I have a design running on 24V SLA batteries using STEF01 fuses for protection of the lower powered rails and an LT4356 using external MOSFETs for a 25Amp rail.
That 25A rail is giving me headaches. Staying within the SOA of the MOSFETs is not that easy when the output is started up shorted, and even though it works on the bench it fails from time to time in the field. The STEF01 fuses have been performing flawlessly.
Now, the load on the 25A line is a parallel wound DC motor and an external motor controller. The field winding is powered directly from the 25A line, the armature is powered by external electronics which takes some time to power up. Thus, the load on the 25A line is both a large capacitance (external electronics input capacitance; 3000+uF) parallel to a large inductor (oh joy. Yes, I do have transient voltage limiting..). I cannot change this arrangement.
I wonder if I could parallel 5 or 6 STEF01 fuses by interconnecting UVLO/dvdt/Vclamp/EN lines and eventually adding current sharing resistors between the separate Vouts and the common to raise the current capability? It is a bit of a crude and somewhat expensive solution but it is already in the BOM, our software guys already have support for that, and so far the STEF01 has been reliable.
TI seems to allow parallel operation of multiple Efuses (https://www.ti.com/lit/an/slvaf13/slvaf13.pdf) so the idea is not that far fetched. I searched for a similar appnote on STEF01/ST efuses but have not found any.
Is this possible and reliable?
