Matsushita Electric Industrial Co., Ltd.

Minebea Mitsumi Inc.

Toshiaki Seima

Koichi Tamai

Haruomi Morohashi

Hiromitsu Nakano

Masahiro Yasohara

Susumu Yamamoto

Tomoharu Yokouchi

Yukihiro Higuchi

Toshiki Tsubouchi

Naoya Murakami

Yoshiaki Iwayama

Kazuaki Saito

Takeshi Ohara

To improve the EMC performance of an electronic device on which a motor is mounted. A circuit board () comprises a substrate (), lands (P, P) that are formed on a main surface () of the substrate () and are for connecting a coil () of the motor (), a magnetic detection element () that outputs a detection signal corresponding to a position of a rotor () of the motor (), and a motor drive control IC () that generates drive signals (VOUTA, VOUTB) for driving the motor () based on the detection signal, wherein the magnetic detection element () and the motor drive control IC () are arranged in a region (AR) on a side of a minor angle (&#x3b8;) formed by a first straight line (a) and a second straight line (b) among regions that are on the main surface and are defined by the first straight line and the second straight line when viewing the substrate () from the main surface side, the first straight line connecting the land (P) and an axis of an output shaft of the motor (), the second straight line connecting the land (P) and the axis of the motor ().

Circuit board, motor unit, and fan

A circuit board for a motor unit equipped with a motor includes a substrate having a main surface being one of a pair of surfaces opposed to each other, and a back surface being another of the pair of surfaces, a magnetic detection element disposed in a predetermined region on an outer periphery side of the substrate on the main surface, and configured to output a detection signal in accordance with a position of a rotor of the motor, and a metal member formed between the outer periphery of the substrate and the magnetic detection element in the predetermined region on the main surface, and configured to receive a supplied ground voltage.

An impeller of this disclosure includes a hub having a ring shape; and a plurality of blades that are provided on an outer periphery of the hub, wherein the blade has a trailing edge formed such that an inner side of a radial width of the blade is curved in a direction opposite to a rotation direction, in a plan view as viewed in a direction of a rotation axis.

Impeller and fan including the impeller

A motor driving apparatus includes a pulse-width modulator and a PWM frequency switch for switching a carrier frequency of the modulator. The PWM frequency switch changes a carrier frequency in a start-up period of the motor to another frequency when the motor enters into a regular rotation. The carrier frequency in the start-up period is set at a lower level than that in the regular rotation period, so that the driving apparatus can reduce power-loss generated in the start-up period by switching actions of respective driving elements forming a first and a second drivers. In the regular rotation period, the driving apparatus performs PWM-driving with a high enough carrier frequency, so that the motor driven by this driving apparatus can realize accurate rotation.

Motor driving apparatus and motor using the same

In a driver of a brushless motor performing synchronous rectification PWM operation, switching is performed at an arbitrary timing between a synchronous rectification PWM operation and one-way PWM operation to prevent a negative current for the power supply, and thus preventing increase of a power supply voltage due to the negative current, thereby implementing high performance and high reliability.

Brushless-motor driver in PWM mode

A motor driving power supplying section obtains an output voltage by switching-controlling a predetermined voltage outputted from a main power supply and smoothing a voltage thus switching-controlled. A driving transistor group includes a plurality of driving transistors, for supplying electric power based on the output voltage of the motor driving power supplying section to the motor driving coils of multiple phases. A commutation control section supplies conduction switching signals to the driving transistor group so as to switch successive conduction states of the motor driving coils. An output control section controls the output voltage of the motor driving power supplying section so that a collector-emitter voltage of at least one of the plurality of driving transistors included in the driving transistor group has a predetermined value. A torque control section controls conduction current intensity to the motor driving coils by controlling output currents of the plurality of driving transistors included in the driving transistor group.

Control device for a brushless motor

A system for driving a brushless motor comprises motor drive coils belonging to a plurality of phases respectively, a plurality of pairs of drive transistors connected to the drive coils respectively, a distribution circuit for sequentially distributing drive-coil energization switching signals to the plural drive transistors respectively, a slope synthesizer for smoothing leading and trailing slope portions of the drive-coil energization switching signals so as to apply the smoothed energization switching signals to the drive transistors respectively through the distribution circuit, a voltage-controlled oscillator for supplying a signal having a suitable frequency as an input to the slope synthesizer, a phase error detector for detecting the phase difference between counter-electromotive voltages induced in the drive coils and the drive-coil energization switching signals in a driver-coil energization pause period, and an error amplifier for amplifying the output signal of the phase error detector and applying the amplified phase error signal as an input to the voltage-controlled oscillator.

Growing community of inventors

Yonago, Japan

Toshiaki Seima