Research and Development of Electrical Stimulation System with Feedback Control Mechanism for Neural Prostheses

Advances in medical science makes dream come true to replace damaged organs with implantable devices. For example, Functional Electrical Stimulation (FES) has been demonstrated to be capable of generating electrical signals to stimulate muscles and neurons in the brain or peripheral nervous system (PNS) to induce action potential firing. Recent years, this approach has greatly assisted rehabilitation of damaged or degenerated organs or tissues of interest and has been widely applied to cardiac pacemaker, cochlear implant, bladder stimulator, deep brain stimulator, visual prosthesis, and pain control… etc. In general, Voltage Controlled Stimulation (VCS) and Current Controlled Stimulation (CCS) are two main types of electrical stimulation applied to implantable systems. When the impedance of electrode － tissue interface increases, stimulated current in VCS will decrease. On the other hand, a phenomenon of CCS will be discovering unequal current density on the electrode interface with high impedance between electrode and tissue of interest, which will result in broken electrode or damaged tissue. As a result, we will devote in this project the development of a closed-loop VCS architecture with adaptability, which includes a driver providing three times supply voltage at the output, a measurement circuit to monitor the impedance between electrode and tissue of interest, an analog-to-digital converter (ADC), and a digital control circuit to alter the stimulated parameters to overcome problems of impedance variations. The ultimate goal of this project is to embody the entire VCS-based stimulation system in a TSMC 0.18-μm CMOS technology as proof of concept.

Project ID:PB10308-4262
External Project ID:MOST103-2221-E182-070