A high-precision detection device for gate high voltage

Abstract

The application belongs to the technical field of space plasma environment detection, and relates to a high-precision detection device for gated high voltage, which comprises a level processing circuit, is realized based on a field effect tube, is used for filtering a high voltage part of input gated high voltage, and only outputs low voltage; an ADC conversion circuit is used for periodically outputting gated high voltage level data after analog-digital conversion at a set frequency under the control of a data processing unit; and the data processing unit is realized based on FPGA, is used for controlling the ADC conversion circuit, collecting level data output by the ADC conversion circuit, and packing and outputting the level data to a PC end through an RS422 interface. By using the device, the measurement range of an oscilloscope is reduced from 300V to 3V, and the measurement precision is improved from 50V / div to 0.5V / div, so that the problem of low measurement precision of high-low level switching of gated high voltage is solved, and the risk of high voltage discharge caused by direct measurement of high voltage by an oscilloscope probe is avoided.

Description

[0001] This application is a divisional application of the invention application with application number "2025101041613", invention title "A Low-Level High-Precision Detection Device Based on Field-Effect Transistor Gated High Voltage", and application date of January 23, 2025. Technical Field

[0002] This invention belongs to the field of space plasma environment detection technology, and in particular relates to a high-precision detection device for gated high voltage. Background Technology

[0003] In space plasma environment detection, ion energy, orientation, flux, and mass spectrometry are crucial detection elements. Among these, gated high voltage has extensive applications in plasma flux measurement and ion mass spectrometry analysis. The stable level of the gated high voltage after switching between high and low levels is an important parameter for evaluating its performance.

[0004] Firstly, gated high voltage is mainly used for flux control in ionospheric ion imaging detection. Typical ionospheric probe satellites orbit at 340–450 km, and the total variation range of their ion differential flux reaches approximately eight orders of magnitude (5 × 10⁻⁶). 6 cm-2s-1sr-1eV-1~5×10 14 The dynamic range (cm⁻²s⁻¹sr⁻¹eV⁻¹) is relatively large, representing a typical region for high-flux ions. Ion imaging detection works by amplifying and imaging individual ion charge signals using a microchannel plate (MCP) and a fluorescent screen, allowing for detailed analysis of ion density, temperature, drift velocity, and spatial distribution of ion composition, offering advantages in high spatiotemporal analysis. However, such ion imaging detection instruments will saturate and malfunction without flux control when measuring in environments with extremely high ion flux in the ionosphere. Figure 1 The diagram shows a cross-sectional view of the ion imager design. A gated electrode is set at the ion inlet to limit the incident ion beam by applying a gated high voltage. When the gated high voltage output is high, the gate is closed to prevent ions from entering; when the output is low, the gate is open to allow ions to enter, thereby ensuring that the microchannel plate (MCP) and the fluorescent screen operate within a suitable dynamic range.

[0005] Secondly, gated high voltage is a key technology in mass spectrometry analysis based on time-of-flight measurement systems. The basic principle of a mass spectrometer based on a time-of-flight measurement system is: Where m is the ion mass (unit: kilogram), and v is the ion velocity (unit: m / s). The flight velocity v can be calculated from the ion flight time T, and the ion energy E is calculated using the high-voltage amplitude of the electrostatic analyzer; combined with... Information on ionic composition can be deduced.

[0006] As Figure 2 shown in the application of the gated high voltage in the time-of-flight measurement system, TDC-GPX is a time-of-flight measurement chip, which measures the time interval between the start signal START and the stop signal STOP. The gated high voltage output by the gated high voltage module is used to control the "gate opening" of the gate electrode: that is, to allow the incident ions to enter, and at the same time, as the start signal START of the time-of-flight measurement of TDC-GPX, the incident ions reach the detector after passing through the free flight region with a distance of L, and output a digital pulse as the stop signal STOP of the time-of-flight measurement of TDC-GPX, and finally TDC-GPX gives the time-of-flight of the incident ions.

[0007] As Figure 3 shown, the gated high voltage is characterized by that the output voltage is periodically switched between high level and low level at a fixed frequency, and the high level and low level pulse width is fixed. In the application of the plasma detector, there are index requirements for the high and low level amplitudes of the gated high voltage, the switching time of the high and low levels, the minimum pulse width, and the stable state of the level after switching. The gated high voltage used for ion flux control requires that the high level be +300V (gate closed), the low level be 0V (gate open), the pulse width be adjustable, the minimum width be 10us, and the switching time of the high and low levels be 100ns. The accurate output of the low level 0V and the effective holding time of the level are required, otherwise the flux control accuracy will be affected. The gated high voltage used for mass spectrometer requires that the high level be +300V (gate closed), the low level be 0V (gate open), the pulse width be adjustable, the minimum width be 30ns, and the switching time of the high and low levels be less than 20ns. The accurate output of the low level 0V and the effective holding time of the level are required, otherwise the mass resolution will be affected.

[0008] Due to the charging and discharging of the parasitic capacitance in the gated high voltage circuit, overshoot phenomenon will occur at the moment of gate opening, which will cause damage to the devices in the gated high voltage circuit and affect the service life of the devices. This overshoot phenomenon can be eliminated by adjusting the resistance and capacitance matching in the circuit, but it is necessary to be able to measure the level stability process after the high and low level switching with high precision.

[0009] In different application scenarios, the level stability state after the high and low level switching of the gated high voltage is an important parameter for evaluating the performance of the gated high voltage, which directly affects the detection index of the detector on the one hand, and affects the reliability of the gated high voltage on the other hand. However, during the debugging process of the gated high voltage circuit, due to the limitation of measurement technology, the measurement accuracy of the level stability state after the high and low level switching of the gated high voltage is low.

[0010] Since the high level output by the gated high voltage is +300V, the voltage amplitude is high, the amplitude difference between the high level and the low level is 300V, and the amplitude difference is large, the switching frequency of the high and low levels is greater than 10kHz, and the low level holding time is less than 10us.

[0011] At present, the high-low level switching process of the gate high-voltage output is measured by an oscilloscope, the oscilloscope needs to cover a range of +300V, and the resolution of the measurement can only reach 50V / div, the accuracy is low, and the stable state of the switched level cannot be accurately measured. In addition, the high level of the gate high-voltage output is high-voltage +300V, and the probe of the oscilloscope directly measures, which has a high-voltage discharge risk and a safety hazard to the tester. SUMMARY

[0012] The purpose of the present application is to overcome the defects of the prior art and provide a high-precision detection device for gate high-voltage.

[0013] Therefore, the present application discloses a high-precision detection device for gate high-voltage, comprising: a level processing circuit, an ADC conversion circuit and a data processing unit, wherein,

[0014] The level processing circuit is realized based on a field effect tube and is used to filter the high-voltage part of the input gate high-voltage and output only low-voltage.

[0015] The ADC conversion circuit is used to periodically output the gate high-voltage level data converted by the ADC under the control of the data processing unit at a set frequency.

[0016] The data processing unit is realized based on FPGA and is used to control the ADC conversion circuit, collect the level data output by the ADC conversion circuit and output the data to the PC end through the RS422 driving circuit after packaging.

[0017] The high level value of the input gate high-voltage is +300V, and the low level value is 0V.

[0018] In the level processing circuit, the breakdown voltage V DS of the field effect tube is 500V, the gate-source conduction threshold voltage V GS is greater than 2V, the gate-source can withstand the rated voltage range of ±20V, the gate voltage V G is fixed at 5V, and the source voltage V S is in the range of 0V-3V, the drain-source D-S is turned on, the source voltage V S is greater than 3V, and the field effect tube drain-source D-S is cut off.

[0019] Preferably, the ADC conversion circuit adopts a 16-bit high-precision ADC converter.

[0020] Preferably, the data processing unit comprises FPGA and RSS422 driving circuit, wherein,

[0021] The FPGA controls the ADC conversion circuit to periodically collect the level data output by the level processing circuit at a frequency of 100 kHz and transmit to the RS422 driving circuit.

[0022] The RS422 driving circuit converts the level data from single-ended signal to differential signal and outputs to the PC end.

[0023] Preferably, the interface signals between the ADC conversion circuit and the FPGA include: ADC data bus, ADC chip selection signal, ADC conversion enable flag signal and ADC conversion completion flag signal.

[0024] Preferably, the PC end stores the data of the high-low level switching process of the gate high voltage and the low level stable state for later data analysis and comparison.

[0025] Compared with the prior art, the advantages of the present application are:

[0026] 1. The present application utilizes the on-off characteristics of the field effect transistor to design a gate high voltage level processing circuit, filters the high voltage part of the gate high voltage and only outputs low voltage, so that after using the present application, the measurement range of the oscilloscope is reduced from 300V to 3V, the measurement accuracy is improved from 50V / div to 0.5V / div, the problem of low measurement accuracy of the gate high voltage high-low level switching is overcome, and the risk of high voltage discharge caused by direct measurement of high voltage by the oscilloscope probe is avoided.

[0027] 2. The present application outputs an analog output interface integrated with the level processing and an RS422 digital output interface, the detection level can be viewed in real time through the oscilloscope, and also can be realized through the data stored by the PC to realize data analysis, comparison and research. DETAILED DESCRIPTION

[0028] Figure 1 is the design profile of the ion imager;

[0029] Figure 2 is the schematic diagram of the time of flight measurement principle based on the gate high voltage;

[0030] Figure 3 is the working schematic diagram of the gate power supply;

[0031] Figure 4 is the schematic block diagram of the low level high precision detection device of the gate high voltage of the present application;

[0032] Figure 5 is the level processing circuit schematic diagram of Figure 4 ;

[0033] Figure 6 is the ADC conversion circuit schematic diagram of Figure 4 ;

[0034] Figure 7 is Figure 4 a data processing unit circuit schematic diagram of the application;

[0035] Figure 8 is the input and output waveform diagram of the low-level high-precision detection device of the application. DETAILED DESCRIPTION

[0036] The application discloses a low-level high-precision detection device of a gate high voltage, comprising a level processing circuit, an ADC conversion circuit and a data processing unit, wherein,

[0037] The level processing circuit is realized based on a field effect tube, is used for filtering a high voltage part of the input gate high voltage, and only outputs a low voltage;

[0038] The ADC conversion circuit is used for periodically outputting gate high voltage level data converted from analog to digital under the control of the data processing unit at a set frequency;

[0039] The data processing unit is realized based on an FPGA (Field-Programmable Gate Array), is used for controlling the ADC conversion circuit, collecting level data output by the ADC conversion circuit, and outputting the level data to a PC end through an RS422 driving circuit in a package.

[0040] The technical solutions of the application will be described in detail below in combination with the drawings and embodiments.

[0041] EMBODIMENT

[0042] The embodiment of the application provides a low-level high-precision detection device of a gate high voltage. Figure 4 As shown in the schematic block diagram of the low-level high-precision detection device of the gate high voltage, the detection device comprises a level processing circuit, an ADC conversion circuit and a data processing unit, the analog input of the detection device is a gate high voltage, the output of the detection device is a low voltage part of the processed gate high voltage, the detection device can be measured by using an oscilloscope, and the detection device has an RS422 interface and can output packaged data collected.

[0043] As shown in the schematic block diagram of the low-level high-precision detection device of the gate high voltage, the detection device comprises a level processing circuit, an ADC conversion circuit and a data processing unit, the analog input of the detection device is a gate high voltage, the output of the detection device is a low voltage part of the processed gate high voltage, the detection device can be measured by using an oscilloscope, and the detection device has an RS422 interface and can output packaged data collected. Figure 5 As shown in the schematic block diagram of the low-level high-precision detection device of the gate high voltage, the detection device comprises a level processing circuit, an ADC conversion circuit and a data processing unit, the analog input of the detection device is a gate high voltage, the output of the detection device is a low voltage part of the processed gate high voltage, the detection device can be measured by using an oscilloscope, and the detection device has an RS422 interface and can output packaged data collected. DSThe gate high voltage will have overshoot phenomenon at the moment of opening the door due to the charging and discharging of the parasitic capacitance in the gate high voltage circuit, which will cause damage to the devices in the gate high voltage circuit and affect the service life of the devices.

[0044] As shown in Figure 6 , Figure 7 The low-precision detection device of the gate high voltage is shown in the schematic diagram of the ADC conversion circuit and the schematic diagram of the data processing unit circuit, in an embodiment, the ADC converter adopts AD976, a 16-bit high-precision ADC converter, and the interface signals between the data processing unit FPGA include: ADC data bus, ADC chip selection signal, ADC conversion enable flag signal, and ADC conversion completion flag signal.

[0045] As shown in Figure 8 , the input and output voltage waveform diagram of the level processing circuit, the input voltage range is 0~+300V, and the output voltage range is 0~+3V. The highest output voltage is +3V, and the output end is connected to the ADC conversion circuit in the device, and an external analog output is also introduced, which can be measured by an oscilloscope with high precision. The output voltage of the device is 0~+3V, which is within the safe voltage range of human body, and the tester has no safety problem.

[0046] By using the device of the application, the low-level stable process, low-level amplitude and low-level holding time after the high-low level switching of the gate high voltage can be measured with high precision, and the overshoot phenomenon can be effectively avoided by adjusting the related resistance-capacitance matching state in the gate high voltage circuit. The accurate measurement of low-level amplitude and low-level holding time can effectively ensure the high-precision measurement of flux control and mass spectrometry instruments.

[0047] The application overcomes the problem of low measurement precision of gate high voltage high-low level switching, avoids direct measurement of high voltage by oscilloscope probe, and can effectively prevent high voltage discharge risk. The application utilizes the conduction and shutdown characteristics of field effect transistor to design a gate high voltage level measurement circuit, filters the high voltage part of the gate high voltage, and only outputs low voltage. After using the application, the measurement range of the oscilloscope is reduced from 300V to 3V, and the measurement precision is improved from 50V / div to 0.5V / div. The specific performance indicators are shown in Table 1:

[0048] Table 1

[0049]

[0050] Finally, it should be noted that the above examples are merely intended to illustrate the technical solutions of the present application and not to limit. Although the present application is described in detail with reference to the examples, those skilled in the art should understand that the technical solutions of the present application are modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present application, and they should be covered in the scope of the claims of the present application.

Claims

1. A high-precision detection device for gated high voltage, characterized in that, The application relates to a high-voltage level processing circuit, which comprises a level processing circuit, an ADC conversion circuit and a data processing unit, wherein, the level processing circuit is realized based on a field effect tube and is used for filtering a high-voltage part of input gate high voltage, outputting only low voltage and viewing in real time through an oscilloscope; the high level and the low level of the gate high voltage are periodically switched at a fixed frequency, and the high level and the low level have fixed pulse widths; the ADC conversion circuit is used for periodically outputting gate high voltage level data converted from analog to digital under the control of the data processing unit at a set frequency; the data processing unit is realized based on FPGA and is used for controlling the ADC conversion circuit, collecting level data output by the ADC conversion circuit, packing the level data through an RS422 interface and outputting the level data to a PC end for storage, and realizing data analysis, comparison and research; the high level value of the input gate high voltage is +300V, and the low level value is 0V; the ADC conversion circuit adopts a 16-bit high-precision ADC converter. The breakdown voltage V DS of the field effect transistor in the level processing circuit is 500V, the gate-source conduction threshold voltage V GS is greater than 2V, the gate-source tolerable rated voltage range is ±20V, the gate voltage V G is fixed at 5V, the source voltage V S is in the range of 0V-3V, the drain-source D-S is turned on, the source voltage V S is greater than 3V, and the field effect transistor drain-source D-S is turned off.

2. The high-precision detection device of gated high voltage according to claim 1, characterized in that, the data processing unit comprises FPGA and an RSS422 driving circuit, wherein, 3. The high-precision detection device of gated high voltage according to claim 1, characterized in that, the FPGA controls the ADC conversion circuit to periodically collect level data output by the level processing circuit at a frequency of 100kHz and transmit the level data to the RS422 driving circuit; the RS422 driving circuit converts the level data from single-end signals into differential signals and outputs the differential signals to the PC end. interface signals between the ADC conversion circuit and the FPGA include an ADC data bus, an ADC chip selection signal, an ADC conversion enabling flag signal and an ADC conversion completion flag signal.

4. The high-precision detection device of gated high voltage according to claim 3, characterized in that, the PC end stores data of high-low level switching processes and low level stable states of the gate high voltage, and the data is used for later data analysis and comparison.

5. The high-precision detection device of gated high voltage according to claim 3, characterized in that, ​

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