Abstract: A motor driver generates a signal synchronized with the rotation of a three-phase by comparing each of induction voltages generated in the motor's coils with a specified standard voltage. A triangular wave signal is generated such that its frequency increases with the speed of rotation of the motor increases. A standard value is set according to a change in the amplitude of the triangular wave signal and a noise mask signal is generated by comparing this standard value with the triangular wave signal. Noise is removed from the synchronized signals by using the noise mask signal, and currents are supplied to the coils of the motor by using the synchronized signals from which noise has been removed. With such a motor driver, noise can be effectively eliminated because both the noise mask time and the position detecting time can be varied gently.

Abstract: A motor driver generates a signal synchronized with the rotation of a three-phase by comparing each of induction voltages generated in the motor's coils with a specified standard voltage. A triangular wave signal is generated such that its frequency increases with the speed of rotation of the motor increases. A standard value is set according to a change in the amplitude of the triangular wave signal and a noise mask signal is generated by comparing this standard value with the triangular wave signal. Noise is removed from the synchronized signals by using the noise mask signal, and currents are supplied to the coils of the motor by using the synchronized signals from which noise has been removed. With such a motor driver, noise can be effectively eliminated because both the noise mask time and the position detecting time can be varied gently.