I've got an interesting problem here, and was wondering if anyone wanted to throw in suggestions about how to best implement the solution.
I'm trying to build a PWM controller for a 12v @ 100a motor (Yep). I've found a MOSFET that should do the job:
A rheostat isn't a workable solution, weird stuff seems to happen to the torque profile on the low end of the speed range.
The question is, how do I go about designing a PCB around this thing that'll take the current while sticking with FR4 and standard manufacturing processes (ie. a two layer board via OSH Park)?
Some calculations show I would either need 23cm trace widths, or a PCB with 100oz copper layers.
My immediate thought was to add a couple standoff holes at both ends of the traces and screw down bus bars - pretty sure that'd be a workable solution, but I'm not sure how wide the traces should be in the small area between the MOSFET's legs and the beginning of the bus bar.
The second thought, would be punching vias along the entire length of the trace, with an identical trace on the bottom layer of the board. Fill the vias with solder, and that should emulate a very thick power line.
As well, it doesn't seem like the legs on a TO-220 package should be able to take that kind of power without melting, but I guess with a big enough heatsink it should be fine... I'm thinking an enthusiast CPU cooler and big 12v fan should do the job.
So, how crazy am I?