A high-efficiency biotelemetry system for implanted electronic device

The development of an implanted micro-emitter having a considerable implantation depth needs a high-efficiency magnetic transcutaneous link. This paper describes a new system for the biotelemetry of internal signals. The system associates the highest performance class E power amplifier with the impedance modulation concept. The resistive load of the transmitter is influenced by the variation of the internal equivalent resistance, modulating this latter between two rails permits to modulate the amplitude of the external transmitter current and then transmitting internal digital data. Furthermore, the dependence of the modulation index on coupling factor allows to find the external coil correct position using a position feedback loop.