2015 Volume 12 Issue 3 Pages 20140921
This paper presents an ultra-low-voltage high-efficiency interface circuit for energy harvesting, which features self-powered design and digital switch control. The proposed rectifier includes bridge rectifier and active diode. The former introduces self-driven switches and ultra-low voltage divider to reduce the voltage drop for wide output voltage swing. The latter adopts a common-gate comparator as switch control block to output a nearly digital signal, thereby improving dynamic response and anti-noise ability. The entire circuit exhibits good conversion efficiency and stability. Its minimum input voltage is down to 225 mV. The maximum voltage efficiency reaches to 96.3%, supplying the output current of 29 µA and the output power of 15.43 µW. The maximum power efficiency is 96.5%, providing the output current of over 16.1 µA and the output power of 5.19 µW. The whole circuit consumes the power loss of 1.42 µW.