block/charge, trip question

[lpbreeze]

If A1 is going down court and B1 has the spot. A1 goes by and B1 doesn't move but A1 makes contact with leg or brushes say his hip. Usually in a charge you see the defender fall down but say in this case B1 doesn't. Let play continue? Or if A1 trips and fall from the contact what would the call be? traveling if A1 keeps the ball? I saw this in a game a month ago and the offensive player fell to the floor and the coach was screaming for a tripping call but I suppose the ref thought the defender was there before.