A Novel Single-Inductor Dual-Input Dual-Output DC–DC Converter With PWM Control for Solar Energy Harvesting System

A novel single-inductor dual-input dual-output dc-dc converter with pulse width modulation control is proposed for a solar energy harvesting system. The first input of the converter is from photovoltaic (PV) cells and the second input is a rechargeable battery. Apart from the conventional role of providing a regulated output voltage to power the loading circuits, the converter also clamps the PV cells' voltage to the maximum power point value to maximize efficiency. When the PV cells harvest more power than the load, the surplus energy is used to charge the rechargeable battery. When the PV cells cannot harvest sufficient power, the converter schedules the PV cells and the battery to power the load together. A test chip was fabricated using a 0.35-μm CMOS process and measured to verify the operation of the proposed dc-dc converter and to demonstrate the power transfer efficiency of the solar power management system.