Hey guys I'm currently designing a schematic for a super capacitor spot welder and I'm working on the control system for the MOSFETs.

I'm planning on using a gate driver instead of just resistors and zeners because of the very high burst current (couple hundred amps for 10 to a couple hundred milliseconds) and the heat the transition time would create.

Pretty much just having some trouble deciding what driver IC to use. I was using THIS filter to find some ICs and it helped, but there's still a lot of choices.

THIS was one of the first choices on there and it seemed like a good choice, but like I said idk.

I'm planning on just putting 4 MOSFETs in parallel and driving all their gates with the single channel of that IC.

Anyways if anyone has any advice on which IC to use that would be great.


closed as off-topic by Neil_UK, Enric Blanco, Brian Carlton, Voltage Spike, PeterJ Jun 27 '17 at 13:26

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  • \$\begingroup\$ Product recommendation are off topic for this site. Besides, there's not nearly enough info for the switching time you want to achieve at the FET gates to provide any clue as to what driver would meet those specs. I'd be inclined to use a small driver per FET, rather than a large driver shared between them all, but that's just me, and opinion based! It could degrade their difference in switch on times slightly, makes tuning that out possibly easier, shares a low current rather than high current connection. \$\endgroup\$ – Neil_UK Jun 26 '17 at 7:18

I would consider using an SCR on the discharge side for this type of circuit instead of a FET - particularly if you are not trying to do precise dwell times. The SCR is capable of handling very high di/dt, is easily triggered, and is self extinguishing when the cap voltage drops..

You mentioned that you are using supercaps as the welding current source. Keep the internal resistance in mind as this limits the maximum discharge current due to self heating. You will find low ESR caps but you must be selective. The datasheet will list the maximum discharge current.


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