Implanted medical devices (IMDs) are developed to monitor and record biological data from the units implanted inside the body or brain and send it to an external unit. The need for IMDs has considerably increased in recent years [1, 2] to be used for diagnostic purposes. The applications of these implantable biomedical devices include cardioverter defibrillators, cochlear implants, and deep brain stimulators. Wirelessly powered implants are a subset of IMDs that employ wireless power transmission techniques to avoid using batteries or wired powering. This method enables the design of compact and long-lasting IMDs for biomedical applications. In neural applications, IMDs are used for neural recording and brain stimulation. For instance, brain implants are utilized for Parkinson’s disease and epilepsy, by providing targeted open- or closed-loop stimulation to certain areas of the brain [2–4]. Ultrasonic, capacitive, optical, radio frequency (RF), and inductive links are the most commonly used platforms employed as a wireless power transmission technique. Inductive power transfer (IPT) is widely developed in IMDs because it is robust, straightforward, and safe. It also enables simultaneous wireless power and data communication. This book presents an implantable system that employs inductive links and CMOS electronics to develop a fully implantable wirelessly powered closed-loop multisite implant.