| 摘要 |
PURPOSE:To enable a motor to be driven efficiently even if the rotational speed changes, in the drive circuit of a DC brushless motor without detection of position. CONSTITUTION:Comparators 201-203 receive the counter electromotive force of a motor M, and a trigger circuit outputs trigger signals G1 and G2 in cycle of 120 deg. synchronized to the rotation, and oscillation circuits generate two oscillation signals N1 and N2 synchronized to the rotation of the motor from these, and further a signal operating circuit 104 generates serial control signals CNT to become active/inactive at every 30 deg.. The control signal CNT is converted from serial to parallel into conversion control signals L1-L3 with a signal conversion circuit 105. A 120 deg. switching circuit 108 converts these further into drive signals K1-K6 and gives them to a current controller 300. Hereby. the motor is driven with a signal being delayed by 30 deg. in rotational angle independent of the revolution of the motor. |
