Energy-efficient implantable transmitter for restenosis monitoring with intelligent-stents

An analog circuit forming part of an intelligent-stent system is proposed with the aim of converting pressure-related capacitance measurements into a FM signal (around 800 MHz) to be analyzed outside of the patient body. Based on the information obtained from this signal, a reliable restenosis monitoring can be carried out. An energy-saver block controls the oscillator and reduces the power consumption of the whole circuit from 547.1 µW in active state to 152.1 µW in idle state, in order to comply with energy restriction imposed by inductive coupling powering. The design is implemented in TSMC 0.18 µm CMOS technology.