| 摘要 |
PROBLEM TO BE SOLVED: To suppress switching noise by providing means for setting an inclination determining a time variation to be limited and limiting the switching control signal based on the inclination. SOLUTION: In order to connect the DC level of counter electromotive force Uemf, Vemf, Wemf with a switching interval adjusting means, an inclination providing means 101-103 produces an inclination determining the time variation of a switching control signal by making a conversion into a signal swinging about the half value of power supply voltage Vcc and amplifying the signal. The switching interval adjusting means compares the outputs Uoh, Voh, Woh from the inclination providing means 101-103 using six comparators and further compares outputs Uol, Vol, Wol with a neutral voltage using three comparators. An output voltage level determining means produces a comparison output at a DC voltage level and switches the winding. |
