Here comes my question: is that delay (7us) short enough to protect the power Mosfets?
Maybe using a shunt resistor would be faster
My take on this is that during power up and power down (or severe brownout) in the PWM driver logic, conditions may not always be well defined.
I have had success with using opto isolator gate driver chips such as HCPL3120 and connecting the LEDs in direct inverse parallel.
It is then simply impossible for both LEDs to be be on together at the same time.
Its a very simple and robust solution.
What about a shunt in the +DC connection, before the de-coupling capacitors? What is your normal working current and DC link voltage?
A feasible implementation would probably go for a higher threshold voltage than 0.5 V and fast detection (e.g. 5 to 10 µs). Did you check the SOA for a safe threshold voltage?
I wonder why are you focusing on load shorts now? Load overcurrent protection, if it's intended to keep safe current limits for the load will most likely require a separate current sensor.
What about a shunt in the +DC connection, before the de-coupling capacitors?
Don't see a difference. Usual "desaturation" circuits are covering both cases.To make myself clear: I'm not talking about "desaturation" detection of a switching Mosfet but the Vds peak detection of a Mosfet in a steady conduction mode.
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