| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a motor driving device which can generate rotational frequency signals for a six-pole motor. <P>SOLUTION: In a motor driving device, a rotation detection signal S3 asserted for every electric angle of 60 degrees is generated by comparing electromotive force generated in each end of coils of star-connected U, V, and W phases with mid-point voltage generated in a common connection node of the three coils. A first counter 22 is reset every time the rotation detection signal S3 is asserted to measure a cycle of the rotation detection signal S3. A comparison part 24 generates a first signal S11 which is asserted every time a count value D1 of the first counter 22 matches a value D2 indicating 1/2 of the cycle measured earlier. A second counter 30 generates a rotation frequency signal FG which is asserted every time the rotation detection signal S3 and the first signal S11 are counted a prescribed number of times. <P>COPYRIGHT: (C)2012,JPO&INPIT |
