A 17V-to-45V Input 25 μW-to-10mW Output Power, 90.2%-Peak-Efficiency SC DC-DC Converter with Recursive Output Connection for High-Voltage Energy Harvesting

A new recursive output connection switched-capacitor (SC) DC-DC converter for high-voltage harvesters is proposed in this paper. The novel architecture of the recursive output connections in each SC stage significantly reduces the conduction loss, which is the dominant loss in cascaded SC converters for low conversion ratios. Four configurable-ratio SC stages are connected through configurable series/parallel stage interconnect, which provides a wide range of harmonic conversion ratios ranging from 1/3 to 1/13. The proposed SC converter is fabricated in $0.35 \mu \mathrm{m}$ high-voltage CMOS process, achieving efficient operation over an input voltage range of 17V to 45V and wide output power range of $25 \mu \mathrm{W}$ to 10mW with peak efficiency of 90.2%. Load and line regulation is provided by a two-step controller, which periodically tracks the optimal conversion ratio and switching frequency.