Switched-Mode Power Supply Self-Locking Circuit

The patent applies preliminary action by charging a capacitor with control voltage before power failure occurs. This stored voltage in the capacitor maintains the control element in its conducting state during power interruptions, ensuring the switched-mode power supply remains activated and ready to operate immediately when power is restored, thus maintaining reliable self-locking while allowing the converter to be disconnected during normal operation for energy efficiency.

The patent implements periodic action by intermittently connecting the voltage converter to the power supply rather than maintaining continuous connection. The converter is activated periodically to recharge the capacitor when voltage drops occur, and disconnected during stable operation to minimize energy consumption. This periodic charging strategy ensures the control unit remains reliably powered through the capacitor's stored voltage while significantly reducing overall power consumption.

The patent applies self-service by enabling the system to automatically restore and maintain its own operation without requiring continuous manual intervention. The capacitor stores control voltage that automatically keeps the control element activated after power failure, and the system autonomously recharges the capacitor when voltage drops occur. This self-sustaining mechanism allows the system to automatically restore power after failures without requiring the user to press the button again, while still permitting manual activation when needed.