Circuit structure for generating electric field for treating tumors

Abstract

The invention discloses a circuit structure for generating an electric field for treating tumors. The circuit structure comprises a power supply circuit, a single chip microcomputer, an optocoupler driving circuit, a switching circuit and a sine wave generating circuit, the optocoupler driving circuit comprises two driving optocouplers; the switching circuit comprises two electronic switches and a transformer; the transformer comprises a primary coil with a center tap and a secondary coil; the single-chip microcomputer provides two paths of complementary PWM signals with dead zones to the two driving optocouplers. The two driving optocouplers are respectively used for driving the two power MOS tubes; the power supply circuit at least provides two paths of voltages with different voltage amplitudes, one path of voltage with low voltage amplitude serves as driving end voltage of the two driving optocouplers, the other path of voltage with high voltage amplitude is sent to a center tap of a primary coil of the transformer, and two ends of the primary coil and the ground form a loop through two electronic switches respectively. A secondary coil of the transformer is electrically connected with the sine wave generating circuit; the sine wave generating circuit generates high-frequency sine wave signals for treating a tumor electric field.

Description

Technical Field

[0001] This invention relates to the field of tumor electric field therapy technology, and more particularly to a circuit structure for generating electric fields for treating tumors. Background Technology

[0002] Tumor Treating Fields (TTFields / TTF) is an innovative tumor treatment technology, a novel portable tumor treatment device integrating mechanical, electronic, and software technologies. TTF delivers a low-intensity alternating electric field to the tumor site via electrodes, acting on the microtubules of cancer cells, interfering with tumor cell mitosis, inducing apoptosis in affected cancer cells, and inhibiting tumor growth. As a non-invasive anti-mitotic therapy, TTFields only targets mitotic cells and does not act on cells that are not actively dividing. Due to its local release mode and anti-mitotic effect, compared to traditional treatments such as surgery, radiotherapy, and drug therapy, TTFields therapy is more convenient, non-invasive, and has fewer side effects.

[0003] The tumor electric field therapy device mainly consists of components such as circuitry, electrodes, wires, and a casing. Patients are required to wear it for treatment as prescribed by their doctor. Due to individual differences in tumor size and shape among patients, it is necessary to provide an adjustable high-frequency sinusoidal wave therapy signal based on the specific situation. The traditional approach is as follows: Figure 1 As shown, the power supply circuit uses switching circuits 1 to 4 as an H-bridge, then generates positive and negative signals through transformer B, and finally generates a high-frequency sine wave signal through a sine wave generation circuit. However, this circuit increases the product size, makes the circuit more prone to overheating, and increases the production and usage costs. It also significantly increases the probability of damage during use.

[0004] The problems with traditional practices include:

[0005] 1) The H-bridge utilizes four electronic switching transistors. These transistors are also one of the main heat sources for the entire machine, with the energy coming from power supplies such as batteries. Therefore, more heat-generating components will result in shorter battery life for the same capacity. Increased heat generation leads to higher internal temperatures, requiring additional cooling equipment; otherwise, it will affect overall performance or cause damage.

[0006] 2) Driving four electronic switching transistors requires four driving circuits, and the upper transistor driving circuit of the H-bridge generally requires an additional, more complex power supply, which complicates the circuit.

[0007] 3) The H-bridge has a large number of 4-transistor components, which occupies a large area of ​​the circuit board, resulting in increased product cost and limited control over product size and production cost.

[0008] 4) The input signal of the drive circuit of the switching transistor is provided by the microcontroller. The program of 4-channel microcontroller signal is more complex and has higher requirements for the microcontroller function.

[0009] Therefore, those skilled in the art are dedicated to developing a circuit structure for generating electric fields to treat tumors, employing innovative hardware and software control schemes to overcome the aforementioned shortcomings, making the product more stable, lower in cost, and less heat generated. Summary of the Invention

[0010] In view of the above-mentioned deficiencies of the prior art, the technical problem to be solved by the present invention is how to reduce the number of switching transistors and their associated driving circuits, reduce the power loss of the circuit, and make the product more stable, less expensive, and generate less heat.

[0011] To achieve the above objectives, the present invention provides a circuit structure for generating therapeutic electric fields for tumors, comprising a power supply circuit, a microcontroller, an optocoupler driving circuit, a switching circuit, and a sine wave generation circuit; the optocoupler driving circuit includes two driving optocouplers; the switching circuit includes two electronic switches and a transformer, the transformer including a primary coil and a secondary coil with a center tap; the power supply circuit supplies power to the microcontroller, the optocoupler driving circuit, and the switching circuit; the microcontroller is configured to provide two PWM signals to the two driving optocouplers respectively, the two PWM signals being complementary PWM signals with dead time; the two driving optocouplers are respectively used to drive the two power MOSFETs; the power supply circuit provides at least two voltages with different amplitudes, wherein one voltage with a lower amplitude is used as the driving terminal voltage of the two driving optocouplers, and the other voltage with a higher amplitude is sent to the center tap of the primary coil of the transformer, the two ends of the primary coil respectively forming a loop with ground through the two electronic switches, and the secondary coil of the transformer is electrically connected to the sine wave generation circuit; the sine wave generation circuit is configured to generate a high-frequency sine wave signal for therapeutic tumor electric fields.

[0012] Furthermore, the two PWM signals are a first PWM signal and a second PWM signal, and the optocoupler driving circuit includes a first driving optocoupler and a second driving optocoupler. The first PWM signal is provided to the first driving optocoupler, and the second PWM signal is provided to the second driving optocoupler.

[0013] Furthermore, the first and second driving optocouplers use the TLP5772 chip, and the first PWM signal and the second PWM signal are electrically connected to the anodes of the first and second driving optocouplers, respectively.

[0014] Furthermore, it also includes a sinusoidal enable signal, which is electrically connected to the cathodes of the first and second driving optocouplers, and the sinusoidal enable signal is active low.

[0015] Furthermore, the power supply circuit includes a first voltage, which is electrically connected to the driving terminals of the first driving optocoupler and the second driving optocoupler, and the ground terminals of the first driving optocoupler and the second driving optocoupler are grounded.

[0016] Furthermore, the two electronic switches include one of two power MOSFETs, two power transistors, or two IGBTs.

[0017] Furthermore, the two electronic switches include a first power MOSFET and a second power MOSFET. The power supply circuit also includes a second voltage, the amplitude of which is higher than that of the first voltage. The second voltage is electrically connected to the center tap of the primary coil of the transformer. One end of the primary coil is electrically connected to the drain of the first power MOSFET, and the other end of the primary coil is electrically connected to the drain of the second power MOSFET. The sources of the first and second power MOSFETs are grounded. The output terminal of the first driving optocoupler is electrically connected to the gate of the first power MOSFET, and the output terminal of the second driving optocoupler is electrically connected to the gate of the second power MOSFET. Both the first and second power MOSFETs are N-channel power MOSFETs.

[0018] Furthermore, the power supply circuit includes a third voltage, which is provided to the microcontroller.

[0019] Furthermore, the voltage amplitude of the first voltage is 10-12V, and the voltage amplitude of the second voltage is adjustable.

[0020] Furthermore, the sine wave generating circuit is a low-pass filter.

[0021] Compared with the prior art, the present invention has the following main advantages:

[0022] (1) The number of switching transistors is reduced, the circuit is simplified, and high-frequency sine wave generation is achieved. The number of heat-generating components and power loss in the circuit are reduced, thereby extending battery life.

[0023] (2) While reducing the number of switching transistors, the number of drive circuits is also reduced. Furthermore, optocouplers with large output current are used to reduce the number of components on the circuit. The circuit is simple and can provide a qualified drive signal.

[0024] (3) Because the number of switching transistors is reduced, the total number of electronic components purchased is reduced, which can reduce the size of the circuit board or product, making it more convenient to carry and reducing production costs. With a reduction in the total number of components, the failure rate is also lower.

[0025] (4) While reducing the number of switching transistors, the number of input signal paths of the drive circuit is reduced, which also reduces the number of microcontroller output pins and functions, lowers the requirements for the microcontroller, and makes the program simpler, the software development time shorter, and the product launch cycle shorter.

[0026] The following will further explain the concept, specific structure, and technical effects of the present invention in conjunction with the accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Attached Figure Description

[0027] Figure 1 It is a circuit functional block diagram of the prior art;

[0028] Figure 2 This is a circuit diagram of a preferred embodiment of the switching circuit and the sine wave generating circuit of the present invention;

[0029] Figure 3 This is a circuit schematic diagram of an optocoupler driving circuit according to a preferred embodiment of the present invention;

[0030] Figure 4 This is a block diagram of the overall circuit function of a preferred embodiment of the present invention;

[0031] Figure 5 This is a schematic diagram of the overall circuit of a preferred embodiment of the present invention.

[0032] Among them, 1-power supply circuit, 2-microcontroller, 3-optocoupler drive circuit, 4-switching circuit, and 5-sine wave generation circuit. Detailed Implementation

[0033] The preferred embodiments of the present invention are described below with reference to the accompanying drawings to make the technical content clearer and easier to understand. The present invention can be embodied in many different forms, and the scope of protection of the present invention is not limited to the embodiments mentioned herein.

[0034] In the accompanying drawings, components with the same structure are indicated by the same numerical designation, and components with similar structures or functions are indicated by similar numerical designations. The dimensions and thicknesses of each component shown in the drawings are arbitrary, and the present invention does not limit the dimensions and thicknesses of each component. To make the illustrations clearer, the thickness of some components has been appropriately exaggerated in the drawings.

[0035] This invention reduces the number of electronic switches and their associated drive circuits by adding a center tap to the transformer, resulting in a more stable product, lower cost, and less heat generation.

[0036] This invention generates a sine wave using two electronic switches; it ensures the conduction level and switching speed of the electronic switches by driving the optocoupler output to a relatively high voltage VCC through a high current drive; it adjusts the amplitude of the sine wave output voltage by changing the output voltage of the electronic switches; and it uses a sine wave enable circuit to flexibly control the sine wave output to be turned off in the event of overcurrent during use.

[0037] Example

[0038] This embodiment provides a circuit structure for generating electric fields in tumor treatment. The overall circuit functional block diagram is shown below. Figure 4 The overall circuit schematic is shown below. Figure 5 The switching circuit and sine wave generation circuit sections are shown below. Figure 2 See the section on optocoupler drive circuit. Figure 3 The block diagram and circuit analysis are as follows:

[0039] like Figures 2 to 5 As shown, a circuit structure for generating electric fields for treating tumors consists of a power supply circuit 1, a microcontroller 2, an optocoupler drive circuit 3, a switch circuit 4, and a sine wave generation circuit 5. The power supply circuit 1 supplies power to the microcontroller 2, the optocoupler drive circuit 3, and the switch circuit 4. The microcontroller 2, the optocoupler drive circuit 3, the switch circuit 4, and the sine wave generation circuit 5 are connected in sequence.

[0040] This embodiment provides an innovative control scheme that combines hardware and software. The microcontroller 2 (STM32F407) generates a 3.3V high-frequency pulse width modulation (PWM) signal, which is output through two channels, PE9 and PB0. PE9 and PB0 are complementary PWM signals with dead time.

[0041] The PWM signal from PE9 of microcontroller 2 (STM32F407) passes through current-limiting resistor R77 to the anode A of the driving optocoupler U12 (TLP5772) in optocoupler driver circuit 3. The cathode C of the driving optocoupler U12 (TLP5772) in optocoupler driver circuit 3 is connected to the sine wave enable signal SPWMEN. The sine wave enable signal SPWMEN can be provided by microcontroller 2 or by another load current detection and processing circuit. Under normal operation, the sine wave enable signal SPWMEN is low. When the PWM of PE9 is high, the driving optocoupler U12 (TLP5772) in optocoupler driver circuit 3 is turned on. The power supply pin of the driving optocoupler U12 (TLP5772) in optocoupler driver circuit 3 is connected to the voltage VCC of power supply circuit 1. The output terminal V of the driving optocoupler U12 (TLP5772) in optocoupler driver circuit 3 is connected to the power supply pin. OThe output pulse voltage signal has the same pulse width as the PWM signal of PE9, but the voltage amplitude of this high-level pulse width signal is the voltage VCC of power supply circuit 1. This pulse voltage is higher than the PWM voltage amplitude of PE9 (3.3V). The voltage VCC of power supply circuit 1 is generally controlled between 10 and 12V. This pulse voltage then passes through resistor R81 and reaches the gate G of the power metal-oxide-semiconductor field-effect transistor (MOSFET) Q7 in switching circuit 4, causing the power MOSFET Q7 to conduct. The voltage VDD of power supply circuit 1 passes through the center tap 4 of the primary coil of transformer B1 (the center taps 4 and 5 are shorted together in the circuit). The primary coil of transformer B1, the drain D and source S of power MOSFET Q7, and the ground (GND) of power supply circuit 1 form a loop. A negative pulse voltage energy signal is generated in the secondary coil of transformer B1, which is proportional to the VDD voltage in power supply loop 1 and the turns ratio of the primary and secondary coils of transformer B1. This voltage energy signal passes through the inductor L17 and capacitors C80 and C81 in the low-pass filter of the sine wave generation circuit 5 to generate a high-frequency sine wave negative half-cycle signal.

[0042] The PWM signal from PB0 of another microcontroller 2 (STM32F407) passes through the current-limiting resistor R86 to the anode A of the driving optocoupler U13 (TLP5772) in the optocoupler driver circuit 3. The cathode C of the driving optocoupler U13 (TLP5772) in the optocoupler driver circuit 3 is connected to the sine wave enable signal SPWMEN. The sine wave enable signal SPWMEN can be provided by microcontroller 2 or by another load current detection and processing circuit. Under normal operation, the enable signal SPWMEN is low. At this time, when the PWM of PB0 is high, the driving optocoupler U13 (TLP5772) in the optocoupler driver circuit 3 is turned on. The power supply pin of the driving optocoupler U13 (TLP5772) in the optocoupler driver circuit 3 is connected to the voltage VCC of the external power supply circuit 1. The output terminal V of the driving optocoupler U13 (TLP5772) in the optocoupler driver circuit 3 is connected to the external power supply circuit 1. OThe output pulse width is a high-level pulse signal with the same pulse width as the PWM signal of PB0. However, the voltage amplitude of this high-level pulse signal is the voltage VCC of power supply circuit 1. This pulse voltage is higher than the PWM voltage amplitude of PB0 (3.3V). The VCC voltage of power supply circuit 1 is generally controlled between 10 and 12V. This pulse voltage then passes through resistor R80 and reaches the gate G of power MOSFET Q8 in switching circuit 4, causing power MOSFET Q8 to conduct. The VDD voltage of power supply circuit 1 passes through the center tap 5 of the primary winding of transformer B1 (the center taps 4 and 5 are shorted together in the circuit). The primary winding 7 of transformer B1, the drain D and source S of power MOSFET Q8, and the ground (GND) of power supply circuit 1 form a loop. A positive pulse voltage energy signal is generated in the secondary winding of transformer B1, which is proportional to the VDD voltage in power supply circuit 1 and the turns ratio of the primary and secondary windings of the transformer. This voltage energy signal passes through the inductor L17 and capacitors C80 and C81 in the low-pass filter of sine wave generation circuit 5 to generate a high-frequency sine wave positive half-cycle signal.

[0043] In this embodiment, the output terminal 150K-1 of the sine wave generation circuit 5 generates a high-frequency sine wave signal of 100kHz to 200kHz. The specific frequency is controlled by the microcontroller 2.

[0044] Capacitor C79 decouples the VCC voltage at the drive pin of the drive optocoupler U12 (TLP5772) in optocoupler drive circuit 3. Capacitor C82, resistor R78, and diode D25 absorb spike signals during the operation of power MOSFET Q7 in switching circuit 4. Diode D28 and resistor R85 form a cutoff acceleration circuit for power MOSFET Q7. Resistor R84 is the gate-source resistor (Rgs) of power MOSFET Q7 in switching circuit 4, providing a release for the gate-source voltage (Vgs) of power MOSFET Q7.

[0045] Capacitor C84 decouples the VCC voltage at the drive pin of the drive optocoupler U13 (TLP5772) in optocoupler drive circuit 3. Capacitor C83, resistor R79, and diode D26 absorb spike signals during the operation of power MOSFET Q8 in switching circuit 4. Diode D27 and resistor R82 form a cutoff acceleration circuit for power MOSFET Q8 during operation. Resistor R83 is the gate-source resistor (Rgs) of power MOSFET Q8 in switching circuit 4, providing a release for the gate-source voltage (Vgs) of power MOSFET Q8.

[0046] Capacitors C77 and C78 are used for VDD voltage decoupling in power supply circuit 1.

[0047] The driving optocoupler U12, power MOSFET Q7, diodes D25 and D28, capacitors C79 and C82, and resistors R77, R78, R81, R85, and R84 form a circuit for generating the negative half-cycle of a sine wave.

[0048] The driver optocoupler U13, power MOSFET Q8, diodes D26 and D27, capacitors C83 and C84, and resistors R86, R80, R82, R83, and R79 form the circuit for generating the positive half-cycle of a sine wave. The circuits for the positive and negative half-cycles of the sine wave are the same, and the components are identical.

[0049] The power supply circuit 1 provides appropriate voltage and current to power each stage of the circuit, including 3.3V for the microcontroller 2 (STM32F407), 10-12V VCC voltage for the drive terminal of the optocoupler driver 3, and adjustable VDD voltage to power the switching circuit 4.

[0050] In this embodiment, the microcontroller 2 is not limited to STM32F407.

[0051] In this embodiment, power MOSFETs Q7 and Q8 can be replaced with power transistors, insulated-gate bipolar transistors (IGBTs), and other semiconductor power devices.

[0052] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A circuit structure for generating an electric field for treating tumors, characterized in that, The system includes a power supply circuit, a microcontroller, an optocoupler driving circuit, a switching circuit, and a sine wave generation circuit. The optocoupler driving circuit includes two driving optocouplers. The switching circuit includes two electronic switches and a transformer, which includes a primary coil and a secondary coil with a center tap. The power supply circuit supplies power to the microcontroller, the optocoupler driving circuit, and the switching circuit. The microcontroller is configured to provide two PWM signals to the two driving optocouplers, which are complementary PWM signals with dead time. The two driving optocouplers are used to drive two power MOSFETs. The power supply circuit provides at least two voltages with different amplitudes, one with a lower amplitude serving as the driving terminal voltage for the two driving optocouplers, and the other with a higher amplitude being sent to the center tap of the primary coil of the transformer. The two ends of the primary coil are connected to ground through the two electronic switches to form a loop. The secondary coil of the transformer is electrically connected to the sine wave generation circuit. The sine wave generation circuit is configured to generate a high-frequency sine wave signal for use in tumor treatment electric fields.

2. The circuit structure for generating an electric field for treating tumors as described in claim 1, characterized in that, The two PWM signals are a first PWM signal and a second PWM signal. The optocoupler driving circuit includes a first driving optocoupler and a second driving optocoupler. The first PWM signal is provided to the first driving optocoupler, and the second PWM signal is provided to the second driving optocoupler.

3. The circuit structure for generating an electric field for treating tumors as described in claim 2, characterized in that, The first and second drive optocouplers use TLP5772 chips, and the first PWM signal and the second PWM signal are electrically connected to the anodes of the first and second drive optocouplers, respectively.

4. The circuit structure for generating an electric field for treating tumors as described in claim 3, characterized in that, It also includes a sinusoidal enable signal, which is electrically connected to the cathodes of the first driving optocoupler and the second driving optocoupler, and the sinusoidal enable signal is active low.

5. The circuit structure for generating an electric field for treating tumors as described in claim 4, characterized in that, The power supply circuit includes a first voltage, which is electrically connected to the driving terminals of the first driving optocoupler and the second driving optocoupler, and the ground terminals of the first driving optocoupler and the second driving optocoupler are grounded.

6. The circuit structure for generating an electric field for treating tumors as described in claim 5, characterized in that, The two electronic switches include one of two power MOSFETs, two power transistors, or two IGBTs.

7. The circuit structure for generating an electric field for treating tumors as described in claim 6, characterized in that, The two electronic switches include a first power MOSFET and a second power MOSFET. The power supply circuit also includes a second voltage, the amplitude of which is higher than that of the first voltage. The second voltage is electrically connected to the center tap of the primary coil of the transformer. One end of the primary coil is electrically connected to the drain of the first power MOSFET, and the other end of the primary coil is electrically connected to the drain of the second power MOSFET. The sources of the first and second power MOSFETs are grounded. The output terminal of the first drive optocoupler is electrically connected to the gate of the first power MOSFET, and the output terminal of the second drive optocoupler is electrically connected to the gate of the second power MOSFET. Both the first and second power MOSFETs are N-channel power MOSFETs.

8. The circuit structure for generating an electric field for treating tumors as described in claim 1, characterized in that, The power supply circuit includes a third voltage, which is provided to the microcontroller.

9. The circuit structure for generating an electric field for treating tumors as described in claim 6, characterized in that, The voltage amplitude of the first voltage is 10-12V, and the voltage amplitude of the second voltage is adjustable.

10. The circuit structure for generating an electric field for treating tumors as described in claim 1, characterized in that, The sine wave generating circuit is a low-pass filter.

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