Amazon.com: 500Ma DC-DC Boost Converter Board Voltage Step-Up Module 3.3V, No Pins; 3.3V, for Aa, AAA Battery-Powered Devices, Breadboard, Small Power Motor, Cameras, Electric Toys : Electronics
Tiny Buck-Boost Converter for Low Current Applications | Analog Devices
Circuit enables constant-power-boost converter-Power/Smart Energy-EDN Asia