| 摘要 |
PURPOSE:To eliminate the need for mounting current detecting resistors and comparators at every each phase, and to simplify constitution by controlling exciting currents by the and of the output of the comparators comparing the exciting currents and an instruction waveform and phase selective signals. CONSTITUTION:When two-phase excitation, a level holding circuit 2 is not operated. A triangular wave from a triangular wave generating circuit 1 is inputted to the comparator 4 as the instruction waveform through an integration circuit 3 under this condition. The comparator 4 compares the instruction waveform and voltage detected by means of the winding current detecting resistor 10, and outputs a pulse row. A drive switching element 5 is at on when the output pulse is at a low level, and phase selective switching elements 6c, 6d are at off by means of a wired and circuit 9. When the output pulse is at a high level, on the other hand, the drive switching element 5 is at off, and the phase selective switching elements 6c, 6d are at on or off by the output of drivers 8c, 8d. |
