A Switched-Capacitor DC-DC Converter with Conversion Ratio Controller for Wide Output Power Range
The DC-DC converter is essential for all modern SoC (System on Chip) to provide proper supply voltage for each system block from the global supply voltage or the energy extracted by the energy harvesting system. Among them, especially IoT (Internet of Things) systems, which are increasing in demand, require DC-DC converters that occupy a small area and cover low-power area. However, the switched-capacitor DC-DC converter has a disadvantage of having a narrow output power range compared to inductor-based DC-DC converters. Therefore, the range of the output load current is limited, which may be a problem in some applications such as light sources driving DC-DC converter. In this paper, we focus on the technique of extending the output power range of the switched-capacitor DC-DC converter. The problems and limitations of the conventional structure were analyzed and based on this, an idea to expand the output power range of the switched-capacitor DC-DC converter was proposed. To prove the effectiveness of the proposed technique, a switched-capacitor DC-DC converter is designed and verified with 65nm CMOS process. Various simulations under different conditions were performed, and as a result, wide output load current range of 1 to 20 mA and good power conversion efficiency of up to 80.6% at 1mA output load current are achieved.