| 摘要 |
PURPOSE:To perform time compensation at the time of power failure simply and surely by using a capacitor as a backup power source by making the device perform the temporary storage of the content of counting in a memory, the counting of a counter for power failure and other actions required at least. CONSTITUTION:When the main power source part 1 using a commercial power source 11 falls in the power failure, the transistor 51 of a power down sense 5 is turned off, while the transistor 52 is turned on reversely, and the gate 21 of a counting circuit 2 is opend, and thus the content of counting of a time-counting counter 21 is written in the RAM4. Meanwhile, an oscillator 7 for counting at power failure starts oscillation through the intermediary of the transistor 52, a counter 81 operating for the time of the power failure counts the time. After restoration from the failure, the content of counting of the counter 21 is corrected based on the content of the RAM4 and the counter 81. By the constitution wherein the feeding of power to the circuit, etc. required at least at the time of power failure, the time compensation for the timer at the power failure can be performed simply and surely by using the capacitor 63 as the backup power source. |
