Filament driving circuit and miniature radiation source

Abstract

The invention discloses a filament driving circuit and a miniature radiation source. The filament driving circuit comprises a boost driving module, a filament driving module, a boost module and a two-stage isolation transformer. The boost driving module is used for outputting a first boost driving signal and a second boost driving signal according to the boost modulation signal; the boosting module is used for outputting negative high voltage to the filament according to the first boosting driving signal and the second boosting driving signal; the filament driving module is used for outputting a filament control signal according to the first modulation signal and the second modulation signal; wherein the frequency of the second modulation signal is greater than that of the first modulation signal; the two-stage isolation transformer is used for transmitting the filament control signal to the filament and isolating the negative high voltage and the filament control signal. According to the filament driving circuit provided by the invention, the filament control signal and the negative high voltage are electrically isolated through the high-frequency two-stage isolation transformer, so that the high voltage resistance, the anti-interference capability and the safety of the circuit are improved, and the size of the circuit is also reduced.

Description

Technical Field

[0001] This invention relates to the field of filament driving technology, and in particular to a filament driving circuit and a miniature radiation source. Background Technology

[0002] Currently, miniature X-ray sources are widely used in various industrial environments due to their extremely high energy density. The filament heating power supply of the miniature X-ray source provides heating current to the cathode filament, causing the cathode filament to heat up, resulting in the escape of electrons from its surface. The cathode filament is then suspended above a negative high voltage, and the accelerating electric field provides energy to the electrons. Under the influence of the electric field force, the electrons rapidly collide with the target material.

[0003] Because the cathode filament has a strongly negative potential, a large number of resistors need to be connected in series in a certain proportion to reduce the voltage during the entire closed-loop control process. This not only increases the size of the miniature X-ray source, but also generates unnecessary heat during operation due to the voltage division of the resistors, and has poor anti-interference capability. Furthermore, since the entire circuit is generated in a high-voltage closed loop, if a short circuit occurs in the resistors, the corresponding high voltage flowing into the control terminal can cause a safety accident and damage the components.

[0004] Existing miniature radiation sources suffer from low safety and poor anti-interference capabilities, which have become urgent technical problems to be solved in the industry. Summary of the Invention

[0005] This invention provides a filament driving circuit and a miniature radiation source to solve the problems of low safety and poor anti-interference ability of existing miniature radiation sources.

[0006] According to one aspect of the present invention, a filament driving circuit is provided, comprising: a boost driving module, a filament driving module, a boost module, and a two-stage isolation transformer;

[0007] The input terminal of the boost driver module is connected to the boost modulation signal, the first output terminal of the boost driver module is connected to the first input terminal of the boost module, and the second output terminal of the boost driver module is connected to the second input terminal of the boost module. The boost driver module is used to output a first boost driver signal and a second boost driver signal according to the boost modulation signal.

[0008] The output terminal of the boost module is connected to the filament, and the boost module is used to output a negative high voltage to the filament according to the first boost drive signal and the second boost drive signal.

[0009] The first input terminal of the filament driving module is connected to a first modulation signal, the second input terminal of the filament driving module is connected to a second modulation signal, and the output terminal of the filament driving module is connected to the primary side of the two-stage isolation transformer; the filament driving module is used to output a filament control signal according to the first modulation signal and the second modulation signal; wherein, the frequency of the second modulation signal is greater than the frequency of the first modulation signal;

[0010] The secondary side of the double-stage isolation transformer is connected to the filament. The double-stage isolation transformer is used to transmit the filament control signal to the filament and isolate the negative high voltage and the filament control signal.

[0011] Optionally, the boost drive module includes a first boost drive unit, an inverting unit, and a second boost drive unit;

[0012] The input terminal of the first boost drive unit is connected to the boost modulation signal, and the output terminal of the first boost drive unit is connected to the first input terminal of the boost module; the first boost drive unit is used to output a first boost drive signal according to the boost modulation signal;

[0013] The first terminal of the inverting unit is connected to the boost modulation signal, and the second terminal of the inverting unit is connected to the input terminal of the second boost driving unit. The inverting unit is used to invert the boost modulation signal.

[0014] The output terminal of the second boost drive unit is connected to the second input terminal of the boost module; the second boost drive unit is used to output a second boost drive signal according to the inverted boost modulation signal.

[0015] Optionally, the filament driving module includes a first filament driving unit and a second filament driving unit; the input terminal of the first filament driving unit serves as the first input terminal of the filament driving module and is connected to the first modulation signal; the output terminal of the first filament driving unit is connected to the second input terminal of the second filament driving unit; the first filament driving unit is used to chop the power supply voltage according to the first modulation signal.

[0016] The first input terminal of the second filament driving unit serves as the second input terminal of the filament driving module, and is connected to the second modulation signal. The first output terminal of the second filament driving unit is connected to the first terminal of the primary side of the double-stage isolation transformer, and the second output terminal of the second filament driving unit is connected to the second terminal of the primary side of the double-stage isolation transformer. The second filament driving unit is used to output a filament control signal according to the second modulation signal and the power supply voltage after chopping.

[0017] Optionally, the boost module includes a high-voltage transformer and multiple cascaded boost units;

[0018] The first end of the primary side of the high-voltage transformer is connected to the output end of the first boost drive unit, and the second end of the primary side of the high-voltage transformer is connected to the output end of the second boost drive unit; the high-voltage transformer is used to boost the first boost drive signal and the second boost drive signal.

[0019] The first input terminal of the first-stage boost unit is connected to the first terminal of the secondary side of the high-voltage transformer, and the second input terminal of the first-stage boost unit is connected to the second terminal of the secondary side of the high-voltage transformer; the first output terminal of the first-stage boost unit is connected to the first input terminal of the second-stage boost unit, and the second output terminal of the first-stage boost unit is connected to the second input terminal of the second-stage boost unit.

[0020] The first input terminal of the k-th stage boost unit is connected to the first output terminal of the (k-1)-th stage boost unit, the second input terminal of the k-th stage boost unit is connected to the second output terminal of the (k-1)-th stage boost unit, and both the first and second output terminals of the k-th stage boost unit are connected to the filament; where k is an integer greater than or equal to 2.

[0021] Optionally, the boost unit includes a first capacitor, a second capacitor, a first diode, and a second diode;

[0022] The first terminal of the first capacitor is connected to the first terminal of the secondary side of the high voltage transformer, the second terminal of the first capacitor is connected to the anode of the first diode, and the cathode of the first diode is connected to the second terminal of the secondary side of the high voltage transformer.

[0023] The first terminal of the second capacitor is connected to the cathode of the first diode, the second terminal of the second capacitor is connected to the anode of the second diode, and the cathode of the second diode is connected to the anode of the first diode; the cathode of the second diode serves as the first output terminal of the boost unit, and the anode of the second diode serves as the second output terminal of the boost unit.

[0024] Optionally, the two-stage isolation transformer includes a first high-frequency transformer and a second high-frequency transformer;

[0025] The first terminal of the primary side of the first high-frequency transformer is connected to the first output terminal of the second filament driving unit, the second terminal of the primary side of the first high-frequency transformer is connected to the second output terminal of the second filament driving unit, the first terminal of the secondary side of the first high-frequency transformer is connected to the second output terminal of the nth stage boost unit, and the second terminal of the secondary side of the first high-frequency transformer is connected to the second terminal of the primary side of the second high-frequency transformer; wherein, when k is even, n equals k / 2; when k is odd, n equals (k-1) / 2;

[0026] The first end of the primary side of the second high-frequency transformer is connected to the first end of the secondary side of the first high-frequency transformer, the first end of the secondary side of the second high-frequency transformer is connected to the second output end of the k-th stage boost unit, and the second end of the secondary side of the second high-frequency transformer is connected to the filament.

[0027] Optionally, the filament driving circuit further includes a control module and a voltage sampling module;

[0028] The first output terminal of the control module is connected to the input terminal of the boost drive module, the second output terminal of the control module is connected to the first input terminal of the filament drive module, the third output terminal of the control module is connected to the second input terminal of the filament drive module, and the first input terminal of the control module is connected to the output terminal of the voltage sampling module; the control module is used to output the boost modulation signal, the first modulation signal, and the second modulation signal;

[0029] The input terminal of the voltage sampling module is connected to the output terminal of the boost module; the voltage sampling module is used to detect the negative high voltage output by the boost module and output a voltage sampling signal.

[0030] Optionally, the filament driving circuit further includes a current sampling module;

[0031] The first end of the current sampling module is connected to the output end of the filament drive module, the second end of the current sampling module is connected to the primary side of the double-stage isolation transformer, and the output end of the current sampling module is connected to the second input end of the control module. The current sampling module is used to detect the current information of the filament control signal output by the filament drive module and output a current sampling signal.

[0032] Optionally, the control module is further configured to adjust the boost modulation signal according to the voltage sampling signal; and to adjust the second modulation signal according to the current sampling signal.

[0033] According to another aspect of the present invention, a miniature radiation source is provided, comprising the filament driving circuit described above.

[0034] The technical solution of this invention involves a boost module controlling a boost drive module to boost the voltage. The boost module outputs a negative high voltage to the filament to form a high-voltage magnetic field. A filament control signal is output through a filament drive module, and a two-stage isolation transformer transmits this signal to the filament via magnetic field coupling, heating the filament and generating free electrons. The two-stage isolation transformer electrically isolates the filament control signal from the negative high voltage, improving the circuit's high-voltage withstand capability and anti-interference ability, increasing circuit safety, and effectively isolating the negative high voltage to prevent high voltage from flowing into the control terminal and damaging the circuit. Furthermore, the two-stage isolation transformer is a high-frequency transformer with a smaller core size, thus reducing the size of the miniature radiation source and improving its portability and compatibility.

[0035] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a schematic diagram of a filament driving circuit provided in an embodiment of the present invention;

[0038] Figure 2 This is a schematic diagram of another filament driving circuit provided in an embodiment of the present invention;

[0039] Figure 3 This is a schematic diagram of a boost drive module provided in an embodiment of the present invention;

[0040] Figure 4 This is a schematic diagram of another filament driving circuit provided in an embodiment of the present invention;

[0041] Figure 5 This is a schematic diagram of the structure of a filament driving module provided in an embodiment of the present invention;

[0042] Figure 6 This is a schematic diagram of another filament driving circuit provided in an embodiment of the present invention;

[0043] Figure 7 This is a schematic diagram of another filament driving circuit provided in an embodiment of the present invention;

[0044] Figure 8 This is a schematic diagram of another filament driving circuit provided in an embodiment of the present invention. Detailed Implementation

[0045] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0046] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0047] Figure 1 This is a schematic diagram of a filament driving circuit provided in an embodiment of the present invention. See also... Figure 1The filament drive circuit 100 includes a boost drive module 10, a filament drive module 20, a boost module 30, and a two-stage isolation transformer 40. The input terminal of the boost drive module 10 is connected to a boost modulation signal P1. The first output terminal of the boost drive module 10 is connected to the first input terminal of the boost module 30, and the second output terminal of the boost drive module 10 is connected to the second input terminal of the boost module 30. The boost drive module 30 is used to output a first boost drive signal and a second boost drive signal according to the boost modulation signal P1. The output terminal of the boost module 30 is connected to the filament 50, and the boost module 30 is used to output a first boost drive signal and a second boost drive signal according to the first boost drive signal and the second boost drive signal. A negative high voltage is output to the filament 50; the first input terminal of the filament driver module 20 is connected to the first modulation signal Q1, the second input terminal of the filament driver module 20 is connected to the second modulation signal Q2, and the output terminal of the filament driver module 20 is connected to the primary side of the double-stage isolation transformer 40; the filament driver module 20 is used to output a filament control signal according to the first modulation signal Q1 and the second modulation signal Q2; wherein, the frequency of the second modulation signal Q2 is greater than the frequency of the first modulation signal Q1; the secondary side of the double-stage isolation transformer 40 is connected to the filament 50, and the double-stage isolation transformer 40 is used to transmit the filament control signal to the filament 50 and isolate the negative high voltage and the filament control signal.

[0048] Specifically, the filament 50 not only requires current control for heating, causing the electrons on its surface to acquire work function and enter a state ready for emission, but also needs a negative high voltage to provide a high-voltage electric field for the emitted electrons, causing them to move rapidly under the influence of the electric field force. The magnitude of the heating current of the filament 50 determines its heating state and affects the number of free electrons. The filament 50 is connected to the negative high voltage, which provides a high-voltage electric field to the filament 50. The negative high voltage directly affects the strength of the electric field, thereby affecting the energy of the radiation. The boost drive module 10 in the filament drive circuit 100 provided in this embodiment of the invention can generate a first boost drive signal and a second boost drive signal based on the received boost modulation signal P1. The boost modulation signal P1 can be a square wave signal with variable pulse width. The boost drive module 10 is connected to the boost module 30. The boost drive module 10 outputs a first boost drive signal and a second boost drive signal to the boost module 30. The boost module 30 boosts the received first and second boost drive signals to a negative high voltage suitable for the filament 50. The output terminal of the boost module 30 is connected to one end of the filament 50 to provide a negative high voltage for the filament 50. The filament drive module 20 receives a first modulation signal Q1 and a second modulation signal Q2. The filament drive module 20 outputs a filament control signal to the double-stage isolation transformer 40 based on the first modulation signal Q1 and the second modulation signal Q2. The first modulation signal Q1 can be a square wave signal with a variable pulse width, and the second modulation signal Q2 is a high-frequency square wave signal. The frequency of the second modulation signal Q2 needs to be higher than the frequency of the first modulation signal Q1. Under the modulation of the high-frequency second modulation signal Q2, the output filament control signal has the same frequency as the second modulation signal Q2. The filament control signal is transmitted to the filament 50 through magnetic coupling via the double-stage isolation transformer 40. The filament control signal heats the filament 50, causing electrons to escape from it. These free electrons then rapidly move towards the target material under the influence of the high-voltage electric field generated by the negative high voltage. A double-stage isolation transformer 40 isolates the negative high voltage output from the boost module 30 from the filament control signal output from the filament drive module 20. The double-stage isolation transformer 40 can be a high-frequency transformer wound with nickel-zinc ferrite dual-hole magnetic beads. It not only transmits the filament control signal to the filament 50 via magnetic field coupling but also isolates the negative high voltage from the filament control signal. Because the double-stage isolation transformer 40 is a high-frequency transformer, the cross-sectional area of ​​the transformer core is significantly reduced, thus decreasing the circuit size.

[0049] The filament driving circuit provided in this embodiment of the invention uses a boost module to control a boost module to boost the voltage. The boost module outputs a negative high voltage to the filament to form a high-voltage magnetic field. The filament driving module outputs a filament control signal, which is transmitted to the filament via a two-stage isolation transformer using magnetic field coupling. This heats the filament, causing it to generate free electrons. The two-stage isolation transformer electrically isolates the filament control signal from the negative high voltage, improving the circuit's high-voltage withstand capability and anti-interference ability, increasing circuit safety, and effectively isolating the negative high voltage to prevent high voltage from flowing into the control terminal and damaging the circuit. Furthermore, the two-stage isolation transformer is a high-frequency transformer with a smaller core size, thus reducing the size of the miniature radiation source and improving its portability and compatibility.

[0050] Optional, Figure 2 This is a schematic diagram of another filament driving circuit provided in an embodiment of the present invention. Figure 3 This is a schematic diagram of a boost drive module provided in an embodiment of the present invention. Based on the above embodiments, see [link to other embodiments]. Figure 2 and Figure 3 The boost drive module 10 includes a first boost drive unit 11, an inverting unit 12, and a second boost drive unit 13. The input terminal of the first boost drive unit 11 is connected to the boost modulation signal P1, and the output terminal of the first boost drive unit 11 is connected to the first input terminal of the boost module 30. The first boost drive unit 11 is used to output a first boost drive signal according to the boost modulation signal P1. The first terminal of the inverting unit 12 is connected to the boost modulation signal P1, and the second terminal of the inverting unit 12 is connected to the input terminal of the second boost drive unit 13. The inverting unit 12 is used to invert the boost modulation signal P1. The output terminal of the second boost drive unit 13 is connected to the second input terminal of the boost module 30. The second boost drive unit 13 is used to output a second boost drive signal according to the inverted boost modulation signal P1.

[0051] Specifically, after receiving the boost modulation signal P1, the first boost drive unit 11 outputs a first boost drive signal to the first input of the boost module 30 based on the boost modulation signal P1. The input of the inverting unit 12 is also connected to the boost modulation signal P1. The inverting unit 12 is mainly used to invert the boost modulation signal P1 and output the inverted boost modulation signal P1 to the second boost drive unit 13. The second boost drive unit 13 outputs a second boost drive signal based on the inverted boost modulation signal P1. The first boost drive unit 11 and the second boost drive unit 13 have the same structure. Since the received boost modulation signal P1 has opposite phases, the output first boost drive signal and second boost drive signal have opposite phases.

[0052] For details, see Figure 3 The first boost drive unit 11 includes a first gate control chip 111, capacitors C1, C2, C3, and C4, as well as diodes D1, D2, and D3. Diode D1 is connected in series between pins 1 and 4 of the first gate control chip 111, and pin 4 of the first gate control chip 111 is also connected to the power supply voltage VCC. Pin 2 of the first gate control chip 111 receives the boost modulation signal P1, pin 8 of the first gate control chip 111 is connected to the control terminal of the switch D2, pin 5 of the first gate control chip 111 is connected to the control terminal of the switch D3, pin 6 of the first gate control chip 111 is grounded, and pin 7 of the first gate control chip 111 is connected to the second terminal of the switch D2 and the first terminal of the switch D3, respectively, and outputs the first boost drive signal through the parallel capacitors C3 and C4. Pin 3 of the first gate control chip 111 of the first boost drive unit 11 is connected to pin 3 of the second gate control chip 131 of the second boost drive unit 13. The second boost drive unit 13 includes a second gate control chip 131, capacitors C5, C6, C7, and C8, as well as diodes D4, and switching transistors D5 and D6. Diode D4 is connected in series between pins 1 and 4 of the second gate control chip 131. Pin 2 of the second gate control chip 131 is connected to output pin 4 of the inverting unit 12. Pin 8 of the second gate control chip 131 is connected to the control terminal of switching transistor D5. Pin 5 of the second gate control chip 131 is connected to the control terminal of switching transistor D6. Pin 6 of the second gate control chip 131 is grounded. Pin 7 of the second gate control chip 131 is connected to the second terminal of switching transistor D5 and the first terminal of switching transistor D6, respectively. The second boost drive signal is output through parallel capacitors C7 and C8. Pin 2 of the inverting unit 12 is connected to the boost modulation signal P1. Pin 1 of the inverting unit 12 is left floating. Pin 3 of the inverting unit 12 is grounded. Pin 5 of the inverting unit 12 is connected to the power supply voltage VCC. The first gate control chip 111 is mainly used to control the states of switching transistors D2 and D3 to output a first boost drive signal. The second gate control chip 131 is mainly used to control the states of switching transistors D5 and D6 to output a second boost drive signal. For example, the first gate control chip 111 and the second gate control chip 131 can be ADP3120AJCPZ-RL type chips.

[0053] Optional, Figure 4 This is a schematic diagram of another filament driving circuit provided in an embodiment of the present invention. Figure 5 This is a schematic diagram of a filament driving module provided in an embodiment of the present invention. Based on the above embodiments, see [link to other embodiments]. Figure 4 and Figure 5The filament driving module 20 includes a first filament driving unit 21 and a second filament driving unit 22. The input terminal of the first filament driving unit 21 serves as the first input terminal of the filament driving module 20, receiving a first modulation signal Q1. The output terminal of the first filament driving unit 21 is connected to the second input terminal of the second filament driving unit 22. The first filament driving unit 21 is used to chop the power supply voltage VCC according to the first modulation signal Q1. The first input terminal of the second filament driving unit 22 serves as the second input terminal of the filament driving module 20, receiving a second modulation signal Q2. The first output terminal of the second filament driving unit 22 is connected to the first terminal of the primary side of the double-stage isolation transformer 40, and the second output terminal of the second filament driving unit 22 is connected to the second terminal of the primary side of the double-stage isolation transformer 40. The second filament driving unit 22 is used to output a filament control signal according to the second modulation signal Q2 and the chopped power supply voltage VCC.

[0054] Specifically, the input terminal of the first filament driver unit 21 receives the first modulation signal Q1. After receiving the first modulation signal Q1, the first filament driver unit 21 performs chopping and smoothing processing on the power supply voltage VCC according to the first modulation signal Q1. The output voltage after processing is within 2V-9V. The output terminal of the first filament driver unit 21 is connected to the second input terminal of the second filament driver unit 22, and outputs the chopped and smoothed voltage to the second filament driver unit 22. The first input terminal of the second filament driver unit 21 receives the second modulation signal Q2. The second filament driver unit 22 is mainly used to output filament control signals according to the second modulation signal Q2. The second modulation signal Q2 can be a high-frequency square wave signal. Under the action of the second modulation signal Q2, the second filament driver unit 22 modulates the voltage output by the first filament driver unit 21 into a high-frequency pulsating square wave, and then outputs it to the double-stage isolation transformer 40. Among them, the first modulation signal Q1 can be a square wave signal with variable pulse width, the second modulation signal Q2 can be a high-frequency square wave signal, and the filament adjustment signal can be a high-frequency pulsating square wave. For example, the second modulation signal Q2 can be a high-frequency square wave signal with a frequency of 20MHz, and the output filament adjustment signal can be a high-frequency pulsating square wave with a frequency of 20MHz.

[0055] The first filament driving unit 21 includes a third gate control chip 211, capacitors C9 and C10, diode D7, switching transistors D8 and D9, and inductor L1. Diode D7 is connected in series between pins 1 and 4 of the third gate control chip 211, and pin 4 of the third gate control chip 211 is also connected to the power supply voltage VCC. Pin 2 of the third gate control chip 211 receives the first modulation signal Q1. Pin 8 of the third gate control chip 211 is connected to the control terminal of switching transistor D8, pin 5 of the third gate control chip 211 is connected to the control terminal of switching transistor D9, pin 7 of the third gate control chip 211 is connected to the second terminal of switching transistor D8 and the first terminal of switching transistor D9, and outputs the chopped and smoothed power supply voltage through inductor L1. Pin 6 of the third gate control chip 211 is grounded. The second filament driving circuit 22 includes a driver chip 221, capacitors C11, C12, and C13, resistors R1, R2, and R3, and a switching transistor D10. Pin 1 of the driver chip 221 is connected to the output terminal of the first filament driving unit 21. Pin 4 of the driver chip 221 is connected to the power supply voltage VCC. Pin 2 of the driver chip 221 is connected to the power supply voltage VCC through the first resistor R1. Pin 8 of the driver chip 221 outputs the filament control signal through capacitor C12. Pin 7 of the driver chip 221 is connected to the double-stage isolation transformer 40 through resistor R3. Pin 2 of the driver chip 221 serves as the second input terminal of the filament driving module 20, receiving the second modulation signal Q2. Pins 5 and 6 of the driver chip 221 are grounded. The third gate control chip 211 controls switching transistors D8 and D9 to chop the power supply voltage according to the first modulation signal Q1, and the driver chip 211 modulates the chopped power supply voltage into a high-frequency pulsating square wave according to the second modulation signal Q2. For example, the third gate control chip 211 can be an ADP3120AJCPZ-RL model chip, and the driver chip 211 can be an FL7158ISZ model chip.

[0056] Optional, Figure 6 This is a schematic diagram of another filament driving circuit provided in an embodiment of the present invention. Based on the above embodiments, see [link to other embodiments]. Figure 6The boost module 30 includes a high-voltage transformer 31 and multiple cascaded boost units 32; the first terminal of the primary side of the high-voltage transformer 31 is connected to the output terminal of the first boost drive unit 11, and the second terminal of the primary side of the high-voltage transformer 31 is connected to the output terminal of the second boost drive unit 13; the high-voltage transformer 31 is used to boost the first boost drive signal and the second boost drive signal; the first input terminal of the first-stage boost unit 32-1 is connected to the first terminal of the secondary side of the high-voltage transformer 31, and the second input terminal of the first-stage boost unit 32-1 is connected to the second terminal of the secondary side of the high-voltage transformer 31; the first-stage boost unit 32- The first output terminal of the first stage boost unit 32-1 is connected to the first input terminal of the second stage boost unit 32-2, and the second output terminal of the first stage boost unit 32-1 is connected to the second input terminal of the second stage boost unit 32-2; the first input terminal of the k-th stage boost unit 32-k is connected to the first output terminal of the (k-1)-th stage boost unit 32-(k-1), and the second input terminal of the k-th stage boost unit 32-k is connected to the second output terminal of the (k-1)-th stage boost unit 32-(k-1); the first and second output terminals of the k-th stage boost unit 32-k are both connected to the filament; where k is an integer greater than or equal to 2.

[0057] Specifically, the first and second input terminals of the high-voltage transformer 31 receive the first boost drive signal and the second boost drive signal, respectively. The high-voltage transformer 31 mainly boosts the first and second boost drive signals, which are in opposite phase. The turns ratio of the high-voltage transformer 31 can be 1:200, which can amplify the voltage on the primary side by 200 times. The boost unit 32 is mainly used to further boost the voltage boosted by the high-voltage transformer 31 and output a negative high voltage to the filament 50. The boost module 30 can include multiple cascaded boost units 32, each of which can double the voltage. The first-stage boost unit 32-1 is connected to the high-voltage transformer 31 and is used to further boost the voltage boosted by the high-voltage transformer 31. The second-stage boost unit 32-2 is connected to the first-stage boost unit 32-1 and is used to perform a secondary boost on the voltage boosted by the first-stage boost unit 32-1. The boost unit 32 may include k boost units 32, which can further amplify the voltage boosted by the high voltage transformer 31 by a factor of k. The output terminal of the k-th boost unit 32-k outputs a negative high voltage to the filament 50. The number of boost units 32 is not specifically limited in this invention and can be set according to actual needs.

[0058] Optionally, based on the above embodiments, see also... Figure 6The boost unit 32 includes a first capacitor C14, a second capacitor C15, a first diode D11, and a second diode D12. The first terminal of the first capacitor C14 is connected to the first terminal of the secondary side of the high-voltage transformer 31, and the second terminal of the first capacitor C14 is connected to the anode of the first diode D11. The cathode of the first diode D11 is connected to the second terminal of the secondary side of the high-voltage transformer 31. The first terminal of the second capacitor C15 is connected to the cathode of the first diode D11, and the second terminal of the second capacitor C15 is connected to the anode of the second diode D12. The cathode of the second diode D12 is connected to the anode of the first diode D11. The cathode of the second diode D12 serves as the first output terminal of the boost unit 30, and the anode of the second diode D12 serves as the second output terminal of the boost unit 30.

[0059] Specifically, in the first boost unit 32-1, the first terminal of the first capacitor C14-1 is connected to the first output terminal of the high-voltage transformer 31, and the second terminal of the first capacitor C14-1 is connected to the anode of the first diode D11-1 and the cathode of the second diode D12-1. In the first boost unit 32-1, the first terminal of the second capacitor C15-1 is connected to the second output terminal of the high-voltage transformer 31 and the cathode of the first diode D11-1, and the second terminal of the second capacitor C15-1 is connected to the anode of the second diode D12-1. In the second boost unit 32-2, the first terminal of the first capacitor C14-2 is connected to the cathode of the second diode D12-1 in the first boost unit 32-1, and the second terminal of the first capacitor C14-2 is connected to the anode of the first diode D11-2 and the cathode of the second diode D12-2. The first terminal of the second capacitor C15-2 in the second boost unit 32-2 is connected to the anode of the second diode D12-1 and the anode of the second diode D12-1 in the first boost unit 32-1, respectively. The second terminal of the second capacitor C15-2 is connected to the anode of the second diode D12-2. The second terminal of the first capacitor C14-(k-1) in the (k-1)th boost unit 32-(k-1) is connected to the anode of the first diode D11-(k-1) and the cathode of the second diode D12-(k-1), respectively. The first terminal of the second capacitor C15-(k-1) in the (k-1)th boost unit 32-(k-1) is connected to the cathode of the first diode D11-(k-1), and the second terminal of the second capacitor C15-1 in the (k-1)th boost unit 32-(k-1) is connected to the anode of the second diode D12-(k-1) and the cathode of the first diode D11-k in the k-th boost unit 32-k, respectively. The first terminal of the first capacitor C14-k in the k-th stage boost unit 32-k is connected to the cathode of the second diode D12-(k-1) in the (k-1)-th stage boost unit 32-(k-1). The second terminal of the first capacitor C14-k in the k-th stage boost unit 32-k is connected to the anode of the first diode D11-k and the cathode of the second diode D12-k, respectively. The first terminal of the second capacitor C15-k in the k-th stage boost unit 32-k is connected to the cathode of the first diode D11-k, and the second terminal of the second capacitor C15-k in the (k-1)-th stage boost unit 32-k is connected to the anode of the second diode D12-k. Both the cathode and anode of the second diode D12-k in the k-th stage boost unit 32-k are connected to the filament 50, providing a negative high voltage to the filament. The first boost drive signal and the second boost drive signal are out of phase and alternate, and the phase of the output voltage at the first and second output terminals of the high-voltage transformer 31 also alternates. Then, through the interaction of the first diode D11 and the second diode D12, a negative high voltage is generated at the second terminal of the second capacitor C15. Through the boosting effect of the multi-stage boost unit 32, the k-th stage boost unit outputs a negative high voltage suitable for the filament 50.

[0060] Optional, Figure 7 This is a schematic diagram of another filament driving circuit provided in an embodiment of the present invention. Based on the above embodiments, see below. Figure 7 The dual-stage isolation transformer 40 includes a first high-frequency transformer 41 and a second high-frequency transformer 42. The first terminal of the primary side of the first high-frequency transformer 41 is connected to the first output terminal of the second filament drive unit 22, the second terminal of the primary side of the first high-frequency transformer 41 is connected to the second output terminal of the second filament drive unit 22, the first terminal of the secondary side of the first high-frequency transformer 41 is connected to the second output terminal of the nth stage boost unit 32-n, and the second terminal of the secondary side of the first high-frequency transformer 41 is connected to the second terminal of the primary side of the second high-frequency transformer 42. Wherein, when k is even, n equals k / 2; when k is odd, n equals (k-1) / 2. The first terminal of the primary side of the second high-frequency transformer 42 is connected to the first terminal of the secondary side of the first high-frequency transformer 41, the first terminal of the secondary side of the second high-frequency transformer 42 is connected to the second output terminal of the kth stage boost unit 32-k, and the second terminal of the secondary side of the second high-frequency transformer 42 is connected to the filament 50.

[0061] Specifically, the primary side of the first high-frequency transformer 41 is connected to the first and second output terminals of the second filament drive unit 22. The first terminal of the secondary side of the first high-frequency transformer 41 is connected to the second output terminal of the nth stage boost unit 32-n. The nth stage boost unit 32-n includes a first capacitor C14-n and a second capacitor C15-n, as well as the anode of the first diode D11-n and the second diode D12-n. The first terminal of the secondary side of the first high-frequency transformer 41 is connected to the anode of the second diode D12-n. Wherein, when k is even, n equals k / 2; when k is odd, n equals (k-1) / 2 or n equals (k+1) / 2. The first terminal of the secondary side of the second high-frequency transformer 41 is connected to the second output terminal of the kth stage boost unit 32-k. The first high-frequency transformer 41 and the second high-frequency transformer 42 can distribute the negative high voltage output by the boost module 30 as evenly as possible, so that the voltage received by the first high-frequency transformer 41 and the second high-frequency transformer 42 is almost the same, improving the voltage withstand capability of the circuit and avoiding damage to the transformer. The filament control signal is transmitted to the filament 50 via magnetic field coupling through the first high-frequency transformer 41 and the second high-frequency transformer 42. The turns ratio of the first high-frequency transformer 41 and the second high-frequency transformer 42 is not specifically limited in this embodiment of the invention. For example, the turns ratio of the first high-frequency transformer 41 can be 1:1, and the turns ratio of the second high-frequency transformer 42 can be 1:2.

[0062] Optional, Figure 8This is a schematic diagram of another filament driving circuit provided in an embodiment of the present invention. Based on the above embodiments, see below. Figure 8 The filament drive circuit 100 also includes a control module 60 and a voltage sampling module 70; the first output terminal of the control module 60 is connected to the input terminal of the boost drive module 10, the second output terminal of the control module 60 is connected to the first input terminal of the filament drive module 20, the third output terminal of the control module 60 is connected to the second input terminal of the filament drive module 20, and the first input terminal of the control module 60 is connected to the output terminal of the voltage sampling module 70; the control module 60 is used to output a boost modulation signal P1, a first modulation signal Q1, and a second modulation signal Q2; the input terminal of the voltage sampling module 70 is connected to the output terminal of the boost module 30; the voltage sampling module 70 is used to detect the negative high voltage output by the boost module 30 and output a voltage sampling signal.

[0063] Specifically, the voltage sampling module 70 in the filament drive circuit 100 samples the negative high voltage output by the boost module 30 and transmits the sampled voltage signal to the control module 60. The voltage sampling module 70 may include multiple resistors, filter capacitors, and operational amplifiers connected in series. The control module 60 is mainly used to output a boost modulation signal P1 to the boost drive module 10 and a first modulation signal Q1 and a second modulation signal Q2 to the filament drive module 20. The control module 60 can be a microcontroller, a programmable logic controller, or a host computer.

[0064] Optionally, based on the above embodiments, see also... Figure 8 The filament drive circuit 100 also includes a current sampling module 80; the first end of the current sampling module 80 is connected to the output end of the filament drive module 20, the second end of the current sampling module 80 is connected to the primary side of the double-stage isolation transformer 40, and the output end of the current sampling module 80 is connected to the second input end of the control module 60; the current sampling module 80 is used to detect the current information of the filament control signal output by the filament drive module 20 and output a current sampling signal.

[0065] Specifically, the filament drive circuit 100 also includes a current sampling module 80. The current sampling module 80 is mainly connected in series between the second filament drive unit 22 and the first high-frequency transformer 41. It is primarily used to sample the current of the filament control signal output by the second filament drive unit 22, obtain the current information of the filament control signal for heating the filament 50, and output the current sampling signal to the control module 60. The current sampling module 80 may include a current sampling resistor and a current detection chip, etc.

[0066] Optionally, based on the above embodiments, see also... Figure 8The control module 60 is also used to adjust the boost modulation signal P1 according to the voltage sampling signal; and to adjust the second modulation signal Q2 according to the current sampling signal.

[0067] Specifically, the first and second input terminals of the control module 60 are connected to the voltage sampling module 70 and the current sampling module 80, respectively, to receive voltage and current sampling signals. After receiving the voltage sampling signal, the control module 60 can adjust the boost modulation signal P1 in real time according to the voltage sampling signal, thereby achieving closed-loop control of the boost module 30 to output a negative high voltage. The control module 60 can also adjust the second modulation signal Q2 in real time according to the current sampling signal to achieve closed-loop control of the filament heating current.

[0068] The filament driving circuit provided by this invention electrically isolates the filament control signal from the negative high voltage through a two-stage high-frequency isolation transformer, improving the circuit's high voltage resistance and anti-interference capability, enhancing circuit safety. By using voltage sampling modules and current sampling modules for voltage and current feedback, closed-loop control of the filament can be achieved, which can quickly adjust the heating current of the negative high voltage, improving circuit stability and response speed.

[0069] This invention also provides a miniature radiation source, which includes the filament driving circuit provided in any of the above embodiments. Since the miniature radiation source provided in this invention includes the filament driving circuit provided in this invention, it also has the same beneficial effects, and will not be described again here.

[0070] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A filament driving circuit, characterized in that, include: Boost drive module, filament drive module, boost module, and two-stage isolation transformer; The input terminal of the boost driver module is connected to the boost modulation signal, the first output terminal of the boost driver module is connected to the first input terminal of the boost module, and the second output terminal of the boost driver module is connected to the second input terminal of the boost module. The boost driver module is used to output a first boost driver signal and a second boost driver signal according to the boost modulation signal. The output terminal of the boost module is connected to the filament, and the boost module is used to output a negative high voltage to the filament according to the first boost drive signal and the second boost drive signal. The first input terminal of the filament driving module is connected to a first modulation signal, the second input terminal of the filament driving module is connected to a second modulation signal, and the output terminal of the filament driving module is connected to the primary side of the two-stage isolation transformer; the filament driving module is used to output a filament control signal according to the first modulation signal and the second modulation signal; wherein, the frequency of the second modulation signal is greater than the frequency of the first modulation signal; The secondary side of the double-stage isolation transformer is connected to the filament. The double-stage isolation transformer is used to transmit the filament control signal to the filament and isolate the negative high voltage and the filament control signal.

2. The filament driving circuit according to claim 1, characterized in that, The boost drive module includes a first boost drive unit, an inverting unit, and a second boost drive unit; The input terminal of the first boost drive unit is connected to the boost modulation signal, and the output terminal of the first boost drive unit is connected to the first input terminal of the boost module; the first boost drive unit is used to output a first boost drive signal according to the boost modulation signal; The first terminal of the inverting unit is connected to the boost modulation signal, and the second terminal of the inverting unit is connected to the input terminal of the second boost driving unit. The inverting unit is used to invert the boost modulation signal. The output terminal of the second boost drive unit is connected to the second input terminal of the boost module; the second boost drive unit is used to output a second boost drive signal according to the inverted boost modulation signal.

3. The filament driving circuit according to claim 2, characterized in that, The filament driving module includes a first filament driving unit and a second filament driving unit; The input terminal of the first filament driving unit serves as the first input terminal of the filament driving module and is connected to the first modulation signal. The output terminal of the first filament driving unit is connected to the second input terminal of the second filament driving unit. The first filament driving unit is used to chop the power supply voltage according to the first modulation signal; The first input terminal of the second filament driving unit serves as the second input terminal of the filament driving module and is connected to the second modulation signal. The first output terminal of the second filament driving unit is connected to the first terminal of the primary side of the double-stage isolation transformer, and the second output terminal of the second filament driving unit is connected to the second terminal of the primary side of the double-stage isolation transformer. The second filament driving unit is used to output a filament control signal according to the second modulation signal and the power supply voltage after chopping.

4. The filament driving circuit according to claim 3, characterized in that, The boost module includes a high-voltage transformer and multiple cascaded boost units; The first end of the primary side of the high-voltage transformer is connected to the output end of the first boost drive unit, and the second end of the primary side of the high-voltage transformer is connected to the output end of the second boost drive unit; the high-voltage transformer is used to boost the first boost drive signal and the second boost drive signal. The first input terminal of the first-stage boost unit is connected to the first terminal of the secondary side of the high-voltage transformer, and the second input terminal of the first-stage boost unit is connected to the second terminal of the secondary side of the high-voltage transformer; the first output terminal of the first-stage boost unit is connected to the first input terminal of the second-stage boost unit, and the second output terminal of the first-stage boost unit is connected to the second input terminal of the second-stage boost unit. The first input terminal of the k-th stage boost unit is connected to the first output terminal of the (k-1)-th stage boost unit, the second input terminal of the k-th stage boost unit is connected to the second output terminal of the (k-1)-th stage boost unit, and both the first and second output terminals of the k-th stage boost unit are connected to the filament; where k is an integer greater than or equal to 2.

5. The filament driving circuit according to claim 4, characterized in that, The boost unit includes a first capacitor, a second capacitor, a first diode, and a second diode; The first terminal of the first capacitor is connected to the first terminal of the secondary side of the high voltage transformer, the second terminal of the first capacitor is connected to the anode of the first diode, and the cathode of the first diode is connected to the second terminal of the secondary side of the high voltage transformer. The first terminal of the second capacitor is connected to the cathode of the first diode, the second terminal of the second capacitor is connected to the anode of the second diode, and the cathode of the second diode is connected to the anode of the first diode; the cathode of the second diode serves as the first output terminal of the boost unit, and the anode of the second diode serves as the second output terminal of the boost unit.

6. The filament driving circuit according to claim 4, characterized in that, The dual-stage isolation transformer includes a first high-frequency transformer and a second high-frequency transformer; The first terminal of the primary side of the first high-frequency transformer is connected to the first output terminal of the second filament driving unit, and the second terminal of the primary side of the first high-frequency transformer is connected to the second output terminal of the second filament driving unit. The first terminal of the secondary side of the first high-frequency transformer is connected to the second output terminal of the nth stage boost unit, and the second terminal of the secondary side of the first high-frequency transformer is connected to the second terminal of the primary side of the second high-frequency transformer. Wherein, when k is even, n equals k / 2; when k is odd, n equals... The first end of the primary side of the second high-frequency transformer is connected to the first end of the secondary side of the first high-frequency transformer, the first end of the secondary side of the second high-frequency transformer is connected to the second output end of the k-th stage boost unit, and the second end of the secondary side of the second high-frequency transformer is connected to the filament.

7. The filament driving circuit according to claim 1, characterized in that, The filament driving circuit also includes a control module and a voltage sampling module; The first output terminal of the control module is connected to the input terminal of the boost drive module, the second output terminal of the control module is connected to the first input terminal of the filament drive module, the third output terminal of the control module is connected to the second input terminal of the filament drive module, and the first input terminal of the control module is connected to the output terminal of the voltage sampling module; the control module is used to output the boost modulation signal, the first modulation signal, and the second modulation signal; The input terminal of the voltage sampling module is connected to the output terminal of the boost module; the voltage sampling module is used to detect the negative high voltage output by the boost module and output a voltage sampling signal.

8. The filament driving circuit according to claim 7, characterized in that, The filament driving circuit also includes a current sampling module; The first end of the current sampling module is connected to the output end of the filament drive module, the second end of the current sampling module is connected to the primary side of the double-stage isolation transformer, and the output end of the current sampling module is connected to the second input end of the control module. The current sampling module is used to detect the current information of the filament control signal output by the filament drive module and output a current sampling signal.

9. The filament driving circuit according to claim 8, characterized in that, The control module is further configured to adjust the boost modulation signal according to the voltage sampling signal; and to adjust the second modulation signal according to the current sampling signal.

10. A miniature radiation source, characterized in that, Includes the filament driving circuit according to any one of claims 1-9.

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