CN219697610U - Operational amplifier circuit - Google Patents
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- CN219697610U CN219697610U CN202320853825.2U CN202320853825U CN219697610U CN 219697610 U CN219697610 U CN 219697610U CN 202320853825 U CN202320853825 U CN 202320853825U CN 219697610 U CN219697610 U CN 219697610U
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- 239000003990 capacitor Substances 0.000 claims description 56
- 238000001914 filtration Methods 0.000 abstract description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 8
- 229910052799 carbon Inorganic materials 0.000 description 6
- 238000010586 diagram Methods 0.000 description 5
- 230000003321 amplification Effects 0.000 description 4
- 238000003199 nucleic acid amplification method Methods 0.000 description 4
- 239000004615 ingredient Substances 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 239000002041 carbon nanotube Substances 0.000 description 1
- 229910021393 carbon nanotube Inorganic materials 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 229910021389 graphene Inorganic materials 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 1
- 229910010271 silicon carbide Inorganic materials 0.000 description 1
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Abstract
The utility model provides an operational amplifier circuit, comprising: the first-stage operational amplifier circuit, the second-stage operational amplifier circuit, the third-stage operational amplifier circuit and the fourth-stage operational amplifier circuit; the first-stage operational amplifier circuit is used for amplifying a small current signal of the nA stage output by the current type sensor into a voltage signal of the mV stage; the second-stage operational amplifier circuit is used for limiting amplitude-frequency distortion of the amplified signal output by the first-stage operational amplifier circuit; the third-stage operational amplifier circuit and the fourth-stage operational amplifier circuit are used for filtering signals output by the second-stage operational amplifier circuit. The operational amplifier circuit provided by the utility model can amplify the nA-level current signal and has the characteristics of high precision, low noise and low nonlinearity.
Description
Technical Field
The utility model belongs to the technical field of electronic circuit technique and specifically relates to an operational amplifier circuit.
Background
The carbon-based chip is a chip taking carbon nano tubes, silicon carbide graphene and other materials as cores. Compared with a conventional silicon-based chip, the performance of the carbon-based chip is improved by more than 10 times, and the carbon-based chip has better electronic characteristics, such as faster transmission rate. Therefore, carbon-based chips are widely used in a variety of technical fields.
In the field of biotechnology, the carbon-based biosensor chip is a amperometric sensor, and its output current varies with the change of the sample to be detected, so that the type of the sample to be detected can be determined according to the time-current characteristics of the sample to be detected, so as to realize further analysis. The maximum value of the output current of the carbon-based biological sensing chip is 2.5uA, the output current is generally 10 nA-300 nA in normal operation, the current signal is smaller, the output current cannot be directly processed and applied by the A/D converter, and the conventional operational amplifier circuit has low precision and high noise.
Disclosure of Invention
In view of this, the embodiment of the utility model provides an operational amplifier circuit to eliminate or improve one or more defects existing in the prior art, and solve the problems that the current type sensor outputs a small current signal, cannot be directly processed and applied by an a/D converter, and the existing operational amplifier circuit has low precision and high noise.
The technical scheme of the utility model is as follows:
the utility model provides an operational amplifier circuit, which is characterized by comprising:
a first stage operational amplifier circuit; the positive input end of the first-stage operational amplifier circuit is connected with direct-current voltage, and the negative input end of the first-stage operational amplifier circuit is connected with a current type sensor; the first capacitor is connected across the reverse input end and the output end of the first-stage operational amplifier circuit; the first resistor is connected with the reverse input end of the first-stage operational amplifier circuit in a bridging way and the second resistor; the second resistor is connected in series with the output end of the first-stage operational amplifier circuit and is connected with the first capacitor and the first resistor;
a second-stage operational amplifier circuit; the positive input end of the second-stage operational amplifier circuit is connected with direct-current voltage, and the reverse input end of the second-stage operational amplifier circuit is connected with the output end of the first-stage operational amplifier circuit through a second resistor and a third resistor which are connected in series; the fourth resistor is connected across the reverse input end and the output end of the second-stage operational amplifier circuit;
a third-stage operational amplifier circuit; the positive input end of the third-stage operational amplifier circuit is connected with the output end of the second-stage operational amplifier circuit through a fifth resistor and a sixth resistor which are connected in series, and the reverse input end of the third-stage operational amplifier circuit is connected with a third capacitor; the third capacitor is connected with the output ends of the sixth resistor and the third-stage operational amplifier circuit in a bridging way; the positive input end of the third-stage operational amplifier circuit is connected in series with a fourth capacitor for grounding;
a fourth-stage operational amplifier circuit; the positive input end of the fourth-stage operational amplifier circuit is connected with the output end of the third-stage operational amplifier circuit through a seventh resistor and an eighth resistor which are connected in series, and the reverse input end of the fourth-stage operational amplifier circuit is connected with a fifth capacitor; the fifth capacitor is connected with the eighth resistor and the output end of the fourth-stage operational amplifier circuit in a bridging way; and the positive input end of the fourth-stage operational amplifier circuit is connected with a sixth capacitor in series for grounding.
In some embodiments of the utility model, the first stage operational amplifier circuit is a transimpedance amplifier circuit.
In some embodiments of the present utility model, the positive input terminals of the first stage operational amplifier circuit and the second stage operational amplifier circuit are connected with a direct current voltage of 2.5V.
In some embodiments of the utility model, the second stage operational amplifier circuit is an operational amplifier circuit that limits amplitude-frequency distortion.
In some embodiments of the present utility model, in the second-stage operational amplifier circuit, the first resistor is connected in series with a second capacitor to perform grounding, so as to filter the voltage ripple output by the first-stage operational amplifier circuit.
In some embodiments of the present utility model, the third resistor and the fourth resistor have equal resistance values to maintain the gain of the second stage operational amplifier circuit at 1.
In some embodiments of the present utility model, the third stage operational amplifier circuit and the fourth stage operational amplifier circuit form a second order SK type low pass filter to reduce noise interference of the first stage operational amplifier circuit and the second stage operational amplifier circuit.
In some embodiments of the present utility model, in the third stage operational amplifier circuit, the resistance values of the fifth resistor, the sixth resistor, and the capacitance values of the third capacitor and the fourth capacitor are determined by gain bandwidths of the first stage operational amplifier circuit.
In some embodiments of the present utility model, in the fourth stage operational amplifier circuit, the resistance values of the seventh resistor, the eighth resistor, and the capacitance values of the fifth capacitor and the sixth capacitor are determined by the gain bandwidth of the first stage operational amplifier circuit.
In some embodiments of the present utility model, the first capacitance value is set to 20pF, the first resistance value is set to 100 Ω, and the second resistance value is set to 1mΩ, so as to amplify a nA-level current signal input at the positive input terminal of the first-stage operational amplifier circuit into a mV-level voltage signal.
The utility model has the advantages that:
the utility model provides a high-precision low-noise operational amplifier circuit, which comprises a first-stage operational amplifier circuit, a second-stage operational amplifier circuit, a third-stage operational amplifier circuit and a fourth-stage operational amplifier circuit; the first-stage operational amplifier circuit is used for amplifying a small current signal of the nA stage output by the current type sensor into a voltage signal of the mV stage; the second-stage operational amplifier circuit is used for limiting amplitude-frequency distortion of the amplified signal output by the first-stage operational amplifier circuit; the third-stage operational amplifier circuit and the fourth-stage operational amplifier circuit are used for filtering signals output by the second-stage operational amplifier circuit. The operational amplifier circuit provided by the utility model can amplify the output signal of the nA-level current type sensor to a signal range which can be acquired by the A/D converter, and the processed signal has the characteristics of high precision, low noise and low nonlinearity.
Additional advantages, objects, and features of the utility model will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the utility model. The objectives and other advantages of the utility model may be realized and attained by the structure particularly pointed out in the written description and drawings thereof.
It will be appreciated by those skilled in the art that the objects and advantages that can be achieved with the present utility model are not limited to the above-described specific ones, and that the above and other objects that can be achieved with the present utility model will be more clearly understood from the following detailed description.
Drawings
The accompanying drawings, which are included to provide a further understanding of the utility model and are incorporated in and constitute a part of this specification, illustrate and together with the description serve to explain the utility model. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the utility model. Corresponding parts in the drawings may be exaggerated, i.e. made larger relative to other parts in an exemplary device actually manufactured according to the present utility model, for convenience in showing and describing some parts of the present utility model. In the drawings:
fig. 1 is a schematic diagram of an operational amplifier circuit according to an embodiment of the utility model.
Fig. 2 is a schematic diagram of the first-stage operational amplifier circuit and the second-stage operational amplifier circuit according to an embodiment of the utility model.
Fig. 3 is a schematic diagram of the third-stage op-amp circuit and the fourth-stage op-amp circuit according to an embodiment of the present utility model.
FIG. 4 is a schematic diagram of an operational amplifier circuit including implementation parameters according to an embodiment of the present utility model.
Reference numerals illustrate:
100: a first stage operational amplifier circuit; 200: a second-stage operational amplifier circuit;
300: a third-stage operational amplifier circuit; 400: a fourth-stage operational amplifier circuit;
101: the forward input end of the first-stage operational amplifier circuit; 102: the reverse input end of the first-stage operational amplifier circuit;
103: the output end of the first-stage operational amplifier circuit; 104: a first capacitor;
105: a first resistor; 106: a second resistor;
201: a positive input end of the second-stage operational amplifier circuit; 202: the reverse input end of the second-stage operational amplifier circuit;
203: the output end of the second-stage operational amplifier circuit; 204: a third resistor;
205: a fourth resistor; 301: the positive input end of the third-stage operational amplifier circuit;
302: the reverse input end of the third-stage operational amplifier circuit; 303: the output end of the second-stage operational amplifier circuit;
304: a fifth resistor; 305: a sixth resistor;
306: a third capacitor; 401: a positive input end of the fourth-stage operational amplifier circuit;
402: the reverse input end of the fourth-stage operational amplifier circuit; 403: the output end of the fourth-stage operational amplifier circuit;
404: a seventh resistor; 405: an eighth resistor;
406: and a sixth capacitor.
Detailed Description
The present utility model will be described in further detail with reference to the following embodiments and the accompanying drawings, in order to make the objects, technical solutions and advantages of the present utility model more apparent. The exemplary embodiments of the present utility model and the descriptions thereof are used herein to explain the present utility model, but are not intended to limit the utility model.
It should be noted here that, in order to avoid obscuring the present utility model due to unnecessary details, only structures and/or processing steps closely related to the solution according to the present utility model are shown in the drawings, while other details not greatly related to the present utility model are omitted.
It should be emphasized that the term "comprises/comprising" when used herein is taken to specify the presence of stated features, elements, steps or components, but does not preclude the presence or addition of one or more other features, elements, steps or components.
It is also noted herein that the term "coupled" may refer to not only a direct connection, but also an indirect connection in which an intermediate is present, unless otherwise specified.
Hereinafter, embodiments of the present utility model will be described with reference to the accompanying drawings. In the drawings, the same reference numerals represent the same or similar components, or the same or similar steps.
In order to solve the problem that the current sensor outputs a small current signal, which cannot be directly processed and applied by the a/D converter, and the existing operational amplifier circuit has low precision and high noise, the utility model provides an operational amplifier circuit, as shown in fig. 1, which comprises a first-stage operational amplifier circuit 100, a second-stage operational amplifier circuit 200, a third-stage operational amplifier circuit 300 and a fourth-stage operational amplifier circuit 400, and specifically comprises the following steps:
as shown in fig. 2, a circuit configuration diagram of the first-stage operational amplifier circuit 100 and the second-stage operational amplifier circuit 200 is shown, wherein fig. 2 is cut out from fig. 1, and only serves to further explain internal components of the first-stage operational amplifier circuit 100 and the second-stage operational amplifier circuit 200.
In the first-stage operational amplifier circuit 100, a forward input terminal 101 of the first-stage operational amplifier circuit 100 is connected to a dc voltage, and a reverse input terminal 102 is connected to a current-type sensor. The first capacitor 104 is connected across the inverting input 102 and the output 103 of the first stage operational amplifier circuit. The first resistor 105 is connected across the inverting input 102 of the first stage op amp and the second resistor 106. The second resistor 106 is connected in series with the output end 103 of the first stage operational amplifier circuit and is connected with the first capacitor 104 and the first resistor 105.
In some embodiments, the first stage operational amplifier circuit 100 is a transimpedance amplifier circuit, also referred to as a transimpedance amplifier (Trans-ImpedanceAmplifier, TIA). In this embodiment, the input of the first-stage operational amplifier circuit is a current signal output by the current sensor, and the output is a voltage signal, where a=y (voltage)/X (current) has a dimension of a resistor, so the first-stage operational amplifier circuit is a transimpedance amplifier circuit.
In some embodiments, the forward input terminal 101 of the first stage operational amplifier circuit 100 is connected to a 2.5V dc voltage, so as to control the output voltage of the entire operational amplifier circuit below 2.5V, which is convenient for the a/D converter to collect. The a/D converter refers to a converter between an analog signal and a digital signal, that is, converts the analog signal into the digital signal.
In some embodiments, the first capacitor 104 is a capacitor that maintains the gain broadband requirements of the first stage op amp circuit 100; the first resistor 105 is a resistor for maintaining the gain requirement of the first stage operational amplifier circuit 100. Specifically, it can be understood that: the first-stage operational amplifier circuit provided by the utility model can amplify a direct current signal into a direct current voltage signal with the power of 100 ten thousand times, the broadband of the circuit is 1-28 kHz, if the first capacitor 104 is not provided, the current signal can be distorted in a large probability when passing through the first operational amplifier circuit 100, namely the amplification factor of the direct current signal is not 100 ten thousand times that of the preset value, so that the first capacitor 104 plays a role in keeping the gain of the circuit stable; the first-stage operational amplifier circuit 100 is a negative feedback operational amplifier circuit, and for example, the output of the first-stage operational amplifier circuit is required to be lower than 2.5V, the maximum input current signal is 2.5uA, and according to the characteristics of the virtual short and the virtual break of the negative feedback operational amplifier circuit, the value of the negative feedback first resistor 105 can be calculated, that is, the first resistor 105 determines the range of the output signal of the first-stage operational amplifier circuit 100.
In some embodiments, the input nA-level small current signal may be amplified to a mV-level voltage signal by setting appropriate capacitance and resistance values for the first capacitor 104, the first resistor 105, and the second resistor 106 of the first stage op-amp circuit 100. The first capacitor 104 is set to 20pF, the first resistor 105 is set to 100 Ω, and the second resistor 106 is set to 1mΩ.
In the second-stage operational amplifier circuit 200, a forward input terminal 201 of the second-stage operational amplifier circuit 200 is connected to a dc voltage, and a reverse input terminal 202 is connected to the output terminal 103 of the first-stage operational amplifier circuit 100 through a second resistor 106 and a third resistor 204 connected in series. A fourth resistor 205 is connected across the inverting input 202 and the output 203 of the second stage op amp 200.
In some embodiments, the second stage operational amplifier circuit is an operational amplifier circuit that limits amplitude-frequency distortion. The amplitude-frequency distortion refers to distortion caused by different amplification factors of input signals with different frequencies by an amplifying circuit.
In some embodiments, the positive input 201 of the second stage op-amp circuit 200 is connected to a 2.5V dc voltage.
In some embodiments, the first resistor 105 is connected in series with the second capacitor 206 to be grounded, so as to filter the voltage ripple output by the first stage operational amplifier circuit 100.
In some embodiments, the third resistor 204 and the fourth resistor 205 have equal resistance values to maintain the gain of the second stage op-amp circuit 200 at 1.
As shown in fig. 3, the circuit structures of the third-stage operational amplifier circuit 300 and the fourth-stage operational amplifier circuit 400 are shown, wherein fig. 3 is cut out from fig. 1, and is only used for further explaining the internal components of the third-stage operational amplifier circuit 300 and the fourth-stage operational amplifier circuit 400.
In the third-stage operational amplifier circuit 300, a forward input terminal 301 of the third-stage operational amplifier circuit 300 is connected to the output terminal 203 of the second-stage operational amplifier circuit 200 through a fifth resistor 304 and a sixth resistor 305 connected in series, and an inverse input terminal 302 is connected to a third capacitor 306. The third capacitor 306 is connected across the sixth resistor 305 and the output 303 of the third stage 300.
The positive input terminal 301 of the third operational amplifier 300 is connected in series to the fourth capacitor 307 for grounding.
In the fourth-stage operational amplifier circuit 400, a forward input terminal 401 of the fourth-stage operational amplifier circuit 400 is connected to the output terminal 303 of the third-stage operational amplifier circuit 300 through a seventh resistor 404 and an eighth resistor 405 connected in series, and a reverse input terminal 402 is connected to a fifth capacitor 406. A fifth capacitor 406 is connected across the eighth resistor 405 and the output 403 of the fourth stage op-amp 400.
The positive input terminal 401 of the fourth operational amplifier circuit 400 is connected in series to the sixth capacitor 407 for grounding.
In some embodiments, the third stage op-amp 300 and the fourth stage op-amp 400 form a second order SK type low pass filter to reduce noise interference of the first stage op-amp 100 and the second stage op-amp 200.
In some embodiments, in the third stage 300, the resistance of the fifth resistor 304 and the sixth resistor 305 and the capacitance of the third capacitor 306 and the fourth capacitor 307 are determined by the gain bandwidth of the first stage 100.
In some embodiments, in the fourth stage operational amplifier circuit, the resistance values of the seventh resistor 404 and the eighth resistor 405, and the capacitance values of the fifth capacitor 406 and the sixth capacitor 407 are determined by the gain bandwidth of the first stage operational amplifier circuit 100.
The operational amplifier circuit of the present utility model is further described with reference to an embodiment, as shown in fig. 4: the circuit comprises a first-stage operational amplifier circuit, a second-stage operational amplifier circuit, a third-stage operational amplifier circuit and a fourth-stage operational amplifier circuit.
In the first-stage operational amplifier circuit, a forward input end is connected with 2.5V direct current voltage, and the output voltage of the whole operational amplifier circuit is controlled below 2.5V, so that the acquisition of an A/D converter is facilitated. The first capacitor is marked as C1, the capacitance value is set to be 20pF, and the first capacitor is connected across the reverse input end and the output end; the first resistor is marked as R1, the resistance value is set to be 1MΩ, and the reverse input end and the second resistor are connected in a bridging way; the second resistor is denoted as R2, has a resistance value of 100deg.C, and is connected in series with the output terminal and connected with the first capacitor C1 and the first resistor R1. The first stage operational amplifier circuit amplifies a current signal of the nA stage to a voltage signal of the mV stage.
In the second-stage operational amplifier circuit, a positive input end is connected with 2.5V direct-current voltage; the third resistor and the fourth resistor are respectively marked as R3 and R4, and the resistance values are all set to be 1MΩ so as to ensure that the amplification factor of the second-stage operational amplifier circuit is 1, namely the gain is 1. The second capacitor is marked as C2, and the capacitance value is set to be 100nF and is used for filtering voltage ripple output by the first-stage operational amplifier circuit.
In the third-stage operational amplifier circuit and the fourth-stage operational amplifier circuit, the fifth resistor, the sixth resistor, the seventh resistor and the eighth resistor are respectively marked as R5, R6, R7 and R8, and the resistance values are all set to be 1KΩ according to the gain bandwidth of the first-stage operational amplifier circuit; the third capacitor, the fourth capacitor, the fifth capacitor and the sixth capacitor are respectively denoted as C3, C4, C5 and C6, and the capacitance values are all set to be 0.1uF according to the gain bandwidth of the first-stage operational amplifier circuit. The third-stage operational amplifier circuit and the fourth-stage operational amplifier circuit form a second-order SK type low-pass filter so as to reduce noise output by the first-stage operational amplifier circuit and the second-stage operational amplifier circuit.
Based on the specific embodiment, the test result shows that the operational amplifier circuit provided by the utility model can amplify the nA-level small current signal into the mV-level voltage signal, can inhibit noise within 1nA range, and ensures that the signal finally output to the A/D converter has the characteristics of high precision, high amplification factor, low noise and low nonlinearity.
In summary, the present utility model provides a high-precision and low-noise operational amplifier circuit, which includes a first-stage operational amplifier circuit, a second-stage operational amplifier circuit, a third-stage operational amplifier circuit and a fourth-stage operational amplifier circuit; the first-stage operational amplifier circuit is used for amplifying a small current signal of the nA stage output by the current type sensor into a voltage signal of the mV stage; the second-stage operational amplifier circuit is used for limiting amplitude-frequency distortion of the amplified signal output by the first-stage operational amplifier circuit; the third-stage operational amplifier circuit and the fourth-stage operational amplifier circuit are used for filtering signals output by the second-stage operational amplifier circuit. The operational amplifier circuit provided by the utility model can amplify the output signal of the nA-level current type sensor to a signal range which can be acquired by the A/D converter, and the processed signal has the characteristics of high precision, low noise and low nonlinearity.
These are merely examples that are intended to be explicitly recited in this description, and all possible combinations of values recited between the lowest value and the highest value are believed to be explicitly stated in the description in a similar manner.
The term "consisting essentially of …" describing a combination shall include the identified element, ingredient, component or step as well as other elements, ingredients, components or steps that do not substantially affect the essential novel features of the combination. The use of the terms "comprises" or "comprising" to describe combinations of elements, components, or steps herein also contemplates embodiments consisting essentially of such elements, components, or steps. By using the term "may" herein, it is intended that any attribute described as "may" be included is optional.
Multiple elements, components, parts or steps can be provided by a single integrated element, component, part or step. Alternatively, a single integrated element, component, part or step may be divided into separate plural elements, components, parts or steps. The disclosure of "a" or "an" to describe an element, component, feature or step is not to be taken as excluding other elements, components, features or steps.
The above description is only of the preferred embodiments of the present utility model and is not intended to limit the present utility model, and various modifications and variations can be made to the embodiments of the present utility model by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model should be included in the protection scope of the present utility model.
Claims (10)
1. An operational amplifier circuit, comprising:
a first stage operational amplifier circuit; the positive input end of the first-stage operational amplifier circuit is connected with direct-current voltage, and the negative input end of the first-stage operational amplifier circuit is connected with a current type sensor; the first capacitor is connected across the reverse input end and the output end of the first-stage operational amplifier circuit; the first resistor is connected with the reverse input end of the first-stage operational amplifier circuit in a bridging way and the second resistor; the second resistor is connected in series with the output end of the first-stage operational amplifier circuit and is connected with the first capacitor and the first resistor;
a second-stage operational amplifier circuit; the positive input end of the second-stage operational amplifier circuit is connected with direct-current voltage, and the reverse input end of the second-stage operational amplifier circuit is connected with the output end of the first-stage operational amplifier circuit through a second resistor and a third resistor which are connected in series; the fourth resistor is connected across the reverse input end and the output end of the second-stage operational amplifier circuit;
a third-stage operational amplifier circuit; the positive input end of the third-stage operational amplifier circuit is connected with the output end of the second-stage operational amplifier circuit through a fifth resistor and a sixth resistor which are connected in series, and the reverse input end of the third-stage operational amplifier circuit is connected with a third capacitor; the third capacitor is connected with the output ends of the sixth resistor and the third-stage operational amplifier circuit in a bridging way; the positive input end of the third-stage operational amplifier circuit is connected in series with a fourth capacitor for grounding;
a fourth-stage operational amplifier circuit; the positive input end of the fourth-stage operational amplifier circuit is connected with the output end of the third-stage operational amplifier circuit through a seventh resistor and an eighth resistor which are connected in series, and the reverse input end of the fourth-stage operational amplifier circuit is connected with a fifth capacitor; the fifth capacitor is connected with the eighth resistor and the output end of the fourth-stage operational amplifier circuit in a bridging way; and the positive input end of the fourth-stage operational amplifier circuit is connected with a sixth capacitor in series for grounding.
2. The operational amplifier circuit of claim 1, wherein the first stage operational amplifier circuit is a transimpedance amplifier circuit.
3. The operational amplifier circuit of claim 1, wherein the positive inputs of the first stage operational amplifier circuit and the second stage operational amplifier circuit are connected to a dc voltage of 2.5V.
4. The operational amplifier circuit of claim 1, wherein the second stage operational amplifier circuit is an operational amplifier circuit that limits amplitude-frequency distortion.
5. The operational amplifier circuit of claim 1, wherein in the second stage operational amplifier circuit, the first resistor is connected in series with a second capacitor to ground to filter voltage ripple output by the first stage operational amplifier circuit.
6. The operational amplifier circuit of claim 1, wherein the third resistor and the fourth resistor have equal values to maintain the second stage operational amplifier circuit gain at 1.
7. The operational amplifier circuit of claim 1, wherein the third stage operational amplifier circuit and the fourth stage operational amplifier circuit form a second order SK type low pass filter to reduce noise interference of the first stage operational amplifier circuit and the second stage operational amplifier circuit.
8. The operational amplifier circuit of claim 1, wherein in the third stage operational amplifier circuit, the resistance values of the fifth resistor, the sixth resistor, and the capacitance values of the third capacitor and the fourth capacitor are determined by gain bandwidths of the first stage operational amplifier circuit.
9. The operational amplifier circuit of claim 1, wherein in the fourth stage operational amplifier circuit, the resistance values of the seventh resistor, the eighth resistor, and the capacitance values of the fifth capacitor and the sixth capacitor are determined by a gain bandwidth of the first stage operational amplifier circuit.
10. The operational amplifier circuit of claim 1, wherein the first capacitance value is set to 20pF, the first resistance value is set to 100 Ω, and the second resistance value is set to 1mΩ, to amplify the nA-stage current signal input at the positive input of the first stage operational amplifier circuit into the mV-stage voltage signal without distortion.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202320853825.2U CN219697610U (en) | 2023-04-17 | 2023-04-17 | Operational amplifier circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202320853825.2U CN219697610U (en) | 2023-04-17 | 2023-04-17 | Operational amplifier circuit |
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| Publication Number | Publication Date |
|---|---|
| CN219697610U true CN219697610U (en) | 2023-09-15 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202320853825.2U Active CN219697610U (en) | 2023-04-17 | 2023-04-17 | Operational amplifier circuit |
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| Country | Link |
|---|---|
| CN (1) | CN219697610U (en) |
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- 2023-04-17 CN CN202320853825.2U patent/CN219697610U/en active Active
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