CN101350605B - Improved bipolar type variable gain amplifier with minimum gain control - Google Patents
Improved bipolar type variable gain amplifier with minimum gain control Download PDFInfo
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- CN101350605B CN101350605B CN2008101961180A CN200810196118A CN101350605B CN 101350605 B CN101350605 B CN 101350605B CN 2008101961180 A CN2008101961180 A CN 2008101961180A CN 200810196118 A CN200810196118 A CN 200810196118A CN 101350605 B CN101350605 B CN 101350605B
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Abstract
The present invention relates to a high linear variable gain amplifier with minimum gain control, based on a bipolar variable gain amplifier with a signal adding structure. In the high linear variable gain amplifier, a variable gain amplification unit (20) is not changed; a transconductance linearized unit (10) and a minimum gain control unit (30) are added; the variable gain amplifier adopts a transconductance enhancing circuit to improve the linearity of the amplifier. In order to control the minimum gain, the variable gain amplifier is provided with two parallel amplification branches: one is a variable gain unit which is used for providing the variable gain; the other is a minimum gain control circuit which is used for providing the fixed minimum gain; thus the variable gain amplifier can not generate the gain value difficult to be received, as a result of the error of the control voltage, improving the working stability of the circuit of the variable gain amplifier.
Description
Technical field
The present invention relates to the base band variable gain amplifier in a kind of radio-frequency transmitter, relate in particular to the implementation method of least gain control in the variable gain amplifier and the raising of variable gain amplifier neutral line degree.
Background technology
Variable gain amplifier (VGA) plays a part signal is amplified or decays in analog circuit, and it is widely used in disk and reads many aspects such as drive circuit, magnetic data storage system, electromagnetic couter, TV tuner; In the transceiver AFE (analog front end) of radio communication, also play crucial effects.
In the wireless receiver, (Automatic GainControl-AGC) realize by loop by automatic gain control for the function of real-time control signal size.It comprises signal amplitude detection circuit, error integrator circuit and variable-gain amplification circuit, and wherein, variable gain amplifier is the key modules of automatic gain control circuit loop.For under unlike signal power, the AGC loop all has identical transient response and definite loop settling time, and the gain of variable gain amplifier need change by index law.For bipolar process, because intrinsic base-emitter voltage of its transistor and the exponential relationship between the collector current, this circuit function ratio is easier to realize; For CMOS technology, be operated in the metal-oxide-semiconductor of saturation region, its channel current becomes quadratic relationship (long ditch device) with grid voltage, thereby needs the structure circuit, with the relation that realizes that gain index changes.
The variable gain amplifier of signal plus type structure is based on the circuit that bipolar process is realized, the variable gain amplifier of this structure is widely used with advantages such as its noiseproof feature are good, distortion is little, the circuit realization is simple.
Summary of the invention
Technical problem: the objective of the invention is to solve above-mentioned problems of the prior art, a kind of modified model variable gain amplifier based on signal plus type basic structure is provided.Utilize the structure of mutual conductance intensifier circuit (Gm-boosting), improved the linearity of variable gain amplifier; Simultaneously, through improving, make the maxgain value of variable gain amplifier of signal plus type structure have nothing to do with minimum gain value and gain-controlled voltage.
Technical scheme:, provide a kind of ambipolar variable gain amplifier that has least gain control according to purpose of the present invention.Based on the ambipolar variable gain amplifier of signal plus type structure, the variable gain amplifying unit remains unchanged, and has increased transconductance linearity unit and least gain control unit; Wherein, transconductance linearity unit first input end connects the input positive signal, the transconductance linearity unit second input termination input negative signal; The transconductance linearity unit first output termination variable gain amplifying unit first input end, the transconductance linearity unit second output termination variable gain amplifying unit, second input; The variable gain amplifying unit first output termination output positive signal line, the variable gain amplifying unit second output termination output negative signal line; The least gain control unit is connected across the two ends of transconductance linearity unit, variable gain amplifying unit, that is: least gain control unit first input end connects the input positive signal, the least gain control unit second input termination input negative signal, the least gain control unit first output termination output positive signal line, the least gain control unit second output termination input negative signal line.
Utilize the characteristics that mismatch is little, noiseproof feature is good of signal plus type structural circuit to constitute gain-changeable amplifier circuit; Simultaneously, the transconductance linearity circuit unit of increase has improved the linearity of variable gain amplifier effectively; The least gain control unit makes that the minimum gain value of this variable gain amplifier is controlled, has ensured the steady-working state of variable gain amplifier effectively.
Wherein, the first input end of transconductance linearity circuit unit is used for input radio frequency signal V
IN+, second input is used for input radio frequency signal V
IN-, the first input end of its first output termination variable gain amplifier unit, second input of its second output termination variable gain amplifier unit.First output of variable gain amplifier unit and second output are used for output signal V
OUT+And V
OUT-, connect first output and second output of least gain control unit simultaneously.The input of the first input end of least gain control unit and the second input termination transconductance linearity circuit unit, realization is in parallel with the variable gain amplifier unit.
The transconductance linearity circuit unit is used for improving the linearity of variable gain amplifier, and the variable gain amplifier unit is right after the transconductance linearity circuit output signal, under the control of gain-controlled voltage, realizes the Amplifier Gain adjustable function.Outstanding feature of the present invention is to use the least gain control unit that is connected across between the input and output, realizes the control of the least gain of variable gain amplifier.When the yield value of variable gain amplifier was very little, input signal was amplified to output via the least gain control unit, so that fixing minimum gain value to be provided.
In the transconductance linearity circuit unit, radio-frequency input signals V
IN+Be input to operational amplifier A
1Normal phase input end, radio-frequency input signals V
IN-Be input to operational amplifier A
2Normal phase input end.Operational amplifier A
1The base stage of transconductance linearity circuit the first transistor of output termination NPN type, operational amplifier A
1Negative-phase input connect the emitter of transconductance linearity circuit the first transistor, the emitter of transconductance linearity circuit the first transistor connects the emitter-base bandgap grading feedback resistance simultaneously. symmetrical therewith is operational amplifier A
2The base stage of output termination transconductance linearity circuit transistor seconds, operational amplifier A
2Negative-phase input connect the emitter of transconductance linearity circuit transistor seconds, the emitter of transconductance linearity circuit transistor seconds 102 connects the emitter-base bandgap grading feedback resistance through the transconductance linearity circuit simultaneously, voltage signal changes current signal into, input signal VIN+ changes Iin+ into, is input to the first input end B1 of variable gain amplifier unit; Input signal VIN-changes Iin-into, is input to the second input B2 of variable gain amplifier unit.
The variable gain amplifier unit comprises the first transistor; Transistor seconds; The 3rd transistor; The 4th transistor; And as first resistor and second resistor of load resistance; Employing helps reducing adaptive structure of suing for peace with four pipe signals of the symmetry that improves noiseproof feature, that is: the emitter of the first transistor, transistor seconds is connected, the 3rd transistor, the 4th transistorized emitter are connected, and transistor seconds, the 4th transistorized base stage are connected and meet V
AGC+, the first transistor, the 3rd transistorized base stage are connected and meet V
AGC-
In the least gain control unit, the collector electrode of least gain control the first transistor meets the signal output part Vout+ of variable gain amplifier, its base stage meets the signal input part VIN+ of transconductance linearity unit, symmetrical with it is, the collector electrode of least gain control transistor seconds meets the signal output part Vout-of variable gain amplifier, and these two transistorized emitters of signal input part VIN-. that its base stage connects the transconductance linearity unit are connected to the emitter-base bandgap grading feedback resistance of big resistance respectively.
Beneficial effect: the beneficial effect of this modified model variable gain amplifier is by adopting the circuit of mutual conductance enhancing structure, to have significantly improved the linearity of variable gain amplifier.Simultaneously, by adopting the least gain control unit circuit that is in parallel with the variable gain unit, make the minimum gain amplifier of variable gain amplifier be guaranteed.
Description of drawings
Fig. 1 is a variable gain amplifier block diagram of the present invention.
Fig. 2 is the transconductance linearity unit of variable gain amplifier of the present invention.
Fig. 3 is the variable gain amplifying unit of variable gain amplifier of the present invention.
Fig. 4 is the least gain control unit of variable gain amplifier of the present invention.
Embodiment
Below in conjunction with accompanying drawing and embodiment the present invention is described in further detail.
Referring to Fig. 1, Fig. 1 is the block diagram of modified model variable gain amplifier of the present invention.Modified model variable gain amplifier of the present invention comprises three unit: transconductance linearity circuit unit 10, variable gain amplifier unit 20 and least gain control unit 30.Wherein, the first input end A1 of transconductance linearity circuit unit 10 is used for input radio frequency signal V
IN+, the second input A2 is used for input radio frequency signal V
IN-, its first output terminals A 3 meets the first input end B1 of variable gain amplifier unit, and its second output terminals A 4 meets the second input B2 of variable gain amplifier unit.The first output B3 of variable gain amplifier unit and the second output B4 are used for output signal V
OUT+And V
OUT-, meet the first output C1 and the second output C2 of least gain control unit simultaneously.The first input end C3 of least gain control unit and the second input C4 meet the input A1 and the A2 of transconductance linearity circuit unit, and realization is in parallel with the variable gain amplifier unit.
Transconductance linearity circuit unit 10 is used for improving the linearity of variable gain amplifier, and variable gain amplifier unit 20 is right after the transconductance linearity circuit output signal, under the control of gain-controlled voltage, realizes the Amplifier Gain adjustable function.Outstanding feature of the present invention is to use the least gain control unit 30 that is connected across between the input and output, realizes the control of the least gain of variable gain amplifier.When the yield value of variable gain amplifier was very little, input signal was amplified to output via the least gain control unit, so that fixing minimum gain value to be provided.
In the transconductance linearity circuit unit, radio-frequency input signals VIN+ is input to operational amplifier A
1Normal phase input end, radio-frequency input signals VIN-is input to operational amplifier A
2Normal phase input end.Operational amplifier A
1The base stage of transconductance linearity circuit the first transistor 101 of output termination NPN type, operational amplifier A
1Negative-phase input connect the emitter of transconductance linearity circuit the first transistor 101, simultaneously the emitter of transconductance linearity circuit the first transistor 101 connect emitter-base bandgap grading feedback resistance 103. symmetrical therewith be operational amplifier A
2The base stage of output termination transconductance linearity circuit transistor seconds 102, operational amplifier A
2Negative-phase input connect the emitter of transconductance linearity circuit transistor seconds 102, the emitter of transconductance linearity circuit transistor seconds 102 connects emitter-base bandgap grading feedback resistance 104. through the transconductance linearity circuit simultaneously, voltage signal changes current signal into, input signal VIN+ changes Iin+ into, is input to the first input end B1 of variable gain amplifier unit; Input signal VIN-changes Iin-into, is input to the second input B2 of variable gain amplifier unit.
The variable gain amplifier unit is a basic variable gain amplifier structure based on signal plus type structure, and variable gain amplifier unit 20 comprises the first transistor 201; Transistor seconds 202; The 3rd transistor 203; The 4th transistor 204; And as first resistor 207 and second resistor 208 of load resistance; Employing helps reducing adaptive structure of suing for peace with four pipe signals of the symmetry that improves noiseproof feature, that is: the emitter of the first transistor 201, transistor seconds 202 is connected, the 3rd transistor 203, the 4th transistor 204) emitter be connected, the base stage of transistor seconds 202, the 4th transistor (204) is connected, and meets V
AGc+, the first transistor 201, the 3rd transistor 203) base stage be connected, and meet V
AGC-
In the least gain control unit, the collector electrode of least gain control the first transistor 301 meets the signal output part Vout+ of variable gain amplifier, its base stage meets the signal input part VIN+ of transconductance linearity unit, symmetrical with it is, the collector electrode of least gain control transistor seconds 302 meets the signal output part Vout-of variable gain amplifier, and these two transistorized emitters of signal input part VIN-. that its base stage connects the transconductance linearity unit are connected to the emitter-base bandgap grading feedback resistance 303,304 of big resistance respectively.
Modified model variable gain amplifier of the present invention at first adopts mutual conductance to strengthen structural circuit, use by operational amplifier A 1, A2, the gm value of transconductance linearity circuit the first transistor 101, transconductance linearity circuit transistor seconds 102 is risen to original A doubly, again in conjunction with emitter-base bandgap grading feedback resistance 103,104, realize the linearisation of mutual conductance, thereby improved the linearity of variable gain amplifier.In addition, this follow-on variable gain amplifier has been realized the controllability of variable gain amplifier minimum gain value by least gain control unit in parallel on the variable gain unit.Under the control at gain-controlled voltage, when the gain of variable gain unit was very little, input signal was amplified to output via the least gain control unit, thereby fixing minimum gain value can be provided.
Claims (3)
1. one kind has the highly linear variable gain amplifier that least gain is controlled, it is characterized in that: based on the ambipolar variable gain amplifier of signal plus type structure, variable gain amplifying unit (20) remains unchanged, and has increased transconductance linearity unit (10) and least gain control unit (30); Wherein, transconductance linearity unit first input end (A1) meets input positive signal (V
IN+), transconductance linearity unit second input (A2) meets input negative signal (V
IN-); Transconductance linearity unit first output (A3) connects variable gain amplifying unit first input end (B1), and transconductance linearity unit second output (A4) connects variable gain amplifying unit second input (B2); Variable gain amplifying unit first output (B3) meets output positive signal line (V
OUT+), variable gain amplifying unit second output (B4) meets output negative signal line (V
OUT-); Least gain control unit (30) is connected across the two ends of transconductance linearity unit (10), variable gain amplifying unit (20), that is: least gain control unit first input end (C3) meets input positive signal (V
IN+), least gain control unit second input (C4) meets input negative signal (V
IN-), least gain control unit first output (C1) meets output positive signal line (V
OUT+), least gain control unit second output (C2) meets output negative signal line (V
OUT-).
2. the highly linear variable gain amplifier that has least gain control as claimed in claim 1 is characterized in that described variable gain amplifying unit (20) comprises the first transistor (201); Transistor seconds (202); The 3rd transistor (203); The 4th transistor (204); And as first resistor (207) and second resistor (208) of load resistance; Employing helps reducing adaptive structure of suing for peace with four pipe signals of the symmetry that improves noiseproof feature, that is: the emitter of the first transistor (201), transistor seconds (202) is connected, the emitter of the 3rd transistor (203), the 4th transistor (204) is connected, the base stage of transistor seconds (202), the 4th transistor (204) is connected, and meets AGC (automatic gain control) voltage positive pole (V
AGC+), the base stage of the first transistor (201), the 3rd transistor (203) is connected, and meets AGC (automatic gain control) voltage negative pole (V
AGC-).
3. the highly linear variable gain amplifier that has least gain control as claimed in claim 1 is characterized in that, in the least gain control unit, the collector electrode of least gain control the first transistor (301) meets the output positive signal line (V of variable gain amplifier
OUT+), its base stage meets the input positive signal (V of transconductance linearity unit
IN+), symmetrical with it is that the collector electrode of least gain control transistor seconds (302) meets the output negative signal line (V of variable gain amplifier
OUT-), its base stage meets the input negative signal (V of transconductance linearity unit
IN-). these two transistorized emitters are connected to the emitter-base bandgap grading feedback resistance (303,304) of big resistance respectively.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2008101961180A CN101350605B (en) | 2008-09-12 | 2008-09-12 | Improved bipolar type variable gain amplifier with minimum gain control |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2008101961180A CN101350605B (en) | 2008-09-12 | 2008-09-12 | Improved bipolar type variable gain amplifier with minimum gain control |
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| Publication Number | Publication Date |
|---|---|
| CN101350605A CN101350605A (en) | 2009-01-21 |
| CN101350605B true CN101350605B (en) | 2011-09-28 |
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|---|---|---|---|
| CN2008101961180A Expired - Fee Related CN101350605B (en) | 2008-09-12 | 2008-09-12 | Improved bipolar type variable gain amplifier with minimum gain control |
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Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102064773B (en) * | 2009-11-16 | 2013-09-11 | 杭州士兰微电子股份有限公司 | Adjustable gain low noise amplifier |
| CN102064778B (en) * | 2009-11-16 | 2013-04-10 | 杭州士兰微电子股份有限公司 | Gain adjustable amplifier |
| CN101995900B (en) * | 2010-10-13 | 2014-07-02 | 苏州科山微电子科技有限公司 | Gradient voltage generator used for continuous variable gain amplifier |
| JP2012169898A (en) * | 2011-02-15 | 2012-09-06 | Lapis Semiconductor Co Ltd | Variable gain amplification circuit |
| EP3329590A4 (en) * | 2015-07-29 | 2019-07-03 | Macom Connectivity Solutions, LLC | Programmable gain amplifier with controlled gain steps |
| CN113424442B (en) * | 2019-02-27 | 2022-05-31 | 华为技术有限公司 | Variable gain amplifier |
| CN114221624B (en) * | 2021-11-11 | 2024-03-26 | 华南理工大学 | Low-noise amplifier and chip |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1998033272A1 (en) * | 1997-01-27 | 1998-07-30 | Qualcomm Incorporated | High dynamic range variable gain amplifier |
| US20050057305A1 (en) * | 2003-09-15 | 2005-03-17 | Krone Andrew W. | Radio frequency low noise amplifier with automatic gain control |
| CN101013911A (en) * | 2007-02-13 | 2007-08-08 | 鼎芯通讯（上海）有限公司 | Control circuit of radio-frequency variable gain amplifier and gain control method |
-
2008
- 2008-09-12 CN CN2008101961180A patent/CN101350605B/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1998033272A1 (en) * | 1997-01-27 | 1998-07-30 | Qualcomm Incorporated | High dynamic range variable gain amplifier |
| US20050057305A1 (en) * | 2003-09-15 | 2005-03-17 | Krone Andrew W. | Radio frequency low noise amplifier with automatic gain control |
| CN101013911A (en) * | 2007-02-13 | 2007-08-08 | 鼎芯通讯（上海）有限公司 | Control circuit of radio-frequency variable gain amplifier and gain control method |
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|---|---|
| CN101350605A (en) | 2009-01-21 |
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Effective date of registration: 20081226 Address after: No. four arch 2, Nanjing City, Jiangsu Province Applicant after: Southeast University Co-applicant after: WUXI SI-POWER MICRO-ELECTRONICS Co., LTD. Address before: No. four arch 2, Nanjing City, Jiangsu Province Applicant before: Southeast University |
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| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20110928 Termination date: 20160912 |