The minimum raise in any no limit or pot limit game (unless there's a house rule to the contrary, or you're playing Poker Night at the Inventory) is always the size of the previous bet or raise.
If the blinds are 50/100 and someone raises to 300 total they've raised by 200. 200 becomes the new minimum raise, so anyone wanting to raise after that has to make it at least 500 total.
To answer the question, no you can't raise by 100.
Pre-flop you can.
You can... what? Raise by just the amount of the big blind?
Sorry, you can't. Not unless there's some whacky house rule in play in any case.
Roberts Rules, General Poker Rules, Betting and Raising, Rule 6:
6. Any wager not all-in must be at least the size of the previous bet or raise in that round.