| 摘要 |
PURPOSE: A brushless DC motor having an FG(frequency generator) pattern is provided to detect rotation direction by controlling the speed of the motor. CONSTITUTION: The output signal of a first FG pattern(41) is used as the input signal of a PLL(Phase-locked loop)(43) and a comparator(44). The output signal of a second FG pattern(42) is used as the other input signal of the comparator. The PLL receives the output signal of the first FG pattern and detects rpm and rotation speed which is used for controlling the speed of a brushless DC motor. The comparator compares the output signal of a first FG pattern and the output signal of the second FG pattern to detect the rotation direction of brushless DC motor.
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