Abstract: In accordance with an embodiment, a hard disk drive includes voice coil motors (VCMs) coupled to respective control units configured to drive retract an operation of the VCMs in the hard disk drive. The retract operation of the VCMs includes a sequence of retract steps. The control units are allotted respective time slots for communication over a communication line with the respective time slots synchronized via the common clock line, and are configured to drive sequences of retract steps of the VCMs in the hard disk drive in a timed relationship.

Abstract: An embodiment circuit comprises first and second output nodes with an inductor arranged therebetween, and first and second switches coupled to opposing ends of the inductor. The switches are switchable between non-conductive and conductive states to control current flow through the inductor and produce first and second output voltages. The current intensity through the inductor is compared with at least one reference value. Switching control circuitry is coupled with the first and second switches, the first and second output nodes, and current sensing circuitry, which is configured to control the switching frequency of the first and second switches as a function of the output voltages and a comparison at the current sensing circuitry. The switching control circuitry is configured to apply FLL-FFWD processing to produce the reference values as a function of a timing signal, targeting maintaining a constant target value for the converter switching frequency.

Abstract: An embodiment circuit comprises first and second output nodes with an inductor arranged therebetween, and first and second switches coupled to opposed ends of the inductor. The switches are switchable between non-conductive and conductive states to control current flow through the inductor and produce first and second output voltages. The current intensity through the inductor is compared with at least one reference value. Switching control circuitry is coupled with the first and second switches, the first and second output nodes, and current sensing circuitry, which is configured to control the switching frequency of the first and second switches as a function of the output voltages and a comparison at the current sensing circuitry. The switching control circuitry is configured to apply FLL-FFWD processing to produce the reference values as a function of a timing signal, targeting maintaining a constant target value for the converter switching frequency.

Abstract: In accordance with an embodiment, a hard disk drive includes voice coil motors (VCMs) coupled to respective control units configured to drive retract an operation of the VCMs in the hard disk drive. The retract operation of the VCMs includes a sequence of retract steps. The control units are allotted respective time slots for communication over a communication line with the respective time slots synchronized via the common clock line, and are configured to drive sequences of retract steps of the VCMs in the hard disk drive in a timed relationship.

Abstract: An embodiment circuit comprises first and second output nodes with an inductor arranged therebetween, and first and second switches coupled to opposed ends of the inductor. The switches are switchable between non-conductive and conductive states to control current flow through the inductor and produce first and second output voltages. The current intensity through the inductor is compared with at least one reference value. Switching control circuitry is coupled with the first and second switches, the first and second output nodes, and current sensing circuitry, which is configured to control the switching frequency of the first and second switches as a function of the output voltages and a comparison at the current sensing circuitry. The switching control circuitry is configured to apply FLL-FFWD processing to produce the reference values as a function of a timing signal, targeting maintaining a constant target value for the converter switching frequency.

Abstract: A dual-input, single-output low-dropout voltage regulator circuit includes: a first supply terminal, a second supply terminal and an output terminal, and first and second transistors having current paths coupled respectively between the first and second terminal and the output terminal. First and second drive circuit blocks are coupled respectively to the first and second supply terminals and drive the control terminals of the first and second transistors to provide a regulated voltage at the output terminal from the voltage on the first supply terminal and the second supply terminal. An input circuit block is sensitive to the voltage at the output terminal and is coupled to the first and second drive circuit blocks and configured to activate the second transistor to provide regulated voltage at the output terminal from the second terminal as a result of the voltage at the output terminal becoming lower than a desired value.

Abstract: A dual-input, single-output low-dropout voltage regulator circuit includes: a first supply terminal, a second supply terminal and an output terminal, and first and second transistors having current paths coupled respectively between the first and second terminal and the output terminal. First and second drive circuit blocks are coupled respectively to the first and second supply terminals and drive the control terminals of the first and second transistors to provide a regulated voltage at the output terminal from the voltage on the first supply terminal and the second supply terminal. An input circuit block is sensitive to the voltage at the output terminal and is coupled to the first and second drive circuit blocks and configured to activate the second transistor to provide regulated voltage at the output terminal from the second terminal as a result of the voltage at the output terminal becoming lower than a desired value.

Abstract: Applicant has recognized and appreciated the desirability of powering an actuator using power drawn from one or both of an energy storage device and a spindle motor. In some embodiments, following a loss of external power to a hard disk drive, the hard disk drive (or one or more components thereof) determines whether to provide the actuator with power drawn from the spindle motor or to provide the actuator with power drawn from the spindle motor and from the energy storage device. In some embodiments, the hard disk drive (or the component(s) thereof) may additionally or alternatively determine whether to charge the energy storage device using power drawn from the spindle motor. In some embodiments, the drive may make the determinations based on an amount of power that the actuator is to consume at a time and an amount of power that the spindle motor can provide at the time.

Abstract: Applicant has recognized and appreciated the desirability of powering an actuator using power drawn from one or both of an energy storage device and a spindle motor. In some embodiments, following a loss of external power to a hard disk drive, the hard disk drive (or one or more components thereof) determines whether to provide the actuator with power drawn from the spindle motor or to provide the actuator with power drawn from the spindle motor and from the energy storage device. In some embodiments, the hard disk drive (or the component(s) thereof) may additionally or alternatively determine whether to charge the energy storage device using power drawn from the spindle motor. In some embodiments, the drive may make the determinations based on an amount of power that the actuator is to consume at a time and an amount of power that the spindle motor can provide at the time.

Abstract: A system and method for determining the start position of a motor. According to an embodiment, a voltage pulse signal may be generated across a pair of windings in a motor. A current response signal will be generated and based upon the position of the motor, the response signal will be greater in one pulse signal polarity as opposed to an opposite pulse signal polarity. The response signal may be compared for s specific duration of time or until a specific integration threshold has been reached. Further, the response signal may be converted into a digital signal such that a sigma-delta circuit may smooth out glitches more easily. In this manner, the position of the motor may be determined to within 60 electrical degrees during a startup.

Abstract: A stepwise voltage ramp generator includes a tank capacitor, a terminal of which is coupled to a reference potential to be charged with a voltage ramp. A transistor couples the tank capacitor to a supply line. A diode-connected transistor, biased with a bias current is coupled to the transistor to form a current mirror. A by-pass switch is electrically coupled in parallel to the diode-connected transistor, and is controlled by a PWM timing signal, the duty-cycle of which determines a mean slope of the generated voltage ramp.

Abstract: A method for determining gain of a back-electromotive force amplifier may include setting an electric motor into a tri-state function mode and storing a first quasi steady-state value for back-electromotive force from the difference signal, and forcing a reference current through the electric motor and determining a first value of the gain of the amplifier for equaling a difference signal to the first quasi steady-state value. The method may further include setting the electric motor into a tri-state function mode a second time and storing a second quasi steady-state value for back-electromotive force from the difference signal, and increasing the first value of the gain by an amount proportional to a difference between the second quasi steady-state value and the first quasi steady-state value.

Abstract: A system and method for determining the start position of a motor. According to an embodiment, a voltage pulse signal may be generated across a pair of windings in a motor. A current response signal will be generated and based upon the position of the motor, the response signal will be greater in one pulse signal polarity as opposed to an opposite pulse signal polarity. The response signal may be compared for s specific duration of time or until a specific integration threshold has been reached. Further, the response signal may be converted into a digital signal such that a sigma-delta circuit may smooth out glitches more easily. In this manner, the position of the motor may be determined to within 60 electrical degrees during a startup.

Abstract: A method for determining gain of a back-electromotive force amplifier may include setting an electric motor into a tri-state function mode and storing a first quasi steady-state value for back-electromotive force from the difference signal, and forcing a reference current through the electric motor and determining a first value of the gain of the amplifier for equaling a difference signal to the first quasi steady-state value. The method may further include setting the electric motor into a tri-state function mode a second time and storing a second quasi steady-state value for back-electromotive force from the difference signal, and increasing the first value of the gain by an amount proportional to a difference between the second quasi steady-state value and the first quasi steady-state value.

Abstract: A stepwise voltage ramp generator includes a tank capacitor, a terminal of which is coupled to a reference potential to be charged with a voltage ramp. A transistor couples the tank capacitor to a supply line. A diode-connected transistor, biased with a bias current is coupled to the transistor to form a current mirror. A by-pass switch is electrically coupled in parallel to the diode-connected transistor, and is controlled by a PWM timing signal, the duty-cycle of which determines a mean slope of the generated voltage ramp.

Abstract: The method controls a charge pump generator having at least an output tank capacitor on which a regulated output voltage of the generator is produced, and a pump capacitor that is connected to a supply node and to ground during charge phases and is coupled in an anti-parallel configuration to the output tank capacitor during charge transfer phases, alternated to the charge phases. The method limits the current absorbed from the supply because the transfer capacitor is charged during at least an initial charge phase with a constant charge current of a pre-established value.

Abstract: The electric charge transferred in a charge transfer phase from the pump capacitor to the tank capacitor is diminished by reducing the amplitude of the voltage swing on the transfer capacitor proportionally to the current to be supplied. This is done by limiting the maximum voltage on the pump capacitor to a certain value. This maximum value is calculated to make the voltage on the transfer capacitor reach a certain minimum voltage at the end of the charge transfer phase. A charge pump generator includes a driving circuit that isolates the pump capacitor when the voltage on it reaches the maximum value.

Abstract: The electric charge transferred in a charge transfer phase from the pump capacitor to the tank capacitor is diminished by reducing the amplitude of the voltage swing on the transfer capacitor proportionally to the current to be supplied. This is done by limiting the maximum voltage on the pump capacitor to a certain value. This maximum value is calculated to make the voltage on the transfer capacitor reach a certain minimum voltage at the end of the charge transfer phase. A charge pump generator includes a driving circuit that isolates the pump capacitor when the voltage on it reaches the maximum value.

Abstract: The method controls a charge pump generator having at least an output tank capacitor on which a regulated output voltage of the generator is produced, and a pump capacitor that is connected to a supply node and to ground during charge phases and is coupled in an anti-parallel configuration to the output tank capacitor during charge transfer phases, alternated to the charge phases. The method limits the current absorbed from the supply because the transfer capacitor is charged during at least an initial charge phase with a constant charge current of a pre-established value.