| 摘要 |
PROBLEM TO BE SOLVED: To provide a power supply synchronizing signal generating device which is not influenced by a noise overlapping a power supply voltage by interpolating one phase out of two phases remained when one phase of three phases can not be detected by a noise. SOLUTION: This device is constituted of a zero cross detector 1 detecting around three-phase zero cross of a three-phase four-line power source voltage, an or circuit 2 taking a logic sum of three outputs of the zero cross detector 1 a comparison circuit 4 comparing an output of the or circuit 2 with a counter value, a variable division circuit 5 increasing/decreasing a dividing ratio corresponding to the output of the comparison circuit 4 and dividing the output of a generator 15, a count maximum value determination circuit 6, a count circuit 3 counting an output of a variable divider 5 to an output of a count maximum value determination circuit 6 and outputting a count value, and a synchronizing signal generation circuit 10 generating the output of the zero cross detector 1, the output of the count circuit 3, the output of the count circuit 3 and the output of the comparison circuit 10. |
