Abstract: A motor rotation irregularity detection circuit includes a first integrator for integrating a rotation detection signal that is output from a driver of a sensor-less motor; a differentiator for outputting a difference between a binary signal based on the integral in the first integrator and the rotation detection signal; a second integrator for integrating an output signal of the differentiator; a comparator for making a comparison between the integral in the second integrator and a reference voltage to output an irregularity detection signal; and an output terminal for outputting a signal coming from the comparator.

Abstract: An aperture driving apparatus includes a swing unit and a stationary unit. The swing unit includes an aperture plate that partially blocks a light, a coil that constitute a voice coil motor for obtaining a driving force for driving the aperture driving plate, and a swing arm that supports the aperture plate and the coil and has a bearing portion between the aperture plate and the coil. The stationary unit includes a swing shaft that engages the bearing portion and swingably supports the swing arm about a swing axis, and a magnet and a yoke that constitute the voice coil motor together with the coil. A control unit of the aperture driving apparatus controls the swing angle of the swing arm using a closed-loop control technique. In the direction of the swing axis, the position of a center of gravity of the swing unit is substantially aligned with a position at which the driving force is applied to the coil.

Abstract: A motor rotation irregularity detection circuit includes a first integrator for integrating a rotation detection signal that is output from a driver of a sensor-less motor; a differentiator for outputting a difference between a binary signal based on the integral in the first integrator and the rotation detection signal; a second integrator for integrating an output signal of the differentiator; a comparator for making a comparison between the integral in the second integrator and a reference voltage to output an irregularity detection signal; and an output terminal for outputting a signal coming from the comparator.

Abstract: An aperture driving apparatus includes a swing unit and a stationary unit. The swing unit includes an aperture plate that partially blocks a light, a coil that constitute a voice coil motor for obtaining a driving force for driving the aperture driving plate, and a swing arm that supports the aperture plate and the coil and has a bearing portion between the aperture plate and the coil. The stationary unit includes a swing shaft that engages the bearing portion and swingably supports the swing arm about a swing axis, and a magnet and a yoke that constitute the voice coil motor together with the coil. A control unit of the aperture driving apparatus controls the swing angle of the swing arm using a closed-loop control technique. In the direction of the swing axis, the position of a center of gravity of the swing unit is substantially aligned with a position at which the driving force is applied to the coil.