An Efficient Switched-Capacitor DC-DC Buck Converter for Self-Powered Wearable Electronics

This paper introduces an efficient reconfigurable, multiple voltage gain switched-capacitor dc-dc buck converter as part of a power management unit for wearable electronics. The proposed switched-capacitor converter has an input voltage of 0.6 V to 1.2 V generated from an energy harvesting source. The switched-capacitor converter utilizes pulse frequency modulation to generate multiple regulated output voltage levels, namely 1 V, 0.8 V, and 0.6 V based on two reconfigurable bits over a wide range of load currents from 10 μA to 800 μA. The switched-capacitor converter is designed and fabricated in 65-nm low-power CMOS technology and occupies an area of 0.493 mm². The design utilizes a stack of MIM and MOS capacitances to optimize the circuit area and efficiency. The measured peak efficiency is 80% at a load current of 800 μA and regulated load voltage of 1 V.