| 摘要 |
PURPOSE:To prevent the hunting phenomenon of a DC motor at the high load torque time by switching the current distribution rate of a current distributor in response to the current signal flowing through the motor. CONSTITUTION:A current distributor 31 is composed of the first motor driving transistor unit 23 which has a transistor 5, and transistors 9-11, 22 forming a current mirror in which the bases are connected commonly to the base of the transistor 5, and the second motor driving transistor unit 30 which has transistors 27-29. The motor current Ia is small at the light load torque time and the current flowing through the transistor unit 23 is small. Accordingly, the voltage drop of the resistor 32 is small, and no current flows through the transistor unit 30. When the load torque increases, the voltage drop of the resistor 23 increases, and the current flows through the transistor 30. |
