| 摘要 |
PURPOSE:To remove a wrong detection by outputting a correction driving pulse from correction driving pulse supply means when one of a first rotation detection signal storage circuit and a second rotation detection signal storage circuit does not store a rotation detection signal. CONSTITUTION:Coil opening and closing pulse supply means 20 changes over two driving inverters 18 and 19 to a detection mode under control. A detecting circuit 31 detects an induced voltage generated in a coil 28 to produce a rotation detection signal. A first rotation detection signal storage circuit 22 stores the rotation detection signal generated from the detecting circuit 31 when the one inverter 18 is in the detection mode. A second rotation detection signal storage circuit 33 stores the rotation detection signal generated from the other inverter 19. The supply means 20 changes over the modes of the inverters from the detection mode of the one inverter 18 to that of the other inverter 19 under control in response to the output signal of the storage circuit 22. When at least one of the storage circuits 22 an 23 does not store the rotation detection signal, a correction driving pulse is outputted from correction driving pulse supply means 50. Thus, a wrong detection is removed and a rotor can be prevented from running wild. |
