How to balance protection and EMC in power FTU switches?

Balancing switching protection and EMC considerations requires a balance between operating speed and filtering. Overcurrent protection employs a fast comparator with an RC delay (10μs), coupled with ESD 5V 0D8B protection. Overvoltage protection uses a TVS diode SMBJ24CA in parallel with a Zener diode. Protection signal filtering utilizes a second-order low-pass filter with a cutoff frequency of 1kHz, ensuring a response time of less than 20ms. PCB layout: The protection circuit is kept away from interference sources and uses an independent ground plane. Shielded twisted-pair cables are used. This design achieves a protection operating time dispersion of less than 5ms, while simultaneously meeting the IEC 60255 protection standard and the IEC 61000-4-4 EFT 4kV immunity requirements.