CN104378073A - Operational amplifier - Google Patents
Operational amplifier Download PDFInfo
- Publication number
- CN104378073A CN104378073A CN201410626421.5A CN201410626421A CN104378073A CN 104378073 A CN104378073 A CN 104378073A CN 201410626421 A CN201410626421 A CN 201410626421A CN 104378073 A CN104378073 A CN 104378073A
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- Prior art keywords
- circuit
- input
- operational amplifier
- output
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Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
- H03F1/30—Modifications of amplifiers to reduce influence of variations of temperature or supply voltage or other physical parameters
- H03F1/301—Modifications of amplifiers to reduce influence of variations of temperature or supply voltage or other physical parameters in MOSFET amplifiers
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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
- H03F3/45—Differential amplifiers
- H03F3/45071—Differential amplifiers with semiconductor devices only
- H03F3/45076—Differential amplifiers with semiconductor devices only characterised by the way of implementation of the active amplifying circuit in the differential amplifier
- H03F3/45475—Differential amplifiers with semiconductor devices only characterised by the way of implementation of the active amplifying circuit in the differential amplifier using IC blocks as the active amplifying circuit
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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
- H03F3/45—Differential amplifiers
- H03F3/45071—Differential amplifiers with semiconductor devices only
- H03F3/45479—Differential amplifiers with semiconductor devices only characterised by the way of common mode signal rejection
- H03F3/45928—Differential amplifiers with semiconductor devices only characterised by the way of common mode signal rejection using IC blocks as the active amplifying circuit
- H03F3/45968—Differential amplifiers with semiconductor devices only characterised by the way of common mode signal rejection using IC blocks as the active amplifying circuit by offset reduction
- H03F3/45973—Differential amplifiers with semiconductor devices only characterised by the way of common mode signal rejection using IC blocks as the active amplifying circuit by offset reduction by using a feedback circuit
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F2201/00—Indexing scheme relating to details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements covered by H03F1/00
- H03F2201/32—Indexing scheme relating to modifications of amplifiers to reduce non-linear distortion
- H03F2201/3215—To increase the output power or efficiency
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F2203/00—Indexing scheme relating to amplifiers with only discharge tubes or only semiconductor devices as amplifying elements covered by H03F3/00
- H03F2203/45—Indexing scheme relating to differential amplifiers
- H03F2203/45118—At least one reactive element being added to at least one feedback circuit of a dif amp
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Amplifiers (AREA)
Abstract
The invention discloses an operational amplifier which comprises an input stage circuit, an output stage circuit and a difference mode feedback circuit. By use of the operational amplifier, on the premise of not increasing the circuit complexity, the offset voltage of the operational amplifier is eliminated by additionally arranging the difference mode feedback circuit, and the problem that quiescent operating points of an existing operational amplifier drift due to work temperature changes is solved. An input tube of an asymmetric structure is used in the input stage circuit, so that voltage gains of a feedback loop are improved, and meanwhile mismatching errors caused by a traditional input tube of a symmetric structure are avoided.
Description
Technical field
The present invention relates to a kind of operational amplifier, particularly a kind of for driving the operational amplifier of the capable load of the electric capacity of such as liquid crystal indicator.
Background technology
Traditionally, bipolar transistor is in most of the cases used to carry out construction operation amplifier.But, along with coexisting to MOS circuit and bipolar transistor and the continuous requirement of low power run, use the situation of MOS transistor construction operation amplifier more common at present.When with MOS transistor construction operation amplifier, by the mode characteristic utilizing MOS transistor intrinsic, the circuit structure of operational amplifier and the different of employing bipolar transistor, the example of this kind of operational amplifier comprises the amplifier using electronics handoff functionality.
Tft liquid crystal display (TFT LCD) driver LSI is one of application using MOS transistor construction operation amplifier.This lcd driver LSI comprises multiple operational amplifier with voltage follower configuration as output buffer amplifier and the GTG power supply for gamma correction, requires only there is little difference in the offset voltage of lcd driver LSI in described multiple operational amplifier.Therefore, the MOS operational amplifier with minimum offset voltage is required in the art.
In the unity gain operational amplifier of traditional closed-loop structure, two-stage unit gain discharge circuit is mainly through increasing dual-sampling circuit on the output, improving the symmetry of input stage metal-oxide-semiconductor and using wave chopping technology to eliminate the offset voltage of amplifier.As shown in Figure 1, this discharge circuit comprises biasing circuit, input stage circuit and output-stage circuit three part.Input stage employs the differential input structure be made up of metal-oxide-semiconductor M1, M2, M5.Output-stage circuit is made up of M6, M7 and electric capacity Cc and CL, and the signal of difference output is amplified in the second level as amplifier, and electric capacity Cc is miller capacitance, regulates the stability of amplifier.This circuit also comprises an image current mirror be made up of M3 and M4.But, increase dual-sampling circuit and use wave chopping technology to both increase the complexity of circuit; Due to technique, input and also cannot eliminate completely the mismatch problems of pipe; Wave chopping technology needs the clock signal of extra circuit and certain frequency to realize.
Summary of the invention
Goal of the invention: for problems of the prior art, the present invention proposes a kind of operational amplifier, solves the metal-oxide-semiconductor mismatch that manufacture technics causes, and then affects the problem of offset voltage.
Technical scheme: a kind of operational amplifier, comprising:
Input stage circuit, this input stage circuit comprises mirror image circuit, Differential input circuit A, Differential input circuit B, to provide the biasing circuit A of bias current for Differential input circuit A and provide the biasing circuit B of bias current for Differential input circuit B;
Output-stage circuit, this output-stage circuit is provided input voltage by the output B of mirror image circuit and is formed output voltage;
And differential mode feedback circuit, this differential mode feedback circuit is connected with output-stage circuit, biasing circuit A and biasing circuit B, for detecting the difference of input voltage and output voltage, final feedback signal eliminates offset voltage by two biasing circuits in control inputs level circuit respectively.
Described Differential input circuit A and Differential input circuit B is set to the dissymmetrical structure improving feedback voltage gain respectively.
The mutual conductance of two input pipes in described Differential input circuit A is asymmetric, and the mutual conductance of the metal-oxide-semiconductor be wherein connected with mirror image circuit output terminals A is greater than the mutual conductance of the metal-oxide-semiconductor be connected with mirror image circuit output B; The mutual conductance of two input pipes in described Differential input circuit B is also asymmetric, and the mutual conductance of the metal-oxide-semiconductor be wherein connected with mirror image circuit output B is greater than the mutual conductance of the metal-oxide-semiconductor be connected with mirror image circuit output terminals A.
Described Differential input circuit A and Differential input circuit B are that the identical input of parallel connection is to pipe.
Described input is different to the size of the metal-oxide-semiconductor of two in pipe.
The input of described Differential input circuit A and Differential input circuit B is cross interconnected with mirror image circuit respectively to pipe.
Beneficial effect: compared with prior art, tool of the present invention has the following advantages: under the prerequisite not increasing circuit complexity, eliminating offset voltage by increasing a differential mode feedback circuit, solving the quiescent point drifting problem that operational amplifier produces due to temperature change; By using the input pipe of dissymmetrical structure in input stage circuit, improve feedback control loop voltage gain, avoiding the mismatch error that conventional symmetrical structure input pipe is formed simultaneously.
Accompanying drawing explanation
Fig. 1 is the circuit diagram of a kind of two-stage unit gain discharge circuit of prior art;
Fig. 2 is the structural representation of operational amplifier of the present invention;
Fig. 3 is the circuit diagram of input stage circuit in operational amplifier of the present invention;
Fig. 4 is the circuit diagram of differential mode feedback circuit and output-stage circuit in operational amplifier of the present invention.
Embodiment
Below in conjunction with the drawings and specific embodiments, illustrate the present invention further, these embodiments should be understood only be not used in for illustration of the present invention and limit the scope of the invention, after having read the present invention, those skilled in the art have all fallen within the application's claims limited range to various equivalents of the present invention.
Operational amplifier as shown in Figure 2, comprising:
Input stage circuit 201, this input stage circuit 201 comprises mirror image circuit 204, Differential input circuit A210, Differential input circuit B211, to provide the biasing circuit A212 of bias current for Differential input circuit A210 and provide the biasing circuit B213 of bias current for Differential input circuit B211;
Output-stage circuit 202, this output-stage circuit 202 is provided input voltage by the output B of mirror image circuit and is formed output voltage;
Differential mode feedback circuit 203, the difference of this differential mode feedback circuit 203 pairs of input voltages and output voltage detects, and final feedback signal eliminates offset voltage by the biasing circuit 212,213 controlling two input stage circuits respectively.
Wherein, this Differential input circuit A210 and Differential input circuit B211 are that the identical input of parallel connection is to pipe.This input is different to the size of the metal-oxide-semiconductor of two in pipe.The connection of Differential input circuit A210, Differential input circuit B211 and mirror image circuit 204 adopts cross interconnected method.The mutual conductance of two input pipes in described Differential input circuit A210 is asymmetric, and the mutual conductance of the metal-oxide-semiconductor be wherein connected with output terminals A 214 in mirror image circuit 204 is larger than the mutual conductance of the metal-oxide-semiconductor be connected with output B215 in mirror image circuit 204; Equally, the mutual conductance of two input pipes in Differential input circuit B211 is also asymmetric, and the mutual conductance of the metal-oxide-semiconductor be wherein connected with output B215 in mirror image circuit 204 is larger than the mutual conductance of the metal-oxide-semiconductor be connected with output terminals A 214 in mirror image circuit 204; Namely Differential input circuit A210 and Differential input circuit B211 has dissymmetrical structure.
Fig. 3 is the circuit diagram of input stage circuit 201 in operational amplifier of the present invention, wherein, metal-oxide-semiconductor M1 connects power vd D and node 314, metal-oxide-semiconductor M2 connects power vd D and node 313, metal-oxide-semiconductor M3 link node 316 and node 313, metal-oxide-semiconductor M4 link node 316 and node 314, metal-oxide-semiconductor M5 link node 314 and node 315, metal-oxide-semiconductor M6 link node 315 and node 313, metal-oxide-semiconductor M7 link node 316 and ground level VSS, metal-oxide-semiconductor M8 link node 315 and ground level VSS.
Metal-oxide-semiconductor M7 and metal-oxide-semiconductor M8 forms a mirror image circuit 204, and metal-oxide-semiconductor M1, metal-oxide-semiconductor M4 and metal-oxide-semiconductor M5 form Differential input circuit A210, and metal-oxide-semiconductor M2, metal-oxide-semiconductor M3 and metal-oxide-semiconductor M6 composition difference enters output circuit B211.Wherein the bias current of M3 with M5 is identical, the bias current of M4 with M6 is identical, the bias current flowing through metal-oxide-semiconductor M3 and M5 is less than the bias current flowing through metal-oxide-semiconductor M4 and M6, the simultaneously wide length of breadth length ratio metal-oxide-semiconductor M4 and M6 of metal-oxide-semiconductor M3 and M5, i.e. little than metal-oxide-semiconductor M4 and M6 of the mutual conductance of metal-oxide-semiconductor M3 and M5.
Fig. 4 is the circuit diagram of differential mode feedback circuit 203 and output-stage circuit 202 in operational amplifier of the present invention.Composition graphs 3 and Fig. 4, the grid of metal-oxide-semiconductor M1 is connected with a difference output 311 of differential mode feedback circuit 203.The grid of metal-oxide-semiconductor M2 is connected with another difference output 312 of differential mode feedback circuit 203.The grid of metal-oxide-semiconductor M3 with M4 is connected with the output voltage Vout of operational amplifier.The grid of metal-oxide-semiconductor M5 with M6 is connected with the input voltage vin of operational amplifier.Metal-oxide-semiconductor M7 is connected with node 316 with the grid of metal-oxide-semiconductor M8.
The grid voltage of metal-oxide-semiconductor M1 and M2 is controlled by the output signal of differential mode feedback circuit 203.Node 315 is the mirror output that metal-oxide-semiconductor M7 and M8 forms mirror image circuit 204.Two pairs of Differential Input pipes are cross interconnected with mirror image circuit 204 respectively.
When output voltage Vout is slightly larger than input voltage vin, in differential mode feedback circuit 203, the gate source voltage of FB2 becomes large, and the electric current I FB2 namely flowing through metal-oxide-semiconductor FB2 becomes large, the voltage of node 312 reduces, according to differential pair operation principle, the electric current flowing through FB3 diminishes, and the voltage of node 311 raises.The voltage of node 311 is the grid voltage of M1, and the rising of this point voltage causes flowing through M1 electric current I M1 and diminishes; Mutual conductance due to M4 is greater than the mutual conductance of M5, therefore the decrease flowing through the electric current of M4 is greater than the decrease of the electric current flowing through M5.In like manner, the voltage of node 312 is the grid voltage of M2, and the reduction of this point voltage causes the electric current I M2 flowing through M2 to become large; Mutual conductance due to M3 is less than the mutual conductance of M6, therefore, flow through the recruitment of electric current in M6 and be greater than the recruitment flowing through electric current in M3.Known by above-mentioned analysis, the electric current flowing through M7 diminishes, and namely the voltage of node 316 reduces; The ER effect flowing through M8 is large, and namely the voltage of node 315 raises.Node 315 voltage acts on the M9 of output-stage circuit 202, and the voltage of output node 319 is reduced.Thus reduce offset error voltage.
When output voltage Vout is slightly less than input voltage vin, in differential mode feedback circuit 203, the gate source voltage of FB2 diminishes, and the electric current I FB2 namely flowing through metal-oxide-semiconductor FB2 diminishes, the voltage of node 312 raises, according to differential pair operation principle, the ER effect flowing through FB3 is large, and the voltage of node 311 reduces.The voltage of node 311 is the grid voltage of M1, and the rising of this point voltage causes flowing through M1 electric current I M1 and becomes large; Mutual conductance due to M4 is greater than the mutual conductance of M5, therefore the recruitment flowing through the electric current of M4 is greater than the recruitment of the electric current of M5 pipe.In like manner, the voltage of node 312 is the grid voltage of M2 pipe, and the rising of this point voltage causes the electric current I M2 flowing through M2 to become large; Mutual conductance due to M3 is less than the mutual conductance of M6, therefore, flow through the decrease of electric current in M6 and be greater than the decrease flowing through electric current in M3.Known by above-mentioned analysis, the ER effect flowing through M7 is large, and namely the voltage of node 316 raises; The electric current flowing through M8 diminishes, and namely the voltage of node 315 reduces.Node 315 voltage acts on the M9 of output-stage circuit 202, and output node 319 voltage is raised, thus reduces offset error voltage.
Claims (6)
1. an operational amplifier, comprise input stage circuit, output-stage circuit, described input stage circuit comprises mirror image circuit, Differential input circuit A, Differential input circuit B, the biasing circuit A of bias current be provided for Differential input circuit A and provide the biasing circuit B of bias current for Differential input circuit B; Described output-stage circuit is provided input voltage by the output B of mirror image circuit and is formed output voltage; It is characterized in that, described operational amplifier also comprises differential mode feedback circuit, described differential mode feedback circuit is connected with output-stage circuit, biasing circuit A and biasing circuit B, for detecting the difference of input voltage and output voltage, two biasing circuits in final feedback signal difference control inputs level circuit.
2. operational amplifier as claimed in claim 1, it is characterized in that, described Differential input circuit A and Differential input circuit B is dissymmetrical structure.
3. operational amplifier as claimed in claim 2, it is characterized in that, the mutual conductance of two input pipes in described Differential input circuit A is asymmetric, and the mutual conductance of the metal-oxide-semiconductor be wherein connected with mirror image circuit output terminals A is greater than the mutual conductance of the metal-oxide-semiconductor be connected with mirror image circuit output B; The mutual conductance of two input pipes in described Differential input circuit B is also asymmetric, and the mutual conductance of the metal-oxide-semiconductor be wherein connected with mirror image circuit output B is greater than the mutual conductance of the metal-oxide-semiconductor be connected with mirror image circuit output terminals A.
4. the operational amplifier as described in claims 1 to 3 any one, is characterized in that, described Differential input circuit A and Differential input circuit B are that the identical input of parallel connection is to pipe.
5. operational amplifier as claimed in claim 4, is characterized in that, described input is different to the metal-oxide-semiconductor size of two in pipe.
6. operational amplifier as claimed in claim 4, it is characterized in that, the input of described Differential input circuit A and Differential input circuit B is cross interconnected with mirror image circuit respectively to pipe.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410626421.5A CN104378073A (en) | 2014-11-07 | 2014-11-07 | Operational amplifier |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410626421.5A CN104378073A (en) | 2014-11-07 | 2014-11-07 | Operational amplifier |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN104378073A true CN104378073A (en) | 2015-02-25 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410626421.5A Pending CN104378073A (en) | 2014-11-07 | 2014-11-07 | Operational amplifier |
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| CN (1) | CN104378073A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106817092A (en) * | 2015-11-30 | 2017-06-09 | 硅实验室公司 | For the device and correlation technique of offset correction in electronic circuit |
| CN112567464A (en) * | 2018-08-16 | 2021-03-26 | 美国亚德诺半导体公司 | Correlated double sampling amplifier for low power |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20050174174A1 (en) * | 2004-02-10 | 2005-08-11 | Samsung Electronics Co., Ltd. | OP-amplifier with an offset voltage cancellation circuit |
| CN2724295Y (en) * | 2004-08-16 | 2005-09-07 | 周宗善 | High speed high gain amplifier |
| CN101599742A (en) * | 2008-06-02 | 2009-12-09 | 恩益禧电子股份有限公司 | Amplifier and offset regulating circuit |
| CN102571004A (en) * | 2010-12-27 | 2012-07-11 | 无锡华润上华半导体有限公司 | Operational amplifier |
| CN104113295A (en) * | 2014-04-30 | 2014-10-22 | 西安电子科技大学昆山创新研究院 | Low-voltage fully-differential operation amplifier circuit |
-
2014
- 2014-11-07 CN CN201410626421.5A patent/CN104378073A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20050174174A1 (en) * | 2004-02-10 | 2005-08-11 | Samsung Electronics Co., Ltd. | OP-amplifier with an offset voltage cancellation circuit |
| CN2724295Y (en) * | 2004-08-16 | 2005-09-07 | 周宗善 | High speed high gain amplifier |
| CN101599742A (en) * | 2008-06-02 | 2009-12-09 | 恩益禧电子股份有限公司 | Amplifier and offset regulating circuit |
| CN102571004A (en) * | 2010-12-27 | 2012-07-11 | 无锡华润上华半导体有限公司 | Operational amplifier |
| CN104113295A (en) * | 2014-04-30 | 2014-10-22 | 西安电子科技大学昆山创新研究院 | Low-voltage fully-differential operation amplifier circuit |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106817092A (en) * | 2015-11-30 | 2017-06-09 | 硅实验室公司 | For the device and correlation technique of offset correction in electronic circuit |
| CN106817092B (en) * | 2015-11-30 | 2022-04-29 | 硅实验室公司 | Apparatus, and associated method, for offset correction in electronic circuits |
| CN112567464A (en) * | 2018-08-16 | 2021-03-26 | 美国亚德诺半导体公司 | Correlated double sampling amplifier for low power |
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Application publication date: 20150225 |