CN112217480A - Trans-impedance amplifier based on capacitor feedback and photoelectric sensor - Google Patents
Trans-impedance amplifier based on capacitor feedback and photoelectric sensor Download PDFInfo
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- CN112217480A CN112217480A CN201910726174.9A CN201910726174A CN112217480A CN 112217480 A CN112217480 A CN 112217480A CN 201910726174 A CN201910726174 A CN 201910726174A CN 112217480 A CN112217480 A CN 112217480A
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- 239000003990 capacitor Substances 0.000 title claims abstract description 44
- 230000003321 amplification Effects 0.000 claims abstract description 9
- 238000003199 nucleic acid amplification method Methods 0.000 claims abstract description 9
- 238000004519 manufacturing process Methods 0.000 abstract description 6
- 230000003071 parasitic effect Effects 0.000 abstract description 5
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- 238000004458 analytical method Methods 0.000 description 1
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- 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
- H03F1/34—Negative-feedback-circuit arrangements with or without positive feedback
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Abstract
The invention discloses a capacitor feedback-based trans-impedance amplifier and a photoelectric sensor, wherein the trans-impedance amplifier comprises a photoelectric sensor and a signal amplification circuit for amplifying the output current of the photoelectric sensor, the signal amplification circuit is a trans-impedance amplifier, and a negative feedback circuit of the trans-impedance amplifier is composed of a feedback capacitor. The parasitic resistance of the capacitor is used for replacing a resistor required by the capacitor, so that the problems of high price and high production difficulty of a large resistor are avoided, and the cost is reduced.
Description
Technical Field
The invention relates to the field of transimpedance amplifiers, in particular to a transimpedance amplifier and a photoelectric sensor based on capacitor feedback.
Background
A photoelectric sensor is a device that converts an optical signal into an electrical signal, and its operating principle is based on the photoelectric effect. The photoelectric effect refers to the phenomenon that when light irradiates on some substances, electrons of the substances absorb the energy of photons, and the corresponding electric effect occurs. In the application of a common photoelectric sensor, a trans-impedance amplifier is generally adopted to amplify the output of the photoelectric sensor, the feedback resistor of the trans-impedance amplifier is generally in the level from K omega to M omega and belongs to a conventional resistance device, the device process and the application of the trans-impedance amplifier belong to a mature conventional process, and a circuit is easy to realize and stably work. However, in some high-demand applications of photosensors, amplification of weak photocurrent at the fA level is required. Due to the characteristics of the transimpedance amplifier, it is not possible to use the commonly used voltage amplification means such as multi-stage amplification in order to achieve the highest signal-to-noise ratio. At this time, the current needs to be trans-resistance amplified by adopting the feedback resistance value of G omega level once so as to obtain the output voltage signal with the highest signal-to-noise ratio. Since the resistor of this class is expensive, the precision and stability are inferior to those of the mature resistor of the ordinary resistance range, and if the purpose of establishing the feedback loop is achieved by using the resistor of G omega class, the cost is high.
Disclosure of Invention
The present invention provides a transimpedance amplifier and a photoelectric sensor based on capacitor feedback to solve the above technical problems.
The invention is realized by the following technical scheme:
a trans-impedance amplifier based on capacitor feedback comprises an operational amplifier and a negative feedback circuit connected to the operational amplifier, wherein the negative feedback circuit is composed of a feedback capacitor. The inventor creatively utilizes the leakage current characteristic of a common capacitor in the research and development process, and the capacitor is used as a resistance feedback device of a feedback loop in a feedback resistance trans-impedance amplifier with large resistance value to replace an expensive resistance device, so that the stability and the highest signal-to-noise ratio of the photoelectric sensor can be realized, and the lower cost can be realized. The leakage current of the feedback capacitor belongs to the fA level, the resistance value of the generated equivalent large resistor is about 100G, meanwhile, the leakage current of the feedback capacitor is equal to that of a 100G resistor and a 100G capacitor which are manufactured in parallel in an actual device, the requirement of a feedback loop on the resistor is met, the requirement of circuit stability on a compensation capacitor is also met, and the manufacturing process and the circuit volume of the sensor device are greatly simplified.
A trans-impedance amplifier based on capacitor feedback comprises an operational amplifier and a negative feedback circuit connected to the operational amplifier, wherein the output current of a photoelectric sensor is less than 1pA, and the negative feedback circuit comprises a feedback capacitor connected between the output end and the inverting input end of the operational amplifier. Different capacitors have different leakage currents and different capacitance parameters, and the requirement for different device parameters needs to be considered when a single capacitor is applied to a specific transimpedance amplifier circuit. The resistance of the existing trans-impedance amplifier is used for determining the feedback size, and the capacitance is used as a loop compensation element to improve the loop stability of the system. The inventor finally finds a proper capacitor capable of meeting the performance requirement of the current trans-impedance amplifier through the acquisition and analysis of a large amount of experimental data, the leakage current of the feedback capacitor is fa level, an equivalent large resistor can be generated to serve as the feedback resistor, and the proper capacitance value can be possessed to improve the stability of a system loop. The parasitic resistance of the capacitor is used for replacing a resistor needed by the capacitor, so that the problems of high price and high production difficulty of a large resistor are avoided, and the cost is reduced.
Compared with the prior art, the invention has the following advantages and beneficial effects:
1. the trans-impedance amplifier of the invention utilizes the parasitic resistance of the capacitor to replace the resistor required by the trans-impedance amplifier, thereby avoiding the problems of high price and high production difficulty of a large resistor and reducing the cost.
2. The signal amplification circuit of the photoelectric sensor adopts the transimpedance amplifier, so that the stability and the highest signal-to-noise ratio of the photoelectric sensor can be realized, and the lower cost can be realized.
Drawings
The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention.
Fig. 1 is a schematic circuit diagram of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to examples and accompanying drawings, and the exemplary embodiments and descriptions thereof are only used for explaining the present invention and are not meant to limit the present invention.
Example 1
The transimpedance amplifier based on the capacitor feedback shown in fig. 1 is suitable for an application scene with ultrahigh gain, and comprises an operational amplifier and a negative feedback circuit connected to the operational amplifier, wherein the negative feedback circuit comprises a feedback capacitor connected between an output end and an inverting input end of the operational amplifier. By adopting the transimpedance amplifier of the present embodiment, the equivalent parasitic resistance of the actual capacitor is used as the feedback large resistance of the high-gain transimpedance amplifier. Through a large number of practical experiments and device screening, practical capacitor devices meeting circuit requirements are found. By adopting the transimpedance amplifier of the scheme, although the performance of the amplification linearity of the amplifying circuit is compromised, other main performances of the circuit are improved, the signal-to-noise ratio of the circuit even exceeds that of the traditional resistor feedback circuit, and the cost of manufacturing raw materials of the circuit is greatly reduced. In a common trans-impedance amplifier of a K Ω to M Ω level, the cost of the feedback resistor is only a few cents; in a trans-impedance amplifier in an ultra-high gain application scene, the price of a feedback resistor is up to dozens of resistors; the cost of the trans-impedance amplifier adopting the scheme can be reduced to be the same as that of a common trans-impedance amplifier.
The leakage current of the feedback capacitor is fa level, the resistance value of the generated equivalent large resistor is between 50G ohm and 200G ohm, the equivalent large resistor can be generated to serve as the feedback resistor, and the feedback capacitor can have a proper capacitance value to improve the stability of a system loop. Generally, the capacitance of the feedback capacitor is between 0.1pf and 10pf, preferably between 0.5pf and 2, which can meet the requirements of the feedback loop on the resistance and the circuit stability on the compensation capacitor.
It should be noted that the capacitor is not a resistor, and the resistance of the equivalent resistor changes with the change of the signal frequency. That is, the linearity of the equivalent resistance of the capacitor is much worse than that of the real resistor, and the specific influence is that the equivalent resistance of the capacitor is large and the amplitude of the output voltage is large at low frequency signals, and the equivalent resistance is small at high frequency signals. The amplitude of the output voltage is small. Resulting in a reduced linearity of the signal. However, in some transimpedance amplifier application examples, the photoelectric signal is only used as a detection signal for judging whether a target exists or not, and is not sensitive to the linearity distortion of the signal in a frequency domain. This difference in performance does not affect the application.
Example 2
Based on the transimpedance amplifier of the embodiment, the embodiment discloses a specific application example.
Specifically, a current input end of the photoelectric sensor is connected with a negative input end of an operational amplifier, the other end of a current output end is connected with a positive input end of the operational amplifier, and the positive input end of the operational amplifier is used as a reference voltage point. The parasitic resistance value and the capacitance value of the chip capacitor MLCC form a feedback resistor Rfb and a feedback capacitor Cfb which are required by the circuit, and the feedback resistor Rfb and the feedback capacitor Cfb are connected between the output end and the negative input end of the operational amplifier to form a feedback loop. The feedback resistor is used for determining the gain of the trans-impedance amplifier, and the output voltage of the circuit is equal to the input current multiplied by the resistance value of the feedback resistor. When the structure of the embodiment is adopted to amplify the fA level weak photocurrent, the requirements of the circuit on the ultrahigh-gain feedback resistance value and the requirements of the circuit stability on the compensation capacitor are met, and the manufacturing process and the circuit volume of the sensor device are greatly simplified.
The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (4)
1. A trans-impedance amplifier based on capacitor feedback comprises an operational amplifier and a negative feedback circuit connected to the operational amplifier, and is characterized in that the negative feedback circuit is composed of a feedback capacitor.
2. The transimpedance amplifier according to claim 1, wherein the capacitance of the feedback capacitor is between 0.1pf and 10 pf.
3. The transimpedance amplifier according to claim 1, wherein the capacitance of the feedback capacitor is between 0.5pf and 2.
4. A photosensor comprising a photosensor and a signal amplification circuit for amplifying the photosensor output current, said photosensor output current being less than 1pA, wherein said signal amplification circuit is the transimpedance amplifier of any of claims 1-3.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910726174.9A CN112217480A (en) | 2019-08-07 | 2019-08-07 | Trans-impedance amplifier based on capacitor feedback and photoelectric sensor |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201910726174.9A CN112217480A (en) | 2019-08-07 | 2019-08-07 | Trans-impedance amplifier based on capacitor feedback and photoelectric sensor |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113517864A (en) * | 2021-07-26 | 2021-10-19 | 成都优蕊光电科技有限公司 | Transimpedance amplifier based on diode feedback and photoelectric sensor |
| CN113541610A (en) * | 2021-07-26 | 2021-10-22 | 成都优蕊光电科技有限公司 | Transimpedance amplifier and infrared sensor based on parasitic parameter feedback of printed circuit board |
| CN113702947A (en) * | 2021-08-09 | 2021-11-26 | 北京一径科技有限公司 | Transimpedance amplifier, light receiving device and laser radar receiver |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4868902A (en) * | 1988-02-03 | 1989-09-19 | Hughes Aircraft Company | GaAs capacitive feedback transimpedance amplifier |
| US5982232A (en) * | 1998-04-01 | 1999-11-09 | International Business Machines Corporation | Low noise, bandwidth compensated transimpedance amplifier |
| US20090224827A1 (en) * | 2008-03-06 | 2009-09-10 | Preetam Charan Anand Tadeparthy | Split-feedback Technique for Improving Load Regulation in Amplifiers |
| CN102375900A (en) * | 2010-08-19 | 2012-03-14 | 上海华虹Nec电子有限公司 | Radio-frequency metal-insulator-metal (MIM) capacitor simulation circuit structure taking skin effect into consideration |
| CN102506903A (en) * | 2011-10-18 | 2012-06-20 | 山东华翼微电子技术有限责任公司 | Photoelectric detection circuit |
| CN202307876U (en) * | 2011-08-11 | 2012-07-04 | 沈阳中科微电子有限公司 | MIM capacitor |
| US20130341192A1 (en) * | 2011-07-20 | 2013-12-26 | The Regents Of The University Of California | Compensated patch-clamp amplifier for nanopore polynucleotide sequencing and other applications |
-
2019
- 2019-08-07 CN CN201910726174.9A patent/CN112217480A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4868902A (en) * | 1988-02-03 | 1989-09-19 | Hughes Aircraft Company | GaAs capacitive feedback transimpedance amplifier |
| US5982232A (en) * | 1998-04-01 | 1999-11-09 | International Business Machines Corporation | Low noise, bandwidth compensated transimpedance amplifier |
| US20090224827A1 (en) * | 2008-03-06 | 2009-09-10 | Preetam Charan Anand Tadeparthy | Split-feedback Technique for Improving Load Regulation in Amplifiers |
| CN102375900A (en) * | 2010-08-19 | 2012-03-14 | 上海华虹Nec电子有限公司 | Radio-frequency metal-insulator-metal (MIM) capacitor simulation circuit structure taking skin effect into consideration |
| US20130341192A1 (en) * | 2011-07-20 | 2013-12-26 | The Regents Of The University Of California | Compensated patch-clamp amplifier for nanopore polynucleotide sequencing and other applications |
| CN202307876U (en) * | 2011-08-11 | 2012-07-04 | 沈阳中科微电子有限公司 | MIM capacitor |
| CN102506903A (en) * | 2011-10-18 | 2012-06-20 | 山东华翼微电子技术有限责任公司 | Photoelectric detection circuit |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113517864A (en) * | 2021-07-26 | 2021-10-19 | 成都优蕊光电科技有限公司 | Transimpedance amplifier based on diode feedback and photoelectric sensor |
| CN113541610A (en) * | 2021-07-26 | 2021-10-22 | 成都优蕊光电科技有限公司 | Transimpedance amplifier and infrared sensor based on parasitic parameter feedback of printed circuit board |
| CN113541610B (en) * | 2021-07-26 | 2023-07-07 | 成都优蕊光电科技有限公司 | Transimpedance amplifier and infrared sensor based on parasitic parameter feedback of printed circuit board |
| CN113702947A (en) * | 2021-08-09 | 2021-11-26 | 北京一径科技有限公司 | Transimpedance amplifier, light receiving device and laser radar receiver |
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