The TLV61046A begins soft start when the EN pin is pulled high. At the beginning of the soft start period, the isolation FET is turned on slowly to charge the output capacitor with 30-mA current for about 2 ms. This is called the pre-charge phase. After the pre-charge phase, the TLV61046A starts switching. This is called switching soft-start phase. An internal soft start circuit limits the peak inductor current according to the output voltage. When the output voltage is below 3 V, the peak inductor current is limited to 140 mA. Along with the output voltage going up from 3 V to 5 V, the peak current limit is gradually increased to the normal value of 980 mA. The switching soft start phase is about 5 ms typically. The soft start funciton reduces the inrush current during start-up.