Matsushita Electric Industrial Co., Ltd.

Matsushita Electric Industries, Inc.

Makoto Gotou

Haruo Isaka

Yoshio Sakakibara

Akihiko Nakamura

Hideaki Mori

Kei Ichikawa

Masaaki Ochi

Kenichi Honjo

Toshio Inaji

Tatsuro Juri

Masaki Tagome

Hisanori Nagase

Kazuhiko Kobayashi

Masafumi Shimotashiro

Eiji Ueda

Yoshiaki Igarashi

Kiyokazu Hashimoto

Toshihiko Maruoka

Hiroshi Okamoto

Hiroshi Mitani

Akihiro Takeuchi

Tomokuni Iijima

Kazushige Narazaki

Susumu Yamaguchi

Shingo Fukamizu

Susumu Yamamoto

Shigeaki Matsubayashi

Ryo Akiyama

Kazutsugu Kobayashi

Hideki Nishino

Yoshiteru Hosokawa

Kenichiro Okumura

Takafumi Akeda

Keiji Nishihara

Hideo Nobekawa

A motor driver drives a motor composed of a rotor and plural-phase windings that generate a magnetic field for rotating the rotor, including: a plurality of transistors that operate as switches for supplying current to the windings; a position detector operable to detect a rotational position of the rotor, based on a terminal voltage of each winding; and a switching controller operable to have performed a switching method to turn the transistors to an ON state or to an OFF state for controlling the rotor at the predetermined speed by means of the position detector, wherein the switching controller further controls so as to force each of the transistors into the OFF state for a predetermined duration in a predetermined cycle, and the position detector detects only while the switching controller forcedly keeps the transistor in the OFF state.

Motor driver

A brushless motor has first and second power transistors which form current paths to three-phase windings so as to rotate a rotor. A position detecting part produces a position signal in response to a rotation of the rotor. An activation operation block controls active operation of the first and second power transistors in response to the position signal. The activation operation block includes a starting operation part which comprises an initial phase setting part, phase changing part and a phase correcting part. The initial phase setting part sets an initial phase of drive signals to the three-phase windings in response to the level of the position signal at the timing of a start signal. The phase changing part changes sequentially the phase of the drive signals to the three-phase windings in the positive direction in response to time. The phase correcting part corrects the phase of the drive signals to the three-phase windings in response to the occurrence of the rising and falling edges of the position signal. Therefore, the brushless motor with reduced position sensor can stably start the rotation of the rotor by using one position signal of one position sensor.

Brushless motor and disk drive apparatus

In a motor and a disk drive apparatus in accordance with the present invention, a position detecting partcomprises a detection signal switching circuitA, a noise elimination circuitand a detection circuitB, and the detection signal switching circuitA is configured to output an inverted detection signal obtained by logically inverting a detection signal until the rotation speed reaches a predetermined rotation speed after the beginning of starting or until a position detection pulse signal FG is detected a predetermined number of times; position detection operation is carried out only during the ON operation of PWM, whereby PWM sensorless starting is carried out.

Motor and disk drive apparatus

A disk drive apparatus reproduces a signal from a disk and/or records an signal on the disk. A position detecting part produces a position signal in response to a rotation of a rotor. An activation operation block controls active operation of first and second power amplifying parts in response to the position signal. A signal producing part produces a slope signal which repeats a slope waveform a plural times during one period of the position signal. The shaping part produces first and second activation control signals which responds with the slope signal. The activation operation block controls the first and second power amplifying parts responding with the first and second activation control signals. Therefore, an excellent disk drive apparatus with reduced acoustic noise and reduced vibration can be realized by using only one position signal of one position sensor.

Disk drive apparatus and motor

Power transistors of a power supplying part execute high-frequency switching operation and form current paths to three-phase windings so as to rotate the disk. A voltage detecting part produces a detected pulse signal responding with terminal voltages of the three-phase windings. An activation operation part controls active periods of the power transistors in response to the detected signal. A phase detecting part includes a slant producing part and a phase pulse producing part. The slant producing part produces a slant voltage signal which intermittently responds with a voltage difference between one of the power supplying terminal voltages and the common terminal voltage of the three-phase windings and has a voltage slant. The phase pulse producing part produces a phase pulse signal by comparing the slant voltage signal with a reference voltage. A commanding part produces a command signal which responds with the phase pulse signal. A switching operation block causes at least one of the power transistors to perform high-frequency switching responding with the command signal.

A motor comprising: Q-phase windings; voltage supplying unit; power supplying unit having Q first power transistors and Q second power transistors for supplying a power to said Q-phase windings; voltage detecting unit; state shifting unit; activation control unit; and switching operation unit. The switching operation unit includes switching control circuit for producing a main switching pulse and an auxiliary switching pulse, said switching operation circuit executing high-frequency switching operation of at least one second power transistor among said Q second power transistors responding with said auxiliary switching pulse signal when two first power transistors among said Q first power transistors simultaneously execute high-frequency switching operation responding with said main switching pulse signal while at least another second power transistor among said Q second power transistors executes an ON operation.

A disk drive apparatus reproduces a signal from a disk and/or records a signal on the disk. A position detecting part produces a single position signal in response to a rotation of a rotor. An activation operation block controls active periods of first and second power amplifying parts in response to the position signal. A signal producing part produces first and second activation control signals. The activation operation block controls the first and second power amplifying parts responding with the first and second activation control signals. Therefore, an excellent disk drive apparatus with reduced acoustic noise and reduced vibration can be realized by using only one position signal of one position sensor.

A disk drive apparatus reproduces an information signal from a disk and/or records an information signal on the disk. FET power transistors of a power supplying part execute high-frequency switching operation and form current paths to three-phase windings so as to rotate the disk. A voltage detecting part compares terminal voltages of the three-phase windings and produces a detected pulse signal in response to a comparison result. An activation operation block controls active periods of the FET power transistors in response to the detected pulse signal. A commanding part produces a command signal in response to an output pulse signal of the voltage detecting part. A switching operation block produces a switching pulse signal in response to a comparison result of a current-detection signal with the command signal, and causes at least an FET power transistor of the power supplying part to perform high-frequency switching in response to the switching pulse signal. The switching operation block changes a timing of the switching pulse signal in response to detection of the detected pulse signal so that the voltage detecting part can accurately achieve the next detection of the detected pulse signal. Further, an excellent speed control of the disk can be achieved by the accurate output pulse signal of the voltage detecting part.

A disk drive apparatus comprising Q phase windings; voltage supplying means; Q first power amplifying means, each one of which including a first power transistor; Q second power amplifying means, each one which including a second power transistor; altering signal producing means for producing altering signals; commanding means for producing a command signal; and switching operation means for producing a modified command signal which responds with said command signal of said commanding means and has a part varied in response to at least an output signal of said altering signal producing means, producing a current detected signal in response to a current to said Q-phase windings from said voltage supplying means, and causing at least one power transistor among Q of said first power transistors and Q of said second power transistors to perform high-frequency switching in response to said modified command signal and said current detected signal.

In a disk drive apparatus of the present invention, power transistors of a power supplying part execute high-frequency switching operation and form current paths to three-phase windings so as to rotate a disk, a position detecting part produces a position signal which responds with terminal voltages of the three-phase windings, an activation operation part controls active periods of the power transistors in response to an output signal of the position detecting part, a commanding part produces a command signal in response to an output pulse signal of the position detecting part, and a switching operation block produces a switching pulse signal in response to a comparison result of a current detection signal with the command signal. The activation operation part produces a slew-rate switching signal which responds with the switching pulse signal, and causes at least a power transistor of the power supplying part to follow the slew-rate switching signal, thereby executing high-frequency switching of the power transistor in response to the slew-rate switching signal.

FET power transistors of a power supplying part execute high-frequency switching operation and form current paths to three-phase windings. A voltage detecting part compares terminal voltages of the three-phase windings and produces a detected pulse signal in response to a comparison result. A state shifting part and an activation control part control active periods of the FET power transistors in response to the detected pulse signal. A commanding part produces a command signal in response to an output pulse signal of the voltage detecting means. A switching operation block produces a switching pulse signal in response to a comparison result of a current-detection signal with the command signal, and causes at least an FET power transistor of the power supplying part to perform high-frequency switching in response to the switching pulse signal. The state shifting part produces a timing signal after an adjust time from the detection of the detected pulse signal and shift-holds a holding state in response to the timing signal. The state shifting part changes the adjust time smaller in case that the command signal is larger than a predetermined value, thereby making the product value of the adjust time and the rotational speed smaller in the case.

Motor

A disk drive apparatus comprises three first power amplifying means; three second power amplifying means; three phase windings; a movable member; commanding means for outputting a command signal corresponding to a rotational speed of the movable member; and current detecting means for providing a current detected signal in response to a supply current supplied to the three-phase windings. A switching control means causes two of the three first power amplifying means to perform high-frequency switching simultaneously in response to the current detected signal and the command signal and causes two of the three second power amplifying means to perform high-frequency switching simultaneously in response to the current detected signal and the command signal.

In a motor and a disk drive apparatus using the motor, a switching control part produces a PWM pulse signal in response to the comparison result between a current detected signal and a command signal. An activate control part determines the active periods of power transistors in response to the holding state of the state holding part, and performs high-frequency switching operation to turn ON/OFF the power transistors in response to the PWM pulse signal of the switching control part. Furthermore, a voltage detecting part stops the detection of terminal voltages for a predetermined time in response to the PWM operation by the switching control part. After the stop, the voltage detecting part resumes the detection of the terminal voltages. This prevents improper detection caused by PWM noise.

A disk drive apparatus comprises a movable member having a field part for driving a disk. A current path is formed from a DC power supply into one winding of a Q-phase winding of the movable member by a first FET power transistor of a first power amplifier and a second FET power transistor of a second power amplifier. The first power amplifier amplifies an input current into a conduction control terminal side using the first FET power transistor. The second power amplifier amplifies the input current into the conduction control terminal side using the second FET power transistor. A switching control part simultaneously controls Q conduction control terminal sides of the first power amplifying means in an on and an off state and causes the first FET power transistor of the first power amplifying means to perform an on and off high-frequency switching.

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Nishinomiya, Japan

Makoto Gotou