Capacitive voice coil actuator retract device with crash stop bounce detector

摘要

A self-sufficient electronic device to retract and park a voice coil actuator in a resistive parking position in,hard disk drives whose kinetic energy obtained from the rotating disk stack is not sufficient to be utilized as an energy source for the power-off retract and parking of the actuator. The invention uses electric energy stored in one or more capacitors to perform the necessary tasks. An initial electrical pulse is imposed on the actuator to propel the actuator towards a resistive parking ramp. In the event the actuator bounces off a crash stop barrier a bounce detector recognizes a polarity change of a reactive voice coil voltage and gives a signal for a secondary energy pulse to return the bouncing actuator to the resistive parking position. The simple logical concept of the device conserves space and energy making it suitable for miniature hard disk drives.