CN114236221A - Differential voltage measurement circuit, device and method - Google Patents
Differential voltage measurement circuit, device and method Download PDFInfo
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- CN114236221A CN114236221A CN202111193338.XA CN202111193338A CN114236221A CN 114236221 A CN114236221 A CN 114236221A CN 202111193338 A CN202111193338 A CN 202111193338A CN 114236221 A CN114236221 A CN 114236221A
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- 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 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 amplification 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. According to the differential voltage measuring circuit, the common-mode error correction module is arranged, so that the output voltage of the differential voltage measuring circuit adapts to the change of the common-mode input voltage, and finally, after the common-mode error correction voltage and the differential voltage measuring voltage are summed, the common-mode error is eliminated, and an accurate differential voltage measuring signal is generated.
Description
Technical Field
The invention relates to the technical field of integrated circuit testing, in particular to a differential voltage measuring circuit, a differential voltage measuring device and a differential voltage measuring method.
Background
The differential amplifier circuit is a direct coupling amplifier circuit, and has good electrical symmetry, so that the differential amplifier 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 the instrumentation measurement circuit, it is necessary to perform precise measurement on the differential voltage.
The traditional analog circuit correction method needs to reconnect an original differential voltage measuring circuit, and aiming at a circuit comprising a differential amplifier chip, because the positive input end and the negative input end of an operational amplifier are arranged in the chip, a potentiometer cannot be added through the traditional analog circuit correction method to eliminate common mode errors, on the other hand, when high-voltage differential voltage or differential voltage is measured to have high-voltage common mode voltage, the working voltage at two ends of the variable potentiometer is higher, at the moment, a digital potentiometer cannot be used, only the potentiometer can be adjusted manually, so that the debugging difficulty and danger are increased, and the debugging efficiency is reduced.
Disclosure of Invention
Therefore, it is necessary to provide a differential voltage measurement circuit, a differential voltage measurement device and a differential voltage measurement method, which can implement common mode error correction in a circuit including a differential amplifier chip and when measuring a high voltage differential voltage or a high voltage common mode voltage existing in the differential voltage, compared with the conventional differential voltage measurement technology, so as to reduce the debugging difficulty and danger and improve the debugging efficiency.
One aspect of the present application provides a differential voltage measurement circuit, including: 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 amplification 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.
In a differential voltage measurement circuit, there is a high demand on the accuracy of the measured voltage. In the differential voltage measuring circuit in the embodiment of the application, the higher requirement of the measurement precision of the differential voltage measuring circuit can be maintained, the output voltage of the voltage output module is flexibly adjusted and corrected by arranging the common-mode error correction module to adapt to the change of the common-mode input voltage, and finally, after the common-mode error correction voltage and the differential voltage measuring voltage are superposed, the common-mode error can be eliminated, and an accurate differential voltage measuring signal is generated.
In one embodiment, the common mode error correction module comprises 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 resistance 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 resistance 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;
wherein a resistance value of the first resistance unit is equal to a resistance value of the second resistance unit.
In one embodiment, the common-mode error correction signal comprises a first common-mode error correction signal and a second common-mode error correction signal that are in opposite 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 terminal of the first operational amplifier is a forward input terminal and the second input terminal of the first operational amplifier is an inverting input terminal;
and outputting the second common mode error correction signal when the first input end of the first operational amplifier is a reverse 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 and a first terminal, a second terminal, a third terminal and a fourth terminal which are 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 both grounded;
the first switch is connected with a positive input end of the first operational amplifier;
the second knife is connected with the inverting 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 in a case where the first blade is in contact connection with the first terminal and the second blade is in contact connection with the third terminal;
outputting the second common mode error correction signal 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 resistance unit and a fifth resistance unit with equal resistance values; the third resistance unit comprises an adjustable potentiometer and/or a digital potentiometer;
the fourth resistance unit is configured to: the first end of the first operational amplifier is connected with the first end of the first resistance unit, the second end of the second resistance unit and the first end of the third resistance unit;
the fifth resistance unit is configured to: the first end of the first operational amplifier is connected with the second end of the fourth resistance unit and the first input end of the first operational amplifier, and the second end of the first operational amplifier is connected with the output end of the first operational amplifier;
the sliding end of the third resistance unit is connected with the second input end of the first operational amplifier;
wherein the common mode error correction module outputs the first common mode error correction signal or the second common mode error correction signal by adjusting a position of the sliding end away from a midpoint of the adjustable potentiometer or the digital potentiometer.
In one embodiment, the third resistance unit comprises an adjustable potentiometer and/or a digital potentiometer;
and adjusting the adjustable potentiometer and/or the digital potentiometer to enable the amplitude of the common-mode error correction signal to be matched with the amplitude of the common-mode error of the differential voltage measurement module.
In one embodiment, the differential voltage measurement module is configured to: and 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 amplification voltage signal.
The present application also provides a differential voltage measurement apparatus, comprising: the circuit of any of the preceding embodiments.
The differential voltage measuring device can be used for compensating the common mode error which cannot be eliminated by adding a potentiometer in the traditional analog circuit correcting method under the condition that the positive input end and the negative input end of the operational amplifier in the integrated differential amplifier chip are arranged in the chip, and simultaneously reducing the debugging difficulty and the debugging danger and improving the debugging efficiency when measuring the high-voltage differential voltage or the high-voltage common-mode voltage of the differential voltage.
In another aspect, the present application provides a differential voltage measurement method, which is implemented based on the differential voltage measurement circuit described in any of the embodiments of the present application, and 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 amplification 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.
The above method is implemented based on the differential voltage measurement circuit in any embodiment of the present application, and specifically, a common mode error correction signal can be generated by controlling the common mode error correction module according to the first voltage signal and the second voltage signal, and a target differential amplified voltage signal for eliminating a common mode error can be generated by controlling the differential voltage measurement module according to the first voltage signal, the second voltage signal and the common mode error correction signal, which can solve the problem of limitation of the conventional analog circuit correction method, and can be used in a circuit in which positive and negative input terminals of an operational amplifier in an integrated differential amplifier chip are inside the chip, to make up the problem that the conventional analog circuit correction method cannot eliminate the common mode error due to the addition of a potentiometer, and also can be used when measuring a high voltage differential voltage or a differential voltage having a high voltage common mode voltage, the debugging difficulty and the debugging danger are reduced, and the debugging efficiency is improved.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
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 circuitry to correct 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 disclosure;
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 disclosure;
fig. 9 is a schematic flow chart of a differential voltage measurement method according to an embodiment of the present application.
Detailed Description
To facilitate an understanding of the present application, the present application will now be described more fully with reference to the accompanying drawings. Embodiments of the present application are set forth 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 present 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, as used herein, the terms "first," "second," and the like may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another. 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. The first and second elements are both elements, but they are not the same element.
It is to be understood that "electrically connected" in the following embodiments is to be understood as "electrically connected", "communicatively electrically connected", and the like, if circuits, modules, units, and the like, which are electrically connected, have electrical signals or data transfer therebetween.
As used herein, the singular forms "a", "an" and "the" may include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises/comprising," "includes" or "including," etc., specify the presence of stated features, integers, steps, operations, components, parts, or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof. Also, as used in this specification, the term "and/or" includes any and all combinations of the associated listed items.
Various intelligent devices are popularized in the world at present, the intelligent degrees of the intelligent devices can not be separated from sensors with different functions, and because the electric signals acquired by the sensors are generally weak and not periodic, when the signals are processed, an amplifying circuit is required to be firstly adopted for amplifying.
In actual life and work, the application of the amplifying circuit is very wide, because the actual signal is often very weak, and the signal must be amplified to observe or drive subsequent equipment. Whether simple loudspeakers, radios, or complex, sophisticated electronic devices, often contain the basic functional circuitry of an amplifier circuit. The amplifier circuit is one of the most widely used electronic circuits, and is a basic unit circuit constituting another electronic circuit. The amplifying circuit is used for enhancing a weak electric signal to a required value by utilizing the current control action of the BJT or the voltage control action of the FET, so that the amplifying circuit is convenient for people to measure and use. The amplifying circuit can amplify an input weak signal (a signal for short, which refers to a changing voltage, current, and the like) to a required amplitude value and a signal consistent with the original input signal change rule, that is, the signal is amplified without distortion.
The differential amplifier circuit has good noise immunity, can greatly reduce signal distortion and has good output characteristics. Many integrated circuits have differential amplifier circuits as input stages. The difference value of two input ends is used as signal in the differential amplifying circuit, which mainly improves the signal precision and removes the common error interference, thus eliminating a certain error. However, the actual differential circuit is different from the ideal differential circuit, so that a common-mode signal is generated in the actual differential circuit to generate a common-mode error, in order to eliminate the common-mode error, the conventional analog circuit correction method is realized by adding a variable potentiometer into the circuit, and the common-mode error is eliminated mainly by controlling the proportion of resistors in the circuit to meet the characteristic of the ideal differential circuit.
As shown in FIG. 1, the resistance in an ideal differential voltage measurement circuit satisfies r3/r1＝r4/r2When the output voltage Vo is (V)1-V2)×r3/r1. In practice, it is difficult to meet the requirement of ideal circuit, and r is difficult to satisfy due to the error of resistance3/r1＝r4/2And the circuit is under the condition of common-mode voltage, so that the actual output voltage of the differential voltage measurement circuit is as follows:
Vo＝Kdm×Vdm+Kcm×Vcm；
wherein, Vdm＝V1-V2，VdmFor differential mode input voltage, Vcm＝(V1+V2)/2，VcmFor common mode input voltage, KdmIs a differential modulus proportionality coefficient, KcmIs the common mode proportionality coefficient, KdmAnd KcmDependent on the resistance r1Resistance r2Resistance r3And a resistance r4The common mode scaling factor may cause common mode errors in the differential voltage measurement.
For common mode errors generated in the differential voltage measurement described above, at VoIn the case of outputting digital values via an analog-to-digital converter, a digital correction method may be usedReducing common mode errors; at VoIn the case of directly outputting an analog quantity, an analog circuit correction method is required to reduce common-mode errors.
The conventional analog circuit calibration method is shown in FIG. 2, in which a resistor r is used2And a resistance r4Incorporating a variable potentiometer r24To make the variable potentiometer r24First input terminal and resistor r2Is connected to the second input terminal of the variable potentiometer r24Second input terminal and resistor r4Is connected to the second input terminal of the variable potentiometer r24Is connected with the second input end of the operational amplifier, a sliding potentiometer r24Middle resistance r2The resistance value of the direction side to the sliding contact part of the potentiometer is r24', sliding potentiometer r24Middle resistance r4The resistance value of the direction side to the sliding contact part of the potentiometer is r24Let r3/r1＝(r4+r24″)/(r2+r24') to cancel common mode errors.
Because two input ends of a variable potentiometer added by the traditional analog circuit correction method are both connected with a resistor in an original circuit, and a sliding end of the variable potentiometer is connected with a second input end of an operational amplifier, the original differential voltage measurement circuit needs to be reconnected, so that the method cannot be suitable for the condition that the positive input end and the negative input end of the operational amplifier in an integrated differential amplifier chip are in the chip; meanwhile, when high-voltage differential voltage or high-voltage common-mode voltage exists in the measured high-voltage differential voltage or the differential voltage, the working voltage added to the variable potentiometer is higher, at the moment, the digital potentiometer cannot be used, only the manual potentiometer adjustment can be used, the debugging difficulty and danger can be invisibly increased, and the debugging efficiency is reduced.
Based on the above problems, the conventional solution cannot effectively eliminate the common mode error, and the application provides a differential voltage measurement circuit aiming at two problems existing in the conventional analog circuit correction method, so that the differential voltage measurement circuit can be suitable for the condition that the positive input end and the negative input end of an operational amplifier in an integrated differential amplifier chip are in the chip on the basis of effectively eliminating the common mode error signal, and can also be applied to the measurement of high-voltage differential voltage or the high-voltage common mode voltage existing in the differential voltage, thereby increasing the flexible diversity of the output of a common mode voltage correction module, reducing the debugging difficulty and danger, and improving the debugging efficiency.
In order to explain the technical solution of the differential voltage measurement circuit in the present application, the following description is made by using specific embodiments.
In 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 correct a common-mode error according to a first voltage signal V1And a second voltage signal V2Generating a common-mode error correction signal; differential voltage measurement module 100 and the first voltage signal V1The second voltage signal V2And the common mode error correction modules 200 are connected to each other for correcting the common mode error according to the first voltage signal V1A second voltage signal V2And generating a target differential amplification voltage signal for eliminating the common mode error by the common mode error correction signal.
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 100refAfter the common-mode error correction signal passes 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 end of the differential voltage measurement module 100.
In this embodiment, the common mode error correction module 200 is electrically connected to the differential voltage measurement module 100, so that the differential voltage measurement circuit of the present invention can be effectively applied to the situation that the positive and negative input terminals of the operational amplifier in the integrated differential amplifier chip are inside the chip, and the disadvantage of adding a potentiometer in the conventional analog correction method is overcome; on the other hand, the differential voltage measuring circuit in the invention can also be applied to the situation of measuring the high-voltage differential voltage or the high-voltage common-mode voltage existing in the differential 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 purpose of eliminating the common-mode error and generating an accurate differential voltage measurement signal, so that the debugging difficulty and danger can be reduced, and the debugging efficiency is improved.
In one embodiment, as shown in fig. 4, compared to fig. 3, the apparatus further includes a summing module 300, and 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 200o2＝Kcm′×VcmAnd the analog output voltage V of the differential voltage measurement module 100o1The corrected output voltage is obtained by the summing module 300:
Vo＝Kdm×Vdm+Kcm×Vcm+Kcm′×Vcm
so that Kcm′≈-KcmThen V iso≈Kdm×VdmTherefore, the corrected output voltage V can be obtained by the common mode error correction module 200o。
In one embodiment, as shown in fig. 5, the present application provides a common mode error correction module 200, which includes a first operational amplifier OP1, a first resistor unit R1A second resistance unit R2And a third resistance unit R3Wherein the first resistance unit R1Is configured to: a first terminal and the first voltage signal V1Connected with the second terminal via a third resistance unit R3Grounding; second resistance unit R2Is configured to: first terminal and second voltage signal V2Connected with the second terminal via a third resistance unit R3Grounding; the first operational amplifier OP1 is configured to: first input terminal and first resistance unit R1Second terminal, second resistance unit R2Second terminal and third resistance unit R3The first ends of the first and second input ends are connected, the second input end is grounded, and the output end outputs a first common mode error correction signal Vo21。
Specifically, the scaling of the first operational amplifier is KampAnd R is1＝R2R, common mode errorThe difference correction module 200 outputs voltages of:
Vo21＝Vcm×Kamp×2×R3/(2×R3+R)
control Kcm′＝Kamp×2×R3/(2×R3+ R), making Kcm′≈-KcmThereby making Vo21Cancel the common mode error, in this embodiment Vo21And VcmIn phase.
Further, from Vo21Can be seen from the formula (2) for K in the present embodimentcm' is a fixed value, and can only generate V of a fixed sizecmTo accommodate K in the differential voltage measurement module 100cmChange of (3), third resistance R3Variable K can be generated using adjustable devices, e.g. adjustable potentiometers or digital potentiometerscm' to enhance the adaptability of the common mode error correction module 200.
Further, the first operational amplifier OP1 uses an adjustable gain amplifier, which can be scaled by changing the amplifier scaling KampGenerating variable Kcm' to enhance the adaptability of the common mode error correction module 200.
In one embodiment, as shown in fig. 6, compared to the embodiment shown in fig. 5, the first input terminal and the second input terminal of the first operational amplifier OP1 in this embodiment are inverted, and the second common-mode error correction signal V can be obtainedo22And a second common mode error correction signal Vo22And VcmAnd (4) 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 in this embodiment 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 arranged in sequence; wherein, the first terminal 1, the fourth terminal 4 and the first resistance unit R1Second terminal, second resistance unit R2Second terminal and third resistance unit R3Are all connected; the second terminal 2 and the third terminal 3 are both grounded; first, theOne knife is connected with the positive input end of the first operational amplifier OP 1; the second knife is connected with the inverting input end of the first operational amplifier OP 1; the common-mode error correction module 200 is further configured to: under the condition that the first knife is in contact connection with the first terminal and the second knife is in contact connection with the third terminal, a first common mode error correction signal V is outputo21(ii) a Under the condition that the first knife is in contact connection with the second terminal and the second knife is in contact connection with the fourth terminal, a second common mode error correction signal V is outputo22。
In the present embodiment, the third resistance unit R3Changing the third resistance unit R using an adjustable potentiometer or a digital potentiometer3Resistance value of, producing a varying Kcm'. When K is in the differential voltage measuring module 100cmWhen changed, the third resistance unit R is adjusted3Resistance value of, and then K is adjustedcm', let Kcm′≈-KcmThereby enabling the output voltage V of the common mode error correction module 200o2And the common mode error is counteracted to achieve the purpose of eliminating the common mode error.
In one embodiment, as shown in fig. 8, a common mode error correction module 200 is provided, which further includes a fourth resistor unit R with equal resistance value compared to fig. 64And a fifth resistance unit R5(ii) a Wherein the fourth resistance unit R4Is configured to: first terminal and first resistance unit R1Second terminal, second resistance unit R2Second terminal and third resistance unit R3Are connected, and the second terminal is connected with the first input terminal of the first operational amplifier OP 1; fifth resistance unit R5Is configured to: first terminal and fourth resistance unit R4The second end of the first operational amplifier OP1 is connected with the first input end of the first operational amplifier OP1, and the second end of the first operational amplifier OP 3578 is connected with the output end of the first operational amplifier; third resistance unit R3Is connected to a second input terminal of the first operational amplifier OP 1; by adjusting the third resistance unit R3The sliding end 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 Vo21Or a second common mode error correction signal Vo22。
Specifically, in the present embodiment, to reduce the error, the fourth resistance unit R4And a fifth resistance unit R5Is much larger than the sum of the resistance values of the third resistance unit R3The resistance value of (1); taking the third resistance unit R3The resistance from the sliding end to the end far away from the grounding end is R3', the resistance between the sliding end and the ground potential is R3Due to R4+R5Is much greater than R3Negligible flow through R4+R5Influence of the current, at this time:
when 2 XR3″<R3I.e. the third resistance unit R3When the sliding end of (A) is located between the midpoint of the potentiometer and the ground potential, KcmIs negative, Vo2Output of and VcmInverting;
when 2 XR3″>R3I.e. the third resistance unit R3When the sliding end of the potentiometer is between the midpoint of the potentiometer and the end far from the ground end, KcmIs' positive, Vo2Output of and VcmIn phase.
By sliding the third resistance unit R3The sliding end of the common mode error correction module 200 can be flexibly adjusted to output voltage Vo2So as to adapt to the change of the common-mode error and improve the debugging efficiency.
In one embodiment, a differential voltage measurement device is provided that includes a circuit as described in any of the embodiments of the present application.
The differential voltage measuring device can be used for compensating the situation that a potentiometer is added in a traditional analog circuit correcting method to eliminate the generated common mode error under the condition that the positive input end and the negative input end of an operational amplifier in a differential amplifier chip are arranged in the chip, and simultaneously can reduce the debugging difficulty and danger and improve the debugging efficiency when measuring high-voltage differential voltage or the high-voltage common mode voltage of the differential voltage.
In one embodiment, there is provided a differential voltage measurement method implemented based on the differential voltage measurement circuit described in any of the embodiments of the present application, the method including:
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 amplification 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.
The method is implemented based on any of the differential voltage measurement circuits in the embodiments of the present application, and specifically, a common mode error correction signal can be generated by controlling the common mode error correction module according to the first voltage signal and the second voltage signal, and a target differential amplified voltage signal for eliminating the common mode error can be generated by controlling the differential voltage measurement module according to the first voltage signal, the second voltage signal and the common mode error correction signal, so that the method can solve the problem of limitation of the conventional analog circuit correction method, can be used for compensating the circuit in the chip where the positive and negative input terminals of the operational amplifier in the differential amplifier chip are located, and can reduce the debugging difficulty and danger when measuring the high voltage differential voltage or the high voltage common mode voltage existing in the differential voltage, and the debugging efficiency is improved.
It should be noted that, in the embodiments provided in the present application, it should be understood that the disclosed technical content can be implemented in other ways. The above-described system embodiments are merely illustrative, and for example, the division of the units may be a logical division, and in actual implementation, there may be another division, for example, multiple units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, units or modules, and may be in an electrical or other form.
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 can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be implemented in a hardware form.
Finally, the above embodiments are only intended to illustrate the technical solutions of the present invention and not to limit the present invention, and although the present invention has been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions, and all of them should be covered by the claims of the present invention.
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;
and 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 amplification 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.
2. The circuit of claim 1, wherein the common-mode error correction module comprises 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 resistance 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 resistance 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;
wherein a resistance value of the first resistance unit is equal to a resistance value of the second resistance unit.
3. The circuit of claim 2, 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 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 terminal of the first operational amplifier is a forward input terminal and the second input terminal of the first operational amplifier is an inverting input terminal;
and outputting the second common mode error correction signal when the first input end of the first operational amplifier is a reverse input end and the second input end of the first operational amplifier is a forward input end.
4. The circuit of claim 3, wherein the common mode error correction module further comprises a selection switch, the selection switch comprising a first blade, a second blade, and a first terminal, a second terminal, a third terminal, and a fourth terminal 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 both grounded;
the first switch is connected with a positive input end of the first operational amplifier;
the second knife is connected with the inverting 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 in a case where the first blade is in contact connection with the first terminal and the second blade is in contact connection with the third terminal;
outputting the second common mode error correction signal when the first blade is in contact connection with the second terminal and the second blade is in contact connection with the fourth terminal.
5. The circuit of claim 3, wherein the common mode error correction module further comprises a fourth resistance unit and a fifth resistance unit with equal resistance values; the third resistance unit comprises an adjustable potentiometer and/or a digital potentiometer;
the fourth resistance unit is configured to: the first end of the first operational amplifier is connected with the first end of the first resistance unit, the second end of the second resistance unit and the first end of the third resistance unit;
the fifth resistance unit is configured to: the first end of the first operational amplifier is connected with the second end of the fourth resistance unit and the first input end of the first operational amplifier, and the second end of the first operational amplifier is connected with the output end of the first operational amplifier;
the sliding end of the third resistance unit is connected with the second input end of the first operational amplifier;
wherein the common mode error correction module outputs the first common mode error correction signal or the second common mode error correction signal by adjusting a position of the sliding end away from a midpoint of the adjustable potentiometer or the digital potentiometer.
6. The circuit according to any one of claims 2-4, wherein the third resistance unit comprises an adjustable potentiometer and/or a digital potentiometer;
and adjusting the adjustable potentiometer and/or the digital potentiometer to enable the amplitude of the common-mode error correction signal to be matched with the amplitude of the common-mode error of the differential voltage measurement module.
7. The circuit of any one of claims 1-5, wherein the differential voltage measurement module is configured to: and the output reference end is connected with the output end of the common-mode error correction module.
8. The circuit of any of claims 1-5, 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 amplification voltage signal.
9. A differential voltage measuring apparatus, 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;
and controlling a differential voltage measurement module to generate a target differential amplification 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.
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| CN114236221B (en) | 2023-09-26 |
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