The 18-year-old has long been touted as the most talented youngster in Arsenal's academy.
After making his first-team debut last season, Patino will now get a chance to impress in the Championship.
"Charlie is a very talented boy and I'm delighted that Arsenal have trusted us to look after him and further his development," he said.
"The club has a good relationship with Arsenal from previous loan deals, as I have personally from taking players to my former clubs, with Brooke Norton-Cuffy being the most recent last season.
"Charlie is one of the best midfielders in his age group and I can't wait to start working with him."