In another question (DC-DC booster fails with lead-acid battery source) I described a problem with a DC-DC booster that destroyed itself by dragging a large current when its output was disconnected.

This did not happend when the power source was a sw-mode (maybe due to its overload circuit), but when a Lead-acid battery was used who could deliver large burst current (>40A).

Apparantly this is a consequence of the DC-booster design. So I need some shut-off circuit which could be a resettable fuse, but I think that this is somewhat a primitive solution.

Maybe its possible to use some power FET, but im not much into how to design control a shut-off state at, say at 8A - and certainly not to make it well working.

  • \$\begingroup\$ Unless he can implement a soft start in the regulator a solution could be an “ICL surge limiter” for startup only but for cutoff UVP is needed or switch the input to Reg \$\endgroup\$ Jul 4, 2018 at 15:44
  • \$\begingroup\$ Resistor + relay. But soft start is way better. \$\endgroup\$
    – user76844
    Jul 4, 2018 at 15:47
  • \$\begingroup\$ Inrush? Maybe flyback protection from inductive wire current? \$\endgroup\$ Jul 4, 2018 at 15:49
  • \$\begingroup\$ I could put another of the same DC-booster in front of the original that could limit the current of the original that want to destroy itself (both have pots for controlling the current). The front DC-DC will never have its output disconnected as it feeds the original ;) \$\endgroup\$
    – Gearlos
    Jul 4, 2018 at 15:55
  • \$\begingroup\$ Or maybe a couple of LM317 in current limiter mode. I think I can remember this shown in the fab. specs \$\endgroup\$
    – Gearlos
    Jul 4, 2018 at 16:00


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