Experiment Based Empirical Model for SMD Fuse under Pulsed Current Excitation

SMD fuse is being widely used as over-current protection device in electronic systems and their switching power supplies. The vulnerability of the SMD fuse operation to its thermal ambience deviates its opening time response from Time-Current Characteristics in the datasheet and poses challenges in estimating the fuse-opening time necessary for the fuse selection. To take the deviation into account, an experimental data-based empirical fuse model is proposed. The model is tuned using the experimental Time-Current Characteristics captured from simple and reproducible constant current fuse blow experiments. The switching-current fuse-blow experiment performed to verify the model in a switching-power converter environment also reveals that the switching nature of the fuse current does not impact the fuse operation significantly. Also, RMS values of the switching current that opens the fuse in the experiments and that are predicted by the model have a small error of 10%.