/diy/ - Do It Yourself

>>2520768
MOSFETs act in the ohmic region when fully switched on, and have a normal positive tempco, so running them in parallel is fine. Usually you give them seperate gate resistors from what I've seen, but you may want to look into that since I'm not sure it makes sense. If switching losses are an issue you may even want to use seperate gate drivers, as to not split gate drive current up too much.
Saw a welder with like 16 IRF540s in parallel on TPAI's youtube channel, which was kinda funny.

>I can't see how he can do this without parallel power FETs
I'm also designing a simlilarly powerful motor controller, running on 12S lipos, though only to half the current since I'll be driving two wheels. Assuming it's still in stock, I plan on using the TPW1R306PL MOSFET by Toshiba, it's rated at 100A continuous, though in reality that's a function of heat-sinking. It's a real modern part with the ability to strap a heat-sink directly on top of it, that can operate up to 175C. Assuming 25C ambient, that's ∆T=150C, and it has 0.93C/W thermal resistance to a heat-sink atop it. I plan on using 6 of them (BLDC) with a 1C/W heat-sink, so that's 6C/W when split up, 7C/W total when including the FET itself, meaning maximum of 21W. The FET's gate resistance gets up to 2mΩ at 175C, so through P = R*I^2 we get I = √(P/R) = √(21/0.002) = 102A. So yeah it's possible, arguably even cheaper than parallel FETs.
There are better MOSFETs out there, but they don't have the upper thermal pad, so you'd only get that kind of performance if you mount them to an aluminium-backed PCB. Which is arguably worth doing, but note that JLC only does single-sided aluminium-backed boards, so getting your entire driver circuit on there is more or less infeasible. I think PCBway or someone else does multi-sided ones.

Wait shit it's on back-order everywhere.