| 摘要 |
<P>PROBLEM TO BE SOLVED: To obtain a drive circuit for a brushless DC motor which prevents overheating/burnout of an energizing control transistor and a stator winding, by decreasing an energizing current when heavily loaded or locked. <P>SOLUTION: The drive circuit for a brushless DC motor is provided with a comparison circuit to compare an output voltage of a revolution speed detection circuit with a reference voltage corresponding to a revolution speed when heavily loaded, and is constituted so as to decrease the base current of the energizing control transistor, by detecting that the output voltage of the revolution speed detection circuit is lower than the reference voltage by the comparison circuit, and to decrease the energizing current. <P>COPYRIGHT: (C)2003,JPO |
