| 摘要 |
PROBLEM TO BE SOLVED: To reduce the number of timers for determining timings of executing various types of tasks for controlling motor drive.SOLUTION: A position detection unit 4 outputs a position detection signal Sa showing information on a rotor position of a motor 2. A microcomputer 7 controls drive of the motor 2 so that an actual revolution speed of the motor 2 calculated on the basis of the position detection signal Sa agrees with a target revolution speed. A PLL circuit 5 generates a variation clock signal CLK 1 having a frequency obtained by multiplying that of the position detection signal Sa. The oscillation circuit 6 generates a fixed clock signal CLK 2 having a fixed frequency. Operation clock supply means 13 supplies, as an operation clock, the fixed clock signal CLK 2 when the actual revolution speed of the motor 2 is equal to or lower than a determination threshold and the variation clock signal CLK 1 when the actual revolution speed of the motor 2 exceeds the determination threshold, to a CPU 11. The CPU 11 determines execution timings of various types of tasks according to the number of counts of the operation clock. |
