Guru
Joined: 09/08/2007
Location: AustraliaPosts: 4406
| Posted: 09:37am 01 May 2021 |
If I was living in a nightmare world where I had to drive ten mosfets in parallel, that is how I would probably do it. One driver chip per mosfet, up close and personal to each mosfet.
Or one driver and two mosfets with a symmetrical layout, almost as good.
Driving any more than two mosfets with one driver, and it all becomes vastly more difficult and trouble prone.
The trick then, is how to drive the inputs of the ten individual gate driver chips.
That could be done by use of a transmission line, correctly impedance matched at both ends so there will be no reflections or ringing. Each driver chip input can be distributed along the transmission line, because the input impedance will be quite high compared to the impedance of the transmission line.
The whole thing could be driven by a single opto source if galvanic isolation is required, and it should be.
This technique of driving multiple devices in parallel is called a "distributed amplifier" and is quite commonly used at microwave frequencies.
It also works at much lower frequencies where you need nice clean very fast edges without any reflections or ringing.
https://en.wikipedia.org/wiki/Distributed_amplifier