Vacuum Degree Detection Circuit, Vacuum Gauge and Vacuum Degree Detection Method

Abstract

The embodiment of the present invention provides a vacuum detection circuit, a vacuum gauge, and a vacuum detection method, belonging to the field of vacuum measurement technology. The vacuum detection circuit includes: a carrier generation module, a capacitance detection module, and an output processing module connected in sequence. The vacuum detection circuit provided by the embodiment of the present invention is provided with a carrier generation module, a capacitance detection module, and an output processing module connected in sequence. A capacitance bridge including an inner ring capacitance of a thin film capacitor is provided in the capacitance detection module. The carrier is used as the voltage input end of the capacitance bridge. A square wave with the same frequency as the carrier is used to control the switching circuit, and the switching circuit is connected to the two midpoint voltage signals of the capacitance bridge when the square wave changes direction. The output processing module processes the signal output by the switching circuit to obtain a DC voltage signal reflecting the vacuum degree. The circuit adopts an analog circuit design, which greatly reduces system noise and reduces system cost.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of vacuum measurement technology, and particularly to a vacuum degree detection circuit, a vacuum gauge, and a vacuum degree detection method. Background Art

[0002] Vacuum measurement technology is widely used in fields such as semiconductor manufacturing, chemical industry, metallurgy, and aerospace. With the continuous advancement of science and technology, the demand for vacuum instrumentation in these fields is also increasing. Vacuum measurement solutions based on different principles are also emerging, such as compression vacuum testing, hot cathode ionization vacuum testing, and Pirani thermal resistance vacuum testing. Different detection solutions are suitable for different vacuum measurement ranges. Convection vacuum testing, mercury column vacuum testing, resistance vacuum testing, and thermocouple vacuum testing are suitable for low and medium vacuum ranges, while ionization vacuum testing, hot cathode magnetron vacuum testing, and thin film capacitor vacuum testing solutions are suitable for medium and high vacuum ranges.

[0003] Figure 1 This is a schematic diagram of the structure of an existing digital-based capacitive thin-film vacuum gauge detection circuit. This solution uses a digital control scheme. The ARM controller generates a carrier wave through a digital-to-analog conversion module, and the analog signal output by the operational amplifier in the capacitance detection section also needs to be acquired through an analog-to-digital conversion module. This solution has two main drawbacks: 1) The carrier wave generated by the ARM controller through the digital-to-analog conversion module is stepped, resulting in high noise in the test results. Furthermore, high-frequency noise from digital devices can also interfere with the test results, resulting in high noise levels. 2) Due to the need for both a digital-to-analog conversion module and an analog-to-digital conversion module, this solution is costly. Summary of the Invention

[0004] In view of the defects in the prior art, embodiments of the present invention provide a vacuum detection circuit, a vacuum gauge and a vacuum detection method.

[0005] An embodiment of the present invention provides a vacuum degree detection circuit, comprising a carrier generation module, a capacitance detection module and an output processing module connected in sequence; wherein: the capacitance detection module comprises a switching circuit, a square wave signal generating circuit and a capacitance bridge composed of a first capacitor, a second capacitor, a reference capacitor and an inner ring capacitor of a film capacitor, the capacitance value of the first capacitor and the second capacitor is the same, the capacitance value of the reference capacitor and the inner ring capacitor in a vacuum state is the same; the common point of the first capacitor and the inner ring capacitor is connected to the first signal input terminal of the switching circuit, the common point of the second capacitor and the reference capacitor is connected to the second signal input terminal of the switching circuit; the common point of the first capacitor and the second capacitor is connected to the carrier output terminal of the carrier generation module, the reference capacitor is connected to the carrier output terminal of the carrier generation module, and the reference capacitor is connected to the carrier output terminal of the carrier generation module. The common point of the reference capacitor and the inner loop capacitor is grounded; or, the common point of the first capacitor and the second capacitor is grounded, and the common point of the reference capacitor and the inner loop capacitor is connected to the carrier output end of the carrier generating module; the signal output end of the square wave signal generating circuit is connected to the switch enable port of the switching circuit, and the square wave signal generating circuit outputs a square wave signal with the same frequency as the carrier output by the carrier generating module. When the square wave signal changes direction, the signal output end of the switching circuit switches between being connected to the first signal input end and being connected to the second signal input end; the signal output end of the switching circuit is connected to the input end of the output processing module, and the output processing module obtains a DC voltage signal reflecting the vacuum degree by processing the received signal.

[0006] According to a vacuum degree detection circuit provided by an embodiment of the present invention, the first capacitor, the second capacitor, the reference capacitor, and the inner ring capacitor of the thin film capacitor have the same capacitance value in a vacuum state.

[0007] According to a vacuum degree detection circuit provided by an embodiment of the present invention, the square wave signal generating circuit includes a comparator; wherein the carrier output end of the carrier generating module is connected to the positive input end of the comparator, and the negative input end of the comparator is grounded; or, the carrier output end of the carrier generating module is connected to the negative input end of the comparator, and the positive input end of the comparator is grounded.

[0008] According to a vacuum degree detection circuit provided by an embodiment of the present invention, the reference capacitor is an outer ring capacitor of the thin film capacitor.

[0009] According to an embodiment of the present invention, a vacuum detection circuit is provided, which further includes a first negative feedback module; wherein the input end of the first negative feedback module is connected to the carrier output end of the carrier generation module, and the output end of the first negative feedback module is connected to the signal input end of the carrier generation module.

[0010] According to a vacuum degree detection circuit provided by an embodiment of the present invention, the first negative feedback module includes a first low-pass filter, a first proportional operation circuit and a PI adjustment module connected in sequence; wherein the input end of the first low-pass filter is connected to the carrier output end of the carrier generation module, and the output end of the PI adjustment module is connected to the signal input end of the carrier generation module.

[0011] According to an embodiment of the present invention, a vacuum detection circuit is provided, which further includes a second negative feedback module; wherein the input end of the second negative feedback module is connected to the signal output end of the switching circuit, and the output end of the second negative feedback module is connected to the signal input end of the carrier generation module.

[0012] According to a vacuum degree detection circuit provided by an embodiment of the present invention, the second negative feedback module includes a second low-pass filter, a second proportional operation circuit and the PI adjustment module connected in sequence; wherein the input end of the second low-pass filter is connected to the signal output end of the switching circuit.

[0013] An embodiment of the present invention further provides a vacuum gauge, comprising any one of the above vacuum degree detection circuits.

[0014] An embodiment of the present invention also provides a vacuum detection method based on any of the above-mentioned vacuum detection circuits, including: obtaining the output voltage of the output processing module and the calibration data of the test air pressure based on different test air pressures; obtaining the current measured air pressure value according to the calibration data and the voltage signal output by the output processing module during actual measurement.

[0015] An embodiment of the present invention further provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the steps of any of the above-described vacuum degree detection methods are implemented.

[0016] An embodiment of the present invention further provides a non-transitory computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the steps of any of the above-mentioned vacuum degree detection methods are implemented.

[0017] An embodiment of the present invention further provides a computer program product, comprising a computer program, wherein when the computer program is executed by a processor, the steps of any of the above vacuum degree detection methods are implemented.

[0018] The vacuum detection circuit, vacuum gauge and vacuum detection method provided by the embodiments of the present invention are configured by setting a carrier generation module, a capacitance detection module and an output processing module connected in sequence, and setting a capacitance bridge including an inner ring capacitance of a thin film capacitor in the capacitance detection module. The inner ring capacitance produces a change in capacitance under the action of gas pressure, and the carrier is used as the voltage input end of the capacitance bridge. The switching circuit is controlled by a square wave with the same frequency as the carrier, and the switching circuit is connected to the two midpoint voltage signals of the capacitance bridge when the square wave changes direction. The signal output by the switching circuit is processed by the output processing module to obtain a DC voltage signal reflecting the vacuum degree. The circuit adopts an analog circuit design, which greatly reduces system noise and reduces system cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solution of the present invention, the following is a brief introduction to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 This is a structural diagram of an existing capacitive thin film vacuum gauge detection circuit based on a digital solution;

[0021] Figure 2 This is one of the structural diagrams of the vacuum detection circuit provided by an embodiment of the present invention;

[0022] Figure 3 This is one of the structural diagrams of the capacitance detection module of the vacuum detection circuit provided by an embodiment of the present invention;

[0023] Figure 4 This is the second structural diagram of the capacitance detection module of the vacuum detection circuit provided by an embodiment of the present invention;

[0024] Figure 5 1 is a schematic diagram of test results of a vacuum detection circuit provided by an embodiment of the present invention;

[0025] Figure 6 This is a schematic diagram of the test results of the vacuum detection circuit of the existing digital solution;

[0026] Figure 7 This is the third structural diagram of the capacitance detection module of the vacuum detection circuit provided by an embodiment of the present invention;

[0027] Figure 8 This is the fourth structural diagram of the capacitance detection module of the vacuum detection circuit provided by an embodiment of the present invention;

[0028] Figure 9This is the fifth structural diagram of the capacitance detection module of the vacuum detection circuit provided by an embodiment of the present invention;

[0029] Figure 10 This is the sixth structural diagram of the capacitance detection module of the vacuum detection circuit provided by an embodiment of the present invention;

[0030] Figure 11 This is the second structural diagram of the vacuum detection circuit provided by an embodiment of the present invention;

[0031] Figure 12 1 is a flow chart of a vacuum degree detection method provided by an embodiment of the present invention;

[0032] Figure 13 It is a structural diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0033] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0034] The vacuum detection circuit provided in the embodiment of the present invention is a vacuum detection circuit based on a thin film capacitor and implemented by an analog circuit.

[0035] Figure 2 This is one of the structural diagrams of the vacuum detection circuit provided by the embodiment of the present invention. Figure 2 As shown, the vacuum detection circuit includes: a carrier generation module 10, a capacitance detection module 20 and an output processing module 30 connected in sequence.

[0036] Figure 3 This is one of the structural diagrams of the capacitance detection module of the vacuum detection circuit provided by an embodiment of the present invention. Figure 4 This is the second structural diagram of the capacitance detection module of the vacuum detection circuit provided by the embodiment of the present invention. Figure 2 、 Figure 3 、 Figure 4 As shown:

[0037] The capacitance detection module 20 includes a switching circuit 201, a square wave signal generating circuit 202, and a capacitance bridge composed of a first capacitor C1, a second capacitor C2, a reference capacitor Cref, and an inner loop capacitor Cx of a thin film capacitor. The first capacitor C1 and the second capacitor C2 have the same capacitance value, and the reference capacitor Cref has the same capacitance value as the inner loop capacitor Cx in a vacuum state. A common point between the first capacitor C1 and the inner loop capacitor Cx is connected to a first signal input terminal of the switching circuit 201, and a common point between the second capacitor C2 and the reference capacitor Cref is connected to a second signal input terminal of the switching circuit 201.

[0038] The common point of the first capacitor C1 and the second capacitor C2 is connected to the carrier output terminal of the carrier generation module 10, and the common point of the reference capacitor Cref and the inner loop capacitor Cx is grounded (e.g. Figure 3 shown);

[0039] Alternatively, the common point of the first capacitor C1 and the second capacitor C2 is grounded, and the common point of the reference capacitor Cref and the inner loop capacitor Cx is connected to the carrier output terminal (e.g. Figure 4 shown);

[0040] The signal output end of the square wave signal generating circuit 202 is connected to the switch enable port of the switching circuit 201. The square wave signal generating circuit 202 outputs a square wave signal with the same frequency as the carrier output by the carrier generating module 10. When the square wave signal changes direction, the signal output end of the switching circuit 201 switches between being connected to the first signal input end and being connected to the second signal input end.

[0041] The signal output end of the switch circuit 201 is connected to the input end of the output processing module 30 , and the output processing module 30 processes the received signal to obtain a DC voltage signal reflecting the vacuum degree.

[0042] To test the vacuum level of the gas, the inner ring capacitor Cx of the film capacitor is connected to a capacitor bridge, taking advantage of the fact that the distance between the capacitor plates changes with increasing gas pressure, thereby affecting its capacitance. The carrier generation module 10 generates a carrier signal and loads it onto the capacitor bridge. The midpoint voltage amplitude of the capacitor bridge arm reflects the change in the inner ring capacitance of the film capacitor, thereby determining the change in the vacuum level of the gas.

[0043] The vacuum degree detection circuit provided by the embodiment of the present invention includes a carrier generation module 10, a capacitance detection module 20 and an output processing module 30 connected in sequence. The carrier generation module 10 generates a sinusoidal carrier with adjustable amplitude, which can be implemented by an oscillation circuit, such as a Wien bridge circuit, an LC sine wave oscillation circuit, etc. The capacitance detection module 20 includes a switching circuit 201, a square wave signal generation circuit 202 and a capacitance bridge composed of a first capacitor C1, a second capacitor C2, a reference capacitor Cref and an inner ring capacitor Cx of a thin film capacitor. The capacitance values of the first capacitor C1 and the second capacitor C2 are the same, and the capacitance value of the reference capacitor Cref is the same as that of the inner ring capacitor Cx in a vacuum state, which is expressed as:

[0044] C1=C2,C ref =C x (1)

[0045] Where: C1 represents the capacitance value of the first capacitor C1, C2 represents the capacitance value of the second capacitor C2, C ref Indicates the capacitance value of the reference capacitor Cref, C x It indicates the capacitance value of the inner ring capacitance Cx of the film capacitor in a vacuum state, or is called the initial capacitance value of the inner ring capacitance Cx of the film capacitor. The capacitance value of the inner ring capacitance Cx will change under the influence of the measured air pressure.

[0046] The common point of the first capacitor C1 and the inner loop capacitor Cx is connected to the first signal input terminal of the switch circuit 201, and the common point of the second capacitor C2 and the reference capacitor Cref is connected to the second signal input terminal of the switch circuit 201. In other words, the two midpoint voltages of the capacitor bridge are connected to the first signal input terminal and the second signal input terminal of the switch circuit 201.

[0047] Switch circuit 201 switches between the signal output terminal and the first and second signal input terminals under the influence of an input square wave signal. When the square wave signal is high, the first signal input terminal is connected; when the square wave signal is low, the second signal input terminal is connected. Switch circuit 201 can be an existing device, such as the MAX4693ETE analog switch.

[0048] The signal output end of the square wave signal generating circuit 202 is connected to the switch enable port of the switch circuit 201. The square wave signal generating circuit 202 outputs a square wave signal with the same frequency as the carrier wave output by the carrier wave generating module 10, that is, the carrier wave and the square wave signal change directions at the same time. Since the carrier wave output end of the carrier wave generating module 10 outputs the carrier wave as the input voltage of the capacitor bridge, when the square wave signal and the carrier wave have the same frequency, the parameters of the capacitor bridge in the initial state (under vacuum state) are as shown in formula (1). The voltage amplitudes of the first signal input end and the second signal input end of the switch circuit 201 are equal. The switch circuit 201 outputs a sine wave with equal amplitudes in the positive half cycle and the negative half cycle. When the capacitance value Cx of the inner ring capacitor of the capacitor to be measured, i.e., the thin film capacitor, changes, the voltage amplitude of the first signal input end will also change. The voltage amplitude of the first signal input end is no longer equal to the voltage amplitude of the second signal input end. The switch circuit 201 will output a sine wave with unequal amplitudes in the positive half cycle and the negative half cycle.

[0049] The signal output terminal of the switching circuit 201 is connected to the input terminal of the output processing module 30. The output processing module 30 processes the received signal to obtain a voltage signal reflecting the vacuum degree. After the output processing module 30 performs low-pass filtering on the signal output from the signal output terminal of the switching circuit 201, a DC component is obtained. The magnitude of this DC component represents the magnitude of the change in the capacitance Cx to be measured, which can reflect the change in the pressure of the gas being measured. The processing operations of the output processing module 30 can include filtering and amplification. An active filtering and signal amplification circuit can be constructed using an operational amplifier. The filtering function is to filter the sine wave output by the switching circuit 201, whose positive and negative half-cycles have unequal amplitudes, and obtain a DC component. The purpose of amplification is to adjust the signal to a voltage range (e.g., 0-10V) that is convenient for measurement and cascading other instruments. In other words, it is to adjust the scale. Within this range, the voltage magnitude can represent the magnitude of the pressure of the gas being measured. After filtering, if the DC component obtained is negative, the DC component can be inverted before or after the amplification process.

[0050] The output voltage of the output processing module and the calibration data of the test air pressure can be obtained in advance based on different test air pressures. After calibration, the output voltage value of the output processing module 30 can represent the measured air pressure value. Therefore, the vacuum degree can be obtained according to the final DC voltage signal.

[0051] If the output voltage is adjusted to the range of 0-10V, the 0-10V voltage can linearly correspond to the pressure value from vacuum to full scale. For example, with a full scale of 0.1torr (pressure unit, Torr), when the pressure to be measured is close to vacuum, the output voltage is close to 0V, and when the pressure to be measured is 0.1torr, the output voltage is 10V.

[0052] If the carrier signal and the square wave signal have the same frequency and phase, then when the carrier signal is in a positive half-cycle, the signal at the first signal input terminal is in a positive half-cycle, the switch circuit 201 is connected to the first signal input terminal, and the waveform output by the switch circuit 201 is also a positive half-cycle. When the carrier signal is in a negative half-cycle, the signal at the second signal input terminal is in a negative half-cycle, the switch circuit 201 is connected to the second signal input terminal, and the waveform output by the switch circuit 201 is also a negative half-cycle. If the carrier signal and the square wave signal have the same frequency but different phases, the waveform output by the switch circuit 201 will be in opposite phases.

[0053] Based on Figure 2 and Figure 3 In the vacuum detection circuit shown, the common point of the first capacitor C1 and the second capacitor C2 is connected to the carrier output terminal of the carrier generation module 10, and the common point of the reference capacitor Cref and the inner loop capacitor Cx is grounded. The voltage amplitude of the first signal input terminal is:

[0054]

[0055] Among them, V ZB Indicates the amplitude of the carrier.

[0056] The voltage amplitude of the second signal input terminal is:

[0057]

[0058] Taking the carrier signal and the square wave signal with the same frequency and phase as an example, when the inner ring capacitance Cx of the film capacitor decreases due to the increase of gas pressure, the capacitance value C x When it increases, the voltage amplitude V1 of the first signal input terminal decreases, and the voltage amplitude V2 of the second signal input terminal remains unchanged. The output waveform of the switching circuit 201 will obtain a negative DC component after filtering. After inverting and amplifying the DC component, a DC voltage signal reflecting the pressure is obtained.

[0059] Based on Figure 2 and Figure 4 In the vacuum detection circuit shown, the common point of the first capacitor C1 and the second capacitor C2 is grounded, and the common point of the reference capacitor Cref and the inner loop capacitor Cx is connected to the carrier output terminal of the carrier generation module 10. The voltage amplitude of the first signal input terminal is:

[0060]

[0061] The voltage amplitude of the second signal input terminal is:

[0062]

[0063] Taking the carrier signal and the square wave signal with the same frequency and phase as an example, when the inner ring capacitance Cx of the film capacitor decreases due to the increase of gas pressure, the capacitance value C x When it increases, the voltage amplitude V1 of the first signal input terminal increases, and the voltage amplitude V2 of the second signal input terminal remains unchanged. The output waveform of the switching circuit 201 will obtain a positive DC component after filtering. After amplifying the DC component, a DC voltage signal reflecting the pressure is obtained.

[0064] The sine carrier generated by digital means in the prior art is stepped, which will result in a large noise in the test results. The high-frequency noise of the digital signal will also cause interference, resulting in a large noise in the test results, and the cost is relatively high. The vacuum detection circuit provided in the embodiment of the present invention adopts an analog design scheme, that is, the vacuum detection circuit is designed entirely using analog circuits. In this analog design scheme, except for the carrier signal frequency of the kHz level, the remaining signals are all low-frequency signals and will not bring additional high-frequency interference. In the digital design scheme, the digital signal frequency can even reach the MHz level, which will bring the hidden danger of high-frequency noise interference. In addition, the cost of the digital solution is relatively high. The cost of the analog solution can be reduced by about 3 / 4 compared to the digital solution.

[0065] Figure 5 4 is a schematic diagram of test results of the vacuum detection circuit provided by an embodiment of the present invention. Figure 6 This is a test result diagram of the vacuum detection circuit of the existing digital solution. Figure 5 As shown, taking a vacuum gauge with a range of 0.1Torr as an example, the 12-hour stability test results show that the noise is 0.00359mTorr, which is consistent with the Figure 6 The digital solution shown is less noisy in comparison.

[0066] The vacuum degree detection circuit provided by the embodiment of the present invention is configured by setting a carrier generation module, a capacitance detection module and an output processing module connected in sequence. A capacitance bridge including an inner ring capacitance of a thin film capacitor is configured in the capacitance detection module. The inner ring capacitance produces a change in capacitance under the action of gas pressure. The carrier is used as the voltage input end of the capacitance bridge. A square wave with the same frequency as the carrier is used to control the switching circuit, and the switching circuit is connected to the two midpoint voltage signals of the capacitance bridge when the square wave changes direction. The signal output by the switching circuit is processed by the output processing module to obtain a DC voltage signal reflecting the vacuum degree. The circuit adopts an analog circuit design, which greatly reduces system noise and reduces system cost.

[0067] According to a vacuum degree detection circuit provided by an embodiment of the present invention, the first capacitor C1, the second capacitor C2, the reference capacitor Cref, and the inner loop capacitor Cx of the thin film capacitor have the same capacitance value in a vacuum state.

[0068] In the embodiment of the present invention, the first capacitor C1, the second capacitor C2, the reference capacitor Cref, and the inner ring capacitor Cx of the thin film capacitor have the same capacitance value in a vacuum state. The first capacitor C1, the second capacitor C2, and the reference capacitor Cref are not affected by air pressure, while the inner ring capacitor Cx of the thin film capacitor will change in capacitance under the influence of air pressure.

[0069] The vacuum detection circuit provided by the embodiment of the present invention facilitates simplifying subsequent processing by setting the first capacitor C1, the second capacitor C2, the reference capacitor Cref and the inner loop capacitor Cx of the film capacitor to have the same capacitance value in a vacuum state.

[0070] According to a vacuum degree detection circuit provided by an embodiment of the present invention, the square wave signal generating circuit 202 includes a comparator; wherein the carrier output end of the carrier generating module 10 is connected to the positive input end of the comparator, and the negative input end of the comparator is grounded; or, the carrier output end of the carrier generating module is connected to the negative input end of the comparator, and the positive input end of the comparator is grounded.

[0071] Figure 7 This is the third structural diagram of the capacitance detection module of the vacuum detection circuit provided by the embodiment of the present invention. Figure 7 As shown, the switching signal (square wave signal) of the analog switch is generated by the carrier and GND through the comparator. The carrier is connected to the positive input terminal of the comparator, and GND is connected to the negative input terminal of the comparator. The carrier and the square wave have the same frequency and phase. When the carrier is in the positive half cycle, the analog switch is connected to signal 1, and when the carrier is in the negative half cycle, the analog switch is connected to signal 2. The capacitance values of the first capacitor C1 and the second capacitor C2 are the same, and the initial capacitance values of the reference capacitor Cref and the inner ring capacitor Cx of the thin film capacitor are consistent. The output port of the analog switch can measure a voltage waveform with equal amplitudes in the positive and negative half cycles. The DC component after low-pass filtering in the output link is 0; when the thin film capacitor increases due to the increase in the pressure of the measured gas and the decrease in the film spacing, the voltage amplitude at signal 1 will decrease, and the analog switch will output a waveform with a smaller amplitude in the positive half cycle and a larger amplitude in the negative half cycle. After low-pass filtering in the output link, a negative DC component will be obtained. This negative DC component is inverted and amplified, and the signal can be adjusted to a voltage range that is convenient for measurement and cascading other instruments.

[0072] Figure 8 This is the fourth structural diagram of the capacitance detection module of the vacuum detection circuit provided by the embodiment of the present invention. Figure 8As shown, the switching signal (square wave signal) of the analog switch is generated by the carrier and GND through the comparator. The carrier is connected to the negative input terminal of the comparator, and GND is connected to the positive input terminal of the comparator. The carrier and the square wave have the same frequency but different phases. When the carrier is in the positive half cycle, the analog switch connects to signal 2, and when the carrier is in the negative half cycle, the analog switch connects to signal 1. The capacitance values of the first capacitor C1 and the second capacitor C2 are the same, and the initial capacitance values of the reference capacitor Cref and the inner ring capacitor Cx of the thin film capacitor are consistent. The output port of the analog switch can measure a voltage waveform with equal amplitudes in the positive and negative half cycles. The DC component after low-pass filtering in the output link is 0; when the capacitance value of the thin film capacitor increases due to the increase in the pressure of the measured gas and the decrease in the film spacing, the voltage amplitude at signal 1 will decrease, and the analog switch will output a waveform with a larger amplitude in the positive half cycle and a smaller amplitude in the negative half cycle. After low-pass filtering in the output link, a positive DC component will be obtained. This positive DC component is amplified and the signal can be adjusted to a voltage range that is convenient for measurement and cascading other instruments.

[0073] Figure 9 This is the fifth structural diagram of the capacitance detection module of the vacuum detection circuit provided by the embodiment of the present invention. Figure 9 As shown, the switching signal (square wave signal) of the analog switch is generated by the carrier and GND through the comparator. The carrier is connected to the positive input terminal of the comparator, and GND is connected to the negative input terminal of the comparator. The carrier and the square wave have the same frequency and phase. When the carrier is in the positive half cycle, the analog switch is connected to signal 1, and when the carrier is in the negative half cycle, the analog switch is connected to signal 2. The capacitance values of the first capacitor C1 and the second capacitor C2 are the same, and the initial capacitance values of the reference capacitor Cref and the inner ring capacitor Cx of the thin film capacitor are consistent. The output port of the analog switch can measure a voltage waveform with equal amplitudes in the positive and negative half cycles. The DC component after low-pass filtering in the output link is 0; when the capacitance value of the thin film capacitor increases due to the increase in the pressure of the measured gas and the decrease in the film spacing, the voltage amplitude at signal 1 will increase, and the analog switch will output a waveform with a larger amplitude in the positive half cycle and a smaller amplitude in the negative half cycle. After low-pass filtering in the output link, a positive DC component will be obtained. This positive DC component is amplified and the signal can be adjusted to a voltage range that is convenient for measurement and cascading other instruments.

[0074] Figure 10 This is the sixth structural diagram of the capacitance detection module of the vacuum detection circuit provided by the embodiment of the present invention. Figure 10As shown, the switching signal (square wave signal) of the analog switch is generated by the carrier and GND through the comparator. The carrier is connected to the negative input terminal of the comparator, and GND is connected to the positive input terminal of the comparator. The carrier and the square wave have the same frequency but different phases. When the carrier is in the positive half cycle, the analog switch connects to signal 2, and when the carrier is in the negative half cycle, the analog switch connects to signal 1. The capacitance values of the first capacitor C1 and the second capacitor C2 are the same, and the initial capacitance values of the reference capacitor Cref and the inner ring capacitor Cx of the thin film capacitor are consistent. The output port of the analog switch can measure a voltage waveform with equal amplitudes in the positive and negative half cycles. The DC component after low-pass filtering in the output link is 0; when the capacitance value of the thin film capacitor increases due to the increase in the pressure of the measured gas and the decrease in the film spacing, the voltage amplitude at signal 1 will increase, and the analog switch will output a waveform with a larger amplitude in the negative half cycle and a smaller amplitude in the positive half cycle. After low-pass filtering in the output link, a negative DC component will be obtained. This negative DC component is inverted and amplified, and the signal can be adjusted to a voltage range that is convenient for measurement and cascading other instruments.

[0075] The vacuum detection circuit provided in the embodiment of the present invention can ensure the same frequency relationship between the square wave signal and the carrier signal by inputting the carrier and GND signals into the comparator to obtain the square wave signal. It is simple and convenient, and there is no need to build other signal generating circuits, thereby achieving the simplicity and reliability of square wave signal acquisition and further reducing costs.

[0076] According to a vacuum degree detection circuit provided by an embodiment of the present invention, the reference capacitor is an outer ring capacitor of the thin film capacitor.

[0077] The upper and lower plates of the outer ring capacitor and the inner ring capacitor of the film capacitor are made of the same material, and under the action of gas pressure, the capacitance value of the outer ring capacitor can be considered unchanged (the change is very small and can be ignored). Using the outer ring capacitor as a reference capacitor can make the capacitance changes of the inner ring capacitor and the reference capacitor of the film capacitor consistent under the action of temperature due to the same material of the capacitor, thereby reducing or offsetting the influence of temperature and improving the reliability of detection.

[0078] The vacuum detection circuit provided by the embodiment of the present invention improves the reliability of vacuum detection by utilizing the outer ring capacitance of the film capacitor as a reference capacitance.

[0079] According to an embodiment of the present invention, a vacuum detection circuit is provided, which further includes a first negative feedback module; wherein the input end of the first negative feedback module is connected to the carrier output end of the carrier generation module 10, and the output end of the first negative feedback module is connected to the signal input end of the carrier generation module.

[0080] The vacuum detection circuit also includes a first negative feedback module, the input end of the first negative feedback module is connected to the carrier output end of the carrier generation module 10, and the output end of the first negative feedback module is connected to the signal input end of the carrier generation module. The first negative feedback module is used to compare the actual value of the carrier with the expected value to realize automatic gain control of the carrier amplitude and achieve the purpose of stabilizing the amplitude.

[0081] The vacuum degree detection circuit provided in the embodiment of the present invention realizes automatic gain control of the carrier amplitude by providing the first negative feedback module, thereby achieving the purpose of stabilizing the amplitude.

[0082] Figure 11 This is the second structural diagram of the vacuum detection circuit provided by the embodiment of the present invention. Figure 11 As shown, the first negative feedback module includes a first low-pass filter 40, a first proportional operation circuit 50 and a PI adjustment module 60 connected in sequence; wherein, the input end of the first low-pass filter 40 is connected to the carrier output end of the carrier generation module 10, and the output end of the PI adjustment module 60 is connected to the signal input end of the carrier generation module 10.

[0083] The embodiment of the present invention utilizes a PI (proportional-integral) regulation module 60 to implement the construction of the first negative feedback module. Before the signal at the carrier output end of the carrier generation module 10 is input to the PI regulation module 60, it is first filtered using a first low-pass filter 40 to obtain a DC signal, and then amplitude-adjusted by a first proportional operation circuit 50 to obtain a signal suitable for processing by the PI regulation module 60.

[0084] The vacuum detection circuit provided in the embodiment of the present invention improves the reliability of amplitude stabilization processing by constructing a first negative feedback module using a first low-pass filter, a first proportional operation circuit and a PI adjustment module.

[0085] According to an embodiment of the present invention, a vacuum detection circuit is provided, which further includes a second negative feedback module; wherein the input end of the second negative feedback module is connected to the signal output end of the switching circuit 201, and the output end of the second negative feedback module is connected to the signal input end of the carrier generation module.

[0086] The vacuum detection circuit also includes a second negative feedback module, the input end of the second negative feedback module is connected to the signal output end of the switching circuit 201, and the output end of the first negative feedback module is connected to the signal input end of the carrier generation module. The second negative feedback module is used to perform nonlinear compensation on the system so that the output voltage of the output processing module 30 and the measured air pressure are as close to or reach a linear relationship as possible, thereby improving the linearity and accuracy of the measurement.

[0087] The vacuum degree detection circuit provided by the embodiment of the present invention improves the linearity and accuracy of vacuum degree detection by providing a second negative feedback module.

[0088] According to an embodiment of the present invention, a vacuum detection circuit is provided. Figure 11 As shown, the second negative feedback module includes a second low-pass filter 70, a second proportional operation circuit 80 and the PI adjustment module 60 connected in sequence; wherein the input end of the second low-pass filter 70 is connected to the signal output end of the switch circuit 201.

[0089] The embodiment of the present invention further implements the construction of the second negative feedback module using a PI (proportional-integral) regulation module 60. Before the signal at the signal output terminal of the switching circuit 201 is input to the PI regulation module 60, it is first filtered by the second low-pass filter 40 to obtain a DC signal, and then amplitude-adjusted by the second proportional operation circuit 50 to obtain a signal suitable for processing by the PI regulation module 60.

[0090] The vacuum detection circuit provided in the embodiment of the present invention improves the reliability of nonlinear compensation by constructing a second negative feedback module using a second low-pass filter, a second proportional operation circuit and a PI adjustment module.

[0091] An embodiment of the present invention further provides a vacuum gauge (also referred to as a vacuum gauge), which includes any vacuum degree detection circuit in the above embodiments.

[0092] Figure 12 FIG. 1 is a flow chart of the vacuum degree detection method provided by an embodiment of the present invention. Figure 12 As shown, the vacuum degree detection method provided by an embodiment of the present invention is based on the vacuum degree detection circuit provided by any of the above embodiments, and the method includes:

[0093] Step S1: Based on different test gas pressures, calibration data of the output voltage and test gas pressure of the output processing module are obtained.

[0094] First, you need to obtain calibration data in advance. This data reflects the relationship between the output voltage of the output processing module and the test pressure. You can obtain calibration data for the output voltage and test pressure of the output processing module based on different test pressures.

[0095] Step S2: obtaining the current measured air pressure value according to the calibration data and the voltage signal output by the output processing module during actual measurement.

[0096] During actual measurement, the voltage signal output during actual measurement is compared with the calibration data to obtain the current measured air pressure value.

[0097] The vacuum degree detection method provided by the embodiment of the present invention realizes the simple acquisition of vacuum degree values by using data calibration.

[0098] Figure 13 Schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. Figure 8 As shown, the electronic device may include: a processor 810, a communications interface 820, a memory 830, and a communications bus 840, wherein the processor 810, the communications interface 820, and the memory 830 communicate with each other via the communications bus 840. The processor 810 may call logic instructions in the memory 830 to execute a vacuum detection method, which includes: obtaining the output voltage of the output processing module and calibration data of the test pressure based on different test pressures; and obtaining the current measured pressure value based on the calibration data and the voltage signal output by the output processing module during actual measurement.

[0099] In addition, the logic instructions in the above-mentioned memory 830 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when sold or used as an independent product. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0100] On the other hand, an embodiment of the present invention also provides a computer program product, which includes a computer program. The computer program can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the vacuum detection method provided by the above methods. The method includes: obtaining the output voltage of the output processing module and the calibration data of the test air pressure based on different test air pressures; obtaining the current measured air pressure value according to the calibration data and the voltage signal output by the output processing module during actual measurement.

[0101] On the other hand, an embodiment of the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, it is implemented to execute the vacuum detection method provided by the above-mentioned methods. The method includes: obtaining the output voltage of the output processing module and the calibration data of the test air pressure based on different test air pressures; obtaining the current measured air pressure value according to the calibration data and the voltage signal output by the output processing module during actual measurement.

[0102] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, i.e., they may be located in one location or distributed across multiple network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of the present embodiment. Persons of ordinary skill in the art will be able to understand and implement the present invention without inventive effort.

[0103] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, or of course, by hardware. Based on this understanding, the essence of the above technical solution or the part that contributes to the existing technology can be embodied in the form of a software product. The computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a magnetic disk, an optical disk, etc., and includes a number of instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or certain parts of the embodiments.

[0104] Finally, it should be noted that 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 they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A vacuum detection circuit, characterized in that: It includes a carrier generation module, a capacitance detection module and an output processing module connected in sequence; wherein: The capacitance detection module includes a switching circuit, a square wave signal generating circuit, and a capacitance bridge composed of a first capacitor, a second capacitor, a reference capacitor, and an inner ring capacitor of a film capacitor, wherein the capacitance values of the first capacitor and the second capacitor are the same, and the capacitance value of the reference capacitor is the same as the capacitance value of the inner ring capacitor in a vacuum state; a common point of the first capacitor and the inner ring capacitor is connected to a first signal input terminal of the switching circuit, and a common point of the second capacitor and the reference capacitor is connected to a second signal input terminal of the switching circuit; A common point of the first capacitor and the second capacitor is connected to the carrier output terminal of the carrier generation module, and a common point of the reference capacitor and the inner loop capacitor is grounded; or a common point of the first capacitor and the second capacitor is grounded, and a common point of the reference capacitor and the inner loop capacitor is connected to the carrier output terminal of the carrier generation module; The signal output end of the square wave signal generating circuit is connected to the switch enable port of the switching circuit, and the square wave signal generating circuit outputs a square wave signal with the same frequency as the carrier output by the carrier generating module. When the square wave signal changes direction, the signal output end of the switching circuit switches between being connected to the first signal input end and being connected to the second signal input end; The signal output end of the switch circuit is connected to the input end of the output processing module, and the output processing module obtains a DC voltage signal reflecting the vacuum degree by processing the received signal.

2. The vacuum detection circuit according to claim 1, characterized in that: The first capacitor, the second capacitor, the reference capacitor, and the inner ring capacitor of the thin film capacitor have the same capacitance value in a vacuum state.

3. The vacuum detection circuit according to claim 1, characterized in that: The square wave signal generating circuit includes a comparator; wherein, the carrier output end of the carrier generating module is connected to the positive input end of the comparator, and the negative input end of the comparator is grounded; or, the carrier output end of the carrier generating module is connected to the negative input end of the comparator, and the positive input end of the comparator is grounded.

4. The vacuum detection circuit according to claim 1, characterized in that: The reference capacitor is the outer ring capacitor of the thin film capacitor.

5. The vacuum detection circuit according to claim 1, wherein: The vacuum detection circuit further includes a first negative feedback module; wherein the input end of the first negative feedback module is connected to the carrier output end of the carrier generation module, and the output end of the first negative feedback module is connected to the signal input end of the carrier generation module.

6. The vacuum detection circuit according to claim 5, characterized in that: The first negative feedback module includes a first low-pass filter, a first proportional operation circuit and a PI adjustment module connected in sequence; wherein the input end of the first low-pass filter is connected to the carrier output end of the carrier generation module, and the output end of the PI adjustment module is connected to the signal input end of the carrier generation module.

7. The vacuum degree detection circuit according to claim 6, characterized in that: The vacuum detection circuit further includes a second negative feedback module; wherein the input end of the second negative feedback module is connected to the signal output end of the switch circuit, and the output end of the second negative feedback module is connected to the signal input end of the carrier generation module.

8. The vacuum degree detection circuit according to claim 7, characterized in that: The second negative feedback module includes a second low-pass filter, a second proportional operation circuit and the PI adjustment module connected in sequence; wherein the input end of the second low-pass filter is connected to the signal output end of the switch circuit.

9. A vacuum gauge, characterized in that: The vacuum detection circuit comprises the vacuum detection circuit according to any one of claims 1 to 8.

10. A vacuum degree detection method based on the vacuum degree detection circuit according to any one of claims 1 to 8, characterized in that: include: Based on different test gas pressures, obtain calibration data of the output voltage and test gas pressure of the output processing module; The current measured air pressure value is obtained according to the calibration data and the voltage signal output by the output processing module during actual measurement.

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