Electronic Fuse

In the hectic of ‘just a quick test’ the voltmeter probe slips off the voltage regulator pin, causes a short circuit and a handful of expensive semiconductors to give up the ghost. Although the short-circuit proof benchtop power supply will protect itself, it will briefly pump enough current into the load to cause extensive damage. The circuit described here was designed to act as a fuse, but one that’s resettable, adjustable and fast-acting.Even a cursory look at the circuit diagram in Figure 1 should convince most of you that this is not the umpteenth run of the mill electronic fuse circuit. The ‘fuse’ is a BTS432E2 from Infineon, whose datasheets may be found at www.infineon.com/cmc_upload/0/000/008/685/bts432e2.pdf)