The LTC3106 is a highly integrated, 1.6μA quiescent current 300mV startup buck-boost DC/DC converter with PowerPath management, optimized for multisource, low power systems. The LTC3106 is ideal for powering low power wireless sensors from rechargeable or primary batteries supplemented by energy harvesting. If the primary power source is unavailable, the LTC3106 seamlessly switches to the backup power source. The LTC3106 is compatible with either rechargeable or primary cell batteries and can trickle charge a backup battery whenever there is an energy surplus available.The LTC3106 provides 300mA steady state and 650mA peak load current at up to 92% efficiency.
LTC3106 – 300mA Low Voltage Buck-Boost Converter – [Link]