CN113054933A - Voltage differential sampling circuit based on variable differential and matched resistor - Google Patents
Voltage differential sampling circuit based on variable differential and matched resistor Download PDFInfo
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- CN113054933A CN113054933A CN202110283413.5A CN202110283413A CN113054933A CN 113054933 A CN113054933 A CN 113054933A CN 202110283413 A CN202110283413 A CN 202110283413A CN 113054933 A CN113054933 A CN 113054933A
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
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- H03F3/45—Differential amplifiers
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Abstract
The invention discloses a voltage differential sampling circuit, wherein in the voltage differential sampling circuit, an operational amplifier is provided with a positive end and a negative end which are connected with a collected voltage Uin and an output end which is connected with an output voltage Uout; the first variable differential sampling resistor is arranged between the acquisition voltage Uin and the negative terminal; the second variable differential sampling resistor is arranged between the acquisition voltage Uin and the positive terminal, the first variable differential sampling resistor and/or the second variable differential sampling resistor comprise n fixed resistors and n controllable switches connected in parallel at two ends of the fixed resistors, and the controller is connected with the controllable switches to control the on-off; one end of the first matching resistor is connected between the first variable differential sampling resistor and the negative end, and the other end of the first matching resistor is connected between the output end and the output voltage Uout; one end of the second matching resistor is connected between the second variable differential sampling resistor and the positive end, and the other end of the second matching resistor is grounded.
Description
Technical Field
The invention relates to the technical field of power electronics, in particular to a voltage differential sampling circuit based on variable differential and matched resistors.
Background
The differential sampling circuit adopting the operational amplifier is widely applied to occasions needing voltage sampling, such as electronics, power electronics and the like, due to the advantages of simple structure, low cost, high sampling precision and the like. The differential sampling circuit utilizes the high gain multiplying power of the operational amplifier, and voltage signals needing to be sampled are added to the positive signal input end and the negative signal input end of the operational amplifier through resistors, so that sampling errors caused by device deviation, device parameter temperature drift and the like are offset, and the precision of the sampling circuit is improved.
The traditional differential sampling circuit has great advantages in corresponding to the sampling of fixed voltage, but has the disadvantage of large sampling range on occasions needing to sample voltage, when the sampling voltage of the differential sampling circuit with fixed sampling ratio is higher than the set voltage, the input current of the sampling circuit is increased, and the over-power damage of the sampling resistor can be caused because the power of the sampling resistor is designed according to the set sampling voltage; the upper line of the designed value of the output voltage amplitude of the differential sampling circuit corresponding to the rated acquisition voltage is generally the positive and negative power supply voltage of the operational amplifier, when the acquisition voltage is overhigh, the corresponding output voltage value can exceed the positive and negative voltage amplitude of the power supply, and at the moment, nonlinear distortion can occur in the output voltage; when the sampling voltage of the differential sampling circuit with the fixed sampling ratio is lower than the set voltage, the input current of the sampling circuit is reduced, and the input current is smaller than the minimum designed working current of the sampling circuit, so that the sampling error is larger, and the sampling precision requirement cannot be met.
The above information disclosed in this background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is well known to those of ordinary skill in the art.
Disclosure of Invention
The invention aims to provide a voltage differential sampling circuit, which is used for improving the voltage collecting range of the differential sampling circuit, improving the sampling precision of the differential sampling circuit and reducing the hardware implementation cost.
In order to achieve the above purpose, the invention provides the following technical scheme:
the invention relates to a voltage differential sampling circuit based on variable differential and matched resistors, which is characterized in that,
the voltage differential sampling circuit comprises a controller, at least 2 variable differential sampling resistors and at least 2 matching resistors connected to each variable differential sampling resistor;
the voltage differential sampling circuit adjusts the resistance values of the 2 differential sampling resistors through a controller to adjust the range of the collected voltage;
wherein,
at least 1 variable differential sampling resistor is arranged between the acquisition voltage Uin and the negative terminal;
at least 1 variable differential sampling resistor is arranged between the acquisition voltage Uin and the positive terminal;
at least 1 matching resistor is respectively connected between the 1 variable differential sampling resistor and the output voltage Uout of the sampling circuit;
at least 1 matching resistor is respectively connected between the 1 variable differential sampling resistor and the grounding end of the sampling circuit.
The voltage differential sampling circuit comprises:
an operational amplifier having a positive terminal and a negative terminal connected to the acquisition voltage Uin and an output terminal connected to the output voltage Uout;
the first variable differential sampling resistor is arranged between the acquisition voltage Uin and the negative terminal;
the first variable differential sampling resistor and/or the second variable differential sampling resistor comprise n fixed resistors and n controllable switches connected in parallel at two ends of the fixed resistors, and n is a natural number;
the controller is connected with the controllable switch to control the opening and closing;
one end of the first matching resistor is connected between the first variable differential sampling resistor and the negative end, and the other end of the first matching resistor is connected between the output end and the output voltage Uout;
and one end of the second matching resistor is connected between the second variable differential sampling resistor and the positive end, and the other end of the second matching resistor is grounded.
In the voltage differential sampling circuit, the operational amplifier is grounded.
In the voltage differential sampling circuit, a first variable differential sampling resistor and a second variable differential sampling resistor in at least 2 variable differential sampling resistors are the same.
In the voltage differential sampling circuit, the first matching resistor and the second matching resistor in at least 2 matching resistors are the same.
In the voltage differential sampling circuit, the controllable switch is a passive switch and/or an active switch.
In the voltage differential sampling circuit, the passive switch comprises a relay, and the active switch comprises a transistor or a mos tube.
In the above technical solution, the voltage differential sampling circuit provided by the present invention has the following beneficial effects: the voltage differential sampling circuit is simple in structure and convenient to use, the range of the collected voltage is adjusted by adjusting the resistance value of the differential sampling resistor through the controller, and then wide-range and high-precision voltage sampling is realized.
Drawings
In order to more clearly illustrate the embodiments of the present application or technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments described in the present invention, and other drawings can be obtained by those skilled in the art according to the drawings.
FIG. 1 is a schematic diagram of a voltage differential sampling circuit;
fig. 2 is a schematic diagram of a first variable differential sampling resistor of the voltage differential sampling circuit.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be described in detail and completely with reference to fig. 1 to 2 of the drawings of the embodiments of the present invention, and it is apparent that the described embodiments are a part of the embodiments of the present invention, but not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.
Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.
In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations and positional relationships based on those shown in the drawings, and are used only for convenience of description and simplicity of description, and do not indicate or imply that the equipment or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be considered as limiting the present invention.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.
In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.
In order to make the technical solutions of the present invention better understood, those skilled in the art will now describe the present invention in further detail with reference to the accompanying drawings.
In one embodiment, a voltage differential sampling circuit based on variable differential and matched resistors,
the voltage differential sampling circuit comprises a controller, at least 2 variable differential sampling resistors and at least 2 matching resistors connected to each variable differential sampling resistor;
the voltage differential sampling circuit adjusts the resistance values of the 2 differential sampling resistors through a controller to adjust the range of the collected voltage;
wherein,
at least 1 variable differential sampling resistor is arranged between the acquisition voltage Uin and the negative terminal;
at least 1 variable differential sampling resistor is arranged between the acquisition voltage Uin and the positive terminal;
at least 1 matching resistor is respectively connected between the 1 variable differential sampling resistor and the output voltage Uout of the sampling circuit;
at least 1 matching resistor is respectively connected between the 1 variable differential sampling resistor and the grounding end of the sampling circuit.
In the above technical scheme, the voltage differential sampling circuit provided by the invention has the following beneficial effects: the voltage differential sampling circuit is simple in structure and convenient to use, the range of the collected voltage is adjusted by adjusting the resistance value of the differential sampling resistor through the controller, and then wide-range and high-precision voltage sampling is realized.
For the traditional voltage sampling circuit, the power of the sampling resistor is designed according to the set sampling voltage, so that the over-power damage of the sampling resistor can be caused; the upper line of the designed value of the output voltage amplitude of the differential sampling circuit corresponding to the rated acquisition voltage is generally the positive and negative power supply voltage of the operational amplifier, when the acquisition voltage is overhigh, the corresponding output voltage value can exceed the positive and negative voltage amplitude of the power supply, and at the moment, nonlinear distortion can occur in the output voltage; when the sampling voltage of the differential sampling circuit with the fixed sampling ratio is lower than the set voltage, the input current of the sampling circuit is reduced, and the input current is smaller than the minimum designed working current of the sampling circuit, so that the sampling error is larger, and the sampling precision requirement cannot be met.
Referring to fig. 1, in one embodiment, a voltage differential sampling circuit of the present invention includes,
an operational amplifier having a positive terminal and a negative terminal connected to the acquisition voltage Uin and an output terminal connected to the output voltage Uout;
the first variable differential sampling resistor is arranged between the acquisition voltage Uin and the negative terminal;
the first variable differential sampling resistor and/or the second variable differential sampling resistor comprise n fixed resistors and n controllable switches connected in parallel at two ends of the fixed resistors, and n is a natural number;
the controller is connected with the controllable switch to control the opening and closing;
one end of the first matching resistor is connected between the first variable differential sampling resistor and the negative end, and the other end of the first matching resistor is connected between the output end and the output voltage Uout;
and one end of the second matching resistor is connected between the second variable differential sampling resistor and the positive end, and the other end of the second matching resistor is grounded.
In a preferred embodiment of the voltage differential sampling circuit, the operational amplifier is grounded.
In a preferred embodiment of the voltage differential sampling circuit, the first variable differential sampling resistor and the second variable differential sampling resistor are the same.
In a preferred embodiment of the voltage differential sampling circuit, the first matching resistor and the second matching resistor are the same.
In a preferred embodiment of the voltage differential sampling circuit, the controllable switches are passive switches and/or active switches.
In a preferred embodiment of the voltage differential sampling circuit, the passive switch includes a relay, and the active switch includes a transistor or a mos transistor.
The voltage differential sampling circuit comprises an operational amplifier, a first variable differential sampling resistor Rx, a second variable differential sampling resistor Rx, a matching resistor R and a variable resistor controller. The first variable differential sampling resistor Rx and the second variable differential sampling resistor Rx are respectively connected to plus and minus ports of the operational amplifier, the collection of the collected voltage Uin is realized through the matching resistor R, the collected Uin voltage and the output voltage Uout are expressed as Uout ═ Uin (Rx/R), the resistance value of the differential sampling resistor is adjustable through the variable resistor controller, and then the resistance value of the Rx is adjustable, and the collected voltage range is wide and adjustable.
In one embodiment, as shown in fig. 2, if the concept of cascade expansion is further adopted, taking the first variable differential sampling resistor as an example: the first variable differential sampling resistor is composed of R1-Rn N fixed resistors and controllable switches K1-Kn connected in parallel at two ends of the fixed resistors, N is a natural number of 1-N, the controllable switches can be composed of passive switches such as relays and the like, active switches such as transistors or mos tubes and the like, and different resistance values of the resistors are adjusted by controlling the on-state switch K through a controller.
Finally, it should be noted that: the embodiments described are only a part of the embodiments of the present application, and not all embodiments, and all other embodiments obtained by those skilled in the art without making creative efforts based on the embodiments in the present application belong to the protection scope of the present application.
While certain exemplary embodiments of the present invention have been described above by way of illustration only, it will be apparent to those of ordinary skill in the art that the described embodiments may be modified in various different ways without departing from the spirit and scope of the invention. Accordingly, the drawings and description are illustrative in nature and should not be construed as limiting the scope of the invention.
Claims (7)
1. A voltage differential sampling circuit based on variable differential and matched resistors is characterized in that,
the voltage differential sampling circuit comprises a controller, at least 2 variable differential sampling resistors and at least 2 matching resistors connected to each variable differential sampling resistor;
the voltage differential sampling circuit adjusts the resistance values of the 2 differential sampling resistors through a controller to adjust the range of the collected voltage;
wherein,
at least 1 variable differential sampling resistor is arranged between the acquisition voltage Uin and the negative terminal;
at least 1 variable differential sampling resistor is arranged between the acquisition voltage Uin and the positive terminal;
at least 1 matching resistor is respectively connected between the 1 variable differential sampling resistor and the output voltage Uout of the sampling circuit;
at least 1 matching resistor is respectively connected between the 1 variable differential sampling resistor and the grounding end of the sampling circuit.
2. A voltage differential sampling circuit according to claim 1, preferably, the voltage differential sampling circuit further comprises:
an operational amplifier having a positive terminal and a negative terminal connected to the acquisition voltage Uin and an output terminal connected to the output voltage Uout;
the first variable differential sampling resistor is arranged between the acquisition voltage Uin and the negative terminal;
the first variable differential sampling resistor and/or the second variable differential sampling resistor comprise n fixed resistors and n controllable switches connected in parallel at two ends of the fixed resistors, and n is a natural number;
the controller is connected with the controllable switch to control the opening and closing;
one end of the first matching resistor is connected between the first variable differential sampling resistor and the negative end, and the other end of the first matching resistor is connected between the output end and the output voltage Uout;
and one end of the second matching resistor is connected between the second variable differential sampling resistor and the positive end, and the other end of the second matching resistor is grounded.
3. A voltage differential sampling circuit as claimed in claim 2 wherein said operational amplifier is connected to ground.
4. The voltage differential sampling circuit of claim 1, wherein a first variable differential sampling resistor of the at least 2 variable differential sampling resistors is the same as a second variable differential sampling resistor.
5. The voltage differential sampling circuit of claim 1, wherein a first matched resistor of the at least 2 matched resistors is the same as a second matched resistor.
6. A voltage differential sampling circuit according to claim 2, wherein the controllable switches are passive switches and/or active switches.
7. The voltage differential sampling circuit of claim 6, wherein the passive switch comprises a relay and the active switch comprises a transistor or a mos transistor.
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CN102201792A (en) * | 2010-03-25 | 2011-09-28 | 上海沙丘微电子有限公司 | Automatic gain control circuit of audio power amplifier |
CN209342798U (en) * | 2018-12-12 | 2019-09-03 | 南宁职业技术学院 | A kind of voltage sampling apparatus |
CN111030624A (en) * | 2019-12-31 | 2020-04-17 | 江苏润石科技有限公司 | Common mode rejection ratio configurable instrumentation amplifier and configuration method thereof |
CN211860056U (en) * | 2019-12-31 | 2020-11-03 | 江苏中海达海洋信息技术有限公司 | Novel signal matching circuit of differential amplification circuit |
CN112491260A (en) * | 2020-11-25 | 2021-03-12 | 珠海格力电器股份有限公司 | Charging protection circuit and method and switching power supply |
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- 2021-03-16 CN CN202110283413.5A patent/CN113054933A/en active Pending
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102201792A (en) * | 2010-03-25 | 2011-09-28 | 上海沙丘微电子有限公司 | Automatic gain control circuit of audio power amplifier |
CN209342798U (en) * | 2018-12-12 | 2019-09-03 | 南宁职业技术学院 | A kind of voltage sampling apparatus |
CN111030624A (en) * | 2019-12-31 | 2020-04-17 | 江苏润石科技有限公司 | Common mode rejection ratio configurable instrumentation amplifier and configuration method thereof |
CN211860056U (en) * | 2019-12-31 | 2020-11-03 | 江苏中海达海洋信息技术有限公司 | Novel signal matching circuit of differential amplification circuit |
CN112491260A (en) * | 2020-11-25 | 2021-03-12 | 珠海格力电器股份有限公司 | Charging protection circuit and method and switching power supply |
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