Abstract: In accordance with one embodiment of the described technology, a retract controller capacitor is charged using a back electromagnetic force voltage to produce a backup power source voltage, the retract controller capacitor is discharged to power a retract controller circuit, and an actuator arm of a storage drive is driven toward a desired location concurrently with the discharging operation.

Abstract: In accordance with one embodiment of the described technology, a retract controller capacitor is charged using a back electromagnetic force voltage to produce a backup power source voltage, the retract controller capacitor is discharged to power a retract controller circuit, and an actuator arm of a storage drive is driven toward a desired location concurrently with the discharging operation.

Abstract: An apparatus and associated methodology for retracting a first member in relation to a second member. The first member may be selectively moveable by a first motor and the second member may be selectively moveable by a second motor that operably generates a back electromagnetic force (BEMF) voltage VBEMF. In an embodiment a retract control circuit may control movement of the first member via the first motor in response to a loss of supply power to the second motor. An embodiment of the apparatus may include a backup power source storing a voltage VB after the loss of supply power. Another embodiment of the apparatus may include retract logic operative on the retract control circuit to divide the VB from the VBEMF to energize the first motor by the VBEMF and not the VB when the VB is greater than a predetermined threshold voltage and a loss of the supply power to the second motor is detected.

Abstract: A reverse torque, forward commutation motor driver system for a phased motor rapidly decelerates or “brakes” the motor by exciting, in sequence, a complementary excitation signal in each normal commutation state of the forward state machine, thereby providing an active braking effect. After active braking reduces the rotational velocity of the motor below a threshold, a dynamic braking technique can replace the active braking, wherein high-side drivers are set to an opposite voltage as compared to low-side drivers.

Abstract: A system for hardware intelligent speed monitoring and auto-retract is disclosed. The system contains a monitoring device that monitors the TACH (Tachometer) output of motor driver. The device provides a trigger to the signal processor and a retract mechanism to retract the actuator when the spindle motor speed is unexpectedly much higher or lower than normal speed. The system DSP (Digital Signal Processor) is unaware of such occurrence.