CN103780208A - Amplifier circuit - Google Patents
Amplifier circuit Download PDFInfo
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- CN103780208A CN103780208A CN201410024679.8A CN201410024679A CN103780208A CN 103780208 A CN103780208 A CN 103780208A CN 201410024679 A CN201410024679 A CN 201410024679A CN 103780208 A CN103780208 A CN 103780208A
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- triode
- emitter
- base stage
- electrode
- resistance
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Abstract
The invention discloses an amplifier circuit which comprises an input transconductance circuit, an output circuit and a distortion offset feedback loop, wherein the distortion offset feedback loop comprises a third triode, a fourth triode, a fifth triode, a sixth triode, a first resistor and a second resistor, wherein a base electrode of the third triode is connected with that of the fourth triode; an emitting electrode of the third triode is connected with that of the fourth triode; the emitting electrode of the fourth electrode is connected with a bias voltage; a base electrode of the second triode is respectively connected with a collecting electrode of the second triode and a base electrode of the third triode; a base electrode of the fifth triode is connected with that of the six triode; the collecting electrode of the fifth triode is respectively connected with a base plate of the fifth triode and a collecting electrode of the fourth triode; an emitting electrode of the fifth triode is grounded by virtue of the first resistor; a collecting electrode of the six triode is connected to the emitting electrode of the second triode; an emitting electrode of the sixth triode is grounded by virtue of the second resistor. According to the amplifier circuit, a distortion offset technology is adopted, so that the OIP3 output performance is improved.
Description
Technical field
The invention belongs to electric and electronic technical field, particularly a kind of amplifier circuit.
Background technology
In Modern Communication System, amplifier circuit is widely used, and is mainly positioned at receiver end in transceiver system, is one of most important module in receiver, and its linearity is by the linearity index of the whole receiver system of impact.Linearity index, generally with OIP3 definition, represents the third order distortion characteristic of circuit.Current most of receiver system generally all requires the OIP3 of amplifier more than 40dBm.
A kind of existing amplifier circuit figure, operational amplifier OPA and emitter resistance R as shown in Figure 1
sand triode Q
1form input transconductance circuit, input voltage has been converted to electric current, transistor Q
2for common base output circuit, provide larger output resistance, to guarantee the performance of output.
Adopt the amplifier circuit structural circuit shown in Fig. 1, show through Multi simulation running and test, in 200MHz frequency, its OIP3 be difficult to reach 42dBm with, in the stricter system of performance requirement, cannot meet application requirements.
Amplifier distortion principle analysis figure as shown in Figure 2, Q
2for the triode of output stage, the parasitic diode D of collector-base
1and the parasitic diode D of collector electrode-substrate
2be Q
2in parasitic diode, output voltage v
outat diode D
1and D
2negative electrode has produced distorted current i
m1and i
m2.Output current can be expressed as like this:
i
out=i
in+i
m1+i
m2
Due to distorted current i
m1and i
m2existence, make to export OIP3 and be difficult to reach very high level.
Summary of the invention
The technical problem existing in order to solve above-mentioned background technology, the present invention aims to provide a kind of amplifier circuit, thereby improves the performance of output OIP3.
In order to realize above-mentioned technical purpose, technical scheme of the present invention is:
A kind of amplifier circuit, comprise input transconductance circuit and output circuit, described input transconductance circuit comprises operational amplifier, emitter resistance and the first triode, the end of oppisite phase of operational amplifier connects the emitter of the first triode, the emitter of the first triode ground connection after emitter resistance, the output of the base stage concatenation operation amplifier of the first triode, the in-phase end of operational amplifier is as the input of this amplifier circuit, described output circuit comprises the second triode, the emitter of the second triode connects the collector electrode of the first triode, the collector electrode of the second triode is as the output of this amplifier circuit.This amplifier circuit also comprises distortion cancellation feedback control loop, described distortion cancellation feedback control loop comprises the 3rd triode, the 4th triode, the 5th triode, the 6th triode, the first resistance and the second resistance, the base stage of the 3rd triode connects the base stage of the 4th triode, the emitter of the 3rd triode connects the emitter of the 4th triode, the emitter access bias voltage of the 4th triode, the base stage of the second triode connects respectively the base stage of collector electrode and the 3rd triode of the 3rd triode, the base stage of the 5th triode connects the base stage of the 6th triode, the collector electrode of the 5th triode connects respectively the base stage of the 5th triode and the collector electrode of the 4th triode, the emitter of the 5th triode is ground connection after the first resistance, the collector electrode of the 6th triode connects the emitter of the second triode, the emitter of the 6th triode is ground connection after the second resistance.
The beneficial effect that adopts technique scheme to bring is:
The present invention adopts distortion cancellation technology, by extracting distortion component, feeds back in output signal, balances out original distortion component, has greatly improved the OIP3 performance of amplifier.Emulation and test result show, than the amplifier circuit of original ordinary construction, in the present invention, adopt the OIP3 of amplifier of distortion cancellation technology more than 200MHz frequency place brings up to 47dBm by 42dBm, substantially met the index request of most systems.
Accompanying drawing explanation
Fig. 1 is a kind of existing amplifier circuit figure;
Fig. 2 is amplifier distortion principle analysis figure;
Fig. 3 is a kind of amplifier circuit figure of the present invention.
Main symbol description: Q1～Q6 in figure: the first～six triode; R1: the first resistance; R2: the second resistance; RS: emitter resistance; OPA: operational amplifier, wherein Q3, Q4 are pnp type triodes, Q1, Q2, Q5, Q6 are npn type triodes.
Embodiment
Below with reference to accompanying drawing, technical scheme of the present invention is elaborated.
Circuit diagram of the present invention as shown in Figure 3, a kind of amplifier circuit, comprises input transconductance circuit and output circuit, and described input transconductance circuit comprises operational amplifier OPA, emitter resistance R
swith the first triode Q
1, the end of oppisite phase of operational amplifier OPA connects the first triode Q
1emitter, the first triode Q
1emitter through emitter resistance R
srear ground connection, the first triode Q
1the output of base stage concatenation operation amplifier OPA, the in-phase end of operational amplifier OPA is as the input of this amplifier circuit, described output circuit comprises the second triode Q
2, the second triode Q
2emitter connect the first triode Q
1collector electrode, the second triode Q
2collector electrode as the output of this amplifier circuit.This amplifier circuit also comprises distortion cancellation feedback control loop, and described distortion cancellation feedback control loop comprises the 3rd triode Q
3, the 4th triode Q
4, the 5th triode Q
5, the 6th triode Q
6, the first resistance R
1with the second resistance R
2, the 3rd triode Q
3base stage connect the 4th triode Q
4base stage, the 3rd triode Q
3emitter connect the 4th triode Q
4emitter, the 4th triode Q
4emitter access bias voltage V
d, the second triode Q
2base stage connect respectively the 3rd triode Q
3collector electrode and the 3rd triode Q
3base stage, the 5th triode Q
5base stage connect the 6th triode Q
6base stage, the 5th triode Q
5collector electrode connect respectively the 5th triode Q
5base stage and the 4th triode Q
4collector electrode, the 5th triode Q
5emitter through the first resistance R
1rear ground connection, the 6th triode Q
6collector electrode connect the second triode Q
2emitter, the 6th triode Q
6emitter through the second resistance R
2rear ground connection.
Output voltage v in the present invention
outat parasitic diode D
1and D
2negative electrode produce distorted current i
m1and i
m2there is identical characteristic and phase place, can suppose i
m2=α i
m1, wherein α is fixing proportionality coefficient, general relevant with operational characteristic.Q
3extract distorted current i
m1, Q
3, Q
4, Q
5, Q
6form image current mirror, Q
5and Q
6current mirror proportionality coefficient is 1:n, like this at Q
6collector electrode just produced size for n i
m1distorted current be injected into Q
2, output current can be expressed as:
i
out=i
in+i
m1+i
m2-n?i
m1=i
in+(1+α-n)i
m1
From above formula, adopt amplifier circuit of the present invention, make n=1+ α as long as choose suitable n value, can realize i
out=i
in, like this, undistorted current component in output current, output current is directly directly proportional to input current, and this is to keep the prerequisite condition of high linearity.
Above embodiment only, for explanation technological thought of the present invention, can not limit protection scope of the present invention with this, every technological thought proposing according to the present invention, and any change of doing on technical scheme basis, within all falling into protection range of the present invention.
Claims (1)
1. an amplifier circuit, comprise input transconductance circuit and output circuit, described input transconductance circuit comprises operational amplifier, emitter resistance and the first triode, the end of oppisite phase of operational amplifier connects the emitter of the first triode, the emitter of the first triode ground connection after emitter resistance, the output of the base stage concatenation operation amplifier of the first triode, the in-phase end of operational amplifier is as the input of this amplifier circuit, described output circuit comprises the second triode, the emitter of the second triode connects the collector electrode of the first triode, the collector electrode of the second triode is as the output of this amplifier circuit, it is characterized in that: this amplifier circuit also comprises distortion cancellation feedback control loop, described distortion cancellation feedback control loop comprises the 3rd triode, the 4th triode, the 5th triode, the 6th triode, the first resistance and the second resistance, the base stage of the 3rd triode connects the base stage of the 4th triode, the emitter of the 3rd triode connects the emitter of the 4th triode, the emitter access bias voltage of the 4th triode, the base stage of the second triode connects respectively the base stage of collector electrode and the 3rd triode of the 3rd triode, the base stage of the 5th triode connects the base stage of the 6th triode, the collector electrode of the 5th triode connects respectively the base stage of the 5th triode and the collector electrode of the 4th triode, the emitter of the 5th triode is ground connection after the first resistance, the collector electrode of the 6th triode connects the emitter of the second triode, the emitter of the 6th triode is ground connection after the second resistance.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410024679.8A CN103780208B (en) | 2014-01-21 | 2014-01-21 | Amplifier circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410024679.8A CN103780208B (en) | 2014-01-21 | 2014-01-21 | Amplifier circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN103780208A true CN103780208A (en) | 2014-05-07 |
| CN103780208B CN103780208B (en) | 2017-01-04 |
Family
ID=50572125
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410024679.8A Expired - Fee Related CN103780208B (en) | 2014-01-21 | 2014-01-21 | Amplifier circuit |
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| Country | Link |
|---|---|
| CN (1) | CN103780208B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104038160A (en) * | 2014-06-17 | 2014-09-10 | 南京美辰微电子有限公司 | Distortion offset bias circuit for improving amplifier linearity and method for improving linearity |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH07326978A (en) * | 1994-05-31 | 1995-12-12 | Toshiba Ave Corp | Automatic gain control loop circuit |
| US7116172B2 (en) * | 2004-11-03 | 2006-10-03 | Texas Instruments Incorporated | High-swing folded cascode having a novel gain-boost amplifier |
| CN101022266A (en) * | 2006-09-28 | 2007-08-22 | 威盛电子股份有限公司 | Power amplifier |
| US8432226B1 (en) * | 2010-07-08 | 2013-04-30 | Adtran, Inc. | Amplifier circuits and methods for cancelling Miller capacitance |
-
2014
- 2014-01-21 CN CN201410024679.8A patent/CN103780208B/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH07326978A (en) * | 1994-05-31 | 1995-12-12 | Toshiba Ave Corp | Automatic gain control loop circuit |
| US7116172B2 (en) * | 2004-11-03 | 2006-10-03 | Texas Instruments Incorporated | High-swing folded cascode having a novel gain-boost amplifier |
| CN101022266A (en) * | 2006-09-28 | 2007-08-22 | 威盛电子股份有限公司 | Power amplifier |
| US8432226B1 (en) * | 2010-07-08 | 2013-04-30 | Adtran, Inc. | Amplifier circuits and methods for cancelling Miller capacitance |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104038160A (en) * | 2014-06-17 | 2014-09-10 | 南京美辰微电子有限公司 | Distortion offset bias circuit for improving amplifier linearity and method for improving linearity |
| CN104038160B (en) * | 2014-06-17 | 2018-06-15 | 南京美辰微电子有限公司 | It improves the distortion cancellation biasing circuit of Amplifier linearity and improves Linearity Method |
Also Published As
| Publication number | Publication date |
|---|---|
| CN103780208B (en) | 2017-01-04 |
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Granted publication date: 20170104 Termination date: 20170121 |
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