CN105743446A - Drift voltage correcting circuit for instrument amplifier - Google Patents
Drift voltage correcting circuit for instrument amplifier Download PDFInfo
- Publication number
- CN105743446A CN105743446A CN201610058106.6A CN201610058106A CN105743446A CN 105743446 A CN105743446 A CN 105743446A CN 201610058106 A CN201610058106 A CN 201610058106A CN 105743446 A CN105743446 A CN 105743446A
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- amplifier
- correcting circuit
- voltage
- instrument amplifier
- drift voltage
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- 150000004706 metal oxides Chemical class 0.000 abstract 2
- 239000004065 semiconductor Substances 0.000 abstract 2
- 238000004164 analytical calibration Methods 0.000 description 4
- 230000003321 amplification Effects 0.000 description 3
- 238000003199 nucleic acid amplification method Methods 0.000 description 3
- 101000649929 Homo sapiens Serine/threonine-protein kinase VRK1 Proteins 0.000 description 2
- 102100028235 Serine/threonine-protein kinase VRK1 Human genes 0.000 description 2
- 238000000034 method Methods 0.000 description 2
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- 238000004364 calculation method Methods 0.000 description 1
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- 229920006395 saturated elastomer Polymers 0.000 description 1
- 230000026676 system process Effects 0.000 description 1
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
- H03F1/303—Modifications of amplifiers to reduce influence of variations of temperature or supply voltage or other physical parameters using a switching device
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Amplifiers (AREA)
- Measuring Fluid Pressure (AREA)
Abstract
The invention discloses a drift voltage correcting circuit for an instrument amplifier. The circuit comprises an input voltage, an operational amplifier OP1 and a correcting circuit, wherein the input voltage is connected with a positive end of the operational amplifier OP1; an output end of the operational amplifier is connected with the correcting circuit; and the correcting circuit consists of three NMOS (N-channel Metal Oxide Semiconductor) transistors, namely, MN1/MN2/MN3 and three PMOS (P-channel Metal Oxide Semiconductor) transistors which are connected in series, namely, MP1/MP2/MP3. Through adoption of the drift voltage correcting circuit, a drift voltage of the instrument amplifier or a drift voltage in a sensor signal can be corrected; an input range of the instrument amplifier is expanded; more types of sensor signals can be processed; and the input range of the instrument amplifier and the types of the sensor signals which can be processed by the instrument amplifier are extended.
Description
Technical field
The invention belongs to technical field of integrated circuits, particularly to the correcting circuit of the drift voltage being applied to instrument amplifier circuit.
Background technology
The Main Function of instrument amplifier is in that amplified difference signal, it is suppressed that common-mode signal, improves signal to noise ratio, is the common circuit module of high-precision signal acquisition system.The signal that signal acquiring system processes includes the output small-signal of the sensor such as pressure transducer, temperature sensor, and bioelectrical signals etc..These signals, after instrument amplifier amplifies, are converted to digital signal by high-precision adc, then by CPU or MCU process.So, the precision of instrument amplifier is directly connected to the precision of whole signals collecting signal.
The typical structure of instrument amplifier is as it is shown in figure 1, be made up of the feedback circuit of two amplifiers.Input signal anode VINP is as the positive input of amplifier OP1, and negative input signal end VINN is as the negative input of amplifier OP2, and the output VOUTP/VOUTN of amplifier OP1/OP2 is supplied to ADC as differential signal.Node VCM is the common mode operating point of instrument amplifier differential output signal, this point voltage common mode operating point equal to input signal VINP and VINN.
Instrument amplifier is by amplifying input signal, it is suppressed that the mode of noise improves signal to noise ratio.If the input signal packet composition containing drift voltage, then this drift voltage also can be amplified by instrument amplifier.Such as, the drift voltage of certain pressure transducer is 10mV, namely also can export the differential signal of 10mV at the situation lower sensor not having pressing, and after the instrument amplifier that amplification is 16 times, this drift voltage becomes 160mV, and situation worsens further.
Use instrument amplifier, another drawback of sensor signal is in that input range also reduces therewith, and the signal exceeding this range will make instrument amplifier and ADC overflow, and cannot obtain effective data.If input signal packet is containing drift voltage, this problem can be more serious.Such as, the instrument amplifier that amplification is 16 provides differential signal to use to a high-precision adc, and the differential signal input range of this ADC is 0～1500mV.Instrument amplifier amplifies the pressure sensor signal that a drift voltage is 10mV, then drift voltage becomes 160mV after instrument amplifier, then the actual treatable differential signal input range of ADC is reduced to 0～1340mV.In worse situation, if the drift voltage of pressure transducer is equal to 100mV, instrument amplifier will be amplified to 1600mV, and even more than the input range of ADC, the signal of pressure transducer can not be processed by this signal acquiring system completely.
Such as patent application 90107838.7 discloses a kind of offset-voltage-balancing operational amplifier, the differential wave (ds) of this invention balancing operational amplifier that drifts about is made up of an auxiliary amplifier (av) and a main amplifier (mv), each amplifier has a differential input (i-[1], i-[2]) and auto zero input (Z-[1], Z-[2]).In order to provide drift equilibrium, auto zero input and two integrated storage electric capacity (C-[1], C-[2]) on voltage connect, the differential input of auxiliary amplifier can be switched (S-[1] by first and second, S-[2]) short circuit, first and second storage electric capacity (C-[1], C-[2]) it is connected with the output of auxiliary amplifier by the third and fourth switch, auto zero input (Z-[1], Z-[2]) the sensitivity sensitivity less than differential input (i-[1], i-[2]).But, this patent application may only the drift voltage of correction calculation amplifier, but can not the drift voltage of instrument calibration amplifier and sensor.
Summary of the invention
For this, it is to provide a kind of drift voltage correcting circuit for instrument amplifier the primary order of the present invention, this circuit can drift voltage in the drift voltage of instrument calibration amplifier or sensor signal, extend the input range of instrument amplifier, it is possible to the more sensor signal for the treatment of types.
Another order ground of the present invention is in that to provide a kind of drift voltage correcting circuit for instrument amplifier, and this circuit realiration is easy, with low cost.
For achieving the above object, the technical scheme is that
A kind of drift voltage correcting circuit for instrument amplifier, this circuit includes:
One input voltage, described input voltage is to be produced by two resistance RK1/RK2 divider node VRK0 being series at together, and further, said two is series at resistance RK1/RK2 mono-together and terminates VS, one end ground connection.
One operational amplifier OP1, described input voltage connects the anode of operational amplifier OP1；The outfan of operational amplifier OP1 is connected to correcting circuit；
Described correcting circuit, is made up of tri-NMOS tube of MN1/MN2/MN3 and tri-PMOS of MP1/MP2/MP3 being serially connected together；After tri-PMOS of described MP1/MP2/MP3 are serially connected with MN1, MN1 is connected on the outfan of OP1, and tri-PMOS of described MP1/MP2/MP3 are connected to VS respectively.
Further, described MN2/MN3 is cascaded, and is connected on MP2 by MN2；Described output current lcp I is exported by MP3, and described input circuit ICN is input to MN3.
The drift voltage correcting circuit that the present invention realizes can drift voltage in the drift voltage of instrument calibration amplifier or sensor signal, extend the input range of instrument amplifier, can the more sensor signal for the treatment of types, expanded the input range of instrument amplifier and treatable kind of sensor.
Accompanying drawing explanation
Fig. 1 is the circuit diagram that prior art is implemented.
Fig. 2 is the instrument amplifier of institute of the present invention out tape drift voltage correcting circuit.
Fig. 3 is the instrument amplifier drift voltage correcting circuit that the present invention implements.
Detailed description of the invention
In order to make the purpose of the present invention, technical scheme and advantage clearly understand, below in conjunction with drawings and Examples, the present invention is further elaborated.Should be appreciated that specific embodiment described herein is only in order to explain the present invention, is not intended to limit the present invention.
Referring to shown in accompanying drawing 2, Fig. 2 being the instrument amplifier with drift voltage correcting circuit, wherein: OP1/OP2 is amplifier；R1A/R2A/R1B/R2B is resistance；VINP/VINN is input signal；VOUTP/VOUTN is output signal；VCM is node voltage；VS is supply voltage.
Its principle is to offset drift voltage in pressure drop produced by resistance R1 and R2 pullup or pulldown electric current.The basis of available circuit adds sensor and instrument amplifier drift voltage correcting circuit.Wherein, the output signal of sensor is exactly input signal VINP and the VINN of two operational amplifiers；One road operational amplifier OP2 is to instrument amplifier drift voltage correcting circuit input current ICN, and instrument amplifier drift voltage correcting circuit exports current lcp I to another road operational amplifier OP1.
It should be understood that
Owing to the voltage of node VCM is determined by the common mode operating point inputting signal VINP and VINN, if using voltage source directly to change R1A and R1B both end voltage, in the uncertain situation of drift voltage size, it is easy to the output making instrument amplifier is saturated.
The method of current source is a lot, but owing to instrument amplifier requires that output signal has higher signal to noise ratio, so this current source also must have the characteristic of low noise.
The current source of the present invention designs particular for the drift voltage Correction Problems of instrument amplifier, the noise of circuit itself is relatively low, and owing to the power supply of sensor and the power supply of instrument amplifier are all VS, so this noise is also relevant to the input noise of sensor, it is possible to offset part input noise.
The amplification of output signal is to be determined by the ratio of resistance R1 and R2, offset or the drift voltage of school positive input signal or instrument amplifier, it is simply that will offset the voltage on resistance R1/R2.
It it is the drift voltage correcting circuit of instrument amplifier proposed by the invention shown in Fig. 3.Wherein, OP1 is amplifier；RK1/RK2/R0 is resistance；MN1/MN2/MN3 is NMOS tube；MP1/MP2/MP3 is PMOS；VRK0/VRK1 is node voltage；ICN/ICP/IP1 is branch current.
The principle of this circuit is, by the resistance RK1/RK2 divider node VRK0 anode input voltage as amplifier OP1, this voltage is fed back to node VRK1 by amplifier, so, branch current IP1=RK2/ (RK1+RK2) * VS/R0, proportional to VS.Wherein, VS voltage, amplifier OP1, resistance RK1/RK2/R0 can introduce noise in electric current IP1, by compressing the bandwidth of amplifier OP1 and selecting less RK1/RK2/R0 resistance their influence of noise to be reduced.And the noise of VS introducing is relevant to input noise, the circuit framework shown in Fig. 2 will not introduce extra noise component(s).
One input voltage, described input voltage is to be produced by sensor, produces particular for voltage sensitive sensor RK1/RK2 divider node VRK0, and further, said two is series at resistance RK1/RK2 mono-together and terminates VS, one end ground connection.
One operational amplifier OP1, described input voltage connects the anode of operational amplifier OP1；The outfan of operational amplifier OP1 is connected to correcting circuit；
Described correcting circuit, is made up of tri-NMOS tube of MN1/MN2/MN3 and tri-PMOS of MP1/MP2/MP3 being serially connected together；After tri-PMOS of described MP1/MP2/MP3 are serially connected with MN1, MN1 is connected on the outfan of OP1, and tri-PMOS of described MP1/MP2/MP3 are connected to VS respectively.
Further, described MN2/MN3 is cascaded, and is connected on MP2 by MN2；Described output current lcp I is exported by MP3, and described input circuit ICN is input to MN3.
Assuming that the drift voltage of sensor or the input drift voltage of instrument amplifier are equal to VOS, in order to offset the impact of drift voltage, required electric current is equal to ICP=ICN=VOS/ (R2A+R2B).
Thus, drift voltage correcting circuit can drift voltage in the drift voltage of instrument calibration amplifier or sensor signal, extend the input range of instrument amplifier, it is possible to the more sensor signal for the treatment of types, expand the input range of instrument amplifier and treatable kind of sensor.
The foregoing is only presently preferred embodiments of the present invention, not in order to limit the present invention, all any amendment, equivalent replacement and improvement etc. made within the spirit and principles in the present invention, should be included within protection scope of the present invention.
Claims (4)
1., for a drift voltage correcting circuit for instrument amplifier, this circuit includes:
One input voltage,
One operational amplifier OP1, described input voltage connects the anode of operational amplifier OP1；The outfan of operational amplifier OP1 is connected to correcting circuit；
One correcting circuit, is made up of tri-NMOS tube of MN1/MN2/MN3 and tri-PMOS of MP1/MP2/MP3 being serially connected together；After tri-PMOS of described MP1/MP2/MP3 are serially connected with MN1, MN1 is connected on the outfan of OP1, and tri-PMOS of described MP1/MP2/MP3 are connected to VS respectively.
2. the drift voltage correcting circuit for instrument amplifier as claimed in claim 1, it is characterised in that described input voltage is to be produced by sensor.
3. the drift voltage correcting circuit for instrument amplifier as claimed in claim 2, it is characterised in that the power supply termination VS of sensor.
4. the drift voltage correcting circuit for instrument amplifier as claimed in claim 1, it is characterised in that described MN2/MN3 is cascaded, and is connected on MP2 by MN2；Described output current lcp I is exported by MP3, and described input circuit ICN is input to MN3.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610058106.6A CN105743446B (en) | 2016-01-28 | 2016-01-28 | A kind of drift voltage correcting circuit for instrument amplifier |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610058106.6A CN105743446B (en) | 2016-01-28 | 2016-01-28 | A kind of drift voltage correcting circuit for instrument amplifier |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN105743446A true CN105743446A (en) | 2016-07-06 |
| CN105743446B CN105743446B (en) | 2018-12-18 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201610058106.6A Ceased CN105743446B (en) | 2016-01-28 | 2016-01-28 | A kind of drift voltage correcting circuit for instrument amplifier |
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| CN (1) | CN105743446B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112764447A (en) * | 2021-04-07 | 2021-05-07 | 上海艾为微电子技术有限公司 | Dynamic offset calibration circuit, method, chip and electronic equipment |
| WO2023116869A1 (en) * | 2021-12-24 | 2023-06-29 | 芯海科技（深圳）股份有限公司 | Drift voltage correction circuit, integrated circuit, measurement apparatus, and electronic device |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101119103A (en) * | 2006-08-02 | 2008-02-06 | 盛群半导体股份有限公司 | Device for correcting input offset voltage |
| CN101806602A (en) * | 2009-12-23 | 2010-08-18 | 哈尔滨工业大学 | Piezoresistive sensor circuit capable of automatically correcting zero-bias |
| JP2010226198A (en) * | 2009-03-19 | 2010-10-07 | Fujitsu Ltd | Power amplifying device and power amplifying method |
| CN102136827A (en) * | 2011-05-10 | 2011-07-27 | 覃超 | Differential amplifier capable of compensating input offset voltage and compensating method |
| CN103036512A (en) * | 2012-12-17 | 2013-04-10 | 清华大学深圳研究生院 | Dynamic comparator with large offset voltage correction range |
-
2016
- 2016-01-28 CN CN201610058106.6A patent/CN105743446B/en not_active Ceased
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101119103A (en) * | 2006-08-02 | 2008-02-06 | 盛群半导体股份有限公司 | Device for correcting input offset voltage |
| JP2010226198A (en) * | 2009-03-19 | 2010-10-07 | Fujitsu Ltd | Power amplifying device and power amplifying method |
| CN101806602A (en) * | 2009-12-23 | 2010-08-18 | 哈尔滨工业大学 | Piezoresistive sensor circuit capable of automatically correcting zero-bias |
| CN102136827A (en) * | 2011-05-10 | 2011-07-27 | 覃超 | Differential amplifier capable of compensating input offset voltage and compensating method |
| CN103036512A (en) * | 2012-12-17 | 2013-04-10 | 清华大学深圳研究生院 | Dynamic comparator with large offset voltage correction range |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112764447A (en) * | 2021-04-07 | 2021-05-07 | 上海艾为微电子技术有限公司 | Dynamic offset calibration circuit, method, chip and electronic equipment |
| WO2023116869A1 (en) * | 2021-12-24 | 2023-06-29 | 芯海科技（深圳）股份有限公司 | Drift voltage correction circuit, integrated circuit, measurement apparatus, and electronic device |
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| Publication number | Publication date |
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| CN105743446B (en) | 2018-12-18 |
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Decision date of declaring invalidation: 20220526 Decision number of declaring invalidation: 56018 Granted publication date: 20181218 |