| 摘要 |
PURPOSE:To make a speed control by suppressing the power consumption and the heating of a control transistor by making a switching with a pulse width of duty corresponding to the number of revolutions. CONSTITUTION:A reference signal is selected by a motor speed change-over signal S1 through an inverter circuit 23, 'AND' circuits 24 and 25, and 'OR' circuit 27, and a reference signal of high speed side or a low speed side is inputted to a phase comparator 4. A switching circuit 28 does not operate at the high speed side, and an existing operation results. Frequency made by a divider 6' and the 'OR' circuit 22 and a signal having a pulse width are inputted to the switching circuit 28. The output of a phase compensation circuit 8 is switched with said pulse width as the switching circuit 28, and is inputted to a voltage controlling circuit 9 and is controlled. |
