A Symmetric Modified Multilevel Ladder PMIC for Battery-Connected Applications

Abstract

This article describes a symmetric modified multilevel ladder (SMML) converter that is capable of directly converting down from Li-ion battery voltage ranges to system-on-chip (SoC)-compatible voltage ranges while using low-voltage power MOSFETs in the power stage. Compared to conventional flying-capacitor multilevel converters, the SMML converter features reduced conduction losses, naturally balanced flying capacitors, and internal generation of all the supplies required for drivers and level shifters. A prototype shows that the converter achieves a peak efficiency of 90% and a peak power density of 0.52 W/mm2 while providing up to 16.7 $\times $ conversion ratios at still acceptable efficiencies.