High-voltage and high-speed ion gate pulse control circuit based on optoelectronic isolation

Abstract

The invention discloses a high-voltage high-speed ion gate pulse control circuit based on optoelectronic isolation. The high-voltage high-speed ion gate pulse control circuit comprises an optical fiber signal input circuit, a driving circuit, an optocoupler circuit, a power supply circuit and a high-voltage direct-current power supply module. According to the control circuit, complete electrical isolation of a system is achieved through the optical fiber and the high-voltage isolation optocoupler, rapid opening and closing of the ion gate are achieved, the edge of an output pulse is extremely steep, the detection sensitivity of a rear-end system can be improved to a certain degree, the control effect of the ion gate is improved, and the application field of an ion mobility spectrometry instrument is expanded.

Description

Technical Field

[0001] The invention relates to the technical field of ion mobility spectrometers, and in particular to a high-voltage and high-speed ion gate pulse control circuit based on photoelectric isolation. Background Art

[0002] As one of the core components of ion mobility spectrometry, the ion gate is used to control the ions to enter the drift region in a pulsed manner. Since the ions have different collision cross-sectional areas, the time they arrive at the detector is different, so spectra with different flight times can be obtained, that is, ion mobility spectra. There are usually two types of ion gates: Bradbury-Nielson type (abbreviated as BN type) ion gate and Tyndall-Powell type (abbreviated as TP type) ion gate. The BN type ion gate is composed of two sets of parallel electrodes that are insulated from each other and arranged alternately in the same plane. When there is a certain potential difference between the two sets of electrodes, an electric field perpendicular to the drift tube will be generated, blocking the flight path of the ion flow, forming a closed state; when the potentials of the two sets of electrodes are the same, the vertical electric field disappears, and the ion flow can pass through the gap between the electrodes and enter the drift tube, forming an open state. The TP type ion gate usually uses two parallel arranged grids (G1 close to the reaction area and G2 close to the drift area), and applies a positive or reverse electric field between grids G1 and G2, thereby promoting or blocking the flight of ions in the positive direction or in the reverse direction, forming an open or closed state.

[0003] In the gate control of ion mobility spectrometry, patent CN218215202U proposes to use a high-voltage power supply to power the drift tube voltage divider circuit and the gate voltage divider circuit at the same time, and the gate voltage divider circuit provides the pulse voltage required by the TP type ion gate; patent CN112820621B proposes to use two half-bridge drivers to form a full-bridge driver, and to achieve the output of pulse voltage by controlling the rotation conduction of the MOS tube. The above patents all control the change of potential through MOS tubes. The whole system uses more components and the operation is more complicated. At present, there are fewer optocouplers used for driving. Patent CN116190199A proposes an overlapping ion gate, but it requires two control branches, each branch requires two optocouplers, and a total of four optocouplers are required. Patent CN117894664A proposes to use three optocouplers for control, but its gate voltage is taken from the high drift tube voltage divider, so the current is small when it is turned on, and it is impossible to achieve fast switching off, and the isolation is low. Summary of the invention

[0004] In view of the above-mentioned defects or deficiencies in the prior art, it is expected to provide a high-voltage and high-speed ion gate pulse control circuit based on photoelectric isolation, which uses optical fiber and high-voltage isolation optocoupler to achieve complete electrical isolation of the system, realize rapid switching of the ion gate, and make the edge of the output pulse extremely steep, which can improve the detection sensitivity of the back-end system to a certain extent, improve the control effect of the ion gate, and expand the application field of ion mobility spectrometers.

[0005] The present invention provides a high-voltage and high-speed ion gate pulse control circuit based on photoelectric isolation, comprising an optical fiber signal input circuit, a drive circuit, an optical coupling circuit, a power supply circuit and a high-voltage DC power supply module;

[0006] The driving circuit comprises:

[0007] The first-stage driver U4 has its pins 1, 6, and 8 connected to the power supply circuit, its pin 2 connected to the optical fiber signal input circuit, and its pin 4 grounded;

[0008] A resistor R1, a first end of which is connected to a power supply circuit;

[0009] A resistor R3, a first end of which is connected to the power supply circuit, and a second end of which is connected to pin 3 of the primary driver U4;

[0010] A resistor R4, a first end of which is connected to the power supply circuit, and a second end of which is connected to pin 2 of the primary driver U4;

[0011] A resistor R2, a first end of which is connected to the second end of the resistor R1;

[0012] A resistor R10, a first end of which is connected to the 3rd pin of the primary driver U4, and a second end of which is connected to the 5th pin of the primary driver U4;

[0013] A capacitor C2, a first end of which is connected to the power supply circuit, and a second end of which is grounded; and

[0014] Capacitor C3, connected in parallel with capacitor C2;

[0015] The optocoupler circuit comprises:

[0016] The high-voltage isolation optocoupler U1 has its pin 2 connected to the second end of the resistor R2, its pin 3 connected to the pin 3 of the primary driver U4, and its pin 7 connected to the high-voltage DC power module;

[0017] A capacitor C1, a first end of which is connected to pin 7 of the high-voltage isolation optocoupler U1, and a second end of which is grounded; and

[0018] A resistor R7, a first end of which is connected to pin 5 of the high-voltage isolation optocoupler U1, and a second end of which is grounded;

[0019] The control circuit realizes fast closing and fast closing control of the ion gate based on the optical fiber signal and the high-voltage isolation optical coupler U1.

[0020] Furthermore, the optical fiber signal input circuit includes:

[0021] Optical fiber interface FC1, its pin 1 is connected to pin 2 of primary driver U4, its pin 2 is grounded, and its pin 3 is connected to the power supply circuit;

[0022] A resistor R6, a first end of which is connected to pin 1 of the optical fiber interface FC1, and a second end of which is connected to pin 4 of the optical fiber interface FC1;

[0023] The resistor R8 has a first end connected to pin 1 of the optical fiber interface FC1, and a second end connected to the power supply circuit.

[0024] Furthermore, the power supply circuit includes:

[0025] Isolation power module U8, its pins 1 and 2 are connected to the lithium battery, and its pin 5 is grounded;

[0026] The polarity capacitor C4 has its anode connected to pin 7 of the isolation power module U8 and its cathode connected to the ground;

[0027] Capacitor C5, connected in parallel with capacitor C4;

[0028] Furthermore, the driving circuit is connected to a TTL signal input circuit; a switch U3 is provided between the optical fiber signal input circuit and the driving circuit;

[0029] The TTL signal input circuit comprises:

[0030] BNC connector RF1;

[0031] Optocoupler U7, its pin 1 is connected to pin 1 of BNC connector RF1, and its pin 4 is connected to the power supply circuit;

[0032] A resistor R13, a first end of which is connected to pins 2, 3 and 4 of the BNC connector RF1;

[0033] A resistor R11, a first end of which is connected to the second end of the resistor R13, and a second end of which is connected to the pin 2 of the optocoupler U7;

[0034] The resistor R12 has a first end connected to pin 3 of the optocoupler U7;

[0035] A resistor R14, a first end of which is connected to the second end of the resistor R12, and a second end of which is grounded;

[0036] The switch U6 has its pin 1 connected to the pin 3 of the optocoupler U7, and its pin 2 connected to the pin 2 of the primary driver U4.

[0037] Furthermore, the output of the high-voltage DC power supply module is a DC voltage of 200 V.

[0038] Furthermore, the pin 2 of the primary driver U4 is connected to the anode of the light emitting diode LED2, the cathode of the light emitting diode LED2 is connected to the first end of the resistor R9, and the second end of the resistor R9 is grounded.

[0039] Furthermore, a first end of the 3-pin resistor R5 of the primary driver U4 and a second end of the resistor R5 are connected to the cathode of the light emitting diode LED1 , and an anode of the light emitting diode LED1 is connected between the resistor R1 and the resistor R2 .

[0040] Compared with the prior art, the beneficial effects of the present invention are:

[0041] The control circuit of the present invention is provided with a driving circuit and an optical coupling circuit; the pulse generator generates a pulse signal, which is connected to the optical fiber signal input circuit through an optical fiber, and then passes through the driving circuit to obtain a stronger driving capability, and then is isolated by the optical coupling circuit, so as to realize the complete electrical isolation of the system. The pulse signal is level-converted by the high-voltage isolation optical coupling. When the input is a high level, the high-voltage isolation optical coupling is turned on, and the voltage of the high-voltage DC power supply module is applied to both ends of the resistor R7. At this time, the potential of the gate Grid2 is higher than that of the gate Grid1, and an electric field in the opposite direction is formed between the two, and the ions are blocked and cannot pass through; when the input is a low level, the high-voltage isolation optical coupling is turned off, and the potential between the two gates is the same, and the ions can pass through normally.

[0042] The control circuit of the present application uses optical fiber and high-voltage isolation optical coupler to achieve complete electrical isolation of the system, realize rapid switching of the ion gate, and make the edge of the output pulse extremely steep. It can improve the detection sensitivity of the back-end system to a certain extent, improve the control effect of the ion gate, and expand the application field of the ion mobility spectrometer.

[0043] It should be understood that the contents described in the summary of the invention are not intended to limit the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0045] Figure 1 The circuit diagram is a high-voltage and high-speed ion gate pulse control circuit based on photoelectric isolation;

[0046] Figure 2 It is a regional schematic diagram of the ion gate;

[0047] Figure 3 Schematic diagram of the switching potential of the ion gate;

[0048] Figure 4 Schematic diagram of the output pulse edge of the control circuit under different resistance values ​​of resistor R7. DETAILED DESCRIPTION

[0049] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the relevant invention, rather than to limit the invention. It should also be noted that, for ease of description, only the parts related to the invention are shown in the accompanying drawings.

[0050] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0051] Please refer to Figure 1 to Figure 4 , an embodiment of the present invention provides a high-voltage and high-speed ion gate pulse control circuit based on photoelectric isolation, including an optical fiber signal input circuit, a drive circuit, an optical coupling circuit, a power supply circuit and a high-voltage DC power supply module;

[0052] The drive circuit includes:

[0053] The first-stage driver U4 has its pins 1, 6, and 8 connected to the power supply circuit, its pin 2 connected to the optical fiber signal input circuit, and its pin 4 grounded;

[0054] A resistor R1, a first end of which is connected to a power supply circuit;

[0055] A resistor R3, a first end of which is connected to the power supply circuit, and a second end of which is connected to pin 3 of the primary driver U4;

[0056] A resistor R4, a first end of which is connected to the power supply circuit, and a second end of which is connected to pin 2 of the primary driver U4;

[0057] A resistor R2, a first end of which is connected to the second end of the resistor R1;

[0058] A resistor R10, a first end of which is connected to the 3rd pin of the primary driver U4, and a second end of which is connected to the 5th pin of the primary driver U4;

[0059] A capacitor C2, a first end of which is connected to the power supply circuit, and a second end of which is grounded; and

[0060] Capacitor C3, connected in parallel with capacitor C2;

[0061] The optocoupler circuit includes:

[0062] The high-voltage isolation optocoupler U1 has its pin 2 connected to the second end of the resistor R2, its pin 3 connected to the pin 3 of the primary driver U4, and its pin 7 connected to the high-voltage DC power module;

[0063] A capacitor C1, a first end of which is connected to pin 7 of the high-voltage isolation optocoupler U1, and a second end of which is grounded; and

[0064] A resistor R7, a first end of which is connected to pin 5 of the high-voltage isolation optocoupler U1, and a second end of which is grounded;

[0065] The control circuit realizes fast closing and fast closing control of the ion gate based on the optical fiber signal and the high-voltage isolation optocoupler U1.

[0066] In this embodiment, when the ion gate is isolated and controlled, a pulse signal is first generated by a pulse generator, and the pulse signal enters the optical fiber signal input circuit through the optical fiber; then it passes through the primary driver U4 (SN75451) of the driving circuit to obtain a stronger driving capability, and then is isolated through the optocoupler circuit, thereby achieving complete electrical isolation of the system.

[0067] The pulse signal is level-converted through the high-voltage isolation optocoupler U1. When the input is at a high level, the high-voltage isolation optocoupler U1 is turned on, and the voltage of the high-voltage DC power supply module is applied to both ends of the resistor R7. At this time, the potential of the gate Grid2 of the ion gate is higher than that of the gate Grid1, and an electric field in the opposite direction is formed between the two, and the ions are blocked from passing through; when the input is at a low level, the high-voltage isolation optocoupler U1 is turned off, and the potential between the two gates Grid1 and Grid2 is the same, so the ions can pass through normally.

[0068] like Figure 2 As shown, taking the TP type ion gate as an example, the ion transfer tube is composed of the ionization source, ionization region, ion gate, drift region and ion receiver from left to right, and the ion gate is located between the ionization region and the drift region of the ion transfer tube; the ion gate is composed of three 0.1mm thick metal grids arranged in parallel and equidistantly, and the metal grids are Grid1, Grid2 and Grid3 from left to right. Among them, the metal grid Grid1 is well electrically connected to the last metal ring in the ionization region, and the potential is the same, which is the ion gate electrode 1; the metal grid Grid2 is the ion gate electrode 2; the metal grid GRID3 is well electrically connected to the first metal ring in the drift region, and the potential is the same, which is the ion gate electrode 3;

[0069] The ion gate electrode 1 and the ion gate electrode 2 are connected to the ion gate working voltage output 1 and the ion gate working voltage output 2 respectively; the ion gate works periodically, and each cycle has two states, namely, open and closed; when the ion gate is in the open state, the ion gate working voltage output 1 and the ion gate working voltage output 2 are electrically connected to the same point, and the voltage magnitudes are both the voltage at the position of the migration tube electrode where the ion gate is located. Since the voltage at this point is a floating voltage of approximately 7.5KV, it is necessary for the control circuit to have a high isolation withstand voltage value; when the ion gate is in the closed state, a voltage difference is controlled between the ion gate working voltage output 1 and the ion gate working voltage output 2, forming an electric field perpendicular to the direction of the axial drift electric field, so that ions cannot pass through the ion gate, wherein the voltage at the position of the migration tube electrode where the ion gate is located is the average voltage magnitude of the ion gate working voltage output 1 and the ion gate working voltage output 2.

[0070] The control circuit of the present application uses optical fiber and high-voltage isolation optocoupler U1 to achieve complete electrical isolation of the system, realize rapid switching of the ion gate, and make the edge of the output pulse extremely steep, which can improve the detection sensitivity of the back-end system to a certain extent, improve the control effect of the ion gate, and expand the application field of the ion mobility spectrometer.

[0071] In a preferred embodiment, if Figure 1 As shown, the optical fiber signal input circuit includes:

[0072] Optical fiber interface FC1, its pin 1 is connected to pin 2 of primary driver U4, its pin 2 is grounded, and its pin 3 is connected to the power supply circuit;

[0073] A resistor R6, a first end of which is connected to pin 1 of the optical fiber interface FC1, and a second end of which is connected to pin 4 of the optical fiber interface FC1;

[0074] The resistor R8 has a first end connected to pin 1 of the optical fiber interface FC1, and a second end connected to the power supply circuit.

[0075] In this embodiment, the optical fiber interface FC1 is connected to the pulse generator via an optical fiber, and the pulse signal generated by the pulse generator is introduced into the driving circuit via the optical fiber interface FC1, thereby ensuring complete electrical isolation of the system.

[0076] In a preferred embodiment, if Figure 1 As shown, the power supply circuit includes:

[0077] Isolation power module U8, its pins 1 and 2 are connected to the lithium battery, and its pin 5 is grounded;

[0078] The polarity capacitor C4 has its anode connected to pin 7 of the isolation power module U8 and its cathode connected to the ground;

[0079] Capacitor C5, connected in parallel with capacitor C4;

[0080] In this embodiment, the control circuit is powered by a lithium battery to ensure complete isolation from the mains. The lithium battery power supply voltage is 8V, which is converted to 12V and 5V through the isolation power module U8. The 12V voltage is supplied to the high-voltage DC power module, which is converted into DC high voltage to achieve ion gate control.

[0081] In a preferred embodiment, if Figure 1 As shown, the driving circuit is connected to a TTL signal input circuit; a switch U3 is provided between the optical fiber signal input circuit and the driving circuit;

[0082] The TTL signal input circuit includes:

[0083] BNC connector RF1;

[0084] Optocoupler U7, its pin 1 is connected to pin 1 of BNC connector RF1, and its pin 4 is connected to the power supply circuit;

[0085] A resistor R13, a first end of which is connected to pins 2, 3 and 4 of the BNC connector RF1;

[0086] A resistor R11, a first end of which is connected to the second end of the resistor R13, and a second end of which is connected to the pin 2 of the optocoupler U7;

[0087] The resistor R12 has a first end connected to pin 3 of the optocoupler U7;

[0088] A resistor R14, a first end of which is connected to the second end of the resistor R12, and a second end of which is grounded;

[0089] The switch U6 has its pin 1 connected to the pin 3 of the optocoupler U7, and its pin 2 connected to the pin 2 of the primary driver U4.

[0090] In this embodiment, the pulse generator is connected to the BNC connector RF1 through a conventional coaxial cable, and the pulse signal is introduced through the coaxial cable. By controlling the on-off of the switch U3 and the switch U6, the signal introduction switching between the optical fiber and the coaxial cable can be realized, thereby improving the applicability of the control circuit.

[0091] In a preferred embodiment, the output of the high voltage DC power supply module is a 200 V DC voltage, and when the 200 V DC voltage is loaded onto the resistor R7, the ion gate is closed.

[0092] In a preferred embodiment, if Figure 1 As shown, the pin 2 of the primary driver U4 is connected to the anode of the light emitting diode LED2, the cathode of the light emitting diode LED2 is connected to the first end of the resistor R9, and the second end of the resistor R9 is grounded.

[0093] In this embodiment, when a pulse signal is input into the driving circuit, the light emitting diode LED2 lights up, serving as a signal input prompt.

[0094] In a preferred embodiment, if Figure 1 As shown, the first end of the 3-pin resistor R5 of the primary driver U4, the second end of the resistor R5 is connected to the cathode of the light emitting diode LED1, and the anode of the light emitting diode LED1 is connected between the resistor R1 and the resistor R2.

[0095] In this embodiment, when the signal output by the primary driver U4 enters the high-voltage isolation optocoupler U1, the light-emitting diode LED1 lights up, serving as a signal output prompt.

[0096] In the description of this specification, the description of the terms "one embodiment", "some embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0097] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A high-voltage and high-speed ion gate pulse control circuit based on photoelectric isolation, characterized in that: It includes an optical fiber signal input circuit, a driving circuit, an optical coupling circuit, a power supply circuit and a high-voltage DC power supply module; The driving circuit comprises: The first-stage driver U4 has its pins 1, 6, and 8 connected to the power supply circuit, its pin 2 connected to the optical fiber signal input circuit, and its pin 4 grounded; A resistor R1, a first end of which is connected to a power supply circuit; A resistor R2, a first end of which is connected to the second end of the resistor R1; A resistor R3, a first end of which is connected to the power supply circuit, and a second end of which is connected to pin 3 of the primary driver U4; A resistor R4, a first end of which is connected to the power supply circuit, and a second end of which is connected to pin 2 of the primary driver U4; A resistor R10, a first end of which is connected to the 3rd pin of the primary driver U4, and a second end of which is connected to the 5th pin of the primary driver U4; A capacitor C2, a first end of which is connected to the power supply circuit, and a second end of which is grounded; and Capacitor C3, connected in parallel with capacitor C2; The optocoupler circuit comprises: The high-voltage isolation optocoupler U1 has its pin 2 connected to the second end of the resistor R2, its pin 3 connected to the pin 3 of the primary driver U4, and its pin 7 connected to the high-voltage DC power module; A capacitor C1, a first end of which is connected to pin 7 of the high-voltage isolation optocoupler U1, and a second end of which is grounded; and A resistor R7, a first end of which is connected to pin 5 of the high-voltage isolation optocoupler U1, and a second end of which is grounded; The control circuit realizes fast closing and fast closing control of the ion gate based on the optical fiber signal and the high-voltage isolation optical coupler U1.

2. The high-voltage and high-speed ion gate pulse control circuit based on photoelectric isolation according to claim 1 is characterized in that: The optical fiber signal input circuit comprises: Optical fiber interface FC1, its pin 1 is connected to pin 2 of primary driver U4, its pin 2 is grounded, and its pin 3 is connected to the power supply circuit; A resistor R6, a first end of which is connected to pin 1 of the optical fiber interface FC1, and a second end of which is connected to pin 4 of the optical fiber interface FC1; The resistor R8 has a first end connected to pin 1 of the optical fiber interface FC1, and a second end connected to the power supply circuit.

3. The high-voltage and high-speed ion gate pulse control circuit based on photoelectric isolation according to claim 1 is characterized in that: The power supply circuit comprises: Isolation power module U8, its pins 1 and 2 are connected to the lithium battery, and its pin 5 is grounded; The polarity capacitor C4 has its anode connected to pin 7 of the isolation power module U8 and its cathode connected to the ground; Capacitor C5 is connected in parallel with capacitor C4.

4. The high-voltage and high-speed ion gate pulse control circuit based on photoelectric isolation according to claim 1, characterized in that: The driving circuit is connected to a TTL signal input circuit; a switch U3 is provided between the optical fiber signal input circuit and the driving circuit; The TTL signal input circuit comprises: BNC connector RF1; Optocoupler U7, its pin 1 is connected to pin 1 of BNC connector RF1, and its pin 4 is connected to the power supply circuit; A resistor R13, a first end of which is connected to pins 2, 3 and 4 of the BNC connector RF1; A resistor R11, a first end of which is connected to the second end of the resistor R13, and a second end of which is connected to the pin 2 of the optocoupler U7; The resistor R12 has a first end connected to pin 3 of the optocoupler U7; A resistor R14, a first end of which is connected to the second end of the resistor R12, and a second end of which is grounded; The switch U6 has its pin 1 connected to the pin 3 of the optocoupler U7, and its pin 2 connected to the pin 2 of the primary driver U4.

5. The high-voltage and high-speed ion gate pulse control circuit based on photoelectric isolation according to claim 1, characterized in that: The output of the high voltage DC power supply module is 200V DC voltage.

6. The high-voltage and high-speed ion gate pulse control circuit based on photoelectric isolation according to claim 4, characterized in that: Pin 2 of the primary driver U4 is connected to the anode of the light emitting diode LED2, the cathode of the light emitting diode LED2 is connected to the first end of the resistor R9, and the second end of the resistor R9 is grounded.

7. The high-voltage and high-speed ion gate pulse control circuit based on photoelectric isolation according to any one of claims 1 or 4, characterized in that: A first end of the 3-pin resistor R5 of the primary driver U4 and a second end of the resistor R5 are connected to the cathode of the light emitting diode LED1 , and an anode of the light emitting diode LED1 is connected between the resistor R1 and the resistor R2 .

Images