Abstract: The present invention utilizes the output of a voltage regulator to control the drive voltage to the stepper motor driven transducer positioning system. This technique will significantly reduce the access time. More specifically, in this invention, the output of a digital-to-analog converter (DAC) is used to control the output voltage level of a voltage regulator circuit which supplies the voltage of the stepper motor drive transistors. In order to optimize the drive voltage output from the voltage regulator to the stepper motor for each disc drive, circuitry is provided to determine the minimum settling time for a specific actuator movement resulting from the application of a given drive voltage. A detector circuit monitors the settling time of the head over the center of the target track. The data identifying the voltage regulator output which results in minimum settling time is stored and used from then on for that stepper motor disc drive system as the optimum access tuned voltage.

Abstract: The output of the ring detector is used to change or control the timing of specially generated torque damping pulses which are fed to the stepper motor at the end of a SEEK step sequence. These torque damping pulses are step pulses, the timing, amplitude and/or duration of which applies either a positive or negative torque to the stepper motor relative to the target track based on the "energy" that has to be dissipated to settle the read/write head over the desired track. The energy is measured indirectly by monitoring the back emf voltage of an open winding or unenergized phase of the motor, and developing an indication of how fast the read/write head is going through the desired track center or target track point. By bringing an additional signal out of the ring detector, the direction in which the read/write head has crossed the track can also be defined.