Single-Inductor Multiple-Output (SIMO) Boost DC-DC Converter using Ripple-Based Control for Ultra-Low Power Indoor Light Energy Harvesting Applications

A Single-Inductor Multiple-Output (SIMO) Boost DC-DC Converter that operates for Ultra-Low Power (ULP) Applications is designed in 65nm TSMC technology. The converter boosts and regulates three output voltages using Ripple-Based Control of Pulse Frequency Modulation (PFM) while operating in Discontinuous Conduction Mode (DCM). To control the regulation of the output voltages, its control system follows an algorithm that is converted into digital logic circuits and helps in synchronizing the power MOS switching in the power stage. Aside from using Ripple- Based Control and DCM operation, the designed converter also uses a Strong-Arm comparator, which has no power consumption during its idle state to help ensure good power conversion efficiency of the system, making it suitable for the target application. This converter is suitable for indoor applications, for its input voltage could vary from 0.4V, for low light intensity situation, to 0.6V. With output voltages of 1.2V for analog core and two 1 V for digital cores, the converter shows excellent overall transient response and a peak power efficiency of 86% at 1mA load current.