| 摘要 |
PURPOSE:To generate a timing signal for designating an energizing timing of a phase coil in an accurate waveform even when noise is mixed from an electromotive force waveform of the phase coil for driving a sensor less type motor therewith. CONSTITUTION:A voltage U of a phase coil 11 is compared with a common potential N by a comparator 30, and a comparison output Cu is generated. The output Cu is enabled by a rising logic gate 31 and a falling logic gate 32 only during rising and falling of the voltage U to set a rising flip-flop 33 and a falling flip-flop 34. An output flip-flop 35 is alternately set and reset by respective outputs S1 and S2, and its Q output is, for example, produced as a timing signal Tu while the flip-flop 35 is being alternately set and reset. |
