Do you add Proficiency Bonus to AC?

[Varok Frenzyhea]

Since you are proficient with say, Heavy armor, would'nt u add your proficiency bonus to your total AC? Split armor (+17), Shield (+2), Proficiency Bonus (+2), coming to a total of 21.

[Forrestfire]

No. Being proficient in armor lets you cast spells in it, and being nonproficient in armor means you have disadvantage on any attack roll, ability check, or save involving Strength or Dexterity.

[MeeposFire]

Oddly I thought about making the AC bonus for monks and barbs for being unarmored rather than the secondary ability scores but I don't htink it is really worth it.

[Slipperychicken]

Only thing I know of that adds proficiency bonus to AC is the Defensive Duelist feat, but only for melee attacks, and only when you use your reaction for it.