| 摘要 |
PROBLEM TO BE SOLVED: To surely start a motor when it is re-started by a method wherein, before the motor is put into a stand-by state, a reference voltage source is put into a stand-by state after an oscillation frequency of a voltage control oscillation circuit is reduced sufficiently. SOLUTION: In this sensorless motor drive circuit, a counter circuit 69 is counted up by an oscillation signal of a voltage control oscillator 67 and reset by a speed signal 3FG generated in accordance with a revolution of a motor, and a stop signal is applied to a current application logic circuit 57 to obtain a short brake state which reduces the revolution of the motor. When the oscillation signal of the voltage control oscillation circuit 67 is lowered, a reference voltage source 72 is turned off by a count signal generated by the counter circuit 69. |
