The cochlear implant is the most successful neural implant that has been commercialized ever since. Although one of the most limiting challenges in design of neural implants is efficient data and power transmission, the research trend has been mostly on improvement of signal processing algorithms and use of advanced biomaterials. So there is a tremendous need in improvement of data and power transmission link of cochlear implants. The conventional method used in cochlear implants for power and data transmission is use of inductive transcutaneous power and data link. This method is based on using two loosely coupled coils that are placed in two sides of the skin and transmit data and power by electromagnetic coupling. Because of the limitation of the human body, the frequency and power of the transmitted signal should be limited to a certain range so the living tissue not be harmed. Because the practical design values are limited to frequency range of hundreds of kilo hertz to a few mega hertz and the power rang of hundreds of miliwatts to a few watts, use of conventional RF amplifiers or conventional switching amplifiers may not be efficient. So a new circuit should be designed to meet this specific frequency and power range requirements. The design goal is to transmit power with maximum efficiency and with minimum sensitivity to the non-idealities of the link and simultaneously transmit data with maximum bandwidth and minimum disturbance and use minimum number of extra circuits in minimum of size. This thesis focuses on design of data and power transmission circuits of the transcutaneous link in two sections. In the first section, an introduction to the general structure of cochlear implants and the transcutaneous power and data transmission link is discussed. Then the available circuits that can be use for data and power transmission in the inductive link are briefly discussed and finally the design of the justify; MARGIN: 0cm 0cm 10pt; unicode-bidi: embed; DIRECTION: ltr" In the second section, available options that can be used for receiving the power and data and the evolution path of internal power regulation circuits in cochlear implants are introduced briefly and based of one of recent high-efficiency switching voltage regulators used in cochlear implants, a new converter is proposed. The proposed converter has remarkable advantage over the conventional circuits in term of efficiency, voltage gain and converter size. In end of this section practical test results of a lab prototype of the proposed converter is presented. Keywords: 1- Switching power supplies, 2- Transcutaneous inductive link, 3- High frequency switching power supplies 4- High step up converters and regulators, 5- Soft switching converters, 6- Data and power transmission circuits