Abstract
In recent years, electrical stimulation has been an attractive alternative for treating several neural disorders. The delivery of electrical stimulation can be controlled by either an open-loop or a closed-loop manner. Currently, most commercial systems adopt the open-loop approach to control neural stimulation, but open-loop control has been found to become less or even adverse effective in the long term. In addition, a fully implantable, closed-loop system is desirable in most applications, so as to treat or to monitor a disease for a long term with minimum risk of postoperative infection. Therefore, this chapter first introduces the advantages of closed-loop control over open-loop control. The design considerations of a fully implantable, closed-loop systems are then described and compared for different applications. As the closed-loop control can be achieved by either an embedded or external microprocessor, the advantages of different architecture are further discussed. Finally, two examples are introduced to exemplify different design requirements and considerations.