CN102571004A - Operational amplifier - Google Patents
Operational amplifier Download PDFInfo
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- CN102571004A CN102571004A CN2010106053540A CN201010605354A CN102571004A CN 102571004 A CN102571004 A CN 102571004A CN 2010106053540 A CN2010106053540 A CN 2010106053540A CN 201010605354 A CN201010605354 A CN 201010605354A CN 102571004 A CN102571004 A CN 102571004A
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Abstract
The invention provides an operational amplifier. The operational amplifier comprises an input-stage circuit, an output-stage circuit and a difference-mode feedback circuit, wherein the input-stage circuit comprises a mirror circuit, a differential input circuit A, a differential input circuit B, a bias circuit A and a bias circuit B; the bias circuit A is used for providing a bias current to the differential input circuit A; the bias circuit B is used for providing a bias current to the differential input circuit B; the output end B of the mirror circuit provides an input voltage to the output-stage circuit and forms an output voltage; the difference-mode feedback circuit is used for detecting the difference between the input voltage and the output voltage; and the offset voltage of the final feedback signal is eliminated by controlling the bias circuits of the two input-stage circuits respectively. The operational amplifier has the following beneficial effect: elimination of the offset voltage of the operational amplifier is realized by additionally arranging one difference-mode feedback circuit on the premise of not adding the circuit complexity, thus solving the problem of quiescent point drift of the operational amplifier caused by operating temperature variation.
Description
[technical field]
The present invention relates to a kind of operational amplifier, relate in particular to a kind of operational amplifier that is used to drive such as the capable load of electric capacity of liquid crystal indicator.
[background technology]
Traditionally, in most of the cases used bipolar transistor construction operation amplifier.But, because for the coexistence of MOS circuit and bipolar transistor and for the continuous requirement of low power run, and to compare in the past, use MOS transistor construction operation amplifier is more common.When with MOS transistor construction operation amplifier, there is following situation, promptly be different from circuit structure with the operational amplifier of bipolar transistor structure through utilizing the intrinsic mode characteristic of MOS transistor to adopt.The example of this kind operational amplifier comprises the amplifier that uses the electronics handoff functionality.
With one of application of MOS transistor construction operation amplifier is TFT LCD (tft liquid crystal demonstration) driver LSI.This lcd driver LSI comprises that a plurality of operational amplifiers with voltage follower configuration are as output buffer amplifier and the GTG power supply that is used for gamma correction.Require lcd driver LSI that little difference is only being arranged aspect the offset voltage of said a plurality of operational amplifier kinds.Therefore, require to have the MOS operational amplifier of extremely little offset voltage in the art.
In the unit gain operational amplifier of traditional closed-loop structure, two-stage unit gain discharge circuit is mainly through increasing dual-sampling circuit, improve the symmetry of input stage metal-oxide-semiconductor and using wave chopping technology to eliminate the offset voltage of amplifier on output.With reference to shown in Figure 1, this discharge circuit comprises biasing circuit, input stage circuit and output-stage circuit three parts.Input stage has been used the difference input structure of being made up of metal-oxide-semiconductor M1, M2, M5.Output-stage circuit is made up of M6, M7 and capacitor C c and CL, amplifies the signal of difference output as the second level of amplifier, and capacitor C c is a miller capacitance, regulates the stability of amplifier.This circuit also comprises an image current mirror that is made up of M3 and M4.But, increase dual-sampling circuit and use wave chopping technology all to increase the complexity of circuit; Because technology, input also can't be eliminated the mismatch problems of pipe fully; Wave chopping technology needs the extra circuit and the clock signal of certain frequency to realize.
In view of above drawback, but be necessary to provide a kind of novel operational amplifier to solve above-mentioned defective.
[summary of the invention]
The object of the present invention is to provide a kind of in order to solve in the prior art owing to technology manufacturing reason causes the influence of the mismatch of metal-oxide-semiconductor to offset voltage.
The technical scheme that realizes above-mentioned purpose is: a kind of operational amplifier, and it comprises:
Input stage circuit, the biasing circuit B that it comprises mirror image circuit, difference input circuit A, difference input circuit B, the biasing circuit A of bias current is provided and bias current is provided for difference input circuit B for difference input circuit A;
Output-stage circuit, its output B by mirror image circuit provides input voltage and forms output voltage; And
The differential mode feedback circuit, its difference to input voltage and output voltage detects, and final feedback signal is eliminated offset voltage through the biasing circuit of controlling two input stage circuits respectively.
Alternatively, said difference input circuit A and difference input circuit B are set to improve the dissymmetrical structure of feedback voltage gain respectively.
Alternatively, the mutual conductance of two input pipes among the said difference input circuit A is asymmetric, wherein with mirror image circuit in the metal-oxide-semiconductor that links to each other of output terminals A mutual conductance than with mirror image circuit in the mutual conductance of the metal-oxide-semiconductor that links to each other of output B big.
Alternatively, the mutual conductance of two input pipes among the said difference input circuit B also is asymmetric, wherein with mirror image circuit in the metal-oxide-semiconductor that links to each other of output B mutual conductance than with mirror image circuit in the mutual conductance of the metal-oxide-semiconductor that links to each other of output terminals A big.
Alternatively, said difference input circuit A and difference input circuit B are that the identical input of parallel connection is to pipe.
Alternatively, said input is different to the size of two metal-oxide-semiconductors in the pipe.
Alternatively, the input of said difference input circuit A and difference input circuit B is to pipe cross interconnected with mirror image circuit.
Compared with prior art; The beneficial effect of above-mentioned operational amplifier is: operational amplifier of the present invention is under the prerequisite that does not increase circuit complexity; Realize the elimination of offset voltage through increasing a differential mode feedback circuit, solved operational amplifier because the quiescent point drifting problem that temperature change produces.
Operational amplifier of the present invention has used the input pipe of dissymmetrical structure in input stage circuit, avoided the mismatch error that input pipe forms of traditional symmetrical structure when improving the feedback control loop voltage gain.
[description of drawings]
Fig. 1 is a kind of two-stage unit gain discharge circuit structural representation of prior art;
Fig. 2 is the theory diagram of the execution mode of operational amplifier of the present invention;
Fig. 3 is the circuit diagram of input stage circuit in the operational amplifier of the present invention;
Fig. 4 is the circuit diagram of differential mode feedback circuit and output-stage circuit in the operational amplifier of the present invention.
[embodiment]
With reference to shown in Figure 2; Operational amplifier of the present invention is under the prerequisite that does not increase the complicated circuit degree; Realize the elimination of offset voltage through increasing the differential mode feedback circuit, input pipe is set to dissymmetrical structure in input stage circuit simultaneously, the mismatch error of having avoided traditional amplifier to exist.
Below specifically introduce this execution mode amplifier architecture:
Operational amplifier of the present invention comprises:
Input stage circuit 201, the biasing circuit B213 that it comprises mirror image circuit 204, difference input circuit A210, difference input circuit B211, the biasing circuit A212 of bias current is provided and bias current is provided for difference input circuit B211 for difference input circuit A210;
Output-stage circuit 202, its output B by mirror image circuit provides input voltage and forms output voltage;
And differential mode feedback circuit 203, its difference to input voltage and output voltage detects, and final feedback signal realizes eliminating the purpose of offset voltage through the biasing circuit 212,213 of controlling two input stage circuits respectively.
Wherein, this difference input circuit A210 and difference input circuit B211 are that the identical input of parallel connection is to pipe.This input is different to the size of two metal-oxide-semiconductors in the pipe.Difference input circuit A210, difference input circuit B211 adopt cross interconnected method with being connected of mirror image circuit 204.The mutual conductance of two input pipes among the said difference input circuit A210 is asymmetric; Wherein with mirror image circuit 204 in the metal-oxide-semiconductor that links to each other of output terminals A 214 mutual conductance than with mirror image circuit 204 in the mutual conductance of the metal-oxide-semiconductor that links to each other of output B215 big; Equally; The mutual conductance of two input pipes among the difference input circuit B211 also is asymmetric, wherein with mirror image circuit 204 in the metal-oxide-semiconductor that links to each other of output B215 mutual conductance than with mirror image circuit 204 in the mutual conductance of the metal-oxide-semiconductor that links to each other of output terminals A 214 big.That is, difference input circuit A210 and difference input circuit B211 have dissymmetrical structure.
With reference to shown in Figure 3, it is the circuit diagram of input stage circuit 201 in the operational amplifier of the present invention, wherein; Metal-oxide-semiconductor M1 connects power vd D and node 314, and 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 form a mirror image circuit 204, and metal-oxide-semiconductor M1, metal-oxide-semiconductor M4 and metal-oxide-semiconductor M5 form differential output circuit A210, and metal-oxide-semiconductor M2, metal-oxide-semiconductor M3 and metal-oxide-semiconductor M6 form differential output circuit B211.Wherein the bias current of M3 and M5 is identical; The bias current of M4 and M6 is identical; The bias current of metal-oxide-semiconductor M3 and M5 of flowing through is littler than the bias current of flow through metal-oxide-semiconductor M4 and M6; While metal-oxide-semiconductor M3 and the breadth length ratio metal-oxide-semiconductor M4 of M5 and the wide length of M6, i.e. the mutual conductance of metal-oxide-semiconductor M3 and M5 is littler than metal-oxide-semiconductor M4 and M6's.
With reference to shown in Figure 4, it is the circuit diagram of differential mode feedback circuit 203 and output-stage circuit 202 in the operational amplifier of the present invention.
Combine shown in Figure 4ly with reference to Fig. 3, a difference output 311 of the grid of metal-oxide-semiconductor M1 and differential mode feedback circuit 203 links to each other.The grid of metal-oxide-semiconductor M2 links to each other with another difference output 312 of differential mode feedback circuit 203.The grid of metal-oxide-semiconductor M3 and M4 links to each other with the output voltage V out of operational amplifier.The grid of metal-oxide-semiconductor M5 and M6 links to each other with the input voltage vin of operational amplifier.The grid of metal-oxide-semiconductor M7 and metal-oxide-semiconductor M8 links to each other with node 316.
The grid voltage of metal-oxide-semiconductor M1 and M2 is by the output signal controlling of differential mode feedback circuit 203.Node 315 is the mirror image output that metal-oxide-semiconductor M7 and M8 form mirror image circuit 204.Two pairs of difference input pipes are cross interconnected with mirror image circuit 204 respectively.
With reference to shown in Figure 4; When output voltage V out was slightly larger than input voltage vin, the gate source voltage of FB2 became big in the differential mode feedback circuit 203, and it is big that the electric current I FB2 of the metal-oxide-semiconductor FB2 that promptly flows through becomes; The voltage of node 312 reduces; According to the differential pair operation principle, the electric current of the FB3 that flows through 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 M1 electric current I M1 that causes flowing through diminishes; Because the mutual conductance of M4 is greater than the mutual conductance of M5, so the decrease of the electric current of the M4 that flows through is greater than the decrease of the electric current of the M5 that flows through.In like manner, the voltage of node 312 is the grid voltage of M2, and the reduction of this point voltage cause the flowing through electric current I M2 of M2 becomes big; Because the mutual conductance of M3 is less than the mutual conductance of M6, so the recruitment of electric current is greater than the recruitment of electric current among the M3 that flows through among the M6 that flows through.Can know that through above-mentioned analysis the electric current of the M7 that flows through diminishes, promptly the voltage of node 316 reduces; The electrorheological of M8 of flowing through is big, and promptly the voltage of node 315 raises.Node 315 voltages act on the M9 of output-stage circuit 202, make the voltage of output node 319 reduce.Thereby reduce offset error voltage.
With reference to shown in Figure 4; When output voltage V out was slightly less than input voltage vin, the gate source voltage of FB2 diminished in the differential mode feedback circuit 203, and the electric current I FB2 of the metal-oxide-semiconductor FB2 that promptly flows through diminishes; The voltage of node 312 raises; According to the differential pair operation principle, the electrorheological of the FB3 that flows through is big, 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 change greatly; Because the mutual conductance of M4 is greater than the mutual conductance of M5, so the recruitment of the electric current of the M4 that flows through 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 cause the flowing through electric current I M2 of M2 becomes big; Because the mutual conductance of M3 is less than the mutual conductance of M6, so the decrease of electric current is greater than the decrease of electric current among the M3 that flows through among the M6 that flows through.Can know that through above-mentioned analysis the electrorheological of the M7 that flows through is big, promptly the voltage of node 316 raises; The electric current of M8 of flowing through diminishes, and promptly the voltage of node 315 reduces.Node 315 voltages act on the M9 of output-stage circuit 202, make output node 319 voltages raise.Thereby reduce offset error voltage.
In sum, operational amplifier of the present invention is realized the elimination of offset voltage through increasing a differential mode feedback circuit under the prerequisite that does not increase circuit complexity; In input stage circuit, use the input pipe of dissymmetrical structure, thereby avoided the input pipe of traditional symmetrical structure to form mismatch error.
Though the present invention discloses as above with preferred embodiment, the present invention is defined in this.Any those skilled in the art are not breaking away from the spirit and scope of the present invention, all can do various changes and modification, so protection scope of the present invention should be as the criterion with claim institute restricted portion.
Claims (7)
1. operational amplifier is characterized in that it comprises:
Input stage circuit, the biasing circuit B that it comprises mirror image circuit, difference input circuit A, difference input circuit B, the biasing circuit A of bias current is provided and bias current is provided for difference input circuit B for difference input circuit A;
Output-stage circuit, its output B by mirror image circuit provides input voltage and forms output voltage; And
The differential mode feedback circuit, its difference to input voltage and output voltage detects, and final feedback signal is eliminated offset voltage through the biasing circuit of controlling two input stage circuits respectively.
2. operational amplifier as claimed in claim 1 is characterized in that, said difference input circuit A and difference input circuit B are set to improve the dissymmetrical structure of feedback voltage gain respectively.
3. operational amplifier as claimed in claim 2; It is characterized in that; The mutual conductance of two input pipes among the said difference input circuit A is asymmetric, wherein with mirror image circuit in the metal-oxide-semiconductor that links to each other of output terminals A mutual conductance than with mirror image circuit in the mutual conductance of the metal-oxide-semiconductor that links to each other of output B big.
4. operational amplifier as claimed in claim 3; It is characterized in that; The mutual conductance of two input pipes among the said difference input circuit B also is asymmetric, wherein with mirror image circuit in the metal-oxide-semiconductor that links to each other of output B mutual conductance than with mirror image circuit in the mutual conductance of the metal-oxide-semiconductor that links to each other of output terminals A big.
5. like any described operational amplifier of claim 1 to 4, it is characterized in that said difference input circuit A and difference input circuit B are that the identical input of parallel connection is to pipe.
6. operational amplifier as claimed in claim 5 is characterized in that, said input is different to the size of two metal-oxide-semiconductors in the pipe.
7. operational amplifier as claimed in claim 6 is characterized in that, the input of said difference input circuit A and difference input circuit B is cross interconnected to pipe and mirror image circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010106053540A CN102571004A (en) | 2010-12-27 | 2010-12-27 | Operational amplifier |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010106053540A CN102571004A (en) | 2010-12-27 | 2010-12-27 | Operational amplifier |
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| Publication Number | Publication Date |
|---|---|
| CN102571004A true CN102571004A (en) | 2012-07-11 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN2010106053540A Pending CN102571004A (en) | 2010-12-27 | 2010-12-27 | Operational amplifier |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103780212A (en) * | 2012-10-25 | 2014-05-07 | 华为技术有限公司 | Operational amplifiers, level switching circuit and programmable gain amplifier |
| CN104378073A (en) * | 2014-11-07 | 2015-02-25 | 无锡纳讯微电子有限公司 | Operational amplifier |
| CN106953605A (en) * | 2017-03-22 | 2017-07-14 | 中国电子科技集团公司第二十四研究所 | The high performance operational amplifier of JFET inputs |
| CN108073218A (en) * | 2016-11-08 | 2018-05-25 | 中芯国际集成电路制造(上海)有限公司 | Operation amplifier circuit and band gap reference |
Citations (3)
| 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 |
| CN101471048A (en) * | 2007-12-27 | 2009-07-01 | 比亚迪股份有限公司 | TFT-LCD driving circuit and LCD device |
-
2010
- 2010-12-27 CN CN2010106053540A patent/CN102571004A/en active Pending
Patent Citations (3)
| 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 |
| CN101471048A (en) * | 2007-12-27 | 2009-07-01 | 比亚迪股份有限公司 | TFT-LCD driving circuit and LCD device |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103780212A (en) * | 2012-10-25 | 2014-05-07 | 华为技术有限公司 | Operational amplifiers, level switching circuit and programmable gain amplifier |
| CN103780212B (en) * | 2012-10-25 | 2016-12-21 | 华为技术有限公司 | A kind of operational amplifier, level shifting circuit and programmable gain amplifier |
| CN104378073A (en) * | 2014-11-07 | 2015-02-25 | 无锡纳讯微电子有限公司 | Operational amplifier |
| CN108073218A (en) * | 2016-11-08 | 2018-05-25 | 中芯国际集成电路制造(上海)有限公司 | Operation amplifier circuit and band gap reference |
| CN106953605A (en) * | 2017-03-22 | 2017-07-14 | 中国电子科技集团公司第二十四研究所 | The high performance operational amplifier of JFET inputs |
| CN106953605B (en) * | 2017-03-22 | 2020-01-31 | 中国电子科技集团公司第二十四研究所 | High-performance operational amplifier with JFET input |
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Free format text: FORMER OWNER: WUXI HUARUN SHANGHUA TECHNOLOGY CO., LTD. Effective date: 20131216 |
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| TA01 | Transfer of patent application right |
Effective date of registration: 20131216 Address after: 214028 Wuxi provincial high tech Industrial Development Zone, Hanjiang Road, No. 5, Jiangsu, China Applicant after: Wuxi CSMC Semiconductor Co., Ltd. Address before: 214028 Wuxi provincial high tech Industrial Development Zone, Hanjiang Road, No. 5, Jiangsu, China Applicant before: Wuxi CSMC Semiconductor Co., Ltd. Applicant before: Wuxi Huarun Shanghua Technology Co., Ltd. |
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| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20120711 |
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| WD01 | Invention patent application deemed withdrawn after publication |