| 摘要 |
PROBLEM TO BE SOLVED: To obtain a driving circuit that prohibits the increase of revolutions with a simple structure even if a power supply voltage exceeds a rated voltage, in a fan motor driven by a two-phase brushless motor. SOLUTION: This circuit is structured in such a way that a difference voltage between the power supply voltage and a preset voltage is detected, and that rotational speed is not caused to increase even if the power supply voltage exceeds the rated voltage by changing an element signal that controls the rotational speed in accordance with the difference voltage exceeding the rated voltage. |
