The advantages of this novel precise step-shaped soft- start technique for integrated dc-dc converter are not only owning excellent constant peak current limiting capacity for any load conditions to diminish initial inrush current powerfully but also solving the over-voltage or drop-voltage problem during the changing between the start-up mode and normal operation. Furthermore, the on-chip design for this technology reduces the numbers of the external I/O pin to decrease the cost of the converter. Therefore, this novel soft-start technique is more available and smoother for integrated dc-dc converter than the conventional soft-start technique.