Ultra-low Power Autonomous Power Management System with Effective Impedance Matching for RF Energy Harvesting

This paper presents an autonomous and highly efficient power management system for RF energy harvesting. The presented circuit contains a start-up resonant converter which guaranties self-starting from a low voltage (from 200mV) and low power (from 3µW) source. During the steady-state, an ultra-low power (from 2µW) Flyback converter operating in discontinuous conduction mode is used to extract the maximum available power from the source by static impedance matching. Experimental tests demonstrate excellent performances. In fact, less than 0.1% of the source power is wasted in impedance mismatch between the source and the converter for the all input power range (2-400µW). The global Flyback converter efficiency is more than 50% @ 10muW and reaches 84% @ 370µW. Further, the low input voltage is stepped-up to over 1 Volt level allowing to power wirelessly low power electronics.