Switched-capacitor voltage buck converter with variable step-down and switching frequency controllers for low-power and high-efficiency IoT devices

This paper proposes a switched-capacitor voltage buck converter (SC-VBC) with variable step-down controller (VSC) and switching frequency controller (SFC). The VSC and SFC change the step-down ratio and switching frequency of the SC-VBC in accordance with the input voltage and load current, respectively, enabling the converter to operate efficiently with a wide-ranging input voltage and load current. Measurements of a prototype chip demonstrated that our SC-VBC achieved a wide input voltage range and high efficiency of 1.3-2.6 V and 69%, respectively.