Transfert d'energie et transmission bidirectionnelle de donnees par couplage inductif pour des systemes electroniques implantables (French text)

This thesis deals with the transfer and data transmission systems (PTDT) that are dedicated to implantable electronic systems (IES) used in the bioengineering area. Among the existing the PTDT systems, the electromagnetic ones, which carry the power transfer and the data transfer wirelessly by means of radio frequency (RF) waves, are currently the most used. These systems are based essentially on the use of an inductively coupled link that is driven by a high efficiency power amplifier (PA). The coupled link comprises two resonant tuned circuits: a primary one (part of an external command unit) and a secondary one (in an implant).; In this context, we propose a new integrated controller dedicated to control the PA output of an electromagnetic PTDT system. This control is aimed to reduce the PTDT system power consumption by operating the PA and the inductive link in their optimal conditions. The controller enables also the system to carry simultaneously power transfer and data transmission between the external command unit and the implant. The targeted electromagnetic PTDT is composed, in this case, of a Class D switching PA and an inductive link with a gain characterized by a small sensitivity to antennas misalignments.; The controller establishes a feedback from the primary circuit of the inductive link to the PA control input. The role of this feedback is to automatically regulate the level of the PA output voltage and eventually the required power to be transmitted to the implant. This regulation is accomplished by modulating the duty-cycle of the PA amplifier input signal, which is derived from the voltage of the primary circuit of the inductive link. This kind of duty-cycle modulation has the advantage of allowing the PA and the inductive link to operate in their optimal conditions. Firstly, it allows the PA to operate with a fixed switching frequency (fsw), and secondly, it allows the primary circuit to be tuned to a resonance frequency ( f01) equal to the frequency fsw.; The architecture of the proposed controller comprises three new main basic blocks, which are integrated in CMOS technology: a pulse-width modulator (PWM), a frequency-locked loop (FLL), and an ASK demodulator (ASKD). The role of the new PWM is to generate the PA control signal with a duty-cycle dynamic range of 0% to 50%. The architecture of this PWM is based on voltage-controlled delay lines and logic gates, which process the rising and the falling edges of the delay lines output voltages. The FLL is used to locally generate the controller input signal, which is a square waveform of a frequency equal to 20 MHz. The main basic element of this FLL is a new frequency-to-voltage converter (FVC), which is based on switched capacitor principle. The ASKD is based on current mode techniques and it is intended to demodulate signals, which are transmitted from the implant to the external command unit. The demodulator receives an input current with an amplitude that varies between two allowable levels (minimum and maximum) and generates a logic voltage at the output. The proposed ASKD is capable to demodulate input currents with very small difference between their minimum and maximum levels.