Maybe the patent describes a higher level something. I recall they use a particular feedback (or was it feedforward) overshoot management loop, and they happened to describe how the actual hardware was laid out, and with a couple of pictures I may have figured it out. Or maybe not, we'll find out way after I test the basic stuff.
Someone posted something about being silly about not seeing the desat circuit, and his signature linked to a good thread about a diy gate driver that I didn't read before. Spent quite some time today reading the complete thread on the phone and something caught my attention. A dude found that his desat does not work at high temperature because this diode sinks all the desat blanking current as reverse leakage current.
In a sense, that would affect me too.
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It looks like at 100°C half the current coming from the internal 500uA current suply is sunk in the diode, so the blanking time last twice the time if I'm reading this correctly.
In the case of the avago gate driver that has a 250uA current for the blanking time constant, since the diode sinks 250uA it gets stuck on that blanking time and you get no desat protection. My TI gate driver would just have the desat disabled for 4us instead of 2us, for example, and completely disabled at near 120°C.
This is not going to reach such high temperatures. 100°C or even 85°C in the gate driver pcb is way too much for my taste, there are electrolytic caps on board that should live a long, cool life. But hey, this came from seemingly nowhere and it could have hit me big time if I had a poorly chosen schottky diode.
So thanks to the dude who pointed me to that thread. Schottky reverse currents are something to keep in mind.