| 摘要 |
<p>PURPOSE:To eliminate any hindrance even when the backup time of each device is different from the other, by installing a backup circuit having a backup power source and comparator which detects the voltage drop of the backup power source to each of plural devices. CONSTITUTION:Each of backup circuits CT1-CTn is installed to each of plural memory devices MB1-MBn. Backup permission/prohibition detecting signals indicating whether or not a backup operation is normally performed are outputted from the backup circuits CT1-CTn. These backup permission/prohibition detecting signals are supplied to a wired OR circuit formed by commonly connecting a signal line. By forming a backup device in such a way, no hindrance occurs even when the backup time of each device is different from the other.</p> |
