An input-powered 1.1-μA Iq 13.56 MHz RF energy harvesting system for biomedical implantable devices

In this paper, an RF energy harvesting system is presented for biomedical implants that use 13.56 MHz RF power transfer. A predictive on/off-time technique for discontinuous conduction mode boost converters is presented to eliminate the need for a zero current detection comparator, which reduces the cost of trimming. Maximum power point tracking is employed to minimize radiated power into the human body. The harvesting system is input-powered and operates with an I_Q of 1.1 μA. The boost converter operates at 87.8% efficiency and the system can harvest energy down to an input voltage of 300 mV while charging a battery. The system is simulated and verified in a CMOS 0.25-μm process.