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I am working on a high current MOSFET switch project. I would like to implement short circuit/overcurrent protection, that would be fast enough to prevent MOSFETs from blowing up. In the actual application, I am using HAL sensor to measure current, but it wouldn't allow me to take any action quickly, because of its delay. How should I realize this protection? Should I do it by using shunt and high-quality op-amp, there is any better solution?

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    \$\begingroup\$ Details of the MOSFET switch schematic are needed. \$\endgroup\$ – Andy aka Dec 30 '20 at 11:56
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    \$\begingroup\$ In terms of speed, shunt resistor will be hard to beat. \$\endgroup\$ – winny Dec 30 '20 at 12:09
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    \$\begingroup\$ How much is "high current"? How fast is "very fast"? \$\endgroup\$ – Justme Dec 30 '20 at 12:26
  • \$\begingroup\$ MOSFET switch is composed of 5 MOSFETs in parallel, with 22 Ohm gate resistance each and 1.5A driver. It has to handle 150A continuous current, has been tested on the bench. I don't know how long does it take to blow up MOSFETs while short circuit of battery (passing like 1-2kA), maybe I should ask question about what solution is the fastest one. \$\endgroup\$ – Bratw Dec 30 '20 at 12:36
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    \$\begingroup\$ A possibility would be placing a inductor in series that limits the speed at which current can ramp up, buying time for a overcurrent circuit to act. \$\endgroup\$ – Unimportant Dec 30 '20 at 13:22
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Use Vds detection with minimal dead time; drivers with short circuit protection use that methods.
EG for high voltage
https://gate-driver.power.com/products/scale-idriver-ic-family/sid11x2k/

If you have inductive loads or long cabling, detecting the current with a shunt is too slow and when you trigger the shutdown the current could take to much time to reverse. Specially with 5 Mosfet in parallel you can have problem to handle the energy in the circuit.

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