Integrated inductive power and data recovery front-end dedicated to implantable devices

For most implantable biomedical devices, inductive power is an important alternative to the limited lifetime batteries. In case of a near-field inductive link, the induced voltage is usually much larger than the compliance of low-voltage integrated circuit (IC) technologies. Most power recovery approaches limit the voltage with inefficient shunt regulation, or voltage clipping. In this paper, a step-down approach, where the induced voltage is not limited, is adopted to integrate this front-end using a high-voltage (HV) CMOS technology. The proposed fully-integrated inductive power and data recovery front-end is a first version composed of two separate ICs of 9mm2 each for validation purposes. The first IC integrates in particular two different rectifiers, a voltage doubler and a bridge rectifier. Simulation results show that both rectifier designs achieve more than 90% power efficiency at 1mA load, and provide more than 14V output at 3mA load with a limited available inductive power of 50mW only.