting unit 40 is connected to a control terminal of at least one fixed gain unit 20, so as to control the gain function of the at least one fixed gain unit 20 to be turned on or off.
In this embodiment, the nc adjusting unit 40 receives a digital signal provided by an external system and performs encoding according to the digital signal, at least one output end of the nc adjusting unit 40 is connected to the control end of each fixed gain unit 20 to send an encoded signal to each fixed gain unit 20, and each fixed gain unit 20 controls the gain function to be turned on or turned off based on the corresponding encoded signal. When the numerical control adjusting unit 40 controls the fixed gain unit 20 to start the gain function, the gain range of the variable gain amplifier is increased; when the numerical control adjusting unit 40 controls the fixed gain unit 20 to close the gain function, the gain range of the variable gain amplifier is reduced, and the coarse adjustment of the gain of the whole variable gain amplifier is realized. Illustratively, the digitally controlled adjustment unit 40 may be an Encoder switch (Encoder) for receiving the digital signal and outputting a corresponding encoded signal to each of the fixed gain units 20.
In the above embodiment, the control end of the fixed gain unit is connected to the digital control adjustment unit to control the gain function of the fixed gain unit to be turned on or turned off, so as to implement coarse adjustment of the gain of the variable gain amplifier. The coarse adjustment of the fixed gain unit and the fine adjustment of the variable gain unit simplify the complexity of adjusting the gain of the variable gain amplifier, so that the precision of the gain adjustment of the variable gain amplifier is higher.
On the basis of the above embodiments, the present application also provides still another embodiment of the variable gain amplifier. Referring to fig. 2, a schematic structural diagram of a variable gain amplifier according to a second embodiment of the present application is shown in fig. 2, where the variable gain amplifier may further include: at least one filtering unit 50.
One filtering unit 50 is connected between the variable gain unit 10 and the first fixed gain unit, and the other filtering units 50 are connected between the adjacent two fixed gain units.
In this embodiment, the filtering units 50 are connected between the output end of the variable gain unit 10 and the input end of the first fixed gain unit, and between the output end and the input end of the adjacent fixed gain unit 20, and the filtering units 50 can eliminate the dc offset voltage generated by the variable gain unit 10 and the fixed gain unit 20, thereby ensuring the reliability of the variable gain amplifier. For example, the filtering unit 50 may include two filtering capacitors, one filtering capacitor in the filtering unit 50 is connected between the first differential output terminal of the variable gain unit 10 and the first differential input terminal of the first fixed gain unit, and the other filtering capacitor in the filtering unit 50 is connected between the second differential output terminal of the variable gain unit 10 and the second differential input terminal of the first fixed gain unit; similarly, one filter capacitor of the filter unit 50 is connected between the first differential output terminal and the first differential input terminal of the adjacent fixed gain unit 20, and the other filter capacitor of the filter unit 50 is connected between the second differential output terminal and the second differential input terminal of the adjacent fixed gain unit 20.
Based on the variable gain amplifier in the above embodiments, the present application also provides an embodiment of a variable gain unit. Referring to fig. 3, a schematic structural diagram of a variable gain unit provided in the present embodiment is shown in fig. 3, where the variable gain unit 10 includes: a transconductance unit 11 and a transimpedance unit 12.
The input end of the transconductance unit 11 serves as the input end of the variable gain unit 10, the output end of the transconductance unit 11 is connected to the input end of the transimpedance unit 12, and the output end of the transimpedance unit 12 serves as the output end of the variable gain unit 10.
In this embodiment, the transconductance unit 11 is a fixed transconductance unit, an amplification factor of the fixed transconductance unit is fixed and unchangeable, the transconductance unit 11 is configured to amplify an input voltage signal and convert the input voltage signal into a current signal, the transimpedance unit 12 is a variable transimpedance unit, the amplification factor is adjustable, the transimpedance unit 12 is configured to further amplify the current signal output by the transconductance unit 11 and convert the current signal into the voltage signal and output the voltage signal, the transimpedance unit 12 is a variable transimpedance unit, and a control end of the transimpedance unit 12 is used as a control end of the variable gain unit 12 to receive an input gain control signal.
For example, the transimpedance unit 12 may include a differential amplifier and two feedback networks, one feedback network is connected across a first differential input terminal and a first differential output terminal of the differential amplifier, the other feedback network is connected across a second differential input terminal and a second differential output terminal of the differential amplifier for forming negative feedback, and the feedback networks are used for adjusting the gain and the bandwidth of the variable gain unit 10.
It should be noted that the fixed gain unit 20 and the variable gain unit 10 have similar circuit structures, and also include a transconductance unit and a transimpedance unit, but the transimpedance unit of the fixed gain unit 20 is a fixed transimpedance unit.
Based on the variable gain unit in the above embodiments, the present application also provides some embodiments of a transconductance unit and a transimpedance unit. Referring to fig. 4, which is a schematic circuit diagram of a variable gain unit according to an embodiment of the present disclosure, as shown in fig. 4, the variable gain unit of the present embodiment adopts an improved Cherry-Hooper structure, wherein the transconductance unit 11 includes: a differential input pair transistor composed of a first transistor MOS1 and a second transistor MOS 2.
The gate of the first transistor MOS1 and the gate of the second transistor MOS2 are used as two differential input ends of the transconductance unit 11, the source of the first transistor MOS1 and the source of the second transistor MOS2 are grounded through a current source, and the drain of the first transistor MOS1 and the drain of the second transistor MOS2 are respectively connected to two input ends of the transimpedance unit 12.
Specifically, the gate of the first transistor MOS1 is used as the first differential input terminal V in The grid of the second transistor MOS2 is used as a second differential input end V ip The first transistor MOS1 and the second transistor MOS2 are used as differential input pair transistors, and are first gain stages of the variable gain unit, and are used for receiving an input voltage signal, amplifying the input voltage signal, and converting the amplified input voltage signal into a current signal for output.
In an alternative embodiment, the first transistor MOS1 and the second transistor MOS2 may be PMOS transistors.
As shown in fig. 4, the transimpedance unit 12 includes: a third transistor MOS3, a fourth transistor MOS4, a fifth transistor MOS5, a sixth transistor MOS6, a seventh transistor MOS7, an eighth transistor MOS8, a first feedback resistor RF1, and a second feedback resistor RF2.
The drain of the third transistor MOS3 and the drain of the sixth transistor MOS6 are used as two input terminals of the transimpedance unit 12, and the source of the third transistor MOS3 is connected to the source of the fourth transistor MOS4, the source of the fifth transistor MOS5, and the source of the sixth transistor MOS 6; the drain of the fourth transistor MOS4 is connected to the drain of the seventh transistor MOS7 and one end of the first feedback resistor RF1, and the gate of the seventh transistor MOS7 and the other end of the first feedback resistor RF1 are connected to one output end of the transconductance unit 12; the drain of the fifth transistor MOS5 is connected to the drain of the eighth transistor MOS8 and one end of the second feedback resistor RF2, and the gate of the eighth transistor MOS8 and the other end of the second feedback resistor RF2 are connected to the other output end of the transconductance unit 12; the grid electrode of the third transistor MOS3 is connected with the grid electrode of the fourth transistor MOS4, and the grid electrode of the fifth transistor MOS5 is connected with the grid electrode of the sixth transistor MOS 6; the source of the seventh transistor MOS7 and the source of the eighth transistor MOS8 are grounded through a current source, and the drain of the fourth transistor MOS4 and the drain of the fifth transistor MOS5 serve as two output terminals of the transimpedance unit 12.
Specifically, the gate of the seventh transistor MOS7 is connected to the first output terminal of the transconductance unit 11, the gate of the eighth transistor MOS8 is connected to the second output terminal of the transconductance unit 11, the seventh transistor MOS7 and the eighth transistor MOS8 also serve as a pair of differential input pair transistors, which serve as the second gain stage of the variable gain unit, for further amplifying the received current signal and converting the amplified current signal into a voltage signal, and the drain of the seventh transistor MOS7 serves as the first differential output terminal V on The drain of the eighth transistor MOS8 is used as the second differential output terminal V op 。
The third transistor MOS3 and the fourth transistor MOS4 form a pair of current mirrors, the drain current of the seventh transistor MOS7 is copied to the drain of the first transistor MOS1, and negative feedback from the output end of the second gain stage to the output end of the first gain stage is realized; the fifth transistor MOS5 and the fourth transistor MOS6 constitute a pair of current mirrors, and the drain current of the eighth transistor MOS8 is copied to the drain of the second transistor MOS2, thereby realizing negative feedback from the output terminal of the second gain stage to the output terminal of the first gain stage.
In an alternative embodiment, the third transistor MOS3, the fourth transistor MOS4, the fifth transistor MOS5, and the sixth transistor MOS6 are all NMOS transistors, and the seventh transistor MOS7 and the eighth transistor MOS8 are PMOS transistors.
In an alternative embodiment, the first feedback resistor RF1 and the second feedback resistor RF2 are adjustable resistors.
In this embodiment, the first feedback resistor RF1 and the second feedback resistor RF2 are equivalent voltage-controlled adjustable resistors of the transistor, specifically, the resistance of the transimpedance unit 122 is adjusted by changing the gate voltage of the transistor, that is, as shown in fig. 4, by adjusting Vctrl, the drain-source voltage Vds of the RF1 and RF2 transistors is far smaller than the gate-source voltage Vgs of the transistor, the transistor operates in a linear region and is resistive, and the resistance value is completely associated with the magnitude of Vctrl, therefore, the transistor can be equivalent to a voltage-controlled adjustable resistor, gain variation is realized, and other parts of the variable gain amplifier still require to operate in a saturation region. On this basis, the control terminals of the first feedback resistor RF1 and the second feedback resistor RF2 are configured to receive the input gain control signal, and adjust the resistance values of the first feedback resistor RF1 and the second feedback resistor R2 to adjust the output gain of the transimpedance unit 12.
In the existing scheme, an adjustable transconductance unit is adopted to adjust the amplification factor of the transconductance unit by adjusting current, so that the power consumption of a variable gain unit is larger, and because the current of the adjustable transconductance unit is continuously increased, a transistor in the adjustable transconductance unit possibly cannot work in a normal state, so that the working linearity of a variable gain amplifier designed on the basis of the adjustable transconductance unit is poorer; in addition, the circuit redundancy of the adjustable transconductance unit is high, so that the complexity of the designed variable gain amplifier is high. In the variable gain amplifier provided in the embodiment of the present application, the variable gain unit uses the fixed transconductance unit and the adjustable transimpedance unit as the variable gain unit, and the power consumption of the variable gain unit can be reduced by adjusting the amplification factor by adjusting the resistance value of the variable resistor in the transconductance unit, and the working linearity of the variable gain amplifier can be ensured to be better, and the fixed transconductance unit reduces the redundancy of the circuit, so that the complexity of the variable gain amplifier is lower.
For example, please refer to fig. 5, which is a schematic diagram of gain variation provided by the present application, as shown in fig. 5, an abscissa is frequency Hz, and an ordinate is gain dB, and as the frequency increases, the gain variation of the variable gain amplifier provided by the present embodiment is very flat, and the working linearity of the variable gain amplifier is better.
In an alternative embodiment, as shown in fig. 4, the transimpedance unit 12 further includes: a first capacitor C1 and a second capacitor C2; the first capacitor C1 is connected in parallel to both ends of the first feedback resistor RF1, and the second capacitor C2 is connected in parallel to both ends of the second feedback resistor RF2.
In this embodiment, the first capacitor C1 is connected in parallel to two ends of the first feedback resistor RF1, and the second capacitor C1 is connected in parallel to two ends of the second capacitor C2, so that the operating bandwidth of the variable gain amplifier can be adjusted, and the flatness of the gain can be adjusted.
In an alternative embodiment, as shown in fig. 4, the transimpedance unit 12 further includes: the circuit comprises a first resistor R1, a second resistor R2, a third resistor R3 and a fourth resistor R4; the first resistor R1 is connected in parallel to both ends of the source and the drain of the third transistor MOS3, the second resistor R2 is connected in parallel to both ends of the source and the drain of the fourth transistor MOS4, the third resistor R3 is connected in parallel to both ends of the source and the drain of the fifth transistor MOS5, and the fourth resistor R4 is connected in parallel to both ends of the source and the drain of the sixth transistor MOS 6.
In this embodiment, the first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4 limit the current in the circuit as much as possible without reducing the gain of the variable gain amplifier, thereby reducing the power consumption of the circuit.
Based on the above description of the circuit structure of the variable gain unit, the fixed gain unit of the embodiment of the present application may also adopt a similar circuit structure to the variable gain unit. The fixed gain unit of this embodiment adopts an improved Cherry-Hooper structure, the circuit structures of the fixed gain unit and the variable gain unit are basically similar, and detailed description is not given here, it should be noted that, in the fixed gain unit, the resistances of the first feedback resistor and the second feedback resistor in the transimpedance unit are not adjustable, and are fixed resistors.
Furthermore, in the fixed gain unit, a first controllable switch is connected between the current source and the ground on a line where the source of the first transistor MOS1 and the source of the second transistor MOS2 are grounded through the current source, a second controllable switch is connected between the current source and the ground on a line where the source of the seventh transistor MOS7 and the source of the eighth transistor MOS8 are grounded through the current source, the first controllable switch and the second controllable switch are controlled by the numerical control adjusting unit, the fixed gain unit turns off the gain function if the first controllable switch and the second controllable switch are opened, and the fixed gain unit turns on the gain function if the first controllable switch and the second controllable switch are closed.
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and shall be covered by the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (10)
1. A variable gain amplifier, comprising: a variable gain unit, at least one fixed gain unit;
the input end of the variable gain unit is used as the input end of the variable gain amplifier, and the control end of the variable gain unit is used for receiving an input gain control signal so as to adjust the gain range; the output end of the variable gain unit is connected with the input end of the first fixed gain unit, the output end of at least one fixed gain unit is sequentially cascaded with the input end of the next fixed gain unit, and the output end of the last fixed gain unit is used as the output end of the variable gain amplifier.
2. The variable gain amplifier of claim 1, wherein the variable gain amplifier further comprises: a numerical control adjusting unit;
at least one output end of the numerical control adjusting unit is connected with the control end of the at least one fixed gain unit to control the at least one fixed gain unit to start or close a gain function.
3. The variable gain amplifier of claim 1, wherein the variable gain amplifier further comprises: a controllable voltage unit;
the controllable voltage unit is connected with the control end of the variable gain unit.
4. The variable gain amplifier of claim 1, wherein the variable gain amplifier further comprises: at least one filtering unit;
one filter unit is connected between the variable gain unit and the first fixed gain unit, and the other filter units are connected between two adjacent fixed gain units.
5. The variable gain amplifier of claim 1 wherein said variable gain unit comprises: a transconductance unit and a transimpedance unit;
the input end of the transconductance unit is used as the input end of the variable gain unit, the output end of the transconductance unit is connected with the input end of the transimpedance unit, and the output end of the transimpedance unit is used as the output end of the variable gain unit.
6. The variable gain amplifier of claim 5, wherein said transconductance cell comprises: a differential input pair transistor consisting of a first transistor and a second transistor;
the grid electrode of the first transistor and the grid electrode of the second transistor are used as two differential input ends of the transconductance unit, the source electrode of the first transistor and the source electrode of the second transistor are grounded through a current source, and the drain electrode of the first transistor and the drain electrode of the second transistor are respectively connected with two input ends of the transimpedance unit.
7. The variable gain amplifier of claim 5, wherein the transimpedance unit comprises: the circuit comprises a third transistor, a fourth transistor, a fifth transistor, a sixth transistor, a seventh transistor, an eighth transistor, a first feedback resistor and a second feedback resistor;
a drain of the third transistor and a drain of the sixth transistor are used as two input ends of the transimpedance unit, and a source of the third transistor is connected with a source of the fourth transistor, a source of the fifth transistor and a source of the sixth transistor;
the drain electrode of the fourth transistor is connected with the drain electrode of the seventh transistor and one end of the first feedback resistor, and the grid electrode of the seventh transistor and the other end of the first feedback resistor are connected with one output end of the transconductance unit;
the drain of the fifth transistor is connected with the drain of the eighth transistor and one end of the second feedback resistor, and the gate of the eighth transistor and the other end of the second feedback resistor are connected with the other output end of the transconductance unit;
the grid electrode of the third transistor is connected with the grid electrode of the fourth transistor, and the grid electrode of the fifth transistor is connected with the grid electrode of the sixth transistor;
the source of the seventh transistor and the source of the eighth transistor are grounded through a current source, and the drain of the fourth transistor and the drain of the fifth transistor are used as two output ends of the transimpedance unit.
8. The variable gain amplifier of claim 7, wherein said transimpedance unit further comprises: a first capacitor and a second capacitor;
the first capacitor is connected in parallel to two ends of the first feedback resistor, and the second capacitor is connected in parallel to two ends of the second feedback resistor.
9. The variable gain amplifier of claim 7, wherein said transimpedance unit further comprises: the circuit comprises a first resistor, a second resistor, a third resistor and a fourth resistor;
the first resistor is connected in parallel across the source and the drain of the third transistor, the second resistor is connected in parallel across the source and the drain of the fourth transistor, the third resistor is connected in parallel across the source and the drain of the fifth transistor, and the fourth resistor is connected in parallel across the source and the drain of the sixth transistor.
10. The variable gain amplifier of claim 7 wherein said first feedback resistor and said second feedback resistor are adjustable resistors.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211022718.1A CN115395907A (en) | 2022-08-25 | 2022-08-25 | Variable gain amplifier |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202211022718.1A CN115395907A (en) | 2022-08-25 | 2022-08-25 | Variable gain amplifier |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116660835A (en) * | 2023-08-02 | 2023-08-29 | 太景科技(南京)有限公司 | Radar transmitting/receiving system and control method for radar transmitting/receiving system |
| CN116979918A (en) * | 2023-08-09 | 2023-10-31 | 北京无线电测量研究所 | Variable gain amplifier |
| CN117411445A (en) * | 2023-12-12 | 2024-01-16 | 成都明夷电子科技有限公司 | Broadband variable gain amplifier for optical receiver |
| CN116979918B (en) * | 2023-08-09 | 2024-06-21 | 北京无线电测量研究所 | Variable gain amplifier |
-
2022
- 2022-08-25 CN CN202211022718.1A patent/CN115395907A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116660835A (en) * | 2023-08-02 | 2023-08-29 | 太景科技(南京)有限公司 | Radar transmitting/receiving system and control method for radar transmitting/receiving system |
| CN116660835B (en) * | 2023-08-02 | 2023-10-17 | 太景科技(南京)有限公司 | Radar transmitting/receiving system and control method for radar transmitting/receiving system |
| CN116979918A (en) * | 2023-08-09 | 2023-10-31 | 北京无线电测量研究所 | Variable gain amplifier |
| CN116979918B (en) * | 2023-08-09 | 2024-06-21 | 北京无线电测量研究所 | Variable gain amplifier |
| CN117411445A (en) * | 2023-12-12 | 2024-01-16 | 成都明夷电子科技有限公司 | Broadband variable gain amplifier for optical receiver |
| CN117411445B (en) * | 2023-12-12 | 2024-03-12 | 成都明夷电子科技有限公司 | Broadband variable gain amplifier for optical receiver |
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