Abstract: The present invention provides a VCM driver realizing low power consumption and high accuracy and a PWM amplifier compensating a dead time distortion. A phase compensator, a ?S modulator receiving an output signal of the phase compensator and converting the output signal to a control code of predetermined bits, a PWM modulator receiving the control code to produce a PWM signal, and an output circuit receiving the PWM signal to drive a voice coil constitute a forward path. A sense amplifier sensing a current of the voice coil, an ADC receiving an output signal of the sense amplifier, a low-pass filter receiving an output signal of the ADC, and a decimation filter receiving an output signal of the low-pass filter constitute a feedback path. An output signal of the decimation filter is fed back to the input side of the phase compensator to form a major feedback loop having a first-order characteristic loop gain.

Abstract: A position sensorless drive method capable of driving a permanent magnet motor by an ideal sine-wave current and enabling the driving from an extremely low-speed range in the vicinity of zero-speed is provided. A neutral-point potential of the permanent magnet motor is detected in synchronization with a PWM waveform of an inverter. The position of a rotor of the permanent magnet motor is estimated from the variation of the neutral-point potential. Since the neutral-point potential is varied in accordance with the magnetic circuit characteristics of an individual permanent magnet motor, the position can be detected regardless of the presence of saliency of the permanent magnet motor.

Abstract: High-accuracy overcurrent detection is performed, while a loss resulting from the current detection is significantly reduced. A switch section outputs the voltage between the both terminals of a current detection resistor using an AND signal between an output signal from a hysteresis comparator and an output signal from a pre-driver. The voltage is filtered by an electrostatic capacitor element and a resistor, and inputted to a comparator. The comparator makes a comparison between the signals inputted to the two input terminals thereof, and outputs the result of the comparison to a digital filter. When an overcurrent begins to flow in a power supply unit, the levels of the voltages inputted to the two input terminals of the comparator are inverted so that the comparator outputs an inversion signal to the digital filter. The digital filter outputs a detection signal to an overcurrent detection circuit when an arbitrary time has elapsed.

Abstract: A drive system of a permanent magnet motor is constituted of a mode switching trigger generator which monitors a state of a permanent magnet motor and issues a mode switching trigger, a conduction mode determining unit which receives the mode switching trigger and switches the mode of the permanent magnet motor, and a PWM generator which outputs a PWM signal to an inverter in accordance with the output of the conduction mode determining unit. The mode switching trigger is generated on condition that the speed electromotive force of the permanent magnet motor exceeds a constant or variable threshold value.

Abstract: The present invention provides a VCM driver realizing low power consumption and high accuracy and a PWM amplifier compensating a dead time distortion. A phase compensator, a ?S modulator receiving an output signal of the phase compensator and converting the output signal to a control code of predetermined bits, a PWM modulator receiving the control code to produce a PWM signal, and an output circuit receiving the PWM signal to drive a voice coil constitute a forward path. A sense amplifier sensing a current of the voice coil, an ADC receiving an output signal of the sense amplifier, a low-pass filter receiving an output signal of the ADC, and a decimation filter receiving an output signal of the low-pass filter constitute a feedback path. An output signal of the decimation filter is fed back to the input side of the phase compensator to form a major feedback loop having a first-order characteristic loop gain.

Abstract: This invention provides a motor driving apparatus that made it possible to reduce torque ripples including those attributed to load variation of the motor and an associated method for control of motor revolution. An output stage to a multiphase DC motor is comprised of power elements to supply output voltages to multiphase coils and a predriver to supply drive voltages to the power elements. A resistor means detects a current flowing through the power elements. A supply current detector detects a voltage signal produced across the resistor means as a supply current, using a high-speed ADC and a moving average filter. An output controller generates a PWM signal with a frequency lower than the frequency of the high-speed ADC so that the current detected by the supply current detector conforms to a current signal indicating a motor revolving speed and transfers the PWM signal to the output stage.

Abstract: The present invention provides a switching regulator having good stability compatible with a good response and an enhanced protection function. A first capacitor is placed between an output end of an inductor to generate an output voltage and a ground potential. From input voltage, a current is supplied to the inductor's input end by a first switch element. A first feedback path includes a hysteretic comparator. An output voltage added to a voltage proportional to the current flowing through the inductor is supplied to the hysteretic comparator which discriminates whether the voltage is appropriate by hysteresis characteristics and generates a PWM control signal in accordance with an output current variation. Moreover, a second feedback path is provided to feed back an error amplifier output voltage with greater gain in a low frequency domain and an attenuation loop around a PWM frequency band to the comparator's reference voltage input terminal.

Abstract: A drive control device of motor capable of starting up even a motor of such a type that the polarity of induced voltage does not switch every 180° of electrical angle or the polarity, positive or negative, does not occur with accuracy without causing a reverse rotation is provided. In a start-up control of motor, the following operation is performed: a current is passed through any coils in two phases, and the polarity of voltage induced in the non-conducting phase is detected. A conducting phase at start-up is determined based on the detected polarity of induced voltage. The average value of induced voltages in non-conducting phase detected with respect to the coils in respective phases is determined. The average value and the detected induced voltages are compared with each other, and relative polarities are determined from the magnitude relation with the average value to determine a conducting phase at start-up.

Abstract: A drive control device of motor capable of starting up even a motor of such a type that the polarity of induced voltage does not switch every 180° of electrical angle or the polarity, positive or negative, does not occur with accuracy without causing a reverse rotation is provided. In a start-up control of motor, the following operation is performed: a current is passed through any coils in two phases, and the polarity of voltage induced in the non-conducting phase is detected. A conducting phase at start-up is determined based on the detected polarity of induced voltage. The average value of induced voltages in non-conducting phase detected with respect to the coils in respective phases is determined. The average value and the detected induced voltages are compared with each other, and relative polarities are determined from the magnitude relation with the average value to determine a conducting phase at start-up.

Abstract: Control technique of a synchronous motor capable of suppressing rotation pulsation caused by individual difference without complicating control algorithm is provided. A pulsation generator superimposing a pulsation component anticipated in advance to a current command for the synchronous motor and a correction current generator superimposing a correction signal substantially having an average value of zero to the current command are provided in a synchronous motor control device. By this configuration, the correction signal suppressing a distortion component is superimposed to a value of the current command with a simplified control configuration. Torque pulsation is suppressed by determining the correction signal from difference between a detection current and a command current.

Abstract: A motor drive control device and motor startup method prevent startup noise and reduce startup time. At startup, a current to which a rotor does not react is passed through two phase coils of a polyphase DC motor in succession, and a voltage polarity induced in a non-conducting phase is detected. A first operation decodes the detected signal, and determines phase coils of the motor through which a current should pass to rotate the rotor and the energization direction. A second operation forms a control signal for passing a current according to the determination to drive the motor, detects a voltage peak induced in the non-conducting phase during the drive, and performs switching control of a conducting phase. In normal operation, the position of the rotor is detected based on a back EMF in each phase, and rotation control is performed.

Abstract: A control technology for a synchronous motor for suppressing rotational pulsation caused by variation in individuals without making a control algorithm complex is provided. In a motor drive system which is a control device for a synchronous motor, in order to suppress the pulsation component of N times as high as the AC frequency for driving the synchronous motor, a controller in which the phase property of the disturbance response of the controller with respect to the pulsation frequency is within ±45° is arranged. Therefore, the torque pulsation component generated from distortion in induction voltage or variation between phases is suppressed.

Abstract: A three-phase DC motor output stage including a predriver that supplies drive voltages to power MOSFETs supplies output voltages to three-phase coils, monitors whether each of gate-to-source voltages of the power MOSFETs is greater than or equal to a predetermined voltage and thereby detects a current zero cross, and employs the output of such current zero cross detection in PLL control for controlling energization switching timing and thereby forms drive voltages of 180-degree energization. Lower hooks with a voltage minimum phase as GND and upper hooks with a voltage maximum phase as a source are set as patterns alternately repeated for every electrical angle of 60 degrees. The patterns are expressed in linear approximation to generate sine wave-like drive voltages, thereby causing sine wave-like currents to flow into the three-phase coils.

Abstract: The Invention provides a motor drive semiconductor integrated circuit for driving and controlling a voice coil motor that can conduct a seek operation, a track follow operation and a settling operation through PWM control, has desired control accuracy and can be produced by a CMOS process. In a voice coil motor drive circuit (200) for executing positioning control of a magnetic head by feedback-controlling a driving current of a voice coil motor (108) for moving a magnetic head (106) over a magnetic disk for reading information from a storage track on the magnetic disk driven for rotation while a read state of the magnetic head is being monitored, head movement control such as a seek operation, a track follow operation etc, of the magnetic head is executed by PWM driving on the basis of a command value from a controller.

Abstract: The invention provides a motor drive semiconductor integrated circuit for driving and controlling a voice coil motor that can conduct a seek operation, a track follow operation and a settling operation through PWM control, has desired control accuracy and can be produced by a CMOS process. In a voice coil motor drive circuit for executing positioning control of a magnetic head by feedback-controlling a driving current of a voice coil motor for moving a magnetic head over a magnetic disk for reading information from a storage track on the magnetic disk driven for rotation while a read state of the magnetic head is being monitored, head movement control such as a seek operation, a track follow operation etc, of the magnetic head is executed by PWM driving on the basis of a command value from a controller.

Abstract: The present invention provides a switching regulator having good stability compatible with a good response and an enhanced protection function. A first capacitor is placed between an output end of an inductor to generate an output voltage and a ground potential. From input voltage, a current is supplied to the inductor's input end by a first switch element. A first feedback path includes a hysteretic comparator. An output voltage added to a voltage proportional to the current flowing through the inductor is supplied to the hysteretic comparator which discriminates whether the voltage is appropriate by hysteresis characteristics and generates a PWM control signal in accordance with an output current variation. Moreover, a second feedback path is provided to feed back an error amplifier output voltage with greater gain in a low frequency domain and an attenuation loop around a PWM frequency band to the comparator's reference voltage input terminal.

Abstract: The present invention provides a magnetic disk storage system including a spindle motor that rotates a magnetic disk, a spindle motor drive circuit that rotatably drives the spindle motor, a magnetic head that performs reading of information on the magnetic disk, a voice coil motor that moves the magnetic head, and a voice coil motor drive circuit that drives the voice coil motor. When the magnetic head is loaded from a standby position to the surface of the magnetic disk, the rotational speed of the spindle motor is made slower than a rotational speed at a normal operation. Upon power-off, the spindle motor drive circuit is caused to carry out a stepup converter operation to thereby generate a voltage higher than a back electromotive voltage, and causes a control circuit and a drive circuit to operate by the high voltage to thereby enable speed control at the movement of the magnetic head to a predetermined standby position.

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: A three-phase DC motor output stage including a predriver that supplies drive voltages to power MOSFETs supplies output voltages to three-phase coils, monitors whether each of gate-to-source voltages of the power MOSFETs is greater than or equal to a predetermined voltage and thereby detects a current zero cross, and employs the output of such current zero cross detection in PLL control for controlling energization switching timing and thereby forms drive voltages of 180-degree energization. Lower hooks with a voltage minimum phase as GND and upper hooks with a voltage maximum phase as a source are set as patterns alternately repeated for every electrical angle of 60 degrees. The patterns are expressed in linear approximation to generate sine wave-like drive voltages, thereby causing sine wave-like currents to flow into the three-phase coils.

Abstract: A three-phase DC motor output stage including a predriver that supplies drive voltages to power MOSFETs supplies output voltages to three-phase coils, monitors whether each of gate-to-source voltages of the power MOSFETs is greater than or equal to a predetermined voltage and thereby detects a current zero cross, and employs the output of such current zero cross detection in PLL control for controlling energization switching timing and thereby forms drive voltages of 180-degree energization. Lower hooks with a voltage minimum phase as GND and upper hooks with a voltage maximum phase as a source are set as patterns alternately repeated for every electrical angle of 60 degrees. The patterns are expressed in linear approximation to generate sine wave-like drive voltages, thereby causing sine wave-like currents to flow into the three-phase coils.