| 摘要 |
PURPOSE:To always maintain the winding applying voltage of a DC brushless motor constant without using a stabilized power source by controlling ON or OFF drive current switching means in response to the detection output of the applied voltage to the winding of the motor. CONSTITUTION:Unstable DC voltage of a power source circuit 8 is converted to 3-phase AC voltage through power transistors 4U-4W' controlled ON or OFF by rotor position detection signals from Hall elements 10U-10W, and applied to windings 1U-1W. The AC voltages are rectified by diodes 19U-19W, divided via resistors 20, 21, then integrated by an integrator which has a resistor 22 and a capacitor 23, and compared and amplified with a reference voltage of a DC power source 25 by a comparator 24. The compared output is compared by a comparator 27 with the output of a triangular wave generator 26 to vary the ON and OFF width of the transistor 9. For example, when the effective value of the winding supplying voltage increases, the output of the comparator 27 increases at the rate of high level, and the rate of the OFF of the transistor 9 increases. |
