Sensor signal amplification processing system

Abstract

The utility model relates to an electrochemical oxygen sensor, in particular to a sensor signal amplification processing system. The system comprises a power supply unit, a first-stage amplification unit, a second-stage amplification unit and a negative pressure unit, the input side of the first-stage amplification unit is connected with the output end of a sensor, and the output end of the first-stage amplification unit is connected with the input end of the second-stage amplification unit; the output end of the secondary amplification unit is used as the output end of the sensor signal amplification processing system; the first-stage amplification unit and the second-stage amplification unit are respectively connected with a negative pressure unit and a power supply unit; and the power supply unit is connected with the negative pressure unit. The amplitude of the output signal of the sensor is effectively improved, so that the output signal is easily and reliably captured and processed by a subsequent data acquisition system, meanwhile, the distortion minimization in the signal amplification process is ensured, and the original accuracy and integrity of data are kept.

Description

Technical Field

[0001] The utility model relates to an electrochemical oxygen sensor, in particular to a sensor signal amplification processing system. Background Art

[0002] In the current industrial and environmental monitoring field, oxygen sensors are key detection components, and their performance directly affects the accuracy and reliability of the system's gas composition analysis. There are two major types of oxygen sensors widely used in the market: paramagnetic oxygen sensors and electrochemical oxygen sensors, each with its own significant characteristics and limitations.

[0003] Among them, paramagnetic oxygen sensors work based on the paramagnetic principle of oxygen and have advantages such as fast response speed and good long-term stability. However, these advantages are accompanied by high manufacturing costs. Especially for those application scenarios that require large-scale deployment of oxygen monitoring points, the price of paramagnetic oxygen sensors has become the main bottleneck restricting their widespread application. The high cost is directly passed on to the product terminal, increasing production costs and limiting its popularity and application in cost-sensitive industries.

[0004] In contrast, electrochemical oxygen sensors are favored for their lower cost, better selectivity and longer service life. This type of sensor determines the oxygen concentration by measuring the current generated by the electrochemical reaction and is suitable for continuous monitoring of oxygen levels. However, it cannot be ignored that a significant disadvantage of electrochemical sensors is that their output signal intensity is relatively low, which poses a challenge in practical applications. The low signal level requires an extremely sensitive and precise signal acquisition system, otherwise it is easy to cause instability and reduced accuracy of data acquisition, especially in remote monitoring or in industrial environments with noise interference. This problem is particularly prominent. In view of the above situation, it is particularly urgent to develop a signal amplification module specifically for electrochemical oxygen sensors. Summary of the invention

[0005] The utility model aims at the defects in the prior art and provides a sensor signal amplification processing system.

[0006] To achieve the above-mentioned purpose, the utility model adopts the following technical scheme, including a power supply unit, a first-level amplification unit, a second-level amplification unit and a negative pressure unit, characterized in that the input side of the first-level amplification unit is connected to the output end of the sensor, the output end of the first-level amplification unit is connected to the input end of the second-level amplification unit, and the output end of the second-level amplification unit serves as the output end of the sensor signal amplification processing system; the first-level amplification unit and the second-level amplification unit are also respectively connected to the negative pressure unit and the power supply unit; the power supply unit is connected to the negative pressure unit.

[0007] Furthermore, the first-stage amplification unit includes an instrument amplifier AD620, a gain shifter RP2, and a zero adjustment shifter RP1. The gain shifter RP2 is used for gain adjustment and is connected between the 1st and 8th pins of AD620; the positive and negative poles of the sensor input signal are respectively connected to the instrument amplifier AD620 through their own low-pass filter circuits; the zero adjustment shifter RP1 is connected to the positive pole of the sensor input signal as an input voltage bias potentiometer for adjusting the zero point; the 7th pin of AD620 is the positive power input connected to the output of the power supply unit, and the 4th pin is the negative power input connected to the output of the negative pressure unit; the 6th pin of AD620 is the output end connected to the second-stage amplification unit.

[0008] Furthermore, the positive electrode of the sensor input signal is connected to the second pin of AD620 through resistor R25, and the common connection end of resistor R25 and the second pin of AD620 is grounded through capacitor C20; the negative electrode of the sensor input signal is connected to the third pin of AD620 through resistor R24, and the common connection end of resistor R24 ​​and the fourth pin of AD620 is grounded through capacitor C19.

[0009] Furthermore, the secondary amplification unit includes a low offset operational amplifier OP07, wherein pin 2 of the low offset operational amplifier OP07 serves as an input pin and is connected to the output of the primary amplification unit through a resistor R1; pin 3 of the low offset operational amplifier OP07 is grounded through a resistor R2; pin 4 of the low offset operational amplifier OP07 is connected to the output of the negative pressure unit; pin 6 of the low offset operational amplifier OP07 serves as an output end of the sensor signal amplification and processing system; and pin 7 of the low offset operational amplifier OP07 is connected to the output end of the power supply unit.

[0010] Furthermore, the power supply unit includes a DC-DC buck chip LM2596S-5.0, wherein pin 1 of the DC-DC buck chip LM2596S-5.0 is connected to +24V as an input voltage pin, and pin 6 of the DC-DC buck chip LM2596S-5.0 is grounded; and a filter capacitor C9 and a decoupling capacitor C8 are connected between pin 1 and pin 6 of the DC-DC buck chip LM2596S-5.0, and the filter capacitor C9 and the decoupling capacitor C8 are connected in parallel; pins 3 and 5 of the DC-DC buck chip LM2596S-5.0 are both grounded; and the DC-DC buck chip Pin 2 of LM2596S-5.0 is connected to the first end of the power inductor L1, and the second end of the power inductor L1 is connected to the first-stage amplification unit, the second-stage amplification unit, and the negative voltage unit as the output voltage VDD; Pin 4 of the DC-DC step-down chip LM2596S-5.0 is connected to the second end of the power inductor L1, and the first end of the power inductor L1 is connected to the first end of the power inductor L1 through a Zener diode 1N5824 and a decoupling capacitor C4, and the common connection end of the Zener diode 1N5824 and the decoupling capacitor C4 is grounded; an output filter capacitor C13 is connected in parallel at both ends of the decoupling capacitor C4.

[0011] Furthermore, the negative pressure unit includes a charge pump ICL7660, wherein the 8th pin of the charge pump ICL7660 is connected to the power supply unit as a power input terminal, and the 5th pin of the charge pump ICL7660 is connected to the first-stage amplification unit and the second-stage amplification unit as an output pin; the 3rd and 6th pins of the charge pump ICL7660 are grounded respectively, an electrolytic capacitor C16 is connected between the 2nd and 4th pins of the charge pump ICL7660, capacitor C5 is used as an output filter capacitor, and capacitor C6 is used as a decoupling capacitor, both of which are connected to the 5th pin of the charge pump ICL7660; capacitor C7 is used as a decoupling capacitor and is connected to the 8th pin of the charge pump ICL7660.

[0012] Furthermore, the positive end of the electrolytic capacitor C16 is connected to pin 2 of the charge pump ICL7660, and the negative end of the electrolytic capacitor C16 is connected to pin 4 of the charge pump ICL7660.

[0013] Compared with the prior art, the utility model has beneficial effects.

[0014] The utility model effectively improves the amplitude of the sensor output signal, making it easy to be reliably captured and processed by the subsequent data acquisition system, while ensuring that the distortion in the signal amplification process is minimized and the original accuracy and integrity of the data are maintained.

[0015] The utility model has high hardware integration and good reliability, and can be widely used in amplifying the signals of sensors such as various electrochemical sensors and photocells, and is convenient for collection. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The utility model is further described below in conjunction with the accompanying drawings and specific implementation methods. The protection scope of the utility model is not limited to the following descriptions.

[0017] Figure 1 It is the principle block diagram of the sensor signal amplification and processing system.

[0018] Figure 2 It is a circuit diagram of a first-level amplification unit in a specific embodiment.

[0019] Figure 3 It is a circuit diagram of a secondary amplification unit in a specific embodiment.

[0020] Figure 4 is a circuit diagram of a power supply unit in a specific embodiment.

[0021] Figure 5 It is a circuit diagram of a negative pressure unit in a specific embodiment. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical scheme and beneficial effects of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, rather than all of the embodiments.

[0023] like Figure 1-5 As shown, the sensor signal amplification processing system includes a power supply unit, a primary amplification unit, a secondary amplification unit and a negative pressure unit. The input side of the primary amplification unit is connected to the output end of the sensor, the output end of the primary amplification unit is connected to the input end of the secondary amplification unit, and the output end of the secondary amplification unit is used as the output end of the sensor signal amplification processing system; the primary amplification unit and the secondary amplification unit are also connected to the negative pressure unit and the power supply unit respectively; the power supply unit is connected to the negative pressure unit. The negative pressure unit is used to provide a negative voltage for the operational amplifier powered by a dual power supply.

[0024] Among them, the first-stage amplifier unit is directly connected to the output end of the sensor and is used to amplify the weak original signal generated by the sensor for the first time. Since the output signal of the sensor is often very weak, the function of the first-stage amplifier unit is to significantly increase the signal amplitude and preliminarily improve the signal-to-noise ratio, making the signal easier to be processed by subsequent circuits. In addition, the design of this first-stage amplifier unit takes into account high input impedance to avoid load effects on the sensor.

[0025] Secondary amplifier unit: receives the signal after primary amplification and further amplifies it. It aims to achieve the required final signal level, and achieves a large gain through two-stage amplification, while reducing noise introduction and distortion through the secondary amplification design.

[0026] The power supply unit not only provides positive voltage for the amplifier unit, but also ensures the supply of negative voltage by connecting with the negative voltage unit. The primary amplifier unit and the secondary amplifier unit work in series, and the output of the former is directly fed into the input of the latter, forming a signal gain link. At the same time, both the primary amplifier unit and the secondary amplifier unit are connected to the power supply unit and the negative voltage unit, ensuring the stable supply of energy for the entire amplifier system and the necessary voltage bias conditions.

[0027] Preferably, the first-stage amplification unit includes an instrumentation amplifier AD620, a gain shifter RP2, and a zeroing shifter RP1. The gain shifter RP2 is used as a gain adjustment and is connected between the 1st and 8th pins of AD620. The positive and negative poles of the sensor input signal are respectively connected to the instrumentation amplifier AD620 through their respective low-pass filter circuits. The zeroing shifter RP1 is connected to the positive pole of the sensor input signal as an input voltage bias potentiometer for adjusting the zero point. The 7th pin of AD620 is a positive power input connected to the output of the power supply unit, and the 4th pin is a negative power input connected to the output of the negative pressure unit. The 6th pin of AD620 is an output end connected to the second-stage amplification unit. The positive pole of the sensor input signal is connected to the 2nd pin of AD620 through a resistor R25, and the common connection end of the resistor R25 and the 2nd pin of AD620 is grounded through a capacitor C20. The negative pole of the sensor input signal is connected to the 3rd pin of AD620 through a resistor R24, and the common connection end of the resistor R24 ​​and the 4th pin of AD620 is grounded through a capacitor C19.

[0028] Specifically, the first-stage amplification unit includes the instrument amplifier AD620, RP2 is connected to the 1st and 8th pins of AD620 as a gain adjustment, the positive and negative poles of the sensor input signal are respectively connected in series with a 10K resistor and in parallel with a 1UF capacitor to form a low-pass filter circuit with a cut-off frequency of 15.9Hz, RP1 is connected to the positive pole of the input voltage as an input voltage bias potentiometer to adjust the zero point, the 7th pin of AD620 is the positive power input connected to the output of the power supply unit, the 4th pin is the negative power input connected to the output of the negative pressure unit, C22 and C27 are decoupling capacitors, the 6th pin of AD620 is the output pin, C1 is a decoupling capacitor, and the first-stage amplification is completed. Among them, the gain positioner RP2, the zero positioner RP1, and the potentiometer are selected as 10K, the AD620 amplification factor is changed by adjusting RP2, and the input zero point is adjusted by adjusting RP1.

[0029] Preferably, the secondary amplification unit includes a low-offset operational amplifier OP07, wherein pin 2 of the low-offset operational amplifier OP07 serves as an input pin and is connected to the output of the primary amplification unit through a resistor R1; pin 3 of the low-offset operational amplifier OP07 is grounded through a resistor R2; pin 4 of the low-offset operational amplifier OP07 is connected to the output of the negative pressure unit; pin 6 of the low-offset operational amplifier OP07 serves as the output end of the sensor signal amplification and processing system; and pin 7 of the low-offset operational amplifier OP07 is connected to the output end of the power supply unit.

[0030] Specifically: the secondary amplification unit includes a low offset operational amplifier OP07, the second pin of OP07 is the input pin, R1 and R3 use 1K and 10K resistors respectively, the fixed amplification factor is 10 times, the seventh pin is the positive power input connected to the power supply unit output, the fourth pin is the negative power input connected to the negative voltage unit output, C2 and C3 are decoupling capacitors, the third pin is a 100K pull-down resistor, and the sixth pin outputs the final amplified signal, and the secondary amplification is completed.

[0031] Preferably, the power supply unit has a supply voltage of 24V, and the power supply unit includes a DC-DC buck chip LM2596S-5.0, wherein pin 1 of the DC-DC buck chip LM2596S-5.0 is connected to +24V as an input voltage pin, and pin 6 of the DC-DC buck chip LM2596S-5.0 is grounded; and a filter capacitor C9 and a decoupling capacitor C8 are connected between pin 1 and pin 6 of the DC-DC buck chip LM2596S-5.0, and the filter capacitor C9 and the decoupling capacitor C8 are connected in parallel; pins 3 and 5 of the DC-DC buck chip LM2596S-5.0 are both grounded; Pin 2 of the C step-down chip LM2596S-5.0 is connected to the first end of the power inductor L1, and the second end of the power inductor L1 is connected to the first-stage amplification unit, the second-stage amplification unit, and the negative voltage unit as the output voltage VDD; Pin 4 of the DC-DC step-down chip LM2596S-5.0 is connected to the second end of the power inductor L1, and the first end of the power inductor L1 is connected to the first end of the power inductor L1 through the Zener diode 1N5824 and the decoupling capacitor C4, and the common connection end of the Zener diode 1N5824 and the decoupling capacitor C4 is grounded; an output filter capacitor C13 is connected in parallel at both ends of the decoupling capacitor C4.

[0032] Preferably, the negative pressure unit includes a charge pump ICL7660, wherein the 8th pin of the charge pump ICL7660 is connected to the power supply unit as a power input terminal, and the 5th pin of the charge pump ICL7660 is connected to the first-stage amplification unit and the second-stage amplification unit as an output pin to output a reverse voltage; the 3rd and 6th pins of the charge pump ICL7660 are grounded respectively, and an electrolytic capacitor C16 is connected between the 2nd and 4th pins of the charge pump ICL7660, and the capacitor C5 is used as an output filter capacitor and the capacitor C6 is used as a decoupling capacitor, both of which are connected to the 5th pin of the charge pump ICL7660; the capacitor C7 is used as a decoupling capacitor and is connected to the 8th pin of the charge pump ICL7660. The positive end of the electrolytic capacitor C16 is connected to the 2nd pin of the charge pump ICL7660, and the negative end of the electrolytic capacitor C16 is connected to the 4th pin of the charge pump ICL7660.

[0033] Specifically, the negative pressure unit includes a charge pump ICL7660, the 8th pin of ICL7660 is connected to the power supply unit as the power input terminal, the 5th pin is used as the output pin to output the reverse voltage, the 3rd and 6th pins are connected to GND, the 2nd and 4th pins are connected to the positive and negative poles of C16, C5 is the output filter capacitor, and C6 and C7 are decoupling capacitors.

[0034] The utility model adopts the AD620 chip with high precision, low offset voltage and low offset drift characteristics. The existing ordinary operational amplifier has an offset voltage of 3-7mV. If the offset voltage is too large, weak signals will be drowned by noise. The AD620 chip has the characteristics of low noise, low input bias current and low power consumption, and is low in cost, and better realizes the role of signal amplifier. In addition, the utility model also adopts a potentiometer to replace the existing resistor components, so as to achieve the effect of adjustable amplification factor of the signal amplifier.

[0035] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features thereof may be replaced by equivalents. Therefore, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope defined by the claims of the present invention.

Claims

1. A sensor signal amplification processing system, comprising a power supply unit, a primary amplification unit, a secondary amplification unit and a negative pressure unit, characterized in that: The input side of the first-stage amplification unit is connected to the output end of the sensor, the output end of the first-stage amplification unit is connected to the input end of the second-stage amplification unit, and the output end of the second-stage amplification unit serves as the output end of the sensor signal amplification processing system; The primary amplification unit and the secondary amplification unit are also connected to the negative pressure unit and the power supply unit respectively; The power supply unit is connected to the negative pressure unit.

2. A sensor signal amplification processing system according to claim 1, characterized in that: The first-stage amplification unit includes an instrument amplifier AD620, a gain shifter RP2, and a zero adjustment shifter RP1. The gain shifter RP2 is used for gain adjustment and is connected between the 1st and 8th pins of AD620; the positive and negative poles of the sensor input signal are respectively connected to the instrument amplifier AD620 through their own low-pass filter circuits; the zero adjustment shifter RP1 is connected to the positive pole of the sensor input signal as an input voltage bias potentiometer for adjusting the zero point; the 7th pin of AD620 is the positive power input connected to the output of the power supply unit, and the 4th pin is the negative power input connected to the output of the negative pressure unit; the 6th pin of AD620 is the output end connected to the second-stage amplification unit.

3. A sensor signal amplification processing system according to claim 2, characterized in that: The positive electrode of the sensor input signal is connected to the 2nd pin of AD620 through resistor R25, and the common connection end of resistor R25 and the 2nd pin of AD620 is grounded through capacitor C20; the negative electrode of the sensor input signal is connected to the 3rd pin of AD620 through resistor R24, and the common connection end of resistor R24 ​​and the 4th pin of AD620 is grounded through capacitor C19.

4. The sensor signal amplification processing system according to claim 1, characterized in that: The secondary amplification unit includes a low-offset operational amplifier OP07, wherein the 2nd pin of the low-offset operational amplifier OP07 is used as an input pin and is connected to the output of the primary amplification unit through a resistor R1; the 3rd pin of the low-offset operational amplifier OP07 is grounded through a resistor R2; the 4th pin of the low-offset operational amplifier OP07 is connected to the output of the negative pressure unit; the 6th pin of the low-offset operational amplifier OP07 is used as the output end of the sensor signal amplification processing system; and the 7th pin of the low-offset operational amplifier OP07 is connected to the output end of the power supply unit.

5. The sensor signal amplification processing system according to claim 1, characterized in that: The power supply unit includes a DC-DC buck chip LM2596S-5.0, wherein pin 1 of the DC-DC buck chip LM2596S-5.0 is connected to +24V as an input voltage pin, and pin 6 of the DC-DC buck chip LM2596S-5.0 is grounded; A filter capacitor C9 and a decoupling capacitor C8 are connected between pin 1 and pin 6 of the DC-DC step-down chip LM2596S-5.0, and the filter capacitor C9 and the decoupling capacitor C8 are connected in parallel; The 3rd and 5th pins of the DC-DC step-down chip LM2596S-5.0 are both grounded; The 2nd foot of the DC-DC step-down chip LM2596S-5.0 is connected to the first end of the power inductor L1, and the second end of the power inductor L1 is connected to the first-stage amplification unit, the second-stage amplification unit, and the negative voltage unit as the output voltage VDD; Pin 4 of the DC-DC step-down chip LM2596S-5.0 is connected to the second end of the power inductor L1. The first end of the power inductor L1 is connected to the first end of the power inductor L1 through a Zener diode 1N5824 and a decoupling capacitor C4, and the common connection end of the Zener diode 1N5824 and the decoupling capacitor C4 is grounded; an output filter capacitor C13 is connected in parallel at both ends of the decoupling capacitor C4.

6. A sensor signal amplification processing system according to claim 1, characterized in that: The negative pressure unit includes a charge pump ICL7660, wherein the 8th pin of the charge pump ICL7660 is connected to the power supply unit as a power input terminal, and the 5th pin of the charge pump ICL7660 is connected to the first-stage amplification unit and the second-stage amplification unit as an output pin to output a reverse voltage; the 3rd and 6th pins of the charge pump ICL7660 are grounded respectively, an electrolytic capacitor C16 is connected between the 2nd and 4th pins of the charge pump ICL7660, a capacitor C5 is used as an output filter capacitor, and a capacitor C6 is used as a decoupling capacitor, both of which are connected to the 5th pin of the charge pump ICL7660; a capacitor C7 is used as a decoupling capacitor and is connected to the 8th pin of the charge pump ICL7660.

7. A sensor signal amplification processing system according to claim 6, characterized in that: The positive end of the electrolytic capacitor C16 is connected to pin 2 of the charge pump ICL7660, and the negative end of the electrolytic capacitor C16 is connected to pin 4 of the charge pump ICL7660.

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