| 摘要 |
PROBLEM TO BE SOLVED: To provide the drive circuit of a three-phase BLDC(brushless direct current) motor and an index signal detection circuit where circuit size and expenses are reduced drastically and soft switching is achieved and the index signal of the motor can be generated with a simple circuit. SOLUTION: Soft switching is made by one sub magnet hole signal and three stair voltages being generated by a stair voltage generation circuit 20 using the signal. Also, a part where the strength of a polarity is weakened is provided at one portion of the specific pole of a sub magnet, a point where the hole signal detected from the sub magnet has the maximum value is detected by a pole detection circuit 50, a clock is generated, and one of clocks is used as an index signal when two clocks are generated during a half cycle. |
