A bipolar wide-range current detection system, ion current detection system, method

Abstract

The application discloses a bipolar wide-range current detection system, an ion current detection system and a method, and belongs to the field of ion pump ion current measurement. The technical key points are as follows: a sampling resistor network is used to collect current signals and convert the current signals into voltage signals; a multi-path analog switch can switch the output channels of the sampling resistor network; a programmable gain amplifier is used to adjust the amplification multiple of the signals transmitted by the multi-path analog switch; a differential analog-to-digital converter is used to convert analog signals into digital signals; and a microprocessor is in bidirectional communication connection with the multi-path analog switch, the programmable gain amplifier and the differential analog-to-digital converter. The technical scheme can realize the detection of the ion current of an ion pump.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of ion pump ion current measurement, and more particularly to a bipolar wide-range current detection system, an ion current detection system and a method. BACKGROUND

[0002] The working principle of an ion pump is to ionize gas molecules through an electric field and thermal collision. High-speed moving ions are accelerated under the action of an electromagnetic field and hit the pump wall, thereby realizing the pumping effect.

[0003] Ion pumps are divided into the following two types according to the composition of the pumped gas:

[0004] (1) Diode ion pump: the electrical structure is that the anode cylinder is connected to a positive high voltage, and the cathode is connected to a negative voltage, i.e., ground. The diode ion pump has a very high pumping speed for oxygen, nitrogen, carbon dioxide, carbon monoxide and other active gases. That is, the diode ion pump has strong pumping capacity for active gases, but weak pumping capacity for inert gases and hydrogen, and small pumping speed. Generally speaking, the pumping speed of an ordinary diode ion pump for inert argon gas is only 1% of that for nitrogen.

[0005] (2) Triode ion pump: the electrical structure is that the anode cylinder is connected to ground, the cathode is connected to a negative high voltage, and the pump wall is connected to ground. Compared with the diode ion pump, the triode ion pump also has a very high pumping speed for non-active gases such as methane, argon and helium.

[0006] For an ion pump, the vacuum degree of the ion pump can generally be determined by measuring the discharge current (i.e., ion current). However, the ion current is very small: when the vacuum degree is about 10 -4 Pa, the ion current is about 10-100 microamperes, when the vacuum degree is about 10 -6 Pa, the ion current is about 0.1-1 microamperes, and when the vacuum degree is about 10 -8 Pa, the ion current is about 0.001-0.01 microamperes. As can be seen, the ion current is very susceptible to external and measurement circuit noise interference. This also puts higher requirements on the micro-current measurement system.

[0007] For such a micro-current measurement system,

[0008] The first technical route: collecting the micro-current signal, extracting and amplifying the micro-current signal, analog-to-digital conversion, and displaying the results. For example, document 1: CN116221096A. This technical route needs to use a negative feedback method to amplify the micro-current signal. However, the negative feedback method will also amplify the common-mode interference.

[0009] The second technical route: using I / V conversion circuit to convert micro-current signal into voltage signal for amplification detection. For example, document 2: CN215005601U, document 3: Sun Jian, Li Detian, Wang Yongjun, et al. Micro-ionic flow detection technology in ultra-high vacuum measurement [J]. Vacuum and low temperature, 2016, 22(2): 75-80, document 4: Yao Peng, Li Detian, Zhang Huzhong, et al. Ultra-high vacuum meter weak ion flow detection technology research [J]. Vacuum and low temperature, 2023, 29(2): 111-116. However, the above documents all rely on negative feedback current-voltage structure, at the same time, in order to avoid the influence of background noise and the offset voltage of the previous operational amplifier, digital zero adjustment circuit is necessary. However, the negative feedback mode will amplify the common mode interference at the same time.

[0010] In summary, it is necessary to develop a detection system suitable for ion pump ion flow. SUMMARY

[0011] The purpose of the present application is to overcome the shortcomings of the prior art, and provide a bipolar wide-range current detection system.

[0012] Another purpose of the present application is to provide an ion pump ion flow detection system.

[0013] Still another purpose of the present application is to provide a detection method for ion pump ion flow.

[0014] The technical scheme of the present application is as follows:

[0015] A bipolar wide-range current detection system comprises:

[0016] a, a sampling resistor network for collecting current signals and converting them into voltage signals; the sampling resistor network comprises: first resistor to fourth resistor R1 to R4, fifth resistor to ninth resistor R5 to R9 connected in series between external current loops; the second ends of R1 to R4 are both connected with forward electrode tube, reverse electrode tube and capacitor in parallel; the directions of the forward electrode tube and the reverse electrode tube are opposite; the second end of Ri is connected with the first end of Ri+1, i is any natural number from 1 to 3; the first ends of R1 to R4 are connected with the first ends of R5 to R8 respectively, and the second end of R4 is connected with the first end of R9; the second ends of R5 to R9 are connected with the input ends of the multi-channel analog switch;

[0017] b, a multi-channel analog switch connected with multiple output channels of the sampling resistor network, which can switch the output channels of the sampling resistor network;

[0018] c, a programmable gain amplifier for adjusting the amplification multiple of the signal transmitted by the multi-channel analog switch;

[0019] d, a differential analog-to-digital converter, which is used for converting an analog signal into a digital signal;

[0020] e, a microprocessor, the microprocessor is in bidirectional communication connection with the multiplexing analog switch, the programmable gain amplifier and the differential analog-to-digital converter; the microprocessor can send a control instruction to the multiplexing analog switch to switch the output channel of the sampling resistor network and send a control instruction to the programmable gain amplifier to adjust the gain effect of the programmable gain amplifier according to the value collected by the differential analog-to-digital converter;

[0021] wherein a first-order low-pass filter is arranged between the multiplexing analog switch and the programmable gain amplifier;

[0022] wherein a second-order low-pass filter is arranged between the programmable gain amplifier and the differential analog-to-digital converter.

[0023] Further, the multiplexing analog switch adopts ADG1209, which contains S1A-S4A pins and S1B-S4B pins;

[0024] The second end of R5 is connected to the S1A pin;

[0025] The second end of R6 is connected to the S2A and S1B pins;

[0026] The second end of R7 is connected to the S3A and S2B pins;

[0027] The second end of R8 is connected to the S4A and S3B pins;

[0028] The second end of R9 is connected to the S4B pin.

[0029] Further, the multiplexing analog switch adopts ADG1209, which contains DA pins and DB pins;

[0030] The programmable gain amplifier adopts PGA281, which contains INP pins and INN pins;

[0031] The first-order low-pass filter is composed of the tenth resistor R10, the eleventh resistor R11 and the fifth capacitor C5;

[0032] The first end of R10 is connected to the DA pin, and the second end is connected to the INP pin;

[0033] The first end of R10 is connected to the DB pin, and the second end is connected to the INN pin;

[0034] C5 is connected between the second end of R10 and the second end of R11.

[0035] Further, the programmable gain amplifier adopts PGA281, which contains VOP pins and VON pins;

[0036] The differential analog-to-digital converter adopts ADS8318, which includes an IN+ pin and an IN- pin;

[0037] The second-stage low-pass filter is composed of a twelfth resistor R12, a thirteenth resistor R13 and a sixth capacitor C6;

[0038] The first end of R12 is connected to the VOP pin, and the second end is connected to the IN+ pin;

[0039] The first end of R13 is connected to the VON pin, and the second end is connected to the IN- pin;

[0040] The second end of R12 and the second end of R13 are connected to C6.

[0041] Further, it further includes a seventh capacitor C7 and an eighth capacitor C8; C7 is arranged between the second end of R13 and AGND, and C7 is arranged between the second end of R12 and AGND.

[0042] An ion pump ion current detection system, the ion current is positive ion current, which adopts the bipolar wide-range current detection system to detect the ion current of the ion pump;

[0043] The second end of R4 of the sampling resistor network is in communication with the shell of the ion pump, and the first end of R1 of the sampling resistor network is in communication with the negative electrode of the ion pump voltage source.

[0044] An ion pump ion current detection system, the ion current is negative ion current, which adopts the bipolar wide-range current detection system to detect the ion current of the ion pump;

[0045] The second end of R4 of the sampling resistor network is in communication with the shell of the ion pump, and the first end of R1 of the sampling resistor network is in communication with the positive electrode of the ion pump voltage source.

[0046] An ion pump ion current detection method, when the ion current is positive ion current, the ion pump ion current detection system is used for detection, the ion current flows from R4 to R1, and the differential signal is negative input at this time;

[0047] The method comprises the following steps:

[0048] S100, a first-stage ion current detection program is executed to determine whether an overcurrent alarm is triggered, which comprises sub-steps S101-S103;

[0049] S101, a multipath analog switch is set to read the voltage between R4, and the amplification multiple of a programmable gain amplifier is set to GAIN1, and the value AD collected by the differential analog-to-digital converter at this time is obtained;

[0050] S102, calculate ion current Icnt: Icnt= (65535-AD+1) x Vref / 32768 / GAIN1 / R4;

[0051] S103, logical judgment:

[0052] If Icnt is greater than ion current measurement threshold Icnt_MAX, overcurrent alarm is performed;

[0053] If Icnt is less than or equal to Icnt_MAX, turn to step S200;

[0054] S200, execute second-stage ion current detection procedure, which includes sub-steps S201-S203;

[0055] S201, set multi-path analog switch to read voltage across R4, set amplification factor of programmable gain amplifier to GAIN2, and obtain value AD collected by differential analog-to-digital converter at this time;

[0056] S202, calculate ion current Icnt: Icnt= (65535-AD+1) x Vref / 32768 / GAIN2 / R4;

[0057] S203, logical judgment:

[0058] If Icnt is greater than ion current measurement threshold Icnt_MAX, overcurrent alarm is performed, and return to step S100 to start detection again;

[0059] If Icnt is within [Icnt_MAX x 10 -1 , Icnt_MAX], return Icnt value as current ion current real-time value, end this detection, return to step S100 to start next detection;

[0060] If Icnt is less than Icnt_MAX x 10 -1 , turn to step S300;

[0061] S300, execute third-stage ion current detection procedure, which includes sub-steps S301-S303;

[0062] S301, set multi-path analog switch to read voltage across R4, set amplification factor of programmable gain amplifier to GAIN3, and obtain value AD collected by differential analog-to-digital converter at this time;

[0063] S302, calculate ion current Icnt: Icnt= (65535-AD+1) x Vref / 32768 / GAIN3 / R4;

[0064] S303, logical judgment:

[0065] If Icnt is greater than Icnt_MAX x 10 -1 , then return to step S200;

[0066] If Icnt is within the range of [Icnt_MAX x 10 -2 , Icnt_MAX x 10 -1 ], then return the value of Icnt as the current ion current real-time value, end this detection, and return to step S100 to start the next detection;

[0067] If Icnt is less than Icnt_MAX x 10 -2 , then turn to step S400;

[0068] S400, execute the fourth section of ion current detection program, which includes sub-steps S401-S403;

[0069] S401, set the multi-channel analog switch to read the voltage across R3, set the amplification factor of the programmable gain amplifier to GAIN3, and obtain the value AD collected by the differential analog-to-digital converter at this time;

[0070] S402, calculate the ion current Icnt: Icnt= (65535-AD+1) x Vref / 32768 / GAIN3 / R3;

[0071] S403, logical judgment:

[0072] If Icnt is greater than Icnt_MAX x 10 -2 , then return to step S300;

[0073] If Icnt is within the range of [Icnt_MAX x 10 -3 , Icnt_MAX x 10 -2 ], then return the value of Icnt as the current ion current real-time value, end this detection, and return to step S100 to start the next detection;

[0074] If Icnt is less than Icnt_MAX x 10 -3 , then turn to step S500;

[0075] S500, execute the fifth section of ion current detection program, which includes sub-steps S501-S503;

[0076] S501, set the multi-channel analog switch to read the voltage across R2, set the amplification factor of the programmable gain amplifier to GAIN2, and obtain the value AD collected by the differential analog-to-digital converter at this time;

[0077] S502, calculate ion current Icnt: Icnt= (65535-AD+1) x Vref / 32768 / GAIN2 / R2;

[0078] S503, logical judgment:

[0079] If Icnt is greater than Icnt_MAX x 10 -3 , return to step S400;

[0080] If Icnt is in the range of [Icnt_MAX x 10 -4 , Icnt_MAX x 10 -3 ], return the Icnt value as the current ion current real-time value, end this detection, and return to step S100 to start the next detection;

[0081] If Icnt is less than Icnt_MAX x 10 -4 , turn to step S600;

[0082] S600, execute the sixth section ion current detection program, which includes sub-steps S601-S603;

[0083] S601, set the multi-path analog switch to read the voltage across R2, set the amplification multiple of the programmable gain amplifier to GAIN3, and obtain the value AD collected by the differential analog-to-digital converter at this time;

[0084] S602, calculate ion current Icnt: Icnt= (65535-AD+1) x Vref / 32768 / GAIN3 / R2;

[0085] S603, logical judgment:

[0086] If Icnt is greater than Icnt_MAX x 10 -4 , return to step S500;

[0087] If Icnt is in the range of [Icnt_MAX x 10 -5 , Icnt_MAX x 10 -4 ], return the Icnt value as the current ion current real-time value, end this detection, and return to step S100 to start the next detection;

[0088] If Icnt is less than Icnt_MAX x 10 -5 , turn to step S700;

[0089] S700, execute the seventh section ion current detection program, which includes sub-steps S701-S703;

[0090] S701, the multi-path analog switch is set to read the voltage across R1, the programmable gain amplifier is set to have a gain of GAIN2, and the value AD collected by the differential analog-to-digital converter at this time is obtained;

[0091] S702, the ion current Icnt is calculated: Icnt= (65535-AD+1) x Vref / 32768 / GAIN2 / R1;

[0092] S703, logical judgment:

[0093] If Icnt is greater than Icnt_MAX x 10 -5 , then return to step S600;

[0094] If Icnt is within the range of [Icnt_MAX x 10 -6 , Icnt_MAX x 10 -5 ], then return the value of Icnt as the current ion current real-time value, end this detection, and return to step S100 to start the next detection;

[0095] If Icnt is less than Icnt_MAX x 10 -6 , then go to step S800;

[0096] S800, execute the eighth ion current detection program, which includes sub-steps S801-S803;

[0097] S801, the multi-path analog switch is set to read the voltage across R1, the programmable gain amplifier is set to have a gain of GAIN3, and the value AD collected by the differential analog-to-digital converter at this time is obtained;

[0098] S802, the ion current Icnt is calculated: Icnt= (65535-AD+1) x Vref / 32768 / GAIN3 / R1; return the value of Icnt as the current ion current real-time value, end this detection, and return to step S100 to start the next detection.

[0099] A method for detecting the ion current of an ion pump, when the ion current is a negative ion current, the ion pump ion current detection system described above is used to detect the ion current, the ion current flows from R1 to R4, and at this time the differential signal is a positive input;

[0100] The method comprises the following steps:

[0101] S100, execute the first ion current detection program, and judge whether to alarm for overcurrent, which includes sub-steps S101-S103;

[0102] S101, the multi-path analog switch is set to read the voltage across R4, the programmable gain amplifier is set to GAIN1, and the value AD collected by the differential analog-to-digital converter at this time is obtained;

[0103] S102, the ion current Icnt is calculated: Icnt = AD x Vref / 32768 / GAIN1 / R4;

[0104] S103, logical judgment:

[0105] If Icnt is greater than the ion current measurement threshold Icnt_MAX, overcurrent alarm is performed;

[0106] If Icnt is less than or equal to Icnt_MAX, step S200 is turned to;

[0107] S200, a second-stage ion current detection procedure is performed, which includes sub-steps S201-S203;

[0108] S201, the multi-path analog switch is set to read the voltage across R4, the programmable gain amplifier is set to GAIN2, and the value AD collected by the differential analog-to-digital converter at this time is obtained;

[0109] S202, the ion current Icnt is calculated: Icnt = AD x Vref / 32768 / GAIN2 / R4;

[0110] S203, logical judgment:

[0111] If Icnt is greater than the ion current measurement threshold Icnt_MAX, overcurrent alarm is performed, and the detection is restarted from step S100;

[0112] If Icnt is within the range [Icnt_MAX x 10 -1 , Icnt_MAX], the Icnt value is returned as the current ion current real-time value, the detection is ended, and the next detection is started from step S100;

[0113] If Icnt is less than Icnt_MAX x 10 -1 , step S300 is turned to;

[0114] S300, a third-stage ion current detection procedure is performed, which includes sub-steps S301-S303;

[0115] S301, the multi-path analog switch is set to read the voltage across R4, the programmable gain amplifier is set to GAIN3, and the value AD collected by the differential analog-to-digital converter at this time is obtained;

[0116] S302, calculate ion current Icnt: Icnt = AD x Vref / 32768 / GAIN3 / R4;

[0117] S303, logical judgment:

[0118] If Icnt is greater than Icnt_MAX x 10 -1 , return to step S200;

[0119] If Icnt is within [Icnt_MAX x 10 -2 , Icnt_MAX x 10 -1 ], return Icnt value as the current ion current real-time value, end this detection, return to step S100, start next detection;

[0120] If Icnt is less than Icnt_MAX x 10 -2 , turn to step S400;

[0121] S400, execute the fourth section ion current detection program, which includes sub-steps S401-S403;

[0122] S401, multi-path analog switch is set to read the voltage across R3, programmable gain amplifier is set to GAIN3, get the differential analog-to-digital converter collected value AD at this time;

[0123] S402, calculate ion current Icnt: Icnt = AD x Vref / 32768 / GAIN3 / R3;

[0124] S403, logical judgment:

[0125] If Icnt is greater than Icnt_MAX x 10 -2 , return to step S300;

[0126] If Icnt is within [Icnt_MAX x 10 -3 , Icnt_MAX x 10 -2 ], return Icnt value as the current ion current real-time value, end this detection, return to step S100, start next detection;

[0127] If Icnt is less than Icnt_MAX x 10 -3 , turn to step S500;

[0128] S500, execute the fifth section ion current detection program, which includes sub-steps S501-S503;

[0129] S501, the multipath analog switch is set to read the voltage across R2, the programmable gain amplifier is set to GAIN2, and the value AD collected by the differential analog-to-digital converter at this time is obtained;

[0130] S502, the ion current Icnt is calculated: Icnt = AD x Vref / 32768 / GAIN2 / R2;

[0131] S503, logical judgment:

[0132] If Icnt is greater than Icnt_MAX x 10 -3 , then return to step S400;

[0133] If Icnt is within [Icnt_MAX x 10 -4 , Icnt_MAX x 10 -3 ], then return the Icnt value as the current ion current real-time value, end this detection, and return to step S100 to start the next detection;

[0134] If Icnt is less than Icnt_MAX x 10 -4 , then go to step S600;

[0135] S600, execute the sixth segment ion current detection program, which includes sub-steps S601-S603;

[0136] S601, the multipath analog switch is set to read the voltage across R2, the programmable gain amplifier is set to GAIN3, and the value AD collected by the differential analog-to-digital converter at this time is obtained;

[0137] S602, the ion current Icnt is calculated: Icnt = AD x Vref / 32768 / GAIN3 / R2;

[0138] S603, logical judgment:

[0139] If Icnt is greater than Icnt_MAX x 10 -4 , then return to step S500;

[0140] If Icnt is within [Icnt_MAX x 10 -5 , Icnt_MAX x 10 -4 ], then return the Icnt value as the current ion current real-time value, end this detection, and return to step S100 to start the next detection;

[0141] If Icnt is less than Icnt_MAX x 10 -5 , then go to step S700;

[0142] S700, a seventh ion current detection procedure is executed, which includes sub-steps S701-S703;

[0143] S701, the multiplexing analog switch is set to read the voltage across R1, the programmable gain amplifier is set to have a gain of GAIN2, and the value AD collected by the differential analog-to-digital converter at this time is obtained;

[0144] S702, the ion current Icnt is calculated: Icnt=AD×Vref / 32768 / GAIN2 / R1;

[0145] S703, logical judgment:

[0146] If Icnt is greater than Icnt_MAX×10 -5 , then return to step S600;

[0147] If Icnt is within the range of [Icnt_MAX×10 -6 , Icnt_MAX×10 -5 ], then return the value of Icnt as the real-time value of the current ion current, end this detection, and return to step S100 to start the next detection;

[0148] If Icnt is less than Icnt_MAX×10 -6 , then go to step S800;

[0149] S800, an eighth ion current detection procedure is executed, which includes sub-steps S801-S803;

[0150] S801, the multiplexing analog switch is set to read the voltage across R1, the programmable gain amplifier is set to have a gain of GAIN3, and the value AD collected by the differential analog-to-digital converter at this time is obtained;

[0151] S802, the ion current Icnt is calculated: Icnt=AD×Vref / 32768 / GAIN3 / R1; return the value of Icnt as the real-time value of the current ion current, end this detection, and return to step S100 to start the next detection.

[0152] Further, Vref is the reference voltage of the differential analog-to-digital converter.

[0153] Further, R1=100R2, R2=100R3, and R3=10R4.

[0154] Further, R4=1 ohm, GAIN1=0.688, GAIN2=11, and GAIN3=88.

[0155] Further, Icnt_MAX is 0.2 A.

[0156] The application has the beneficial effects of:

[0157] First, the bipolar wide-range current detection system of the application realizes the following three functions:

[0158] a. Bipolar detection. The detection system of the application must be able to detect both positive and negative ion currents.

[0159] b. Wide-range detection. The detection system of the application can sample and convert the current signal in the range of 10 -1 A to 10 -10 A.

[0160] c. Removal of the zeroing circuit.

[0161] d. Suppression of common-mode signals and noise signals.

[0162] To solve the above problems, the application adopts a sampling resistor method differential amplification method, which is embodied in the following points:

[0163] 1.1. Design of the sampling resistor network. Specifically, it is embodied in that the sampling resistor network comprises: first resistor to fourth resistor R1 to R4, fifth resistor to ninth resistor R5 to R9 connected in series between the high-voltage network feedback end to GND; the two ends of R1 to R4 are both connected with forward electrode tube, reverse electrode tube and capacitor in parallel; the directions of the forward electrode tube and the reverse electrode tube are opposite; the second end of Ri is connected with the first end of Ri+1, i being any natural number from 1 to 3; the first end of R1 to R4 is connected with the first end of R5 to R8 respectively, and the second end of R4 is connected with the first end of R9; the second end of R5 to R9 is connected with the input end of the multi-channel analog switch.

[0164] 1.2. By collecting the voltage signal of the programmable gain amplifier, fixed impedance matching (setting of R12 and R13) is realized, which has a good inhibitory effect on common-mode signals (setting of C7 and C8), and the structure is simple and reliable. It can solve the detection of weak positive ion current and negative ion current under the same circuit model.

[0165] 1.3. The cooperative relationship of R1 to R4 and GAIN1 to GAIN3 Figure 6A specific example of R1~R4, GAIN1~GAIN3 of the present application is given. Through the setting of R1~R4, GAIN1~GAIN3, there are theoretically 12 combinations for the amplification of the signal. It is the key to realize wide range detection. For the detection of weak current, the existing design is often converted into an amplifier after I / V conversion. The sampling resistance network is generally only set with one sampling resistance, and the subsequent signal amplification mainly relies on the setting of the amplifier (in this case, the amplification range requirement of the second differential amplifier is wider, and multiple amplifiers are generally used). The design of the present application relative to the prior art can reduce the use of amplifiers and greatly reduce the cost.

[0166] Second, the design points of the ion pump ion current detection system of the present application are:

[0167] 2.1, using the aforementioned bipolar wide range current detection system.

[0168] 2.2, taking the measurement of positive ion current as an example. As shown in Figure 1 , the existing ion pump ion current detection system (i.e. the ammeter in Figure 1 ) is placed between the positive pole of the voltage source and the line between the anode cylinder 2.

[0169] The two ends of the sampling resistance network of the present application: one end is connected to GND (i.e. the pump wall of the ion pump), and the other end is connected to the negative pole of the ion pump voltage source. Compared with the ammeter in Figure 1 , the sampling resistance network of the present application is set in the low voltage area, which can reduce the damage of the ion pump ion current detection system when the current suddenly changes (the current direction is: the voltage source current passes through the ion pump to return to GND, and then passes through the sampling resistance network to return to the negative pole of the voltage source, forming a loop).

[0170] Taking the measurement of negative ion current as an example. As shown in Figure 2 , the two ends of the sampling resistance network of the present application: one end is connected to GND (i.e. the pump wall of the ion pump), and the other end is connected to the positive pole of the ion pump voltage source (the current direction is: R1 flows to R4). This setting avoids placing the bipolar wide range current detection system in the negative high voltage area.

[0171] That is, whether measuring positive ion current or negative ion current, the sampling resistance network is set with GND and the power supply pole connected to GND.

[0172] Third, the ion pump ion current calculation method is also a core difficulty.

[0173] 3.1, in the prior art, only the hardware structure of ion current detection is described, but no description is given for calculating the ion current.

[0174] 3.2, the present application adopts the order from large current to small current to select the appropriate sampling resistance and amplification multiple to make logical judgment, rather than the opposite order. Such detection order can timely perform overcurrent alarm.

[0175] 3.3, the measurement range of the present application is Icnt_MAX~Icnt_MAXx10 -9 . BRIEF DESCRIPTION OF DRAWINGS

[0176] The present application will be further described below in conjunction with the embodiments in the drawings, but does not constitute any limitation on the present application.

[0177] Figure 1 is a structural diagram of an ion pump of the prior art (positive ion flow).

[0178] Figure 2 is a structural diagram of an ion pump of the prior art (negative ion flow).

[0179] Figure 3 is a general architecture diagram of an ion pump ion flow detection system of the present application.

[0180] Figure 4 is a circuit design diagram of an ion pump ion flow detection system of the present application.

[0181] Figure 5 is a flow chart of a detection method of an ion pump ion flow of the present application.

[0182] Figure 6 is a specific example diagram of R1~R4, GAIN1~GAIN3 of the present application.

[0183] The reference signs are as follows:

[0184] Cathode TI shell 1, anode cylinder 2, pump wall 3;

[0185] Sampling resistance network 100, multi-channel analog switch 200, programmable gain amplifier 300, differential analog-to-digital converter 400, microprocessor 500. DETAILED DESCRIPTION

[0186] In order to make the purpose, technical scheme and advantages of the present application more clear, the technical scheme of the present application will be described clearly and completely below in conjunction with specific embodiments of the present application and corresponding drawings. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative labor fall within the scope of protection of the present application.

[0187] [Example One: an ion pump ion flow detection system]

[0188] Figure 3 The overall architecture of an ion pump ion current detection system is shown. Figure 4 The circuit design of an ion pump ion current detection system is shown.

[0189] From Figure 3 And Figure 4 It can be known that an ion pump ion current detection system comprises:

[0190] A, a sampling resistor network 100. The sampling resistor network 100 is used for converting a current signal into a voltage signal, that is, an I / V conversion circuit, clamping a maximum output voltage, protecting a subsequent circuit, and increasing a capacitor to filter common-mode signal noise.

[0191] B, a multipath analog switch 200: the microprocessor judges the current size through the values collected by the differential analog-to-digital converter and switches the output channel of the sampling resistor network 100.

[0192] C, a programmable gain amplifier 300: the microprocessor can adjust the gain effect of the programmable gain amplifier 300 according to the output channel of the I / V conversion circuit through the values collected by the differential analog-to-digital converter.

[0193] D, a differential analog-to-digital converter 400: analog-to-digital conversion is performed on the input differential signal.

[0194] E, a microprocessor 500, which is connected with the multipath analog switch 200, the programmable gain amplifier 300, and the differential analog-to-digital converter 400 respectively.

[0195] [Design of the sampling resistor network]

[0196] The sampling resistor network 100 comprises: a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a first forward electrode tube D1, a second reverse electrode tube D2, a third forward electrode tube D3, a fourth reverse electrode tube D4, a fifth forward electrode tube D5, a sixth reverse electrode tube D6, a seventh forward electrode tube D7, an eighth reverse electrode tube D8, a first capacitor C1, a second capacitor C2, a third capacitor C3, and a fourth capacitor C4.

[0197] R1, R2, R3, and R4 are connected in series, D1, D2, and C1 are connected in parallel at both ends of R1, D3, D4, and C2 are connected in parallel at both ends of R2, D5, D6, and C3 are connected in parallel at both ends of R3, and D7, D8, and C4 are connected in parallel at both ends of R4.

[0198] The first end of R1 is connected with the current line (for example, connected with the positive pole or negative pole of the voltage source when applied to the ion pump) and the first end of R5;

[0199] The first end of R2 is connected with the second end of R1 and the first end of R6;

[0200] The first end of R3 is connected with the second end of R2 and the first end of R7;

[0201] The first end of R4 is connected with the second end of R3 and the first end of R8;

[0202] The second end of R4 is connected with the current line (for example, connected with GND when applied to the ion pump) and the first end of R9;

[0203] It should be noted that the forward diode indicates the direction from the high-voltage network feedback end to the ground end, and the reverse diode indicates the direction from the ground end to the high-voltage network feedback end.

[0204] In the design of the present application, the relationship among R1, R2, R3 and R4 is R1=100R2, R2=100R3 and R3=10R4.

[0205] Suppose the ion current is Icnt; when the output is positive high voltage, the ion current returns from the ground to the high-voltage network feedback end, that is, the ion current flows from R4 to R1. When the ion pump system is suddenly exposed to the atmosphere to generate a large ion current, the voltage flowing through the resistance network rises, and when the voltage Icnt·R4 at both ends of R4 is greater than the conduction voltage of diode D8, the ion current is clamped through D8. When the voltage Icnt·R3 is greater than the conduction voltage of D6, the ion current is clamped through D6. When the voltage Icnt·R2 is greater than the conduction voltage of D4, the ion current is clamped through D4. When the voltage Icnt·R1 is greater than the conduction voltage of D2, the ion current is clamped through D2. That is, the multi-channel analog switch is protected by D2, D4, D6 and D8.

[0206] Similarly, when the output is negative high voltage, the ion current returns from the high-voltage network feedback end to the ground, that is, the ion current flows from R1 to R4. When the ion current rises, the voltage Icnt·R1 is greater than the conduction voltage of diode D1, and the ion current is clamped through D1.

[0207] The voltage Icnt·R2 is greater than the conduction voltage of diode D3, and the ion current is clamped through D3. The voltage Icnt·R3 is greater than the conduction voltage of diode D5, and the ion current is clamped through D5. The voltage Icnt·R4 is greater than the conduction voltage of diode D7, and the ion current is clamped through D7. That is, the multi-channel analog switch is protected by D1, D3, D5 and D7.

[0208] Table 1 Design of sampling resistance network

[0209]

[0210] Compared with the sampling resistance network of CN116221096A, the sampling resistance network of the present application has the following advantages:

[0211] (1) The sampling resistance network of the present application has five output channels to the multi-channel analog switch, which are respectively SGND, SIGNAL1, SIGNAL2, SIGNAL3 and EARTH. At different currents, different resistances are switched by the analog switch, corresponding to R1-R4, to generate different differential voltages, which are input into the differential amplifier.

[0212] If 4 lines or less are designed, each resistance ratio will be too large, and the amplification range of the second differential amplifier will be wider. If more resistance networks are selected, the multi-channel analog switch channel needs to be increased. With the above-mentioned ratio, a network of 4 resistances is appropriate.

[0213] (2) The filter capacitor is set in different ways. The filter capacitor of CN116221096A is a low-pass filter, which cannot filter out common-mode noise.

[0214] (3) The differential amplification circuit used in the present application has low gain or even completely eliminates the same voltage change (common-mode signal) on the non-inverting and inverting terminals. This means that the differential amplifier has strong suppression ability for noise or interference applied to both input terminals at the same time, thereby improving the signal-to-noise ratio and anti-interference performance. Compared with CN116221096A, the ion flow loop path is increased with the sampling resistance network, and the amplification multiple and complexity of the later-stage amplification circuit are reduced.

[0215] <Connection design of multi-channel analog switch>

[0216] The connection relationship between the multi-channel analog switch and the sampling resistance network, the microprocessor and the programmable gain amplifier is as follows: the second end of R5 is connected to the S1A pin of the multi-channel analog switch, the second end of R6 is connected to the S2A and S1B pins, the second end of R7 is connected to the S3A and S2B pins, the second end of R8 is connected to the S4A and S3B pins, and the second end of R9 is connected to the S4B pin. The EN pin of the multi-channel analog switch is connected to the PB0 pin of the microprocessor 500, the A0 pin is connected to the PB1 pin of the microprocessor, the A1 pin is connected to the PB2 pin of the microprocessor, and the DA and DB pins are connected to the programmable gain amplifier through resistors R10 and R11, respectively. At the same time, VDD, VEE and GND are connected to the system auxiliary power supply.

[0217] Table 2 Connection relationship of multi-channel analog switch

[0218]

[0219] Low level is denoted as 0, and high level is denoted as 1. The selection method of the multiplexing analog switch is as follows:

[0220] A1=1, A0=1: sampling the voltage between R4;

[0221] A1=1, A0=0: sampling the voltage between R3;

[0222] A1=0, A0=1: sampling the voltage between R2;

[0223] A1=0, A0=0: sampling the voltage between R1.

[0224] <Connection design of programmable gain amplifier>

[0225] The tenth resistor R10, the eleventh resistor R11 and the fifth capacitor C5 are arranged between the multiplexing analog switch and the programmable gain amplifier, and R10, R11 and C5 together constitute a first-order low-pass filter to suppress high-frequency noise. R10 and R11 are matching resistors, and generally take values of 1K~10K to reduce the error caused by the multiplexing analog switch.

[0226] The other ends of R10 and R11 are connected to the INP and INN pins of the programmable gain amplifier respectively after being connected in parallel with C5.

[0227] The G0 pin of the programmable gain amplifier is connected to the PB3 pin of the microprocessor, the G1 pin is connected to the PB4 pin of the microprocessor, the G2 pin is connected to the PB5 pin of the microprocessor, the G3 pin is connected to the PB6 pin of the microprocessor, the G4 pin is connected to the PB7 pin of the microprocessor, the EF pin is connected to the PB8 pin of the microprocessor, the VSP pin is connected to VDD of the auxiliary power supply, and the VSN pin is connected to VEE of the auxiliary power supply.

[0228] The DVDD pin and the VSOP pin are connected to VCC of the auxiliary power supply, the VCOM pin is connected to Vref1 (Vref1 is the common-mode voltage reference input of the programmable gain amplifier), and the VOP pin and the VON pin are connected to the first end of the twelfth resistor R12 and the first end of the thirteenth resistor R13.

[0229] Table 3 Connection relationship of programmable gain amplifier

[0230]

[0231] Low level is denoted as 0, and high level is denoted as 1. The amplification of the programmable gain amplifier PGA 281 has three cases: GAIN1 (0.688), GAIN2 (11), and GAIN3 (88).

[0232] When G3=0, G2=0, G1=1, and G0=0, the amplification is GAIN1.

[0233] When G3=0, G2=1, G1=1, and G0=0, the amplification is GAIN2.

[0234] When G3=1, G2=0, G1=0, and G0=1, the amplification is GAIN3.

[0235] <Connection design of differential analog-to-digital converter>

[0236] The twelfth resistor R12, the thirteenth resistor R13, the sixth capacitor C6, the seventh capacitor C7, and the eighth capacitor C8 are arranged between the programmable gain amplifier and the differential analog-to-digital converter. The resistors R12, R13, and C6 constitute a two-stage low-pass filter before analog-to-digital conversion, and high-frequency noise is suppressed, wherein R12 and R13 are matching resistors. C7 and C8 filter common-mode noise, and suppress common-mode signal interference such as power supply noise and ground loop interference.

[0237] The sixth capacitor C6 is connected between the second end of R12 and the second end of R13, the seventh capacitor C7 has its two ends connected to the second end of R13 and AGND, and the eighth capacitor C8 has its two ends connected to the second end of R12 and AGND.

[0238] The second end of R12 and the second end of R13 are connected to the IN+ and IN- pins of the differential analog-to-digital converter 400, the REFIN and +VA pins are connected to the reference voltage VREF, the GND pin is connected to AGND, the VBD pin is connected to the auxiliary power supply VCC, the SDI pin is connected to the PB9 pin of the microprocessor, the SCLK pin of U4 is connected to the PB10 pin of the microprocessor, the SDO pin is connected to the PB11 pin of the microprocessor, and the CONVST pin is connected to the PB12 pin of the microprocessor.

[0239] The differential analog-to-digital converter uses ADS8318. The reference voltage is Vref, and the sampling voltage range of the differential analog-to-digital converter is -Vref~Vref. Since the differential analog-to-digital converter is a 16-bit converter, when 0~(Vref-1LSB) is collected, the corresponding hexadecimal value is (0~0x7FFF), and the corresponding decimal value is (0~32767); when -Vref~(0-1LSB) is collected, the corresponding hexadecimal value is (0x8000~0xFFFF), and the corresponding decimal value is (32768~65535).

[0240] Table 4 Connection relationship of differential analog-to-digital converter

[0241]

[0242] Embodiment two: a method for detecting ion current of ion pump

[0243] A method for detecting ion current of ion pump, when the ion current is positive ion current (ion current flows from R4 to R1, at this time the differential signal is negative input);

[0244] The method comprises the following steps:

[0245] S100, execute the first section ion current detection program, judge whether to alarm overcurrent, which comprises sub-steps S101-S103;

[0246] S101, the multi-channel analog switch is set to read the voltage across R4, the amplification factor of the programmable gain amplifier is set to GAIN1, and the value AD collected by the differential analog-to-digital converter at this time is obtained;

[0247] Wherein, the voltage across R4 read by the multi-channel analog switch is controlled by microprocessor 500: microprocessor 500 gives the multi-channel analog switch instruction: A1=1 (i.e. the A1 pin of the multi-channel analog switch is high), A0=1 (i.e. the A0 pin of the multi-channel analog switch is high), at this time, S4A and S4B of the multi-channel analog switch are connected, and the voltage across R4 is read;

[0248] Wherein, the amplification factor of the programmable gain amplifier is controlled by microprocessor 500: G3=0 (the G3 pin of the programmable gain amplifier is low), G2=0 (the G2 pin of the programmable gain amplifier is low), G1=1 (the G1 pin of the programmable gain amplifier is high) G0=0 (the G0 pin of the programmable gain amplifier is low), at this time the amplification factor of the programmable gain amplifier is GAIN1;

[0249] S102, calculate ion current Icnt: Icnt= (65535-AD+1) x Vref / 32768 / GAIN1 / R4;

[0250] S103, logical judgment:

[0251] If Icnt is greater than ion current measurement threshold Icnt_MAX (Icnt_MAX represents the maximum value of product design current, exceeding which will affect the product components, so when the amplification factor is the lowest, if the current exceeds the design value, overcurrent alarm and stop output voltage);

[0252] If Icnt is less than or equal to Icnt_MAX, turn to step S200;

[0253] S200, a second-stage ion current detection procedure is performed, including sub-steps S201-S203;

[0254] S201, the multi-path analog switch is set to read the voltage across R4, the programmable gain amplifier is set to have a gain of GAIN2, and the value AD collected by the differential analog-to-digital converter at this time is obtained;

[0255] S202, the ion current Icnt is calculated: Icnt = (65535-AD+1) x Vref / 32768 / GAIN2 / R4;

[0256] S203, logical judgment:

[0257] If Icnt is greater than the ion current measurement threshold Icnt_MAX, an overcurrent alarm is performed, and the procedure returns to step S100 to restart detection;

[0258] If Icnt is within the range [Icnt_MAX x 10 -1 , Icnt_MAX], the value of Icnt is returned as the current ion current real-time value, the detection is ended, the procedure returns to step S100, and the next detection is started;

[0259] If Icnt is less than Icnt_MAX x 10 -1 , the procedure proceeds to step S300;

[0260] S300, a third-stage ion current detection procedure is performed, including sub-steps S301-S303;

[0261] S301, the multi-path analog switch is set to read the voltage across R4, the programmable gain amplifier is set to have a gain of GAIN3, and the value AD collected by the differential analog-to-digital converter at this time is obtained;

[0262] S302, the ion current Icnt is calculated: Icnt = (65535-AD+1) x Vref / 32768 / GAIN3 / R4;

[0263] S303, logical judgment:

[0264] If Icnt is greater than Icnt_MAX x 10 -1 , the procedure returns to step S200;

[0265] If Icnt is within the range [Icnt_MAX x 10 -2 , Icnt_MAX x 10 -1 ], the value of Icnt is returned as the current ion current real-time value, the detection is ended, the procedure returns to step S100, and the next detection is started;

[0266] If Icnt is less than Icnt_MAX x 10 -2 , then go to step S400;

[0267] S400, execute the fourth segment ion current detection procedure, which includes sub-steps S401-S403;

[0268] S401, the multi-channel analog switch is set to read the voltage across R3, the programmable gain amplifier is set to GAIN3, and the value AD collected by the differential analog-to-digital converter at this time is obtained;

[0269] S402, calculate the ion current Icnt: Icnt= (65535-AD+1) x Vref / 32768 / GAIN3 / R3;

[0270] S403, logical judgment:

[0271] If Icnt is greater than Icnt_MAX x 10 -2 , then return to step S300;

[0272] If Icnt is within [Icnt_MAX x 10 -3 , Icnt_MAX x 10 -2 ], then return the Icnt value as the current ion current real-time value, end this detection, and return to step S100 to start the next detection;

[0273] If Icnt is less than Icnt_MAX x 10 -3 , then go to step S500;

[0274] S500, execute the fifth segment ion current detection procedure, which includes sub-steps S501-S503;

[0275] S501, the multi-channel analog switch is set to read the voltage across R2, the programmable gain amplifier is set to GAIN2, and the value AD collected by the differential analog-to-digital converter at this time is obtained;

[0276] S502, calculate the ion current Icnt: Icnt= (65535-AD+1) x Vref / 32768 / GAIN2 / R2;

[0277] S503, logical judgment:

[0278] If Icnt is greater than Icnt_MAX x 10 -3 , then return to step S400;

[0279] If Icnt is within [Icnt_MAX x 10 -4 , Icnt_MAX x 10 -3If Icnt is greater than Icnt_MAXx10 -5 , then return to step S600;

[0280] If Icnt is less than Icnt_MAXx10 -5 , then turn to step S700; -4 -4 -5 -4 , then return the value of Icnt as the current ion current real-time value, end this detection, return to step S100, and start the next detection;

[0281] S600, execute the sixth ion current detection program, which includes sub-steps S601-S603;

[0282] S601, set the multi-path analog switch to read the voltage across R2, set the amplification factor of the programmable gain amplifier to GAIN3, and obtain the value AD collected by the differential analog-to-digital converter at this time;

[0283] S602, calculate the ion current Icnt: Icnt= (65535-AD+1) x Vref / 32768 / GAIN3 / R2;

[0284] S603, logical judgment:

[0285] If Icnt is greater than Icnt_MAXx10 -5 , then return to step S600;

[0286] If Icnt is within the range of [Icnt_MAXx10 -5 , Icnt_MAXx10 -4 ], then return the value of Icnt as the current ion current real-time value, end this detection, return to step S100, and start the next detection;

[0287] If Icnt is less than Icnt_MAXx10 -5 , then turn to step S700;

[0288] S700, execute the seventh ion current detection program, which includes sub-steps S701-S703;

[0289] S701, set the multi-path analog switch to read the voltage across R1, set the amplification factor of the programmable gain amplifier to GAIN2, and obtain the value AD collected by the differential analog-to-digital converter at this time;

[0290] S702, calculate the ion current Icnt: Icnt= (65535-AD+1) x Vref / 32768 / GAIN2 / R1;

[0291] S703, logical judgment:

[0292] If Icnt is greater than Icnt_MAXx10 -5 , then return to step S600;

[0293] If Icnt is in the range of [Icnt_MAX x 10 -6 , Icnt_MAX x 10 -5 , return the value of Icnt as the current ion current real-time value, end this detection, return to step S100, and start the next detection;

[0294] If Icnt is less than Icnt_MAX x 10 -6 , turn to step S800;

[0295] S800, execute the eighth segment ion current detection program, which includes sub-steps S801-S803;

[0296] S801, set the multi-path analog switch to read the voltage across R1, set the amplification factor of the programmable gain amplifier to GAIN3, and obtain the value AD collected by the differential analog-to-digital converter at this time;

[0297] S802, calculate the ion current Icnt: Icnt= (65535-AD+1) x Vref / 32768 / GAIN3 / R1; return the value of Icnt as the current ion current real-time value, end this detection, return to step S100, and start the next detection.

[0298] A method for detecting the ion current of an ion pump, when the ion current is a negative ion current (the ion current flows from R1 to R4, and the differential signal is positive input)

[0299] S100, execute the first segment ion current detection program, judge whether to alarm for overcurrent, which includes sub-steps S101-S103;

[0300] S101, set the multi-path analog switch to read the voltage across R4, set the amplification factor of the programmable gain amplifier to GAIN1, and obtain the value AD collected by the differential analog-to-digital converter at this time;

[0301] S102, calculate the ion current Icnt: Icnt=AD x Vref / 32768 / GAIN1 / R4;

[0302] S103, logical judgment:

[0303] If Icnt is greater than the ion current measurement threshold Icnt_MAX, alarm for overcurrent;

[0304] If Icnt is less than or equal to Icnt_MAX, turn to step S200;

[0305] S200, execute the second segment ion current detection program, which includes sub-steps S201-S203;

[0306] S201, the multipath analog switch is set to read the voltage across R4, the programmable gain amplifier is set to GAIN2, and the value AD collected by the differential analog-to-digital converter at this time is obtained;

[0307] S202, the ion current Icnt is calculated: Icnt = AD x Vref / 32768 / GAIN2 / R4;

[0308] S203, logical judgment:

[0309] If Icnt is greater than the ion current measurement threshold Icnt_MAX, overcurrent alarm is performed, and the step S100 is returned to start detection again;

[0310] If Icnt is in the range of [Icnt_MAX x 10 -1 , Icnt_MAX], the value of Icnt is returned as the current ion current real-time value, the detection is ended, the step S100 is returned, and the next detection is started;

[0311] If Icnt is less than Icnt_MAX x 10 -1 , the step S300 is turned to;

[0312] S300, the third ion current detection program is executed, which includes the sub-steps S301-S303;

[0313] S301, the multipath analog switch is set to read the voltage across R4, the programmable gain amplifier is set to GAIN3, and the value AD collected by the differential analog-to-digital converter at this time is obtained;

[0314] S302, the ion current Icnt is calculated: Icnt = AD x Vref / 32768 / GAIN3 / R4;

[0315] S303, logical judgment:

[0316] If Icnt is greater than Icnt_MAX x 10 -1 , the step S200 is returned;

[0317] If Icnt is in the range of [Icnt_MAX x 10 -2 , Icnt_MAX x 10 -1 ], the value of Icnt is returned as the current ion current real-time value, the detection is ended, the step S100 is returned, and the next detection is started;

[0318] If Icnt is less than Icnt_MAX x 10 -2 , the step S400 is turned to;

[0319] S400, execute the fourth segment ion current detection procedure, which includes sub-steps S401-S403;

[0320] S401, the multi-channel analog switch is set to read the voltage across R3, the programmable gain amplifier is set to GAIN3, and the value AD collected by the differential analog-to-digital converter at this time is obtained;

[0321] S402, calculate the ion current Icnt: Icnt = AD x Vref / 32768 / GAIN3 / R3;

[0322] S403, logical judgment:

[0323] If Icnt is greater than Icnt_MAX x 10 -2 , then return to step S300;

[0324] If Icnt is within [Icnt_MAX x 10 -3 , Icnt_MAX x 10 -2 ], then return the Icnt value as the current ion current real-time value, end this detection, and return to step S100 to start the next detection;

[0325] If Icnt is less than Icnt_MAX x 10 -3 , then go to step S500;

[0326] S500, execute the fifth segment ion current detection procedure, which includes sub-steps S501-S503;

[0327] S501, the multi-channel analog switch is set to read the voltage across R2, the programmable gain amplifier is set to GAIN2, and the value AD collected by the differential analog-to-digital converter at this time is obtained;

[0328] S502, calculate the ion current Icnt: Icnt = AD x Vref / 32768 / GAIN2 / R2;

[0329] S503, logical judgment:

[0330] If Icnt is greater than Icnt_MAX x 10 -3 , then return to step S400;

[0331] If Icnt is within [Icnt_MAX x 10 -4 , Icnt_MAX x 10 -3 ], then return the Icnt value as the current ion current real-time value, end this detection, and return to step S100 to start the next detection;

[0332] If Icnt is less than Icnt_MAX x 10-4 If yes, go to step S600;

[0333] S600, execute the sixth ion current detection procedure, which includes sub-steps S601-S603;

[0334] S601, set the multi-path analog switch to read the voltage across R2, set the amplification factor of the programmable gain amplifier to GAIN3, and obtain the value AD collected by the differential analog-to-digital converter at this time;

[0335] S602, calculate the ion current Icnt: Icnt = AD x Vref / 32768 / GAIN3 / R2;

[0336] S603, logical judgment:

[0337] If Icnt is greater than Icnt_MAX x 10 -4 , return to step S500;

[0338] If Icnt is within the range of [Icnt_MAX x 10 -5 , Icnt_MAX x 10 -4 ], return the value of Icnt as the real-time value of the current ion current, end this detection, and return to step S100 to start the next detection;

[0339] If Icnt is less than Icnt_MAX x 10 -5 , go to step S700;

[0340] S700, execute the seventh ion current detection procedure, which includes sub-steps S701-S703;

[0341] S701, set the multi-path analog switch to read the voltage across R1, set the amplification factor of the programmable gain amplifier to GAIN2, and obtain the value AD collected by the differential analog-to-digital converter at this time;

[0342] S702, calculate the ion current Icnt: Icnt = AD x Vref / 32768 / GAIN2 / R1;

[0343] S703, logical judgment:

[0344] If Icnt is greater than Icnt_MAX x 10 -5 , return to step S600;

[0345] If Icnt is within the range of [Icnt_MAX x 10 -6 , Icnt_MAX x 10 -5 ], return the value of Icnt as the real-time value of the current ion current, end this detection, and return to step S100 to start the next detection;

[0346] If Icnt is less than Icnt_MAX x 10 -6 , then go to step S800;

[0347] S800, execute the eighth paragraph ion current detection program, which includes sub-steps S801-S803;

[0348] S801, the multi-path analog switch is set to read the voltage across R1, the programmable gain amplifier is set to GAIN3, and the value AD collected by the differential analog-to-digital converter at this time is obtained;

[0349] S802, calculate the ion current Icnt: Icnt=ADxVref / 32768 / GAIN3 / R1; return the Icnt value as the current ion current real-time value, end this detection, and return to step S100 to start the next detection.

[0350] It should be noted that R1-R4 mentioned in the Icnt calculation formula in the method for detecting the ion current of an ion pump refer to the resistance values.

[0351] It should be noted that Vref mentioned in the Icnt calculation formula in the method for detecting the ion current of an ion pump refers to the reference voltage of the differential analog-to-digital converter.

[0352] It should be noted that: Figure 6 in the formula, " / " indicates that the resistance value or the amplification multiple is not used in this step.

[0353] The above-mentioned embodiments are the preferred embodiments of the present application, which are only used to facilitate the description of the present application and do not limit the present application in any form. Any person skilled in the art can make equivalent embodiments by making partial changes or modifications to the disclosed technical content within the scope of the technical features of the present application without departing from the technical features of the present application, and such equivalent embodiments still belong to the scope of the technical features of the present application.

Claims

1. A bipolar wide-range current sensing system, characterized by, The application relates to a current signal acquisition device, which comprises the following parts: a, a sampling resistance network for collecting current signals and converting the current signals into voltage signals; the sampling resistance network comprises first resistance to fourth resistance R1 to R4, fifth resistance to ninth resistance R5 to R9 connected in series between external current loops; a forward electrode tube, a reverse electrode tube and a capacitor are connected in parallel to both ends of R1 to R4; the direction of the forward electrode tube is opposite to that of the reverse electrode tube; the second end of Ri is connected with the first end of Ri+1, and i is any natural number from 1 to 3; the first end of R1 to R4 is connected with the first end of R5 to R8 respectively, and the second end of R4 is connected with the first end of R9; the second end of R5 to R9 is connected with the input end of a multi-channel analog switch; b, the multi-channel analog switch is connected with multiple output channels of the sampling resistance network and can switch the output channels of the sampling resistance network; c, a programmable gain amplifier is used for adjusting the amplification multiple of signals transmitted by the multi-channel analog switch; d, a differential analog-digital converter is used for converting analog signals into digital signals; e, a microprocessor is bidirectionally connected with the multi-channel analog switch, the programmable gain amplifier and the differential analog-digital converter; the microprocessor can send control instructions to the multi-channel analog switch to switch the output channels of the sampling resistance network and send control instructions to the programmable gain amplifier to adjust the gain effect of the programmable gain amplifier according to the values collected by the differential analog-digital converter; wherein a first-order low-pass filter is arranged between the multi-channel analog switch and the programmable gain amplifier; wherein a second-order low-pass filter is arranged between the programmable gain amplifier and the differential analog-digital converter. The multi-channel analog switch adopts ADG1209 which contains S1A-S4A pins and S1B-S4B pins; the second end of R5 is connected to the S1A pin; the second end of R6 is connected to the S2A and S1B pins; the second end of R7 is connected to the S3A and S2B pins; the second end of R8 is connected to the S4A and S3B pins; and the second end of R9 is connected to the S4B pin. The multi-channel analog switch adopts ADG1209 which contains DA and DB pins; the programmable gain amplifier adopts PGA281 which contains INP and INN pins; the first-order low-pass filter is composed of a tenth resistance R10, an eleventh resistance R11 and a fifth capacitor C5; the first end of R10 is connected with the DA pin and the second end of R10 is connected with the INP pin; the first end of R10 is connected with the DB pin and the second end of R10 is connected with the INN pin; and the second end of R10 and the second end of R11 are connected with C5. The programmable gain amplifier adopts PGA281 which contains VOP and VON pins; the differential analog-digital converter adopts ADS8318 which contains IN+ and IN- pins; the second-order low-pass filter is composed of a twelfth resistance R12, a thirteenth resistance R13 and a sixth capacitor C6; the first end of R12 is connected with the VOP pin and the second end of R12 is connected with the IN+ pin; the first end of R13 is connected with the VON pin and the second end of R13 is connected with the IN- pin. ​ ​ ​ ​ 2. A bipolar wide-range current sensing system according to claim 1, wherein, ​ ​ ​ ​ ​ ​ 3. The bipolar wide-range current sensing system of claim 1, wherein, ​ ​ ​ ​ ​ ​ 4. The bipolar wide-range current sensing system of claim 1, wherein, ​ ​ ​ ​ ​ C6 is connected between the second end of R12 and the second end of R13.

5. A bipolar wide-range current sensing system according to claim 4, wherein, Further comprising: a seventh capacitor C7, an eighth capacitor C8; C7 is arranged between the second end of R13 and AGND, C7 is arranged between the second end of R12 and AGND.

6. An ion pump ion current detection system, the ion current being a positive ion current, characterized by, The ion flow of the ion pump is detected by using the bipolar wide-range current detection system according to any one of claims 1 to 5. The second end of R4 of the sampling resistance network is in communication with the shell of the ion pump, and the first end of R1 of the sampling resistance network is in communication with the negative electrode of the voltage source of the ion pump.

7. An ion pump ion current detection system, the ion current being a negative ion current, characterized by, The ion flow of the ion pump is detected by using the bipolar wide-range current detection system according to any one of claims 1 to 5. The second end of R4 of the sampling resistance network is in communication with the shell of the ion pump, and the first end of R1 of the sampling resistance network is in communication with the positive electrode of the voltage source of the ion pump.

8. A method for detecting the ion flow of an ion pump by using the ion flow detection system of the ion pump according to claim 6, wherein when the ion flow is a positive ion flow, the ion flow flows from R4 to R1. characterized in that The method comprises the following steps: S100, a first-stage ion flow detection program is executed to determine whether to alarm for overcurrent, which comprises sub-steps S101-S103; S101, the multi-path analog switch is set to read the voltage between R4, the amplification multiple of the programmable gain amplifier is set to GAIN1, and the value AD collected by the differential analog-to-digital converter at this time is obtained; S102, the ion flow Icnt is calculated: Icnt= (65535-AD+1) x Vref / 32768 / GAIN1 / R4; S103, logical judgment: If Icnt is greater than the ion flow measurement threshold Icnt_MAX, overcurrent alarm is performed; If Icnt is less than or equal to Icnt_MAX, the step S200 is turned to; S200, a second-stage ion flow detection program is executed, which comprises sub-steps S201-S203; S201, the multi-path analog switch is set to read the voltage between R4, the amplification multiple of the programmable gain amplifier is set to GAIN2, and the value AD collected by the differential analog-to-digital converter at this time is obtained; S202, the ion flow Icnt is calculated: Icnt= (65535-AD+1) x Vref / 32768 / GAIN2 / R4; S203, logical judgment: If Icnt is greater than the ion flow measurement threshold Icnt_MAX, overcurrent alarm is performed, and the step S100 is returned to start detection again; If Icnt is in the range of [Icnt_MAX x 10 -1 , Icnt_MAX], the value of Icnt is returned as the current ion current real-time value, the detection is ended, and the step S100 is returned to start the next detection. If Icnt is less than Icnt_MAX x 10 -1 then go to step S300; S300, a third-stage ion flow detection program is executed, which comprises sub-steps S301-S303; S301, the multi-path analog switch is set to read the voltage between R4, the amplification multiple of the programmable gain amplifier is set to GAIN3, and the value AD collected by the differential analog-to-digital converter at this time is obtained; S302, the ion flow Icnt is calculated: Icnt= (65535-AD+1) x Vref / 32768 / GAIN3 / R4; S303, logical judgment: If Icnt is greater than Icnt_MAX x 10 -1 then return to step S200; If Icnt is in [Icnt_MAX×10] -2 Icnt_MAX×10 -1 If the current ion flow rate is within the specified range, the Icnt value is returned as the current real-time ion flow rate value, the current detection ends, and the process returns to step S100 to start the next detection. If Icnt is less than Icnt_MAX x 10 -2 then go to step S400; S400, a fourth-stage ion flow detection program is executed, which comprises sub-steps S401-S403; S401, the multi-path analog switch is set to read the voltage across R3, the programmable gain amplifier is set to GAIN3, and the value AD collected by the differential analog-to-digital converter at this time is obtained; S402, the ion current Icnt is calculated: Icnt=(65535-AD+1)×Vref / 32768 / GAIN3 / R3; S403, logical judgment: If Icnt is greater than Icnt_MAX x 10 -2 then return to step S300; If Icnt is in the range of [Icnt_MAX x 10 -3 , Icnt_MAX x 10 -2 ], the value of Icnt is returned as the current ion current real-time value, the detection is ended, and the step S100 is returned to start the next detection. If Icnt is less than Icnt_MAX x 10 -3 then go to step S500; S500, the fifth segment ion current detection program is executed, which includes sub-steps S501-S503; S501, the multi-path analog switch is set to read the voltage across R2, the programmable gain amplifier is set to GAIN2, and the value AD collected by the differential analog-to-digital converter at this time is obtained; S502, the ion current Icnt is calculated: Icnt=(65535-AD+1)×Vref / 32768 / GAIN2 / R2; S503, logical judgment: If Icnt is greater than Icnt_MAX x 10 -3 then return to step S400; If Icnt is in [Icnt_MAX×10] -4 Icnt_MAX×10 -3 If the current ion flow rate is within the specified range, the Icnt value is returned as the current real-time ion flow rate value, the current detection ends, and the process returns to step S100 to start the next detection. If Icnt is less than Icnt_MAX x 10 -4 then go to step S600; S600, the sixth segment ion current detection program is executed, which includes sub-steps S601-S603; S601, the multi-path analog switch is set to read the voltage across R2, the programmable gain amplifier is set to GAIN3, and the value AD collected by the differential analog-to-digital converter at this time is obtained; S602, the ion current Icnt is calculated: Icnt=(65535-AD+1)×Vref / 32768 / GAIN3 / R2; S603, logical judgment: If Icnt is greater than Icnt_MAX x 10 -4 then return to step S500; If Icnt is in [Icnt_MAX×10] -5 Icnt_MAX×10 -4 If the current ion flow rate is within the specified range, the Icnt value is returned as the current real-time ion flow rate value, the current detection ends, and the process returns to step S100 to start the next detection. If Icnt is less than Icnt_MAX x 10 -5 then go to step S700; S700, the seventh segment ion current detection program is executed, which includes sub-steps S701-S703; S701, the multi-path analog switch is set to read the voltage across R1, the programmable gain amplifier is set to GAIN2, and the value AD collected by the differential analog-to-digital converter at this time is obtained; S702, the ion current Icnt is calculated: Icnt=(65535-AD+1)×Vref / 32768 / GAIN2 / R1; S703, logical judgment: If Icnt is greater than Icnt_MAX x 10 -5 then return to step S600; If Icnt is in [Icnt_MAX×10] -6 Icnt_MAX×10 -5 If the current ion current is within the range of ], the Icnt value is returned as the current real-time value of the ion current, the current detection ends, and the process returns to step S100 to start the next detection. If Icnt is less than Icnt_MAX x 10 -6 then go to step S800; S800, the eighth segment ion current detection program is executed, which includes sub-steps S801-S803; S801, the multi-path analog switch is set to read the voltage across R1, the programmable gain amplifier is set to GAIN3, and the value AD collected by the differential analog-to-digital converter at this time is obtained; S802, the ion current Icnt is calculated: Icnt=(65535-AD+1)×Vref / 32768 / GAIN3 / R1; The Icnt value is returned as the current ion current real-time value, the detection is ended, and the next detection is started from step S100; The Vref is the reference voltage of the differential analog-to-digital converter.

9. An ion pump ion current detection method, which uses the ion pump ion current detection system of claim 7 to detect the ion current, and when the ion current is a negative ion current, the ion current flows from R1 to R4; characterized in that Including the following steps: S100, a first segment ion current detection program is executed to determine whether to alarm for overcurrent, which includes sub-steps S101-S103; S101, the multi-path analog switch is set to read the voltage across R4, the programmable gain amplifier is set to GAIN1, and the value AD collected by the differential analog-to-digital converter at this time is obtained; S102, the ion current Icnt is calculated: Icnt = AD × Vref / 32768 / GAIN1 / R4; S103, logical judgment: If Icnt is greater than the ion current measurement threshold Icnt_MAX, overcurrent alarm is performed; If Icnt is less than or equal to Icnt_MAX, turn to step S200; S200, a second section of ion current detection program is executed, which includes sub-steps S201-S203; S201, the multi-path analog switch is set to read the voltage across R4, the programmable gain amplifier is set to GAIN2, and the value AD collected by the differential analog-to-digital converter at this time is obtained; S202, the ion current Icnt is calculated: Icnt = AD × Vref / 32768 / GAIN2 / R4; S203, logical judgment: If Icnt is greater than the ion current measurement threshold Icnt_MAX, overcurrent alarm is performed, and the detection is restarted from step S100; If Icnt is within the range of [Icnt_MAX x 10 -1 , Icnt_MAX], the value of Icnt is returned as the current ion current real-time value, the detection is ended, and the process returns to step S100 to start the next detection. If Icnt is less than Icnt_MAX x 10 -1 then go to step S300; S300, a third section of ion current detection program is executed, which includes sub-steps S301-S303; S301, the multi-path analog switch is set to read the voltage across R4, the programmable gain amplifier is set to GAIN3, and the value AD collected by the differential analog-to-digital converter at this time is obtained; S302, the ion current Icnt is calculated: Icnt = AD × Vref / 32768 / GAIN3 / R4; S303, logical judgment: If Icnt is greater than Icnt_MAX x 10 -1 then return to step S200; If Icnt is in [Icnt_MAX×10] -2 Icnt_MAX×10 -1 If the current ion current is within the range of ], the Icnt value is returned as the current real-time value of the ion current, the current detection ends, and the process returns to step S100 to start the next detection. If Icnt is less than Icnt_MAX x 10 -2 then go to step S400; S400, a fourth section of ion current detection program is executed, which includes sub-steps S401-S403; S401, the multi-path analog switch is set to read the voltage across R3, the programmable gain amplifier is set to GAIN3, and the value AD collected by the differential analog-to-digital converter at this time is obtained; S402, the ion current Icnt is calculated: Icnt = AD × Vref / 32768 / GAIN3 / R3; S403, logical judgment: If Icnt is greater than Icnt_MAX x 10 -2 then return to step S300; If Icnt is in [Icnt_MAX×10] -3 Icnt_MAX×10 -2 If the current ion current is within the range of ], the Icnt value is returned as the current real-time value of the ion current, the current detection ends, and the process returns to step S100 to start the next detection. If Icnt is less than Icnt_MAX x 10 -3 then go to step S500; S500, a fifth section of ion current detection program is executed, which includes sub-steps S501-S503; S501, the multi-path analog switch is set to read the voltage across R2, the programmable gain amplifier is set to GAIN2, and the value AD collected by the differential analog-to-digital converter at this time is obtained; S502, the ion current Icnt is calculated: Icnt = AD × Vref / 32768 / GAIN2 / R2; S503, logical judgment: If Icnt is greater than Icnt_MAX x 10 -3 then return to step S400; If Icnt is in [Icnt_MAX×10] -4 Icnt_MAX×10 -3 If the current ion current is within the range of ], the Icnt value is returned as the current real-time value of the ion current, the current detection ends, and the process returns to step S100 to start the next detection. If Icnt is less than Icnt_MAX x 10 -4 then go to step S600; S600, a sixth section of ion current detection program is executed, which includes sub-steps S601-S603; S601, the multi-path analog switch is set to read the voltage across R2, the programmable gain amplifier is set to GAIN3, and the value AD collected by the differential analog-to-digital converter at this time is obtained; S602, the ion current Icnt is calculated: Icnt = AD × Vref / 32768 / GAIN3 / R2; S603, logical judgment: If Icnt is greater than Icnt_MAX x 10 -4 then return to step S500; If Icnt is in the range of [Icnt_MAX x 10 -5 , Icnt_MAX x 10 -4 ], the Icnt value is returned as the current ion current real-time value, the detection is ended, and the step S100 is returned to start the next detection. If Icnt is in the range of [Icnt_MAX x 10 -5 , Icnt_MAX x 10 -4 ], the Icnt value is returned as the current ion current real-time value, the detection is ended, and If Icnt is less than Icnt_MAX x 10 -5 then go to step S700; S700, execute the seventh paragraph ion flow detection procedure, including sub-steps S701-S703; S701, the multi-channel analog switch is set to read the voltage across R1, the programmable gain amplifier is set to GAIN2, and the value AD collected by the differential analog-to-digital converter at this time is obtained; S702, calculate the ion flow Icnt: Icnt=AD×Vref / 32768 / GAIN2 / R1; S703, logical judgment: If Icnt is greater than Icnt_MAX x 10 -5 then return to step S600; If Icnt is in [Icnt_MAX×10] -6 Icnt_MAX×10 -5 If the current ion current is within the range of ], the Icnt value is returned as the current real-time value of the ion current, the current detection ends, and the process returns to step S100 to start the next detection. If Icnt is less than Icnt_MAX x 10 -6 then go to step S800; S800, execute the eighth paragraph ion flow detection procedure, including sub-steps S801-S803; S801, the multi-channel analog switch is set to read the voltage across R1, the programmable gain amplifier is set to GAIN3, and the value AD collected by the differential analog-to-digital converter at this time is obtained; S802, calculate the ion flow Icnt: Icnt=AD×Vref / 32768 / GAIN3 / R1; return the Icnt value as the current ion flow real-time value, end this detection, and return to step S100 to start the next detection; The Vref is the reference voltage of the differential analog-to-digital converter.

10. A method of detecting ion current in an ion pump according to claim 8 or 9, characterized in that, R1=100R2, R2=100R3, R3=10R4, R4=1Ω.

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