| 摘要 |
PROBLEM TO BE SOLVED: To provide a motor control circuit for enhancing the efficiency of a fan motor or the like while reducing the motor noise and switching noise. SOLUTION: The motor control circuit for rotating a rotor by turning output transistors 8, 9 on/off to feed a current periodically to motor coils 10, 11 comprises a pole position detection element 3 for outputting a signal depending on the rotation of rotor, a differential amplifier 4 for amplifying the output signal from pole position detection element 3, a circuit 102 for advancing the phase of output from the differential amplifier 4, and a zero-cross comparator 103 for converting the output from phase lead circuit 102 into a pulse. The motor control circuit further comprises a logic circuit 104 for detecting the phase lead of zero-cross comparator 103, and a circuit 105 for turning the output transistors 8, 9 on/off to interrupt the conduction current of motor coil 10, 11 at the final stage of each period using the output from the logic circuit 104. |
