| 摘要 |
PURPOSE:To enable to effectively synchronize a DC brushless motor to the synchronizing speed by raising the rotating speed of the motor to a speed higher than the synchronizing speed and always flowing the current of the duty even if a PWM control is started, thereby smoothly lowering the speed to the synchronizing speed. CONSTITUTION:The position phase of a rotor as the output of a sensor is controlled by a PLLIC as a phase comparator with the phase of an external synchronizing signal outputted by frequency division from a crystal oscillator, thereby controlling the speed of a DC brushless motor. When the V input (input of the sensor) of a PLLIC exceeds in frequency an R input (external synchronizing signal), i.e., when it exceeds the synchronizing speed, a control signal output (1) using a PLL circuit is not outputted, but only the control signal (3) of the duty always presented is outputted. When it is lower than the synchronizing speed, the control signal of (1)+(3) is outputted. |
