The hit that caused Charles to be checked for a concussion was one that was so hard that it knocked the decal off of his helmet (via Reddit):
Arrowhead Addict has a GIF of the hit, which looks like one of the dozens of hits we see in every football game.
We know that Charles was ultimately cleared of a concussion. I saw him in the locker room after the game and he spoke to the media as normal. Andy Reid said on Monday that Jamaal felt pretty good despite the concussion check and knee and ankle injuries.