Abstract: A method of operating an access control system connectable to a power supply, including the steps of comparing the supplied power voltage to a threshold power supply voltage, determining a power-good condition when the supplied power voltage exceeds the threshold power supply voltage, determining a power-fail condition when the supplied power voltage does not exceed the threshold power supply voltage, and in response to the power-good condition: charging a capacitor to a capacitor charge not less than a threshold charge, and thereafter powering an electromechanical actuator, transitioning the access control system to a first state selected from locked and unlocked states wherein the capacitor charge is not less than the threshold charge upon completion of the transitioning, and in response to the power-fail condition: powering with the capacitor the electromechanical actuator and transitioning the access control system to the another of the locked and unlocked states.

Abstract: An illustrative access control system includes a locking assembly operable in locked and unlocked states, and a drive assembly operable to actuate the locking assembly. The drive assembly includes an electromechanical actuator, and energy storage device, and a control system. The electromechanical actuator is operable, upon receiving power, to transition the locking assembly between the locked state and the unlocked state. The energy storage device is electrically coupled to the electromechanical actuator, and configured to store electrical power from the power supply when the drive assembly is coupled to the power supply. The control system is configured to couple the drive assembly to the power supply in response to a first condition, and to thereafter transmit energy only from the energy storage device to power the electromechanical actuator, based at least in part upon a level of energy stored in the energy storage device.