| 摘要 |
PURPOSE:To make it possible to extend as auxiliary power source to a maximum while reducing electric power consumption greatly by breaking an electric circuit that makes a chip-to-chip connection by closing an AND circuit on occurrence of a low-order signal accompaying a break of a main electric power source. CONSTITUTION:Once the failure of main power source 1 occurs owing to an accident, chip 2 is backed up by auxiliary power source 4 via diode 7. Consequently, information in the memory, counter, etc., formed in chip 2 is held accurately without being erased. On the other hand, since an ''L''-level signal accompanying a break of the main power source is applied to one input terminal of AND circuit 5 via signal line 10, circuit 5 is closed and the electric circuit making the connection between chips 2 and 3 is broken. Therefore, the loop of electric power source 4, chip 2, signal line 9, chip 3, input protection diode 6, and main electric power source 1 is not formed and no undesired current in the backup operation flows. Thus, the electric power consumption can be reduced greatly and the life of electric power source 4 can be prolonged to a minimum. |
