Design and Simulation Model of Implantable Wireless Neural Stimulator

Implantable wireless neural stimulators have emerged as a critical technology in modern biomedical engineering due to their ability to eliminate battery dependency and repeated surgical procedures. This paper presents the detailed design and LTspice simulation of an implantable wireless neural stimulator powered using magnetic resonant inductive wireless power transfer. Remotely powered IMDs that enable safer and smaller neural interfaces are especially useful to freely moving animals and human subjects. Even more so for chronic applications, since rigid tethered electrodes suffer from micromotion, which results in tissue inflammation and scar formation around the electrodes. The simulation model is tailored for the development of neurostimulators characterized by swift settling times, intended for applications in the treatment of conditions such as Parkinson's disease, chronic pain, epilepsy, etc. The proposed system integrates a high-efficiency buck converter, Class-E inverter, four-coil resonant wireless power transfer link, Class-E rectifier, and a monostable multivibrator-based pulse generator. The system is designed to operate at 150 kHz to achieve optimal power transfer efficiency while maintaining safe operating conditions for biological tissues. Simulation results demonstrate stable voltage regulation, efficient wireless power delivery, and reliable generation of neural stimulation pulses with a pulse width of 50 ms and amplitude of 4.77 V. The results validate the feasibility of the proposed architecture for long-term implantable neural stimulation applications.