A sensor output conversion circuit

Abstract

This invention discloses a sensor output conversion circuit, comprising: a conditioning chip, a voltage regulator, a path controller, and a negative feedback amplifier circuit. The negative feedback amplifier circuit includes an operational amplifier electrically connected to a first resistor, a second resistor, and a third resistor, used to convert a conditioned output signal in a first voltage range into a conditioned signal output in a second voltage range. This invention utilizes the virtual ground, near-infinite input impedance, and near-infinite common-mode rejection ratio of the operational amplifier to convert a conditioned output signal in the 0-5V range into a conditioned signal output in the 0-10V range, achieving a linear electrical connection between the sensor circuit and the industrial equipment circuit. Furthermore, by selecting components with different parameters and switching paths using the path controller, the initial signal calibration and conditioned signal output of the front-end conditioning chip can be conveniently achieved.

Description

Technical Field

[0001] This invention relates to the field of output conversion circuit technology, and more particularly to a sensor output conversion circuit. Background Technology

[0002] In various chip application systems, the 0V-10V voltage output specification has extremely high versatility and widespread applicability in industrial scenarios such as industrial sensor applications and industrial control. It is a standard output requirement that is widely followed and adopted in this field. The core considerations in formulating this voltage output specification are both practicality and scenario adaptability. On the one hand, it is to effectively improve the anti-interference performance of the circuit in the complex electromagnetic environment of industry and ensure the stability of signal transmission. On the other hand, it is to scientifically balance the actual output capability of the operational amplifier with the mainstream 24V or 12V operating voltage in the industrial field, ensuring that the circuit can stably achieve the target output under the conventional operating voltage. At the same time, the specification also fully takes into account the supporting use requirements of 4-20mA standard current output in the industrial field, realizing the coordinated adaptation of voltage output and current output, and meeting the overall signal transmission and control requirements of industrial systems.

[0003] The operating voltage and dynamic range of sensors are basically within the 0V-5V range. In actual engineering designs with 0V-10V voltage output, although existing technologies can meet the conversion requirements of this specification through various solutions such as dedicated amplifier circuits, MCU integrated circuits, or ASIC dedicated chips, the overall R&D and application costs of these technologies are relatively high, raising the application threshold of the products and making it difficult to implement and popularize them in many cost-sensitive industrial application scenarios. Moreover, the core chips used in these technologies mostly rely on products from external companies, which hinders the R&D, trial production, mass production, and market delivery of related industrial products. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by proposing a sensor output conversion circuit.

[0005] To achieve the above objectives, the present invention provides a sensor output conversion circuit, comprising: The conditioning chip is electrically connected to the front-end sensor and is used to send sensor drive signals, acquire the sensor's raw voltage signal, perform signal conditioning, and output an analog voltage signal. The voltage regulator, electrically connected to the conditioning chip, is used to convert the high voltage output from the high voltage power supply terminal into a low voltage to power the conditioning chip and the sensor. The path controller, electrically connected to the conditioning chip, is used to switch the electrical path to perform initial signal calibration and conditioning signal output for the conditioning chip; A negative feedback amplifier circuit is electrically connected to a voltage regulator and a path controller. The negative feedback amplifier circuit is equipped with an operational amplifier, which is electrically connected to a first resistor, a second resistor, and a third resistor. It is used to convert a conditioned output signal in a first voltage range into a conditioned signal output in a second voltage range.

[0006] In some embodiments, the power supply pin of the conditioning chip is electrically connected to the voltage regulator, the output pin of the conditioning chip is electrically connected to the path controller, the ground pin of the conditioning chip is electrically connected to the ground terminal, and a first capacitor is provided on the circuit connecting the ground pin and the ground terminal.

[0007] In some embodiments, the voltage regulator is electrically connected to the high-voltage power supply terminal, the two ends of the voltage regulator are grounded, and a second capacitor and a third capacitor are provided on the circuit connecting the voltage regulator and the ground terminal.

[0008] In some embodiments, the first gate of the path controller is electrically connected to the operational amplifier, and the second gate of the path controller is electrically connected to the calibration interface.

[0009] In some embodiments, the positive input pin of the operational amplifier is electrically connected to the path controller through a first resistor, the negative input pin of the operational amplifier is electrically connected to the ground terminal through a second resistor, and the negative input pin of the operational amplifier is electrically connected to the output pin of the operational amplifier through a third resistor.

[0010] In some embodiments, the positive power supply pin of the operational amplifier is electrically connected to the high-voltage power supply terminal, the negative power supply pin of the operational amplifier is electrically connected to the ground terminal, and the output pin of the operational amplifier is electrically connected to the voltage output terminal.

[0011] In some embodiments, the output voltage value of the operational amplifier The calculation formula is

[0012] in, This refers to the common-mode rejection ratio of the operational amplifier. This is the resistance value of the second resistor. This is the resistance value of the third resistor. This is the positive input voltage value of the operational amplifier.

[0013] In some embodiments, the high-voltage power supply is a 12-24V DC power supply.

[0014] In some embodiments, the first voltage range is 0-5V and the second voltage range is 0-10V.

[0015] In some embodiments, the first resistor is a fixed resistor, and the second and third resistors are variable resistors.

[0016] The present invention has the following beneficial effects: This invention provides a sensor output conversion circuit. The negative feedback amplifier circuit includes an operational amplifier, which is electrically connected to a first resistor, a second resistor, and a third resistor. By utilizing the virtual ground, near-infinite input impedance, and near-infinite common-mode rejection ratio of the operational amplifier, the conditioned output signal in the 0-5V range is converted into a conditioned signal output in the 0-10V range, achieving a linear electrical connection between the sensor circuit and the industrial equipment circuit. Furthermore, by selecting components with different parameters and switching paths using a path controller, the initial signal calibration and conditioned signal output of the front-end conditioning chip can be easily achieved. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the sensor output conversion circuit proposed in this invention.

[0018] Legend: 1. Sensor; 2. Conditioning chip; 3. Voltage regulator; 4. Path controller; 5. Operational amplifier. Detailed Implementation

[0019] 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 some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] This application provides a sensor output conversion circuit that solves the problem that the overall R&D and application costs of existing technical solutions are too high, raising the application threshold and making it difficult to implement and popularize in many cost-sensitive industrial applications. This application utilizes the electrical characteristics of an operational amplifier to convert a 0-5V conditioned output signal into a 0-10V conditioned signal output, achieving a linear electrical connection between the sensor circuit and the industrial equipment circuit.

[0021] Please refer to the following examples for details: Reference Figure 1 The present invention provides an embodiment of a sensor output conversion circuit, the specific structure of which includes: Conditioning chip 2 ( Figure 1The middle part is XPS), which is electrically connected to the front-end sensor 1. It is used to send the sensor 1 drive signal, acquire the original voltage signal of sensor 1, perform signal conditioning, and output the analog voltage signal. Voltage regulator 3 ( Figure 1 The LDO (Low Voltage Detector) is electrically connected to the conditioning chip 2 and is used to convert the high voltage output from the high voltage power supply terminal into a low voltage to power the conditioning chip 2 and the sensor 1. Path controller 4 ( Figure 1 The middle part (CTROL) is electrically connected to the conditioning chip 2 and is used to switch the electrical path to perform initial signal calibration and conditioning signal output for the conditioning chip 2; The negative feedback amplifier circuit is electrically connected to the voltage regulator 3 and the path controller 4. The negative feedback amplifier circuit is equipped with an operational amplifier 5. Figure 1 The middle one is LM321), operational amplifier 5 and the first resistor ( Figure 1 R1 is in the middle, and the second resistor is ( Figure 1 R2) and the third resistor ( Figure 1 The circuit is electrically connected to R3, which is used to convert the conditioned output signal in the first voltage range into a conditioned signal output in the second voltage range.

[0022] In some embodiments, sensor 1 (in) Figure 1 MEMS (Mechanical, Electronic and Semiconductor Systems) can directly convert environmental physical quantities such as pressure, temperature, and humidity into voltage signals. The output signal of this type of sensor is usually only a few millivolts to tens of millivolts. Not only is the amplitude weak and easily interfered with, but its response curve also shows obvious nonlinearity with changes in physical quantities and temperature fluctuations. If it is not conditioned, it will directly lead to measurement errors. Therefore, it is necessary to rely on conditioning chip 2 for compensation and correction.

[0023] In some embodiments, the power supply pin of conditioning chip 2 (in...) Figure 1 The VDD pin is electrically connected to regulator 3 to power the internal circuitry of the chip; the output pin of conditioning chip 2 (in...) Figure 1 The VDDO (Voltage Direction Detector) is electrically connected to the path controller 4, transmitting the conditioned 0-5V signal to different ports via the path controller 4; the ground pin of the conditioning chip 2 (in...) Figure 1 The VSS pin is electrically connected to the ground terminal, and a first capacitor is provided on the circuit connecting the ground pin to the ground terminal. Figure 1 The capacitor C1 in the middle can effectively filter out high-frequency noise on the power line, reduce ripple interference in the chip power supply, and ensure the stability of signal conditioning.

[0024] It should be noted that the conditioning chip 2 is manufactured by Shanghai Chippu Technology Co., Ltd., which can provide a driving power signal to the sensor 1 while performing real-time temperature compensation and nonlinear correction on the nonlinear response curve of the sensor 1, ultimately achieving a stable one-to-one correspondence between physical quantities and output voltage.

[0025] In some embodiments, the voltage regulator 3 is connected to the high-voltage power supply terminal (in... Figure 1 The voltage regulator 3 is electrically connected to DC power, and its two ends are grounded. A second capacitor is provided on the circuit connecting the voltage regulator 3 to the ground terminal. Figure 1 C2) and the third capacitor (in Figure 1 The first capacitor is C3; the second capacitor, as the output capacitor, can further filter and regulate the voltage to ensure the stability of the output voltage; the third capacitor, as the input capacitor, can suppress the ripple of the input power supply.

[0026] It should be noted that the voltage regulator 3 is a low dropout regulator (LDO) that converts the 12-24V power supply voltage commonly used in the industrial field into a 5V power supply voltage to supply the conditioning chip 2 and the front-end sensor 1.

[0027] Industrial DC power supplies typically employ a wide voltage range of 12-24V. This voltage level not only adapts to the power supply standards of various industrial equipment but also provides strong anti-interference capabilities and redundancy. In some embodiments, the high-voltage power supply is a 12-24V DC power supply, which is converted to 5V by a voltage regulator 3. This eliminates the need for an additional dedicated power supply module, effectively reducing the system's hardware cost and integration complexity.

[0028] In some embodiments, the first gate of the path controller 4 (in) Figure 1 The second gate of the path controller 4 (QS1) is electrically connected to the operational amplifier 5. Figure 1 The middle part is QS2) and the calibration interface (in Figure 1 The middle part is the DIO (electrical connection).

[0029] It should be explained in detail that the path controller 4 is used to switch the electrical path to perform initial signal calibration and conditioned signal output for the conditioning chip 2; when connected to the calibration interface, the measurement system composed of the conditioning chip 2 and the sensor 1 can be initially calibrated through the calibration interface; when connected to the negative feedback amplifier circuit, the 0-5V output signal of the sensor 1 can be converted into an industrial-grade 0V-10V output signal.

[0030] In some embodiments, the positive input pin of operational amplifier 5 (in...) Figure 1The +IN pin of the operational amplifier 5 is electrically connected to the path controller 4 via a first resistor. This first resistor serves as a current limiter and impedance matching resistor, optimizing signal transmission and reducing losses. Figure 1 The negative input pin of the operational amplifier 5 is electrically connected to the ground terminal through the second resistor, and the negative input pin of the operational amplifier 5 is electrically connected to the output pin of the operational amplifier 5 through the third resistor. The second and third resistors serve as negative feedback resistors, which can determine the specific amplification factor. The theoretical amplification factor of the amplifier in this application is about 2.27 times, and the amplification factor is close to 2 times based on the actual characteristics.

[0031] In some embodiments, the positive power supply pin of operational amplifier 5 (in...) Figure 1 The VCC pin (in the middle) is electrically connected to the high-voltage power supply terminal, and the negative power supply pin of operational amplifier 5 (in the middle) is electrically connected to the high-voltage power supply terminal. Figure 1 The VEE pin in the middle is electrically connected to the ground terminal, and the output pin of operational amplifier 5 (in...) Figure 1 (OUT) and voltage output terminal (in Figure 1 The middle part is VOUT) for electrical connection.

[0032] In some embodiments, the first voltage range is 0-5V and the second voltage range is 0-10V.

[0033] It should be explained in detail that this negative feedback amplifier circuit can convert a conditioned output signal from 0-5V to a conditioned output signal from 0-10V. The second and third resistors serve as feedback resistors. Combined with the characteristics of operational amplifier 5, the formula for calculating the output voltage Vout of operational amplifier 5 is as follows:

[0034] in, This refers to the common-mode rejection ratio of operational amplifier 5. This is the resistance value of the second resistor. This is the resistance value of the third resistor. This is the positive input voltage value of operational amplifier 5.

[0035] Furthermore, the common-mode rejection ratio of an ideal operational amplifier 5 should be infinite, but the common-mode rejection ratio of an actual operational amplifier 5 has a finite value; the operational amplifier 5 in this application is model LM321, and its corresponding common-mode rejection ratio is approximately 90 dB. Therefore, the actual output voltage value of operational amplifier 5 in this application is ultimately...

[0036]

[0037] In addition, to eliminate rail high-voltage ripple and GND noise interference, the output of conditioning chip 2 is limited to 20mV-4400mV. Therefore, the output voltage after this conversion circuit in this application is [value missing]. ,

[0038] in, This is an extremely low output voltage value. This represents the extremely high output voltage value.

[0039] In some embodiments, the first resistor is a fixed resistor, while the second and third resistors can be replaced with precision variable resistors such as potentiometers or digital potentiometers. By adjusting the resistance value of the variable resistor, the deviation of the amplification factor can be corrected in real time, and the errors caused by factors such as component tolerance and temperature drift can be offset, ensuring the accuracy of the output voltage. This is suitable for calibration in mass production and precision adjustment after changes in the field environment.

[0040] Through the above technical solution, this application achieves efficient signal conversion of sensor 1 through simple hardware design and reasonable component matching: the negative feedback amplifier circuit utilizes the high input impedance and high common-mode rejection ratio of operational amplifier 5 to linearly amplify the 0-5V signal to 0-10V, completing the electrical connection between sensor 1 and industrial equipment; the path controller 4 supports rapid switching between system calibration and signal output, and adopts conditioning chip 2 and general components, effectively improving the reliability and maintainability of the system.

[0041] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A sensor output conversion circuit, characterized in that, include: The conditioning chip is electrically connected to the front-end sensor and is used to send sensor drive signals, acquire the sensor's raw voltage signal, perform signal conditioning, and output an analog voltage signal. The voltage regulator, electrically connected to the conditioning chip, is used to convert the high voltage output from the high voltage power supply terminal into a low voltage to power the conditioning chip and the sensor. The path controller, electrically connected to the conditioning chip, is used to switch the electrical path to perform initial signal calibration and conditioning signal output for the conditioning chip; A negative feedback amplifier circuit is electrically connected to a voltage regulator and a path controller. The negative feedback amplifier circuit is equipped with an operational amplifier, which is electrically connected to a first resistor, a second resistor, and a third resistor. It is used to convert a conditioned output signal in a first voltage range into a conditioned signal output in a second voltage range.

2. The sensor output conversion circuit according to claim 1, characterized in that, The power supply pin of the conditioning chip is electrically connected to the voltage regulator, the output pin of the conditioning chip is electrically connected to the path controller, the ground pin of the conditioning chip is electrically connected to the ground terminal, and a first capacitor is provided on the circuit connecting the ground pin and the ground terminal.

3. The sensor output conversion circuit according to claim 1, characterized in that, The voltage regulator is electrically connected to the high-voltage power supply terminal, and both ends of the voltage regulator are grounded. A second capacitor and a third capacitor are provided on the circuit connecting the voltage regulator and the ground terminal.

4. The sensor output conversion circuit according to claim 1, characterized in that, The first gate of the path controller is electrically connected to the operational amplifier, and the second gate of the path controller is electrically connected to the calibration interface.

5. The sensor output conversion circuit according to claim 1, characterized in that, The positive input pin of the operational amplifier is electrically connected to the path controller through a first resistor, the negative input pin of the operational amplifier is electrically connected to the ground terminal through a second resistor, and the negative input pin of the operational amplifier is electrically connected to the output pin of the operational amplifier through a third resistor.

6. The sensor output conversion circuit according to claim 5, characterized in that, The positive power supply pin of the operational amplifier is electrically connected to the high-voltage power supply terminal, the negative power supply pin of the operational amplifier is electrically connected to the ground terminal, and the output pin of the operational amplifier is electrically connected to the voltage output terminal.

7. The sensor output conversion circuit according to claim 5, characterized in that, The output voltage value of the operational amplifier The calculation formula is: in, This refers to the common-mode rejection ratio of the operational amplifier. This is the resistance value of the second resistor. This is the resistance value of the third resistor. This is the positive input voltage value of the operational amplifier.

8. The sensor output conversion circuit according to claim 1, characterized in that, The high-voltage power supply terminal is a 12-24V DC power supply.

9. The sensor output conversion circuit according to claim 1, characterized in that, The first voltage range is 0-5V, and the second voltage range is 0-10V.

10. The sensor output conversion circuit according to claim 1, characterized in that, The first resistor is a fixed resistor, while the second and third resistors are variable resistors.

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