| 摘要 |
PURPOSE:To prevent the noise of a rotation signal by providing a control amplifier of a transistor for switching an armature winding current and a constant- voltage circuit for stabilizing the power source of a Hall element. CONSTITUTION:A noise countermeasure circuit for a brushless DC motor is composed of transistors (Tr1-Tr2) for switching the armature windings L1-L2 of the motor, operational amplifiers OP1-OP2 for turning ON, OFF the Trs, Tr3 for leading a rotation signal, diodes D3-D4 for protecting, and a Zener diode ZD1, etc. A constant-voltage circuit VS is provided to stabilize a power source for the Hall element H and the amplifiers OP1-OP2 so as not to introduce a noise to the element H or the amplifiers OP1-OP2, thereby eliminating the noise to be superposed on a rectangular wave. Thus, an impulse noise can be removed. |
