A 95.3% Peak Efficiency, 135NA Quiescent Current Buck-Boost DC-DC Converter with Current-Slope-Based Mode Control

A current-slope-based mode control method is proposed for a buck-boost DC-DC converter to realize automatic mode switching between buck and boost in one switching period without additional quiescent current (IQ). Implemented in 0.18μm CMOS, the converter realizes 95.3% peak efficiency and above 90% over a load range from 15μA to 200mA. Accurate current slope measurement is achieved with initial sampling and 135nA total IQ is achieved with a zero-IQ pull-up structure in the input monitor.