A wide-range and high-precision medical X-ray imaging system

Abstract

The present invention discloses a medical X-ray imaging system with a wide measurement range and high precision. It includes a power supply circuit, an X-ray source, a tube current circuit, a tube voltage circuit, a current detection circuit, and a control circuit; the power supply circuit is respectively connected to the X-ray source and the control circuit; the tube current circuit is respectively connected to the X-ray source and the control circuit; the tube voltage circuit is respectively connected to the X-ray source and the control circuit; the current detection circuit is respectively connected to the tube current circuit and the control circuit, and is used for detecting the current of the X-ray source and providing a current feedback signal to the control circuit; the control circuit is used for receiving the current feedback signal of the current detection circuit and controlling the operation of the power supply circuit, the tube current circuit, and the tube voltage circuit. The present invention can meet the requirements of wide measurement range and high precision for current detection in the X-ray imaging system, and has the advantages of low cost, wide current measurement range, and high precision.

Description

Technical Field

[0001] The invention relates to an automatic material mixing and pressing device, in particular to a medical X-ray imaging system with a wide measurement range and high precision. Background Art

[0002] X-ray imaging devices are basic diagnostic equipment in modern medicine and can be widely used in the clinical diagnosis of chest, bone and joint, breast diseases, gallstones and urinary system diseases, digestive, respiratory, urinary and cardiovascular system diseases. Medical X-ray imaging systems have high requirements for the accuracy of current detection. If there is a lack of wide-range and high-precision current detection circuits, it may cause: 1. Fluctuation in imaging quality: the inability to accurately detect the X-ray tube current may cause instability in the intensity and penetration of X-rays, affecting the clarity of the image; 2. Decreased equipment durability: abnormal current fluctuations may accelerate the aging of the X-ray tube, increase the risk of failure and replacement costs. Therefore, wide-range and high-precision current detection circuits play a vital role in ensuring the stable operation of medical X-ray imaging systems and improving imaging quality. When faced with X-rays of different intensities, medical X-ray imaging systems require currents with a wide range. Existing medical X-ray imaging systems generally use signal conditioning circuits with a single amplification factor and DC bias. When the input current of this circuit is small, the voltage signal obtained after the bias, amplification and filtering of the signal conditioning circuit has a narrow variation range. The AD sampling quantization error and interference have a great influence on the current sampling accuracy, resulting in a large current error, and even the AD quantization error and interference can overwhelm the current signal value; when the input current is large, the voltage signal obtained after the bias, amplification and filtering of the signal conditioning circuit has a large variation range, resulting in output signal saturation or cutoff distortion, or causing the output signal to exceed the linear amplification range of the operational amplifier, or causing the output signal to exceed the optimal AD sampling range, greatly reducing the accuracy of current measurement. Summary of the invention

[0003] The purpose of the present invention is to provide a medical X-ray imaging system with a wide range and high precision. The present invention can meet the requirements of the X-ray imaging system for current detection with a wide range and high precision, and has the advantages of low cost, wide current measurement range and high precision.

[0004] Technical solution of the present invention: A wide-range and high-precision medical X-ray imaging system, comprising a power supply circuit, an X-ray source, a tube current circuit, a tube voltage circuit, a current detection circuit and a control circuit; the power supply circuit is respectively connected to the X-ray source and the control circuit, and the power supply circuit is used to provide a high-voltage power supply for the X-ray source; the tube current circuit is respectively connected to the X-ray source and the control circuit, and the tube current circuit is used to control the intensity and exposure time of the X-ray; the tube voltage circuit is respectively connected to the X-ray source and the control circuit, and the tube voltage circuit is used to control the acceleration energy of the X-ray source electrons and the energy of the X-ray; the current detection circuit is respectively connected to the tube current circuit and the control circuit, and the current detection circuit is used to detect the current of the X-ray source and provide a current feedback signal to the control circuit; the control circuit is used to receive the current feedback signal of the current detection circuit and control the operation of the power supply circuit, the tube current circuit and the tube voltage circuit;

[0005] The current detection circuit includes a current-to-voltage module, a high-precision DC bias module, an amplification module and a single-chip microcomputer control module; the single-chip microcomputer control module is respectively connected to the current-to-voltage module and the amplification module; the amplification module is respectively connected to the current-to-voltage module and the high-precision DC bias module.

[0006] For the above-mentioned wide-range and high-precision medical X-ray imaging system, the current-to-voltage module includes MOS transistors Q1, Q2, Q3 and Q4; the current-to-voltage module is connected in parallel with the tube voltage circuit; the drain of MOS transistor Q1 is respectively connected to the drains of MOS transistors Q2, Q3, Q4 and the amplification module; the gates of MOS transistors Q1, Q2, Q3 and Q4 are respectively connected to the single-chip microcomputer control module; the sources of MOS transistors Q1, Q2, Q3 and Q4 are respectively connected to the sources of MOS transistors Q2, Q3, Q4 and the amplification module.

[0007] For the above-mentioned wide-range and high-precision medical X-ray imaging system, the high-precision DC bias module includes a reference voltage chip U2, a resistor R1 and a capacitor C1; one end of the resistor R1 is connected to a 5V voltage source, and the other end of the resistor R1 is respectively connected to one end of the capacitor C1, the power supply pin of the reference voltage chip U2, the output pin of the reference voltage chip U2 and the amplification module; the other end of the capacitor C1 is connected to the ground pin of the reference voltage chip U2 and grounded.

[0008] The aforementioned wide-range and high-precision medical X-ray imaging system, the amplification module includes a rail-to-rail operational amplifier U1, an input interference suppression capacitor C2, a resistor R2, a resistor R3, a resistor R4, and a resistor R5; one end of the resistor R2 is connected to the high-precision DC bias module, and the other end of the resistor R2 is respectively connected to one end of the resistor R3, one end of the input interference suppression capacitor C2, and the non-inverting input terminal of the rail-to-rail operational amplifier U1; the other end of the resistor R3 is connected to the current-to-voltage module; the positive power supply terminal of the rail-to-rail operational amplifier U1 is connected to a 5V voltage source, and the negative power supply terminal of the rail-to-rail operational amplifier U1 is grounded; the output terminal of the rail-to-rail operational amplifier U1 is respectively connected to one end of the resistor R4 and the microcontroller control module; the inverting input terminal of the rail-to-rail operational amplifier U1 is respectively connected to the other end of the resistor R4 and one end of the resistor R5; the other end of the resistor R5 is respectively connected to the other end of the input interference suppression capacitor C2 and the current-to-voltage module, and is grounded.

[0009] The aforementioned wide-range and high-precision medical X-ray imaging system, the microcontroller control module includes a microcontroller MCU and a filtering circuit; the P1 port, P2 port, P3 port, and P4 port of the microcontroller MCU are respectively connected to the current-to-voltage module; the AD port of the microcontroller MCU is connected to one end of the filtering circuit; the other end of the filtering circuit is connected to the amplification module.

[0010] The aforementioned wide-range and high-precision medical X-ray imaging system, the rated operating current and body resistance R of the MOS transistor Q1 sh are 150A and 4mΩ respectively; the rated operating current and body resistance of the MOS transistor Q2 are 100A and 6mΩ respectively; the rated operating current and body resistance of the MOS transistor Q3 are 50A and 10mΩ respectively; the rated operating current and body resistance of the MOS transistor Q4 are 10A and 50mΩ respectively.

[0011] The aforementioned wide-range and high-precision medical X-ray imaging system, the model of the reference voltage chip U2 is TL431; the output pin of the reference voltage chip U2 outputs a high-precision DC bias voltage of 2.5V.

[0012] The aforementioned wide-range and high-precision medical X-ray imaging system, the resistance value of the resistor R2 is the same as that of the resistor R4; the resistance value of the resistor R3 is the same as that of the resistor R5; the resistance value of the resistor R3 is 1 / 4 of the resistance value of the resistor R2; the sampling voltage v0 at the output terminal of the rail-to-rail operational amplifier U1 satisfies the following formula:

[0013] v0 = 2.5 + 4v ac ;

[0014] where, v ac is the conversion voltage, vac = i ac × R sh ; i ac is the alternating current in the tube current circuit; R sh is the body resistance of the MOS transistor.

[0015] For the aforementioned wide-range and high-precision medical X-ray imaging system, a current detection program is set in the single-chip microcomputer MCU, and the current detection program includes the following steps:

[0016] S1: Start;

[0017] S2: Calculate the conversion voltage v ac , and obtain the amplitude V amp of the conversion voltage;

[0018] S3: Calculate i ac and I amp respectively according to the conversion voltage v ac and the amplitude V amp of the conversion voltage; where, i ac = K · v ac ; I amp = K · V amp ; K is the amplification factor, K = 1 / R sh ;

[0019] S4: Judge whether I amp < 10 holds; if so, go to step S5; otherwise, go to step S6;

[0020] S5: The single-chip microcomputer MCU control port outputs P1 = 0, P2 = 0, P3 = 0, P4 = 1, K = 20, and the program exits;

[0021] S6: Judge whether 10.5 ≤ I amp < 50 holds; if so, go to step S7; otherwise, go to step S8;

[0022] S7: The single-chip microcomputer MCU control port outputs P1 = 0, P2 = 0, P3 = 1, P4 = 0, K = 100, and the program exits;

[0023] S8: Judge whether 50.5 ≤ I amp < 100 holds; if so, go to step S9; otherwise, go to step S10;

[0024] S9: The single-chip microcomputer MCU control port outputs P1 = 0, P2 = 1, P3 = 0, P4 = 0, K = 166.67, and the program exits;

[0025] S10: Judge whether 100.5 ≤ I ampWhether <150> holds; if yes, go to step S11; otherwise, go to step S12;

[0026] S11: The microcontroller MCU control port outputs P1 = 1, P2 = 0, P3 = 0, P4 = 0, K = 250, and the program exits;

[0027] S12: Determine whether 150.5 ≤ I amp <200 holds; if yes, go to step S13; otherwise, go to step S14;

[0028] S13: The microcontroller MCU control port outputs P1 = 1, P2 = 0, P3 = 1, P4 = 0, K = 350, and the program exits;

[0029] S14: The microcontroller MCU control port outputs P1 = 1, P2 = 1, P3 = 0, P4 = 0, K = 416.7, and the program exits;

[0030] S15: The program exits.

[0031] Compared with the prior art, the present invention includes a power supply circuit for providing high - voltage power supply for the X - ray source; an X - ray source for generating X - rays; a tube current circuit for controlling the intensity and exposure time of the X - rays; a tube voltage circuit for controlling the acceleration energy of the X - ray source electrons and the energy of the X - rays; a current detection circuit for detecting the current of the X - ray source and providing a current feedback signal to the control circuit; a control circuit for receiving the current feedback signal of the current detection circuit and controlling the operation of the power supply circuit, the tube current circuit, and the tube voltage circuit; the tube current circuit is connected to a current - to - voltage conversion module, and the current - to - voltage conversion module converts alternating currents of different ranges into voltage signals of appropriate ranges; a high - precision DC bias module outputs a high - precision DC bias voltage; an amplification module realizes interference filtering, DC biasing, and amplification of the converted voltage signal; a microcontroller control module realizes high - precision measurement of current when the current changes in a wide range; the present invention can meet the requirements of wide - range and high - precision current detection in the X - ray imaging system, and has the advantages of low cost, wide current measurement range, and high precision. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a schematic structural diagram of the present invention;

[0033] Figure 2 is a circuit diagram of the current detection circuit;

[0034] Figure 3 is an algorithm flowchart of the current detection program of the microcontroller MCU.

[0035] The reference numerals in the drawings are: 1 - current - to - voltage conversion module, 2 - high - precision DC bias module, 3 - amplification module, 4 - microcontroller control module. Detailed implementation manners

[0036] The present invention will be further described below in conjunction with the accompanying drawings and embodiments, but it shall not be used as a basis for limiting the present invention.

[0037] Embodiment: A wide-range and high-precision medical X-ray imaging system has a structure as Figure 1 shown, and includes a power supply circuit, an X-ray source, a tube current circuit, a tube voltage circuit, a current detection circuit, and a control circuit; the power supply circuit is respectively connected to the X-ray source and the control circuit, and is used to provide a high-voltage power supply for the X-ray source, provide the required high voltage for the X-ray tube, accelerate the electrons in the X-ray tube and generate X-rays; the X-ray source is an X-ray tube, which includes a cathode filament and an anode target. A high-voltage current is applied to the cathode filament through the tube current circuit, so that the electrons in the cathode filament are accelerated to hit the anode target to generate X-rays; the tube current circuit is respectively connected to the X-ray source and the control circuit, and can form a closed-loop control by combining the feedback signal of the current detection circuit through the control circuit, which can ensure the stability and accuracy of the X-ray source current, and can control the intensity and exposure time of the X-rays; the tube voltage circuit is respectively connected to the X-ray source and the control circuit, and is used to control the acceleration energy of the X-ray source electrons and the energy of the X-rays; the current detection circuit is respectively connected to the tube current circuit and the control circuit, and is used to detect the current of the X-ray source and provide a current feedback signal to the control circuit; the control circuit is used to receive the current feedback signal of the current detection circuit and control the operation of the power supply circuit, the tube current circuit, and the tube voltage circuit;

[0038] The current detection circuit includes a current-to-voltage module 1, a high-precision DC bias module 2, an amplification module 3, and a single-chip microcomputer control module 4; the single-chip microcomputer control module 4 is respectively connected to the current-to-voltage module 1 and the amplification module 3; the amplification module 3 is respectively connected to the current-to-voltage module 1 and the high-precision DC bias module 2.

[0039] The present invention includes a power supply circuit for providing high-voltage power to an X-ray source; an X-ray source for generating X-rays; a tube current circuit for controlling the intensity and exposure time of the X-rays; a tube voltage circuit for controlling the acceleration energy of the electrons in the X-ray source and the energy of the X-rays; a current detection circuit for detecting the current of the X-ray source and providing a current feedback signal to a control circuit; a control circuit for receiving the current feedback signal of the current detection circuit and controlling the operation of the power supply circuit, the tube current circuit and the tube voltage circuit; the tube current circuit is connected to a current-to-voltage conversion module, and the current-to-voltage conversion module converts alternating current with different ranges into voltage signals with appropriate ranges; a high-precision DC bias module outputs a high-precision DC bias voltage; an amplification module filters out interference, applies DC bias and amplifies the converted voltage signal; a single-chip microcomputer control module realizes high-precision measurement of current when it changes within a wide range; the present invention can meet the requirements of wide-range and high-precision current detection in an X-ray imaging system, and has the advantages of low cost, wide current measurement range and high precision.

[0040] The current-to-voltage conversion module 1 includes MOS transistors Q1, Q2, Q3 and Q4; the current-to-voltage conversion module 1 is connected in parallel with the tube voltage circuit; the drain of the MOS transistor Q1 is respectively connected to the drains of the MOS transistors Q2, Q3, Q4 and the amplification module 3; the gates of the MOS transistors Q1, Q2, Q3 and Q4 are respectively connected to the single-chip microcomputer control module 4; the sources of the MOS transistors Q1, Q2, Q3 and Q4 are respectively connected to the sources of the MOS transistors Q2, Q3, Q4 and the amplification module 3. The rated operating current and body resistance R of the MOS transistor Q1 sh are 150 A and 4 mΩ respectively; the rated operating current and body resistance of the MOS transistor Q2 are 100 A and 6 mΩ respectively; the rated operating current and body resistance of the MOS transistor Q3 are 50 A and 10 mΩ respectively; the rated operating current and body resistance of the MOS transistor Q4 are 10 A and 50 mΩ respectively.

[0041] The current-to-voltage conversion module 1 uses different body resistances R after different MOS transistors are turned on sh to convert alternating current i with different ranges ac into voltage signals v with appropriate ranges ac . The MOS transistors Q1, Q2, Q3 and Q4 are respectively driven by the P1 port, P2 port, P3 port and P4 port of the single-chip microcomputer MCU, and wide-range i ac conversion v ac. MOS transistors Q1, Q2, Q3, and Q4 form four branches and are connected in parallel to the AC power line. The gates of MOS transistors Q1, Q2, Q3, and Q4 are sequentially connected to the output control ports P1 port, P2 port, P3 port, and P4 port of the single-chip microcomputer MCU and are controlled by the single-chip microcomputer MCU. The single-chip microcomputer MCU obtains the amplitude I ac of i amp through sampling and calculation, and controls the level switching of the P1 port, P2 port, P3 port, and P4 port according to the size of I amp , and then optimally selects the bulk resistance R sh of the current-to-voltage conversion. On the one hand, it ensures that the sampling voltage v0 is within the sampling linear range of the AD port of the single-chip microcomputer MCU, and on the other hand, it reduces the sampling quantization error of the AD port of the single-chip microcomputer MCU and the influence of interference on i ac , realizing the measurement of current with wide range and high precision.

[0042] Since there are parasitic diodes inside MOS transistors Q1, Q2, Q3, and Q4, to ensure the linearity of the i ac -to-v ac conversion and the measurement accuracy, it is necessary to ensure that the parasitic diodes are in the cut-off state. Due to the differences in the manufacturers, materials, and production processes of MOS transistors, the conduction voltages of the parasitic diodes inside the MOS transistors are different. To ensure the reliable cut-off of the MOS transistors, the amplitude V ac of v amp cannot exceed 0.6V. Therefore, when MOS transistor Q4 is selected to conduct, then i ac and v ac satisfy:

[0043] v ac = i ac × R sh = i ac × 0.05; (1)

[0044] So there is:

[0045] V amp = I amp × 0.05; (2)

[0046] Among them: V amp is the amplitude of v ac , and I amp is the amplitude of i ac . Also, because V amp < 0.6, so there is:

[0047] I amp < 12; (3)

[0048] As can be seen from (3), when selecting the MOS transistor Q4 to conduct, to reliably ensure that v ac = i ac ×0.05 has a linearity, the amplitude I ac of the current i amp shall not be greater than 12 A, that is, the range of i ac can be selected as 0 - 12 A.

[0049] Similarly, when selecting the MOS transistor Q3 to conduct, then i ac and v ac satisfy:

[0050] v ac = i ac ×0.01; (4)

[0051] Because V amp < 0.6, so there is:

[0052] I amp < 60; (5)

[0053] Therefore, the amplitude I ac of the current i amp shall not be greater than 60 A, that is, the range of i ac can be selected as 12 - 60 A.

[0054] By analogy, when selecting the MOS transistor Q2 to conduct, then i ac and v ac satisfy:

[0055] v ac = i ac ×0.006; (6)

[0056] Therefore, the amplitude I ac of the current i amp shall not be greater than 100 A, that is, the range of i ac can be selected as 60 - 100 A.

[0057] When selecting the MOS transistor Q1 to conduct, then i ac and v ac satisfy:

[0058] v ac = i ac ×0.004; (7)

[0059] Therefore, the amplitude I ac of the current i amp shall not be greater than 150 A, that is, the range of i ac can be selected as 100 - 150 A.

[0060] When MOS transistor Q1 and MOS transistor Q3 are selected to conduct, then i ac and v ac satisfy:

[0061] v ac = i ac ×0.00286; (8)

[0062] Therefore, the amplitude I ac of the current i amp is not greater than 210 A, that is, the range of i ac can be selected as 150 - 210 A.

[0063] When MOS transistor Q1 and MOS transistor Q2 are selected to conduct, then i ac and v ac satisfy:

[0064] v ac = i ac ×0.0024; (9)

[0065] Therefore, the amplitude I ac of the current i amp is not greater than 250 A, that is, the range of i ac can be selected as 210 - 250 A.

[0066] In order to make the current have the same range width and be convenient for calculation, the current range intervals of the present invention are respectively: 0 - 10 A, 10 - 50 A, 50 - 100 A, 100 - 150 A, 150 - 200 A, and 200 - 250 A.

[0067] As can be seen from the above analysis, by controlling the conduction combination modes of MOS transistor Q1, MOS transistor Q2, MOS transistor Q3, and MOS transistor Q4, the current i ac converted voltage v ac within a large range can have the same interval width and measurement accuracy.

[0068] The high-precision DC bias module 2 includes a reference voltage chip U2, a resistor R1 and a capacitor C1; one end of the resistor R1 is connected to a 5V voltage source, and the other end of the resistor R1 is respectively connected to one end of the capacitor C1, the power supply pin of the reference voltage chip U2, the output pin of the reference voltage chip U2 and the amplification module 3; the other end of the capacitor C1 is connected to the ground pin of the reference voltage chip U2 and is grounded. The model of the reference voltage chip U2 is TL431; the output pin of the reference voltage chip U2 outputs a high-precision DC bias voltage of 2.5V. The resistor R1 is used to regulate the input current of the power supply pin of the TL431 reference voltage chip U2. By reasonably selecting the resistance value of the resistor R1, it can be ensured that the TL431 reference voltage chip U2 outputs a high-precision DC bias voltage of 2.5V. The capacitor C1 is used to suppress the high-frequency ripple of the 2.5V voltage. The output pin of the TL431 reference voltage chip U2 outputs stably at 2.5V, which requires the power supply pin to be injected with a current between 1-100mA. Considering the fluctuation of the circuit working voltage 5V, the working range of the TL431 reference voltage chip U2 and the bias voltage V bias To generate the current required by the circuit, set the current injected into the power supply pin of the TL431 reference voltage chip U2 to 10mA, so:

[0069]

[0070] The amplification module 3 includes a rail-to-rail operational amplifier U1, an input interference suppression capacitor C2, a resistor R2, a resistor R3, a resistor R4 and a resistor R5, which can realize the input amplification module V acThe signal is subjected to interference filtering, DC biasing, and amplification; one end of the resistor R2 is connected to the high-precision DC biasing module 2, and the other end of the resistor R2 is respectively connected to one end of the resistor R3, one end of the input interference suppression capacitor C2, and the non-inverting input terminal of the rail-to-rail operational amplifier U1; the other end of the resistor R3 is connected to the current-to-voltage module 1; the positive power supply terminal of the rail-to-rail operational amplifier U1 is connected to a 5V voltage source, and the negative power supply terminal of the rail-to-rail operational amplifier U1 is grounded; the output terminal of the rail-to-rail operational amplifier U1 is respectively connected to one end of the resistor R4 and the microcontroller control module 4; the inverting input terminal of the rail-to-rail operational amplifier U1 is respectively connected to the other end of the resistor R4 and one end of the resistor R5; the other end of the resistor R5 is respectively connected to the other end of the input interference suppression capacitor C2 and the current-to-voltage module 1, and is grounded. The resistance value of the resistor R2 is 4R; the resistance value of the resistor R3 is R; the resistance value of the resistor R4 is 4R; the resistance value of the resistor R5 is R; the amplification factor of the amplification module 3 is 4 (that is, the resistance value of the resistor R2 is the same as the resistance value of the resistor R4; the resistance value of the resistor R3 is the same as the resistance value of the resistor R5; the resistance value of the resistor R3 is 1 / 4 of the resistance value of the resistor R2); the sampled voltage v0 at the output terminal of the rail-to-rail operational amplifier U1 satisfies the following formula:

[0071]

[0072]

[0073] v0 = 2.5 + 4v ac ; (13)

[0074] where, v ac is the conversion voltage, v ac = i ac ×R sh ; i ac is the AC current in the tube current circuit; v (+) is the voltage at the non-inverting input terminal of the rail-to-rail operational amplifier U1; v (-) is the voltage at the inverting input terminal of the rail-to-rail operational amplifier U1; R sh is the body resistance of the MOS transistor.

[0075] The microcontroller control module 4 includes a microcontroller MCU and a filter circuit; the P1 port, P2 port, P3 port, and P4 port of the microcontroller MCU are respectively connected to the current-to-voltage module 1; the AD port of the microcontroller MCU is connected to one end of the filter circuit; the other end of the filter circuit is connected to the amplification module 3. The filter circuit can achieve high-frequency interference filtering for v0; the microcontroller MCU calculates the amplitude of i ac through v0, and based on i acReasonably select the conduction of MOS transistors Q1, Q2, Q3, and Q4 according to the magnitude of the amplitude to achieve high-precision measurement of current when the current changes within a wide range.

[0076] A current detection program is set in the single-chip microcomputer MCU, and the current detection program is as Figure 3 shown, including the following steps:

[0077] S1: Start;

[0078] S2: Calculate the conversion voltage v ac according to the sampling voltage v0, and obtain the amplitude V amp of the conversion voltage;

[0079] S3: Calculate i ac and I amp respectively according to the conversion voltage v ac and the amplitude V amp of the conversion voltage; where, i ac = K·v ac ; I amp = K·V amp ; K is the amplification factor, K = 1 / R sh ;

[0080] S4: Judge whether I amp < 10 holds; if so, go to step S5; otherwise, go to step S6;

[0081] S5: The single-chip microcomputer MCU control port outputs P1 = 0, P2 = 0, P3 = 0, P4 = 1, K = 20, and the program exits;

[0082] S6: Judge whether 10.5 ≤ I amp < 50 holds; if so, go to step S7; otherwise, go to step S8;

[0083] S7: The single-chip microcomputer MCU control port outputs P1 = 0, P2 = 0, P3 = 1, P4 = 0, K = 100, and the program exits;

[0084] S8: Judge whether 50.5 ≤ I amp < 100 holds; if so, go to step S9; otherwise, go to step S10;

[0085] S9: The single-chip microcomputer MCU control port outputs P1 = 0, P2 = 1, P3 = 0, P4 = 0, K = 166.67, and the program exits;

[0086] S10: Judge whether 100.5 ≤ I amp < 150 holds; if so, go to step S11; otherwise, go to step S12;

[0087] S11: The single-chip microcomputer MCU control port outputs P1 = 1, P2 = 0, P3 = 0, P4 = 0, K = 250, and the program exits.

[0088] S12: Determine whether 150.5 ≤ I amp <200 holds; if so, proceed to step S13; otherwise, proceed to step S14.

[0089] S13: The single-chip microcomputer MCU control port outputs P1 = 1, P2 = 0, P3 = 1, P4 = 0, K = 350, and the program exits.

[0090] S14: The single-chip microcomputer MCU control port outputs P1 = 1, P2 = 1, P3 = 0, P4 = 0, K = 416.7, and the program exits.

[0091] S15: The program exits.

[0092] In summary, the present invention includes a power supply circuit for providing a high-voltage power supply for the X-ray source; an X-ray source for generating X-rays; a tube current circuit for controlling the intensity and exposure time of the X-rays; a tube voltage circuit for controlling the acceleration energy of the X-ray source electrons and the energy of the X-rays; a current detection circuit for detecting the current of the X-ray source and providing a current feedback signal to the control circuit; a control circuit for receiving the current feedback signal of the current detection circuit and controlling the operation of the power supply circuit, the tube current circuit, and the tube voltage circuit; the tube current circuit is connected to a current-to-voltage conversion module, and the current-to-voltage conversion module converts alternating currents of different ranges into voltage signals of appropriate ranges; a high-precision DC bias module outputs a high-precision DC bias voltage; an amplification module realizes interference filtering, DC biasing, and amplification of the converted voltage signal; a single-chip microcomputer control module realizes high-precision measurement of the current when the current changes in a wide range; the present invention can meet the requirements of wide-range and high-precision current detection in the X-ray imaging system, and has the advantages of low cost, wide current measurement range, and high precision.

Claims

1. A medical X-ray imaging system with a wide range and high precision, characterized in that: It includes a power supply circuit, an X-ray source, a tube current circuit, a tube voltage circuit, a current detection circuit and a control circuit; the power supply circuit is connected to the X-ray source and the control circuit respectively, and the power supply circuit is used to provide a high-voltage power supply for the X-ray source; the tube current circuit is connected to the X-ray source and the control circuit respectively, and the tube current circuit is used to control the intensity and exposure time of the X-rays; the tube voltage circuit is connected to the X-ray source and the control circuit respectively, and the tube voltage circuit is used to control the acceleration energy of the X-ray source electrons and the energy of the X-rays; The current detection circuit is connected to the tube current circuit and the control circuit respectively, and the current detection circuit is used to detect the current of the X-ray source and provide a current feedback signal to the control circuit; The control circuit is used to receive the current feedback signal of the current detection circuit and control the operation of the power supply circuit, the tube current circuit and the tube voltage circuit; The current detection circuit comprises a current-to-voltage module (1), a high-precision DC bias module (2), an amplification module (3) and a single-chip control module (4); the single-chip control module (4) is respectively connected to the current-to-voltage module (1) and the amplification module (3); the amplification module (3) is respectively connected to the current-to-voltage module (1) and the high-precision DC bias module (2); The current-to-voltage module (1) comprises a MOS tube Q1, a MOS tube Q2, a MOS tube Q3 and a MOS tube Q4; the current-to-voltage module (1) is connected in parallel with a tube voltage circuit; the drain of the MOS tube Q1 is respectively connected to the drain of the MOS tube Q2, the drain of the MOS tube Q3, the drain of the MOS tube Q4 and the amplification module (3); the gate of the MOS tube Q1, the gate of the MOS tube Q2, the gate of the MOS tube Q3 and the gate of the MOS tube Q4 are respectively connected to a single-chip control module (4); the source of the MOS tube Q1 is respectively connected to the source of the MOS tube Q2, the source of the MOS tube Q3, the source of the MOS tube Q4 and the amplification module (3); The rated operating current and body resistance R of the MOS tube Q1 sh The rated operating current and body resistance of the MOS tube Q2 are 100A and 6mΩ respectively; the rated operating current and body resistance of the MOS tube Q3 are 50A and 10mΩ respectively; the rated operating current and body resistance of the MOS tube Q4 are 10A and 50mΩ respectively.

2. The wide-range and high-precision medical X-ray imaging system according to claim 1, characterized in that: The high-precision DC bias module (2) comprises a reference voltage chip U2, a resistor R1 and a capacitor C1; one end of the resistor R1 is connected to a 5V voltage source, and the other end of the resistor R1 is respectively connected to one end of the capacitor C1, a power supply pin of the reference voltage chip U2, an output pin of the reference voltage chip U2 and an amplification module (3); the other end of the capacitor C1 is connected to a ground pin of the reference voltage chip U2 and is grounded.

3. The wide-range and high-precision medical X-ray imaging system according to claim 2, characterized in that: The amplification module (3) comprises a rail-to-rail operational amplifier U1, an input interference suppression capacitor C2, a resistor R2, a resistor R3, a resistor R4 and a resistor R5; one end of the resistor R2 is connected to the high-precision DC bias module (2), and the other end of the resistor R2 is respectively connected to one end of the resistor R3, one end of the input interference suppression capacitor C2 and the non-inverting input end of the rail-to-rail operational amplifier U1; the other end of the resistor R3 is connected to the current-to-voltage module (1); the positive power supply end of the rail-to-rail operational amplifier U1 is connected to a 5V voltage source, and the negative power supply end of the rail-to-rail operational amplifier U1 is grounded; the output end of the rail-to-rail operational amplifier U1 is respectively connected to one end of the resistor R4 and the single-chip control module (4); the inverting input end of the rail-to-rail operational amplifier U1 is respectively connected to the other end of the resistor R4 and one end of the resistor R5; the other end of the resistor R5 is respectively connected to the other end of the input interference suppression capacitor C2 and the current-to-voltage module (1), and is grounded.

4. The wide-range and high-precision medical X-ray imaging system according to claim 3, characterized in that: The single-chip microcomputer control module (4) comprises a single-chip microcomputer MCU and a filter circuit; the P1 port, the P2 port, the P3 port and the P4 port of the single-chip microcomputer MCU are respectively connected to the current-to-voltage module (1); the AD port of the single-chip microcomputer MCU is connected to one end of the filter circuit; and the other end of the filter circuit is connected to the amplification module (3).

5. The wide-range and high-precision medical X-ray imaging system according to claim 2, characterized in that: The model of the reference voltage chip U2 is TL431; the output pin of the reference voltage chip U2 outputs a high-precision DC bias voltage of 2.5V.

6. The wide-range and high-precision medical X-ray imaging system according to claim 3, characterized in that: The resistance value of the resistor R2 is the same as the resistance value of the resistor R4; the resistance value of the resistor R3 is the same as the resistance value of the resistor R5; the resistance value of the resistor R3 is 1 / 4 of the resistance value of the resistor R2; the sampling voltage v0 at the output end of the rail-to-rail operational amplifier U1 satisfies the following formula: v0=2.5+4v ac ; Among them, v ac is the conversion voltage, v ac =i ac ×R sh ;i ac is the AC current in the tube current circuit; R sh is the body resistance of the MOS tube.

7. The wide-range and high-precision medical X-ray imaging system according to claim 6, characterized in that: The single chip microcomputer MCU is provided with a current detection program, and the current detection program comprises the following steps: S1: Start; S2: Calculate the conversion voltage v according to the sampling voltage v0 ac , and obtain the amplitude of the conversion voltage V amp ; S3: According to the conversion voltage v ac and the amplitude of the conversion voltage V amp Calculate i separately ac and I amp ; where i ac =K·v ac ;I amp =K·V amp ; K is the amplification factor, K = 1 / R sh ; S4: Judgment I amp <10 is true; if so, go to step S5; otherwise, go to step S6; S5: MCU controls the port output P1=0, P2=0, P3=0, P4=1, K=20, and the program exits; S6: Determine 10.5≤I amp <50 is true; if so, go to step S7; otherwise, go to step S8; S7: MCU control port outputs P1=0, P2=0, P3=1, P4=0, K=100, and the program exits; S8: Determine 50.5≤I amp <100 is true; if so, go to step S9; otherwise, go to step S10; S9: MCU controls the port output P1=0, P2=1, P3=0, P4=0, K=166.67, and the program exits; S10: judge 100.5≤I amp <150 is true; if so, go to step S11; otherwise, go to step S12; S11: MCU controls the port output P1=1, P2=0, P3=0, P4=0, K=250, and the program exits; S12: Determine 150.5≤I amp <200 is true; if so, go to step S13; otherwise, go to step S14; S13: MCU controls the port output P1=1, P2=0, P3=1, P4=0, K=350, and the program exits; S14: MCU controls the port output P1=1, P2=1, P3=0, P4=0, K=416.7, and the program exits; S15: The program exits.

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