| 摘要 |
PURPOSE:To enable forming the device into a semiconductor integrated circuit and increase a starting torque and the maximum torque of braking by constituting the device by connecting specifically transistors forming a current mirror circuit and a differential amplifier. CONSTITUTION:When the rotational speed of the motor 9 increases and the counter electromotive voltage rises, the potential of a terminal 22 lowers, thereby collector current of a transistor 27 forming a current mirror through the intermediary of a transistor 23 forming a differential amplifier increases, while decreasing the base current of a transistor 14 connected with a power source terminal 21 and reducing the rotational number through the intermediary of transistors 11-13 forming the current mirror. Accordingly, the transistor 11-13 are fully saturated and thereby the maximum torque of braking can be increased, while the starting torque can also be increased by the use of the transistor 28. Moreover, by eliminating a resistance bridge, the formation of the device into the integrated circuit can be facilitated. |
