Circuit techniques for effective wireless transfer of power and data to electronic implants

Novel circuit techniques and design approaches are proposed in this paper to build a controller dedicated to wireless power and data transmission systems used in the area of implantable devices such as sensors and neurostimulators. The aim of this controller is to regulate automatically the level of the power to be transferred and to modulate the carrier signals during data transmission. It includes several new integrated building blocks such as integrated pulse-width modulator (PWM), RF envelope detector, frequency-locked loop (FLL), and amplitude-shift keying (ASK) modulator and demodulator. CMOS 0.18 mu m technology is used to implement this controller that operates at 1.8V power supply and a frequency of 20 MHz. Preliminary postlayout simulation results prove that all the main blocks of the controller (the FLL, the PWM, and the ASKD) operate adequately. From simulation results, the time response of the system is estimated at 0.8 mu s. The complete controller has been recently submitted for fabrication.