Other

Mitsubishi Denki Kabushiki Kaisha

Renesas Technology Corp.

Mitsubishi Electric Engineering Company, Limited

Hiroyuki Tamagawa

Satoshi Narumi

Toshiya Suzuki

Masaharu Hoashi

Satoshi Kusaka

Takahiro Yashita

Keisuke Kawakita

Kaori Ikuta

A motor drive apparatus includes a comparison circuit comparing voltages of 3-phase coil terminals and the voltage of a neutral point terminal of a 3-phase brushless motor to determine which voltage is higher/lower, a zero ampere current detection circuit detecting, based on the comparison result by the comparison circuit, that the coil current of a position detection phase becomes 0 A, a position detection circuit detecting a zero cross point of the voltage of the position detection phase based on the comparison result by the comparison circuit after the coil current becomes 0 A. Therefore, the zero cross point can be accurately detected without introducing a mask period.

Motor drive apparatus driving 3-phase brushless motor without using hall sensor

A motor driving circuit includes an induced voltage detecting circuit for detecting induced voltages in a motor; a rotation speed/phase detecting circuit and an output matrix circuit for generating a plurality of control signals in response to the detection result of the voltage detecting circuit; a current control circuit for generating current control command values in response to the control signals; and a current detecting circuit for detecting output currents that are driving the motor, and for controlling output transistors in response to its detection result and the current control command values. The motor driving circuit can sharply reduce the driving noise of the motor with improving the efficiency of the motor drive by shaping the output currents in a sinusoidal waveform.

Motor driving circuit

There is disclosed an apparatus for reducing motor driving noise, comprising: a selecting circuit for selecting and outputting a current increasing or reducing signal based on a commutation control signal; and a signal synthesizing circuit for synthesizing the current increasing or reducing signal selected by the selecting circuit with a current application control signal supplied to the power supply side switching element of at least a pair of switching elements.

Apparatus for reducing motor driving noise and method for generating motor driving noise reducing signal

A current path for a discharge current leading from ground to a motor is provided when a pulse width modulation (PWM) control is OFF, with a parasitic diode between a P type substrate of an NPN transistor and an N type collector region. A diode with a cathode and an anode connected to a base and an emitter of an NPN transistor is also provided, so that when the PWM control is OFF, a base current is conducted by the diode to the NPN transistor, whereby a current flows from the emitter of the NPN transistor to the collector, providing a current path for the discharge current from the motor to a power terminal.

IC output circuit based on a pulse width modulating system

A switching signal generator outputs a switching signal which indicates either an accelerating mode or a decelerating mode by comparing a motor control signal and reference voltage. A first activation signal generator and a second activation signal generator output a first activation signal and a second activation signal, respectively, according to the switching signal from the switching signal generator. A switching control signal generator outputs either a switching control signal based on a motor location signal or a desired electric potential according to the switching signal from switching signal generator, a first activation signal from the first activation signal generator and a motor location signal. When a power-supply side controller and an earth side controller are in a decelerating mode, power-supply side first, second, and third output transistors are non-conductive and first second and third earth side output transistors are conductive by supplying a base current based on a predetermined electric potential from the switching control signal generator.

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Tokyo, Japan

Hiroyuki Tamagawa