摘要 |
A technique for smoothly speed-controlling a speed of a motor whose time constant is relatively small, such as a supersonic motor, under a relatively rough speed control profile and a simple configuration is disclosed. According to this technique, a frequency division number calculating section 1 changes a division number A under the relatively rough speed control profile and sets for a frequency division number setting register 2 . The comparator 3 outputs a+count signal if the division number A set by the frequency division number calculating section is greater than a current division number B counted by a frequency division number counter 4 (the division number A> the division number B), and outputs a-count signal if the division number A< the division number B. The frequency division number counter performs a+count on an enable clock of a time width t, which is shorter than the speed control profile of the frequency division number calculating section, if the+count signal is applied from the comparator, and performs a-count if the-count signal is applied from the comparator, and consequently counts the current division number B of a frequency divider 5 and applies this to the frequency divider.
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