An ultra-low input voltage power management circuit for indoor micro-light energy harvesting system

Power management technology for energy harvesting offers big challenge on energy storage and management because the delivered voltage is much lower than the threshold voltage of standard electronic devices under very low indoor light intensity, so it is often unsuitable for standard power management chips. In this paper, we present a special ultra-low start-up voltage power management circuit that allows it to boost input voltage as low as 40mV to provide output voltage (4.1V) for wireless humiture sensor node. The measured prototype can successfully drive the wireless sensor load when the humiture sensor node transmits signal.