The former Tottenham trainee, who was on the Swans' bench for Saturday's 2-1 defeat against West Brom, could make his Addicks debut in the south London derby against Millwall on Saturday.
"He's a midfielder I've had an eye on for a while," Addicks manager Chris Powell told the club website.
"It's an area that I felt we needed someone just to come in and boost the numbers. He's got a good pedigree.
"He's a talented player, a good user of the ball and I think he will just add quality to the squad.
"I'm looking at him just to help us over the line for the rest of the season and then who knows. Maybe depending on how it goes he may be someone I look at for the future."