Hi,
Because you are using PWM, the current is still at maximum in pulses, the maximum current is however reduced by the resistance of the PCB tracks.
revel:
Ok. so ideally I need to look at the trace length(s) and size them according the the current they are carrying.When the LED's are running at full blast they are pulling around 5A. Software dims them for the spin up time for the Zoetrope, then pulses them for 62 milliseconds on, 500 microseconds off for the 16Hz strobe at which point in time I read the aforementioned .1A in line at the 12V supply. But I have yet to measure at the PCB or individual drivers.
Since I do not have time to remake the PCB, and if indeed the trace size is a problem, I wonder if I can use two PCB's, with 5 buckpucks a piece, and control both of them with the arduino...
That would make a difference to the current on each PCB, I'm not sure if you have room to put some wires between the power inputs of each of the drivers to bypass the tracks.
Tom... 