I ported my code from an 18F452 to the 18F4550 to enable USB connectivity. Some registers had to be tweaked, but overall it wasn't too horrible. Everything is working fine, but I noticed that my heat sink is getting warm. It never got warm with the 452 in there (it's relatively big,) so I did some power draw measurements. My contraption draws 300ma or so with the 18F452 in the circuit (almost all of that is the LCD), but when I pop the 18F4550 in the circuit it draws 700ma. Why the heck would the 4550 be drawing 400ma by itself? That's way too much power! The 4550 gets to about neutral temp when touching it (not warm but not cold), and the 452 always seems cold.
What do you guys think, am I somehow sinking a bunch of current into a ground? It's the same code on both, the only thing I can think of is maybe the chip itself draws more power because of the USB support, but 400ma seems an AWFUL lot to do that. Maybe a misconfigured register setting a pin wrong? It would have to be one I'm not using since everything is working fine I/O wise..