| 摘要 |
PROBLEM TO BE SOLVED: To provide a brushless-motor driving circuit capable of being operated at variable speed without a sensor at desired speed. SOLUTION: The rotational speed of a brushless motor 51 is detected by a speed detector 15, and fed back to a speed compensation circuit 17. The target speed of the brushless motor 51 set to a speed setting circuit 16 is outputted to the speed compensation circuit 17. The duty ratio of chopper control is changed on the basis of the difference of both rotational speed and target speed in the speed compensation circuit 17, and the actual speed of the brushless motor 51 is corrected into target speed. Accordingly, the brushless motor 51 can be turned at desired speed. |
