Abstract: Actuation systems and devices using an electrically deformable material are disclosed. In the embodiments, a bidirectional actuator assembly includes a first unit including an electrically deformable material coupleable to an activation voltage and configured to provide a displacement in a first direction when the activation voltage is applied to the first unit. A second unit is serially electrically coupled to the first unit and includes an electrically deformable material coupleable to the activation voltage and configured to provide a displacement in a second direction that is different from the first direction when the activation voltage is applied to the second unit. A unidirectional actuator assembly includes at least one unit including an electrically deformable material coupleable to an activation voltage, wherein the electrically deformable material provides a displacement in a selected direction when the activation voltage is applied to the at least one unit.

Abstract: A method of controlling the velocity of a voice coil motor (VCM), including sensing a voltage difference between the VCM and a sense resistor and driving a velocity control loop (VCL) based on the voltage difference. There is also a control loop circuit, including a current output connected to drive a voice coil motor, the voice coil motor producing a back electromagnetic field (BEMF) voltage. The circuit also includes a sense resistor connected to the BEMF output, and a BEMF resistive network comprising a first resistor and a second resistor. The circuit also includes a velocity control loop (VCL) connected to control the voltage output according to a voltage difference between (i) a junction of the sense resistor and the current output and (ii) a junction of the first resistor and the second resistor.

Abstract: A method of controlling the velocity of a voice coil motor (VCM), including sensing a voltage difference between the VCM and a sense resistor and driving a velocity control loop (VCL) based on the voltage difference. There is also a control loop circuit, including a current output connected to drive a voice coil motor, the voice coil motor producing a back electromagnetic field (BEMF) voltage. The circuit also includes a sense resistor connected to the BEMF output, and a BEMF resistive network comprising a first resistor and a second resistor. The circuit also includes a velocity control loop (VCL) connected to control the voltage output according to a voltage difference between (i) a junction of the sense resistor and the current output and (ii) a junction of the first resistor and the second resistor.

Abstract: A method for controlling a motorized data-storage device, including extracting energy from a spindle motor to drive a positioning motor of the data-storage device and other components, such as circuitry. In normal operation of one embodiment, a disk is rotated at a constant velocity by a spindle motor and a read/write head is moved over the disk surface by a voice-coil motor. In the event of a power failure, energy is extracted from the spindle motor to drive the voice-coil motor so the head can be safely moved away from the disk.

Abstract: A power loss retraction architecture is provided to retract the VCM arm of a hard disk drive upon power loss. The power loss retraction architecture is configurable to be able to use energy from different sources. The selected energy source is used efficiently by applying the energy only to the VCM retract arrangement, while isolating the energy source from other circuits that are not needed to accomplish the retraction operation.

Abstract: A system for controlling the speed of an arm of a disk drive, including a feedback circuit for generating a feedback signal representative of the speed of the arm, and a drive circuit for comparing the feedback signal with a predetermined command signal representing a command speed, and adjusting a drive signal for a motor to drive the arm at the command speed. The feedback signal, which represents the back EMF of the motor, is compared with the command signal to determine an acceleration state of the arm and the acceleration state is used with a previous acceleration state to determine whether to adjust a predetermined level at which the motor is driven.

Abstract: A multi-mode motor controller architecture includes a motor, an integrated circuit controller, and an integrated circuit driver circuit. The integrated circuit controller includes a pulse generator, a DAC, an ADC, and a digital compensator circuit. The integrated circuit driver circuit is in communication with the controller and includes an error amplifier, first and second output amplifiers for driving the motor, and a sense amplifier. The motor controller architecture is configurable to operate in a linear mode, a pulsed mode, or a switchable linear/pulsed mode. The controller architecture can be implemented with external compensation circuitry, such as a resistor-capacitor circuit, or with the digital compensation circuitry located within the controller integrated circuit.

Abstract: A multi-mode motor controller architecture includes a motor, an integrated circuit controller, and an integrated circuit driver circuit. The integrated circuit controller includes a pulse generator, a DAC, an ADC, and a digital compensator circuit. The integrated circuit driver circuit is in communication with the controller and includes an error amplifier, first and second output amplifiers for driving the motor, and a sense amplifier. The motor controller architecture is configurable to operate in a linear mode, a pulsed mode, or a switchable linear/pulsed mode. The controller architecture can be implemented with external compensation circuitry, such as a resistor-capacitor circuit, or with the digital compensation circuitry located within the controller integrated circuit.