| 摘要 |
PROBLEM TO BE SOLVED: To form a full-wave-driven trapezoidal wave with no spike, by a method wherein a triangular wave is generated by charging and discharging one capacitor repeatedly by means of a charging and discharging circuit and the triangular wave is reversed and then these waves are synthesized. SOLUTION: The output of a counter electromotive force detector 21 which detects counter electromotive force appearing in motor driving coils of a plurality of phases is converted into pulses of a plurality of channels. By charging and discharging one capacitor according to the output pulses, triangular wave is generated. Then, an output signal of a first phase extraction circuit 27 which extracts outputs signals of a charging and discharging circuit 24 with the output signal of one phase at a time according to the pulses of plurality of channels and an output signal of a second phase extraction circuit 28 which extracts output signals of a reversing circuit 26 with the output signal of one phase at a time according to the pulses of a plurality of channels are inputted into a signal synthesizing circuit 29 to form a trapezoidal wave. |
