Pre-bias soft start has become an important feature in redundant power supply systems, parallel power supply modules, battery back-up voltage buses, and other applications where multiple power sources supply one node. Specifically, pre-bias soft start ensures that no output capacitor discharging occurs during the soft start period of a dc/dc converter. Discharging the output capacitor could create either start up oscillation problems at cold start or large voltage disturbances on the output voltage bus at hot plug-in. Preventing output capacitor discharge has become a common requirement in point-of-load power supply designs. ……