CN113965172A - Chopping operational amplification circuit suitable for infrared image CMOS sensor - Google Patents

Chopping operational amplification circuit suitable for infrared image CMOS sensor Download PDF

Info

Publication number
CN113965172A
CN113965172A CN202111257325.4A CN202111257325A CN113965172A CN 113965172 A CN113965172 A CN 113965172A CN 202111257325 A CN202111257325 A CN 202111257325A CN 113965172 A CN113965172 A CN 113965172A
Authority
CN
China
Prior art keywords
circuit
chopping
input
resistor
sensor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202111257325.4A
Other languages
Chinese (zh)
Inventor
姜岩峰
永若雪
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Jiangnan University
Original Assignee
Jiangnan University
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Jiangnan University filed Critical Jiangnan University
Priority to CN202111257325.4A priority Critical patent/CN113965172A/en
Publication of CN113965172A publication Critical patent/CN113965172A/en
Pending legal-status Critical Current

Links

Images

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
    • H03F1/26—Modifications of amplifiers to reduce influence of noise generated by amplifying elements
    • 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
    • H03F3/45632—Differential amplifiers with semiconductor devices only characterised by the way of common mode signal rejection in differential amplifiers with FET transistors as the active amplifying circuit
    • H03F3/45636—Differential amplifiers with semiconductor devices only characterised by the way of common mode signal rejection in differential amplifiers with FET transistors as the active amplifying circuit by using feedback means
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F2200/00—Indexing scheme relating to amplifiers
    • H03F2200/372—Noise reduction and elimination in amplifier

Abstract

The invention discloses a chopping operational amplification circuit suitable for an infrared image CMOS sensor, and belongs to the technical field of integrated circuits. The circuit comprises: a first resistor R1A second resistance R2First stage preamplifier OP1A second stage amplifier OP2. First-stage preamplifier OP of the invention1The input tube of the circuit with the common-mode feedback double-input double-output folding cascode structure adopts a PMOS tube, so that 1/f noise can be effectively reduced; the output of the circuit is fed back to one end of the non-sensor signal input, so that the influence of the output resistance of the sensor on the closed-loop gain of the amplifier is reduced, and the problem of system stability caused by the fact that a feedback loop is directly connected with the input end connected with the sensor is avoided; the chopper operational amplification circuit can effectively inhibit 1/f noise, has higher sensitivity, and can be widely applied to non-contact measurement compared with the prior artTemperature, etc.

Description

Chopping operational amplification circuit suitable for infrared image CMOS sensor
Technical Field
The invention relates to a chopping operational amplification circuit suitable for an infrared image CMOS sensor, and belongs to the technical field of integrated circuits.
Background
1/f noise in CMOS circuits, also known as flicker noise, is a noise whose spectrum is concentrated in a low frequency band and is inversely proportional to frequency. The flicker noise is generated because of the boundary of the silicon single crystal at the interface of the gate oxide layer and the silicon substrate of the MOS transistor, and a number of dangling bonds are present, and some of the charge carriers are randomly trapped when flowing therethrough and then released, so that the current generates irregular fluctuation, which is the flicker noise. Since the sensor signal is basically in a low frequency band and the signal amplitude is small, the 1/f noise can seriously affect the signal quality and accurate measurement.
The prior art for reducing 1/f noise currently includes self-zeroing and chopping techniques.
The self-zeroing technique is a sampling technique that reduces 1/f noise by sampling low frequency noise and removing it from the instantaneous value of the signal. The process is an undersampling process of broadband white noise, so that white noise aliasing can be caused, the white noise of a low frequency band can be increased while 1/f noise is reduced, and in-band noise is larger, so that the self-zero-stabilizing technology is more suitable for a discrete signal circuit.
The chopping technique is a continuous-time method using modulation and demodulation methods. The principle is that the original input signal is modulated to high frequency, and the modulated signal is input into an operational amplifier for amplification. At this time, there is both signal and 1/f noise in the output of the operational amplifier. After demodulation, the modulated high frequency signal is restored to a low frequency and the noise is modulated to a high frequency. The noise may be filtered out by an external low pass filter. This technique is well suited for continuous-time microsensor interface circuits. However, the existing chopper operational amplifier mainly adopts a closed-loop double-end structure, and when the chopper operational amplifier feeds back from an output end to an input end, the chopper operational amplifier can affect the input end of a sensor, and the output resistance of the sensor can also affect the closed-loop gain of the amplifier.
Disclosure of Invention
In order to further inhibit noise and realize accurate amplification of signals, the invention provides a chopping operation amplifying circuit suitable for an infrared image CMOS sensor.
A first object of the present invention is to provide a closed-loop single-ended chopping operational amplifier circuit, comprising: a first resistor R1A second resistance R2A first chopper modulation switch, a second chopper modulation switch, and a first stage preamplifier OP1A second stage amplifier OP2Compensating electricityC, holding;
the first chopping modulation switch and the first-stage preamplifier OP1A second chopper-modulated switch, a second stage amplifier OP2Are connected in sequence; the first resistor R1Is connected with an external input, and the output end of the first chopper modulation switch is respectively connected with the first resistor R and the second resistor R2Connecting; the second resistor R2The input end is connected with the first resistor R1And the other end of the output terminal of (2) and the second-stage amplifier OP2The output ends of the two-way valve are connected; the second stage amplifier OP2The positive input end and the negative input end of the voltage regulator are respectively connected with a compensation capacitor;
the first chopping modulation switch is used for modulating an input signal to a chopping frequency; the first stage preamplifier OP1For amplifying the modulated signal; the second chopping modulation switch is used for demodulating the amplified signal to a baseband and modulating noise to an odd harmonic of chopping frequency; the first resistor R1And a second resistor R2For adjusting the amplification factor of the amplification circuit.
The first stage preamplifier OP1The internal structure of (a) includes: the input end of the common-mode feedback circuit is a PMOS (P-channel metal oxide semiconductor) tube.
Optionally, the circuit further includes: first input terminal In1And a second input terminal In2(ii) a The first input terminal In1A sensor signal connected to external input, and a second input terminal In2And the first resistor R1Is fed back to the second input terminal In2。
Optionally, the second stage amplifier OP2The method comprises the following steps: the double-input single-output folded cascode structure circuit.
Optionally, the overall amplification factor of the circuit is: r1+R2/R1。
Optionally, the internal circuit of the first chopper modulation switch includes clocks that are not overlapped in an inverted direction, and the frequency of the clocks is a chopping frequency.
Optionally, the second stage amplifier OP2Is lower than the gain of the first stage amplifier OP1The gain of (c).
A second object of the present invention is to provide a chopper operational amplifier, including: the chopper operational amplifier comprises an input end and an output end, and is characterized in that an internal circuit of the chopper operational amplifier comprises the closed-loop single-ended chopper operational amplifier circuit.
A third object of the present invention is to provide an infrared sensor measuring apparatus, comprising: the device comprises a black body, a sensor, an operational amplifier, a low-pass filter and a digital multimeter; the blackbody, the sensor, the operational amplifier, the low-pass filter and the digital multimeter are connected in sequence, and the operational amplifier is the chopping operational amplifier of claim 7.
Optionally, the sensor is: an infrared image CMOS sensor;
the positive output end of the infrared image CMOS sensor is connected with the first input end In1(ii) a The negative output end of the infrared image CMOS sensor is connected with the second input end In2。
Optionally, the working process of the device includes:
the infrared image CMOS sensor converts the thermal signal into an electric signal by utilizing a Seebeck effect;
the converted electric signal enters a chopping operational amplifier and outputs a noise signal modulated to a high frequency and a useful signal modulated to a low frequency;
the low-pass filter filters the output of the chopper operational amplifier to filter noise;
the digital multimeter measures the resulting output signal.
The invention has the beneficial effects that:
the chopping operational amplification circuit is provided with the first-stage preamplifier circuit which is a circuit with a common-mode feedback double-input double-output folding cascode structure, and the input tube adopts a PMOS tube, so that 1/f noise can be effectively reduced, and meanwhile, 1/f noise can be reduced by a chopping technology; the output of the chopping operational amplification circuit is fed back to one end of the non-sensor signal input, so that the influence of the output resistance of the sensor on the closed-loop gain of the amplifier is reduced, and the problem of system stability caused by the fact that a feedback loop is directly connected with the input end connected with the sensor is solved; in addition, the chopping operational amplification circuit finally modulates the useful signal to a low-frequency band and modulates the noise signal to a high-frequency band, thereby greatly facilitating the noise filtering in the subsequent signal processing, and achieving the effects of inhibiting low-frequency noise and realizing the accurate amplification of the signal.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
Fig. 1 is an overall circuit diagram of a closed-loop single-ended chopping operational amplifier according to an embodiment of the present invention.
Fig. 2 is a circuit diagram of a first stage preamplifier according to an embodiment of the invention.
Fig. 3 is a circuit diagram of a second stage amplifier according to an embodiment of the invention.
Fig. 4 is a circuit diagram of a chopper-modulated switch according to an embodiment of the present invention.
Fig. 5 is a schematic diagram of a connection of an infrared sensor measurement device according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
The first embodiment is as follows:
a closed-loop single-ended chopping operational amplification circuit, the circuit comprising: a first resistor R1A second resistance R2A first chopper modulation switch, a second chopper modulation switch, and a first stage preamplifier OP1A second stage amplifier OP2Compensating forA capacitor;
the first chopping modulation switch, the first-stage preamplifier OP1, the second chopping modulation switch and the second-stage amplifier OP2Are connected in sequence; the first resistor R1Is connected with an external input, and the output end of the first chopper modulation switch is respectively connected with the first resistor R and the second resistor R2Connecting; the second resistor R2The input end is connected with the first resistor R1And the other end is connected with the second stage amplifier OP2The output ends of the two-way valve are connected; the second stage amplifier OP2The positive input end and the negative input end of the voltage regulator are respectively connected with a compensation capacitor; the second stage amplifier OP2Is fed back to the first resistor R1To the input terminal of (1).
The first chopping modulation switch is used for modulating an input signal to a chopping frequency; the first stage preamplifier OP1For amplifying the modulated signal; the second chopper modulation switch is used for demodulating the amplified signal to a baseband; the amplifier is used for amplifying the demodulated signal; the first resistor R1And a second resistor R2For adjusting the amplification factor of the amplification circuit.
The first stage preamplifier OP1The internal structure of (a) includes: the input end of the common-mode feedback circuit is a PMOS (P-channel metal oxide semiconductor) tube.
The chopping operational amplification circuit of the embodiment is provided with the first-stage pre-amplification circuit, the first-stage pre-amplification circuit is a circuit with a common-mode feedback double-input double-output folding cascode structure, the input tube adopts a PMOS tube, and 1/f noise can be effectively reduced, so that the chopping operational amplification circuit of the embodiment has good noise suppression performance, the output of the chopping operational amplification circuit is fed back to one end of a non-sensor signal input, the influence of a sensor output resistor on the closed-loop gain of an amplifier is reduced, and the problem of system stability caused by the fact that a feedback loop is directly connected with an input end connected with a sensor is avoided.
Example two
The embodiment provides a closed-loop single endAs shown in fig. 1, the chopper operational amplifier circuit includes: a first resistor R1A second resistance R2A first chopper modulation switch, a second chopper modulation switch, and a first stage preamplifier OP1A second stage amplifier OP2And a compensation capacitor C1And C2；
The internal circuit structure of the first chopper-modulated switch and the second chopper-modulated switch is shown in fig. 4, and includes two input terminals (vin and vip), two output terminals (voutn and voutp), clka and clkb are two clocks with non-overlapping inverted phases, and the frequency of the clocks is the chopping frequency.
First stage preamplifier OP1The internal circuit of (2) is shown in fig. 2, and has two input ends (1, 2) and two output ends (3, 4), and comprises a double-input double-output folded cascode operational amplification circuit and a common-mode feedback circuit with a single-stage amplifier structure. Bias voltage (V)b1、Vb2And Vb3) Given by a bias circuit, VcmIs the common mode voltage.
Second stage amplifier OP2The internal circuit of (2) is shown in figure 3, and comprises two input ends (5, 6) and an output end (7), and a double-input single-output folded cascode structure is adopted in the internal circuit. Bias voltage (V)b1、Vb2、Vb3And Vb4) Given by the bias circuit. The gain of the second stage amplifier is slightly lower than that of the first stage amplifier.
Output voltage of sensor from In1And In2End input, R0For the output resistance of the sensor, firstly, the input signal is modulated to the chopping frequency through a first chopping modulation switch; the output modulated signal is then passed from the first stage preamplifier OP1The serial numbers of the input ports 1 and 2 are output from the serial numbers of the input ports 3 and 4, and the operational amplifier can introduce imbalance and 1/f noise while amplifying signals; OP (optical fiber)1The output signal enters a switch of a second chopping modulator, the preliminarily amplified signal is demodulated to a baseband, and a noise signal is modulated to an odd harmonic of a chopping frequency; finally, the output signal of the second chopper modulator switch is taken from OP2Are inputted from the ports numbered 5 and 6, the signal is further amplified, and the signal is inputted from the end numbered 7The output is carried out through the interface, useful signals in the output signals are in a low frequency band, noise signals are modulated to a high frequency band, and subsequent noise signals are conveniently filtered.
OP2That is, the final output signal of the chopper amplification circuit of the present embodiment, which is fed back to In2Terminal without direct feedback to the sensor signal input terminal In1And the problem of system stability caused by direct connection of a feedback loop and an input end connected with a sensor is solved.
The chopping operational amplification circuit of the embodiment is provided with the first-stage preamplifier circuit which is a circuit with a common-mode feedback double-input double-output folding cascode structure, the input tube adopts a PMOS tube, 1/f noise can be effectively reduced, and thermal noise can be inhibited by the folding input stage and the PMOS differential pair; the output of the chopping operational amplification circuit is fed back to one end of the non-sensor signal input, so that the influence of the output resistance of the sensor on the closed-loop gain of the amplifier is reduced, and the problem of system stability caused by the fact that a feedback loop is directly connected with the input end connected with the sensor is solved; in addition, the chopping operational amplification circuit finally modulates the useful signal to a low-frequency band and modulates the noise signal to a high-frequency band, thereby greatly facilitating the noise filtering in the subsequent signal processing, and achieving the effects of inhibiting low-frequency noise and realizing the accurate amplification of the signal.
EXAMPLE III
The present embodiment provides an infrared sensor measuring apparatus, including: the device comprises a black body, an infrared image CMOS sensor, an operational amplifier, a low-pass filter and a digital multimeter; the black body, the infrared image CMOS sensor, the operational amplifier, the low-pass filter and the digital multimeter are sequentially connected, the operational amplifier is the chopping operational amplifier provided by the invention, and the internal circuit of the chopping operational amplifier is the circuit with the structure provided by the second embodiment.
The positive output end of the infrared image CMOS sensor is connected with the input end In of the chopping operational amplifier1The negative output end is connected with the input end In of the chopper operational amplifier2And a common mode voltage VcmOutput terminal of chopper operational amplifier7 is connected with a low-pass filter and simultaneously feeds back signals to In2And (4) an end.
The black body is used as an infrared radiation source, and the temperature is controlled by a black body controller. The infrared image CMOS sensor converts a thermal signal into an electrical signal using the seebeck effect. The ambient temperature around the sensor is controlled by an incubator. The converted electrical signal is amplified by a chopping operational amplifier, and the amplifier shows ideal linear performance while suppressing noise. Since the final noise is modulated to a high frequency and the signal is at a low frequency, the noise can be filtered out using an external low pass filter. The output of the system was measured using a digital multimeter.
In this embodiment, the resistance (R) in the circuit is changed1And R2) The amplification factor of the operational amplifier can be simply and conveniently set according to the size or the proportional relation.
Simulation results show that the input equivalent noise density of a chopper operational amplifier at 200Hz is
Figure BDA0003324505530000061
The sensitivity of the apparatus of this embodiment (including the sensor and amplifier) was about 15 mV/deg.C when the gain was set to 40dB and the distance between the sensor and the target object was 3 cm. Therefore, the infrared sensor measuring equipment of the embodiment has good noise suppression performance and high sensitivity, and has wider application prospect in the special application fields of non-contact temperature measurement and the like compared with the temperature measuring equipment adopting the closed-loop double-end structure operational amplifier in the prior art.
Some steps in the embodiments of the present invention may be implemented by software, and the corresponding software program may be stored in a readable storage medium, such as an optical disc or a hard disk.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims (10)

1. A closed-loop single-ended chopping operational amplification circuit is characterized in that the circuitThe method comprises the following steps: a first resistor R1A second resistance R2A first chopper modulation switch, a second chopper modulation switch, and a first stage preamplifier OP1A second stage amplifier OP2The compensation capacitor;
the first chopping modulation switch and the first-stage preamplifier OP1A second chopper-modulated switch, a second stage amplifier OP2Are connected in sequence; the first resistor R1Is connected with an external input, and the output end of the first chopper modulation switch is respectively connected with the first resistor R and the second resistor R2Connecting; the second resistor R2The input end is connected with the first resistor R1And the other end of the output terminal of (2) and the second-stage amplifier OP2The output ends of the two-way valve are connected; the second stage amplifier OP2The positive input end and the negative input end of the voltage regulator are respectively connected with a compensation capacitor;
the first chopping modulation switch is used for modulating an input signal to a chopping frequency; the first stage preamplifier OP1For amplifying the modulated signal; the second chopping modulation switch is used for demodulating the amplified signal to a baseband and modulating noise to an odd harmonic of chopping frequency; the first resistor R1And a second resistor R2The amplification factor of the amplifying circuit is adjusted;
the first stage preamplifier OP1The internal structure of (a) includes: the input end of the common-mode feedback circuit is a PMOS (P-channel metal oxide semiconductor) tube.
2. The circuit of claim 1, further comprising: first input terminal In1And a second input terminal In2(ii) a The first input terminal In1Receiving sensor signals input from outside; the second input terminal In2And the first resistor R1Is fed back to the second input terminal In2。
3. The circuit of claim 1, wherein the circuit is configured to operate in a synchronous mannerThe second stage amplifier OP2The method comprises the following steps: the double-input single-output folded cascode structure circuit.
4. The circuit of claim 1, wherein the overall amplification of the circuit is: r1+R2/R1。
5. The circuit of claim 1, wherein the internal circuitry of the first chopper-modulated switch includes inverted non-overlapping clocks having a chopping frequency.
6. The circuit of claim 1, wherein the gain of the second stage amplifier OP2 is lower than the gain of the first stage amplifier OP1The gain of (c).
7. A chopping operational amplifier, comprising: input terminal, output terminal, characterized in that the internal circuitry of the chopping operational amplifier comprises a closed-loop single-ended chopping operational amplification circuit according to any of claims 1-6.
8. An infrared sensor measurement device comprising: the device comprises a black body, a sensor, an operational amplifier, a low-pass filter and a digital multimeter; the blackbody, the sensor, the operational amplifier, the low-pass filter and the digital multimeter are connected in sequence, and the operational amplifier is the chopping operational amplifier of claim 7.
9. The apparatus of claim 8, wherein the sensor is: an infrared image CMOS sensor.
10. The apparatus of claim 9, wherein the operation of the apparatus comprises:
the infrared image CMOS sensor converts the thermal signal into an electric signal by utilizing a Seebeck effect;
the converted electric signal enters a chopping operational amplifier and outputs a noise signal modulated to a high frequency and a useful signal modulated to a low frequency;
the low-pass filter filters the output of the chopper operational amplifier to filter noise;
the digital multimeter measures the resulting output signal.
CN202111257325.4A 2021-10-27 2021-10-27 Chopping operational amplification circuit suitable for infrared image CMOS sensor Pending CN113965172A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202111257325.4A CN113965172A (en) 2021-10-27 2021-10-27 Chopping operational amplification circuit suitable for infrared image CMOS sensor

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202111257325.4A CN113965172A (en) 2021-10-27 2021-10-27 Chopping operational amplification circuit suitable for infrared image CMOS sensor

Publications (1)

Publication Number Publication Date
CN113965172A true CN113965172A (en) 2022-01-21

Family

ID=79467602

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202111257325.4A Pending CN113965172A (en) 2021-10-27 2021-10-27 Chopping operational amplification circuit suitable for infrared image CMOS sensor

Country Status (1)

Country Link
CN (1) CN113965172A (en)

Similar Documents

Publication Publication Date Title
US5084639A (en) Low frequency noise canceling photodetector preamplifier useful for computerized tomography
US7589587B2 (en) Feedback amplifier circuit operable at low voltage by utilizing switched operational amplifier and chopper modulator
CN110417360B (en) Low-noise amplifier for bioelectricity detection
CN103095233B (en) The amplifier of cancellation of DC offset
CN104931077B (en) Circuit for reducing residual offset of integrated hall sensor
CN111628735B (en) High-precision linear Hall sensor reading circuit
CN103414442A (en) High-precision fully differential amplifier based on chopper technology
US7477109B2 (en) Process and temperature-compensated transimpedance amplifier
Jiang et al. 11.3 A hybrid multipath CMOS magnetic sensor with 210µTrms resolution and 3MHz bandwidth for contactless current sensing
Hsu et al. Design of low-frequency low-pass filters for biomedical applications
Drung et al. Improved direct-coupled dc SQUID read-out electronics with automatic bias voltage tuning
CN107294497B (en) Conversion circuit, heartbeat current signal conversion device and method and heartbeat detection system
Jiang et al. A multi-path CMOS Hall sensor with integrated ripple reduction loops
CN113965172A (en) Chopping operational amplification circuit suitable for infrared image CMOS sensor
US11114991B2 (en) Analog front-end circuit for conditioning a sensor signal
TW202324911A (en) Analog signal processing circuit and direct current offset voltage elimination method
CN105680805B (en) A kind of dc-couple high-precision amplification device
CN106026938A (en) Fully differential comparator
CN111969963B (en) Pre-amplifier
CN114915267A (en) Single-end-to-differential microphone circuit and electronic equipment
Kolm et al. A 3rd-order 235MHz low-pass gmC-filter in 120nm CMOS
Zheng et al. A low-power chopper bandpass amplifier for biopotential sensors
CN118033209A (en) Dual-channel broadband Hall current sensor and implementation method
CN203039646U (en) High-performance operational amplifier
CN117405952A (en) Hall signal processing circuit, hall signal processing device and Hall sensor

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination