A phased array ultrasonic transducer excitation system for increasing amplitude

Abstract

The present invention discloses a phased array ultrasonic transducer excitation system for increasing amplitude, wherein a PC in the system is used to provide focus excitation parameters of each channel of the phased array ultrasonic transducer, an FPGA focus delay module is used to calculate the focus delay data of each channel according to the focus excitation parameters of each channel, and outputs a PWM wave carrying the focus delay data corresponding to each channel in combination with the focus delay data of each channel, and the PWM wave carrying the focus delay data corresponding to each channel is input into the corresponding baseband control circuit through an I / O channel expansion module, and each LC oscillation circuit oscillates a DC source signal into a sine wave signal according to the baseband signal output by the baseband control circuit and outputs it to the corresponding channel of the phased array ultrasonic transducer. By exciting a high-amplitude sine wave with zero high-frequency component through the excitation system, load heating and piezoelectric ceramic vibration loss can be reduced, and the service life of the phased array ultrasonic transducer can be significantly improved.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of phased array ultrasonic transducers, and in particular to a phased array ultrasonic transducer excitation system for increasing amplitude. Background Art

[0002] Brain science neuromodulation technology is a biomedical engineering technology that uses implantable or non-implantable technology to change the activity of the nervous system by physical stimulation or drug means, thereby improving the patient's disease symptoms and improving the quality of life. In addition to the application of drugs, the technology of neurostimulation based on physical factors such as electricity, magnetism, light, and sound plays an important role in the basic research of neuroscience and the clinical diagnosis and treatment of neurological and mental diseases. Magnetoacoustic coupling electrical stimulation technology (TMAS) is a kind of neuromodulation technology. Based on the magnetoacoustic coupling effect, biological tissues contain conductive particles, which vibrate under the action of ultrasound. The vibrating particles are subjected to the Lorentz force in the magnetic field to generate a coupled electric field. This technology uses the high focusing characteristics of ultrasound to achieve non-invasive electrical stimulation with high spatial resolution under the condition of loading a magnetic field. This method has good safety, no permanent side effects, is adjustable, non-invasive or minimally invasive, and the stimulation is reversible. It has great development prospects in brain function research. However, studies have shown that the TMAS compound effect still has not reached the electrical stimulation threshold of neural activity. How to enhance the TMAS electric field and further enhance the compound stimulation effect is the core key issue.

[0003] The traditional ultrasonic transducer excitation source system uses high-voltage and high-frequency square waves for excitation, but the high-frequency component of the square wave will cause heating and damage to the ultrasonic transducer. In addition, since the power amplifier based on PWM amplification usually needs to set a dead zone, the waveform accuracy is low, the actual excitation waveform is not a standard square wave or a standard sine wave, and it cannot transmit a pulse signal with an accurate frequency. Summary of the invention

[0004] The present invention provides a phased array ultrasonic transducer excitation system for increasing amplitude, so that a high-amplitude sine wave with zero high-frequency component can be excited through the excitation system, load heating and piezoelectric ceramic vibration loss can be reduced, and the service life of the phased array ultrasonic transducer can be significantly increased.

[0005] To achieve the above object, an embodiment of the present invention proposes a phased array ultrasonic transducer excitation system for increasing amplitude, comprising:

[0006] A PC, an FPGA focus delay module, an I / O channel expansion module, a plurality of baseband control circuits and a plurality of LC oscillation circuits, wherein the baseband control circuits correspond to the LC oscillation circuits one by one;

[0007] The PC is used to provide focus excitation parameters for each channel of the phased array ultrasonic transducer. The FPGA focus delay module is used to calculate the focus delay data of each channel according to the focus excitation parameters of each channel, and output a PWM wave carrying the focus delay data corresponding to each channel in combination with the focus delay data of each channel. The PWM wave carrying the focus delay data corresponding to each channel is input into the corresponding baseband control circuit through the I / O channel expansion module. Each of the LC oscillation circuits oscillates the DC source signal into a sinusoidal wave signal based on the baseband signal output by the baseband control circuit and outputs it to the corresponding channel of the phased array ultrasonic transducer.

[0008] According to one embodiment of the present invention, the baseband control circuit includes:

[0009] An optocoupler circuit unit, a NAND gate circuit unit, a crystal oscillator unit, a MOS tube control unit and a MOS tube, wherein the input end of the optocoupler circuit unit is connected to the I / O channel expansion module, the output end of the optocoupler circuit unit is connected to the input end of the NAND gate circuit unit, the output end of the crystal oscillator unit is connected to the input end of the NAND gate circuit unit, the output end of the NAND gate circuit unit is connected to the MOS tube control unit, and the MOS tube is in an open state or a closed state according to the level signal output by the MOS tube control unit to provide a baseband signal for the LC oscillation circuit.

[0010] According to one embodiment of the present invention, the optocoupler circuit unit includes: a first power supply chip, an optocoupler and a first capacitor, the first end and the second end of the optocoupler respectively input the PWM wave signal, the third end of the optocoupler is connected to the output end of the first power supply chip, the fourth end of the optocoupler is grounded, the fifth end of the optocoupler is connected to the NAND gate circuit unit, the first power supply chip supplies power to the optocoupler, the output end of the first power supply chip is also connected to one end of the first capacitor, and the other end of the first capacitor is grounded.

[0011] According to an embodiment of the present invention, the NAND gate circuit unit includes: a first NAND gate, a second NAND gate, a third NAND gate and a first resistor, wherein a first input terminal of the first NAND gate is connected to one end of the first resistor, the other end of the first resistor is connected to a second power supply, a first input terminal of the first NAND gate is connected to a second input terminal, and a second input terminal of the first NAND gate is connected to a fifth end of the optocoupler;

[0012] The output end of the first NAND gate is connected to the first input end of the second NAND gate, the second input end of the second NAND gate is connected to the crystal oscillator unit, the output end of the second NAND gate is respectively connected to the first input end and the second input end of the third NAND gate, and the output end of the third NAND gate is connected to the input end of the MOS tube control unit.

[0013] According to one embodiment of the present invention, the crystal oscillator unit includes: a fourth NAND gate, a second resistor, a third resistor, a second capacitor, a third capacitor and a fourth capacitor, one end of the second capacitor and the third capacitor are both grounded, the other end of the second capacitor is connected to one end of the fourth capacitor, the other end of the third capacitor is connected to the other end of the fourth capacitor, the other end of the fourth capacitor is also connected to one end of the second resistor, the other end of the second resistor is connected to the output end of the fourth NAND gate, one end of the fourth capacitor is also connected to the first input end and the second input end of the fourth NAND gate, one end of the third resistor is connected to the first input end and the second input end of the fourth NAND gate, the other end of the third resistor is connected to the output end of the fourth NAND gate, and the output end of the fourth NAND gate is connected to the second input end of the second NAND gate.

[0014] According to an embodiment of the present invention, the MOS tube control unit includes: a fourth resistor, a fifth resistor, a sixth resistor, a fifth capacitor, a sixth capacitor, a first switch tube and a second switch tube, wherein one end of the fourth resistor and the fifth capacitor connected in parallel is connected to the output end of the third NAND gate, and the other end is respectively connected to the control end of the first switch tube and the second switch tube, the source of the first switch tube is connected to the third power supply and one end of the sixth capacitor, the other end of the sixth capacitor is grounded, the drain of the first switch tube is respectively connected to the drain of the second switch tube and one end of the fifth resistor, the source of the second switch tube is grounded, the other end of the fifth resistor is respectively connected to the control end of the MOS tube and one end of the sixth resistor, and the other end of the sixth resistor is grounded.

[0015] According to one embodiment of the present invention, the LC oscillation circuit includes a first LC oscillation circuit unit and a second LC oscillation circuit unit, the input end of the first LC oscillation circuit unit is used to input the DC source signal, the output end of the first LC oscillation circuit is respectively connected to the input end of the second LC oscillation circuit and the second end of the MOS tube, the third end of the MOS tube is grounded, and the output end of the second LC oscillation circuit is connected to the corresponding array element of the phased array ultrasonic transducer.

[0016] According to one embodiment of the present invention, the first LC oscillation circuit unit includes: a Wheatstone bridge, a seventh capacitor, an eighth capacitor, a ninth capacitor, a seventh resistor, a first inductor, and a first diode. The first end and the second end of the Wheatstone bridge are respectively connected to the DC source signal, the fourth end of the Wheatstone bridge is grounded, the third end of the Wheatstone bridge is respectively connected to one end of the seventh capacitor and one end of the seventh resistor, the other end of the seventh capacitor is grounded, the other end of the seventh resistor is respectively connected to a fourth power supply and a cathode of a first diode, the anode of the first diode is connected to a first end of the first inductor, the second end of the first inductor is grounded, the third end of the first inductor is respectively connected to one end of the eighth capacitor and one end of the seventh capacitor, the other end of the eighth capacitor is grounded, the fourth end of the first inductor is respectively connected to one end of the ninth capacitor and the second LC oscillation circuit unit, and the other end of the ninth capacitor is grounded.

[0017] According to one embodiment of the present invention, the second LC oscillation circuit unit includes: a tenth capacitor, an eleventh capacitor, a twelfth capacitor, a thirteenth capacitor, a fourteenth capacitor, an eighth resistor, a ninth resistor, a tenth resistor, a second inductor, and a second diode, one end of the tenth capacitor is connected to the other end of the ninth capacitor, the other end of the tenth capacitor is connected to the first end of the second inductor, the second end of the second inductor is connected to the anode of the second diode, the cathode of the second diode is connected to one end of the eighth resistor, the other end of the eighth resistor is connected to one end of the ninth resistor and the eleventh capacitor in parallel, and the ninth resistor and the eleventh resistor are connected to each other. The other end of the capacitors connected in parallel is connected to the third end of the second inductor, the fourth ends of the second inductors are respectively connected to one end of the twelfth capacitor, the other end of the twelfth capacitor is connected to one end of the thirteenth capacitor, the other end of the twelfth capacitor is grounded, the other end of the thirteenth capacitor is connected to one end of the tenth resistor, one end of the tenth resistor is grounded, the other end of the tenth resistor is connected to the other end of the ninth resistor and the eleventh capacitor in parallel, the fourth end of the second inductor is also connected to one end of the fourteenth capacitor, the other end of the fourteenth capacitor is grounded, and one end of the fourteenth capacitor is connected to the phased array ultrasonic transducer.

[0018] According to one embodiment of the present invention, the phased array ultrasonic transducer excitation system for increasing amplitude further includes:

[0019] A hardware delay compensation module, wherein the input end of the hardware delay compensation module is connected to the output ends of the plurality of LC oscillation circuits, and the output end of the hardware delay compensation module is connected to the phased array ultrasonic transducer.

[0020] According to an embodiment of the present invention, a phased array ultrasonic transducer excitation system for increasing amplitude includes: a PC, an FPGA focus delay module, an I / O channel expansion module, multiple baseband control circuits and multiple LC oscillation circuits, wherein the baseband control circuits correspond to the LC oscillation circuits one by one; the PC is used to provide focus excitation parameters of each channel of the phased array ultrasonic transducer, the FPGA focus delay module is used to calculate the focus delay data of each channel according to the focus excitation parameters of each channel, and output a PWM wave carrying the focus delay data corresponding to each channel in combination with the focus delay data of each channel, the PWM wave carrying the focus delay data corresponding to each channel is input into the corresponding baseband control circuit through the I / O channel expansion module, and each LC oscillation circuit oscillates a DC source signal into a sine wave signal according to the baseband signal output by the baseband control circuit and outputs it to the corresponding channel of the phased array ultrasonic transducer. The excitation system can excite a high-amplitude sine wave with zero high-frequency component, reduce load heating and piezoelectric ceramic vibration loss, and significantly improve the service life of the phased array ultrasonic transducer. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a block diagram of a phased array ultrasonic transducer excitation system for increasing amplitude proposed in an embodiment of the present invention;

[0022] Figure 2 is a block diagram of a phased array ultrasonic transducer excitation system for increasing amplitude proposed by one embodiment of the present invention;

[0023] Figure 3 is a circuit schematic diagram of a phased array ultrasonic transducer excitation system for increasing amplitude proposed by one embodiment of the present invention;

[0024] Figure 4 It is a block diagram of a phased array ultrasonic transducer excitation system for increasing amplitude proposed by another embodiment of the present invention. DETAILED DESCRIPTION

[0025] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0026] In experiments related to transcranial ultrasonic nerve stimulation, most of the ultrasonic transducers used are single-element ultrasonic transducers. This type of transducer has only one working element and has no focusing function by itself. It needs to be assisted by an acoustic lens or an acoustic collimator for focusing. The most commonly used acoustic lens is a spherical focusing lens, which has the best focusing characteristics. If hardware focusing is performed with the help of an acoustic collimator, the focusing result is not controlled by the transducer characteristics but is determined by the acoustic collimator parameters. If multiple sets of experiments are conducted, the acoustic collimator needs to be replaced frequently.

[0027] Due to the insufficient number of elements in traditional single-element ultrasonic transducers, there is a focusing bottleneck in the focusing process. Therefore, recent studies have begun to use phased array ultrasonic transducers for transcranial stimulation research. The ultrasonic phased array is a plurality of piezoelectric crystals arranged in a certain distribution. Then, each element can be excited by a program-controlled method according to a predetermined delay time to achieve the purpose of scanning, deflection, and focusing of the sound wave. In the process of achieving precise focusing, the phased array ultrasonic transducer can use the advantage of multiple elements being phase-controlled to focus the emitted sound waves in one area, forming superimposed energy, and thus its focusing performance can be doubled compared to the single-element ultrasonic transducer. And because each beam is superimposed at the focus, the signal-to-noise ratio of the detection signal has also been significantly improved. In order to achieve dynamic focusing and deflection of the beam, a multi-channel ultrasonic phased array transmitting system is required to excite each element according to a predetermined delay time.

[0028] The existing technology has the following disadvantages: (1) The traditional ultrasonic transducer excitation source system uses high-voltage and high-frequency square waves for excitation. The high-frequency component of the square wave will cause heating and damage to the ultrasonic transducer. (2) Since the power amplifier based on PWM amplification usually needs to set a dead zone, the waveform accuracy is low. The actual excitation waveform is not a standard square wave or a standard sine wave, and it cannot emit a pulse signal with an accurate frequency. (3) The traditional excitation device has a small number of channels, and usually can only excite 8-16 channels at the same time.

[0029] Therefore, in order to solve the above problems, the present invention proposes a phased array ultrasonic transducer excitation system for increasing the amplitude.

[0030] Figure 1 is a block diagram of a phased array ultrasonic transducer excitation system for increasing amplitude proposed in an embodiment of the present invention. Figure 1 As shown, the phased array ultrasonic transducer excitation system 100 for increasing amplitude includes:

[0031] PC 101, FPGA focus delay module 102, I / O channel expansion module 103, multiple baseband control circuits and multiple LC oscillation circuits, baseband control circuit 104 corresponds to LC oscillation circuit 105 one by one;

[0032] The PC 101 is used to provide focus excitation parameters for each channel of the phased array ultrasonic transducer 106. The FPGA focus delay module 102 is used to calculate the focus delay data of each channel according to the focus excitation parameters of each channel, and output a PWM wave carrying the focus delay data corresponding to each channel in combination with the focus delay data of each channel. The PWM wave carrying the focus delay data corresponding to each channel is input into the corresponding baseband control circuit 104 through the I / O channel expansion module 103. Each LC oscillation circuit 105 oscillates the DC source signal into a sinusoidal wave signal according to the baseband signal output by the baseband control circuit 104 and outputs it to the corresponding channel of the phased array ultrasonic transducer 106.

[0033] It can be understood that the focusing excitation parameters of each channel of the phased array ultrasonic transducer, such as the number of excitation array elements, array element width, array element spacing, excitation ultrasonic propagation medium, etc., are controlled by a PC using Quartus_Prime software. The FPGA focusing delay module 102 calculates the focusing delay data of each channel according to the focusing excitation parameters of each channel, and outputs a PWM wave carrying the focusing delay data corresponding to each channel in combination with the focusing delay data of each channel. The PWM wave corresponding to each channel controls the corresponding baseband control circuit 104 to output a baseband signal to the corresponding LC oscillation circuit 105, so that the LC oscillation circuit 105 oscillates the DC source signal into a sine wave signal based on the baseband signal, and outputs it to the corresponding channel of the phased array ultrasonic transducer 106 for each array element to work. The use of this excitation system can excite a high-amplitude sine wave. Since the sine wave has a zero high-frequency component, it can reduce load heating and piezoelectric ceramic vibration loss, and can significantly improve the service life of the phased array ultrasonic transducer.

[0034] It should be noted that the PWM wave output by the FPGA focus delay module 102 only controls the baseband control circuit 104 to output the baseband signal to the corresponding LC oscillator circuit 105, so that the LC oscillator circuit 105 can oscillate the DC source signal into a sine wave signal. The PWM wave not only carries the focus delay information, but also controls the duty cycle of the phased array ultrasonic transducer excitation pulse. The main frequency of the module can reach 250MHz, and it supports a delay with a maximum accuracy of 4ns, which can accurately modulate the excitation waveform.

[0035] According to one embodiment of the present invention, Figure 2 As shown, the baseband control circuit 104 includes:

[0036] The optocoupler circuit unit 107, the NAND gate circuit unit 108, the crystal oscillator unit 109, the MOS tube control unit 110 and the MOS tube 111, the input end of the optocoupler circuit unit 107 is connected to the I / O channel expansion module 103, the output end of the optocoupler circuit unit 107 is connected to the input end of the NAND gate circuit unit 108, the output end of the crystal oscillator unit 109 is connected to the input end of the NAND gate circuit unit 108, the output end of the NAND gate circuit unit 108 is connected to the MOS tube control unit 110, and the MOS tube 111 is in an open state or a closed state according to the level signal output by the MOS tube control unit 110, so as to provide a baseband signal for the LC oscillation circuit 105.

[0037] It should be noted that after receiving external pressure, the crystal oscillator unit 109 generates an electrical signal, that is, a baseband signal. The optocoupler circuit unit 107 receives the PWM signal output by the FPGA focus delay module 102. The optocoupler in the optocoupler circuit unit 107 is in an on state or an off state depending on the level of the PWM wave signal, that is, the "0 or 1" state is input to the input end of the NAND gate circuit unit 108. The baseband signal "1" generated by the crystal oscillator unit 109 is input to the input end of the NAND gate circuit unit 108. Since the output end of the NAND gate circuit unit 108 is connected to the control end of the MOS tube control unit 110, the signal output by the optocoupler circuit unit 107 controlled by the PWM signal and the baseband signal generated by the crystal oscillator unit 109 are output as a control signal to the control end of the MOS tube control unit 110 after passing through the NAND gate circuit unit 108, and when the MOS tube is turned on, the baseband signal is provided to the LC oscillation circuit 105.

[0038] The structure and principle of the circuit are introduced in detail below.

[0039] According to one embodiment of the present invention, Figure 3 As shown, the optocoupler circuit unit 107 includes: a first power chip 112, an optocoupler 113 and a first capacitor C1, the first end 1 and the second end 2 of the optocoupler 113 respectively input PWM wave signals, the third end 3 of the optocoupler 113 is connected to the output end of the first power chip 112, the fourth end 4 of the optocoupler 113 is grounded, the fifth end 5 of the optocoupler 113 is connected to the NAND gate circuit unit 108, the first power chip 112 supplies power to the optocoupler 113, the output end of the first power chip 112 is also connected to one end of the first capacitor C1, and the other end of the first capacitor C1 is grounded.

[0040] The first power chip 112 supplies power to the optocoupler 113. When the first end 1 of the optocoupler 113 inputs a high level and the second end 2 inputs a low level, the optocoupler 113 is turned on. Conversely, when the first end 1 of the optocoupler 113 inputs a low level and the second end 2 inputs a high level, the optocoupler 113 is turned off. In other words, the PWM waves input by the first end 1 and the second end 2 of the optocoupler 113 differ by half a cycle. When the optocoupler 113 is turned on, the fifth end 5 of the optocoupler 113 outputs a high level. When the optocoupler 113 is turned off, the fifth end 5 of the optocoupler 113 outputs a low level.

[0041] According to one embodiment of the present invention, Figure 3 As shown, the NAND gate circuit unit 108 includes: a first NAND gate 114, a second NAND gate 115, a third NAND gate 116 and a first resistor R1, a first input terminal 1 of the first NAND gate 114 is connected to one end of the first resistor R1, the other end of the first resistor R1 is connected to the second power supply VDD2, the first input terminal 1 of the first NAND gate 114 is connected to the second input terminal 2, and the second input terminal 2 of the first NAND gate 114 is connected to the fifth terminal 5 of the optical coupler 113;

[0042] The output end 3 of the first NAND gate 114 is connected to the first input end 1 of the second NAND gate 115, the second input end 2 of the second NAND gate 115 is connected to the crystal oscillator unit 109, the output end 3 of the second NAND gate 115 is respectively connected to the first input end 1 and the second input end 2 of the third NAND gate 116, and the output end 3 of the third NAND gate 116 is connected to the input end of the MOS tube control unit 110.

[0043] Among them, when the optocoupler 113 is turned on, the fifth terminal 5 of the optocoupler 113 outputs a high level, which is then input to the second input terminal 2 of the first NAND gate 114. The first input terminal 1 and the second input terminal 2 of the first NAND gate 114 are both high levels, and then the output terminal 3 of the first NAND gate 114 outputs a low level. When the optocoupler 113 is turned off, the fifth terminal 5 of the optocoupler 113 outputs a low level, which is then input to the second input terminal 2 of the first NAND gate 114. The first input terminal 1 and the second input terminal 2 of the first NAND gate 114 are both low levels, and at this time, the output terminal 3 of the first NAND gate 114 outputs a high level.

[0044] When the output terminal 3 of the first NAND gate 114 is at a high level, that is, the first input terminal 1 of the second NAND gate 115 is at a high level, if the second input terminal 2 of the second NAND gate 115 is at a low level, then the output terminal 3 of the second NAND gate 115 is at a high level; if the second input terminal 2 of the second NAND gate 115 is at a high level, then the output terminal 3 of the second NAND gate 115 is at a low level.

[0045] When the output terminal 3 of the first NAND gate 114 is at a low level, that is, the first input terminal 1 of the second NAND gate 115 is at a low level, if the second input terminal 2 of the second NAND gate 115 is at a low level, then the output terminal 3 of the second NAND gate 115 is at a high level; if the second input terminal 2 of the second NAND gate 115 is at a high level, then the output terminal 3 of the second NAND gate 115 is at a high level.

[0046] When the output terminal 3 of the second NAND gate 115 is at a high level, the first input terminal 1 and the second input terminal 2 of the third NAND gate 116 are both at a high level, and the output terminal 3 of the third NAND gate 116 is at a low level. When the output terminal 3 of the second NAND gate 115 is at a low level, the first input terminal 1 and the second input terminal 2 of the third NAND gate 116 are both at a low level, and the output terminal 3 of the third NAND gate 116 is at a high level.

[0047] According to one embodiment of the present invention, Figure 3 As shown, the crystal oscillator unit 109 includes: a fourth NAND gate 117, a second resistor R2, a third resistor R3, a second capacitor C2, a third capacitor C3 and a fourth capacitor C4, one end of the second capacitor C2 and the third capacitor C3 are both grounded, the other end of the second capacitor C2 is connected to one end of the fourth capacitor C4, the other end of the third capacitor C3 is connected to the other end of the fourth capacitor C4, the other end of the fourth capacitor C4 is also connected to one end of the second resistor R2, the other end of the second resistor R2 is connected to the output end 3 of the fourth NAND gate 117, one end of the fourth capacitor C4 is also connected to the first input end 1 and the second input end 2 of the fourth NAND gate 117, one end of the third resistor R3 is connected to the first input end 1 and the second input end 2 of the fourth NAND gate 117, the other end of the third resistor R3 is connected to the output end 3 of the fourth NAND gate 117, and the output end of the fourth NAND gate 117 is connected to the second input end 2 of the second NAND gate 115.

[0048] Among them, when the second capacitor C2, the third capacitor C3 and the fourth capacitor C4 are charged, the first input terminal 1 and the second input terminal 2 of the fourth NAND gate 117 are both high level, and the output terminal 3 is low level; when the second capacitor C2, the third capacitor C3 and the fourth capacitor C4 are fully charged, the first input terminal 1 and the second input terminal 2 of the fourth NAND gate 117 are both low level, and the output terminal 3 is high level; when the second capacitor C2, the third capacitor C3 and the fourth capacitor C4 are fully charged and discharged, the first input terminal 1 and the second input terminal 2 of the fourth NAND gate 117 are both high level, and the output terminal 3 is low level.

[0049] According to one embodiment of the present invention, Figure 3As shown, the MOS tube control unit 110 includes: a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a fifth capacitor C5, a sixth capacitor C6, a first switch tube Q1 and a second switch tube Q2, wherein one end of the fourth resistor R4 and the fifth capacitor C5 connected in parallel is connected to the output end 3 of the third NAND gate 116, and the other end is respectively connected to the control end of the first switch tube Q1 and the second switch tube Q2, the source of the first switch tube Q1 is connected to the third power supply VDD3 and one end of the sixth capacitor C6, the other end of the sixth capacitor C6 is grounded, the drain of the first switch tube Q1 is respectively connected to the drain of the second switch tube Q2 and one end of the fifth resistor R5, the source of the second switch tube Q2 is grounded, the other end of the fifth resistor R5 is respectively connected to the control end of the MOS tube 111 and one end of the sixth resistor R6, and the other end of the sixth resistor R6 is grounded.

[0050] Among them, the first switch tube Q1 is an NPN transistor, the second switch tube Q2 is a PNP transistor, and the MOS tube 111 is an NMOS tube. When the output terminal 3 of the third NAND gate 116 outputs a high level, the first switch tube Q1 is turned on, the second switch tube Q2 is turned off, and the MOS tube 111 is turned on. When the output terminal 3 of the third NAND gate 116 outputs a low level, the first switch tube Q1 is turned off, the second switch tube Q2 is turned off, and the MOS tube 111 is turned off.

[0051] According to one embodiment of the present invention, Figure 3 As shown, the LC oscillation circuit 105 includes a first LC oscillation circuit unit and a second LC oscillation circuit unit. The input end of the first LC oscillation circuit unit is used to input a DC source signal. The output end of the first LC oscillation circuit is respectively connected to the input end of the second LC oscillation circuit and the second end of the MOS tube 111. The third end of the MOS tube 111 is grounded. The output end of the second LC oscillation circuit is connected to the corresponding array element of the phased array ultrasonic transducer 106.

[0052] According to one embodiment of the present invention, Figure 3As shown, the first LC oscillation circuit unit includes: a Wheatstone bridge 118, a seventh capacitor C7, an eighth capacitor C8, a ninth capacitor C9, a seventh resistor R7, a first inductor L1, and a first diode D1. The first end 1 and the second end 2 of the Wheatstone bridge 118 are respectively connected to a DC source signal, the fourth end 4 of the Wheatstone bridge 118 is grounded, the third end 3 of the Wheatstone bridge 118 is respectively connected to one end of the seventh capacitor C7 and one end of the seventh resistor R7, the other end of the seventh capacitor C7 is grounded, the other end of the seventh resistor R7 is respectively connected to a fourth power supply VCC and a cathode of the first diode D1, the anode of the first diode D1 is connected to the first end 1 of the first inductor L1, the second end 2 of the first inductor L1 is grounded, the third end 3 of the first inductor L1 is respectively connected to one end of the eighth capacitor C8 and one end of the seventh capacitor C7, the other end of the eighth capacitor C8 is grounded, the fourth end 4 of the first inductor L4 is respectively connected to one end of the ninth capacitor C9 and the second LC oscillation circuit unit, and the other end of the ninth capacitor C9 is grounded.

[0053] According to one embodiment of the present invention, Figure 3 As shown, the second LC oscillation circuit unit includes: a tenth capacitor C10, an eleventh capacitor C11, a twelfth capacitor C12, a thirteenth capacitor C13, a fourteenth capacitor C14, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, a second inductor L2, and a second diode D2, one end of the tenth capacitor C10 is connected to the other end of the ninth capacitor C9, the other end of the tenth capacitor C10 is connected to the first end 1 of the second inductor L2, the second end 2 of the second inductor L2 is connected to the anode of the second diode D2, the cathode of the second diode D2 is connected to one end of the eighth resistor R8, the other end of the eighth resistor R8 is connected to one end in parallel of the ninth resistor R9 and the eleventh capacitor C11, the ninth resistor R9 and the eleventh resistor R10 are connected to the second inductor L2, and the cathode of the second diode D2 is connected to one end of the eighth resistor R8. The other end of the capacitor C11 in parallel is connected to the third end 3 of the second inductor L2, the fourth end 4 of the second inductor L2 is respectively connected to one end of the twelfth capacitor C12, the other end of the twelfth capacitor C12 is connected to one end of the thirteenth capacitor C13, the other end of the twelfth capacitor C12 is grounded, the other end of the thirteenth capacitor C13 is connected to one end of the tenth resistor R10, one end of the tenth resistor R10 is grounded, the other end of the tenth resistor R10 is connected to the other end of the parallel connection of the ninth resistor R9 and the eleventh capacitor C11, the fourth end 4 of the second inductor L2 is also connected to one end of the fourteenth capacitor C14, the other end of the fourteenth capacitor C14 is grounded, and one end of the fourteenth capacitor C14 is connected to the phased array ultrasonic transducer 106.

[0054] The MOS transistor 111 is turned on at a high level, so that the potential of the connection point v between the first LC oscillating circuit unit and the second LC oscillating circuit unit is zero. At this time, currents exist in both the first inductor L1 and the second inductor L2, and their values ​​are equal to the current passing through the MOS transistor 111, which protects the MOS transistor 111 from being burned out. When the MOS transistor 111 is turned on, the LC oscillating circuit 105 is equivalent to parallel resonance.

[0055] When the MOS transistor 111 is disconnected at a low level, the potential of the connection point v between the first LC oscillating circuit unit and the second LC oscillating circuit unit is not zero. When the MOS transistor 111 is disconnected, the LC oscillating circuit 105 is equivalent to series resonance, thereby outputting a high-amplitude sine wave.

[0056] The detailed derivation process is as follows:

[0057] When the MOS tube is turned on, v is zero, and the first LC oscillating circuit unit and the second LC oscillating circuit unit are connected in parallel. That is, That is,

[0058] When the MOS tube is disconnected, the first LC oscillation circuit unit and the second LC oscillation circuit unit are connected in series.

[0059] Among them, according to the volt-second balance condition, ΔI1=ΔI2=ΔI.

[0060] because, Also because so,

[0061] Furthermore, t on =t off , and because t on +t off =T, so t on =t off =ΔT, so, Also because Then v = 2v in .

[0062] Then, when the MOS tube is disconnected, the original 2V in The amplitude input increases the amplitude of the final output sine wave, which is approximately ±200V.

[0063] Specifically, if Figure 3As shown, the first end 1 and the second end 2 of the signal output device 119 output a DC source signal, the third end 3 and the fourth end 4 output a PWM wave, and the fifth end 5 and the sixth end 6 are suspended, that is, no signal is connected. When the first end 1 of the optical coupler 113 inputs a high level and the second end 2 inputs a low level, the optical coupler 113 is turned on, the fifth end 5 of the optical coupler outputs a high level, the first input end 1 and the second input end 2 of the first NAND gate 114 are both high levels, the output end 3 outputs a low level, and the first input end 1 of the second NAND gate 115 is a low level. At this time, regardless of whether the output end 3 of the fourth NAND gate 117 in the crystal oscillator unit 109 outputs a high level or a low level, the output end 3 of the second NAND gate 115 is a high level, the first input end 1 and the second input end 2 of the third NAND gate are both high levels, and the output end 3 is a low level. At this time, the second switch tube Q2 is turned on, the first switch tube Q1 is turned off, the MOS tube 111 is turned off, and the first LC oscillation circuit unit and the second LC oscillation circuit unit are connected in series.

[0064] When the first terminal 1 of the optocoupler 113 inputs a low level and the second terminal 2 inputs a high level, the optocoupler 113 is disconnected, and the fifth terminal 5 of the optocoupler outputs a low level. The first input terminal 1 and the second input terminal 2 of the first NAND gate 114 are both low levels, and the output terminal 3 outputs a high level. The first input terminal 1 of the second NAND gate 115 is a high level. At this time, when the output terminal 3 of the fourth NAND gate 117 in the crystal oscillator unit 109 outputs a high level, the output terminal 3 of the second NAND gate 115 is a low level, the first input terminal 1 and the second input terminal 2 of the third NAND gate are both low levels, and the output terminal 3 is a high level. At this time, the second switch tube Q2 is disconnected, the first switch tube Q1 is turned on, the MOS tube 111 is turned on, and the first LC oscillation circuit unit and the second LC oscillation circuit unit are connected in parallel. When the output terminal 3 of the fourth NAND gate 117 in the crystal oscillator unit 109 outputs a low level, the output terminal 3 of the second NAND gate 115 is a high level, the first input terminal 1 and the second input terminal 2 of the third NAND gate are both high levels, and the output terminal 3 is a low level, at this time, the second switch tube Q2 is turned on, the first switch tube Q1 is turned off, the MOS tube 111 is turned off, and the first LC oscillation circuit unit and the second LC oscillation circuit unit are connected in series.

[0065] In general, when the optocoupler 113 is turned on, regardless of whether the crystal oscillator unit 109 outputs a baseband signal, the MOS tube 111 is in an off state; when the optocoupler 113 is turned off, the MOS tube 111 is in an on state only when the crystal oscillator unit 109 outputs a baseband signal, and at other times, the MOS tube 111 is in an off state. Therefore, the on and off of the optocoupler 113 and the baseband signal output by the crystal oscillator unit 109 determine whether the MOS tube 111 is turned on. The optocoupler 113 acts as a switch in the circuit system. When the optocoupler 113 is turned on, the LC oscillation circuit 105 does not receive the baseband signal, and thus does not perform sinusoidal oscillation. In other words, the entire system is in an off state. When the optocoupler 113 is turned off, when the LC oscillation circuit 105 receives the baseband signal, that is, when the MOS tube is turned on, it does not perform sinusoidal oscillation. When the LC oscillation circuit 105 receives the baseband signal, that is, when the MOS tube is turned on and off, it performs sinusoidal oscillation. That is to say, the PWM wave output by the FPGA focus delay module 102 only controls the on and off of the optical coupler 113 and has no other functions.

[0066] Since the input signal of the LC oscillation circuit 105 is a DC source signal, the amplitude is higher than the amplitude of the square wave signal in the prior art. The traditional phased array ultrasonic transducer can provide high-frequency sine excitation with an amplitude of ±20 to ±50V and square wave excitation of ±100V, while the sine wave excited by the present system is a high-frequency sine wave of ±200V, and the power is 16 times that of the traditional excitation source.

[0067] It should be noted that the baseband control circuit 104 and the LC oscillation circuit 105 also include a voltage stabilizing circuit unit 120, such as Figure 3 As shown, the voltage stabilizing circuit unit 120 includes a fifteenth capacitor C15 , a sixteenth capacitor C16 , a seventeenth capacitor C17 and a voltage stabilizer 121 .

[0068] According to one embodiment of the present invention, Figure 4 As shown, the phased array ultrasonic transducer excitation system 100 for increasing the amplitude also includes:

[0069] The hardware delay compensation module 120 has an input end connected to the output ends of the plurality of LC oscillation circuits 105 , and an output end connected to the phased array ultrasonic transducer 106 .

[0070] Since various hardware in the circuit will also cause delays to the signal, the signal can be further focused after the sine wave is oscillated through the hardware delay compensation module 120, so that each array element of the phased array ultrasonic transducer 106 receives the sine signal at the same time.

[0071] The phased array ultrasonic transducer excitation system 100 for increasing the amplitude proposed in the embodiment of the present invention can increase the intensity of the focused acoustic field used by TMAS, thereby increasing the TMAS electric field. The phased array ultrasonic transducer excitation system 100 for increasing the amplitude can also be widely used in all ultrasonic phased array transducers with a specific frequency, and can provide a higher amplitude to excite the ultrasonic transducer to provide a higher sound intensity. That is, when the fundamental frequency of the crystal oscillator unit changes, sine waves of different frequencies can be oscillated.

[0072] In addition, the phased array ultrasonic transducer excitation system 100 for increasing the amplitude proposed in the embodiment of the present invention is different from the traditional phased array ultrasonic transducer excitation system. The phased array ultrasonic transducer excitation system 100 for increasing the amplitude combines the excitation signal generating device and the excitation signal amplifying device into one, does not perform timing signal amplification, directly transmits PWM waves by FPGA to perform multi-channel pulse focusing control, and uses a crystal oscillator to fix the frequency. Different models of crystal oscillators can provide sinusoidal pulses of different frequencies, and the high-voltage and high-frequency sinusoidal circuit directly acts on both ends of the phased array ultrasonic transducer to perform transducer focusing excitation.

[0073] Furthermore, the phased array ultrasonic transducer excitation system 100 for increasing the amplitude proposed in the embodiment of the present invention has the following advantages: 1) A crystal oscillator is used to determine the sinusoidal frequency of the excitation pulse, which has the advantages of stability and good anti-interference performance. Since a logic gate is used to control the crystal oscillator, a variety of crystal oscillator switches can be used to connect to make the system frequency adjustable without changing the circuit, thus overcoming the disadvantage of the fixed frequency of the crystal oscillator circuit. 2) The traditional phased array ultrasonic transducer can provide a high-frequency sinusoidal excitation with an amplitude of ±20 to ±50V and a square wave excitation of ±100V. This module uses an LC oscillation circuit to provide a maximum of ±200V high-frequency sinusoidal excitation, which is 16 times the power of the traditional excitation source, and the sinusoidal excitation has zero high-frequency component compared to the square wave excitation, which can reduce load heating and piezoelectric ceramic vibration loss, and can significantly improve the service life of the ultrasonic phased array transducer. 3) The traditional excitation system transmits a sine pulse with timing information, while this excitation system uses FPGA to transmit PWM waves to control the emission and termination of the sine wave. Using the NAND logic gate, the high level of the PWM wave controls the emission of the sine signal, and the low level of the PWM wave controls the end of the sine signal, making the modulation of the sine pulse programming simpler and more convenient in actual use. 4) This system combines the excitation signal generating device and the excitation signal amplifying device into one, and uses a crystal oscillator to provide the circuit reference frequency, and LC resonance modulates the sine. Compared with other excitation systems, it is simpler to assemble and has a lower weight, and can be used to expand the focusing control of phased array transducers with more channels.

[0074] In general, (1) this system uses an LC oscillation circuit to oscillate a sinusoidal pulse for pulse excitation, while other systems usually use square wave direct excitation or SPWM, and three-state wave simulated sinusoidal excitation. (2) this system only needs to input a PWM command signal and a primary DC power supply, and can directly oscillate a sine wave through an analog circuit. Traditional other systems require two parts: editing the sine wave and amplifying the sine wave. This system is more convenient and faster. (3) this system does not need to build a power amplifier, and the output amplitude does not depend on the performance of MOSFET and high-frequency transformer. Compared with other systems, it can provide a larger voltage amplitude.

[0075] That is to say, this system can set the transducer related parameters and the duty cycle of the expected transmitted sinusoidal modulated pulse through PC programming, and directly convert them into sinusoidal by the hardware analog circuit by transmitting PWM waves, so as to perform precise sinusoidal focused excitation on the ultrasonic phased array transducer. This method has a higher output sinusoidal amplitude, and the accuracy of the sinusoidal waveform is determined by the LC oscillation circuit. The programming is simple and convenient, and only needs to transmit a high ground level to control the logic 1 / 0.

[0076] In summary, according to an embodiment of the present invention, a phased array ultrasonic transducer excitation system for increasing amplitude is proposed, comprising: a PC, an FPGA focus delay module, an I / O channel expansion module, a plurality of baseband control circuits and a plurality of LC oscillation circuits, wherein the baseband control circuit corresponds to the LC oscillation circuit one by one; the PC is used to provide focus excitation parameters of each channel of the phased array ultrasonic transducer, the FPGA focus delay module is used to calculate the focus delay data of each channel according to the focus excitation parameters of each channel, and output a PWM wave carrying the focus delay data corresponding to each channel in combination with the focus delay data of each channel, the PWM wave carrying the focus delay data corresponding to each channel is input into the corresponding baseband control circuit through the I / O channel expansion module, and each LC oscillation circuit oscillates the DC source signal into a sinusoidal wave signal according to the baseband signal output by the baseband control circuit and outputs it to the corresponding channel of the phased array ultrasonic transducer. By exciting a high-amplitude sinusoidal wave through the excitation system, it has zero high-frequency components, can reduce load heating and piezoelectric ceramic vibration loss, and can significantly improve the service life of the phased array ultrasonic transducer.

[0077] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A phased array ultrasonic transducer excitation system for increasing amplitude, characterized in that: include: A PC, an FPGA focus delay module, an I / O channel expansion module, a plurality of baseband control circuits and a plurality of LC oscillation circuits, wherein the baseband control circuits correspond to the LC oscillation circuits one by one; The PC is used to provide focus excitation parameters of each channel of the phased array ultrasonic transducer, the FPGA focus delay module is used to calculate the focus delay data of each channel according to the focus excitation parameters of each channel, and output a PWM wave carrying the focus delay data corresponding to each channel in combination with the focus delay data of each channel, the PWM wave carrying the focus delay data corresponding to each channel is input into the corresponding baseband control circuit through the I / O channel expansion module, and each of the LC oscillation circuits oscillates the DC source signal into a sine wave signal according to the baseband signal output by the baseband control circuit and outputs it to the corresponding channel of the phased array ultrasonic transducer; The baseband control circuit comprises: An optocoupler circuit unit, a NAND gate circuit unit, a crystal oscillator unit, a MOS tube control unit and a MOS tube, wherein the input end of the optocoupler circuit unit is connected to the I / O channel expansion module, the output end of the optocoupler circuit unit is connected to the input end of the NAND gate circuit unit, the output end of the crystal oscillator unit is connected to the input end of the NAND gate circuit unit, the output end of the NAND gate circuit unit is connected to the MOS tube control unit, and the MOS tube is in an open state or a closed state according to the level signal output by the MOS tube control unit to provide a baseband signal for the LC oscillation circuit; The optocoupler circuit unit comprises: a first power chip, an optocoupler and a first capacitor, the first end and the second end of the optocoupler are respectively input with the PWM wave signal, the third end of the optocoupler is connected to the output end of the first power chip, the fourth end of the optocoupler is grounded, the fifth end of the optocoupler is connected to the NAND gate circuit unit, the first power chip supplies power to the optocoupler, the output end of the first power chip is also connected to one end of the first capacitor, and the other end of the first capacitor is grounded; The NAND gate circuit unit comprises: a first NAND gate, a second NAND gate, a third NAND gate and a first resistor, wherein a first input terminal of the first NAND gate is connected to one end of the first resistor, the other end of the first resistor is connected to a second power supply, a first input terminal of the first NAND gate is connected to a second input terminal, and a second input terminal of the first NAND gate is connected to a fifth end of the optical coupler; The output end of the first NAND gate is connected to the first input end of the second NAND gate, the second input end of the second NAND gate is connected to the crystal oscillator unit, the output end of the second NAND gate is respectively connected to the first input end and the second input end of the third NAND gate, and the output end of the third NAND gate is connected to the input end of the MOS tube control unit; The crystal oscillator unit includes: a fourth NAND gate, a second resistor, a third resistor, a second capacitor, a third capacitor and a fourth capacitor, one end of the second capacitor and the third capacitor are both grounded, the other end of the second capacitor is connected to one end of the fourth capacitor, the other end of the third capacitor is connected to the other end of the fourth capacitor, the other end of the fourth capacitor is also connected to one end of the second resistor, the other end of the second resistor is connected to the output end of the fourth NAND gate, one end of the fourth capacitor is also connected to the first input end and the second input end of the fourth NAND gate, one end of the third resistor is connected to the first input end and the second input end of the fourth NAND gate, the other end of the third resistor is connected to the output end of the fourth NAND gate, and the output end of the fourth NAND gate is connected to the second input end of the second NAND gate; The MOS tube control unit includes: a fourth resistor, a fifth resistor, a sixth resistor, a fifth capacitor, a sixth capacitor, a first switch tube and a second switch tube, wherein one end of the fourth resistor and the fifth capacitor connected in parallel is connected to the output end of the third NAND gate, and the other end is respectively connected to the control end of the first switch tube and the second switch tube, the source of the first switch tube is connected to the third power supply and one end of the sixth capacitor, the other end of the sixth capacitor is grounded, the drain of the first switch tube is respectively connected to the drain of the second switch tube and one end of the fifth resistor, the source of the second switch tube is grounded, the other end of the fifth resistor is respectively connected to the control end of the MOS tube and one end of the sixth resistor, and the other end of the sixth resistor is grounded.

2. The phased array ultrasonic transducer excitation system for increasing amplitude according to claim 1, characterized in that: The LC oscillation circuit includes a first LC oscillation circuit unit and a second LC oscillation circuit unit, the input end of the first LC oscillation circuit unit is used to input the DC source signal, the output end of the first LC oscillation circuit is respectively connected to the input end of the second LC oscillation circuit and the second end of the MOS tube, the third end of the MOS tube is grounded, and the output end of the second LC oscillation circuit is connected to the corresponding array element of the phased array ultrasonic transducer.

3. The phased array ultrasonic transducer excitation system for increasing amplitude according to claim 2, characterized in that: The first LC oscillation circuit unit includes: a Wheatstone bridge, a seventh capacitor, an eighth capacitor, a ninth capacitor, a seventh resistor, a first inductor, and a first diode. The first end and the second end of the Wheatstone bridge are respectively connected to the DC source signal, the fourth end of the Wheatstone bridge is grounded, the third end of the Wheatstone bridge is respectively connected to one end of the seventh capacitor and one end of the seventh resistor, the other end of the seventh capacitor is grounded, the other end of the seventh resistor is respectively connected to a fourth power supply and a cathode of a first diode, the anode of the first diode is connected to a first end of the first inductor, the second end of the first inductor is grounded, the third end of the first inductor is respectively connected to one end of the eighth capacitor and one end of the seventh capacitor, the other end of the eighth capacitor is grounded, the fourth end of the first inductor is respectively connected to one end of the ninth capacitor and the second LC oscillation circuit unit, and the other end of the ninth capacitor is grounded.

4. The phased array ultrasonic transducer excitation system for increasing amplitude according to claim 3, characterized in that: The second LC oscillation circuit unit includes: a tenth capacitor, an eleventh capacitor, a twelfth capacitor, a thirteenth capacitor, a fourteenth capacitor, an eighth resistor, a ninth resistor, a tenth resistor, a second inductor, and a second diode, one end of the tenth capacitor is connected to the other end of the ninth capacitor, the other end of the tenth capacitor is connected to the first end of the second inductor, the second end of the second inductor is connected to the anode of the second diode, the cathode of the second diode is connected to one end of the eighth resistor, the other end of the eighth resistor is connected to one end of the ninth resistor and the eleventh capacitor in parallel, and the other end of the ninth resistor and the eleventh capacitor in parallel is connected to the first end of the second inductor. The first end of the second inductor is connected to the third end of the second inductor, the fourth end of the second inductor is respectively connected to one end of the twelfth capacitor, the other end of the twelfth capacitor is connected to one end of the thirteenth capacitor, the other end of the twelfth capacitor is grounded, the other end of the thirteenth capacitor is connected to one end of the tenth resistor, one end of the tenth resistor is grounded, the other end of the tenth resistor is connected to the other end of the ninth resistor and the eleventh capacitor in parallel, the fourth end of the second inductor is also connected to one end of the fourteenth capacitor, the other end of the fourteenth capacitor is grounded, and one end of the fourteenth capacitor is connected to the phased array ultrasonic transducer.

5. The phased array ultrasonic transducer excitation system for increasing amplitude according to any one of claims 1 to 4, characterized in that: Also includes: A hardware delay compensation module, wherein the input end of the hardware delay compensation module is connected to the output ends of the plurality of LC oscillation circuits, and the output end of the hardware delay compensation module is connected to the phased array ultrasonic transducer.

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