Abstract: A voice coil motor (VCM) in a hard disk drive is operated in a discontinuous mode with an alternation of on and off times. A drive current to the VCM is facilitated and countered with a variable voltage across the during the on-times and off-times. The intensity of the drive current is controlled as a function of a Back ElectroMotive Force (BEMF) of the VCM. A method includes sampling during the alternation of on-times and off-times first and second values of the voltage across the VCM. The first value is sampled at a first time in response to the end of the off-time. The second value is sampled at a second time in response to the drive current of the VCM zeroing following the supply of drive current to the VCM being countered during the off-time. The BEMF is calculated as a function of first and second values.

Abstract: A voice coil motor (VCM) in a hard disk drive is operated in a discontinuous mode with an alternation of on and off times. A drive current to the VCM is facilitated and countered with a variable voltage across the during the on-times and off-times. The intensity of the drive current is controlled as a function of a Back ElectroMotive Force (BEMF) of the VCM. A method includes sampling during the alternation of on-times and off-times first and second values of the voltage across the VCM. The first value is sampled at a first time in response to the end of the off-time. The second value is sampled at a second time in response to the drive current of the VCM zeroing following the supply of drive current to the VCM being countered during the off-time. The BEMF is calculated as a function of first and second values.

Abstract: An embodiment method includes rectifying a back electromotive force of a spindle motor in a hard disk drive and energizing a voice coil motor in the hard disk drive using the rectified back electromotive force of the spindle motor via a voice coil motor power stage to retract a head of the hard disk drive to a park position. The head is retracted by moving the head towards the park position during a first retract phase and retaining the head in the park position during a second retract phase by applying a bias voltage to the voice coil motor power stage during a bias interval of the second retract phase. The method also includes producing a saturation signal indicative of onset of saturation in the voice coil motor power stage and controlling the bias voltage during the second retract phase.

Abstract: Embodiments provide a method of operating a voice coil motor via a transconductance loop. The method includes detecting an actual value of a supply voltage of the transconductance loop. An offset compensation signal of the transconductance loop is produced as a function of the detected actual value of the supply voltage based on a relationship between offset values and the supply voltage of the transconductance loop. The offset compensation signal is applied to a loop control signal of the transconductance loop. A drive current is applied to the voice coil motor. The drive current is related to a target drive current that is based on the loop control signal.

Abstract: An embodiment method includes rectifying a back electromotive force of a spindle motor in a hard disk drive and energizing a voice coil motor in the hard disk drive using the rectified back electromotive force of the spindle motor via a voice coil motor power stage to retract a head of the hard disk drive to a park position. The head is retracted by moving the head towards the park position during a first retract phase and retaining the head in the park position during a second retract phase by applying a bias voltage to the voice coil motor power stage during a bias interval of the second retract phase. The method also includes producing a saturation signal indicative of onset of saturation in the voice coil motor power stage and controlling the bias voltage during the second retract phase.

Abstract: A method of driving an electrical load includes coupling a power supply source to a power supply pin of a driver circuit, and coupling an electrical load to at least one output pin of the driver circuit. A driver sub-circuit of the driver circuit produces at least one driving signal for driving the electrical load. The at least one driving signal is provided to the electrical load via the at least one output pin. The at least one driving signal is modulated to supply the electrical load with a load current and to subsequently interrupt the load current. A compensation current pulse is sunk from the power supply pin, at a compensation circuit of the driver circuit, in response to the load current being interrupted.

Abstract: A method of controlling a half-bridge circuit includes receiving an analog feedback signal proportional to an output of the half-bridge circuit, comparing the received analog feedback signal with a threshold value, selecting a digital feedback signal based on a result of the comparing, comparing the digital feedback signal with a digital reference signal to generate a digital error signal, integrating the digital error signal to generate an integration error signal, downscaling the integral error signal to generate a downscaled integration signal, sampling the downscaled integration signal to generate a sampled integration signal, and generating pulsed signals from the sampled integration signal to provide an input to the half-bridge circuit.

Abstract: A method of driving an electrical load includes coupling a power supply source to a power supply pin of a driver circuit, and coupling an electrical load to at least one output pin of the driver circuit. A driver sub-circuit of the driver circuit produces at least one driving signal for driving the electrical load. The at least one driving signal is provided to the electrical load via the at least one output pin. The at least one driving signal is modulated to supply the electrical load with a load current and to subsequently interrupt the load current. A compensation current pulse is sunk from the power supply pin, at a compensation circuit of the driver circuit, in response to the load current being interrupted.

Abstract: A method of controlling a half-bridge circuit includes receiving an analog feedback signal proportional to an output of the half-bridge circuit, comparing the received analog feedback signal with a threshold value, selecting a digital feedback signal based on a result of the comparing, comparing the digital feedback signal with a digital reference signal to generate a digital error signal, integrating the digital error signal to generate an integration error signal, downscaling the integral error signal to generate a downscaled integration signal, sampling the downscaled integration signal to generate a sampled integration signal, and generating pulsed signals from the sampled integration signal to provide an input to the half-bridge circuit.

Abstract: A half-bridge control circuit comprises an input terminal, an output terminal for providing a pulsed signal to a half-bridge driver circuit configured to drive two electronic switches connected between two supply terminals, and a feedback terminal for receiving a feedback signal indicative of the instantaneous voltage value at a switching node between the two electronic switches. A selector circuit provides a digital feedback signal. A subtractor generates an error signal by subtracting the digital feedback signal from the reference signal. An integrator generates an integration signal by integrating the value of the error signal. A down-scale circuit generates a reduced resolution integration signal by discarding one or more least significant bits of the integration signal. A sampling circuit generates a sampled integration signal by sampling the reduced resolution integration signal. A pulse generator circuit generates the pulsed signal as a function of the sampled integration signal.

Abstract: An embodiment half-bridge control circuit comprises an input terminal, an output terminal for providing a pulsed signal to a half-bridge driver circuit configured to drive two electronic switches connected between two supply terminals, and a feedback terminal for receiving a feedback signal indicative of the instantaneous voltage value at a switching node between the two electronic switches. A selector circuit provides a digital feedback signal. A subtractor generates an error signal by subtracting the digital feedback signal from the reference signal. An integrator generates an integration signal by integrating the value of the error signal. A down-scale circuit generates a reduced resolution integration signal by discarding one or more least significant bits of the integration signal. A sampling circuit generates a sampled integration signal by sampling the reduced resolution integration signal. A pulse generator circuit generates the pulsed signal as a function of the sampled integration signal.

Abstract: A method for detecting the angular position of an electric motor includes: applying a first drive signal with a first polarity between first and second drive terminals that are coupled to respective stator windings of the electric motor; sensing at a third drive terminal a first signal resulting from the application of the first drive signal; applying a second drive signal with a second polarity between the first and second drive terminals, the second polarity being opposite the first polarity; sensing at the third drive terminal a second signal resulting from the application of the second drive signal; and producing a sum signal by summing the first and second signals, wherein the sum signal is indicative of an angular position of a rotor of the electric motor with respect to the stator windings.

Abstract: A method includes receiving an input digital signal and applying the input digital signal to digital filter processing with a corner frequency to produce a filtered output digital signal. The digital filter processing includes a set of multiplication operations using a set of filter multiplication coefficients. The set of multiplication operations is performed by alternately using a first set of approximate multiplication coefficients and a second set of approximate multiplication coefficients different from the first set of approximate multiplication coefficients. The approximate multiplication coefficients in the first set of approximate multiplication coefficients and the second set of approximate multiplication coefficients approximate multiplication coefficients in the set of filter multiplication coefficients as a function of negative power-of-two values. The alternating of multiplication operations results in digital filter processing with average corner frequency approximating the corner frequency.

Abstract: In an embodiment, a method for detecting the angular position of the rotor of an electric motor includes an inductive-sense procedure implemented by applying to the windings of the electric motor a time sequence of position-detection pulse signals, detecting a corresponding time sequence of response signals, integrating the response signals, and recording respective times taken by the response signals to reach an integral reference threshold. The position of the rotor is detected as a function of the respective times. The integral reference threshold is established by fixing a peak value, applying to the windings a calibration pulse, detecting the corresponding response signal and determining the time taken to reach the peak value. The integral reference threshold is selected as the integral of the response signal.

Abstract: An ohmic-inductive electrical load, such as an electric motor, for example, for a hard-disk drive, is driven by supplying thereto a load current via a switching power stage supplied with a source current delivered by a supply source. The driving action may include sensing the load current; estimating the source current starting from the load current sensed; generating a feedback signal that assumes different values as a function of the result of the comparison between the source current estimated and a source-current threshold value; and driving the switching power stage via the feedback signal, increasing or decreasing, respectively, as a function of the different values assumed by the feedback signal, the load current, thereby controlling the source current.

Abstract: A method for detecting the angular position of an electric motor includes: applying a first drive signal with a first polarity between first and second drive terminals that are coupled to respective stator windings of the electric motor; sensing at a third drive terminal a first signal resulting from the application of the first drive signal; applying a second drive signal with a second polarity between the first and second drive terminals, the second polarity being opposite the first polarity; sensing at the third drive terminal a second signal resulting from the application of the second drive signal; and producing a sum signal by summing the first and second signals, wherein the sum signal is indicative of an angular position of a rotor of the electric motor with respect to the stator windings.

Abstract: An apparatus for detecting a position of a rotor of a DC motor with N phases having a plurality of windings. The apparatus includes circuitry to couple at least two of the windings between a supply voltage and a reference voltage according to a first current path and allow the current stored in the two windings to be discharged through a second current path. The circuitry is configured to force the at least two windings at a short circuit condition in the second current path. The apparatus also includes a measurement circuit configured to measure the time period of discharging the current stored in the two windings and a rotor position detector for detecting the rotor position based on the measured time period.

Abstract: A control circuit controls the operation of a brushless DC (BLDC) sensorless motor having a first terminal connected to a first winding, a second terminal connected to a second winding and a third terminal connected to a third winding. A driver circuit applies drive signals to the first and second terminals and places the third terminal in a high-impedance state. The drive signals include first drive signals at a first current amplitude and second drive signals at a second, different, current amplitude. A differencing circuit senses a first mutual inductance voltage at the third terminal in response to the first drive signals and senses a second mutual inductance voltage at the third terminal in response to the second drive signals. The differencing circuit further determines a difference between the first and second mutual inductance voltages and produces a difference signal that is used for zero-crossing detection and rotor position sensing.

Abstract: A method includes receiving an input digital signal and applying the input digital signal to digital filter processing with a corner frequency to produce a filtered output digital signal. The digital filter processing includes a set of multiplication operations using a set of filter multiplication coefficients. The set of multiplication operations is performed by alternately using a first set of approximate multiplication coefficients and a second set of approximate multiplication coefficients different from the first set of approximate multiplication coefficients. The approximate multiplication coefficients in the first set of approximate multiplication coefficients and the second set of approximate multiplication coefficients approximate multiplication coefficients in the set of filter multiplication coefficients as a function of negative power-of-two values. The alternating of multiplication operations results in digital filter processing with average corner frequency approximating the corner frequency.

Abstract: An apparatus for detecting a position of a rotor of a DC motor with N phases having a plurality of windings. The apparatus includes circuitry to couple at least two of the windings between a supply voltage and a reference voltage according to a first current path and allow the current stored in the two windings to be discharged through a second current path. The circuitry is configured to force the at least two windings at a short circuit condition in the second current path. The apparatus also includes a measurement circuit configured to measure the time period of discharging the current stored in the two windings and a rotor position detector for detecting the rotor position based on the measured time period.