Abstract: A method of preventing concurrent or quasi-concurrent commutations of a pair of phase shift modulation (PSM) drive signals of an output bridge stage driving an electrical load includes establishing a threshold level of a programmed current level to be transmitted though the electrical load. The method also includes, if the programmed current level is lower than the threshold level, enhancing a time offset between commutation edges of the pair of PSM drive signals by a minimum time.

Abstract: A control apparatus for a supply device of a load, the supply device is of switching type and connected between a supply voltage and a reference voltage, the apparatus including a sigma-delta device having an input terminal at which is present a first digital signal and adapted to provide a pulse-density modulation signal at the output terminal; the sigma-delta device including a feedback circuit capable of sending to the input terminal of the sigma-delta device a second digital signal whose value depends on the value of the output signal, and the apparatus including a device capable of digitalizing the supply voltage and of providing a further digital signal. The feedback circuit includes a terminal capable of receiving the further digital signal, and the sigma-delta device having a gain such that the output digital signal is proportional to the inverse of the further digital signal.

Abstract: A control apparatus for a supply device of a load, the supply device is of switching type and connected between a supply voltage and a reference voltage, the apparatus including a sigma-delta device having an input terminal at which is present a first digital signal and adapted to provide a pulse-density modulation signal at the output terminal; the sigma-delta device including a feedback circuit capable of sending to the input terminal of the sigma-delta device a second digital signal whose value depends on the value of the output signal, and the apparatus including a device capable of digitalizing the supply voltage and of providing a further digital signal. The feedback circuit includes a terminal capable of receiving the further digital signal, and the sigma-delta device having a gain such that the output digital signal is proportional to the inverse of the further digital signal.

Abstract: An integrated control and power driving system moves a read/write head carrying arm over the surface of a disk. The integrated control and power driving system is applicable to a spindle motor, a mass storage disk drive and a voice-coil motor, for example, and includes a first chip and a second chip. The first chip integrates the output power stages driving the motors, and has an interface for outputting feedback signals representing functioning conditions of the voice-coil motor and of the spindle motor, and for receiving digital control signals of the output power stages. The second chip integrates logic drive and control circuitries of the power stages and an interface for receiving the feedback signals output by the first chip, and for transmitting to the first chip the digital control signals.

Abstract: A method of preventing concurrent or quasi-concurrent commutations of a pair of phase shift modulation (PSM) drive signals of an output bridge stage driving an electrical load includes establishing a threshold level of a programmed current level to be transmitted though the electrical load. The method also includes, if the programmed current level is lower than the threshold level, enhancing a time offset between commutation edges of the pair of PSM drive signals by a minimum time.

Abstract: A method for sensing a back electromotive force induced in a winding of a voice coil electro-mechanical actuator controlled in a discontinuous mode by alternating conduction phases to off-phases includes sensing voltage at terminals of the winding during an off-phase The winding is driven during a conduction phase immediately preceding the off-phase to invert, during a final portion of the conduction phase before entering an off-phase, a direction of flow of the current through the winding.

Abstract: An integrated control and power driving system moves a read/write head carrying arm over the surface of a disk. The integrated control and power driving system is applicable to a spindle motor, a mass storage disk drive and a voice-coil motor, for example, and includes a first chip and a second chip. The first chip integrates the output power stages driving the motors, and has an interface for outputting feedback signals representing functioning conditions of the voice-coil motor and of the spindle motor, and for receiving digital control signals of the output power stages.

Abstract: A method for sensing a back electromotive force induced in a winding of a voice coil electro-mechanical actuator controlled in a discontinuous mode by alternating conduction phases to off-phases includes sensing voltage at terminals of the winding during an off-phase The winding is driven during a conduction phase immediately preceding the off-phase to invert, during a final portion of the conduction phase before entering an off-phase, a direction of flow of the current through the winding.

Abstract: A method for estimating resistance of a DC motor for positioning read/write heads of a data storage disk is provided. The DC motor is controlled in an open-loop voltage mode through a motor controller input with a first signal for compensating positioning of the read/write heads onto the data storage disk. The first signal is generated based upon a position error signal representing a difference between a position of the read/write heads and a center of a track to be read. The method includes monitoring the first signal during a read operation of data being stored on the data storage disk, and estimating the resistance based upon spectral components of the first signal.

Abstract: A method for controlling in an open-loop voltage mode a DC motor driven through a power amplifier includes generating a control voltage for the DC motor to be input to the power amplifier based upon a difference between an external command and a correction signal, and amplifying the control voltage for generating a replica of an output of the power amplifier. A model of the DC motor is defined based upon electrical parameters of the DC motor. The method further includes estimating current flowing in the DC motor based upon the replica of the output of the power amplifier and the model of the DC motor, and generating the correction signal proportional to the estimated current.

Abstract: A method for estimating resistance of a DC motor for positioning read/write heads of a data storage disk is provided. The DC motor is controlled in an open-loop voltage mode through a motor controller input with a first signal for compensating positioning of the read/write heads onto the data storage disk. The first signal is generated based upon a position error signal representing a difference between a position of the read/write heads and a center of a track to be read. The method includes monitoring the first signal during a read operation of data being stored on the data storage disk, and estimating the resistance based upon spectral components of the first signal.

Abstract: A method for controlling in an open-loop voltage mode a DC motor driven through a power amplifier includes generating a control voltage for the DC motor to be input to the power amplifier based upon a difference between an external command and a correction signal, and amplifying the control voltage for generating a replica of an output of the power amplifier. A model of the DC motor is defined based upon electrical parameters of the DC motor. The method further includes estimating current flowing in the DC motor based upon the replica of the output of the power amplifier and the model of the DC motor, and generating the correction signal proportional to the estimated current.

Abstract: The device is for driving and controlling a rotation motor and a voice coil motor for a hard disk drive system that includes a disk and an arm carrying a read/write head to be positioned with respect thereto. A duty-cycle control loop including a current sensing circuit is connected to the voice coil motor, and an arm position control loop including a speed detection circuit is also connected to the voice coil motor. The duty-cycle control loop and the arm position control loop are digitally implemented by a DSP as a function of digital data representing a first analog signal generated by the current sensing circuit representative of current conducting in a winding of the voice coil motor, and a second analog signal generated by the speed detection circuit representative of an instant speed of the voice coil motor.

Abstract: The device is for driving and controlling a rotation motor and a voice coil motor for a hard disk drive system that includes a disk and an arm carrying a read/write head to be positioned with respect thereto. A duty-cycle control loop including a current sensing circuit is connected to the voice coil motor, and an arm position control loop including a speed detection circuit is also connected to the voice coil motor. The duty-cycle control loop and the arm position control loop are digitally implemented by a DSP as a function of digital data representing a first analog signal generated by the current sensing circuit representative of current conducting in a winding of the voice coil motor, and a second analog signal generated by the speed detection circuit representative of an instant speed of the voice coil motor.

Abstract: The definition of conversion of a digital value in a PWM signal using an N-bit up/down counter is improved by increasing the dimension of the input data to N+2 bits. This is done using the two Lsb's of the N+2 input data for selecting one among three intermediate levels between two consecutive values of an N-bit dynamic, according to a predefined table of combinations. The converter may still use an N-bit comparator. The system is particularly useful in driving a multi-phase brushless DC motor with each phase-winding singularly driven through a full-bridge output stage.

Abstract: The torque characteristic of an electrically driven brushless motor may be optimized by driving the phase windings of the motor with predefined, digitized and stored current or voltage profiles. Appropriate sequences of digital samples of the predefined driving profile are sequentially read from a nonvolatile memory where they are permanently stored to drive, through a DAC, the relative winding of the motor in synchronism with a signal representative of the rotor position.

Abstract: The sensing of BEMF signals in the motor's windings for synchronizing the phase switchings, in driving a brushless and sensorless motor with predefined constant voltage or current values or predefined voltage or current profiles stored permanently in a memory, is greatly simplified through a reconstruction technique that avails itself of the knowledge of the predefined drive values. The sensing does not require access to the center star point and is performed by sensing either the voltage difference between the terminals of two windings or of the current flowing in two windings, depending on whether a current or voltage mode is employed.

Abstract: Pre-defined driving profiles for the distinct phase-windings of an electronically controlled brushless motor are continuously reconstructed for each switching phase and forced in the form of a drive current or voltage on the respective windings, in synchronism with a signal indicative of the rotor position, from just a first complete sequence and at least a first sample of the successive sequence of a number of sequences, each of N samples, equal to the number of switching phases of the motor, in which is divided a complete digitized pre-defined profile. The digital samples are stored in a nonvolatile memory and that are scanned at a continuously regulated clock frequency and with varying order and direction of scanning for reconstructing the instantaneous driving profiles for all the windings.

Abstract: Synchronization of the phase switchings in driving a brushless motor with predefined excitation current profiles of substantially nonconstant value, is improved by continuously correcting the rotor position information detected by zero-cross detecting circuits with an updatable delay value. A switching delay counter is started by the raw zero-cross pulse to determine the generation of a corrected synchronization pulse. The delay counter is downloaded with a constantly updated value by monitoring the correction signal produced by a speed control loop and by incrementing or decrementing the downloaded value in the counter to minimize the correction signal.

Abstract: An integrated control and power driving system moves a read/write head carrying arm over the surface of a disk. The integrated control and power driving system is applicable to a spindle motor, a mass storage disk drive and a voice-coil motor, for example, and includes a first chip and a second chip. The first chip integrates the output power stages driving the motors, and has an interface for outputting feedback signals representing functioning conditions of the voice-coil motor and of the spindle motor, and for receiving digital control signals of the output power stages. The second chip integrates logic drive and control circuitries of the power stages and an interface for receiving the feedback signals output by the first chip, and for transmitting to the first chip the digital control signals.