Single-Inductor Multi-Output (SIMO) DC-DC Converters With High Light-Load Efficiency and Minimized Cross-Regulation for Portable Devices

A load-dependant peak-current control single-inductor multiple-output (SIMO) DC-DC converter with hysteresis mode is proposed. It includes multiple buck and boost output voltages. Owing to the adaptive adjustment of the load-dependant peak-current control technique and the hysteresis mode, the cross-regulation can be minimized. Furthermore, a new delta-voltage generator can automatically switch the operating mode from pulse width modulation (PWM) mode to hysteresis mode, thereby avoiding inductor current accumulation when the total power of the buck output terminals is larger than that of the boost output terminals. The proposed SIMO DGDC converter was fabricated in TSMC 0.25 mu m 2P5M technology. The experimental results show high conversion efficiency at light loads and small cross-regulation within 0.35%. The power conversion efficiency varies from 80% at light loads to 93% at heavy loads.