Ultrasonic pulse generator, echo protection circuit, imaging system and control method

Abstract

The present invention provides an ultrasonic pulse generator, echo protection circuit, imaging system, and control method. The high-frequency pulse generator designed in this invention features adjustable pulse width and pulse edge of the excitation pulse, thereby regulating the energy frequency distribution of the high-voltage excitation signal to better drive the transducer to produce a more powerful ultrasonic signal, resulting in an echo signal with a higher peak value and wider bandwidth. The high-frequency pulse generator designed in this invention can produce extremely narrow high-voltage pulse signals with fast rising and falling edges, thereby effectively exciting ultrahigh-frequency transducers (greater than 100 MHz). The T / R switch and control method designed in this invention achieves lower insertion loss and shortens the near-field dead zone, which has practical value in improving the signal-to-noise ratio of high-frequency ultrasonic imaging. This invention provides a new excitation and protection circuit approach for high-frequency ultrasonic imaging circuit systems, with excellent economic value and practicality.

Description

Technical Field

[0001] The present invention relates to the technical field of ultrasonic transducer pulse excitation systems, and in particular to an ultrasonic pulse generator, an echo protection circuit, an imaging system and a control method. Background Art

[0002] As a non-invasive, real-time diagnostic tool, ultrasound imaging technology has been widely used in various fields, including medical imaging and industrial inspection. With the increasing demand for finer image detail and higher diagnostic accuracy, the resolution of ultrasound imaging urgently needs to be further improved. One direct approach to improving ultrasound image resolution is to use higher ultrasound frequencies. Ultrahigh-frequency ultrasound imaging technology, currently exceeding 50 MHz, has seen increasing application in medical and industrial inspection in recent years due to its superior resolution and real-time imaging capabilities. In medicine, ultrahigh-frequency ultrasound is primarily used for imaging superficial areas, typically including the skin, eyes, and blood vessels. For example, intravascular ultrasound (IVUS) instruments typically use frequencies of 40-80 MHz, providing a resolution of approximately 100 microns. In industrial inspection, ultrasound microscopes (UM), a key inspection tool for microelectronic devices and key materials, typically utilize ultrasound frequencies above 100 MHz, capable of imaging with micron or even nanometer resolution.

[0003] As ultrasonic frequencies increase, the design of ultrasonic hardware systems faces higher technical requirements. In high-frequency and ultra-high-frequency ultrasonic imaging systems, the performance of the pulse generator, as the ultrasonic excitation source, is crucial. In order to drive the ultrasonic transducer to generate high-frequency ultrasonic signals, the pulse generator must have characteristics such as high voltage (usually greater than 60VPP), high-frequency bandwidth pulse output, and fast response. However, achieving high voltage and wide bandwidth in the pulse output requires extremely short pulse duration and extremely fast rise and fall times, which requires the pulse generator to have a very high conversion rate (dv / dt) and strong capacitive load driving capability.

[0004] Currently, there are two main types of ultra-high frequency, high-voltage pulse excitation waveforms: unipolar pulse output (0 to +V or –V to 0) and bipolar pulse output (±V). Unipolar pulses have a single voltage polarity, a shorter pulse width, a relatively simple circuit structure, and easy switching. Bipolar pulses, on the other hand, can achieve higher peak-to-peak voltages and eliminate DC components from the same power supply, but this increases circuit complexity and driving difficulty. Theoretically, bipolar drive offers higher energy efficiency for the same peak-to-peak voltage because the positive and negative biases cancel each other during transmission, preventing net DC accumulation on the transducer and heating. Unipolar pulses, on the other hand, have a broadband spectrum but are rich in low-frequency components. Furthermore, due to their energy dispersion, acoustic energy output is lower than with bipolar pulse excitation, resulting in lower echo amplitude. However, bipolar excitation concentrates energy near the center frequency, achieving higher electro-acoustic energy transfer efficiency and yielding a higher signal-to-noise ratio of the original echo signal. Since ultrahigh frequency ultrasound tissue attenuation is more serious and the imaging depth is shallow, it becomes more important and meaningful to use bipolar excitation pulses to excite the ultrahigh frequency transducer to obtain higher sensitivity and signal-to-noise ratio (deeper depth).

[0005] In recent years, many scholars and engineers have conducted research and exploration into high-frequency ultrasonic excitation sources. In 2007, K. Kirk Shung's team reported a bipolar pulse generator capable of generating bipolar pulses with a center frequency of 60 MHz and an amplitude of 160 Vpp. In 2012, Qiu Weibao's team proposed a reconfigurable single- and bipolar pulse generator capable of generating bipolar pulses with a center frequency of 35 MHz and 150 Vpp, as well as unipolar spike pulses with a width of 11 ns, a -6 dB bandwidth of 70 MHz, and 165 Vpp. In 2019, Yuri Onikienko's team developed a pulse generator based on a half-bridge GaN FET, achieving high-frequency excitation with unipolar pulses of 40 ns width and 80 Vpp. In 2024, Qiu Weibao's team designed an ultra-high-frequency pulse excitation system based on a multi-stage RF power amplifier chip, achieving bipolar pulse excitation with a center frequency of 120 MHz and an amplitude of 52.8 Vpp. However, using the Class B amplifier mode faces challenges such as low energy efficiency, high power consumption, high cost, and large size of high-frequency, high-voltage RF amplifier chips. Furthermore, the output excitation pulse amplitude is limited by the low amplitude of the RF amplifier, making it difficult to achieve a higher peak-to-peak voltage (Vpp). Patent CN112003591B discloses a Marx pulse generator circuit based on BJT avalanche conduction for ultra-high frequency transducer excitation. This circuit provides a method for achieving unipolar ultra-high frequency pulse excitation. The high-voltage pulse circuit utilizes a five-stage Marx structure, resulting in a relatively complex circuit structure and a unipolar spike pulse output waveform. Patent CN103633964A discloses a highly reliable, high-power, narrow pulse generator circuit, also producing unipolar pulses. Existing published reports have yet to identify a complete bipolar pulse generator circuit with a voltage amplitude greater than 100 Vpp, a maximum center frequency greater than 100 MHz, and adjustable frequency. Therefore, there is a real need and significance for developing a simple, high-peak-to-peak, high-frequency, and adjustable bipolar ultra-high frequency excitation generator.

[0006] On the other hand, in ultrasound imaging systems, since the transmitting and receiving circuits share a transducer, the high-voltage transmitting circuit is directly connected to the highly sensitive low-voltage receiving circuit. To prevent high-voltage pulses from damaging the low-voltage receiving circuit, an isolation protection circuit must be installed at the front end of the receiving path. This isolation protection circuit, also known as a T / R switch, must meet two requirements:

[0007] (1) Large-amplitude power pulse signals cannot pass through.

[0008] (2) Small amplitude ultrasonic echo signals allow passage with minimal attenuation.

[0009] Currently, the common T / R switch implementation methods mainly include: (1) bridge diode switching method, which uses diode conduction / cutoff to achieve isolation and does not require special control. (2) MOSFET / CMOS switching method. This type of design is often used in low-voltage or integrated ultrasound systems, with fast response speed and simple control. Both of the above methods face the problem of large attenuation of high-frequency ultrasound echoes, and the absolute signal amplitude of high-frequency echo signals is even lower. The large attenuation T / R switch will further reduce the echo signal-to-noise ratio, thereby reducing the ultrasound image quality and imaging depth. (3) The third method is to use a mechanical relay, which can achieve lower insertion loss and less echo attenuation, but has a slow response speed of up to ms, which is difficult to meet the requirements of high ultrasound pulse repetition frequency.

[0010] Therefore, for the T / R switch module in the high-frequency ultrasonic echo circuit, it is necessary to design a T / R switch implementation with low attenuation and fast response speed. Summary of the Invention

[0011] In order to achieve the above-mentioned purpose and other advantages of the present invention, the first purpose of the present invention is to provide an ultrasonic pulse generator, comprising two unipolar high-frequency and high-voltage pulse circuits and a Balun transformer; wherein,

[0012] The unipolar high-frequency and high-voltage pulse circuit includes a programmable delay circuit, a narrowed driving pulse circuit, and a high-frequency and high-voltage pulse generating circuit;

[0013] The programmable delay circuit is used to delay the input pulse;

[0014] The narrowed driving pulse circuit is used to generate a trigger signal with a minimum pulse width of 1 ns and an adjustable pulse width, thereby controlling the high-frequency and high-voltage pulse generating circuit to output a high-voltage narrow pulse;

[0015] The Balun transformer is used to couple and output high-voltage narrow pulses output by two unipolar high-frequency high-voltage pulse circuits.

[0016] Furthermore, the unipolar high-frequency high-voltage pulse circuit further includes a limiting circuit, which is used to effectively output a high-voltage pulse signal and prevent the echo signal from entering the transmitting circuit.

[0017] Furthermore, the limiting circuit is arranged between the high-frequency and high-voltage pulse generating circuit and the primary side of the Balun transformer.

[0018] Furthermore, the limiting circuit is arranged between the secondary side of the Balun transformer and the echo protection circuit.

[0019] Furthermore, the narrowed drive pulse circuit includes a NOT gate, a programmable delay chip, a first AND gate, a second AND gate and an RC circuit. The wide pulse signal is input through the NOT gate, the output end of the NOT gate is connected to the first input end of the first AND gate, the programmable delay chip connects the input end of the NOT gate to the second input end of the first AND gate, the output end of the first AND gate is connected to the first input end of the second AND gate, the output end of the first AND gate is connected to the second input end of the second AND gate via the RC circuit, and the output end of the second AND gate is connected to the high-frequency and high-voltage pulse generating circuit.

[0020] Furthermore, the high-frequency, high-voltage pulse generating circuit includes a gate driver, a gate driving resistor, a GaN-based transistor, a first resistor, and a capacitor. The gate driver is connected to the base of the transistor via the gate driving resistor, the emitter of the transistor is grounded, and the collector of the transistor is connected to the power supply via the first resistor and to the limiting circuit via the capacitor.

[0021] Furthermore, the limiting circuit is implemented by using series diodes.

[0022] Furthermore, the delay times of the programmable delay circuits in the two unipolar high-frequency and high-voltage pulse circuits are not equal, and the delay time difference is determined by the pulse width of the output pulse of the narrowed drive pulse circuit and is not less than the pulse width of the output pulse of the narrowed drive pulse circuit.

[0023] Furthermore, the output pulse width of the narrowed driving pulse circuit is controlled by an internal programmable delay chip.

[0024] Furthermore, the Balun transformer has a center tap on the primary side, two ports on the primary side are respectively connected to high-voltage narrow pulse outputs, the center tap is grounded, and the turns ratio between the primary side and the secondary side is 2:1, and the effective frequency coverage range is 5-300MHz.

[0025] Furthermore, the rated operating voltage of the transistor is greater than twice the voltage of the high-voltage power supply to prevent damage to the transistor caused by a reverse surge voltage.

[0026] A second object of the present invention is to provide an echo protection circuit for preventing the high-voltage pulses output by the ultrasonic pulse generator from damaging the low-voltage receiving circuit. The circuit utilizes a high-voltage analog multiplexing switch to implement a T / R switch function. The high-voltage analog multiplexing switch includes a shift register, a buffer, a level conversion module, and a high-voltage switch.

[0027] The switch control data is input into the shift register and the corresponding buffer, waiting for the switch trigger signal to change. After the signal changes, the high-voltage switch starts to operate to realize the state change.

[0028] Furthermore, the high-voltage switch is in an off state by default.

[0029] The third object of the present invention is to provide an ultrasonic imaging system, comprising the above-mentioned ultrasonic pulse generator and the above-mentioned echo protection circuit, wherein the echo protection circuit is used to prevent the high-voltage pulses output by the ultrasonic pulse generator from damaging the low-voltage receiving circuit.

[0030] A fourth object of the present invention is to provide a control method for an ultrasonic imaging system, based on the above-mentioned ultrasonic imaging system, comprising the following steps:

[0031] Before the pulse is emitted, the register data that requires the high-voltage switch action is pre-stored;

[0032] The controllable delay of pulse emission is achieved through a programmable delay circuit, and the pulse emission output is achieved in the middle of the conversion process of the high-voltage switch.

[0033] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0034] The high-frequency pulse generator designed in the present invention has the ability to adjust the pulse width and pulse edge of the excitation pulse, thereby regulating the energy frequency band distribution of the high-voltage excitation signal to better drive the transducer to generate a stronger energy ultrasonic signal and obtain an echo signal with a higher peak value and a wider bandwidth.

[0035] The high-frequency pulse generator designed in the present invention can realize extremely narrow high-voltage pulse signals with fast rising and falling edges, thereby achieving effective excitation of ultra-high frequency transducers (greater than 100 MHz).

[0036] The T / R switch and control method designed in this invention can achieve lower insertion loss and shorten the near-field dead zone time, which has practical value in improving the signal-to-noise ratio of high-frequency ultrasonic imaging. It also provides a new excitation and protection circuit method for high-frequency ultrasonic imaging circuit systems, with good economic value and practicality.

[0037] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and to implement it according to the contents of the description, the following preferred embodiments of the present invention are described in detail with reference to the accompanying drawings. The specific implementation methods of the present invention are given in detail by the following embodiments and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0039] Figure 1 Principle of high-frequency ultrasound imaging system Figure 1 ;

[0040] Figure 2 Principle of high-frequency ultrasound imaging system Figure 2 ;

[0041] Figure 3 This is the principle diagram of the high-frequency ultrasonic pulse excitation generator;

[0042] Figure 4 This is a circuit diagram for narrowing the driving pulse;

[0043] Figure 5 Generate signal waveforms and timing diagrams of each node in the 1ns signal process for the narrow drive pulse circuit;

[0044] Figure 6 Generate circuit diagrams for high-frequency, high-voltage pulses;

[0045] Figure 7 This is a diagram of the internal working process of the high voltage analog multiplexer switch;

[0046] Figure 8 A flow chart of a control method for a high-frequency ultrasonic imaging system;

[0047] Figure 9 This is a control timing diagram for a high-frequency ultrasonic imaging system;

[0048] Figure 10 It is a high voltage bipolar pulse waveform diagram;

[0049] Figure 11 This is a comparison chart of T / R switch insertion loss;

[0050] Figure 12 A schematic diagram of a computer device;

[0051] Figure 13 A schematic diagram of a computer-readable storage medium. DETAILED DESCRIPTION

[0052] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. It should be noted that, without conflict, the embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0053] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of the present invention.

[0054] The figure numbers in this application are only used to distinguish the various steps in the scheme and are not used to limit the execution order of the various steps. The specific execution order is subject to the description in the specification.

[0055] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in this specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0056] The main structure of the bipolar pulse generator designed by the present invention, which can realize ultra-high frequency (more than 100MHz center frequency) and high voltage (more than 100Vpp), is realized by two-way unipolar ultra-high frequency pulse interleaving control + Balun transformer coupling. Figure 1 、 Figure 2 As shown, the circuitry and control system for two unipolar pulses are included. The advantage of this topology is that both the positive and negative output pulses are generated by the same circuitry. By using only low-side drivers, the driver circuitry eliminates the virtual ground issues associated with high-side drivers, thus eliminating the delay introduced by the digital isolator circuitry. Furthermore, Balun transformer coupling provides current output isolation and enables bipolar pulse generation using a single high-voltage power supply. Unipolar (positive and negative) pulses can also be generated.

[0057] Among them, the unipolar high-frequency high-voltage pulse circuit gives priority to negative polarity pulse output, because under the same process conditions, N-channel field effect transistors have faster switching speeds and achieve faster dv / dt, which is more conducive to the generation of pulses with narrower pulse widths. In addition, the low-side drive control circuit is selected, which has low circuit complexity and is more convenient to drive. Figure 3 As shown in the figure, N-channel enhancement-mode field-effect transistors include common Si-based MOSFETs, GaN FETs, and SiC FETs. For ultra-high-frequency pulse excitation circuits, GaN FETs are preferred as the switching core due to their extremely high electron mobility, which enables faster switching speeds and lower on-resistance. Example 1

[0058] A high-frequency ultrasonic pulse excitation generator is used to excite an ultra-high frequency transducer, such as Figure 1-Figure 3 As shown, it includes two unipolar high-frequency high-voltage pulse circuits and a Balun transformer; wherein,

[0059] The unipolar high-frequency and high-voltage pulse circuit includes a programmable delay circuit, a narrowed driving pulse circuit, and a high-frequency and high-voltage pulse generating circuit;

[0060] The programmable delay circuit is used to delay the input pulse;

[0061] The narrowed driving pulse circuit is used to generate a trigger signal with a minimum pulse width of 1 ns and an adjustable pulse width, thereby controlling the high-frequency and high-voltage pulse generating circuit to output a high-voltage narrow pulse;

[0062] The Balun transformer is used to couple and output high-voltage narrow pulses output by two unipolar high-frequency high-voltage pulse circuits.

[0063] In some embodiments, a limiting circuit is further included, which is used to effectively output a high-voltage pulse signal and prevent the echo signal from entering the transmitting circuit. The topology of these circuits realizes the function of an ultra-high frequency unipolar pulse generator.

[0064] Furthermore, if Figure 1 As shown, the limiting circuit is arranged between the high-frequency and high-voltage pulse generating circuit and the primary side of the Balun transformer.

[0065] Furthermore, if Figure 2 As shown, the limiting circuit is arranged between the secondary side of the Balun transformer and the echo protection circuit (T / R switch).

[0066] In order to achieve ns-level pulse width high voltage pulse, it is necessary to first generate a trigger signal with a minimum pulse width of 1ns and an adjustable pulse width. The existing equipment that outputs 1ns short trigger adjustable signal is expensive, so this embodiment designs a low-cost extremely narrow trigger signal circuit, such as Figure 4 This circuit uses an easily generated wide pulse signal (e.g., 100ns) as input to generate a trigger pulse A with an adjustable minimum pulse width of 1ns. This in turn controls the subsequent gate driver circuit to output a 1ns drive pulse B, achieving fast switching of Q1.

[0067] Furthermore, if Figure 4 As shown, the narrowed drive pulse circuit includes a NOT gate G1 (SN74LVC1G14), a programmable delay chip IC1 (DS1124), a first AND gate G2 (SN74LVC1G08), a second AND gate G3 (SN74LVC1G08) and an RC circuit (2200Ω / 20pF). The wide pulse signal is input through the NOT gate, and the output end of the NOT gate is connected to the first input end of the first AND gate. The programmable delay chip is connected to the input end of the NOT gate and the second input end of the first AND gate, the output end of the first AND gate is connected to the first input end of the second AND gate, the output end of the first AND gate is connected to the second input end of the second AND gate via the RC circuit, and the output end of the second AND gate is connected to the high-frequency and high-voltage pulse generating circuit.

[0068] The delay time of the programmable delay chip IC1 can be adjusted by software in steps of 0.25ns, which facilitates precise adjustment of the width of the trigger pulse. Figure 5 The signal waveforms and timing of each node in the process of narrowing the drive pulse circuit to generate a 1ns signal are demonstrated.

[0069] Furthermore, if Figure 6As shown, the high-frequency, high-voltage pulse generating circuit includes a gate driver, gate driving resistors (R3 and R4), a GaN-based transistor Q1, a first resistor R2, and a capacitor C1. The gate driver is connected to the base of the transistor via the gate driving resistor, the emitter of the transistor is grounded, and the collector of the transistor is connected to the power supply HVP via the first resistor and to the limiting circuit via the capacitor.

[0070] High frequency and high voltage pulse generating circuit such as Figure 6 As shown, the gate driver circuit acts as a buffer between the low-voltage control signal and the high-voltage circuit. Appropriate design and device selection can maximize GaN FET switching speed. Unlike traditional silicon MOSFETs, eGaN FETs lack a parasitic body diode, but they conduct when operating in reverse and have a large reverse voltage drop (approximately -2.5V). Therefore, the gate driver must operate stably at a relatively negative switching node voltage (typically -5V). Furthermore, GaN FETs have stricter gate voltage tolerance than MOSFETs, which can easily lead to irreversible breakdown. Therefore, the gate driver must strictly control the maximum voltage of the drive signal to avoid overshoot. Furthermore, the fast switching characteristics of GaN FETs require the gate driver to have high dv / dt tolerance and extremely narrow pulse width output. High dv / dt tends to cause greater overshoot, so low-inductance design and layout are required for both the chip and the circuit.

[0071] To meet these requirements, the LMG1020 ultra-fast gate driver was selected in this embodiment. It offers a minimum pulse width of 1 ns, with typical rising and falling edges of 375 ps and 350 ps, ​​respectively, resulting in extremely high switching speeds. Its compact package (0.8 × 1.2 mm WCSP) effectively reduces parasitic inductance, ensuring low ringing performance and high current drive capability even under high-frequency operation.

[0072] Gate drive resistors R3 and R4 are primarily used to adjust the on- and off-state strength of the GaN FET, limiting the peak source current (I1) and sink current (I2) in the gate drive path, thereby reducing noise and ringing. However, the drive resistor values ​​need to be precisely selected to meet the requirements of this design. In this embodiment, to achieve the fastest switching speed, R3 and R4 can be set to 0 ohms to maximize the GaN switching speed. At the same time, the PCB needs to shorten the length of the gate drive chip and the GaN FET gate lead to minimize parasitic inductance and reduce overshoot.

[0073] High voltage narrow pulse output is achieved by using the fast turn-on and turn-off of Q1. Since the GaN-based transistor Q1 has a lower total gate charge ( ), higher switching speed and lower on-resistance ( ), which is more conducive to high-voltage, ultra-narrow pulse output applications. This design uses enhancement-mode gallium nitride transistors (EPC2019, Efficient Power Conversion Corporation, USA) as switching devices, which outperform traditional MOSFETs in many aspects.

[0074] The selection of resistor R2 is crucial in ultra-high-frequency pulse generation. On the one hand, a smaller R2 helps maximize the charging current and accelerate the rising edge speed. On the other hand, the maximum current limit when Q1 is on requires R2 to be greater than the value calculated by formula (1). Furthermore, R2's resistance and power dissipation must be optimized to balance circuit stability and pulse output performance.

[0075] Formula (1);

[0076] Among them, V_HP is the high voltage power supply voltage, I_max is the maximum pulse current allowed to pass through Q1, is the on-resistance of Q1.

[0077] In this design, a 2.5 ohm high-power pulse resistor is selected as its resistance value. Its pulse instantaneous power consumption and average power consumption need to be calculated to select the appropriate resistor.

[0078] The limiting circuit is a device that can effectively output high-voltage pulse signals and prevent echo signals from entering the transmitting circuit. Figure 6 As shown, the series diode D1 is selected to realize the function of the limiting circuit. In this design, the BAV99 chip is used as the limiting circuit core, and the load resistance is 50 ohms.

[0079] Furthermore, the delay times of the programmable delay circuits in the two unipolar high-frequency and high-voltage pulse circuits are not equal, and the delay time difference is determined by the pulse width of the output pulse of the narrowed drive pulse circuit and is not less than the pulse width of the output pulse of the narrowed drive pulse circuit.

[0080] Furthermore, the output pulse width of the narrowed driving pulse circuit is controlled by an internal programmable delay chip.

[0081] The generation process of the bipolar pulse generator is as follows: by controlling the programmable delay circuit 1 and the programmable delay circuit 2, the input pulse obtains delay time 1 and delay time 2, wherein delay time 1 is less than delay time 2, and the time difference between delay time 2 and delay time 1 is determined by the pulse width of the output pulse of the narrowing drive circuit, and needs to be greater than or equal to the pulse width of the output pulse of the narrowing circuit. Figure 4As shown, the circuit consists of a delay chip, an AND logic gate, and an RC circuit. The narrowed output pulse width is controlled by the internal delay chip. Preferably, the delay chip parameters in the narrowed drive pulse circuit are set to be consistent, and the RC component values ​​are selected to maintain high precision and consistency. The narrowed output drive pulse drives the gate driver for power amplification, further driving the GaN FET device to rapidly turn on and off, thereby achieving high-voltage narrow pulse output. The programmable delay circuit is implemented in the core chip IC1 (DS1124).

[0082] Furthermore, the Balun transformer has a center tap on the primary side, with the two ports on the primary side connected to high-voltage narrow pulse outputs, and the center tap grounded. The primary-to-secondary turns ratio is 2:1, and the effective frequency range is 5-300MHz. Furthermore, due to the magnetizing inductance characteristics of the Balun transformer, the leakage inductance needs to be minimized to increase the upper frequency limit. Furthermore, due to the transformer's self-inductance coupling, the rated operating voltage of the GaN FET needs to be greater than twice the high-voltage power supply voltage to prevent damage to the GaN FET from reverse inrush voltage.

[0083] After testing, high voltage bipolar pulse waveforms such as Figure 10 As shown in the figure, it can achieve an effective excitation pulse with a frequency greater than 100 MHz and a peak voltage greater than 100 V. Its peak voltage is 110 V and the center frequency is 103 MHz. Example 2

[0084] An echo protection circuit, such as Figure 1-Figure 2 、 Figure 7-Figure 8 As shown, it is used to prevent the high-voltage pulse output by the above-mentioned high-frequency ultrasonic pulse excitation generator from damaging the low-voltage receiving circuit. For a detailed description of the high-frequency ultrasonic pulse excitation generator, please refer to the corresponding description in the above-mentioned high-frequency ultrasonic pulse excitation generator embodiment, which will not be repeated here.

[0085] For T / R switch circuits, existing circuits face the problem of high on-resistance and insertion loss in high-frequency ultrasonic applications, resulting in large echo attenuation in the receiving path. The relay mode has a slow switching speed, which affects the ultrasonic PRF and increases the near-field blind area. This embodiment designs a special control of the T / R switch function using a high-voltage analog multiplexing switch, which achieves fast response switching while achieving low insertion loss. The high-voltage analog multiplexing switch includes a shift register, a cache, a level conversion module, and a high-voltage switch. In the ultrasonic imaging circuit, the multiplexing switch is used to reduce the number of hardware channels of a multi-element probe. When the number of transducer arrays is much larger than the number of system channels, the sub-array elements and system channels are selectively connected through the multiplexing switch, thereby greatly reducing the front-end wiring, circuit size and cost. By utilizing the characteristics of the high-voltage analog multiplexing switch to isolate transmission and realize reception, and achieve faster switching response. The internal working process of the high-voltage analog multiplexing switch is as follows. Figure 7 As shown, the switch control data is input into the register and corresponding buffer, waiting for the switch trigger signal to change. Once the signal changes, the high-voltage switch activates and changes state. The entire process takes 2-3 μs. The high-voltage switch is in the off state by default. When the high-voltage pulse transmission is completed and the switch control process is restarted, there is a 2-3 μs period during which no echo is received, which significantly affects high-frequency ultrasound imaging.

[0086] Therefore, this embodiment optimizes the control process, such as Figure 8-Figure 9 As shown, it mainly includes two aspects: (1) the register data that requires the high-voltage switch to operate is pre-stored before the pulse is transmitted, saving the intermediate time between the end of transmission and the reception of the echo; on the other hand, since the high-voltage switch operation process also takes a certain amount of time, the pulse transmission output is delayed, and the controllable delay of the pulse transmission is achieved through the above-mentioned programmable delay circuit 1. The transmission pulse output is realized in the middle of the high-voltage switch conversion process. At this time, the high-voltage switch is still disconnected and has not yet been turned off. Therefore, after the pulse transmission is completed, the high-voltage switch action is completed immediately, further shortening the unreceivable time between transmission and reception.

[0087] Specifically, this embodiment selects TMUX9616 as the T / R switch signal, and uses the above method to compress the switching time effect to within 1us, thereby achieving good echo reception capability. And compare the signal insertion loss of the traditional T / R switch and the switch designed in this embodiment, the loss value comparison is as follows: Figure 11 shown. Figure 11 This shows that the T / R switch designed in this embodiment has better signal passing capability. Example 3

[0088] A high-frequency ultrasound imaging system, such as Figures 1-9As shown, the high-frequency ultrasonic pulse excitation generator and the echo protection circuit are included. The echo protection circuit is used to prevent the high-voltage pulses output by the high-frequency ultrasonic pulse excitation generator from damaging the low-voltage receiving circuit. For detailed descriptions of the high-frequency ultrasonic pulse excitation generator and the echo protection circuit, reference can be made to the corresponding descriptions in the above-mentioned high-frequency ultrasonic pulse excitation generator embodiment and the above-mentioned echo protection circuit embodiment, and will not be repeated here. Example 4

[0089] A control method for a high-frequency ultrasonic imaging system is provided, based on the above-mentioned high-frequency ultrasonic imaging system. For a detailed description of the high-frequency ultrasonic imaging system, reference may be made to the corresponding description in the above-mentioned embodiment of the high-frequency ultrasonic imaging system, which will not be repeated here.

[0090] When the high-voltage pulse transmission is completed and the switch action control process is started, there will be a 2-3us area where the echo cannot be received, which has a great impact on high-frequency ultrasonic imaging. Therefore, this embodiment optimizes the control method, such as Figure 8-Figure 9 As shown, the method includes the following steps:

[0091] Before the pulse is transmitted, the register data that requires the high-voltage switch action is pre-stored to save the intermediate time between the end of transmission and the reception of echo;

[0092] Since the high-voltage switch action process also takes a certain amount of time, the pulse transmission output is delayed. The controllable delay of the pulse transmission is achieved through the above-mentioned programmable delay circuit 1. The pulse transmission output is achieved in the middle of the high-voltage switch conversion process. At this time, the high-voltage switch is still disconnected and has not yet been turned off. Therefore, after the pulse transmission is completed, the high-voltage switch action is completed immediately, further shortening the unreceivable time between transmission and reception. Example 5

[0093] A computer device 300, such as Figure 12 As shown, the system includes a memory 310, a processor 320, and a computer program 330 stored in the memory and executable on the processor. When the processor executes the computer program, the steps of a method for controlling a high-frequency ultrasound imaging system are implemented. For a detailed description of the method, please refer to the corresponding description in the above method embodiment and will not be repeated here. Example 6

[0094] A computer-readable storage medium such as Figure 13 As shown, a computer program is stored thereon, and when the computer program is executed by the processor, the steps of a control method of a high-frequency ultrasonic imaging system are implemented. For a detailed description of the method, reference can be made to the corresponding description in the above method embodiment, and no further details will be given here.

[0095] The number of devices and processing scales described herein are intended to simplify the description of the present invention. Applications, modifications, and variations of the present invention will be readily apparent to those skilled in the art.

[0096] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the description and implementation methods. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

[0097] The apparatus, computer device, non-volatile computer storage medium, and method provided in the embodiments of this specification correspond to each other. Therefore, the apparatus, computer device, and non-volatile computer storage medium also have similar beneficial technical effects as the corresponding method. Since the beneficial technical effects of the method have been described in detail above, the beneficial technical effects of the corresponding apparatus, computer device, and non-volatile computer storage medium will not be repeated here.

[0098] Those skilled in the art will also appreciate that, in addition to implementing the controller in pure computer-readable program code, it is entirely possible to implement the same functionality by programming the method steps logically, such as through logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers. Therefore, such a controller can be considered a hardware component, and the devices included therein for implementing various functions can also be considered structures within the hardware component. Alternatively, the devices for implementing various functions can be considered both software units implementing the method and structures within the hardware component.

[0099] The systems, devices, or units described in the above embodiments can be implemented by computer chips or physical devices, or by products with certain functions. For ease of description, the above devices are described separately by function, with each unit described separately. Of course, when implementing one or more embodiments of this specification, the functions of each unit can be implemented in the same or multiple software and / or hardware components.

[0100] Those skilled in the art will appreciate that the embodiments of this specification may be provided as methods, systems, or computer program products. Thus, the embodiments of this specification may take the form of entirely hardware embodiments, entirely software embodiments, or embodiments combining software and hardware. Furthermore, the embodiments of this specification may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0101] This specification is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of this specification. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0102] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0103] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0104] It should also be noted that the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, commodity, or apparatus that includes a series of elements includes not only those elements but also other elements not explicitly listed, or includes elements inherent to such process, method, commodity, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, commodity, or apparatus that includes the element.

[0105] This specification may be described in the general context of computer-executable instructions executed by a computer, such as program units. Generally, program units include routines, programs, objects, components, data structures, and the like that perform specific tasks or implement specific abstract data types. The specification may also be practiced in distributed computing environments where tasks are performed by remote processing devices connected via a communications network. In a distributed computing environment, program units may be located in local and remote computer storage media, including storage devices.

[0106] The various embodiments in this specification are described in a progressive manner. Similar parts between the various embodiments can be referred to in conjunction with each other. Each embodiment focuses on the differences between the other embodiments. In particular, the system embodiments are generally similar to the method embodiments, so the description is relatively simple. For relevant parts, refer to the description of the method embodiments.

[0107] The foregoing is merely an example of the present invention and is not intended to limit the present invention to one or more embodiments. It will be apparent to those skilled in the art that various modifications and variations may be made to the present invention to one or more embodiments. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention to one or more embodiments shall be included within the scope of the claims of the present invention to one or more embodiments.

Claims

1. An ultrasonic pulse generator, characterized in that: It includes two unipolar high-frequency high-voltage pulse circuits and Balun transformers; The unipolar high-frequency and high-voltage pulse circuit includes a programmable delay circuit, a narrowed driving pulse circuit, and a high-frequency and high-voltage pulse generating circuit; The programmable delay circuit is used to delay the input pulse; The narrowed driving pulse circuit is used to generate a trigger signal with a minimum pulse width of 1 ns and an adjustable pulse width, thereby controlling the high-frequency and high-voltage pulse generating circuit to output a high-voltage narrow pulse; The Balun transformer is used to couple and output high-voltage narrow pulses output by two unipolar high-frequency high-voltage pulse circuits; The narrowed drive pulse circuit includes a NOT gate, a programmable delay chip, a first AND gate, a second AND gate and an RC circuit. The wide pulse signal is input through the NOT gate, the output end of the NOT gate is connected to the first input end of the first AND gate, the programmable delay chip is connected to the input end of the NOT gate and the second input end of the first AND gate, the output end of the first AND gate is connected to the first input end of the second AND gate, the output end of the first AND gate is connected to the second input end of the second AND gate via the RC circuit, and the output end of the second AND gate is connected to the high-frequency and high-voltage pulse generating circuit.

2. The ultrasonic pulse generator according to claim 1, wherein: The device also includes a limiting circuit, which is used to effectively output a high-voltage pulse signal and prevent the echo signal from entering the transmitting circuit.

3. The ultrasonic pulse generator according to claim 2, wherein: The limiting circuit is arranged between the high-frequency and high-voltage pulse generating circuit and the primary side of the Balun transformer.

4. The ultrasonic pulse generator according to claim 2, wherein: The limiting circuit is arranged between the secondary side of the Balun transformer and the echo protection circuit.

5. The ultrasonic pulse generator according to claim 2, wherein: The high-frequency, high-voltage pulse generating circuit includes a gate driver, a gate driving resistor, a GaN-based transistor, a first resistor, and a capacitor. The gate driver is connected to the base of the transistor via the gate driving resistor, the emitter of the transistor is grounded, and the collector of the transistor is connected to the power supply via the first resistor and to the limiting circuit via the capacitor.

6. The ultrasonic pulse generator according to claim 5, characterized in that: The limiting circuit is implemented by using series diodes.

7. The ultrasonic pulse generator according to claim 1, wherein: The delay times of the programmable delay circuits in the two unipolar high-frequency and high-voltage pulse circuits are not equal, and the delay time difference is determined by the pulse width of the output pulse of the narrowed drive pulse circuit and is not less than the pulse width of the output pulse of the narrowed drive pulse circuit.

8. The ultrasonic pulse generator according to claim 7, wherein: The output pulse width of the narrowed driving pulse circuit is controlled by an internal programmable delay chip.

9. The ultrasonic pulse generator according to claim 1, wherein: The Balun transformer has a center tap on the primary side, two ports on the primary side are respectively connected to high-voltage narrow pulse outputs, the center tap is grounded, and the turns ratio between the primary side and the secondary side is 2:

1. The effective frequency coverage range is 5-300MHz.

10. The ultrasonic pulse generator according to claim 5, characterized in that: The rated operating voltage of the transistor is greater than twice the voltage of the high-voltage power supply to prevent the transistor from being damaged by a reverse surge voltage.

11. An echo protection circuit for preventing the high-voltage pulse output by the ultrasonic pulse generator according to claim 1 from damaging a low-voltage receiving circuit, characterized in that: The T / R switch function is realized by using a high-voltage analog multiplexing switch, wherein the high-voltage analog multiplexing switch includes a shift register, a buffer, a level conversion module, and a high-voltage switch; wherein, The switch control data is input into the shift register and the corresponding buffer, waiting for the switch trigger signal to change. After the signal changes, the high-voltage switch starts to operate to realize the state change.

12. The echo protection circuit according to claim 11, characterized in that: The high voltage switch is in the disconnected state by default.

13. An ultrasonic imaging system, characterized in that: It comprises the ultrasonic pulse generator according to claim 1 and the echo protection circuit according to claim 11, wherein the echo protection circuit is used to prevent the high-voltage pulse output by the ultrasonic pulse generator from damaging the low-voltage receiving circuit.

14. A control method for an ultrasonic imaging system, based on the ultrasonic imaging system according to claim 13, characterized in that: The following steps are involved: Before the pulse is emitted, the register data that requires the high-voltage switch action is pre-stored; The controllable delay of pulse emission is achieved through a programmable delay circuit, and the pulse emission output is achieved in the middle of the conversion process of the high-voltage switch.

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