多通道经颅交流电刺激仪的设计

Design of Multipath Transcranial Alternating Electrical Stimulator

目的:电信号不同,对生物进行电刺激产生的生物效应也不相同。医疗领域已经研究出了许多有效成熟的电刺激治疗模式,市场上已有很多具有简单模式的电刺激仪,它们一般都只有特定的治疗模式,功能比较单一。为了满足多模式联合治疗和医学实验的需要,我们研发了一款具有多种治疗模式的交流电刺激仪。方法:该交流经颅电刺激仪选用TI的低功耗MSP430F413单片机作为主控芯片,控制以MAX038作为信号发生芯片的波形发生电路。因为MAX038能够产生0.1 Hz-20 MHz可调的正弦波、方波、三角波,可以实现两个独立控制波形的耦合输出,因此能够形成多种刺激模式。通过软件编程,使该电刺激仪具有丰富的参数设置与显示功能。结果:研制出的电刺激仪具有内置多种常用治疗模式(其中有2个为多治疗模式定时自动转换的可循环模式),利用6个中断按键作为控制键,可以方便快捷地进行模式选择和参数设置。通过配备不同的电极,可以进行电流与电场治疗模式切换:导电电极用于电流治疗,绝缘电极用于电场治疗。结论:经过多次调试和验证,该电刺激仪的输出电压Vp-p为5 V,可按需要外接医用功率放大设备进行放大,输出频率可调范围为0.1 Hz-5 MHz,调节精度为±2%,可以输出噪声较低的方波,三角波,正弦波及其调制波形,具有良好的稳定性和可靠性,同时满足国际电工委员会颁布的医疗设备安全标准,达到了最初的设计要求。

Objective： Different electrical stimulation modalities have different biological effects. Many effective, mature treat- ment modalities have been developed so far. There are many electrical stimulation devices, which have only a specific treat- ment model, on the market. This project will develop an alternating electrical stimulation device with multiple treatment mod- els to meet the needs of developing new therapeutic methods. Methods： The transcranial alternating electrical stimulator uti- lized MSP430F413 as a main controlled chip to control adjustable waveform generating circuit with MAX038 as a signal gen- erating chip. Because The output frequency of MAX038 can be controlled over a frequency range of 0.1 Hz to 20 MHz, and it can produces triangle, sawtooth, sine, square, and pulse waveforms, could generate many kinds of stimulation modes. Through software programming, the device has a rich set of parameters and display. Results： It has nine Built-in common modes of treatment, and the parameters can be set quickly and easily by six interrupt buttons. With different electrodes, electrical stimu- lation modalities can be switched over： the conductive electrodes for current treatment, and the insulated electrodes for electric field treatment. Conclusions： Though many times commissioning and validation, the output voltage of alternating electrical stimulator Vp-p is 5 V. it can be enlarged by medical amplifier, the adjustable range of the output frequency was 0.1 Hz-5MHz, the accuracy is ±2%, and might generate square wave, triangular wave, sine wave and their modulated wave with low noise. There is better stability and reliability, and it is satisfied with medical equipment safe standard IEC-601 promulgated by IEC. So it achieved the requirement.