一种用于神经刺激研究的触屏控制小型超声发生器

A touchscreen-controlled compact ultrasound generator for neuro-stimulation research

超声发生器是研究超声刺激的重要工具,但是目前并无可供选择的专用设备。目前实验室所用超声发生器通常都用多台通用仪器搭建而成,体积大,操作复杂。本文设计了一种用于神经刺激研究的小型超声发生器,用触屏作为控制界面,方便刺激参数的输入和修改;独立的E类末级功放非常小巧,可接近换能器放置,换能器的电抗参数纳入功放从而省去了匹配电路,整机体积进一步缩小。内置的现场可编程门阵列(FPGA)产生脉冲方波,经专门的驱动电路后控制E类功放中MOSFET的通断。测试表明,本文设计的超声发生器产生的波形准确,最高频率可达2 MHz。配接自制的500 kHz换能器,在30 V电源电压下输出功率6.23 W,最大声压达到168.3 kPa,并且还有可提升的空间。该发生器体积小,操作方便,电路设计简单,适用于超声神经刺激的研究。

Ultrasound generator is an important tool for studying ultrasound stimulation,but so far,there is no special equipment to choose from.The ultrasound generator currently used in laboratories is usually built with multiple generalpurpose instruments,and it is large in size and complicated in operations.Herein a compact ultrasound generator is designed for neuro-stimulation research.Using touchscreen as control interface is convenient for the input and modification of stimulation parameters.The independent class E final stage power amplifier is very small and can be placed close to the transducer,and moreover,the reactance parameters of the transducer is incorporated into the power amplifier,thus eliminating the need for matching circuits and further reducing the size of the whole machine.The pulsed square wave is generated by the built-in field programmable gate array,and the MOSFET in class E power amplifier can be controlled through a special drive circuit.The test results reveal that the ultrasound generator designed in the study can produce accurate waveforms,with a maximum frequency of 2 MHz.Equipped with a home-made 500 kHz transducer,the proposed ultrasound generator has a output power of 6.23 W and a maximum sound pressure of 168.3 kPa under 30 V power supply voltage,which can also be increased if needed.The proposed generator which is small in size,easy to operate and simple in circuit design is suitable for the research on ultrasound neuro-stimulation.