High-precision voltage measurement system based on temperature detection

Abstract

The invention provides a high-precision voltage measurement system for temperature detection, and belongs to the technical field of voltage measurement, and the system comprises a voltage control module which is used for receiving an external input control instruction, an offset voltage and a reference voltage, controlling the switching-off or switching-on of the system based on the external input control instruction, and transmitting the offset voltage and the reference voltage, the voltage measurement circuit is electrically connected with the voltage control module and used for receiving the offset voltage, the reference voltage and the temperature detection result of the offset voltage and obtaining a high-precision voltage measurement result based on the offset voltage, the reference voltage and the temperature detection result of the offset voltage, and the temperature collection module is electrically connected with the voltage measurement circuit and used for collecting the high-precision voltage measurement result. And the temperature detection circuit is used for carrying out temperature detection on the offset voltage to obtain a temperature detection result of the offset voltage and sending the temperature detection result of the offset voltage to the voltage measurement circuit. According to the invention, by adding the voltage control module and the temperature acquisition module, the voltage measurement precision at different temperatures can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of voltage measurement, and in particular to a high-precision voltage measurement system based on temperature detection. Background Art

[0002] High-precision voltage measurement methods have always been a research hotspot in the fields of precision instruments and precision control.

[0003] Generally speaking, in order to obtain very accurate voltage measurement results, the high-precision voltage measurement method generally uses a precision op amp (offset voltage ≤ 1mV) and a high-precision ADC (measurement bit width ≥ 16bit). In order to control the error introduced in each link to be at least one order of magnitude lower than the minimum effective signal of concern, a very accurate voltage measurement result can be obtained.

[0004] However, in some application scenarios that value performance indicators such as large voltage input range, large common-mode voltage tolerance, and high bandwidth, precision op amps are sometimes not suitable, mainly because precision op amps have their own limitations and it is difficult to take into account performance indicators such as large voltage input range, large common-mode voltage tolerance, and high bandwidth. Therefore, how to use some non-precision op amps with excellent other performance indicators and improve measurement precision through some additional means is one of the difficulties of high-precision voltage measurement in specific application scenarios. There is a technical problem in the prior art that the accuracy of high-precision voltage measurement is not high. Summary of the invention

[0005] In view of this, it is necessary to provide a high-precision voltage measurement system based on temperature detection to solve the technical problem of low accuracy of high-precision voltage measurement in the prior art.

[0006] In order to solve the above technical problems, the present invention provides a high-precision voltage measurement system based on temperature detection, comprising: A voltage control module, used for receiving external input control instructions, offset voltage and reference voltage, and controlling itself to open or close and transmit the offset voltage and reference voltage based on the external input control instructions; A voltage measurement circuit is electrically connected to the voltage control module, and is used to receive the offset voltage, the reference voltage, and the temperature detection result of the offset voltage, and obtain a high-precision voltage measurement result based on the offset voltage, the reference voltage, and the temperature detection result of the offset voltage; The temperature acquisition module is electrically connected to the voltage measurement circuit, and is used to perform temperature detection on the offset voltage, obtain the temperature detection result of the offset voltage, and send the temperature detection result of the offset voltage to the voltage measurement circuit; The voltage control module includes: The first switch group is electrically connected to the second switch group and the third switch group.

[0007] In a possible implementation, the first switch group includes: The first switch is electrically connected to the second switch group and the third switch group, and is used to receive an external input control instruction and an offset voltage, and control itself to open or close and transmit the offset voltage based on the external input control instruction; The second switch is electrically connected to the second switch group and the third switch group, and is used to control itself to be opened or closed and transmit the offset voltage based on an external input control instruction.

[0008] In a possible implementation, the second switch group includes: The third switch is electrically connected to the first switch, the second switch and the third switch group, and is used to short-circuit the voltage measurement circuit.

[0009] In a possible implementation, the third switch group includes: a fourth switch, electrically connected to the first switch and the third switch, and configured to control itself to be opened or closed based on an external input control instruction, and to transmit a reference voltage; The fifth switch is electrically connected to the second switch and the fifth switch, and is used to control itself to be opened or closed based on an external input control instruction, and to transmit a reference voltage.

[0010] In a possible implementation, the system further includes: The reference voltage source module is electrically connected to the third switch group.

[0011] In a possible implementation, the voltage measurement circuit includes: An operational amplifier, wherein a positive input terminal of the operational amplifier is electrically connected to the first switch group, the second switch group and the third switch group, and a negative input terminal of the operational amplifier is electrically connected to the first switch group, the second switch group and the third switch group.

[0012] In a possible implementation, the voltage measurement circuit further includes: The filter circuit is electrically connected to the output terminal of the operational amplifier.

[0013] In a possible implementation, the voltage measurement circuit further includes: The amplifier circuit is electrically connected to the output end of the filter circuit.

[0014] In a possible implementation, the voltage measurement circuit further includes: The ADC is electrically connected to the output end of the amplifier circuit.

[0015] In a possible implementation, the voltage measurement circuit further includes: The digital processing chip and the non-volatile memory are electrically connected to the output end of the ADC.

[0016] The beneficial effects of the present invention are as follows: the high-precision voltage measurement system based on temperature detection provided by the present invention comprises: a voltage control module, which is used to receive external input control instructions, offset voltage and reference voltage, and controls itself to be disconnected or closed based on the external input control instructions and transmit the offset voltage and reference voltage; a voltage measurement circuit, which is electrically connected to the voltage control module, and is used to receive the offset voltage, the reference voltage and the temperature detection results of the offset voltage, and obtain the high-precision voltage measurement results based on the offset voltage, the reference voltage and the temperature detection results of the offset voltage; a temperature acquisition module, which is electrically connected to the voltage measurement circuit, and is used to perform temperature detection on the offset voltage, obtain the temperature detection result of the offset voltage, and send the temperature detection result of the offset voltage to the voltage measurement circuit; wherein the voltage control module comprises: a first switch group, which is electrically connected to the second switch group and the third switch group. The present invention mainly adds a voltage control module and a temperature acquisition module. By controlling the opening and closing of three switch groups in the voltage control module through an externally input control signal, the switching of different voltage sources in the circuit and the change of the circuit state can be realized. The accuracy of the voltage reference source is utilized, and the actual amplification factor of the circuit can be obtained through the reference voltage. The temperature detection of the offset voltage is performed on the offset voltage by utilizing the characteristic that the operational amplifier offset voltage changes with temperature and the temperature acquisition module. Then, a voltage measurement circuit is used to calculate the voltage measurement value based on the reference voltage and the offset voltage at different temperatures. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 A schematic diagram of the structure of an embodiment of a high-precision voltage measurement system based on temperature detection provided by the present invention; Figure 2 A circuit diagram of an embodiment of a high-precision voltage measurement system based on temperature detection provided by the present invention; Figure 3 A circuit diagram of a normal measurement state of an embodiment of a high-precision voltage measurement system based on temperature detection provided by the present invention; Figure 4 A circuit diagram of an embodiment of a high-precision voltage measurement system based on temperature detection provided by the present invention in an offset voltage correction state; Figure 5A circuit diagram of an embodiment of a high-precision voltage measurement system based on temperature detection provided by the present invention in a magnification correction state; Figure 6 A circuit diagram of an embodiment of a high-precision voltage measurement system based on temperature detection provided by the present invention in a state of offset voltage correction at different temperatures. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0020] In the description of the embodiments of the present application, unless otherwise specified, “plurality” means two or more than two.

[0021] The terms "including" and "having" and any variations thereof in the embodiments of the present invention are intended to cover non-exclusive inclusions. For example, a process, method, apparatus, product or equipment comprising a series of steps or modules is not necessarily limited to those steps or modules clearly listed, but may include other steps or modules not clearly listed or inherent to these processes, methods, products or equipment.

[0022] The naming or numbering of the steps in the embodiments of the present invention does not mean that the steps in the method flow must be executed in the time / logical sequence indicated by the naming or numbering. The execution order of the named or numbered process steps can be changed according to the technical purpose to be achieved, as long as the same or similar technical effects can be achieved.

[0023] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0024] The present invention provides a high-precision voltage measurement system based on temperature detection, which is described below.

[0025] Figure 1 A schematic diagram of an embodiment of a high-precision voltage measurement system based on temperature detection provided by the present invention and Figure 2A circuit diagram of an embodiment of a high-precision voltage measurement system based on temperature detection provided by the present invention includes: The voltage control module 110 is used to receive an external input control instruction, an offset voltage and a reference voltage, and control itself to open or close and transmit the offset voltage and the reference voltage based on the external input control instruction; The voltage measurement circuit 120 is electrically connected to the voltage control module 110, and is used to receive the offset voltage, the reference voltage, and the temperature detection result of the offset voltage, and obtain a high-precision voltage measurement result based on the offset voltage, the reference voltage, and the temperature detection result of the offset voltage; The temperature acquisition module 130 is electrically connected to the voltage measurement circuit 120 and is used to perform temperature detection on the offset voltage, obtain the temperature detection result of the offset voltage, and send the temperature detection result of the offset voltage to the voltage measurement circuit 120; The voltage control module 110 includes: The first switch group 111 is electrically connected to the second switch group 112 and the third switch group 113 .

[0026] It can be understood that the present invention discloses a high-precision voltage measurement system based on temperature detection. The system is suitable for non-precision operational amplifiers to achieve the effect of high-precision voltage measurement. It mainly utilizes the changing characteristics of the operational amplifier offset voltage, obtains the circuit offset voltage values ​​at different temperatures by short-circuiting the input measurement, and then subtracts the circuit offset voltage values ​​at different temperatures from the normal measurement value to obtain a high-precision voltage measurement value.

[0027] It can be further understood that the present invention utilizes the accuracy of the voltage reference source to obtain the actual amplification factor of the circuit. The circuit offset voltage error at different temperatures is measured and stored by utilizing the characteristic that the offset voltage of the operational amplifier changes with temperature and the on-board temperature detection chip on the circuit. During normal measurement, the circuit offset voltage error at different temperatures is subtracted from the ADC (Analog-to-Digital Converter) measurement result to obtain a high-precision voltage measurement value.

[0028] It can be further understood that, first, the first switch and the second switch are disconnected to cut off the connection between the input signal and the input side op amp to prevent the input signal from interfering with the correction; then, the fourth switch and the fifth switch are closed, and the ADC measures the error caused by the offset voltage of the op amp in the entire circuit; then, the other switches are disconnected, the fourth switch is closed, and the fixed input reference voltage VREF is input into the circuit, and the ADC measures the reference voltage multiplied by the gain and then superimposed with the error caused by the offset voltage of the op amp, and the error caused by the offset voltage of the op amp is subtracted from the calculated result to obtain the actual gain of the circuit.

[0029] The amplification factor of a circuit is generally determined by the resistance value of the resistor in the proportional amplifier circuit. Due to the error of the resistor itself, the actual amplification factor will be slightly different from the set amplification factor. However, for a certain actual circuit, the resistance value is always certain and is not affected by temperature within the operating temperature range. Since its actual amplification factor is certain, the actual amplification factor only needs to be measured once.

[0030] However, the offset voltage of the op amp is greatly affected by temperature. Therefore, the offset voltage needs to be measured under different temperature conditions. The best temperature measurement condition is to perform a temperature cycle from the lowest operating temperature to the highest operating temperature, so that the offset voltage corresponding to each temperature point can be measured. In this way, there is no need to switch the switch during the normal measurement of the circuit. If there is no condition for temperature cycling, then a set of temperature switching values ​​needs to be set manually. When the temperature reaches the switching value, switch the switch to measure the offset voltage at this temperature. The offset voltage of each temperature value only needs to be measured once.

[0031] The measurement results of the actual amplification factor and the offset voltage at each temperature are stored in a non-volatile memory (such as FLASH or EEPROM) inside or outside the digital processing chip.

[0032] The system proposed in the present invention does not make any changes to the traditional measurement circuit. It only adds five switches, a reference voltage source module and an on-board temperature acquisition chip to achieve high-precision voltage measurement. The control logic is simple and only the switch needs to be switched once at the new operating temperature.

[0033] In some embodiments of the present invention, the first switch group 111 includes: The first switch is electrically connected to the second switch group 112 and the third switch group 113, and is used to receive an external input control instruction and an offset voltage, and control itself to open or close and transmit the offset voltage based on the external input control instruction; The second switch is electrically connected to the second switch group 112 and the third switch group 113 , and is used to control itself to be opened or closed and transmit the offset voltage based on an external input control instruction.

[0034] It can be understood that the present invention discloses a high-precision voltage measurement system based on temperature detection. The system is suitable for non-precision operational amplifiers to achieve the effect of high-precision voltage measurement. It mainly utilizes the changing characteristics of the operational amplifier offset voltage, obtains the circuit offset voltage values ​​at different temperatures by short-circuiting the input measurement, and then subtracts the circuit offset voltage values ​​at different temperatures from the normal measurement value to obtain a high-precision voltage measurement value.

[0035] It can be further understood that the present invention utilizes the accuracy of the voltage reference source to obtain the actual amplification factor of the circuit. The circuit offset voltage error at different temperatures is measured and stored by utilizing the characteristic that the operational amplifier offset voltage changes with temperature and the on-board temperature detection chip on the circuit. During normal measurement, the circuit offset voltage error at different temperatures is subtracted from the ADC measurement result to obtain a high-precision voltage measurement value.

[0036] In some embodiments of the present invention, the second switch group 112 includes: The third switch is electrically connected to the first switch, the second switch and the third switch group 113 , and is used to short-circuit the voltage measurement circuit 120 .

[0037] It can be understood that the present invention discloses a high-precision voltage measurement system based on temperature detection. The system is suitable for non-precision operational amplifiers to achieve the effect of high-precision voltage measurement. It mainly utilizes the changing characteristics of the operational amplifier offset voltage, obtains the circuit offset voltage values ​​at different temperatures by short-circuiting the input measurement, and then subtracts the circuit offset voltage values ​​at different temperatures from the normal measurement value to obtain a high-precision voltage measurement value.

[0038] It can be further understood that the present invention utilizes the accuracy of the voltage reference source to obtain the actual amplification factor of the circuit. The circuit offset voltage error at different temperatures is measured and stored by utilizing the characteristic that the operational amplifier offset voltage changes with temperature and the on-board temperature detection chip on the circuit. During normal measurement, the circuit offset voltage error at different temperatures is subtracted from the ADC measurement result to obtain a high-precision voltage measurement value.

[0039] It can be further understood that, first, the first switch and the second switch are disconnected to cut off the connection between the input signal and the input side op amp to prevent the input signal from interfering with the correction; then, the fourth switch and the fifth switch are closed, and the ADC measures the error caused by the offset voltage of the op amp in the entire circuit; then, the other switches are disconnected, the fourth switch is closed, and the fixed input reference voltage VREF is input into the circuit, and the ADC measures the reference voltage multiplied by the gain and then superimposed with the error caused by the offset voltage of the op amp, and the error caused by the offset voltage of the op amp is subtracted from the calculated result to obtain the actual gain of the circuit.

[0040] The amplification factor of a circuit is generally determined by the resistance value of the resistor in the proportional amplifier circuit. Due to the error of the resistor itself, the actual amplification factor will be slightly different from the set amplification factor. However, for a certain actual circuit, the resistance value is always certain and is not affected by temperature within the operating temperature range. Since its actual amplification factor is certain, the actual amplification factor only needs to be measured once.

[0041] In some embodiments of the present invention, the third switch group 113 includes: a fourth switch, electrically connected to the first switch and the third switch, and configured to control itself to be opened or closed based on an external input control instruction, and to transmit a reference voltage; The fifth switch is electrically connected to the second switch and the fifth switch, and is used to control itself to be opened or closed based on an external input control instruction, and to transmit a reference voltage.

[0042] It can be understood that the present invention discloses a high-precision voltage measurement system based on temperature detection. The system is suitable for non-precision operational amplifiers to achieve the effect of high-precision voltage measurement. It mainly utilizes the changing characteristics of the operational amplifier offset voltage, obtains the circuit offset voltage values ​​at different temperatures by short-circuiting the input measurement, and then subtracts the circuit offset voltage values ​​at different temperatures from the normal measurement value to obtain a high-precision voltage measurement value.

[0043] It can be further understood that the present invention utilizes the accuracy of the voltage reference source to obtain the actual amplification factor of the circuit. The circuit offset voltage error at different temperatures is measured and stored by utilizing the characteristic that the operational amplifier offset voltage changes with temperature and the on-board temperature detection chip on the circuit. During normal measurement, the circuit offset voltage error at different temperatures is subtracted from the ADC measurement result to obtain a high-precision voltage measurement value.

[0044] It can be further understood that, first, the first switch and the second switch are disconnected to cut off the connection between the input signal and the input side op amp to prevent the input signal from interfering with the correction; then, the fourth switch and the fifth switch are closed, and the ADC measures the error caused by the offset voltage of the op amp in the entire circuit; then, the other switches are disconnected, the fourth switch is closed, and the fixed input reference voltage VREF is input into the circuit, and the ADC measures the reference voltage multiplied by the gain and then superimposed with the error caused by the offset voltage of the op amp, and the error caused by the offset voltage of the op amp is subtracted from the calculated result to obtain the actual gain of the circuit.

[0045] The circuit amplification factor is generally determined by the resistance value of the resistor in the proportional amplifier circuit. Due to the resistance error itself, the actual amplification factor will be slightly different from the set amplification factor. However, for a certain actual circuit, the resistance value is always certain and is not affected by temperature within the operating temperature range. Since its actual amplification factor is certain, the actual amplification factor only needs to be measured once.

[0046] In some embodiments of the present invention, the system further comprises: The reference voltage source module is electrically connected to the third switch group 113 .

[0047] It can be understood that the present invention discloses a high-precision voltage measurement system based on temperature detection. The system is suitable for non-precision operational amplifiers to achieve the effect of high-precision voltage measurement. It mainly utilizes the changing characteristics of the operational amplifier offset voltage, obtains the circuit offset voltage values ​​at different temperatures by short-circuiting the input measurement, and then subtracts the circuit offset voltage values ​​at different temperatures from the normal measurement value to obtain a high-precision voltage measurement value.

[0048] It can be further understood that the present invention utilizes the accuracy of the voltage reference source to obtain the actual amplification factor of the circuit. The circuit offset voltage error at different temperatures is measured and stored by utilizing the characteristic that the operational amplifier offset voltage changes with temperature and the on-board temperature detection chip on the circuit. During normal measurement, the circuit offset voltage error at different temperatures is subtracted from the ADC measurement result to obtain a high-precision voltage measurement value.

[0049] In some embodiments of the present invention, the voltage measurement circuit 120 includes: An operational amplifier, wherein a positive input terminal of the operational amplifier is electrically connected to the first switch group 111 , the second switch group 112 , and the third switch group 113 , and a negative input terminal of the operational amplifier is electrically connected to the first switch group 111 , the second switch group 112 , and the third switch group 113 .

[0050] It can be understood that the present invention discloses a high-precision voltage measurement system based on temperature detection. The system is suitable for non-precision operational amplifiers to achieve the effect of high-precision voltage measurement. It mainly utilizes the changing characteristics of the operational amplifier offset voltage, obtains the circuit offset voltage values ​​at different temperatures by short-circuiting the input measurement, and then subtracts the circuit offset voltage values ​​at different temperatures from the normal measurement value to obtain a high-precision voltage measurement value.

[0051] It can be further understood that the present invention utilizes the accuracy of the voltage reference source to obtain the actual amplification factor of the circuit. The circuit offset voltage error at different temperatures is measured and stored by utilizing the characteristic that the operational amplifier offset voltage changes with temperature and the on-board temperature detection chip on the circuit. During normal measurement, the circuit offset voltage error at different temperatures is subtracted from the ADC measurement result to obtain a high-precision voltage measurement value.

[0052] In some embodiments of the present invention, the voltage measurement circuit 120 further includes: The filter circuit is electrically connected to the output terminal of the operational amplifier.

[0053] It can be understood that the present invention discloses a high-precision voltage measurement system based on temperature detection. The system is suitable for non-precision operational amplifiers to achieve the effect of high-precision voltage measurement. It mainly utilizes the changing characteristics of the operational amplifier offset voltage, obtains the circuit offset voltage values ​​at different temperatures by short-circuiting the input measurement, and then subtracts the circuit offset voltage values ​​at different temperatures from the normal measurement value to obtain a high-precision voltage measurement value.

[0054] It can be further understood that the present invention utilizes the accuracy of the voltage reference source to obtain the actual amplification factor of the circuit. The circuit offset voltage error at different temperatures is measured and stored by utilizing the characteristic that the operational amplifier offset voltage changes with temperature and the on-board temperature detection chip on the circuit. During normal measurement, the circuit offset voltage error at different temperatures is subtracted from the ADC measurement result to obtain a high-precision voltage measurement value.

[0055] In some embodiments of the present invention, the voltage measurement circuit 120 further includes: The amplifier circuit is electrically connected to the output end of the filter circuit.

[0056] It can be understood that the present invention discloses a high-precision voltage measurement system based on temperature detection. The system is suitable for non-precision operational amplifiers to achieve the effect of high-precision voltage measurement. It mainly utilizes the changing characteristics of the operational amplifier offset voltage, obtains the circuit offset voltage values ​​at different temperatures by short-circuiting the input measurement, and then subtracts the circuit offset voltage values ​​at different temperatures from the normal measurement value to obtain a high-precision voltage measurement value.

[0057] It can be further understood that the present invention utilizes the accuracy of the voltage reference source to obtain the actual amplification factor of the circuit. The circuit offset voltage error at different temperatures is measured and stored by utilizing the characteristic that the operational amplifier offset voltage changes with temperature and the on-board temperature detection chip on the circuit. During normal measurement, the circuit offset voltage error at different temperatures is subtracted from the ADC measurement result to obtain a high-precision voltage measurement value.

[0058] In some embodiments of the present invention, the voltage measurement circuit 120 further includes: The ADC is electrically connected to the output end of the amplifier circuit.

[0059] It can be understood that the present invention discloses a high-precision voltage measurement system based on temperature detection. The system is suitable for non-precision operational amplifiers to achieve the effect of high-precision voltage measurement. It mainly utilizes the changing characteristics of the operational amplifier offset voltage, obtains the circuit offset voltage values ​​at different temperatures by short-circuiting the input measurement, and then subtracts the circuit offset voltage values ​​at different temperatures from the normal measurement value to obtain a high-precision voltage measurement value.

[0060] It can be further understood that the present invention utilizes the accuracy of the voltage reference source to obtain the actual amplification factor of the circuit. The circuit offset voltage error at different temperatures is measured and stored by utilizing the characteristic that the operational amplifier offset voltage changes with temperature and the on-board temperature detection chip on the circuit. During normal measurement, the circuit offset voltage error at different temperatures is subtracted from the ADC measurement result to obtain a high-precision voltage measurement value.

[0061] In some embodiments of the present invention, the voltage measurement circuit 120 further includes: The digital processing chip and the non-volatile memory are electrically connected to the output end of the ADC.

[0062] It can be understood that the present invention discloses a high-precision voltage measurement system based on temperature detection. The system is suitable for non-precision operational amplifiers to achieve the effect of high-precision voltage measurement. It mainly utilizes the changing characteristics of the operational amplifier offset voltage, obtains the circuit offset voltage values ​​at different temperatures by short-circuiting the input measurement, and then subtracts the circuit offset voltage values ​​at different temperatures from the normal measurement value to obtain a high-precision voltage measurement value.

[0063] It can be further understood that the present invention utilizes the accuracy of the voltage reference source to obtain the actual amplification factor of the circuit. The circuit offset voltage error at different temperatures is measured and stored by utilizing the characteristic that the operational amplifier offset voltage changes with temperature and the on-board temperature detection chip on the circuit. During normal measurement, the circuit offset voltage error at different temperatures is subtracted from the ADC measurement result to obtain a high-precision voltage measurement value.

[0064] Figure 3 A circuit diagram of a normal measurement state of an embodiment of a high-precision voltage measurement system based on temperature detection provided by the present invention includes: It can be understood that, in one embodiment of the present invention, the switches S1 and S2 are closed, and the switches S3, S4, and S5 are opened, and the circuit works as follows: Figure 3 The status at this time is the normal measurement status.

[0065] Figure 4 A circuit diagram of an embodiment of a high-precision voltage measurement system based on temperature detection provided by the present invention in an offset voltage correction state includes: It can be understood that, in one embodiment of the present invention, switches S1, S2, S4, and S5 are all disconnected, and S3 is closed. At this time, the positive and negative terminals of the input operational amplifier are directly connected, so that the input is 0. This measurement condition is offset voltage correction, such as Figure 4 As shown. There are: ; in, To adjust the voltage to correct the ADC measurement results under measurement conditions, The temperature of the board measured by the temperature detection chip on the board (the temperature detection chip on the board is arranged close to the operational amplifier of the analog circuit, and the temperature of all operational amplifiers on the board is almost the same as the temperature of the board surface). is the offset voltage of the input op amp, is the offset voltage of the filter circuit op amp, is the offset voltage of the amplifier circuit op amp, Nx=R2 / R1 is the circuit amplification factor. When there are more than three op amps in the signal processing circuit, the expression needs to be adjusted accordingly.

[0066] Figure 5 A circuit diagram of an embodiment of a high-precision voltage measurement system based on temperature detection provided by the present invention in a magnification correction state includes: It can be understood that, in one embodiment of the present invention, switches S1, S2, and S3 are opened, and switches S4 and S5 are closed. At this time, the input is a fixed value Vref. This measurement condition is a magnification correction. Figure 5 As shown. Generally, a voltage reference chip is used as a fixed voltage source. The output voltage of this chip is very stable (usually the error is less than 0.05%), and the voltage deviation can be considered to be 0. There are: ; in, is the ADC measurement result under the measurement condition of amplification correction. Obviously, there is: , Vref is known, from which the circuit magnification can be obtained The accurate value of the resistor can be obtained, thereby eliminating the circuit amplification error caused by the resistor error. Because the resistor value does not change with temperature, this measurement condition only needs to be measured once. It should be noted that when there is no amplifier circuit, the reference voltage source Vref and switches S4 and S5 are not required in the circuit, and the amplification factor is 1.

[0067] Figure 6 A circuit diagram of an embodiment of a high-precision voltage measurement system based on temperature detection provided by the present invention in an offset voltage correction state at different temperatures includes: It is understandable that when the temperature changes, the offset voltage of the op amp will also change accordingly. At this time, it is necessary to re-calibrate the offset voltage and measure or , get the corresponding V1 value at each temperature, and save it in the non-volatile memory in circuit 1, such as Figure 6 shown.

[0068] When the circuit is in the normal measurement state, there are: ; in, is the measured value of ADC, it can be inferred that: When the measured values ​​at various temperatures are Finally, by applying this formula, you can get accurate input voltage measurement results.

[0069] The high-precision voltage measurement system based on temperature detection provided by the present invention is introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A high-precision voltage measurement system based on temperature detection, characterized in that: include: A voltage control module, used for receiving external input control instructions, offset voltage and reference voltage, and controlling itself to open or close and transmit the offset voltage and reference voltage based on the external input control instructions; A voltage measurement circuit is electrically connected to the voltage control module, and is used to receive the offset voltage, the reference voltage, and the temperature detection result of the offset voltage, and obtain a high-precision voltage measurement result based on the offset voltage, the reference voltage, and the temperature detection result of the offset voltage; The temperature acquisition module is electrically connected to the voltage measurement circuit, and is used to perform temperature detection on the offset voltage, obtain the temperature detection result of the offset voltage, and send the temperature detection result of the offset voltage to the voltage measurement circuit; The voltage control module includes: The first switch group is electrically connected to the second switch group and the third switch group.

2. The high-precision voltage measurement system based on temperature detection according to claim 1, characterized in that: The first switch group includes: The first switch is electrically connected to the second switch group and the third switch group, and is used to receive an external input control instruction and an offset voltage, and control itself to open or close and transmit the offset voltage based on the external input control instruction; The second switch is electrically connected to the second switch group and the third switch group, and is used to control itself to be opened or closed and transmit the offset voltage based on an external input control instruction.

3. The high-precision voltage measurement system based on temperature detection according to claim 1 or 2, characterized in that: The second switch group includes: The third switch is electrically connected to the first switch, the second switch and the third switch group, and is used to short-circuit the voltage measurement circuit.

4. The high-precision voltage measurement system based on temperature detection according to claim 1 or 3, characterized in that: The third switch group comprises: a fourth switch, electrically connected to the first switch and the third switch, and configured to control itself to be opened or closed based on an external input control instruction, and to transmit a reference voltage; The fifth switch is electrically connected to the second switch and the fifth switch, and is used to control itself to be opened or closed based on an external input control instruction, and to transmit a reference voltage.

5. The high-precision voltage measurement system based on temperature detection according to claim 1, characterized in that: The system further comprises: The reference voltage source module is electrically connected to the third switch group.

6. The high-precision voltage measurement system based on temperature detection according to claim 1, characterized in that: The voltage measurement circuit comprises: An operational amplifier, wherein a positive input terminal of the operational amplifier is electrically connected to the first switch group, the second switch group and the third switch group, and a negative input terminal of the operational amplifier is electrically connected to the first switch group, the second switch group and the third switch group.

7. The high-precision voltage measurement system based on temperature detection according to claim 6, characterized in that: The voltage measurement circuit further includes: The filter circuit is electrically connected to the output terminal of the operational amplifier.

8. The high-precision voltage measurement system based on temperature detection according to claim 7, characterized in that: The voltage measurement circuit further includes: The amplifier circuit is electrically connected to the output end of the filter circuit.

9. The high-precision voltage measurement system based on temperature detection according to claim 8, characterized in that: The voltage measurement circuit further includes: The ADC is electrically connected to the output end of the amplifier circuit.

10. The high-precision voltage measurement system based on temperature detection according to claim 9, characterized in that: The voltage measurement circuit further includes: The digital processing chip and the non-volatile memory are electrically connected to the output end of the ADC.

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