ACTUATOR RETRACTION CIRCUIT

摘要

Method and apparatus for retracting an actuator comprising determining back emf voltage generated by the actuator motor (20); applying the determined voltage to a capacitor-resistor network (26); applying a holding voltage to the capacitor-resistor network (26). The application of the determined voltage and the holding voltage together charges a capacitor (c) in the capacitor-resistor network (26) to develop a charged capacitor voltage. The method and apparatus further comprises terminating application of the determined voltage to the capacitor-resistor network (26) upon charging of the capacitor (c) and discharging the capacitor (c) through the capacitor-resistor network (26) to provide a forcing voltage to the actuator for retract operation. The forcing voltage initially forces a high deceleration current in the actuator. Further, the forcing voltage decays with time to a predetermined holding voltage to complete the retract operation.