| 摘要 |
<p>PURPOSE:To prevent surely surreptitious use of stored contents in a volatile memory having a backup battery by connecting a power source and the battery in parallel and providing a switch which switches connection of the power supply terminal of the volatile memory. CONSTITUTION:A switch 2 switches connection of the power supply terminal of a volatile memory 1 to a power source-side contact (a) and an earth-side contact (b) and is normally connected to the contact (a). Consequently, the operating voltage of the memory 1 is supplied to the memory 1 from a power source 4 through a diode 6, and a voltage for holding stored contents is supplied to the memory from a backup battery 3 through a diode 5 when the power source 4 is turned off. In this case, if a cover or the like is removed for the purpose of stealing stored contents in the memory 1, this removal is detected, and the switch 2 is switched to the contact (b), and the charged electric charge in the memory 1 is discharged quickly, and stored contents disappear quickly, and thus, surreptitious use is prevented.</p> |
