A Noninverting Buck–Boost Converter With State-Based Current Control for Li-ion Battery Management in Mobile Applications

In this letter, a noninverting buck–boost converter with state-based current control is proposed for Li-ion battery management. Unlike conventional multimode control in buck–boost converters, our control scheme utilizes a state controller with a single-level error current and a state checking clock to define the operation mode at every cycle. The state-based buck–boost converter enables seamless mode transition and stable output regulation with fixed interleaving patterns even when input and output voltages are similar, ensuring robust mode change with inherent hysteresis. The prototype IC was fabricated in a 0.18-μm BCD process and achieved 90.9% efficiency with 1.1-A maximum load current capability at 1-MHz switching frequency.