| 摘要 |
PURPOSE:To make a motor smaller, improve the current efficiency, and reduce the torque ripple by installing a two-phase full wave drive circuit to drive a two-phase coil based on a signal from a signal processing circuit and a rotational speed control circuit to control the rotational speed of the motor according to a rotation signal from an FG generator. CONSTITUTION:After the output of a magnetism detection element 11 is inputted to an amplifier 12, the amplified output is sent to a waveform shaping circuit 13 having a threshold characteristic on the upper and lower sides of the output waveform thereof for waveform shaping. The shaped waveform is processed by arithmetic processing with a signal processing circuit 18, the result is transmitted to a drive circuit 19, and two-phase full wave 180 deg. el drive is performed. When the rotational speed exceeds the fixed value for accurate rotation, the number of pulses obtained from an FG generator 14 is divided into a twice as large number as that of the pulses of a drive magnet with a frequency dividing circuit 15 and separated with a separation circuit 16. The number is processed by arithmetic processing with the signal processing circuit 18 through a switching circuit 17. |
