Wireless Power Transfer Based Implantable Neurostimulator

In this paper, we developed a miniaturized Wireless Power Transfer (WPT) based implantable stimulator that can deliver electrical energy directly to peripheral nerves using electromagnetic induction between internal and external coils. The WPT system was designed to reduce the sensitivity of alignment and increase the efficiency considering the properties of human body tissues and the implantable devices. The received electrical signals at the receiving coil are rectified by the rectifying circuit and harvested in the capacitor to turn on the pulse generating system. This creates constant monophasic rectangular pulses to stimulate nerves through the electrodes without any high specification components such as a programmable microcontroller unit (MCU). An animal study using a rat model was performed to demonstrate that the device encapsulated in a small size of 8mm × 8mm × 3mm using WPT can produce motor output by stimulating nerves.