| 摘要 |
PROBLEM TO BE SOLVED: To prevent starting failure due to degradation of control resolution of the duty ratio generated as a result of a carrier cycle being decreased for low noise, and out-of-setting of over-current protection due to a decrease in ON duty. SOLUTION: This device is provided with the first operating mode and the second operating mode, whose timer 12 changes the duty ratio of the applied voltage of a motor and the carrier cycle which carries the duty ratio. At the second operating mode, the carrier cycle is set larger than at the first operating mode. |
