High-precision platinum resistor acquisition circuit and method

Abstract

The invention relates to the technical field of platinum resistor acquisition, and particularly discloses a platinum resistor high-precision acquisition circuit and method.The acquisition circuit comprises a front voltage division circuit and a rear voltage division circuit, the front voltage division circuit comprises a high-precision resistor and a platinum resistor, one end of the high-precision resistor is electrically connected with a power source, the other end of the high-precision resistor is electrically connected with one end of the platinum resistor, and the other end of the platinum resistor is electrically connected with the ground; the driving enhancement circuit is electrically connected with the front voltage division circuit; and a reference voltage input end of the sigma-delta ADC acquisition circuit is connected with the partial voltage of the high-precision resistor through the driving enhancement circuit, a signal input end of the sigma-delta ADC acquisition circuit is connected with the partial voltage of the platinum resistor through the driving enhancement circuit, and a signal output end of the sigma-delta ADC acquisition circuit serves as an output end of the acquisition circuit. The front voltage division circuit, the driving enhancement circuit and the sigma delta ADC acquisition circuit are designed, and compared with a traditional constant current source type acquisition circuit, the acquisition circuit is compact in structure, few in used devices, low in power consumption and capable of supporting platinum resistors ranging from 100 ohms to 1 k ohms, the full-scale precision can reach 0.5 DEG C, and the sampling process is stable and reliable.

Description

Technical Field

[0001] The invention relates to the technical field of platinum resistance acquisition, and in particular to a platinum resistance high-precision acquisition circuit and method. Background Art

[0002] Platinum resistance temperature sensor is a temperature sensor made by using a certain functional relationship between its resistance and temperature. Due to its advantages of high measurement accuracy, large measurement range, good reproducibility and stability, it is widely used in temperature measurement in the medium temperature range (-200℃~650℃).

[0003] According to the different design requirements of the control system, the design of the temperature monitoring system also changes. Some use integrated chips, while others use constant current source devices and constant voltage source devices. Because platinum thermal resistors have the advantages of large measurement range, good stability, high indication reproducibility and oxidation resistance, temperature measurement systems often use Pt100 platinum thermal resistors as temperature sensing elements to design and implement temperature sensors.

[0004] The traditional acquisition circuit uses a constant current measurement circuit, which has a large circuit volume, low measurement accuracy and complex temperature compensation.

[0005] Based on this technical background, the present invention studies a platinum resistance high-precision acquisition circuit and method. Summary of the invention

[0006] In view of the shortcomings of the prior art, the present invention provides a high-precision acquisition circuit and method for a platinum resistor. The acquisition circuit is designed with a pre-voltage divider circuit, a drive enhancement circuit and a ΣΔADC acquisition circuit. Compared with the traditional constant current source acquisition circuit, the acquisition circuit has a compact structure, uses fewer devices, and has low power consumption. It supports 100Ω to 1kΩ platinum resistors, and the full-scale accuracy can reach 0.5℃. It is stable and reliable during the sampling process.

[0007] In order to achieve the above object, the first aspect of the present invention provides a platinum resistance high-precision acquisition circuit, comprising:

[0008] A pre-voltage divider circuit comprises a high-precision resistor and a platinum resistor, wherein one end of the high-precision resistor is electrically connected to a power supply, and the other end of the high-precision resistor is electrically connected to one end of the platinum resistor, and the other end of the platinum resistor is electrically connected to the ground;

[0009] A driving enhancement circuit, electrically connected to the pre-voltage divider circuit, and used to enhance the driving capability of the pre-voltage divider circuit;

[0010] The ΣΔADC acquisition circuit has a reference voltage input terminal electrically connected to the voltage divider of the high-precision resistor via the drive enhancement circuit, a signal input terminal electrically connected to the voltage divider of the platinum resistor via the drive enhancement circuit, and a signal output terminal serving as the output terminal of the acquisition circuit.

[0011] The second aspect of the present invention provides a high-precision platinum resistance acquisition method performed in the above acquisition circuit, comprising:

[0012] One end of the high-precision resistor is electrically connected to the power supply, and the other end is electrically connected to one end of the platinum resistor, and the other end of the platinum resistor is electrically connected to the ground to form a pre-voltage divider circuit;

[0013] The divided voltage of the high-precision resistor is used as the reference voltage of the ΣΔADC acquisition circuit after driving enhancement;

[0014] The signal input end of the ΣΔADC acquisition circuit is used to acquire the divided voltage of the driven enhanced platinum resistor.

[0015] The beneficial effects of the present invention include:

[0016] (1) The high-precision platinum resistance acquisition circuit proposed in the present invention is designed with a pre-voltage divider circuit, a drive enhancement circuit and a ΣΔADC acquisition circuit. Compared with the traditional constant current source acquisition circuit, the acquisition circuit has a compact structure, uses fewer components, and has low power consumption. It supports 100Ω to 1kΩ platinum resistances, and the full-scale accuracy can reach 0.5°C. It is stable and reliable during the sampling process.

[0017] (2) The high-precision acquisition circuit of the platinum resistor proposed in the present invention only needs a constant voltage source to power the pre-voltage divider circuit, and does not require a precision constant current source, which is simple and easy to implement. The voltage obtained by the high-precision resistor in the voltage divider circuit is used as the reference voltage of the ΣΔADC acquisition circuit after passing through the driving enhancement circuit; the measured platinum resistor voltage is used as the acquisition signal input of the ΣΔADC acquisition circuit after passing through the driving enhancement circuit.

[0018] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings.

[0020] Figure 1 This is a schematic diagram of the structure of the platinum resistance high-precision data acquisition circuit proposed by the present invention.

[0021] Description of reference numerals:

[0022] 1-pre-voltage divider circuit, 2-drive enhancement circuit, 3-ΣΔADC acquisition circuit;

[0023] REF-reference voltage input terminal, ADC_IN-signal input terminal. DETAILED DESCRIPTION

[0024] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0025] The present invention provides a platinum resistance high-precision acquisition circuit, such as Figure 1 As shown, including:

[0026] The pre-voltage divider circuit 1 comprises a high-precision resistor and a platinum resistor, one end of the high-precision resistor is electrically connected to the power supply, the other end of the high-precision resistor is electrically connected to one end of the platinum resistor, and the other end of the platinum resistor is electrically connected to the ground;

[0027] The driving enhancement circuit 2 is electrically connected to the pre-voltage divider circuit 1 and is used to enhance the driving capability of the pre-voltage divider circuit 1;

[0028] ΣΔADC acquisition circuit 3, the reference voltage input terminal REF is electrically connected to the voltage division of the high-precision resistor through the drive enhancement circuit 2, the signal input terminal ADC_IN is electrically connected to the voltage division of the platinum resistor through the drive enhancement circuit 2, and the signal output terminal serves as the output terminal of the acquisition circuit.

[0029] In the present invention, a pre-voltage divider circuit, a drive enhancement circuit and a ΣΔADC acquisition circuit are designed. Compared with the traditional constant current source acquisition circuit, the acquisition circuit has a compact structure, uses fewer devices, has low power consumption, supports 100Ω to 1kΩ platinum resistors, and the full-scale accuracy can reach 0.5℃. It is stable and reliable during the sampling process.

[0030] According to the present invention, the accuracy of the high-precision resistor is 0.05%;

[0031] The platinum resistance is a platinum resistance of PT100Ω to PT1000 type.

[0032] According to the present invention, the acquisition circuit is compatible with 2-wire, 3-wire and 4-wire sensor connections.

[0033] According to the present invention, the acquisition circuit has an overvoltage protection function.

[0034] According to the present invention, the full-scale accuracy of the acquisition circuit is 0.5°C.

[0035] Preferably, the acquisition circuit has open circuit, short circuit and over-range fault detection functions.

[0036] According to the present invention, the reference voltage input terminal REF is a pair of differential input terminals, and the input voltage of the pair of differential input terminals is the voltage across the high-precision resistor.

[0037] According to the present invention, the signal input terminal ADC_IN is a pair of differential input terminals, and the voltage collected by the pair of differential input terminals is the voltage across the platinum resistor.

[0038] In the present invention, the pre-voltage divider circuit only needs to be powered by a constant voltage source, and does not require a precise constant current source, so it is simple and easy to implement. The voltage obtained by the high-precision resistor in the voltage divider circuit is used as the reference voltage of the ΣΔADC acquisition circuit after passing through the driving enhancement circuit; the measured platinum resistor voltage is used as the acquisition signal input of the ΣΔADC acquisition circuit after passing through the driving enhancement circuit.

[0039] The present invention also provides a platinum resistance high-precision acquisition method performed in the above acquisition circuit, comprising:

[0040] One end of the high-precision resistor is electrically connected to the power supply, the other end is electrically connected to one end of the platinum resistor, and the other end of the platinum resistor is electrically connected to the ground, so as to form a pre-voltage divider circuit 1;

[0041] The divided voltage of the high-precision resistor is used as the reference voltage of the ΣΔADC acquisition circuit 3 after being driven and enhanced;

[0042] The signal input terminal ADC_IN of the ΣΔADC acquisition circuit 3 is used to acquire the divided voltage of the driven enhanced platinum resistor.

[0043] According to the present invention, the voltage division of the high-precision resistor is used as the reference voltage of the ΣΔADC acquisition circuit 3 after being driven and enhanced, including:

[0044] The voltage across the high-precision resistor is used as a pair of differential reference voltages of the ΣΔADC acquisition circuit 3 after being driven and enhanced;

[0045] Using the signal input terminal ADC_IN of the ΣΔADC acquisition circuit 3 to collect the divided voltage of the driven enhanced platinum resistor includes:

[0046] The voltage across the driven enhanced platinum resistor is collected using a pair of differential signal input terminals ADC_IN of the ΣΔADC collection circuit 3 .

[0047] The present invention will be described in more detail below by way of examples.

[0048] Embodiment 1:

[0049] like Figure 1 As shown, this embodiment provides a platinum resistance high-precision acquisition circuit, including:

[0050] The pre-voltage divider circuit 1 comprises a high-precision resistor and a platinum resistor, one end of the high-precision resistor is electrically connected to the power supply, the other end of the high-precision resistor is electrically connected to one end of the platinum resistor, and the other end of the platinum resistor is electrically connected to the ground;

[0051] The driving enhancement circuit 2 is electrically connected to the pre-voltage divider circuit 1 and is used to enhance the driving capability of the pre-voltage divider circuit 1;

[0052] ΣΔADC acquisition circuit 3, the reference voltage input terminal REF is electrically connected to the voltage division of the high-precision resistor via the driving enhancement circuit 2, the signal input terminal ADC_IN is electrically connected to the voltage division of the platinum resistor via the driving enhancement circuit 2, and the signal output terminal serves as the output terminal of the acquisition circuit;

[0053] In this embodiment, the accuracy of the high-precision resistor is 0.05%;

[0054] The platinum resistor is a platinum resistor of PT100Ω to PT1000 type;

[0055] The acquisition circuit is compatible with 2-wire, 3-wire and 4-wire sensor connections and has overvoltage protection function;

[0056] The full-scale accuracy of the acquisition circuit is 0.5°C, and it has open circuit, short circuit and over-range fault detection functions;

[0057] In this embodiment, the reference voltage input terminal REF is a pair of differential input terminals, and the input voltage of the pair of differential input terminals is the voltage across the high-precision resistor;

[0058] The signal input terminal ADC_IN is a pair of differential input terminals, and the voltage collected by the pair of differential input terminals is the voltage across the platinum resistor;

[0059] This embodiment provides a high-precision platinum resistance acquisition method, including:

[0060] One end of the high-precision resistor is electrically connected to the power supply, the other end is electrically connected to one end of the platinum resistor, and the other end of the platinum resistor is electrically connected to the ground, so as to form a pre-voltage divider circuit 1;

[0061] The voltage across the high-precision resistor is used as a pair of differential reference voltages of the ΣΔADC acquisition circuit 3 after being driven and enhanced;

[0062] The voltage across the driven enhanced platinum resistor is collected using a pair of differential signal input terminals ADC_IN of the ΣΔADC collection circuit 3 .

[0063] The high-precision platinum resistance acquisition circuit proposed in the embodiment of the present invention designs a pre-voltage divider circuit, a drive enhancement circuit and a ΣΔADC acquisition circuit. Compared with the traditional constant current source acquisition circuit, the acquisition circuit has a compact structure, uses fewer devices, has low power consumption, supports 100Ω to 1kΩ platinum resistance, and the full-scale accuracy can reach 0.5°C. It is stable and reliable during the sampling process.

[0064] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A platinum resistance high-precision acquisition circuit, characterized in that: include: A pre-voltage divider circuit comprises a high-precision resistor and a platinum resistor, wherein one end of the high-precision resistor is electrically connected to a power supply, and the other end of the high-precision resistor is electrically connected to one end of the platinum resistor, and the other end of the platinum resistor is electrically connected to the ground; A driving enhancement circuit, electrically connected to the pre-voltage divider circuit, and used to enhance the driving capability of the pre-voltage divider circuit; The ΣΔADC acquisition circuit has a reference voltage input terminal electrically connected to the voltage divider of the high-precision resistor via the drive enhancement circuit, a signal input terminal electrically connected to the voltage divider of the platinum resistor via the drive enhancement circuit, and a signal output terminal serving as the output terminal of the acquisition circuit.

2. The acquisition circuit according to claim 1, characterized in that: The precision of the high-precision resistor is 0.05%; The platinum resistor is a platinum resistor of PT100Ω to PT1000 type.

3. The acquisition circuit according to claim 1, characterized in that: The acquisition circuit described is compatible with 2-wire, 3-wire, and 4-wire sensor connections.

4. The acquisition circuit according to claim 1, characterized in that: The acquisition circuit has an overvoltage protection function.

5. The acquisition circuit according to claim 1, characterized in that: The full-scale accuracy of the acquisition circuit is 0.5°C.

6. The acquisition circuit according to claim 1, characterized in that: The acquisition circuit has the functions of open circuit, short circuit and over-range fault detection.

7. The acquisition circuit according to claim 1, characterized in that: The reference voltage input terminal is a pair of differential input terminals, and the input voltage of the pair of differential input terminals is the voltage across the high-precision resistor.

8. The acquisition circuit according to claim 1, characterized in that: The signal input end is a pair of differential input ends, and the voltage collected by the pair of differential input ends is the voltage across the two ends of the platinum resistor.

9. A high-precision platinum resistance acquisition method performed in the acquisition circuit described in any one of claims 1 to 8, characterized in that: include: One end of the high-precision resistor is electrically connected to the power supply, and the other end is electrically connected to one end of the platinum resistor, and the other end of the platinum resistor is electrically connected to the ground to form a pre-voltage divider circuit; The divided voltage of the high-precision resistor is used as the reference voltage of the ΣΔADC acquisition circuit after driving enhancement; The signal input end of the ΣΔADC acquisition circuit is used to acquire the divided voltage of the driven enhanced platinum resistor.

10. The system according to claim 9, characterized in that The divided voltage of the high-precision resistor is used as the reference voltage of the ΣΔADC acquisition circuit after driving enhancement, including: The voltage across the high-precision resistor is used as a pair of differential reference voltages for the ΣΔADC acquisition circuit after being driven and enhanced; Using the signal input end of the ΣΔADC acquisition circuit to collect the divided voltage of the driven enhanced platinum resistor includes: A pair of differential signal input terminals of the ΣΔADC acquisition circuit are used to acquire the voltage across the driven enhanced platinum resistor.

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