Electrical – Short Circuit Protection for Low Power Circuits without using a fuse

fusespowerpower supplyshort-circuitswitch-mode-power-supply

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

Best Answer

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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