A Wearable High-Voltage Functional Electrical Stimulator with Sub-20 ns Switching Time for Stimulation with Reduced Pain

This paper presents a wearable high-voltage functional electrical stimulation (FES) device. Compared to conventional FES devices, the proposed design aims to offer users a more comfortable therapeutic experience. This is enabled by achieving a sub- 20 ns fast switching time, activating muscles but fewer pain receptors. The FES device is equipped with a high compliance voltage up to 135 V, designed to accommodate different muscle groups and is suitable for users with varying skin conductance levels. At the core of the FES system is a switched capacitor (SC) stimulator for fast switching, and a flyback converter responsible for stepping up the battery voltage. The system incorporates only off-the-shelf components, which significantly lowers the prototyping cost. The proposed design methods are applicable across a wide range of applications in neural rehabilitation.