A High Energy-Efficiency, Biphasic Exponential Current Stimulator with Loading Adaptability

• Main Authors: Chang, E Yuan, 張峨源
• Other Authors: Tang, Kea Tiong
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/6t9upf

碩士 === 國立清華大學 === 電機工程學系 === 105 === With the development of technology, Bio-medical Electrics has drawn more attention then before. Researches had shown that Functional electrical stimulation(FES) can be used to cure or replace function loss of human body and can even treat some neuron-related diseases. And thanks to the improvement of semi-conductor technology, these bio-medical devices can be integrated into small implant devices, which can replace damaged function on human body in daily life or detect and cure neuron-related problems whenever necessary. In recent years, many research groups has started to compare conventional rectangular stimuli with non-rectangular ones, and most groups has mentioned or concluded the high energy-efficiency of exponentially deceasing current stimuli. A high energy-efficiency current stimulator that can be applied to deep brain stimulation(DBS) has been proposed in this study. A maximum 300uA output stimulation can be generated to electrode of 20kohm equivalent impedance with 1V supply voltage. In order to reduce energy consumption while delivering stimulation, exponential current pulses are used due to their higher energy-efficiency when inducing action potential on tissue than conventional rectangular pulses. However, conventional exponential stimulators use a fixed high voltage source to drive the output stimulation path, this causes energy waste while exponential stimulation is not at its peak current.Therefore, a technique is proposed to make the output high voltage tracing the output stimulation current to reach high energy-efficiency. A high voltage tolerant switch array is also proposed to sustain the mentioned varying high voltage. The proposed work is simulated and fabricated using standard TSMC 0.18 um process and the circuit is designed with consideration of high voltage issue on transistors. The second proposed design is measured to have 40\% of energy consumption reduction and can generate a full biphasic exponential pulse.