| 摘要 |
PURPOSE:To always automatically obtain an interrupt signal adapted for a power source frequency by switching a 50Hz and 60Hz interrupt signal generator according to the output of a discriminator which discriminates whether the supply power source is 50Hz or 60Hz. CONSTITUTION:A 50Hz interrupt signal generator 3, a 60Hz interrupt signal generator 4, a discriminator 5 which discriminates whether the supply power source is 50Hz or 60Hz and a switching circuit 6 are provided in a phase control signal generator which forms a phase control signal with an interrupt signal synchronized with a power source frequency as a time reference. Accordingly, the power source frequency is discriminated to automatically switch the interrupt signal generator adapted for it to apply it to a phase control signal forming unit, thereby obtaining a phase control signal, and the circuit is formed all of a hardware to alleviate the load to the software when performing a microcomputer control. |
