Pre-Bias Soft Start

Definition

Pre-bias soft start is a power-supply feature that prevents discharging of the output capacitor when the power supply starts up.

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. Pre-bias soft start is 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.