CN114236221B - Differential voltage measurement circuit, device and method - Google Patents
Differential voltage measurement circuit, device and method Download PDFInfo
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- CN114236221B CN114236221B CN202111193338.XA CN202111193338A CN114236221B CN 114236221 B CN114236221 B CN 114236221B CN 202111193338 A CN202111193338 A CN 202111193338A CN 114236221 B CN114236221 B CN 114236221B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/25—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques
Abstract
The application provides a differential voltage measurement circuit, a differential voltage measurement device and a differential voltage measurement method, wherein the differential voltage measurement circuit comprises a common mode error correction module and a differential voltage measurement module, wherein the common mode error correction module is used for generating a common mode error correction signal according to a first voltage signal and a second voltage signal; the differential voltage measurement module is connected with the first voltage signal, the second voltage signal and the common mode error correction module and is used for generating a target differential amplified voltage signal for eliminating common mode errors according to the first voltage signal, the second voltage signal and the common mode error correction signal. The differential voltage measurement circuit provided by the application has the advantages that the common-mode error correction module is arranged, so that the output voltage is adapted to the change of the common-mode input voltage, and finally, the common-mode error is eliminated after the common-mode error correction voltage and the differential voltage measurement voltage are summed, and an accurate differential voltage measurement signal is generated.
Description
Technical Field
The present application relates to the field of integrated circuit testing technologies, and in particular, to a differential voltage measurement circuit, a differential voltage measurement device, and a differential voltage measurement method.
Background
The differential amplifying circuit is a direct coupling amplifying circuit, and has good electrical symmetry, so that the differential amplifying circuit has strong inhibition effect on common mode signals, and can effectively amplify the signals. In order to verify the effect of signal amplification, in an instrument and meter measurement circuit, precise measurement of differential voltage is required.
The traditional analog circuit correction method needs to reconnect an original differential voltage measurement circuit, and for a circuit comprising a differential amplifier chip, as the positive and negative input ends of an operational amplifier are arranged inside the chip, a potentiometer cannot be added to eliminate common mode errors through the traditional analog circuit correction method, on the other hand, when high-voltage differential voltage is measured or has high-voltage common mode voltage, the working voltages at two ends of a variable potentiometer are higher, a digital potentiometer cannot be used at the moment, and only a manual potentiometer can be used, so that the debugging difficulty and the danger are increased, and the debugging efficiency is reduced.
Disclosure of Invention
Based on this, it is necessary to provide a differential voltage measurement circuit, a differential voltage measurement device and a differential voltage measurement method, which can realize common mode error correction in a circuit including a differential amplifier chip and when a high-voltage differential voltage is measured or a high-voltage common mode voltage exists in the differential voltage measurement technology, thereby reducing debugging difficulty and danger and improving debugging efficiency.
One aspect of the present application provides a differential voltage measurement circuit comprising: the common mode error correction module is used for generating a common mode error correction signal according to the first voltage signal and the second voltage signal; the differential voltage measurement module is connected with the first voltage signal, the second voltage signal and the common mode error correction module and is used for generating a target differential amplified voltage signal for eliminating common mode errors according to the first voltage signal, the second voltage signal and the common mode error correction signal.
In a differential voltage measurement circuit, high requirements are placed on the accuracy of the measured voltage. In the differential voltage measurement circuit in the embodiment of the application, the high requirement of the measurement precision of the differential voltage measurement circuit can be maintained, the output voltage of the correction voltage output module is flexibly adjusted by arranging the common-mode error correction module, so that the correction voltage output module is suitable for the change of the common-mode input voltage, and finally, after the common-mode error correction voltage and the differential voltage measurement voltage are overlapped, the common-mode error can be eliminated, and an accurate differential voltage measurement signal is generated.
In one embodiment, the common mode error correction module includes a first operational amplifier, a first resistance unit, a second resistance unit, and a third resistance unit;
the first resistance unit is configured to: the first end is connected with the first voltage signal, and the second end is grounded through the third resistor unit;
the second resistance unit is configured to: the first end is connected with the second voltage signal, and the second end is grounded through the third resistor unit;
the first operational amplifier is configured to: the first input end is connected with the second end of the first resistance unit, the second end of the second resistance unit and the first end of the third resistance unit, the second input end is grounded, and the output end outputs the common mode error correction signal;
the resistance value of the first resistance unit is equal to that of the second resistance unit.
In one embodiment, the common mode error correction signal includes a first common mode error correction signal and a second common mode error correction signal that are in anti-phase with each other, wherein the first common mode error correction signal is in phase with a common mode error of the differential voltage measurement module;
the common mode error correction module is further configured to:
outputting the first common mode error correction signal when the first input end of the first operational amplifier is a forward input end and the second input end of the first operational amplifier is a reverse input end;
and outputting the second common mode error correction signal when the first input end of the first operational amplifier is an inverted input end and the second input end of the first operational amplifier is a forward input end.
In one embodiment, the common mode error correction module further comprises a selection switch, wherein the selection switch comprises a first knife, a second knife, a first terminal, a second terminal, a third terminal and a fourth terminal which are sequentially arranged;
the first terminal and the fourth terminal are connected with the second end of the first resistance unit, the second end of the second resistance unit and the first end of the third resistance unit;
the second terminal and the third terminal are grounded;
the first knife is connected with the positive input end of the first operational amplifier;
the second knife is connected with the reverse input end of the first operational amplifier;
wherein the common mode error correction module is further configured to:
outputting the first common mode error correction signal with the first blade in contact with the first terminal and the second blade in contact with the third terminal;
the second common mode error correction signal is output when the first blade is in contact connection with the second terminal and the second blade is in contact connection with the fourth terminal.
In one embodiment, the common mode error correction module further includes a fourth resistor unit and a fifth resistor unit with equal resistance values; the third resistor unit comprises an adjustable potentiometer and/or a digital potentiometer;
the fourth resistance unit is configured to: the first end is connected with the second end of the first resistor unit, the second end of the second resistor unit and the first end of the third resistor unit, and the second end is connected with the first input end of the first operational amplifier;
the fifth resistance unit is configured to: the first end is connected with the second end of the fourth resistor unit and the first input end of the first operational amplifier, and the second end is connected with the output end of the first operational amplifier;
the sliding end of the third resistor unit is connected with the second input end of the first operational amplifier;
and the common mode error correction module outputs the first common mode error correction signal or the second common mode error correction signal by adjusting the middle point position of the sliding end away from the adjustable potentiometer or the digital potentiometer.
In one embodiment, the third resistor unit comprises an adjustable potentiometer and/or a digital potentiometer;
and the amplitude of the common mode error correction signal is matched with the amplitude of the common mode error of the differential voltage measurement module by adjusting the adjustable potentiometer and/or the digital potentiometer.
In one embodiment, the differential voltage measurement module is configured to: the output reference end is connected with the output end of the common mode error correction module.
In one embodiment, the system further comprises a summing module;
the summing module is configured to: the first input end is connected with the output end of the differential voltage measurement module, the second input end is connected with the output end of the common mode error correction module, and the output end outputs the target differential amplified voltage signal.
The application also provides a differential voltage measurement device, comprising: the circuit of any preceding embodiment.
The differential voltage measuring device can be used for compensating the situation that the positive and negative input ends of the operational amplifier in the integrated differential amplifier chip are in the chip by adding the potentiometer in the traditional analog circuit correction method so as not to eliminate the generated common mode error, and can also reduce debugging difficulty and danger and improve debugging efficiency when the high-voltage differential voltage or the differential voltage is measured to have high-voltage common mode voltage.
In another aspect, the present application provides a differential voltage measurement method, implemented based on the differential voltage measurement circuit described in any one of the embodiments of the present application, where the method includes:
controlling a common mode error correction module to generate a common mode error correction signal according to the first voltage signal and the second voltage signal;
and controlling a differential voltage measurement module to generate a target differential amplified voltage signal for eliminating common mode errors according to the first voltage signal, the second voltage signal and the common mode error correction signal.
The method is realized based on the differential voltage measurement circuit in any one of the embodiments of the present application, specifically, the common-mode error correction module is controlled to generate a common-mode error correction signal according to the first voltage signal and the second voltage signal, and the differential voltage measurement module is controlled to generate a target differential amplified voltage signal for eliminating a common-mode error according to the first voltage signal, the second voltage signal and the common-mode error correction signal.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for the description of the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a conventional differential voltage measurement circuit;
FIG. 2 is a schematic diagram of a conventional differential voltage measurement circuit with analog circuit for correcting common mode errors;
FIG. 3 is a schematic diagram of a differential voltage measurement circuit according to an embodiment of the present application;
FIG. 4 is a schematic diagram of a differential voltage measurement circuit according to another embodiment of the present application;
FIG. 5 is a schematic diagram of a common mode error correction module according to an embodiment of the present application;
FIG. 6 is a schematic diagram of a common mode error correction module according to a second embodiment of the present application;
FIG. 7 is a schematic diagram of a common mode error correction module according to a third embodiment of the present application;
FIG. 8 is a schematic diagram of a common mode error correction module according to a fourth embodiment of the present application;
fig. 9 is a flow chart of a differential voltage measurement method according to an embodiment of the application.
Detailed Description
In order that the application may be readily understood, a more complete description of the application will be rendered by reference to the appended drawings. Embodiments of the application are illustrated in the accompanying drawings. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.
It will be understood that the terms first, second, etc. as used herein may be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another element. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of the present application. Both the first element and the second element are elements, but they are not the same element.
It is to be understood that in the following embodiments, "electrically connected" is understood to mean "electrically connected", "electrically connected in communication", etc., if the electrically connected circuits, modules, units, etc., have electrical signals or data transferred therebetween.
As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," and/or the like, specify the presence of stated features, integers, steps, operations, elements, components, or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or groups thereof. Also, the term "and/or" as used in this specification includes any and all combinations of the associated listed items.
Various intelligent devices are popular in the world, and the intelligent degree of the intelligent devices is not separated from sensors with different functions, and because the electric signals collected by the sensors are generally weak and not periodic, an amplifying circuit is needed to amplify the signals at first when the signals are processed.
In real life work, the application of the amplifying circuit is very wide, because the actual signal is very weak, and the amplifying circuit must be amplified to observe or drive the subsequent equipment. Whether it be a simple loudspeaker, a radio, or a complex, sophisticated variety of electronic devices, often incorporate basic functional circuitry, an amplifying circuit. The amplifying circuit is one of the most widely used electronic circuits, and is also a basic unit circuit constituting other electronic circuits. The amplifying circuit has the function of enhancing weak electric signals to required values by utilizing the current control function of the BJT or the voltage control function of the FET, and is convenient for people to measure and use. The amplifying circuit can amplify the input weak signal (simply referred to as signal, meaning changing voltage, current, etc.) to the signal with the required amplitude value and consistent with the change rule of the original input signal, namely, the signal is amplified without distortion.
The differential amplifying circuit has good noise resistance, can greatly reduce signal distortion and has good output characteristics. Many integrated circuits have differential amplifier circuits as input stages. The differential amplifying circuit takes the difference value of two input ends as a signal, mainly improves the signal precision, removes common error interference, and eliminates certain error. However, since the actual differential circuit is different from the ideal differential circuit, in the actual differential circuit, a common mode signal is generated to generate a common mode error, and in order to eliminate the common mode error, the conventional analog circuit correction method is implemented by adding a variable potentiometer to the circuit, and mainly eliminates the common mode error by controlling the ratio between resistors in the circuit to satisfy the characteristics of the ideal differential circuit.
As shown in FIG. 1, the resistance in an ideal differential voltage measurement circuit satisfies r 3 /r 1 ＝r 4 /r 2 At this time, the output voltage vo= (V 1 -V 2 )×r 3 /r 1 . In practice, it is difficult to meet the requirements of an ideal circuit because the resistance has errors which are difficult to meet r 3 /r 1 ＝r 4 / 2 And the circuit is in a common mode voltage condition, thereby making the actual differential voltage measurement circuit output voltage be:
V o ＝K dm ×V dm +K cm ×V cm ；
wherein V is dm ＝V 1 -V 2 ，V dm For the differential mode input voltage, V cm ＝(V 1 +V 2 )/2，V cm For common mode input voltage, K dm As a differential mode scaling factor, K cm Is a common mode scaling factor, K dm And K cm Dependent on the resistance r 1 Resistance r 2 Resistance r 3 Resistor r 4 The common mode scaling factor may lead to common mode errors in the differential voltage measurement.
For common mode errors generated in the differential voltage measurement, at V o Under the condition that the digital quantity is output through the analog-to-digital converter, a digital correction method can be used for reducing common mode errors; at V o In the case of directly outputting analog quantity, an analog circuit correction method is required to reduce common mode errors.
A conventional analog circuit correction method is shown in FIG. 2, where the resistor r 2 And resistance r 4 Adding a variable potentiometer r 24 Make the potentiometer r changeable 24 And a resistor r 2 Is the second one of (2)Input end is connected with a variable potentiometer r 24 A second input terminal of (a) and a resistor r 4 Is connected with the second input end of the variable potentiometer r 24 A sliding potentiometer r is connected with the second input end of the operational amplifier 24 Middle resistor r 2 The resistance value from the direction side to the sliding contact part of the potentiometer is r 24 ' sliding potentiometer r 24 Middle resistor r 4 The resistance value from the direction side to the sliding contact part of the potentiometer is r 24 ", let r 3 /r 1 ＝(r 4 +r 24 ″)/(r 2 +r 24 ') to eliminate common mode errors.
Because two input ends of the variable potentiometer added by the traditional analog circuit correction method are connected with the resistor in the original circuit, and the sliding end of the variable potentiometer is connected with the second input end of the operational amplifier, the original differential voltage measurement circuit needs to be reconnected, so that the method cannot be suitable for the situation that the positive and negative input ends of the operational amplifier in the integrated differential amplifier chip are inside the chip; meanwhile, when the high-voltage differential voltage is measured or the high-voltage common-mode voltage exists in the differential voltage, the working voltage applied to the variable potentiometer is higher, the digital potentiometer cannot be used at the moment, and only the hand-adjustable potentiometer can be used, so that the debugging difficulty and the danger can be increased intangibly, and the debugging efficiency is reduced.
Aiming at the problems that the traditional solution cannot effectively eliminate common-mode errors, based on the problems that the traditional analog circuit correction method has, the application provides a differential voltage measurement circuit which can be applied to the situation that the positive and negative input ends of an operational amplifier in an integrated differential amplifier chip are in the chip on the basis of effectively eliminating common-mode error signals and can also be applied to the measurement of high-voltage differential voltage or the situation that the differential voltage has high-voltage common-mode voltage, so that the output flexibility and diversity of the common-mode voltage correction module are increased, the debugging difficulty and the risk are reduced, and the debugging efficiency is improved.
In order to explain the technical scheme of the differential voltage measurement circuit in the application, the following description is made by specific embodiments.
In which it is arrangedIn one embodiment, as shown in fig. 3, a differential voltage measurement circuit is provided, which includes a differential voltage measurement module 100 and a common mode error correction module 200, wherein the common mode error correction module 200 is configured to perform a voltage measurement according to a first voltage signal V 1 Second voltage signal V 2 Generating a common mode error correction signal; differential voltage measurement module 100 and the first voltage signal V 1 Said second voltage signal V 2 And the common mode error correction modules 200 are connected to each other for correcting the first voltage signal V 1 Second voltage signal V 2 And the common mode error correction signal generates a target differential amplified voltage signal that cancels the common mode error.
Specifically, the output terminal of the common mode error correction module 200 is connected to the voltage reference terminal V of the differential voltage measurement module 100 ref After the common-mode error correction signal is passed through the differential voltage measurement module 100 as an input signal, a target differential amplified voltage signal for eliminating the common-mode error can be obtained at the output terminal of the differential voltage measurement module 100.
In this embodiment, the common mode error correction module 200 is electrically connected with the differential voltage measurement module 100, so that the differential voltage measurement circuit in the application can be effectively applied to the situation that the positive and negative input ends of the operational amplifier in the integrated differential amplifier chip are in the chip, and the defect that the potentiometer is added in the traditional analog correction method is overcome; on the other hand, the differential voltage measurement circuit can be applied to measurement of high-voltage differential voltage or under the condition that the differential voltage has high-voltage common-mode voltage. The differential voltage measurement circuit in the embodiment utilizes the superposition of the common-mode error correction voltage signal and the differential voltage measurement voltage signal to achieve the purposes of eliminating the common-mode error and generating the accurate differential voltage measurement signal, thereby reducing the debugging difficulty and the risk and improving the debugging efficiency.
In one embodiment, as shown in fig. 4, compared with fig. 3, the device further includes a summing module 300, where the summing module 300 is connected to both the common mode error correction module 200 and the differential voltage measurement module 100, and is configured to generate a target differential amplified voltage signal for eliminating the common mode error according to the common mode error correction signal and the differential voltage signal.
Specifically, by setting the output voltage V of the common mode error correction module 200 o2 ＝K cm ′×V cm Analog output voltage V from differential voltage measurement module 100 o1 The corrected output voltage is obtained by summing module 300:
V o ＝K dm ×V dm +K cm ×V cm +K cm ′×V cm
so that K is cm ′≈-K cm V is then o ≈K dm ×V dm The corrected output voltage V can be obtained by the common mode error correction module 200 o 。
In one embodiment, as shown in FIG. 5, the present application provides a common mode error correction module 200, which comprises a first operational amplifier OP1, a first resistor unit R 1 A second resistor unit R 2 Third resistor unit R 3 Wherein the first resistor unit R 1 Is configured to: a first end and the first voltage signal V 1 Connected with the second end via a third resistor unit R 3 Grounding; second resistor unit R 2 Is configured to: first and second voltage signals V 2 Connected with the second end via a third resistor unit R 3 Grounding; the first operational amplifier OP1 is configured to: a first input terminal and a first resistor unit R 1 Second end of (a), second resistance unit R 2 Second terminal of (a) and third resistor unit R 3 The first end of the first common mode error correction signal V is connected with the second input end of the second common mode error correction signal V o21 。
Specifically, the scaling ratio of the first operational amplifier is K amp And R is 1 ＝R 2 =r, at which time the common mode error correction module 200 outputs a voltage of:
V o21 ＝V cm ×K amp ×2×R 3 /(2×R 3 +R)
control K cm ′＝K amp ×2×R 3 /(2×R 3 +R), K cm ′≈-K cm Thereby V is provided with o21 And the common mode error is mutually offset,achieve the goal of eliminating common mode errors, V in this embodiment o21 And V is equal to cm In phase.
Further, from V o21 As can be seen from the formula of (c), in this embodiment, K cm ' is a fixed value, only a fixed size V can be produced cm To accommodate K in the differential voltage measurement module 100 cm Variation of (3), third resistance R 3 Using adjustable devices, e.g. adjustable potentiometers or digital potentiometers, a variable K can be produced cm ' the adaptability of the common mode error correction module 200 is enhanced.
Further, the first operational amplifier OP1 uses an adjustable gain amplifier, which can be adjusted by changing the amplifier scaling K amp Producing variable K cm ' the adaptability of the common mode error correction module 200 is enhanced.
In one embodiment, as shown in fig. 6, compared with the embodiment shown in fig. 5, the first input terminal and the second input terminal of the first operational amplifier OP1 are inverted in this embodiment, and the second common mode error correction signal V is obtained o22 And a second common mode error correction signal V o22 And V is equal to cm And (3) inverting.
In one embodiment, as shown in fig. 7, a common mode error correction module 200 is provided, and compared with the embodiment shown in fig. 5, the common mode error correction module 200 further includes a selection switch K, where the selection switch K includes a first blade, a second blade, and a first terminal 1, a second terminal 2, a third terminal 3, and a fourth terminal 4 that are sequentially arranged; wherein the first terminal 1, the fourth terminal 4 and the first resistor unit R 1 Second end of (a), second resistance unit R 2 Second terminal of (a) and third resistor unit R 3 Is connected with the first end of the first connecting piece; the second terminal 2 and the third terminal 3 are grounded; the first knife is connected with the positive input end of the first operational amplifier OP 1; the second knife is connected with the reverse input end of the first operational amplifier OP 1; the common mode error correction module 200 is further configured to: outputting a first common mode error correction signal V when the first blade is in contact connection with the first terminal and the second blade is in contact connection with the third terminal o21 The method comprises the steps of carrying out a first treatment on the surface of the In contact connection with the first blade and the second terminal, the second blade is connected with the first bladeIn the case of four-terminal contact connection, the second common mode error correction signal V is output o22 。
In the present embodiment, the third resistance unit R 3 Changing the third resistance unit R using an adjustable potentiometer or a digital potentiometer 3 Resistance value of (2) to produce a change K cm '. When the differential voltage measurement module 100 is K cm When changing, the third resistance unit R is adjusted 3 To adjust K cm ' make K cm ′≈-K cm So that the output voltage V of the common mode error correction module 200 o2 And the common mode error is counteracted, so that the purpose of eliminating the common mode error is achieved.
In one embodiment, as shown in fig. 8, a common mode error correction module 200 is provided, and compared with fig. 6, the common mode error correction module further includes a fourth resistor unit R with equal resistance values 4 Fifth resistor unit R 5 The method comprises the steps of carrying out a first treatment on the surface of the Wherein the fourth resistor unit R 4 Is configured to: first end and first resistor unit R 1 Second end of (a), second resistance unit R 2 Second terminal of (a) and third resistor unit R 3 The first end of the first operational amplifier OP1 is connected with the second end of the first operational amplifier OP 1; fifth resistor unit R 5 Is configured to: first end and fourth resistor unit R 4 The second end of the first operational amplifier OP1 is connected with the first input end of the first operational amplifier OP 1; third resistor unit R 3 Is connected with the second input end of the first operational amplifier OP 1; by adjusting the third resistance unit R 3 The sliding end of the adjustable potentiometer or the digital potentiometer is far away from the middle point position of the adjustable potentiometer or the digital potentiometer, so that the common mode error correction module outputs a first common mode error correction signal V o21 Or a second common mode error correction signal V o22 。
Specifically, in the present embodiment, in order to reduce the error, the fourth resistance unit R 4 And a fifth resistor unit R 5 The sum of the resistance values of (a) is far greater than that of the third resistance unit R 3 Resistance value of (2); taking a third resistor unit R 3 The resistance from the sliding end to the far ground end is R 3 ' the resistance between the sliding end and the ground potential is R 3 "due to R 4 +R 5 Far greater than R 3 Flow through R can be ignored 4 +R 5 Influence of current, at this time:
when 2X R 3 ″<R 3 I.e. third resistor unit R 3 K when the sliding end of the potentiometer is positioned between the midpoint of the potentiometer and the ground potential cm ' is negative, V o2 Output of (V) and V cm Inverting;
when 2X R 3 ″>R 3 I.e. third resistor unit R 3 K is between the midpoint of the potentiometer and the far ground cm ' positive, V o2 Output of (V) and V cm In phase.
By sliding the third resistance unit R 3 Can flexibly adjust the output voltage V of the common mode error correction module 200 o2 So as to adapt to the change of common mode errors and improve the debugging efficiency.
In one embodiment, a differential voltage measurement device is provided that includes any of the circuits described in the embodiments of the present application.
The differential voltage measuring device can be used for compensating the common mode error which is generated by adding the potentiometer in the traditional analog circuit correction method under the condition that the positive and negative input ends of the operational amplifier in the differential amplifier chip are inside the chip by controlling the common mode error correction module to generate the common mode error correction signal according to the first voltage signal and the second voltage signal and simultaneously enabling the differential voltage measuring module to generate the target differential amplified voltage signal for eliminating the common mode error according to the first voltage signal, the second voltage signal and the common mode error correction signal.
In one embodiment, a differential voltage measurement method is provided, which is implemented based on the differential voltage measurement circuit described in any one embodiment of the present application, and the method includes:
step S22: controlling a common mode error correction module to generate a common mode error correction signal according to the first voltage signal and the second voltage signal;
step S24: and controlling a differential voltage measurement module to generate a target differential amplified voltage signal for eliminating common mode errors according to the first voltage signal, the second voltage signal and the common mode error correction signal.
The method is realized based on the differential voltage measurement circuit in any one of the embodiments of the present application, specifically, the common-mode error correction module is controlled to generate a common-mode error correction signal according to the first voltage signal and the second voltage signal, and the differential voltage measurement module is controlled to generate a target differential amplified voltage signal for eliminating the common-mode error according to the first voltage signal, the second voltage signal and the common-mode error correction signal.
It should be noted that, in the embodiments provided in the present application, it should be understood that the disclosed technical content may be implemented in other manners. The system embodiments described above are merely exemplary, and for example, the division of the units may be a logic function division, and there may be another division manner when actually implemented, for example, a plurality of units or components may be combined or may be integrated into another system, or some features may be omitted or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed with each other may be through some interfaces, units or modules, or may be in electrical or other forms.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.
In addition, each functional unit in the embodiments of the present application may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit. The integrated units described above may be implemented in hardware.
Finally, it is noted that the above embodiments are only for illustrating the technical solution of the present application and not for limiting the same, and although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications and equivalents may be made thereto without departing from the spirit and scope of the present application, which is intended to be covered by the claims of the present application.
Claims (10)
1. A differential voltage measurement circuit, comprising:
the common mode error correction module is used for generating a common mode error correction signal according to the first voltage signal and the second voltage signal;
the differential voltage measurement module is connected with the first voltage signal, the second voltage signal and the common mode error correction module and is used for generating a target differential amplified voltage signal for eliminating common mode errors according to the first voltage signal, the second voltage signal and the common mode error correction signal;
the common mode error correction module comprises a first operational amplifier, a first resistor unit, a second resistor unit and a third resistor unit;
the first resistance unit is configured to: the first end is connected with the first voltage signal, and the second end is grounded through the third resistor unit;
the second resistance unit is configured to: the first end is connected with the second voltage signal, and the second end is grounded through the third resistor unit;
the first operational amplifier is configured to: the first input end is connected with the second end of the first resistance unit, the second end of the second resistance unit and the first end of the third resistance unit, the second input end is grounded, and the output end outputs the common mode error correction signal;
the resistance value of the first resistance unit is equal to that of the second resistance unit.
2. The circuit of claim 1, wherein the common mode error correction signal comprises a first common mode error correction signal and a second common mode error correction signal that are anti-phase to each other, wherein the first common mode error correction signal is in phase with a common mode error of the differential voltage measurement module;
the common mode error correction module is further configured to:
outputting the first common mode error correction signal when the first input end of the first operational amplifier is a forward input end and the second input end of the first operational amplifier is a reverse input end;
and outputting the second common mode error correction signal when the first input end of the first operational amplifier is an inverted input end and the second input end of the first operational amplifier is a forward input end.
3. The circuit of claim 2, wherein the common mode error correction module further comprises a selection switch comprising a first blade, a second blade, and first, second, third, and fourth terminals arranged in sequence;
the first terminal and the fourth terminal are connected with the second end of the first resistance unit, the second end of the second resistance unit and the first end of the third resistance unit;
the second terminal and the third terminal are grounded;
the first knife is connected with the positive input end of the first operational amplifier;
the second knife is connected with the reverse input end of the first operational amplifier;
wherein the common mode error correction module is further configured to:
outputting the first common mode error correction signal with the first blade in contact with the first terminal and the second blade in contact with the third terminal;
the second common mode error correction signal is output when the first blade is in contact connection with the second terminal and the second blade is in contact connection with the fourth terminal.
4. The circuit of claim 2, wherein the common mode error correction module further comprises a fourth resistor unit and a fifth resistor unit having equal resistance values; the third resistor unit comprises an adjustable potentiometer and/or a digital potentiometer;
the fourth resistance unit is configured to: the first end is connected with the second end of the first resistor unit, the second end of the second resistor unit and the first end of the third resistor unit, and the second end is connected with the first input end of the first operational amplifier;
the fifth resistance unit is configured to: the first end is connected with the second end of the fourth resistor unit and the first input end of the first operational amplifier, and the second end is connected with the output end of the first operational amplifier;
the sliding end of the third resistor unit is connected with the second input end of the first operational amplifier;
and the common mode error correction module outputs the first common mode error correction signal or the second common mode error correction signal by adjusting the middle point position of the sliding end away from the adjustable potentiometer or the digital potentiometer.
5. The circuit according to any of claims 2-4, wherein the third resistive element comprises an adjustable potentiometer and/or a digital potentiometer;
and the amplitude of the common mode error correction signal is matched with the amplitude of the common mode error of the differential voltage measurement module by adjusting the adjustable potentiometer and/or the digital potentiometer.
6. The circuit of claim 1, wherein the first operational amplifier is an adjustable gain amplifier.
7. The circuit of any of claims 1-4, wherein the differential voltage measurement module is configured to: the output reference end is connected with the output end of the common mode error correction module.
8. The circuit of any one of claims 1-4, further comprising a summing module;
the summing module is configured to: the first input end is connected with the output end of the differential voltage measurement module, the second input end is connected with the output end of the common mode error correction module, and the output end outputs the target differential amplified voltage signal.
9. A differential voltage measurement device, comprising:
the circuit of any one of claims 1-8.
10. A differential voltage measurement method, comprising:
controlling a common mode error correction module to generate a common mode error correction signal according to the first voltage signal and the second voltage signal;
controlling a differential voltage measurement module to generate a target differential amplified voltage signal for eliminating common mode errors according to the first voltage signal, the second voltage signal and the common mode error correction signal;
the common mode error correction module comprises a first operational amplifier, a first resistor unit, a second resistor unit and a third resistor unit;
the first resistance unit is configured to: the first end is connected with the first voltage signal, and the second end is grounded through the third resistor unit;
the second resistance unit is configured to: the first end is connected with the second voltage signal, and the second end is grounded through the third resistor unit;
the first operational amplifier is configured to: the first input end is connected with the second end of the first resistance unit, the second end of the second resistance unit and the first end of the third resistance unit, the second input end is grounded, and the output end outputs the common mode error correction signal;
the resistance value of the first resistance unit is equal to that of the second resistance unit.
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