A timer based boost converter for RF energy harvesting

The goal of this work is to minimize the required input power to achieve a net positive energy balance between incoming harvested energy and the energy costs of transforming the input signal to a useful voltage level. To reduce the energy requirements of our low voltage boost converter a low power timer is used to trigger the boosting operation. For low input power levels the act of monitoring the input voltage can use more energy than is recovered by the harvester. To extend the range of useful input powers a timer circuit is used to control how often and for how long the boost converter is activated. In this initial proof of concept, a net positive energy balance is achieved at a conducted input power level of −15 dBm at 2.45 GHz, yielding a harvester output voltage of 460mV and a boosted output voltage of 1.8V.