| 摘要 |
PROBLEM TO BE SOLVED: To stabilize rotational characteristics of a driven brushless motor without lowering the rotational frequency band of the motor. SOLUTION: This motor driver takes in counter electromotive forces VU, VV, and VW which appear at each phase of a brushless motor 8 and a neutral voltage VN and then generates rectangular wave signals PU, PV, and PW, each including noise. The signals PU, PV, and PW are masked by a masking circuit 2 with noise masking signals VMASK output from a mask signal generating circuit 5. Based on the masked signals PU', PV', and PW', drive current is caused to flow in the brushless motor 8. Then, the motor driver detects the drive current by means of an output current detecting circuit 7 and then the masking signal generating circuit 5 varies the noise masking periods of the noise masking signals VMASKs , based on the detected drive current. |
