High-precision voltage measurement system based on temperature detection

Abstract

The application provides a high-precision voltage measurement system for temperature detection, and belongs to the technical field of voltage measurement. The system comprises a voltage control module, a voltage measurement circuit and a temperature acquisition module. The voltage control module is used for receiving external input control instructions, an offset voltage and a reference voltage, controlling itself to be disconnected or closed based on the external input control instructions, and transmitting the offset voltage and the reference voltage. The voltage measurement circuit is electrically connected with the voltage control module, used for receiving the offset voltage, the reference voltage and a 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. The temperature acquisition module is electrically connected with the voltage measurement circuit, used for performing temperature detection on the offset voltage to obtain the temperature detection result of the offset voltage, and sending the temperature detection result of the offset voltage to the voltage measurement circuit. The voltage control module and the temperature acquisition module are newly added, so that the voltage measurement precision under different temperatures can be improved.

Description

Technical Field

[0001] This invention relates to the field of voltage measurement technology, and more specifically to a high-precision voltage measurement system based on temperature detection. Background Technology

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

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

[0004] However, in applications that prioritize performance indicators such as large input voltage range, large common-mode voltage withstand capability, and high bandwidth, precision operational amplifiers (op-amps) are sometimes unsuitable. This is mainly because precision op-amps have inherent limitations and cannot simultaneously achieve these performance requirements. Therefore, finding suitable non-precision op-amps with superior performance and employing additional methods to improve measurement accuracy is one of the challenges in high-precision voltage measurement for specific applications. Existing technologies suffer from insufficient accuracy in high-precision voltage measurements. 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 in high-precision voltage measurement in the prior art.

[0006] To address the aforementioned technical problems, this invention provides a high-precision voltage measurement system based on temperature detection, comprising:

[0007] The voltage control module is used to receive external input control commands, offset voltage and reference voltage, and control itself to open or close based on the external input control commands and transmit offset voltage and reference voltage;

[0008] The voltage measurement circuit, electrically connected to the voltage control module, is used to receive the offset voltage, reference voltage, and temperature detection results of the offset voltage, and to obtain high-precision voltage measurement results based on the offset voltage, reference voltage, and temperature detection results of the offset voltage.

[0009] The temperature acquisition module is electrically connected to the voltage measurement circuit. It is used to detect the temperature of 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.

[0010] The voltage control module includes:

[0011] The first switch group is electrically connected to the second and third switch groups.

[0012] In one possible implementation, the first switch group includes:

[0013] The first switch is electrically connected to the second and third switch groups and is used to receive external input control commands and offset voltages, and control itself to open or close and transmit offset voltages based on the external input control commands.

[0014] The second switch, electrically connected to the second and third switch groups, is used to control its own opening or closing and to transmit offset voltage based on external input control commands.

[0015] In one possible implementation, the second switch group includes:

[0016] The third switch is electrically connected to the first, second, and third switch groups and is used to short-circuit the voltage measurement circuit.

[0017] In one possible implementation, the third switch group includes:

[0018] The fourth switch, electrically connected to the first and third switches, is used to control its own opening or closing based on external input control commands and to transmit a reference voltage;

[0019] The fifth switch, electrically connected to the second and fifth switches, is used to control its own opening or closing based on external input control commands and to transmit a reference voltage.

[0020] In one possible implementation, the system further includes:

[0021] The reference voltage source module is electrically connected to the third switch group.

[0022] In one possible implementation, the voltage measurement circuit includes:

[0023] An operational amplifier, the positive input terminal of which is electrically connected to the first switch group, the second switch group and the third switch group, and the inverting input terminal of which is electrically connected to the first switch group, the second switch group and the third switch group.

[0024] In one possible implementation, the voltage measurement circuit further includes:

[0025] The filter circuit is electrically connected to the output of the operational amplifier.

[0026] In one possible implementation, the voltage measurement circuit further includes:

[0027] The amplifier circuit is electrically connected to the output terminal of the filter circuit.

[0028] In one possible implementation, the voltage measurement circuit further includes:

[0029] The ADC is electrically connected to the output terminal of the amplifier circuit.

[0030] In one possible implementation, the voltage measurement circuit further includes:

[0031] The digital processing chip and non-volatile memory are electrically connected to the output of the ADC.

[0032] The beneficial effects of this invention are as follows: The high-precision voltage measurement system based on temperature detection provided by this invention includes: a voltage control module, used to receive external input control commands, offset voltage, and reference voltage, and control itself to open or close based on the external input control commands and transmit the offset voltage and reference voltage; a voltage measurement circuit, electrically connected to the voltage control module, used to receive the offset voltage, reference voltage, and temperature detection results of the offset voltage, and obtain a high-precision voltage measurement result based on the temperature detection results of the offset voltage, reference voltage, and offset voltage; a temperature acquisition module, electrically connected to the voltage measurement circuit, 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 includes: a first switch group, electrically connected to a second switch group and a third switch group. This 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 externally input control signals, the switching of different voltage sources and the change of circuit state can be realized. By utilizing the accuracy of the voltage reference source, the actual amplification factor of the circuit can be obtained through the reference voltage. By utilizing the characteristics of the operational amplifier offset voltage changing with temperature and the temperature acquisition module to detect the temperature of the offset voltage, a high-precision voltage measurement value is obtained by the voltage measurement circuit based on the reference voltage and the offset voltage at different temperatures. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying 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 effort.

[0034] Figure 1 This is a schematic diagram of an embodiment of the high-precision voltage measurement system based on temperature detection provided by the present invention;

[0035] Figure 2 A circuit diagram of an embodiment of the high-precision voltage measurement system based on temperature detection provided by the present invention;

[0036] Figure 3 A circuit diagram of a high-precision voltage measurement system based on temperature detection provided by the present invention under normal measurement conditions;

[0037] Figure 4 A circuit diagram of the offset voltage correction state of an embodiment of the high-precision voltage measurement system based on temperature detection provided by the present invention;

[0038] Figure 5 A circuit diagram of the high-precision voltage measurement system based on temperature detection provided by the present invention under the amplification factor correction state in one embodiment;

[0039] Figure 6 The circuit diagram shows the offset voltage correction state at different temperatures in an embodiment of the high-precision voltage measurement system based on temperature detection provided by the present invention. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0041] In the description of the embodiments of this application, unless otherwise stated, "a plurality of" means two or more.

[0042] In this embodiment of the invention, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, apparatus, product or device that includes a series of steps or modules is not necessarily limited to those steps or modules that are explicitly listed, but may include other steps or modules that are not explicitly listed or that are inherent to such process, method, product or device.

[0043] The naming or numbering of 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 order 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 effect can be achieved.

[0044] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0045] This invention provides a high-precision voltage measurement system based on temperature detection, which will be described in detail below.

[0046] Figure 1 A schematic diagram of an embodiment of the high-precision voltage measurement system based on temperature detection provided by the present invention. Figure 2 A circuit diagram of an embodiment of the high-precision voltage measurement system based on temperature detection provided by the present invention includes:

[0047] Voltage control module 110 is used to receive external input control commands, offset voltage and reference voltage, and control itself to open or close based on external input control commands and transmit offset voltage and reference voltage;

[0048] 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 results of the offset voltage, and to obtain high-precision voltage measurement results based on the offset voltage, the reference voltage, and the temperature detection results of the offset voltage.

[0049] The temperature acquisition module 130 is electrically connected to the voltage measurement circuit 120 and is used to detect the temperature of 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.

[0050] The voltage control module 110 includes:

[0051] The first switch group 111 is electrically connected to the second switch group 112 and the third switch group 113.

[0052] It is understood that the present invention discloses a high-precision voltage measurement system based on temperature detection. This system is applicable to non-precision operational amplifiers to achieve the effect of high-precision voltage measurement. It mainly utilizes the variation characteristics of operational amplifier offset voltage. By shorting the input, the circuit offset voltage value at different temperatures is obtained. Then, the normal measurement value is subtracted from the circuit offset voltage value at different temperatures to obtain a high-precision voltage measurement value.

[0053] It can be further understood that this invention utilizes the accuracy of the voltage reference source to obtain the actual amplification factor of the circuit. By leveraging the temperature-dependent characteristics of the operational amplifier offset voltage and the on-board temperature detection chip, the circuit offset voltage error at different temperatures is measured and stored. During normal measurement, subtracting the circuit offset voltage error at different temperatures from the ADC (Analog-to-Digital Converter) measurement result yields a high-precision voltage measurement value.

[0054] To further understand this, firstly, the first and second switches are disconnected, cutting off the connection between the input signal and the input-side op-amp to prevent the input signal from interfering with the calibration. Then, the fourth and fifth switches are closed. At this point, the ADC measures the error caused by the op-amp offset voltage in the entire circuit. Next, the other switches are disconnected, and the fourth switch is closed, inputting a fixed input reference voltage VREF into the circuit. At this point, the ADC measures the error caused by the op-amp offset voltage, which is the reference voltage multiplied by the amplification factor and then superimposed. The actual amplification factor of the circuit is obtained by subtracting the error caused by the op-amp offset voltage from the calculated result.

[0055] The amplification factor of a circuit is generally determined by the resistance value of the proportional amplifier circuit. Due to the inherent error of the resistor, the actual amplification factor will differ slightly from the set amplification factor. However, for a given actual circuit, the resistance value is always fixed and is not affected by temperature within the operating temperature range. Since its actual amplification factor is fixed, the actual amplification factor only needs to be measured once.

[0056] However, the offset voltage of an operational amplifier (op-amp) is significantly affected by temperature. Therefore, offset voltage measurements need to be performed under different temperature conditions. The best temperature measurement condition is a temperature cycle from the lowest to the highest operating temperature. This allows for measurement of the offset voltage at each temperature point, eliminating the need to switch the switch during normal circuit measurements. If a temperature cycle is not possible, a set of temperature switching values ​​needs to be manually set. When the temperature reaches the switching value, the switch is toggled to measure the offset voltage at that temperature. The offset voltage at each temperature only needs to be measured once.

[0057] The actual amplification factor measurement and the offset voltage measurement results at various temperatures are stored in non-volatile memory (such as FLASH or EEPROM) inside or outside the digital processing chip.

[0058] The system proposed in this 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 requires switching the switches once at the new operating temperature.

[0059] In some embodiments of the present invention, the first switch group 111 includes:

[0060] The first switch is electrically connected to the second switch group 112 and the third switch group 113, and is used to receive external input control commands and offset voltage, and control itself to open or close and transmit offset voltage based on the external input control commands.

[0061] The second switch, electrically connected to the second switch group 112 and the third switch group 113, is used to control itself to open or close and transmit offset voltage based on external input control commands.

[0062] It is understood that the present invention discloses a high-precision voltage measurement system based on temperature detection. This system is applicable to non-precision operational amplifiers to achieve the effect of high-precision voltage measurement. It mainly utilizes the variation characteristics of operational amplifier offset voltage. By shorting the input, the circuit offset voltage value at different temperatures is obtained. Then, the normal measurement value is subtracted from the circuit offset voltage value at different temperatures to obtain a high-precision voltage measurement value.

[0063] It can be further understood that this invention utilizes the accuracy of the voltage reference source to obtain the actual amplification factor of the circuit. By leveraging the temperature-dependent characteristics of the operational amplifier offset voltage and the on-board temperature detection chip, the circuit offset voltage error at different temperatures is measured and stored. During normal measurement, subtracting the circuit offset voltage error at different temperatures from the ADC measurement result yields a high-precision voltage measurement value.

[0064] In some embodiments of the present invention, the second switch group 112 includes:

[0065] 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.

[0066] It is understood that the present invention discloses a high-precision voltage measurement system based on temperature detection. This system is applicable to non-precision operational amplifiers to achieve the effect of high-precision voltage measurement. It mainly utilizes the variation characteristics of operational amplifier offset voltage. By shorting the input, the circuit offset voltage value at different temperatures is obtained. Then, the normal measurement value is subtracted from the circuit offset voltage value at different temperatures to obtain a high-precision voltage measurement value.

[0067] It can be further understood that this invention utilizes the accuracy of the voltage reference source to obtain the actual amplification factor of the circuit. By leveraging the temperature-dependent characteristics of the operational amplifier offset voltage and the on-board temperature detection chip, the circuit offset voltage error at different temperatures is measured and stored. During normal measurement, subtracting the circuit offset voltage error at different temperatures from the ADC measurement result yields a high-precision voltage measurement value.

[0068] To further understand this, firstly, the first and second switches are disconnected, cutting off the connection between the input signal and the input-side op-amp to prevent the input signal from interfering with the calibration. Then, the fourth and fifth switches are closed. At this point, the ADC measures the error caused by the op-amp offset voltage in the entire circuit. Next, the other switches are disconnected, and the fourth switch is closed, inputting a fixed input reference voltage VREF into the circuit. At this point, the ADC measures the error caused by the op-amp offset voltage, which is the reference voltage multiplied by the amplification factor and then superimposed. The actual amplification factor of the circuit is obtained by subtracting the error caused by the op-amp offset voltage from the calculated result.

[0069] The amplification factor of a circuit is generally determined by the resistance value of the proportional amplifier circuit. Due to the inherent error of the resistor, the actual amplification factor will differ slightly from the set amplification factor. However, for a given actual circuit, the resistance value is always fixed and is not affected by temperature within the operating temperature range. Since its actual amplification factor is fixed, the actual amplification factor only needs to be measured once.

[0070] In some embodiments of the present invention, the third switch group 113 includes:

[0071] The fourth switch, electrically connected to the first and third switches, is used to control its own opening or closing based on external input control commands and to transmit a reference voltage;

[0072] The fifth switch, electrically connected to the second and fifth switches, is used to control its own opening or closing based on external input control commands and to transmit a reference voltage.

[0073] It is understood that the present invention discloses a high-precision voltage measurement system based on temperature detection. This system is applicable to non-precision operational amplifiers to achieve the effect of high-precision voltage measurement. It mainly utilizes the variation characteristics of operational amplifier offset voltage. By shorting the input, the circuit offset voltage value at different temperatures is obtained. Then, the normal measurement value is subtracted from the circuit offset voltage value at different temperatures to obtain a high-precision voltage measurement value.

[0074] It can be further understood that this invention utilizes the accuracy of the voltage reference source to obtain the actual amplification factor of the circuit. By leveraging the temperature-dependent characteristics of the operational amplifier offset voltage and the on-board temperature detection chip, the circuit offset voltage error at different temperatures is measured and stored. During normal measurement, subtracting the circuit offset voltage error at different temperatures from the ADC measurement result yields a high-precision voltage measurement value.

[0075] To further understand this, firstly, the first and second switches are disconnected, cutting off the connection between the input signal and the input-side op-amp to prevent the input signal from interfering with the calibration. Then, the fourth and fifth switches are closed. At this point, the ADC measures the error caused by the op-amp offset voltage in the entire circuit. Next, the other switches are disconnected, and the fourth switch is closed, inputting a fixed input reference voltage VREF into the circuit. At this point, the ADC measures the error caused by the op-amp offset voltage, which is the reference voltage multiplied by the amplification factor and then superimposed. The actual amplification factor of the circuit is obtained by subtracting the error caused by the op-amp offset voltage from the calculated result.

[0076] The amplification factor of a circuit is generally determined by the resistance value of the proportional amplifier circuit in the circuit. Due to the inherent error of the resistor, the actual amplification factor will be slightly different from the set amplification factor. However, for a specific actual circuit, the resistance value is always fixed and is not affected by temperature within the operating temperature range. Since its actual amplification factor is fixed, the actual amplification factor only needs to be measured once.

[0077] In some embodiments of the present invention, the system further includes:

[0078] The reference voltage source module is electrically connected to the third switch group 113.

[0079] It is understood that the present invention discloses a high-precision voltage measurement system based on temperature detection. This system is applicable to non-precision operational amplifiers to achieve the effect of high-precision voltage measurement. It mainly utilizes the variation characteristics of operational amplifier offset voltage. By shorting the input, the circuit offset voltage value at different temperatures is obtained. Then, the normal measurement value is subtracted from the circuit offset voltage value at different temperatures to obtain a high-precision voltage measurement value.

[0080] It can be further understood that this invention utilizes the accuracy of the voltage reference source to obtain the actual amplification factor of the circuit. By leveraging the temperature-dependent characteristics of the operational amplifier offset voltage and the on-board temperature detection chip, the circuit offset voltage error at different temperatures is measured and stored. During normal measurement, subtracting the circuit offset voltage error at different temperatures from the ADC measurement result yields a high-precision voltage measurement value.

[0081] In some embodiments of the present invention, the voltage measurement circuit 120 includes:

[0082] An operational amplifier is provided, with its positive input terminal electrically connected to the first switch group 111, the second switch group 112, and the third switch group 113, and its inverting input terminal electrically connected to the first switch group 111, the second switch group 112, and the third switch group 113.

[0083] It is understood that the present invention discloses a high-precision voltage measurement system based on temperature detection. This system is applicable to non-precision operational amplifiers to achieve the effect of high-precision voltage measurement. It mainly utilizes the variation characteristics of operational amplifier offset voltage. By shorting the input, the circuit offset voltage value at different temperatures is obtained. Then, the normal measurement value is subtracted from the circuit offset voltage value at different temperatures to obtain a high-precision voltage measurement value.

[0084] It can be further understood that this invention utilizes the accuracy of the voltage reference source to obtain the actual amplification factor of the circuit. By leveraging the temperature-dependent characteristics of the operational amplifier offset voltage and the on-board temperature detection chip, the circuit offset voltage error at different temperatures is measured and stored. During normal measurement, subtracting the circuit offset voltage error at different temperatures from the ADC measurement result yields a high-precision voltage measurement value.

[0085] In some embodiments of the present invention, the voltage measurement circuit 120 further includes:

[0086] The filter circuit is electrically connected to the output of the operational amplifier.

[0087] It is understood that the present invention discloses a high-precision voltage measurement system based on temperature detection. This system is applicable to non-precision operational amplifiers to achieve the effect of high-precision voltage measurement. It mainly utilizes the variation characteristics of operational amplifier offset voltage. By shorting the input, the circuit offset voltage value at different temperatures is obtained. Then, the normal measurement value is subtracted from the circuit offset voltage value at different temperatures to obtain a high-precision voltage measurement value.

[0088] It can be further understood that this invention utilizes the accuracy of the voltage reference source to obtain the actual amplification factor of the circuit. By leveraging the temperature-dependent characteristics of the operational amplifier offset voltage and the on-board temperature detection chip, the circuit offset voltage error at different temperatures is measured and stored. During normal measurement, subtracting the circuit offset voltage error at different temperatures from the ADC measurement result yields a high-precision voltage measurement value.

[0089] In some embodiments of the present invention, the voltage measurement circuit 120 further includes:

[0090] The amplifier circuit is electrically connected to the output terminal of the filter circuit.

[0091] It is understood that the present invention discloses a high-precision voltage measurement system based on temperature detection. This system is applicable to non-precision operational amplifiers to achieve the effect of high-precision voltage measurement. It mainly utilizes the variation characteristics of operational amplifier offset voltage. By shorting the input, the circuit offset voltage value at different temperatures is obtained. Then, the normal measurement value is subtracted from the circuit offset voltage value at different temperatures to obtain a high-precision voltage measurement value.

[0092] It can be further understood that this invention utilizes the accuracy of the voltage reference source to obtain the actual amplification factor of the circuit. By leveraging the temperature-dependent characteristics of the operational amplifier offset voltage and the on-board temperature detection chip, the circuit offset voltage error at different temperatures is measured and stored. During normal measurement, subtracting the circuit offset voltage error at different temperatures from the ADC measurement result yields a high-precision voltage measurement value.

[0093] In some embodiments of the present invention, the voltage measurement circuit 120 further includes:

[0094] The ADC is electrically connected to the output terminal of the amplifier circuit.

[0095] It is understood that the present invention discloses a high-precision voltage measurement system based on temperature detection. This system is applicable to non-precision operational amplifiers to achieve the effect of high-precision voltage measurement. It mainly utilizes the variation characteristics of operational amplifier offset voltage. By shorting the input, the circuit offset voltage value at different temperatures is obtained. Then, the normal measurement value is subtracted from the circuit offset voltage value at different temperatures to obtain a high-precision voltage measurement value.

[0096] It can be further understood that this invention utilizes the accuracy of the voltage reference source to obtain the actual amplification factor of the circuit. By leveraging the temperature-dependent characteristics of the operational amplifier offset voltage and the on-board temperature detection chip, the circuit offset voltage error at different temperatures is measured and stored. During normal measurement, subtracting the circuit offset voltage error at different temperatures from the ADC measurement result yields a high-precision voltage measurement value.

[0097] In some embodiments of the present invention, the voltage measurement circuit 120 further includes:

[0098] The digital processing chip and non-volatile memory are electrically connected to the output of the ADC.

[0099] It is understood that the present invention discloses a high-precision voltage measurement system based on temperature detection. This system is applicable to non-precision operational amplifiers to achieve the effect of high-precision voltage measurement. It mainly utilizes the variation characteristics of operational amplifier offset voltage. By shorting the input, the circuit offset voltage value at different temperatures is obtained. Then, the normal measurement value is subtracted from the circuit offset voltage value at different temperatures to obtain a high-precision voltage measurement value.

[0100] It can be further understood that this invention utilizes the accuracy of the voltage reference source to obtain the actual amplification factor of the circuit. By leveraging the temperature-dependent characteristics of the operational amplifier offset voltage and the on-board temperature detection chip, the circuit offset voltage error at different temperatures is measured and stored. During normal measurement, subtracting the circuit offset voltage error at different temperatures from the ADC measurement result yields a high-precision voltage measurement value.

[0101] Figure 3 A circuit diagram of a high-precision voltage measurement system based on temperature detection provided by the present invention under normal measurement conditions includes:

[0102] It is understood that, in one embodiment of the present invention, when switches S1 and S2 are closed and switches S3, S4, and S5 are open, the circuit operates as follows: Figure 3 As shown in the image. This state represents normal measurement.

[0103] Figure 4 A circuit diagram of the offset voltage correction state of an embodiment of the high-precision voltage measurement system based on temperature detection provided by the present invention includes:

[0104] It is understood that, in one embodiment of the present invention, switches S1, S2, S4, and S5 are all open, and S3 is closed. At this time, the positive and negative terminals of the input operational amplifier are directly connected, making the input zero. This measurement condition is for offset voltage correction, such as... Figure 4 As shown. There are: ;

[0105] in, For ADC measurement results under voltage correction measurement conditions, The temperature on the board is measured by the temperature sensing chip on the board (the temperature sensing chip on the board is located close to the operational amplifiers of the analog circuit, and the temperature of all the operational amplifiers on the board is almost the same as the temperature of the board surface). The offset voltage of the input op-amp. This is the offset voltage of the operational amplifier in the filter circuit. This refers to the offset voltage of the operational amplifier in the amplifier circuit. Nx = R2 / R1 This represents the circuit amplification factor. When there are more than three operational amplifiers in the signal processing circuit, the expression needs to be adjusted accordingly.

[0106] Figure 5 A circuit diagram of the amplification correction state of an embodiment of the high-precision voltage measurement system based on temperature detection provided by the present invention includes:

[0107] It is understood that, in one embodiment of the present invention, switches S1, S2, and S3 are open, and switches S4 and S5 are closed. At this time, the input is a fixed value Vref. This measurement condition is for amplification correction, such as... 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 (typically with an error of less than 0.05%), and the voltage deviation can be considered zero. There are: ;

[0108] in, The ADC measurement results are under measurement conditions with amplification correction. Clearly, we have: Given Vref, the circuit amplification factor can be obtained. This ensures the accurate value of the resistance, thereby eliminating the circuit amplification factor error caused by resistance error. Because the resistance value does not change with temperature, this measurement condition only needs to be measured once. It should be noted that without the amplification circuit, the circuit does not need a reference voltage source Vref and switches S4 and S5, and the amplification factor is 1.

[0109] Figure 6 A circuit diagram of an embodiment of the high-precision voltage measurement system based on temperature detection provided by the present invention, showing the offset voltage correction state at different temperatures, includes:

[0110] Understandably, the operational amplifier offset voltage will change accordingly with temperature variations, necessitating readjustment of the offset voltage and measurement. or The V1 value corresponding to each temperature is obtained and stored in the non-volatile memory of circuit 1, such as... Figure 6 As shown.

[0111] When the circuit is in normal measurement mode, we have: ;

[0112] in, From the ADC measurement, we can deduce that: When the values ​​at various temperatures are measured Then, by applying this formula, you can obtain accurate input voltage measurement results.

[0113] The high-precision voltage measurement system based on temperature detection provided by the present invention has been described in detail above. Specific examples have been used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A high-precision voltage measurement system based on temperature detection, characterized in that, include: The voltage control module is used to receive external input control commands, offset voltage and reference voltage, and control itself to open or close based on the external input control commands and transmit offset voltage and reference voltage. The voltage control module includes a first switch group, a second switch group and a third switch group; the first switch group includes a first switch S1 and a second switch S2, the second switch group includes a third switch S3, and the third switch group includes a fourth switch S4 and a fifth switch S5. The voltage measurement circuit, electrically connected to the voltage control module, is used to receive the offset voltage, reference voltage, and temperature detection results of the offset voltage, and to obtain high-precision voltage measurement results based on the offset voltage, reference voltage, and temperature detection results of the offset voltage. The temperature acquisition module is electrically connected to the voltage measurement circuit. It is used to detect the temperature of 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 reference voltage source module is electrically connected to the fourth switch S4; When S1, S2, S4, and S5 are all open, and S3 is closed, with a voltage input of 0, this measurement condition is for offset voltage correction. Therefore: ; The voltage measurement results are under offset voltage correction measurement conditions. For circuit temperature, The offset voltage of the input op-amp. This is the offset voltage of the operational amplifier in the filter circuit. This refers to the offset voltage of the operational amplifier in the amplifier circuit. Nx = R2 / R1 The amplification factor of the circuit; When switches S1, S2, and S3 are open, and switches S4 and S5 are closed, the input is a fixed value Vref, and the measurement condition is for amplification correction. Then: ; For voltage measurement results under amplification correction conditions, we have: Given Vref, the circuit amplification factor can be obtained. The accurate value; When the temperature changes, the operational amplifier offset voltage will also change accordingly. At this point, the offset voltage needs to be corrected again, and the measurement will be... or To obtain the corresponding temperature V A value of 1, when the circuit is in normal measurement condition, has: ; in, If the voltage measurement is at this time, then: When the values ​​at various temperatures are measured Then, by applying this formula, accurate input voltage measurement results can be obtained.

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

3. The high-precision voltage measurement system based on temperature detection according to claim 2, characterized in that, The voltage measurement circuit further includes: The filter circuit is electrically connected to the output of the operational amplifier.

4. The high-precision voltage measurement system based on temperature detection according to claim 3, characterized in that, The voltage measurement circuit further includes: The amplifier circuit is electrically connected to the output terminal of the filter circuit.

5. The high-precision voltage measurement system based on temperature detection according to claim 4, characterized in that, The voltage measurement circuit further includes: The ADC is electrically connected to the output terminal of the amplifier circuit.

6. The high-precision voltage measurement system based on temperature detection according to claim 5, characterized in that, The voltage measurement circuit further includes: The digital processing chip and non-volatile memory are electrically connected to the output of the ADC.

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