Some devices don't really operate this way; some of them just try to keep pulling current until they either see voltage start dropping significantly, or they me

Some devices don't really operate this way; some of them just try to keep pulling current until they either see voltage start dropping significantly, or they meet the amount of current they need. Also, you can just put the 'correct' data connections on the phone side (keeping data disconnected on the charger side) and pull up to 5V-3A, no problem assuming the charger can handle it.