I am using ADuM4135 for 3phase inverter circuit to drive IGBT module.
ADum4135 toggles fault pin low even if voltage at desat pin is not exceeding 9V.
Does this occur all the time, or at high power? Is there a specific operating point that you notice this occurring more?
Yes, it occurs when I use 150V source, at 70V source it works fine.
Does fault pin toggle due to miller effect (i.e. more than 2V at gate pin) or fault pin toggles only during desaturation condition ?
The ADuM4135 does not register a fault in reaction to the Miller effect. It should only give a fault when the DESAT pin goes above the ~9V threshold. We have seen some spurious DESAT registration in systems near large RF sources. I'd like to follow up on this with a direct email. I'll contact you soon.