Pololu Adjustable Step-Up Voltage Regulator U1V11A

This adjustable boost (step-up) voltage regulator generates higher output voltages (between 2 V and 5.25 V) from input voltages as low as 0.5 V, and it also automatically switches to a linear down-regulation mode when the input voltage exceeds the output. This makes it great for powering electronics projects from 1 to 3 NiMH, NiCd, or alkaline cells or from a single lithium-ion cell. Additionally, unlike most boost regulators, this unit offers a true shutdown option that turns off power to the load (with typical boost regulators, the input voltage will pass directly through to the output when they are disabled).When boosting, this module acts as a switching regulator (also called switched-mode power supplies (SMPS) or DC-to-DC converters) and has a typical efficiency between 70% to 90%. The available output current is a function of the input voltage, output voltage, and efficiency (see Typical Efficiency and Output Current section below), but the input current can typically be as high as 1.2 A.