title: Transcutaneous transmission of digital data and energy in a cochlear prosthesis system.
abstract: This paper describes the inductive power and data link employed in the CAP Cochlear Prosthesis System (CAP stands for Combined Analog and Pulsative Stimulation Strategy). The inductive link consisting of a parallel-tuned receiver resonant circuit weakly coupled to a series-tuned transmitter resonant circuit, is driven by a self-oscillating class-E-tuned power amplifier. The class-E concept allows coupling-insensitive high-efficiency transcutaneous transmission of power. In the CAP implant, variations of the coil distance within a range of 0 to 9 mm result in changes of the implant supply voltage which are lower than 10%. Within this coil distance range, the mean overall efficiency is 49%. In view of the excellent switching properties of the class-E tuned power oscillator, a practical scheme for data transmission is ASK (Amplitude Shift Keying). To ensure constant energy flow and easy synchronization of the bitstream in the implant, a self-clocking bit format is employed.
authors.affiliation: Institute of Experimental Physics, University of Innsbruck, Austria.
authors.forename: M C
authors.initials: MC
authors.lastname: Zierhofer
authors.forename: E S
authors.initials: ES
authors.lastname: Hochmair
mesh_terms: D003054:Cochlear Implants; D011211:Electric Power Supplies; D004582:Electronics, Medical