How to convert 5v from a usb battery pack to 2.4v~3v for use with a 2xAA powered photo camera?
Here you go, here is an easy to use package with 3-pins where you only need to add the input and output capacitors.

https://www.digikey.com/product-detail/en/microchip-technology/MCP1826S-3002E-AB/MCP1826S-3002E-AB-ND/1635993