Hello,
Isolated DC/DC converters are used for a project. Allowed input voltage range is 18...36VDC for these DC/DC converters. Nominal input voltage is equal to 24VDC. Power supply 24VDC is used to supply different modules with RS485 interface. Each module consumes less than 150mA. We found a suitable protection circuit for pins A and B of the RS485 transceivers based on TVS (Transient Voltage Suppressor), TBU (Transient Blocking Unit) and GDT (Gas Discharge Tube). Reference document is attached.
Inputs of the DC/DC converters should also be protected from 230VAC. Unfortunately this protection circuit is not suitable for protection of the 24VDC input without modifications.
It is desirable not to replace components after faults. In our opinion, PTC resettable fuses are not suitable for this purpose because of high peak currents.
What can you suggest?
Best regards,
Vitalij