A cold cathode ionization gauge driving and collecting circuit

Abstract

The application discloses a cold cathode ionization gauge driving and collecting circuit, and relates to the field of vacuum measurement, which solves the problems of signal conversion nonlinearity and excessive ion current when the gauge tube works at a lower vacuum degree in the existing cold cathode ionization gauge driving and collecting technology, and comprises the following parts: an ion current logarithmic collecting circuit, which is used for converting the ion current of the cold cathode ionization gauge into a voltage signal; a current monitoring circuit, which is used for generating a control signal according to the voltage signal; a voltage-controlled high-voltage driving circuit, which is used for driving the cold cathode ionization gauge according to the control signal; a nonlinear compensation operation conditioning circuit, which is used for performing nonlinear compensation on the voltage signal according to the control signal to obtain an operation collecting voltage; and the operation collecting voltage is used for inputting into a collecting system; the problem of signal conversion nonlinearity is overcome through the nonlinear compensation circuit, and the negative feedback loop control is performed through the current monitoring circuit and the voltage-controlled high-voltage driving circuit, so that the driving voltage of the gauge tube is reduced, and the maximum ion current is limited at a lower level.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of vacuum measurement, more particularly, it relates to a cold cathode ionization gauge driving acquisition circuit. BACKGROUND

[0002] In the principle of a typical cold cathode ionization gauge, due to the initial ionization caused by cosmic rays and field emission, after the gauge tube is started, under the action of electric field and magnetic field, the electrons are limited in a spiral path, so that they have a longer path length and a higher possibility of ionizing the residual gas. When the vacuum degree is high, the discharge ion current and the vacuum degree have a positive linear correspondence relationship, and the gas pressure can be determined by collecting the discharge ion current. Considering the principle and structure of the cold cathode ionization gauge, the following problems exist in the existing cold cathode ionization gauge driving acquisition technology:

[0003] When the vacuum degree is low (the pressure is greater than about 2x10 -3 Pa), due to the decrease of the equivalent resistance of the discharge space, the increase of the ion current gradually slows down, causing the signal to correspond to the nonlinearity of the vacuum degree. And after the pressure is greater than about 5x10 -2 Pa, due to excessive reduction of the equivalent resistance, the discharge ion current is critically saturated, and the current changes sharply, which has a higher requirement on the resolution of the acquisition circuit, increasing the acquisition cost. At the same time, since the cold cathode ionization gauge works in a continuous discharge state, an oxide layer will be formed on the surface of the cathode and the anode after long-term use, and the gauge can only be restored to normal measurement after cleaning and maintenance. The severity of oxidation is positively correlated with the size of the discharge ion current. In the existing circuit, the size of the ion current is limited by a series current-limiting resistor, but the size of the current-limiting resistor should not be too large to limit the sensitivity at high vacuum degree, which causes the ion current to be too large when the gauge tube works at a low vacuum degree, and the maintenance frequency is high after long-term work, which limits the effective use time.

[0004] Therefore, the present application provides a cold cathode ionization gauge driving acquisition circuit to solve the above problems. SUMMARY

[0005] The purpose of the present application is to provide a cold cathode ionization gauge driving acquisition circuit to solve the problems of signal conversion nonlinearity and ion current being too large when the gauge tube works at a low vacuum degree in the existing cold cathode ionization gauge driving acquisition technology. The present application overcomes the problem of signal conversion nonlinearity through a nonlinear compensation circuit, and reduces the driving voltage of the gauge tube through a current monitoring circuit and a voltage-controlled high-voltage driving circuit for negative feedback loop control, limiting the maximum ion current to a lower level.

[0006] The above technical purpose of the application is achieved by the following technical scheme: comprising: an ion current logarithmic acquisition circuit, a current monitoring circuit, a voltage-controlled high-voltage driving circuit, and a nonlinear compensation operation conditioning circuit; the ion current logarithmic acquisition circuit is used to convert the ion current of the cold cathode ion gauge into a voltage signal, the current monitoring circuit is used to generate a control signal according to the voltage signal, the voltage-controlled high-voltage driving circuit is used to drive the cold cathode ion gauge according to the control signal, and the nonlinear compensation operation conditioning circuit is used to perform nonlinear compensation on the voltage signal according to the control signal to obtain an operation acquisition voltage, and the operation acquisition voltage is used to input a collection system.

[0007] In a possible implementation, the ion current logarithmic acquisition circuit comprises: operational amplifiers U1 and U2, matched triodes Q1A and Q1D, a terminal J1, a reference voltage source, a potentiometer VR1, capacitors C1, C2, C3, C5, C6, C7, a filter capacitor C4, resistors R1, R2, R3, R4, R6, a current-limiting resistor R5, and a thermistor PTC1; the terminal J1 is connected to an ion current signal, and after being filtered by the filter capacitor C4 and the current-limiting resistor R5, is connected to the inverting input terminal of the operational amplifier U1 and the collector of the triode Q1D, respectively; the noninverting input terminal of the operational amplifier U1 is grounded; the positive and negative power supply terminals of the operational amplifier U1 are connected to the positive and negative power supplies and filtered by the capacitors C5 and C6; the output terminal of the operational amplifier U1 outputs a converted voltage signal; the output terminal is divided by the resistor R6, the potentiometer VR1, and the thermistor PTC1, and then added to the base of the triode Q1A; the output terminal is also connected to the collector of the triode Q1D through the capacitor C7; the base of the triode Q1D is grounded; and the emitters of the triode Q1D and the triode Q1A are connected; the reference voltage source is connected to the noninverting input terminal and the inverting input terminal of the operational amplifier U2 through the resistors R1, R2, and R4; the positive and negative power supply terminals of the operational amplifier U2 are connected to the positive and negative power supplies and filtered by the capacitors C2 and C3; the output terminal of the operational amplifier U2 is connected to the emitters of the triode Q1D and the triode Q1A through the resistor R3; and the output terminal of the operational amplifier U2 is connected to the inverting input terminal of itself and the collector of the triode Q1A through the capacitor C1.

[0008] In a possible implementation, the size of the voltage signal is determined by the resistor R6, the potentiometer VR1, the thermistor PTC1, the Boltzmann constant , the absolute temperature , the electronic charge , the ion current signal, and the fixed current flowing through the collector of the triode Q1A.

[0009] In a possible implementation, the current monitoring circuit comprises: an operational amplifier U3A, an operational amplifier U3B, a diode D5, a diode D6, a resistor R14, a resistor R15, a resistor R17, a pull-down resistor R16, a capacitor C9, a capacitor C10, a capacitor C11, and a capacitor C12; a voltage signal output by the ion current logarithmic acquisition circuit is connected to the inverting input terminal of the operational amplifier U3A through the resistor R15, the inverting input terminal of the operational amplifier U3A is connected to the output terminal thereof through a filter circuit composed of the resistor R14 and the capacitor C10, the diode D5, and the capacitor C9, the non-inverting input terminal of the operational amplifier U3A is grounded through the resistor R17, the output terminal of the operational amplifier U3A is connected to the non-inverting output terminal of the operational amplifier U3B through the diode D6, the non-inverting input terminal of the operational amplifier U3B is also grounded through the resistor R16, the inverting output terminal of the operational amplifier U3B is connected to the output terminal thereof, the positive and negative power supply terminals of the operational amplifier U3B are connected to the positive and negative power supply and grounded through the capacitor C11 and the capacitor C12, and the output terminal of the operational amplifier U3B outputs a control signal.

[0010] In a possible implementation, the cathode of the diode D5 is connected to the inverting input terminal of the operational amplifier U3A, and the anode thereof is connected to the output terminal of the operational amplifier U3A; the cathode of the diode D6 is connected to the output terminal of the operational amplifier U3A, and the anode thereof is connected to the non-inverting output terminal of the operational amplifier U3B.

[0011] In a possible implementation, the voltage-controlled high-voltage driving circuit comprises: a voltage regulating circuit, a Royer push-pull self-oscillation circuit, and a voltage doubling rectifier circuit; the voltage regulating circuit outputs a direct-current voltage according to the control signal output by the current monitoring circuit; the Royer push-pull self-oscillation circuit inverts the direct-current voltage and outputs alternating-current high voltage through a transformer; and the voltage doubling rectifier circuit adjusts the alternating-current high voltage into direct-current high voltage and outputs the same.

[0012] In a possible implementation, the voltage regulating circuit comprises: an adjustable voltage stabilizer U4, a potentiometer VR2, a resistor R22, a resistor R18, a capacitor C13, a control signal output by the current monitoring circuit is connected to the adjusting end of the adjustable voltage stabilizer U4 through the potentiometer VR2 and the resistor R22 and the resistor R18, the input end of the adjustable voltage stabilizer U4 is connected to the power supply and filtered through the capacitor C13, the output end of the adjustable voltage stabilizer U4 outputs a direct current voltage, and the output end is connected to the connection point of the resistor R22 and the resistor R18; the Royer push-pull self-oscillation circuit comprises: a resistor R23, an electrolytic capacitor C15, an electrolytic capacitor C19, a resistor R19, a resistor R24, a capacitor C20, a capacitor C14, a capacitor C17, a triode Q1, a triode Q2, and a transformer T1, the transformer comprises: a first transformer primary side, a second transformer primary side, and a transformer secondary side, the direct current voltage output by the adjustable voltage stabilizer U4 is connected to the center tap of the first transformer primary side through the electrolytic capacitor C15 and grounded, the direct current voltage output by the adjustable voltage stabilizer U4 is connected to the center tap of the second transformer primary side through the resistor R23, the capacitor C20, and the electrolytic capacitor C19, the opposite end of the first transformer primary side is connected to the same end of the second transformer primary side through the triode Q1 and the resistor R19, the same end of the first transformer primary side is connected to the opposite end of the second transformer primary side through the triode Q2 and the resistor R24, the collector of the triode Q1 is connected to the base of the triode Q1 through the capacitor C14, the collector of the triode Q2 is connected to the base of the triode Q2 through the capacitor C17, the emitter of the triode Q1 and the emitter of the triode Q2 are connected to the ground, and the transformer secondary side outputs an alternating current high voltage; the voltage doubling rectifier circuit comprises: a high-voltage capacitor C16, a high-voltage capacitor C18, a high-voltage diode D1, and a high-voltage diode D2, the alternating current high voltage output by the transformer secondary side is connected to the high-voltage capacitor C16 in series and then connected to the high-voltage diode D1 in parallel, the high-voltage diode D2 is connected to the high-voltage diode D1 in series and then connected to the high-voltage capacitor C18 in parallel, the high-voltage capacitor C18 is connected to a load resistor R25 in parallel, and one end of the load resistor R25 is connected to a current-limiting resistor R20 and a current-limiting resistor R21, and a direct current high voltage is output.

[0013] In a possible implementation, the nonlinear compensation operation conditioning circuit includes: an operational amplifier U2B, an operational amplifier U2A, a diode D7, a diode D8, a diode D9, a resistor R25, a resistor R26, a resistor R27, a resistor R28, a resistor R29, a resistor R30, a resistor R31, a resistor R32, a resistor R33, a resistor R34, a resistor R35, a resistor R36, a capacitor C20, a capacitor C21, and a capacitor C22. The output of the ion current logarithmic acquisition circuit is connected to the inverting input terminal of the operational amplifier U2B through the resistor R35, the noninverting input terminal of the operational amplifier U2B is connected to the ground through the resistor R36, the positive and negative power supply terminals of the operational amplifier U2B are connected to the positive and negative power supply and filtered through the capacitor C22 and the capacitor C21, the output of the operational amplifier U2B is connected to the inverting input terminal of the operational amplifier U2B through the resistor R33, the resistor R33 is connected in parallel with the capacitor C20, the capacitor C20 is connected in parallel with the diode D9, the cathode of the diode D9 is connected to the reference voltage source through the resistor R31, and the output of the operational amplifier U2B is connected to the inverting input terminal of the operational amplifier U2A through the resistor R34. The control signal is connected to the inverting input terminal of the operational amplifier U2A through the nonlinear compensation branch, the inverting input terminal of the operational amplifier U2A is connected to the output terminal of the operational amplifier U2A through the resistor R27 and the diode D7 connected in parallel, the noninverting input terminal of the operational amplifier U2A is connected to the ground through the resistor R32, and the output terminal of the operational amplifier U2A outputs an operation acquisition voltage for inputting into the acquisition system.

[0014] In a possible implementation, the nonlinear compensation branch includes: a reference voltage source, a resistor R25, a resistor R28, a diode D8, a resistor R26, a resistor R29, a resistor R30, and a potentiometer VR3. The reference voltage source is connected to the inverting input terminal of the operational amplifier U2A through the resistor R25, the resistor R28, the resistor R29, and the resistor R30. The connection point of the resistor R28 and the resistor R29 is connected to the control signal output by the current monitoring circuit. The connection point of the resistor R25 and the resistor R28 is connected to the inverting input terminal of the operational amplifier U2A through the diode D8, the resistor R26, and the potentiometer VR3.

[0015] In a possible implementation, when the ion current signal is smaller than the threshold value, the control signal voltage output by the current monitoring circuit is maintained at 0 V. At this time, only the signal output by the operational amplifier U2B enters the operational amplifier U2A, and the voltage output by the operational amplifier U2A is: , The output voltage of the operational amplifier U2B is related to the size of the ion current. When the circuit enters the constant current mode through the negative feedback loop formed by the current monitoring circuit and the voltage-controlled high-voltage driving circuit, the voltage signal output by the ion current logarithmic acquisition circuit will be maintained at 0 V, The output fixed value participates in the addition operation, and the control signal voltage output by the current monitoring circuit is​ From 0V to the negative voltage direction changes, before the diode D8 is turned on, only resistance R29, resistance R30 participates in the feedback operation, at this time the voltage output by the operational amplifier U2A is: , the control signal voltage After the diode D8 is turned on, resistance R26, potentiometer VR3 also participate in the feedback operation, at this time the voltage output by the operational amplifier U2A is: , wherein The on voltage drop of diode D7 is The voltage applied to the cathode of diode D7.

[0016] Compared with the prior art, the present application has the following beneficial effects: by introducing a nonlinear compensation circuit, the nonlinear problem in the signal conversion process is effectively solved; at the same time, a negative feedback loop is constructed by using a current monitoring circuit and a voltage-controlled high-voltage driving circuit, the driving voltage of the cold cathode ionization gauge is reduced, and the maximum ion current is limited to a lower level; the cold cathode ionization gauge driving and collecting circuit provided by the present application can significantly reduce the collection difficulty, maintenance frequency and power consumption of the driving circuit of the cold cathode ionization gauge, while improving the reliability, measurement accuracy and upper limit of measurement. BRIEF DESCRIPTION OF DRAWINGS

[0017] The accompanying drawings, which are included to provide a further understanding of the embodiments of the present application and constitute a part of the application, do not constitute a limitation to the embodiments of the present application. In the drawings:

[0018] Figure 1 The cold cathode ionization gauge driving and collecting circuit provided by the present application is shown in the circuit principle diagram;

[0019] Figure 2 The ion current logarithmic collecting circuit provided by the present application is shown in the circuit diagram;

[0020] Figure 3 The current monitoring circuit provided by the present application is shown in the circuit diagram;

[0021] Figure 4 The voltage-controlled high-voltage driving circuit provided by the present application is shown in the circuit diagram;

[0022] Figure 5 The nonlinear compensation operation conditioning circuit provided by the present application is shown in the circuit diagram. DETAILED DESCRIPTION

[0023] Hereinafter, the term "include" or "may include" used in various embodiments of the present application indicates existence of a certain function, operation, or element, and does not limit one or more functions, operations, or elements to be added. Also, as used in various embodiments of the present application, the term "include" or "have" and variations thereof are intended to mean that specific features, numbers, steps, operations, elements, components, or combinations thereof are present, and should not be construed as limiting one or more features, numbers, steps, operations, elements, components, or combinations thereof from being added.

[0024] It should be noted that if a first constituent element is "connected" to or "connected with" a second constituent element, the first constituent element can be directly connected to the second constituent element, and a third constituent element can be "connected" between the first constituent element and the second constituent element. Conversely, when a first constituent element is "directly connected" to or "directly connected with" a second constituent element, it can be understood that there is no third constituent element between the first constituent element and the second constituent element.

[0025] The terms used in various embodiments of the present application are used only to describe specific embodiments and are not intended to limit various embodiments of the present application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Unless defined otherwise, all terms used herein (including technical terms and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which various embodiments of the present application belong. The terms such as those defined in a generally used dictionary will be interpreted to have the same meaning as the contextual meaning in the relevant related art and will not be interpreted to have ideal or excessively formal meanings, unless clearly defined in various embodiments of the present application.

[0026] In order to make the purposes, technical solutions, and advantages of the present application more clear, further specific description will be given to the present application with reference to the embodiments and the accompanying drawings, and the schematic embodiments of the present application and the description thereof are only used to explain the present application, and do not limit the present application.

[0027] Please refer to Figure 1 as shown, Figure 1The circuit principle diagram of the cold cathode ion gauge driving acquisition circuit provided by the embodiment of the application is provided. The cold cathode ion gauge driving acquisition circuit comprises an ion current logarithmic acquisition circuit, a current monitoring circuit, a voltage-controlled high-voltage driving circuit and a nonlinear compensation operation conditioning circuit. The ion current logarithmic acquisition circuit is used for converting the ion current of the cold cathode ion gauge into a voltage signal. The current monitoring circuit is used for generating a control signal according to the voltage signal. The voltage-controlled high-voltage driving circuit is used for driving the cold cathode ion gauge according to the control signal. The nonlinear compensation operation conditioning circuit is used for performing nonlinear compensation on the voltage signal according to the control signal to obtain an operation acquisition voltage. The operation acquisition voltage is used for inputting into an acquisition system.

[0028] The improvement of the application is that the nonlinear problem in the ion current signal conversion process of the ion gauge is effectively solved by introducing the nonlinear compensation circuit. Meanwhile, the negative feedback loop is constructed by using the current monitoring circuit and the voltage-controlled high-voltage driving circuit, the driving voltage of the cold cathode ion gauge is reduced, and the maximum ion current is limited at a lower level. The cold cathode ion gauge driving acquisition circuit provided by the application can significantly reduce the acquisition difficulty, maintenance frequency and power consumption of the driving circuit of the cold cathode ion gauge, and improve the reliability, measurement accuracy and upper limit of measurement.

[0029] Please refer to Figure 2 as shown, Figure 2The circuit diagram of the ion current logarithmic acquisition circuit provided by the embodiment of the present application is shown in the figure. In a possible implementation, the ion current logarithmic acquisition circuit comprises: operational amplifiers U1 and U2, matched triodes Q1A and Q1D, a terminal J1, a reference voltage source, a potentiometer VR1, capacitors C1, C2, C3, C5, C6, C7, a filter capacitor C4, resistors R1, R2, R3, R4, R6, a current-limiting resistor R5, and a thermistor PTC1. The terminal J1 is connected to an ion current signal, and after being filtered by the filter capacitor C4 and the current-limiting resistor R5, the ion current signal is connected to the inverting input terminal of the operational amplifier U1 and the collector of the triode Q1D, respectively. The non-inverting input terminal of the operational amplifier U1 is grounded, and the positive and negative power supply terminals of the operational amplifier U1 are connected to the positive and negative power supplies and filtered by the capacitors C5 and C6. The output terminal of the operational amplifier U1 outputs a converted voltage signal, and the output terminal is divided by the resistor R6, the potentiometer VR1, and the thermistor PTC1 and then applied to the base of the triode Q1A. The output terminal is also connected to the collector of the triode Q1D through the capacitor C7. The base of the triode Q1D is grounded, and the emitters of the triodes Q1D and Q1A are connected.

[0030] Further, the size of the voltage signal is determined by the resistor R6, the potentiometer VR1, the thermistor PTC1, the Boltzmann constant , the absolute temperature , the electronic charge , the ion current signal, and the fixed current flowing through the collector of the triode Q1A.

[0031] Specifically, the ion current logarithmic acquisition circuit is a logarithmic amplification circuit with differential proportional operation, and the converted voltage signal Log_Out is output through the output terminal of the operational amplifier U1. After the operational amplifier U1 and the operational amplifier U2 establish deep negative feedback, the output is divided by the resistor R6, the potentiometer VR1, and the thermistor PTC1 and then applied to the base of the triode Q1A. At this time, the voltage at the base of Q1A is: , wherein represents the voltage signal output by the ion current logarithmic acquisition circuit; under the action of the -5V reference voltage source and the resistors R1, R2, and R4, the collector of the triode Q1A will flow a fixed current, and the current value is: When the resistance R1, the resistance R2 is 47.5kΩ, the resistance R4 is 2.49kΩ, is 100uA. At this time according to the Shockley diode equation, the base to emitter voltage of the transistor Q1A is: where is Boltzmann constant, is the electron charge, is the absolute temperature, is the reverse saturation current of the transistor Q1A, which is affected by temperature. At the same time, the ion current signal Current_Signal input from the terminal J1 flows through the collector of the transistor Q1D after being filtered by the capacitor C4 and limited by the resistor R5, at this time the base to emitter voltage of the transistor Q1D is: where is the ion current signal, the direction is outflow, is the reverse saturation current of the transistor Q1D, because the selected transistor Q1A and the transistor Q1D are matched transistors, it can be considered that . Since the base of the transistor Q1D is ground potential, and the emitter of the transistor Q1A and the transistor Q1D is equipotential, the relationship is: is the base voltage of the transistor Q1A, and then: The thermistor PTC1 selects a 1kΩ, 3500PPM positive temperature coefficient thermistor, which can basically offset the temperature effect, at this time the observation expression, because the rest of the parameters are constant, the output will only be proportional to the logarithm of the input ion current, the output slope can be changed by adjusting the voltage divider ratio of the potentiometer VR1. The operational amplifier U1 can use OPA928DR, and the operational amplifier U2 can use OP07. The positive and negative power supplies are +15V and -15V power supplies.

[0032] Please refer to Figure 3 , Figure 3 ​The circuit diagram of the current monitoring circuit provided by the embodiment of the present application is shown in the figure. In a possible implementation, the current monitoring circuit comprises: an operational amplifier U3A, an operational amplifier U3B, a diode D5, a diode D6, a resistor R14, a resistor R15, a resistor R17, a pull-down resistor R16, a capacitor C9, a capacitor C10, a capacitor C11, and a capacitor C12. The voltage signal output by the ion current logarithmic acquisition circuit is connected to the inverting input terminal of the operational amplifier U3A through the resistor R15, the inverting input terminal of the operational amplifier U3A is connected to the output terminal thereof through a filter circuit composed of the resistor R14 and the capacitor C10, the diode D5, and the capacitor C9, the non-inverting input terminal of the operational amplifier U3A is grounded through the resistor R17, the output terminal of the operational amplifier U3A is connected to the non-inverting output terminal of the operational amplifier U3B through the diode D6, the non-inverting input terminal of the operational amplifier U3B is also grounded through the resistor R16, the inverting output terminal of the operational amplifier U3B is connected to the output terminal thereof, and the positive and negative power supply terminals of the operational amplifier U3B are connected to the positive and negative power supply and grounded through the capacitor C11 and the capacitor C12. The output terminal of the operational amplifier U3B outputs a control signal.

[0033] Further, the cathode of the diode D5 is connected to the inverting input terminal of the operational amplifier U3A, and the anode thereof is connected to the output terminal of the operational amplifier U3A; the cathode of the diode D6 is connected to the output terminal of the operational amplifier U3A, and the anode thereof is connected to the non-inverting output terminal of the operational amplifier U3B.

[0034] Specifically, the current monitoring circuit is mainly an amplification circuit with zero-crossing response, and the input of the circuit is the output Log_Out of the ion current logarithmic acquisition circuit. As can be known from the output formula of the ion current logarithmic acquisition circuit, when the ion current signal is less than 100uA, the input value of the circuit is negative, the diode D5 will be turned on, and the output of the operational amplifier U3A is maintained at the conduction voltage of the diode D5. The voltage on the negative electrode of the diode D6 is greater than that on the positive electrode, and the diode D6 cannot be turned on. The non-inverting input terminal of the operational amplifier U3B will be maintained at a low level under the action of the pull-down resistor R16, and a 0V voltage is output through the voltage follower circuit composed of the operational amplifier U3B. When the ion current signal is greater than 100uA, the input value of the circuit is positive at this time. Due to the open-loop gain of the operational amplifier U3A, the operational amplifier U3A will quickly output a negative voltage and make the diode D6 conductive. Then a negative voltage is output through the voltage follower, until the output reaches the negative power supply voltage -15V. The control signal HV_Adj output by the circuit is used as the input of the voltage-controlled high-voltage driving circuit, and a negative feedback loop is formed. The operational amplifier U3A and the operational amplifier U3B can be LM258, and the diode D5 and the diode D6 can be MMBD914LT3G.

[0035] Please refer to Figure 4 as shown, Figure 4The circuit diagram of the voltage-controlled high-voltage driving circuit provided by the embodiment of the present application is shown in the figure. In a possible implementation, the voltage-controlled high-voltage driving circuit comprises a voltage regulating circuit, a Royer push-pull self-oscillation circuit and a voltage doubling rectifier circuit. The voltage regulating circuit outputs a direct current voltage according to a control signal output by a current monitoring circuit. The Royer push-pull self-oscillation circuit inverts the direct current voltage and outputs an alternating current high voltage through a transformer. The voltage doubling rectifier circuit adjusts the alternating current high voltage to a direct current high voltage and outputs the direct current high voltage.

[0036] Further, the voltage regulating circuit comprises an adjustable voltage stabilizer U4, a potentiometer VR2, a resistor R22, a resistor R18 and a capacitor C13. The control signal output by the current monitoring circuit is connected to the adjusting end of the adjustable voltage stabilizer U4 through the potentiometer VR2 and the resistor R22 and the resistor R18. The input end of the adjustable voltage stabilizer U4 is connected to a power supply and filtered through the capacitor C13. The output end of the adjustable voltage stabilizer U4 outputs a direct current voltage. The output end is connected to the connection point of the resistor R22 and the resistor R18. The Royer push-pull self-oscillation circuit comprises a resistor R23, an electrolytic capacitor C15, an electrolytic capacitor C19, a resistor R19, a resistor R24, a capacitor C20, a capacitor C14, a capacitor C17, a triode Q1, a triode Q2 and a transformer T1. The transformer comprises a first transformer primary winding, a second transformer primary winding and a transformer secondary winding. The direct current voltage output by the adjustable voltage stabilizer U4 is connected to the center tap of the first transformer primary winding through the electrolytic capacitor C15. The direct current voltage output by the adjustable voltage stabilizer U4 is connected to the center tap of the second transformer primary winding through the resistor R23, the capacitor C20 and the electrolytic capacitor C19. The opposite end of the first transformer primary winding is connected to the same end of the second transformer primary winding through the triode Q1 and the resistor R19. The same end of the first transformer primary winding is connected to the opposite end of the second transformer primary winding through the triode Q2 and the resistor R24. The collector of the triode Q1 is connected to the base of the triode Q1 through the capacitor C14. The collector of the triode Q2 is connected to the base of the triode Q2 through the capacitor C17. The emitter of the triode Q1 and the emitter of the triode Q2 are connected to the ground. The transformer secondary winding outputs an alternating current high voltage. The voltage doubling rectifier circuit comprises a high-voltage capacitor C16, a high-voltage capacitor C18, a high-voltage diode D1 and a high-voltage diode D2. The alternating current high voltage output by the transformer secondary winding is connected in series with the high-voltage capacitor C16 and connected in parallel with the high-voltage diode D1. The high-voltage diode D2 is connected in series with the high-voltage diode D1 and connected in parallel with the high-voltage capacitor C18. The high-voltage capacitor C18 is connected in parallel with a load resistor R25. One end of the load resistor R25 is connected to the ground through the current-limiting resistor R20 and the current-limiting resistor R21. The direct current high voltage is output.

[0037] Specifically, the voltage-controlled high-voltage driving circuit for driving the cold cathode ionization gauge is mainly composed of a typical Royer push-pull self-oscillation circuit, a voltage doubler rectifier circuit and a voltage regulating circuit. The Royer circuit principle is to realize the push-pull self-oscillation of the circuit by the current saturation of the triode and the auxiliary winding of the transformer magnetic core saturation, and then to output high voltage after the input DC voltage is inverted through the transformer. The output voltage of the secondary side of the transformer is mainly determined by the input DC voltage and the turns ratio of the transformer. The output voltage is output as DC high voltage after passing through the voltage doubler rectifier circuit composed of high-voltage capacitor C16, high-voltage capacitor C18, high-voltage diode D1 and high-voltage diode D2, and is used to drive the cold cathode pin of the cold cathode ionization gauge. The resistor R25 in the rear stage is used as a load resistor, and the resistors R20 and R21 are used as current limiting resistors. The input DC voltage of the transformer is output by the voltage regulating circuit composed of the adjustable voltage stabilizer U4. The adjustable voltage stabilizer U4 can be LM317T, and the output voltage of the voltage regulating circuit is obtained from the chip manual as follows: , The voltage value of the control signal HV_Adj output by the current monitoring circuit can be seen as follows: since the resistors R1, R5 and the potentiometer VR1 are constant values, the output voltage of the voltage regulating circuit is only determined by the output of the current monitoring circuit. When the current monitoring circuit monitors that the ion current signal is greater than 100uA, the negative feedback loop will adjust the size of the output high voltage, so that the ion current signal remains at about 100uA, thereby realizing the current limiting protection function. The triodes Q1 and Q2 can be CXT3019, the transformer T1 can be Trans-RM10, and the diodes D1 and D2 can be HV5.

[0038] Please refer to Figure 5 as shown, Figure 5The circuit diagram of the nonlinear compensation operation conditioning circuit provided by the embodiment of the present application is shown in the figure. In a possible implementation, the nonlinear compensation operation conditioning circuit comprises: an operational amplifier U2B, an operational amplifier U2A, a diode D7, a diode D8, a diode D9, a resistor R25, a resistor R26, a resistor R27, a resistor R28, a resistor R29, a resistor R30, a resistor R31, a resistor R32, a resistor R33, a resistor R34, a resistor R35, a resistor R36, a capacitor C20, a capacitor C21, and a capacitor C22. The output of the ion current logarithmic acquisition circuit is connected to the inverting input terminal of the operational amplifier U2B through the resistor R35, the noninverting input terminal of the operational amplifier U2B is connected to the ground through the resistor R36, the positive and negative power supply terminals of the operational amplifier U2B are connected to the positive and negative power supply and filtered through the capacitor C22 and the capacitor C21, the output of the operational amplifier U2B is connected to the inverting input terminal of the operational amplifier U2B through the resistor R33, the resistor R33 is connected in parallel with the capacitor C20, the capacitor C20 is connected in parallel with the diode D9, the cathode of the diode D9 is connected to the reference voltage source through the resistor R31, and the output of the operational amplifier U2B is connected to the inverting input terminal of the operational amplifier U2A through the resistor R34. The control signal is connected to the inverting input terminal of the operational amplifier U2A through the nonlinear compensation branch, the inverting input terminal of the operational amplifier U2A is connected to the output terminal of the operational amplifier U2A through the resistor R27 and the diode D7 connected in parallel, the noninverting input terminal of the operational amplifier U2A is connected to the ground through the resistor R32, and the output terminal of the operational amplifier U2A outputs the operation acquisition voltage for inputting into the acquisition system.

[0039] Further, the nonlinear compensation branch comprises: a reference voltage source, the resistor R25, the resistor R28, the diode D8, the resistor R26, the resistor R29, the resistor R30, and a potentiometer VR3. The reference voltage source is connected to the inverting input terminal of the operational amplifier U2A through the resistor R25, the resistor R28, the resistor R29, and the resistor R30. The connection point of the resistor R28 and the resistor R29 is connected to the control signal output by the current monitoring circuit. The connection point of the resistor R25 and the resistor R28 is connected to the inverting input terminal of the operational amplifier U2A through the diode D8, the resistor R26, and the potentiometer VR3.

[0040] Further, when the ion current signal is smaller than the threshold value, the control signal voltage output by the current monitoring circuit is maintained at 0V. At this time, only the signal output by the operational amplifier U2B enters the operational amplifier U2A, and the voltage output by the operational amplifier U2A is: , The output voltage of the operational amplifier U2B is related to the size of the ion current. When the circuit enters the constant current mode through the negative feedback loop formed by the current monitoring circuit and the voltage-controlled high-voltage driving circuit, the voltage signal output by the ion current logarithmic acquisition circuit will be maintained at 0V, ​The output fixed value participates in the addition operation, and the control signal voltage output by the current monitoring circuit From 0V to negative voltage direction, before the diode D8 is turned on, only the resistance R29 and the resistance R30 participate in the feedback operation, at this time the voltage output by the operational amplifier U2A is: , the control signal voltage After the diode D8 is turned on, the resistance R26 and the potentiometer VR3 also participate in the feedback operation, at this time the voltage output by the operational amplifier U2A is: , wherein is the turn-on voltage drop of the diode D7, is the voltage applied to the cathode of the diode D7.

[0041] Specifically, the nonlinear compensation operation conditioning circuit body is composed of two-stage reverse addition proportional operation circuits, and the latter stage is followed by an output voltage clamping and ADC collected voltage clamping protection circuit. The first-stage reverse addition proportional operation circuit composed of the operational amplifier U2B reversely adds and proportionally amplifies the voltage signal Log_Out output by the ion flow logarithmic acquisition circuit and the 5V reference voltage source, and the output voltage of the operational amplifier U2B is: , After passing through the feedback resistance R34, it enters the second-stage reverse addition proportional operation circuit composed of the operational amplifier U2A. In addition to the branch, the second-stage proportional operation circuit also has a nonlinear compensation branch composed of the 5V reference voltage source, the resistance R25, the resistance R28, the diode D8, the resistance R26, the resistance R29, the resistance R30, and the potentiometer VR3. The input of the nonlinear compensation branch is the control signal HV_Adj output by the current monitoring circuit. As can be seen from the analysis of the input signal and the circuit structure, when the input ion flow signal is less than 100uA (threshold), the control signal voltage output by the current monitoring circuit will be maintained at 0V, at this time only the signal of the branch actually participates in the second-stage operation, that is, at this time the output voltage is only related to the ion flow size. At this time, the output voltage of the operational amplifier U2A is: When the circuit enters the constant current mode through the negative feedback loop composed of the current monitoring circuit and the voltage-controlled high-voltage driving circuit, the output voltage of the ion flow logarithmic acquisition circuit will be maintained at 0V and will no longer change, a fixed value will be output to participate in the addition operation, at this time the output voltage is irrelevant to the ion flow size, but only related to the control signal. The nonlinear compensation branch realizes nonlinear compensation through the voltage division circuit composed of the 5V reference voltage source, the resistance R25, and the resistance R28, and the diode D8, the feedback resistance R26, and the potentiometer VR3. The specific process is as follows: when the circuit enters the constant current mode, the control signal voltage From 0V to the negative voltage direction change, the voltage added on the cathode of diode D7 is: The anode voltage of diode D7 is 0V before conduction, only resistance R29 and resistance R30 participate in feedback operation before the voltage divider circuit makes diode D7 conductive, at this time the output of the circuit is: When the control signal voltage makes diode D7 conductive, resistance R26 and potentiometer VR3 also start to participate in feedback operation, at this time the output of the circuit is: Wherein is the conduction voltage drop of diode D7, it can be seen from the formula that the conduction of diode D7 increases the feedback coefficient of the nonlinear compensation branch, by setting the values of resistance R25 and resistance R28, the opening time of nonlinear compensation can be controlled, and by potentiometer VR3, the proportion of nonlinear compensation can be set, thereby completing the nonlinear compensation of the signal. After the compensation of the circuit, the operation collection voltage ColdCathode ANL OUT enters the collection system, realizing the driving collection of the cold cathode ionization gauge. Operational amplifier U2B and operational amplifier U2A can use LM258.

[0042] It can be understood that when the circuit enters the constant current mode, the control signal voltage starts from 0V to the negative voltage direction, the reason is that the current monitoring circuit is an amplification circuit with zero-crossing response, because the ion current is greater than 100uA, the output of the logarithmic collection circuit (i.e. the input of the current monitoring circuit) will cross from negative value to positive value, according to the output characteristics of the current monitoring circuit, the response result will start from 0V to the negative voltage direction.

[0043] The above specific embodiments further illustrate the purpose, technical solutions and beneficial effects of the present application, it should be understood that the above description is only a specific embodiment of the present application, and is not used to limit the protection scope of the present application, any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A cold cathode ionization gauge drive acquisition circuit, comprising: The application relates to a cold cathode ionization gauge control system, which comprises an ion current logarithmic acquisition circuit, a current monitoring circuit, a voltage-controlled high-voltage driving circuit and a nonlinear compensation operation conditioning circuit. The ion current logarithmic acquisition circuit is used for converting the ion current of a cold cathode ionization gauge into a voltage signal, the current monitoring circuit is used for generating a control signal according to the voltage signal, the voltage-controlled high-voltage driving circuit is used for driving the cold cathode ionization gauge according to the control signal, and the nonlinear compensation operation conditioning circuit is used for performing nonlinear compensation on the voltage signal according to the control signal to obtain an operation acquisition voltage, which is used for inputting into a collection system. The nonlinear compensation operation conditioning circuit comprises an operational amplifier U2B, an operational amplifier U2A, diodes D7, D8 and D9, resistors R25, R26, R27, R28, R29, R30, R31, R32, R33, R34, R35 and R36, and capacitors C20, C21 and C22; the output of the ion current logarithmic acquisition circuit is connected with the inverting input end of the operational amplifier U2B through the resistor R35, the noninverting input end of the operational amplifier U2B is connected with the ground through the resistor R36, the positive and negative power supply ends of the operational amplifier U2B are connected with the positive and negative power supply and are filtered through the capacitors C22 and C21, the output of the operational amplifier U2B is connected with the inverting input end of itself through the resistor R33, the resistor R33 is connected with the capacitor C20 in parallel, the capacitor C20 is connected with the diode D9 in parallel, the cathode of the diode D9 is connected with a reference voltage source through the resistor R31, and the output of the operational amplifier U2B is connected with the inverting input end of the operational amplifier U2A through the resistor R34. The control signal is connected with the inverting input end of the operational amplifier U2A through a nonlinear compensation branch, the inverting input end of the operational amplifier U2A is connected with the output end of itself through the parallel-connected resistor R27 and diode D7, the noninverting input end of the operational amplifier U2A is connected with the ground through the resistor R32, and the output end of the operational amplifier U2A outputs the operation acquisition voltage for inputting into the collection system. The ion current logarithmic acquisition circuit comprises operational amplifiers U1 and U2, matched triodes Q1A and Q1D, a terminal J1, a reference voltage source, a potentiometer VR1, capacitors C1, C2, C3, C5, C6, C7 and C4, and resistors R1, R2, R3, R4, R6 and R5 and a current-limiting resistor PTC1.

2. A cold cathode ion gauge drive pick-up circuit according to claim 1, characterised in that, ​ The terminal J1 accesses the ion flow signal, connects the inverting input terminal of the operational amplifier U1 and the collector of the transistor Q1D after filtering capacitor C4 and current limiting resistor R5, the non-inverting input terminal of the operational amplifier U1 is grounded, the positive and negative power supply terminals of the operational amplifier U1 are connected to the positive and negative power supply and filtered through capacitors C5 and C6, the output terminal of the operational amplifier U1 outputs the converted voltage signal, the output terminal is divided through resistor R6, potentiometer VR1 and thermistor PTC1 and then added to the base of the transistor Q1A, the output terminal is also connected to the collector of the transistor Q1D through capacitor C7, the base of the transistor Q1D is grounded, and the emitters of the transistor Q1D and the transistor Q1A are connected; The reference voltage source is connected to the non-inverting input terminal and the inverting input terminal of the operational amplifier U2 through resistors R1, R2 and R4, the positive and negative power supply terminals of the operational amplifier U2 are connected to the positive and negative power supply and filtered through capacitors C2 and C3, and the output terminal of the operational amplifier U2 is connected to the emitters of the transistors Q1D and Q1A through resistor R3, and the output terminal of the operational amplifier U2 is connected to the inverting input terminal of itself and the collector of the transistor Q1A through capacitor C1.

3. A cold cathode ion gauge drive pick-up circuit as claimed in claim 2, wherein, The size of the voltage signal is determined by the fixed current flowing through the resistor R6, the potentiometer VR1, the thermistor PTC1, the Boltzmann constant k, the absolute temperature t, the electronic charge q, the ion flow signal and the collector current of the transistor Q1A.

4. A cold cathode ion gauge drive pick-up circuit as claimed in claim 1, wherein, The current monitoring circuit comprises: operational amplifier U3A, operational amplifier U3B, diode D5, diode D6, resistor R14, resistor R15, resistor R17, pull-down resistor R16, capacitor C9, capacitor C10, capacitor C11 and capacitor C12. The voltage signal output by the ion flow logarithmic acquisition circuit is connected to the inverting input terminal of the operational amplifier U3A through resistor R15, the inverting input terminal of the operational amplifier U3A is connected to the output terminal of itself through the filtering circuit composed of resistor R14 and capacitor C10, diode D5 and capacitor C9, the non-inverting input terminal of the operational amplifier U3A is grounded through resistor R17, the output terminal of the operational amplifier U3A is connected to the non-inverting output terminal of the operational amplifier U3B through diode D6, the non-inverting input terminal of the operational amplifier U3B is also grounded through resistor R16, the inverting output terminal of the operational amplifier U3B is connected to the output terminal of itself, the positive and negative power supply terminals of the operational amplifier U3B are connected to the positive and negative power supply and grounded through capacitors C11 and C12, and the output terminal of the operational amplifier U3B outputs the control signal.

5. A cold cathode ion gauge drive pick-up circuit as claimed in claim 4, wherein, The cathode of the diode D5 is connected to the inverting input terminal of the operational amplifier U3A, and the anode is connected to the output terminal of the operational amplifier U3A, and the cathode of the diode D6 is connected to the output terminal of the operational amplifier U3A, and the anode is connected to the non-inverting output terminal of the operational amplifier U3B.

6. A cold cathode ion gauge drive pick-up circuit as claimed in claim 1, wherein, The voltage-controlled high-voltage drive circuit comprises: a voltage regulating circuit, a Royer push-pull self-oscillation circuit and a voltage doubling rectifier circuit. The voltage regulating circuit outputs a direct current voltage according to the control signal output by the current monitoring circuit. The Royer push-pull self-excitation circuit inverts the direct current voltage and outputs alternating current high voltage through a transformer; The voltage doubling rectifier circuit adjusts the alternating current high voltage to direct current high voltage output.

7. A cold cathode ion gauge drive pick-up circuit as claimed in claim 6, wherein, The voltage regulating circuit comprises an adjustable voltage stabilizer U4, a potentiometer VR2, a resistor R22, a resistor R18, and a capacitor C13. The control signal output by the current monitoring circuit is connected to the adjustment end of the adjustable voltage stabilizer U4 through the potentiometer VR2, the resistor R22, and the resistor R18. The input end of the adjustable voltage stabilizer U4 is connected to the power supply and filtered by the capacitor C13. The output end of the adjustable voltage stabilizer U4 outputs direct current voltage. The output end is connected to the connection point of the resistor R22 and the resistor R18. The Royer push-pull self-excitation circuit comprises a resistor R23, an electrolytic capacitor C15, an electrolytic capacitor C19, a resistor R19, a resistor R24, a capacitor C20, a capacitor C14, a capacitor C17, a transistor Q1, a transistor Q2, and a transformer T1. The transformer comprises a first transformer primary side, a second transformer primary side, and a transformer secondary side. The direct current voltage output by the adjustable voltage stabilizer U4 is connected to the center tap of the first transformer primary side through the electrolytic capacitor C15. The direct current voltage output by the adjustable voltage stabilizer U4 is connected to the center tap of the second transformer primary side through the resistor R23, the capacitor C20, and the electrolytic capacitor C19. The non-identical end of the first transformer primary side is connected to the identical end of the second transformer primary side through the transistor Q1 and the resistor R19. The identical end of the first transformer primary side is connected to the non-identical end of the second transformer primary side through the transistor Q2 and the resistor R24. The collector of the transistor Q1 is connected to the base of the transistor Q1 through the capacitor C14. The collector of the transistor Q2 is connected to the base of the transistor Q2 through the capacitor C17. The emitters of the transistor Q1 and the transistor Q2 are connected to the ground. The transformer secondary side outputs alternating current high voltage. The voltage doubling rectifier circuit comprises a high-voltage capacitor C16, a high-voltage capacitor C18, a high-voltage diode D1, and a high-voltage diode D2. The alternating current high voltage output by the transformer secondary side is connected in series with the high-voltage capacitor C16 and connected in parallel with the high-voltage diode D1. The high-voltage diode D2 is connected in series with the high-voltage diode D1 and connected in parallel with the high-voltage capacitor C18. The high-voltage capacitor C18 is connected in parallel with a load resistor R25. One end of the load resistor R25 is connected to the ground through a current-limiting resistor R20 and a current-limiting resistor R21, and outputs direct current high voltage.

8. A cold cathode ionization gauge drive pick-up circuit as claimed in claim 1, characterized in that The non-linear compensation branch comprises a reference voltage source, a resistor R25, a resistor R28, a diode D8, a resistor R26, a resistor R29, a resistor R30, and a potentiometer VR3. The reference voltage source is connected to the inverting input end of an operational amplifier U2A through the resistor R25, the resistor R28, the resistor R29, and the resistor R30. The connection point of the resistor R28 and the resistor R29 is connected to the control signal output by the current monitoring circuit. The connection point of the resistor R25 and the resistor R28 is connected to the inverting input end of the operational amplifier U2A through the diode D8, the resistor R26, and the potentiometer VR3.

9. A cold cathode ion gauge drive pick-up circuit as claimed in claim 8, characterised in that, When the ion current signal is less than the threshold value, the control signal voltage V HV_Adj is maintained at 0V, at this time only the signal output by operational amplifier U2B enters operational amplifier U2A, and the voltage at the output of operational amplifier U2A is: V U2BOut is the output voltage of operational amplifier U2B, which is related to the size of the ion current; When the circuit enters constant current mode through the negative feedback loop composed of the current monitoring circuit and the voltage-controlled high-voltage drive circuit, the voltage signal output by the ion current logarithmic acquisition circuit will be maintained at 0V, V U2BOut The output fixed value is involved in the addition operation, and the control signal voltage V HV_Adj From 0V to negative voltage direction, only resistance R29 and resistance R30 participate in feedback operation before diode D8 is turned on, at which time the voltage output by operational amplifier U2A is: The control signal voltage V HV_Adj After diode D8 is turned on, resistance R26 and potentiometer VR3 also participate in feedback operation, at which time the voltage output by operational amplifier U2A is: Where V D7 is the on-voltage drop of diode D7, V D7N is the voltage applied to the cathode of diode D7.

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