Power Supply Soft Start Controller Undershoot Prevention

The patent applies preliminary action by detecting the transition from skip cycle mode to normal operating mode in advance and preemptively adjusting the soft-start reference signal. When the controller detects that it is exiting skip cycle mode, it immediately modifies the soft-start reference signal to prevent undershoot before it occurs, rather than reacting after the undershoot has already happened. This anticipatory adjustment allows the output voltage to maintain regulation during the transition without the typical dip and prolonged recovery.

The patent applies preliminary anti-action by implementing a mechanism that counteracts the impending undershoot effect. The controller monitors the operating mode transition and, upon detecting exit from skip cycle mode, immediately adjusts the soft-start reference signal to compensate for the expected current limitation. This counteracting action prevents the undershoot from occurring in the first place, rather than attempting to correct it after the voltage dip has already affected the output.

The patent applies dynamics by making the soft-start reference signal adaptive rather than static. The controller dynamically adjusts the soft-start reference signal based on the operating mode state. During normal operation, the soft-start function operates slowly for safe current regulation. However, during transition from skip cycle mode, the system dynamically modifies the reference signal to enable faster current increase, allowing the load transient response to improve while maintaining current regulation safety through controlled adjustment.