Kabushiki Kaisha Toshiba

Shigeki Murai

Masatoshi Matsuda

The brushless motor driver includes a sample and hold circuit which samples and holds a first value of the first comparison signal in a first case in which a current is forced to flow from a first phase coil of the three-phase brushless motor to a second phase coil and no current is forced to flow to a third phase coil in a first period having a preset setting time and a second value of the first comparison signal in a second case in which a current is forced to flow from the second phase coil to the first phase coil and no current is forced to flow to the third phase coil in a second period having the preset setting time subsequent to the first period. The brushless motor driver includes an addition circuit which adds up the first value and the second value sampled and held by the sample and hold circuit and outputs an addition signal depending upon a result of the addition. The brushless motor driver includes a comparison output circuit which compares a value of the addition signal with a reference voltage and outputs a second comparison signal depending upon a result of the comparison. A position of a rotor in the three-phase brushless motor is discriminated on the basis of the second comparison signal.

Brushless motor driver and brushless motor system

A semiconductor integrated circuit for sensorless driving of a brushless motor, has: an induced voltage detecting circuit which includes a comparator for comparing a voltage induced in an exciting coil by a rotation of a rotor of the brushless motor with a midpoint voltage of the rotor of the brushless motor and outputting a detection signal corresponding to a comparison result, and detects a zero cross point where the induced voltage crosses the midpoint voltage; a logic circuit that outputs a control signal for controlling the brushless motor, in response to a command signal for regulating an operation of the brushless motor and an output signal of the comparator; and a power transistor circuit that supplies a driving current to the exciting coil.

Semiconductor integrated circuit for sensorless driving and sensorless driving system

A motor drive circuit includes a voltage generator configured to form a basic wave for generating sine-wave currents, wherein the voltage generator includes a resistor circuit for generating a plurality of voltages, a timing circuit for sequentially selecting selected ones of the plurality of voltages generated by the resistor circuit, and a switch circuit, connected to the resistor circuit and under control of the timing circuit, for outputting the sequentially selected voltages as the basic wave. A triangular wave generator generates a triangular wave which is applied along with the basic wave generated by the voltage generator to a modulation circuit, and the modulation circuit generates a terminal voltage for generating a sine-wave current.

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Kawasaki, Japan

Shigeki Murai