| 摘要 |
PURPOSE:To effectively prevent the variation of the rotating speed of a brushless DC motor by excluding the first rotation detection signal obtained immediately after switching the energization and deenergization from the object of discriminating the conditions of the energization and deenergization. CONSTITUTION:A rotating speed and the phase of a motor M are detected and fed back by a Hall sensor 4 to the speed detector 5. The output signal of the speed detector 5 which receives the reference clock from a reference signal generator 7 is inputted to a drive circuit 6, the phase of the motor M is switched by selecting the drive transistor, the speed signal A from the speed detector 5 is inputted to a pulse inhibit circuit 9, and the timing clock B is inputted to the reference signal generator 7. The ON or OFF signal E of the exciting current is outputted from a comparator 8 which receives the signal D produced by removing the first signal immediately after switching the energization and the deenergization for affecting adverse influence to the speed control of the speed signal A by a pulse inhibit circuit 9 and the reference signal C from a reference signal generator 7 to the drive circuit 6. |
