Half Bridge Mosfet works as a on/off switch with inrush limit NTC

Thread Starter


Joined Nov 27, 2021
I am planing to use a Half bridge mosfet BSM120D12P2C005 to switch 400VDC on and off.
but the switch to load has a long cable, it has a big inrush current with switch turn on.
circuit like this,

does it have any problem?
Thank you very much.



Joined Dec 2, 2017
I see a couple of problems.

First is your load should probably be located between the positive output of the power supply and the FETs. (unless having it in the source is deliberate)

Second when using MOSFETS in series you must make special considerations that the gates receive proper voltage.


Joined Jan 17, 2007
Also, the turn off sequence should be first turn off Fet 2 to make sure that current is going through the NTC before turning Fet 1 off ...

And yes, I second what ES said. Which translates to "it's better to place the load on the high side of the circuit and the transistors on the low side"

Thread Starter


Joined Nov 27, 2021
thank you both very much.
I am planning to use Tamura 2DD100206C gate driver, the voltage should have a proper voltage (floating voltage for individual FET)
the load is floating, in my point of view, it should be okay for high side switch.

any more suggestions?
thank you for your help, it is very appreciated