Thanks for explaining. Do you know if there are reliability differences between low side and high side switching?
Donât really remember much difference, just as I have worked with auto/moto industry high side is preferred way because of ground loops/cases and etc. Low-side is the easiest to make as it doesnât need charge pumps and etc. But if you have somewhere ground available is bit pain in the ass because you have to make sure your electronics will not get ground from anywhere else not through communications ports like CAN and etc 
Good discusion happening here:
For an isolated circuit, no there is no great difference between high and low-side switching. For higher load currents, low side semiconductor switches (for example NPN transistors and N-channel MOSFETs) are often less lossy than their high-side equivalents, and so are preferred.
However, if the circuit is connected to external devices with their own power connections, this becomes blurred. If these external devices provide a connection to the same ground reference as the power supply to the circuit and you switch this in and out then the external devices will provide an alternate route to ground, your switching will be ineffective and you may end up damaging something not rated for the appropriate current along the way.
Similarly, if the external devices provide a V+ supply which is referenced to the same ground as the supply that you are switching, you can end up back-powering the positive voltage rail via the externally powered devices, again with undesirable results.
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Getting back to the precharge discussion, I was thinking that integrating this switch directly on the vesc would have this advantage: we could use the soft-swicth to also enable the drv (and put some delay to enable lt4356). This way we could use drv buck converter to do the precharge of the caps, eliminating the inrush problem when lt4356 wakes up. What do you think?
I was more concerned with the total footprint than anything else. 6 FETs will need much more space than a single fatboy one. Itâs also the reason why I donât like the Vedder ones - they are just so huge for what they do. Until @kuglis nobody used the vertical space available (I am obviously talking about use cases where you would not need the aluminium block (in for example low power commuter boards))
They are 5 by 6 mm. So 3cm long when they are placed in line. (max 3.5cm if you space them properly)
Update. I have added the precharge function with a cheap and reliable 555 timer. I also made a first pcb draft; the soft switch function has been left out temporarely to achieve a compact design and a single side smt assembly. The whole thing will be open source after testing prototypes. I may also incorporate it into the escalate pcb.
@Maxid I layed out the design in a way that allows the user to cut off one or more mosfets without altering the functionality, like you would do with an LED strip.
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I would reccomend independent 10-20 ohm gate resistors for each parallel FET.
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I assumed that few fets with low gate charge would be equivalent to having a big fet; thus I only placed one resistor. A quick research revealed that I was wrong since the resistor also suppresses the gate oscillation if you have high inductance in the gate trace. Thanks for the tip.
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Well its all good if you have switching load, here we have a constant on/off so there will be not much oscillation as it will be always on
I thought the same, especially with the slow-ish turn on of the gate. But I had some really strange behavior going on with my switch which seemed to disappear when I added individual gate resistors close to each FET and things quit exploding. It isnât much cost or real-estate anyway.