Analysis and Design of Four-Level Flying-Capacitor Converter in Burst Mode Operation

The design analysis and loss model of the four-level flying-capacitor converter in burst mode operation is introduced. Detailed analysis of the proposed converter including operating mode, charge balance characteristic, and loss estimation for optimum efficiency are given. One-shot injected burst mode operation is also proposed which can reduce the voltage ripple of the flying-capacitor. The proposed scheme and analysis are verified by the simulation study. The simulation results with the input voltage range of 3-5V (for Li-Ion battery), the output voltage range of 0.6V-1.2V(typical supply voltage of digital circuits), 1mA <; load current shows the verification of the full-time active balancing scheme and the ripple minimization of the proposed technique.