| 摘要 |
PURPOSE:To control the speed of a motor in a wide range by providing a counter for detecting the length of a desired period of an encoder period. CONSTITUTION:Second and third counters 20, 21 are alternately reset to an initial value whenever an encoder signal is input. The counters 20, 21 outputs carriers when arriving at counted values corresponding to a desired rotating period of a motor to be stored in memory circuits 22, 23 erased by the encoder signal. The circuits 22, 23 detect longer and shorter signals than the desired period of an input period of the encoder signal. When the longer signal is generated, the input clock of a first counter 5 is switched to the clock of higher frequency than a reference clock to accelerate a carrier discharge phase of the counter 5 to increase a phase difference from the encoder signal, thereby increasing the energizing power of a motor. When the shorter signal is generated, the phase difference is reduced with the clock of lower frequency to properly set the motor energizing power. |
