| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a motor drive circuit in which variations of the slew rate of motor driving signals are reduced. <P>SOLUTION: A permanent magnet position of a rotor of a brushless fan motor 18 is detected by a Hall element 14. The detected signals are converted to rectangular waves by a comparator 11. The rectangular waves are converted to the slew rate suitable for soft switching drive by an integral circuit 15. The integral signals are amplified respectively with an in-phase power amplifier 16 to amplify them in the same phase, and a reverse-phase power amplifier 17 to amplify them in the reverse phase. The brushless fan motor 18 is rotationally driven by supplying the amplified integral signals to a stator coil of the brushless fan motor 18. <P>COPYRIGHT: (C)2004,JPO |
