The two clubs have agreed to extend Edwards' original one-month loan, which expired after last Saturday's match against Weston-super-Mare.
The young Addicks professional, 20, has impressed Boro management and fans with his stylish and intelligent performances at left-back.
"This is an excellent move for all parties," assistant-manager Danny Bloor told his club`s official Pitchero website. "There is always a danger that loan players may come in simply to fill a shirt, but we targeted Archie as a young man who exactly meets our needs. He is a proper footballer who thinks about his game and he has slotted perfectly into the squad, popular with his teammates and with the supporters.
"Boro can give Archie valuable experience in a highly competitive league, and everyone will benefit. We are staying in close touch with his parent club to give them feedback, and we are really grateful to Charlton Athletic for their help and co-operation. They are a super club and we value our link with them".