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ADuM4135 Desat blanking switch not working

Question asked by andy.lau on Sep 27, 2017
Latest reply on Sep 28, 2017 by andy.lau

Hi Sir,


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?