So I've got a 3x3x3 LED cube with a quirk that I just do not understand. My cube has 2 TLC5940s controlling the columns, and 3 PNP transistors controlling the rows and works fine until I start to run out of power. Since I was powering the cube from the 5v and GND pins on the arduino this was understandable, so I go to move things to my homemade bench top supply and for some reason my SMD Arduino TOASTED =(
I know there is something seriously wrong with my circuit that isn't becoming a problem until higher current is applied...but what? I've found I can disconnect the ground to the cube and it still works (gets a little dimmer) so that means the current is going somewhere else.
The transistors are set up like:
+5V --------------- Row Anode | Pin on Arduino
My guess is current is somehow flowing through the base into the pin on the arduino, but how and and why?