PHASE LOCKED LOOP FOR CONTROLLING MOTOR AND SPINDLE MOTOR USING THE SAME

摘要

A PLL for controlling a motor includes first and second feedback loops. The first feedback loop includes an oscillator for generating a signal having a frequency corresponding to an input voltage, a first phase comparator for outputting a first phase difference signal corresponding to a phase difference between the signal from the oscillator and an input signal, and a first smoothing filter for smoothing the first phase difference signal to output the smoothed signal as the input voltage. The second feedback loop includes a second phase comparator for outputting a second phase difference signal corresponding to a phase difference between a signal having a frequency corresponding to a rotational speed of the motor and the input signal, an adder for adding the first and second phase difference signals, and a second smoothing filter for smoothing an output of the adder to output the smoothed signal to the motor.