I'm not sure where I got this from, but I believe I may have gotten a TI wall adapter to a usb output for the CE when I bought it. It says input is (not surprisingly) 100-240v, and output is 5v. Hopefully that helps, unless you already knew that. Good thing that I just happened to test it with 5v initially instead of anything higher.
I was under the assumption that 5v was just the standard output for wall chargers to a device like a phone, calculator, controller, etc.