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For low power circuits (24V, 250mA, approx. 6W), what is a good method to provide short circuit protection without using a fuse or a PTC re-settable fuse.

As far as I know, those are the two main methods and the oracle (google) has failed me in terms of finding any alternative approaches so I figured i would ask stackexchange.

Does anyone have any experience with providing short circuit protection without the use of fuses (for low power circuits).

Thanks

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    \$\begingroup\$ This smells like an XY problem, it might be useful to know why you don't want to use a fuse. \$\endgroup\$ – PlasmaHH Jul 6 '17 at 15:38
  • \$\begingroup\$ A simple current-limiting circuit is an option. Such circuits are often used on power supplies. Try searching for current-limiting. \$\endgroup\$ – Leon Heller Jul 6 '17 at 15:52
  • \$\begingroup\$ It's application dependent and circuit dependent neither of which you have explained. \$\endgroup\$ – Andy aka Jul 6 '17 at 16:21
  • \$\begingroup\$ Self biased JFET current limiter comes to mind. \$\endgroup\$ – winny Jul 6 '17 at 18:06
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Current limiting inside ICs can occur in 10 nanoSeconds or 20 nanoseconds. YOu need a sense resistor (zero time), a comparator (5 to 10 nanoseconds for moderate power comparator), and circuitry to shut off the MOSFET switch (5nS to 20nS).

Do not use overtemperature monitoring to protect the IC. Its too slow, because of need to propagate heat through the silicon substrate, unless the heat sensor is located next to the power device (within 10 microns).

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In many microelectronic systems, power rails are provided by DC-DC converters that have their own current limiting functionality. A reasonably featured LDO or buck converters, for example, will usually include a fixed current limit. More highly featured regulators might have a programmable current limit threshold.

For power sources that don't have a built-in current limit (a battery, for example), a fuse or re-settable fuse is typically used. In some situations, more sophisticated solutions using dedicated protection controller IC's may be employed. You can find these types of ICs marketed as surge stoppers, overcurrent controllers, circuit breaker controllers, etc. However, this approach would not usually be required for low-power loads like yours.

In short, consider an LDO with an appropriate current limit for your situation. You can run the LDO in drop-out so that it eats up only a tiny portion of your supply

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