A 10-MHz Three-Level Buck Converter with Dual-Loop Time-Based Control and Flying Capacitor Voltage-Balance for Fast DVS

High efficiency, small footprint and fast dynamic response are the key parameters of power management integrated circuits for portable applications. In this context, the three-level buck converter (TLBC) emerges as a practical solution, as it doubles the switching frequency and reduces the voltage swing at the switching node, compared to a conventional buck converter. As results, a small volume inductor can be employed, and high bandwidth can be achieved without compromising the converter's efficiency. However, precise regulation of the flying capacitor voltage at half the input supply is mandatory to ensure the reliable operation of the converter. This paper presents a dual-loop time-based control for a 10-MHz 2.8~3.6-V input and 0.6~ 1.2- V output TLBC. The proposed time-based controller merges the flying capacitor and the output voltage regulation in a single structure, thus minimizing the area occupation. The controller was designed in a 150-nm BCD technology. Simulations in SIMetrixlSIMPLIS demonstrates the efficacy and the robustness of the proposed control.