During the last years, the high efficiency and high power density of flying-capacitor multi-level converters have been widely demonstrated. However, the adoption of this technology for low-power applications is much lower than for high-power scenarios. One of the main reasons is the complex methods used to properly balance the voltage of the flying capacitors. Aiming to overcome this problem, a novel balancing method is proposed in this work. Considering the simplicity required by low-power applications, the technique is described for the case of a flying-capacitor three-level buck converter. The key is imposing the average value on the bottom-switching-node voltage, which can be done with a simple circuit. The proposed approach is experimentally validated with a 30W, 100V to 24V flying-capacitor three-level buck converter that operates with a switching frequency of 200kHz.
