| 摘要 |
PROBLEM TO BE SOLVED: To provide a short break signal transmission circuit which has a function of maintaining the operation of a device securely in accordance with a period during which the output can be held at the time of a short break. SOLUTION: An AC input cut-off detection circuit 4 detects the cut-off of an AC input 1. A primary side circuit current is converted into a voltage by a current detection circuit 6 and its level is detected by the A/D converter of a CPU 8. The level of a voltage between the terminals of an input smoothing capacitor 3 is detected by the A/D converter through a voltage level transformation circuit 5. Relations between the detected primary side circuit current, the voltage level of the input smoothing capacitor and the holding time are inputted to the ROM of the CPU 8 in the form of matrix. When the cut-off of the AC input is confirmed, the data of the holding time is read out in accordance with the terminal voltage of the input smoothing capacitor and the primary side circuit current which are detected by the A/D converter. A short break signal 9 is transmitted directly to a load device from the CPU 8 with a timing by which the holding time long enough to enable to finish the process of the operation of the load can be secured. |
