Abstract: There is provided a drive control system for sensor-less motor wherein a multi-phase sensor-less motor is driven to rotate by switching a current to be applied to a field coil of each phase depending on the rotating phase of motor and such rotating drive is controlled with the PLL control method and the sensor-less motor is driven with higher reliability. When the motor is to be driven, a desired phase is selected as the detection phase and a voltage (Eu, Ev, Ew) induced on the coil of the detection phase is detected when the power is fed for a short period of time to the field coils except for that of the detection phase. A magnetic pole position of a rotor is detected from the amplitude condition of the detected induced voltage and the power feeding phase of the motor drive is determined based on the result of detection of the magnetic pole position.

Abstract: There is provided a drive control system for sensor-less motor wherein a multi-phase sensor-less motor is driven to rotate by switching a current to be applied to a field coil of each phase depending on the rotating phase of motor and such rotating drive is controlled with the PLL control method and the sensor-less motor is driven with higher reliability. When the motor is to be driven, a desired phase is selected as the detection phase and a voltage (Eu, Ev, Ew) induced on the coil of the detection phase is detected when the power is fed for a short period of time to the field coils except for that of the detection phase. A magnetic pole position of a rotor is detected from the amplitude condition of the detected induced voltage and the power feeding phase of the motor drive is determined based on the result of detection of the magnetic pole position.

Abstract: A pulse current having such a short duration as the rotor does not react is passed through field coils of respective phases of a brushless motor in first and second, mutually opposite, directions sequentially, voltages induced, by the pulse currents in two directions at each of the field coils of the non-conducting phase are combined, the polarity of a combined voltage is detected, and a field coil pair where a current is to be passed to start the motor is determined based on the result of detection for each of field coil of the non-conducting phase.

Abstract: There is provided a technique for controlling drive of a voice coil motor which can select, with priority for effective reduction, any one of heat generation and EMI noise which are presumed to induce a read/write error and for simultaneously realizing the positioning control of magnetic head with higher accuracy during the tracking operation and the high speed access with shortening of the seek operation period. The magnetic disc storage apparatus introducing this technique is provided with a mode to drive with linear control a coil of the voice coil motor from both terminals and a mode to drive one terminal of coil with linear control and the other terminal with pulse width control. Thereby, the coil is driven in the drive mode of linear control during the tracking operation, while one terminal of coil is driven with linear control and the other terminal with pulse width control during the seek operation.

Abstract: Currents of sine waveforms can be fed through coils by a relatively small-sized circuit, and thereby, highly dense magnetic storage can be realized with less rotation variations and a driving control circuit of a motor rotating at a low noise level can be provided. A coil of one phase of a three-phase brushless motor is driven with full amplitude at which an applied voltage becomes equal to a source voltage, and a coil of one of other phases is driven with gradually changing voltages so that a current of sine waveform is delivered, and a coil of the remaining phase is driven by feedback control so that a total current flowing through all coils becomes a predetermined current value.

Abstract: In a magnetic disk storage apparatus, when a drive current of the voice coil motor is small, the head drive control means executes the linear drive mode under which the voice coil motor is driven in a linear control manner, whereas when the drive current is large, the head drive control means executes the pulse drive mode under which the voice coil motor is driven in a pulse width control manner. Both modes are carried out by employing a commonly-used output amplifier that is arranged as a push-pull type output circuit made of both a push-driving output transistor and a pull-driving output transistor. An operation mode of this output amplifier is set to an AB-class operation during the linear drive mode, whereas the operation mode of this output amplifier is set to a B-class operation during the pulse drive mode.

Abstract: A pulse current having such a short duration as the rotor does not react is passed through field coils of respective phases of a brushless motor in first and second, mutually opposite, directions sequentially, voltages induced, by the pulse currents in two directions at each of the field coils of the non-conducting phase are combined, the polarity of a combined voltage is detected, and a field coil pair where a current is to be passed to start the motor is determined based on the result of detection for each of field coil of the non-conducting phase.

Abstract: A magnetic disc storage apparatus including a magnetic head for reading information from a storage track on a magnetic storage disc driven to spin, a voice coil motor for moving the magnetic head above the disc, and a magnetic head drive system for executing a position control of the magnetic head by controlling driving current of the voice coil motor by a feedback control while monitoring a state of reading the magnetic head in which the magnetic head drive system includes multi-mode driving means for executing a linear drive mode for controlling, as an analog amount, the driving current of the voice coil motor when an amount of driving to move the magnetic head is small and executing a pulse drive mode for controlling, as a digital amount, the driving current of the voice coil motor when the amount of driving to move the magnetic head is large.

Abstract: A pulse current having such a short duration as the rotor does not react is passed through field coils of respective phases of a brushless motor in first and second, mutually opposite, directions sequentially, voltages induced, by the pulse currents in two directions at each of the field coils of the non-conducting phase are combined, the polarity of a combined voltage is detected, and a field coil pair where a current is to be passed to start the motor is determined based on the result of detection for each of field coil of the non-conducting phase.

Abstract: A pulse current having such a short duration as the rotor does not react is passed through field coils of respective phases of a brushless motor in first and second, mutually opposite, directions sequentially, voltages induced, by the pulse currents in two directions at each of the field coils of the non-conducting phase are combined, the polarity of a combined voltage is detected, and a field coil pair where a current is to be passed to start the motor is determined based on the result of detection for each of field coil of the non-conducting phase.

Abstract: A pulse current having such a short duration as the rotor does not react is passed through field coils of respective phases of a brushless motor in first and second, mutually opposite, directions sequentially, voltages induced, by the pulse currents in two directions at each of the field coils of the non-conducting phase are combined, the polarity of a combined voltage is detected, and a field coil pair where a current is to be passed to start the motor is determined based on the result of detection for each of field coil of the non-conducting phase.

Abstract: A pulse current having such a short duration as the rotor does not react is passed through field coils of respective phases of a brushless motor in first and second, mutually opposite, directions sequentially, voltages induced, by the pulse currents in two directions at each of the field coils of the non-conducting phase are combined, the polarity of a combined voltage is detected, and a field coil pair where a current is to be passed to start the motor is determined based on the result of detection for each of field coil of the non-conducting phase.

Abstract: A motor drive method and apparatus for reducing noise of a motor. The motor drive apparatus includes first, second and third half bridge circuits. Each of the first, second and third half bridge circuits includes a first transistor which is adapted to form a current path between a first operational potential and an output terminal thereof and a second transistor which is adapted to form a current path between a second operational potential and the output terminal thereof. Each of the output terminals are connected to the corresponding drive coil of a motor. Each of the first and second transistors includes a control terminal to which a control signal is supplied.

Abstract: In a d.c. brushless motor drive circuit, the output amplifier produces a motor winding drive current with dulled rise/fall edges from a detected sinusoidal back e.m.f. voltage induced on the winding during the steady-state operation when the motor runs at the rated speed. The output amplifier includes a set of transistors each brought to a saturated conductive state or a cutoff state in accordance with the phase conduction sequence to connect one end of each motor winding to a ground voltage source, and another transistor operated continuously to connect the neutral point, which is opposite ends of the motor windings connected together, to a power voltage source.

Abstract: In a d.c. brushless motor drive circuit, the output amplifier produces a motor winding drive current with dulled rise/fall edges from a detected sinusoidal back e.m.f. voltage induced on the winding during the steady-state operation when the motor runs at the rated speed. The output amplifier includes a set of transistors each brought to a saturated conductive state or a cutoff state in accordance with the phase conduction sequence to connect one end of each motor winding to a ground voltage source, and another transistor operated continuously to connect the neutral point, which is opposite ends of the motor windings connected together, to a power voltage source.