Neil Adams says Norwich remain in the market for further additions after signing Cameron Jerome and Carlos Cuellar.
Aitor Karanka says Middlesbrough are speaking to numerous Premier League clubs - including Chelsea - about new signings.
Charles, from the famous Welsh footballing family, has put pen to paper on a contract that will keep him at the club until the summer of 2014.
"We're all really pleased for Jake, he works hard and is a great prospect," the club's Academy manager Mark Lillis told the official website.
"The opportunity for young players here is so clear and strong and parents and players can see that.
"We believe the pathways from Academy to professional and first-team level are - and will continue to be - very attractive."
Charles, who joined Town from Garforth Villa as an 11-year-old, has five Wales Under-17s caps and has scored three goals in 14 games for the club's Under-18s this season.