A pulse signal generating circuit for time-of-flight mass spectrometer

Abstract

The present invention provides a time-of-flight mass spectrometer pulse signal generating circuit, comprising: a square wave pulse generating module, an exponential pulse generating module, a non-isolated high voltage power supply, an isolated high voltage power supply, a first isolated driving module, a second isolated driving module and a third isolated driving module; using the circuit of the present application, the direct current generated by the isolated high voltage power supply and the non-isolated high voltage power supply can be converted into a pulse electric signal capable of driving ions in an extraction zone of a mass spectrometer, and an exponential pulse signal is superimposed on the square wave pulse signal while generating a square wave pulse signal, and after the superimposed pulse voltage is applied to the extraction electrode plate, the waiting zone can be transferred to the acceleration zone, thereby making ions of the same mass arrive at the analyzer as simultaneously as possible, so as to improve the resolution of the mass spectrometer.

Description

Technical Field

[0001] The present invention relates to the technical field of mutual conversion between direct current and alternating current, and more specifically, to a pulse signal generating circuit for a time-of-flight mass spectrometer. Background Art

[0002] A mass spectrometer, also known as a mass spectrometer, is a type of instrument that uses the principle that charged particles can be deflected in an electromagnetic field to separate and detect the composition of substances according to the mass differences of atoms, molecules or molecular fragments of substances. It is widely used in the field of life sciences. In particular, time-of-flight mass spectrometers, with their unique high sensitivity and high-quality detection range, have promoted the widespread application and development of mass spectrometry technology in the field of life sciences.

[0003] The Chinese invention patent (application number: CN201810149729.3) proposes a method for improving the resolution of mass spectrometry, by obtaining the waiting time after ionization when the object to be detected is ionized into ions in the extraction zone of the online aerosol mass spectrometer; according to the extraction electrode voltage adjustment function and the waiting time after ionization, a target voltage value that changes continuously within the preset ion flight time range is obtained, and the target voltage value is sent to the pulse control circuit of the online aerosol mass spectrometer; the target voltage value is used to instruct the pulse control circuit to adjust the pulse voltage applied to the extraction electrode to improve the resolution of the mass spectrometer; wherein the extraction electrode voltage adjustment function is used to record the corresponding relationship between the voltage applied to the extraction electrode and the flight time. The above method for improving the resolution of mass spectrometry applies a variable voltage to the extraction electrode, so that the time for ions of the same mass to enter the acceleration zone and reach the detector is basically the same, thereby improving the resolution of the mass spectrometer, and the detection resolution is significantly improved. However, the application only discloses that the lead-out electrode and the accelerating electrode are isolated from each other, and describes the parameters of the pulse voltage applied to the lead-out electrode, specifically a pulse signal in which a square wave pulse signal and an exponential pulse signal are superimposed on each other. However, the application does not disclose what specific circuit is used to generate the above-mentioned superimposed pulse signal. Summary of the invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a time-of-flight mass spectrometer pulse signal generating circuit, which converts the DC signal output by the original DC power supply into a pulse electrical signal that can drive ion movement as needed, so as to overcome the defects existing in the above-mentioned background technology.

[0005] The above technical purpose of the present invention is achieved through the following technical solutions: a time-of-flight mass spectrometer pulse signal generating circuit, characterized in that it includes: a square wave pulse generating module, an exponential pulse generating module, a non-isolated high-voltage power supply for providing a DC voltage to the square wave pulse generating module, an isolated high-voltage power supply for providing a DC voltage to the exponential pulse generating module, a first isolation driving module for controlling the switch of the exponential pulse generating module to be turned on or off according to an input first control signal, a second isolation driving module for controlling the upper switch of the square wave pulse generating module to be turned on or off according to an input second control signal, and a A third isolation driving module controls the on or off of the lower switch of the square wave pulse generating module; the output end of the non-isolated high-voltage power supply is electrically connected to the power supply end of the square wave pulse generating module; the output end of the second isolation driving module and the output end of the third isolation driving module are both electrically connected to the input end of the square wave pulse generating module; the output end of the isolated high-voltage power supply is electrically connected to the power supply end of the exponential pulse generating module and the power supply end of the square wave pulse generating module respectively; the output end of the first isolation driving module is electrically connected to the input end of the exponential pulse generating module; so the output end of the exponential pulse generating module is electrically connected to the output end of the square wave pulse generating module.

[0006] In one embodiment, the square wave pulse generating module includes: an upper switch unit for controlling the application of the power supply voltage to realize the charging of the load and a lower switch unit for controlling the grounding of the load to realize the rapid discharge of the load; the signal input end of the upper switch unit is electrically connected to the output end of the second isolation driving module; the power supply end of the upper switch unit is electrically connected to the non-isolated high-voltage power supply and the isolated high-voltage power supply respectively; the output end of the upper switch unit is electrically connected to the exponential pulse generating module; the signal input end of the lower switch unit is electrically connected to the output end of the third isolation driving module; the power supply end of the lower switch unit is electrically connected to the exponential pulse generating module; and the output end of the lower switch unit is grounded.

[0007] In one embodiment, the upper switch unit specifically includes: a first resistor, a second resistor, a first capacitor and a first MOS tube; the gate of the first MOS tube is electrically connected to the output end of the second isolation driving module after passing through the first resistor; the gate of the first MOS tube is electrically connected to the second isolation driving module after passing through the second resistor; the source of the first MOS tube is electrically connected to the second isolation driving module; the source of the first MOS tube is also electrically connected to the exponential pulse generating module; the drain of the first MOS tube is grounded after passing through the first capacitor; the drain of the first MOS tube is also electrically connected to the output end of the non-isolated high-voltage power supply.

[0008] In one embodiment, the lower switch unit specifically includes: a third resistor, a fourth resistor, a fifth resistor and a second MOS tube; the gate of the second MOS tube is electrically connected to the output end of the third isolation driving module after passing through the third resistor; the gate of the second MOS tube is also grounded after passing through the fourth resistor; the source of the second MOS tube is grounded; the drain of the second MOS tube is electrically connected to the exponential pulse generation module after passing through the fifth resistor.

[0009] In one embodiment, the exponential pulse generation module specifically includes: a third MOS tube, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a second capacitor, a third capacitor and a diode; the drain of the third MOS tube is electrically connected to the output end of the isolated high-voltage power supply; the gate of the third MOS tube is electrically connected to the first isolation driving module after passing through the sixth resistor; the gate of the third MOS tube is also electrically connected to the first isolation driving module after passing through the seventh resistor; the gate of the third MOS tube is electrically connected to the source of the third MOS tube after passing through the seventh resistor; the source of the third MOS tube is electrically connected to the cathode of the diode after passing through the eighth resistor and the second capacitor in sequence; the anode of the diode is grounded; the cathode of the diode is grounded after passing through the third capacitor; the cathode of the diode is grounded after passing through the ninth resistor; the cathode of the diode is also electrically connected to the source of the first MOS tube; the cathode of the diode is electrically connected to the drain of the second MOS tube after passing through the second capacitor and the fifth resistor in sequence.

[0010] In one embodiment, the first isolation driving module includes: a first isolation driving chip, a fourth capacitor and a tenth resistor; the first pin of the first isolation driving chip is electrically connected to the first control signal source; the third pin of the first isolation driving chip is connected to the 5V power supply terminal; the third pin of the first isolation driving chip is also grounded after passing through the fourth capacitor; the fourth and fifth pins of the first isolation driving chip are grounded; the sixth pin of the first isolation driving chip is electrically connected to the eighth pin of the first isolation driving chip after passing through the tenth resistor; the fourteenth and fifteenth pins of the first isolation driving chip are both electrically connected to the exponential pulse generating module; the sixteenth pin of the first isolation driving chip is electrically connected to the 12V voltage terminal.

[0011] In one embodiment, the second isolation driving module includes: a first isolation driving chip, a fourth capacitor and a tenth resistor; the second pin of the first isolation driving chip is electrically connected to the first control signal source; the third pin of the first isolation driving chip is connected to the 5V power supply end; the third pin of the first isolation driving chip is also grounded after passing through the fourth capacitor; the fourth and fifth pins of the first isolation driving chip are grounded; the sixth pin of the first isolation driving chip is electrically connected to the eighth pin of the first isolation driving chip after passing through the tenth resistor; the ninth and tenth pins of the first isolation driving chip are both electrically connected to the square wave pulse generating module; the eleventh pin of the first isolation driving chip is electrically connected to the 12V voltage end.

[0012] In one embodiment, the third isolation driving module includes: a second isolation driving chip, a fifth capacitor and an eleventh resistor; the second pin of the second isolation driving chip is electrically connected to the second control signal source; the third pin of the second isolation driving chip is connected to the 5V power supply terminal; the third pin of the second isolation driving chip is also grounded after passing through the fifth capacitor; the fourth and fifth pins of the second isolation driving chip are grounded; the sixth pin of the second isolation driving chip is electrically connected to the eighth pin of the second isolation driving chip after passing through the eleventh resistor; the ninth pin of the first isolation driving chip is grounded; the eleventh pin of the second isolation driving chip is electrically connected to the square wave pulse generating module.

[0013] In one embodiment, the first control signal is a TTL signal; and the second control signal is a TTL signal.

[0014] In one embodiment, a phase of the first control signal differs from a phase of the second control signal by 180°.

[0015] In summary, the present invention has the following beneficial effects: a time-of-flight mass spectrometer pulse signal generating circuit, comprising: a square wave pulse generating module, an exponential pulse generating module, a non-isolated high-voltage power supply for providing a DC voltage to the square wave pulse generating module, an isolated high-voltage power supply for providing a DC voltage to the exponential pulse generating module, a first isolation driving module for controlling the switch of the exponential pulse generating module to be turned on or off according to an input first control signal, a second isolation driving module for controlling the upper switch of the square wave pulse generating module to be turned on or off according to an input first control signal, and a third isolation driving module for controlling the lower switch of the square wave pulse generating module to be turned on or off according to an input second control signal; using the circuit of the present application, while generating a square wave pulse signal, an exponential pulse signal can be superimposed on the square wave pulse signal, so as to apply the superimposed pulse voltage on the lead-out plate, so as to transfer the waiting area to the acceleration area, thereby making ions of the same mass arrive at the analyzer as simultaneously as possible, so as to improve the resolution of the mass spectrometer. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the structure of the acceleration zone and the lead-out zone in the prior art;

[0017] Figure 2 It is a function schematic diagram of the incremental lead-out pole piece voltage regulation function in the prior art;

[0018] Figure 3 The principle block diagram of the invented time-of-flight mass spectrometer pulse signal generating circuit;

[0019] Figure 4 The invention is a circuit schematic diagram of a pulse signal generating circuit for a time-of-flight mass spectrometer.

[0020] In the figure: 1. First isolation driving module; 2. Second isolation driving module; 3. Third isolation driving module; 4. Square wave pulse generating module; 5. Exponential pulse generating module; 6. Non-isolated high voltage power supply; 7. Isolated high voltage power supply. DETAILED DESCRIPTION

[0021] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings. Several embodiments of the present invention are shown in the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein.

[0022] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances. The terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0023] In the present invention, unless otherwise clearly specified and limited, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, the first feature being "above", "above" and "above" the second feature includes the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature includes the first feature being directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature. The terms "vertical", "horizontal", "left", "right", "above", "below" and similar expressions are for illustrative purposes only, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0024] The present invention is described in detail below with reference to the accompanying drawings and embodiments. To facilitate understanding of the embodiments, the relevant technology is first described. In mass spectrometry analysis, the mass spectrometer needs to ionize particles into ions, and then use an electric field to drive the ions to fly to the mass spectrometer sensor, calculate the charge-to-mass ratio of the ions based on the flight time of the ions, and then analyze the number and type of compounds in the sample based on the composition of the ions. Figure 1 As shown, a commonly used bipolar time-of-flight mass spectrometer includes two acceleration zones (used to accelerate positive ions and negative ions respectively), and a common extraction zone between the two acceleration zones, that is, the middle position of the two acceleration zones is the extraction zone, and the acceleration zone is composed of a plurality of voltage divider electrodes (all electrodes except the acceleration electrode) and an acceleration electrode, and the extraction zone is composed of two extraction electrodes, wherein the voltage divider electrode is arranged next to the extraction electrode. The particulate matter (the object to be detected) is ionized by laser at the center of the extraction zone, and the generated positive and negative ions are then accelerated in the acceleration zone in opposite directions. Under the action of the electric field, ions of different masses will be accelerated to different speeds. After the acceleration is completed, they are detected by two mass analyzers respectively. Therefore, the charge-to-mass ratio of the ions can be calculated according to the flight time of the ions. When the object to be detected is ionized into ions, an explosion phenomenon often occurs, so that the positive and negative ions formed have a larger initial speed, and the speeds of ions of the same mass are often different, thereby affecting the resolution of the online aerosol mass spectrometer.

[0025] The previous Chinese patent application proposed that by changing the voltage parameters on the extraction electrode, the voltage parameters of the extraction zone are changed from the traditional DC voltage to the pulse voltage, which can effectively reduce the influence of the initial velocity of the object to be detected on the detection accuracy. Specifically, the DC voltage on the extraction electrode is changed to a pulse voltage, and the low-level time length of the pulse voltage is the waiting time after the particle is ionized. The specific meaning of the waiting time is to wait for the kinetic energy generated by the ions after the explosion to be consumed, so that the movement of ions of various masses tends to be stable, and then adjust the pulse voltage to a high level, so that the ions in the extraction zone can be pulled into the acceleration zone by the electric field of the extraction zone when the motion state is close. Thereby, the time for ions of the same mass to enter the acceleration zone and reach the detector is basically the same, which effectively improves the resolution of the mass spectrometer.

[0026] At the same time, if Figure 2 As shown, the application also discloses the use of the following incremental lead-out electrode voltage adjustment function to calculate the target voltage value that changes continuously within a preset ion flight time range:

[0027]

[0028]

[0029] in, represents the target voltage value, is the pulse amplitude of the square wave function, represents the exponential function, A variable representing the ion flight time, Indicates the waiting time after laser ionization, represents the exponential pulse rise time, Indicates the time after the pulse stabilizes, The pulse amplitude represents the exponential function. However, the patent does not disclose what means or circuits can be used to convert the original DC signal into a pulsed electrical signal that drives the movement of ions.

[0030] Embodiment 1

[0031] In order to solve the above problems, the present invention provides a time-of-flight mass spectrometer pulse signal generating circuit, such as Figure 2 , Figure 3As shown, it includes: a square wave pulse generating module 4, an exponential pulse generating module 5, a non-isolated high-voltage power supply 6 for providing a DC voltage to the square wave pulse generating module 4, an isolated high-voltage power supply 7 for providing a DC voltage to the exponential pulse generating module 5, a first isolation driving module 1 for controlling the switch of the exponential pulse generating module 5 to be turned on or off according to an input first control signal, a second isolation driving module 2 for controlling the upper switch of the square wave pulse generating module 4 to be turned on or off according to an input first control signal, and a third isolation driving module 3 for controlling the lower switch of the square wave pulse generating module 4 to be turned on or off according to an input second control signal. Three isolated driving modules 3; the output end of the non-isolated high-voltage power supply 6 is electrically connected to the power supply end of the square wave pulse generating module 4; the output end of the second isolated driving module 2 and the output end of the third isolated driving module 3 are both electrically connected to the input end of the square wave pulse generating module 4; the output end of the isolated high-voltage power supply 7 is electrically connected to the power supply end of the exponential pulse generating module 5 and the power supply end of the square wave pulse generating module 4 respectively; the output end of the first isolated driving module 1 is electrically connected to the input end of the exponential pulse generating module 5; so the output end of the exponential pulse generating module 5 is electrically connected to the output end of the square wave pulse generating module 4.

[0032] In the present application, the non-isolated controllable high-voltage power supply is a DC output voltage, which provides the required voltage for the square wave pulse generating module 4, and the isolated controllable high-voltage power supply is a DC output, which provides the required voltage for the exponential pulse generating module 5. In the present application, the final superposition voltage used to drive the ions in the waiting area is the result of the superposition of the pulse voltages generated by the square wave pulse generating module 4 and the exponential pulse generating module 5. Among them, the amplitude adjustment of the exponential pulse is achieved by adjusting the voltage of the isolated controllable high-voltage power supply. The amplitude adjustment of the square wave pulse is achieved by adjusting the voltage of the non-isolated controllable high-voltage power supply.

[0033] In summary, the present application proposes a pulse circuit that can simultaneously generate square wave pulses and exponential pulses. By superimposing the pulse signals generated by the two circuits, a superimposed voltage required by the extraction electrode can be obtained, so that when the extraction electrode drives the ions to move, the pulse voltage above can first wait for a period of time to stabilize the ion movement area in the extraction zone, and then use the superimposed voltage to drive the ion movement, so that ions of the same mass can arrive at the analyzer at the same time as much as possible, thereby effectively improving the resolution of the mass spectrometer.

[0034] In one embodiment, the square wave pulse generating module 4 includes: an upper switch unit for controlling the application of the power supply voltage to realize the charging of the load and a lower switch unit for controlling the grounding of the load to realize the rapid discharge of the load; the signal input end of the upper switch unit is electrically connected to the output end of the second isolation driving module 2; the power supply end of the upper switch unit is electrically connected to the non-isolated high-voltage power supply 6 and the isolated high-voltage power supply 7 respectively; the output end of the upper switch unit is electrically connected to the exponential pulse generating module 5; the signal input end of the lower switch unit is electrically connected to the output end of the third isolation driving module 3; the power supply end of the lower switch unit is electrically connected to the exponential pulse generating module 5; the output end of the lower switch unit is grounded.

[0035] Specifically, the square wave pulse generating module 4 includes an upper switch unit and a lower switch unit, wherein the upper switch unit is connected between the non-isolated high voltage power supply 6 and the load, and when the upper switch is turned on, it applies the power supply voltage to the load, thereby generating a positive voltage pulse; the lower switch unit is connected between the load and the ground, and the upper switch is responsible for controlling the application of the power supply voltage, thereby realizing high voltage side control of the load; and is used to realize fast charging or acceleration of the load. When the lower switch is turned on, a grounding path is provided for the load, so that the current on the load can flow back to the negative pole of the power supply, and the lower switch is responsible for controlling the grounding of the load, thereby realizing low voltage side control of the load, and is used to realize fast discharge or deceleration of the load.

[0036] In one embodiment, the upper switch unit specifically includes: a first resistor R1, a second resistor R2, a first capacitor C1 and a first MOS tube Q1; the gate of the first MOS tube Q1 is electrically connected to the output end of the second isolation driving module 2 after passing through the first resistor R1; the gate of the first MOS tube Q1 is electrically connected to the second isolation driving module 2 after passing through the second resistor R2; the source of the first MOS tube Q1 is electrically connected to the second isolation driving module 2; the source of the first MOS tube Q1 is also electrically connected to the exponential pulse generating module 5; the drain of the first MOS tube Q1 is grounded after passing through the first capacitor C1; the drain of the first MOS tube Q1 is also electrically connected to the output end of the non-isolated high-voltage power supply 6.

[0037] In one embodiment, the lower switch unit specifically includes: a third resistor R3, a fourth resistor R4, a fifth resistor R5 and a second MOS tube Q2; the gate of the second MOS tube Q2 is electrically connected to the output end of the third isolation driving module 3 after passing through the third resistor R3; the gate of the second MOS tube Q2 is also grounded after passing through the fourth resistor R4; the source of the second MOS tube Q2 is grounded; the drain of the second MOS tube Q2 is electrically connected to the exponential pulse generating module 5 after passing through the fifth resistor R5.

[0038] In the present application, the non-isolated high-voltage power supply 6 is used to increase the voltage for the square wave pulse generating module 4. When the first control signal received by the second isolation driving module 2 is at a high level, the drain and source pins of the first MOS tube Q1 are turned on. The second control signal received by the third isolation driving module 3 at this time is at a low level, and the drain and source pins of the second MOS tube Q2 are turned off. At this time, the positive output voltage of the non-isolated power supply charges the third capacitor C3. Since the current in the MOS tube is very large and the value of the third capacitor C3 is very small, the voltage across the third capacitor C3 reaches the non-isolated output voltage in a very short time (20-100nS). The output of the pulse is a high level. When the level of the first control signal and the second control signal is flipped, similarly, the drain and source pins of the first MOS tube Q1 are turned off, and the drain and source pins of the second MOS tube Q2 are turned on. The charge on the third capacitor C3 is released through the second capacitor C2, the fifth resistor R5, and the second MOS tube Q2 and then grounded, and is low level after the release is completed.

[0039] In one embodiment, the exponential pulse generating module 5 specifically includes: a third MOS tube Q3, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a second capacitor C2, a third capacitor C3 and a diode D1; the drain of the third MOS tube Q3 is electrically connected to the output end of the isolated high voltage power supply 7; the gate of the third MOS tube Q3 is electrically connected to the first isolation driving module 1 after passing through the sixth resistor R6; the gate of the third MOS tube Q3 is also electrically connected to the first isolation driving module 1 after passing through the seventh resistor R7; the gate of the third MOS tube Q3 is electrically connected to the first isolation driving module 1 after passing through the seventh resistor R7; The seventh resistor R7 is electrically connected to the source of the third MOS tube Q3; the source of the third MOS tube Q3 is electrically connected to the cathode of the diode D1 after passing through the eighth resistor R8 and the second capacitor C2 in sequence; the anode of the diode D1 is grounded; the cathode of the diode D1 is grounded after passing through the third capacitor C; the cathode of the diode D1 is grounded after passing through the ninth resistor R9; the cathode of the diode D1 is also electrically connected to the source of the first MOS tube Q1; the cathode of the diode D1 is electrically connected to the drain of the second MOS tube Q2 after passing through the second capacitor C2 and the fifth resistor R5 in sequence.

[0040] In the present application, the state of the third MOS transistor Q3 in the exponential pulse generating module 5 is consistent with that of the first MOS transistor Q1 in the square wave pulse generating module 4, so when the first MOS transistor Q1 is turned on, the third MOS transistor Q3 is also turned on; so when the pulse level reaches a high level, the isolated high voltage charges the second capacitor C through the third MOS transistor Q3, the eighth resistor R, and the first MOS transistor Q1 to form an exponential voltage, and the relationship is:

[0041]

[0042] The relationship between the exponential voltage and the square wave pulse voltage superposition is:

[0043]

[0044] in, The isolated high voltage received by the exponential pulse generation module; It is the non-isolated high voltage received by the square wave pulse generation module. It is the exponential voltage output by the exponential pulse generation module. is the output superimposed pulse exponential voltage.

[0045] Since the second capacitor C2 is superimposed on the third capacitor C3, the relationship between them is in series, and the voltage U1 of the isolated high-voltage power supply 7 is superimposed on the voltage U2 of the non-isolated high-voltage power supply 6, the relationship between them is in series. Therefore, the exponential voltage is synthesized on the pulse voltage. The second capacitor C2 plays a key role in the formation of the exponential voltage and the superposition on the pulse voltage. The role of the diode is to provide a release loop for the charge accumulated in the charging process of the second capacitor C2. The third capacitor C reduces the process voltage generated by the high-speed current on the rising edge of the pulse voltage, providing a higher quality for the exponential pulse.

[0046] In one embodiment, the first isolation driving module 1 includes: a first isolation driving chip U1, a fourth capacitor C4 and a tenth resistor R10; the first pin of the first isolation driving chip U1 is electrically connected to the first control signal source; the third pin of the first isolation driving chip U1 is connected to the 5V power supply terminal; the third pin of the first isolation driving chip U1 is also grounded after passing through the fourth capacitor C4; the fourth and fifth pins of the first isolation driving chip U1 are grounded; the sixth pin of the first isolation driving chip U1 is electrically connected to the eighth pin of the first isolation driving chip U1 after passing through the tenth resistor R10; the fourteenth and fifteenth pins of the first isolation driving chip U1 are both electrically connected to the exponential pulse generating module 5; the sixteenth pin of the first isolation driving chip U1 is electrically connected to the 12V voltage terminal.

[0047] The first isolation driver chip U1 uses an isolation driver IC model NSI6602; the primary and secondary sides have 2500RMS isolation. In the present application, the first isolation driver chip U1 can control the level of the output signal of the tenth pin and the fifteenth pin respectively according to the signal input to the first pin and the signal input to the second pin. In the present application, by setting the isolation driver module, the input and output of the driver module can be isolated from each other to avoid crosstalk.

[0048] In one embodiment, the second isolation driving module 2 includes: a first isolation driving chip U1, a fourth capacitor C4 and a tenth resistor R10; the second pin of the first isolation driving chip U1 is electrically connected to the first control signal source; the third pin of the first isolation driving chip U1 is connected to the 5V power supply end; the third pin of the first isolation driving chip U1 is also grounded after passing through the fourth capacitor C4; the fourth and fifth pins of the first isolation driving chip U1 are grounded; the sixth pin of the first isolation driving chip U1 is electrically connected to the eighth pin of the first isolation driving chip U1 after passing through the tenth resistor R10; the ninth and tenth pins of the first isolation driving chip U1 are both electrically connected to the square wave pulse generating module 4; the eleventh pin of the first isolation driving chip U1 is electrically connected to the 12V voltage end.

[0049] In the present application, since it is necessary to control the first MOS tube Q1 and the third MOS tube Q3 to be turned on and off synchronously, the first pin and the second pin of the first isolation driver chip U1 can be connected to the same control signal so that the control can simultaneously drive the first MOS tube Q1 and the third MOS tube Q3 to be turned on or off synchronously.

[0050] In one embodiment, the third isolation driving module 3 includes: a second isolation driving chip U2, a fifth capacitor C5 and an eleventh resistor R11; the second pin of the second isolation driving chip U2 is electrically connected to the second control signal source; the third pin of the second isolation driving chip U2 is connected to the 5V power supply end; the third pin of the second isolation driving chip U2 is also grounded after passing through the fifth capacitor C5; the fourth and fifth pins of the second isolation driving chip U2 are grounded; the sixth pin of the second isolation driving chip U2 is electrically connected to the eighth pin of the second isolation driving chip U2 after passing through the eleventh resistor R; the ninth pin of the second isolation driving chip U2 is grounded; the eleventh pin of the second isolation driving chip U2 is electrically connected to the square wave pulse generating module.

[0051] In the present application, the second isolation driver chip U2 also uses an isolation driver IC of model NSI6602; the primary and secondary sides have 2500RMS isolation. The second isolation driver chip U2 can also provide two drive signals at the same time. In the present application, only the second drive signal is used. When the second pin of the second isolation driver chip U2 receives a high level, the eleventh pin of the isolation driver chip, that is, the VDDB output terminal, can output a high level. When the high level is output, the second MOS tube Q2 is turned on, so the charge in the third capacitor C3 is released after passing through the second capacitor C2, the fifth resistor R5 and the second MOS tube Q2. After the release, the two ends of the second capacitor C2 are low levels, so the voltage on the lead-out electrode connected to the output end can be weakened, which also weakens the electric field force of the electric field released by the lead-out electrode, reducing the driving force of the electric field.

[0052] In one embodiment, the first control signal is a TTL (transistor transistor logic) signal; the second control signal is a TTL signal.

[0053] In one embodiment, the phase of the first control signal is 180° different from the phase of the second control signal. In the present application, the first control signal is used to control the square wave pulse and the exponential pulse to generate a rising edge, thereby applying a voltage to the lead-out electrode to form an electric field for driving ions; the second control signal is used to control the opening of the lower switch unit, thereby allowing the electric energy on the load to pass through the lower switch unit back to the negative electrode or be introduced into the ground terminal. Therefore, the first control signal and the second control signal need to be relatively opened respectively to prevent the electric energy from directly entering the negative electrode of the power supply.

[0054] In one embodiment, the first control signal and the second control signal are complementary 3.3V pulse signals, and there is a dead time between the corresponding rising and falling edges of the two signals. In the present application, the dead time is set to about 100ns. Setting the dead time helps to reduce the stress of the switching device and extend its life. The switching device will experience transient changes in voltage and current during the process of turning on and off. The appropriate dead time can reduce the overlap of these transients, thereby reducing losses and heat. By introducing the dead time, the reliability and stability of the entire circuit system can be improved, and circuit failures caused by instantaneous high currents can be avoided.

[0055] In summary, the present application provides a pulse signal generating circuit of an exponential pulse superimposed with a square wave pulse. By using the circuit of the present application, an exponential pulse signal can be superimposed on the square wave pulse signal while generating a square wave pulse signal, so as to apply the superimposed pulse voltage on the lead-out plate, so as to transfer the waiting area to the acceleration area, and then make ions of the same mass arrive at the analyzer as simultaneously as possible, so as to improve the resolution of the mass spectrometer.

[0056] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0057] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0058] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A time-of-flight mass spectrometer pulse signal generating circuit, characterized in that: include: A square wave pulse generating module, an exponential pulse generating module, a non-isolated high-voltage power supply for providing a DC voltage to the square wave pulse generating module, an isolated high-voltage power supply for providing a DC voltage to the exponential pulse generating module, a first isolation driving module for controlling the switch of the exponential pulse generating module to be turned on or off according to an input first control signal, a second isolation driving module for controlling the upper switch of the square wave pulse generating module to be turned on or off according to an input first control signal, and a third isolation driving module for controlling the lower switch of the square wave pulse generating module to be turned on or off according to an input second control signal; The output end of the non-isolated high-voltage power supply is electrically connected to the power supply end of the square wave pulse generating module; The output end of the second isolation driving module and the output end of the third isolation driving module are both electrically connected to the input end of the square wave pulse generating module; The output end of the isolated high-voltage power supply is electrically connected to the power supply end of the exponential pulse generating module and the power supply end of the square wave pulse generating module respectively; The output end of the first isolation driving module is electrically connected to the input end of the exponential pulse generating module; Therefore, the output end of the exponential pulse generating module is electrically connected to the output end of the square wave pulse generating module.

2. A time-of-flight mass spectrometer pulse signal generating circuit according to claim 1, characterized in that: The square wave pulse generating module comprises: an upper switch unit for controlling the application of the power supply voltage to realize the charging of the load and a lower switch unit for controlling the grounding of the load to realize the rapid discharge of the load; The signal input end of the upper switch unit is electrically connected to the output end of the second isolation driving module; the power supply end of the upper switch unit is electrically connected to the non-isolated high-voltage power supply and the isolated high-voltage power supply respectively; the output end of the upper switch unit is electrically connected to the exponential pulse generating module; The signal input end of the lower switch unit is electrically connected to the output end of the third isolation driving module; the power supply end of the lower switch unit is electrically connected to the exponential pulse generating module; and the output end of the lower switch unit is grounded.

3. A time-of-flight mass spectrometer pulse signal generating circuit according to claim 2, characterized in that: The upper switch unit specifically includes: a first resistor, a second resistor, a first capacitor and a first MOS tube; The gate of the first MOS tube is electrically connected to the output end of the second isolation driving module through a first resistor; The gate of the first MOS tube is electrically connected to the second isolation driving module through a second resistor; The source of the first MOS tube is electrically connected to the second isolation driving module; The source of the first MOS tube is also electrically connected to the exponential pulse generating module; The drain of the first MOS tube is grounded after passing through the first capacitor; the drain of the first MOS tube is also electrically connected to the output end of the non-isolated high-voltage power supply.

4. A time-of-flight mass spectrometer pulse signal generating circuit according to claim 3, characterized in that: The lower switch unit specifically includes: a third resistor, a fourth resistor, a fifth resistor and a second MOS tube; The gate of the second MOS tube is electrically connected to the output end of the third isolation driving module after passing through the third resistor; The gate of the second MOS tube is also grounded after passing through a fourth resistor; The source of the second MOS tube is grounded; The drain of the second MOS tube is electrically connected to the exponential pulse generating module after passing through a fifth resistor.

5. A time-of-flight mass spectrometer pulse signal generating circuit according to claim 4, characterized in that: The exponential pulse generation module specifically includes: a third MOS tube, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a second capacitor, a third capacitor and a diode; The drain of the third MOS tube is electrically connected to the output end of the isolated high-voltage power supply; The gate of the third MOS tube is electrically connected to the first isolation driving module through a sixth resistor; The gate of the third MOS tube is also electrically connected to the first isolation driving module after passing through the seventh resistor; The gate of the third MOS tube is electrically connected to the source of the third MOS tube through a seventh resistor; The source of the third MOS tube is electrically connected to the cathode of the diode after passing through the eighth resistor and the second capacitor in sequence; the anode of the diode is grounded; The cathode of the diode is grounded after passing through a third capacitor; The cathode of the diode is grounded after passing through a ninth resistor; The cathode of the diode is also electrically connected to the source of the first MOS tube; The cathode of the diode is electrically connected to the drain of the second MOS tube after passing through the second capacitor and the fifth resistor in sequence.

6. The pulse signal generating circuit of a time-of-flight mass spectrometer according to claim 1, characterized in that: The first isolation driving module includes: a first isolation driving chip, a fourth capacitor and a tenth resistor; The first pin of the first isolation driving chip is electrically connected to the first control signal source; The third pin of the first isolation driving chip is connected to the 5V power supply terminal; the third pin of the first isolation driving chip is also grounded after passing through the fourth capacitor; The fourth pin and the fifth pin of the first isolation driving chip are grounded; The sixth pin of the first isolation driving chip is electrically connected to the eighth pin of the first isolation driving chip after passing through the tenth resistor; The fourteenth and fifteenth pins of the first isolation driving chip are both electrically connected to the exponential pulse generating module; The sixteenth pin of the first isolation driving chip is electrically connected to the 12V voltage terminal.

7. The pulse signal generating circuit of a time-of-flight mass spectrometer according to claim 1, characterized in that: The second isolation driving module includes: a first isolation driving chip, a fourth capacitor and a tenth resistor; The second pin of the first isolation driving chip is electrically connected to the first control signal source; The third pin of the first isolation driver chip is connected to the 5V power supply terminal; the third pin of the first isolation driver chip is also grounded after passing through the fourth capacitor; The fourth pin and the fifth pin of the first isolation driving chip are grounded; The sixth pin of the first isolation driving chip is electrically connected to the eighth pin of the first isolation driving chip after passing through a tenth resistor; The ninth pin and the tenth pin of the first isolation driving chip are both electrically connected to the square wave pulse generating module; The eleventh pin of the first isolation driving chip is electrically connected to the 12V voltage terminal.

8. The pulse signal generating circuit of a time-of-flight mass spectrometer according to claim 1, characterized in that: The third isolation driving module includes: a second isolation driving chip, a fifth capacitor and an eleventh resistor; The second pin of the second isolation driving chip is electrically connected to the second control signal source; The third pin of the second isolation driving chip is connected to the 5V power supply terminal; the third pin of the second isolation driving chip is also grounded after passing through the fifth capacitor; The fourth pin and the fifth pin of the second isolation driving chip are grounded; The sixth pin of the second isolation driving chip is electrically connected to the eighth pin of the second isolation driving chip after passing through an eleventh resistor; The ninth pin of the second isolation driving chip is grounded; The eleventh pin of the second isolation driving chip is electrically connected to the square wave pulse generating module.

9. The pulse signal generating circuit of a time-of-flight mass spectrometer according to claim 1, characterized in that: The first control signal is a TTL signal; the second control signal is a TTL signal.

10. A time-of-flight mass spectrometer pulse signal generating circuit according to claim 9, characterized in that: The phase of the first control signal differs from that of the second control signal by 180°.

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