Texas Instruments Corporation

John Kevin Rote

Seil Oh

Brian Lee Schmidt

Gregory Swize

Joao Carlos Brito

Tuan Van Tran

Frederick W Trafton

Juergen Luebbe

Mehedi Hassan

Bertram John White

Marcus Marchesi Martins

David R Street

Robert E Whyte, Jr

Tan Du

Degang Xia

Joao Carlos Felicio Brito

Quang Dieu An

Tanchu Shih

Joao Carlos F Brito

Liyong Chen

Jasraj R Dalvi

Lindian Wayne Reynolds, Jr

A circuit includes a driver circuit having a high side switch device and a low side switch device coupled to a load voltage node and a motor winding output. A controller operates the high side switch device and the low side switch device. The controller operates in a normal mode to supply current to the motor winding output for driving a motor winding when an external power supply is available to supply the load voltage node. In response to detecting a loss of the external power supply, the controller operates the high side switch device and the low side switch device in a boost mode to utilize a back electromotive force (BEMF) voltage from the motor winding to supply current to the load voltage node.

Configuration, frequency registers generating power from motor in supply-loss event

Systems and methods for increasing Pulse Width Modulation (PWM) resolution for digitally controlled motor control applications are described. For example, in some embodiments, a method may include receiving a clock signal having a given period; identifying a target duty cycle; calculating a comparison point based upon the given period and the target duty cycle; generating a PWM signal based upon the clock signal using the comparison point; and varying the comparison point to increase a resolution of an effective duty cycle of the PWM signal.

Increasing PWM resolution for digitally controlled motor control applications

A quiet motor control system is described. This system digitally determines modulated voltages applied to motor phases in a manner that compensates for winding torque distortions, which reduces acoustic emissions.

Quiet motor control system

To achieve peak acoustic and power performance, the coil or applied current should be in phase or substantially aligned with the back electromotive force (back-EMF) voltage. However, there are generally phase differences between the applied current and back-EMF voltage that are induced by the impedance of the brushless DC motor (which can vary based on conditions, such as temperature and motor speed). Traditionally, compensation for these phase differences was provided manually and on an as-needed basis. Here, however, a system and method are provided that automatically perform a commutation advance by incrementally adjusting a drive signal over successive commutation cycles when the applied current and back-EMF voltage are misaligned.

Method and apparatus for applying a commutation advance automatically in a brushless DC motor

A power regulator system is described. The system includes a switching system comprising at least one switch and an inductor, the switching system being configured to provide an output voltage based on a current through the inductor. The system also includes a switch driver configured to provide a switching signal to the switching system to control the operation of the at least one switch to provide the current through the at least one inductor. A mode controller is configured to switch the switch driver between a continuous mode of operation and a discontinuous mode of operation based on both a feedback voltage associated with the output voltage and at least one other predetermined operating condition associated with each of the continuous and discontinuous modes of operation.

Combination continuous and discontinuous control of a power regulator

A circuit () and method are presented to accurately determine a BEMF voltage of a VCM coil () after termination of a driving current in a first current direction in the coil (). The circuit includes a circuit for activating selected VCM coil driver transistors () to apply a current to the coil () in a direction opposite the first current direction to generate a magnetic field to oppose eddy currents established in structures adjacent the coil () by the driving current. The time that the eddy current opposing current may be applied may be determined, for example, by determining a magnitude of the original current command, a time that the coil spends in flyback, or a magnitude of the original driving current, and adjusting the time of application of the eddy current opposing current accordingly.

Method and circuit for operating a voice coil actuator of a mass data storage device

Disclosed are methods and apparatus for digital control of a head-disk assembly actuator with dynamic velocity compensation. In preferred methods of the invention steps are disclosed in which, the actuator voltage in an HDA is sampled and a velocity error is determined. The voltage applied to the actuator is compensated for the velocity error. Disclosed methods of the invention also include steps for measuring the actual voltage at the actuator motor and alternatively, for calculating the actuator motor voltage using digital processing techniques. A digital voltage command is then provided for applying compensated voltage to the actuator motor. Apparatus for implementing the methods of the invention in a hard drive assembly having an actuator motor is also described. The apparatus includes a sampler for sampling an actuator motor voltage, a timer, and a digital processing engine for receiving a target actuator voltage command and the digital actuator motor voltage sample and for outputting a digital voltage command for controlling the actuator motor.

Digital actuator control and method

A system and method of motor control enable improved motor control by controlling a phase winding to float or enter a high impedance state prior to activating phase detection of the phase winding. Because the phase winding floats prior to phase detection, the effect residual current coupling in such phase can be mitigated and thereby help improve motor operation.

System and method for improved motor control

A system and method are provided for controlling operation of an actuator for retracting a read/write head of a hard disk drive system. One aspect of the system and method relates to controlling the actuator in response to a retract request command by first decelerating the actuator for a time period and then braking of the actuator for another time period. Another aspect of the system and method relates to controlling operation of the actuator during retract based on a sensed back EMF relative to a target back EMF, which may be selected by a user.

System and method for controlling an actuator motor during retract

A method is disclosed for controlling the voltage applied to a voice coil motor coil during the retract operations of a mass storage device, comprising a combination of three different voltage regulator stages. This method includes providing a first circuitry stage adapted to source current to a voice coil motor apparatus, raising the voltage across the voice coil motor to a desired level, providing a second circuitry stage adapted to draw current from the voice coil motor effecting a desired voltage across the voice coil motor, and providing a third circuitry stage adapted to raise the voltage of the voice coil motor to ground by effectively shorting the voice coil motor to ground.

System for voltage regulation of a voice coil motor

An actuator (,) has a movable member (,), and has a coil (,) which can be controlled to urge the member to move. In a particular mode of operation, a driver circuit (,) is periodically uncoupled from the coil so that the current through the coil goes to zero, after which the back-emf voltage of the coil is applied to a capacitor (,). Then, the driver circuit is recoupled to the coil, and the voltage held by the capacitor is used to effect feedback control of the driver circuit for the coil.

Method and apparatus for accurately measuring a back-emf voltage on an actuator coil

An apparatus for controlling an actuator in response to a target speed voltage signal, the actuator having a moveable member and having a coil that influences movement of the member. A first summing node is provided having a control output voltage, for summing or subtracting voltages applied thereto, as the case may be and receiving the target speed voltage signal at a first, summing input thereto. A proportional compensation unit is provided, receiving the control output voltage and providing as an output a proportionally compensated output signal. An integral compensation unit is provided, receiving the control output voltage and providing as an output an integrally compensated output signal. An inverse compensation unit is provided, receiving the target speed voltage signal as an input and providing an inversely compensated output signal having a voltage corresponding to the voltage of the target speed voltage signal multiplied by the inverse of a predetermined amplification factor. A second summing node is provided, receiving the proportionally compensated output signal, the integrally compensated output signal and the inversely compensated output signal, and having a command output signal corresponding to the sum of the input signals. An amplifier is provided, receiving the command output signal and having a drive output signal for driving the actuator. Finally, a sense unit is provided for sensing a back-EMF of the actuator and providing a voltage corresponding to the sensed back-EMF to a second, subtracting input of the first summing node, such that the control output voltage corresponds to the difference between the target speed voltage and the sensed back-EMF. The inversely compensated output signal substantially provides a voltage to the amplifier sufficient to cause the amplifier to provide the drive output signal at a voltage corresponding to the voltage of the target speed voltage signal.

Voltage mode drive for control circuit for an actuator using sampled back EMF control

An apparatus for controlling an actuator having a moveable member and having a coil that influences movement of the member, by provision of a drive current to the coil in response to a target speed voltage signal. The invention includes an up/down counter, counting at a predetermined count rate and providing a count output. A control unit is provided for controlling the direction of count of the up/down counter depending on whether the voltage across the coil, sensed periodically a first predetermined interval after the drive current to the coil is interrupted, is greater than, or less than, a reference voltage having a predetermined relationship to the target speed voltage. A digital-to-analog converter is provided, responsive to the count output to provide a compensated voltage signal having a voltage corresponding to the count output. A voltage sensing and holding unit is provided that periodically, after the drive current is interrupted for a second predetermined interval, senses and holds a sample voltage corresponding to the voltage across the coil. A plus/minus indicator is provided that senses when the up/down counter is in a down count direction and is at a count of zero, and in response thereto changes between a plus state and a minus state. A switch node is provided, combining the sample voltage signal with the compensated voltage signal to produce a command voltage signal, and providing the command voltage signal with a polarity controlled by the state of the plus/minus indicator. Finally, a transconductance amplifier unit is provided, receiving the command voltage signal and providing the drive current to the coil in a direction determined by the state of the plus/minus indicator.

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Allen, TX, United States of America

John Kevin Rote