The STEVAL-ISA126V1 is a 5 V-2 A application with 3.3 A peak current capability for 1.9 sec, using VIPer28H, a new off-line high voltage converter from STMicroelectronics. In some applications an SMPS, normally supposed to deliver a certain amount of power, from time to time undergoes load peaks that can be even two or more times as much, but only for a time interval which is short if compared to the thermal time constants of the power components. Typical examples of such loads are printers and audio systems.
In these cases, it is more cost-effective to thermally design the system for the maximum continuous power and not for the peak power demand, which will be sustained only for a limited time window.