| 摘要 |
<P>PROBLEM TO BE SOLVED: To reliably detect whether or not a sensorless motor is being rotationally driven as specified. <P>SOLUTION: Zero cross is a point at which induced voltage produced in each of the motor coils of respective phases provided in a sensorless motor and the neutral point voltage of the motor coils intersect each other. When such a zero cross is detected, a sensorless motor driving circuit selects and energizes the motor coils of the respective phases according to predetermined energization order, and thereby rotationally drives the sensorless motor. This driving circuit includes: a coil current variation detection unit that detects variation in the coil current passed through a motor coil to be energized during the energization period of the motor coil selected and energized when a zero cross is detected, and the motor coils of the respective phases are selected and energized according to the predetermined energization order; and a zero cross verification unit that verifies detected zero crosses through comparison of detected variation in the coil current with a predetermined criterion for variation in the coil current. <P>COPYRIGHT: (C)2008,JPO&INPIT |
