| Summary: | 碩士 === 國立臺灣科技大學 === 電機工程系 === 107 === A current mode functional electrical stimulator(FES) with class-AB charge compensation mechanism is proposed. In the two-channel FES, a six-bit current DAC is equipped to provide the stimulation current, and the current intensity can be adjusted from 50 uA to 3 mA for animal experiments and human body use. In addition, the safety issue of the electric stimulator is also considered. Therefore, the biphasic current mode is applied to suppress the epileptic effect first by a cathodic current, and then an anodic current of the same intensity is performed for the first stage charge elimination. Besides, the generated stimulation waveform parameters can be adjusted in 12 bits to increase the application flexibility. However, due to the non-ideal effect of the process, the accumulated charge cannot be completely cancelled by the biphasic current. Therefore, an innovative class-AB based charge compensator is proposed. By the characteristics of the class AB OTA, low quiescent current and high compensation efficiency can be achieved. The two-channel FES system was combined with an analog front-end (AFE) system to develop an animal experimental platform and cooperated with the team of Professor Fang-Chia Chang of the Taiwan University Veterinary Department to conduct animal experiments to verify the safety issue and the effectiveness of the FES. In order to further increase the flexibility of the FES, a single channel FES is modularized to facilitate channel expansion. At the same time, the biphasic current architecture is improved, and the shape selection function between pulse and decaying exponential shape is added to further analysis the stimulation efficiency. This design is applied in a four-channel FES, and the performance of the chip is being measured.
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