| 摘要 |
PURPOSE:To effectively use the electric power of a sub-power source by provid ing a backup selecting means which individually selects whether or not the power supply is to be made to a plurality of ICs from a sub-power source and minimizing the power consumption of the sub-power source when the power supply is discontinued from a main power source. CONSTITUTION:This backup processor is composed of N pieces of backup ICs 7a-7n constituting a backup RAM 7, a main power source 9, and sub-power source 10. When the electric power of the main power source 9 is supplied, no electric power is supplied from the sub-power source even when one of switches SW1-SWn corresponding to an IC requiring backup is turned on, since a diode Ds is non-conducted. In case the switch corresponding to the IC requiring backup is turned on when the power supply is discontinued from the power source 9, the electric power of the sub-power source 10 is supplied to the IC. Therefore, the power consumption of the sub-power source which backs up the power supply to an IC, such as memory, etc., can be minimized. |
