Power Supply Device Current Limiting Resistor Startup Control

The patent applies preliminary action by detecting the startup state before normal operation begins and activating the current limiting unit in advance during this initial period. The phase angle detection unit identifies when the AC voltage is in its initial half-cycle, and the control unit ensures the current limiting unit remains active during this predetermined time period. This preliminary activation prevents high inrush current from flowing into the uncharged capacitor before the charging process completes, while allowing the current limiting unit to be suspended later to reduce power loss during steady-state operation.

The patent implements periodic action by making the current limiting unit operate intermittently rather than continuously. The control unit suspends the current limiting unit during normal operation when phase angles indicate steady-state conditions, and activates it periodically during specific phases such as startup or when abnormal current conditions are detected. This periodic activation pattern maintains inrush current protection when needed while minimizing power loss during normal operation by keeping the current limiting unit suspended during non-critical periods.

The patent applies feedback by using the phase angle detection unit to continuously monitor the AC voltage phase angle and provide this information to the control unit. The control unit uses this feedback to determine whether to activate or suspend the current limiting unit. During startup, the feedback mechanism ensures the current limiting unit remains active until the capacitor has been sufficiently charged through the initial half-cycle, preventing premature suspension that would cause high inrush current. Once charging is complete, the feedback allows the control unit to suspend the current limiting unit for efficient operation.