We are using ADuM4135 to drive SiC MOSFET H-Bridge Circuit. This is the gate drive circuit.
We got the problem that the desat pin voltage will reach to Vcc(20V). At this time the VI+ signal is low and VI- is grounded. We think this problem is because the blank switch (in red circle) is not ON when signal is Low, so the desat pin will be pull-up to Vcc through R6_3.
And after many tests, we found that the switch is not ON at any situation.
What can we do?